Liquid-liquid separation of copper and nickel ammine complexes using phenolic oxime mixture with tributyl phosphate

Abstract

In the present study, a complete separation of copper over nickel has been studied from an ammoniacal leach liquor of nickel laterite ore generated via the Caron process. For this purpose, a phenolic oxime (LIX 84-IC) used as the extractant molecule was mixed with tributyl phosphate (TBP) to inhibit the co-extraction of nickel with copper loading into the organic phase. The antagonistic effect of TBP was confirmed by the distribution coefficients to be D-mix << DLIX 84-IC + D-TBP and negative values of increment D. The highest separation (beta(Cu/Ni)) of >1329 was yielded using the molar ratio of organic mixture at LIX 84-IC:TBP = 0.4:0.6 at an organic-to-aqueous phase ratio of 1. The thermodynamic properties of copper extraction exhibited an endothermic nature with Delta H degrees value of 5.4 kJ center dot mol(-1), indicating the formation of inner-sphere coordination between metal ions and the organic mixture. Further, the stripping of copper from the loaded organic phase was quantitatively achieved by contacting with 1.0 mol center dot L-1 H2SO4 solution at the unit phase ratio.