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What is Tungsten trioxide?

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What is Tungsten trioxide?
Tungsten trioxide is a powder metallurgical raw material for the production of cemented carbide and tungsten products. According to the national standard (GB/T 3457-1998), there are two types: tungsten trioxide (yellow tungsten for short), with the molecular formula WO3, and blue tungsten oxide (blue tungsten for short, which is a kind of mixed tungsten oxide). W20O58. Yellow tungsten is light yellow crystalline powder, and blue tungsten is dark blue or blue-black crystalline powder.
The physical and chemical properties of tungsten oxide
Tungsten trioxide (Tungsten trioxide) is a light yellow triclinic powder crystal. When the temperature is higher than 740°C, it turns into orange tetragonal crystals and returns to its original state after cooling. It is stable in the air, the melting point is 1473°C, the boiling point is higher than 1750°C, and the relative density is 7.16.
Tungsten trioxide is the most stable kind of tungsten oxide. It is insoluble in water and inorganic acids except for hydrofluoric acid. It can be dissolved in hot concentrated sodium hydroxide solution and ammonia to form a soluble tung state. When the temperature is higher than 650℃, it can be reduced by H2, and it can be reduced by C to obtain tungsten powder at 1000~1100℃.
How to prepare tungsten oxide
Ammonium tungstate method tungsten concentrate is alkaline hydrolyzed by sodium hydroxide, neutralized with hydrochloric acid, and then reacted with ammonium chloride to generate ammonium tungstate, and then hydrochloric acid is added for acid hydrolysis to generate tungstic acid, which is then decomposed and crushed by roasting, Get tungsten trioxide.
Hydrochloric acid decomposition of tungstate. The saturated aqueous solution of tungstate such as sodium tungstate Na2WO4 and calcium tungstate CaWO4 is heated, and the solution is slowly added dropwise to 2 to 3 times the excess boiling concentrated hydrochloric acid by mole. According to the above reaction, yellow tungstic acid is precipitated. At this time, if the dropping speed is too fast or the liquid temperature drops, suspended or colloidal precipitates are easily formed, which will bring difficulties to the next step. After dripping, heat continuously on the water bath for 1 hour, and the precipitate becomes easy to filter. After standing, it was washed several times with 5% ammonium nitrate aqueous solution to completely remove Cl-. After filtration, it is dried at 120°C and finally heated to 600°C tungstic acids are completely dehydrated into tungsten trioxide.
Thermal decomposition of ammonium para tungstate. Put ammonium para tungstate (NH4)10W12O41·11H2O purified by recrystallization into a porcelain crucible, and when heated to above about 400℃, ammonia volatilizes to obtain tungsten trioxide.
Application fields of tungsten oxide
Tungsten trioxide is used for many purposes in daily life. It is often used in industrial X-ray screen phosphors and fireproof fabrics to manufacture tungstate. Due to its abundance of yellow elements, tungsten oxide is also used as a pigment in ceramics and paints.
Tungsten trioxide has been employed in the production of electrochromic windows and smart windows. These windows are the glass of the electric switch, the light transmission performance, and the change of the applied voltage. This allows users to tint their windows through changes in the amount of heat or light. Another use is to use high-density inert metal explosives. The use of these devices is more significant in the 2008-2009 conflict between Israel and the Gaza Strip.
Part of tungsten oxide is used to produce chemical products, such as paints and coatings, petroleum industry catalysts, etc.; but tungsten oxide is an intermediate product, and a large amount of tungsten oxide is used in metal tungsten powder and tungsten carbide powder, and then used in the production of metal tungsten products Tungsten alloy products, including tungsten copper, tungsten nickel, tungsten nickel-iron, tungsten silver, tungsten rhenium, tungsten thorium, etc., are widely used in the production of tungsten alloy products, and tungsten is the most widely used substrate in contemporary industrial fields. Cemented carbide products of various grades and uses are produced.
Is tungsten oxide harmful?
Tungsten oxide is gas-sensitive and is used to detect toxic gases such as nitrogen dioxide and ammonia. Tungsten oxide thin film gas sensors and tungsten oxide nanoparticle sensors have been prepared. The discovery of nanosensors has greatly improved the detection of low-concentration toxic gases.
Tungsten trioxide Supplier
TRUNNANO (aka. Luoyang Tongrun Nano Technology Co. Ltd.) is a trusted global chemical material supplier & manufacturer with over 12 years of experience in providing super high-quality chemicals and Nanomaterials. Currently, our company has successfully developed a series of materials. The Tungsten trioxide produced by our company has high purity, fine particle size, and impurity content. For the latest price of tungsten trioxide, send us an email or click on the needed products to send an inquiry.
 

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