Method of direct solvent extraction of rare earth metals from an aqueous acid-leached ore slurry
A method of extracting rare metals from ore including: providing an aqueous acid-leached ore slurry; adding an organic extractive solvent to the aqueous acid-leached ore slurry; mixing an organic extractive solvent with the aqueous acid-leached ore slurry to form a mixture; and separating the mixture into at least an aqueous phase and a solvent phase. The aqueous acid-leached ore slurry may have a viscosity of less than 400 centipoise, a Newtonian or near Newtonian rheology, and a pH of less than 4.0. The organic extractive solvent may comprise an extractant, a solvent, and a modifier. Separation of the aqueous acid-leached ore slurry/organic extractive solvent mixture may result in an emulsion phase, a crud, or both in addition to the aqueous phase and the solvent phase. The emulsion phase, the crud or both may be further treated by adding a low-carbon-number alcohol.
1. A method of extracting scandium from ore comprising:
providing an aqueous acid-leached ore slurry comprising scandium and at least 0.1% solids; and
extracting the scandium from the aqueous acid-leached ore slurry, wherein the extraction of the scandium from the aqueous acid-leached ore slurry comprises:
adding an organic extractive solvent to the aqueous acid-leached ore slurry;
mixing the organic extractive solvent with the aqueous acid-leached ore slurry to form a mixture; and
separating the mixture into at least an aqueous phase and a solvent phase, wherein the solvent phase comprises the extracted scandium.
2. The method of claim 1 , wherein the aqueous acid-leached ore slurry has a viscosity of less than 400 centipoise.
3. The method of claim 1 , wherein the aqueous acid-leached ore slurry has a viscosity of less than 100 centipoise.
4. The method of claim 1 , wherein the aqueous acid-leached ore slurry has a Newtonian or near Newtonian rheology.
5. The method of claim 1 , wherein the aqueous acid-leached ore slurry has a pH of less than 4.0.
6. The method of claim 1 , wherein the aqueous acid-leached ore slurry is treated to convert ferric iron ions to ferrous iron ions prior to adding the organic extractive solvent.
7. The method of claim 1 , wherein the organic extractive solvent comprises an extractant, a solvent, and a modifier.
8. The method of claim 7 , wherein the extractant is anionic or non-ionic.
9. The method of claim 7 , wherein the extractant comprises phosphorous-containing molecules.
10. The method of claim 7 , wherein the extractant is Di-(2-ethylhexyl)-phosphoric acid or tri-butyl phosphate.
11. The method of claim 7 , wherein the solvent comprises a hydrocarbon or mixture of hydrocarbons having a boiling point of 100° C. or greater.
12. The method of claim 7 , wherein the solvent is kerosene or diesel.
13. The method of claim 7 , wherein the modifier is isodecanol, coconut alcohol, octanol, ethylhexyl alcohol, or any other alcohol containing six or more carbon atoms.
14. The method of claim 1 , wherein the mixing comprises completing a mixing-resting cycle comprising mixing for at least 3 seconds followed by turning off the mixing to allow the mixture to rest for at least two seconds and, optionally repeating the mixing-resting cycle two or more times.
15. The method of claim 1 , wherein the mixing is carried out at less than or equal to 100° C.
16. The method of claim 1 , wherein the mixing is carried out at a temperature less than the boiling point of the organic extractive solvent.
17. The method of claim 1 , wherein separation of the mixture results in an emulsion phase, crud, or both in addition to the aqueous phase and the solvent phase and the emulsion phase, the crud, or both are further treated by:
adding a low-carbon-number alcohol to the emulsion phase, the crud, or both;
mixing the alcohol with the emulsion phase, the crud, or both to form a mixture;
separating the mixture into an organic liquid fraction, an aqueous slurry fraction, and an aqueous-organic-particle slurry fraction;
optionally, separating the aqueous-organic-particle slurry fraction into a liquid fraction and filter cakes by filtration or centrifugation; and
optionally, adding the aqueous phase to the aqueous phase that resulted from the separation of the organic extractive solvent/aqueous acid-leached ore slurry mixture and adding the solvent phase to the solvent phase that resulted from the separation of the organic extractive solvent/aqueous acid-leached ore slurry mixture.
18. A method of treating emulsion, crud, or a combination thereof formed during extraction of rare earth metals from ore or from a clear solution containing rare earth metals to recover rare earth metals contained in the emulsion, crud, or a combination thereof:
adding a low-carbon-number alcohol to the emulsion, the crud, or the combination thereof;
mixing the alcohol with the emulsion, the crud, or the combination thereof to form a mixture; and
separating the mixture into an organic liquid fraction, an aqueous slurry fraction, and an aqueous-organic-particle slurry fraction.
19. The method of claim 18 , further comprising separating the aqueous-organic-particle slurry fraction into a liquid fraction and filter cake by filtration or centrifuge.
20. The method of claim 18 , wherein the low-carbon-number alcohol comprises methanol, ethanol, n-propanol and isopropyl alcohol, n-butanol and its isomers, n-pentanol and its isomers, n-hexanol and its isomers, heptanol and its isomers, octanol and its isomers, nonanol and its isomers, or mixtures thereof.