SPL: An update

Abstract

This paper continues a review given in 2012, and summarizes processes to treat the waste from used cathodes of the primary aluminium industry. Spent potlining (SPL) contains water-soluble fluorides and cyanides, and so is a hazardous waste which cannot be safely left in landfills. Ways have to be found to reuse this potline waste and to eliminate landfilling these carbon rich (– cut I-SPL) and refractory-rich (– cut II-SPL) cathode parts. Besides inertization, the refractory-rich part can be used as a valuable additive in the cement industry, in producing ceramic tiles, in lime kilns, as road pavement additive or as potline electrolyte additive. After floatation, the carbon rich cut I can be used as carbon-containing concentrate in the production of cathode blocks, in ramming pastes, as well as in raw material for prebaked anode manufacture. Furthermore the carbon-rich part can serve as fuel for the manufacture of cement clinker or in energy generation, can help in the recovery of fluorides such as AlF3, or can be used in the manufacture of rock wool, in selective steel manufacture, or in the pig iron industry.