PERLITE

Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian.
It occurs naturally and has the unusual property of greatly expanding when heated sufficiently.
It is an industrial mineral, suitable “as ceramic flux to lower the sintering temperature”, and a commercial product useful for its low density after processing.

Perlites are small pebbles of natural glass which contain a small amount of occluded water, and are found in volcanic deposits.

EC / List no.: 603-442-8
CAS no.: 130885-09-5
AMORPHOUS ALUMINO SILICATE
dialuminum;dipotassium;disodium;dioxosilane;iron(3+);oxocalcium;oxomagnesium;oxygen(2-)
PERLITE

EC / List no.: 618-970-4
CAS no.: 93763-70-3
Amorpohous Alimina Silicate
Perlite, expanded

IUPAC names
Aluminiumsilikat
Amorpohous Alimina Silicate
dialuminiumtrioxide
Perlite
Perlite, Expanded
Perlite, expanded

Trade names
Filter aid, Harborlite|r 800S

Other names
amorphous alumina silicate
Expanded Perlite
Perlite

Perlite is an Amorphous mineral consisting of fused sodium potassium aluminum silicate, with variable chemical composition and 1% quartz Perlite uses and applications include: In abrasives, acoustical plaster and tile, wallboard, charcoal barbecue base, cleanser base, filter aids, metal foundries, refractory products; as packaging material; as soil conditioner; hydroponic agriculture substrate; lightweight concrete aggregates; wallfloor insulation; as filler in construction materials; as inert carrier for pesticidesfertilizers; in chemical, steel, and food industries

Perlite, obsidian, and pitchstone are volcanic glasses that differ in water content: obsidian, less than 2% H2O; perlite, 2–5%; and pitchstone, more than 5%.
The general range of composition (Bush 1973, p. 341) is 70–75% SiO2, and about 10–15% Al2O3.
The water content is critical to expansion, but obsidians with as little as 0·2% H2O are reported to have expanded satisfactorily.
Originally, perlite meant a glassy rock characterized by concentric cracks, but commercial usage includes any glassy rock (except pumicite) that can be expanded by heating to about 2000 °F (1100 °C).

Perlite is a substance that has many commercial and industrial uses.
Also known as volcanic glass, perlite is used in agriculture, shipping, medicine and a host of other applications.

What is Perlite?
Perlite is a volcanic rock mined in the United States, as well as other countries like Turkey.
The volcanic glass, or perlite, is formed when lava (molten rock) spews out of a volcano, and cools in a rapid manner.
Because of rapid cooling, water is trapped within the rock, and the lava forms into a glass-like structure.
Perlite contains 2 to 5 percent water and is a silicate rock, meaning it contains a “high percentage of silica (Si)”

Perlite in its crude state bears little resemblance to the expanded product once it has been processed.

Expanded – Milled Perlite
Typical Chemical Analysis (% by weight unless otherwise stated)
SiO2 74,0% – 78,0%
Al2O3 11,0 % – 16,0 %
Fe2O3 0,4% – 1,0%
TiO2 0,0% – 1,0%
MgO 0,0% – 1,0%
CaO 0,5% – 1,0%
Na2O 1,0% – 4,0%
K2O 1,0% – 5,0%
L.O.I. 2,0% – 6,0%

Please contact us for various mesh sizes, specs and applications.
We can also sell PERLITE ORE in Turkey.

USES
Perlite’s uses depend on the field of application:

Industry
Agriculture
Construction
Cryogenics: expanded perlite is an excellent insulator for low or very low temperature cryogenic systems. It is widely used in LNG (Liquefied Natural Gas) isolation tanks, noble gas tanks, oxygen, nitrogen, argon etc. in cryogenic state.
Mortars and refractory elements: perlite is used as an ingredient in low to medium temperature refractory elements (up to 850°C) and it is used to build and/or coat ovens, furnaces, etc., and as a bonding material for joining refractory pieces.
Isolation: passive fire protection. The manufacturing of mortars, plates and various accessories. Ceramic furnaces.
Filtration: one of the most common uses of expanded perlite is as a filtering agent. The expanded and processed ore is chemically inert, and does not transfer taste, colour or odour to the filtrate. There is a wide range of perlite filters for various products such as beer, wine, water, oils, chemicals etc.
Fire protection system petrochemical industry.
Substrates-peat: perlite can be mixed with all kinds of organic substrates, providing them with a distinct capacity to be well aerated. The structure of perlite remains unchanged over time and helps to regulate water consumption by acting as a reservoir.
Hydroponics: of all the materials used for soilless cultivation, expanded perlite is the most important. In fact, several studies have shown that outstanding crops can be achieved with perlite hydroponic systems.
Animal nutrition: perlite acts as a binding, anti-caking and coagulant agent. Due to its high absorption capacity, perlite is used to support and carry a wide variety of nutrients, fatty acids, vitamins and antibiotics used in the preparation of additives for animal feeds.
Gypsum: perlite is a basic ingredient in the development of new lightweight projected gypsum mortars.
Monolayer Mortars: perlite is a basic ingredient in the manufacturing of projectable monolayer finish mortars.

Perlit is used as a substrate agent in soil aeration, steel layering, advancement of hydration level of soil, spreading of fertilizer, as well as in enhancing the physical attributes of flower and pot soil.

WHY TO USE PERLITE IN AGRICULTURE?

» Perlite ensures soil aeration and improves its drainage with over 90% porosity and around 60% aeration porosity.
» Perlite provides economic irrigation.
» It does not carry weed seed or illness thanks to its inorganic structure.
» Perlite does not cause saltiness and alkalization problems thanks to highly reduced amount of soluble ions contained.
» It regulates the PH of the soil easily as it is neutral (PH=6.5-7.5).
» Thanks to its low heat conductivity, it minimizes the harmful effect of daily temperature changes on the plant.
» In soilless agricultural activities, it ensures protection of its properties after sterilization offering 5-6 years of use life. It provides early cultivation of yields.
» It prevents damage and loss at seedling roots.
» In order to eliminate the problems experienced in the greenhouse soils which gradually become exhausted, perlite use in soilless agricultural applications have increased over the recent years.

Perlite has been extensively used as a lightweight aggregate material in concrete or mortar. In expanded form perlite offers thermal insulation, fire resistance and other desirable properties when used in portland cement- or gypsum-based plaster. The authors review current applications, with particular reference to lightweight fibre-reinforced composites based on cement/gypsum plaster and perlite binder. The availability of local supplies of perlite has promoted interest in its use in India but progress has been hampered by a lack of local knowledge and Standards. A brief description is given of an ongoing research project examining the effect of litemix and fellite perlite aggregate on the properties of a plain gypsum plaster and a new water-resistant gypsum binder reinforced with glass fibre.

Gypsum perlite
Abstract
FIELD: construction.
SUBSTANCE: gypsum perlite contains a gypsum binder, such as a processed mechanically activated phosphogypsum ground to 5-40 mcm (active gypsum), hydrophobizated swollen sand, superplasticiser Melflux at the following ratio of components, wt %: active gypsum – 84.8-93.8%, hydrophobizated swollen perlite sand – 6-15%, superplasticiser – 0.2%.
EFFECT: improved heat insulation and strength properties at low prime cost.
1 tbl

Effect of expanded perlite on the mechanical properties and thermal conductivity of lightweight concrete
Author links open overlay panelOzkanSengulaSenemAzizibFilizKaraosmanoglubMehmet AliTasdemira

Abstract
The main objective of this study is to provide more data on the effects of expanded perlite on the mechanical properties and thermal conductivity of lightweight concrete.
In the experimental program, mixtures were prepared by partially replacing natural aggregate by expanded perlite and as a result, unit weights of lightweight concretes in fresh state varied between 700 and 2000 kg/m3. Water to cement ratio was kept constant in all mixtures. Compressive strength, modulus of elasticity, water absorption and capillarity coefficient of the mixtures were determined. Thermal conductivity of the specimens was also obtained. Test results show that the compressive strength and modulus of elasticity decreases with increasing in perlite content. Water absorption and sorptivity coefficient, however, increase with the higher perlite contents. The test results indicate that the thermal conductivity is substantially improved with the use of perlite and a strong relationship between thermal conductivity and unit weight is obtained.

Properties

Perlite softens when it reaches temperatures of 850–900 °C (1,560–1,650 °F).
Water trapped in the structure of the material vaporises and escapes, and this causes the expansion of the material to 7–16 times its original volume.
The expanded material is a brilliant white, due to the reflectivity of the trapped bubbles.
Unexpanded (“raw”) perlite has a bulk density around 1100 kg/m3 (1.1 g/cm3), while typical expanded perlite has a bulk density of about 30–150 kg/m3 (0.03–0.150 g/cm3).

Typical analysis
70–75% silicon dioxide: SiO2
12–15% aluminium oxide: Al2O3
3–4% sodium oxide: Na2O
3–5% potassium oxide: K2O
0.5-2% iron oxide: Fe2O3
0.2–0.7% magnesium oxide: MgO
0.5–1.5% calcium oxide: CaO
3–5% loss on ignition (chemical / combined water)[3]

Sources and production

Perlite is a non-renewable resource. The world reserves of perlite are estimated at 700 million tonnes.

The confirmed resources of perlite existing in Armenia amount to 150 million m3, whereas the total amount of projected resources reaches up to 3 billion m3.
Considering specific density of 1.1 ton/m3 confirmed reserves in Armenia amount to 136 million tons.

Other reported reserves are: Greece – 120 million tonnes, Turkey, USA and Hungary – about 49-57 million tonnes.

Perlite world production, led by China, Turkey, Greece, USA, Armenia and Hungary, summed up to 4.6 million tonnes in 2018.

Perlites are small pebbles of natural glass which contain a small amount of occluded water, and are found in volcanic deposits.
When smashed and softened by heat, the water vaporizes, leaving behind enlarged hollow spheres.
These are again smashed, and give a filter aid of very irregularly shaped particles whose bulk density ranges 0.05–0.10 g/mL (3–6 lb/ft3).
This bulk density is between one-tenth and one-fifth of many bleaching clays.

As with other filter aids, be prudent and make a full-scale trial in working conditions to assess the full value—economic and technical—of any perlite grade chosen.

Uses
Because of its low density and relatively low price (about US$50 per tonne of unexpanded perlite), many commercial applications for perlite have developed.

Construction and manufacturing
In the construction and manufacturing fields, it is used in lightweight plasters, concrete and mortar, insulation and ceiling tiles.
Perlite may also be used to build composite materials that are sandwich-structured or to create syntactic foam.

Perlite filters are fairly commonplace in filtering beer before it is bottled.

Small quantities of perlite are also used in foundries, cryogenic insulation, and ceramics (as a clay additive).
Perlite is also used by the explosives industry.

Aquatic filtration
Perlite is currently used in commercial pool filtration technology, as a replacement to diatomaceous earth filters.
Perlite is an excellent filtration aid and is used extensively as an alternative to diatomaceous earth.
The popularity of perlite usage as a filter medium is growing considerably worldwide.
Several products exist in the market to provide perlite based filtration.
Several perlite filters and perlite media have met NSF-50 approval (Aquify PMF Series and AquaPerl) , which standardizes water quality and technology safety and performance.
Perlite can be safely disposed of through existing sewage systems, although some pool operators choose to separate the perlite using settling tanks or screening systems to be disposed of separately.

Biotechnology
Due to thermal and mechanical stability, non-toxicity, and high resistance against microbial attacks and organic solvents, perlite is widely used in biotechnological applications.
Perlite was found to be an excellent support for immobilization of biocatalysts such as enzymes for bioremediation and sensing applications.

Agriculture
In horticulture, perlite can be used as a soil amendment or alone as a medium for hydroponics or for starting cuttings.
When used as an amendment, it has high permeability and low water retention and helps prevent soil compaction.

Cosmetics
Perlite is used in cosmetics as an absorbent and mechanical exfoliant.

Estimated perlite consumption by application
Fraction   Use
53%   building construction products
14%   horticultural aggregate
14%   fillers
8%   filter aid
11%   other

What is Perlite?
Perlite is a volcanic glass that is heated to 1,600 degrees F. (871 C.)
whereupon it pops much like popcorn and expands to 13 times its former size, resulting in an incredibly lightweight material.
In fact, the end product weighs only 5 to 8 pounds per cubic foot (2 k. per 28 L.).
The super heated perlite is comprised of tiny air compartments.
Under a microscope, perlite is revealed as being covered with many tiny cells that absorb moisture on the exterior of the particle, not inside, which makes it particularly useful in facilitating moisture to plant roots.
While both perlite and vermiculite aid in water retention, perlite is the more porous and tends to allow water to drain much more readily than vermiculite.
As such, it is a more suitable addition to soils utilized with plants that do not require very moist media, such as cactus soils, or for plants which generally thrive in well-draining soil.

Perlite is a form of volcanic glass (SiO2) that is mined all over the world. Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. It is an industrial mineral and a commercial product useful for its low density after processing.

Perlite is mined using open pit methods such as ripping or blasting, or both. If the perlite is soft and friable, brecciated or extensively jointed, ripping is employed with significant cost savings. Blasting is required where perlite cannot be readily broken using rippers, but care must be taken to achieve fragmentation without production of excessive fines or oversized material.

Horticultural Perlite
While both perlite and vermiculite aid in water retention, perlite is the more porous and tends to allow water to drain much more readily than vermiculite. As such, it is a more suitable addition to soils utilized with plants that do not require very moist media, such as cactus soils, or for plants which generally thrive in well-draining soil.

Horticultural perlite is made by exposing perlite to heat, which causes the trace water contained in the perlite to expand, “popping” the perlite like popcorn and expanding it to 13 times its former size, resulting in an incredibly lightweight material. In fact, the end product weighs only 5 to 8 pounds per cubic foot. The superheated perlite is comprised of tiny air compartments.

Under a microscope, perlite is revealed as being covered with many tiny cells that absorb moisture on the exterior of the particle, not inside, which makes it particularly useful in facilitating moisture to plant roots. The result is a very lightweight, white stone-like substance. Perlite is prized for its moisture retention and aeration properties. It is naturally sterile and has a neutral pH.

Expanded Perlite: Description
Expanded perlite is a mineral product obtained by expansion of raw perlite. Perlite is a siliceous glass-like volcanic mineral. It is hard and brittle and expands up to 20 times its original volume depending upon the mineral source.
Raw perlite is milled and expanded by controlled rapid heating, which causes water molecules to escape from the mineral. This causes a popping sound, similar to a popcorn’s pop.
Expanded perlite is a chemically inert, non-toxic, and stable material with excellent thermal, audio, and electrical insulation properties. It is primarily utilized in the construction industry for insulation, in the horticulture industry as soil aggregates, and in the beverage industry for food contact filtration applications.
Physical characteristics of expanded perlite makes it an ideal option for usage for filtration purposes. Perlite filter aids are inert, lightweight, and do not impart any taste or odour when used for filtering liquids. They are highly soluble in organic acids. Thus, perlite filter aids are useful for various industrial filtration purposes.
The European Union recently approved the usage of expanded perlite as an additive in animal feed. Expanded perlite is employed in various industries such as pharmaceuticals, paints & coatings, and chemicals
Consumption of beer, juices, wine, etc. has increased. This is boosting the usage of expanded perlite, since it is used in the processing of beer, juices, and wine. This trend is expected to drive the market for expanded perlite in the near future.

Expanded perlite is used in various products in the personal care industry. It is inert and eco-friendly. Thus, it is useful in cosmetic as well as food-grade products.
Expanded perlite is used as an abrasive in cosmetic products such as soaps, face wash, scrubs, and shower gels. It also used in dental care products such as toothpastes.
The personal care products industry is well developed and has been expanding significantly in Asia Pacific and North America. This provides lucrative opportunities for the expanded perlite market.

What is perlite?
Perlite is a lightweight granular material that’s white in colour. It looks and feels like little bits of polystyrene but is actually made from expanded volcanic glass, heated to 1000°C until it ‘pops’ (like popcorn) to many times its original size. It’s lightweight, sterile, and easy to handle, and is long-lasting. It’s neither alkaline nor acidic.

Perlite’s expanded nature makes it extremely porous, so it can absorb water, but it also improves drainage, so is ideal to mix into compost to ensure water drains freely. Perlite is particularly useful in plant propagation, including taking cuttings and sowing seeds. Other materials that perform similar functions are vermiculite, grit and sharp sand.

Perlite helps aid drainage at the same time as retain water. Therefore you can use it in a number of ways:

Use perlite to aid drainage
Succulents and other plants sensitive to moist soil benefit from having perlite added to the potting compost. The perlite will trap air in the compost and encourage water to drain through, ensuring the plant’s roots will never sit in damp soil. Mix perlite with compost at a ratio of around 1:4. Do this before planting to ensure an even mix.

Use perlite when taking cuttings
Perlite can aid water retention in compost, which can help improve the chances of your cuttings taking root. To do this you need a compost that’s specifically designed for cuttings (with a finer texture and lower nutrient content than general use multi-purpose compost). Mix in perlite at a ratio of 50:50, fill the pots, water thoroughly and then allow the compost mix to drain for several hours before inserting your cuttings.

Cuttings can also be rooted in perlite on its own. Moisten the perlite and fill a polythene bag around a third full. Prepare softwood or semi-ripe cuttings by cutting just below a leaf joint and removing the leaves on the lower half to two-thirds of the cutting. Insert the bare lower part of the shoot into the perlite, fill the bag with air and seal the top. After several weeks, roots should start to form. Once roots are well developed, the cutting can be taken out and potted up in compost.

Use perlite in seed sowing
Mix perlite into seed and cuttings compost at a ratio of 50:50 to create a moist environment perfect for delicate seedling roots. A fine layer of perlite is also excellent for covering seed that needs light to germinate because the perlite lets light through whilst still keeping the seed moist and aiding germination.

Perlite is not a fertilizer, and has no nutritional or microbial value to plants or soil. Its benefits are derived solely from keeping the soil structure loose and light.

What perlite is: an inorganic, non-toxic, lightweight soil amendment.

Also known as expanded pyrite, perlite is a mined volcanic rock that is mixed into many industrial building products for stability, such as masonry construction, loose-fill insulation, cement, and plaster.

ike all other volcanic rocks, perlite is also pretty heavy and dense in its natural form. Perlite typically contains the following ingredients:

70-75% silicon dioxide
Aluminum oxide
Sodium oxide
Potassium oxide
Iron oxide
Magnesium oxide
Calcium oxide
3-5% Water
Since it is a naturally occurring mined mineral, perlite is a nonrenewable resource. The major producers are Greece, US, Turkey, and Japan.

It is a relatively cheap mineral and is often used for industrial purposes like construction and in the manufacture of plasters, masonry, and ceiling tiles.

But of special interest to us here is the use of perlite in gardening and hydroponics.

And for that, the hard mineral glass needs to be processed into the light, white colored, plasticky stuff that resembles styrofoam, confusing many a rookie gardener about its origin and purpose!

The processed perlite that we see in gardening mixes is basically “volcanic popcorn.” That is a very literal description.

Since perlite glass is rich in water, it pops when heated to very high temperatures, exactly like popcorn. So the processed perlite balls are created by crushing natural perlite glass and then baking them in industrial ovens.

To complete the transformation, crushed perlite needs to be heated quickly to 900 degrees Celsius (around 1650 degrees Fahrenheit). The mineral structure is softened by the heat, allowing the water trapped inside to expand into steam in a bid to escape.

The process leads to expansion of the crushed pieces of the mineral. It is not usual for perlite pieces to expand between 7 and 16 times their original size and volume, creating those lightweight faux-styrofoam balls.

The foamy balls have a lot of porous openings inside them and are clean, sterile and generally stable. It can hold its shape with ease in the soil without crumbling.

Significance of Perlite for Gardening
There are several reasons why perlite is such a useful additive to gardens and hydroponic setups. They mainly stem from its unique physical and chemical properties:

Perlite is physically stable and retains its shape even when pressed into the soil.
It has a neutral pH level
It contains no toxic chemicals and is made from naturally occurring compounds found in soil
It is incredibly porous and contains pockets of space inside for air
It can retain some amount of water while allowing the rest to drain away
These properties allow perlite to facilitate two critical processes in soil/hydroponics, which are essential for plant growth:

Aeration
All plant cells need oxygen, even those that are underground. The green parts up top are capable of creating it during photosynthesis.

But down below, the root system has to absorb it from the soil. Aerating the soil allows little pockets of air to remain, which helps with the growth of strong root systems.

Draining
Without water, no living thing can survive. But when it comes to plants, excess water in the soil can lead to drowning.

In this situation, the root system is starved of oxygen, causing eventual death. Proper drainage is crucial to allow empty air spaces to remain in the soil.

Adding perlite to the soil improves its drainage capabilities, as it has excellent filtering and water draining capabilities. The presence of all those pores allows most of the excess water to drain off.

And those air pockets also mean that perlite is great for root systems as well. When the soil gets packed down, the air pockets are lost. But since perlite is a harder mineral, it retains its shape, keeping those air pockets around for the roots.

Perlite vs. Vermiculite
Vermiculite

Perlite is directly comparable to another mineral additive called Vermiculite. Both have overlapping functions and help with soil aeration and seed starting.

Vermiculite also comes from some kind of rocks and expands in the same popcorn fashion like perlite. But vermiculite has a stronger expansion potential.

Perlite has more air porosity than vermiculite, and better drainage effects as well. Vermiculite, on the other hand, retains water much better than perlite.

Perlite is better suited for succulent plants, while vermiculite is better for tropical plants that need more moisture retained in the soil.

They both have their uses, and many experts tend to combine these two minerals in their soil mixes.

Perlite vs. Diatomaceous Earth
Diatomaceous Earth

Diatomaceous earth is also a mineral additive, available in a fine powder form. It is commonly referred to as DE.

Diatomaceous earth is used more for pest control than anything else in gardening. It also has high water retention abilities. But since it is a powder, it doesn’t help much with aeration.

Diatomaceous earth is not really a contender against perlite in any conceivable way. Both additives can be used together, for their respective benefits to the soil.

Pros and Cons of Perlite
Pros
Excellent for aeration of roots
Very stable and inert structure
Helps improve drainage
Cheap and easily available
Useful for hydroponics and gardening
Cons
Finer grades are affected by airflow/winds
Does not retain water
Contains no nutrients
Tends to float in excess water
Give off dust. So wear a mask to protect your exhalation when working with perlite

Perlite is an excavated mineral rock that is mixed with potting soil to help manage aeration and drainage for potted plants. The mineral is light-weight and porous creating air pockets within the soil that alleviate stress on roots. Perlite has been shown to help maximize root growth while lessening stress of drainage management for gardeners with plants kept in containers. Simply mix Perfect Plants Perlite with a multi-purpose potting mix or seed starter before planting. Perfect Plants Perlite comes in a 13×15″ heavy duty, re-sealable bag — perfect for storage or later use.

The lightweight mineral prevents soil from compacting and “suffocating” the roots.
It allows proper aeration of the soil so that excess water and toxins can drain appropriately.
Perlite pieces loosen dense parts of the soil which allow room for roots to expand and absorb essential nutrients.
Since perlite is a mineral it will not decompose and advantageously it carries a neutral pH balance. This means it will match the pH balance of your soil when combined, instead of change it.

Expanded perlite is employed in the filtration & process aid applications in mining, water treatment processes and gas drilling activities. In oil fields, the product has usages in thermal insulation, aeration of soil and as a soil aggregate. Increasing drilling activities coupled with technological progressions will augment the expanded perlite market revenue. The product is used for filtering liquids in food & beverage and pharmaceutical industry as the product has inert nature, no taste, odor or color is imparted. It is recognized as a safe material by food safety regulatory bodies. Favorable trends associated with food & beverage industry is going to catapult the product demand in upcoming years.

The expanded perlite market share may be affected by availability of substitute materials. Various alternatives such as barite, polymeric foam and diatomaceous rock can be used instead of the product in many construction applications. However, in horticulture sector, substitutes such as vermiculite, cellulose, wood chips and peat can be used for performing various applications. T

DRAINAGE
• Perlite Decreases the Risk of Over-Watering Which Lessens the Risk of Root Disease.
• It Assists in Flushing Toxins Away While Holding Water Directly Where Roots Can Access.

AERATION
• Perlite Does Not Compact in Soil and Allows Roots to Expand to Their Full Potential.
• Perlite Will Regulate Soil Conditions During Weather Extremes.

SUSTAINABILITY
• Perlite Does Not Decompose Making it a Suitable Match for Container Plants.
• Although It Has No Nutritional Value, The Porous Nature of Perlite Can Hold Nutrients in Place for Roots to Absorb.

