Tungsten Oxide

Tungsten ore is mainly scheelite. The world's scheelite accounts for more than 2/3 of total, and China accounts for 72.1%. Some scholars have improved the method of using ammonium sulphate to decompose scheelite to prepare ammonium partrungstate . (1) Tungsten containing sulphuric acid and phosphorus mixed acid solution, wherein the concentration of tungsten trioxide is 25-150g/L, the concentration of phosphoric acid is 10 ~ 200g/L, and the concentration of sulphuric acid is 1.5 ~ 2.5mol/L. (2) The obtained tungsten containing mixed solution of sulphuric acid and phosphoric acid was mixed with oil to extract the two phase volume ratio of oil phase: water phase = 3:1-1:3, and the loading organic phase was obtained. (3) The obtained load organic phase was extracted by distilling water with volume ratio as oil phase: water phase = 3:1-10:1, and the stripping solution was obtained. (4) Ammonia was added to the stripping solution to control the free ammonia in the solution at 1-2mol/L a

Tungsten tin ore is a brittle mineral, which is extremely easy to be milled and polished during mineral processing, causing inconvenience to mineral processing. Some scholars have proposed a method of mineral processing for tungsten tin ores. The content of Sn in the mineral materials is 0.083 to 0.32% and the content of WO3 is 0.035 ~ 0.46%. The steps and the pharmaceutical system are as follows: (1) The tungsten tin minerals are removed to some monomers and the jigging branch separation technology is used to separate the minerals into coarse heavy minerals and fine grain aggregates, and then the coarse and fine grain aggregate minerals are reselected. (2) Coarse and heavy minerals are selected by spiral chute, and the coarse concentrate and spiral chute tailings are obtained, and the spiral chute coarse concentrate rocking bed is selected. The coarse tungsten and tin concentrate 1, the rocking bed middle mine 1 and the rocking tailings tailings 1 are obtained. (3) The fine aggregate

Compared with ordinary powder, WC nano powder has advantages of small particle size, large surface area and high reactive activity. It has remarkable advantages in chemical synthesis, fuel cell and other fields. Therefore, it is of great significance to study a method for preparing high-quality single phase tungsten carbide nano powders. Some scholars have provided a method for preparing tungsten carbide nitride nanopowders based on nitride conversion method, including the following steps: 10mmol deionized AMT and 50mmol citric acid were dissolved in 100ml deionized water to get clarified mixed solution; complex reaction was carried out at 70°C for 5 hours; filtration and drying for 12 hours at 120°C, the precursor of tungsten oxide was obtained. The WO3 powder was obtained by calcining at 650°C for 3 hours. The WO 3  powder is placed in a tube furnace and nitrided through ammonia gas. The flow rate of ammonia is controlled at 3L/min, the temperature is 700°C, the heating rate is 2°C/m

Tungsten powder is the main raw material for the processing of powder metallurgy tungsten products and tungsten alloys. With the rapid development of the microelectronics industry, energy, aviation, machinery industry and other fields, the demand of ultrafine tungsten powder is increasing day by day. At present, the main process methods of nano tungsten powder include hydrogen reduction, sol-gel, high energy ball milling, freeze-drying, molten salt electrolysis, self propagating high temperature reduction and spray drying fluidized bed. In order to solve the problem of preparing ultrafine tungsten powder, scholars have provided a processing technology for nanometer tungsten powder. (1) Ceramic ball mill can be put into a microwave oven by placing a metal powder, a 10-20 micron blue tungsten or yellow tungsten powder, a ceramic ball with a particle size of 0.5 millimeters and the ratio of deionized water to a ceramic ball mill in a proportion of 1:5. (2) The motor and microwave oven tha

Heteropoly acid is one of the most active catalysts in acid catalytic reaction and redox reaction. Phosphotungstic acid H 3 PW 12 O 40 •nH 2 O is the most widely used in heteropoly acid. The purity of phosphotungstic acid directly affects the conversion rate of the catalytic system. Therefore, the preparation of high purity phosphotungstic acid is especially important. Some scholars have proposed a purification method for phosphotungstic acid crystals. (1) The crystal of industrial phosphotungstic acid is dissolved in water and the inorganic acid is added to the solution of phosphotungstic acid containing inorganic acid. The concentration of tungsten trioxide is 50-150g/L, and the volume molar concentration of the inorganic acid is 0.5 ~ 6mol/L. (2) In the solution of phosphotungstic acid containing inorganic acids, the oil phase organic alcohol extractant was extracted with the volume concentration of 5-50%, and the volume ratio of the two phase was oil phase = 1:1-10:1, and the organ

Tungsten ore is mainly scheelite. The world's scheelite accounts for more than 2/3 of total, and China accounts for 72.1%. Some scholars have improved the method of using ammonium sulphate to decompose scheelite to prepare ammonium partrungstate . (1) Tungsten containing sulphuric acid and phosphorus mixed acid solution, wherein the concentration of tungsten trioxide is 25-150g/L, the concentration of phosphoric acid is 10 ~ 200g/L, and the concentration of sulphuric acid is 1.5 ~ 2.5mol/L. (2) The obtained tungsten containing mixed solution of sulphuric acid and phosphoric acid was mixed with oil to extract the two phase volume ratio of oil phase: water phase = 3:1-1:3, and the loading organic phase was obtained. (3) The obtained load organic phase was extracted by distilling water with volume ratio as oil phase: water phase = 3:1-10:1, and the stripping solution was obtained. (4) Ammonia was added to the stripping solution to control the free ammonia in the solution at 1-2mol/L

Carbon supported platinum catalysts are regarded as ideal fuel cell catalysts. However, the interaction between the carbon carrier and platinum is weak, the carbon carrier is easy to corrode. The nano platinum particles can easily migrate on the surface of the carrier, grow up and even lose, which leads to the degradation of the catalyst activity, and eventually leads to the shorter service life of the fuel cell. In view of the disadvantages of poor stability and activity of existing fuel cell cathode catalysts, some scholars have used sol-gel method to evenly coat titanium tungsten oxide on the surface of carbon nanotubes, and then heat treatment to form titanium tungsten with high crystallinity and high electrical conductivity. The oxide coating, and thus the platinum catalyst, its main process is as follows: (1) 1 gram of carbon nanotubes, adding 160 ml of concentrated nitric acid, reheating for 3 hours, cooling, diluted by ultra pure water, filtering out the supernatant, centrifug

Tungsten doping is a promising and effective way to reduce the phase transition temperature of vanadium didioxide. Doping can improve the electrical properties of vanadium dididioxide thin films, reduce the square resistance of the films, and improve the resistance temperature coefficient of the films. Common methods of doping include evaporation, ion implantation, sol-gel and magnetron sputtering. Researchers have developed a method for preparing tungsten doped vanadium dioxide thin films, including the following steps: (1) The substrate is cleaned, and the cleaned substrate is put into the high real chamber. (2) Preparation of VO x /W/VO x  composite film: The argon, metal vanadium target and tungsten metal target are placed in the vacuum chamber, and the metal vanadium target and tungsten target surface are pre sputtered by the sputtering power source of vanadium target and the tungsten target sputtering power, respectively. When the vanadium target is sputter target, the tungsten