The electrochemistry of gadolinium in the eutectic LiCl–KCl on W and Al electrodes

The mechanism of rare earth metals (Gd and Dy) chloride complexes electroreduction on the tungsten electrode in equimolar NaCl-KCl melt at 973 K has been studied by linear and cyclic voltammetry. Some kinetic parameters of processes were calculated. It was shown that the tungsten electrode was indifferent to gadolinium and dysprosium which were reduced on the surface. We found that the discharge mechanism of gadolinium and dysprosium chloride complexes was described by three-electron step when the steady-state conditions of polarization were limited by the mass transfer stage. The conditions of nonstationary polarization made the slowness of the charge transfer stage. The diffusion coefficient of gadolinium and dysprosium ions was calculated, the diffusion coefficient of ions was (0.9, and for ions, it was (1.60 ± 0.2) × 10 −5 сm 2 ·s DyCl −

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“…The diffusion coefficient of 6 ions is (0.9 ± 0.2) × 10 . These values were in good agreement with early published data [15][16][17].…”

Section: Cyclic Voltammograms At Different Return Potentials Presentesupporting

confidence: 93%

The Electroreduction of Gadolinium and Dysprosium Ions in Equimolar NaCl-KCl Melt

Kushkhov¹,

Uzdenova²,

Saleh³

et al. 2013

AJAC

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“…[35][36][37][38]44,48 The surface area of the working electrode was defined by changing the immersion depth of the working electrode by small controlled increments and measuring the transition time while keeping everything else constant (e.g., temperature, value of applied current). Plotting the square root of a transition time as a function of surface area of working electrode generates a linear plot from which the initial area of the electrode can be calculated.…”

mentioning

confidence: 99%

Method Development for Quantitative Analysis of Actinides in Molten Salts

Tylka

Willit

Prakash

et al. 2015

J. Electrochem. Soc.

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This paper describes how electrochemical techniques have been used to develop a method for high-precision, real-time quantitative measurements of the concentration of actinides, present in in molten salts as actinide chlorides, for pyrochemical process monitoring applications. Possible reasons for discrepancies between reported measurements obtained with electrochemical techniques have been investigated and a combination of methods to improve their precision has been established. The combination of methods consists of selecting a suitable electroanalytical measurement technique, experimentally verifying assumptions used in its theoretical analysis, ensuring reproducible conditions at the electrode/electrolyte interface, and using an improved method to eliminate the need to know the electrode surface area. By following the developed procedures and refining both experimental techniques and data analysis methods, precise and reproducible measurements were obtained for U and Pu in LiCl/KCl eutectic at 773 K. Preliminary results showed that cyclic voltammetry, along with a method of standard area addition, are very promising tools for in situ quantitative measurements with a degree of precision comparable to destructive analysis techniques. Electrorefining is the main step in pyrochemical reprocessing. During this process, actinides are separated from the bulk of the fission product elements by electrochemical dissolution and electrotransport onto a solid or liquid cathode. The goal of the process is to maximize the separation and recovery of actinides from chlorinated fission products so that minimal amounts of actinides are lost to the process waste stream. [1][2][3][4][5] In addition to efficient actinide recovery, there is a need to address the safeguarding the recycle system. 5 Highprecision, real-time concentration measurements of actinides, present as actinide chlorides, in molten salts are required for process monitoring and control and could be used to support traditional material control and accountability techniques. Development of these measurements is essential to implement and operate a commercial fuel reprocessing facility. [6][7][8][9][10] Electrochemical techniques are well suited for in situ monitoring because they allow rapid, real-time measurements, are compatible with remote handling operations, and do not require the use of standards. Also, the equipment is not affected by the high radiation field present in a fuel processing operation.9,10 Unlike offline destructive analysis techniques, in situ methods do not require representative sample collection and preparation, and therefore avoid problems with sample contamination and degradation. In addition, analytical results can be received in a relatively short period (for example, less than 2 minutes).In an electrochemical cell, the measured potential (E), current (i), or charge (Q) is related to the quantity of the analyte in the solution; therefore, it can serve as an analytical signal for concentration measurements. 11,12 Depending on the applied...

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“…The diffusion coefficient of Gd 3+ was estimated to be 0.68 © 10 ¹5 cm 2 s ¹1 at 723 K, which is close to the value in the literature. 28 This result emphasizes that the graphene electrode can also be used for the electrochemical measurements of lanthanide ions in LiCl-KCl melt.…”

Section: +mentioning

confidence: 80%

Electrochemical Reactions of Uranium Trichloride on a Graphene Surface in LiCl-KCl Molten Salt

et al. 2014

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The electrochemcal reactions of uranium trichloride on the surfaces of dimensionally very dissimilar carbon-based materials such as glassy carbon (GC) and graphene in LiCl-KCl eutectic melt were investigated using cyclic voltammetry (CV) and scanning electron microscopy (SEM). The cathodic scanning of CV displayed that the Li intercalation reaction into the GC electrode governs at the potential of approximately −1.45 V vs. Ag|Ag + where the electrodeposition reaction of uranium may occur. On the other hand, the graphene electrode presented electrodeposition current of the uranium without interference at −1.45 V vs. Ag|Ag + because the Li intercalation reaction was extensively diminished on the very thin graphene film. In addition, it was successful to measure the electrodeposition current of gadolinium at more positive than −2.1 V without the interference of the Li intercalation into the graphene substrate. Consequently, the significant reduction of the Li intercalation reaction on the nanometer thick carbon electrode extensively expands the electrochemical potential window of the carbon-based electrode with respect to the bulk carbon electrode in LiCl-KCl melt, emphasizing that the graphene has a great potential as a cathode electrode in high temperature molten salt electrolytes.

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The electrochemistry of gadolinium in the eutectic LiCl–KCl on W and Al electrodes

Cited by 118 publications

References 25 publications

The Electroreduction of Gadolinium and Dysprosium Ions in Equimolar NaCl-KCl Melt

The Electroreduction of Gadolinium and Dysprosium Ions in Equimolar NaCl-KCl Melt

Method Development for Quantitative Analysis of Actinides in Molten Salts

Electrochemical Reactions of Uranium Trichloride on a Graphene Surface in LiCl-KCl Molten Salt

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