The fractionation and purification processes of rice hull fiber andnatural silica from rice hull

摘要

Rice hull is one of the most abundant agricultural residues generated as a byproduct during the rice milling process in rice producing countries, such as KOREA. Utilization of the rice hull has gathered many attentions although it still require more sophisticated technologies to make valuable products from the rice hull.In this study, we developed a refinery process for the integrated usage of rice hull. Rice hull fiber and silica were successfully separated by the biorefmery process based on the alkaline treatments. In order to increase the efficiency of the rice hullbiorefmery process, various conditions were applied and the products after the process were deeply examined. The rice hull fibers obtained from the process were tested as the alternative to wood fibers.The liquor solution obtained by the refinery process of the rice hull included large amounts of silica, which is commonly used as industrial material. The process conditions were optimized to obtain silica with high purity and porosity from the liquor solution. The silica powders were reduced by a magnesiothermic reduction process. The morphology of the reduced silicon was almost identical to that of the rice hull-derived silica. The specific area and pore volume of silicon powders were 176.16m2/g and 0.77 cm3/g and the purity measured by inductively coupled plasma (ICP) analysis was 99.98% which were commonly more 3 nine purity.