Effect of AlF3 on Zr Electrorefining Process in Chloride-Fluoride Mixed Salts for the Treatment of Cladding Hull Wastes

다국어 초록 (Multilingual Abstract)

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.

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