Lightweight silicon insulation brick is a kind of heat insulation refractory with the content of SiO2 not less than 91%, which is mainly made of silica.Lightweight silica insulating brick volume density of 0.9 ~ 1.1 g/cm3, thermal conductivity is only half of ordinary silica brick, good thermal shock resistance, the rul start temperature can reach 1600 ℃, far above the clayey insulating brick.Thus the siliceous insulating brick highest use temperature is 1550 ℃.It doesn't contract at high temperatures and even dips slightly. 

Refractory fire light weight silica insulation bricks  are usually made from crystalline quartzite and contain inflammable materials, such as coke and anthracite sawdust, or form porous structures by gas foaming.Similar to the production industry of ordinary silica bricks, some mineralized agents (CaO, Fe2O3) were added into the ingredients to promote the transformation of quartz, and the strength of the bricks was obtained by using the waste pulp as the binder.When coke or anthracite is used as fuel, because ash is carried into Fe2O3 and Al2O3, no additional iron phosphorus is added to the mix.Lightweight silica brick firing, should maintain strong oxidizing flame before 1200 ℃, make join completely burn out. 

 The mineral composition of light silica brick is: phosphoquartz 78 ~ 86%, quartz 78 ~ 86%, quartz 78 ~ 86%.The compressive strength of general lightweight silica bricks is 2.0 ~ 9.5mpa, and the thermal conductivity is 0.35 ~ 0.42w /(m·K).Lightweight silica brick has good fireproof performance, refractoriness under load is close to dense silica brick reached 1620 ℃ above, only a small amount of residual expansion, and its thermal stability is better than dense silica brick.Therefore, lightweight silica brick can be in contact with slag of high temperature 1500 ~ 1550 ℃ under the condition of use for a long time.Table 1 lists the technical conditions of light silicon bricks used in industrial kilns in China.