Thermal Sprayed tungsten carbide coating is a common wear-resistant coating with high microhardness and low oxide content. It has been widely used in aviation, machinery and other industrial fields. Because of the high hardness of the tungsten carbide coating, the friction coefficient of the friction system is large, which will cause serious wear and tear to the friction pairs matched with the tungsten carbide coating, even affect the service life of the wear-resistant protective coating.

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. Impregnation is a common method to prepare supported catalysts, but there are some problems such as uneven metal components on the surface of the support, large particles of active components and uneven dispersion.

There has always been a low (poor) grade tungsten tin associated ore in the tungsten-tin production industry, especially in Yunnan Province. Due to the similarity of the material and chemical properties of the two metal compounds, the separation of the two metals in the industrial production process has always been a difficult problem for the industrial production technology. The traditional production methods have always had the defects of high pollution and high energy consumption, and it is difficult to conform to the national industrial policy.

The traditional tungsten soft waste recovery and treatment process is firstly to convert the soft waste into sodium tungstate solution by NaOH solution cooking, and then crystallize the sodium tungstate crystal; then dissolve the crystal in the circulating mother liquor, regenerate the sodium tungstate solution, and then extract the tungsten from the solution by organic extractant and purify the ammonium tungstate. The ammonium salt of ammonium tungstate is evaporated. It can be seen that the recovery method is no different from the conventional treatment process, but in fact, because of the waste, there are some defects such as high operating cost, environmental pressure and so on.

At present, the main method to decompose tungsten minerals in industry is the NaOH decomposition process. Obviously, the traditional method can not cope with the decomposition of wolframite and scheelite mixed symbiotic ore. Therefore, a set of effective combination scheme is also very important.

Fluorite is the most important mineral in fluorides. It has unique physical and chemical properties and it is widely used. The reserves, production and export of fluorite in China are the first class in the world.

In the production of tungsten powder, tungstate thermal decomposition is mostly used to produce 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 1μm by hydrogen reduction.

China has abundant tungsten resources, for the mixed materials containing wolframite, such as high calcium wolframite concentrate, refractory tungsten material, tungsten fine slime and scheelite ammonia leaching residue, only sodium hydroxide leaching can only dissolve wolframite and it can not leach scheelite. If hydrochloric acid leaching alone can only dissolve scheelite, the wolframite can not be leached.

Carboxylic ester is a kind of basic organic chemical raw material. It is applied to perfume, essence, resin, paint, cosmetics, medicine, surface active agent and so on. It has wide market demand at home and abroad. At present, organic acid and alcohol are used as raw materials, and concentrated sulfuric acid as catalyst. Concentrated sulfuric acid as an esterification catalyst has some disadvantages, such as corrosion equipment, environmental pollution, and so on. Therefore, replacing the traditional catalyst with solid catalyst has become an important field of catalytic research.

Hydrogen is a clean energy and does not cause any harm to the environment. The earth is rich in water and low in price. Sunlight is an ideal way to convert solar energy into chemical energy.