Extraction Technology of Purification of Sulfate Nickel Solutions of Impurities with the Use of Dialkylphosphine Acid

The data of laboratory investigations of the removal of impurities (Fe, Cu, Zn, Mg, Ca) from sulfate nickel solutions are presented. It is shown that Cyanex 272[di(2,4,4-dimethylpenthyl) phosphinic acid] is the most efficient extractant. For two extraction steps by a nickel form of Cyanex 272 from a solution (after iron purification) that contained: Ni 120-130, Cu 0.8-1.0, Zn 3.0-4.0, Mg 1.5-2.0, Ca 0.4-0.8, and Fe 0.01-0.02 g/l, raffinates of the following composition are obtained: Ni 120-130, Cu, Zn, and Fe <= 2 x 10(-3) each, Mg <= 0.1, and Ca 0.2-0.3 g/l. Purification of raffinates of organic impurities (extractant, diluent) after extraction is performed on the DAK-activated charcoal. Reextraction of metals and, correspondingly, extractant regeneration, is easily performed by solutions of mineral acids (H2SO4 and HNO3). Extraction of nickel from the solution at the extraction step is >= 99.8%.