ENVIRONMENTALLY FRIENDLY ROUTE TO COPPER PRODUCTION: SULFIDATION AND LEACHING OF CHALCOPYRITE CONCENTRATES

摘要

In the production of copper from chalcopyrite (CuFeS_2) concentrates by the smelting and converting technology, the ambient pollution with gaseous SO_2 and toxic metals such as arsenic compounds is still a serious problem, especially in the converting step due to the batch nature of the conventional Peirce Smith process. Non-SO_2 emitting alternatives are leaching processes. However, few of them have had a limited industrial application and they are not very effective in discarding safely the toxic impurities. A combination of pyro-hydrometallurgical methods: the sulfidation of chalcopyrite and subsequent leaching of the sulfidized material is a non-polluting alternative to treat not only clean chalcopyrite concentrates but also complex chalcopyrite-enargite concentrates. In this article, this alternative is discussed concerning the thermodynamics and kinetics of the sulfidation of chalcopyrite with gaseous sulfur. The kinetics of the leaching of the sulfidized concentrate in an H_2SO_4-NaCl-O_2 system is also discussed.