Chemical assessment of the electric arc furnace slag as construction material: Expansive compounds

To carry out a correct management of electric arc furnace slags (EAS) requires a detailed knowledge of their properties. From a chemical point of view, the EAS are surrounded by some chemical problems related to its volume instability when they are used as construction materials, due to the presence of potentially expansive compounds such as free lime and mainly free MgO. The current work focuses on the chemical assessment of the black slags coming from an electric arc furnace in order to know the possible chemical disadvantages as construction materials. A complete study of chemical and mineralogical compositions, pozzolanic activity and the quantification of main expansive compounds in EAS were realised. The results show that the nature of these slags has a very high crystallinity; total absence of pozzolanic activity and the presence of expansive compounds in slags (Cl −, SO 3, free CaO and free MgO) were very low, if not null concentrations.