Recovery of metals from chloride leach solutions of anode slimes by solvent extraction. Part II: Recovery of silver and copper with LIX 63 and Alamine 336

Abstract

In Part 1 of this paper, gold(III) and Sn(II) were recovered from the chloride leach solution of anode slimes by extraction with Cyanex 272 and stripping with (NH4)2S2O3 and NaOH solutions for gold(III) and Sn(II), sequentially. In this work, solvent extraction experiments were conducted to recover Ag(I) and Cu(II) from the Au(III) free raffinate containing Ni(II), Sn(II) and Zn(II) using two systems. In the first system, Cu(II) and Ag(I) were sequentially separated using LIX 63 and Alamine 336, respectively. Dilute HCl and NH4SCN were used as the stripping agents for Cu(II) and Ag(I), respectively. In the second system, Cyanex 301 co-extracted Ag(I), Cu(II) and Sn(II) from the Au(III) free raffinate. Aqua regia at different dilutions stripped these three metal ions from the loaded Cyanex 301. First, Cu(II) was selectively stripped from the loaded Cyanex 301 by employing ten times diluted aqua regia. Second, most of Ag(I) was selectively stripped over Sn(II) by five times diluted aqua regia. A process flowsheet for the separation and recovery of noble and base metals from the chloride leach solution of anode slime using extraction and stripping has been proposed.