pH电位滴定法测定Zr(Ⅳ)-羟基脲配合物表观稳定常数  

Apparent Stability Constant of Zr(Ⅳ)-Hydroxyurea Complex With pH Potentiometric Titration

作　　者：杨雅雅 杨舒茗 李明明 刘晓娟 聂江 兰天[1] 肖松涛[1] 欧阳应根[1] YANG Ya-ya;YANG Shu-ming;LI Ming-ming;LIU Xiao-juan;NIE Jiang;LAN Tian;XIAO Song-tao;OUYANG Ying-gen(China Institute of Atomic Energy,P.O.Box 275(26),Beijing 102413,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

出　　处：《核化学与放射化学》2022年第2期214-220,共7页Journal of Nuclear and Radiochemistry

基　　金：国家自然科学基金资助项目(21790371)。

摘　　要：羟基脲(HU)在PUREX流程可作为还原剂和配位剂,其与乏燃料溶解液中重要裂片元素Zr(Ⅳ)的配位作用可提高PUREX流程对Zr的净化水平。本工作对硝酸体系中Zr(Ⅳ)与HU的配位作用进行了初步研究。通过等摩尔连续变化法(又称Job’s法)得到0.3 mol/L HNO_(3)下,Zr(Ⅳ)和HU的配位摩尔比为1∶8,结合半整数法算出Zr(Ⅳ)-HU的表观稳定常数为lg K_(1)≈1.59、lg K_(2)≈1.75、lg K_(3)≈1.88、lg K_(4)≈1.98、lg K_(5)≈2.09、lg K_(6)≈2.27、lg K_(7)≈2.51、lg K_(8)≈3.01。1.0 mol/L HNO_(3)下,Zr(Ⅳ)和HU配位摩尔比为1∶4,表观稳定常数为lg K_(1)≈2.33、lg K_(2)≈2.51、lg K_(3)≈2.78、lg K_(4)≈3.31。3.0 mol/L HNO_(3)下,Zr(Ⅳ)和HU配位摩尔比为1∶2,表观稳定常数为lg K_(1)≈2.69、lg K_(2)≈2.79。Hydroxyurea(HU)is a reducing and complexing agent that can be used in the PUREX process.Zr is an important fission product in the spent fuel and main element of concern in the nuclear fuel reprocessing.The decontamination of zirconium in the route of plutonium and uranium can be lowered by the complexation of hydroxyurea in the PUREX process.The complexation of Zr(Ⅳ)with hydroxyurea in the nitric acid system was investigated in this work.Under the condition of 0.3 mol/L HNO_(3),the complex ratio of Zr(Ⅳ)with HU is 1∶8 obtained by Job’s method.Combining with the half-integer method,the apparent stability constants of Zr(Ⅳ)with hydroxyurea are calculated as following:lg K_(1)≈1.59,lg K_(2)≈1.75,lg K_(3)≈1.88,lg K_(4)≈1.98,lg K_(5)≈2.09,lg K_(6)≈2.27,lg K_(7)≈2.51,lg K_(8)≈3.01.Under 1.0 mol/L HNO_(3),the complex ratio of Zr(Ⅳ)with hydroxyurea is 1∶4,and the apparent stability constants of Zr(Ⅳ)with hydroxyurea are lg K_(1)≈2.33,lg K_(2)≈2.51,lg K_(3)≈2.78,lg K_(4)≈3.31.Under 3.0 mol/L HNO_(3),the complex ratio of Zr(Ⅳ)with hydroxyurea is 1∶2,and the apparent stability constants of Zr(Ⅳ)with hydroxyurea are lg K_(1)≈2.69 and lg K_(2)≈2.79.

关 键 词：HU Zr(Ⅳ) Job’s法 表观稳定常数 

分 类 号：TL241.1[核科学技术—核燃料循环与材料] O615.11[理学—无机化学]