Elemental copper recovery from e-wastes mediated with a two-step bioleaching process

Abstract

Copper recovery from printed circuit boards (PCB) from waste mobile phones was investigated using a two-step bioleaching process. The method consists of a first step where Fe(II) ions are biologically oxidised to Fe(III) by Acidithiobacillus ferrooxidans. Later, Fe (III) ions are put in contact with the PCBs for copper solubilisation. At the conditions tested in the present work, the Fe(II) bio-oxidation (first step) was almost completed in 48 h. Two different methods (filtration and sedimentation) for biomass separation before the second step were tested. No significance differences between both separation methods were observed in terms of the overall process efficiency. In both cases, using 7.5 g/L of e-waste concentration, copper recovery of 95–100% were obtained in only 48 h. In order to test an inexpensive and environmental friendly method to recovery the copper from the leachate solution, cementation of Cu (II) with metallic iron was performed. The copper powder obtained had purity of 64.8%.