Solvent extraction of Au(I) from auro-cyanide solution with cetyltrimethylammonium bromide/tri-n-butyl phosphate system using column-shaped extraction equipment

Solvent extraction of Au(I) from alkaline cyanide solution containing several milligram per liter of gold was investigated with column-shaped extraction equipment using tri-n-butylphosphate (TBP) as extractant with addition of quaternary ammonium salt, cetyltrimethylammonium bromide (CTAB), directly into the aurous aqueous phase in advance. The influences of the volume of TBP and the NaCl concentration in the aurous aqueous phase on Au(I) extraction were investigated. The experimental results for treating 50 L of synthetic auro-cyanide solution containing 10 mg/L Au(I) and for treating real auro-cyanide leaching liquor by CTAB/TBP system were reported. The results obtained establish that the column-shaped extraction equipment was suitable for extracting Au(I) from low content auro- cyanide solution at high aqueous/organic phase ratio, and that more than 97% of gold(I) could be extracted while the Au(I) concentration in the raffinate was less than 0.3 mg/L. In addition, the stripping of Au(I) from the loaded organic phase and the recycle of the organic phase were also discussed.