Selective separation of gold from iron ore samples using ion exchange resin

Gold in iron ore samples is separated from iron (major matrix cation), antimony and vanadium using anion exchange resin in (0.2 M) HBr, potassium peroxodisulfate and acetone: water: nitric acid media. The exchangeable anion Cl- of the ion exchanger Dowex 1X 4 is replaced by Br- using (6 M) HBr solution. Certified reference material DGP-M1, spiked ferric magnetic oxide, gold radioactive tracer Au-198 and gold standard solutions are used to study the adsorption efficiency and the yield recovery of tetrabromoaurate AuBr4- from the resin. Ten eluents have been tried to elute gold from the column, and it has been found that a 10 ml potassium peroxodisulfate and 240 ml acetone: water: nitric acid [125:5:5] solution fulfills the objective. The set up of the separation procedure allows quantitative adsorption of gold by the resin, while the major matrix cation (Fe) and others (Cd, Ag, Cu, V, Sb, Ti) have been passed through the column with the feeding solution (0.2 M) HBr. The resin selectivity coefficient W of separating Au from Fe has been found to be K-Fe(Au) approximate to 6.4 x 10(11). The eluted Au is treated with K2S2O8 and H2O2 for spectrophotometric determination as rhodamine-B complex at 555.6 nm. The linearity, detection limit, precision, and accuracy of the determination method have been found to be up to 2.0 mug g(-1), 0.018 mug g(-1), 0.009 mug g(-1) and 3%, respectively. (C) 2003 Elsevier B.V. All rights reserved.