REDOX BEHAVIOUR OF NEPTUNIUM IN PUREX EXTRACTION PROCESSES

PUREX 萃取过程中镎的氧化还原行为

• 批准号: 03453166
• 负责人: INOUE Yasushi
• 金额: $ 4.16万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-03453166/
• 关键词: neptunium; nitrous acid; nitric acid; Purex process; solvent extraction; TBP; oxidation; kinetics

In order to clarify the distribution behavior of neptunium in the Purex extraction processes, the equilibrium and rate of the extraction of neptunium into 30% TBP-dodecane were examined as a function of nitrous acid (3-6 M) and nitrous acid (10^<-4>-10^<-2> M) concentrations. It was shown that the rapid equilibrium between nitric and nitrous acids controlls the redox potential of the aqueous phase, which in turn controlls the ratio of the concentrations of extractable Np(VI) to unextractable Np(V). The redox potential can be quantitatively described with using the activities of nitric acid, nitrous acid and water in nitric acid solutions:E/V = 0.951 + 0.058・log<@D7{HNO<@D23@>D2}<@D12@>D1(/){HNO<@D22@>D2}<@D11/2@>D1{H<@D22@>D2O}<@D11/2@>D1@>D7 By examining also the rate of the extraction of neptunium into TOPO-dodecane, the ratedetermining step was confirmed to be the oxidation of Np(V) to Np(VI) in the aqueous phase. The rate of the reaction was obtained to be:k/h = 5.44 x {HNO_3}^<1.02>{HNO_2}^<0.56>

为了弄清Nb在Purex萃取过程中的分布行为，研究了30%TBP-十二烷中Nb的萃取平衡和速率与亚硝酸(3-6M)和亚硝酸(10^&lt；-4&gt；-10^&lt；-2&gt；M)浓度的函数关系。结果表明，硝酸和亚硝酸之间的快速平衡控制了水相的氧化还原电位，进而控制了可提取的Np(VI)和不可提取的Np(V)的浓度之比。氧化还原电位可用硝酸、亚硝酸和水在硝酸溶液中的活度来定量描述：E/V=0.951+0.058・log&lt；@D7{HNO&lt；@D23@&gt；D2}&lt；@D12@&gt；D1(/){HNO&lt；@D22@&gt；D2}&lt；@D11/2@&gt；D1{H&lt；@D22@&gt；D2O}&lt；@D11/2@&gt；D1@&gt；D7还考察了拓扑十二烷萃取Ne的速率，确定了Np(V)在水相中氧化为Np(VI)的决定步骤。反应速率为：K/h=5.44x{HNO_3}^&lt；1.02&gt；

项目成果

井上 泰: "ピュレックス工程におけるネプツニウムの酸化還元挙動" 日本原子力学会 1991年秋の大会講演要旨集.

Yasushi Inoue：“Purex 过程中镎的氧化还原行为”日本原子能学会 1991 年秋季会议摘要。

井上 泰: "ピュレックス工程におけるネプツニウムの酸化還元挙動" 日本原子力学会1991年秋の大会講演要旨集. 674 (1991)

Yasushi Inoue：“Purex 过程中镎的氧化还原行为”日本原子能学会 1991 年秋季会议摘要 674 (1991)。

Y.Inoue,O. Tochiyama and Y.Nakamura: "Redox Behavior of Neptunium in Purex Extraction Process" 1991 Fall Meeting of the Atomic Energy Society of Japan. 674 (1991)

井上，O.