Neodymium electrowinning into copper-neodymium alloys by mixed oxide reduction in molten fluoride media

Mihaela Raluca Ciumag (1, 2) , Mathieu Gibilaro (1) , Laurent Massot (1) , Richard Laucournet (2) , Pierre Chamelot (1)

1 LGC - Laboratoire de Génie Chimique
2 Commissariat à l'Energie Atomique et aux énergies alternatives - CEA (FRANCE)

The possibility of neodymium electrowinning from neodymium oxide using a reducing agent (RA) produced in-situ by solvent reduction was investigated in molten LiF⿿CaF2⿿Li2O between 900 °C and 1040 °C. Nd2O3 galvanostatic electrolyses were performed and reaction products were analyzed by SEM, XRD and electron-probe microscopy. Metallic neodymium was not directly obtained, due to several limitations for Nd2O3 reduction: low electrical conductivity, unfavourable Pilling⿿Bedworth coefficient and formation of a dense insulating CaO layer on the sample surface. Consequently, the reduction of a pellet made of a neodymium oxide-metallic oxide mixture was carried out as an alternative pathway. Nd2O3-CuO reduction led to metallic neodymium production in the form of liquid Cu-Nd alloys. A reaction mechanism was proposed based on these experimental results:

Mots clés: Neodymium oxide; Electrochemical reduction; Molten fluoride; Copper-neodymium alloy

Domaines: Génie chimique; Génie des procédés

Mihaela Raluca Ciumag, Mathieu Gibilaro, Laurent Massot, Richard Laucournet, Pierre Chamelot. Neodymium electrowinning into copper-neodymium alloys by mixed oxide reduction in molten fluoride media. Journal of Fluorine Chemistry, 2016, 184, pp.1-7. ⟨10.1016/j.jfluchem.2016.02.001⟩. ⟨hal-01890092⟩