How perlite is made?
A natural volcanic glass, perlite is typically made from the hydration of obsidian. The chemical made up is seventy to seventy-five percent silica or silicon dioxide; the remaining twenty to twenty-five percent is a mix of aluminum oxide (Al2O3), oxides of sodium, potassium, iron, magnesium, and calcium, and moisture (1).

To create the perlite we are familiar with, the gray to black obsidian rock is mined, crushed into smaller fragments, and then heated to very high temperatures. Once temperatures reach 850-900 ℃ the perlite becomes soft. Water trapped inside the rock vaporizes and tries to escape, expanding the rock to more than 10 times its original volume and changing the color or perlite to white. An extremely similar process to making popcorn.

The resulting expanded perlite is a lightweight material full of tiny little air pockets; it is clean, sterile, and resists compaction. The pockets on the outside absorb water, blocking moisture from entering into the center of the perlite pieces.

Gardening: Perlite can be added to soilless mixes to improve drainage and aeration, providing more oxygen to plant roots. It is also added to gardens as a soil additive to improve soil structure. Perlite also helps reduce soil compaction in clay soils. It is used as a standalone product to germinate seeds, root cuttings, and anchor/support root systems in hydroponic gardening setups. Epsoma is a great option for perlite and other gardening needs. Purchase it on Amazon here.
Construction: Perlite is used as loose fill material in hollow concrete blocks or masonry walls for insulation.
Filtration: Perlite is increasingly being used to filter solids out of liquids in many applications. It is used to filter beer before it’s bottled to remove sediment and is used to filter stormwater runoff from roads and highways.
Manufacturing: Perlite is also used as an ingredient in lightweight concrete and plasters, ceiling tiles, and acoustical sprays to name a few.
Types of perlite
After heating and expansion, horticultural perlite is separated into four different grades based upon the particle size: super coarse, coarse, medium, and fine grade.

Super coarse perlite has particles ranging in size between ¼ and 3/32” with a water holding capacity of 19%. Creates the best porosity for drainage and aeration but isn’t as popular in gardening because of the particle size.
Coarse perlite ranges in size between 3/16 and 3/64”, with a 34% water holding capacity. Considered an all-purpose grade it is a good balance of drainage and water holding capacity. Due to its size, it doesn’t blend well with garden soil but makes a great media for succulents and orchids.
Medium grade perlite is a middle ground between the coarse and fine grades ranging in size between ⅛” and 1/32”. It has a 46% water holding capacity and is best to use alone as growing media for potted plants and potted seedlings or as an ingredient in potting mixes with other components.
Fine grade perlite has the smallest particle size, with pieces between 1/16 and 1/128”. With a water holding capacity of 52%, it works well for rooting cuttings and starting seeds.
Pros and cons for gardening use
As with so many other products, perlite has both its advantages and disadvantages as a growing media. In this case, the advantages far outweigh the downfalls boosting its popularity in the horticulture industry.

Pros:
Its sterile nature makes it highly suitable for starting seeds. There is little risk of root rot or damping off (2).
Naturally contains minerals needed for plant growth.
A non-toxic substance that doesn’t require rinsing like some other growing media does prior to use.
Neutral pH doesn’t need to be adjusted, nor will it adjust the overall pH when mixed with other components.
It can be used alone or mixed with other media to create potting mixes.
Great for seedling germination or plant propagation as the particles allow for plants to be pulled from the perlite without damage to the root systems when it’s time for transplanting.
Reusable year after year since it doesn’t decompose.
Low-cost option, perlite is cheaper than sand per cubic foot, costing about $4 or $5 per cubic foot.
Easily available and simple to manufacture.
Cons:
Water can drain away quickly. Perlite holds water in the nooks found on its large surface area but since it’s made of amorphous volcanic glass it doesn’t hold it tightly.
Being so lightweight, perlite can be blown away and tends to float in excess water.
Nonrenewable resource. Although more readily available than peat moss, it isn’t considered renewable like coconut coir.
Dust can create respiratory problems and eye irritation. When working with perlite make sure to take precautions by wearing goggles and a mask to reduce dust exposure.

Perlite is one of nature’s most versatile and efficient minerals.
Its unique characteristics of being lightweight, sterile, insulating, and fireproof make it an excellent choice for such diverse applications as:

CONSTRUCTION
FILTRATION
HORTICULTURE
INDUSTRIAL
INSULATION
ENVIRONMENTAL

Perlite in Construction
Perlite is a versatile and sustainable mineral that is mined and processed with a negligible impact on the environment. And the green community recognizes perlite-enhanced products—like lightweight insulating concrete roof decks—as a high-performance solution drawn from a natural material of nearly unlimited supply throughout the world.

Construction Uses
Lightweight concrete & plaster
Loose fill & slab insulation
Fireproofing sprays
Chimney fill
Interstitial floors
Acoustical sprays & ceiling tiles
Texturizing agent
Fire-rated door cores
Blast panels
Tile, mortar and grout

Research claims that more than 50 percent of expanded perlite worldwide is used by the construction industry.
Perlite plays an important role in a wide variety of construction-related uses including: as an aggregate in lightweight insulating concrete and plaster; as a loose fill insulation material for concrete masonry blocks, cavity walls, in residential homes; and in a variety of specialty applications including fireproofing sprays, chimney fills, interstitial floors, acoustical sprays, etc

LIGHTWEIGHT INSULATING CONCRETE
Lightweight Perlite Insulating Concrete offers architects, engineers, and building owners several important benefits:

Superior thermal performance with high insulating values
Non-combustible with superior fire ratings
Lightweight and durable
Smooth monolithic slope-to-drain surface
Roofing material can be nailed or glued
Meets UL and FM wind uplift criteria
An innovative hybrid technology improves cellular concrete
Realize savings in time, labor, and materials

Perlite for Horticulture
When perlite ore is expanded or “popped” by rapid, controlled heating, it expands up to 15 times its original volume and takes on a foam-like cellular appearance – essentially clusters of microscopic glass bubbles, creating a porous structure. This physical transformation makes expanded perlite an extremely effective aggregate for use in horticultural growing mixes – or, by itself, as a medium in hydroponic growing and as a rooting medium

The primary role of expanded perlite in soilless growing mixes is aeration when added to peat moss, composts, coir and other water-holding aggregates. The porous surface of expanded perlite provides room alternately for both air and water in the mixes – each needed for vigorous root growth. Different sizes of perlite are produced for this purpose, offering growers various amounts of air space after drainage. Usage rates by volume vary from 5% to 40% for potting mixes, and as high as 75% to 100% in green roofs and hydroponics applications. Perlite use is increasing in agricultural and turf grass applications to break up compacted soils and retain water in dry climates.

THE BENEFITS OF PERLITE AS INSULATION
When perlite ore is expanded by exposure to rapid, controlled heating, it grows up to 20 times its original volume and takes on a foam-like cellular internal structure — essentially clusters of microscopic glass bubbles. This physical transformation makes expanded perlite an extremely efficient, low density insulator.

As detailed below, perlite is inorganic and non-combustable, and the loose-flowing nature of expanded perlite is ideal for filling odd-shaped spaces.

MASONRY FILL PERLITE
Expanded perlite provides a quick, inexpensive and permanent method for insulating masonry walls. Depending upon design conditions, reductions in heat transmission of 50 percent or more can be obtained when perlite loose fill is used in the hollow cores of concrete block or cavity type masonry walls. Perlite is a non-combustible, industrial mineral yielding superior dynamic thermal performance.

CRYOGENIC/HIGH TEMPERATURE INSULATION
Super-cold cryogenic fluids such as hydrogen and helium are normally stored in double-walled vessels with perlite-filled annular spaces.

OTHER INSULATION APPLICATIONS
Perlite insulation is an inorganic product that does not support combustion, or rot, nor does it provide a habitat for rodents. It is ideal for use under concrete slabs, in chimneys and in high-temperature applications such as pizza ovens and rocket stoves.

Perlite for Filtration
The physical character of expanded perlite bubbles lends itself to a variety of special purposes – including use as a filter aid separating small solid particles from liquids

Lightweight expanded perlite bubble structures are milled and classified using strictly defined processes to produce perlite filter aids with specific flow characteristics. The various grades utilize the jagged interlocking structures (see image right) to create billions of microscopic channels between the filter aid particles to produce optimum flow rates and clarification abilities for a wide variety of applications.

THE BENEFITS OF PERLITE AS A FILTER AID
Perlite filter aids are lightweight, inert, impart no taste or odor to liquids being filtered, and are virtually insoluble in mineral and organic acids at all temperatures. Solubility in strong alkaline solutions varies depending on temperature and contact time.

Without using a filter aid the solid particles in the liquid will soon accumulate on filtering surfaces and block them.

A perlite filter aid makes a filtering layer (cake) that transfers the actual filtering from the septum to the whole mass of filter aid. Filtration occurs in the tiny pores formed by the fine particles of filter aid.

Volume-Based Pre-coat Filtration
Perlite filter aids provide users with a lightweight material choice. Perlite filter aid grades provide the user with a density advantage from 20 to 50% over other types of filter aids. Perlite filter aid dry density ranges from 100 to 200 kg/m3 (6 to 12 lb/ft3), and the filter cake density range is 100 to 270 kg/m3 (7 to 17 lb/ft3). In contrast, other filtration materials produce equal performance filter cakes in the range of 230 to 420 kg/m3 (15 to 25 lb/ft3).

Expanded perlite provides larger volumes with low bulk density compared to other filter aids. Experience in a variety of applications has shown that most filter aid users can economically switch to perlite from other pre-coat filter aids without sacrificing performance.

Usable With Standard Equipment
Perlite filter aids can be used with either pressure or vacuum filtration equipment. Perlite generally replaces other filter aids on a one-to-one volume basis – for example; a cubic measure of perlite will replace the same volume of other filter aids. Selection of the optimum grade and dosage may require plant or laboratory filtration tests.

The higher flow grades are especially applicable to use with highly viscous liquids such as syrup, resins or gelatinous slurries. Productivity, clarity and flow rates may be increased through the use of perlite filter aid grades. These traits are accomplished during the liquid’s path through the channels created by the jagged, interlocking particles.

Easy Cake Release
Additional benefits of perlite filter aids come at the end of the filter cycle. Perlite filter cakes remain porous and do not compact. Filter cakes built up under pressure release easier when perlite is used. This release facilitates cleaning, potentially reduces manpower requirements, and increases productivity. The lower weight of perlite filter cakes may also reduce disposal costs.

Inert Nature of Perlite
Perlite filter aids are both sterile and inert and are used for filtering liquids in the beverage, food and pharmaceutical industries. No tastes, colors or odors are imparted, and, subject to meeting the standards listed in the Food Chemicals Codex (published by the United States’ National Academy of Sciences), are deemed safe for their intended use. Note: The Food Chemicals Codex is regarded as a source of information on the quality and purity of food grade substances, and is regarded as authoritative by many government agencies throughout the world.

Approval for the use of perlite as an additive in animal feeds was recently extended in the European Union. Generally, spent filter aid cakes from wineries, breweries or other food-related industries may be added to animal feed. Such practices reduce the environmental footprint of those industries as well as reducing disposal costs for the used material. Approval for this application in the United States comes from the Association of American Feed Control Officials (AAFCO).

USE BY INDUSTRY:
Perlite filter aids have gained acceptance in almost every industry concerned with the separation of liquids and solids, and even gasses and solids. The following list, although not all-inclusive, gives an indication of the many applications where perlite filter aids are being utilized due to their low density, availability, performance, economy and environmental footprint:

Food Processing:
juices
beers
wines
sweeteners
vegetable oils
wastewater treatment

Pharmaceuticals:
enzymes
antibiotics
Epsom salt

Industrial:
water treatment
sizings
oil & solvent recovery
greases
Chemicals:
inorganic & organic chemicals
resins
polymers
brine
adhesives
fertilizers
waste disposal

Paint & Coatings:
waxes
oils
varnish
gums
shellac
wastewater treatment
Environmental:
stormwater filtration
ecology embankments
media filter drains

PERLITE IN SOUND INSULATION:

When it comes to noise protection in buildings, both sound-absorbing and sound-blocking (or soundproofing) materials come to mind.
When it comes to noise protection in buildings, both sound-absorbing and sound-blocking (or soundproong) materials come to mind.
Each offers unique properties that make them suitable for specic applications.

Processes that Govern the Absorption of Sound by Acoustic Materials
First, in porous materials, sound energy is transformed into heat by the viscous forces at work when sound propagates through materials.
Second, sound is dissipated by frictional forces when acoustic materials are set into vibration by the incident sounds.

Types of Noise
Airborne Noise – When airborne noise strikes a floor or ceiling, the surface is set to vibration by the fluctuating pressure of the sound waves. This vibration is what radiates sound into the air on the other side.
Impact Noise – Impact noise is caused by an object striking or sliding on a floor, such as footsteps, moving furniture or a door slamming. It can also be caused by an appliance, such as a dishwasher or shower, which transmits its vibration to the building structure.

How Perlite Works as a Sound Absorption/ Blocking Material
The characteristic cellular structure of perlite and the successive air compartments hinder the propagation of sound waves, rendering it an ideal filler for sound-blocking and sound-absorbing applications.
When used as a filler, sound waves can be consumed and absorbed by multiple levels due to the combination of an interconnected pore structure and cavity resonance sound absorption structure, resulting in a higher performance, sound absorption/blocking material

Perlite in Sound Insulation Applications

Applications
The versatile nature of expanded perlite allows it to be used in the manufacturing process of both sound-blocking and sound-absorbing products globally.

Sound-Absorbing Perlite-Based Products –
Expanded perlite is traditionally used as a primary constituent in the production of lightweight sound insulating panels and ceiling tiles.
The intrinsic porous nature of lightweight expanded perlite absorbs sound waves and reduces the reverberation time.
Another option is the use of perlite as filler in spray-on absorbers. During spraying, perlite is mixed with a binding agent and water to produce a soft lightweight material with a coarse surface texture and high sound absorption characteristics.
In one application, spray-on absorber containing perlite achieved a NRC value of 0.70.

Sound-Blocking Perlite Products –
Expanded perlite is an essential constituent of perlite lightweight concrete. Densities greater than 1,000 kg/m3 (62 lb/ft3) offer a higher degree of sound-blocking.
By varying the amount of perlite used in the mixture, one can achieve a balance between the weight of the overall structure, and the need for sound blocking levels of sound insulation.
For example, the airborne sound insulation per Approved Document E–UK for new dwellings is 45 DnTw + Ctr dB. By definition, this is the weighted Sound Reduction Index with the addition of a low frequency sound correction factor (Ctr).
Perlite manufacturers have developed a variety of performance

Most building codes now require oors, external walls, and intertenancy walls to comply with varying solutions for harnessing the benets of perlite lightweight concrete to meet the stringent local building code requirements.
For example:

Perlite Lightweight Concrete Floor Sound-Blocking Solutions –
Perlite lightweight concrete oor screed is used to reduce unwanted sound transfer between floors in a multilevel building. A typical perlite lightweight concrete oor installation with an oven dry density of 1,300 kg/m³, at a thickness of 50 mm (2 in.) applied directly (bonded) on 200 mm (8 in.)
thick reinforced cement concrete (RCC) slab achieves an airborne sound rating of: Rw (C; Ctr) = 56,1 (-2 ;-6) dB.

Perlite Lightweight Concrete In-Fill Partition Wall Systems –
A sustainable drywall partition developed using perlite lightweight concrete in-fill at a density of 1,000 kg/m³ gives this partition wall system a minimum 4-hour fire rating and complies to 45 DnTw +
Ctr dB for intertenancy walls (Figure 3). is is achieved with a thickness of 200mm (8 in.)
illustrates the sound performance index of the perlitebased partition system with varying thicknesses.

Further Benets of Perlite When Used as a Filler in Construction Applications:
Excellent thermal insulation
Lightweight
Safe to handle; non-toxic, inert and inorganic material
Fireproof and non-combustible
Resistance from corrosion from most chemicals
Cost eective
Low environmental impact

The Water-Holding Capacity of Perlite
The natural size and unique structure of expanded perlite makes an ideal framework to hold water.

Perlite holds water in one of three ways: in between individual grains, in channels leading to the cores of the grains and on the highly irregular surfaces of each particle.
The surface of perlite is made up of the outer convex shells of glass bubbles and concave openings, so each particle can soak up a good amount of water.
While perlite can hold a variety of liquids, many of the actual applications involve water, so it is used here to illustrate and simplify this process.

Gradation Affects Capacity
The amount of water taken up by particles of perlite is largely dependent on particle sizes. Just as fine, clay-rich soil holds more moisture than coarse, sandy soil, different particle size distributions of expanded perlite hold more moisture than others

Moisture Retention and Release
Some applications need water or other liquids to remain in the perlite, while other applications benet from the release or drainage that perlite provides.
The perlite industry provides both coarse grades that drain liquid easily, and fine grades with lower porosity that retain more water for longer periods of time.

There is a method used by the greenhouse and nursery industry to visualize moisture retention and release in growing media.
In this method, growing media is saturated with water and allowed to drain by gravity alone to determine its maximum water-holding capacity.
Then, small increments of pressure are added to simulate the effect of suction of moisture and nutrients caused by plant roots in soil.
The resulting curves in the chart demonstrate how dierent sizes of perlite grains respond differently to increasing amounts of pressure.
The maximum water-holding capacity for various grades of perlite at gravity pressure are summarized.
Professional growers in different regions take advantage of these differences to achieve optimal moisture levels for their climate.
A dry environment requires more water retention, while a cool and damp environment would demand a grade with higher drainage rates.
Through the years, the industry has gathered information on the needs of these growers and provides them with the best particle size distribution and density materials.

Wicking Ability and Drainage Rate
Two more factors affecting perlite’s water-holding capacity are its miraculous ability to soak up moisture against the opposing force of gravity, and secondly, its ability to let excess moisture drain out to just the right level for plant roots.
Water mobility in perlite is excellent regardless of initial moisture levels due to relatively fast-acting capillary action.

Water-holding Applications
Many applications take advantage of perlite’s moistureholding capacity. Among the most successful are:
• Soilless growing media
• Seed starting
• Plant propagation
• Hydroponic growing
• Vegetated roofs
• Stormwater bioltration
• Turf underlayment
• Native soil amendment

The Water-Holding Capacity of Perlite

In the arid Middle East, perlite has been used with success as an absorbent layer between the root zone and desert sand.
Reports are that less than 50% of the normal water usage is needed to maintain the quality of sod and other plantings.
In a separate example, farmers in the United States have begun adding perlite to their elds to improve workability, air and water-holding capacity to their soil.
Perlite helps combat compaction in native soils and helps increase the level of healthy biological activity by increasing oxygen in the root zone.

As a general rule, clay-rich soils need coarser grade perlite to provide good drainage while medium grade perlite offers a balance between air and water-holding capacity.
Fine grades will help with moisture retention in fast draining sandy soils.

Perlite, Water Conservation & Sustainability
Perlite has an important role to play in conserving the world’s fresh-water resources.
Intensive greenhouse and container growing, produces greater yields per acre, and is oen a more ecient use of water than field growing.
Even in very arid regions, perlite can be used as a growing medium to feed the local population using limited resources

As opposed to other growing media, perlite readily gives up its water to plants, meaning plants expend less energy extracting water from growth substrates, and put more energy into root and vegetative development.
And since perlite is derived from natural sources, growing media containing perlite can be composted or recycled after use and won’t add to the global landfill crisis.
There are endless possibilities of how this versatile mineral can be used to store and release water, nutrients and other liquids

Solutions to Weighty Problems
The current, eco-friendly trend of designing commercial buildings with rooftop gardens has put a premium on the use of expanded, volcanic perlite in making lightweight soils for these structures. Regular, wetted soil can tip the scales at well over 100 pounds a cubic foot — while a perlite/peat moss mixture will weigh a mere 40 pounds while providing the long acknowledged advantages of superior air porosity and water-holding capacity for plants.
Rising fuel costs have also forced nurserymen to acknowledge the lightweight advantages ofperlite-based soil mixes when shipping plants across the country. All signs are for continued growth in this valuable industrial mineral.

The System
Horticultural perlite and peat moss mixtures are used by professional growers for many reasons. They form a lightweight planting mix for rooftop gardens and other areas where normal soil use presents a weight problem.
Advantages
• Lightweight—Horticultural perlite and peat moss, fully watered, weigh only 40 lbs. per cubic foot. Soil fully watered weighs 100 to 125 lbs. You can reduce planter weight by at least 60% by specifying horticultural perlite and peat moss as a growing mix.
• Long-Lasting Economy—Horticultural perlite is an expanded volcanic mineral.
Unlike organic matter, perlite will not deteriorate.

• Retains Water and Plant Food—Horticultural perlite will retain three to four times its weight in water and will not become soggy.
At the same time, it increases the nutrient and air-holding capacity of the planting mix.
• Chemically Inert—Horticultural perlite has an essentially neutral pH and will not noticeably change the alkalinity or acidity of a planting mix.
The planters themselves can be constructed of reinforced concrete.
To further reduce weight, use of perlite aggregate concrete will reduce planter weight at least 75%.
Pre-formed fiberglass planters may also be used to save weight. Recommended planter depths are indicated in diagram at bottom of sheet.
Rooftop Garden on the Marriott Hotel Parking Garage

Application
Suggested mix for nurserymen who prefer some soil in their planter mix, the following proportions have been suggested for one cubic yard:
• 1/3 cubic yard horticultural perlite
• 1/3 cubic yard coarse peat moss

Perlite Solutions for the Green Building Industry
Perlite is a natural fit for green building initiatives and certifications

Green building solutions are increasingly called for to balance the world’s need for more human habitation with limited resources.
It is said that buildings in the United States use one-third of the total energy consumed, two-thirds of the electricity, one-eighth of the water, as well as impacting the land.
Green building initiatives consider a building’s energy use, water use, indoor environmental quality, and the materials used in its construction.
In addition, it assesses the effects a building has on its site and uses this information to further sustainable solutions throughout the entire life cycle of a building.
Perlite’s versatility and usefulness have an essential role to play in contributing to dierent types of green building initiatives.
Multiple Attribute ratings programs such as LEED (USGBC) and new building standards such as the National Green Building Standard (IgCC), encourage the use of materials and practices that prioritize more energy efficient systems and environmentally friendly materials.

BENEFITS OF PERLITE IN CONSTRUCTIONS AND BUILDINGS:
■ 100% natural; produced without harmful chemicals
■ Will not o-gas
■ Inert and pH balanced
■ Will not leach chemicals into the environment
■ Is an excellent insulator
■ Lightens denser materials like concrete and soil
■ Promotes plant growth; reduces irrigation demand
■ Can often be locally sourced
■ Provides stormwater detention and ltration
■ Is durable and has long-lasting benets

Thermal Performance
Perlite is an excellent insulator and is therefore prized for its contribution to Optimized Energy Efficiency and ermal Comfort.
Perlite is applied both as loose fill insulation in cavity walls and below floors, and as an alternative to sand in lightweight insulating concrete roof designs.
Further points may be awarded for Low Emitting Materials since perlite is hypo-allergenic and does not off-gas volatile organic compounds.

Water Efficiency
Another area perlite contributes to LEED certication is in Indoor & Outdoor Water Use Reduction.
Horticultural perlite can store trace amounts of irrigation or rainwater for later release and uptake by planting and vegetation

Perlite in Lightweight Manufactured Stone
Lightweight, incombustible, and compatible with many other materials, expanded perlite offers significant advantages when used in the making of masonry veneer products.

Decorative, fireproof, lightweight, and insulating manufactured stone can be made with expanded perlite.

The physical characteristics of expanded perlite lend themselves to a variety of special purposes—including use as a component of lightweight manufactured stone. For a detailed explanation of perlite expansion, see info sheet: Why Perlite Works.
Expanded perlite is widely seen as an economical way to lighten concrete and plaster. But did you know it can also be used to enhance manufactured stone and masonry veneer products?
Manufactured stone (also known as simulated stone) made with perlite, is fire resistant, weighs as little as one third as much as generic versions, and above all—is attractive!

Advantages of Perlite Manufactured Stone
Perlite manufactured stone products are lightweight thereby reducing strain on workers accustomed to handling denser materials like stone. They are less energy intensive to ship, and offer added insulating benefits resulting from the bubbles of trapped air that constitute expanded perlite.
Perlite can be used in place of materials that are denser, more costly, or harder to come by, or simply to lend alternative textural or visual appeal.
Manufactured stone products are excellent for hiding irregular wall surfaces and may be used in new construction, remodeling and in exterior applications, depending upon the binder used.

