Synergism in gold–cyanide extraction with Primene JMT–Cyanex 925 mixed extractant system

• Published in: Hydrometallurgy Vol. 49; no. 3; pp. 309 - 322
• Main Authors: Martı́n, M.I., Alguacil, F.J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 1998; Elsevier
• Subjects: Applied sciences; Cyanide solutions; Exact sciences and technology; Gold; Hydrometallurgy; Metals. Metallurgy; Production of metals; Production of non ferrous metals. Process materials; Synergic extraction; Synergic extraction; Gold; Cyanide solutions; Amine; Xylene; Cyanides; Extraction; Selectivity; Experimental study; Synergism; Hydrometallurgy; Gold I
• ISSN: 0304-386X; 1879-1158
• DOI: 10.1016/S0304-386X(98)00042-5

The synergic extraction of gold (I) from cyanide solutions has been studied using a mixture of Primene JMT (primary amine=RNH 2) and Cyanex 925 (bis(2,4,4,trimethylpentylactyPhosphine oxide=R 3PO) in xylene. The variables that could affect the extraction system were investigated: equilibration time, temperature, aqueous pH, extractant mixture concentration, metal concentration and organic phase diluent. The selectivity of the system with respect to the extraction of different metal–cyano complexes was also evaluated. The gold (I) extraction reaction is discussed on the basis of the experimental results and numerical treatment of the experimental data. The species formed in the organic phase have the probable stoichiometry H +Au(CN) 2 −RNH 2(R 3PO) n , n being 1 (log K ext=10.27 max 10.55) or 3 (log K ext=12.80±0.13). Stripping of gold from loaded organic solutions was also studied using low ionic strength alkaline solutions at different experimental conditions.