Copper electrowinning from acid mine drainage: a case study from the closed mine "Cerovo"

Copper removal from acid mine drainage originating from closed copper mine "Cerovo" RTB Bor, Serbia and containing approximately 1.3 g dm(-3) of copper and a very small amount of Fe2+/Fe3+ ions, has been successfully performed by the direct electrowinning method using either a porous copper sheet or carbon felt as the cathode. A cell with a fluidised bed of inert turbulent promoters, also used in this study, may be considered as unacceptable for the purpose view, having a cell voltage between 12 and 14 V. The cells used in the electrowinning experiments were compared in terms of cell voltage, pH and copper concentration. The results showed that it is possible to remove copper successfully from the mine waters with a high degree of electrowinning--higher than 92% and with a satisfactorily average current efficiency (>60%). Depending on the process time and the applied current, a final copper concentration less than 0.1 g dm(-3) was achieved. The specific energy consumption was approximately 7 kWh kg(-1) of deposited copper. A dense copper deposit was obtained when a three-dimensional electrode was used.