ABSTRACT

Bifunctional amidophosphonate derivatives, already known as efficient ligands in uranium extraction from phosphoric media, have been evaluated and compared to the conventional tri-n-butyl phosphate (TBP) for uranium extraction from nitrate medium. The efficiency of U extraction and its selectivity towards competing elements such as Th, Zr, Mo, Fe, and V was evaluated with various ligand structures. It was found that extractant molecules containing a monosaponified phosphonate moiety instead of phosphonate moieties are less effective and selective. Furthermore, it was observed that the alkylation of the methylene bridge linking the two functional groups prevents the formation of precipitates during the uranium loading. Effects of acidity as well as ligand concentration were also investigated in order to estimate the loading capacity of the molecules. More detailed stoichiometry and transfer energy were further determined by the slope analysis method and a thermodynamic study. The possible uranium recovery from the organic phase has moreover been demonstrated thanks to stripping steps at low nitric acid concentration.

摘要

已评估了双功能酰胺基膦酸酯衍生物（已被公认为从磷介质中提取铀的有效配体），并将其与从硝酸盐介质中提取铀的常规磷酸三正丁酯（TBP）进行了比较。使用各种配体结构评估了U提取的效率及其对竞争元素（如Th，Zr，Mo，Fe和V）的选择性。发现含有单皂化膦酸酯部分而不是膦酸酯部分的萃取剂分子不太有效和选择性。此外，观察到连接两个官能团的亚甲基桥的烷基化阻止了铀加载期间沉淀的形成。还研究了酸度和配体浓度的影响，以估计分子的负载能力。通过斜率分析法和热力学研究进一步确定了更详细的化学计量和传递能。此外，由于在低硝酸浓度下的汽提步骤，已经证明了从有机相中回收铀的可能性。