Electrochemistry of rare earth fluoride molten salts

Kaneko, Akira; Yamamoto, Yoshihiko; Okada, C.

doi:10.1016/0925-8388(93)90305-7

Cited by 35 publications

(16 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given that the electrolyte has an excess of F -, [NdF6] 3− and [NdOF5] 4− coexist. Which of the two species will be predominantly involved in the neodymium deposition reaction should depend on the neodymium oxyfluoride ions/neodymium fluoride ions molar ratio [17,29], electrode potential, and current density applied [24]. The dissolution of Nd 2 O 3 in molten fluoride (LiF-NdF 3 ) is a diffusion-controlled process which can be accelerated if the temperature and NdF 3 concentration in the melt are increased [30].…”

Section: Resultsmentioning

confidence: 99%

“…Fluoride electrolytes are considered more suitable because of their higher conductivity, lower hygroscopy, and higher current efficiency of the neodymium deposition compared to the chloride melts [17,18]. Most of the molten fluoride electrolytes for Nd electrowinning was found in the literature reference LiF (NaF or KF) with CaF 2 (or BaF 3 ) [8,10,[17][18][19][20][21][22][23][24][25][26][27][28][29]. NdF 3 and Nd 2 O 3 serve as sources of neodymium in such fluoride melts.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

View full text Add to dashboard Cite

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.

show abstract

Section: Resultsmentioning

confidence: 99%

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

View full text Add to dashboard Cite

show abstract

“…The electrolytic bath contains rare earth fluorides, LiF, BaF 2 , and CaF 2 . Figure 2.9.13 shows the phase diagram of NdF 3 -LiF-BaF 2 system [28]. It is difficult to apply NdF 3 single salt to the electrolytic baths due to its high melting point of 1378 C. However, melting temperature is decreased by mixing LiF and BaF 2 .…”

Section: Reduction-diffusion Processmentioning

confidence: 98%

Rare Earth, Titanium Group Metals, and Reactive Metals Production

Takeda

Uda

Okabe

2014

Treatise on Process Metallurgy

View full text Add to dashboard Cite

“…Metallic neodymium electrodeposition can take place in fused chloride salts [2][3][4][5][6][7][8][9][10][11][12][13], but this process has several drawbacks, such as the evolution of chlorine gas at the anode and low faradic yield. Thus, neodymium metal is currently produced by electrowinning from neodymium oxide in a molten fluoride media containing high amounts of NdF 3 (up to 87 mass %) [14].…”

Section: Introductionmentioning

confidence: 99%

Neodymium electrowinning into copper-neodymium alloys by mixed oxide reduction in molten fluoride media

Ciumag

Gibilaro

Massot

et al. 2016

Journal of Fluorine Chemistry

View full text Add to dashboard Cite

The possibility of neodymium electrowinning from neodymium oxide using a reducing agent (RA) produced in-situ by solvent reduction was investigated in molten LiF-CaF 2-Li 2 O between 900 C and 1040 C. Nd 2 O 3 galvanostatic electrolyses were performed and reaction products were analyzed by SEM, XRD and electron-probe microscopy. Metallic neodymium was not directly obtained, due to several limitations for Nd 2 O 3 reduction: low electrical conductivity, unfavourable Pilling-Bedworth coefficient and formation of a dense insulating CaO layer on the sample surface. Consequently, the reduction of a pellet made of a neodymium oxide-metallic oxide mixture was carried out as an alternative pathway. Nd 2 O 3-CuO reduction led to metallic neodymium production in the form of liquid Cu-Nd alloys. A reaction mechanism was proposed based on these experimental results:

show abstract

Electrochemistry of rare earth fluoride molten salts

Cited by 35 publications

References 1 publication

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

Rare Earth, Titanium Group Metals, and Reactive Metals Production

Neodymium electrowinning into copper-neodymium alloys by mixed oxide reduction in molten fluoride media

Contact Info

Product

Resources

About