A Study on the Separation of Co( II ), Ni( II ), and Mg( II ) by Solvent Extraction with Cationic Extractants

Solvent extraction and separation of Co (0.8 g/L), Ni (0.3 g/L), and Mg (0.5 g/L) with various cationic extractants (D2EHPA, PC88A, Cyanex 272, Versatic 10, and Cyanex 301) from chloride solutions are investigated. The effects of initial pH, extractant concentration, and saponification degree on the extraction and separation of metals are also studied. Co was preferentially extracted over Mg and Ni by saponified PC88A and Cyanex 272. On the other hand, Cyanex 301 and Versatic 10 exhibited selectivity on the extraction of both Co and Ni over Mg. HCl solution selectively stripped Co over Ni from the loaded Cyanex 301, which made it possible to separate the two metals during the stripping process.