Electrolytic Preparation of Zirconium Metal from a Consumable Zirconium Oxycarbide Anode

A single-phase zirconium oxycarbide was successfully synthesized by carbothermal reduction route at 1600 °C for 8 hours under argon atmosphere using ZrO2 and graphite powder as raw materials (the molar ratio of ZrO2 to graphite is 1:2.6). Effects of temperature, reaction time and molar ratio of ZrO2 to graphite on zirconium oxycarbide preparation were also investigated. The microstructure and composition of the products were characterized by X-ray diffraction, scanning electron microscopy, energy spectroscopy X-ray and ONH analyzer. The hot-pressed single-phase zirconium oxycarbide has good stability in molten NaCl–KCl. Subsequently, anodic dissolution of zirconium oxycarbide and the reduction mechanism of the dissolved zirconium ion in molten NaCl–KCl were investigated by a series of electrochemical technologies. The results show that the zirconium ion species dissolved in molten NaCl–KCl is Zr(II). Zr(II) is transferred from the anode to the cathode in the molten salt and is reduced to zirconium metal. Potentiostatic electrolysis at − 2.9 V was carried out using ZrCxOy as anode. CO gas was detected in the exhaust gas during the electrolysis, which can be explained as the combination of C and O atoms in ZrCxOy. The cathode deposit was detected to be zirconium metal. The results show that zirconium oxycarbide was a suitable anode material for the electrolytic synthesis of zirconium metal.