Abstract In this study, synergistic effect of Cyanex 572 mixed with TBP on the extraction and separation of six selected light, medium and heavy rare earth elements (REE), namely neodymium (Nd), praseodymium (Pr), samarium (Sm), europium (Eu), terbium (Tb), and erbium (Er), from the chloride medium was investigated. The results demonstrated that sole TBP is not a suitable extractant for the separation of the REEs from the chloride media. However, Cyanex 572 was identified as a suitable extractant for the separation of heavy REEs, Er, and Tb. At initial pH (pHi) of 1.5, the mixture of 25% TBP + 75% Cyanex 572 extracted about 70% and 85% of Er and Tb, respectively. The separation factor (SF) results of some couples were noteworthy: SFEr/Pr = 30.08, SFEr/Nd = 29.95, SFTb/Pr = 12.22, SFTb/Nd = 12.16, SFEr/Sm = 9.96. Furthermore, the extraction mechanism of these two heavy REEs was studied using slope analysis and Fourier transform infrared measurements (FT-IR). The results showed that Er and Tb were extracted as ErCl2R(HR)3TBP and TbCl2R(HR)3TBP complexes (presumably R and HR refers to Cyanex 572), respectively. The FT-IR spectra confirmed these obtained results qualitatively.

中文翻译：

---

使用 TBP 和 Cyanex 572 从氯化物介质中分离和溶剂萃取稀土元素（Pr、Nd、Sm、Eu、Tb 和 Er）

摘要 本研究中，Cyanex 572 与 TBP 混合对六种选定的轻、中、重稀土元素 (REE)，即钕 (Nd)、镨 (Pr)、钐 (Sm)、铕的萃取和分离的协同作用研究了氯化物介质中的 (Eu)、铽 (Tb) 和铒 (Er)。结果表明，单独的 TBP 不是从氯化物介质中分离 REE 的合适萃取剂。然而，Cyanex 572 被确定为分离重 REE、Er 和 Tb 的合适萃取剂。在 1.5 的初始 pH (pHi) 下，25% TBP + 75% Cyanex 572 的混合物分别提取了约 70% 和 85% 的 Er 和 Tb。一些夫妇的分离因子（SF）结果值得注意：SFEr/Pr = 30.08，SFEr/Nd = 29.95，SFTb/Pr = 12.22，SFTb/Nd = 12.16，SFEr/Sm = 9.96。此外，使用斜率分析和傅里叶变换红外测量 (FT-IR) 研究了这两种重稀土的提取机制。结果表明，Er 和 Tb 分别提取为 ErCl2R(HR)3TBP 和 TbCl2R(HR)3TBP 复合物（推测 R 和 HR 指的是 Cyanex 572）。FT-IR 光谱定性地证实了这些获得的结果。