Study of neodymium extraction in molten fluorides by electrochemical co-reduction with aluminium
Résumé
This work describes the co-deposition process of Al–Nd alloys in LiF–CaF2 medium (79–21% mol) on
tungsten electrode at 860 C using electrochemical techniques: cyclic and square wave voltammetries
and potentiostatic electrolyses. Specific peaks of Al–Nd alloys formation were observed in cyclic voltammograms
between the reduction waves of Nd(III) and Al(III), in a fluoride melt containing neodymium
and aluminium ions. The potential difference measured between the solvent reduction and the alloys formation
should allow expecting an extraction efficiency of 99.99% by the use of the co-reduction process.
The intermetallic compounds (Al11Nd3, Al3
Nd, AlNd2 and AlNd3) were obtained and characterised by
Scanning Electron Microscopy with EDS probe. The validity of the process was tested by carrying neodymium
extraction in the form of Al–Nd alloy; the extraction efficiency was more than 95%.