Viscosity of PbO-SiO2 melts

Viscosities (eta) of PbO-SiO2 melts that contained 25.0 to 48.8 mole pct SiO2 were measured at temperatures 928 to 1273 K by a rotating cylinder method. The data were analyzed in terms of the conventional polymer theory. The results followed Arrhenius behavior in the different temperature ranges despite the general belief of non-Arrhenius behavior of viscosity in slag melts. The calculated activation energies were a function of temperature and composition of the melts. The activation energies for viscous flow, in general, at above approximately 850 degrees C were lower than those below 850 degrees C and varied between 25 and 150 kJ per mole.