Blue tungsten refers to a class of dark blue compounds containing mixed valence states of tungsten (ⅵ) and tungsten (V). It usually forms in solution. Preparation of pure tungsten compound using ammonium paratungstate, tungsten trioxide and sodium tungstate solution as raw materials.
Blue tungsten refers to a class of dark blue compounds containing mixed valence states of tungsten (ⅵ) and tungsten (V). It usually forms in solution. Tungsten blue was obtained from suspension of tungsten oxide in hydrochloric acid by zinc reduction.
In addition, wet tungsten oxide under ultraviolet light and white gel tungstic acid under indirect sunlight will produce blue.
Blue tungsten was prepared by pure tungsten compound with ammonium paratungstate, tungsten trioxide and sodium tungstate solution as raw materials. Blue tungsten in industry refers to a mixture of WO2.72, WO2.90, W20O58, (NH4) x· WO3, etc. The latter is ammonium tungsten bronze (ATB), a non-stoichiometric compound. Blue tungsten with ATB and WO2.90 as the main phases is a high quality raw material for tungsten production, and blue tungsten is also a good raw material for tungsten base carbide and other tungsten products.
Blue tungsten can be prepared by fire and wet methods.
fire
Fire is an industrial method. It is generally prepared from ammonium paratungstate (APT) by thermal decomposition or mild reduction with hydrogen. Blue tungsten can also be prepared by slightly reducing WO3 with hydrogen, but the quality is not as good as that of APT.
Blue tungsten used for doping in industrial production is usually obtained by mild reduction of APT with hydrogen in a four-tube or 11-tube electric furnace. The chemical composition of blue tungsten is WO2.88 ~ WO2.92. , containing 0.3% ~ 0.8% NH3.
wet
Wet method is a new method of research and development. Blue tungsten with the composition of 3.5(NH4)2O·5WO2·13WO3·4.5H2O was prepared by reducing ammonium tungstate solution with hydrogen. Blue tungsten with O: W=2.82 can be obtained by hydrogen reduction of organic phase of tungsten. Blue tungsten with WO2.90 as main phase was obtained by internal reduction method.
Main applications:
1. Materials for the gas sensor
2. Solar sensitive film
3. Premium pigments
4. The catalyst
5. X-ray shielding and fireproof fabric
