Refractory for casting and process for producing same

A process for producing a highly durable refractory for casting comprising the steps of admixing, based on the total weight of said refractory in each case, 5 -80% by weight of refractory component including the principal mineral phase consisting of mullite, baddeleyite and corundum and having the chemical composition consisting of 25-85% by weight of Al.sub.2 O.sub.3, 10-70% by weight of ZrO.sub.2 and 5-25% by weight of SiO.sub.2, respectively, based on the total weight of said chemical composition and 10 -40% by weight of carbon powder by the use of a binder, moulding said mixture and burning the resulting moulded product in non-oxidation environment.

A process for producing a highly durable refractory for casting comprising the steps of admixing, based on the total weight of said refractory in each case, 5-80% by weight of refractory component including the principal mineral phase consisting of mullite, baddeleyite and corundum and having the chemical composition consisting of 25-85% by weight of Al.sub.2 O.sub.3, 10-70% by weight of ZrO.sub.2 and 5-25% by weight of SiO.sub.2, respectively, based on the total weight of said chemical composition, 10-40% by weight of carbon powder, up to 20% by weight of one or more members selected from the group consisting of SiC, Si.sub.3 N.sub.4, metallic silicon and ferrosilicon, up to 30% by weight of fused silica and up to 60% by weight of alumina powder containing at least 70% by weight of Al.sub.2 O.sub.3 based on the total weight of said alumina powder by the use of a binder, moulding said mixture and burning the resulting moulded product in non-oxidation environment.

A highly durable refractory nozzle for casting comprising, based on the total weight of said refractory in each case, 5-80% by weight of refractory component including the principal mineral phase consisting of mullite, baddeleyite and corundum and having the chemical composition consisting of 25-85% by weight of Al.sub.2 O.sub.3, 10-70% by weight of ZrO.sub.2 and 5-25% by weight of SiO.sub.2, respectively, based on the total weight of said chemical composition and 10-40% by weight of carbon powder.

A process for producing a highly durable refractory nozzle for casting comprising the steps of admixing, based on the total weight of said refractory in each case, 5-80% by weight of refractory component including the principal mineral phase consisting of mullite, baddeleyite and corundum and having the chemical composition consisting of 25-85% by weight of Al.sub.2 O.sub.3, 10 -70% by weight of ZrO.sub.2 and 5-25% by weight of SiO.sub.2, respectively, based on the total weight of said chemical composition, 10-40% by weight of carbon powder, up to 20% by weight of one or more members selected from the group consisting of SiC, Si.sub.3 N.sub.4, metallic silicon and ferrosilicon, up to 30% by weight of fused silica and up to 60% by weight of alumina powder containing at least 70% by weight of Al.sub.2 O.sub.3 based on the total weight of said alumina powder by the use of a binder, moulding said mixture and burning the resulting moulded product in non-oxidation environment.