Gold recovery by galvanic stripping of an anionic organic extractant

The galvanic stripping technique for metal recovery uses commercial organic extractants containing a metal to be recovered. The organic phase is place d in contact with a solid metal reducer that allows electrochemical reactio ns to occur. One product of these reactions is a metal layer deposited on t he surface of the reducer consisting of reduced species desorbed from the o rganic phase. Another product is metal ions from the reducer adsorbed onto the organic phase. This work presents results for gold recovery by galvanic stripping of stron g-base anionic extractants of a quaternary amine salt, ALIQUAT336 (R), in x ylene using solid zinc as the metal reducer. The parameters studied were co ntact time for the organic phase containing gold and the samples of the red ucing zinc metal, temperature of the system, gold concentration in the orga nic phase and type of stirring used in the galvanic stripping system. Exper iments showed results higher than 28% of gold recoery and an adherent film of gold on the zinc surface, The Arrhenius plot for gold recovery from the organic extractant suggests a change in the rate- controlling step from mix ed control to diffusion control with increasing temperature in the range of 20 to 50 degreesC.