Method for producing high-purity silicon carbide powder

Abstract

A method for producing high-purity silicon carbide powder includes filling starch-based packing chips or expanded starch as organic raw material into a container open at the top; introducing the container filled with the raw material into a furnace and heating the packing chips, or the expanded starch, gradually to a temperature of 2,000° C. whilst feeding inert gas or under vacuum to graphitize the packing chips or the expanded starch into porous graphite pieces; feeding halogen gas, such as chlorine or fluorine, into the furnace to purify the porous graphite pieces at a temperature of >1,800° C. to remove foreign metals from the porous graphite pieces by forming metal chloride, and converting the porous graphite pieces into powdered silicon carbide by feeding SiO with argon as carrier gas at a temperature of >1,200° C. at a pressure of 30 mbar or higher.

Dependencies are inferred from the claim text.