ALUMINA-MAGNESIA CASTABLES FOR LADLE

摘要

Alumina-magnesia based amorphous refractory composition for ladle is provided to give excellent corrosion resistance and permeation resistance to the ladle used in steel work when used for fabricating ladle wall body or floor of a molten steel container by comprising alumina and magnesium clinker, baked alumina and silica flower, as well as sodium hexametaphosphate as dispersant. The refractory composition comprises: 73 to 85wt.% of alumina clinker having particle size of 0.044 to 5mm; 6 to 10wt.% of magnesia clinker having particle size of 0.3 to 0.7mm; 3 to 5wt.% of calcined alumina powder having particle size of 3 to 6 micrometers; 5 to 10wt.% of calcined alumina having 0.3 to 0.6 micrometers which is called "ultrafine calcined alumina"; and 1.0 to 2.0wt.% of silica flower having particle size of 0.1 to 0.2 micrometers. The composition further includes external additive in amount of 0.1 to 0.2wt.% based on 100wt.% of the composition. The additive is sodium hexametaphosphate as dispersant.