Passivation Layer Reduction of Chalcopyrite for Sustainable Extraction of Copper Using Additives Assisted Bioleaching: A Mini Review

Abstract

Nowadays, rich copper ore grades have been exploited and thus mining companies have been increasing their interest to liberate or extract copper from low grade copper ores, mainly from chalcopyrite. However, chalcopyrite ore is the future source of copper, its extraction is hindered due to the formation of passivation film, which consequently inhibiting the leaching efficiency of copper. This review paper sheds light on and critically assesses the recent advancements in passivation film reduction strategies to enhance the recovery rate of copper from chalcopyrite using a synergetic effect of bioleaching and external additives. The microorganisms used in bioleaching enhance the surface property of chalcopyrite due to their unique capabilities of biofilm formation, which enhances adhesion properties. Addition of external additives during the bioleaching improve the microbial activities the ore by providing an active surface for microbial attachment, which boosts dissolution of the chalcopyrite and consequently reduces the formation of passivation film. According to their optimum temperature, microorganisms used in bioleaching classify as mesophilic, moderate thermophilic and extremely thermophilic microorganisms. Mesophilic microorganisms are dominated in bioleaching. This review paper aims as a compiled reference material for future studies towards high recovery of copper from chalcopyrite by modifying the surface property of the ore. Recognizing the rapid advancement and importance of bioleaching in the extractive metallurgy industry (mainly in the extraction of copper from low grade copper sulphide ores), this review paper serves for practitioners as a crucial and technically advanced source for future researches in chalcopyrite bioleaching, techniques for passivation layer reduction of chalcopyrite and current advancements in bioleaching.