The role of tungstic acid? Introduction to the properties and uses of tungstic acid

[Molecular formula]H2WO4

［Properties］ Tungstic acid is divided into two types: white tungstic acid (WO3·nH2O) and yellow tungstic acid (WO3·H2O). White tungstic acid is a precipitate with variable composition, which can be converted into yellow tungstic acid after prolonged boiling. Yellow tungstic acid is a compound with a certain composition. The so-called tungstic acid often refers to yellow tungstic acid, which is yellow powder or crystal, with a relative density of 5.5 and a boiling point of 1473°C. Heating to 100°C starts dehydration and turns into tungstic anhydride, and turns into tungsten trioxide by burning at high temperature. Tungstic acid is insoluble in cold water, slightly soluble in hot water, and insoluble in other inorganic acids except hydrofluoric acid, slightly soluble in concentrated hydrochloric acid, but soluble in lye and ammonia water to form the corresponding orthotungstate.

［Application］It is used in the manufacture of tungstates, metal tungsten wires, tungsten bars and hard alloys for electric light sources. Used as a catalyst in petrochemical industry. It is also used as printing and dyeing aids, mechanical lubricants, ceramic colorants, and flame retardants for fire-resistant fabrics. It is also used in the manufacture of X-ray fluorescent screens, etc.

[Brief recipe]

①In industry, generally, sodium tungstate is produced by reacting wolframite with sodium hydroxide, filtered and purified, and then undergoes metathesis reaction with calcium chloride solution , to generate calcium tungstate, and then treated with hydrochloric acid to make tungstic acid.

②Calcium tungstate can be obtained by roasting sodium carbonate and tungsten ore or calcium tungstate ore, then immersing and purifying in water, adding calcium chloride to precipitate, and then After hydrochloric acid hydrolysis in the system.

[Safety and Protection]Packed in iron or wooden drums lined with double-layer plastic bags, the net weight of each drum in iron drums is 50kg , the net weight of each barrel is 25kg. Do not contact with alkalis or co-storage and transport. Store in a cool, ventilated and dry place. In case of fire, yellow sand, water and various fire extinguishers can be used to put out the fire.

The dust is irritating to the respiratory tract and skin.