Kinetics of reduction of copper oxide from liquid slag using carbon

Recent trends in oxidative continuous smelting of copper concentrates are leading to higher copper loss in slag (up to 6%) mostly in the form of copper oxide. Reduction of copper oxide from slag is further carried out in slag cleaning furnace with carbon as reductant. In the present study, reduction of copper oxide from a liquid slag by carbon was investigated. The experiments were carried out in a resistance heating furnace using a graphite lined alumina crucible. The influence of various parameters such as temperature, initial CuO0.5 content in the slag, and stirring of the melt by argon, on the reduction kinetics Of CuO0.5 was studied. Based on the results obtained from this investigation the probable rate controlling mechanism was proposed. Results suggest that the reduction reaction was first order with respect to the concentration of CuO0.5 and was controlled by chemical reaction at the slag/graphite interface. Activation energy for the reduction of CuO0.5 by carbon was estimated to be 188.4 kJ/mol, which is comparable with the activation energy of the catalyzed Boudouard reaction.