Reduction of SiO2 to SiC using natural gas

Abstract

This paper presents a preliminary study of SiC production by use of natural gas for reduction of silica. Direct reduction of SiO2 by gas mixtures containing CH4, H2, and Ar was studied at temperatures between 1273 K and 1773 K (1000 °C and 1500 °C). Silica in form of particles between 1 and 3 mm and pellets with mean grain size 50 µm were exposed to the gas mixture for 6 hours. Influence of temperature and CH4\H2 ratio was investigated. Higher temperature and CH4 concentration resulted in greater SiC production. Two kinds of SiC were found: one was deposited between SiO2 particles, the other one was deposited inside the SiO2 particles. Although the exact reaction mechanisms have not been determined, it is clear that gas-phase reactions play an important role in both cases. The reaction products were analyzed by Electron Probe Micro Analyzer.