Influences of Zn, Fe and Cu Impurities on Electrorefining of Aluminum in BMIC-AlCl3 Ionic Liquid
杂质Zn,Fe和Cu对BMIC-AlCl3离子液体电解精炼铝的影响

The effects of Zn, Fe and Cu impurities on electrorefining of aluminum in 1:2 molar ratio BMIC-AlCl3 ionic liquid were investigated. The results showed that the potentials of Zn(II)/Zn, Fe(II)/Fe and Cu(I)/Cu were 0.21, 0.63 and 0.64 V vs. Al(III)/Al, respectively, which were much smaller than those in aqueous solutions. Constant current electrorefining experiments at 80℃ and 100 A/m2 current density indicated that the Zn, Fe and Cu in Al alloy anodes were removed almost. With increasing of Zn, Fe and Cu concentrations in anodes, their content in the Al deposit increased, but the depletion factor decreased, and the current efficiency was kept above 94%, and the energy consumption was between 1.59 and 1.74 kW·h/kg. The Al deposit with the purity higher than 99.8% obtained at cathode was dense and compact via electrolysis of aluminum alloy with 75.3%(ω) Al.