Rice hulls consist of cellulose and silica(about 13 wt.\%), which are the raw materials for the formation of silicon carbide.
Thermogravimetric analysis was used to investigate the kinetics of the formation of the silicon carbide from rice hulls. The overall reaction is $SiO_2+3C$ → SiC + 2CO and was studied in the temperature range between 1350 and 1450℃. The reaction of SiC formation followed a linear rate raw and the experimental activation energy was 146 kcal/mole.
The advantages of SiC formation from rice hulls are the high surface area and the intimate contact of the reactants.
The effect of iron powder as a catalyst was investigated. The reaction rate was increased with increasing surface area of catalyst, but the reaction rate was independent of the amount of catalyst for concentrations greater than 15%.