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

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.

Automated summary

In this study, the complete separation of copper over nickel from an ammoniacal leach liquor of nickel laterite ore was achieved using a combination of phenolic oxime (LIX 84-IC) and tributyl phosphate (TBP). The antagonistic effect of TBP was confirmed by the distribution coefficients and negative increment D values. The highest separation was obtained at a molar ratio of LIX 84-IC:TBP = 0.4:0.6 and an organic-to-aqueous phase ratio of 1, with a separation factor (beta(Cu/Ni)) of >1329.