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 SiO 2 by gas mixtures containing CH 4 , H 2 , 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 lm were exposed to the gas mixture for 6 hours. Influence of temperature and CH 4 \H 2 ratio was investigated. Higher temperature and CH 4 concentration resulted in greater SiC production. Two kinds of SiC were found: one was deposited between SiO 2 particles, the other one was deposited inside the SiO 2 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.