The viscosities of various FeO-SiO2 slags were calculated using a previousl
y developed structural-based model. Using hole theory and the atomic pair m
odel, an expression was derived to relate the viscosity to temperature and
the fraction of the bridging oxygen in silicate melts. The deduced equation
was successfully applied to predict the viscosities of FeO-SiO2 slags in t
he composition range of 0.1 < X-SiO2 < 0.423 for several temperatures. The
calculated data agree well with the experimental viscosity data.