DRYING METHOD FOR ALUMINA-MAGNESIA AMORPHOUS REFRACTORY MATERIAL AND AMORPHOUS REFRACTORY MATERIAL PRODUCED BY THAT METHOD

摘要

PROBLEM TO BE SOLVED: To prevent generation of cracks on a heated surface when an alumina- magnesia amorphous refractory material is dried by heating, by keeping the surface of the refractory material at specified temp. for specified time to form a spinel structure on the surface layer. ;SOLUTION: After an alumina-magnesia amorphous refractory material is applied and dried, the surface temp. is maintained at ≥1300°C for ≥4 hours. A spinel structure is produced at ≥1000°C surface temp., however, at 1000 to 1300°C, the growing rate of the spinel structure is slow and long time is required to grow. The reason why the surface temp. is kept for ≥4 hours is to heat the refractory material at ≥1000°C to the inside of the material as ≥60mm deep from the surface so that the spinel structure grows to that depth. By this method, when the amorphous refractory material is drastically heated or cooled by contact with a molten metal, difference in expansion in a high temp. range is not generated because the spinel structure is produced to ≥60mm inside of the surface. Thus, cracks generating parallel to the heated surface of the amorphous refractory material can be prevented.;COPYRIGHT: (C)1998,JPO