SEPARATION AND RECOVERY OF COBALT(II) AND NICKEL(II) FROM SULFATE-SOLUTIONS USING SODIUM-SALTS OF D2EHPA, PC-88A AND CYANEX-272

Separation and recovery of divalent cobalt and nickel ions from sulpha te solutions containing 0.01 M metal ions each and 0.1 M Na2SO4 have b een carr.ed out using 0.03, 0.05 and 0.06 M sodium salts of D2EHPA, PC 88A and Cyanex 272 in kerosene. The percentage extraction of metal io ns increased with increasing equilibrium pH. Cobalt aias preferentiall y extracted over nickel with the extractants; however, 0.05 M NaPC 88A and NaCyanex 272 were found to be suitable for the separation study. The highest separation factor was achieved with 0.05 M NaCyanex 272 at equilibrium pH 6.85. Recovery of cobalt from cobalt-nickel bearing so lution was achieved with 0.05 M Cyanex 272 and PC 88A at equal phase r atio followed by their stripping with 0.02 M H2SO4 at O:A ratio of 2:1 . Nickel was extracted from the cobalt-free raffinate in two stages at equal phase ratio with PC 88A and Cyanex 272 followed by their stripp ing with 0.02 M H2SO4 at O:A ratio of 4:3 and 2:1, respectively. (C) 1 998 Elsevier Science B.V. All rights reserved.