A Comprehensive Review of Secondary Carbon Bio-Carriers for Application in Metallurgical Processes: Utilization of Torrefied Biomass in Steel Production

Lina Kieush, Johannes Rieger, Johannes Schenk, Carlo Brondi, Davide Rovelli, Thomas Echterhof, Filippo Cirilli, Christoph M. Thaler, Nils Jaeger, Delphine Snaet, Klaus Peters, Valentina Colla

Research output: Contribution to journalReview articlepeer-review


This review aims to show the significance of the use of secondary carbon bio-carriers for iron and steel production. The term ‘secondary carbon bio-carriers’ in this review paper refers to biomass, torrefied biomass, biochar, charcoal, or biocoke. The main focus is on torrefied biomass, which can act as a carbon source for partial or complete replacement of fossil fuel in various metallurgical processes. The material requirements for the use of secondary carbon bio-carriers in different metallurgical processes are systematized, and pathways for the use of secondary carbon bio-carriers in four main routes of steel production are described; namely, blast furnace/basic oxygen furnace (BF/BOF), melting of scrap in electric arc furnace (scrap/EAF), direct reduced iron/electric arc furnace (DRI/EAF), and smelting reduction/basic oxygen furnace (SR/BOF). In addition, there is also a focus on the use of secondary carbon bio-carriers in a submerged arc furnace (SAF) for ferroalloy production. The issue of using secondary carbon bio-carriers is specific and individual, depending on the chosen process. However, the most promising ways to use secondary carbon bio-carriers are determined in scrap/EAF, DRI/EAF, SR/BOF, and SAF. Finally, the main priority of future research is the establishment of optimal parameters, material quantities, and qualities for using secondary carbon bio-carriers in metallurgical processes.
Original languageEnglish
Article number2005
Number of pages38
Issue number12
Publication statusPublished - 23 Nov 2022

Bibliographical note

Funding Information:
The authors gratefully acknowledge the funding support of K1-MET GmbH, a metallurgical competence center. The research programme of the K1-MET competence center is supported by COMET (Competence Center for Excellent Technologies), the Austrian programme for competence centers. COMET is funded by the Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology, the Federal Ministry for Labour and Economy, the Federal States of Upper Austria, Tyrol, and Styria, as well as the Styrian Business Promotion Agency (SFG) and the Standortagentur Tyrol. Besides the public funding from COMET, the research is partially financed by scientific and industrial partners. Furthermore, Upper Austrian Research GmbH supports K1-MET. The authors are also grateful to the Reviewers for their insightful comments and efforts in improving the manuscript’s text.

Funding Information:
Another project entitled “Development of a Low CO Iron and Steelmaking Integrated Process Route for a Sustainable European Steel Industry” (LoCO2Fe, RFCS project, 2015–2018, grant agreement No. 654013) [] coordinated by Tata Steel Netherland Technology was focused on achieving a decrease in CO emissions by at least 35%. The object of this project was the HIsarna ironmaking technology, which can achieve the necessary reductions in emissions, allowing partial replacement of coal with biomass. Additionally, this technology minimizes the use of coal due to the maximum use of energy in the reactor by balancing the energy between different parts of the reactor. Moreover, when carbon capture and storage (CCS) are used along with HIsarna, CO emissions can be reduced by up to 80%. 2 2 2

Funding Information:
In terms of process, the integrated use of secondary carbon bio-carriers is an innovative approach that requires adapting already existing technologies used in metallurgical production. Within the EU steel sector, the use of secondary carbon bio-carriers represents one technological pathway to push the decarbonization of the iron and steelmaking processes to reach the climate goal of zero net emission steelmaking processes by 2050. The efforts to implement secondary carbon bio-carriers are strongly promoted by the Clean Steel Partnership (CSP), a public-private partnership comprising all relevant stakeholders from the EU steel sector and scientific experts related to the field. The CSP is coordinated by the European Steel Technology Platform (ESTEP) and supported by the European Steel Association EUROFER. A roadmap (Strategic Research and Innovation Agenda, SRIA) developed by the CSP considers secondary carbon bio-carriers as one important energy source on the way to a sustainable and decarbonized future steel industry. Based on the SRIA of the CSP, research initiatives (funded and non-funded) will be necessary in the future to increase the quantity and quality of secondary carbon bio-carriers for enhanced use in metallurgical processes.

Publisher Copyright:
© 2022 by the authors.


  • biocoke
  • biomass
  • ferroalloys
  • iron and steel industry
  • secondary carbon bio-carriers
  • torrefaction

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