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 WO3.H2O, 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.
Yellow tungsten oxide is a finely divided, yellow crystalline powder. It is produced by roasting ammonium paratungstate at closely controlled temperatures to drive off water and ammonia. Exact time and temperature control determine, to a large extent, the physical characteristics of yellow tungsten oxide.