
Super grade violet tungsten oxide nanopowder may be prepared by calcining ammonium paratungstate with formula of 5(NH4)2O?12WO3?5H2O, APT for short. The steps for calcining APT to prepare super grade violet tungsten oxide nanopowder are as follows: Step one: Feed 5(NH4)2O?12WO3?5H2O from the feed inlet into the heated furnace tube with a feeding device, gradually moving from the low temperature zone to high temperature zone under the rotation of inclined furnace tube. Step two: Calcine 5(NH4)2O?12WO3?5H2O to generate WO3, NH3 and…