Nanometer violet tungsten oxide may be applied for producing ceramic microsphere. Violet tungsten oxide can be prepared by using APT as raw material. This process also requires the material - liquid ammonia. The quality requirements for liquid ammonia are: ammonia≥99.80%, residue≤0.20%. The main equipment used is industrial rotary tube furnace.
Preparation of violet tungsten oxide. The dried APT was quantitatively fed into the industrial rotary tube furnace, through which NH3 was passed by a screw conveyor. And APT was calcined under certain conditions. Since NH3 was decomposed to generate H2, APT was calcined under a mild reducing atmosphere. APT was gradually decomposed and reduced to form violet tungsten oxide. Its total reaction formula is:
3[5(NH4)2O?12WO3?5H2O]=2W18O49+40H2O+35H2+15N2
After the violet tungsten oxide was obtained, it was sent to the vibrating screen through the screw conveyor. Then, the obtained sample was examined. The phase composition was detected by X-ray diffraction method. The appearance of violet tungsten oxide, APT and tungsten powder was detected by scanning electron microscopy. The microstructure of violet tungsten xoide was detected by transmission electron microscopy.
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