COPPER LEACHING FROM PRIMARY SULFIDES: OPTIONS FOR BIOLOGICAL AND CHEMICAL EXTRACTION OF COPPER

The primary sulfide minerals of copper have posed challenges for effective leaching aimed at direct copper extraction, particularly chalcopyrite, which tends to passivate under various oxidative leaching conditions. Over the past 10-15 years, diverse biological and chemical leaching methods have been developed to address this passivation issue, with several of these processes now nearing or achieving commercial viability. Notably, the BIOCOP™ process has reached commercial production at the Alliance Copper plant in Chile. Additionally, Total Pressure Oxidation technology has been utilized by Phelps Dodge at their Bagdad site in Arizona. The Mt. Gordon and Sepon copper processes have integrated autoclave techniques into their metallurgical circuits, with the former focusing on copper leaching and the latter on acid and ferric sulfate production for atmospheric leaching. Other processes, including the CESL copper process and PLATSOL™ technology, are also in various stages of feasibility studies and application in locations such as Brazil and Minnesota, USA. The increasing options for copper recovery from primary sulfides, including heap leach methods, signals a transition in copper extraction strategies, fostering a comparison of the mechanisms and efficacy of these emerging leaching processes.