Cobalt(II) cation extraction from solutions containing ethylenediaminetetraacetate and oxalate ions

Abstract

A new approach to extracting cobalt(II) from non-borate and borate solutions of liquid radioactive wastes containing ligands of ethylenediaminetetraacetate and oxalic acid is proposed. The approach is based on the difference in the stability of complexes of organic ions with metals. Substituting iron(III) for cobalt results in almost complete liberation of Co2+ from the complex. Coprecipitation of Co2+ with Fe3+ in the form of oxohydroxides results in the liberation of Co2+ from solution into the solid phase. An excess of Fe3+ cations with respect to Co2+ and an increase of acidity, processing temperature, and aging time of the solutions at the preliminary stage results in complete liberation of cobalt from the solution for pH ≥ 12.