STUDY ON THE EXTRACTION OF AMERICIUM AND SOME LANTHANIDES BY CYANEX 301 AND CYANEX 302Liu Demin Shao Yun Liu Xiangfeng Yang Yusheng(Northwestern Institute of Nuclear Technology,P.O.Box 69(17),Xi'an 710024)ABSTRACTThe solvent extraction of Am3＋、La3＋、Eu3＋ and Tm3＋ by Cyanex 301 (bis(2,4,4trimethylpentyl)dithiophosphinic acid) and Cyanex 302 (bis(2,4,4trimethylpentyl)monothiophosphinic acid) in cyclohexane from natrate aqueous solution has been investigated.The results show that the extraction behaviors of trace amount of Am3＋ and Eu3＋ by Cyanex 301 or Cyanex 302 are very similar.However,in the presence of macro amount of La(NO3)3,the high selectivity towards Am3＋ is rather apparent.The separation factor for Am3＋ and Eu3＋ is as high as 200,and the order of distribution coefficient for rare earth elements is:DTm>DEu>DLa.Key words Americium Lanthanides Cyanex 301 Cyanex 302 Extraction