Copper recovery from the tailings of slag flotation by leaching and roasting

Abstract

The sulphuric acid and the hydrogen peroxide leaching and roasting with/without addition of NaCl and Na2SO4of tailings of Black Sea Copper Works Flotation Plant (in Turkey) were studied. The native copper, covellite, chalcosite, digenite, and bornite as primarily copper minerals, fayalite, magnetite and pyrite, as the iron minerals of tailings were determined. The copper extraction, which reaches to 55.77% at 75°C with 144 g/L H2SO4, increases with increasing acid concentration and temperature in sulphuric acid leaching. In hydrogen peroxide leaching, the copper extraction increases with increasing H2O2 concentration, the effect of temperature was not very important. For example, it was 49.30% at 95 °C, while the iron extraction was stayed in negligible level. The roasting products, called calcine, were leached with water and also with sulphuric acid solution at pH 1.4. The copper extraction of 79% at 550°C, 72% at 650°C and 65% at 700 °C were obtained for roasting without reagent addition, chlorination roasting with NaCl and sulfatizing roasting with Na2SO4, respectively.