Influence of Al2O3 on viscous behavior and structure characteristic of TiO2-bearing molten slags

The influences of the increasing content of Al2O3 caused by refractory corrosion on the properties and structures of CaO–MgO-(15 wt%-27 wt%)Al2O3–SiO2–TiO2–FeO molten slags were studied at high temperature from 1923 K to 1798 K. The viscosity experimental results indicated that the slag viscosity first increased and then reduced with increasing the Al2O3 content in TiO2-bearing slags, and the Al2O3 content that reflected the inflection of the viscosity variation was about 21 wt%. From the Raman and NMR spectra analysis, when the Al2O3 content in the TiO2-containing slag was lower than 21 wt%, Al2O3 was an acidic oxide which could increase the viscosity, and with the Al2O3 content in slags further increased to 27 wt%, Al2O3 would behave as network modifiers to decrease the slag viscosity. From the XPS results, the amount of O2− decreased first and then raised, while the ratio of O0 and O− increased and then decreased with adding Al2O3 to slags. The changing trend of the oxygens had a good accordance with the variation of slag viscosities.