Solvent extraction-based recovery of Co from leach solutions of Cu[sbnd]Co ores using a Mextral 6103H-naphthenic acid- isooctanol system

Abstract

A Mextral 6103H–naphthenic acid–isooctanol synergistic extraction system was used for the selective separation of Co from pre-treated leach solutions of CuCo ores and the extraction performance, the extraction/stripping kinetics, and the phase separation properties of this system were determined. At pH 4.0, Co was selectively extracted from the feed solution containing Co, Ni, Zn, Mg, Mn, and Ca. The Co-loaded organic phase was easily stripped with a solution containing Co (100 g/L) and H2SO4 (40 g/L) at an O/A ratio of 5:1 and 25oC. Based on the McCabe-Thiele plots for Co extraction, scrubbing and stripping, tests involving simulated batch counter-current extraction (two stages), scrubbing (two stages) and stripping (two stages) were performed. A Co extraction efficiency of 99.7% (over two extraction stages) was obtained, while nearly all Mg, Mn, and Ca remained in the raffinate. The two-stage scrubbing of the co-extracted loaded organics resulted in the efficient removal of Zn (88.3%), Mn (95.2%), Mg (94.0%), and Ca (92.0%). The two-stage stripping of Co had an efficiency of 99.1%. The stripping liquor contained low levels of Zn (3.4 mg/L), Ni (0.2 mg/L), Mn (2.4 mg/L), Mg (1.2 mg/L) and Ca (0.8 mg/L), with the resulting Co purity equaling 99.98%. Thus, the developed process holds great promise for the selective recovery of Co from the leach solutions of CuCo ores containing multiple metals