Tungsten Oxide

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Crystalline Ammonium Metatungstate 531

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…

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Hollow Ammonium Metatungstate Sphere 544

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…

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High-purity Ammonium Metatungstate 546

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:…

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Ammonium Metatungstate Microsphere 579

Ammonium metatungstate microsphere may be prepared by two different spray drying methods. Ammonium metatungstate (AMT) is usually used as one of the precursors of tungsten carbide (WC) catalysts. And the morphology and particle size distribution of WC microsphere are affected by the properties of precursor. In other words, AMT properties will have an important influence on morphology and particle size distribution of WC microsphere and have a finally effect on the catalytic activity of WC catalyst. Therefore, it is necessary…

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Ammonium Metatungstate Solution 359

Ammonium metatungstate solution is an aqueous solution of ammonium metatungstate (AMT), which may be prepared using ammonium tungstate solution as raw material by Bipolar Membrane Electrodialysis (BMED). AMT solution may be used as raw material for producing its downstream products by liquid phase process. AMT is extremely easily soluble in water, and its solubility in water increases with the increase of temperature. BMED is a new membrane separation technology, which has been widely applied in the preparation of acid, alkali,…

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Chromium Doped Ammonium Paratungstate 567

Chromium doped ammonium paratungstate may be produced by doping chromium (Cr) in evaporation crystallization process during the production of ammonium paratungstate. Adopting chromium acetate (CH3COO)3Cr (analytical reagent) and ammonium tungstate solution obtained by dissolving high-purity WO3 with ammonia water as raw materials to study the process of preparing APT powder by adding chromium acetate during crystallization. The result showed that: 1. Chromium mainly precipitated in the precipitation form of Cr(OH)3, which is prior to ammonium paratungstate, and the pH value…

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Arsenic Doped Ammonium Paratungstate 593

Arsenic doped ammonium paratungstate may be prepared by adopting simple arsenic, nitric acid solution and ammonium paratungstate (APT) as raw materials and forming in liquid phase, the preparing steps are as below: 1. Dissolve a certain amount of simple arsenic (As) in the nitric acid solution with a certain concentration until it completely dissolves; 2. Add APT powder into the nitric acid solution of simple arsenic, and control the content of arsenic in a certain value; 3. After completely mixing…

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Sodium Doped Ammonium Paratungstate 577

Sodium doped ammonium paratungstate may be used to prepare coarse grain size tungsten trioxide (WO3), and the content of sodium (Na) may affect the particle size of tungsten (W) powder prepared by WO3. APT with high sodium content may be calcined to produce high sodium content of WO3 powder – an upstream raw material for preparing coarse grain size tungsten powder, which is a raw material for tungsten carbide with coarse grain size. And tungsten carbide with coarse grain size…

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Coarse Ammonium Paratungstate 636

Coarse ammonium paratungstate has advantages of large apparent density and good fluidity, and its demand increases year by year as customers are requiring more and more strictly on the performance of subsequent products now. Preparation of Coarse Ammonium Paratungstate 1. Experimental solution and equipment: (1) Adopt (NH4)2WO4 solutions produced by classical process and ion exchange process as test material liquid; Part of the solution was prepared by diluting ammonia water. (2) A 1500L open type enamel reactor equipped with an…

Product
Super Grade Ammonium Paratungstate (APT-0) 730

Super grade ammonium paratungstate is ammonium paratungstate with grade of APT-0, which is divided by national standard. Generally, traditional process to prepare high-purity ammonium paratungstate is first to dissolve super grade ammonium paratungstate by ammonia-dissolving method, and then evaporation recrystallization. The high-purity APT produced by traditional process has the disadvantages as follows: The energy consumption is high and the comprehensive recovery rate of resources is low. Also, equipment and investment are increased when compared with new processing technology, so that…

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