Vermiculite has kinds of uses taking advantage of its low density, good insulating properties,inertness,fire resistance etc.

 

Vermiculite is a hydrated magnesium-aluminum-iron silicate Flakes of raw vermiculite concentrate are mica-like in appearance and contain water molecules within their internal structure. When the flakes are heated rapidly at a temperature of 900 degree celsius or higher, the water flashes into steam, and the flakes expand into accordion-like particles. The color, which can range from black and various shades of brown to yellow for the raw flakes, changes to gold or bronze. This expansion process is called exfoliation, and the resulting lightweight material is chemically inert, fire resistant, and odorless. In lightweight plaster and concrete, vermiculite provides good thermal insulation. Vermiculite can absorb such liquids as fertilizers, herbicides, and insecticides, which can then be transported as free-flowing solids.

Consumption

Vermiculite has a wide range of uses that take advantage of its attributes, such as low density, good insulating properties,inertness, fire resistance, and high liquid absorption capacity.

Vermiculite is used in general building plasters either in its own formulations or combined with such other aggregates as perlite. Specialist plasters include fire protection and acoustic products in which vermiculite is combined with a binder, such as gypsum or portland cement, plus fillers and rheological aids Exfoliated vermiculite treated with a water repellent is used to fill pores and cavities in masonry construction (especially hollow blockwork) to enhance fire ratings, insulation, and acoustic performance. Exfoliated finer grades of vermiculite are used to produce insulation shapes. The manufacturing process is very similar to that used for the production of silicate-bound building boards.

Vermiculite-based insulation shapes can be used in lower temperature metal-melting-processing industries; vermiculite can be used in contact with molten metal up to 1,200 degree Celsius .Vermiculite shapes are used in the aluminum industry, in particular, because vermiculite is said to have a nonwetting characteristic with aluminum. Exfoliated vermiculite has been combined for many years with high alumina (also known as aluminous or calcium aluminate) cements and such aggregates as expanded shale, clay, and slate to produce refractory and/or insulation concretes and mortars. These are used in areas where strength and corrosion/abrasion resistance are of secondary importance; the most important factor is the insulation performance of the inplace refractory lining. These mixes are used in such industries as iron and steel, cement, and hydrocarbon processing

In horticulture, exfoliated vermiculite improves soil aeration and moisture retention. When vermiculite is mixed with peat or other composted materials, such as pine bark, the resulting product provides a good growing medium for plant propagation. As a soil conditioner, exfoliated vermiculite can improve the aeration of sticky soils and the water holding characteristics of sandy soils. This allows for easier watering and reduces the likelihood of cracking, crusting, and compaction of the soil.

Vermiculite is used in the fertilizer/pesticide market because of its ability as a carrier, bulking agent, and extender Finer grades of exfoliated vermiculite are used to partially replace asbestos in brake linings primarily for the automotive market

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China Vermiculite.

Although data were not fully available, output of vermiculite was estimated to be at least 30,000 to 40,000 t/y (2003) from the four main producers in Xinjiang Province. An additional 15,000 t of output was estimated to have been produced in Hebei Province. Hebei Vermiculite classifies into two types. Silver-white vermiculite contains 5% to 13% iron oxide (Fe2O3) and is for use in the construction industry. Golden yellow vermiculite, with 16% to 22% Fe2O3, is used in agriculture and horticulture. Export destinations for Chinese vermiculite included Japan, the Republic of Korea, and North America