Abstract
Gallium is an increasingly important material in the fields of semiconductors and energy transfer. A prime source of gallium is the aluminate solution that remains after the purification of bauxite. The authors have sought a way of reclaiming gallium economically by electrolysis of a laboratory aluminate solution without having to use a cathode of mercury – an environmental pollutant. Cathodes of copper, indium, 70In–30Ga, Wood's alloy, and mercury (for comparison) were used with a wide range of anodes. The study accounted for the effects of electrode material, temperature, current density, and initial gallium concentration on the yield, energy consumption, and utilization of both current and electrode. The best results were obtained with indium or In–Ga cathodes and with platinum, Pt–Ti, or stainless steel anodes, at 75°C and a current density of ∼100 Am−2. Electrolysis was more efficient the higher the gallium concentration, demonstrating that commercial–scale electrolysis of aluminate solution is unlikely to be economically viable without prior concentration of gallium.
MST/305
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