Galvanic bioleaching of chalcopyrite with additional power recovery

• Galvanic bioleaching separates leaching and bacterial oxidation into two parts. • Cl - addition and higher temperature were used to dissolve chalcopyrite . • 81.8 % of Cu extracted from chalcopyrite in 24 h. • Fe 3+ /Fe 2+ regeneration and power recovery were achieved. • The formation of a sulphur/jarosite passivation film was inhibited. Chalcopyrite, the primary copper ore, is difficult to treat by bioleaching. Although chloride ions and relatively high temperatures can catalyze this process, they can also significantly inhibit microbial metabolism. In this work, galvanic bioleaching (GalBio) of chalcopyrite was investigated by separating the leaching and microbial regeneration of the oxidant into two chambers. Therefore, stricter leaching conditions were used in the negative chamber with 0–1.5 mol/L NaCl and 60–90 °C for chalcopyrite dissolution, while the biological metabolism of the positive chamber was maintained under optimal conditions. In addition, power recovery was assumed with an external resistance of 0.5–50 Ω during the GalBio process. Compared with the control groups, the GalBio system in the presence of NaCl improved Cu extraction by 58–70 %, with a leaching time of only 24 h. In addition, a stable current of ∼80 mA and a maximum electrical energy production of 113.6 kW h/t Cu leached were achieved. A combination of the solid characterization results (XRD, SEM and XPS) revealed that the GalBio system prevented the formation of jarosite , and the addition of NaCl resulted in the “passivation” film being loosely porous, effectively facilitating the access of reactants to unreacted chalcopyrite cores. The results obtained may provide new ideas for Cu extraction from chalcopyrite and help promote the green development of the industry through the recovery of electricity. However, improving the efficiency of electron transfer between the two electrodes in the anode and cathode chambers, and preventing intermediates and mineral particles from clogging the internal fluid flow channels of the device through more optimized structural design and material application, are potential issues to focus on as the GalBio process is scaled up and industrialized.