Extraction of copper, zinc, nickel and cobalt in acid oxidative leaching of chalcopyrite at the presence of deep-sea manganese nodules as oxidant

This paper presents results of investigation on leaching of chalcopyrite in hydrochloric acid medium in the presence of deep-sea manganese nodules. The effects of temperature, acid concentration and charge composition were investigated. Chalcopyrite did not dissolve independently, but underwent oxidative leaching in the presence of deep-sea nodules containing manganese oxide mostly via chlorine gas liberated in reaction of manganese with HCl. Because zinc, nickel and cobalt as well as copper are present in deep-sea manganese nodules, also behaviour of these metals during leaching was studied. The metal recoveries of these metals were higher in case when mixture of nodules and chalcopyrite was used as an initial charge for leaching. After dissolution of both chalcopyrite and nodules, the metals pass into solution very quickly. Later on, the process begins to slow down or even stops and metal values vanish from the solution. This phenomenon occurs as a result of the change in the reversible oxidation potential followed by precipitation of some solid metallic compound.