Hydrometallurgical recovery of high-purity copper cathode from highly impure crude copper

Abstract

A new hydrometallurgical route was investigated in which a pure copper cathode was recovered from crude copper containing high amounts of impurity elements. As an example of crude copper, copper powder obtained from a top submerged lance furnace, which was pulverized by atomization from molten copper, was used. The selective leaching of copper was achieved using an ammoniacal alkaline solution containing divalent copper ammine complexes and ammonium chloride with most impurities (e.g. silver and gold) remaining in the residue. However, some impurities, such as nickel, arsenic, antimony, and lead were dissolved. Purification steps using hydroxyapatite and magnesium chloride were effective at removing lead, antimony, and arsenic. On the basis of these results, copper cathode recovery from crude copper was examined. As a result, a sufficiently pure copper cathode was finally obtained by monovalent copper electrolysis, which indicated the possibility of using this process as a new route for recovering pure copper from highly impure crude copper.