Kinetics of cobalt oxidation in solvent extraction by 8-quinolinol and Kelex 100
Abstract During solvent extraction by 8-quinolinol and Kelex 100, Co(II) chelates are irreversibly oxidized, by atmospheric oxygen, to Co(III) chelates which are poorly strippable. This oxidation which is first order with respect to Co(II) is influenced by organic phase features: Strong donor compounds stabilize Co(II) by formation of mixte complexes and considerably reduce the oxidation rate, the order of efficiency being: octanol Acidic compounds also stabilize Co(II), the order of efficiency being: “VERSATIC” 10 = acetic acid = benzoic acid