The electrorefining of niobium has been investigated in LiCl-KCl eutectic melt with Nb3Cl8 at the temperature of 550°C by controlled potential electrolysis. The cathode deposits obtained at various cathode potentials were analyzed by XRD and EPMA. Tantalum content in deposits was measured by ICP. The cathode deposit was granular, powdery or dendritic niobium metal, and its morphology strongly depended on the cathode potential. Cathodic current efficiency was about 80% at the cathode potential of -0.8 to -1.2 Vvs. Ag/AgCl [(LiCl-KCl)eut.+ AgCl (5mol%)]. and it deteriorated above and below this potential range. The tantalum removal ability was affected obviously neither by the cathode potential nor by the tantalum content in the anode. The tantalum content in the cathode deposit was reduced to about a half of that in the anode. However, the tantalum removal ability in the chloride melt was inferior to that in the fluoride melt.
- Molten Salts
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