Copper electrowinning from gold plant waste streams

Gold mining industries produce a considerable amount of waste streams containing cyanide and small quantities of copper, gold and other heavy metals. This effluent is usually treated by the AVR process, in order to recycle the cyanide to the leaching operation, however, this process is not efficient for the treatment of stable cyanide complexes. In this paper, the feasibility of copper electrowinning, and eventually residual gold, in a flow-by cell with nickel foam or a reticulated vitreous carbon (RVC) cathode and a cationic membrane was investigated. This process has shown to be environmental-friendly and despite the low average current efficiency and high energy consumption, it permitted the recovery of about 99.6% of the copper and the recycling of 99.4% of cyanide present in the effluent.