Advances in Tank Bioleaching of Low-Grade Chalcopyrite Concentrates

The focus of this paper is on the treatment of low-grade chalcopyrite-pyrite containing concentrates. The bioleaching of chalcopyrite is a major challenge due to slow copper leach kinetics and poor copper extractions. Bioleaching tests were carried out in bench-scale piloting facilities, comprising fully controlled multi-stage continuously operated reactor systems using moderate thermophile and thermophile consortia under both uncontrolled and controlled redox potential conditions. Bioleaching operating conditions and control strategies have been identified, which have the potential to significantly increase the rate of Cu leaching and to reduce process costs by allowing control of the amount of pyrite oxidised.