[Abstract]

The iron and steelmaking industry is responsible for a significant share of global greenhouse gas (GHG) emissions and energy consumption. The more steel is produced, the more urgent the transition to decarbonization becomes. One alternative is the rotary hearth furnace (RHF), which produces direct reduced iron (DRI) from iron dust and then feeds it into an electric arc furnace (EAF). Compared to the Blast Furnace-Basic Oxygen Furnace (BF-BOF) route of conventional crude steel (CS) production, the integrated process reduces iron loss and GHG emissions. Life cycle assessment (LCA) is used to quantify the environmental impact of CS production processes. A mathematical model for major furnaces (BF, RHF, and EAF) was developed based on commercial operating data. This model-based approach enables a rigorous LCA of an integrated process. Three case studies analyzing the ratio of steel scrap, DRI, and hot metal fed into EAF in actual EAF operations were conducted. It revealed that integrating the BF-BOF route with the RHF-EAF route resulted in a reduction of approximately 1.91–1.94 million tonnes of CO2 eq. per year. We also conducted a scenario analysis of different electricity sources. Achieving further reductions would necessitate the utilization of nuclear or hydropower as renewable electricity sources, superseding solar or wind energy. The analysis can be used for the exploration of the policy implications and the decision making involved in the decarbonization of the steel sector.

DOI: https://doi.org/10.1016/j.jclepro.2025.146687

link: https://www.sciencedirect.com/science/article/pii/S0959652625020372