Leaching of Turkish Oxidized Pb–Zn Flotation Tailings by Inorganic and Organic Acids

Abstract

An eco-friendly approach and simultaneous recovery of metals from mine tailings is still a significant challenge. This study investigates the extraction of zinc metal from the Kayseri region oxidized lead-zinc (Pb–Zn) flotation tailings by leaching using three different inorganic acids (HNO3, HCl, and H2SO4) and six different organic acids (citric (CA), oxalic (OA), formic (FA), ascorbic (AA), malic (MA), and tartaric (TA) acids). The effects of acid type and concentration, leaching temperature and time, and solid/liquid (S/L) ratio were studied for maximum Zn dissolution and minimum Pb, Fe, and As co-dissolution at lowest temperature and leaching time. For inorganic acids at 1/10 S/L ratio, 1.0 M H2SO4 and HCl concentrations achieved 92% Zn + 0% Pb + 12% Fe at 40 °C leaching temperature and 60 min leaching time and 92% Zn + 10% Pb + 0% Fe at 80 °C leaching temperature and 30 min leaching time, respectively. For organic acids, at 1/10 S/L ratio and 1.0 M concentration, 92% Zn + 8.3% Pb with malic acid at 80 °C leaching temperature and 180 min leaching time and 91% Zn + 12% Pb with citric acid at 60 °C leaching temperature and 180 min leaching time were achieved. 1.0 M formic acid dissolved about 83% Zn + 2.8% Pb at 80 °C and 180 min leaching time. More than 90% Zn dissolution can be succeeded by using either inorganic acids at 40 °C for 30–60 min leaching time or organic acids at 60–80 °C for 180 min leaching time. Oxalic acid significantly dissolved Fe and As without Zn and Pb dissolution.