基于碳酸盐环境的甲基三辛基碳酸铵萃取铀的分配比模型  

Distribution ratio model for extraction of uranium with methyltrioctylammonium carbonate based on carbonate system

作　　者：方豪凡 何明键 矫彩山[1] 张萌 王靖阳 FANG Haofan;HE Mingjian;JIAO Caishan;ZHANG Meng;WANG Jingyang(College of Nuclear Science and Technology,Harbin Engineering University,Harbin 150001,China)

机构地区：[1]哈尔滨工程大学核科学与技术学院,黑龙江哈尔滨150001

出　　处：《哈尔滨工程大学学报》2023年第12期2157-2162,共6页Journal of Harbin Engineering University

基　　金：国家自然科学基金项目(U196720065);黑龙江省核动力装置性能与设备重点实验室开放基金项目(HLJS202209).

摘　　要：为了解决基于碳酸盐体系的碱性乏燃料后处理流程,即CARBEX流程中萃取流程工艺设计困难的问题,本文建立了甲基三辛基碳酸铵萃取铀的分配比模型。主要考虑了水相碳酸盐浓度、水相铀浓度、萃取剂浓度和相比4个因素对铀的分配比影响,基于甲基三辛基碳酸铵在碳酸盐环境中萃取UO_(2)(O_(2))(CO_(3))_(4)^(-2)的萃取平衡方程式,采用分离变量的方法进行分段拟合,建立了铀的分配比模型。研究表明:与实验值对比,模型的相对误差在±10%以内。但是存在部分数据偏差过大,通过分析表明当有机相中铀浓度达到未萃取时萃取剂浓度的1/2以前,该模型适用;当超过1/2时,铀在有机相中发生化学形态的转变,因此模型不再适用。该研究是首次建立甲基三辛基碳酸铵的萃取铀的分配比数学模型,为后续碳酸盐体系的碱性乏燃料后处理流程工业化应用提供了一定的基础。In this study,a distribution ratio model for extraction of uranium by methyltrioctylammonium carbonate was established to address the issue of difficult process design in the extraction process of alkaline spent nuclear fuel reprocessing based on carbonate system,namely the CARBEX process.The effects of carbonate and uranium con-centrations in the aqueous phase,extractant concentration,and phase volume ratio were mainly investigated.Based on the extraction equilibrium equation of UO_(2)(O_(2))(CO_(3))_(4)^(-2)extracted by methyltrioctylammonium carbonate in a carbonate system,a distribution ratio model of uranium was established by segmental fitting using the method of separating variables.The results revealed that compared with the experimental value,the relative error of the model is within±10%.However,some data deviations are too large.The analysis shows that the model is appropriate when the uranium concentration in the organic phase reaches half of the extractant concentration before extraction.However,when the concentration exceeds half,the chemical form of uranium will change in the organic phase,and the model will no longer be applicable.

关 键 词：乏燃料后处理 碳酸盐体系 萃取分离 甲基三辛基碳酸铵 过氧碳酸铀酰 分配比模型 变量分离 分段函数 

分 类 号：TL241.1[核科学技术—核燃料循环与材料]