RADIOCHEMICAL PRECONCENTRATION OF NOBLE AND PLATINUM-GROUP METALS FORNUCLEAR ACTIVATION-ANALYSIS

A radiochemical methodology has been designed to preconcentrate traces of noble and platinum-group metals in aluminium oxide matrix for thei r charged particle activation analysis. In developing the procedure, t races of noble and platinum group metals present in some geological sa mples were preconcentrated in lead buttons through usual fire assay te chnique and were subjected to neutron activation at APSARA reactor, BA RC, Bombay. The activated samples containing the radioactive isotopes of gold, silver and platinum were dissolved in HNO3 and concerned elem ents were then separated and determined radiometrically, from lead nit rate solution by their extraction with Aliquot 336 (similar to 1%) at 0.1N HNO3. The elements taken up by the liquid extractant were then ex tracted back into concentrated HNO3 and were then coprecipitated with Al(OH)(3). The precipitate, Al(OH)(3) on heating at similar to 600 deg rees C was converted to Al2O3, a suitable solid matrix for charged par ticle activation analysis of the elements.