强碱性阴离子交换树脂吸附DPA-Pu(Ⅳ)/U(Ⅵ)配合物研究  

Study on Adsorption of DPA-Pu(Ⅳ)/U(Ⅵ)Complex on Strongly Basic Anion Exchange Resin

作　　者：郝轩 柳倩 张国果 朱礼洋[1] 周今 石秀高[2] 刁妍红 杨素亮[1] 陈勤[2] 田国新[1,3] HAO Xuan;LIU Qian;ZHANG Guoguo;ZHU Liyang;ZHOU Jin;SHI Xiugao;DIAO Yanhong;YANG Suliang;CHEN Qin;TIAN Guoxin(Department of Radiochemistry,China Institute of Atomic Energy,Beijing 102413,China;The 404 Company Limited,China National Nuclear Corporation,Jiayuguan 732850,China;Institute of Nuclear and New Energy Technology,Tsinghua University,Beijing 100084,China)

机构地区：[1]中国原子能科学研究院放射化学研究所,北京102413 [2]中核四〇四有限公司,甘肃嘉峪关732850 [3]清华大学核能与新能源技术研究院,北京100084

出　　处：《原子能科学技术》2022年第8期1616-1625,共10页Atomic Energy Science and Technology

摘　　要：2,6-吡啶二羧酸(DPA,以H_(2)C表示)是一种可用于乏燃料后处理Purex流程高保留钚废有机相中钚洗脱的洗脱剂。为将DPA洗脱液中的钚与铀分离并回收钚,本文通过静态吸附实验研究了DPA-Pu(Ⅳ)/U(Ⅵ)配合物在强碱性阴离子交换树脂DOWEX 1上的吸附性能,考察了DPA浓度、酸度、温度以及主要辐解产物对DOWEX 1吸附钚和铀的影响。培养了DPA与U(Ⅳ)/U(Ⅵ)配合物的单晶并测定了其结构,通过配合物晶体与吸附金属离子树脂光谱的对比确定了Pu(Ⅳ)(以U(Ⅳ)模拟代替)和U(Ⅵ)吸附在树脂上的配合物形态,通过变温吸附实验获得了相应吸附反应的热力学数据。吸附实验结果表明,DOWEX 1树脂能在低酸(0.1 mol/L HNO_(3))条件下同时吸附钚和铀,在高酸(8 mol/L HNO_(3))条件下只吸附钚不吸附铀。根据上述实验所得结果,提出低酸吸附铀/钚、高酸柱上转型除铀、低酸解吸回收钚的方案,并进行了实验验证。结果表明,采用所提出的回收钚的方案,钚的回收率达96%,对铀的去污因子约为2.8×10^(3)。2,6-dipicolinic acid(DPA,expressed as H_(2)C)is expected to strip plutonium from high plutonium-retention waste organic solvent in the Purex process for spent fuel reprocessing.In order to separate the plutonium and uranium in the DPA stripping solution and recover the plutonium,the static adsorption experiment was conducted to investigate the adsorption performance of DPA-Pu(Ⅳ)/U(Ⅵ)complex on the strongly basic anion exchange resin DOWEX 1.The influence of DPA concentration,acidity,temperature and the main radiolysis products on the adsorption of plutonium and uranium by DOWEX 1 resin was studied,and the single crystal of DPA-U(Ⅳ)/U(Ⅵ)complex was obtained.By comparing the spectrum of the complex crystal and that of resin adsorbing with metal ions,the complex species adsorbed on resin of Pu(Ⅳ)(instead by U(Ⅳ))and U(Ⅵ)were determined.The thermodynamic data of the adsorption reaction were obtained by temperature variation experiments.Adsorption experiment results show that DOWEX 1 resin can simultaneously adsorb plutonium and uranium under low acid conditions(0.1 mol/L HNO_(3)),and under high acid conditions(8 mol/L HNO_(3))only plutonium but not uranium.Based on the above results,a practical plutonium stripping process is proposed that is plutonium and uranium adsorption on column at low acid,complex species transformation on column at high acid for uranium removal,and plutonium desorption from column at low acid.The process was validated by experiment,in which the plutonium recovery rate is 96%,and the uranium decontamination factor is about 2.8×10^(3).

关 键 词：PUREX流程 废有机相 高保留钚 2 6-吡啶二羧酸 DOWEX 1树脂 吸附分离 

分 类 号：O615.1[理学—无机化学]