Light, Middle, and Heavy Rare-Earth Group Separation: A New Approach via a Liquid鈥揕iquid鈥揕iquid Three-Phase System

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• 作者：Na Sui ; Kun Huang ; Chao Zhang ; Ning Wang ; Fuchun Wang ; Huizhou Liu
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2013
• 出版时间：May 1, 2013
• 年：2013
• 卷：52
• 期：17
• 页码：5997-6008
• 全文大小：599K
• 年卷期：v.52,no.17(May 1, 2013)
• ISSN：1520-5045

文摘

The present work puts forward a new strategy to achieve group separation of light, middle, and heavy rare-earth ions by liquid鈥搇iquid鈥搇iquid three-phase systems. Experimental results indicated that heavy rare-earth ion, Yb(III), can be selectively extracted into the organic top phase, while middle rare-earth ion, Eu(III), and light rare-earth ion, La(III), can be enriched, respectively, into PEG-rich middle phase and (NH₄)₂SO₄-rich bottom aqueous phase of Cyanex272/PEG/(NH₄)₂SO₄鈥揌₂O three-liquid-phase system. Various influences of aqueous pH, (NH₄)₂SO₄ concentrations, complexing agents, polymers, and their added amount on three-liquid-phase separation of La, Eu, and Yb were investigated. Besides, a possible partitioning mechanism for three rare-earth ions was discussed. The present work highlights the possibility of employing the discrepancy in selective partitioning behaviors of different rare-earth ions (such as La, Ce, Eu, Gd, Yb, and Lu) into different liquid layers of three-liquid-phase system to achieve one-step group separation of light, middle, and heavy rare-earth ions. In comparison with traditional organic-aqueous biphasic extraction for group separation of rare-earth ions, which require multiple steps of pH adjustments and repeated separation, the three-liquid-phase approach exhibits obvious advantages for future industrial application.