Systems and methods for separating and recovering rare earths

Patent metadata

Field	Value
Publication number	US-2016017459-A1
Application number	US-201414772861-A
Country	US
Kind code	A1
Filing date	Mar 10, 2014
Priority date	Mar 15, 2013
Publication date	Jan 21, 2016
Grant date	—

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, such that some of the rare earths are released from the biomass into the solution, 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, e.g., having differences in pH or ionic concentration, which may result in different solutions enriched in various rare earths. In addition, in some embodiments, similar processes may be used to separate the rare earths from thorium and uranium. Also, in some embodiments, 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; 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.

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 any one of claim 1 or 2 , wherein the first molar ratio and the second molar ratio are each greater than the initial molar ratio.

4 . The method of any one of claims 1 - 3 , wherein the first molar ratio is greater than the second molar ratio.

5 . The method of any one of claims 1 - 4 , wherein the second molar ratio is less than the initial molar ratio.

6 . The method of any one of claims 1 - 5 , 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 any one of claims 1 - 6 , wherein the first and second rare earths are each independently selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

8 . The method of any one of claims 1 - 7 , wherein the first and second rare earths are each independently selected from the group consisting of La, Ce, Pr, and Nd.

9 . The method of any one of claims 1 - 8 , wherein the first and second rare earths are each independently selected from the group consisting of Ho, Er, Tm, Yb, and Lu.

10 . The method of any one of claims 1 - 9 , wherein the biomass comprises bacteria.

11 . The method of any one of claims 1 - 10 , wherein the biomass comprises living cells.

12 . The method of claim 11 , wherein the living cells include one or more of bacteria, eukaryotes, archaea, or fungi.

13 . The method of any one of claims 1 - 10 , wherein the biomass does not comprise living cells.

14 . The method of any one of claims 1 - 13 , wherein the biomass comprises dead cells.

15 . The method of any one of claims 1 - 14 , wherein the biomass comprises an exopolysaccharide.

16 . The method of any one of claims 1 - 15 , wherein the biomass comprises lignin.

17 . The method of any one of claims 1 - 16 , wherein the first and second rare earths associate with the surface of the biomass.

18 . The method of any one of claims 1 - 17 , wherein the difference in atomic number between the first rare earth and the second rare earth is less than or equal to 3.

19 . The method of any one of claims 1 - 18 , wherein the difference in atomic number between the first rare earth and the second rare earth is less than or equal to 2.

20 . The method of any one of claims 1 - 19 , wherein the difference in atomic number between the first rare earth and the second rare earth is 1.

21 . The method of any one of claims 1 - 20 , wherein at least one of the first and second rare earths is present as an oxide.

22 . The method of any one of claims 1 - 21 , wherein at least one of the first and second rare earths is present as ions.

23 . The method of any one of claims 1 - 22 , wherein at least one of the first and second rare earths is contained in a mineral.

24 . The method of claim 23 , wherein the mineral comprises bastnaesite, monazite, or xenotime.

25 . The method of any one of claims 1 - 24 , further comprising exposing at least one of the first and second rare earths to a chelator.

26 . The method of claim 25 , wherein the chelator comprises one or more of dipicolinic acid, citric acid, diethylene triamine pentaacetic acid, 1,2-cyclohexane diamine tetra acetic acid, or ethylenediaminetetraacetic acid.

27 . 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 comprising non-hydrogen ions 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; exposing the biomass to a second solution comprising non-hydrogen ions different from the first solution to cause the second solution to have a second molar ratio of first rare earth to second rare earth.

28 . The method of claim 27 , wherein the first molar ratio and the second molar ratio are each greater than the initial molar ratio.

29 . The method of any one of claim 27 or 28 , wherein the second molar ratio is less than the initial molar ratio.

30 . The method of any one of claims 27 - 29 , wherein the difference in atomic number between the first rare earth and the second rare earth is less than or equal to 3.

31 . The method of any one of claims 27 - 30 , further comprising exposing at least one of the first and second rare earths to a chelator.

32 . A method, comprising:
passing an initial solution comprising a molar ratio of first and second rare earths through a plurality of stages in a flow reactor, wherein in at least some of the stages, the rare earths are exposed to biomass such that the second rare earths have a greater affinity for biomass than the first rare earths; and recovering, from the plurality of stages, a exiting solution having an increased molar ratio of first rare earth relative to the second rare earth, relative to the initial solution.

33 . The method of claim 32 , wherein the biomass comprises bacteria.

34 . The method of any one of claim 32 or 33 , wherein the difference in atomic number between the first rare earth and the second rare earth is less than or equal to 3.

35 . The method of any one of claims 32 - 34 , wherein the first and second rare earths are rare earth ions.

36 . The method of any one of claims 32 - 35 , comprising passing an ionic solution through the plurality of stages in the flow reactor.

37 . The method of claim 36 , wherein the ionic solution has an ionic strength of at least about 10 −3 M.

38 . The method of any one of claims 32 - 37 , further comprising recovering, from the plurality of stages, a second exiting solution having an increased molar ratio of second rare earth relative to the first rare earth, relative to the initial solution.

39 . The method of any one of claims 32 - 38 , further comprising recycling at least a portion of the exiting solution into the flow reactor.

40 . A method comprising:
culturing biomass in a solution comprising an initial molar ratio of a first rare earth to a second rare earth to cause the solution to have an increased molar ratio of the first rare earth to the second rare earth, relative to the initial molar ratio; and removing at least a portion of the solution from the biomass.

41 . The method of claim 40 wherein the biomass comprises bacteria.

42 . The method of any one of claim 40 or 41 , wherein the

Assignees

• Harvard College

Inventors

• Bonificio William Daley
• Clarke David

Classifications

• C22B59/00 Primary

  Obtaining rare earth metals · CPC title

• C22B7/006

  Wet processes · CPC title

• C22B3/18

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

• Y02P10/20

  Recycling · CPC title

• B09C1/10

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