A decarbonized steel industry that includes carbon dioxide removal techniques in its net zero arsenal could use lower-grade iron ore, according to a new study by researchers from Heriot-Watt University in the UK.

Steel accounts for 5-8% of carbon dioxide emissions globally. Its total emissions have risen over the past decade, largely due to increased demand. The International Energy Agency has stated that, without innovation, the scope to limit emissions is ‘limited’. Therefore, the commercialization of new zero-emission production processes is critical tp achieving emissions reduction targets.

Such innovative processes are the focus of the new research from Heriot-Watt University’s Research Centre for Carbon Solutions, published in the Journal of Cleaner Production.

Reducing the emissions from steel production is essential in meeting climate targets while maintaining economic prosperity. Here we show that applying deep emissions mitigation to the steel industry together with the reaction of by-product slag with atmospheric carbon dioxide (CO₂) could result in a carbon negative industry on the order of up to a GtCO₂ yr^-1 by mid-century.

We used a bespoke technoeconomic assessment model that simulates a base-case scenarios in which steel is produced using a blast furnace and basic oxygen furnace. This system was augmented with a range of climate change intervention technologies including biomass based reducant, directly reduced iron, carbon capture and storage, and slag carbonation.

Surprisingly, strong incentivization ($200 – 500 tCO₂^-1) for emissions reduction and CO₂ removal from the atmosphere may create conditions under which lower grade ores are commercially viable and also achieve deep emissions mitigation. The additional costs for emissions reduction could be wholly offset by value generated through carbon removal from biomass energy carbon capture and storage together with slag carbonation.

—Renforth et al.

Resources

• Renforth, P., Campbell, J., Foteinis, S., Cosgun, E., Young, J., Strunge, T., Riley, A. L., Mayes, W. M., & Van der Spek, M. W. (2024). Carbon dioxide removal could result in the use of lower-grade iron ore in a decarbonized net-negative emission steel industry. Journal of Cleaner Production, 468, Article 142987. Advance online publication. doi: 10.1016/j.jclepro.2024.142987