Method for synthesizing high-purity silicon carbide raw material for growing silicon carbide single crystals

The invention relates to a method for synthesizing a high-purity silicon carbide raw material for growing silicon carbide single crystals. The method comprises the following steps of: preparing raw materials, wherein high-purity Si powder and high-purity C powder are used as raw materials, and the molar ratio of the high-purity Si powder to the high-purity C powder is more than 1:1 and less than 1.5:1; pretreating, namely putting the high-purity Si powder and the high-purity C powder in a crucible, placing in a heating furnace, vacuumizing the growth chamber of the heating furnace until the high vacuum is formed and the pressure is less than 1*10 Pa, and heating to 600 to 1,300 DEG C; synthesizing at high temperature, namely keeping reacting at reaction temperature of between 1,500 and 2,500 DEG C in the high-purity non-oxidizing atmosphere under specified pressure for 2 to 20 hours; and reducing to room temperature to obtain the high-purity silicon carbide raw material for growing the silicon carbide single crystals.