Corrosion–erosion wear of refractory bricks in glass furnaces

This paper presents the failure analysis of alumina–zirconia–silica (AZS) refractory bricks located in the glass level in the tank of a furnace for melting glass, since is the region where there is greater wear respect to the base. The wear of the refractory was evaluated after 4 years of campaigning, under thermal and mechanical loading during the glass manufacture. The analysis by scanning electron microscopy shows high porosity and the presence of alkalis is also detected from the glass composition, being the phase alumina–zirconia–silica (AZS),the one that shows better resistance to erosion wear by displacement of the molten glass. The analysis yielded the following mechanisms of chemical wear, removal of the vitreous phase toward the surface of the sample due to the increase in temperature of the furnace, and therefore attack by vapors through the porosity caused by the exudation of the vitreous phase, as well as deterioration of the microstructure of the refractory due to the formation of cracks. Because it is considered as the main problem in these types of furnaces, the erosion wear is related to the flows of convection currents within the tank, this occurs at the level of the glass, as it is at this point, where it has concentration of thermal and mechanical loads due to movement of the molten glass.