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…
Tungsten Oxide
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…
95% ultrafine violet tungsten oxide’s morphology shows some aggregates, which are mainly composed of cluttered columnar or needle-shaped crystals. These aggregates are uneven in thickness, but have an aspect ratio of 20 or above. The morphology of violet tungsten oxide maintains the crystal form like the APT’s. The figure above shows the morphology of single particle of violet tungsten oxide after ultrasonic dispersion. It can be seen from the figure that long needle-like particle in violet tungsten oxide have broken…
High-purity ultrafine grain size violet tungsten oxide may shield light waves from the near-infrared light. In other words, it may insulate heat intelligently. Also, violet tungsten oxide may be used as drug carrier to treat cancer in the field of biomedicine. Besides, it may be applied in photocatalytic degradation of organic pollutants to clean up environment. Monoclinic violet tungsten oxide has the largest degree of oxygen vacancy. Compared with yellow tungsten oxide and blue tungsten oxide, violet tungsten oxide has…
Ultrafine grain size violet tungsten oxide may be prepared by different production processes. At present, violet tungsten oxide (VTO) is generally produced by using ammonium paratungstate (APT) as raw material, and calcining APT with the injection of ammonia gas (NH3) in a rotary furnace. However, the VTO powder prepared by this method has large particle size and high impurity content, that is, it is difficult to obtain VTO powder with higher purity. Research also shows that a method for preparing…
95% nano grain size violet tungsten oxide has the advantages of large specific surface area, large surface activity, and so on. The nano grain size violet tungsten oxide may be prepared by the following steps: 1. Weigh 0.01mol of ammonium metatungstate ((NH4)6H2W12O41), 0.24mol of ammonium nitrate (NH4NO3) and 0.05mol of thiourea (CN2H4S) in accordance with stoichiometry. 2. Dissolve these raw material powders in an appropriate amount of deionized water and stir until completely dissolved. 3. The above solution was heated…
High-purity nano violet tungsten oxide may by prepared by the following steps: Step one: Adopt ammonium metatungstate (AMT), ammonium nitrate (NH4NO3) and adjuvant as raw materials. Step two: Prepare these raw materials into solutions according to a certain molar ratio. Mix the solutions evenly. The molar ratio of NH4NO3 to AMT is 12~36. The molar ratio of adjuvant to AMT is 5~15. Step three: The above solutions is heated to be evaporated and condensed to form gelatinoids, and decomposition reaction…