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.

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.

Tungsten trioxide and its hydrated oxides are important n-type semiconductor materials with a band gap between 2.4 and 2.8 eV. They have excellent physicochemical properties and unique electrocatalytic activity, and are applied in the fields of electrochromic, gas sensing, electrocatalysis, and photocatalysis.

Photoelectrochemical cells (PEC) decompose water to produce hydrogen by converting solar energy into chemical energy. It is considered to be one of the most important ways to obtain energy by replacing fossil energy, and it has received widespread attention. Finding a semiconductor material with potential applications through various methods is an important research direction in this field.

1. Solution to the wear of abrasive particle

When there is no other failure mechanism which plays an important role, the lifetime of bits depends on the wear state of the tungsten carbide button. The service life of the bits can be extended by improving the wear resistance of buttons appropriately. In addition, the wear resistance of the side button should be higher than that of middle button. 

Electrochromism refers to the reversible change in light transmittance and/or reflectance associated with an electrochemical redox reaction after the material is applied with an appropriate voltage. Applications of electrochromic devices include: smart windows for cars and buildings, controllable light reflection or light transmissive display devices (for optical information and storage), controllable aircraft canopies, reusable price tags, spacecraft Thermal control and more.