| 摘要 |
PURPOSE:To reduce chromium ore at a low cost and high degree by adding a binder to a pulverized powder mixture composed of the chromium ore and carbonaceous reducing agent, molding the mixture to a lump shape, forming a protective film on the surface and subjecting the molding to a heating treatment in a tunnel kiln. CONSTITUTION:The pulverized powder mixture preferably sized about <=100mesh is prepd. by mixing the chromium ore powder and carbonaceous reducing agent powder such as coke and coal. The compounding ratio of the above-mentioned carbonaceous reducing agent is specified to the theoretical ratio or the ratio slightly in excess thereof. The binder such as bentonite or CMC is added to the pulverized powder mixture and the mixture is molded to the lump shape sized about 10-300mm. The protective film which prevents the intrusion of an oxidizable combustion gas is formed by using pulverized powder such as Cr2O2, SiC and fly ash on the surface of the resulted molding. The coated molding is heated to 1,200-1,500 deg.C and reduced in the tunnel kiln. The reduced chromium ore having high reducibility of about >=80% is thus obtd.
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