A low temperature chlorination-volatilization process for the treatment of chalcopyrite concentrates

Chlorination of two chalcopyrite concentrates with Cl-2+N-2 was investigated under isothermal conditions in the temperature range of 20-750-degress-C using boat experiments. The effect of gas flow rate, chlorine content of the gas mixture and residence time on the physico-chemical characterization of the reaction products. The chlorination of chalcopyrite concentrates started at room temperature generating chlorides of Cu, Pb, Zn, Fe, and S. The reaction of chlorine with sulfides is almost complete at about 300-degrees-C and the overall reactions is exothermic. At this temperature, the valuable metal chlorides were concentrated in the chlorination residues, while those of iron and sulfur were volatilized. A flow sheet is proposed for the selective chlorination of chalcopyrite concentrates at low temperatures. Such flow sheet could be considered as an attractive route for the sulfide concentrates' treatment without SOx emissions. It could be also regarded as energy saving with respect to the classical pyrometallurgical routes. (C) 2001 Elsevier Science B.V. All rights reserved.