Reshaping the circular material flow of electric arc furnace slags by valorization as supplementary cementitious materials

In the context of the emerging hydrogen-based primary steelmaking processes, the project aims to further the knowledge of electric arc furnace (EAF) slags to reshape the valorization route for use as supplementary cementitious materials (SCMs). In Sweden, annual EAF slag volumes are projected to reach 1.2 million tons by 2030.

Using this slag as an SCM would mitigate 1.0 million tons of carbon dioxide emissions from the cement industry, equal to 2.1 % of Sweden’s total emitted carbon dioxide equivalents in 2022. Furthermore, the quarrying of 1.3 million tons of calcite can be mitigated.

Presently, scrap-based EAF slags are primarily used in road construction, and previous studies have attempted the proposed valorization route as SCMs. However, all but three published papers have neglected the fundamental prerequisites for generating an SCM.

Considering these three studies, the research gap includes the requirements for slag handling, e.g., the need for modifications and/or reduction before granulation, as well as how elements attributed to the hydrogen direct-reduced iron affect the feasibility of realizing the valorization route.

These aspects will be addressed experimentally in the proposed project by a researcher with multiple years of experience researching by-products from the metallurgical industry in general and slags as SCMs in particular. The investigations are timely, aligning with the ongoing transition of the steel industry.