Spent pot lining is the most common waste product generated by an aluminum smelter. It consists of the carbon and refractory lining that cover the bottom and sides of the electrolytic pots, and is extracted at the end of a pot’s useful life. The quantity of spent pot lining produced depends on the number of pots relined, which varies from year to year according to the life cycle of the pots.
In 2011, the quantity of spent pot lining produced increased significantly because a greater number of pots were shut down for renovation.
In 2010, we implemented solutions to increase the recycling and valorization of the spent pot lining generated in Québec. Our efforts translated into a 90% recycling rate for that year. The carbon portion is sent to Germany to be valorized as a fuel source, while the refractory linings are recycled at cement plants in the United States, which use them as a mineralizer. Waste that cannot be recycled or valorized is sent to Alcoa’s plant in Gum Springs to be treated and disposed of. The recycling rate in 2011 was again around 90%.