Environmental Assessment of Eaf slag in different "end of 2nd life"
Metallurgical industries produce a lot of steel slag. Their recycling allows reducing waste storage or landfilling, saving non renewable natural resources and promoting local economy. This paper presents the study of the environmental assessment of EAF slag (electric arc furnace slag) landfilling or recycling using life cycle assessment (LCA) in different “end of second life” scenario. In the LCA framework, the environmental assessment of recycling waste materials is taken into account only through waste processing. The phases of life cycle corresponding to stockpiling and use are in general considered to have no impact counted in LCAs. Therefore, the process of EAF slag production for recycling purposes was firstly investigated. Then life cycle assessment of landfilling and recycling is studied. Finally, the results for each use were compared to those obtained for natural sand. For the scenario “recycling”, technical characterization of the EAF slag was performed to verify its conformity to French standards and rules for use as road material. So, leaching tests were done, as the main property considered for recycling/landfilling waste materials, in France, is their potential emission of pollutants to water. All collected experimental data are then gathered together with generic data on sand LCA, landfilling LCA and transport LCA in order to compare the various impacts obtained for each step of the EAF slag life cycle and discuss the interest of various solutions considering both toxicity and ecotoxicity indicators.
Index terms- EAF steel slag, LCA, valorization, recycling