Process for the Recovery of Rare Earth Elements

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ABSTRACT A process for recovering rare earth elements from a composite ore or concentrate that includes at least apatite group minerals, as well as at least one other rare earth containing mineral, the process including : a. subjecting the ore or concentrate to a sulphuric acid pre-leach to form a pre leach liquid phase and a pre-leach solid phase, the pre-leach liquid phase containing dissolved phosphates and dissolved rare earth elements, and the pre leach solid phase containing sulphuric acid-insoluble minerals and calcium sulphate precipitate; b. mixing the pre-leach solid phase with sulphuric acid and baking the mixture at a temperature in the range of 200 to 3000C to produce an acid-baked solid phase; and c. subjecting the acid-baked solid phase to a water leach, in water and/or in the pre-leach liquid phase, to dissolve rare earth elements in the acid-baked solid phase to form a water-leach liquid phase and a water-leach solid phase; wherein the water-leach liquid phase is at least partly recycled to the pre-leach and rare earth elements are recovered from the pre-leach liquid phase; and/or the water-leach liquid phase is not recycled to the pre-leach and rare earth elements are recovered from the water-leach liquid phase. LTL I - on; > L Ufr. ~ LL A A *1 I : I V1, ~