Lightweight Silica Refractory Brick for Glass Melting Furnaces in Industrial Settings

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.

Using finely divided silica as raw material, the critical particle size is usually no more than 1mm, and the particles smaller than 0.5mm are no 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℃.

Silica heat-insulating refractory bricks generally use crystalline quartzite or silica sand as raw materials, and the mineral composition is: phosphorite 78% to 86%, cristobalite 13% to 15%, and quartz 4% to 7%. Add combustible materials to the ingredients, such as coke, sawdust, anthracite, carbonized rice husk, or use gas foaming to form a porous structure. Silicone heat-insulating refractory bricks are heat-insulating silicon refractory products with a SiO2 content of more than 90% and a bulk density of less than 1.2.

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. It is similar to the production process of ordinary silica bricks. Some mineralizers (CaO, Fe2O3) are added to the ingredients to promote the conversion of quartz, and pulp waste liquid is used as a binder to make the bricks have a certain strength. When using coke or anthracite as combustible additives, because the ash will be brought into Fe2O3 and Al2O3, there is no need to add iron scales in the ingredients. When the siliceous heat-insulating refractory bricks are fired, a strong oxidizing flame should be maintained before 1200°C to make the additions burn out completely.

Silicone heat-insulating refractory bricks have the characteristics of low thermal conductivity, high load softening temperature, small residual expansion, and excellent reburning line change performance. They are suitable for industrial furnaces such as coke ovens, hot blast furnaces, glass furnaces and carbon furnaces. It is mainly used for the heat insulation layer and working layer of thermal equipment, and can be used for the heat insulation layer of various high temperature kiln equipment under high temperature conditions (≤1500℃) without contact with molten slag. This product is suitable for the heat insulation material of the silica brick lining of the high temperature hot blast stove of the large blast furnace and the heat insulation of the silica brick masonry of the glass furnace.

General light silica bricks can be divided into two levels: the first grade can be used in the top of the steel rolling heating furnace and the roof of the silicate industrial kiln, 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. Generally, the bulk density of silicon heat insulation refractory bricks is 0.9-1.1g/cm3, the compressive strength is 2.0-5.9MPa, and the thermal conductivity is 0.35-0.42W/(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. 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.