Structure evolution of blast furnace slag with high Al2O3 Content and 5 mass% TiO2 via molecular dynamics simulation and fourier transform infrared spectroscopy

The structure of a quenched blast furnace slag containing 5 mass% TiO2 was investigated via molecular dynamics simulation and Fourier transform infrared spectroscopy. The simulation and experimental results obtained revealed that the slag possesses a depolymerized network of [SiO4] and [AlO4] tetrahedra. At a fixed CaO/SiO2 mass fraction of 1.17 and 12 mass% Al2O3, increasing the amount of MgO decreased the bridging oxygen fraction in the slag system, thus resulting in silicate depolymerization. At a fixed CaO/SiO2 mass fraction of 1.17 and 8 mass% MgO, increasing Al2O3 content increased the bridging oxygen fraction because of the polymerization of aluminate structures. At a fixed 8 mass% MgO and 12 mass% Al2O3, increasing the CaO/SiO2 mass fraction from 1.07 to 1.50 decreased the bridging oxygen fraction because of the depolymerization of silicate and aluminate structures. Analyzing the slag structure via FT-IR spectroscopy verified these behaviors.