Preparation process of high purity yellow tungsten oxide is as follows: adjusting pH of sodium tungstate solution to 4 ~ 8 using organic or inorganic acid. After hydrothermal reaction 12 hours, filtration, concentration, crystallization and obtained seed. Under the high pressure reaction kettle, mixed solution of crystal seed and sodium acid under 200 ~ 220℃, cooled to room temperature after 12 hours. Filtering and cleaning the reaction product of, and getting the filter cake and mother liquor. Low-temperature roasting the filter cake under 350℃, and the high purity tungsten oxide products.
Yellow tungsten oxide prepared by the above process has the characteristics of fine granularity, high purity and good stability.