Tungsten Oxide

Because the grain uniformity of hard alloy mainly depends on the particle size distribution of WC powder, the particle size distribution of WC powder is hereditary in tungsten powder . Therefore, the preparation technology of tungsten powder and tungsten carbide powder by submicron size and narrow size is very important. The key technical indexes of fine grain, submicron, ultrafine or nanocrystalline cemented carbide for WC powder are the purity, particle size and particle size distribution, and it is clearly stipulated that there is no type of type III coarse in WC powder. Some scholars have adopted the following technical schemes to prepare submicron tungsten powder or tungsten carbide powder, including the following steps: (1) Ammonium paratungstate (APT) is pyrolyzed to ammonium metatungstate (AMT) and dissolved in ammonia solution or deionized water and filtered to obtain ammonium tungstate solution, or using ammonium paratungstate (APT) production line after ion exchange or cryst...

At present, the general method of preparing tungsten oxide is liquid phase method. In the process of preparing tungstic acid in liquid phase, the tungstic acid particles are automatically coalesced because of the unstable thermodynamics. In addition, the free water molecules on the surface of the particles form hydrogen bonds with the free hydroxyl groups, and then form a hydrogen chain with the water molecules on the surface of the adjacent particles to produce a bridging action. Some scholars have proposed a method of adjusting the length of tungsten oxide nanorod by oxygen, with a surface functionalized carbon nanotube with a diameter of 2-200 nm and a layer of 1-30 layers as the carrier, tungsten metal salt as the tungsten source, the addition of hydrochloric acid in the carbon nanorod glycol suspension and tungsten metal salt system, and the principle of making the weak acid with strong acid to make tungstate granules. It directly forms on the surface of the carbon nanotubes and ...

The wolframite is brittle and easy to smash and produce fine slime, and most of them have fine embedded granularity and more useful metal minerals. The gangue minerals are closely related to tungsten minerals, and the separation is difficult. Many fine grain tungsten can not be recycled. Then it forms tailings. Some scholars have proposed a comprehensive mineral processing scheme for recycling wolframite from tailings, including the following steps: (1) Centrifuge gravity separation and tail preconcentration, after the wolframite tailings are adjusted to pulp, the centrifugal concentrator is used to preconcentration and discarding tailings, and the concentrate and tailings of centrifugal gravity separation are obtained. (2) The concentrate is floated by the first coarse second sweep process, and the flotation tailings and sulfide ore concentrate are obtained. (3) Magnetic separation of flotation tailings by magnetic separation is carried out, and magnetic separation concentrate and ma...

High purity tungsten, which means more than 99.995% of the purity of tungsten, is a key material for the formation of the diffusion barrier in the process of mass integrated circuit and PVD coating. High purity tungsten powder has become an indispensable raw material for the microelectronics industry. Some scholars have put forward the preparation method of high purity tungsten powder for scale integrated circuit, which aims to make the production of high purity tungsten powder with purity not less than 99.999%, and to ensure the controllability of the particle size and morphology of tungsten powder. The process is as follows: (1) Using the industrial 0 grade ammonium parotungstate in GB/T10116-2007 as raw material, the three band rotary tube air furnace is calcined to form yellow tungsten. The temperature of the three zone is 550 + 5°C, 600 + 5°C, 600 + 5°C.  The concentration of yellow tungsten is dissolved in 10% ammonia water at 50-60°C, the initial concentration of solution is...

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...