Geocycle Canada, a Lafarge Canada subsidiary, and Rio Tinto have developed a new product called Alextra, made from used potlining*, as part of the aluminium electrolysis process that would otherwise go to landfill.
Alextra is made from used potlining – an essential part of the electrolysis process, where alumina is turned into aluminium. But for the process to work, potlining needs to be replaced every 5-8 years and the old lining contains hazardous materials, which need to be carefully managed.
Following years of work by our R&D team, in 2008 we set up a treatment plant in Quebec, Canada, that removes the hazardous substances from the used potlining and creates a safe material.
Alextra enables creating a building product from waste from aluminium production.
Lafarge Canada will produce on average one million tonnes of cement a year at its facilities in Bath, Ontario, using Alextra as an alternative to raw materials such as alumina and silica, which are commonly refined or mined for use in the manufacturing of cement.
The companies will explore options to further expand the supply of Alextra from Rio Tinto’s Potlining Treatment Plant in Saguenay-Lac-St Jean to Lafarge Canada's network of cement plants.
source ; Rio Tinto
*Spent Potlining (SPL) is a waste material generated in the primary aluminium smelting industry. Spent Potlining is also known as Spent Potliner and Spent Cell Liner.
Primary aluminium smelting is the process of extracting aluminium metal from aluminium oxide (also known as alumina). The process takes place in electrolytic cells that are known as pots.. SPL generates hazardous waste with properties such as:
Toxic fluoride and cyanide compounds that are leachable in water
Corrosive - exhibiting high pH due to alkali metals and oxides
Reactive with water - producing inflammable, toxic and explosive gases
source ; Wikipedia
Power in Numbers
Annual Production (Mt)