Alternative Lixiviant for Copper Leaching from Chalcopyrite Concentrate

Abstract

This study investigated leaching kinetics by alternative lixiviants for copper leaching from chalcopyrite (CuFeS2), the most abundant copper resource in the world. As a refractory sulfide mineral, chalcopyrite shows low copper extraction due to passivation on chalcopyrite surface. Also, decrease of copper grade with high portion chalcopyrite requires the alternative leaching procedure to increase copper recovery. Therefore, alternative lixiviants such as sulfurous acid and methanesulfonic acid (MSA) were tested for both concentrate and low grade ore to enhance copper extraction. Also, an oxidant, hydrogen peroxide, was compared to ferric to find out the improvement of leaching kinetic. In concentrate leaching tests, 30 g/L MSA showed the highest copper extraction (47{\%}), compared to other lixiviants at 75 {\textdegree}C. Periodical H2O2 addition enhanced copper extraction, and above 90{\%} of copper extraction was observed within 96 h by periodical addition of 0.6{\%} H2O2 at 75 {\textdegree}C. The activation energy of chalcopyrite leaching by MSA and H2O2 achieved 40 kJ/mol, which is chemical reaction control. The results of low grade ore leaching tests indicates that no significant difference among lixiviants (H2SO4, H2SO3 and MSA) with ferric was observed, all of which achieved around 37{\%} within 24 h at room temperature. However, significant increase of copper extraction (>80{\%}) was observed at both 20 g/L MSA and 10 g/L H2SO4 conditions by the addition of 10{\%} H2O2.