Blue nano tungsten oxide for near infrared shielding material may be prepared by using ammonium paratungstate as a raw material.
During preparation, the APT raw material is placed on the feed hopper of the feed port. The APT slides down along the inverted cone of the feed hopper and enters the feed pipe. Push the feed tube along the feed tube under the push of the feed screw in the feed tube. Since the furnace tube can be rotatably installed in the heating furnace, and the feed port is slightly higher than the discharge port, the material in the furnace can move forward along the furnace tube under the rotation of the furnace tube. There are 3~6 heating zones in the furnace tube. And each zone has different heating temperatures. The furnace tube becomes a container with better sealing property, since the feeding port adopts the feeding hopper of the inverted cone, and the discharging port is provided with the sealing discharge and the cooling device. After the furnace tube is heated by the furnace body, the APT entering the furnace tube is thermally decomposed into WO3, NH3 and water vapor under heating at a heating temperature of 400°C~600°C.
The thermally decomposed NH3 is further decomposed into N2 and H2 under the action of the catalyst of WOX. Then, the reaction temperature is set at 550°C~800°C, and the pressure of the furnace gas is adjusted to 0~2mbar, so that WO3 can be reduced to blue tungsten oxide by H2.
More details, please visit:
http://www.tungsten-powder.com/Blue-Tungsten-Oxide.html
