Tungsten Trioxide Preparation
Tungsten trioxide can be prepared in several different ways. CaWO4, or scheelite, is allowed to react with HCl to produce tungstic acid, which decomposes to WO3 and water at high temperatures.
CaWO4 + 2HCl → CaCl2 + H2WO4
H2WO4 + heat → H2O + WO3
Another common way to synthesize WO3 is by calcination of ammonium paratungstate (APT) under oxidizing conditions:
(NH4)10[H2W12O42]?4H2O → 12 WO3 + 10NH3 + 10H2O
Related Products:
Ammonium paratungstate (APT) is an important intermediate compounds of tungsten hydrometallurgical process, appearance is white crystalline powder, insoluble in water, soluble in alcohol and ether.
Ammonium metatungstate(AMT) is an important intermediate compounds of tungsten hydrometallurgical process, appearance is white crystalline powder, solubility in water is the largest in the tungsten compounds which over 300g WO3/100ml H2O (in 25℃).
Sodium tungstate, a tungstate of sodium, is useful as a source of tungsten. It is prepared from tungsten ores used to manufacture tungsten by reducing it.
Tungstic acid refers to hydrated forms of tungsten trioxide, WO3. The simplest form, the monohydrate, is WO3H2O, the dihydrate WO3·2H2O is also known. The solid state structure of WO3· H2O consists of layers of octahedrally coordinated WO5(H2O) units where 4 vertices are shared.
Blue tungsten oxide refers to a class of dark blue compound containing tungsten (Ⅵ) and tungsten (V) mixed valence state. Blue tungsten oxide is the product of reductant and tungsten compounds. Composition of blue tungsten oxide is complex, among which there are also intermediate oxides like WO2 and W4.
Cesium tungsten bronze is inorganic nano material with good property in absorbing near-infrared with uniform grain size and dispersibility, it has strong absorbing function in near-infrared area with wave length 800~1200nm, also has high transmittance in visible light area with wave length 380~780nm.