Extractants for rare earth metals

Abstract

The separation of trivalent rare earth metals is perhaps the most serious challenge associated with a closed fuel cycle. The choice of ligand as extractant, which must be selective and efficient in conditions of high radiation environment, plays an important role. In this review there are the main examples of extractants for f-elements used in the present 10-20 years. Экстрагенты для редкоземельных металловРазделение трехвалентных редкоземельных металлов, возможно, является самым се-рьезным вызовом, связанным с замкнутым топливным циклом. Важную роль играет выбор лиганда в качестве экстрагента, который должен быть селективным и надежным в условиях повышенной радиации среды. В данном обзоре приведены основные примеры экстрагентов для f-элементов, применяющихся в последнии 10-20 лет.Ключевые слова: редкоземельные металлы; фосфорорганические соединения; краунэ-фиры; поданды; каликсарены; амиды дигликолевой кислоты.

Separation of Rare Earth Elements (REE) by Ion Interaction Chromatography (IIC) Using Diglycolic Acid (ODA) as a Complexing Agent

“…It can be shown that making use of the Eqs. (1)(2)(3)(4)(5), this is equivalent to the formula: where: ′ LnL3 is bed distribution coefficient of the complex ion.…”

“…In the last decades, the problem of recovery of precious and rare metals from various forms of electronic wastes gained considerable attention and has been discussed in several papers and reviews [14][15][16]. Preliminary separation of REE from other elements is usually achieved by solvent extraction and/ or ion exchange [3][4][5].…”

“…Separation of REE is difficult because of similarity of their chemical properties and therefore only a few techniques like solvent extraction, ion exchange and various forms of chromatography have gained wider acceptance for technological and analytical purposes. Reviews dealing with the separation of REE were recently published [3][4][5]. Several carboxylic and aminocarboxylic acids have been employed for the column separation of REE by ion exchange chromatography (IEC) or ion interaction chromatography (IIC) in cation or anion exchange modes.…”

Increasing the depth of apatite processing by extracting rare-earth elements

“…Their high selectivity can be achieved by changing the glycol chain numbers and introducing substituents to their structure. Such operations limit the availability of crown ethers as extractants for REE on a commercial scale [16]. Besides, there is data about their poor effectiveness in acidic solutions with low pH values [17].…”