EXTRACTION CHEMISTRY OF URANYL-NITRATE AND NITRIC-ACID IN HIGH-CONCENTRATION SYSTEMS

HNO3 is extracted in significant quantities by uranyl nitrate solvates with different extractants: TBP (tributyl phosphate), TOPO (trioctyl phosphine oxide) and TDA (tetradecyl ammonium). The effect of diluent nature is not observed on extracting HNO3 and TBP saturated by uranium at equilibrium with its salt using the diluents (CCl4, C6H5Cl, C-12 H26, CHCl3) which are less polar than UO2 (NO3)2 (TBP)2. HNO3 occurs in organic phase as undissociated form and its state is similar to pure anhydrous HNO3. Solvates of TBP and TDA with uranyl nitrate dissolve HNO3 without displacement of uranium from organic phase.