A Scheme for Improving Bioleaching Amount of Treatment and Leaching Concentration of Electroplating Slag

Electroplating sludge is an inevitable solid waste generated from an electroplating wastewater treatment. It contains high concentrations of a variety of valuable toxic metals, which must be disposed of in an environmentally friendly manner. In this study, comparison of heavy metal recovery from electroplating slag by chemical leaching and bioleaching was explored. Studies have shown that five kinds of metals can be effectively mobilized under acid conditions. We found bioleaching to be an efficient method by which metals in electroplating slag could be mobilized at a pulp density of 12% in a batch test. The recovered close to 100% of Zn, Cr, Cd, Ni, and Cu by bioleaching in each of the bioleaching experiments. The extracted (in mg/L) 6000, 2400, 1200, 600, and 600 of the respective metals. The study demonstrates that the integrated bioacid regeneration-coupled bioleaching process significantly enhances leaching efficiency, while reducing sulfuric acid consumption required for metal dissolution.