Perlite


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perlite

[′pər‚līt]
(geology)
A rhyolitic glass with abundant spherical or convolute cracks that cause it to break into small pearllike masses or pebbles, usually less than a centimeter across; it is commonly gray or green with a pearly luster and has the composition of rhyolite. Also known as pearlite; pearlstone.

Perlite

A lightweight, expanded mineral bead; highly flame resistant and with good insulating value.

Perlite

 

an acid volcanic glass with fine, concentric cracks along which a specimen breaks into small pebbles that sometimes have a pearly luster; such cracks are characteristic of perlitic structure.

The composition of perlite resembles that of acid lavas, for example, liparite and dacite, which are chiefly composed of 65 to 75 percent SiO2 and 10 to 15 percent Al2O3 and which also include admixtures of Fe2O3, CaO, MgO, SO3, and R2O in proportions that range from fractions of a percent to single percentage units. Perlite can also contain as much as 3 to 6 percent constitutional water, that is, water which is bound into hydrated crystals. When crushed perlite is rapidly heated, the enclosed water evaporates, thus swelling the softened rock and increasing the specimen’s volume ten to 20 times. The swelling temperature of perlite, which depends on the water content and chemical composition, ranges from 850°C to 1000°C and sometimes reaches 1200°C. Expanded perlite grains have a low density that ranges from 70 to 600 kg/m3; they are thus suitable for use as sand or rubble in aggregates for lightweight concrete as well as in heat-insulating products, for example, those made from perlite and bitumens, perlite and silicates, and perlite and ceramics. Expanded perlite is also used in the chemical, petroleum-refining, food, and pharmaceutical industries and in glassmaking and agriculture.

Perlite is widely used in many countries throughout the world. The USSR has aggregate geological reserves of perlite that are estimated at approximately 500 million m3. More than 600,000 m3 of perlite was extracted in 1974, including 427,000 m3 from the Aragats deposit in the Armenian SSR, 110,000 m3 from the Beregovo deposit in the Ukrainian SSR, and 66,000 m3 from the Mukhor-Tala deposit in the Buriat ASSR.

V. M. BORZUNOV

perlite

A siliceous volcanic rock; under heat it expands to 15 to 20 times its original volume, forming an excellent lightweight aggregate; used in plaster or gypsum wallboard, as loose-fill thermal insulation, and as an aggregate in concrete.
References in periodicals archive ?
Global Perlite Mining Market Report 2019 from the publisher provides the strategists, marketers and senior management with the critical information they need to assess the global perlite mining market.
Company is progressing a low capital cost concept to produce a horticultural grade raw perlite and by-product finely crushed natural pozzolan using mobile processing equipment.
Sunrise said a seven-ton bulk sample of perlite was processed to produce a horticultural grade raw perlite and a finely crushed perlite for sale as natural pozzolan.
For the ritual opening of the garden season, I give my garage floor a clean sweep and then make a pile of 2 gallons each of garden soil, peat moss, perlite and compost.
The chemical composition of cement, nanosilica, perlite, and expanded clay was determined by X-ray fluorescence (XRF) using ARL 8680 S equipment in boron lithium oxide ([B.sub.4][Li.sub.2][O.sub.7]) pills.
(i) Perlite is a mineral insulation, produced from volcanic rocks, with a density close to 1100 kg/[m.sup.3].
As a second time exhibitor, Emir Ergec, Techincal engineer, explains that the properties of the concrete make it unique: "Foam concrete is used extensively in construction, however, perlite is 100% volcanic rock and is nothing like a polymer-based product."
You'll need an empty Altoids tin, some perlite, a piece of window screen, and denatured alcohol.
Among the topics are assessing glassy phase reactivity in fly ashes used for geopolymer cements, the suitability of volcanic amorphous aluminosilicate rocks (perlite) for synthesizing geopolymer-based concrete, a statistical-based approach for predicting the mechanical properties of geopolymer concretes, performance-based specification for geopolymer cement binders and supporting laboratory data, and the path to standardization.
Saudi Perlite lndustries, a pioneer in the field of thermal and cryogenic insulation, manufactures expanded perlite at one of the biggest facilities of its kind in the region.
The best way to do a cutting is to snip off about 4 inches and strip off the lower leaves and then stick the stem into a soilless potting mix, like perlite or vermiculite.
The company's efforts to produce high-quality glass on the basis of the local perlite failed.