Towards carbon net zero steelmaking 2050

Steel production is responsible for approximately 8% of global CO₂ emissions. Roughly 80% of those emissions are the consequence of fossil-based reductants and fuel consumption in the production of steel via the primary steelmaking route starting from iron ores [1-3]. ArcelorMittal declared clear targets for CO₂ mitigation of steel production: 1) 35% CO2e emissions intensity reduction in Europe by 2030 and 2) the complete transition to net zero by 2050 at group level [4].

Hydrogen-Based Reduction: A Key Solution with Challenges

Hydrogen-based reduction of iron oxide is considered as a viable alternative to reduce fossil CO₂ emissions in steel industry. However, to counteract global warming, decarbonization of the steel sector must proceed much faster than the ongoing transition in industry, which is slowed down by an insufficient supply of green hydrogen as a particular bottleneck. The decarbonization roadmap of ArcelorMittal takes into account this challenge and therefore features five levers that act as steppingstones to achieve carbon-neutrality by 2050. These levers are:

• Steelmaking transformation
• Energy transformation
• Increased use of scrap
• Sourcing clean electricity
• Offsetting of residual emissions [4].

Technological Progress and Demonstration Projects

Technology progress on this road is encouraging, and numerous projects have been launched within ArcelorMittal. Examples are the projects in ArcelorMittal Ghent: Torero [5] and Carbalyst [6]. These demonstration units have been commissioned in 2023 & 2024, respectively. Both processes help to lower the CO₂ footprint of existent steelmaking processes. In the TORERO unit, waste wood is transformed via torrefaction to a biocoal, which then effectively replaces a part of fossil coal as reductant in the blast furnace. This approach uses carbon-based energy that does not add carbon to the biosphere, as regrowth of managed forests and crops will recapture the CO₂ emitted from the bioenergy used. The Carbalyst plant, allows to use carbon from steelmaking waste gases for the production of basic chemicals such as bio-ethanol, which are the key building blocks of plastics. These projects are examples for ongoing progress to reach carbon net zero steelmaking. Other initiatives, including the breakthrough Volteron™ plant [7] that targets iron metal production via electrolysis, are being launched and will further decrease the fossil footprint of steel industry.

H2Steel: Advancing Circular Economy and Hydrogen Integration

The H₂Steel concept is well aligned with the incremental strategy of ArcelorMittal. The concept improves circular economy by transforming biogenic waste streams to valuable biochar and upgrading of bio-methane to a clean hydrogen source. In addition, these products might be used in a flexible manner as biochar & hydrogen might be used as fossil coal replacement in several steelmaking processes, i.e. blast furnace and EAF. In parallel, the production of hydrogen contributes to partially debottleneck the shortage of the reductant. Further, it represents an alternative to the current production route of hydrogen, which relies heavily on fossil fuels. Considering these clear advantages of the technology concept, H2Steel could potentially represent a favorable step in the road to carbon net zero of steel industry.