Determination of scandium in ash and slag wastes and products of their processing by instrumental neutron activation analysis

Abstract

Abstract Ash and slag waste accumulated throughout the world in appreciable amounts are, in essence, man-made deposits and are of interest as a potential source of critical elements, in particular Sc, as well as raw materials for obtaining construction materials. Coals from Siberia and the Far East are used as fuel at thermal power plants (TPPs) in the Primorsky Territory of Russia. These coals are characterized by a high Sc content. The content of Sc in the ash and slag wastes from landfills of six TPPs in Primorsky Krai was determined by neutron activation analysis with a Cf-252 radionuclide source. The Sc content ranged from 5.1 to 52.7 ppm. Average concentrations of Sc in ash and slag waste are 23.3 ppm. Verification of the INAA method was carried out by comparing with the ICP-MS data in reference materials (laterite and carbonatite scandium-containing ores). The possibility of using the Sc-46 isotope, produced by thermal neutron activation, as a radioactive tracer to assess the effectiveness of operations for Sc extraction and concentration is shown. Sc has been preconcentrated from the initial ash of the Primorsky thermal power plant by the precipitation method in the form of hydroxide, followed by separation from accompanying elements by dissolving the hydroxide in sodium hydroxide or hydrochloric acid. The possibility of concentrating Sc more than 4 times from the initial ash has been shown.