Vermiculite is a natural, inorganic, non-toxic mineral that expands under high temperature.

After high temperature baking, the volume of vermiculite can rapidly expand several times to dozens of times, the volume of vermiculite after expansion is called expanded vermiculite, which is a layered structure, the layer contains crystal water, the bulk weight is 50-200kg/m3, the thermal conductivity is small, is a good thermal insulation material. Good quality expanded vermiculite, the maximum use temperature can reach 1100℃.

In addition, expanded vermiculite has good electrical insulation. Expanded vermiculite is widely used in insulation materials, fireproof materials, seedlings, flowers, trees, friction materials, sealing materials, electrical insulation materials, coatings, plates, paints, rubber, refractory materials, hard water softener, smelting, construction, shipbuilding, chemical and other industries.

In agriculture, vermiculite can be used as a soil amendment, because of its good cation exchange and adsorption, can improve the structure of the soil, water storage and retention, improve the soil permeability and water content, acid soil into neutral soil; Vermiculite can also play a buffer role, hinder the rapid change of PH value, so that fertilizer is slowly released in the crop growth medium, and allow slightly excessive use of fertilizer without harm to the plant; Vermiculite can also provide crops with K, Mg, Ca, Fe and trace amounts of Mn, Cu, Zn and other elements. The properties of water absorption, cation exchange and chemical composition of vermiculite make it play multiple roles such as fertilizer preservation, water retention, water storage, air permeability and mineral fertilizer. The experiment showed that 0.5-1% of expanded vermiculite was added into the compound fertilizer, which could increase the crop yield by 15-20%.