Solvent extraction is a widely used separation technique in extractive metallurgy. A conventional solvent extraction system consists of an aqueous phase and an immiscible organic phase. In this work, we show that replacement of water by a polar organic solvent can lead to superior metal separations. Cobalt(II) and samarium(III) chlorides dissolved in water and ethylene glycol (EG), respectively, with LiCl as chloride source, were extracted by Aliquat 336 diluted in toluene. Both cobalt and samarium were extracted from the aqueous solutions, but cobalt was extracted more efficiently from the ethylene glycol solutions than from the aqueous solutions, whereas samarium was not extracted at all from the ethylene glycol solutions. As a result, cobalt and samarium could be separated completely in a single extraction step from ethylene glycol solutions. The mechanisms of cobalt extraction by Aliquat 336 from the ethylene glycol and aqueous solutions were found to be similar, as validated by slope analysis and UV–VIS absorption spectroscopy. Samarium was extracted from the aqueous solution through the salting-out effect of LiCl. Interestingly, LiCl has a much lower salting-out effect for samarium in ethylene glycol than in water due to the lower dielectric constant of ethylene glycol and the lower solubility of LiCl in ethylene glycol. Consequently, samarium is not salted out from ethylene glycol, leading to a very efficient separation of cobalt and samarium. This separation effect can also be applied to the separation of other transition metal and rare-earth metal pairs, including iron/neodymium and zinc/europium.

溶剂萃取是萃取冶金中广泛使用的分离技术。常规的溶剂萃取系统由水相和不混溶的有机相组成。在这项工作中，我们表明用极性有机溶剂代替水可以导致优异的金属分离效果。用稀释在甲苯中的Aliquat 336萃取分别溶解在水和乙二醇（EG）中的氯化钴（II）和sa（III），并以氯化锂为氯化物。从水溶液中提取钴和sa，但是从乙二醇溶液中提取钴比从水溶液中提取钴更有效，而从乙二醇溶液中根本没有提取sa。结果，可以在一个萃取步骤中从乙二醇溶液中完全分离出钴和mar。通过斜率分析和UV-VIS吸收光谱法证实，Aliquat 336从乙二醇和水溶液中萃取钴的机理是相似的。of通过LiCl的盐析作用从水溶液中提取。有趣的是，由于乙二醇的介电常数较低，而LiCl在乙二醇中的溶解度较低，因此LiCl在乙二醇中的sa盐析作用要比在水中低得多。因此，sa不会从乙二醇中盐析出来，从而非常有效地分离了钴和sa。这种分离效果还可以应用于其他过渡金属和稀土金属对的分离，包括铁/钕和锌/ eur。