Removal of Copper from Copper-smelting Slags through Chloridizing Roast

Abstract

The copper in copper-smelting slags can be removed effectively by means of chloridizing roast process, which is beneficial to recover iron from the copper-smelting slags. Thermodynamic analysis was carried out to characterize the performance of copper and iron during the chloridizing roast process. It follows that in a certain range of processing parameters, the copper removal rate can be enhanced with the increasing ing temperature and time for the process, and the increasing amount of CaCl_2 addition and FeSO_4. When the addition amount of FeSO_4 was higher than 0.15(mass ratio of FeSO_4 to copper slags), SO_2 was produced excessively and the(FeO) content in the reaction bed increased quickly. The generated FeO can be chlorinated easily, thereby caused an obvious increase of iron loss and decrease of the copper removal rates. The copper content in the slags decreased from 1.06% to 0.11% after a chloridizing roast treatment at 1373 K for 30 minutes, with an O_2 flow velocity of 0.40 L·min-1and an addition amount of CaCl_2 of 0.20(mass ratios of CaCl_2 to copper slags) and FeSO_4 of 0.15(mass ratios of FeSO_4 to copper slags).