In the framework of the R&D program conducted in France on partitioning and transmutation of minor actinides, a solvent extraction process was developed for separating americium from a PUREX raffinate arising from the dissolution of spent nuclear fuels in nitric acid. The so-called EXAm process uses a mixture of a malonamide (DMDOHEMA, N,N’-dimethyl-N,N’-dioctyl-hexyloxyethyl-malonamide) and HDEHP (di-2-ethylhexylphosphoric acid) in organic phase in combination with a water-soluble complexing agent TEDGA (N,N,N’,N’-tetraethyldiglycolamide) in aqueous phase to enhance Am/Cm separation. Am/Ln separation is then obtained by selective Am stripping with polyaminocarboxylic acids (HEDTA or DTPA) buffered by citric or malonic acid at low acidity. Started in 2008, an important R&D program was conducted at CEA to optimize and model the process. The feasibility of the direct recovery of Am from a genuine PUREX raffinate by solvent extraction was demonstrated in 2010 and reported, for the first time in the literature. R&D was then conducted to adapt the process for a future scale-up and for application from concentrated PUREX raffinates. The results of the final EXAm process performed on a highly active PUREX concentrate are presented after a summary of 10 years of R&D on this process development.

在法国进行的次act系元素的分配和转化研究计划的框架内，开发了一种溶剂萃取工艺，用于将乏核燃料溶解在硝酸中而从PUREX提余液中分离a。所谓的EXAm工艺使用有机相中丙二酰胺（DMDOHEMA，N，N'-二甲基-N，N'-二辛基-己氧基氧基乙基-丙二酰胺）和HDEHP（二-2-乙基己基磷酸）的混合物水溶性络合剂TEDGA（N，N，N'，N'-四乙基二甘醇酰胺），以增强Am / Cm分离。然后通过用低酸度的柠檬酸或丙二酸缓冲的聚氨基羧酸（HEDTA或DTPA）进行选择性Am剥离，从而获得Am / Ln分离。从2008年开始，CEA进行了一项重要的研发计划，以优化和建模流程。通过溶剂萃取从纯正纯PUREX萃余液中直接回收Am的可行性已在2010年得到证实，并首次在文献中报道。然后进行了研发，以使该过程适应将来的规模化发展，并从浓缩的PUREX残液中应用。在对该工艺开发进行了10年的研发总结之后，介绍了在高活性PUREX精矿上进行的最终EXAm工艺的结果。