Recovery of copper-dominated resources from copper mine drainage by chemical oxidation and sulfur biocycling: A pilot-scale study

Abstract

The copper mine drainage (CMD) formed during copper mining and smelting has the characteristics of being low pH, with a high sulfate concentration and large amounts of metal ions such as Fe, Cu, and Mn. In order to recover copper-dominated many resources from CMD, realize effective control of environmental pollution and avoid the loss of precious resources. The combined process of Fe pretreatment recovery, Cu treatment recovery, and S treatment recovery was established based on H2O2 oxidation, sulfate-reducing bacteria (SRB) reduction, and sulfur-oxidizing bacteria oxidation. A pilot-scale study was carried out with a CMD inlet flow rate of 12 m³/d. Results show that the average Cu2+ removal rate was 99.66%, and the recovered dry matter precipitated (mainly was CuS) copper content was 35.6%. In addition, the average total Fe, Mn and Mg removal rate was 99.46%, 99.10% and 84.08%. And the S2− oxidation rate was above 90% (mainly converted to sulfur). 27.52% Fe precipitated dry matter and 42.9% S, 32.2% Mg, and 13.8% Mn precipitated dry matter were also recovered as by-products. Through high-throughput analysis of the functional and structural changes in the SRB community, showed that indigenous SRB from the copper mine exhibit good adaptability to CMD conditions, with the enrichment and acclimation of SRBs achieving a high level of expression of bioactive. The bottleneck of SRB applied to CMD treatment was solved. Finally, the economic feasibility analysis shows that the combined process treatment CMD can save 58.6% of the cost compared with traditional lime neutralization method, and avoid the sludge treatment cost of 29.03 million USD per year. The above provides engineering practical reference for CMD treatment and resource recovery.