核燃料循环中镅的氧化分离研究进展

镅离子在溶液中主要以三价形式(Am(III))存在,因其离子半径与三价镧系离子Ln(III)接近,化学特性相似,使得Am(III)与Ln(III)的有效分离被认为是核燃料循环领域最具挑战性的课题之一。利用镅的多价态特性,采用不同氧化方法可将Am(III)氧化成高价态的AmO_2~+和AmO_2~(2+)形式,再通过溶剂萃取、沉淀等方法进行分离,是实现Am与Ln分离的一种新思路。本文综述了不同氧化方法对水溶液环境中Am(III)的氧化分离研究进展,描述了相关机理,指出了不同氧化方法的优劣并展望了未来发展趋势,以期为发展新型镧系与锕系元素分离技术提供参考。

Progress in the Oxidation Separation of Americium in Nuclear Fuel Cycles

Americium mainly exists as trivalent Am(III) in aqueous solutions. Due to the similarity in ionic radius and chemical properties of Am(III) and trivalent lanthanides (Ln(III)), the separation of Am(III) from Ln(III) is regarded as one of the most challenging tasks in nuclear fuel cycles. Am(III) can be oxidized to higher oxidation states such as AmO₂⁺ and AmO₂²⁺ through different oxidation methods and then it could be separated from Ln(III) by using well-developed solvent extraction or precipitation methods, providing a new route for the separation of Am from Ln. In this paper, the progress on the oxidation separation of Am(III) in nuclear fuel cycles have been reviewed, the oxidation principles and relevant mechanisms were described, the advantages and disadvantages of various methods were compared, and the future trends for the oxidation separation of Am(III) were also discussed. It hopes to provide a guidance for developing novel techniques for the separation of actinides and lanthanides.