Silica refractory materials in glass furnace combustion chambers absorb alkali-oxides dependent on alkali vapour pressures, temperatures and silica quality. Consequently, silica partly converts into low viscous alkali-silicate phases, resulting in silica loss and reduced crown lifetime. Especially in oxygen-fired furnaces and at temperatures below 1470 deg C, silica attack by alkali components is likely to lead to refractory material losses in the order of a few inches per year. The material loss of silica crowns is experimentally investigated and modelled in this paper. A model based on thermodynamics and mass transfer relations, is described. Some modelling results showing the effect of silica quality, temperature, gas velocity and sodium vapour pressure on silica loss rates are presented.
