Scheelite is a troublesome raw material in tungsten smelting. With the popularization of alkali pressure leaching technology in the last century, the production capacity and scale of scheelite smelting have been greatly improved, and the technology has been further mature. Because of the excessive alkali process, although most of the alkali is consumed in the leaching process, the residual alkali in crude sodium tungstate solution is still very high after the reaction.

As a member of transition metal oxides, tungsten oxide (WO₃) is an indirect bandgap n-type semiconductor material with a band gap of 2.2-2.8eV. It has good absorption of visible light, so it is a very promising semiconductor photocatalyst. However, at present, there are many methods to prepare tungsten trioxide, which have poor controllability and difficult to grasp the photocatalytic performance.

Tungsten oxide is a kind of transition metal oxide, which belongs to n-type semiconductor and has a wide range of applications. At present, a large number of studies have found that tungsten-based oxides not only act as catalysts, electrochromic, solar energy absorption materials and invisible materials, but also have the characteristics of semiconductor functional materials such as thermal, pressure and gas sensitivity.

In order to prepare tungsten powder from ammonium paratungstate, tungsten oxide should be burned in a weak reduction atmosphere before hydrogen reduction is a common method in industry. The tungsten powder prepared by this process is mostly polycrystalline, which is the main material for preparing tungsten alloy and tungsten carbide.