Spent potlining: An update

Abstract

This paper continues of a review given in 1999 and resumes practices to treat the waste from used cathodes of the primary aluminium industry. The waste cathode lining consists of a carbon part and a refractory part. Spent potlining contains water-soluble fluorides and small amounts of leachable cyanides, and is therefore classified as hazardous. Besides inertization - such as treatment at high temperature, by vitrification, or by leaching and tlotation - the rerractory component can also be used for instance in the manufacture of cement, of concrete and brick, or as a road pavement additive, or and as a potIine electrolyte additive for the production of Al-Si pre-alloys. The carbon components can be used as a fuel additive in cement kilns, but also as an additive in the pig iron and steel industry. Various ways to treat and use spent potlining have been published in the meantime, and will be reviewed here.