ELUTION AND ELECTROWINNING OF GOLD FROM GOLD-SELECTIVE STRONG-BASE RESINS

The recovery of gold was investigated using the new gold-selective resin, Minix, which was developed by Mintek. The most suitable elution technique for this resin was found to be an acidic thiourea eluant. The gold-selective adsorption characteristics of Minix, particularly its high selectivity against cobalt and iron cyanides, make it possible to use the advantages of the thiourea method (fast kinetics and circuit simplicity) without fear of poisoning the resin, as is the case with ordinary commercial resins. Electrowinning is compatible with the elution technique and provides a simple and effective method of recovering the gold from the eluate. The composition of the eluate does not affect the electrowinning efficiency much and it is therefore possible to operate both the elution and the electrowinning at their optimum efficiency. The feasibility of elution with simultaneous electrowinning was demonstrated in the laboratory. Complete elution and gold recovery were achieved in less than 5 h, with an average current efficiency of about 50%.