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Chalcopyrite is the primary copper mineral used for production of copper metal. Today, as a result of rapid industrialization, there has been enormous demand to profitably process the low grade chalcopyrite and “dirty” concentrates through bioleaching. In the current scenario, heap bioleaching is the most advanced and preferred eco-friendly technology for processing of low grade, uneconomic/difficult-to-enrich ores for copper extraction. This paper reviews the current status of chalcopyrite bioleaching. Advanced information with the attempts made for understanding the diversity of bioleaching microorganisms; role of OMICs based research for future applications to industrial sectors and chemical/microbial aspects of chalcopyrite bioleaching is discussed. Additionally, the current progress made to overcome the problems of passivation as seen in chalcopyrite bioleaching systems have been conversed. Furthermore, advances in the designing of heap bioleaching plant along with microbial and environmental factors of importance have been reviewed with conclusions into the future prospects of chalcopyrite bioleaching. [ABSTRACT FROM AUTHOR]

Two ore samples, one obtained from a partially leached heap with suspended operations for about four years and the other through sonic drilling of a discarded dump were tested for the amenability/feasibility of copper extraction through reactor and column leaching. Mineralogical analysis of the samples indicated the dominant sulphide minerals to be chalcopyrite and pyrite. Various process parameters such as the effect of acid concentration, time, oxidant, pulverization and temperature were studied for the reactor leaching experiments. A maximum of 91% Cu extraction can be achieved while leaching the pulverized sonic drilled sample at 90 °C for 3 h. On the other hand, column leaching studies at 1 kg scale showed 65–70% Cu extraction with an acid concentration of 2.7% ( v / v ) for both the samples. Sequential leaching of the chemically leached residues of both sonic drilled and heap leached pad sample yielded additional 13.2% and 22.2% Cu, respectively in 20 days of bacterial leaching using a mixed culture of meso-acidophilic bacterial consortium. Column leaching studies showed that the heap leached pad sample was more amenable to leaching than the sonic drilled one. Further, during the downstream processing of the leach liquors, the solvent extraction efficiency was about 95% and the Cu metal deposited by electrowinning was of 99.9% purity. A tentative process flowsheet for the recovery of copper was also prepared. [ABSTRACT FROM AUTHOR]

Dumping of low-grade chalcopyrite encompasses several environmental problems. Despite slow dissolution rate, meso-acidophilic bioleaching is preferred for the extraction of copper from such ores. In the present study, meso-acidophilic bioleaching of a low-grade chalcopyrite in the presence of an acid-processed waste newspaper (PWp) is discussed for the first time. The study illustrated a strong catalytic response of PWp with enhanced bio-recovery of copper from acid-conditioned chalcopyrite. A maximum of 99.13% copper recovery (0.36% Cu dissolution/day) was obtained in 6 days of bioleaching in the presence of 2 gL − 1 PWp in contrast to only 5.7% copper in its absence. FTIR analysis of bioleached residues revealed similar spectral patterns to the original acid-conditioned ore in the presence of PWp, thus indicating less development of passivation layer which was also confirmed through a complementary Raman characterization of the bioleached residues. Further, a reaction mechanism (chemistry) was proposed suggesting the possible role of PWp as the electron donor under oxygen limiting conditions which facilitated microbial reduction of Fe (III). The resulting biochemical changes provided an energy source for the bacteria, thus allowing free flow of electrons through the ore surface, thus contributing towards enhanced bioleaching of copper. [ABSTRACT FROM AUTHOR]