Oxide solubility and Raman spectra of NdF3–LiF–KF–MgF2–Nd2O3 melts

Stefanidaki, E; Photiadis, G. M.; Kontoyannis, Christos G.; Vik, A. F.; Østvold, Terje

doi:10.1039/b111563b

Cited by 60 publications

(49 citation statements)

References 13 publications

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“…The deviation from linearity observed in the LnF 3 -LiF systems indicates the existence of more than two kinds of fluorine environments. This observation is in agreement with the work of Papatheodorou and his co-workers [13,14] using Raman spectroscopy. They have shown that the LnF 3 -AlkF melts (Alk = alkalin) should consist of LnX 3− 6 octahedral species, more or less connected, depending on the LnF 3 content in the melt.…”

Section: Resultssupporting

confidence: 92%

“…They are indeed highly corrosive and volatile, and the melting temperatures are high (700-1800 K). Most of the previous work deals with the electrochemical [8,9] and thermodynamic properties [10,11] and very few spectroscopic studies [12][13][14][15] have been done. The latter are important to provide coordination numbers and interatomic distances and are helpful for electrochemical experiment analysis and for building potentials in numerical simulations.…”

Section: Introductionmentioning

confidence: 99%

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Local Structure Analogy of Lanthanide Fluoride Molten Salts

2005

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The objective of this paper is to describe the local structure of lanthanide fluoride melts of nuclear interest. An experimental approach combining NMR and EXAFS spectroscopy, both sensitive to the microstructure of solid or liquid materials, is presented. These techniques can be used to determine the coordination number, the nature of neighbors, and then to identify the complex formation. NMR and EXAFS spectroscopy have been applied to the molten LaF 3 -LiF and LuF 3 -LiF systems. The influence of melt compositions and temperature was studied.

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Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Local Structure Analogy of Lanthanide Fluoride Molten Salts

2005

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“…In-situ formation of REF 3 is very important since the solubility of REOs is very low in molten fluorides [20]. Further, an additional advantage is that the formation of rare earth oxyfluoride is likely to be inhibited.…”

Section: Discussionmentioning

confidence: 99%

“…Further, an additional advantage is that the formation of rare earth oxyfluoride is likely to be inhibited. Stefanidaki et al [20] have studied the oxide solubility and Raman spectra of Nd 2 O 3 in the molten alkali fluorides. The authors have reported that the octahedral [NdF 6 ] 3-anion is the dominant complex in the eutectic NdF 3 -LiF melt system.…”

Section: Discussionmentioning

confidence: 99%

Electrochemical Extraction of Rare Earth Metals in Molten Fluorides: Conversion of Rare Earth Oxides into Rare Earth Fluorides Using Fluoride Additives

Abbasalizadeh

Malfliet

Seetharaman

et al. 2017

J. Sustain. Metall.

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In the present research on rare earth extraction from rare earth oxides (REOs), conversion of rare earth oxides into rare earth fluorides with fluoride fluxes is investigated in order to overcome the problem of low solubility of the rare earth oxides in molten fluoride salts as well as the formation of oxyfluorides in the fluorination process. Based on thermodynamic calculations, a series of experiments were performed for converting the rare earth oxides into rare earth fluorides using AlF 3 , ZnF 2 , FeF 3 , and Na 3 AlF 6 as fluorinating agents in a LiF-Nd 2 O 3 system. The formation of neodymium fluoride as a result of the reactions between these fluxes and neodymium oxide is confirmed. The rare earth fluoride thus formed can subsequently be processed through the electrolysis route in the same reactor, and rare earth metal can be produced as the cathodic deposit. In this concept, the REO dissolution in molten fluorides would become unnecessary due to the complete conversion of the oxide into the fluoride, REF 3 . The results of XRD and EPMA analysis of the reacted samples indicate that AlF 3 , ZnF 2 , and FeF 3 can act as strong fluorinating agents for the neodymium oxide giving rise to a complete conversion of neodymium oxide into neodymium fluoride.

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“…In recent years, the solubility of REO in fluoride melts was widely researched [10][11][12][13][14][15][16][17][18][19][20][21]. It was found that the solubility was relatively low and the melts with high temperature and strong corrosiveness so that there were difficulties for accurate measuring the concentration of REO in fluoride melts.…”

Section: Introductionmentioning

confidence: 99%

Chemical titration method for Determination of Concentration of REO in Rare Earth Fluoride Melts

Zhu¹,

Sun²,

Liu³

et al. 2017

Proceedings of the 2017 International Conference on Material Science, Energy and Environmental Engineering (MSEEE 2017)

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Abstract. In the present study, chemical titration method for determination of concentration of REO in REF 3 -LiF-RE 2 O 3 melts was investigated. The melts with the composition of 40mol%REF 3 -60mol%LiF (RE=La and Nd) was taken as object for illustrating the measurement of concentration and solubility of REO by the chemical titration method. Then the changing of REO concentration in 40mol%REF 3 -60mol%LiF melts with electrolytic time in practical electrolysis production was studied. The concentration of REO decreases with the electrolytic time, and rate of the decreasing also declines with the electrolytic time. And the reasonable time interval for REO addition was recommended defining as 1.75 h which is very close to the empirical value 2 h, This would also illustrate the reliability of chemical titration method on determination of concentration of REO in the melts.

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Oxide solubility and Raman spectra of NdF3–LiF–KF–MgF2–Nd2O3 melts

Cited by 60 publications

References 13 publications

Local Structure Analogy of Lanthanide Fluoride Molten Salts

Local Structure Analogy of Lanthanide Fluoride Molten Salts

Electrochemical Extraction of Rare Earth Metals in Molten Fluorides: Conversion of Rare Earth Oxides into Rare Earth Fluorides Using Fluoride Additives

Chemical titration method for Determination of Concentration of REO in Rare Earth Fluoride Melts

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