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 << D_{LIX 84-IC} + D_TBP and negative values of ∆D. The highest separation (β_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 ΔH° value of 5.4 kJ∙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∙L⁻¹ H₂SO₄ solution at the unit phase ratio.

KEYWORDS:

• Solvent extraction
• Ammoniacal leach liquor
• Laterite ore
• Metal ammine complexes
• Antagonistic extraction

Acknowledgments

This work was supported by the Brain Pool Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (grant no. 2021H1D3A2A01100016) and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (project no. 2020R1I1A1A01074249).

Disclosure statement

No potential conflict of interest was reported by the authors.

Author contributions

S. Ilyas: Conceptualization, Data curation, Funding acquisition, Writing – original draft, Writing – review and editing. R.R. Srivastava: Conceptualization, Data curation, Formal analysis, Validation, Writing – original draft. S. Jin: Writing – Literature survey, formatting. H. Kim: Supervision, Funding acquisition, Writing – review and editing.

Additional information

Funding

The work was supported by the National Research Foundation of Korea [2020R1I1A1A01074249, 2021H1D3A2A01100016]