Method for producing powder in micron order of bismuth oxide

This invention discloses a method for preparing high-purity bismuth oxide micropowder. The method comprises: dissolving bismuth in nitric acid to obtain bismuth nitrate, filtering, adding ammonia solution into the bismuth nitrate solution to synthesize bismuth subnitrate, hydrolyzing, centrifuging, and dry-filtering, heating and pulverizing by a gas flow pulverizer to obtain high-purity bismuth oxide micropowder. During bismuth subnitrate synthesis, uniform particle sizes of bismuth subnitrate can be realized by controlling the concentration and flow rate of ammonia solution, as well as the concentration and synthesis temperature of bismuth nitrate solution. The method has such advantages as no need for dispersant, simple process, low requirement for apparatus, and low energy consumption.