| 简介 |
The present invention concerns a method for selectively recovering the rare earths from an aqueous acid sulphate solution comprising phosphates, aluminium and heavy rare earths, and possibly medium rare earths, iron (II) and titanium, characterised in that it comprises the following successive steps : a) neutralisation, to a pH of between 3 and 4, of an aqueous acid sulphate solution comprising phosphates, aluminium and heavy rare earths, and optionally medium rare earths, iron (II) and titanium, the solution having a Al/P molar ratio > 1 and a concentration of sulphates > 100 g/L by adding a base, so as to precipitate the phosphate and the aluminium and the possible titanium, b) liquid/solid separation of the precipitate formed by the phosphate and the aluminium and the possible titanium and the aqueous sulphate solution, c) recovery of the aqueous sulphate solution, d) addition of phosphates to the aqueous sulphate solution obtained in step c) such that the molar ratio of the obtained solution P04/TR is > 4, so as to precipitate the heavy rare earth phosphates and possible medium rare earth phosphates, e) liquid/solid separation of the precipitate formed by the heavy rare earth phosphates and possible medium rare earth phosphates and the aqueous sulphate solution, f) recovery of the precipitate formed by the heavy rare earth phosphates and possible medium rare earth phosphates. |
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