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Information about Perlite

For the two-phased structure in steel see pearlite.


Enlarge picture
Expanded 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.

Properties and uses

When it reaches temperatures of 850–900 °C, perlite softens (since it is a glass). Water trapped in the structure of the material vapourises 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 bulk density: around 1100 kg/m³ (1.1 g/cm³).
Typical expanded perlite bulk density: 30–150 kg/m³

Due to its low density and relatively low price, many commercial applications for perlite have developed. In the construction and manufacturing fields, it is used in lightweight plasters and mortars, insulation, ceiling tiles and filter aids. In horticulture it makes composts more open to air, while still having good water-retention properties; it makes a good medium for hydroponics. Perlite is also used in foundries, cryogenic insulations, as a lightweight aggregate in mortar (firestop) and in ceramics as a clay additive.

Typical analysis of perlite

Production trends

Enlarge picture
Perlite output in 2005
In 2005, Greece was the top producer of perlite with at least one-third world share followed by China, USA, Japan and Turkey, reports the British Geological Survey.

In 2001 the cost of perlite was about US$36.31 per metric ton. The yearend price for mined perlite in the US has increased since then[1]:
2001.....$36.3 per metric ton
2002.....$36.5 per metric ton
2003.....$38.2 per metric ton
2004.....$40.6 per metric ton
2005.....$42.5 per metric ton

See also

References

1. ^ (January 2006) "Perlite". U.S. Geological Survey Mineral Commodity Summaries,: 122-123. [1]. 

External links

Pearlite is a two-phased, lamellar (or layered) structure composed of alternating layers of alpha-ferrite (88 wt%) and cementite (12%) that occurs in some steels and cast irons. It forms by a eutectoid reaction as austenite is slowly cooled below 727°C.
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An amorphous solid is a solid in which there is no long-range order of the positions of the atoms. (Solids in which there is long-range atomic order are called crystalline solids or morphous). Most classes of solid materials can be found or prepared in an amorphous form.
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Volcano:
1. Large magma chamber
2. Bedrock
3. Conduit (pipe)
4. Base
5. Sill
6. Branch pipe
7. Layers of ash emitted by the volcano
8. Flank 9. Layers of lava emitted by the volcano
10. Throat
11. Parasitic cone
12. Lava flow
13. Vent
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Glass is a noncrystalline material that can maintain indefinitely, if left undisturbed, its overall form and amorphous microstructure at a temperature below its glass transition temperature.
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Water is a common chemical substance that is essential to all known forms of life.[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor.
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Obsidian is a type of naturally-occurring glass formed as an extrusive igneous rock. It is produced when felsic lava erupted from a volcano cools rapidly through the glass transition temperature and freezes without sufficient time for crystal growth.
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Bulk density a property of particulate materials. It is the mass of many particles of the material divided by the volume they occupy. The volume includes the space between particles as well as the space inside the pores of individual particles.
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construction is the building or assembly of any infrastructure on a site or sites. Although this may not be thought of as a single activity, in fact construction is a feat of multitasking.
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plaster used in spray fireproofing in a low-rise industrial building in Vancouver, British Columbia.]]

Plaster of Paris, or simply plaster, is a type of building material based on calcium sulfate hemihydrate, nominally CaSO4·0.5H2O.
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Mortar is a material used in masonry to fill the gaps between blocks in construction. The blocks may be stone, brick, breeze blocks (cinder blocks), etc. Mortar is a mixture of sand, a binder such as cement or lime, and water and is applied as a paste which then sets hard.
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thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer.

Heat is transferred from one material to another by conduction, convection and/or radiation.
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Horticulture (Latin: hortus (garden) + cultura (culture)) is the culture or growing of garden plants. Horticulture as classically defined is the subdivision of agriculture dealing in gardening, in contrast to agronomy, which deals with field crops and the
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Hydroponics is a method of growing plants using mineral nutrient solutions instead of soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel or Rockwool. A variety of techniques exist.
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foundry is a factory which produces metal castings from either ferrous or non-ferrous alloys. Metals are turned into parts by melting the metal into a liquid, pouring the metal in a mold, and then removing the mold material or casting.
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cryogenics is the study of the production of very low temperatures (below –150 °C, –238 °F or 123 K) and the behavior of materials at those temperatures. (Rather than the familiar temperature scales of Fahrenheit and Celsius, cryogenicists use the Kelvin and Rankine
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Firestop mortars are most typically used to firestop large openings in walls and floors required to have a fire-resistance rating. They are passive fire protection items subject to stringent bounding. Firestop mortars most often exhibit densities near 1kg/L.
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Ceramics and ceramic art in the art world means artwork made out of clay bodies and fired into the hardened ceramic form. Some ceramic pieces are classified as fine art, while many others can be classified as one of the decorative, industrial or applied arts (the application
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Clay is a naturally occurring material, composed primarily of fine-grained minerals, which show plasticity through a variable range of water content, and which can be hardened when dried or fired.
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silicon dioxide, also known as silica or silox (from the Latin "silex"), is the oxide of silicon, chemical formula SiO2, and has been known for its hardness since the 16th century.
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Aluminium oxide is an amphoteric oxide of aluminium with the chemical formula Al2O3. It is also commonly referred to as alumina in the mining, ceramic and materials science communities.
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Sodium oxide is a chemical compound with the formula Na2O. It is used in ceramics and glasses. Treatment with water affords sodium hydroxide.
Na2O + H2O → 2 NaOH


The alkali metal oxides M2
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Potassium oxide is a compound of potassium and oxygen used mainly as an intermediate in inorganic synthesis. It is formed by reacting metallic potassium with a limited supply of oxygen.
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Ferruginous redirects here. For the bird, see Ferruginous Hawk


Altogether there are sixteen known iron oxides.[1] These compounds are either oxides (Wüstite, Hematite, β-Fe2O3, Maghemite, γ-Fe2O
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Magnesium oxide, or magnesia, is a white solid mineral that occurs naturally as periclase and is a source of magnesium. See also oxide. It has an empirical formula of MgO. It is formed by an ionic bond between one magnesium and one oxygen atom.
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Calcium oxide (CaO), commonly known as burnt lime, lime or quicklime, is a widely used chemical compound. It is a white, caustic and alkaline crystalline solid.
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British Geological Survey

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Headquarters Keyworth, Nottinghamshire

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tonne (t) or metric ton (M/T), also referred to as a metric tonne, is a measurement of mass equal to 1,000 kilograms. It is not an SI unit but is accepted for use with the SI.
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