Metal-Promoted Extraction Deprotonation of Bidentate Organophosphoric Reagents: Recovery of Uranium, Thorium, and Lanthanides

Abstract

The extraction capacities to f elements are studied in a series of bidentate organophosphoric reagents that contain deprotonatable phenol moieties. The dependence of metal [thorium(IV), lanthanum(III), neodymium(III), and holmium(III)] recovery as a function of nitric acid concentration is represented by curves with a maximum, typical of extraction by monodentate organophosphoric reagents. The uranium recovery as a function of acid concentration is presented by curves with a minimum, indicating a change in extraction mechanism from ion exchange to solvation. The quantum-chemical modeling of reagent molecules and their complexes with uranyl ion is carried out. The reagents are structurally similar to reagent V, whose structure was determined by single-crystal X-ray diffraction. The results can be used in the hydrometallurgy of f elements.