Methods of recovering rare earth metals

Patent metadata

Field	Value
Publication number	US-2023257278-A1
Application number	US-202318110333-A
Country	US
Kind code	A1
Filing date	Feb 15, 2023
Priority date	Feb 16, 2022
Publication date	Aug 17, 2023
Grant date	—

Abstract

A method of recovering a rare earth metal can include incubating a bacterial consortium in the presence of a rare earth metal source comprising a rare earth metal and iron. The bacterial consortium can include an acid secreting bacterium, a heavy metal resistant bacterium, an iron-sequestering molecule secreting bacterium, and a rare earth metal sequestering bacterium. The method can further include: producing an acid using the acid secreting bacterium; leaching iron and the rare earth metal from the rare earth metal source using the acid; protecting the bacterial consortium from metal using the heavy metal resistant bacterium; sequestering iron using the iron-sequestering molecule secreting bacterium; and sequestering the rare earth metal using the rare earth metal sequestering bacterium

First claim

What is claimed is:

1 . A method of recovering a rare earth metal comprising:
incubating a bacterial consortium in the presence of a rare earth metal source comprising a rare earth metal and iron, wherein the bacterial consortium comprises an acid secreting bacterium, a heavy metal resistant bacterium, an iron-sequestering molecule secreting bacterium, and a rare earth metal sequestering bacterium; producing an acid using the acid secreting bacterium; leaching iron and the rare earth metal from the rare earth metal source using the acid; protecting the bacterial consortium from metal using the heavy metal resistant bacterium; sequestering iron using the iron-sequestering molecule secreting bacterium; and sequestering the rare earth metal using the rare earth metal sequestering bacterium.

2 . The method of claim 1 , wherein the sequestered rare earth metal is in an oxide form or a sulfate form.

3 . The method of claim 1 , wherein the sequestered rare earth metal is neodymium.

4 . The method of claim 1 , wherein the bacterial consortium is incubated in the presence of the rare earth metal source at a temperature from about 20° C. to about 90° C.

5 . The method of claim 1 , wherein the bacterial consortium and the rare earth metal source are in an aqueous medium having a pH from 4 to 6.

6 . The method of claim 1 , wherein the bacterial consortium is incubated with the rare earth metal source in a growth medium comprising:
water, magnesium sulfate, manganese chloride, cobalt chloride, calcium chloride, ammonium sulfate, soluble starch, and amino acids.

7 . The method of claim 6 , wherein the bacterial consortium is incubated with the rare earth metal source in the growth medium for an incubation time of about 1 week to about 6 weeks.

8 . The method of claim 7 , wherein the bacterial consortium is incubated with the rare earth metal source in the growth medium for the incubation time without any input.

9 . The method of claim 7 , wherein the bacterial consortium is incubated with the rare earth metal source in the growth medium for the incubation time while feeding the bacterial consortium with new growth medium at a rate from about 0.5 mL per 100 mL of the composition per hour to about 2 mL per 100 mL of the composition per hour.

10 . The method of claim 1 , wherein the acid secreting bacterium is an organic acid secreting bacterium.

11 . The method of claim 10 , wherein the organic acid secreting bacterium is a citric acid secreting bacterium.

12 . The method of claim 11 , wherein the citric acid secreting bacterium is Bacillus sp.

13 . The method of claim 10 , wherein the organic acid secreting bacterium is a butyric acid secreting bacterium.

14 . The method claim 13 , wherein the butyric acid secreting bacterium is Butyrivibrio hungatei.

15 . The method of claim 10 , wherein the organic acid secreting bacteria is an amino acid fermenting bacterium.

16 . The method of claim 15 , wherein the amino acid fermenting bacterium is Clostridia venationis.

17 . The method of claim 1 , wherein the heavy metal resistant bacterium resists heavy metal by active transport of metal ions, extracellular sequestration, intracellular sequestration, reduction of metal ions to insoluble metal, an extracellular barrier, or a combination thereof.

