METHOD OF EXTRACTING OXIDES OF RARE EARTH ELEMENTS OUT OF GRINDING WASTES OF CONSTANT MAGNET PRODUCTION Russian patent published in 2009 - IPC C01F17/00 

FIELD: metallurgy.

SUBSTANCE: grinding wastes containing compounds of REE (rare earth elements) are mixed with ammonium fluoride-hydro-fluoride taken in excess to 20% from stoichiometric ratio. Mixture is heated to 230°C and conditioned at this temperature to complete separation of volatile compounds of carbon, boron and other non-metal fluorides. Solid residue of fluoride compounds of REE, silicon, aluminium and iron are heated to temperature above 320°C for sublimation separation of silicon compound. Produced solid residue is subject to water leaching for separation of iron compounds. Non-solvent fluorides of REE and aluminium are transferred into oxide form by pyro-hydrolysis and then crumbled. REE oxides are separated from aluminium oxide by magnet separation.

EFFECT: invention facilitates extraction of REE compounds purified from impurities of carbon, boron, silicon, iron and aluminium.

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