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US 5,030,424 AGranted
Recovery of rare earth elements from Bayer process red mud
AssigneeAlcan International Limited
InventorsGeorge D. Fulford, Gordon Lever, Taichi Sato
Life of this patent
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Abstract
A process for the recovery of rare earth elements from Bayer Process red mud includes the following steps: (a) digesting red mud containing rare earth elements with a dilute acid solution, e.g. sulphur dioxide dissolved in water, to selectively dissolve the rare earth elements while leaving iron in the red mud substantially undissolved; (b) separating the solution obtained from the solid residue and (c) recovering the rare earth elements from the solution.
Claims22
A process for the recovery of rare earths from Bayer process red mud which comprises:
- (a) digesting red mud containing rare earths together with iron, sodium, calcium, alumina and silica values in a dilute mineral acid solution to obtain a final digestion slurry having a pH of about 1.8 to 3 whereby rare earths are selectively dissolved while leaving iron in the read mud substantially undissolved;
- (b) separating the solution obtained containing rare earths from the remaining insoluble components, and
- (c) recovering the rare earth elements from said solution.
Dependencies are inferred from the claim text.