Use of synergistic mixture of extractants for extracting rare earth elements from an aqueous medium comprising phosphoric acid

A method for extracting at least one rare earth E1 selected from lanthanum, cerium, praseodymium and neodymium together with at least one rare earth E2 selected from samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium, from an aqueous medium comprising phosphoric acid, the aqueous medium resulting from the lixiviation of a phosphate ore by sulfuric acid and comprising, further to the rare earths E1 and E2, metallic impurities including iron, the method comprising:

• contacting the aqueous medium with an organic solution which is not miscible with water and which comprises a mixture of extractants comprising:
• a first extractant of formula (I):
• wherein R1 and R2, the same or different, represent a saturated or unsaturated, linear or branched hydrocarbon group comprising from 6 to 12 carbon atoms, or a phenyl group, optionally substituted by a saturated or unsaturated, linear or branched hydrocarbon group comprising from 1 to 10 carbon atoms;
• and
• a second extractant or formula (II):
• wherein R3 represents a linear or branched alkyl group, comprising from 6 to 12 carbon atoms;
• and then:
• separating the aqueous medium from the organic solution comprising the mixture of extractants, whereby the at least one rare earth E1 and the at least one rare earth E2 are present in the organic solution.