Internal Carbon Cycles in the Steel Industry: Pathways for CO ₂ Management and Carbon Capture Utilization

ABSTRACT The steel industry contributes approx. 7%–9% to global CO 2 emissions and is therefore among the most emission‐intensive industrial sectors. Although hydrogen (H 2 ) based direct reduction offers a long‐term solution, transitional strategies are essential for existing assets. Internal carbon cycles describe the reuse and conversion of carbon‐containing by‐products within the steel plant and present a promising approach to circular economy. This article examines the mechanisms, technical feasibility, and environmental benefits of internal carbon loops and carbon capture utilization (CCU) integration, supported by recent research and industrial projects such as Carbon2Chem. Despite a growing body of CCU and steel decarbonization reviews, a consolidated discussion that starts from the realities of integrated‐plant gas and energy networks (availability, quality, and operational constraints) and translates them into actionable internal carbon‐cycle options remains limited. Therefore, this review provides an industrial practitioner perspective and proposes a structured classification of internal carbon cycles by gas stream, conversion step, and reintegration point in the steelworks to better distinguish near‐term retrofit pathways from longer‐term concepts.