| 摘要 |
A process is disclosed for recovering chromium from a chromium bearing material containing cobalt, molybdenum, and tungsten. The process involves roasting the material and alkali metal compound at a temperature of at least about 400 DEG C. for a sufficient time to react the alkali metal compound with the material and form a reacted mixture containing essentially all of the chromium, molybdenum, and tungsten as alkali salts. The reacted mixture is water leached to dissolve the alkali salts and form a leach solution containing essentially all of the chromium, molybdenum, and tungsten, and a leach solid containing essentially all of the cobalt. After separation of the leach solution from the leach solid, the pH of the leach solution is adjusted to from about 0.5 to about 3.0 with an acid and a sufficient amount of a reducing agent is added to reduce essentially all of the chromium to the trivalent state. A precipitating agent is added to precipitate essentially all of the molybdenum and tungsten values while leaving essentially all of the reduced chromium values in the mother liquor, while the pH is maintained at from about 0.5 to about 3.0. The precipitate is separated from the mother liquor. A sufficient amount of ammonium sulfate is added to this mother liquor to precipitate essentially all of the chromium contained therein.
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