METHOD FOR PREPARING RARE EARTH ELEMENT SOLUTION

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PROBLEM TO BE SOLVED : To prepare a method for preparing a rare earth element solution allowing for reduction in an amount of an organic solvent to be used, downsizing of an apparatus, and reduction in a workload of processing in separating a light rare earth element from a heavy rare earth element by solvent extraction. SOLUTION : The method for preparing a rare earth element solution comprises the steps of : (1) obtaining a mixture of a compound oxide or an oxide of a light rare earth element and a heavy rare earth element from a processing object including both elements; (2) dissolving the obtained mixture of the compound oxide or the oxide in hydrochloric acid and/or nitric acid; (3) obtaining a precipitate by adding a precipitant to the obtained solution; (4) burning the obtained precipitate; (5) adding the obtained burned product in an amount of 1.5 or more times its solubility to a mixed acid of at least one inorganic acid selected from hydrochloric acid and nitric acid of a concentration of 0.7 mol/L or more and at least one organic acid selected from acetic acid, citric acid, lactic acid, acetylacetone acid, and α-hydroxyisobutyric acid thereby obtaining a rich solution of the light rare earth element and a rich residue of the heavy rare earth element; and (6) separating the obtained solution from the residue. SELECTED DRAWING : Figure 1 COPYRIGHT : (C)2018, JPO&INPIT