The physical and chemical properties of tungsten oxide and its preparation method
Tungsten trioxide is a powder metallurgical raw material for the production of cemented carbide and tungsten products. According to the national standard (GB/T 3457-1998), it is divided into two types: tungsten trioxide (yellow tungsten for short), with the molecular formula WO3, and blue tungsten oxide (blue tungsten for short, which is a mixed tungsten oxide). W20O58. Yellow tungsten is light yellow crystalline powder, and blue tungsten is dark blue or blue-black crystalline powder. The physical and chemical properties of tungsten oxide Tungsten trioxide is a light yellow triclinic powder crystal. When the temperature is higher than 740°C, it turns into orange tetragonal crystals, and returns to the original state after cooling. It is stable in the air, the melting point is 1473°C, the boiling point is higher than 1750°C, and the relative density is 7.16. Tungsten trioxide is the most stable kind of tungsten oxide. It is insoluble in water and inorganic acids except hydrofluoric