Separation of nickel and cobalt from sulfate solutions by solvent extraction

摘要

Sulfate solutions containing nickel and cobalt ions are treated by solvent extraction to provide a nickel raffinate with a high Ni:Co ratio and a cobalt raffinate with a high Co:Ni ratio and with low recycle of cobalt by treating the solution with a cobalt extractant to provide a nickel raffinate of high Ni:Co ratio and a loaded extractant, acid stripping the loaded extractant to provide a cobalt sulfate solution containing some nickel and a regenerated cobalt extractant, treating the cobalt sulfate solution with a nickel extractant to provide a cobalt raffinate with a high Co:Ni ratio and acid stripping the loaded nickel extractant to regenerate the extractant and to provide a recyclable sulfate solution containing only a small proportion of the original cobalt.