BATH CHEMISTRY AND ALUMINUM CELL PERFORMANCE - FACTS, FICTIONS, AND DOUBTS

This article examines the relationship between bath chemistry and alum inum cell performance together with facts, fictions, and doubts arisin g from data available in the literature. An earlier trend toward more low-ratio baths now appears to have stopped at about 12% AlF3, which i s a typical bath composition used in modern, high-amperage cells. Wide ly different bath compositions are still used in older cells. Current controversies concern the effect of the alumina content in the bath on current efficiency and energy consumption, the true effect of LiF-con taining modified baths, and the optimum content of AlF3. Recent curren t efficiency data for lithium-modified low-ratio baths are discussed, together with the expected future development of bath chemistry in alu minum electrolysis cells. Further changes in bath composition can cont ribute to small, but significant improvements in cell performance, eve n in the best modern cells.