PRODUCTION OF ULTRAFINE PARTICLE OF TUNGSTEN OR TUNGSTEN OXIDE

摘要

PURPOSE:To improve the yield of ultrafine particles in the production of ultrafine particle of tungsten or tungsten oxide from powdery tungsten or tung sten oxide raw material using high-temperature plasma process by using nitrogen gas as a core gas and an atmospheric gas and generating the high-temperature plasma under slightly reduced pressure. CONSTITUTION:100% nitrogen gas or a mixed gas composed mainly of nitrogen gas and added with argon gas is used as a core gas G and an atmospheric gas and high-temperature plasma is generated under slightly reduced pressure. Powdery raw material 4 consisting of tungsten or tungsten oxide is carried by a carrier gas CG having the same composition as the above gas and is continuously introduced (with a plasma jet gun 2) into the plasma flame P. Ultrafine particles are formed from the above powdery raw material 4 by this process and the ultrafine particles floating in the atmospheric gas flow sucked (with a pump 9) to maintain the slightly reduced pressure atmosphere are contin uously collected and recovered 9. The above slightly reduced pressure is prefer ably =700torr.