Recent Advances in Rare Earth Separation and Extraction

Dear Colleagues,

Rare earth is globally recognized as a key strategic metal, known as the "modern industrial vitamin." Because of its excellent optical, electrical, magnetic, and other properties, it is widely used in emerging industries such as national defense and high-end intelligent equipment. The green and efficient separation and purification of rare earths is an important material support for the development of new materials. Due to the polymetallic symbiosis of rare earth minerals, complex composition, similar physical and chemical properties of elements, and the small separation coefficient, the separation and purification of rare earths is a difficult and long process, which is recognized as one of the major problems in the world's non-ferrous metal industry.

Solvent extraction has been convincingly proved to be an effective method for the recovery and separation of rare earths. Exploring the extraction mechanism in depth and developing new separation methods are both challenging and meaningful. The new integrated process of rare earth separation has important theoretical and practical application value.

This Special Issue aims to collect recent advances in rare earth extraction and separation, with a particular reference to new system and equipment developments. The expected contributions (original research papers and review articles) can include rare earth extraction and separation technologies, new extractant syntheses, novel adsorbents and extractive resins, new extraction equipment developments, new processes, the recovery and separation of rare earth secondary resources, extraction interfacial chemistry studies, calculations, etc. The scope of the Issue includes but is not limited to the above aspects.

Dr. Junlian Wang
Dr. Na Sui
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Separations is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• rare earths
• solvent extraction
• separation technology
• extraction chromatography
• recovery
• low concentration enrichment
• adsorption
• calculations

Title: Hierarchically ordered macroporous-mesoporous (HOM-m) MgFe2O4/MgO for highly efficient adsorption of Ce(III) and La(III): Experimental study and DFT calculation analysis
Authors: Lina Zhang; Jiarui Lu; Baixiong Liu
Affiliation: Jiangxi University of Science and Technolog
Abstract: This study employed a template method to prepare a highly ordered and interconnected porous HOM-m MgFe2O4/MgO rare-earth ion-efficient adsorbent. The specific surface area of the adsorbent was as high as 130 m2/g, with saturation adsorption capacities for Ce(Ⅲ) and La(Ⅲ) of 5689.69 mg/g and 2123.50 mg/g, respectively. The adsorbent exhibited superparamagnetism, enabling efficient and rapid separation from an aqueous solution using a magnet. The adsorption results indicated that the adsorption mechanism of HOM-m MgFe2O4/MgO towards Ce(III) and La(III) primarily involved the ion exchange and redox reactions between Mg(II) hydrolyzed from MgO and Ce(III)/La(Ⅲ), as well as the electrostatic attraction between MgFe2O4 and Ce(Ⅲ)/La(Ⅲ). Density functional theory (DFT) calculations revealed that the adsorption process was driven by the interaction of Ce(III) and La(III) ions with the surface oxygen atoms of MgFe2O4/MgO, with MgFe2O4/MgO exhibiting a higher affinity and stronger adsorption effect towards Ce(III) than La(III). Adsorption cycling experiments demonstrated that even after three cycles, HOM-m MgFe2O4/MgO maintained good removal efficiency for Ce(III) and La(III). Therefore, this adsorbent shows promise as an effective material for removing Ce(III) and La(III) and has significant implications for the remediation of water resources in ion adsorption-type rare earth mining areas