Solvent extraction of gold from polysulfide solution

The extraction of Au(I) from a polysulfide solution with TBP, amine alkyl extractants and their mixture was studied. The results show that Au(I) could be extracted with TBP or amine alkyl extractants, under the same condition, the extraction capacity of primary alkyl amine is better than that of tertiary alkyl amines. A mixture of N1923-TBP showed a synergistic effect. Separation of gold and copper from the polysulfide solution was readily achieved using 0.5 mol/L N1923–0.5 mol/L TBP/n-octane as the organic phase at pH < 8 or pH > 11 and the extraction rate of gold is very high.