Processes for recovering lithium values from lithium-containing brines

Patent metadata

Field	Value
Publication number	US-10648061-B2
Application number	US-201515754113-A
Country	US
Kind code	B2
Filing date	Oct 16, 2015
Priority date	Aug 28, 2015
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

Producing high purity lithium solution from a lithium source containing dissolved Na+, Ca2+, and Mg2+, by: passing the source into and out of a bed of sorbent composed of hydrated alumina intercalated with LiX, preferably LiCl, to extract lithium from the lithium source into the sorbent; washing the bed of sorbent with dilute aqueous LiCl to remove lithium from the sorbent to obtain a lithium eluent of increased Li+ concentration; subjecting this eluent to nanofiltration to produce a lithium permeate from which Ca2+, Mg2+, and other nanofilterable components are concurrently removed, yielding a permeate solution with 25% or less, and a retentate solution with 75% or more Ca2+ and Mg2+, as compared to the eluent from washing; and subjecting the permeate solution to a particular forward osmosis yielding a solution having 13,000-25,000 ppm dissolved lithium. Specified optional steps and new features can be used to increase lithium concentrations and purity.

First claim

The invention claimed is:

1. A process for producing an aqueous lithium-containing solution from a source of dissolved lithium that also contains at least Na + , Ca 2+ , and Mg 2+ in solution, which process comprises:
(A) passing said source of dissolved lithium into and out of a bed of sorbent comprised of hydrated alumina intercalated with LiX, where X is an anion of a lithium salt, to thereby extract at least a portion of lithium from the source of dissolved lithium into the sorbent;
(B) washing the bed of sorbent with a dilute solution of lithium chloride to obtain a lithium eluent solution;
(C) subjecting the lithium eluent solution to nanofiltration to produce a lithium-containing permeate solution and a retentate solution comprising a total amount of Ca 2+ and Mg 2+ of at least 75% as compared to the total amount Ca 2+ and Mg 2+ in said source of dissolved lithium and wherein the permeate solution comprises a total content of dissolved Ca 2+ and Mg 2+ that is 25% or less as compared to said lithium eluent solution; and
(D) subjecting said permeate solution to forward osmosis through a plurality of successive or parallel semi-permeable forward osmosis membranes in units that further reduce the water content of said permeate solution and thereby further increase the lithium concentration of the permeate solution so that it is in the range of about 13,000 to about 25,000 ppm of dissolved lithium.

2. A process as in claim 1 where a residual portion of the source of dissolved lithium remains within said bed after completion of step (A) and this residual portion within said bed is displaced from said bed by passing a concentrated solution of dissolved sodium halide into said bed.

3. A process as in claim 1 further comprising subjecting, after conducting the nanofiltration of step (C), said permeate solution to pressurized reverse osmosis through a plurality of successive or parallel semi-permeable reverse osmosis membranes.

4. A process as in claim 1 further comprising, after conducting the forward osmosis of step (D), precipitating solids from residual metal content comprising at least divalent metal components and/or metalloid content remaining in said permeate solution by treatment thereof with at least one base selected from sodium hydroxide, potassium hydroxide, sodium carbonate, and/or potassium carbonate; and separating the solids to obtain a purified lithium-containing solution.

5. A process as in claim 4 which further comprises contacting said purified lithium-containing solution with at least one ion exchange resin to thereby reduce the residual metal content and/or metalloid content of said purified lithium-containing solution.

6. A process as in claim 1 , wherein said sorbent is of the formula LiX.2Al(OH) 3 where X is an anion of a lithium salt, and which has a lithium to aluminum molar ratio of up to about 0.50.

7. A process as in claim 6 wherein said sorbent is prepared by contacting gibbsite with an aqueous solution of lithium chloride and sodium hydroxide to form a precursor sorbent of the formula (LiOH) a (LiCl) 1-a .2Al(OH) 3 , where a=0 to 1, followed by reaction with an aqueous solution of hydrochloric acid to convert LiOH in the precursor sorbent to LiCl.

8. A process as in claim 7 wherein said gibbsite has been morphologically altered by compression and has an average particle size of at least 300 microns and a surface area of at least 3 m 2 /g.

9. A process as in claim 1 wherein said source of dissolved lithium is from a natural or industrial brine that has a lithium concentration of at least about 100 ppm.

10. A process as in claim 1 wherein in (A) at least 50% or more of lithium is extracted from the source of dissolved lithium into the sorbent.

11. A process as in claim 1 wherein in (B) said dilute solution of lithium chloride to unload lithium from the sorbent has a lithium chloride concentration in the range of about 300 ppm to about 3000 ppm.

12. A process as in claim 1 wherein in step (B) said lithium eluent solution has a Li + concentration in the range of about 1500 ppm to about 5000 ppm.

13. A process as in claim 1 wherein in (C) said lithium eluent solution comprises at least Ca 2+ and/or Mg 2+ impurities in solution and in a weight ratio of dissolved Li + :Ca 2+ and/or Li + :Mg 2+ in the range of about 4:1 to 50:1 wt/wt.

14. A process as in claim 1 wherein
said sorbent is of the formula LiX.2Al(OH) 3 where X is an anion of a lithium salt, and which has a lithium to aluminum molar ratio of up to about 0.50;
said sorbent has been prepared by contacting gibbsite with an aqueous solution of lithium chloride and sodium hydroxide to form a precursor sorbent of the formula (LiOH) a (LiCl) 1-a .2Al(OH) 3 , where a=0 to 1, followed by reaction with an aqueous solution of hydrochloric acid to convert LiOH in the precursor sorbent to LiCl;
said gibbsite used in forming said sorbent in its preparation was morphologically altered by compression to have an average particle size of at least 300 microns and a surface area of at least 3 m 2 /g;
the source of dissolved lithium is from a natural or industrial brine that has a lithium concentration of at least about 100 ppm;
the lithium eluent solution of increased Li + concentration has a Li + concentration in the range of about 1500 ppm to about 5000 ppm; and
said lithium eluent solution comprises at least Ca 2+ and/or Mg 2+ impurities in solution and in a weight ratio of dissolved Li + :Ca 2+ and/or Li + :Mg 2+ in the range of about 4:1 to 50:1 wt/wt.

15. A process as in claim 1 wherein said bed of sorbent in step (A) is a bed of granular sorbent.

16. A process as in claim 1 where X is chloride, wherein said source of dissolved lithium is from a natural or industrial brine that has a lithium concentration of greater than 180 ppm, and/or wherein in (A) about 80% or more of lithium is extracted from the source of dissolved lithium into the sorbent.

Assignees

• Albemarle Corp

Inventors

• Cheng Chi Hung
• Switzer Jackson R
• Nieman Jan

Classifications

• C01D15/04

  Halides · CPC title

• B01J20/08

  comprising aluminium oxide or hydroxide; comprising bauxite · CPC title

• B01J2220/56

  Use in the form of a bed · CPC title

• B01J20/3028

  Granulating, agglomerating or aggregating · CPC title

• B01J20/28004

  Sorbent size or size distribution, e.g. particle size · CPC title