Elevated pressure operation in the cuprion process

Abstract

A process in which copper, nickel, cobalt and molybdenum are recovered by direct leaching of comminuted raw manganese nodules with an aqueous ammoniacal leach solution containing cuprous ions. During the process cuprous ions are consumed and are oxidized to cupric ions. The cuprous ions are regenerated by reducing the cupric ions with a reducing gas. An improvement is disclosed which results from increasing the pressure of the reducing gas. This increased pressure facilitates maintaining a high cuprous ion concentration in each reaction vessel, by increasing the rate at which the cuprous ions are regenerated from the cupric ions without affecting the rate at which the metal values are recovered from the nodules, which in turn, increases the efficiency of each reactor thus enabling the size of reactors to be reduced. In one important embodiment of the invention, the reducing gas is sparged into a series of reaction vessels at increased pressure while the manganese nodules are injected into several vessels simultaneously. This increased pressure of the reducing gas together with the multiple point injection of the manganese nodules greatly increases the efficiency of the process. In another important embodiment of the invention as the reducing gas is sparged into the reaction vessels under increased pressure sufficient heat is removed from the slurry leaving each reaction vessel so that all reaction vessels operate at substantially the same temperature within the range of 35.degree.-55.degree. C. By operating within this temperature range, nickel and cobalt solubilization within the reaction vessels is improved.