Blue tungsten oxide is also known as beta tungsten oxide. Its molecular formula is W20O58 or WO2.90, which belongs to tetragonal system. Industrial blue tungsten oxide is an industrial product containing full or partial blue tungsten oxide. It has become an important raw material for the production of high quality tungsten powder. According to different production processes, industrial blue tungsten oxide may contain yellow tungsten oxide (WO3) and / or purple tungsten oxide (W18O49 or WO2.72), and even contain trace amounts of ammonium paratungstate (APT) and / or ammonium tungsten bronze (ATB).
In the national standard "GB/T3457-1998", the provisions of blue tungsten oxide phase composition in WO2.90 should not be less than 70%, but due to the fact that the process parameters of raw material and production fluctuations, industrial blue tungsten oxide product composition may fluctuate, WO2.90 content may be less than 70% of requirements of the national standard. By X ray diffraction (XRD) method can accurately measure the phase composition of WO2.90 in blue tungsten oxide, the phase composition of the industry at present is usually measured by X ray diffraction method. Determination of industrial blue tungsten oxide and standard sample in the diffraction peak intensity of WO3 phase and WO2.72 and / or the diffraction peak size measured respectively by X ray diffraction, calculate the ratio of WO2.90、WO3 and WO2.72, then calculate the content of phase.
Blue tungsten oxide powder bulk density can be measured by bulk density meter. Particle size is determined by particle size analyzer. Impurity content is determined by HMI/ICP-MS.