Tungsten slag is produced in tungsten smelting process, that is, tungsten ore and waste tungsten carbide raw materials are decomposed by wet method in high temperature or aqueous solution to obtain primary tungsten products (sodium tungstate, ammonium paratungstate) and solid waste slag (i.e. tungsten slag).

Tungsten metal has excellent physical and chemical properties, such as high melting point (3410 ℃), high density (19.35g/cm³), high conductivity/thermal conductivity, excellent high temperature strength and hardness, low work escape, very low thermal expansion coefficient and vapor pressure, and good corrosion resistance, which makes tungsten an important functional material and high temperature structural material.

Q-switched laser technology is a technology that compresses the general output continuous laser energy into a very narrow pulse to emit, so that the peak power of the light source can be increased by several orders of magnitude. Because Q-switched lasers can obtain high peak power and narrow pulse width, they are widely used in industrial processing and scientific research fields, such as the manufacture of ultrafine semiconductors, terahertz wave equipment and so on.

Non-noble metal sulfides are layered materials with graphene-like structure, which have good applications in catalysis, microelectronics, semiconductor and other fields. Tungsten sulfide and molybdenum sulfide catalysts have been used as hydrogenation catalysts in petroleum processing. They are widely used in hydrodesulfurization, hydrodenitrification, hydrodearomatization, hydrodeoxygenation and hydrodemetallization.