SEPARATION OF TRANSPLUTONIUM ELEMENTS AND LANTHANIDES BY LIQUID COUNTERCURRENT CHROMATOGRAPHY IN SYSTEMS CONSISTING OF AQUEOUS NITRIC-ACID AND NEUTRAL BIDENTATE ORGANOPHOSPHORUS COMPOUNDS

A study is made of group separation of transplutonium elements (TPEs) and lanthanides (Ln) in systems consisting of aqueous nitric acid, car bamoylphosphine oxides (CMPOs), and chloroform by liquid countercurren t chromatography (LCC). Separation is incomplete because of low interg roup separation factor (only 55-75% of the elements of each group do n ot contain impurities of elements of another group). The method of iso cratic separation of microamounts of TPEs and macroamounts of lanthani des in the 3 M HNO3-alpha-pyridylmethylbis[diphenylphosphine] dioxide- chloroform system is proposed. In this case, satisfactory separation i s reached: more than 99.5% of the Ln sum do not contain TPEs and more than 90% of TPEs do not contain lanthanides; 10% of TPEs contain 0.35% impurity of lanthanides.