Chemical and Electrochemical Extraction of Ytterbium from Molten Chlorides in Pyrochemical Processes

Castrillejo, Y.; Fernández, Pablo S.; Medina, Jesús; Vega, Marisol; Barrado, E.

doi:10.1002/elan.201000421

Cited by 62 publications

(42 citation statements)

References 39 publications

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“…Rare earth metals are increasing in importance, particularly in the production of permanent magnets, energy, high technology, and electronic devices [1][2][3][4]. Due to their rare occurrence in nature and the difficulties encountered in extracting and refining them, rare earth metals are expensive.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Electrochemical Behaviour and Deposition Mechanism of Neodymium in NdF3–LiF–Nd2O3 Melt on Mo Electrode

Cvetković

Feldhaus

Vukićević

et al. 2020

Metals

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Neodymium was electrochemically deposited from NdF3–LiF–Nd2O3 molten salt electrolyte onto the Mo electrode at temperatures close to 1273 K. Cyclic voltammetry and chronoamperometry measurements were the applied electrochemical methods. Metallic neodymium is obtained by potentiostatic deposition. The optical microscopy and XRD were used to analyze the electrolyte, the working electrode surface, and the deposit on the electrode. It was established that Nd(III) ions were reduced to Nd metals in two steps: Nd(III) + e− → Nd(II) at potential ≈−0.55 V vs. W and Nd(II) + 2e− → Nd(0) at ≈−0.83 V vs. W. Both of these processes are reversible and under mass transfer control. Upon deposition under the regime of relatively small deposition overpotential of −0.10 V to −0.20 V, and after the electrolyte was cooled off, Nd metal was observed at the surface of the Mo electrode. CO and CF4 were gases registered as being evolved at the anode. CO and CF4 evolution were observed in quantities below 600 ppm and 10 ppm, respectively.

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Section: Introductionmentioning

confidence: 99%

Investigation on the Electrochemical Behaviour and Deposition Mechanism of Neodymium in NdF3–LiF–Nd2O3 Melt on Mo Electrode

Cvetković

Feldhaus

Vukićević

et al. 2020

Metals

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“…30,[33][34][35] The deposition of Yb(II) in the melt containing Mg(II) is considered to be caused by depolarization, which is called underpotential deposition (UPD). According to the equation:…”