Mix Compounds
Perlite concrete and plaster aggregates conforming to ASTM specifications are commonly used in the making of manufactured stone. Binders and other components of perlite manufactured stone usually include Type I or Type III Portland cement, gypsum, lime, clay and castable or other resins. Other additions may include sand, pumice or shale, coloring agents, silicates, alkali resistant fiberglass or polypropylene shorts.
Mix designs for perlite manufactured stone products range based on application.
Mixing is accomplished with ribbon, plaster or other mixers having low shear action. Paddle type and size should be chosen for the lowest shear rate.

Stone
Among the applications for lightweight perlite manufactured stone are exterior siding, fireplace logs, masonry blocks; and brick and stone for decorative exterior and interior applications.

PERLITE CONCRETE
Perlite Concrete Offers Many Advantages Beyond Its Light Weight.
This product guide contains various mix designs for lightweight concrete, utilizing perlite as the primary aggregate, which may be used as stated or as a starting point for your own custom mixes.
Perlite lightweight concrete is used in many different applications. These include lightweight tile mortar, statuary, decorative stone, gas-fireplace logs and floor fills.
Perlite concrete, while not usually suited for structural or load bearing uses, offers many advantages beyond its light weight. Perlite concrete provides better noise reduction and thermal insulating properties than conventional concrete. Generally speaking, the lighter the weight, the greater the insulative properties.
Other Perlite Concrete Applications
■ Chimney Lining
■ Sound/Firewalls
■ Pool Bases
■ Tank Insulation General Considerations
■ The addition of sand to a perlite/cement mix will increase the density and compressive strength.
■ The addition of medium-weight aggregate (pumice or Perlite cultured stone and gas fireplace logs expanded shale) will increase the density and compressive strength.
■ The addition of fibers increases the tensile and flexural strength of perlite concrete, thereby reducing shrink cracking.
■ The addition of air entraining agents reduce the density and compressive strength of the mix, and improves freeze/thaw performance.
■ A range of aggregate size is desirable for increasing compressive strength. Super-plasticizers and water reducers can also be used to increase strength.
■ Finer aggregate particles can be used to produce smoother finishes.

Insulating Underground Pipe and Ducting with
Perlite Insulating Concrete

Lightweight perlite insulating concrete can play a multiple role in underground pipe and duct installations. In addition to providing quality thermal insulation, perlite concrete insulation can also serve as a supporting envelope. This latter advantage is of special importance when pipe or ducts are laid under roadways, parking lots or other areas subject to traffic. Perlite concrete pipe insulation provides a monolithic (seamless) insulation for the length of a pipe or duct. Additionally, perlite insulating concrete is permanent, fire proof, rot proof and vermin proof.

Stable or Compacted Soils

Where there is stable or compacted soil, pipe or ducting may be supported on precast perlite concrete support blocks in the bottom of a trench and a perlite concrete cover poured into the trench area. Depth of concrete cover and pipe spacing will depend on the size of pipe or duct to be insulated as well as operating temperatures. The perlite cover should be waterproofed by encasing the perlite concrete with a polyvinyl chloride (PVC) membrane. Internal vent drain lines may be required. If operating temperatures are in excess of 800°F (427°C) Aluminite cement should be employed. Prior to pouring concrete, pipe and ducts should be wrapped with a parting material such as wax coated corrugated paper to prevent the perlite concrete from adhering to the pipe and to permit free longitudal movement of the pipe as a result of temperature changes.

Disturbed or Loose Soils

When disturbed soils are encountered in the trench area, a perlite concrete base pad should be poured first. Precast perlite concrete support blocks are then placed on top of the base pad and the installation proceeds as for installations in compacted soils.

Expansion Loops or Ells

Expansion loops and ells must be carefully designed as there will be pipe or duct movement in the perlite concrete insulation as a result of temperature changes.
Depending on the design, metal pan blockouts can be used to isolate the pipe or ducts from the insulation in those areas where there is excessive movement.
Double wraps of 1-1/2 inch (4 cm) foil faced fiberglass may also be used to accommodate pipe movement at elbows, expansion loops, expansion “Z”s and U-bends.

Heavy Traffic Areas

Where there is heavy traffic loading on the soil above an insulated pipe as when running pipe under parking lots or highways, the designer should take this loading into account.

Perlite Aggregate for Lightweight Tile Mortars

The widespread use of lightweight perlite aggregate replacing sand in tile mortars is easily understood when one studies the advantages that perlite has to offer. In addition to cost savings made possible by the reduction of labor fatigue, tile contractors are able to give their customers better installations.

ADVANTAGES OF LIGHTWEIGHT PERLITE AGGREGATE
1.   lighter in weight
2.   easer to handle and mix
3.   easier to transport
4.   less tiring to work with
5.   clean and convenient to measure as perlite is supplied in bags
6.   eliminates messy piles and waste of aggregate; unused portions are easily removed and can be used elsewhere
7.   lightweight perlite aggregated tile mortars impose less dead load on structural members
8.   since the perlite aggregate is bagged dry, thawing out is not necessary in winter as is the case with sand
9.   tile mortars containing lightweight perlite aggregate are:
a.   light in weight
b.   heat and cold insulating
c.   crack resistant
d.   vermin proof
e.   resilient
f.   uniform quality
g.   fireproof
h.   sound insulating
i.   moisture proof
j.   easy to use
k.   bondable

MORTAR INGREDIENTS
1.   Cement: Portland cement, ASTM C-150, Type I (White Portland cement may be used.)
2.   Perlite Aggregate: Perlite aggregates used for lightweight tile mortars shall weigh not less than 7 ½ nor more than 15 lbs. per cu. ft. and particle gradation shall conform to ASTM Specification C-35.
3.   Lime: Hydrated, ASTM C-206 or C-207, Type S.
4.   Water: Potable

ACCEPTED MIX PROPORATIONS FOR PERLITE TILE MORTARS
Always measure ingredients for tile mortars in the proportions of 12 qt. Buckets. A bucket ratio mix is easier to handle as well as being more accurate.

There are several accepted mix proportions in use by tile setters throughout the country.

Thoroughly mix all ingredients dry and then add sufficient water to obtain desired consistency. Avoid use of excessive water.

The mix can be used for both the scratch coat, leveling coats and staling bed, allowing 48 hours for the scratch coat to set up. On a scratched and plumbed wall a softer consistency mortar is required than chat to be floated directly on a steeltex wire mesh or hardness cloth.

APPLICATION
It is recommended that a thin coating of neat Portland cement paste be troweled or brushed over each previously soaked and drained rile before it is installed on a lightweight perlite aggregated mortar bed. This skim coat assures a satisfactory bond.

Trowel cutting of the setting bed both vertically and horizontally is recommended every three or four courses of tile to prevent any possible cracking which may occur.

TILED CEILINGS
Bathroom and kitchen tile ceilings can also be installed with lightweight perlite aggregated tile mortars. It is less tiring to trowel the lightweight mortar on ceilings and much easier to handle.

REMODELING
Tile mortars containing lightweight perlite aggregate are especially suitable for remodeling. The reduced weight of the finished installations places a minimum of stress on old walls and building structure.

Perlite Cement-based Lightweight Insulating Plasters
Fire retardant, and extremely lightweight—weighing Perlite cement plaster is thermal and sound insulating, approximately 60% less than ordinary sand plaster

Perlite Cement-based Plaster
Perlite cement-based plaster can be used on new or remodel work, as a basecoat for stucco finishes, and as a substrate for ceramic tile or masonry veneer.
It can be applied over metal or wire lath, on top of a cementitious bonding or key coat, or directly over other surfaces prepared with an approved liquid bonding agent.

Advantages of Perlite Plaster
■ Lightweight—It weighs up to 60% less than ordinary sand plaster, making it ideal for panelized wall construction.
■ Strong—Resistance to hydration cracking is dramatically increased with the addition of alkaliresistant glass or polypropylene fiber shorts.
■ Insulating—It offers 4x as much thermal transfer insulation as sand plaster, and perlite lightweight concrete has been used successfully in residential construction to reduce noise transfer through walls.
■ Fire Retardant—Up to 4-hour fire protection is achievable with the minimum weight and thickness. fifty (50) fire tested designs have been approved for use by recognized laboratories; it is commonly used in the protection of structural steel columns.
■ Adaptable & Easy to Handle—Perlite is easy to stock and handle on the job site. A typical 4 ft3 (110 L) sack weighs 32 lbs (14.5 kg) making it easy to pour, measure, and mix.
■ Stable & Durable—It will not rot or decay, and has been used in a variety of conditions around the world since 1946.

NOTE: In panelized constructions, where panels are fabricated in a horizontal position, the plaster may be placed monolithically, i.e., poured in one coat and screeded level. When plaster begins to set, but is still sufficiently plastic that it can be manipulated with the tools, it shall be properly floated to provide compaction.

Perlite Cement Plaster

General Considerations
■ The same limitations for Portland cement plaster apply to perlite cement-based plaster.
■ Because of its insulating value, perlite plaster is not recommended over radiant heating panels.
■ Use of alkali-resistant glass or polypropylene fiber shorts is recommended when designing Perlite-based Portland cement mixes.
■ Over monolithic concrete, the thickness of bonding plaster and perlite plaster basecoat shall not exceed 3/8 inch (10 mm) on ceilings and 5/8 inch (16 mm) on walls. If additional thickness is required, self-furred metal lath should first be secured to concrete surfaces.
■ Divide large expanses of plaster with properly installed relief joints. Discontinue reinforcing lath at relief joints.

Cement plaster must be water-cured between 3 – 7 days to reduce contraction and minimize cracking.
■ Use of metal or wire lath typically requires three coats.

Perlite Cement Plaster

INSTALLATION GUIDE
Substrate Preparation
■ All surfaces must be clean, free from dust, oil, or traces of foreign materials or protrusions.
■ The use of rails or spot levels at every (max.) 10 feet (3 meters) is advised to control application thickness.
■ Expansion joints or grooves are recommended to allow for expansion of the plaster.
■ The use of wire mesh is recommended on dissimilar materials (e.g. blockwork and columns).
■ Wetting of substrate is to be done on extremely dry surfaces, but otherwise, stagnant or frequent water flow on substrate surfaces will lead to poor adhesion.
■ Use of spatter dash mechanical key (textured key) or suitable bonding base coat is required on concrete surfaces to improve adhesion. Ideally, the undercoat should be keyed (using a wire scratcher) to improve adhesion of the subsequent coat.

General Mixing & Installation Instructions
■ Place 80% of the required water in the mixer, followed by lime (if used) and cement. Add the remaining water and mix until the slurry is uniform, approximately 1 to 1½ minutes. Add the perlite, and any additional aggregate, and sprinkle in the chopped fibers while the mixer is rotating. Mix thoroughly until a uniform paste is formed. Mixing should not be longer than four (4) minutes.
■ When using a key coat, score surface horizontally to provide adequate mechanical bond for the brown coat. Keep this scratch coat damp for a minimum of 48 hours. The brown coat may be applied immediately after the scratch coat has attained sufficient rigidity to support it. The brown coat should be brought out to proper thickness, rodded level and properly floated to densify, but left sufficiently rough to receive the finish coat.
■ Apply each coat either manually or mechanically in thicknesses ranging from 1/2 inch (12 mm) up to 1-1/4 inches (30 mm).
■ Perlite plaster should be water cured for a minimum of three (3) days subject to ambient temperature. Protect plaster from damage due to impact, overloading or marring of surfaces during curing period.
■ When using expanded metal or wire fabric lath, use no less than three coats. On the first coat, use sufficient material and pressure to solidly fill all openings in the lath.
■ In some cases, a single coat can be used if a suitable bonding surface is provided for adhesion.

PERLITE
PLASTER /PORTLAND CEMENT AND GYPSUM
Perlite is a siliceous volcanic rock containing a small amount of combined water. When crude perlite ore particles are heated to description plasticity, they expand to form countless sealed glassy cells. This accounts for the excellent insulating properties and light weight of expanded perlite.
Perlite plaster consists of a blend of expanded perlite aggregate and neat gypsum or portland cement mixed with water for application by gun or trowel to wall or ceiling surfaces or to metal wire or gypsum lath for structural steel membrane fireproofing.
Mixed with portland cement or gypsum plaster, it is used for lightweight insulating curtain wall construction and stairwell encasement.
Perlite portland cement based plaster can be used on new or PORTLAND remodel work as a base coat for stucco finishes, ceramic tile or masonry veneer.
Perlite portland cement plasters are approved for CEMENT as much as 4-hour fire protection of structural steel columns.
They are ideal for weather exposed structural steel elements requiring fire protection. Sand aggregate can be added to increase compressive strength.
Where desirable all plasters containing portland cement must be applied over metal or wire lath or other suitable surfaces prepared with an approved liquid bonding agent.
Plastering on metal or wire lath is typically three coat work but some building codes allow two coat plastering under certain conditions.
Two coat plastering is most typically used in repair and remodeling operations.
Perlite plaster aggregate mixed with gypsum provides an ideal GYPSUM base coat plaster for interior walls and ceilings and for membrane fireproofing to the underside of floor and roof assemblies, or structural steel members.

FIRE PROTECTION
CURTAIN WALLS
GENERAL PLASTERS

Design of a perlite portland cement curtain wall system having a 4-hour exterior fire rating

• Lightweight — Weighs approximately 60% less than ordinary sand plaster, saving about one ton (907 kg) for every 100 yd 2

advantages

(83.6 rn 2) of material applied 1/2 in. (13 mm) thick.
Insulating — 4 times more resistant to heat transmission than sand plaster . . . permits savings in heating and air conditioning costs . . . conserves energy.
Fire Retardant — Non-combustible and non-toxic provides up to 5-hour fire protection with minimum weight and thickness . more than 50 fire tested designs by recognized laboratories.
Noise Reduction — Reduces sound transmission between partitions.
Adaptable — Packaged in 3 or 4 cubic feet (85 or 1 13 litre) bags in the United States and Canada and in 100 litre bags in most other countries . . . easy to measure, mix and handle job mixing permits proper proportioning to meet different plaster bas„ ed materials specifications.
Durable — Cannot rot or decay strong but not brittle dures freeze-thaw exposure … successfully used on major construction projects since 1946.
Normal limitations for gypsum plaster and portland cement plaster apply.
limitations

Plaster application on any surfaces that have been coated with bituminous compounds is not recommended.
• Perlite gypsum plaster is not recommended over radiant heating panels because of its insulating value.
Long continuous runs of gypsum or portland cement based plaster should be broken to relieve stresses and strain caused by thermal or structural movement.
Over monolithic concrete, the thickness of bonding plaster and perlite„gypsum basecoat shall not exceed 3 / 8 in. (10 mm) on ceilings and 5 1 8 in. (16 mm) on walls. If additional thickness is required to produce desired lines or surfaces, self • furred metal lath shall be secured to concrete surfaces.
Gypsum plaster when used with perlite should be milled and set “for use with lightweight aggregates.”
Where perlite-gypsum plaster with smooth troweled finish is to be applied over expanded metal or wire lath, it is recommended that perlite fines be added to the finish coat mix.

PERLITE PORTLAND CEMENT PLASTER
PART 1. GENERAL

.01 SCOPE
The plastering contractor shàll furnish all labor, materials, equipment and supervision for installing the perlite-portland cement based plaster in accordance with the- recommendations as published by Perlite lnstitute, Inc., applicable drawings, and contract documents. Apply all perlite portland cement plaster to thickness indicated on the drawings and apply in two or three coats as required by building coda

1.02 WORK BY OTHERS
Furring arid lathing, sprayed fiber mixtures, decorative finishes, wall reinforcement, gypsum plaster, gypsum wallboard or additional material shall be provided by others.

PART 2. PRODUCTS

2.01 IDENTIFICATION AND MARKINGS.
Identify packaged materials with manufacturers’ brand name. Provide similar information in the shipping advices accompanying the shipment of bulk materials. 2.02 DELIVERY AND STORAGE OF MATERIALS. Deliver materials to job site in original undamaged containers and store materials off the ground protected from moisture and dampness.

2.03 MATERIALS.
Materiáls shall conform to requirements of the referenced specifications and standards and to the requirements specified herein:
a)   Portland Cement – ASTM C-150
b)   Hydrated Lime ASTM C-206
c)   Perlite Aggregate – ASTM C-35
d)   Sand Aggregate ASTM C-144
e)   Water: Clean and Potable
f)   Air-Entraining Admixtures: Liquid neutralized vinsol resin, or equal, as supplied by the perlite aggregate manufacturer: EXOSEL OS POWDER BY ATAMAN CHEMICALS

2.04 PLASTER PHYSICAL PROPERTIES.
The perlite-portland Cement plaster shall have an oven city density of lbs I ft a (kg I rn3) and a minimum compressive strength of lbs I in 2 (kPa) at 28 days.

PART 3. EXECUTION
3.01 PROPORTIONS AND APPLICATION.
Mix perlite portland cemeñt in a paddle type plaster mixer. Mik requiréd amount of water and air entraining agent in the mixer followéd_ by the cement and mix until a slurry is formed. Add proper amount of perlite aggregate to the slurry and mix until required wet density is reached. See Table 1 for proper mix proportions of all perlite portland cement based plasters and apply in three coats to not less than the specified minimum thickness. Note: On small jobs, two coat application, where allowable by code, is acceptable. Apply second coat as soon as the first coat has attained sufficient rigidity. Sand may be mixed with perlite aggregate in the maximum ratio of 1:1 to increase the tensile strength except in fire rated construction.
Expansion Joints. Install through-wall joints a maximum of feet ( metres ) apart to permit contraction and expansion of all continuous wall areas, and at all points where the wall abuts columns or other framing members. Installation shall be such as to prevent structural movement from being transmitted between walls and framing members. Cure perlite portland cement plaster for a period of 48 hours and keep damp during this period.
Note: All numerical values include Sl (International System ot Units) equivalents. Dimensions are nominal for both U.S. and Sl systems of measurement.

PERLITE-GYPSUM PLASTER

PART 1. • GENERAL
1.01 SCOPE.

The plastering contractor shall furnish all labor, materials, equipment and supervision for installing the perlite-gypsum base coat plaster and finish coat in accordance with the recommendations as published by Perlite Institute, Inc., applicable drawings, and contract documents. Application of perlite-gypsum base coat plaster and finish coats shall be in accordance with ANSI Specification A42.1.
1.02 WORK BY OTHERS.
Furring and lathing, sprayed fiber and cementitious mixtures, spray applied decorative finishes, gypsum wallboard or additional material shall be provided by others.
PART 2. PRODUCTS
2.01 IDENTIFICATION AND MARKINGS.
Identify packaged materials with manufacturers’ brand name. Provide similar information in the shipping advices accompanying the shipment of bulk-materials. 2.02 DELIVERY AND STORAGE OF MATERIALS. Deliver materials to job site in original undamaged con. tainers and store materials off the ground protected from moisture and dampness.
2.03 MATERIALS.
Materials shall conform to requirements of the referenced specifications and standards and to the requirements specified herein:
a)   Gypsum Neat    ASTM C-28
b)   Perlite Aggregate – ASTM C-35
c)   Water: Clean and potable

PART 3. EXECUTION
3.01 PROPORTIONS AND APPLICATION.
General: All metal lath surfaces and gypsum lath ceil. ings attached by resilient clips shall be three-coat work. Unit masonry and gypsum lath may be either three-coat or two-coat work. Three Coat Work.
1) Scratch Coat: First coat shall be not more than 2 cubic feet (57 litres) of perlite to 100 lbs. (45.3 kg) of neat gypsum. On masonry surfaces, except
TABLE 2. RECOMMENDED MAXIMUM PROPORTIONS OF PERLITE PER 100 lb. (45.35 kg) OF GYPSUM PLASTER
DOUBLE.UP
   SCRATCH COAT   BROWN COAT
PLASTERING
GYPSUM LATH
   (57 lit(es)   (57 litres)   (57 litres)
•MASONRY
   (57 litres)   (57 litres)
METAL LATH
   (85 litres)   {85 Iätres)   (85 litres)
•   Except monolithic concrete.
•   ‘Where piaster is I inch (26 mm) or more in total thickness the proportions for the second coat may be increased to 3 cu. ft. (85 litres).
monolithic concrete, the mix shall be not more than cubic feet (85 litres) of perlite to 100 lbs. (45.3 kg) of neat gypsum.
2) Brown Coat: The second coat shall be not more than 3 cubic feet (85 litres) of perlite to 100 lbs. (45.3 kg) of neat gypsum.

Two Coat Work.
1)   Gypsum Lath The mix for double-up work shall be not more than 2 cubic feet (57 litres) of perlite to 100 lbs. (45.3 kg) of neat gypsum.
2)   Unit Masonry – The mix shall be not more than 3 cubic feet (85 litres) of perlite to 100 lbs. (45.3 kg) of neat gypsum.
3)   Monolithic Concrete – A leveling coat mix of not more than 3 cubic feet (85 litres) of perlite to 100 lbs. (45.3 kg) of neat gypsum shall be applied over an approved liquid bonding agent.
4)   Proportioning of Finishing Coat When a smooth trowelled lime putty gypsum finish is used, it shall contain perlite fines in the proportions of .5 to 1.0 cubic feet (14 to 28 litres) per 100 lbs. (45.3 kg) of gauging plaster.
Specifications presented herein incorporate portions of American National Standards Institute, Standard Specification for Gypsum Plaster. ing A42.1 but vary in format and content to conform to the current recommendations

Perlite for Textured Coatings
The physical character of expanded perlite lends itself to a variety of special purposes—including use in textured coatings

Advantages ofPerlite
Perlite offers advantages to both manufacturers and applicators of textured coatings.
To manufacturers, perlite provides low cost bulk filling and a white color to reduce pigmentation costs.
Because perlite is light in weight, shipping and handling costs are reduced.
The light weight of perlite textured coatings reduces the tendency of thick films to sag and run.
As a result, applicators can apply heavier coatings in a single pass with subsequent labor savings.
In addition, because perlite is inorganic and inert, it does not contribute to yellowing in industrial atmospheres.
Even as a coating, applicators can benefit from perlite’s unique insulating properties.
Variety of Textures Possible
Perlite is available in different grades ranging from fine to coarse material.
The table below provides general guidance on textures that may be achieved with different perlite particle sizes.
Textured Coating Formulation
On a volume basis, significant quantities of perlite may be used to produce distinctive textures.
Trials should be conducted to determine

the optimum amount of perlite necessary to achieve the desired texture.
Application ofPerlite Textured Coatings
Textured coatings may be formulated for either spray or roller application. Heavy duty spray equipment may be used to apply perlite textured coatings.
Typical tip sizes are detailed in the table, left.
When coatings are to be applied with rollers, 3/4 to 1-1/4 in. (18-30 mm) long nap rollers or a honeycomb foam roller should be used for fine and medium textures.
For coarse textures, a deeply patterned roller is recommended for best results.

Aggregate Blending
Expanded perlite is a mineral aggregate and the coarser particle sizes will not withstand high shear rates during mixing.
Slow speed mixing with broad paddles is recommended.
Mixer horsepower requirements would be approximately 10 horsepower per 250 gallon (1000 liter) batch at mixing speeds in the range of 50-200 rpm.
Formulations requiring a high level of shear should be mixed with high speed equipment prior to the addition of perlite.
Provisions should be made to allow for 40% bulking while perlite is being added to the coating mix

Perlite for Underslab Insulation

Easy-to-install, light-weight bags are Using Perlite in Bags
laid unopened below concrete floors

Concrete slabfloors with direct thermal contact to the ground can present challenges to the maintenance of personal comfort in homes and add to heating bills.
A solution to break that direct thermal contact is to use a natural insulative material such as perlite.
Perlite conforming to ASTM C549, and provided in easy-to-install, light-weight bags (either plastic or paper) may be used as insulation below concrete floors as demonstrated in the accompanying photographs and schematic diagrams.
Perlite underslab insulation is a natural, inorganic product that does not rot, support combustion nor provide a habitat for rodents.
Because of its neutral pH, the product does not foster corrosion in piping and electrical wiring that may be in the underfloor area.
Benefits from installation of such a system can accrue in both summer and winter. During winter, heat loss through the floor of a building can be decreased, while in summer, differences (continues) between floor and air temperatures are minimized and condensation on cool floors is avoided— providing a more comfortable and energy-efficient environment.
This system is particularly useful when radiant under-floor heating is employed since the thermal resistance of the perlite will reduce heat loss from the heated slab to the ground below.
In addition, perlite is dimensionally stable under varying temperatures and it is not combustible.

