Determination and distribution of gold in Greek bauxites of the Parnassos-Ghiona area by gamma-spectroscopy after ion exchange separation

For the determination of gold in Greek bauxites from the Parnassos-Ghiona area, an analytical technique was used based on the selective adsorption of gold on SRAFION NMRR chelating anion exchanger resin, after leaching the bauxites with aqua regia in a teflon-autoclave at 120 deg C, and the determination of the retained gold directly on the resin by instrumental neutron activation analysis (INAA), using the 411.8 keV line of the 198Au isotope. The procedure allowed to determine Au in concentrations down to ng/g. The obtained data were used to examine the distribution of Au in the profiles of a group of different bauxites from the upper or the called third bauxitic horizon of the Parnassos-Ghiona area in Greece. Especially in the basement of some bauxite deposits unexpected high concentrations of Au up to 2 μg/g have been found. Furthermore, the correlation of Au with other trace elements, found in the bauxitic samples, was investigated. (author)