| 摘要 |
PROBLEM TO BE SOLVED: To obtain a refractory having excellent gas permeation stability and high tolerance by forming a gas-permeable tissue comprising silica, chromia and alumina in specific amounts, respectively, and binding portions used as aggregates with a component having a high melting point of specific temperature or higher. SOLUTION: This refractory for blowing an inert gas has a gas-permeable tissue comprising a refractory material containing 1-5 wt.% of silica, 1-5 wt.% of chromia and 90-98 wt.% of alumina, wherein portions used as aggregates are bound with a component having a high melting point of >=1,800 deg.C. The pore diameter distribution of the refractory has a <=75 μm pore diameter rate of 25-50%. The refractory is produced by adding a binder such as a phosphoric acid compound to a mixture containing corundum, chromium oxide, silica, mullite, etc., in a prescribed particle size and in a mixing ratio, kneading the mixture together with water, press-molding the kneaded product, and subsequently sintering the molded product at 1,800-1,860 deg.C. The formed refractory has gas-permeable tissues 21, 22 in which aggregates 29 are bound through a high melting point component having a melting point of >=1,800 deg.C and further in which gas-permeable pores are formed from spaces 31 among the aggregates 29. |
