Abstract
The synergistic extraction of rare earth elements (III) has been investigated by a mixture of 2-thenoyltrifluoroacetone (HA) and 3,5-di (2-pyridyl) pyrazole (dpp) as a neutral ligand (S). Large synergistic enhancement was produced owing to the formation of the adduct complexes such as MA_ЗS. Extraction constants of rare earth elements with Htta in the absence and the presence of the neutral ligand were evaluated. The adduct formation constants have a similar value for La to Er and slightly decrease for heavier lanthanoids.
