High-alumina refractory brick is an aluminum silicate refractory material with an alumina content of more than 48%. It is formed and calcined from bauxite or other raw materials with high alumina content. It has high thermal stability, refractoriness above 1770℃. And its slag resistance is good. High alumina bricks are the most widely used refractory bricks.
a. Refractoriness
The refractoriness of high alumina bricks is higher than that of clay bricks and semi-silica bricks, reaching 1750~1790℃. They are high-grade refractory materials. The higher the refractoriness, the better the performance, and the its price will increase accordingly.
b. Refractoriness under load
Because high-alumina products have high Al2O3 content, less impurities, and less fusible glass,its refractoriness under load is higher than that of clay bricks. However, because mullite crystals of high-alumina products do not form a network structure, its refractoriness under load is still not as high as that of silica bricks.
c. Slag resistance
High alumina bricks contain more Al2O3, which is close to neutral refractory materials, and can resist the erosion of acid slag and alkaline slag. Because it contains SiO2, the ability to resist alkaline slag is weaker than that of acid slag.
High alumina bricks are mainly used for building lining of blast furnaces, hot blast stoves, electric furnace roofs, blast furnaces, reverberatory furnaces, and rotary kilns. In addition, high alumina bricks are also widely used as open hearth regenerative checker bricks, plugs for pouring systems, nozzle bricks, etc. However, the price of high alumina bricks is higher than that of clay bricks, so it is not necessary to use high alumina bricks where clay bricks can meet the requirements.
