Studies on the extraction process of nickel(II) sulphate purification using Cyanex 272

Extractive purification of macroquantities of NiSO4 from microquantities of Co(II), Zn(II), Cu(II), Mn(II) and Fe(III) using Cyanex 272 was studied. The optimum conditions of Co(II) removal depending on equilibrium pH value, phase ratio and extraction temperature were determined. The most effective results were obtained using a two-stage extractive purification of Ni(II) sulphate from Co(II) at a phase ratio of 1:1, equilibrium pH > 6 and 323 K. Under these conditions the Co(II) content in the purified NiSO4 decreases several hundred times compared to the initial content. Nickel sulphate purified in this way contains <0.001% Co, <0.0001% Zn, <0.00005% Fe, <0.00005% Cu and < 0.00005% Mn.