Can mining slag store CO₂ emissions?
Iron-rich mining slag as a potential CO₂ storage material
A Concordia-led study suggests that an iron-rich waste product from mining—iron-bearing slag—could help store carbon dioxide (CO₂) emissions.
The researchers focused on whether slag chemistry can support reactions that effectively lock CO₂ into more stable mineral forms. They examined the feasibility of using the abundant, low-value material that mining operations already produce, rather than relying on new, dedicated geological or industrial resources.
This matters because capturing and storing emissions is one of the core challenges in climate mitigation. Geological storage is often discussed as the default pathway, but there are limits in capacity, location, and cost. Mineralizing CO₂ using industrial residues is attractive because it could convert waste management and carbon storage into a single industrial loop.
Key implications highlighted by the study’s premise:
- Waste-to-storage concept: Instead of treating slag solely as an environmental byproduct, it could be repurposed for carbon management.
- Mineral stability goal: The central question is whether reactions between CO₂ and slag components can produce carbonates or other stable solids.
- Industrial scalability: Mining waste is produced continuously and in large volumes, which is important for any climate technology that needs scale.
The study examined the conditions and mechanisms that would determine whether the slag can actually capture and store CO₂ effectively. However, the story indicates the work is framed as a feasibility assessment—moving from chemistry and reaction potential toward practical deployment will likely require additional testing, including how consistent results are across different slag batches and operating environments.
If further validated, slag-based CO₂ storage could expand the toolkit for reducing net emissions by turning an existing material stream into a carbon sink.