Silicon carbide from rice husk

Silicon carbide crystals can be manufactured from rice husk raw material. Rice husk is treated with an accelerator selected from the group consisting of boron compounds and lanthanum compounds prior to heating in the furnace. It is pretreating with an acid solution (e.g., 5N to 6N H2 SO4, HCl or HNO3) upto 10 percent and 40 percent of the weight of said rice husk raw material for a period of at least one and half hour prior to being heated in a furnace of non-oxidizing atmosphere. The acid treated raw material is arranged on a gas-permeable, heat-resistant support in a manner allowing the passage of a gas through said raw material. It is then placed in an air tight furnace at 400 to 1300 deg.C. for at least one hour to remove impurities. Then silicon carbide whisker-containing material can be removed from the furnace.