Kinetics of Americium(III) Extraction and Back Extraction with BTP
Kinetics of Americium(III) Extraction and Back Extraction with BTP
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DOI：
10.1080/07366290600948582
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发表时间：
2006-12
影响因子：
2
通讯作者：
M. Weigl;A. Geist;U. Müllich;K. Gompper
中科院分区：
文献类型：
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作者：
M. Weigl;A. Geist;U. Müllich;K. Gompper
摘要2，6-二（5，6-二丙基-1，2，4-三嗪-3-基）吡啶（BTP）从硝酸溶液中萃取三价锕系元素，具有比镧系元素高的分离因子。在恒界面搅拌槽中研究了该萃取体系萃取和反萃取镅（III）的动力学。镅（III）的提取率被认为是独立的搅拌速度。这意味着传质速率受到缓慢的化学络合反应（“化学状态”）的限制。镅（III）的萃取率被发现与BTP浓度线性增加。硝酸浓度有很强的影响率的镅（III）的提取，由于其对游离萃取剂浓度的影响。硝酸铵的加入不影响镅（III）的提取率。通过研究界面面积对镅（III）萃取率的影响，确定界面为化学反应的位点。镅（III）的反萃取率随搅拌速度线性增加，表明反萃取受扩散限制。萃取率和反萃取率可以通过基于镅（III）和硝酸共萃取的平衡数据的简单模型来计算。
Abstract 2,6‐Di(5,6‐dipropyl‐1,2,4‐triazin‐3‐yl)pyridine (BTP) extracts trivalent actinides from nitric acid with high separation factors over the lanthanides. The kinetics of americium(III) extraction and back extraction of this extraction system was studied in a constant‐interface stirred cell. The americium(III) extraction rate was found to be independent of the stirring speed. This means that the rate of mass transfer is limited by a slow chemical complexation reaction (“chemical regime”). The americium(III) extraction rate was found to increase linearly with BTP concentration. Nitric acid concentration had a strong influence on the rate of the americium(III) extraction, due to its influence on the free extractant concentration. The addition of ammonium nitrate did not affect the rate of americium(III) extraction. By investigating the influence of the interfacial area on the americium(III) extraction rate, the interface was identified as the site of the chemical reaction. The americium(III) back extraction rate increased linearly with the stirring speed, indicating that the back extraction is limited by diffusion. The extraction and the back extraction rates could be calculated by a simple model based on equilibrium data for the co‐extraction of americium(III) and nitric acid.