An overview of biochar production techniques and application in iron and steel industries

Integrating innovation and environmental responsibility has become important in pursuing sustainable industrial practices in the contemporary world. These twin imperatives have stimulated research into developing methods that optimize industrial processes, enhancing efficiency and effectiveness while mitigating undesirable ecological impacts. This objective is exemplified by the emergence of biochar derived from the thermo-chemical transformation of biomass. This review examines biochar production methods and their potential applications across various aspects of the iron and steel industries (ISI). The technical, economic, and sustainable implications of integrating biochar into the ISI were explored. Slow pyrolysis and hydrothermal carbonization are the most efficient methods for higher biochar yield (25-90%). Biochar has several advantages- higher heating value (30-32 MJ/kg), more porosity (58.22%), and significantly larger surface area (113 m²/g) compared to coal and coke. However, the presence of biochar often reduces fluidity in a coal-biochar mixture. The findings highlighted that biochar production and implementation in ISI often come with higher costs, primarily due to the higher expense of substitute fuels compared to traditional fossil fuels. The economic viability and societal desirability of biochar are highly uncertain and vary significantly based on factors such as location, feedstock type, production scale, and biochar pricing, among others. Furthermore, biomass and biochar supply chain is another important factor which determines its large scale implementation. Despite these challenges, there are opportunities to reduce emissions from BF-BOF operations by utilizing biochar technologies. Overall, the present study explored integrating diverse biochar production methods into the ISI aiming to contribute to the ongoing research on sustainable manufacturing practices, underscoring their significance in shaping a more environmentally conscious future.