The mining giant and Lafarge Canada's Geocycle Canada business have over the last two years developed Alextra, an alternative raw material from which to make cement, and which is derived from potlining. 

Using Alextra as an alternative to alumina and silica as raw material, Lafarge Canada plans to initially produce 1 million tonnes of cement a year at its facilities in Bath in Ontario.

Rio Tinto and Lafarge Canada will explore expanding the supply of Alextra from Rio's potlining treatment plant in Saguenay-Lac-St Jean to Lafarge Canada's plants throughout the country.

Rio Tinto said it is the only primary aluminium producer in North America to process its potlining. Its treatment plant can process 80,000 tonnes of potlining per year.