scholarly journals Concentration and Separation of Heavy Rare-Earth Metals at Stripping Stage

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1317
Author(s):  
Olga Cheremisina ◽  
Vasiliy Sergeev ◽  
Alexander Fedorov ◽  
Daria Alferova
Keyword(s):  
Rare Earth ◽  
Oxalic Acid ◽  
Organic Phase ◽  
Tributyl Phosphate ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Acid Solutions ◽  
Extractant Concentration ◽  
Heavy Rare Earth ◽  
Separation Factors

The separation and concentration processes of heavy rare-earth metals—yttrium, ytterbium, erbium, and dysprosium—during stripping from the organic phase based on di-2-ethylhexylphosphoric acid (D2EHPA, or DEHPA) solutions were investigated in this work. Optimal conditions providing high separation factors of rare-earth metals (REM) and their extraction degree to the aqueous phase were determined. The usage of sulfuric acid solutions with a concentration of 2–6 mol/L, depending on the type of extracted rare-earth element, was proposed as a stripping agent for rare-earth metals (REM), and the usage of oxalic acid solution was proposed as an iron stripping solution from the organic phase. To increase the REM stripping efficiency, the antagonistic effect of tributyl phosphate in the di-2-ethylhexylphosphoric acid-kerosene-tributyl phosphate system was considered. The possibility of increasing the capacity of the organic solvent by cleaning the organic phase from iron ions using oxalic acid solutions was revealed. The influence of temperature, aqueous and organic phase ratio, stirring rate, and re-extractant concentration on the distribution and separation factors of adjacent heavy rare-earth-metal (HREM) pairs during the re-extraction process were determined. A schematic diagram of the laboratory-tested separation process of heavy rare-earth metals into individual components with the obtaining of yttrium and ytterbium concentrates containing more than 99% of the target components was proposed.

FEATURES OF THE MAGNETIC STATE IN AMORPHOUS RE–TM AND RE–TM–B MAGNETS (review)

2021 ◽  
pp. 43-58
Author(s):  
R.B. Morgunov ◽  
◽  
D.V. Korolev ◽  
R.A. Valeev ◽  
V.P. Piskorskiy ◽  
...  
Keyword(s):  
Rare Earth ◽  
Amorphous Alloys ◽  
Magnetic State ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Spin Reorientation ◽  
Heavy Rare Earth ◽  
Temperature Dependences ◽  
Magnetic States ◽  
Amorphous Magnets

Provides an overview of the magnetism features of amorphous magnets of the RE–TM and RE–TM–B alloys (RE – rare earth metal, TM – transition metal, B – boron). Magnetic states in amorphous alloys, the effect of the single-ionic anisotropy of heavy rare-earth metals on local disorder and spin frustrations in an amorphous body, and some spin-reorientation transitions observed in such compounds are presented. It is shown that the identification of the spin-glass state can be achieved by detecting specific features on the field and temperature dependences of the magnetic moment and magnetic susceptibility of the sample.

High Pressure Phase Transformations in Heavy Rare Earth Metals and Connections to Actinide Crystal Structures

2008 ◽  
Vol 1104 ◽  
Author(s):  
Yogesh K. Vohra ◽  
Bagvanth Reddy Sangala ◽  
Andrew K. Stemshorn ◽  
Kevin M. Hope
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
High Pressures ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Heavy Rare Earth ◽  
High Pressure Studies ◽  
Volume Collapse ◽  
Diamond Anvil ◽  
Heavy Actinide

AbstractHigh-pressure studies have been performed on heavy rare earth metals Terbium (Tb) to 155 GPa and Holmium (Ho) to 134 GPa in a diamond anvil cell at room temperature. The following crystal structure sequence was observed in both metals hcp ⟶ Sm-type ⟶ dhcp ⟶ distorted fcc (hR-24) ⟶ monoclinic (C2/m) with increasing pressure. The last transformation to a low symmetry monoclinic phase is accompanied by a volume collapse of 5 % for Tb at 51 GPa and a volume collapse of 3 % for Ho at 103 GPa. This volume collapse under high pressure is reminiscent of f-shell delocalization in light rare earth metal Cerium (Ce), Praseodymium (Pr), and heavy actinide metals Americium (Am) and Curium (Cm). The orthorhombic Pnma phase that has been reported in Am and Cm after f-shell delocalization is not observed in heavy rare earth metals under high pressures.

scholarly journals The recovery of rare earth metals from WEEE leaching solution via liquid-liquid extraction

