Platinum, palladium and gold leaching from magnetite ore, with concentrated chloride solutions and ozone

• DOI: 10.1016/j.hydromet.2016.06.009
• Publication Date: 2016-06-26T23:09:07Z
• Authors: Robinson Torres; Gretchen T. Lapidus
• Keywords: Platinum group; Aqua regia; Gold cyanidation

Abstract A leaching process for platinum contained in a magnetite ore was studied, as an alternative process to cyanidation and aqua regia digestion. The proposed process employs concentrated chloride solutions and ozone gas injection during the entire leaching process. The effect of pH, chloride concentration and temperature was analyzed. Under atmospheric pressure at a temperature below 30 °C, after 3 h of leaching, metal extraction > 90, 70 and 50% was attained for Pt, Pd and Au, respectively. The apparent activation energies for Pt, Pd and Au were found to be 44, 39 and 23 kJ/mol, respectively. The magnetite mineral matrix was not attacked during the leaching of platinum group metals.