Nano violet tungsten oxide for producing ceramic microsphere can be prepared by using ammonium paratungstate (APT) as raw material, and performing hydrogen reduction in industrial rotary furnace under wet hydrogen and high temperature conditions.
According to the APT hydrogen reduction method, the improved industrial rotary furnace is used for reduction. The liquid ammonia (first grade, NH3 content ≥99.8%) is vaporized and passed into the rotary kiln. And the screw feeder is used to feed the APT (with a WO3 content of 88.96%, an average particle size of 43.7μm, and a bulk density of 2.22g/cm3) into the furnace at a certain feeding speed and calcined at a certain temperature. Since the decomposition of NH3 produces H2, the APT is calcined in a reducing atmosphere. And it is gradually decomposed and reduced to violet tungsten oxide, which is passed through an 80 mesh sieve.
The physical properties, phase composition and morphology of the obtained violet tungsten powder were observed by an average particle size analyzer, a specific surface measuring instrument, an X-ray diffractometer, and a field emission scanning electron microscope.
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