“SUPER” INSULATING PERLITE FOR EVACUATED CRYOGENIC SERVICE

Expanded perlite is used for a wide variety of insulating applications ranging from cryogenic vessels requiring ‘super’ insulation to low temperature and high temperature applications, lightweight perlite insulating concrete, insulating board, insulating plasters, masonry wall insulation and underfloor insulation.

Perlite “Super” Insulation
For cryogenic applications of -150°F (-101°C) and below requiring “super” insulation, evacuated perlite provides a superior insulation with thermal conductivity up to 40 times less than 0.200 Btu-in/h-ft3 °F (0.029 W/m-K) depending on vacuum and temperature.
Usual applications for evacuated perlite insulation are in double walled helium and hydrogen storage spheres.
It may also be used for storage of oxygen, nitrogen and LNG when especially low thermal conductivities are desired.
In addition to large field erected storage tanks, evacuated perlite is used to insulate smaller shop fabricated vessels designed for the storage of many of the cryogenic gases.

Properties of Perlite Insulation
Perlite insulation suitable for evacuated cryogenic service exhibits low thermal conductivity throughout a range of temperatures, pressures and densities.
The normal recommended density range is 8 to 9 ½ lb/ft3 (128 to 152 kg/m3).
The accompanying graph provides data on thermal conductivity for expanded perlite with a density of 8.7 lb/ft3 (139 kg/m3) at mean temperatures from 0°F (-18°C) to -160°F (-107°C).
Cryogenic temperatures are generally considered to be below -150°F (-101°C).
Thermal conductivity of evacuated perlite is many times lower than that of nonevacuated perlite insulation.
For example, at a mean temperature of -115°F (-82°C), normal unevacuated cryogenic perlite at 4 lb/ft3 (64 kg/m3) would have a thermal conductivity about 22 times as great as evacuated perlite at 8.7 lb/ft3 (139 kg/m3) and interstitial pressure of 10 microns.

In addition to excellent thermal properties, perlite insulation is relatively low in cost, easy to handle and install, noncombustible and meets fire regulations, reduces insurance rates and does not shrink, swell, warp or slump.

Perlite for evacuated service must be dry.
The normal moisture limit is 0.1 percent by weight.
Moisture in the perlite greatly increases the pump down time necessary to achieve the low vacuum required.
As a result, perlite must be fresh and packaged in moisture-proof bags or sealed tank trucks.
Perlite bagged in paper sacks should not be used.

Typical Evacuated Perlite Installation
Field installation of perlite super insulation for large evacuated cryogenic vessels requires that a vacuum be maintained in the annular space of the vessel being insulated.
Expanded perlite is pressurized with nitrogen in a tank truck and drawn into the annular space by a combination of vacuum and pressure.
For small vessels, where vacuum transfer is not practical, direct conveying of dry perlite by means other than vacuum, under strictly controlled conditions, produces satisfactory results.

Portable perlite expansion plants complete with dust control equipment and an intermediate two- compartment tank truck are used to expand the perlite on-site and to fill the annular space with evacuated cryogenic grade perlite insulation in a dust-free, moisture-free manner.

Perlite as High Temperature Insulation
Rapid heating expands perlite to produce extremely efficient high-temperature insulation.

Perlite ore, when expanded, takes on a lowdensity cellular structure that makes it an extremely efficient high-temperature insulation material. For a detailed explanation ofperlite expansion, see PDF info sheet: Why Perlite Works.
Perlite gradation (particle size) has only a minor effect on the insulative value. The apparent thermal conductivity, ka, of expanded perlite is shown in the following figure for temperatures up to 18000F (98000.
Perlite can safely be used over a wide range of temperatures as indicated by the physical properties in the following table.

This traditional wood-fired pizza/bread oven uses perlite as an insulator to hold and stabilize the heat.

Residential and Recreational Uses
Lightweight, non-combustible, insulating perlite concrete—as well as loose expanded perlite—has been found to be useful in the construction of other products involving fire: fireplace chimneys, specialty stoves (such as fuel efficient rocket stoves used for cooking) and wood fired bread and pizza ovens.

TEMPERATURE LIMITS FOR PERLITE
Softening Point
Fusion Point 1600-20000F 871-10930C
2300-24500F 1260-13430C
Expanded perlite is widely used alone or mixed with cement for perlite concrete and used for a variety of applications, including chimney liners.

Perlite as High Temperature Insulation
Temperatures in these applications are far below those experienced in foundry use.

Perlite is added to foundry core and molding sand mixtures as a cushioning agent to compensate for the expansion of crystalline silica as it goes through phase changes at temperatures in excess of 10000F (54000. Casting defects such as buckles, veining, fissuring and penetration are minimized and cleaning room costs are reduced.
In addition, perlite improves permeability of core sands thus reducing defects attributable to poor venting

Foundry Applications
Expanded perlite is used as an insulating cover on the surface of molten metal to prevent excessive heat loss during delays in pouring; to top off ingots; to produce refractory blocks and bricks; and in important foundry applications such as lightweight castables.
Perlite is often mixed (3-20% by weight) with exothermic powders and used in hot tops and risers to prevent shrinkage cavities in ingots and castings.
Formed shapes are often employed which take the form of hollow cylindrical sleeves for risers and panels for hot tops.
These shapes perform essentially the same function as hot topping and risering powders and compounds.

Perlite for Non-Evacuated Cryogenic and Low Temperature Service
The physical character of expanded perlite lends itself to a variety ofspecial purposes—including use in insulating cryogenic and low temperature storage tanks, in shipping containers, cold boxes, test chambers, and in food processing.

Storage temperatures of -150F (-1000 and below are considered cryogenic. Storage temperatures of -150F (-1000 and above to +40F (+40 are considered low temperature. Super cold or extremely cold cryogenic fluids such as hydrogen and helium are normally stored in spherical, double-walled vessels with perlite-filled annular spaces.

Perlite for Non-Evacuated Cryogenic and Low Temperature Service

NON-EVACUATED PERLITE
CRYOGENIC AND LOW TEMP INSULATION SPECIFICATIONS
Density 2.5 to 5 lbs/ft3
40 – 80 kg/m3
Sieve Analysis (mesh is U.S. Standard)
Percent Weight Retained
Max. 100/0+16 mesh (1.18 mm) Min. 50 0/0+100 mesh (0.15 mm)
Thermal Conductivity*
Low Temperature Applications
(at mean temperature -400F, -4000
0.24-0.27 Btu • in/h • ft2 • OF
(0.035-0.039 W/m.K)
Non-evacuated Cryogenic Applications
(at mean temperature -195 0F, -12600
0.17-0.20 Btu • in/h •ft2 • 0F
(0.025-0.029 W/m.K)
* Thermal conductivity varies with temperature, density, pressure, and conductivity of the gas which fills the annulus or insulation space.
Properties ofPerlite

Insulation
Perlite insulation suitable for non-evacuated cryogenic or low temperature use exhibits low thermal conductivity throughout a range of densities, however, the normal recommended density range is 2.5 to 5

Typical Non-Evacuated Installation
There are many different design concepts for low temperature and cryogenic storage vessels.
Most are of double-walled construction with the annular space filled with expanded perlite.

Perlite as a Filler
The physical character of expanded perlite lends itself to a variety of special purposes—including use as a filler material in milled flake form, aggregate bubble form, and individual microspheres

Perlite Flake
Perlite glass flake consists of broken, expanded perlite particles to form glass flakes with an interlocking, 3-dimensional structure. This structure helps reduce shrinkage upon drying or
curing, maintaining the physical dimensions of the host material.
Typical uses for perlite glass flake fillers are water-based construction compounds, paints, asphalt, concrete, plaster, and resin-based castings.
Flake size is, generally, below 300 microns (50 mesh) in size – averaging between 20 and 70 microns in diameter. Density ranges from 5 to 15 lbs. per cubic foot (80 – 240 kg/m3).

ADVANTAGES OF PERLITE AS A FILLER
■ Weight reduction
■ Shrink and/or crack resistance
■ Low volume-based cost compared to binders and some other fillers
■ Whiteness
■ Impact resistance
■ Machinability and ease of sanding
■ Nail and screw holding ability
■ Flexural strength modification
■ Very fine texture in coatings
■ Gloss and sheen control
■ Pigment extension
■ Inertness and non-toxicity
■ Water and/or air permeability
■ Fire resistance
■ Insulation
■ Modification of acoustic properties ■ Available in various sizes and densities

Perlite Bubbles
Perlite fillers made up of clusters of glass bubbles are used in a wide variety of applications – some of the most common being in the production of acoustic ceiling tiles, lightweight cement, and insulating plasters. Particle sizes range from 1,000 microns (16 or 18 mesh) down to below 200 microns (80 mesh). Densities can range from 4 lbs. per cubic foot up to about 19 lbs. per cubic foot (64 – 300 kg/m3). Other applications include use as a constituent in fire-rated door cores, where light weight, inert and inorganic qualities enhance fire

Perlite Microspheres
Perlite microspheres are a special subset of perlite fillers and require advanced manufacturing and classication techniques to produce.

They consist of discreet hollow spheres of expanded perlite – generally between 10 and 300 microns in size.
Densities vary from 6 lbs. per cubic foot to as high as 28 lbs. per cubic foot (96 – 450 kg/m3).
Perlite microspheres are sometimes coated to enhance hydrophobic qualities or bonding properties needed for certain applications.
Specialized technology now allows the production of individual, unbroken perlite bubbles and further classication can lead to even more uniform qualities for special uses. e spherical nature of these microspheres enhances owability.

Perlite for use in well cementing applications.

Well cementing is the process of introducing a cement mixture, consisting of Portland cement, additives, and water, to the annular space between the well bore and casing, or the space between two successive casing strings.
This viscous slurry is forced out through the bottom of the drill casing and the space between the well bore and the casing. Well cements serve the following purposes:
1) seal uid movement between permeable layers and prevent contamination of the well source,
2) support the casing string and well bore wall, and
3) protect the casing from corrosion.
Functions of Well Cementing Additives
Well cements are of particular interest where extreme temperature and/or pressure is concerned.
For example, casings and well bores may be subjected to temperatures ranging from below freezing in permafrost zones, to as high as 300 °C (575 °F) in thermal recovery and geothermal wells.
Temperature and pressure varies with well depth and type as well, reaching as high as 200 MPa (29,000 psi)*.
Due to the inherent extreme environment involved in well drilling, additives, such as perlite, are used alongside Portland cement to ensure effective performance under these conditions.
Additives exist to enhance the properties of well slurries and promote successful placement between the casing and the geological formation.
They also improve compressive strength and zonal isolation over the lifetime of the well.

Perlite Well Cements
Substituting perlite for other conventionally-used materials oen has the eect of lowering the overall density of the well-cement mixture.
The density of materials such as diatomaceous earth (DE), pozzolan, Fly ash, and glass microspheres and beads typically ranges between 400 – 1,600 kg/m3 (25 – 100 lb/cu ), whereas expanded perlite has a dry-density well below 250 kg/m3 (16 lb/cu ).
Substituting perlite puts less pressure on surrounding geologic layers, and lowers on-site demand on labor and equipment.
Perlite can also be introduced in higher concentrations as needed.
Other materials, such as bentonite clay (or “gel” as it is known) must be incorporated along with a fair amount of water.
Water adds to the density of the mix, plus, it is incompatible with high heat.
With a melting point far exceeding the temperatures normally encountered in a well, and the ability to be incorporated without extra hydration, perlite is a natural choice for high heat situations where a lower density slurry is advantageous.
Finally, materials on-hand are used more effectively and costs are lowered when perlite is specified.

Perlite Lightweight Cement can bridge voids and fill fractures in rock layers more easily than other mixtures, which minimizes loss to adjacent layers and costly remediation measures.
Expanded perlite consists of up to 95% trapped air by volume, making it an excellent functional filler, and offset for more costly materials, or those that are becoming increasingly rare.

Advantages of Perlite Well Cements:
Ease of use and lower on-site mechanical requirements
Increased thermal performance
Compatible with high temperatures
Increased impact strength and rheology
Stops contraction under thermal conditions
Higher yields with lower density
Improved bridging; seals fractures more rapidly due to the lower plastic viscosity
Excellent fluid loss characteristics; retains key characteristics of slurry for longer (e.g. viscosity, thickening time, density and compressive strength)
Reduced pressure on surrounding geologic layers
Available in a wide range of sizes and densities

Perlite is available in a wide variety of grades and sizes allowing for the adjustment of cement slurry properties.
An appropriate selection is important to meet the needs of different API classes.

Perlite as a Sludge Absorbent
When perlite ore is expanded by exposure to controlled heating, it grows up to 20 times its original volume and takes on a foam-like cellular internal structure – essentially clusters of microscopic glass bubbles.
Fine grades of perlite are mostly broken portions of these clusters, exhibiting a very large surface area, lending themselves to the efficient absorption of liquids

Why Absorb Sludges?
Generally, waste landfills will not accept liquid wastes – they must be solidified or stabilized first.
The measure of this solidification in the U.S. is established by the Environmental Protection Agency and is determined by a simple procedure called the “Paint Filter Test”.
Basically, if no liquid drips out of a paint filter over a 5 minute test period, the material is defined as a solid.

Why Use Perlite?
Expanded perlite fines are especially useful in solidifying sludges because they can absorb a high percentage of liquid while adding minimal additional weight.

Absorption of liquids on solids is a simple process based on complex factors such as void volume, surface tension, surface area and liquid viscosity.
Of course, water, with its high surface tension and low viscosity, may show higher absorption than many other liquids.
Testing is recommended to determine how much perlite is needed to stabilize specic types of liquid waste or sludge.

PERLITE AS AN ABSORBENT OR CARRIER

What is Perlite?
Perlite is not a trade name but a generic term for naturally occurring siliceous volcanic rock. The distinguishing feature which sets perlite apart from other volcanic glasses is that when heated to a suitable point in its softening range, it expands four to twenty times its original volume.

This expansion is due to the presence of two to six percent combined water in the crude perlite rock. When quickly heated to above 1600° F (870° C) the crude rock pops in a manner similar to popcorn as the combined water vaporizes and creates lightweight particles with countless internal cells and high surface area. It is this multicellular nature and high surface area which accounts for the excellent absorption properties of perlite.

The expansion process also creates one of perlite’s most distinguishing characteristics: its white color. While the crude rock may range from transparent to light gray to glossy black, the color of expanded perlite ranges from snowy white to grayish white.

Expanded perlite can be manufactured to weigh from 2 lb/ft3 (32 kg/rn3) to 15 lb/ft3 (240 kg/m3) making it adaptable for numerous uses, including filtration, horticultural applications, insulation, inert carriers and a multitude of filler applications.

Perlite as an Absorbent

Expanded perlite can be used to control and clean up liquid spills. The perlite may also be used to provide rapid deoderization and dehydration of animal waste liquids. In these applications the perlite may be use din granular form and compressed into pellets of the desired size and shape. Perlite is also suggested as an absorbent media in enclosed containers for the disposal of liquid toxic waste substances.

By activating the expanded perlite with hydrochloric acid and/or sulfuric acid the material can be used as a purifying agent for waste and process waters.

Perlite as a Carrier

Expanded perlite is recommended as a carrier for pesticides, feed concentrates, herbicides, and other similar applications.

As a carrier for feed concentrates perlite will readily absorb the concentrate while remaining free flowing (anti-caking), and chemically resistant to micro-biological degradation. The perlite also permits quick liquid movement between the carrier surface and the recipient of the feed concentrate.

Perlite for Water Quality Management
The physical character of expanded perlite lends itself to a variety of special purposes—including various applications in the broad category of water quality management. For a detailed explanation of perlite expansion see info-sheet: Why Perlite Works.

Storm Water Filtration
Due to its high surface area, neutral pH and irregular, porous surface texture, expanded perlite is ideally suited for a variety of applications in storm water filtration; most notably as a component in media filter drain mixes, and another as an element of catch basin filter media.
Roadside Media Filter Drains—Developed by Washington State Dept. of Transportation (WSDOT), media filter drains incorporate horticultural grade perlite, dolomite, and agricultural gypsum held in place by crushed rock, and are placed along roadways to filter suspended solids and other pollutants from roadway runoff.
Catch Basin Filters—Various filtration media—including expanded perlite—are used to remove contaminants from storm water runoff passing through catch basins before being released to local sewer systems and waterways.

Perlite for Water Quality Management

Rainwater Surge Reduction & Green Roofs
Horticultural perlite is used as a light weight constituent of soil mixes that make up vegetated roofs.
Among the benefits of these roof-top gardens, is the ability to temporarily hold and slow the surge of rainwater encountered during heavy or prolonged rain events.
Many municipalities offer credits or other incentives to developers when eco-roofs are incorporated into new building designs.

Roof-top gardens designed with lightweight perlite growing media, reduce the rate of discharge to catch basins and sewers, improving turbidity levels overall in local streams and rivers.

Soil Stabilization and Liquid Waste Solidification
Tests have shown that the porous structure of fine grades of expanded perlite allows it to absorb up to 8 times its weight in water.
This ability underlies its use to stabilize highly saturated soils, water from well drilling services, and other hazardous, liquid wastes.

Filtration
Perlite’s role in filtration of liquids is well documented (and described in detail elsewhere on perlite.org). It plays an important role in municipal and industrial water treatment systems where it is used in conjunction with a rotary vacuum drum filter to remove solids and other contaminants from polluted waste water.

PERLITE FILTER AIDS
By definition, a filter aid is an agent consisting of solid particles that improves filtering efficiency by

building up a porous, permeable and rigid lattice structure—the filter cake—that retains solid particles and also helps flow control.
The septum, usually screen or cloth, serves principally as a support for the filter cake.
The filter aid forms a porous layer on the septum and becomes the filtering medium that traps the solids and prevents them from blinding the septum.
Irregularly shaped particles interlace and overlay leaving open spaces—billions of microscopically fine interstices—between the filter aid particles.
The size of these openings is so minute that the unwanted solids are strained from the liquid, and the sheer number of openings compensates for their small size, resulting in fast flow rates and brilliant clarity.
Filter aids may be applied either as precoat on the septum and/or as body feed in the liquid.
As precoat, filter aid can be applied as a thin layer over the filter before the suspension is pumped to the apparatus.
A precoat prevents fine suspension particles from becoming so entangled in the filter medium that its resistance becomes excessive.
Further, it facilitates the removal of cake at the end of the filtration cycle.
■ Local supply—near the use point
■ Specially tailored to the local application
■ Minimal lead time
■ Low filter cake density (< 270 kg/m3)
■ Wide permeability
■ Less cake cracking and easy cake release
■ Wide variety of properties (density, size) ■ More economical filtration (same volume, half mass)
■ Perlite filter aids satisfy the US Food Codex and relevant EU regulations

ADVANTAGES OF PERLITE FILTER AID
Not chemically modified material
■ Sterile and inert nature
■ Safe handling and easy disposal

Usually, the thickness of the precoat is between 1.5 to 3.0 mm, thus 1.5 to 3 L of wet perlite filter aid are needed to coat about 1 m2 of septum surface [1].
In any case, precoat characteristics can only be determined after the implementation

Filter aid material can be incorporated with the suspension before introducing it to the filter. The addition of filter aids increases the porosity of the cake, decreases its compressibility, and reduces its resistance. Typical filter aid additions are in the range of 0.01 – 4% by weight of suspension; however, the optimum amount can and must only be determined from experiments. Excess amounts of filter aid will decrease the filtration rate[1]. Low shear agitation of the slurry is required for perlite filter aids. High shear, high concentrations will result in uncontrolled breakdown of the perlite.
Perlite Filter Aid Grades & Applications
Perlite filter aid is created through the expansion of perlite ore, the milling of that expanded perlite, and the classification of milled expanded perlite using cyclonic air separation.
A range of perlite filter aid grades are produced, some finer, and some coarser, with varying technical properties to optimize filtration capacity for a wide variety of applications. The various grades utilize the jagged interlocking structures of the particles to create billions of microscopic channels between the filter aid particles.
The flow rate of various filter aid grades is calculated using Darcy’s Law, which expresses permeability as the rate of flow of fluids through porous media. A filter medium with a permeability of 1 darcy allows the flow of 1 cm³/s of a fluid with viscosity 1 cP (similar to water) under a pressure gradient of 1 atm/cm acting across an area of 1 cm². The determination of the filter aid grade with optimum filtration performance and effectiveness can only be done after experiments.
Perlite vs. Diatomaceous Earth (DE)
Diatomaceous earth (DE), or simply diatomite, is made from the fossilized remains of tiny, aquatic organisms called diatoms.
Their skeletons are made of a natural substance called silica. Over a long period of time, diatoms accumulate in the sediment of rivers, streams, lakes, and oceans. This material is mined and calcined (heated at high temperature) to destroy any organic matter and agglomerate the diatoms together to achieve different rates of flow. The diatomaceous earth is then milled and separated into various filter aid grades through the use of air flotation[2].
Perlite filter aids are functionally like DE filter aids, and usually both are used when the collected solids are not wanted for subsequent treatment[3]. However, the different origin and physicochemical properties render perlite advantageous in the following ways:

Perlite has 30-50% less bulk density thus comparable filter applications typically require 30%-50% less additive.
Perlite filter aids form lower density cakes than diatomite filter aids of comparable or better permeability and filtration fluxes.
Perlite filter aids generally contain no, or very little crystalline silica, thus do not pose a health hazard.
As a consequence of its inert nature, perlite filter cake is not subject to the strict regulations governing its disposal.

Health & Safety
Perlite is an inert, non-crystalline material of aluminosilicate composition that does not impart taste, odor or color.
It is listed in the US Food Chemicals Codex and in relevant EU regulations, while its use in feedstuff is widespread. Perlite filter

Perlite filter aids are Generally Recognized as Safe (GRAS) for use in food processing. All foods and beverages must be filtered with products made from components complying with international food and drug regulations for food contact use[8]. Furthermore, depending on what is being filtered, spent perlite filter cake may contain nutritious by-products that have been strained out of the original liquid. These can be reclaimed, composted, or used as a stock feed.
Perlite filter aids are not considered dangerous to human beings, and no hazard warnings are generally required for perlite products. Some DE grades

contain crystalline silica, which is a carcinogen, and must be listed as a hazard to inhalation in any associated Safety Data Sheet. On the other hand, perlite is regarded as what was formerly termed a ‘‘nuisance dust’’, thus it is still recommended to use a respirator when dispensing it to minimize inhalation.
Replacement of DE with Perlite
Perlite filter aids can be used with both pressure and vacuum filtration equipment by merely replacing present DE material volumetrically. It is quite common to use the same grade of filter aid for both pre-coat and body feed applications. When two different grades are used, the body feed will typically be the more “coarse” or “open” grade. (This does not refer to the grades in dual pre-coat applications).
Several methodologies exist for choosing the correct grade of perlite. One method entails choosing the grade that best removes targeted solids at the flow rate and cycle length required. The other method involves using a grade whose median particle size is comparable to the solids being filtered, i.e., for fine solids use a “fine” grade of filter aid; for coarse solids use a “coarse” grade of filter aid.
Less Mass. Great Performance.

Normally, the thickness of filter aid layer as precoat ranges between 1.5 to 3.0 mm, thus for 1m2 filtration area 1.5 to 3.0 L of filter aid is required. The bulk density of filter aid grade expanded perlite ranges between 100 and 200 kg/m3, possessing mean value of 150 kg/m3, while diatomaceous earth has a bulk density of about 300 kg/m3. A 3.0 mm filter aid layer of 1 m2 filtering surface requires 900 g of diatomaceous earth, or just 450 g of perlite.
The mean bulk density of filter cake is between 100 and 270 kg/m3 (mean 185 kg/m3) when perlite filter aid is used, and between 230 and 420 kg/m3 (mean 325 kg/m3) when DE is used. The perlite filter cake density is approximately 55% lower compared to that of diatomaceous earth.

EXPANDED PERLITE AS A FILTER

The physical character of expanded perlite is ideal for use as a filter aid separating small solid particles from liquids.

A filter aid is a finely graded material which, when added to the liquid to befiltered, collects on the septum (a screen or cloth).
The filter aid forms a porous layer on the septum and thus the filter aid is the filtering medium that traps the solids being removed andprevents them from blinding the septum.

Light weight expanded perlite bubble structures are milled and classified using strictly defined processes to produce perlite filter aids with specific flow characteristics.
The various grades utilize the
aid particles to produce optimum flow rates and clarification abilities for a wide variety of applications.

