Abstract

Acid mine drainages (AMD) are the most harmful and chemically complex aqueous waste produced by the mining industry, causing contamination of fresh water sources, affecting human communities and the environment surrounding the mine facilities. Nowadays, AMD treatments use a high amount of reagents that produce a considerable quantity of waste, limiting the opportunity for recovering valuable metals. AMD typically can contain high quantities of copper that could be potentially recovered as a saleable product. Accordingly, this study proposes a novel combination of metal sulfide precipitation with membrane microfiltration process to clarify and separate those previously formed metal sulfide, focused on enhancing the copper recovery and the performance of clarification, evaluated in terms of turbidity of treated solution and separation rate. Three synthetic AMD were assessed, varying the copper content in a mono tubular ceramic membrane of 0.14 mu m pore size. Results were promising: flux values were higher than 0.1 L/m2s, at least one order of magnitude higher with respect to other matrices. Copper recoveries were closer to 100% and turbidity values in the treated solution were lower than 2 NTU for sulfide stoichiometric dosages of 120%. Hence, this method could be an excellent alternative to efficiently recover copper from AMD.