METHOD FOR ISOLATING RARE EARTHS AND/OR ADJACENT METAL ELEMENT(S) CONTAINED IN THE MAGNETIC PHASE OF

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The present invention relates to a method which is useful for isolating rare earths and/or adjacent metal element(s) other than the rare earths contained in the magnetic phase of magnets or by-products, including at least the steps of : (i) arranging the material forming said magnetic phase in the form of a demagnetised powder, having an average particle size no larger than 700 µm and free of contamination with particles that do not make up said magnetic phase; (ii) dissolving said powder of step (i) in an acid medium supplemented with at least one oxidising agent suitable for adjusting the adjacent metal element(s) to a state of oxidation that is compatible with the subsequent precipitation thereof in step (iii), in the presence of hydroxide ions, at a pH strictly lower than 7; (iii) precipitating the adjacent metal element(s) in the hydroxide state by means of adding to said solution obtained at the end of step (ii) an effective amount of at least one hydroxylated base, in pH conditions that are suitable for maintaining the rare earth elements in solubilised form; (iv) isolating the metal hydroxide precipitate formed at the end of step (iii) and, when necessary, recovering same; (v) precipitating the rare earth elements in the oxalate state in the solution that is depleted of or free of adjacent metal element(s) and obtained at the end of step (iv), by adding an effective amount of oxalic acid to said solution; and (vi) recovering said rare earths in the precipitated state of rare earth oxalate.