Violet tungsten oxide is a kind of photocatalyst with special surface structure and oxygen defect structure. In addition, copper can improve the response of the photocatalyst in the visible region. Therefore, copper modified violet tungsten oxide has broad application prospects in the field of photocatalyst.

Violet tungsten oxide is powder with unique color between dark purple and pure purple. It is generally prepared by calcining ammonium paratungstate in a rotary furnace. The color of violet tungsten oxide differs from different preparation methods.

With special surface structure and oxygen defect structure, violet tungsten oxide can be modified by copper ions, so as to have better photocatalytic properties. Copper modified violet tungsten oxide, which has a high rate of solar energy utilization, is an efficient photocatalyst.

In order to extract tungsten from tungsten minerals, at present, China's tungsten metallurgy industry mostly adopts the alkaline smelting system. After high-pressure leaching of sodium tungstate solution, ion exchange is carried out and apt is extracted by evaporation crystallization. At present, there are two outstanding problems in this process that have not been effectively solved: first, the waste water discharge is large. Second, the discharge of waste salt is large.