Can high-alumina bricks replace silica bricks?

High-alumina bricks can replace silica bricks. Attached are the characteristic parameters of high-alumina bricks and silica bricks: High-alumina bricks are neutral refractory materials with an alumina content of over 48%. It is produced by shaping and calcining bauxite or other raw materials with a high alumina content. It has high thermal stability, with a fire resistance temperature of over 1770°C. It has good slag resistance. Used for lining steelmaking electric furnaces, glass melting furnaces, cement rotary kilns, etc. It is mainly used for lining blast furnaces, hot blast stoves, electric furnace roofs, blowout furnaces, reverberatory furnaces, and rotary kilns. In addition, high-alumina bricks are also widely used as regenerative grid bricks in open-hearth furnaces, plug heads for casting systems, and tuyere bricks. However, high-alumina bricks are more expensive than clay bricks; therefore, where clay bricks can meet the requirements, there is no need to use high-alumina bricks. Silicon brick has a silica content of over 93%. True density is 2.38 g/cm3. It has resistance to acidic slag erosion. Higher high-temperature strength. The onset temperature of load softening is 1620–1670°C. Does not deform under long-term use at high temperatures. There is generally no polymorphic transformation above 600°C. Smaller coefficient of thermal expansion. Higher thermal shock resistance. Below 600°C, there are many crystal phase transformations, significant volume changes occur, and thermal shock resistance deteriorates. Using natural silica as the raw material, along with an appropriate amount of mineralizing agent to promote the conversion of quartz in the green body to phosphenite. It is slowly fired at 1350–1430°C in a reducing atmosphere. 　　It is mainly used for partition walls in the carbonization chamber and combustion chamber of coke ovens, as well as for the regenerative chambers and slag chambers of steelmaking flat furnaces, soaking furnaces, glass melting furnaces, and the arches and other load-bearing parts of kilns used for firing refractory materials and ceramics. It is also used in the high-temperature load-bearing parts of hot blast stoves and the roofs of acid converters.

As for whether high-alumina bricks can replace silica bricks, it depends on the process parameters of the application area. Due to the strict requirements for the heating of silica bricks, with a slow rate of heating – especially below 300 degrees – and their poor resistance to sudden changes in temperature, their advantage lies in their ability to withstand high temperatures, though they are not resistant to alkali corrosion. High-alumina bricks contract under high temperatures and in insulated conditions, so special attention is required in areas with large spans. In an alkaline atmosphere, they tend to flake off, especially bricks with high aluminum content. High aluminum content, suitable for high operating temperatures. If the maximum operating temperature reaches 1400 degrees and it is not for long-term use in situations where the fire needs to be stopped or the temperature reduced frequently, it is recommended to use high-alumina bricks instead of silica bricks, as they are certainly superior to silica bricks.