EXTRACTION OF ACTINIDES AND LANTHANIDES BY ALKYLPHENOL SULFIDES

The extraction chemistry of Am and rare earths by S-containing alkylph enol derivatives in the presence of various complexants (K2CO3, K2C2O4 , NaC2H3O2) is studied by distribution measurements using C-13 NMR spe ctroscopy. In these systems, the elements are extracted well by p-tert -butylphenol disulfide (BPDS) and its oligomeric derivative octophor 1 0S at high pH values, i.e., under conditions where various hydroxo spe cies exist in the aqueous phase. In all probability, the extraction oc curs by stripping OH groups from the hydroxo ions and protons from the hydroxyl groups of the reagents. The changes in the C-13 MMR paramete rs of BPDS resulting from complexation with rare earths are consistent with the substitution of hydroxyl protons by metals to form a M-O bon d and additional coordination to the S donor. The experimental data su ggest that alkylphenol sulfides extract trivalent actinides and lantha nides from complexing solutions at high pH values as stable chelates.