Perlite is an amorphous An "amorphous solid" is a solid in which there is no long-range order of the positions of the atoms. . Most classes of solid materials can be found or prepared in an amorphous form. For instance, common window glass is an amorphous solid, many polymers (such as polystyrene) are amorphous, and even junkfoods such as cotton candy are volcanic A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot magma, ash and gases to escape from below the surface glass Glass is an amorphous solid material. Glasses are typically brittle, and often optically transparent. Glass is commonly used for windows, bottles, and eyewear; examples of glassy materials include soda-lime glass, borosilicate glass, acrylic glass, sugar glass, Muscovy-glass, and aluminium oxynitride. The term glass developed in the late Roman that has a relatively high water Water is a chemical substance with the chemical formula H2O. Its molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state, water vapor or steam content, typically formed by the hydration of obsidian Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly without crystal growth. Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows, where the chemical composition induces a high viscosity and polymerization. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. It is an industrial mineral Industrial minerals are geological materials which are mined for their commercial value, which are not fuel and are not sources of metals (metallic minerals). They are used in their natural state or after beneficiation either as raw materials or as additives in a wide range of applications and a commercial product useful for its light weight after processing.

Contents

Properties

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 has a bulk density Bulk density is a property of powders, granules and other "divided" solids, especially used in reference to soil. It is defined as the mass of many particles of the material divided by the total volume they occupy. The total volume includes particle volume, inter-particle void volume and internal pore volume around 1100 kg/m³ (1.1 g/cm³), while typical expanded perlite has a bulk density of about 30–150 kg/m³.

Uses

Due to its low density and relatively low price, many commercial applications for perlite have developed. In the construction In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of multitasking. Normally the job is managed by the project manager and supervised by the construction manager, design engineer, and manufacturing fields, it is used in lightweight plasters The term plaster can refer to gypsum plaster , lime plaster, or cement plaster and mortars Mortar is a workable paste used to bind construction blocks together and fill the gaps between them. The blocks may be stone, brick, cinder blocks, etc. Mortar becomes hard when it sets, resulting in a rigid aggregate structure. Modern mortars are typically made from a mixture of sand, a binder such as cement or lime, and water. Mortar can also be, insulation The term 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 energy can be transferred by conduction, convection, radiation or by actual movement of material from one location to another. For the purposes of this discussion only the first three, ceiling tiles, in horticulture and as filter aid.

In horticulture Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic engineering, plant biochemistry, and plant physiology, perlite can be used as a soil amendment or alone as a medium for hydroponics Hydroponics is a method of growing plants using mineral nutrient solutions, in water, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel, mineral wool, or coconut husk or for starting cuttings Plant cutting, also known as striking/cloning, is a technique for vegetatively propagating plants in which a piece of the source plant containing at least one stem cell is placed in a suitable medium such as moist soil, potting mix, coir or rock wool. The cutting produces new roots, stems, or both, and thus becomes a new plant independent of the. When used as an amendment it helps prevent water loss and soil compaction.

Perlite is an excellent filter aid Filtration is a mechanical or physical operation which is used for the separation of solids from fluids by interposing a medium through which only the fluid can pass. Oversize solids in the fluid are retained, but the separation is not complete; solids will be contaminated with some fluid and filtrate will contain fine particles (depending on the. It is used extensively as an alternative to diatomaceous earth Diatomaceous earth also known as diatomite or kieselgur, is a naturally occurring, soft, siliceous sedimentary rock that is easily crumbled into a fine white to off-white powder. It has a particle size ranging from less than 1 micron to more than 1 millimeter, but typically 10 to 200 microns. This powder has an abrasive feel, similar to pumice. The popularity of perlite usage in this application is growing considerably worldwide.

