Reuse, remanufacturing and recycling in the steel sector

The global steel sector is undergoing a transition from being a major CO₂ emitter to a more sustainable circular material service provider, moving towards (near) net zero CO₂ through combined strategies of reuse, remanufacturing, recycling and changes to primary steelmaking. This paper considers the transition using the UK as an example, based on the current sector state and future plans/opportunities. Some key enablers/barriers have been identified, and case studies are presented on the current state of knowledge and technology developments. For example, increasing reuse/remanufacturing requires data on the component's remaining life at the end-of-product life; in this work use of in-service monitoring for steel-intensive applications in the transport sector is discussed identifying sensor types/locations for fatigue loading assessment for different use conditions to feed into material/product passports for reuse/remanufacturing decisions. Increased recycling of obsolete scrap has implications for composition control with increases in residual elements, such as Cu, Sn, Cr and Ni inevitable. Current and future approaches to recycling and scrap sorting are discussed along with case studies for how residual elements affect microstructural development during steel processing, including effects on recrystallization, phase transformation and fine-scale precipitation, which potentially could be exploited to give increases in product strength. This article is part of the discussion meeting issue 'Sustainable metals: science and systems'.