Project Overview
The project was awarded funding in ACT4 and addressed the need for local and readily available Supplementary Cementitious Materials (SCMs). At project completion in 2025, Carbon Upcycling Technologies (Carbon Upcycling) successfully determined and characterized five locally sourced, low-value waste feedstocks that can be used as SCMs and will have the capacity to produce up to 30,000 tonnes of SCMs annually after the next stage of the project.
Testing Industrial Byproducts to Determine Suitability as Cement Product
SCMs are derived from industrial byproducts (like slag from steel making or fly ash from coal) and added to concrete to offset cement clinker, the most carbon-intensive ingredient in concrete. However, as Canada and Alberta move away from coal power plants and traditional steel production methods, the supply of common materials used as SCMs in cement is decreasing. The project addresses this problem by turning a local byproduct from steel production in Alberta and Canada into a cement replacement.
Carbon Upcycling’s patented Mechanically Assisted Chemical Exfoliation (MACE) process is a low-energy, ambient-temperature technique for converting various industrial feedstocks into carbonated SCMs by exposing them to CO2 of different purities. MACE enhances the surface area, porosity, and chemical activity of the materials, enabling the steel byproduct to bond with CO2 and permanently store it. The result is a low-carbon, durable alternative to clinker, reducing concrete’s carbon footprint by up to 30%. This innovation also keeps slags out of landfills, cuts down on waste, and strengthens local supply chains by reducing the need to import materials. By integrating CO2 capture into the cement-making process, this project offers a pathway to decarbonize one of the world’s most carbon-intensive industries.
This project evaluated the suitability of these SCMs as inputs in the MACE process and developed ideal processing conditions for the CO2 enhancement of these SCMs.
Steel Slag Feedstock to be Commercialized
Carbon Upcycling and the National Renewable Energy Laboratory (NREL) partnered to develop and demonstrate a framework to assess various SCMs available in North America, including byproducts from high-emitting industries, steel and mining, for their suitability as SCMs. The activities in the project increased understanding of suitable product identification for SCMs significantly.
Carbon Upcycling and NREL tested five materials as potential candidates for SCMs: basalt, mine tailings, waste glass, Electric Arc Furnace (EAF) slag, and Blast Oxygen Furnace (BOF) slag. The materials were chosen for analysis based on appropriate chemistry for carbonation and geographic availability. The highlights of the testing revealed that direct CO2 conversion of enhanced SCM by weight was the highest in EAF and BOF slags. EAF and BOF slags were chosen for concrete pours and TEA analysis because of positive initial testing, their ability to scale up from lab to commercial scale, and their ability to sequester CO2. Both had good strength and CO2 uptake and are readily available in Canada and the USA.
The steel byproducts, BOF and EAF slag, normally do not capture CO2, but Carbon Upcycling’s process “activates” it, allowing it to bond with CO2. Carbon Upcycling’s process captures CO2 and sequesters it into the slag. Partially replacing clinker with this CO2-enhanced material further reduces the carbon footprint of cement. The project advanced the knowledge of what novel SCM’s can be used in the cement and concrete industry in Alberta, Canada and the USA and demonstrated the potential of BOF slag as a sustainable alternative to traditional SCMs.
What’s next?
In another ERA-supported project, Carbon Upcycling is partnering with BURNCO and CRH to upcycle byproducts into SCMs, representing the first commercial-scale deployment of two carbon capture and SCM production facilities. Currently constructing a world’s first-of-a-kind pilot project in Mississauga, Ontario, to enhance slag from blast oxygen furnace (BOF) steel production identified in this project to produce up to 32,000 tonnes per annum of BOF slag SCM. The results of this project will be published in the ACI Journal. Ongoing work will be conducted to understand and validate the EAF slag, mine tailings, and basalt material testing for use as novel SCMs. Going forward, Carbon Upcycling is planning to test additional materials such as waste concrete and incinerator ash.