Carbo-Chlorination of Silica: Thermodynamic Simulation and Experimental Study

Carbo-chlorination of silica represents an interesting route to prepare SiCl4, which is an important precursor used in the chemical industry and microelectronic industry. Chlorination of several silica-containing materials in the presence of carbon was studied at atmospheric pressure in an isothermal reactor at laboratory scale, with continuous and stable gas flow. The influencing factors such as temperature, C/SiO2 mole ratio and binder content in the mixture were studied. The experimental results showed that diatomite is the optimal material for carbo-chlorination to prepare SiCl4. The conversion ratio of silicon dioxide increases with C/SiO2 mole ratio, decreases with binder content increased in the mixture. SiO2 + 2Cl(2) + 2C = SiCl4 + 2CO to be the dominant reaction above 800 degrees C according to the thermodynamic calculation. Based on the results, a probable procedures of the carbo-chlorination is proposed.