Environmental data collection of new slag materials

The Fossil-Free Steel (FFS) initiative, which is supported by Business Finland, leads the way in shifting towards carbon-neutral steel manufacturing through the utilisation of environmentally friendly power and hydrogen. In line with Finland's objective to achieve carbon neutrality by 2035 and the European Union's goal of producing steel without fossil fuels by 2050, FFS plays a crucial role in decreasing CO₂ emissions.

This report explores the environmental data for new electric arc furnace slag (EAFS) from fossil-free steelmaking combining direct reduced iron and electric arc furnace (DRI-EAF) with emphasis on EAFS applications. Consequently, this report examines data needs and gaps. The purpose of the report is also to evaluate the system boundaries and allocation methods employed in the LCA literature regarding EAFS applications. These examinations support later stage life cycle assessment (LCA) studies and understanding of environmental impacts of utilizing the new slags.

The primary findings from literature review highlight the prevalent utilization of EAFS as aggregates, underscoring the necessity to explore a variety of applications through LCA. Especially, using EAFS as cement substitutes could provide high positive environmental impacts. This report also recognizes the scarcity of LCA studies specifically focused on EAFS derived from DRI-EAF process.

The literature review reveals that employing EAFS provides reductions in greenhouse gas (GHG) emissions especially through avoided landfilling and raw material production. However, the high density and absorption rate of EAFS may lead to disadvantages as well. While the reviewed literature indicates that the burden from steelmaking is generally not allocated to EAFS in LCA studies, the report identifies a need for establishing more uniform and transparent approaches when defining the system boundary and allocation methods. Ultimately, this report offers comprehensive analysis of environmental impacts associated with employing EAFS and the transition from blast furnaces to fossil-free processes in the slag production.