Metal recovery from a copper mine effluent by a hybrid process

Selective removal of metal ions was examined in the present paper integrating in the same tank/cell two effective removal processes. This was accomplished taking advantage of flotation, for membranes cleaning among others, combined with microfiltration by submerged membranes. The operation of the hybrid cell was investigated in depth applying initially a metal sorption process using suitable bonding agents and solid/liquid separation of the fine particles downstream. Dispersed-air flotation was capable for a preliminary solids recovery of the order of 90%, with the Cu content in the froth concentrate approaching 6%. The investigation of this innovative idea was focused ultimately to a pilot-scale study at a Bulgarian mine wastewater with promising experimental results, following the development of the separation technique at the laboratory. It was found that the residual heavy metal (Cu, Mn, Fe and Pb) concentrations in the membranes permeate were below 0.05 mg L−1.