Solid-phase extraction and separation of heavy rare earths from chloride media using P227-impregnated resins
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RARE METALS
ORIGINAL ARTICLE
Solid-phase extraction and separation of heavy rare earths from chloride media using P227-impregnated resins Bin Yang, Suo-Zhi Wu, Xin-Yu Liu, Zeng-Xin Yan, Yu-Xue Liu, Qi-Song Li, Feng-Shan Yu, Jun-Lian Wang*
Received: 21 April 2019 / Revised: 20 August 2019 / Accepted: 22 July 2020 Ó The Nonferrous Metals Society of China and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract A solid-phase extraction resin SIRs-P227/XAD7HP was prepared by impregnating extractant P227 onto macroporous resin XAD-7HP beads. SIRs-P227/XAD-7HP beads were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS). The adsorption kinetics, particle size effect, adsorption isotherm, pHequilibrium–lgD relationship (where D is distribution coefficient), desorption, adsorption selectivity for heavy rare earths, and impurity ions were studied. The results showed that the adsorption kinetics of Lu(III) on the SIRs-P227/XAD-7HP beads fitted the Morris–Weber model best. The adsorbance decreased as the particle size increased. The pHequilibrium–lgD relationship fitted well with a straight line, and the slope was 1.56. The experimental data fitted well with Langmuir adsorption. The calculated maximum adsorption capacity was 23.8 mgg-1, while the experimental datum was 22.7 mgg-1 at the given conditions. The adsorbed Lu(III) can be easily stripped by 0.1 molL-1 HCl. The adsorption selectivity of SIRs-P227/XAD-7HP for heavy REs exhibited the following order: Lu [ Yb [ Tm [ Er [ Ho. The adjacent heavy rare earth (RE) separation factors bLu/Yb, bYb/Tm, bTm/Er, and bEr/Ho were 1.57, 3.00, 3.03, and 2.23, respectively, at liquid/solid ratio (L/S) equal to 3:20. The adsorption selectivity for impurity ions exhibited the B. Yang, S.-Z. Wu, X.-Y. Liu, Z.-X. Yan, Y.-X. Liu, Q.-S. Li, J.-L. Wang* School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China e-mail: [email protected] F.-S. Yu Jiangxi Province Han’s Precious Metals Co., Ltd, Shangrao 335500, China
following order: Fe [ Lu [ Tm [ Zn [ Mg [ Ca [ Ho [ Co [ Ni [ Cu [ Al. Keywords Solid-phase extraction; Solvent-impregnated resins; P227; Heavy rare earths
1 Introduction Rare earths (REs), known as ‘‘the vitamins of modern industry’’ and ‘‘the treasure house of new materials,’’ are a group of 17 metallic elements, including Sc, Y, and 15 lanthanides. REs always coexist or accompany each other in nature. They are very similar in physical and chemical properties due to their similarity in atomic structures. Thus, it is very difficult to separate REs from each other and obtain high-purity single-RE products. Hundreds of stages are required to separate them completely by solvent extraction. Additionally, the RE grades in the raw ores are always low, especially the heavy REs. For example, only 0.05%–0.30% REs are present in the ion-adsorbed rare earth ores in south China. This causes the low RE concentra
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