Research on viscosities and structural characteristics of coal slags with various Al2O3 contents.

The corrosion of the alumina‐based refractory in coal slags would increase the Al2O3 contents of the coal slag and the influences of that on coal slag performances need to be further considered. The effects of Al2O3 on viscosities and structures of SiO2‐MgO‐CaO‐Fe2O3‐(10–22 wt%)Al2O3 coal slags were investigated in this work. The viscosity of the coal slag increased first with increasing the content of Al2O3 from 10 wt% to 14 wt% and further declined with the addition of Al2O3 content to 22 wt%. The role of Al2O3 in the present coal slag was identified. Al2O3 mainly behaved as an acidic oxide in coal slags when the Al2O3 content was less than 14 wt%, which polymerized the slag structure and increased the viscosities, and with further addition of Al2O3 to 22 wt%, a part of Al2O3 behaved as network modifiers due to the deficiency of enough metal cations for charge compensation, which could simplify the slag networks and reduce the viscosity. The variations of slag viscosities were consistent with the change tendencies of structures analyzed by spectra techniques. [ABSTRACT FROM AUTHOR]