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

Abstract

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.

Electrodeposition of metals from non-aqueous solutions

“…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 of the deposits indicated the formation of different intermetallic phases (UAl 2 , UAl 3 and UAl 4 ), depending on the experimental conditions [152].…”

Chemical and Electrochemical Extraction of Ytterbium from Molten Chlorides in Pyrochemical Processes

“…The most developed pyrochemical techniques have been electrorefining, electroextraction with reactive cath-odes, liquid-liquid metal reductive extraction and oxide precipitation, [10][11][12][13][14]. Although fuels proposed for transmutation tolerate small contents of FPs, most of them have to be removed.…”

“…Special attention must be paid to the Lns not only for their chemical similarity with the Ans, but also because of their neutronic poisoning properties. In spent nuclear fuels, the Lns contents might be up to 50 times that of Am/Cm [10]. On the other hand, during the electrochemical separation process the Lns accumulate in the solvent; this fact can modify the characteristics of the electrolyte and contaminate the final cathodic product.…”

Aluminum assisted electrodeposition of europium in LiCl–KCl molten salt

“…In order to reach a better understanding and control of these metal deposition processes, accurate knowledge of the electrochemical deposition mechanism is essential. Therefore, electrochemical studies of actinides (An) and lanthanides (Ln) in various molten salts have been carried out in the past decade [4][5][6][7][8][9][10]. However, electrochemical studies of the molten salt systems encounter many difficulties due to problems happened in electrodeposition of some Ans or Lns.…”

“…Recently Al has attracted considerable interest as an alternative working electrode or electrolyte material for electrodeposition of Lns or Ans [6][7][8][9][10]. It is well-known that, if an Al electrode is introduced into an electrochemical cell as a working electrode, the reduction of Eu 2+ occurs at potentials more positive than those of Li + and thus Eu can be deposited onto the working electrode [9].…”