Production of Silicon Carbide from Rice Husks

Abstract

This paper reports the formation of ß‐silicon carbide by the process of pyrolyzing rice husks (RH). The sequence of transformations and the mechanism of formation of crystalline silica, carbon, and silicon carbide from RH were investigated in detail. The structural evolution of silicon carbide particulates during the conversion process was critically examined by various techniques. Studies using X‐ray diffraction and infrared spectroscopic techniques revealed that a temperature of 1500°C is desirable for the completion of the reaction between RH silica and carbon, thereby leading to the formation of ß‐silicon carbide. Except for the gradual change in the morphology leading to the formation of dense crystals of ß‐SiCp, formation of alpha‐SiCp was not evidenced in the present studies. The fine particle size of ß‐SiC, formed at lower reaction temperatures, apparently precluded the transformation to alpha‐SiC.