Section: Resultsmentioning

confidence: 99%

Fabrication of Yb-Rich Mg–Li–Yb Alloys via Co-Reduction of Mg, Li and Yb

Yan

Zhang

et al. 2014

J. Electrochem. Soc.

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Anhydrous K 3 YbCl 6 was obtained via solid-phase reaction from Yb 2 O 3 with NH 4 Cl and KCl as chlorination agents. Electrochemical behaviour of ytterbium ions was investigated in LiCl-KCl-MgCl 2 -K 3 YbCl 6 melt at 903 K on W electrodes. The signal corresponding to Mg 2 Yb intermetallic compound was detected at the potential close to that of the formation of Mg-Li alloy. Bulk Mg-Li-Yb alloys, characterized by X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM), were prepared via electrochemical co-reduction of Mg, Li and Yb on W electrodes. Yb-rich Mg-Li-Yb alloys with different constituents were obtained via the change of the concentration of K 3 YbCl 6 .The extensive application of light alloys to substitute for conventional denser engineering materials not only relieves the energy crisis but also alleviates environmental pollution. Mg and Li, whose densities are 1.738 and 0.534 g cm −3 , can form Mg-Li alloy with low density (1.35-1.65 g cm −3 ), respectively. Mg-Li alloy is known as the lightest metallic structural material, which is also called superlight alloy. Moreover, due to its high specific stiffness, high electrical and thermal conductivities, Mg-Li alloy is increasingly utilized as structural materials in the fields of aerospace, weapons and automobiles industries. 1-4 Whereas, poor thermal stability and corrosion resistivity limit the widespread application of Mg-Li alloy. Rare earth (RE) elements and their alloys with a light metal (i.e. Al, Mg) have been widely used as additive to obtain high-performance Mg-Li based alloys. [5][6][7][8][9][10] Generally, the method for fabrication of Mg-Li-RE master alloys is primary mechanical alloying, which requires pure Mg, Li and RE metals leading to high pollution, high-energy consumption and high cost. Additionally, for variable valence rare earth elements it is impossible to obtain their pure metals via reduction of their halides using Ca or Li as a reducer because it can form stable bivalent halides. To overcome these problems, molten salt electrochemical process has been widely investigated for the preparation of rare earth alloy for its easy mass production and simple procedure. In molten salt, a feasible route to obtain RE metals is directly alloying with other metals to form corresponding intermetallics in molten chlorides or fluorides on inert and reactive electrodes. 11-15 This is because the formation potentials of intermetallic compounds locate between the deposition potentials of each pure metal, 16,17 which are usually much more positive than those of common solvents (LiCl-KCl, NaCl, CsCl). Massot and his group 16,17 have successfully obtained Al-Sm, Al-Nd and Al-Ce alloys via co-reduction of Al and RE (RE=Sm, Nd and Ce) in molten fluorides on inert electrodes. Castrillejo et al. 18 have obtained Al-Sm alloys via potentiostatic electrolysis on Al electrodes in LiCl-KClAlCl 3 -SmCl 3 melts. Nohira et al. 19 have prepared Nd-Ni alloys in molten NaCl-KCl-NdCl 3 on Ni electrodes.Our group has prepared Mg-Yb and...

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“…Since deposited Dy metal react with Mg and diffuse into the Mg electrode (already deposited on the Mo electrode), the electrode potential gradually shifts to more positive values. During this process, a potential plateau can be observed when the composition of the electrode surface is within a range of a two phase coexisting state [26][27][28][29] . In the beginning, the potential stays at around -1.91 V and -1.82 V (plateau 1 and 2), which is interpreted as the formation of Mg-Dy alloys and Mg metal.…”

Section: Electrochemical Behaviour Of Smcl 3 and Dycl 3 In Licl-kcl-mmentioning

confidence: 98%

Separation of SmCl3 from SmCl3-DyCl3 system by Electrolysis in KCl-LiCl-MgCl2 Molten Salts

et al. 2013

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Pyrometallurgical reprocessing of spent nuclear fuel was now considered as one of the most promising options for an innovative nuclear fuel cycle. In this paper, the electrochemical behavior of Sm(III) and Dy(III) was studied by cyclic voltammetry in KCl-LiCl molten salts. Addition of magnesium chloride resulted in positive deposition potential of Dy(III), lower electrolysis temperature and higher recovery ratio of rare earth. According to different deposition potentials of Sm(III) and Dy(III), electrolysis in the molten KCl-LiCl-MgCl 2 system constituted the main step in this reprocess, where SmCl 3 was separated from the SmCl 3 -DyCl 3 system at -2.20 V (vs. Ag/AgCl reference electrode) and the DyCl 3 were formed the Dy-Mg alloys. It was proved that the main structures of the obtained alloys were Dy and DyMg 3 without Sm by the analysis of XRD of alloys.

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Chemical and Electrochemical Extraction of Ytterbium from Molten Chlorides in Pyrochemical Processes

Cited by 62 publications

References 39 publications

Investigation on the Electrochemical Behaviour and Deposition Mechanism of Neodymium in NdF3–LiF–Nd2O3 Melt on Mo Electrode

Investigation on the Electrochemical Behaviour and Deposition Mechanism of Neodymium in NdF3–LiF–Nd2O3 Melt on Mo Electrode

Fabrication of Yb-Rich Mg–Li–Yb Alloys via Co-Reduction of Mg, Li and Yb

Separation of SmCl3 from SmCl3-DyCl3 system by Electrolysis in KCl-LiCl-MgCl2 Molten Salts

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