Method for preparing dichromium trioxide from chromate

The invention relates to a method for preparing dichromium trioxide from chromate. The method adopts chromate as a raw material, adopts carbon-containing reducing gas as a reducing agent, the chromate is reduced at a temperature of 125 to 780 DEG C to obtain a reduction product consisting of dichromium and carbonate, the carbonate in the reduction product is dissolved in water, a dichromium trioxide product is obtained by virtue of filtering, washing and drying, and the carbonate in the dissolving solution is recycled by virtue of the acidification separation of CO2. By adopting the method, not only is the production process of the dichromium trioxide greatly simplified, but also the production cost of the dichromium trioxide is remarkably decreased, and the zero emission of waste water and waste slag in the entire process can be realized. The method has the advantages of short process route, low processing cost, good product quality, high efficiency, environmental protection and the like and is suitable for the industrialized production of the dichromium trioxide.