Systems and methods for separating and recovering rare earths

Patent metadata

Field	Value
Publication number	US-9850555-B2
Application number	US-201414772861-A
Country	US
Kind code	B2
Filing date	Mar 10, 2014
Priority date	Mar 15, 2013
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

The present application is generally directed to separation and recovery of rare earths using biomass, liposomes, and/or other materials. In some embodiments, a composition comprising rare earths is exposed to biomass, where some of the rare earths are transferred to the biomass, e.g., via absorption. The composition may then be separated from the biomass. A solution may be exposed to the biomass thereby enriching the solution in one or more rare earths, relative to other rare earths in the biomass. The solution and the biomass may then be separated, and the rare earths recovered from the solution. In some cases, this process may be repeated with different solutions, which may result in different solutions enriched in various rare earths. Similar processes may be used to separate the rare earths from thorium and uranium. Liposomes may be used instead of and/or in addition to biomass.

First claim

What is claimed is:

1. A method, comprising:
providing biomass comprising an initial molar ratio of a first rare earth to a second rare earth;
exposing the biomass to a first solution to cause the first solution to have a first molar ratio of first rare earth to second rare earth;
removing at least a portion of the first solution; and
exposing the biomass to a second solution different from the first solution to cause the second solution to have a second molar ratio of first rare earth to second rare earth, wherein the first solution has a first pH that is less than or equal to about 2.5 and the second solution has a second pH different from the first pH.

2. The method of claim 1 , wherein the concentration of ions in the second solution is greater than the concentration of ions in the first solution.

3. The method of claim 1 , wherein the first molar ratio and the second molar ratio are each greater than the initial molar ratio.

4. The method of claim 1 , wherein the first molar ratio is greater than the second molar ratio.

5. The method of claim 1 , wherein the second molar ratio is less than the initial molar ratio.

6. The method of claim 1 , wherein the first and second rare earths are each independently selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

7. The method of claim 1 , wherein the biomass comprises bacteria.

8. The method of claim 1 , wherein the biomass comprises an exopolysaccharide.

9. The method of claim 1 , wherein the biomass comprises lignin.

10. The method of claim 1 , wherein the first and second rare earths associate with the surface of the biomass.

11. The method of claim 1 , wherein the difference in atomic number between the first rare earth and the second rare earth is less than or equal to 3.

12. The method of claim 1 , further comprising exposing the biomass to an acid prior to exposing the biomass to the first solution to produce the biomass comprising the initial molar ratio of the first rare earth to the second rare earth.

13. The method of claim 12 , wherein the acid has a pH different from the second pH of the second solution.

14. The method of claim 1 , further comprising passing the at least a portion of the first solution comprising the first molar ratio of first rare earth and second rare earth through a plurality of stages, wherein in at least some of the stages, the rare earths are exposed to one or more biomasses that have a greater affinity for the second rare earth than the first rare earth; and recovering, from the plurality of stages, an exiting solution having an increased molar ratio of first rare earth to the second rare earth relative to the first solution.

15. The method of claim 1 , further comprising exposing at least a portion of the first solution to a second biomass.

Assignees

• Harvard College

Inventors

• Bonificio William Daley
• Clarke David

Classifications

• Y02P10/238

  Cross-Sectional Technologies · mapped topic

• B09C1/10

  microbiologically, {biologically} or by using enzymes · CPC title

• C22B3/18

  with the aid of microorganisms or enzymes, e.g. bacteria or algae · CPC title

• Y02P10/234

  Cross-Sectional Technologies · mapped topic

• C22B59/00 Primary

  Obtaining rare earth metals · CPC title