Nitric Acid Processing of Perovskite Concentrate under Atmospheric and Autoclave Conditions

The interaction of perovskite concentrate with nitric acid under atmospheric conditions and at an excess pressure was studied. High efficiency was achieved in the separation of components in the form of a solid phase (hydrated precipitate of titanium and rare metals) and a liquid phase containing calcium, rare-earth metals, and thorium. It was shown that the conditions of the acid treatment of the resulting precursors determine their structure and composition, which, in turn, determine the directions of their further processing to obtain final products. In particular, it was established that an increased pressure in the reaction zone causes rutilization of the hydrated precipitate, and therefore its further processing to produce titanium dioxide and rare metals should be carried out by chlorination.