Corundum Refractory Castable

Corundum castables are made of fused aluminate cement as a binder, α-Al2O3 and corundum as powder, corundum, mullite and magnesia-aluminum spinel as refractory aggregates, admixtures, mixed in proportion, mixed with water, molded and cured. Corundum castables have the characteristics of rapid hardening and early strength, high purity, high refractoriness, high load softening temperature and high strength. The maximum operating temperature is 1800℃. They are generally used in special parts of thermal equipment.

2. Performance and application of refractory castables

When corundum castables are prepared, refractory powder is fused corundum powder, the maximum particle size of refractory aggregate is 5mm, and its particle size distribution (%) is: 5-1mm. At the same time, composite admixtures such as retarders and water reducers are used. After the initial setting of the castable, it should be cured naturally in a humid environment or by standard curing because a lot of hydration heat is released within 8 hours. However, it is not suitable to be cured in water. After the curing period expires, the strength at room temperature should be tested. The strength change characteristics of the corundum castable are basically the same as those mentioned above, and the strength at medium temperature also decreases, but the absolute value of the strength is relatively high. Its drying compressive strength is 33~41MPa. In order to improve the refractoriness and high temperature performance of cement, an appropriate amount of α-Al2O3 is added to make the Al2O3 content in the cement greater than 77%, and the refractoriness reaches above 1750℃.