Solvent extraction of Au(CN)2− and application to facilitated supported liquid membrane transport

Abstract

The solvent extraction of gold(I) from aurocyanide solutions by means of various reagents: amines (Primene JMT, Amberlite LA2, Alamine 336), solvation extractants (TBP, Cyanex 921, DMPL) and mixtures of both is reported. Different variables that could affect the systems were evaluated; on the basis of the numerical treatment of experimental data, the stoichiometries of the extracted species (generally represented by HAu(CN)2·R·Lq, R being the amine, L the solvation extractant and q depending either of the amine and/or the solvation reagent) are proposed. The permeation of Au(I) through a supported liquid membrane impregnated with various of the extractants has been investigated. High selectivity in the separation, through supported liquid membrane, of Au(I) against different metal–cyano complexes (Ag(CN)2−, Cu(CN)43−, Zn(CN)42−, Fe(CN)63−) is achieved.