Recovery of the rare earth element

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PROBLEM TO BE SOLVED : To provide a recovering process which recovers a useful rare earth element from a rare earth element-iron based alloy, improves the handlability of a by-produced iron residue and decreases the amount of the produced iron residue. SOLUTION : This recovering process includes : heating a slurry prepared by mixing the rare earth element-iron based alloy with an aqueous alkaline solution while blowing air therein to convert the rare earth element to its hydroxide and the iron to triiron tetraoxide; and filtering the resultant slurry. The filtrate is reused as the aqueous alkaline solution for next treatment. The recovering process further includes : adding water to the separated solid matter to make it slurry; adding an acid to the slurry preferably while blowing air therein to leach the rare earth element with the acid; after the leaching operation has been completed, filtering the resultant slurry; and recovering the solution in which the salt of the rare earth element dissolves, and the solid residue containing triiron tetraoxide as a main component. COPYRIGHT : (C)2010, JPO&INPIT