Leaching of copper oxide with different acid solutions

In this study, the dissolution of CuO in HCl, H2SO4, HNO3 and citric acid solutions was investigated in a batch reactor employing parameters expected to affect the dissolution rate of copper such as stirring speed, temperature and acid concentration. It was found that 99.95% of copper was dissolved after 14 min with inorganic acids at 0.5 M, 25 °C and l/s = 10 ml/g while more drastic operation conditions were needed to reach the same dissolution efficiency with citric acid solution. Anions seem to be involved in the surface reaction. The dissolution kinetics of CuO was examined according to heterogeneous model and it was found that the dissolution rate was controlled by surface chemical process in all cases.