The English abbreviation of ammonium metatungstate is AMT, which is a white or slightly yellow crystalline powder. It is very soluble in water, and its solubility in water increases with the increase of temperature. It is insoluble in alcohol. Preparation method: Heat and thermally dissociate ammonium paratungstate to make it lose part of ammonium and crystal water to obtain ammonium metatungstate. Ammonium metatungstate is often used in the preparation of metal tungsten, high-efficiency tungsten catalysts in petrochemicals, nuclear shielding…

Cesium tungsten bronze powder may be used as transparent material with heat-insulating performance, which has wide application prospects in the field of automotive glass and window glass of building for thermal insulation. It is also energy saving. Preparation of Cesium Tungsten Bronze Powder 1. Prepare sodium tungstate solution with a concentration of 0.5mol/L using AR sodium tungstate (Na2WO4•2H2O) as raw material, and obtain tungstic acid sol by cationic resin exchange, then add AR citric acid at a concentration of 1mol/L…

Cesium tungsten bronze nanopowder may absorb infrared rays and may be used for preparing transparent heat insulation coating. Preparation of Cesium Tungsten Bronze Nanopowder 400kg of sorbitol was heated and dissolved in a jacketed reactor and tungstic acid and cesium sulfate were added. The mass ratio of tungstic acid and cesium sulfate was 1:0.33. The mass of sorbitol was 3 times the total mass of tungstic acid and cesium sulfate. Stir at high speed for 30min, and pump into a…

Doping ammonium metatungstate may be applied as a raw material for producing tungsten products with special ding. For example, potassium doped ammonium metatungstate may be used to prepare K-doped tungsten powder, which can be used for preparing tungsten filaments. Generally, doping AMT is referred as to white crystalline powder obtained by doping other elements in AMT in the liquid phase process. Nano Grain Size Tungsten Powder Prepared by Arsenic-doped Ammonium Metatungstate 1. AMT is added to nitric acid solution with…

Ammonium metatungstate hydrate is the hydrate of AMT with CAS No. of 12333-11-8, molecular formula of (NH4)6H2W12O40•xH2O, and molecular weight of 2974.3. Its WO3 content is determined to be 99.0%. Its total impurity is less than or equal to 0.005% water-insoluble substance. Ammonium Metatungstate Hydrate Properties 1. Melting point is 100°C (dec.) (lit.); 2. It is soluble in water and its solubility in water is 0.1g/mL. The solution is clear and colorless. Ammonium Metatungstate Hydrate Applications 1. Used as a…

High-purity ammonium metatungstate crystal may be prepared by neutralization-nanofiltration-crystallization coupling process. Among them, the coupling process of neutralization-nanofiltration was studied to know the effects of temperature, pH value, stirring rate, and membrane pressure on the coupling process. The neutralization-nanofiltration coupling process includes acid neutralization process to prepare AMT mixed solution and nanofiltration process of AMT mixed solution. Neutralization-nanofiltration Coupling Process to Study Preparation Conditions of High-purity Ammonium Metatungstate Crystal 1. Test Materials and Devices (1) Ammonium paratungstate (APT-0); (2) Nitric…

Industrial grade ammonium metatungstate is ammonium metatungstate of very high purity. The determination of bismuth (Bi) in AMT may be feasible by coprecipitation-hydride generation-atomic fluorescence spectrometry. A Method for the Determination of Bismuth in AMT by Coprecipitation-hydride Generation-atomic Fluorescence Spectrometry 1. Instrument AFS-830 dual channel atomic fluorescence spectrometer; bismuth high intensity hollow cathode lamp. 2. Reagents (1) Standard stock solution: 1,000 μg/mL; (2) Bismuth standard solution: 100ng/mL; (3) Reducing agent: 20g/L KBH-5g/L KOH mixed solution, which is freshly prepared just…

Crystalline ammonium metatungstate is an important intermediate compound (or raw material) for the production of tungsten products. And tungsten products are important industrial raw materials, whose impurity content should be strictly controlled and accurately detected. In recent years, the requirements for purity of AMT has become higher and higher so that more and more impurity elements should be analyzed. Among them, the determination of trace bismuth in crystalline ammonium metatungstate is available by coprecipitation-hydride generation-atomic fluorescence spectrometry. And hydride generation-atomic…

Hollow ammonium metatungstate sphere may be prepared by spray drying method. The average diameter of the hollow ammonium metatungstate ball is 1.03μm, and the wall thickness is about 100nm. The preparation process is divided into 3 stages: atomization, shell formation during flash evaporation and hollow structure formation. The initial temperature in hot air drying tower is 130°C, which is far higher than the boiling point of water, leading to rapid evaporation of droplet surface water. The fast evaporation speed leads…

High-purity ammonium metatungstate may be prepared by a coupling process of neutralization-nanofiltration-crystallization. AMT solution is obtained by neutralization-nanofiltration, which can not only reduce cost as high concentration of AMT solution is obtained for the subsequent crystallization process, but also ensure to prepare high purity AMT as the impurity content is low. In the above figure, 1. High pressure pump; 2. Primary liquid tank; 3. Nanofiltration membrane device; 4. Valve; 5. Valve. The neutralization-nanofiltration-crystallization process consists of the following three steps:…