EXTRACTION OF ACTINIDES AND LANTHANIDES WITH DIPHENYLDIBUTYLCARBAMOYLMETHYLPHOSPHINE OXIDE IN THE ABSENCE OF A SOLVENT

摘要

It is established for the first time that solid diphenyl[dibutylcarbamoylmethyl]phosphine oxide (DPDBCMPO) forms liquid phases ("liquid reagent") non-miscible with acid solutions on contact with mineral acids. It is found that the compositions of liquid reagent correspond to DPDBCMPO HNO_3 nH_2O and 2DPDBCMPO HAn nH_2O, where HAn is HCIO_4 or HCI. The compositions of nitrate and perchloric complexes of liquid reagent with U(Ⅵ) and Nd(Ⅲ) are found. Extraction of a number of actinides in various oxidation states as well as extraction of some lanthanides by liquid reagent in the absence of organic solvent is studied. It is shown that in case of extraction by liquid reagent, distribution ratios increase in comparison with usual solvent extraction. It is established that the complex of the reagent with nitric acid has redox properties resulting in a change of valence states of some actinides in the process of extraction. The use of inert matrices containing DPDBCMPO is suggested for isolation and immobilization of actinide and rare-earth elements by vitrification.