Lafarge and TransAlta look to fly ash for concrete
By Adam FreillConcrete Construction Materials Green Construction
Companies to use waste product from former coal-fired electricity operations to advance low-carbon concrete for construction projects.
Lafarge Canada and TransAlta Corporation are going to repurpose landfilled fly ash to replace cement in concrete. The fly ash is a waste product from TransAlta’s Canadian coal-fired electricity operations west of Edmonton, which ended in 2021.
“Driving innovative and sustainable initiatives is a key part of our business in Alberta and across Western Canada,” said Brad Kohl, president and CEO of Lafarge Canada (West). “There is great potential in repurposing materials across the construction value chain. Transforming landfilled material, such as fly ash, into a usable product for construction, is a win-win solution for all of us.”
“Our role in this project demonstrates TransAlta’s commitment to supporting innovative solutions for our customers that reduce their environmental footprints and meet their ESG goals,” said Blain van Melle, executive vice-president, Alberta Business, at TransAlta Corporation. “Using fly ash to make concrete creates a valuable opportunity to recycle one of the largest waste streams in North America. It’s a great complement to the zero-emissions electricity we are currently providing to Lafarge from our wind platform in Alberta.”
Landfilled fly ash must first go through a beneficiation process to be used in concrete. The project will use Ash-TEK Ponded Ash Beneficiation System (PABS) technology, which has consistently produced high quality ash during trials and has a low-carbon footprint and an economical operating cost. Lafarge will deploy this unique approach to the process, removing moisture from the ash, milling it, and removing excess carbon, ensuring that it meets regulatory standards and market expectations.
Geocycle, a provider of sustainable waste management services worldwide, and Lafarge’s subsidiary in Canada, will also join the initiative. The organization brings experience in managing millions of tonnes of fly ash in the U.S.
“Landfilled fly ash sometimes has too much carbon, which affects how much air there is in the concrete. Once we can treat and separate that carbon, then the fly ash is ready to be used in place of cement,” commented Sophie Wu, Head of Geocycle, North America. The fly as can be used to replace up to 25 per cent of the cement, in a standard replacement, she explained.
Although the role of fly ash in concrete manufacturing isn’t new, the technology for beneficiation is highly exact and specialized.
“We recognize that seizing opportunities to optimize cement is a key part of our CO2 reduction strategy,” said Kohl. “Thinking outside the box is a part of how we do business.”
In November 2021, Lafarge Canada was awarded $15 million from the Government of Alberta through Emissions Reduction Alberta (ERA) to advance this project with TransAlta.