Tungstic Acid Introduction

tungstic acid picture

Tungstic acid is the general term of all kinds of hydrates of tungsten trioxide (WO3), polymer compound which formed by the combination of tungsten trioxide WO3 and then united with water at different ratios and formations. The known forms of tungstic acid are yellow, white tungstic acid and metatungstic acid, wherein the representative of yellow tungstic acid introduction is as follows:
Product Name: Tungstic Acid or Yellow Tungstic Acid
Chemical Formula: H2WO4
Monocular Mass: 249.86
CAS Number: 7783-03-1
Appearance: Yellow powder
Density: 5.59g/cm3
Solubility (Water): insoluble, but slightly dissolved in hot water
Solubility (Other solvent): dissolved in alkali and ammonia water, and hardly dissolved in inorganic acid except for hydrofluoric acid.
HS Code: 2825901100
Boiling Point: 1473℃
Melting Point: Tungstic acid will lose one molecule of water and become tungsten acid anhydride (Tungsten trioxide) when heated to 100℃.
Application: Mainly used for manufacturing metal tungsten, tungsten wire, tungsten carbide, tungstate ect., and also can be used as printing and dyeing auxiliaries, catalysts and so on.

Tungstic Acid Specification

Tungstic acid component table is showed as the following table:

Chemical Property of Tungstic Acid

Chemical property of tungstic acid is the property which is shown through chemical change, as following:
Thermal stability: Stable under normal temperature and pressure, when it is heated to 100°C~110°C, tungstic acid will lose molecule of complex water and converted to yellow tungsten oxide;
Flammablity: Non-combustible;
Stability: Stable in water and inorganic acid, but comes out a reaction quickly once it touches hydrofluoric acid, soluble in alkali solution;
Photosensitivity: White tungsten acid has slightly light sensitivity, and easy to be restored.

Chemical reaction:
1. White tungsten acid will react with strong acid (But for hydrofluoric acid) to generate yellow tungstic acid which is insoluble in water;
2. The tungsten acid reacts with phosphoric acid or phosphate to generate phosphorus tungsten heteropoly acid complex;
3. Tungsten acid reacts with tartaric acid, citric acid, oxalic acid and organic acid to generate organic acid complex.

Application of Tungstic Acid

Tungstic acid is an important chemical raw material which can be used for producing metal tungsten, tungsten wire, tungsten carbide, tungstate ect.; also it can be used as mordant, pigment, dyestuff, printing ink, catalysts, etc.; at the same time, tungstic acid can be used for the manufacturing of fire retardant rayon and spun rayon, oil industry and aviation and aerospace materials, etc..