Solvent extraction is the most widely used method for separation and purification of rare earth elements, and organic extractants such as di(2-ethylhexyl) phosphoric acid (P204) and di(1-methyl-heptyl) methyl phosphonate (P350) are most commonly used for industrial applications. However, the presence of impurity ions in the feed liquid during extraction can easily emulsify the extractant and affect the quality of rare earth products. Aluminum ion is the most common impurity ion in the feed liquid, and it is an important cause of emulsification of the extractant. In this study, the influence of aluminum ion was investigated on the extraction of light rare earth elements by the P204-P350 system in hydrochloric acid medium. The results show that Al³⁺ competes with light rare earths in the extraction process, reducing the overall extraction rate. In addition, the Al³⁺ stripping rate is low and there is continuous accumulation of Al³⁺ in the organic phase during the stripping process, affecting the extraction efficiency and even causing emulsification. The slope method and infrared detection were utilized to explore the formation of an extraction compound of Al³⁺ and the extractant P204-P350 that entered the organic phase as AlCl[(HA)₂]₂P350_(o).

中文翻译：

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杂质铝对P204-P350在氯化物溶液中萃取稀土元素（Nd，Pr，La）的影响及机理研究

溶剂萃取是分离和纯化稀土元素的最广泛使用的方法，有机萃取剂如磷酸二（2-乙基己基）酯（P204）和磷酸二（1-甲基庚基）甲酯（P350）用于工业应用。然而，萃取过程中进料液体中杂质离子的存在会轻易使萃取剂乳化并影响稀土产品的质量。铝离子是进料液体中最常见的杂质离子，并且是萃取剂乳化的重要原因。在这项研究中，研究了铝离子对P204-P350系统在盐酸介质中萃取轻稀土元素的影响。结果表明，Al ³⁺在提取过程中与轻稀土竞争，降低了总提取率。另外，Al ^3+的汽提速率低，并且在汽提过程中有机相中Al ³⁺不断累积，影响萃取效率，甚至引起乳化。利用斜率法和红外检测技术探讨了Al ³⁺萃取物和萃取剂P204-P350的形成，该萃取剂以AlCl [（HA）₂ ] ₂ P350 _{（o）的形式}进入有机相。