The reaction between finely divided SiO2 and SiC at 1270–1430°C was studied. The reaction scheme proposed is: 2SiC+SiO2= 3Sia+2COa 2Sia+CO = SiOa+SiC Sia+SiO2= 2SiOa Sia, SiOa, COa= Sig, SiOg COg. During the first 2–6% of reaction, Si volatilizes; thereafter primarily SiO and CO volatilize. Only the upper layers of the charge contribute to the net forward reaction rate, hence the state of reactant subdivision is of secondary importance. An Arrhenius plot of the reaction in vacuo gives an apparent activation energy of 131–97 kcal/mole in the range 1270–1430°C. The rate-determining step is desorption of products from the SiC surface.