Refractory brick made of sillimanite minerals.Sillimanite into after high temperature calcination mullite and free silica.Commonly used high

temperature burning method and mud casting method.The physical and chemical performance is better than high alumina brick, 1770 ~ 1830 ℃,

refractoriness under load softening the starting point of 1500 ~ 1650 ℃.It is mainly used for glass tank furnace discharge hole forming,

blast furnace lining, furnace throat and ceramic industry kiln furniture.

Crystalline silicon steel gray, amorphous silicon is black, 2.4 g/cm3 density, melting point 1414 ℃, boiling point 2355 ℃, crystalline silicon atomic

crystal, hard and glossy, semiconductor properties.Silicon structure are similar to diamond, is a regular tetrahedron structure.Silicon chemistry

more lively, can at high temperature and oxygen etc. Various elements combined, insoluble in water, hydrochloric acid and nitric acid, soluble in

hydrofluoric acid and alkali, used to build alloy such as ferrosilicon, silicon steel, silicon single crystal is a kind of important semiconductor materials,

used in the manufacture of high power transistor, rectifier, solar cells, etc.Silicon is widespread in nature, containing about 27.6% of the earth's crust,

mainly exists in the form of silica and silicates.In the crust, the content of silicon in all elements content is second only to oxygen, second.Its shape is divided into crystalline form and network form