Quantification of Hydraulic Phase Contained in a Basic Oxygen Furnace Slag

The aim of the work presented here was to quantify the mineralogical phases contained in a basic oxygen furnace slag (BOFS), and especially the hydraulic phases, so as to evaluate the reactivity of this material. The chemical and mineralogical characteristics of BOFS were analyzed. This slag was essentially composed of calcium, iron, silicon, and magnesium oxides contained in five main minerals: calcium silicate oxides ($\beta \text{-}{\mathrm{Ca}}_2{\mathrm{SiO}}_4$ and ${\mathrm{Ca}}_3{\mathrm{SiO}}_5$), a solid solution of calcium aluminum ferrite oxides (${\mathrm{Ca}}_2{\mathrm{Fe}}_{1.52}{\mathrm{Al}}_{0.48}{\mathrm{O}}_5$), a solid solution of magnesium iron oxides (MgO0.432FeO0.568), and free lime CaO. The Rietveld method was used to determine the amount of each mineral phase and led to the following mineralogical composition: $\beta \text{-}{\mathrm{Ca}}_2{\mathrm{SiO}}_4=32\%$, ${\mathrm{Ca}}_3{\mathrm{SiO}}_5=2\%$, ${\mathrm{Ca}}_2{\mathrm{Fe}}_{1.52}{\mathrm{Al}}_{0.48}{\mathrm{O}}_5=26\%$, ${\mathrm{MgO}}_{0.432}{\mathrm{FeO}}_{0.568}=22\%$, and $\mathrm{CaO}=18\%$. BOFS thus contained a significant amount of hydraulic phase (dicalcium silicate and free lime), which was confirmed by the study of its reactivity using a hydrated paste.