Spent potlining utilisation possibilities.

As the world's capacity for aluminium production increases, the amount of waste connected with this industry is also increasing. Spent potlining (SPL) from aluminium reduction cell cathodes presents a major environmental concern in the primary aluminium industry. It is concluded, after laboratory tests, that leachable cyanide and fluoride compounds present the major problem in SPL disposal. The behaviour of cyanide and fluoride under high temperature treatment has been investigated. On the basis of this laboratory investigation, the possibilities for SPL utilisation in red brick manufacturing, cement industry and thermal power stations were evaluated. SPL refractory material is already re-used in red brick manufacturing. In the cement industry, a pilot test on the utilisation of 25 t SPL carbon waste mixed with green petrol coke gave positive results. Additionally a fluoride emission forecast for a thermal power station utilising carbon waste SPL mixed with coal was elaborated.