杂质Zn,Fe和Cu对BMIC-AlCl_3离子液体电解精炼铝的影响

Influences of Zn, Fe and Cu Impurities on Electrorefining of Aluminum in BMIC-AlCl_3 Ionic Liquid

研究了摩尔比为1:2的BMIC-AlCl3离子液体中杂质元素Zn,Fe和Cu对电解精炼铝的影响.结果表明,离子液体中Zn(II)/Zn,Fe(II)/Fe和Cu(I)/Cu相对于Al(III)/Al的平衡电极电势分别为0.21,0.63和0.64V,比其标准电极电势相对值小得多;在温度80℃和电流密度100A/m2条件下进行电解精炼,铝合金阳极中的绝大部分Zn,Fe和Cu杂质被去除,阴极铝沉积层中杂质含量随阳极杂质含量增加而升高,但杂质的贫化率降低,电流效率均超过94%,能耗为1.59～1.74kW·h/kg;电解精炼铝含量为75.3%(ω)工业铝合金得到了纯度超过99.8%的金属铝,且沉积层致密平整.

The effects of Zn, Fe and Cu impurities on electrorefining of aluminum in 1：2 molar ratio BMIC-A1Cl3 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）/A1, 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 AI alloy anodes were removed almost. With increasing of Zn, Fe and Cu concentrations in anodes, their content in the A1 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 A1 deposit with the purity higher than 99.8% obtained at cathode was dense and compact via electrolysis of aluminum alloy with 75.3%（ω） A1.