Silica brick is made of silica with SiO2 content of not less than 96% as raw material, added with mineralizers (such as iron scale, lime milk) and binders (such as sulfite pulp waste liquid), after mixing, molding, drying, firing and other procedures. The higher the SiO2 content in the silica raw material, the higher the refractoriness of the product. Impurity components such as K2O.Na2O are harmful and will seriously reduce the refractoriness of refractory products. Impurities such as Fe2O3, CaO, and MgO act as fluxes. The raw materials of high-grade silica bricks need special treatment to remove impurities.
.jpg)
Features of silica brick:
1. Refractoriness and softening temperature under load
The refractoriness of silica bricks is generally 1690-1730℃, and the softening temperature of silica bricks under load is relatively high, about 1650℃. The softening temperature and refractoriness of silica bricks are close to each other, which is mainly because the main crystal phase of silica bricks is tridymite with spearhead twin crystals to form a network structure and the matrix is a glass phase with high viscosity.
2. Slag resistance
Silica brick is an acid refractory material, which has strong resistance to the erosion of acid and weak acid slag and corrosive gas.
.jpg)
3. High temperature volume stability
During the heating process, in addition to a certain thermal expansion, the silica brick also undergoes crystal transformation and volume expansion. If there is untransformed residual quartz in the brick, it will continue to become tridymite or cristobalite at high temperature, resulting in a larger volume expansion.
4. Thermal shock stability
The thermal shock resistance of silica brick is poor, and the water cooling is only 1 or 2 times at 850 °C. The reason is that in the process of high temperature quenching of silica bricks, crystal transformation will occur, resulting in large volume changes. This is a major weakness of silica bricks.
Silica brick is an acidic refractory material, which has strong resistance to acid slag or acid melt erosion, but poor resistance to alkaline material erosion, and is easily damaged by oxides such as Al2O3, K2O, Na2O, etc. Oxides such as FeO and Fe2O3 have good resistance.
.jpg)
Therefore, silica bricks are mainly used to build the carbonization chamber, combustion chamber and partition walls of coke ovens (about 73% of the refractory materials used in a coke oven are silica bricks), high temperature load-bearing of glass pool kilns and kiln roofs, pool walls and hot blast stoves Parts, carbon roasting furnaces and other thermal kilns. In order to improve the production capacity of modern large-scale coke ovens, it is necessary to thin the coke oven carbonization chamber, combustion chamber and partition walls, thus requiring the use of high-density and high-thermal-conductivity silica bricks. There are many varieties of silica bricks, which are divided into silica bricks for coke ovens, silica bricks for hot blast furnaces, silica bricks for electric furnaces, and silica bricks for glass kilns according to their uses. According to the complexity of the brick type, it is divided into standard bricks, ordinary bricks, special-shaped bricks and special-shaped bricks.
Zhengzhou Shennan Refractory Co.,Ltd are professional in producing high quality silica brick , any demands,please don't hesitate contact with me.
 |
+86-15238007351 |
 |
+86-371-86039318 |
 |
annie@snrefractory.com |
 |
www.snrefractory.com |
