Journal of Isotopes ›› 2022, Vol. 35 ›› Issue (5): 415-423.DOI: 10.7538/tws.2021.youxian.107

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Liquid-liquid Extraction of U(Ⅵ) and Pu(Ⅳ) with 2,2′-((4-Ethoxy-1,2-phenylene) bis (oxy)) bis (N,N-bis(2-ethylhexyl)acetamide)

DING Qixiu;GE Xiao;ZHU Haowei;CHEN Qi;LYU Hongbin;ZHENG Weifang;YAN Taihong   

  1. Department of Radiochemistry, China Institute of Atomic Energy, Beijing 102413, China
  • Online:2022-10-20 Published:2022-10-20

2,2′-((4-乙氧基-1,2-亚苯基)双(氧基))双(N,N-双(2-乙基己基)乙酰胺)对U(Ⅵ)、Pu(Ⅳ)的萃取行为研究

丁琪秀;葛晓;朱浩玮;陈琦;吕洪彬;郑卫芳;晏太红   

  1. 中国原子能科学研究院 放射化学研究所,北京102413

Abstract: To develop a highly selective extractant for Pu(Ⅳ), 2,2′-((4-ethoxy-1,2-phenylene)bis(oxy)) bis (N,N-bis(2-ethylhexyl)acetamide), short for 4-EthoxyBenzoDODA, has been evaluated as a novel extractant in n-dodecane diluent for the extraction of U(Ⅵ) and Pu(Ⅳ). The effect of contact time of two phases, HNO3 concentration and extractant concentration on the distribution ratios of U(Ⅵ) and Pu(Ⅳ) was investigated. Acid uptake studies suggested that 4-EthoxyBenzoDODA (KH=0.14) was less basic as compared to BenzoDODA (KH=0.44), making it more conducive to selectively extract Pu(Ⅳ) with stronger ionic potential. Extraction experiments showed that the maximum of SFPu/U, SFPu/Eu were 6.9, 223 respectively. Slope analysis indicated extraction of 1∶1 (ML) species with U(Ⅵ) and mixed 1∶1 (ML) and 1∶2 (ML2) species with Pu(Ⅳ) at 4.0 mol/L HNO3 98% of Pu in the loaded organic phase can be stripped to the aqueous phase using reductive stripping agent such as hydrazine nitrate and hydroxylamine nitrate. The results showed that the 4-EthoxyBenzoDODA exhibited good selectivity toward Pu.

Key words: uranium, plutonium, selective extractant, separation factor

摘要: 为开发Pu(Ⅳ)的高选择性萃取剂,实现废液中微量钚的回收,以正十二烷作为稀释剂,研究2,2′-((4-乙氧基-1,2-亚苯基)双(氧基))双(N,N-双(2-乙基己基)乙酰胺)(4-EthoxyBenzoDODA)对U(Ⅵ)、Pu(Ⅳ)的萃取行为,以及两相混合振荡时间、水相硝酸浓度和有机相萃取剂浓度对U(Ⅵ)、Pu(Ⅳ)萃取分配比的影响。硝酸的萃取实验结果表明,4-EthoxyBenzoDODA(KH=0.14)比BenzoDODA(KH=0.44)碱性弱,更有利于选择萃取离子势较强的Pu(Ⅳ)。对U(Ⅵ)、Pu(Ⅳ)的萃取实验表明,Pu(Ⅳ)对U(Ⅵ)的分离因子最高可达6.9,Pu(Ⅳ)对Eu(Ⅲ)的分离因子最高可达223。采用斜率法分析了4.0 mol/L HNO3浓度下U(Ⅵ)萃合物的组成,主要为UO2(NO3)2·L)、Pu(Ⅳ)(Pu(NO3)4·L和Pu(NO3)4·L2共存。使用硝酸肼或者硝酸羟胺等还原反萃剂,可以将负载有机相中98%的Pu反萃至水相中。结果表明,4-EthoxyBenzoDODA对Pu(Ⅳ)具有一定的选择性。

关键词: 铀, 钚, 选择性萃取剂, 分离因子