| 摘要 |
PROBLEM TO BE SOLVED: To well utilize the effect of corrosion resistance of alumina-carbon unburned refractory brick using alumina particles and to improve spalling resistance and wear resistance of the brick. SOLUTION: The production process of this unburned refractory brick comprises: adding 0.5-5 mass % of at least one metal selected from metal Al, Al-based alloys and metallic Si, to 100 mass % of fire-resistant aggregate which consists of 10-80 mass % of coated magnesia with pitch containing 5-80 mass % of metal Al and/or an Al-based alloy, 1-20 mass % graphite and 10-60 mass % uncoated magnesia: subjecting the resulting mixture to kneading and press forming; and thereafter, drying the formed body by heating it. This vessel for a molten metal is lined with the unburned refractory brick. In the refractory brick, a void is formed in a part of the pitch of each of particles of the pitch-coated alumina by the heating when the molten metal vessel lined with the refractory brick is used, and further graphite having low crystallinity exists in the inner wall of the void. By the presence of such voids and graphite in the inner walls of the voids, any crack propagation due to thermal shock can be prevented from being caused. Further, the metal Al and/or Al-based alloy are reacted with graphite that is a pitch component, at a high temperature, to form aluminum carbide and to increase structural strength of the coating pitch. Thus, oxidation resistance and wear resistance of the brick can be improved. |