The Benefits ofPerlite as a Filter Aid
Perlite filter aids are lightweight, inert, impart no taste or odor to liquids being filtered, and are virtually insoluble in mineral and organic acids at all temperatures.
Solubility in strong alkaline solutions varies depending on temperature and contact time.
Without using a filter aid the solid particles in the liquid will soon accumulate on filtering surfaces and block them.
A perlite filter aid makes a filtering layer (cake) that transfers the actual filtering from the septum to the whole mass of filter aid.
Filtration occurs in the tiny pores formed by the fine particles of filter aid.

Volume-Based Pre-coat Filtration provide users with a lightweight filter aid grades provide the advantage from 20 to 50% over aids.
Perlite filter aid dry density ranges from 100 to 200 kg/m3 (6 to 12 lb/ft3), and the filter cake density range is 100 to 270 kg/m3 (7 to 17 lb/ft3).
In contrast, other filtration materials produce equal performance filter cakes in the range of 230 to 420 kg/m3 (15 to 25 1b/ft3).
Expanded perlite provides larger volumes with low bulk density compared to other filter aids.
Experience in a variety of applications has shown that most filter aid users can economically switch to perlite from other pre-coat filter aids without sacrificing performance.

Inert Nature of Perlite

Approval for the use of perlite as an additive in animal feeds was recently extended in the European Union.
Generally, spent filter aid cakes from wineries, breweries or other food-related industries may be added to animal feed.
Such practices reduce the environmental footprint of those industries as well as reducing disposal costs for the used material.
Approval for this application in the United States comes from the Association of American Feed Control Officials (AAFCO).

Perlite for Filtration

Approval for the use of perlite as an additive in animal feeds was recently extended in the European Union.
Generally, spent filter aid cakes from wineries, breweries or other food-related industries may be added to animal feed.
Such practices reduce the environmental footprint of those industries as well as reducing disposal costs for the used material.
Approval for this application in the United States comes from the Association of American Feed Control Officials (AAFCO).

Usable With Standard Equipment
Perlite filter aids are both sterile and inert and are used for filtering liquids in the beverage, food and pharmaceutical industries.
No tastes, colors or odors are imparted, and, subject to meeting the standards listed in the Food Chemicals Codex (published by the United States’ National Academy of Sciences), are deemed safe for their intended use. Note: The Food Chemicals Codex is regarded as a source of information on the quality and purity of food grade substances, and is regarded as authoritative by many government agencies throughout the world. (continues) Perlite filter aids can be used with either pressure or vacuum filtration equipment. Perlite generally replaces other filter aids on a one-to-one volume basis – for example; a cubic measure of perlite will replace the same volume of other filter aids. Selection of the optimum grade and dosage may require plant or laboratory filtration tests.

Flow Rates ofGrades
Perlite filter aid grades from various manufacturers range from 0.2 – 6 Darcies. (The Darcy is a common unit of flow rate for filter aids.)
A material with a permeability of one Darcy passes 1 milliliter per second per square centimeter of a liquid of 1 centipoise viscosity (approximately that of water) through a cake 1 centimeter thick at a differential pressure of 1 atmosphere.
The higher flow grades are especially applicable to use with highly viscous liquids such as syrup, resins or gelatinous slurries.
Productivity, clarity and flow rates may be increased through the use of perlite filter aid grades.
These traits are accomplished during the liquid’s path through the channels created by the jagged, interlocking particles.

Easy Cake Release
Additional benefits of perlite filter aids come at under pressure release easier when perlite is used.
This release facilitates cleaning, potentially reduces manpower requirements, and increases productivity. The lower weight of perlite filter cakes may also reduce disposal costs.

Use by Industry
Perlite filter aids have gained acceptance in almost every industry concerned with the separation of liquids and solids, and even gasses and solids.
The following list, although not all-inclusive, gives an indication of the many applications where perlite filter aids are being utilized due to their low density, availability, performance, economy and environmental footprint.
•   Food Processing: juices, beers, wines, sweeteners, vegetable oils, wastewater treatment
•   Pharmaceuticals: enzymes, antibiotics, Epsom salt
•    Industrial: water treatment, sizings, oil & solvent recovery, greases
•   Chemicals: inorganic & organic chemicals, resins, polymers, brine, adhesives, fertilizers, waste disposal • Paint and Coatings: waxes, oils, varnish, gums, shellac, wastewater treatment
•   Environmental: stormwater filtration, ecology embankments, media filter drains

PERLITE CHIMNEY LINING SYSTEMS SOLVE CONDENSATE PROBLEMS IN OLD AND NEW CHIMNEYS

Condensate, which can form in chimneys when hot gases impinge on cold chimney linings, can create two serious problems. The first is the formation of combustible tars on chimney linings that may cause chimney fires. The second is the formation of sulphite solutions that can attack chimney mortar which can lead to leakage, staining and possibly even chimney collapse.

Other reasons for relining chimneys are to seal broken or cracked masonry work and to improve draft by reducing flue size.

Why Perlite?
Expanded perlite is an ideal material for insulating chimneys as it is inorganic, does not support combustion and exhibits excellent thermal insulating properties over a wide range of temperatures. In addition, it is not affected by most acids. Perlite chimney insulation may be mixed oil-site but premixed material is commonly used to ensure consistent quality control. For new construction, perlite loose fill chimney insulation may be used between the flue and the body of the chimney.

Perlite is not a trade name but a generic term for naturally occurring siliceous volcanic rock. The distinguishing feature which sets perlite apart from other volcanic glasses is that when heated to a suitable point in its softening range, it expands from four to twenty times its original volume.

Expanded perlite can be manufactured to weigh from 2 lb/ft3 (32 kg/m3) to 15 lb/ft3 (240 kg/m3) making it especially suitable for use in insulating applications. Perlite is used in the manufacture of lightweight fire resistant concrete for chimney linings, cryogenic, low temperature and high temperature insulations, lightweight perlite concrete, insulating board, insulating plasters, loose fill insulation for masonry walls and chimneys and as underfloor insulation.

Reconditioning Chimneys
Pumped chimney lining is often used in repair or relining of existing chimneys. In this type of installation, a rubber tube is inserted the length of the chimney to be relined. The tube is supported and sealed off in the firebox or at the base of the chimney and the tube is inflated to the desired diameter. Both round and elliptical tubes are available depending on the configuration of the chimney. Spacers maintain the tube in position in the chimney. Perlite chimney lining is pumped into the space between the tube and the inside of the chimney. When the mix has set for a minimum of 12 hours, the tube is deflated and withdrawn and the top of the chimney is capped off with mortar. As there are many variables involved in a proper installation, trained personnel should be used to prepare mixes and to reline chimneys. In all cases, the procedures and mix formulations employed should meet applicable building requirements.

New Construction
Lightweight perlite loose fill insulation or a lean mix of expanded perlite and cement may be used to insulate new masonry chimneys as they are being constructed. In this type installation, the perlite is poured or pumped between the flue and the body of the chimney as it is being constructed. This same type of construction may be employed when metal flues are being used. In addition to providing excellent insulation, the metal liner is made more rigid.

Expanded perlite can also be used with other binders in the manufacture of prefabricated chimney liners.

INDOOR GARDENING WITH PERLITE

The green revolution has led to the introduction of hundreds of unheard-of plants and has resulted in new life for old favorites. One reason why people grow plants indoors is their ease of culture. In days past, plant lovers would go into the garden and scoop up some soil which they would mix with rotted manure or other compost and use it to pot their plants. Fortunately they can now rely on modern growing mixes containing perlite, sphagnum peatmoss and other components. These mixes are readily available at garden centers, some hardware and department stores.
Perlite is a volcanic material that, when heated to 1600 deg.F (850 deg.C) makes an excellent ingredient for house plant growing mixes. Perlite particles create tiny air tunnels, which allow moisture and oxygen to flow freely to roots. This is important since 98% of all oxygen a plant gets is absorbed through its roots. Poorly drained growing mixes shut out oxygen; root “pumps” shut down and the plant dies from suffocation.
Over-watering is the cause of perhaps one half the cases of plant failure.
Perlite in a growing mix serves as a “life guard”, not only promoting good drainage but allowing precious oxygen to flow to roots.
Perlite makes moisture, oxygen and nutrients readily available to plants.
Because of the unique shape of each particle, plus its permanency, moisture and nutrients can cling to the crevices until the plant needs them, while the granular quality provides quick drainage of excess moisture and allows space for oxygen – vital for healthy plant growth.
Commercial growers as well as home gardeners can buy perlite mixes or make their own. Equal parts of perlite and sphagnum peatmoss and sand (or rotted compost or loam) makes a fine growing mix

while equal parts of sphagnum peatmoss and perlite make an excellent seed starter.

“COMMERCIAL GROWERS AND HOME GARDENERS HAVE FOUND THAT PERLITE IS THE IDEAL ROOTING MEDIUM…”

Perlite for Increasing Humidity Around Plants
Since the average home is extremely dry when the heating system is operating, plant foliage often takes on a scorched look on tips and edges.
One way to overcome this is to set trays of water in the plant area and add perlite.
Set the plants on the perlite which should be kept moist. Water is slowly released into the atmosphere, benefiting the plants.

Perlite Reflects Light
Cloudy winter days often result in poor houseplant or seedling growth.
Light coming in a window can be greatly increased by placing perlite in the bottom of plant trays and on the surface of the growing mix where light rays will be reflected back up to plants. This can make the difference between spindly plants and good stocky growth. The same applies if plants are being grown under fluorescent lights. Just be sure perlite is kept moist so you can take advantage of the extra humidity.

Watering Plants
Frequency of watering depends on the type of plant and size. Most plants prefer the growing media to be “just moist” at all times.
Some plants, like Jade plant and large-leaved Ficus like the growing media to become almost dry before water is applied.
Care should be taken however, to see that the growing media does not become so dry as to cause dropping of leaves or shrinking of the soil ball to the point at which a space forms between it and the pot. When this happens, water rushes down the inside of the pot rather than wetting the root zone. If this happens, or if leaves drop because of lack of water, set the pot in a large pan of tepid water until the whole root ball is moistened. The plant will respond, usually within half an hour. Plastic pots hold moisture longer than unglazed pots, which have pores for air to pass through. Since the soilless mixes contain much lightweight material, you can usually tell by lifting the pot whether or not the mix has dried out completely. With large pots, you can push a wooden dowel probe (like a pencil) into the pot. If it comes out moist you know there is still some moisture left.

Perlite for Starting Seeds
Fine perlite can be used alone as a seed-starting medium or it can be mixed half and half with shredded sphagnum moss or shredded peatmoss. Many seeds have limited “pushing-up” power.
Perlite alone or perlite mixes are ideal for seed starting because they are light in weight.
Moisten the medium thoroughly, then sow the seeds on top. Very fine seeds can be atomized and left to settle into crevices.
Be sure the medium does not dry out. This can be prevented by keeping the seed box subirrigated at all times, until seeds sprout.
A plastic cover over the box helps maintain humidity. Other seeds can be covered with a light dusting of perlite and sphagnum peatmoss.
Another requirement for good seed germination is a constant temperature (for most seeds) of 72 deg. F (22 deg.C).
Water for sub-irrigation can be put directly in the planting tray or a plastic liner can be shaped to hold water.
lace the seed boxes in this liner and keep water in it.

“PERLITE ALONE OR PERLITE MIXES ARE IDEAL FOR SEED STARTING…”

Another use for perlite in seed starting is to give better distribution of fine seeds. Take a clean salt shaker and place about 1/4 inch (6mm) of very fine perlite (perlite may be poured into a sieve and the fine particles shaken out) in the salt shaker. Pour the packet of seeds on top, replace the cap and shake to mix in the seeds with the perlite. Sprinkle the mixture evenly over the perlite/peatmoss seedbed.
Perlite for Rooting Cuttings
Both commercial growers and home gardeners have found that perlite is the ideal rooting medium for cuttings from ordinary houseplants or from woody shrubs, evergreens or vines. It is important to keep the perlite moist at all times and to keep cuttings out of direct sun. If temperatures are cool, rooting is hastened by applying bottom heat. Misting on warm days helps the cuttings retain moisture and hastens rooting. Home gardeners can use a terrarium as a rooting chamber, whereas commercial growers would use a greenhouse, coldframe or hotbed.

A Guide for the Bulk Handling of Expanded Perlite

Scope
The purpose of this guide is to inform producers and users of expanded perlite about the methods available for loading, transporting, unloading and storing expanded perlite in bulk.

In the past, bags have been the principal method of storing and shipping perlite, because the principal use was in plaster, where the material is used in relatively small quantities on any one job. New uses requiring large quantities have been growing more important each year, and therefore it has become necessary to develop more economical methods for storing and transporting the expanded perlite. Bulk handling of expanded perlite and expansion of perlite at the job site are two methods of delivering expanded perlite to the customer without the use of bags.

2. Advantages
a) Advantages as compared with bags
Bulk handling saves the cost of bags. It eliminates the labor of filling the bags at the plant and emptying them at the point of use. It eliminates the problem of disposing of the empty bags. Burning bags is not possible in many areas because of prohibitions against air pollution and fires. The use of disposal services can be costly. Just the labor to gather, tie and load is costly, not to mention the cost of handling and dump fees.
Bulk perlite is often more compact than perlite in bags. Therefore less space may be required in storage areas and transport vehicles.
Bulk storage and transportation systems are usually moisture-proof. Therefore perlite delivery to bulk facilities in a warm dry condition will ordinarily remain free of moisture until it can be used. Bulk storage and handling systems are generally more weather-proof than bags.
A Guide for the Bulk Handling of
Expanded Perlite

The use of bulk shipments often reduces the time required to service a job by 50% or more.
b) Advantages as compared with portable furnaces
The job may be done on a piece-meal basis to a customer’s convenience. During any interruption in job progress, the plant production can be shifted back to bagged perlite for other customers.

There are no set-up charges required and therefore small jobs which are uneconomical for portable plants can be handled much more efficiently with bulk shipments.

It is much more convenient to expand perlite in one’s own plant than out in the field. There is no wasted ore. Any surplus ore left over from a job remains in the plant, and may be used for other purposes. There are no expense accounts for operating personnel working out of town if the perlite supplier is not acting as an installation contractor.

3. Disadvantages
a) Disadvantages as compared with bags
Bulk handling requires extra equipment, which may be costly, complicated or troublesome. Bulk handling usually requires an investment in storage bins in the plant and possibly at the point of use. Close control of quality is difficult because the furnace is often allowed to operate for long periods of time without the type of representative sampling, which is automatically provided when the expanded perlite is bagged.

Job scheduling is more difficult because the cost of the in-plant bulk storage silos makes it difficult to store up enough perlite at the plant so that installation can be done at a faster rate than the production rate of the furnace equipment. One problem to watch for is settlement in the transportation vehicles. The trucks have to be very carefully loaded and shaken as they are being loaded, in order to settle the perlite as much as possible. Otherwise a full payload is not delivered to the job and the freight costs go up.

Perlite stored and transported in bulk is subject to segregation of the various particle sizes. This can be reduced but most likely never completely eliminated. Another problem is the availability of commercial transport trucks. Most of these trucks are used for other purposes and sometimes it is hard to find them. It would not generally be advisable to buy bulk trailers when first beginning with bulk handling, however.

b) Disadvantages as compared with portable furnaces
Transportation and storage expenses are higher because expanded perlite is voluminous. There is a double expenditure for handling and storage of the materials, first for the raw material and then for the expanded perlite. For these reasons, bulk handling is usually a more expensive method of servicing a job than using a portable furnace.

4. Equipment
a) Handling systems for loading and unloading
Handling systems can be pneumatic, mechanical or manual. The pneumatic conveyors can be divided into three classes:
(1)   Low-pressure, high-air-volume systems where the perlite-to-air ratio is very low (1-6 ozs., ratio of 1/50 through 1/500)
(2)   Intermediate systems
(3)   High-pressure, low-air-volume systems with high ratio of perlite to air (1-15 psi, ratio of 1 /3 through 1/10).

A vacuum can be drawn on a storage silo or cryogenic vessel and the perlite is pulled through a hose or pipe, to be settled out in the tank without the use of a cyclone.
As shown here, this is a low-pressure system. It is the simplest method, but unfortunately there is danger of collapsing the outer shell of even a stoutly built tank.
Technically, this problem can be overcome by using a very low-vacuum fan, and providing a vacuum breaker or rupture disc on the line.
However, tank manufacturers are reluctant to allow even a two-ounce vacuum on a vessel, so this method is seldom used.

The same method can be used to draw perlite from a non-pressurized trailer or a portable furnace with the same advantages and limitations.
Cryogenic vessels where the insulating space is to be evacuated are often filled with perlite using a vacuum of more than 14 psi, which makes this a highpressure-differential system.
A filter must be used to keep perlite out of the more sensitive air pump used in this application.

To avoid the question of the danger of collapsing the tank, a cyclone can be erected on top of the tank, with a draft fan to create suction and an air lock to discharge the material into the tank. This is a low-pressure-differential system. A cyclone can also be used on low-positive-pressure systems to obtain better collection efficiency than might be obtained by settling alone.

One low-positive-pressure system employs a venturi to draw the perlite into the stream of air coming out of a blower.
Often a cyclone is used on top of the tank. No air lock is required because the cyclone is under pressure.
A typical intermediate pressure system uses a rotary air lock to feed perlite into an air stream from a positive displacement blower.
Smaller diameter hose or pipe can be used, and no cyclone is needed at the end of the hose to separate the perlite from the air.
Great care must be taken to keep the equipment in good condition and to adjust the air volume and limit the pressure, or the air lock will not feed the perlite. Poor adjustment may also cause blockages in the hose.

One high-pressure system employs three tanks and two valves. Both valves are never open simultaneously. Air pressure is put on the bottom tank.
Perlite is put into the top tank and it progresses by gravity into the bottom tank, from which the air blows it through the hose into the vessel.
The perlite can be carried in so little air that it flows out of the end of the hose like a stream of water.


A variation of this method uses two pressure tanks side-by-side.
While one tank is being filled through an open port, the other tank has its port closed and air pressure is being applied to convey the perlite.
Shut-off valves are provided at the bottom of each tank to keep the line air pressure from blowing up through the tank being filled. The last two methods often employ aeration pads to fluidize the perlite. Valves should have rubber seats for tight shut-off and abrasion resistance, but if the perlite is hot, this is not possible.

Where the perlite must be picked up from a point near the ground or from several points, or if it must be drawn out of a trailer under suction, a “pull-push” system can be used.
This illustration shows a low-pressure device where the air and perlite are drawn by the suction created by a centrifugal fan, which also blows the material into the vessel.
The material, however, is prevented from passing through the fan by a cyclone and air lock which separate out the perlite on the vacuum side and drop it back into the air stream on the pressure side.
A high-pressure, small-hose variation of the previous system has a cyclone and a positive displacement blower.
This type of blower will wear out quickly if much perlite dust passes through it, so a bag filter must be supplied, along with a final filter in case a filter bag breaks.

The high-pressure, low-gas-volume methods have the advantage of permitting the use of reasonable quantities of dried air, dry nitrogen, or any other gas which may be
specified. They also allow more precise deposition of the perlite.

The most conventional automatic conveying method is mechanical as contrasted with pneumatic handling.
A typical application is a screw conveyor being used to convey expanded perlite from the furnace collection system into a bulk tank trailer.
Other applicable mechanical devices are belt conveyors and bucket elevators.
Belt conveyors might seem to be best because of less abrasion on the equipment and less breakdown of the perlite.
However, the perlite tends to blow off the belt, and if the unit is enclosed to avoid this, perlite settles in the enclosure and gets into the idler bearings.
Bucket elevators are not very often used with expanded perlite because light material floats around in the housing and may leak out of small openings in the enclosure.
Screw conveyors have had the reputation of breaking down expanded, perlite, but quite a few companies are successfully using them.
With proper design, breakdown and abrasion can be kept within reasonable limits.

Manual methods can be employed in conjunction with bulk handling in the following ways:

Perlite stored in a silo at the plant can be subsequently put into bags for shipment.
The principal disadvantage of this system is that particle size segregation which occurs in bins becomes all the more apparent when the material is put into bags.

Perlite stored in bags at the plant can be used to fill bulk vehicles.
This is a costly and time consuming procedure and should probably not be used except in an emergency.

b) Trailers
One of the tidier ways of transporting expanded perlite is by the use of a pressurized tank trailer, shown here in the process of filling a vessel.
These trailers were originally available only in the small sizes used for transporting heavy powders like cement.
Singles now have capacities up to 1900 cubic feet and doubles hold 2500-3000 cubic feet, which makes them economical for carrying perlite.

To discharge a load of perlite, a hose is connected to one hopper bottom and pressure is built up until the material begins to flow.
Aeration pads are usually used to fluidize the perlite. Most trailers have blowers capable of reaching 15 psi, but this pressure is not usually needed with perlite.
Air is often used at the entrance to the hose in order to avoid blocking the hose. Too much air can cause excessive breakdown of the perlite.
As soon as the perlite begins to flow, the pressure will usually drop well below the pressure required to start the flow.

The cost of transporting bulk perlite by common carrier tank trailer is over twice the cost of transporting bagged perlite in trailers owned by the expander company.
This freight cost, even for distances under 100 miles, can be as much as half the total delivered cost.
If the pressure tankers are owned by the expander company, this method is substantially less expensive than the use of bags.
During the filling of the tank, it is possible for the driver to hook up to a hose hanging from the side of the tank and blow the perlite into it without any other labor being present.

The limitation on the volumetric carrying capacity of the pressurized tank trailer is the fact that an essentially round cross-section is needed to withstand pressure.
A cylindrical trailer body staying within the legal outside dimensional limits has about 70% of the volumetric capacity of a rectangular van of the same outside dimensions.
This, combined with the fact that most perlite producers have their own bagged goods trailers, has led many producers to consider converting non-pressurizable trailers to bulk service.

A trailer can be equipped with a single screw conveyor located on the center of the trailer bed.
The main difficulty with a single conveyor is that it tends to leave 1/4 of the product in the trailer because of the angle of repose of the perlite on both sides of the screw.
This illustration shows a proposed method of reducing the dead space by raising up two sheets of canvas after most of the perlite has been discharged.
This might be done, for example, by means of small winches located in the upper corners of the trailer, operated by hand cranks at the rear.
The perlite is discharged out the rear of the trailer into subsequent conveying equipment.

It has been suggested that the problem of unloading a conventional non-pressurized trailer can be solved by the use of a tractor equipped with what is known on the west coast as a “flying fifth wheel”.
This equipment raises the front end of the trailer off the ground to provide sufficient slope for the perlite to slide to the rear of the trailer as it is being discharged.
After the perlite has been discharged from the trailer, any of the mechanical or pneumatic methods
previously described can be used to deliver it to the point of use.
A typical combination is shown where perlite emptying from a trailer elevated by a “flying fifth wheel” is being carried away by a pneumatic system involving an air lock and a pressure blower.
Another method of bulk handling without the use of special pressurized trailers is to use tote bins or containers loaded on a flat bed trailer.
These containers can be made of metal, wood, or rubber, and should be fitted with doors for easy filling and emptying.


5. Storage
In order to employ bulk handling, it is practically always necessary to have bulk storage silos at the manufacturing plant or at the point of use, or both.
It would, of course, be possible to load a bulk transport vehicle at the same rate as the furnace produces the expanded perlite.
However, this would normally take several hours, and demurrage charges would be incurred.
Practically the only case in which storage facilities would not be required at the point of use is when the use itself involved a large capacity vessel.
Filling cryogenic vessels is the best example.

In order to prevent particle size segregation in an expanded perlite storage silo, the height should be great in comparison to the diameter.
In this way the silo behaves more like a tube, and therefore little segregation occurs.
Wherever the diameter is of approximately the same magnitude as the height, particle size separation will occur.
This can be minimized by using perforated pipes located half way out from the center to the periphery of the silo.
These perforated pipes tend to draw the perlite essentially uniformly from the upper layer and uniformly across the cross-section of the silo.
A silo equipped with perforated pipe antisegregation facilities is shown.


Another type of separation which can occur is based on density.
If the aggregate contains some particles which are substantially lighter than the other particles, there will be a tendency for these light particles to float on top.
In this case, the first material to come out of the bin would be the heavier material, but at the end of the discharging of the bin, the expanded perlite would be nothing but “fluff”.
The best way of eliminating this, of course, is to try to produce as uniform a particle density as possible.
Another method is to avoid any air being sucked upward through the material, such as through a leaky seal at the bottom.
This air flow tends to make the lighter particles come to the top. If possible, the bin should be completely empty before it is filled again.
Otherwise the bin will eventually fill up with a much higher percentage of “fluff” than was actually in the expanded product.

