| In order to recover zinc and obtain a suitable raw material for iron smelting from the copper converter slag, chloridizing volatilizition experiment has been performed using calcium chloride (CaCl₂·2H₂O) and ferric chloride (FeCl₃·6H₂O) as chloridizing agents, and calcium nitrate [Ca(NO₃)₂·4H₂O] and calcium carbonate (CaCO₃) as additives. The effects of the temperatures and times of drying and roasting, and the amounts of chloridizing agents as well as the additives on the removal of zinc from the slag have been tested and discussed experimentally and thermodynamically. By the way, the result on the copper was also added for the purpose of the comparison. The results summarized are as follows; (1) The optimum roasting temperature was found to be 1100℃, an hour of roasting time was good enough for the purpose, and the optimum amounts of calcium chloride (CaCl₂·2H₂O) was 23.37pct. (2) Ferric chloride (FeCl₃·6H₂O) as a chloridizing agent was found to be not effective, the addition of calcium nitrate [Ca(NO₃)₂·4H₂O] together with calcium chloride to the slag was shown the best result, and the addition of calcium carbonate (CaCO₃) to calcium chloride was more effective than calcium chloride only. (3) The slag roasted at 1200℃ was considerably harder than that of 1100℃, and copper was more readily removed from the slag than zinc. Under the optimum conditions, 1.77 pct of zinc in the slag was reduced to 0.03 pct, while 5.43 pct of copper to 0.01 pct. |
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