Patent ID: 6692628
Filing Date: 2004-02-17
Classification: C22B,C25C,Y02P

Abstract:
A method for the electro-winning of copper comprising:providing electrodes in an electrolyte comprising a copper-enriched aqueous solution of a copper sulfate-sulfuric acid mixture containing iron (III) as an impurity and passing current therethrough to effect extraction of copper by electroplating of the copper from the electrolyte; the extraction of the copper causing a relative build up in the level of the iron impurity in the electrolyte; after extracting copper, removing at least a part of the electrolyte solution; removing the iron (III) impurity from the aqueous sulfuric acid electrolyte solution containing the iron impurity by: contacting the removed electrolyte solution with an anionic strong base solid ion exchange medium in which the medium binds the sulfuric acid in preference to the iron (III) ions to form a solid/liquid admixture, wherein the ion exchange medium is comprised of an insoluble cross-linked polymer having a plurality of quaternary amine groups (N::) as the exchanging group; contacting the electrolyte solution with a sufficient amount of ion exchange particles for a time period required to solid phase-bind the sulfuric acid to leave an aqueous phase containing the iron impurity; separating the solid and liquid phase; extracting the iron impurity from the liquid phase; removing the sulfuric acid from the solid ion exchange medium; and returning at least part of the sulfuric acid and the liquid phase after extraction of the iron impurity to the electrolyte solution for further electrolytic plating of the copper.