CARBON FOOTPRINT IN THE STEEL INDUSTRY: HURDLES AND OPTIONS TO MITIGATE

Abstract

The iron and steel industry is one of the largest industrial sources of greenhouse-gas emissions because conventional ironmaking depends on carbon-intensive reduction chemistry and high-temperature energy. This paper reviews the carbon footprint of major steelmaking routes and evaluates practical and emerging mitigation pathways, with particular attention to carbon capture, utilization and storage (CCUS), top-gas recycling, hydrogen-based direct reduction, electric arc furnaces (EAFs), molten oxide electrolysis (MOE), circular scrap use, and membrane-based separation of blast-furnace gas (BFG). The manuscript consolidates route-level emission characteristics and discusses the trade-offs among energy demand, carbon intensity, technology readiness, infrastructure, and cost. Recent evidence indicates that BF–BOF remains the dominant route globally, while scrap-EAF and hydrogen-DRI-EAF can substantially reduce emissions when electricity and hydrogen are low-carbon. Membrane separation, particularly zeolite-based membranes, is identified as a promising modular option for CO2/H2 separation, although defect control, durability, gas pretreatment, scale-up, and economics remain major barriers. The review concludes that no single technology is sufficient: near-term reductions should combine efficiency, scrap optimization, process integration, and CCUS where appropriate, while long-term deep decarbonization requires abundant low-carbon electricity, hydrogen, and commercially mature alternative ironmaking.