Solvent Extraction of Silver and Gold From Alkaline Cyanide Solution with LIX 7950

Abstract

The cyanidation process is still the dominant technique for gold ore treatment. In this study, the potential use of the guanidine extractant LIX 7950 for recovering silver and gold from alkaline cyanide solution was investigated. The results indicate that LIX 7950 can effectively and efficiently extract silver and gold from their cyanide solution. The extraction of silver and gold with the extractant is favorable at low pH. High cyanide to silver ratio tends to suppress silver loading while cyanide concentration exhibits insignificant effect on gold extraction. The extraction of the mixture solution of metal cyanide complexes with the extractant indicated an extraction sequence of Au >A g > Zn > Ni > Cu > Fe. The loaded silver and gold can be stripped off efficiently with moderate strong NaOH solutions at the presence of small amount of NaCN. The important findings in the research suggest that the extractant can be potentially used to recover silver and gold from alkaline cyanide leachate and the barren cyanide solution from the SX circuit can be recycled to the cyanidation process.