THE SI-C-O SYSTEM .2. ISOBARIC EVOLUTION OF THE SYSTEM

In a reactor where the pressure is held constant by expulsion of the g as produced by the reactions, the evolution of the Si-C-0 system with temperature occurs in several steps, although the main transformations happen at the univariant points shown in a PRT diagram (pressure, P(C O)/P(SiO) ratio, temperature). The path followed by the system depends on the ratio of reactants initially present in the reactor. When the gas is expelled, the theoretical SiC yield from a C + SiO2 mixture is close to 100%. The Si yield remains low, although it increases rapidly with the imposed pressure. The gas must be recirculated to obtain a h igher yield.