The paper presents the results of studies of the physicochemical processes of the extraction and nitric acid purification of uranium salts obtained by the method of precipitation of ammonium uranyl carbonate (AUC) from ore solutions of leaching of uranium and polymetallic ores with their subsequent dissolution in nitric acid. It is shown that the process of extraction on a mixture of tributyl phosphate (TBP) in kerosene makes it possible to obtain high-purity uranium oxide. For the selective extraction of impurities, the process of uranium extraction from the nitric acid medium was carried out with a mixture of TBP and di(2-ethylhexyl) phosphoric acid (DEHPA) in kerosene. The first uranium concentration 40…50 g/L simulated the process of uranium desorption, the second ≤ 100 g/L simulated the process of dissolution of uranium oxide. The study of the uranium extraction made it possible to determine the required number of extraction stages to achieve the minimum uranium content in the raffinate and the maximum extractant capacity, which ensured the specified coefficients of uranium purification from metal impurities (V, Mo, etc.). After extraction, the nitric acid raffinate served as a raw material for the production of a mineral fertilizer – sodium nitrate.

The article presents the results of industrial testing of processes for obtaining high-purity uranium compounds, including extraction, concentration, and purification of uranium from a mixture of nitric and phosphoric acids, solid-phase stripping, and reduction of U(VI) to U(IV). It is shown that the combination of three different extraction lines for the concentration and purification of uranium from accompanying valuable elements and radioactive isotopes makes it possible to obtain a natural uranium concentrate with a low content of impurities, which determine the economics of uranium hexafluoride production. The processes of drying and roasting of crystals of ammonium uranyl tricarbonate after solid-phase re-extraction in an atmosphere of reducing gases of ammonia and hydrogen make it possible to obtain uranium dioxide suitable for fluorination to obtain tetra and uranium hexafluoride.