Evolution of chemistry and morphology during the carbonization and combustion of rice husk

Abstract

Both fine carbon/silica and pure silica powders can be obtained by carbonization and combustion of rice husk under non-isothermal conditions, and the products can be used for preparation of high-quality ceramic materials. Studies on the morphology, chemical and physical characteristics of products were carried out by N 2-adsorptionmeter, SEM, XRD, FTIR, ICP-MS and EA. Results indicate that decreasing the heating rate increased the specific surface area, pore volume and pore diameter. At a heating rate of 5 °C/min, the specific surface areas of both the carbon/silica and pure silica powders were 261 and 235 m 2/g, and the average pore diameters were 2.2 and 5.4 nm, respectively. The products obtained from various heating rates were all amorphous. Thermogravimetric analysis was employed to study the reaction characteristics during carbonization or combustion, indicating that decomposition process of rice husk could be divided into three temperature zones. This results of the study can also provide the important information on the recovery of biomass material from rice husk.