EXTRACTION OF NOBLE-METALS BY SULFUR-CONTAINING REAGENTS AND SOLVENT IMPREGNATED RESINS

The extraction of AU(3+) and Ag+ by two thiourea-based extraction reag ents, nonylthiourea (NTH) and dodecylthiourea (DTH) as well as triisob utylphosphine sulfide (Cy, commercially known as Cyanex 471X(R)) from HCl and HNO3 are reported. The distribution data have been analyzed an d the complexes formed in the different systems have been determined. The extraction of AU(3+) and Ag+ by the reagents is very fast and the equilibrium is achieved in less than 3 minutes. The reagent NTH was fo und to have high selectivity for gold and silver against copper and ir on from hydrochloric acid solutions. The extraction of platinum group metals (Pt, Pd, and Rh) by these reagents is also reported. Solvent im pregnated resins(SLR) have been prepared from NTH, DTH and Cy and macr oporous polymers. The extraction of gold(III) from HCl solutions by th ese resins was studied.