Separation of Gold, Palladium and Platinum in Chromite by Anion Exchange Chromatography for Inductively Coupled Plasma Atomic Emission Spectrometric Analysis

摘要

A study has been carried out on the separation of gold, iridium, palladium, rhodium, ruthenium and platinum in chromite samples and their quantitative determination using inductively coupled plasma atomic emission spectrometry (ICP-AES). The dissolution condition of the minerals by fusion with sodium peroxide was optimized and chromatographic elution behaviour of the rare metals was investigated by anion exchange chromatography. Spectral interference of chromium, a matrix of the minerals, was investigated on determination of gold. Chromium interfered on determination of gold at the concentration of 500 mg/L and higher. Gold plus trace amounts of iridium, palladium, rhodium and ruthenium, which must be preconcentrated before ICP-AES was separated by anion exchange chromatography after reducing Cr(サ) to Cr(ゲ) by H₂O₂. AuCl₄- retained on the resin column was selectively eluted with acetone- HNO₃-H₂O as an eluent. In addition, iridium, palladium, rhodium and ruthenium remaining on the resin column were eluted as a group with concentrated HCl. However, platinum was eluted with concentrated HNO₃. The recovery yield of gold with acetone-HNO₃-H₂O was 100.7 【2.0%, and the yields of palladium and platinum with concentrated HCl and HNO₃ were 96.1 【1.8% and 96.6 【1.3%, respectively. The contents of gold and platinum in a Mongolian chromite sample were 32.6 【 2.2 Ф/g and 1.6 【 0.14 Ф/g, respectively. Palladium was not detected.