Electrochemical Study of Zr from Anodic Dissolution using a Consumable Zirconium Nitride Anode

Zirconium nitride (ZrN) has proved to be a promising new catalyst material. Bearing in mind its recyclability at end-of-life, the objective of this work was to demonstrate recovery of Zr in an electrochemical process using a consumable ZrN anode. A mechanically stable ZrN anode was made from synthetic ZrN powder by spark plasma sintering. The anodic dissolution was carried out in an equimolar NaCl-KCl molten salt at 727 °C (1000 K) by potentiostatic polarization. Cyclic voltammetry of the molten salt was performed before and after the anodic dissolution. It was successfully demonstrated that Zr ions were dissolved into the molten salt. The electrochemical characterization of the electroactive species showed a two-step electrochemical process, related to the reduction steps Zr(IV)/Zr(II), and Zr(II)/Zr. Analysis of voltammograms showed diffusion controlled electrochemical reactions and the diffusion coefficients calculated correlated well with values reported in the literature.