2018 ◽  
Vol 20 (4) ◽  
pp. 719-724 ◽  
Keyword(s):  
Rare Earth ◽  
Oxalic Acid ◽  
Organic Phase ◽  
Electronic Waste ◽  
Rare Earth Metals ◽  
Extraction Process ◽  
Liquid Extraction ◽  
The Sustainable Development ◽  
Liquid Liquid Extraction ◽  
Leaching Solution

<p>The recovery of rare earth metals (REMs) from end-of-life products, such as Waste Electrical and Electronic Equipment (WEEE), is drawing great attention as an attractive strategy for promoting the sustainable development. The hydrometallurgical technique of solvent extraction has been reported to be one of the most interesting method to recover REMs. However, when applied to WEEE, this process is challenged by the heterogeneous composition of electronic waste, completely different from other solid matrices, and it still has much rooms of improvements. This study investigated the extraction, stripping and recovery of REMs from a WEEE leaching solution using Versatic 10 as carrier in the organic phase and oxalic acid as stripping agent. A factorial design was carried out to evaluate the simultaneous effects of factors as the feed phase pH and the concentrations of both extractant and organic phase modifier in the extraction process. Cerium, lanthanum and yttrium were extracted at high percentages using 200 mM of Versatic 10, loaded by 100 mM of TBP in kerosene at pH 7. Moreover, 750 mM of oxalic acid successfully stripped and recovered 7.63 and 13.82 mg/kg of lanthanum and yttrium, respectively.</p>

Magnetic susceptibility of liquid heavy rare earth metals

1979 ◽  
Vol 40 (C5) ◽  
pp. C5-260-C5-261 ◽  
Author(s):  
M. Müller ◽  
E. Huber ◽  
H.-J. Güntherodt
Keyword(s):  
Magnetic Susceptibility ◽  
Rare Earth ◽  
Rare Earth Metals ◽  
Heavy Rare Earth

scholarly journals Dipolar Excitations at theLIIIX-Ray Absorption Edges of the Heavy Rare-Earth Metals

2007 ◽  
Vol 99 (24) ◽  
Author(s):  
S. D. Brown ◽  
P. Strange ◽  
L. Bouchenoire ◽  
B. Zarychta ◽  
P. B. J. Thompson ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Heavy Rare Earth ◽  
Absorption Edges

scholarly journals Dehydration of Biomass-Derived Butanediols over Rare Earth Zirconate Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1392
Author(s):  
Asami Matsuda ◽  
Yoshitaka Matsumura ◽  
Kazuki Nakazono ◽  
Fumiya Sato ◽  
Ryoji Takahashi ◽  
...  
Keyword(s):  
Rare Earth ◽  
Flow Reactor ◽  
Rare Earth Metals ◽  
Fluorite Structure ◽  
Catalytic Performance ◽  
High Specific Surface Area ◽  
Heavy Rare Earth ◽  
High Crystallinity ◽  
Unsaturated Alcohols ◽  
Selective Formation

The aim of this work is to develop an effective catalyst for the conversion of butanediols, which is derivable from biomass, to valuable chemicals such as unsaturated alcohols. The dehydration of 1,4-, 1,3-, and 2,3-butanediol to form unsaturated alcohols such as 3-buten-1-ol, 2-buten-1-ol, and 3-buten-2-ol was studied in a vapor-phase flow reactor over sixteen rare earth zirconate catalysts at 325 °C. Rare earth zirconates with high crystallinity and high specific surface area were prepared in a hydrothermal treatment of co-precipitated hydroxide. Zirconates with heavy rare earth metals, especially Y2Zr2O7 with an oxygen-defected fluorite structure, showed high catalytic performance of selective dehydration of 1,4-butanediol to 3-buten-1-ol and also of 1,3-butanediol to form 3-buten-2-ol and 2-buten-1-ol, while the zirconate catalysts were less active in the dehydration of 2,3-butanediol. The calcination of Y2Zr2O7 significantly affected the catalytic activity of the dehydration of 1,4-butanediol: a calcination temperature of Y2Zr2O7 at 900 °C or higher was efficient for selective formation of unsaturated alcohols. Y2Zr2O7 with high crystallinity exhibits the highest productivity of 3-buten-1-ol from 1,4-butanediol at 325 °C.

Antiferromagnetism of Disilicides of Heavy Rare Earth Metals

1966 ◽  
Vol 21 (2) ◽  
pp. 274-278 ◽  
Author(s):  
Kazuko Sekizawa ◽  
Kō Yasukōchi
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Heavy Rare Earth
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