Biomass Utilization in Iron and Steelmaking

Iron and steel production is among the largest industrial sources of carbon dioxide, accounting for around 7–9 per cent of global emissions. Biomass offers a renewable pathway to replace fossil carbon in core processes such as blast furnace–basic oxygen furnace, direct reduction and electric arc furnace routes. Via thermochemical treatments—pyrolysis, torrefaction and gasification—lignocellulosic feedstocks are transformed into solid or gaseous reductants (biochar, torrefied pellets, biosyngas) that can partially or wholly substitute coal and coke. Integrating biomass not only reduces net CO₂ emissions but can also enable carbon‐negative steel when coupled with carbon capture and storage. Practical deployment hinges on sustainable feedstock supply chains, competition with other biomass applications, economic incentives and adaptation of existing plant infrastructure. Across diverse climates and resource endowments, techno‐economic assessments indicate substitution rates of 20–50 per cent can deliver meaningful emission cuts, while full decarbonisation may require novel alloying strategies and policy support to offset higher costs and logistical complexity.

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Biomass Utilization in Iron and Steelmaking publication trend

The graph below shows the total number of articles in biomass utilization in iron and steelmaking across all publications each year (not limited to Nature Index journals).

Technical terms

Biosyngas: A mixture of hydrogen, carbon monoxide and minor gases produced by gasification of biomass, used as a reductant in iron ore reduction processes.

Biochar: Carbon-rich solid obtained by slow pyrolysis of biomass, utilised as a partial substitute for coal and coke in metallurgical furnaces.

Direct Reduced Iron (DRI): Iron product formed by reducing iron ore with a gaseous or solid reductant at temperatures below melting, commonly used as feedstock in electric arc furnaces.

Electric Arc Furnace (EAF): Steelmaking unit that melts scrap or DRI using an electric arc; carbon injection is often required to control steel chemistry and slag foaming.

Torrefaction: Mild thermal treatment of biomass in an oxygen-limited environment to enhance energy density and grindability, yielding torrefied pellets suitable for metallurgical use.

References

1. Decarbonising the iron and steel industries: Production of carbon-negative direct reduced iron by using biosyngas. Energy Conversion and Management (2023).
2. Possibilities for CO2 emission reduction using biomass in European integrated steel plants. Biomass and Bioenergy (2018).
3. Review on the Use of Alternative Carbon Sources in EAF Steelmaking. Metals (2021).
4. Carbon capture and biomass in industry: A techno-economic analysis and comparison of negative emission options. Renewable and Sustainable Energy Reviews (2021).
5. Global assessment of biomass suitability for ironmaking – Opportunities for co-location of sustainable biomass, iron and steel production and supportive policies. Sustainable Energy Technologies and Assessments (2018).
6. To what extent could biochar replace coal and coke in steel industries?. Fuel (2023).
7. Reduced Carbon Consumption and CO2 Emission at the Blast Furnace by Use of Briquettes Containing Torrefied Sawdust. Journal of Sustainable Metallurgy (2019).