METHOD OF RECOVERING ALKALI METAL CHROMATE Russian patent published in 1999 - IPC

FIELD: technology of preparing chromates. SUBSTANCE: alkali metal chromate is prepared by alkaline oxidizing treatment of chromium ore in oxygen-containing atmosphere at 850-1150 C, leaching of the resulting cake with water or aqueous chromate-containing solution, separation of insoluble components by filtration from the resulting solution and isolation of final product. Oxygen- containing gas is fed into layer of reaction mixture through underlayer nozzles located along at least one circumference in plane which is vertical to axis of rotating tubular furnace and which extend through its lateral surface. Oxygen-containing gas is fed along circumference through 6-20 nozzles located at uniform distance in zone which is third part of rotating tubular furnace. Method makes it possible to recover more economically chromate from chromium ore. EFFECT: more efficient recovery method. 3 cl, 4 dwg