Bioleaching vs. Chloride Leaching: Real Advantages and Drawbacks for Primary Sulfides

Currently the vast majority of the world’s copper is obtained through sulfide mineral processing. Among the copper sulfides, chalcopyrite is the most economically relevant due to its abundance. Therefore, several technologies have been developed in order to achieve an efficient copper extraction from copper sulfides. Among these developments, the hydrometallurgical options of bioleaching as well as chemical chloride leaching are prevailing for secondary copper sulfides due to their good results at lab, pilot and industrial scale. Examples such as the Bacterial Thin-Layer technology developed by Minera Pudahuel in the 80s (CL Patent 32025), as well as the Cuprochlor® process developed by Minera Michilla (CL Patent 45163), coming to the more recent “Heap leaching method” (US Patent WO2014030048A1) and the mixed version of the “Chloride method for bioleaching” patented by BHP Billiton (US Patent WO2012001501A1), are some examples that are currently being extended to the efficient copper extraction from chalcopyrite. In this work, we have compared at lab-scale BioSigma’s bioleaching technology and the industrial state-of-art chloride leaching for a mainly chalcopyritic copper sulfide ore. The metallurgical and microbial results, and the economical evaluation and comparative analysis clearly show that bioleaching presents several advantages compared to chloride leaching, being the biotechnological option more cost-effective and therefore industrially applicable.