Silicon Carbide Formation Enhanced by In-Situ-Formed Silicon Nitride: An Approach to Capture Thermal Energy of CO-Rich Off-Gas Combustion

Carbothermic smelting of ores to produce metals results in large volumes of CO-rich off-gas, which is typically flared, causing energy wastage. This study aimed to propose an alternative method for capturing thermal energy from CO-rich off-gas combustion in the form of silicon carbide (SiC) derived from waste materials like quartz and anthracite fines. The research involved investigating the effects of quartz and anthracite particle size, treatment temperature, and the gaseous atmosphere (nitrogen or air) on the formation of SiC. Experiments revealed that a quartz-anthracite mixture with 90% of the particles less than 350.9 µm, treated at 1873.15 K (1600 °C), achieved nearly complete conversion of quartz to SiC in both nitrogen and air atmospheres. The findings highlight significant potential for the industrial application of this process, offering an efficient method to utilize CO-rich off-gas while producing valuable silicon carbide.