Application of electrochemical techniques in pyrochemical processes – Electrochemical behaviour of rare earths at W, Cd, Bi and Al electrodes

Castrillejo, Y.; Bermejo, Raúl; Martínez, Ana María; Barrado, E.; Arocas, Paloma Díaz

doi:10.1016/j.jnucmat.2006.08.011

Cited by 79 publications

(50 citation statements)

References 22 publications

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“…Lanthanides-Al in LiCl-KCl [20]) usually show a succession of plateaus corresponding to the equilibrium between different intermetallic compounds, but it was not the case for the U-Al system. The second plateau at ∼ -1.00 V vs. AgCl/Ag can indeed not be resolved from the rest potential of the Al electrode in this melt.…”

Section: Open-circuit Potential (Ocp) Curvesmentioning

confidence: 99%

“…Open circuit chonopotentiometry technique was used in an attempt to identify the U-Al intermetallic compounds formed in LiCl-KCl and to determine their standard Gibbs energy of formation, as described for instance in [20,21]. After a short polarization, at a potential corresponding to the electrodeposition of U metal, the open circuit potential was recorded vs. time ( Figure 5) for T=450°C.…”

Section: Open-circuit Potential (Ocp) Curvesmentioning

confidence: 99%

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On the formation of U–Al alloys in the molten LiCl–KCl eutectic

Cassayre

Caravaca

Jardin³

et al. 2008

Journal of Nuclear Materials

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U-Al alloy formation has been studied in the temperature range of 400 -550 °C by electrochemical techniques in the molten LiCl-KCl eutectic. Cyclic voltammetry showed that underpotential reduction of U(III) onto solid Al occurs at a potential about 0.35 V more anodic than pure U deposition. Open circuit potential measurements, recorded after small depositions of U metal onto the Al electrode, did not allow the distinction between potentials associated with UAl x alloys and the Al rest potential, as they were found to be practically identical. As a consequence, a spontaneous chemical reaction between dissolved UCl 3 and Al is thermodynamically possible and was experimentally observed.Galvanostatic electrolyses were carried out both on Al rods and Al plates. Stable and dense U-Al deposits were obtained with high faradic yields, and the possibility to load the whole bulk of a thin Al plate was demonstrated. The analyses (by SEM-EDX and XRD) of the deposits indicated the formation of different intermetallic phases (UAl 2 , UAl 3 and UAl 4 ) depending on the experimental conditions.

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Section: Open-circuit Potential (Ocp) Curvesmentioning

confidence: 99%

Section: Open-circuit Potential (Ocp) Curvesmentioning

confidence: 99%

On the formation of U–Al alloys in the molten LiCl–KCl eutectic

Cassayre

Caravaca

Jardin³

et al. 2008

Journal of Nuclear Materials

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“…The so obtained curve (c) shows a pair of oxidation-reduction peaks, which can be attributed to the Nd(III)/Nd(0) reaction, assuming no reaction or very weak reaction between Li and Nd. This method has been widely used by many researchers [10,18,33]. Thus, the results show the reduction peak potential and the oxidation peak potential of curve (c) as -1.568 V and -1.328 V, respectively.…”

Section: Analysis Of Peak I Cmentioning

confidence: 97%

“…Also, there are six potential plateaus due to the dissociation of Nd in the Cd film into the salt, and the potential increases in the positive direction and the plateaus are formed sequentially. Many researchers have reported that this potential plateau in the CP experiment means is a two-phase region [21,33,[41][42][43][44]. According to the studies, when the compounds of the two different compositions coexist on the surface of the electrode, the activity of the metal element is maintained constant by the equilibrium until one compound completely changes to another compound, and thus, the electro motive force (EMF) remains constant [42].…”

Section: Electrochemical Reaction Of Ndcl 3 In Licl-kcl At Cd-coated mentioning

confidence: 99%

Electrode Reactions of Nd3+/Nd Couple in LiCl-KCl-NdCl3 Solutions at Solid W and Liquid Cd Electrodes

Sim

Kim²,

Paek

et al. 2018

International Journal of Electrochemical Science

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The behavior of Nd(III)/Nd(0) redox reaction at a solid tungsten (W) and liquid cadmium (Cd) electrodes in the LiCl-KCl-NdCl 3 system at 773 K was analyzed by using a cyclic voltammetry. The Nd(III)/Nd(0) reaction in the solid W electrode was found to occur in two steps through the process of Nd(II) ion generation. As the analytic results of the maximum current value according to scan rates in the region of 0.05 V/s to 0.3 V/s, the Nd(III)/Nd(II) reaction showed reversible reaction characteristics over the whole range, while the Nd (II)/Nd(0) reaction showed the reversible reaction in the region of 0.05 V/s to 0.2 V/s, as well as the quasi-reversible in the range of 0.2 V/s or higher. Furthermore, the diffusion coefficients of Nd(III) ion and Nd(II) ion were calculated by using the maximum current value, which were considerably consistent with the previous results of other researchers. The reduction potential of the Nd (III)/Nd(0) reaction in the liquid Cd electrode was measured as approximately 0.54 V higher than that of the solid W electrode because the reduced Nd formed an Nd-Cd intermetallic compound with a liquid Cd electrode, lowering the activity of Nd. To confirm this mechanism, experiments using Cd-coated W electrodes were conducted by using cyclic voltammetry and chronopotentiometry. The experimental results showed that 6 Nd-Cd intermetallic compounds were present. When the ratio of Cd is the highest, NdCd 11 is formed, and the potential in this case was very similar to the potential at the liquid Cd electrode. Furthermore, the Gibbs free energy and activity coefficient of Nd-Cd intermetallic compounds were calculated by analyzing the results of chronopotentiometry. The results could thermodynamically explain the potential difference of the Nd(III)/Nd(0) reactions occurring between the solid W electrode and the liquid Cd electrode.

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“…Так, эти вопросы, а также определение кинетических параметров электродных процессов в низкотем-пературном хлоридном расплаве LiCl-KCl и рас-плаве LiCl-CaCl 2 являются предметом изучения японских, испанских и российских ученых [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Электрохимическому получению сплавов интер-металлических соединений на основе празеоди-ма и неодима в галогенидных расплавах методом диффузионного насыщения посвящены работы [16][17][18].…”

Section: № 1 2014unclassified