The filling and emptying of perlite storage silos can be performed with the same type of equipment, mechanical or pneumatic, which is used to fill and empty the trailers.

ow Do Manufacturers Make Perlite?
The little white balls that you see suspended in your soil mix are essentially “volcanic popcorn.” That’s about the best description we came across for this material. Perlite is mainly water, and when manufacturers heat the material at high temperatures, it “pops” just like popcorn in the microwave.

The manufacturers crush the perlite and then bake it in large ovens at 1,650 degrees Fahrenheit. The heat softens the mineral structure, turning the trapped water inside the perlite into steam and expanding it. As the steam escapes, it causes the expansion of the material, and you have the perlite we use in horticultural applications.

During the heating process, the perlite can expand up to 16-times more than its original size. The tiny white, Styrofoam-looking balls are porous, sterile, and stable after cooling.

What are the Benefits of Gardening with Perlite?
There are plenty of reasons why you should add perlite to your soil mix. The unique chemical and physical properties of the material make it suitable for gardening.

Perlite is stable and retains its shape in your soil mix
Perlite has a neutral pH, which makes it ideal as a soil amendment
Perlite contains no chemicals or nutrients
Perlite is a highly porous material
Perlite assists gardeners with water retention in the soil while improving drainage
Aerating the Soil and Drainage
Adding perlite to your soil mix provides you with two primary advantages – drainage and aeration. With more air around the roots of your plants, they grow faster and yield more during harvest. Water is another critical component of plant growth, but overwatering your plants will cause the onset of root rot, killing the plant.

Adding perlite to the soil helps to improve the drainage of water away from the roots while leaving the soil with the right amount of moisture to spur growth.

How Do I Use Perlite in My Garden?
There are several uses for perlite around the garden. Follow these tips to make the most out of this material in your flowerbeds and pots.

Fortify your soil mix – Add a combination of loam, peat moss, and perlite to enhance the drainage and aeration of your soil, while providing a stable growing medium that absorbs nutrition for your plants.
Use it as a surface treatment – Scatter loose perlite over your flowerbed to act as a wicking agent. The perlite will eventually work itself into the soil, improving water retention and draining.
Rooting your cuttings – Perlite helps to encourage root growth in new cuttings. Place your cuttings in a Ziploc, along with moistened perlite. The moisture in the perlite keeps the cutting alive while it starts to form new roots.
Mix the perlite in with your soil
Mix the perlite in with your soil
Are there Different Grades of Perlite?
The perlite used in horticultural applications comes in three different grades, depending on the size of the individual grains.

Fine Perlite – This perlite is the lightest grade available. It’s suitable for rooting cuttings and starting seeds. You can also scatter this type over your flowerbeds and your lawn to improve water retention and drainage.
Medium Grade Perlite – This perlite is the mid-ground between the fine and coarse types. It’s a good choice for potting seedlings.
Coarse Perlite – This grade offers your soil superior drainage, and it has the highest porosity of the three types. As a result of the porous nature of the material, it’s a good choice for water retention and aeration in large flowerbeds and pot plants.
Choose the right grade of perlite to match your gardening application. Perlite is affordable and comes in large 40-lb bags. We recommend you order yours in bulk, especially if you do a lot of gardening.

Is Perlite Organic?
Sure, perlite is a carbon-based material; therefore, it is “inorganic.” However, most farmers and gardeners have a different concept of the word as it pertains to their gardening techniques and their crops.

Perlite is not a “synthetic” material, meaning that its natural, and suitable for use in your garden. It’s not a chemical fertilizer, and it contains no harmful compounds. The National Organic Standards Board certifies perlite for use in organic agriculture.

Therefore, if you plan to build an organic farm, perlite is a safe material to add to your soil, allowing you to retain your organic status.

Which Is Better – Vermiculite or Perlite?
Vermiculite is like perlite. It takes the appearance of a golden/black colored material, looking like small chips of bark. However, vermiculite retains much more water than perlite, and it doesn’t offer the same kind of aerating properties as perlite.

If you saturate vermiculite, it may start to rot if you leave it for too long without drying it out. The material becomes mushy and falls apart. Vermiculite is better for increasing water retention in your soil, while perlite is the better choice for improving aeration.

Production, Origin and General Information – Perlite is a glassy volcanic rock with a rhyolitic composition and 2–5 per cent of combined water (Alkan and Doğan, 1998; Doğan and Alkan, 2004). The main known world’s perlite reserves (about 70 per cent) are located along the Aegean coast in Turkey. The commercial product is produced by heating the ground, sieved material to 760–1100°C. The combined water in the perlite is converted to gas at high temperature in the oven and subsequently the volume expands 4–20 times its original volume, resulting in a lightweight high porosity material. Perlite is frequently used in potting soil mixtures and as a standalone growing medium (Grillas et al., 2001; Gül et al., 2005). It is produced in various grades, the most common being 0–2 and 1.5–3.0 mm in diameter. The various grades differ in their physical characteristics.

Physical Characteristics – Expanded perlite is very light with a particle and BD of 0.9 and 0.1 g cm−3, respectively. It is very porous, has a strong capillary action and can hold 3–4 times its weight in water. Burés et al. (1997a) reported that water retained at 10 kPa is much higher for the coarse fraction (0.5–1.0 mm diameter) than for the fine fraction (0.25–0.50 mm diameter) of expanded perlite. This difference in water-holding capacity between the coarse and fine fractions indicates that most of the water is held by the coarse particles in internal pores. However, it is not explained by the volume of internal porosity alone (Burés et al., 1997a). The slope of the reduction in water content as the water tension increases is moderate relative to sand and stone wool (Burés et al., 1997a,b). The available and non-available water in commercial perlite of 0–4 mm diameter was 13.6 and 36.5 per cent of its volume, respectively (Burés et al., 19975). The water retention curve of perlite shows moderate hysteresis (Burés et al., 1997b; Wever et al., 1997). Wever et al. (1997) reported that the saturation of perlite was very rapid, independent of its initial moisture. The saturated hydraulic conductivity depends on particle diameter (Burés et al., 1997a). For commercial perlite of 0–4 mm diameter, having 50 per cent of the particles smaller than 0.5 mm, saturated hydraulic conductivity was 0.3 cm min−1 (Burés et al., 1997b). A reduction of 2 orders of magnitude in the hydraulic conductivity was obtained as the water suction increased from 0 to 30 cm water (Burés et al., 1997a). This change is moderate in comparison to sand.

Chemical Characteristics – Perlite is neutral with a pH of 7.0–7.5, but it has no buffering capacity and contains no mineral nutrient. When the pH is low there is a risk of toxic Al release into the solution. The chemical composition of the material, as analysed by Olympios (1992), is given in Table 12.4.

TABLE 12.4. Chemical Composition of Perlite, Expressed as Oxides (%)

Oxide SiO2 Al2O3 CaO MgO Fe2O3 Na2O K2O
per cent 73.1 15.3 0.8 0.05 1.05 3.65 4.5
Sterilization, Re-use, and Waste Disposal – Perlite is a sterile product as it is produced at a very high temperature. Chemically, perlite is a stable material, which can last for several years; its stability is not greatly affected by acids or microorganisms. Being an inert material, recycling perlite poses no environmental problems. Re-using perlite without processing to grow successive crops is potentially risky because of media compaction, salt build-up, and pest contamination (Hanna and Smith, 2002). Replacing used perlite with new media to raise successive crops is costly, and recovering the expense by selling the product at a higher price may not work well in a competitive market. Steam sterilization of used perlite before planting a new crop has been recommended to safeguard against pathogen contamination (Wilson, 1988). However, this treatment requires expensive steam generators and may not be adequate to restore perlite’s loose structure and to reduce media salt (Hanna, 2005). In a study conducted to determine if raising tomatoes (Lycopersicon esculentum Mill.) in cleaned and disinfected used perlite would be more economical than new perlite and without any negative effect on yield, Hanna (2005) recycled perlite twice a year for commercial tomato production in bag (18.9L) culture. After the separation of roots from the previous crops, used perlite was then treated with hot water (13.25 L water/18.9L perlite) at temperatures reaching 93.3°C to leach out excess salt and disinfect the medium. This treatment raised media temperatures above limits necessary to kill several fungi and nematodes and significantly reduced media salt (EC, NO3-N, and K were reduced by 43, 50, and 47 per cent respectively) with no noticeable change in physical condition (particle size distribution) over 8 years (which was contrary to common belief that being soft, perlite is sensitive to mechanical compression, which may grind particles to powder). Cleaning and disinfecting used perlite for recycling saved 56 per cent of the cost to replace the media and gave greater marketable yield and heavier tomato fruit than new perlite. The observed yield benefit of perlite recycling was ascribed to the collective effect of salt reduction, media disinfection and the presence of an optimum level of nutrients; it usually takes time to build nutrients to an optimum level in new perlite. Thus, it was concluded that used perlite can be cleaned and disinfected as needed and recycled for many years because it is not organic in nature and physically and chemically stable (Hanna, 2005). Marfa et al. (1993) also found that perlite retains its physical properties for successive crops.

Perlite Insulation
One of the most popular cryogenic insulating systems is perlite, which is heat-expanded volcanic rock.
It is economical and provides excellent insulation in conjunction with a deep vacuum.
It does tend to settle or shift inside the vacuum space as the inner vessel expands and contracts as product is added or withdrawn. The normal vacuum level on a perlite tank is 50–100 μm. If the vacuum level degrades, perlite tanks lose efficiency, but the perlite still retains most of its inherent insulation capabilities.

Superinsulation
This is a lighter, thinner form of insulation that consists of multiple layers of reflective aluminum foil sandwiched between an inert spacer material.
The tank and internal piping are wrapped with these layers to provide radiant heat protection.
An SI-insulated tank has about one-half the heat leak of a perlite tank.
The typical vacuum level is approximately 15 μm, which is much lower than that required by a perlite tank.
If the vacuum degrades on an SI tank, there is a very significant reduction in insulating value with a large increase in venting losses.

All cryogenic tanks have some form of overpressure protection system to protect the vacuum space from overpressurization.
This is either in the form of a lift plate on the top of the tank that is sealed by an O-ring that opens at a positive pressure, or a rupture disc that fails at low positive pressures.
This is required to protect the outer vessel from any leaks that might be created by the piping that is inside the insulation space.
This overpressure protection system is also the primary source of vacuum leaks.
Any evidence of loss of vacuum, such as increased venting or frost spots on the exterior shell, should immediately be investigated and repaired.
This is both for operational efficiency as well as the safety and integrity of the tank itself.

New brewing technologies – Filter aids
There are fundamentally two types of filter aid: kieselguhr or perlite. Kieselguhr, or ‘diatomaceous earth’, comprises silica-based shells of ancient unicellular aquatic microscopic plants called diatoms. Its heat resistance means that it can be used as an insulator, but its abrasiveness means that it has also formed a component of toothpaste and metal polishes. Apart from being widely used as a filter aid to clarify syrups as well as alcoholic beverages, it is used as a filling material in paper, paints, ceramics, soap and detergents. Alfred Nobel found that it is a great absorbant of nitro-glycerine in the manufacture of dynamite.

Huge beds of kieselguhr, between 40 and 50 feet (12–15 metres) deep, are found in Virginia, but also in parts of Germany and in Aberdeenshire in Scotland. The microscopic appearance from different localities differs considerably. The deposits contain varying amounts of organic matter together with sand, clay, and iron oxide, and the raw material is first incinerated (calcined) to destroy organic matter. The successive process stages in rendering bags of kieselguhr in the form needed by the brewer are mining, crushing, drying, calcining, cooling, air classification and packaging.

The interests of purveyors of perlite are looked after by the Perlite Institute (go to http://www.perlite.org/). Perlite is a naturally occurring siliceous rock that, when heated, expands from four to 20 times its original volume. When heated to above 871°C, it pops like popcorn to produce many small bubbles, so perlite is very light and white.

There are many uses for perlite. Its insulating properties and lightness render it valuable as an insulator in masonry and cryogenic vessels. It is used as an aggregate in cement and plasters and for under-floor insulation, chimney linings, paint texturing, gypsum boards, ceiling tiles, and roof insulation boards. Perlite is used as a component of soil-less growing mixes, allowing aeration and moisture retention. It is also used as a carrier for fertiliser, herbicides and pesticides and for pelletising seed.

Apart from clarifying beer, perlite is also used for cleaning up pharmaceuticals, chemicals and water. Like kieselguhr, it can also be used as an abrasive.

WHAT IS PERLITE?
Perlite is made from volcanic rock, which is heated and crushed until it explodes in order to transform the rock into small white pieces. It has medium water retention ratings and low nutrient retention ratings. It is added to soil mixes in order to improve the drainage capability of both soil-based and soilless potting mixes.

Perlite helps insulate plant’s roots from extreme temperature fluxuations. It’s also used as a protective coating on pelleted seeds. Perlite is lightweight, odorless, clean, and easy to handle. It has a pH of 6.6 to 7.5. Add perlite to your soil for plants which need their soil to dry out between waterings, such as cacti or succulents.

Perlite is great for seed starting mixes and blending your own custom potting soil mix
Helps lighten and loosen heavy, compacted soils
White granular pieces that contain about 6 percent water
Perlite has a neutral pH level
Holds nutrients and three to four times its weight in water
Clean, sterile, odorless, and non-toxic
Works as a lightweight sand substitute
Won’t rot or mold
Tends to float to the top of potted plant containers due to its light weight

WHAT IS VERMICULITE?
Vermiculite is magnesium-aluminum-iron silicate. It is an all-natural mineral product that is mined out of the ground and then processed into a soil additive that mainly increases water retention and nutrient retention levels in soil. It looks similar to mica with its layers or stacks, which are suited for trapping water. It has high water retention and high nutrient retention levels. Vermiculite’s water-holding capability makes it perfect as an anti-caking agent in dry pesticides and fertilizers.

Contrary to rumor, vermiculite does not contain asbestos and it is not a type of asbestos. This rumor is due to some vermiculite that happened to be contaminated with asbestos in a mine in Libby, Montana, which was closed in 1990 due to the contamination. Vermiculite from other sources has since been tested and proven to be asbestos free and harmless. The medium is considered safe for commercial and personal use.

Vermiculite is best used for water-loving plants that need their soil to stay moist at all times. Add a healthy scoop of vermiculite to the potting soil of plants that like lots of water.

Great for seed starting or blending your own custom potting soil mix
Helps to lighten and loosen heavy, compacted soil types
Helps soil retain moisture and gives plants nutrients
Mixes easily and well with soil
Clean, sterile, non-toxic, and odorless

COMMON TRAITS OF PERLITE AND VERMICULITE
Perlite and vermiculite are both lightweight sand substitutes for soilless potting mixes which are often used to improve aeration and texture in potting soil and garden soil mixtures. Both are odorless, sterile, disease-free, insect-free, and seed-free. Neither medium will rot, deteriorate, or decompose.

Both mediums are used as an ingredient in soilless potting mixes that are made for the cultivation of plants as well as for seed germination, propagation, hydroponics, containers, and transplants. They are both also commonly used as carriers in dry fertilizers, pesticides, and herbicides to improve coverage.

DIFFERENCES BETWEEN PERLITE AND VERMICULITE
Both perlite and vermiculite are put to use in the garden to improve drainage, prevent compacted soil and increase moisture retention. They are both used in propagation of new plants and for seed starting and cultivation for indoor growing, outdoor growing, and composting. The differences in the way each medium retains water and how much water each medium can retain make them suitable for different applications.

Vermiculite is perfect for plants that enjoy lots of water, such as some irises and forget-me-nots. Perlite dries out too quickly for water-loving plants. The amount of water that vermiculite holds is too much for plants like cacti, succulents, or rhododendrons, which need a well-draining soil. Using vermiculite for plants like these could lead to root rot or death.

COMMON QUESTIONS AND ANSWERS ABOUT PERLITE AND VERMICULITE
ARE VERMICULITE AND PERLITE THE SAME?
Although it’s a common misconception, vermiculite and perlite are not the same. Vermiculite is a silicate material that’s brown or beige in color and has a soft, sponge-like texture. Perlite is harder, is white in color, and is made out of mined volcanic rock.

Vermiculite and perlite also differ when it comes to pH level, which may be a consideration when you’re choosing which to add to your soil. Perlite is slightly alkaline, while vermiculite tends to be closer to neutral.

Vermiculite and perlite do share many qualities. Both products are inorganic, lightweight, and relatively sterile. And of course, both are used as a soil amendment to aerate soil—though perlite provides more aeration than vermiculite. Both perlite and vermiculite are highly porous, making them able to hold water in the soil so it’s available for your plants.

Perlite is a general name given to a naturally formed amorphous volcanic glass that can only be found in specific places in the World.
Perlite can expand 35 times from it’s original volume when softened by heating it from 8500C to 11500C.
This expansion process is facilitated by water found inside the crude rock. When perlite ore is heated up to more than 8500C (160000F), water inside starts to evaporate leading expansion of the softening rock.
The expanded perlite’s exceptional lightweight and physical properties and brought about as small burble like glasses are formed.
Perlite is found in various grey tones and some particles comes close to black color and it is called perlite ore in this state.
Classic perlite: Perlite ore is resized by breaking it into various sizes by filtering it in stages.
Expanded perlite: Classic perlite expands 35 times from it’s original size as a result of exploding due to losing water that’s trapped inside when subjected to high temperatures of fire flame.
Expanded perlite is produced in various fraction sizes according to sector of use.

Expanded perlite can be used in the following sectors;
-Agriculture
-construction
-Filtration
-Insulation
-Textiles
-Fillers & Casting
-Petrol industries
-Cleaning medium

Advantages of Agro perlite
Perlite makes soil ventilated and improves its drainage with its 90% porosity and 60% ventilation porosity.
Perlite increases infiltration, decreases evaporation.
Provides ecoonomical watering procedure.
Doesn’t carry weed seed or illness because it is an organic material.
Perlite doesn’t cause saltness and alkalization problems because of less amounts of soluble ions in it.
Regulates PH values with its chemical buffering properties and notralized pH (pH=6,5-7,5).
Because of its lower electrical conductivity, it protects plant from daily temperature changes.
In non-soiled agriculture activities; it brings advantages of usage with sterilization and usage for 6 years.
It can provide early production. Prevents injuries and losses at seedling roots.
It is organic and therefore it does not decay. It stimulates ventilation and drainage for roots.
Due to its high porosity capacity, It helps plants to absorb minerals and vitamins during watering.
It is economical and renewable. Easily portable due to its lightweight thus requires little labor.
It maintains ambient temperatures in the environment due to its porous and insulating structure.

Nutrition industry.
Filtration of wine, beer and liquors.
Filtration of cooking and vegetable oils.
Filtration of Juices.
Filtration of sugar juice.
Filtration of corn sherbet (glucose/dextrose production).
Chemical and phamaceutical industry.
Distilling antibiotics.
Pectin filtration.
Sulphuric acid filtration.
Phosphoric acid filtration.
Citric acid filtration.
Paper industry.
Sodium silicate (water glass) filtration.
Filtration of paints.
Other Filtration Procedures
Machine oils (regeneration of machine oils)
Filtration of drinkable water.
Filtration of swimming.
Filtration of waste water cleaning.

Perlite is a superior heat and sound insulator due to its porosity.
In buildings; perlite is used to maintain heat and sound insulation in plasters, roofing and floors.
Perlite protects buildings from earthquakes by reducing the dead load of the structure due it’s to lightweight property.
It can not lose its properties when exposed to extreme heat because it is inorganic, it prevents fire from spreading.
Used as an aggregate in lightweight insulating concrete and plaster.
Loose filler in heat and sound insulation.
Used as an insulator in surface tiles.
Special perlite concrete for other purposes rather than plaster.

OTHER USES OF PERLITE:
Used as an additive in the glass and ceramics industry.
Used as a facilitating additive in drilling and cementation.
Insulator in ship decks.
Filtration medium in petroleum and other oils.
Prevents water evaporation in dam lakes and open water reservoirs.
Used as a filler in packaging.
Used as a filler in plastic foams.
Used as a filler in cheap

Benefits
Prevents compaction
Improves aeration and drainage better than vermiculite
Stimulates root initiation and vigorous growth
Holds moisture but does not become soggy
Almost neutral pH
Does not decompose
Free from disease, weeds and insects
Insulates and minimises temperature fluctuations
Inorganic, inert and sterile
No known toxicity or fire hazard

Perlite is an amorphous volcanic glass. It is formed by the sudden cooling of lava. It has a very high water content due to the hydration of the obsidian. It can greatly expand up to 4-20 times its original size when exposed to rapid heating above 870 degrees Celsius.

Metallurgy industry as slag coagulant in iron foundries.
Construction materials industry for production of lightweight plasters, concrete and chemicals.
Food industry as a filtration aid.
Textile industry for stonewash in soft fabrics.
Horticulture industry as a soil amendment.
Agriculture industry as a growing medium for soilless culture.
Various industries to provide cryogenic insulation.

Horticultural Uses for Perlite
Propagation of seedlings and cuttings
Soil conditioning
Hydroponics
Roof deck gardens and eco-roofs
Nursery stock
Hanging baskets
Turf enhancement
Newly planted trees and plants

Expanded perlite is used in a variety of forms to purify, conserve, and protect fresh-water resources from contamination. Perlite is ideally suited to this task because of its physical structure, and because it is derived from a naturally occurring volcanic glass which has been cleaned and sterilized in the manufacturing process.

Commercial Filteraid
Fine expanded perlite is used to strain and purify a variety of liquid solutions, from beverages and juices, to edible oils, pharmaceuticals, or commercial-scale waste-water recovery systems.

Stormwater Filtration Solutions
Coarser grades, with their irregular surface, are useful for capturing fine particulates and oily deposits attached to organic matter. These are used in the filter cartridge media or DOT-approved Media Filter Drains for stormwater applications in order to protect nearby streams and waterways.

Adsorbent Products
Perlite also has adsorbent properties which can be useful for spill kits, and large-scale liquid waste cleanup and disposal. Fine perlite adsorbs as much as 8x its weight, or 50% its volume in water. Performance value will increase with more viscous liquids such as paints, inks and oils. Plus, disposal and transportation fees are minimized due to perlite’s relatively low density and acceptance at local landfills.

PHYSICAL PROPERTIES
Lightweight
Excellent thermal and acoustic insulating properties
Elasticity
Fire resistance
Thermal stability

Lightweight – Versatile – Insulating
Construction Grade expanded perlite serves multiple purposes in construction either as a loose fill masonry insulation, lightweight filler or texturizer, and much more. Individual grains of perlite are comprised of numerous microscopic glass bubbles containing trapped air which gives perlite both its excellent insulating value as well as its light weight. Plus, perlite’s high melting point makes it suitable for fire-proofing composites and other heat-resistant products.

Produced exclusively from a non-synthetic, naturally occurring mineral, perlite is prized from an ecologic standpoint for having a low impact on the environment while being hypoallergenic and free of harmful chemicals. It is a cost-effective way of improving the energy performance of materials and structures without harm to human health or the environment.

Expanded perlite is used as masonry loose fill insulation and sub-floor insulation. It is used for both small-scale residential and large-scale commercial applications. It is found in lightweight, fire-resistant products such as ceiling tiles, door cores, insulating plasters and coatings, lightweight insulating concrete floors, roof-decks and formed products, manufactured stone, acoustical paneling, texturizing agent in paint and stucco, and many other specialty applications.

Benefits of Perlite
Lightweight
Bright white
Flows and dispenses easily
Excellent insulator
Fire-resistant to >1,600 °F
Mixes easily
Will not off-gas or leach chemicals

Transit Mix Perlite Lightweight Concrete

This transit mixing information is presented as a guide to eliminate some of the questions that may arise in the field and to ensure successful construction with perlite concrete.

1. Calculate the volume of a container
Determine the exact volume of a cylindrical container

CALCULATE WET DENSITY

Example:   IMPERIAL    METRIC
Container filled w/ 1:6 mix perlite concrete    15.5 lb    7.05 kg
Weight of container    2.0 lb    0.91 kg
Weight of perlite concrete    13.5 lb    6.14 kg
WET DENSITY
Weight of Perlite Concrete    13.5 lb    7.05 kg

Volume    0.336 ft3     0.00955 kg/m3
Result    40.2 lb/ft3    643 kg/m3
The specified wet density of the 1:6 mix (94 lbs of Portland cement to 6 ft3 of perlite aggregate) is 40.5 ± 3.0 lb/ft3 (643 ± 48 kg/m3).
Therefore, the field test wet density is within the specification range.

