With the development of semiconductor technology, the manufacture of camera sensor technology (CIS: CMOS image sensor) with metal oxide semiconductor technology has become a mainstream process in the field of emerging imaging. Among them, the metal film has a good visible light reflection conduction property, and is widely used as a reflection or isolation layer of incident light in the industry.

High strength, high toughness, high hardness, light weight, high temperature resistance and corrosion resistance are the main development directions of high performance structural materials. Tungsten, with its excellent high temperature resistance, high strength and hardness, is an irreplaceable key material in many fields, especially in the field of national defense, military industry, aviation and aerospace.

Phosphotungstic acid and silicotungstic acid are the main members of the heteropoly acid family. They have high catalytic activity, good selectivity, no pollution to the environment and little corrosion to equipment. They are a kind of green catalysts with great development prospects. In practical applications, scholars believe that immobilizing heteropoly acids on matrix materials can not only make the catalyst easy to recover and continuous production, but also greatly improve the specific surface area and catalysis, which is conducive to improving product quality and reducing production costs.

Nickel-tungsten catalysts are widely used in hydrofining and hydrocracking. Their main components are about 25% tungsten trioxide, 2% nickel oxide, 50% alumina, 5% silicon dioxide and a small amount of iron and vanadium. Waste nickel-tungsten catalysts contain tungsten, nickel and other metals. If they can be recycled, they will produce enormous economic benefits. At the same time, the pollution and damage to the environment caused by waste nickel-tungsten catalysts are avoided.