Solvent extraction of copper from chloride solution I: Extraction isotherms

This study was conducted as part of the development of a novel process for copper recovery from chalcopyrite by chloride leaching, simultaneous cuprous oxidation and cupric solvent extraction to transfer copper to a conventional sulfate electrowinning circuit, and hematite precipitation to reject iron. Copper solvent extraction from chloride solution has been studied using four LIX® extractants (LIX84-I, LIX612N-LV, XI-04003 and LIX984N) from BASF with respect to copper extraction as a function of pH and A/O ratio, and behavior of the impurities. At a pH below 0.5, the copper extraction increased quickly with increasing pH while at a pH above 0.5, it increased only slightly with pH. The copper extraction in organic solution was virtually not affected by the impurities. The iron extraction in organic solution increased with decreasing A/O ratio from 2:1 to 1:8 as the copper extraction decreased. Conversely, the Cu/Fe ratio in organic solution increased as copper extraction increased. The extractions of silver and lead were 1 mg/L or lower under all conditions tested. The other impurities (Zn, Ni, Cd, Cr, Hg, As and Sb) were virtually not loaded into the organic solution. The optimum copper solvent extraction conditions in chloride solution were proposed.