This can be done by first weighing the empty container, then filling it level full with water and weighing it again and subtracting the two weights.
This provides the net weight of the contained water, and, if divided by the density of water, the result is the exact volume in the container.
Wet Density
The wet density of perlite concrete as poured is important in the control of the physical properties of the dry concrete and to the yield achieved.
The strength and the insulating value depend on the wet density of the perlite concrete. Heavier density means greater strength and less insulation. To achieve the desired characteristics, the architect or engineer usually specifies the wet density with tolerance of plus or minus 3 lb/ft3 (48 kg/m3).

Field Control
The wet density can be checked for conformance to the architect’s specifications beginning with the first truck load delivered.
Adjustments to the mixing procedure should be made at that time and additional checks made periodically during pouring. The simplest method of field checking wet density is as follows:

2. Calculate the wet density
Fill the container with wet perlite concrete as it leaves the mixer and weigh again. Subtract the weight of the empty container and divide the remainder by the volume as determined in Step 1. The result is the wet density of the perlite concrete in pounds per cubic foot which should be within ± 3 lb/ft3 (48 kg/m3) of the specified value.

Air Entraining Agent
The use of the correct amount of air entraining agent of the proper concentration is of extreme importance in successful perlite concrete construction.
The air entraining agent produces countless tiny air bubbles in the concrete, which improves workability during placement, reduces the density, increases the yield and contributes to the insulation value of the dry concrete.
Air entrained concrete is also more resistant to water absorption.
Care should be taken in mixing perlite concrete to ensure that the proper amount of agent is used. Excess air entraining reduces the strength of concrete.
An even distribution of agent is also essential to produce the desired concrete characteristics. Follow the manufacturer’s recommendation with respect to dosage of air entraining agent.

Super Plasticizer
The use of Super Plasticizer (SP) can reduce the water to cement ratio and enhance the strength of the concrete for mixes with sand.
SP can improve workability, speed finishing, increase strength, conserve cement and help reduce shrinkage and thermal cracking.
Follow the manufacturer’s recommendation for the correct dosage of SP. Do not overdose as this will adversely affect concrete strength and cause segregation.

Placement of Perlite Concrete
Perlite concrete may be placed with a crane and bucket or by pumping. Use of a rotor/stator (progressive cavity) pump—as opposed to a piston pump—is recommended as this type of pump will not place undue pressure on the perlite. Although not recommended, perlite concrete with a density above 1,000 kg/m3 may be pumped using ready-mix pumps if low pressure is maintained. Care should be taken with respect to yield. In addition, a pump hose should be a minimum of 3 inches in diameter. Avoid hose kinking. Hoses should be tied off at each joint.
Yield
Yield is defined as the ratio between the volume of the wet perlite concrete as discharged from the mixer and the volume of perlite concrete aggregate used in the mix. The mix proportions included in the specifications are based on extensive field and laboratory tests and are established for 100% yield. If the correct quantities of material and mixing procedure are used, a 100% yield should result. Yield may vary however as it is affected by job site conditions including mixing time, fineness of aggregate, pumping equipment, height to be pumped, length of hose, etc.
Field Check for Yield
The first step necessary in making a field check for yield is to determine the wet density of the perlite concrete as previously outlined. The wet density and the weight of total ingredients for the mix being used are then substituted in the following formula:

VOLUME OF PERLITE AGGREGATE
Consider a 1:6 mix, with wet density 40.2 lb/ft3 (643 kg/m3)
Example:   IMPERIAL    METRIC
Portland Cement    94.0 lb    42.73 kg
Perlite – 6 ft3 @ 8.0 lb/ft3    48.0 lb    21.78 kg
Water – 12 gallons @ 8.33 lb/gallon    99.96 lb    45.44 kg
Air Entraining Agent – 1.5 pints @ 1 lb/pint    1.5 lb    0.68 kg

Total Weight of Ingredients    243.46 lbs    110.63 kg
YIELD
Weight     243.46 lb    110.63 kg

Wet Density
40.2 lb/ft3     643 kg/m3
Result    6.06 ft3    0.172 m3

% YIELD
Yield     6.06 ft3     0.172 m3

Volume of Perlite Aggregate    6.00 ft3     0.1699 m3
Result    101%    101%
Technical data given herein are from sources considered reliable, but no guarantee of accuracy can be made or liability assumed.

Certain compositions or processes involving perlite may be the subject of patents.

Loss of Yield
If the yield as checked by the wet density is less than 100%, a loss of yield is evident.
A loss of yield may be attributed to a number of factors as previously noted.

However, one or more of the following factors should be checked.

Air Entraining Agent – Be sure that the proper amount is being added to each batch.

Check concentration.

Mixing Procedure and Time – Be certain that materials are added in the proper sequence.
Undermixing will usually result in loss of yield while overmixing can adversely affect the air entrainment.
Water – Check the amount of water being added. After one minute of mixing, properly proportioned perlite concrete often looks too dry.
If extra water is added, yield can be reduced. Hard water will often offset the effect of the air entraining agent and may require adjustment of the quantity of air entraining agent.
Mix Design Data – The proper proportions of materials for various perlite concrete mixes are shown in the table below.
The importance of properly designing and specifying the mix and the proper use of the air entraining agent cannot be overemphasized.

Construction Grade expanded perlite serves multiple purposes in construction either as a loose fill masonry insulation, lightweight filler or texturizer, and much more. Individual grains of perlite are comprised of numerous microscopic glass bubbles containing trapped air which gives perlite both its excellent insulating value as well as its light weight. Plus, perlite’s high melting point makes it suitable for fire-proofing composites and other heat-resistant products.

PERLITE
Derived from volcanic rock, perlite is a natural, lightweight, inert and fireproof rock making it a rock of choice for a wide variety of end uses from cosmetics to construction.

Perlite is a naturally occurring volcanic rock formed from siliceous lava or ash. Due to rapid cooling, the lava or ash solidifies into a glass-like rock. Over tens of thousands of years, surface and ground water infiltrates the rock and becomes trapped in the glass structure. When heated at temperatures from 750 to 1,250°C, perlite expands from four to twenty times its original volume, popping just like popcorn to create countless tiny bubbles. The bubbles created during the heating process account for exceptional physical properties such as low thermal conductivity in perlite and the amazing light weight of expended perlite.

These properties are sought after in many applications from filtration and cosmetics to construction and horticulture.

As a filtration aid, natural, food-grade ATAMAN’S perlites are ideal for filtering wine and fruit juices.
Our range of perlite filter aid is a cost-effective solution for the filtration of wine musts and lees, and is prized by producers of some of the planet’s finest wines.

Perlite is an ideal natural ingredient for cosmetics where gentle abrasion, high absorption and matting effect are desired.
Used in body and face scrubs, perlite is an excellent, eco-friendly alternative to polymer-based microbeads.

Used in the construction industry, perlite is a good thermo-acoustic insulator for cavity walls and a valuable, low density fire retardant additive, ideal for meeting current trends towards lightweight building materials and concrete.

In dry mixes and ready-to-use plasters, perlite is an excellent additive for lightweighting.
In paints, perlite is the most efficient matting agent; and in varnishes it provides matting and transparency.

In horticulture, raw perlite is an environment-friendly soil amendment in growing substrates, where it improves plant growth as well as resistance to insects, disease and environmental stress.

The global perlite market is predicted for high growth over the next few years, fuelled by demand for lightweight building materials, decontaminated filter aids and ecological soil amendment solutions.

High quality filtration is critical for many consumer and life science industries: from beer and wine to sweeteners and edible oils, to blood plasma. Our filtration solutions are based on naturally occurring minerals with exceptional properties such as low density, chemical inertia, high specific surface area and a high level of porosity. Our superior technical services combine these unique functionalities to design filtration substrates that match our customers’ specifications, optimize their process costs and maximize their asset capacity.

Our natural diatomites and expanded perlites have many filtration applications in the food and beverage sector where they are used as process enablers for the filtration of beer, sweeteners, water, wine, juice, tea and edible oils. Our diatomaceous earth products enable brewers to increase beer production and reduce material volumes and waste. Our engineered perlite-based filter aids are designed to optimize the filtration of wine musts where they boost filtration capacity at lower dosages. We offer juice filtration aids that don’t compromise clarity and avoid the use of arsenic; highly permeable adsorbents for waste-oil biodiesel fuels and high-purity grade diatomite filter aids for the biopharmaceutical industry.

OTHER AREAS OF USAGE
– Perlite is used in ceramics and glass industry as additional agent.
– Perlite is used in boring in order to make easier cementation procedure,
– It is used in ship floors coating and isolation,
– Preventing water pollution caused by petroleum wastes and other oil wastes,
– Preventing water loss by evaporation in dam reservoir, open water reservoir,
– Filling material for packaging,
– Filling material for cheap and light plastic furniture production,
– Vibrational fixing,
– In steel constructions it is used as isolation floor from fire.

Perlite

130885-09-5

filtroperlite

Fuyoballoon

Aragats

Nenisanso

Noblite

Perligran

Rokahelp

Stabent

Perfil

Mitsui Perlite

Topco Perlite

Fuyo Lite

Nenisanso 3

Mitsui Perlite B

Ryolex 3

Ceramic Sil 32

Microperl GT 25

Dicaperl HP 610

Topco 54

Silbrico 43-23

P 500 (filler)

Mitsui Perlite Kakoyo 1

Perlite ore is formed by magmatic processes, and water is entrapped in the perlite matrix over geologic time periods. These microscopic pockets of water give perlite ore it’s unique ability to “pop” under proper high-temperature conditions.

What is Perlite?
Perlite is one of nature’s most versatile and efficient minerals. It is formed by molten (magmatic) rock, also known as volcanic glass. Over time, and during formation and cooling, water is absorbed into the raw perlite ore matrix, giving perlite its unique ability to expand when heated.

When perlite ore is heated rapidly in industrial furnaces, the volcanic glass softens, causing the entrapped water molecules to turn to steam and expand the perlite particles—much like popcorn. This can increase in volume up to 20 times its original size.

The expansion process renders the perlite partially transparent, and the resulting complex refraction changes the color from a light gray to bright white. These expanded perlite particles are lightweight and insulated glass bubbles that can hold water and air.

Characteristics of Perlite
Lightweight
Free of organic contaminants
Insulating
Fireproof
Pest-proof

Perlite’s unique characteristics make it an excellent choice for diverse applications, including:

Construction
Perlite’s lightweight and fire-resistance structure make it the ideal product to ensure both construction safety and versatility, from sheetrock to ceiling tiles. It is commonly used as an aggregate in gypsum joint compound.

Horticulture
Perlite helps break up compacted soil, allowing for better water retention, making it useful for professional growers and hobbyists alike.

Cannabis Growing
Cannabis plants, in particular, thrive with perlite because the glass-like bubbles in the heated perlite ensure oxygen is provided right to the plant roots.

Insulation
The air pockets formed when perlite ore is heated and its loose-flowing nature enable it to be a low-density filler that can fit in odd-shaped spaces. Plus, it’s commonly used as cryogenic insulation for gasses.

Industrial
Perlite is lightweight and can safely be used over a wide range of temperatures, making it useful for a variety of industrial applications, including high-temperature insulation, molten metal topping, lightweight fillers, and more.

Filtration
Crushed expanded perlite particles present a maze of microscopic pathways that can be used for filtration and clarifying a wide array of liquids, beverages, and pharmaceutical products.

Perlite as a Construction Filler
Construction Filler
Expanded perlite’s high insulating qualities, light weight, and versatility make it an essential part of the construction industry for loose fill insulation and lightweight insulating concrete. It is the ideal construction aggregate filler for masonry fill insulation, roof decks, floor systems and other significant areas that need insulation.

Construction Aggregates
Perlite and Gypsum Products
Perlite plaster aggregate mixed with gypsum provides an ideal base coat for plaster for interior walls, membrane fireproofing to the underside of the floor and roof assemblies, and for structural steel members.

Perlite and Joint Compounds
Joint compounds produced with perlite are lightweight and easy to work with. Perlite also improves the bonding properties and provides greater uniformity.

Cavity and Block-fill Perlite
There are countless reasons why nearly 50% of manufactured expanded perlite is used as a construction filler. Some of the reasons include high insulating qualities, light weight and its adaptability. But what it really comes down to is economics and the monetary savings of using perlite. The return on investment when using expanded perlite for loose-fill cavity and construction block-fill can be reached rather quickly as reductions in energy consumption are quickly achieved. In addition, businesses are saving money every day because expanded perlite is light weight, pours easily and efficiently into place without a general investment in equipment and experience. Expanded perlite for loose-fill cavity and construction block-fill insulation can be poured straight into the cavity walls or a self-dumping hopper. This allows for easy guidance and smooth operation along the wall to direct the moving perlite into the cores of the cavity, mitigating any voids and air pockets.

For more information on R and U-Values for Concrete Block assembles with and without perlite Download our Perlite Loose-fill Masonry Insulation Guide.

Dicaperl’s perlite masonry fill insulation is surface treated to produce water repellency from both liquid and vapor phase. Dicaperl’s masonry fill insulation may be used to advantage in insulating masonry block, cavity, and veneer walls. For more information on the advantages of perlite masonry fill shown below, visit Dicaperl Insulation:

Energy Saving Insulation
Fills All Voids and Cavities
Noncombustible
Inorganic
Easy installation
Economical

Perlite Uses and Applications as a Construction Filler
Nearly 50% of expanded perlite worldwide is used by the construction industry, largely in part because of its versatility. Some construction applications include:

Aggregate in lightweight insulating concrete
Insulating and lightweight plaster
Loose fill insulation material for concrete masonry blocks, cavity walls, in residential homes
Fireproofing sprays
Chimney fills
Interstitial floors
Acoustical sprays
Green roof soils
Fireproof insulating door cores
Plaster Aggregate
Textured paint
Decorative stone
Tape joint compound
Cultured marble
Ceiling tiles
Underslab insulation
Cement stucco
And more

Perlite in Lightweight Formed Products
Ceiling Tiles, Pipe Insulation, Roofing Board, & Fire-rated Door Cores
Ceiling Tile ManufacturingThe largest use of perlite ore in North America is its expansion and use in ceiling tile manufacturing.

Benefits of Expanded Perlite for Ceiling Tiles
Some Ceiling Tiles Contain up to 70% by Weight of Expanded Perlite because of its Numerous Benefits

Lightweight
Fire resistant
Improved acoustical properties
Reduced water absorption
Energy savings
Wet-Felted Acoustical Ceiling Tile and Panels
Expanded perlite (40-50%) is also present in a unique wet-felted acoustical tile and ceiling panel composition. It has been presented that expanded perlite is favorable in the production of ceiling tiles and panels to reduce the tendency to retain water in a composition containing expanded perlite, mineral wool, and a secondary binder such as starch or clay. It has been found that an acoustical tile composition containing wet-felted, mineral fiber and lightweight expanded perlite help to promote an efficient installation, anti-sag performance and prevent mold and mildew

Pet Litter
Perlite: The “Pur-fect” Solution to the Pet Litter Problem
Pet litterPet litter manufacturers were met with a problem: a survey of customers revealed a common frustration was that kitty litter weighed too much, and it was difficult to purchase, use, and replace.

Perlite was the perfect solution to this heavy problem because it keeps the mass of the product without extra weight. Now, lightweight cat litter made with perlite can weigh 50% less than standard.

Expanded perlite is extremely absorbent and provides the ideal complement to other ingredients in pet litter—such as clays, and odor control elements—without interfering with the effectiveness of either. It can also be sized to fit the application, which is critical for cat litter and other applications where particle size distributions affect the finished product specifications.

Benefits of Expanded Perlite for Ceiling Tiles
Some Ceiling Tiles Contain up to 70% by Weight of Expanded Perlite because of its Numerous Benefits

Industrial Uses and Applications of Perlite
Ladel Topping Applications
In ladle topping applications, expanded or unexpanded granular ore forms of perlite are added to molten metal pouring ladles. Most often the ore form is used which reacts with slag in the ladle to allow easy removal of the slag layer. In cases where it is desirable to maintain a metal temperature in a ladle, the expanded perlite layer forms an efficient insulating blanket.

slag coagulant material is manually added to the surface of molten metal after it is poured into a ladle. Slag that is present on the molten metal adheres to the perlite and floats for removal. With the removal of the combined perlite and slag, the metal is clean and ready for casting.

Ceiling tiles
Pipe insulation
Roofing board
Fire-rated door cores
High-temperature insulation
Molten metal topping
Joint compound, spackling
Cryogenic insulation
Filtration
Lightweight fillers
Decorative stone
Fireplace chimneys
Specialty stoves
Wood fired bread and pizza ovens
Perlite Filler Size and Shape
Industrial perlite ore grades are milled accordingly to fit your industrial requirements (see perlite ore lind card). Expansion of perlite ore grades is manufactured in 10+ locations across North America. Perlite microspheres, one form of expanding perlite, form from a unique milling process consisting of broken, expanded perlite particles that form flake-like, flat particles with an interlocking, three-dimensional structure. This structure helps reduce shrinkage upon drying or curing, maintaining the physical dimensions of the host material. Typical uses for perlite glass flake fillers are:

Water-based construction compounds
Paints
Asphalt
Concrete
Plaster
Resin-based castings

Horticultural Perlite
For Commercial Growers, Landscapers, and Home Gardeners
HorticultureHorticultural perlite is a lightweight, non-organic, soil substrate that provides a number of important benefits to commercial growers, landscapers, and home gardeners. Among the many benefits and reasons to include horticultural perlite in your commercial growing mix, above all else, Dicaperl maintains a quality above the industry norm by registering and listing their soil substrate product as an Organic Input Material (OIM) with the California Department of Food and Agriculture.

Perlite’s Horticultural Benefits
Some of the benefits of perlite use in horticulture are:

Breaks up Compacted Soil
Perlite can be used to break up compacted soil for better water drainage.

Aerates Soil
The high displacement and lightweight volume capacity of expanded perlite provide room for air and water, preventing over-watering and allowing proper drainage.

Inorganic
Because it is inorganic, perlite is stable and doesn’t decompose or break down.

Neutral pH
Perlite’s pH range is 6.5 to 7.5—the ideal zone for most plants to absorb nutrients.

Light Weight
Perlite is lighter than grit or sharp sand, pumice, or other aggregates—which can also be used to improve drainage in a garden bed. Adding Perlite to your growing media makes for lighter, easier to handle products for manufacturers, and makes it easier for home gardeners to work with.

Sustainable
Perlite is one of nature’s most versatile and efficient minerals. It is formed by molten (magmatic) rock, also known as volcanic glass. It acts as a lightweight, non-organic, soil conditioner for commercial growers, landscapers, and home gardeners alike, providing numerous benefits. See for yourself how perlite is one of the most sustainable soil substrates on the commercial market.

Common Horticultural Perlite Uses
There are a variety of applications, including:

Propagating
Potting Soils
Stadium turf
Golf course turf
Lawns
Hydroponic crops (tomatoes, bell peppers, chillies, and more)
Trees and shrubs
Bulb and tuber storage
Garden beds

Fillers: Plastics & Films
Fillers: Plastics & FilmsWith a range of particle sizes and grades, ultrafine perlite microspheres offer advantages as a filler for plastics and films, including:

Weight reduction
Shrink and/or crack resistance
Low volume-based cost compared to binders and some other fillers
Whiteness
Impact resistance
Machinability and ease of sanding
Nail and screw holding ability
Flexural strength modification
Gloss and sheen control
Pigment extension
Inertness and non-toxicity
Water and/or air permeability
Fire resistance
Insulation
Modification of acoustic properties
Perlite ultrafine fillers have been used in a number applications for many years, including:

Silicone rubber
Synthetic rubbers
Natural rubbers
Thermoplastic resins
Decorative home and garden fixtures
Thermosetting resins
Paint
Coatings
Polishes
Cleansers

Perlite Filter Aids

Perlite’s low density, availability, performance, cost, and environmental footprint make it an essential filtration aid in many industries.

Benefits of Perlite Filter Aids
Ease of Application
Experience in a variety of applications has shown users can easily switch their current filtration media to a perlite filter aid economically and without sacrificing performance.

Inert State
Perlite is naturally inert, so no tastes, colors, or odors are transferred to the filtered product.

Insoluble
Perlite filters are virtually insoluble in mineral and organic acids at all temperatures. Solubility in strong alkaline solutions varies, depending on temperature and contact time.

Usable with Standard Equipment
It can be used with either pressure or vacuum filtration equipment.

Less Weight, Same Volume
Perlite filter aids can weigh as much as 50% less than the other types of filter media, allowing for the same volume of filter cake with much less weight.

One-to-One
Use perlite on a one-to-one volume basis to replace another filter aid.

Anti-Caking
Perlite filter aids are also revered for the end of the filtration process; the filter cakes remain porous and do not compact.

Applications of Perlite Filter Aids
Food and Beverage
Juices
Beer
Wine
Sweeteners
Vegetable oils
Wastewater treatment
Pharmaceutical
Enzymes
Antibiotics
Epsom Salt
Industrial
Water treatment
Sizings
Oil and solvent recovery
Greases
Chemicals
Inorganic & organic chemicals
Resins
Polymers
Brine
Adhesives
Fertilizers
Waste disposal
Paint and Coatings
Waxes
Oils
Varnish
Gyms
Shellac
Wastewater treatment
Environmental
Stormwater filtration
Ecology embankments
Media filter drains
Wastewater treatment

Perlite as Insulation
With its Light Weight and Naturally Heat-resistant Composition, Perlite is Valued as a Superior Insulator
InsulationThere are numerous benefits of using perlite for insulation, including:

Building and Masonry Fill
Energy Savings
Because of its unique closed cell structure, Dicaperl’s masonry fill insulation can drastically reduce heat transmission through masonry walls. The efficiency of perlite loose fill insulation has led to its almost exclusive use in insulation tanks containing liquified gassed where temperatures of -320°F and below must be maintained. Thermal performance tests show significant energy savings when perlite is used to fill cavities in concrete masonry structures. These tests have determined that perlite masonry fill insulation can be more effective than polystyrene beads, polyurethane foam, polystyrene inserts, vermiculite core fill insulation, and foamed-in-place insulation.

Fills All Voids and Cavities
In addition to its closed cell structure, a key to perlite’s performance is its ability to seek out and completely fill all crevices, voids, and mortar areas in a masonry wall without bridging. This flowability characteristic of perlite masonry insulation assures a completely and efficiently insulated wall. In addition, this flowability feature enables the masonry contractor to install several courses of block before pouring insulation into cavities and/or core holes. Because perlite masonry fill insulation is non-settling and will not compact under its own weight, it is a permanent insulation that will last the life of the structure.

Cryogenic Insulation Services
CryogenicSuper-cold cryogenic fluids, such as hydrogen and helium, are typically stored in double-walled vessels with perlite-filled annular spaces. Cryogenic perlite is a finer grade of perlite with consistencies similar sand. At Dicaperl, we provide cryogenic insulation services and produce an extremely lightweight expanded perlite suitable for use in industrial storage vessels.

Cryogenic Perlite Advantages
Very low thermal conductivity: λs = 0.034 – 0.042 W/(m.K)
Very low moisture content
Free from organic materials
Safe for human health
Excellent thermal properties
Low cost
Easy to install
Noncombustible
Meets fire regulations
Doesn’t shrink, swell, warp or slump
Pest Proof
Cryogenic Insulation Services
Low-temperature storage tanks
Cold boxes
Test Chambers
Food Processing
Double-walled vessels and pipes

Perlite, also called pearlstone, a natural glass with concentric cracks such that the rock breaks into small pearl-like bodies. It is formed by the rapid cooling of viscous lava or magma. Perlite has a waxy to pearly lustre and is commonly gray or greenish but may be brown, blue, or red.

Perlite is not a trade name but a generic term for naturally occurring siliceous volcanic rock. The distinguishing feature which sets perlite apart from other volcanic glasses is that when heated to a suitable point in its softening range, it expands from four to twenty times its original volume.

This expansion process is due to the presence of two to six percent combined water in the crude perlite rock. When quickly heated to above 1600 F (870 C) the crude rock pops in a manner similar to popcorn as the combined water vaporizes and creates countless tiny bubbles in the softened glassy particles. It is these tiny glass-sealed bubbles which account for the amazing lightweight and other exceptional physical properties of expanded perlite.

The expansion process also creates one of perlite’s most distinguishing characteristics: its white color. While the crude perlite rock may range from transparent to light gray to glossy black, the color of expanded perlite ranges from snowy white to grayish white.

Expanded perlite can be manufactured to weigh from 2 lbs/ft3 (32 kg/m3) to 15 lb/ft3 (240 kg/m3) making it adaptable for numerous uses, including filtration, horticultural applications, insulation, inert carriers and a multitude of filler applications.

Since perlite is a form of natural glass, it is classified as chemically inert and has a pH of approximately 7.

