Lithium extraction method

Patent metadata

Field	Value
Publication number	US-2020071794-A1
Application number	US-201816490243-A
Country	US
Kind code	A1
Filing date	Feb 28, 2018
Priority date	Mar 1, 2017
Publication date	Mar 5, 2020
Grant date	—

Abstract

According to the present invention there is provided a method for the extraction of lithium from one or more lithium-containing ores such as spodumene, the inventive method comprising the steps of: milling said ore/s to a predetermined average particle size; optionally calcining the milled ore; further optionally performing a secondary milling step; providing an aqueous suspension of the one or more lithium-containing ores at a predetermined solids concentration; subjecting the one or more lithium-containing ores to an aqueous extraction medium defined by a predetermined partial pressure of CO2, a predetermined extraction temperature, over a predetermined time; and obtaining technical grade lithium carbonate/lithium bicarbonate therefrom. Optional concentration and/or precipitation/purification steps may follow.

First claim

The claims defining the invention are as follows:

1 . Use of carbonic acid, or aqueous carbon dioxide in the extraction of lithium from one or more lithium-containing ores.

2 . Use according to claim 1 , wherein the one or more lithium-containing ores comprise β-spodumene; or wherein the one or more lithium-containing ores consist essentially of β-spodumene.

3 . Use according to claim 1 or claim 2 , wherein the one or more lithium-containing ores are selected from the group consisting of spodumene, eucryptite, petalite, amblygonite, lepidolite, zinnwaldite, lithiophilite, and tryphilite, hectorite and jadarite,

4 . A method for the extraction of lithium from one or more lithium-containing ores, said method comprising the steps of:
a) milling said one or more lithium-containing ores to a predetermined average particle size to provide a milled crude ore; b) optionally calcining said milled crude ore at a predetermined calcining temperature; c) if step b) is performed, optionally performing a secondary milling step upon the calcined milled crude ore thus obtained; d) providing an aqueous suspension of the milled crude ore (calcined or non-calcined), at a predetermined solids concentration; e) subjecting said milled crude ore to an extraction medium defined by a predetermined partial pressure of CO 2 , a predetermined extraction temperature, over a predetermined time; and f) obtaining technical grade lithium carbonate/lithium bicarbonate in solution therefrom.

5 . A method according to claim 4 , wherein the one or more lithium-containing ores comprise β-spodumene, or wherein the one or more lithium-containing ores consist essentially of β-spodumene.

6 . A method according to claim 4 , wherein the predetermined calcining temperature is greater than about 900° C., thereby to convert α-spodumene to β-spodumene.

7 . A method according to any one of claims 4 to 6 , wherein said predetermined partial pressure of CO 2 is between about 0.1 and about 300 bar.

8 . A method according to any one of claims 4 to 7 , wherein said predetermined extraction temperature is between about 20° C. and about 350° C.

9 . A method according to any one of claims 4 to 8 , wherein said predetermined solids concentration is between about 0.1 and about 60% w/w.

10 . A method according to any one of claims 4 to 9 , wherein said predetermined average particle size is between about 0.1 μm and about 1000 μm.

11 . A method according to any one of claims 4 to 10 , wherein said predetermined time is between about 1 and about 1000 minutes.

12 . A method according to any one of claims 4 to 11 , giving rise to a yield (on an extracted lithium to crude lithium basis) of between about 1% and about 99%.

13 . A method according to any one of claims 4 to 12 , wherein one or more impurities extracted from said one or more lithium-containing ores comprise Na, K, Mg, Ca, Mn, Fe, Al, and Si.

14 . A method according to claim 13 , wherein each of said one or more impurities is present at a concentration between about 0.5% and about 40% of the lithium concentration on a molar basis.

15 . A method according to any one of claims 4 to 14 , further comprising a concentration step g), wherein the technical grade lithium carbonate obtained in solution from step f) is concentrated.

16 . A method according to claim 15 , wherein said concentration step comprises standard concentration techniques of the art, including but not limited to: the addition of a concentrator, evaporation, reverse osmosis, electrodialysis, liquid-liquid extraction, selective adsorption and solid state extraction and/or membrane separation.

17 . A method according to claim 15 , wherein following said concentration step g), the lithium carbonate precipitates out of solution.

18 . A method according to claim 17 , further comprising a filtration step h), thereby to separate the precipitated lithium carbonate from the mother liquor.

19 . A method according to any one of claims 4 to 18 , adaptable and/or scalable to a continuous flow or batch-type scenario.

20 . A method according to any one of claims 4 to 19 , wherein the aqueous medium comprises water, one of more mineral acids, one or more organic acids, one or more alkaline salts, one or more ionic liquids, and combinations thereof.

21 . A method according to claim 20 , wherein the one of more mineral acids are optionally supplemented with a predetermined partial pressure of CO 2 between about 0.1 and about 300 bar.

22 . Lithium, when extracted from one or more lithium-containing ores by a method as defined according to any one of claims 4 to 21 .

23 . Lithium according to claim 22 , as lithium carbonate/bicarbonate, at a purity of at least about 85% on a molar basis.

24 . An apparatus for facilitating the extraction of lithium from one or more lithium-containing ores, said apparatus comprising:
means for providing an aqueous suspension of said one or more lithium-containing ores, at a predetermined solids concentration; means for subjecting said one or more lithium-containing ores to an extraction medium defined by a predetermined partial pressure of CO 2 , a predetermined extraction temperature, over a predetermined time; and means for obtaining technical grade lithium carbonate/lithium bicarbonate therefrom.

25 . An apparatus according to claim 24 , further comprising means for effecting an initial milling step, whereby the one or more lithium-containing ores are milled to a predetermined average particle size to provide a milled crude ore prior to being provided as the aqueous suspension.

26 . An apparatus according to claim 25 , further comprising means for effecting a calcining step following said milling step.

Assignees

• Univ Sydney

Inventors

• Haynes Brian
• Mann Jason

Classifications

• C22B26/12 Primary

  Obtaining lithium · CPC title

• C22B3/06 Primary

  in inorganic acid solutions {, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions} · CPC title

• C01D15/08

  Carbonates; Bicarbonates · CPC title

• C22B1/24

  Binding; Briquetting {; Granulating} · CPC title

• Y02P10/20

  Recycling · CPC title