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Abstract
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Chalcopyrite, CuFeS2 is the most important mineral of copper, but it is a refractory mineral and does not easily
dissolve in various leaching solutions. In the present work, sulfuric acid solution containing hydrogen peroxide
as the oxidant was used for leaching of chalcopyrite at ambient pressure and temperatures up to 65 °C. Recent
investigations have shown that the presence of some polar organic solvents in the leach liquor increases the
efficiency of copper leaching from chalcopyrite, probably due to stabilization of hydrogen peroxide. A comparative
study on the effect of five polar organic reagents: acetone, ethanol, ethylene glycol, isopropanol and
methanol at exactly the same conditions was done for the first time. It was found that the isopropanol is significantly
more effective than others and ethanol was found to be the weakest. The leaching efficiency surprisingly
increased from below 50% to over 80% by adding 1 mol/L isopropanol into the leaching solution. The
optimized condition for leaching was found to be as: 1.5 mol/L H2SO4, 2 mol/L H2O2, 2 mol/L isopropanol and
temperature of 65 °C with dissolved copper of 85% after 120 min. X-ray diffraction and scanning electron microscopy
proved the formation of elemental sulfur while no evidence of surface passivation of chalcopyrite was
found.
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