Electrodeposition of Zr on graphite in molten fluorides

The electrochemical behavior of Zr4+ using graphite working electrode has been studied in fused LiF–NaF–ZrF4 eutectic mixture (temperature range 923–1123 K). In addition to the electrochemical profile related to the deposition/dissolution of Zr metal, the cyclic voltammograms exhibit well-defined peaks attributed to the formation of zirconium carbide. A third contribution relative to the formation of Li–graphite intercalation compound and/or lithium carbide was also proposed for a better interpretation of the voltammogram. Depending on the experimental deposition conditions, the analysis of the deposits by SEM/EDX has revealed the presence of a Zr metal thin film with various porosities and compositions. Moreover, the electrochemical reduction of Zr(IV) in molten fluorides using a graphite electrode allows the extraction of pure Zr metal.

Formation of Zr metal in molten fluorides.Figure optionsDownload as PowerPoint slideHighlights
► We studied the electrochemical reduction mechanism of Zr(IV) in fused LiF–NaF–ZrF4.
► The working electrode was a graphite rod.
► In such experimental conditions, the extraction of pure Zr metal is effective.