MIXED-LIGAND CHELATE EXTRACTION OF TRIVALENT LANTHANIDES AND ACTINIDES WITH 1-PHENYL-3-METHYL-4-BENZOYL-PYRAZOLONE-5 AND DIHEXYL-N,N-DIETHYLCARBAMOYLMETHYL PHOSPHONATE

Mixed-ligand chelate extraction of trivalent lanthanides such as La, E u and Lu and a trivalent actinide, Am into xylene with mixtures of 1-p henyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP) and dihexyl-N,N-diethylc arbamoylmethylphosphonate (CMP) has been studied by tracer techniques. These trivalent metal ions are found to be extracted from 0.01 mol/dm (3) chloroacetate buffer solutions as M(PMBP)(3) . HPMBP type self add ucts with HPMBP alone and in the presence of CMP as M(PMBP)(3) . CMP ( where M = La, Eu, Lu and Am) into the organic phase. The equilibrium c onstants of the shove species are deduced by non-linear regression ana lysis. The synergistic constants of trivalent lanthanides do not incre ase monotonically with atomic number but have a maximum at Eu and that of Am was found to lie between that of La and Eu.