High-alumina refractory castables for use in the steel industry.

Fourty-eight commercially available refractory castables with an andalusite, bauxite, corundum and spinel base were analysed in terms of their high-temperature properties, such as hot crushing strength and creep resistance for comparison with the theoretical melting behaviour. The matrix composition of the castables deviates from the total composition, because the aluminous cement binder and superfine additives are present solely in the fine-grain range of the castable mix. If the matrix composition of the castables is taken into account in addition to the total composition, it is possible to establish a good correspondence between theoretical and practical behaviour. Comparison of the different groups of raw materials reveals characteristic properties and differences that provide pointers for the use of such refractory castables in the steel industry. The findings can serve the user as a basis for assessment.