Phase equilibria of CaO-SiO₂-5wt.%MgO-30 wt.%Al₂O₃-TiO₂ system at 1400 °C and 1450 °C relevant to high Al₂O₃ Ti-bearing blast furnace slag system

Due to the important effect of Al₂O₃ addition to the phase change in Ti-bearing slag system, the phase equilibrium relationships were investigated for the CaO-SiO₂-5wt.%MgO-30 wt.%Al₂O₃-TiO₂ phase diagram system with high Al₂O₃ content. The equilibrium phases were experimentally determined at 1400 °C and 1450 °C using the high temperature equilibrium technique followed by X-Ray Fluoroscopy (XRF), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscope (EDX) analysis. The gehlenite phase (2CaO·Al₂O₃·SiO₂), perovskite phase (CaO·TiO₂), spinel phase (MgO·Al₂O₃), Ti-rich diopside solid solution phase and anosovite solid solution phase were found. Based on the experimental results, the 1400 °C and 1450 °C isotherms and phase relations were obtained for CaO-SiO₂-5wt.%MgO-30 wt.%Al₂O₃-TiO₂ system relevant to high Al₂O₃ Ti-bearing slag system. - Highlights: • Phase diagram of CaO-SiO₂-5wt.%MgO-30 wt. %Al₂O₃-TiO₂ system is established. • The equilibria phase of 2CaO·Al₂O₃·SiO₂, CaO·TiO₂, MgO·Al₂O₃, Ti-rich diopside and anosovite are found at 1400 °C. • The equilibria phase of 2CaO·Al₂O₃·SiO₂ and MgO·Al₂O₃ are found at 1450 °C. • Liquidus lines were constructed at 1400 °C and 1450 °C, respectively.