Nitrogen oxide (NO_x) is one of the sources of air pollution and poses a great threat to human health. Thermal power plant is one of the main sources of NO_x emission. At present, the main dry flue gas denitrification method is selective catalytic reduction (SCR), the key part of which is catalyst.

Metal tungstates are a kind of important inorganic materials. They have good application prospects in optical fibers, scintillation materials, photoluminescent materials, humidity sensors, magnetic devices, microwave applications, catalysts and corrosion inhibitors. Among them, zinc tungstate nanomaterials are good materials for photoluminescence, photocatalysis and gas sensing. However, pure zinc tungstate nanomaterials are less sensitive to hydrogen.

Tungsten carbide spraying powder is the basis of preparing tungsten carbide wear-resistant coatings by thermal spraying. To prepare tungsten carbide wear-resistant coatings with self-lubricating properties, self-lubricating additives must be added to tungsten carbide spraying powder. At present, self-lubricating additives mainly include soft metals (Au, Ag, etc.), fluoride (LiF₂, CaF₂, etc.) and so on. Disulfides (MoS₂, WS₂, etc.) and metal oxides (Zr₂O₃, Cr₂O₃, etc.) have been extensively studied as lubricating phases for coatings. 

At present, hydrofining catalysts are usually prepared by introducing active metal components from solution or suspension into the carrier through impregnation, and then by drying and calcination. Among them, nickel cobalt molybdenum tungsten sulfide is a highly active hydrodesulfurization catalyst.

In many scheelite deposits in China, scheelite is not only associated with scheelite, but also with wolframite. For example, Xingluokeng, Fujian Province, is a super-large wolframite-scheelite deposit, with tungsten reserves of about 300,000 tons, and scheelite and wolframite reserves accounting for half of each.

Fluorite is the most important mineral in fluoride. It has unique physical and chemical properties and wide uses. It plays an important role in industrial development. Like tungsten, fluorite reserves, mining and exports in China rank first in the world.

At present, in the production of tungsten powder, most of the tungstate thermal decomposition of blue tungsten oxide, blue tungsten oxide hydrogen reduction process to tungsten powder. The conventional process generally uses ammonium paratungstate as the initial raw material, but it is difficult to obtain ultrafine tungsten powder with average particle size of less than 1 micron by hydrogen reduction.

Carboxylic esters are a kind of basic organic chemical raw materials. They are widely used in perfumes, flavors, plasticizers, solvents, resins, coatings, cosmetics, pharmaceuticals, surfactants and organic synthetic intermediates. They have broad market demand at home and abroad.

Hydrogen is a kind of clean energy with high calorific value, friendly environment and convenient transportation. The combustion product is water, which does not cause any harm to the environment. The earth is rich in water, easy to get and cheap. Sunlight is an ideal way to convert solar energy into chemical energy.

Tungstate nanomaterials have been widely used in many fields, such as optics, electricity, magnetism, conductor/superconductor, catalysis, biology and so on. The synthesis methods of transition metal tungstate materials mainly include sol-gel method, copolymer-assisted synthesis method, inverted micelle soft template method, wet chemical method and solution synthesis method.