The effect of chloride ions on the dissolution of chalcopyrite in acidic solutions

This paper describes the application of mixed chloride-sulfate leaching at atmospheric pressure for the treatment of a CuFeS2 (chalcopyrite) concentrate. It was found that excellent leaching kinetics exist for solutions containing chloride, while for solutions without chloride, the leaching was very slow. It is believed that the role of chloride is to promote the formation of a more porous sulfur product, thus permitting the dissolution reaction to proceed at a reasonable rate. It was established that temperature and oxygen partial pressure had a substantial effect on the reaction rate, with very good leaching kinetics being obtained at 95 degrees C. At an oxygen pressure of 1 arm, 86% of the copper was extracted in 6 h, and 97% extracted in 9 h. Decreasing the particle size was also found to increase the reaction rate. (C) 2000 Elsevier Science B.V. All rights reserved.