18 . The method of claim 1 , wherein the heavy metal resistant bacterium is from the order Burkholderiales or genus Cupriavidus.

19 . The method of claim 1 , wherein the bacterial consortium and the rare earth metal source are in an aqueous medium having a heavy metal concentration from 10 grams per liter to 50 grams per liter.

20 . The method of claim 1 , wherein the heavy metal resistant bacterium contains a plasmid with at least 99% sequence identity to the pMOL30 plasmid of Burkholderiales.

21 . The method of claim 1 , wherein the iron-sequestering molecule secreting bacterium secretes an iron-sequestering protein or an iron-sequestering siderophore.

22 . The method of claim 21 , wherein the iron-sequestering molecule secreting bacterium is capable of or otherwise operable to secrete at least 10 grams of iron-sequestering protein per 10 12 bacterial cells.

23 . The method of claim 1 , wherein the iron-sequestering molecule secreting bacterium is Acinetobacter baumanni.

24 . The method of claim 1 , wherein the rare earth metal sequestering bacterium sequesters rare earth metals by intracellular sequestration, extracellular sequestration, conversion to an insoluble metal, sequestration into a glycocalyx, sequestration by a specific binding protein, or a combination thereof.

25 . The method of claim 1 , wherein the rare earth metal sequestering bacterium is capable of or otherwise operable to sequester at least 10 grams of rare earth metal per 10 12 bacterial cells.

26 . The method of claim 1 , wherein the rare earth metal sequestering bacterium is a xanthan gum secreting bacterium.

27 . The method of claim 26 , wherein the xanthan gum secreting bacterium is Xanthomonas vesicatoria.

28 . The method of claim 26 , further comprising skimming off xanthan gum having the rare earth metal bound thereto and filtering out the xanthan gum and rare earth metal.

29 . The method of claim 1 , wherein the rare earth metal sequestering bacterium is Peptostreptococcus anaerobius or a Lactobacillus having a rare earth metal sequestering S-layer.

30 . The method of claim 1 , wherein the bacterial consortium further comprises Collinsella aerofaciens.

31 . The method of claim 30 , wherein the bacterial consortium further comprises axonopodis, brevis, anaerobius, frisia, coli, guillouiae, parainfluenzae, oryziterrae, subtilis , or a combination thereof

32 . The method of claim 1 , wherein the incubating is performed in an anaerobic environment.

33 . The method of claim 1 , wherein a ratio of the number of acid secreting bacteria to heavy metal resistant bacteria to iron-sequestering molecule secreting bacteria to rare earth metal sequestering bacteria is 1-100 acid secreting bacteria to 1-100 heavy metal resistant bacteria to 1-100 iron-sequestering molecule secreting bacteria to 1-100 rare earth metal sequestering bacteria.

34 . The method of claim 1 , further comprising recovering the liberated rare earth metal and converting the liberated rare earth metal to a nitrate.

35 . The method of claim 34 , further comprising purifying the nitrate and converting the nitrate into an oxide of the rare earth metal.

36 . A method of harvesting a rare earth metal from a rare earth metal source (REMS) comprising:
leaching metals from the REMS using an acid produced by an acid secreting bacterium to provide a leachate; protecting bacterium in proximity to the leachate from heavy metal toxicity with a heavy metal resistant bacterium; sequestering any iron metal in the leachate with an iron-sequestering molecule secreting bacterium; and sequestering the rare earth metal from the leachate with a rare earth metal sequestering bacterium.

Assignees

• Raytheon Bbn Technologies Corp
• Saro Res Llc

Inventors

• Rogers Miles
• Ashkar Samy

Classifications

• C22B3/18

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

• C01F17/10 Primary

  Preparation or treatment, e.g. separation or purification · CPC title

• C01F17/224

  Oxides or hydroxides of lanthanides · CPC title

• C01F17/282

  Sulfates · CPC title

• C01F17/276

  Nitrates · CPC title