Carbon footprint characteristics and reduction strategies of the iron and steel industry: an LCA-based study of source, process, end-use and cleaner production applications.

As global warming intensifies, the low-carbon transformation of the iron and steel industry becomes crucial for achieving "dual carbon" goals. This study provided a systematic review of the carbon footprint calculation methods for the iron and steel industry based on life cycle assessment (LCA) principles and demonstrates the application of LCA in the source, process, end-use, as well as in cleaner production stages of steel production through specific cases. Results indicated that raw material acquisition contributed 3.9-8.8 % of carbon emissions (primarily from electricity consumption) throughout the entire life cycle of steel production. The blast furnace process dominated (75.0-82.1 % of carbon emissions) in basic oxygen furnace routes, while carbon emissions of electric arc furnace routes were primarily influenced by the electricity consumption intensity of the electric furnace. In the construction sector, carbon emission intensity of steel products was lower than that of wood when the recycling rate of scrap steel exceeded 70.0 %. While aluminum alloys used in car doors had lower life cycle carbon emissions than steel due to their lightweight properties. Cleaner production technologies, such as carbon dioxide capture and storage (CCS), sensible heat recovery from blast furnace, and slag reuse, demonstrated significant carbon emission reduction potential, providing critical support for the industry's green transition.