Small quantities of perlite are also used in foundries A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal in a mold, and removing the mold material or casting after the metal has solidified as it cools. The most common metals processed are aluminum and cast iron. However, other metals, such as steel, magnesium, copper, tin,, cryogenic In physics, cryogenics is the study of the production of very low temperature and the behavior of materials at those temperatures. A person who studies elements under extremely cold temperature is called a cryogenicist. Rather than the familiar temperature scales of Celsius and Fahrenheit, cryogenicists use the Kelvin scale (formerly also Rankine insulation, as a lightweight aggregate in mortar (firestop) 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. Firestop mortars most often exhibit densities near 1 kg/L. This makes the product easy enough to handle, yet heavy enough to absorb a lot of heat from penetrants, to keep the and in ceramics In art history, ceramics and ceramic art mean art objects such as figures, tiles, and tableware made from clay and other raw materials by the process of pottery. Some ceramic products are regarded as fine art, while others are regarded as decorative, industrial or applied art objects, or as artifacts in archaeology. They may be made by one as a clay additive. It is also used by the explosive industry.[1]

In 2007, estimated U.S. usage applications are shown in the following table:

portion general usage[2]
60% building construction products
14% horticultural aggregate
11% fillers
7.5% filter aid
7.5% other

Typical analysis of perlite

Production trends

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.[3]

The cost of perlite has varied since 2001.[4]:

end of year Price in the US $ per t The tonne or metric ton (U.S.), also referred to as a metric tonne, is a unit of mass equal to 1,000 kg (2,204.62262 lb) or approximately the mass of one cubic metre of water at four degrees Celsius. It is sometimes abbreviated as mt in the United States, but this conflicts with other SI symbols. The tonne is not a unit in the International System
2001 36.3
2002 36.5
2003 38.2
2004 41.8[2]
2005 40.5[2]
2006 42.9
2007 51.6
2008 60.0

See also

References

  1. ^ Emulsion explosive composition containing expanded perlite United States Patent 4940497
  2. ^ a b c http://minerals.usgs.gov/minerals/pubs/commodity/perlite/mcs-2008-perli.pdf
  3. ^ Reported by the British Geological Survey The British Geological Survey is a partly publicly-funded body which aims to advance geoscientific knowledge of the United Kingdom landmass and its continental shelf by means of systematic surveying, monitoring and research. The BGS headquarters are in Keyworth, Nottinghamshire, but other centres are located in Edinburgh, Wallingford, Cardiff and
  4. ^ "Perlite". U.S. Geological Survey Mineral Commodity Summaries,: 122–123. January 2006. [1].

External links

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Categories: Felsic rocks | Vitreous rocks | Granular materials A granular material is a conglomeration of discrete solid, macroscopic particles characterized by a loss of energy whenever the particles interact . The constituents that compose granular material must be large enough such that they are not subject to thermal motion fluctuations. Thus, the lower size limit for grains in granular material is about 1

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'Perlite' Answers
when adding perlite or vermiculite to soil...?
Q. i am adding perlite and vermiculite to my garden soil. i am just curious if this stuff would disaolve or lose its effectiveness if i added it at the end of the growing season when you till up all your plants. i want everything ready to go for next year, but not if my perlite and such are going to lose their properties by being in the ground for so long. any thoughts?
Asked by Ricardus - Sat Nov 15 15:48:16 2008 - - 2 Answers - 0 Comments

A. I prefer adding soil amendments that have an organic content, like leaves, straw, compost, newspapers, lawn clippings, etc.. Perlite seems like an expensive soil additive. I didn't know you could still buy vermiculite, I thought it was mostly banned now because it has asbestos in it??? Well, maybe it's available where you live. Both perlite and vermiculite are/were used in potting soil, where the soil goes through regular cycles of being watered and then drying out. I suspect, though, that when they're in your garden, they're going to fill up with water, and then stay that way. Organic material does the same thing, costs less, and provides nutrition, too. For those reasons, I wouldn't use either perlite or vermiculite in my garden… [cont.]
Answered by Don - Sat Nov 15 16:02:35 2008

Yahoo Answers Search: Perlite,
Sat Aug 22 09:57:22 2009
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