Removal of Cobalt(II), Zinc(II) and Copper(II) from Nickel Sulphate Solutions by Solvent Extraction

摘要

The purification of nickel sulphate solutions from microquantities of Co(II), Zn(II) and Cu(II) by means of extractants of various types was studied. The optimal conditions for removal of Co(II), Zn(II) and Cu(II) from NiSO_4 solutions with respect to equilibrium pH, phase contact time and the type of extractant used were determined. The best results for purification of NiSO_4 from Co(II) were obtained with Hostarex F-3541 and Aliquat 336 in the thiocyanate form. In purification of NiSO_4 from Zn(II) extractants such as D2EHPA, Hostarex F-3541, Hostarex PO-224 and Aliquat 336 thiocyanate could be used but the most effective was Hostarex PO-224 (alkylphosphonic acid ester of R-PO(OR)_2 type). This extractant is selective for zinc (II) (recovery >90%) and can be used in NiSO_4 purification from Zn(II) on a macro scale. However, chelating extractants (Kelex 100, LIX-26, LIX-64N, LIX-65N, LIX-70, LIX-84, LIX-622, LIX-860 and LIX-984) can also be used for selective purification of NiSO_4 from Cu(II). The copper content in the purified nickel sulphate could be decreased to a level of 10_(-4)% using these extractants.