METHOD FOR OBTAINING CHROMOXIDHYDRATE (CHROMIUM (III) OXYDRYDRATE) FROM CHROMERZ

摘要

There is disclosed a method for the recovery of chrome hydrate or high purity Cr2O3 from chromium ores by roasting the ore with Na2CO3 and CaO, water leaching the roasted mass, precipitating aluminium impurities from the leach liquor as Al(OH)3 and contacting the leach liquor with sulfur and NaOH in order to reduce the chromium values in the leach liquor from valence 6 to 3 to provide a chrome hydrate precipitate. The chrome hydrate precipitate may be acid repulped if it is desired to provide a chrome hydrate from which sodium impurities have been removed. If high purity Cr2O3 is required the chrome hydrate is dried and the resulting solids are calcined.