Processes for selective recovery of rare earth metals present in acidic aqueous phases resulting from the treatment of spent or scrapped permanent magnets

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• A method for selective recovery of at least one rare earth metal TR1 having an atomic number at least equal to 62 from an acid aqueous phase A1, the aqueous phase A1 stemming from a processing of spent or scrapped permanent magnets and comprising one or more rare earth metals TR1, transition metals and a strong acid having a concentration from 0.2 mol/L to 6 mol/L, which method comprises:
• a) extracting the rare earth metal TR1 from the aqueous phase A1, the extraction comprising putting the aqueous phase A1 in contact with an organic phase not miscible with water, which comprises a diglycolamide having a total number of carbon atoms at least equal to 24 as an extractant, in an organic diluent, and then separating the aqueous and organic phases;
• b) washing the organic phase stemming from a), the washing comprising putting the organic phase in contact with an acid aqueous phase A2 which comprises a strong acid identical with the strong acid of the aqueous phase A1, at a concentration at most equal to the strong acid concentration of the aqueous phase A1, and then separating the aqueous and organic phases;
• and
• c) stripping the rare earth metal TR1 from the organic phase stemming from b), the stripping comprising putting the organic phase in contact with an acid aqueous phase A3 which has a pH at least equal to 3, and then separating the aqueous and organic phases.

A method for selective recovery of at least one rare earth metal TR1 having an atomic number at least equal to 62 and of at least one rare earth metal TR2 having an atomic number at most equal to 61 from an acid aqueous phase A1, the aqueous phase A1 stemming from a processing of spent or scrapped permanent magnets and comprising one or more rare earth metals TR1, one or more rare earth metals TR2, transition metals and a strong acid having a concentration from 0.2 mol/L to 6 mol/L, which method comprises:

• recovery of the rare earth metal TR1 from the aqueous phase A1, which recovery comprises:
• a) extracting the rare earth metal TR1 from the aqueous phase A1, the extraction comprising putting the aqueous phase A1 in contact with an organic phase not miscible with water, which comprises a diglycolamide having a total number of carbon atoms at least equal to 24 as an extractant, in an organic diluent, and then separating the aqueous and organic phases;
• b) washing the organic phase stemming from a), the washing comprising putting the organic phase in contact with an acid aqueous phase A2, which comprises a strong acid identical with the strong acid of the aqueous phase A1, at a concentration at most equal to the strong acid concentration of the aqueous phase A1, and then separating the aqueous and organic phases;
• and
• c) stripping the rare earth metal TR1 from the organic phase stemming from b), the stripping comprising putting the organic phase in contact with an acid aqueous phase A3 which has a pH at least equal to 3, and then separating the aqueous and organic phases;
• and
• recovery of the rare earth metal TR2 from the aqueous phase at stemming from a), which recovery comprises:
• d) extracting the rare earth metal TR2 from the aqueous phase stemming from a), the extraction comprising putting the aqueous phase in contact with a second organic phase not miscible with water, which comprises an extractant identical with the extractant of the first organic phase, in an organic diluent, and then separating the aqueous and organic phases;
• e) washing the organic phase stemming from d), the washing comprising putting the organic phase in contact with an acid aqueous phase A4, which comprises a strong acid identical with the strong acid of the aqueous phase A1, at a concentration at most equal to the strong acid concentration of the aqueous phase stemming from a), and then separating the aqueous and organic phases;
• and
• f) stripping the rare earth metal TR2 from the organic phase stemming from e), the stripping comprising putting the organic phase in contact with an acid aqueous phase A5 which has a pH at least equal to 3, and then separating the aqueous and organic phases.

A method for selective recovery of at least one rare earth metal TR1 having an atomic number at least equal to 62 and of at least one rare earth metal TR2 having an atomic number at most equal to 61 from an acid aqueous phase A1, the aqueous phase A1 stemming from a processing of spent or scrapped permanent magnets and comprising one or more rare earth metals TR1, one or more rare earth metals TR2, transition metals and a strong acid having a concentration from 0.2 mol/L to 6 mol/L, which method comprises:

• a) extracting the rare earth metal TR1 and the rare earth metal TR2 from the aqueous phase A1, the extraction comprising putting the aqueous phase A1 in contact with a first organic phase not miscible with water, which comprises a diglycolamide having a total number of carbon atoms at least equal to 24 as an extractant, in an organic diluent, and then separating the aqueous and organic phases,
• b) washing the organic phase stemming from a), the washing comprising putting the organic phase in contact with an acid aqueous phase A2, which comprises a strong acid identical with the strong acid of the aqueous phase A1, at a concentration at most equal to the strong acid concentration of the aqueous phase A1, and then separating the aqueous and organic phases;
• b′) stripping the rare earth metal TR2 from the organic phase stemming from b), the stripping comprising putting the organic phase in contact with an acid aqueous phase A5, which has a pH from 1 to 2.3, and then separating the aqueous and organic phases;
• b″) washing the aqueous phase stemming from b′), the washing comprising putting the aqueous phase in contact with a second organic phase not miscible with water, which comprises an extractant identical with the extractant of the first organic phase, in an organic diluent, and then separating the aqueous and organic phases;
• c) stripping the rare earth metal TR1 from the organic phase stemming from b′), the stripping comprising putting the organic phase in contact with an acid aqueous phase A3 which has a pH at least equal to 3, and then separating the aqueous and organic phases.