METHOD OF PRODUCING CHROMIUM OXIDE Russian patent published in 2019 - IPC C01G37/02 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry and can be used for production of metal chromium. Ammonium sulphate is dissolved in water to obtain concentration of 35–50.4 % (NH₄)₂SO₄. Sodium bichromate is dissolved in ammonium sulphate solution at temperature of 90–100 °C for 15–40 minutes with constant stirring to produce ammonium dichromate and sodium sulphate. Obtained reaction mass in the form of an aqueous suspension is subjected to heat treatment at temperature of 235–400 °C before decomposition of ammonium dichromate. Ammonium dichromate decomposition products are washed from water soluble substances and subjected to repeated heat treatment at 800–1,400 °C until formation of chromium oxide.

EFFECT: simplified process, high purity of chromium oxide Cr₂O₃ up to 99,3 % due to reduced content of impurities and increased particle size.

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