THE CHLORINATION KINETICS OF RICE HUSK

Rice husk was processed by acid-leaching and pyrolysis techniques to remove impurities other than silica and carbon and then further chlorinated to produce silicon tetrachloride. The chlorination of pyrolyzed-husk pellet was investigated by a thermal gravimetric analysis (TGA) reaction system over the temperature range of 973-1373 K. The effects of gas flow rate, pellet size, pellet-forming pressure, initial grain sizes, and temperature on the extent of chlorination were studied extensively. The rate expressions of the chlorination of pyrolyzed-husk pellet in the reaction-controlled region were presented. The reaction order with respect to chlorine concentration, 0.52, and the activation energy, 53.21 kJ/mol, were found. A kinetic model based on the degree of contact between silicon dioxide and carbon was developed, and it gave good agreement with the experimental results.