Extraction of metals from saprolitic laterite ore through pressure hydrochloric-acid selective leaching

In this study, pressure hydrochloric-add selective leaching was used to leach Ni and Co from saprolitic laterite ore on the basis of potential-pH diagrams constructed for Fe-Si-Cl-H2O and Ni-Si-Cl-H2O systems. The leaching of Ni, Co, Mg, Mn, and Fe was investigated under various conditions. The results showed that the optimal output was obtained under the following conditions: leaching temperature of 150 degrees C, HCl concentration of 350 g/L, liquid to solid ratio (I/s) of 1.0, and leaching time of 90 min. The saprolitic laterite and leached residue were characterized via X-ray diffraction analysis, infrared spectrometry, and mineral liberation analysis. The related acid leaching mechanism was analyzed based on the results, and the kinetics of the leaching process was discussed. The results of this study suggest that pressure hydrochloric-acid selective leaching is a viable method for efficiently leaching Ni from laterite ores. (C) 2015 Elsevier B.V. All rights reserved.