Method of recovering rare earths from a solid mixture containing a halophosphate and a rare earth compound and solid mixtures suitable for this method
AssigneeRhodia Operations
InventorsJean-Jacques Braconnier, Alain Rollat
Life of this patent
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Abstract
An acid treatment, in a liquid medium, of a solid containing a halophosphate and a rare earth compound is described. Further described, is the addition of a base to the medium obtained previously and separation of a solid phase from a liquid phase; mixing and calcination of the solid obtained previously with an alkaline solid compound; redispersing the calcined product in water, separation of the solid product from the suspension obtained in the preceding step; dispersing this solid in water and acidification of the dispersion and separation of the solid from this dispersion.
Claims4
A method of recovering rare earths from a solid mixture containing at least one halophosphate and at least one compound of one or more rare earths, the method comprising the following steps:
- (a) carrying out acid treatment of said mixture in a liquid medium having a pH;
- (b) adding a base to the liquid medium so as to raise the pH of said liquid medium to a value of at least 1.5, thus obtaining a first solid phase comprising one or more rare earths at least partly as a phosphate and a first liquid phase comprising at least one alkaline-earth element of halophosphate and separating the first solid phase from the first liquid phase;
- (c) mixing the first solid phase with an alkaline solid compound to form a resultant mixture and calcining the resultant mixture to form a calcined product;
- (d) redispersing the calcined product in water to form a first resultant suspension;
- (e) separating a second solid phase comprising one or more rare earths at least partially as a hydroxide and a second liquid phase comprising at least one alkaline element from the first resultant suspension;
- (f) dispersing the second solid phase in water to form a second resultant suspension and acidifying the second resultant suspension;
- and
- (g) separating a third solid phase and a third liquid phase comprising at least one rare earth salt from the second resultant suspension.
Dependencies are inferred from the claim text.