The kinetics of silica reduction in hydrogen

The kinetics of the reduction of SiO2 in hydrogen have been examined using a thermalgravimetric method. The mechanism of the reaction SiO2 + H2 = SiO + H2O can be described on the basis of a reaction interface moving at a constant velocity toward the center of the reacting sample. The velocity of the moving interface depends on the reaction temperature and water vapor content of the ambient gas. The reaction was studied in the temperature range 1115–1630°C and was found to be isokinetic in this range. The activation energy for the reaction is 85 kcal/mole in pure, dry hydrogen and 135 kcal/mole in hydrogen with a dew point of 24°C.