| 简介 |
PROBLEM TO BE SOLVED : To provide a method for recovering rare earths where the intrusion of impurities is prevented, and a large quantity of rare earths are recovered at a low cost.
SOLUTION : The method for recovering the rare earths comprises : a first stage where rare earth magnet scrap generated in the production process of a rare earth magnet is fed to sulfuric acid, and rare earths in the rare earth magnet scrap are dissolved in the sulfuric acid; a second stage where a reducing material is fed to the sulfuric acid in which the rare earths are dissolved so as to reduce the oxidation-reduction potential of the sulfuric acid, and further, to keep pH to ≤5 with sulfuric acid for adjustment; a third stage where undissolved components are removed from the sulfuric acid obtained in the second stage so as to obtain a rare earth-containing solution; a fourth stage where the solution obtained in the third stage is crystallized so as to precipitate the sulfate of the rare earths; and a fifth stage where the crystals of the precipitated sulfate of the rare earths are recovered.
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