Thorium valency in molten alkali halides in equilibrium with metallic thorium

Smirnov, M.V.; Kudyakov, V. Ya.

doi:10.1016/0013-4686(83)85187-1

Cited by 10 publications

(6 citation statements)

References 8 publications

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“…Bing 21 proposed that Fe 3+ could be converted to Fe 2+ in KCl-CaCl is unstable in these eutectics. Reports thus far [20][21][22][23][24] suggest that the electrochemical method can be used to investigate the stable valence of electro-active species because the technique offers quick responses and in situ monitoring. The aim of the present work is to determine the stable valence state of Cr in FLINAK melts through CV and SWV.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical investigation of the stable chromium species in molten FLINAK

et al. 2015

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Section: Introductionmentioning

confidence: 99%

Electrochemical investigation of the stable chromium species in molten FLINAK

et al. 2015

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“…The subsequent investigations mainly focused on the equilibrium potentials of Th(IV) in molten chlorides, from which some thermodynamic parameters have been calculated. [10][11][12][13][14][15] And two different mechanisms with either two [10][11][12] or one [13][14][15] reduction steps have been proposed. The two step reduction involves the presence of Th(II) cations, whereas in the case of the one step reduction, the only stable valence state of thorium is Th(IV).…”

Section: Introductionmentioning

confidence: 99%

Extraction of thorium from LiCl–KCl molten salts by forming Al–Th alloys: a new pyrochemical method for the reprocessing of thorium-based spent fuels

et al. 2013

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“…Two different mechanisms were proposed based on the obtained results in molten chlorides. Smirnov et al 5 observed a two-step mechanism according to the reactions:…”

mentioning

confidence: 99%

Electrochemical and Microscopic Study of Thorium in a Molten Fluoride System

Straka

Szatmáry

Šubrt

2015

J. Electrochem. Soc.

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The electrochemistry of thorium in molten LiF-CaF 2 was examined on inert (Mo) and reactive (Ni) electrodes at 1173 K using cyclic voltammetry and chronopotentiometry. A single-step reduction mechanism was observed on the Mo electrode. Voltammetric results show signs of irreversibility. The diffusion coefficient of Th(IV) ions was calculated from the chronopotentiometric data. Deposition of metallic thorium was verified from the electrolytic experiment and subsequent XRD and SEM analyses. The formation of Th-Ni alloys was confirmed on the Ni electrode using cyclic voltammetry, open-circuit chronopotentiometry and SEM + EDS analysis of the deposit after a short electrolysis.Molten salts (fluorides or chlorides) were initially considered for nuclear energy production because of their advantageous physical and chemical properties: good heat transfer capacity, radiation insensitivity, high boiling point, and wide range solubility for actinides. In addition, it was realized that molten salts could be used in numerous situations: high-temperature heat transfer, core coolants with solid fuels, liquid fuel in a molten-salt reactor, solvents for spent nuclear solid fuel in the case of pyro-reprocessing and coolant, among others. 1 Among other applications, the electrochemical separation of actinides from lanthanides, 2 and molten salt/liquid metal extractions 3 are considered to be suitable methods for the reprocessing of spent nuclear fuel in the fuel cycles of future types of nuclear reactors. 2,4 Pyrochemical processes based on molten-salt systems (chlorides or fluorides) have significant advantages over aqueous processes (higher radiation stability, wide temperature range of usability, low process volume, etc.). The knowledge of actinide and lanthanide electrochemistry is necessary to develop pyrochemical separation methods. This paper aims to describe the basic electrochemical behavior of thorium in a molten-fluoride system (LiF-CaF 2 ), characterize the solidified melts with SEM + EDS and evaluate possibilities of electrolytic deposition of Thorium based on the obtained results. Inert (Mo) and reactive (Ni) electrodes were used.Untill now, several papers were published on the electrochemistry of Th in both molten chlorides and fluorides. Two different mechanisms were proposed based on the obtained results in molten chlorides. Smirnov et al. 5 observed a two-step mechanism according to the reactions:The one-step reduction of Th(IV) ions in chloride media according to Equation 3 was described in papers. 6-11In fluoride systems, Clayton et al., 12 Baes 13 and Chamelot et al. 4,14 observed the one-step reduction (Eq. 3) with four exchanged electrons. In, 4 it is stated that the electrolysis of Th on an inert electrode is a suitable method to separate thorium from lanthanides. ExperimentalChemicals and materials.-LiF and CaF 2 of commercial origin (purity 99.50% and 99.96% respectively) were dried in a vacuum dryer at 250 • C. The ThF 4 purity was verified with XRD analysis. The impurities were under the detection level ...

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Thorium valency in molten alkali halides in equilibrium with metallic thorium

Cited by 10 publications

References 8 publications

Electrochemical investigation of the stable chromium species in molten FLINAK

Electrochemical investigation of the stable chromium species in molten FLINAK

Extraction of thorium from LiCl–KCl molten salts by forming Al–Th alloys: a new pyrochemical method for the reprocessing of thorium-based spent fuels

Electrochemical and Microscopic Study of Thorium in a Molten Fluoride System

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