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Fine grain size ammonium paratungstate may be prepared by microwave-ultrasonic cooperative evaporation crystallization at higher temperature and without addition of surfactant. A fine single crystal APT-4 with average particle size of 7.6μm, uniform particle size distribution and complete crystal form can be obtained under the following conditions: Not stirred by machinery or under magnetism; No addition of surfactants; Under better APT preparation conditions – ultrasonic frequency of 25kHz, power of 1000W, microwave power of 700W, temperature of 80°C, ammonium tungstate…

Ultrafine ammonium paratungstate is the key raw material for preparing fine grain size tungsten products with superior performance such as ultrafine tungsten powder, ultrafine tungsten carbide powder, etc. That is because the properties of tungsten products such as grain size and crystal morphology have great “inheritance” relationship with their raw material – APT. At present, APT is mainly produced by crystallization process in industry with the particle size of 25-60μm, which is difficult to meet the requirements for producing fine…

High purity ammonium paratungstate is prepared to meet higher requirements of high-end tungsten carbide materials (APT). With the development of the process technology of follow-up product, customers who have demand in high-end tungsten carbide products not only makes certain requirements on the content of impurities and physical properties of APT, but also strict requirements on the content of K, Na in APT. Why the K, Na content in APT should be well controlled? During producing tungsten oxide and tungsten powder,…

Ammonium paratungstate powder (APT) may be produced by secondary reduction process. In other words, APT is reduced to blue tungsten oxide (BTO) in first stage, and BTO is reduced to tungsten powder (W powder) in the second stage. There are two methods for reducing APT to BTO – hydrogen reduction and self-reduction. And there are also two types of blue tungsten oxide – doped blue tungsten oxide and undoped blue tungsten oxide. The W powder using undoped blue tungsten oxide…

Reagent grade ammonium paratungstate means the ammonium paratungstate that acts as a chemical reagent for analysis in experiments or research. The purity of this grade of ammonium paratungstate is relatively higher. Chemical reagent is a large class of pure chemical substances with various standard purities and can be used for education, scientific research, analysis and testing as well as dingal materials and raw materials required by some kinds of novel industrial materials. While there is still no uniform international rule…

High-purity ammonium paratungstate’s thermal decomposition refers to the process to decompose APT by heating. Thermal Decomposition of High-purity Ammonium Paratungstate APT was heated to in the temperature range of 220-280°C to lose part of ammonia and crystal water and converted into ammonium metatungstate (AMT). After being heated to above 600°C, APT was found to decompose into WO3, which lose all ammonia and crystal water. Thermal decomposition is a chemical decomposition caused by heat. The reaction is usually endothermic as heat…

AR ammonium paratungstate is the abbreviation for analytical reagent ammonium paratungstate, which is a type of chemical agent with molecular formula of H40N10O20W5 and molecular weight of 1419.57. Analytical reagent, abbreviated as AR, refers to a reagent used as a common test solution in quantitative analysis, which has high purity. In other words, the analytical reagent ammonium paratungstate has the characteristics of high content of main components and low content of impurities. Therefore, analytical reagent will not hinder analysis and…

Industrial grade ammonium paratungstate is ammonium paratungstate for industrial use, whose specific content standard is determined based on product attributes. Industrial grade ammonium paratungstate is classified in accordance with the application of ammonium paratungstate like reagent grade ammonium paratungstate. Reagent grade ammonium paratungstate, such as AR ammonium paratungstate, is commonly used in laboratories for analyzing. Generally, the purity of industrial grade ammonium paratungstate is always lower than that of reagent grade ammonium paratungstate such as AR ammonium paratungstate. There are…

88.5% ammonium paratungstate referred to the ammonium paratungstate powder with tungsten oxide content of not less than 88.5% and the remaining components as impurities such as Al, Co, Mo, Cu, Ni, and so on. Its grade is APT-0 or APT-1 according to Chinese national standards. The components of APT-0 ammonium paratungstate (main content of WO3 and others of impurities) provided by Chinatungsten Online is as follows: WO3 occupies 88.50% of total weight or even higher; Al≤0.0005%; As≤0.0010%; Bi≤0.0001%; Ca≤0.0010%; Cd≤0.0010%;…

APT is the abbreviation for ammonium paratungstate. It may be reduced to tungsten powder (W powder) by hydrogen reducing agent. There are two processes – direct reduction and secondary reduction. 1. Direct Reduction Adopt H2 to directly reduce APT to W powder. Calcination and reduction are generally completed in a furnace tube where is controlled by multiple temperature zones, and the obtained W powder has the characteristics of fine grain size and dark gray color. However, this producing method isn’t…