| 摘要 |
To produce silicon nitride and silicon carbide whiskers, cereal chaff is pre-treated with acid and calcined and is then heated firstly in a nitrogen atmosphere, following which silicon nitride whiskers are removed, and secondly it is heated to a higher temperature in a non-oxidizing atmosphere, following which silicon carbide whiskers are removed, there being an addition of secondary feed material after the removal of the nitride whiskers, which feed material consists of further acid pre-treated calcined chaff and/or flakes of a mixture of silicon, silicon nitride and further silicon containing material with an organic binder. Removal of the nitride and carbide whiskers is achieved by treating in each case with a mixture of water an a hydrophobic organic liquid such as kerosene which mixture is allowed to separate. The final carbide residue can be burned to remove carbon and crushed to recover silicon carbide powder. |
