Journal of Nuclear Fuel Cycle and Waste Technology

Zr electrorefining is demonstrated herein using Zirlo tubes in a chloride-fluoride mixed molten salt in the presence of AlF₃. Cyclic voltammetry reveals a monotonic shift in the onset of metal reduction kinetics towards positive potential and an increase in intensity of the additional peaks associated with Zr-Al alloy formation with increasing AlF₃ concentration. Unlike the galvanostatic deposition mode, a radial plate-type Zr growth is evident at the top surface of the salt during Zr electrorefining at a constant potential of −1.2 V. The diameter of the plate-type Zr deposit gradually increases with increasing AlF₃ concentration. Scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDX) and X-ray photoelectron spectroscopy (XPS) analyses for the plate-type Zr deposit show that trace amount of Al is incorporated as Zr-Al alloys with different chemical compositions between the top and bottom surface of the deposit. Addition of AlF₃ is effective in lowering the residual salt content in the deposit and in improving the current efficiency for Zr recovery.

Keywords

Zirconium recovery,Electrorefining,Cladding hull,Molten salt,Zr-Al alloys