A synergistic solvent extraction system for separating copper from iron in high chloride concentration solutions

A synergistic solvent extraction (SSX) system consisting of Versatic 10 and LIX 63 has been developed to separate copper from iron in high chloride concentration solutions and to transfer the extracted copper to a sulphate solution for recovery by conventional electrowinning. The SSX system is able to selectively extract copper over iron and other impurity metals from chloride solutions in extraction stages. The co-extracted iron and chloride in the loaded organic solution are scrubbed in two separate scrub circuits. A spent electrolyte is used to strip the copper from the scrubbed organic solution for conventional copper electrowinning. A process flow sheet from leaching with chloride solutions to copper conventional electrowinning is proposed.It is proposed that in high chloride concentration solutions, copper exists as neutral molecule of CuCl2, which forms complexes with the organic components of the SSX system via a solvating mechanism. After scrubbing the chloride from the organic system with water at an appropriate pH, the copper is proposed to be re-extracted via a cation exchange mechanism by the same organic system.

► An SSX system is developed to separate Cu from Fe in chloride solutions.
► The co-extracted iron and chloride are scrubbed in two separate scrub circuits.
► The SSX system transfers the Cu to sulphate solution for recovery by electrowinning.
► A process flow sheet from Cu chloride leaching to Cu electrowinning was proposed.