Medium blue tungsten oxide may be used to produce metal tungsten (W) powder. The blue tungsten oxide (BTO) may be made into W powder by reduction method. Certainly, BTO may also be obtained by reducing yellow tungsten oxide. There are four methods for reducing W powder with industrial value: carbon reduction method, carbon-containing gas reduction method, decomposition ammonia reduction method, and hydrogen reduction method. Among them, the most widely used method is hydrogen reduction method. The W powder obtained by…
Tungsten Oxide
Coarse blue tungsten oxide’s main raw material is ammonium paratungstate (APT). APT is a white crystal. The production process of ammonium paratungstate varies. It depends on the type of tungsten concentrate used and the impurity contained. Several Kinds of Production Processes of Ammonium Paratungstate 1. Soda boiling black tungsten concentrate (caustic soda) at high pressure – ion exchange – evaporation crystallization; 2. Soda boiling black tungsten concentrate (caustic soda) at high pressure – solvent extraction – evaporation crystallization; 3. Pressure…
Fine blue tungsten oxide is a blue powder with the grain size of 7~12μm. Basic Measurement Principle of Oxygen Index in Blue Tungsten Oxide The oxygen index is used to characterize the change of the number of oxygen atoms in blue tungsten oxide (BTO), that is, to reflect whether the content of tungsten contained in BTO powder is high or low. The larger the value, the lower the content of tungsten in blue tungsten oxide, and vice versa. The determination…
99.5% yellow tungsten oxide is a yellow powder with high purity. The determination process of Si in the yellow tungsten oxide is available by silicon molybdenum blue spectrophotometry method, which is easy to operate by dissolving yellow tungsten oxide with NaOH solution and complexing tungsten with citric acid. The measurement range of ωSi is from 0.0004% to 0.016%, the recovery rate is at the range of 95.71%~118%, and the relative standard deviation is less than 14.32%. Silicon Molybdenum Blue Spectrophotometry…
99.95% yellow tungsten oxide may be applied to produce fireproof fabric. Fireproof fabric is designed to resist burning and withstand heat. And it can not only effectively prevent the spread of flame, but also can protect the original performance of the fabric products. Therefore, it is usually used in special industries for special types of protective fabrics. Studies have found a flame retardant and heat resistant nano magnesium oxide doped polyvinyl dc cable materials, by adding nano tungsten trioxide to…
99.9% yellow tungsten oxide, or 3N yellow tungsten oxide, is a kind of yellow powder with relative high purity. Spray Pyrolysis Method to Produce Nano Yellow Tungsten Oxide By dissolving tungstic acid (H2WO4) in alkali solution containing ammonia under a certain ratio, by ultrasound spray conversion and vacuum drying to get nano YTO powder. Actually, this method is an aerosol process which belongs to vapor phase method. But it uses liquid phase as precursor. Therefore, it has the advantages of…
99.99% yellow tungsten oxide may be produced by microemulsion method. This method adopts ammonium tungstate solution as raw material. The processes are shown as follows: 1. Add the ammonium tungstate solution into emulsion with surfactant. 2. After super-emulsifying, add in strong acid such as hydrochloric acid (HCL) and sulfate (H2SO4) to react and precipitate. 3. After centrifugal precipitants, clean the precipitants with solvent. 4. Dry to get yellow tungsten oxide. In microemulsion method, surfactant and co-surfactant is composed of a…
Tungsten tetraiodide is a black powder with CAS number of 14055-84-6, molecular formula of WI4, molecular weight of 691.458, and relative density of 5.218. Tungsten tetraiodide has a variety of properties as follows: 1. Easily hydrolyzed and easily oxidized. 2. Not dissolved in cold water. Decomposed in hot water. Soluble in ethanol. Insoluble in ether, chloroform and turpentine. 2. Decomposed by heating. There is no fixed melting point and boiling point. Heated to decompose into WI2 and I2 in the…
Tungsten disulfide is a kind of dark gray crystal or powder with similar lubricating property to graphite. Its CAS No. is 12138-09-9; Chemical formula is WS2; Melting point is 1250°C. Structure WS2 has a layered structure related to MoS2, with W atoms situated in trigonal prismatic coordination sphere. Owing to this layered structure, WS2 forms inorganic nanotubes. Properties 1. WS2 converts to tungsten trioxide if heated in oxygen-containing atmosphere. 2. WS2 does not melt but decomposes to tungsten and sulfur…
Tungsten hexafluoride is also called tungsten (VI) fluoride with CAS No. is 7783-82-6 and molecular formula of WF6. Tungsten hexafluoride is a colorless diamagnetic gas at ambient pressure and temperatures above 17 °C. The WF6 molecule is octahedral. And it condenses into a pale yellow liquid between 2.3 and 17°C with the density of 3.44g/cm3 at 15°C. At 2.3°C, it freezes into a white solid having a cubic crystalline structure with calculated density 3.99g/cm3. Whereas WF6 gas is one of…