Assessment of the Precious Metals Content in Carrier Minerals by the Neutron Activation Analysis with a Radioactive Source

The article discusses the possibility of using the INAA method based on a 252Cf radionuclide neutron source for determining the content of Sc, In and Au in various minerals. The method was tested on samples of cassiterite, wolframite, hubnerite, chalcopyrite, and arsenopyrite, as well as galena and sphalerite (both in a monomineral samples and in their mixtures). Sc was found in the samples at concentrations ranging from 0.8 to 29 ppm in cassiterite and 21.9 to 469 ppm in wolframite (in the latter, it is 1.4 to 30 times higher than the Clarke value). Average In content (g/t): in cassiterite—17 (90 times exceeding Clarke value), in hubnerite—9 (47 times), in chalcopyrite—988 (5200 times), and in mixed sulfides—49.3 (260 times). Results for Au (g/t): in cassiterite—from 0.14 to 66.9 (exceeding Clarke value 32 and 1520 times), in hubnerite—0.28-3.82 (Clark excess 64‒870 times), and in mixed sulfides (arsenopyrite, galena, sphalerite)—0.53-4.55 (120-1034 times).