Bioelectrochemical-assisted bioleaching of chalcopyrite: Effect of pulp density, anode material, and sliver ion

Abstract

Chalcopyrite bioleaching has developed rapidly because of the advantages such as environmental protection, low capital investment and simple operation, but its application has been limited by the slow reaction rate and other problems. Bioelectrochemical system (BES) as a promising wastewater treatment technology could solve the problem of reaction abort due to insufficient electron acceptors inside the mineral heap. In this study, the effect of pulp density, anode material and silver ion on the copper bioleaching were carried out. Experimental results showed that the maximum bioleaching efficiency (1.70 ± 0.18%) in 11 d was achieved at a pulp density of 1% with the application of titanium-silver anode and the assistance of BES. BES promoted the bioleaching of Cu mainly by promoting the bacterial reproduction and the Fe2+ production from the chalcopyrite. Moreover, the introduction of BES promoted the release of Ag+, further enhancing the bioleaching of Cu by 1.5 times (187.7 ± 18.1 mg/L vs. 120.9 ± 22.2 mg/L). In addition, the inhibition of conductive silver glue on the copper bioleaching and bacteria was alleviated by the BES. As an anode material, carbon cloth couldn't improve the leaching of Cu as compared to titanium foam, but it could increase the electron transfer efficiency.