is a fused cast refractory block produced by melting of pure oxides in an electric arc furnace at approx. 1950°C and casting into moulds. During cooling a contraction cavity is formed beneath the casting scar. The surface opposite the casting scar is used as the working face. Within the working zone the block has a very dense structure. The ingress of aggressive media cannot occur because of the low porosity and the specially developed composition. As a consequence, adhesion of slag can be prevented. The blocks have a high mechanical wear resistance and chemical resistance at high temperatures (crystalline bond, high α-corundum content, special composition). The blocks can resist high surface loads because of the high hot compression strength. The relatively high thermal conductivity creates a uniform heat distribution within the billets / slabs.