EXTRACTION SEPARATION OF TERVALENT AMERICIUM AND LANTHANIDES IN THE PRESENCE OF SOME SOFT AND HARD DONORS AND DICARBOLLIDE

Some combinations of extractants involving dicarbollide as one compone nt for the separation of Am/Ln were studied. Extraction by TOPO is not influenced to a great extent by the presence of dicarbollide, and TPT Z in the presence of dicarbollide is ineffective for the extraction fr om 0.1 M HNO3. General aspects of the selectivity of lanthanides and o f Am/Ln separation in the presence of various reagents are discussed w ith emphasis on the difficulties of the separation of Am from light la nthanides. A new extraction procedure by dicarbollide in the presence of an excess of o-phenanthroline over the mineral acid is proposed. Th is led to the highest separation factors D(Am)/D(Eu) (20-34) from 0.1 M HNO3. The behavior of other lanthanides is similar to that of Eu, wi th a maximum distribution ratio for Nd (D(Nd)/D(Eu) = 2).