Extraction of cobalt(II) from an ammonium nitrate-containing leach liquor by an ammonium salt of di(2-ethylhexyl)phosphoric acid

摘要

A hydrometallurgical process that involves solvent extraction and selective precipitation has been used to selectively recover Co~(2+) from an aqueous filtrate containing mostly Co~(2+) NH_4~+ and NO_3~- ions and trace amounts of Pt~(2+), Al~(3+) and Fe~(3+) ions. The effect of pH on the precipitation efficiencies of Al~(3+) and Fe~(3+) ions from the leach liquor was investigated. Solvent extraction exhibited good performance in terms of both Co~(2+) and Pt~(2+) ions extraction efficiency and phase separation when ammonium salt of di(2-ethylhexyl)phosphoric acid was used as an extractant in the presence of a tributylphosphate modifier. Cobalt was stripped from the organic phase with nitric acid to yield cobalt nitrate.