Alkali metal mercaptide solvent extraction of cobalt, nickel

Abstract

A novel class of extractants and a method of using the extractants in the hydrometallurgical recovery of nickel and cobalt metal. The extractants comprise a water immiscible organic solvent system containing solubilized mercaptide anions. In an important embodiment of the invention, the mercaptide anions are generated by solubilizing an alkali metal mercaptide in a polar organic solvent capable of solvating alkali metal ions. Alternatively, an organic solution of a mercaptan is exposed to an aqueous solution of NaOH or KOH to produce the mercaptide anion. The extractants are used by being contacted with cobalt, nickel, or cobalt and nickel pregnant aqueous solutions. On mixing, the cobalt and/or nickel values are taken up by the organic as cobalt or nickel mercaptides. These may then be stripped of cobalt and nickel by treatment with an aqueous alkaline solution and carbon monoxide.

Dependencies are inferred from the claim text.