Perlite is mined and expanded all over the world. The United States is estimated to be the largest consumer and producer of crude and expanded perlite. However, there is very strong world wide production and consumption of perlite. Other leading countries producing perlite include China, Greece, Japan, Hungary, Armenia, Italy, Mexico, Philippines, and Turkey.

Basic Facts About Perlite:

Origin and Characteristics

Perlite is not a trade name but a generic term for naturally occurring silicous rock. The distinguishing feature which sets perlite apart from other volcanic glasses is that when heated to a suitable point in its softening range, it expands from four to twenty times its original volume.

This expansion is due to the presence of two to six percent combined water in the crude perlite rock. When quickly heated to above 1600°F (871°C), the crude rock pops in a manner similar to popcorn as the combined water vaporizes and creates countless tiny bubbles which account for the amazing light weight and other exceptional physical properties of expanded perlite.

This expansion process also creates one of perlite’s most distinguishing characteristics: its white color. While the crude rock may range from transparent light gray to glossy black, the color of expanded perlite ranges from snowy white to grayish white.

Expanded perlite can be manufactured to weigh as little as 2 pounds per cubic foot (32kg/m3) making it adaptable for numerous applications.

Since perlite is a form of natural glass, it is classified as chemically inert and has a pH of approximately 7.

Formed from viscous lava, perlite is a volcanic glass of rhyolitic composition that contains between 2 and 5 percent water. Most volcanic glasses contain some water, including obsidian (less than 1 percent) and pitchstone (up to 10 percent). Although the exact formation process for perlite is debated, it is theorized that the lava that formed perlite was deposited and cooled near the surface and hydrated over time. Pumice is closely related to perlite in composition but, because of the explosive way in which pumice forms, the rapidly cooling lava entrains air and becomes much less dense than perlite.

Perlite is mined by employing heavy machinery to rip or cut the material out of the earth, or by precise blasting. After extraction, the material is crushed and sized into marketable fractions. Then it goes to another plant where it is expanded, or “popped.” When heated, the water content of perlite reacts, and the perlite pops like popcorn. Perlite popping produces a lightweight product that is up to 40 times less dense than the original material.

In primary usage, perlite competes with other lightweight construction materials, like pumice, exfoliated vermiculite and expanded clay and shale. Each of these lightweight materials has its pros and cons, depending on the application, and each has retained certain niche markets. Perlite is especially favored in lightweight construction products, fillers for paints and joint compounds, horticultural soil blends and certain filtration applications. In addition to these primary markets, perlite is used for concrete aggregate, insulation, plaster aggregate and stone washing in laundries. In most offices or other locations with a “dropped” ceiling, the ceiling tiles are probably made primarily of perlite.

PERLITE: volcanic glass that has a concentric structure, appears as if composed of concretions, is usually grayish and sometimes spherulitic, and when heated expands to form a lightweight aggregate used especially in concrete and plaster and as a medium for potting plants

Perlite
Perlite is an amorphous volcanic glass (SiO2) that has relatively high water content, typically formed by the hydration of obsidian. Perlite has the unusual characteristic of expanding and becoming porous when it is heated. It can expand to as much as twenty times its original volume. Expansion occurs when the glassy lava rock is heated to 1600 degrees F (871 degrees C) and the water molecules trapped in the rock turn into vapor causing the rock to expand. (This is the same principle as the water in popcorn that causes the kernel to pop when it is heated.) Before it is expanded, perlite is commonly gray, but can also be green, brown, blue or red. After it has been heated, perlite is typically light gray to white.

Description
Perlite is an amorphous volcanic glass (SiO2) that has relatively high water content, typically formed by the hydration of obsidian. Perlite has the unusual characteristic of expanding and becoming porous when it is heated. It can expand to as much as twenty times its original volume. Expansion occurs when the glassy lava rock is heated to 1600 degrees F (871 degrees C) and the water molecules trapped in the rock turn into vapor causing the rock to expand. (This is the same principle as the water in popcorn that causes the kernel to pop when it is heated.) Before it is expanded, perlite is commonly gray, but can also be green, brown, blue or red. After it has been heated, perlite is typically light gray to white.

Relation to Mining
Perlite is mined using open pit methods such as ripping or blasting, or both. If the perlite is soft and friable, brecciated, or extensively jointed, ripping is employed with significant cost savings. Blasting is required where perlite cannot be readily broken using rippers, but care must be taken to achieve fragmentation without production of excessive fines or oversized material. Once broken and sometimes crushed, the perlite is loaded on trucks or conveyor belts by front-end loaders, excavators, or scrapers for transport to the processing plant. Selective mining is used to minimize associated rhyolite or obsidian. If perlite textures vary, it is often blended to produce consistent milling characteristics and to meet market specifications.

The United States is one of the world’s largest producers and consumers of crude perlite and expanded perlite. A number of western states including Utah and Oregon produce perlite, with New Mexico being the most important perlite-producing state. Other countries that produce large amounts of crude and expanded perlite include China, Greece, Italy, Philippines, Mexico and Turkey.

Uses
The majority of perlite is used in construction products, mainly ceiling tiles and roof insulation products, but also as refractory bricks (a refractory brick is a brick designed to withstand very high temperatures), pipe insulation, and filling in masonry block construction. Perlite is also used as an insulator to reduce noise and, since it is non-combustible, it also improves the fire resistance of different construction components in buildings. Perlite is an important commodity in the horticulture industry where it is mixed with soil. The addition of perlite to soil increases the amount of oxygen held in the soil, as well as the amount of water retained by the soil. This represents approximately 10% of annual perlite consumption.

Perlite is an inorganic siliceous ore. The distinguishing feature of perlite is its expansibility of approximately 10 times when heated over 800 C°. Perlite contains crystallised water that is evaporated when heated creating numerous microscopic air hollows that provide the insulation’s characteristics. The LBD (Loose Bulk Density) of dry perlite is approximately 1-1.1tons/m³ whereas the LBD of the expanded perlite may have 60-500Kg/ m³ according to the end usage.

Chemical Composition

• 70–75% silicon dioxide: SiO2
• 12–15% aluminium oxide: Al2O3
• 3–4% sodium oxide: Na2O
• 3–5% potassium oxide: K2O
• 0.5-2% iron oxide: Fe2O3
• 0.2–0.7% magnesium oxide: MgO
• 0.5–1.5% calcium oxide: CaO
• 3–5% loss on ignition

USES OF PERLITE

The uses of perlite can be divided to three major categories. Construction applications, agricultural applications and industrial applications.

Construction applications
The major market for expanded perlite is the construction market due to its high thermal and sound insulation characteristics and its low bulk density. Perlite does not deteriorate through time or climate changes and also is practically inflammable. The applications of perlite in the construction market are:

• In mortars (either cement based or gypsum based)
• In lightweight concrete
• As a loose filling insulation

Agricultural applications
Expanded Perlite is widely used in the agricultural market as an ingredient in peat soil providing the appropriate conditions for leafy and flowering pots. Expanded Perlite provides the ideal ratio of air and water but also the required drainage.
Expanded Perlite has also been used in Hydroponic growth systems providing excellent results due to it’s neutral PH and the low saturation compared with other materials.
Industrial applications
With its unique characteristics perlite has wide and diversified usages in the industry some of them are:

• Unexpanded and expanded perlite is also used in Foundries. Unexpanded perlite is used as a mean to attract all the impurities. Expanded perlite is used as an insulator for reducing heat losses and is also used for high quality alloys.
• Another use of expanded perlite is for the absorption of waste oils and oil spills in the sea.
• Perlite is also used in soap, toothpaste and detergents due to its abrasive characteristics.

Perlite is used in casting of iron and steel for insulation of level of metal melt in casting ladles and moulds. The expanded perlite with a grain size of up to 5 mm shall be thrown in paper or polypropylene bags onto the level of metal melt. When touched a fused metal the bag explodes and burnes down, whereas expanded perlite get widespread over all the level of metal melt. A formed insulating film prevents fast cooling of the molten metal. Admixtures and slag get transformed into a profitable part, whereby the quality of the base metal improves.

Cryogenic Applications for Insulation
perlit-tiefkuehlisolierung

Because of its unique properties, perlite is applied for insulating of cryogenic and low temperature storage tanks, where super-cold gases may be stored or transported in a liquid state. So perlite is used in the shipping industry for the construction of Liquefied Natural Gas (LNG) tankers as a material for tank insulation as well as in refrigeration as filling for coolers in the air separation plants.

Perlite is the most commonly used filter aid that meets all requirements. Compared to other filter aids it is characterised by product’s harmlessness in terms of health and ecology: it has a neutral pH value between 6,5 and 7,5, is chemically inert, highly stable and almost insoluble. Moreover, no tastes, odors and colors are imparted. Perlite filter aid is being utillized in a wide variety of applications like chemical, pharmaceutical and food-related industries. For instance, it is widely used in the clarification of apple juice concentrate as soon as in the brewing of beer and production of vegetable oils and different soft drinks.

Agriculture and horticulture

Mixed with soil, perlite has a positive effect on the ground – as it protects against excessive compaction significantly improving the aeration, perlite also prevents waterlogging. Perlite encourages an uniform distribution of the root structure around the plant material. It protects the roots from freezing and overheating. Without being mixed with soil perlite has successfully proven itself to be an outstanding propagation substrates for plants as well

A classical application for perlite is its use as masonry fill in the hollow cores of masonry cavity walls and roofs. The loose granules are used for thermal and acoustic insulation as well as for height compensation. Furthermore, perlite is applicable to use as lightweight aggregate in plaster, plaster base, mortar, screeds. A number of heat insulation products (insulating boards, building panels) are made of perlite.

UTILIZATION FIELDS OF EXPANDED PERLITE

HEAT ISOLATION OF CRYOGENIC VESSELS
Perlite is used for storage of liquid gases (-270 C) to keep their temperature in needed values for storing them as liquid gases. Perlite is filled between double walls of vessels or tanks in atmosphere pressure and vacuum.
Liqufied petroleum gas (LPG)
Liqufied natural gases (LNG)
Liquid nitrogen and ammoniac
Liquid progane, ethane and methane
Liquid oxygen
Liquid noble gases, propellant gases (propellans), refrigerant gases (refrigerant etc.)

HEAT ISOLATION OF DIFFERENT FURNACE AND SYSTEMS
Perlit is used for prohibiting heat transfer to external environment(heat loss) for furnace with higher temperature working conditions.
Free backfill is made outer surface of the furnace. (between double walls)

REFRACTORY BRICK PRODUCTION
Perlite is used in production of bricks and soil mixtures as addition agent for vessels, cementation, heat processing and in melting furnace.
Fuel saving can be reached with refractory blocks that produced by clay and calcium cements connecting to each other and that brings higher heat isolation with lighter bricks.
Ceramics bounded perlite refractory bricks.
Aluminum phosphate bounded perlite refractory bricks and concrete.
Perlite refractory soil mixture

CASTING INDUSTRY
Used as metallurgical flux in casting industry.
Used as additional agent for casting sand.
Protection of melted metal in melting pot.
Protection of heat losses from metal ingot that going Rolling mill or forging.
Sinter control of melted metal in iron-steel industry.

CONSTRUCTION (HEAT ISOLATOR SOIL MIXTURES AND PLASTERS)
Perlite has heat and sound isolation properties because of its porous structure. Perlit is used in plasters, roof coatings, schappe and also for heat and sound isolation purpose between floors. Because of lightness it decreases dead load on building and protects buildings from earthquake.
It doesn’t lost its properties in higher heat conditions and prevents spread of fire. Because it is anorganic material.
Usage in Construction Sector;

Perlite plasters
Light isolation concrete with perlite aggregates. (Concrete and plaster bounders)
Light structural elements with perlite aggregates.
Perlite used as weak filling material for heat and sound isolation
Perlit used as heat and isolator in flor surfaces.
Perlite concrete used bounding agents rather than cement and plaster, for special purposes.

AGRICULTURE
Perlite is used in ventilation of soil, rooting with cutting, improving water holding property of soil, helping agent for spreading droppings, improving physical properties of decoration or flowerpot soil properties as subsrate material.
Perlit Usage in Agriculture;
Perlite makes soil ventilated and improves its drainage with its %90 porosity and %60 ventilation porosity.
Perlite increases infiltration,decreases evaporation. Provides economical watering procedure.
Doesn’t carry weed seed or illness because its an inorganic material.
Perlite doesn’t cause saltness and alkalization problems because of less amounts of soluble ions in it.
Regulates pH values with its chemical buffering properties and notralized pH (pH= 6,5-7,5)
Because of its lower electrical conductivity, it protects plant from daily temperature changes.
In non-soiled agriculture activities; it brings advantages of usage with sterilization and usage for 6 years. It can provide early production.
Prevents injuries and losses at seedling roots.

USAGE FOR FILTRATION
Perlite is used for separating solid material from solid-liquid mixture, providing luminous and fast filtrate with easy filtration in cold and hot environment.

In food industry
Medicine and Chemical Industry
Other filtration procedures

TEXTILE SECTOR
Perlite is inert and water insoluble material because of its stable behavior. It is used as bleaching agent in textile sector. It doesn’t have harmful effect on health because it is an sterilized material. Perlite is easy to use doesn’t cause abrasion, doesn’t cause blocking and its light.

Some common applications for perlite as an insulator in buildings include:

in the cores of hollow-masonry unit walls;
in the cavities between masonry walls;
between exterior masonry walls and interior furring;
for under-floor insulation and the leveling of old floors. In this application, perlite insulation is poured on the original floor surface, screeded to proper depth, covered with corrugated cardboard or lightweight boards, and a layer of oil paper;
in ceiling tiles;
as fireproofing around chimneys, doors, rooms and safes; and
for roof decking.

Agro-perlite is a volcanic soil with a chemical composition that improves the soil quality upon addition. When perlite is added to the soil, it reduces the ripening period of the crop by 20% and increases output yield by 50%.
The recommended usage of perlite with soil varies from 1:3 to 1:4. It majorly depends on the soil type. For clay and sand-type soil, it is majorly used in a tight proportion in order to allow breathing. It also prevents pest and fungi development. Agroperlite holds fertilizer in close combination, which helps the plant or crops to grow conveniently.
Agro-perlite is used as a soil regulator or as an agent to decrease water losses. It can change the physical properties of greenhouse soil instead of chemical properties. In greenhouse with sub-irrigation and dripping irrigation application, by pouring 4-5 cm of course grain sized perlite, water usage can be decreased to half.
For balcony and terrace gardens, it is preferable to use lightweight horticultural soil to facilitate moving and arranging of the flower-pots with 50% Perlite + 50% peat moss + fertilizer, which is one of the ideal mixtures for use in the cultivation of the domestic plants.

Perlite | [ˈpər-ˌlīt] |
CATEGORIES: MINERALS
Perlite Skincare Benefits:

Oily Skin Treatment

Perlite is a naturally derived mineral that is extracted from volcanic rock. In skincare, perlite is used for its ability to absorb moisture without hindering the skin’s natural breathing ability. Aside from facial masks, this non-renewable resource is most commonly found in cosmetic powders and may contribute a matting effect to reduce the look of oily skin. Additionally, perlite’s spherical qualities possess gentle exfoliating properties, making it an environmentally safe alternative for polyethylene beads

PERLITE BASED SOILLESS CULTURE SYSTEMS: CURRENT COMMERCIAL APPLICATIONS AND PROSPECTS
Authors
S. Grillas, M. Lucas, E. Bardopoulou, S. Sarafopoulos, M. Voulgari
Abstract
The use of soilless culture has substantially increased during the last decade as it contributes to the intensification of horticultural production and provides high crop yields even in areas with adverse growing conditions. Market evidence of extensive use of perlite with soilless culture solutions suggests that perlite is a suitable growing medium with distinct properties. Perlite provides improved aeration and drainage and optimum moisture retention and nutrient availability when compared to other substrates. Experimental results show that perlite enriched with clinoptilolite provides improved yield of some crops (e.g., flowers). In Europe, perlite is a well-established substrate in the sophisticated Benelux market of vegetable and flower cultivation. Rapid expansion of perlite soilless culture systems (growbags) is observed in the Mediterranean region in the last 5 years. Spain is the pioneer among the Mediterranean countries in the commercial use of perlite, mainly for vegetable productions (Almeria and Murcia regions).
Today, around 1,500 hectares (ha) use perlite (48% of the total) and in three years this area is expected to be doubled.
Similarly, but on a smaller scale, are the growth patterns observed in other Mediterranean countries, such as Greece and the North African countries.
A different market status exists in North America, where perlite is largely used as an essential component of peat-based substrates, called “peat-lite mixes” for floriculture.
The high porosity of this substrate helps to control the water holding capacity and aeration of the substrate.
In the last three years the cultivation in these “peat-lite” mixes has increased at 7% per year approximately.
The Pacific Rim region presents promising perspective for the development of soilless culture and use of perlite which is locally produced.
The largest perlite suppliers promote the transfer of technical and commercial know-how and are in a position to offer integrated solutions to producers on soilless cultivation with perlite ensuring at the same time the availability of the perlite substrate near the cultivation areas, thus eliminating transportation deficiencies and reducing installation costs.
With regards to future growth of soilless culture with perlite substrate, it is important to commission additional research projects for vegetables and flowers grown in perlite, with the objective of building further confidence on the advantages of this type of cultivation.

PERLIGRAN® – the perlite for horticulture
First-rate quality for substrates and hydroponics
Whether as mineral supplement or as a pure medium, PERLIGRAN®, made from pure and natural perlite, enables the optimal growth of a multitude of delicate roots, reliably creating ideal conditions for highly profitable growth of vegetables, herbs, and ornamental plants.

Five varieties for healthy root growth
The PERLIGRAN® products
100 % natural PERLIGRAN® creates the best conditions for strong, healthy root growth as a basis for vigorous plants and high yields.

Make your selection of the desired screening grade and grain size. For your reference: the core application of PERLIGRAN® Classic is soil improvement of substrates and wet, heavy soils in landscaping. PERLIGRAN® Premium is the high-end product that sets international standards, not least in hydroponics. PERLIGRAN® Organic is the organic substrate additive that adapts the growing conditions of plants to their natural environment.

Lightweight Gypsum Based Materials: Methods of Preparation and Utilization

Although gypsum is one of the most environmentally friendly building binders, its use in the buildings is relatively limited and therefore the broadening of the gypsum product portfolio is desirable. One possibility is the development of the lightweight gypsum materials with better thermal insulation properties, attractive acoustic properties and also lower transportation costs.
The lightweight gypsum materials can be used in a similar way as an aerated autoclaved concrete (AAC), whose energy consumption at production is several times higher.
The main methods of the preparation of gypsum-based lightweight materials are described and compared.
Gypsum can be lightened indirectly by the lightweight filler or directly.
In the directly lightened materials, the pores are introduced into the gypsum material either by some chemical reaction producing gas or by the help of surface active substances.
For the chemical lightening a large scale of waste products can be used. Lightening by the help of waste stone powder is described in detail.
The materials with the properties comparable with the properties of AAC were prepared.
Their bulk density was under 600 kg/m³, compressive strength was about 2 MPa and coefficient of thermal conductivity was under 0.2 W/m.K.
Lightweight gypsum materials can be used as a thermal insulating blocks, for the lightweight gypsum boards, partitions blocks, lightweight fire-resistant plasters or thermal-insulating plasters.

The effect of moisture content on sound absorption of expanded perlite plates
Abstract
Expanded perlite is a porous, lightweight, fire resistant and moisture retaining material with sound and thermal insulation properties. In this research, acoustical behaviour of plates made of expanded perlite was studied experimentally. Since these plates are used for sound absorption, the acoustical parameter selected for this study is “sound absorption coefficient”. Preliminary experiments indicated that moisture reduced the sound absorption coefficient on plates and there is not much significant difference between the dry and 50% humid conditions. However, there is a significant difference in acoustical properties for the 50-95% humid conditions. Thus, this interval was studied in detail. A number of expanded perlite plates having different mixtures were prepared and tested. It was observed that, coating the expanded perlite particles with sodium silicate increased the moisture resistance. and the addition of mineral fibres into the mixtures increased the strength and sound absorption coefficient of the plates.
Keywords
Perlite
Building materials
Acoustics
Sound absorption coefficient
Duct acoustic properties

Expanded perlite exhibits very low thermal conductivity, low sound transmission, high fire resistance, a large surface area and controllable moisture retention and drainage. It is chemically inert, sterile, non-toxic and non-fibrous, free of organic impurities, and has a neutral pH. Regarded as an essentially “environmentally safe” building material, perlite is incredibly versatile and is used in a wide range of products and processes in industry—as a soil amendment, as insulation, as a filter aid, as lightweight concrete aggregate, liquid waste stabilizer, and many more.

Perlite ore is a glassy volcanic rock with a vitreous, pearly luster and a characteristic concentric or perlitic fracture. Closely related to pumice, it differs from other volcanic glasses principally in its combined water content, which produces the unusual characteristic of “popping”—expanding up to 20 times its original volume when exposed to rapid, controlled heating. Rapidly heating perlite ore to temperatures of about 900°C (1,700°F) softens the volcanic glass, causing entrapped water molecules in the rock to turn to steam and expand the particles like popcorn. The resulting expanded particles—actually clusters of minute glass bubbles—are spherical in shape, usually fluffy or frothy, highly porous due to a foam-like cellular internal structure, and have a very low density.

The expansion process also creates one of perlite’s most distinguishing characteristics: its white color. While the crude rock (ore) may range from transparent light gray to glossy black, the color of expanded perlite ranges from snowy white to grayish white.

Perlite is a form of natural volcanic glass, and is classified as chemically inert, with a pH of approximately 7.
Expanded perlite can be manufactured to weigh as little as 2 pounds per cubic foot (32 kg/m3) making it adaptable for numerous applications.

Historical Origin. As is often the case, the fact that crushed perlite expands under high heat was discovered by accident.
In 1939, Lee Boyer operated an assay office in Superior, Arizona. He’d been working for months to fuse a mixture of silicates with hopes of developing a new insulating material for the telephone industry. And then came the day he threw a shovelful of crumbled perlite into the open-end firebox of an old converted assay furnace. The popping that followed was a surprise, as was the end result—frothy mineral nuggets with a bubbly cellular structure of sealed pores. Perfect to resist heat conduction! With further help from the Arizona Department of Mineral Resources, he discovered why—perlite contains a small percentage of trapped water in the raw ore. They also worked to quantify the insulative, fire-proof and lightweight character of expanded perlite. A small pilot plant provided Boyer with enough expanded perlite to began exploring applications.

Capacity for Liquid Retention
extreme closeup of expanded perlite particle surface
Expanded perlite is uniquely structured to hold water (and other liquids) with three factors contributing to total capacity: 1) water his held on the frothy surface of a perlite particle, 2) it is held in the voids and channels inherent in physical structure of the individual particles, and 3) it is held between the particles. The last factor—the inter-particle framework holding capacity—is directly related to particle grade and provides great flexibility to industry. Capacity is increased with fine grades, as more densely packed particles provide more surface area and more inter-particle pore spaces to hold water. Larger grades hold less and drain more quickly. The application determines grade selection and moisture retention and release needs.

Effect of Expanded Perlite Aggregate Size on Physical and Mechanical Properties of Ultra Lightweight Concrete Produced with Expanded Perlite Aggregate

ABSTRACT
In this study, ultra-light weight concrete (ULWC) with heat-insulating properties is produced by using different size expanded perlite aggregates and various admixtures.
The compressive strength, 4 point bending strength, freezing and thawing resistance, water absorption, dry unit weight, ultra sound velocities and thermal conductivity of the samples were determined by applying appropriate tests.
The effect of different size expanded perlite aggregate on the properties of ULWC were also investigated in this study and it was found that as the expanded perlite aggregate diameter increased, the void volume uniformity, water absorption percentage and freezing-thawing resistance increased while the unit volume weight of ULWC samples, ultrasound speed velocities, thermal conductivity and compressive strength were decreased.
The changes in the masses and compressive strength of ULWC samples subjected to freezing and thawing cycles were examined.
The compressive strength loss was found to be between 5 % and 47 % while the weight loss was between 1 % and 3.5 % after 15 freezing and thawing cycles.
Finally, the effects of the admixtures on the fresh properties of ULWC were examined and it was determined that the use of 4.5 kg of air-entraining material in one cubic meter of concrete mix is the most ideal ratio and the use of more than 0.01 % by volume of polypropylene fiber is caused settlements in fresh concrete mixtures.

Keywords: expanded perlite, thermal conductivity, mechanical and physical properties, ultra lightweight concrete

March 25, 2022

By admin

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