Chemistry - Nuclear and Radiochemistry (C-NR), Los Alamos National Laboratory, Mail Stop J-514, Los Alamos NM 87545, USA.
Materials Synthesis and Integrated Devices (MPA-11), Los Alamos National Laboratory, Mail Stop J-514, Los Alamos NM 87545, USA.
J Chromatogr A. 2024 Aug 16;1729:465033. doi: 10.1016/j.chroma.2024.465033. Epub 2024 May 27.
Efficient rare earth element (REE) separations are becoming increasingly important to technologies ranging from renewable energy and high-performance magnets to applied radioisotope separations. These separations are made challenging by the extremely similar chemical and physical characteristics of the individual elements, which almost always occupy the 3+ oxidation state under ambient conditions. Herein, we discuss the development of a novel REE separation aimed at obtaining purified samples of neodymium (Nd) on a multi-milligram scale using high-speed counter-current chromatography (HSCCC). The method takes advantage of the subtle differences in ionic radii between neighboring REEs to tune elution rates in dilute acid through implementation of the di-(2-ethylhexyl)phosphoric acid (HDEHP)-infused stationary phase (SP) of the column. A La/Ce/Nd/Sm separation was demonstrated at a significantly higher metal loading than previously accomplished by HSCCC (15 mg, R > 0.85), while the Pr/Nd separation was achieved at lower metal loadings (0.3 mg, R = 0.75 - 0.83). The challenges associated with scaling REE separations via HSCCC are presented and discussed within.
高效的稀土元素（REE）分离对于从可再生能源和高性能磁铁到放射性同位素应用分离等技术变得越来越重要。这些分离由于各个元素极其相似的化学和物理特性而变得具有挑战性，这些元素在环境条件下几乎总是处于+3 氧化态。在此，我们讨论了一种新型 REE 分离方法的发展，该方法旨在使用高速逆流色谱法（HSCCC）在多毫克规模上获得纯钕（Nd）样品。该方法利用相邻 REE 之间离子半径的细微差异，通过在柱中实施二（2-乙基己基）磷酸（HDEHP）注入固定相（SP），在稀酸中调节洗脱速率。与以前通过 HSCCC 实现的相比（15 毫克，R > 0.85），La/Ce/Nd/Sm 分离在更高的金属负载下得到了证明，而 Pr/Nd 分离则在较低的金属负载下实现（0.3 毫克，R = 0.75-0.83）。讨论了通过 HSCCC 进行 REE 分离时所面临的挑战。
