Extraction of REE(III) with Mixtures of Picrolonic Acid and Bis-Carbamoylmethylphosphine Oxides

It was found that the extraction of REE(III) from weakly acidic chloride solutions into an organic phase containing bis-carbamoylmethylphosphine oxides increases significantly in the presence of picrolonic acid. The stoichiometry of the extracted complexes was determined, the effect of the aqueous phase composition, the nature of the organic solvent and the structure of bis-CMPO on the efficiency of metal ion extraction into the organic phase was considered. The use of picrolonic acid as a chelating component of the extraction mixture leads to a significantly greater increase in the extraction of REE(III) compared to 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone.