Low temperature alumina electrolysis.

摘要

A method of producing aluminium by electrolysis of alumina dissolved in molten cryolite at temperatures between 680-900°C is disclosed. The method comprises the employment of permanent anodes (2) the total surface of which is increased up to 5 times compared to the total surface of anodes in a classical Hall-Heroult cell of comparable production rate. By this means the anodic current density is lowered to a degree which permits the discharge of oxide ions preferentially to fluoride ions at an acceptable rate. Additionally, the electrolyte (4) is circulated by suitable means whereby it passes from an enrichment zone (8) where it is saturated which alumina to an electrolysis zone (1) and back.