Vermiculite

　　1. Character and structure

　　Its chemical formula is (Mg,Ca)0.7(Mg,Fe,Al)6.0〔(Al,Si)8.0〕(OH48H2O).

　　Vermiculite can be divided into raw vermiculite and swell vermiculite according to its phases. According to its colours we can divide it into golden,silvery and milky-white vermiculite.

　　The volume of raw vermiculite can expand 8-20 times through roasting baking at high temperature.After expanding its specific gravity is 130-180kg/m3.At that same time it has good property of resisting cold or heat.

　　2.The chemical composition

composition	SiO2	Al2O3	MgO	Fe2O3	CaO	PH	H2O
content（%）	37-42	9-17	11-23	5-18	0.5-0.8	8-11	<1

　　3.Main specifications and technical index

　　(1)Raw vermiculite

specifications	No.2	No.3	No.4	No.5
size（mm）	5-7	3-5	1-3	<1

　　(2)Swell vermiculite

level	relax specific gravity	absorbency（%））	impurity（kg/m3）
1	130	480	<1
2	160	450	<1
3	180	420	<1

　　4. Main use

　　Vermiculite is used in construction as lightweight materials or fireproof and anti-heating materials.It can also used in metallurgy farming、foresting、 marine fishing 、gardening and other fields.