Anodic Dissolution of Al–Fe and Al-Fe-Si Alloys in Emimcl–AlCl₃ Electrolyte

To produce over 99.9% of high-purity Al from Al–Fe alloy containing Al6Fe and Al–Fe–Si alloy containing β-AlFeSi by electrorefining, their anodic dissolution and cathodic electrodeposition characteristics were investigated in an EmImCl–AlCl 3 ionic liquid electrolyte at 323 K. Constant potential electrolysis showed that Fe dissolved from Al–Fe anode at 0.7 V vs Al/Al(III) and from Al–Fe–Si anode at 1.4 V, and was co-deposited with Al on the cathode. Notably, anodic dissolution potential of Fe was changed by forming β-AlFeSi, and Si did not dissolve from β-AlFeSi at either potential. A combination of controlled anodic dissolution potential and the use of the Al alloy containing β-AlFeSi further suppressed the dissolution and cathodic co-deposition of Fe, affording high-purity Al on the cathode.