| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing silicon nitride powder by a direct nitrification method using a nitrification oven equipped with a gas-charging pipe and a gas-discharging pipe and used for producing the silicon nitride, enabling to prevent the gas-discharging pipe from clogging by the deposition and adhesion of silicon monoxide to the inside of the gas- discharging pipe, and enabling to constantly stably and continuously operate also a nitrification oven for continuously producing the silicon nitride over a long time, even when the continuous nitrification oven is used, thereby enabling to efficiency and profitably produce the silicon nitride powder. SOLUTION: This method for producing silicon nitride powder comprises directly nitrifying metal silicon with a non-oxidizing gas containing nitrogen gas or ammonia gas in a temperature range of 1,150-1,500 deg.C by the use of a nitrifying over equipped with a gas-charging pipe and a gas-discharging pipe and used for producing the silicon nitride. Therein, the linear rate for discharging the gas after the nitrification reaction is 3 to 50m/s in a temperature range of 1,000-1,200 deg.C in the gas-discharging pipe. In the method for producing the silicon nitride powder, a nitrification over for continuously producing the silicon nitride is used as the nitrification oven for producing the silicon nitride, and a nitrification produce/discharged gas ratio after the nitrification reaction is 0.03-0.3kg/m<3> in a temperature range of 1,000-1,200 deg.C in the gas-discharging pipe. |
