ALUMINA-SPINEL PREPARED UNSHAPED REFRACTORY FOR TROUGH OF BLAST FURNACE

摘要

PROBLEM TO BE SOLVED: To ensure superior oxidation resistance by incorporating graphite subjected to hydrophilic treatment, fine alumina and magnesia powders each having a specified average particle diameter and alumina and/or spinel as aggregate. SOLUTION: Graphite powder subjected to hydrophilic treatment is prepd. by coating the surface of graphite with fine alumina or silica powder or crushing flake graphite into spheres having 10-200μm average particle diameter and an aspect ratio of 0.8-1.2. The prepd. graphite powder, fine alumina powder having about 0.3-75μm average particle diameter and fine magnesia powder having about 2-75μm average particle diameter provided with slaking resistance by surface coating with a hydrophilic inorg. material such as a silica sol are added to alumina and/or spinel as aggregate as a principal component by 3-20wt.%, 6-30wt.% and 2-20wt.%, respectively, are prescribed amts. of a dispersant such as sodium tripolyphosphate and a hardening agent such as alumina cement are further added if necessary. They are blended to obtain the objective prepared unshaped refractories.