Agricultural waste emerges as a viable coal substitute in steelmaking
Researchers from CSIRO and the Indian Institute of Science (IISc) have successfully demonstrated a viable approach to reduce emissions from steelmaking by partially replacing coal with agricultural waste.The breakthrough offers a scalable pathway to commercial use and cutting emissions in one of the world’s fastest growing industrial economies, marking a major advance in efforts to decarbonise iron and steelmaking.Using locally sourced rice husk pellets, the CSIRO team validated sustained production of biomass-derived synthesis gas for iron ore reduction at a large-scale commercial steelworks in India.The trial was completed in partnership with commercial steel innovator RESCONS Solutions.India’s steel sector is the fastest-growing globally, projected to double its capacity to 300mt by 2030 and reach 500mt by 2047. This rapid expansion poses a major challenge for global emissions, with India’s steel production emitting an average of 2.55t of carbon dioxide per tonne of steel — well above the global average of 1.85-1.92t, according to World Steel.The sector is responsible for about 12% of India’s total emissions.To address these challenges, the Indian Ministry of Steel has outlined a roadmap to achieve net zero emissions by 2070, including strategies such as transitioning to electric arc furnaces, increasing scrap use, carbon capture and storage, green hydrogen and using biomass as a replacement for coal.Leveraging India’s abundant agricultural waste, the CSIRO-led team, with funding from the Federal Government’s India-Australia green steel research partnership, conducted a full-scale trial at Jindal Steel in Odisha. The team successfully blended 5% and 10% rice husk pellets into Jindal Steel gasifiers, achieving sustained syngas production with no loss of performance.CSIRO senior experimental scientist Warren Flentje says the trial is a world-first demonstration of how agricultural waste can be harnessed to decarbonise steelmaking at scale.“By blending rice husk pellets into commercial gasifiers, we’ve shown that biomass can replace coal without compromising performance,” he said.“This is a major step forward for sustainable steel production in India and globally.”If adopted across India, the process could reduce steel sector emissions by up to 50% totalling about 357mtpa of carbon dioxide.Building on this success, the team will expand their work to include smaller-scale regional steelmaking facilities and a wider range of biomass sources, including integrated systems that produce both food and steel feed.Jindal Steel executive director Damodar Mittal says the collaboration marks a pivotal moment in India’s journey towards decarbonisation.“By integrating green energy and biomass into our production processes, we are not only reducing our carbon footprint but also setting a new benchmark for the Indian steel industry,” he said.Air quality is a major health issue in India, with more than 30,000 deaths annually linked to poor air quality, with much of it caused by in-field burning of crop residues.This pioneering work by CSIRO and its Indian partners could fast-track the adoption of biomass for steelmaking, delivering major emissions reductions, improving air quality and supporting regional economic development in India.CSIRO green metals production research group leader Keith Vining says the trial has demonstrated that biomass can be a viable alternative to coal, especially in regional areas where surplus agri-waste and coal DRI facilities co-exist.“The next phase will focus on increasing biomass replacement rates and assessing impacts on the direct reduction process,” he said.
