Instrumental neutron activation analysis of monomineral fractions of sulfide minerals and quartzes

A method has been worked out of multi-elemental instrumental neutron-activation analysis INAA of small weights some mg of monomineral fractions of sulfide minerals pyrites, galenites, chalcopyrites, arsenopyrites, bornites, chalcosines and quartzes. The samples were irradiated in a nuclear reactor under a flux of 1.3·10¹³ n·cm⁻²·s⁻¹. For measuring the gamma radiation of the exposed samples Ge(Li) gamma-spectrometers with semiconductor detectors were used. Determined in sulfide monofractions were the elements: Co, Sc, Ag, Se, Sb, Cr, Fe, Zr; rare-earth elements: Ce, Sm, Eu and others at content levels of 10⁻¹−10⁻⁴%. In quartzes they were: Mn, Na, Sb, Cr, Sc, Fe, Co at content levels of 10⁻⁵−10⁻⁷% and Au to n×10⁻⁹%. A special method has been worked out for the determination of In in sulfides with the irradiation of samples in a cadmium screen. An example is cited of using the method for studying some peculiar features of the genetics of copper pyrite deposits. The data on the distribution of admixture elements in sulfide monofractions produced in this work made it possible to conclude that the oreformation in the deposits has a stage-by-stage character.