Introduction to Lightweight Silica Brick

Lightweight silica bricks are also called silica insulation bricks. Lightweight refractory material with silicon dioxide above 91% and bulk density below 1.2g/cm3. The refractoriness and softening temperature under load are not much different from ordinary silica bricks with the same composition. However, due to the many pores, the compressive strength, slag resistance, and corrosion resistance are not as good as ordinary silica bricks, but the thermal shock resistance has been improved.

Raw material of light silica brick

Lightweight silica bricks use finely divided silica as raw materials, and their critical particle size is usually not more than 1mm, and the particles smaller than 0.5mm are not less than 90%. It is prepared by adding flammable substances to the ingredients or adopting the gas generation method to form a porous structure and firing. Can also be made into unburnt products. It is mainly used for all parts of the kiln that requires heat insulation or lightening of its own weight without direct contact with the melt, free from corrosive gas, and not subject to sudden temperature changes. It is used at high temperature and cannot be in contact with alkaline refractory materials. According to different materials, the highest operating temperature is 1200～1550℃.

The mineral composition of light silica bricks

Phosphorite is 78% to 86%, cristobalite is 13% to 15%, and quartz is 4% to 7%. The bulk density is 0.9 to 1.19 g/cm3, the compressive strength is 2.0 to 5.9 MPa, and the thermal conductivity is 0.35 to 0.42 W?(m?K). It has excellent fire resistance. Its softening temperature under load is close to 1620℃ for dense silica bricks, with only a small residual expansion, and its thermal stability is better than dense silica bricks.

Features and application of light silica brick

Lightweight silica bricks generally use crystalline quartzite or silica sand as raw materials, and add flammable materials such as coke, anthracite, sawdust, carbonized rice husk or gas foaming to form a porous structure. The refractoriness and softening temperature under load are not much different from ordinary silica bricks with the same composition. However, due to many pores, the compressive strength, slag resistance, and corrosion resistance are not as good as ordinary silica bricks.

Generally light silica bricks can be divided into two levels: the first grade can be used in the top of the steel rolling furnace and the silicate industrial kiln roof, and can be directly in contact with the flame; the second grade is used in the general industrial kiln Insulation. Applicable to: industrial furnaces such as coke ovens, hot blast furnaces, glass melting furnaces and carbon calciners. It has excellent fire resistance. Its softening temperature under load is close to 1620℃ for dense silica bricks, with only a small residual expansion, and its thermal stability is better than dense silica bricks. Therefore, siliceous heat insulating refractory bricks can be used for a long time under high temperature conditions (1500-1550°C) without contact with molten slag, but they are especially suitable for high temperature hot blast furnaces of large blast furnaces. Thermal insulation of silica brick gas.