Electrochemical behavior of neodymium in molten chloride salts

L. Diaz (1) , J. Serp (1) , Pierre Chamelot (2) , Mathieu Gibilaro (2) , Laurent Massot (2)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
2 LGC - Laboratoire de Génie Chimique

The discovery of NdFeB permanent magnets helps to perform technologies with reduced weight and gives them access to miniaturization. The industrial process of production of the Nd-Fe alloy by electrolysis used to manufacture of NdFeB magnets consists in reducing Nd$^{3+}$ ions dissolved in a LiF-NdF$_3$-N$_2$O$_3$ salt on iron cathode at 1050 DC. This route was chosen since the electroplating of neodymium at low temperature molten chloride leads to low recovery yields. This is usually attributed to the comproportionation reaction between the electrodeposited metal and its chloride salt (NdCl$_3$) leading to the formation of NdCl$_2$.In this work, the neodymium electrochemical behavior is reviewed in order to understand its reduction mechanism. Meal addition to LiCl-KCl-NdCl$_3$ melt is usually used to simulated comproportionation reaction in solution. Neodymium deposition yields are studied. Stability of Nd$^{2+}$ in two different solvent (LiCl-KCl and LiCl) is also discussed through electrodeposition tests on the gram scale.

Mots clés: Rare earth; Comproportionation reaction; Reduction; Molten chloride; Neodymium

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Physique Nucléaire Théorique [nucl-th]

L. Diaz, J. Serp, Pierre Chamelot, Mathieu Gibilaro, Laurent Massot. Electrochemical behavior of neodymium in molten chloride salts. TMS2017 - Annual Meeting and Exhibition, Feb 2017, San Diego, United States. ⟨cea-02437084⟩