| 摘要 |
PURPOSE:To prepare efficiently ultrafine beta-type silicon carbide powder having <=1mu average particle diameter, by reacting a specific particulate raw material consisting of carbon powder and silica at a specific temperature while dropping the raw mterial into a reaction vessel. CONSTITUTION:A granular raw material, obtained by kneading (A) carbon powder having 1-1,000m<2>/g specific surface area, e.g. thermal black, with (B) silica by using (C) a binder, e.g. petroleum pitch or a phenolic resin, and (D) an organic solvent, e.g. benzene, hexane or carbon tetrachloride, and granulating the resultant kneaded material, and having about 10-60% porosity and about 0.4-1.13g/cm<3> bulk specific density is used for preparing silicon carbide powder. Thus, the above-mentioned granular raw material is introduced from an introductory port 1 above a reaction vessel 6 and freely dropped and passed through a preheating zone 2 and a heating zone 3, heate uniformly by a graphite heating element 8 in the horiztonal direction at 1,500-2,000 deg.C and reacted. The resultant reaction product (ultrafine silicon carbide powder) is then passed through a cooling zone 4 and discharge outlet 5 and obtained. |
