Quantitative analysis of carbon footprints and mitigation potential in sustainable electric arc furnace steelmaking routes: A life cycle assessment perspective

Abstract

The electric arc furnace (EAF) steelmaking route offers a promising pathway for decarbonizing the iron and steel industry (ISI). However, the material-energy consumption and carbon emissions vary significantly depending on the metal charge structure, which complicates carbon accounting and weakens the effectiveness of low-carbon technologies. In this paper, from the life cycle assessment (LCA) perspective, the EAF steelmaking processes under the mixed metal charges of scrap, hot metal (HM), and direct reduced iron (DRI) are concentrated, and the corresponding LCA models and inventories are developed. The life cycle carbon footprints (LCCFs) of four typical scenarios (scrap+HM, DRI+scrap, HM+DRI, HM+scrap+DRI) are quantitatively analyzed and verified. The results reveals the LCCFs of the four scenarios are 439.6–1936.8, 636.7–1484.1, 1656.0–2165.1, and 1006.0–1798.1 kg CO₂, respectively. Among them, HM, DRI and electricity are consistently the major contributors to LCCFs. The scrap has the most significant LCCF reduction effect (77.3 %), followed by DRI (31.5 %). Furthermore, the total CO₂ mitigation potential of China`s ISI during 2020–2060 is predicted through the research results and future steel demand. The findings suggested that reducing the steel production and changing the production structure can both reduce the ISI CO₂ emission, and the largest CO₂ mitigation potential is 62.0 % during 2020–2060. When the ISI is integrated with decarbonization technology (carbon capture, utilization and storage (CCUS), and hydrogen-based DRI), the maximum CO₂ emissions can be reduced from 1850.0 to 484.1 million tons, achieving a maximum emission reduction effect of 73.8 % in the sustainable development scenario. Based on the LCCFs of metallurgical process sub-units and material-energy consumption items, several targeted carbon reduction measures are proposed. To achieve the long-term carbon neutral goal with the CO₂ mitigation potential of above 95 %, more efforts should be focus on innovations of resource-energy structure adjustment and efficiency improvement, smelting process optimization and breakthrough, and large-scale CCUS deployment.