LITHIUM EXTRACTION FROM ORE BY ELECTROLYSIS

Abstract

Provided herein are a two-stage method and a system for extracting lithium from lithium ore. The method comprises extracting lithium from lithium ore and transferring the lithium to a molten metal, thereby forming a lithium-rich molten metal alloy, and transferring the lithium from the lithium-rich molten metal alloy to a conductive substrate.

Claims

1. A method comprising: (a) contacting a source of lithium with a molten metal; (b) extracting lithium from the source of lithium and transferring the lithium to the molten metal, thereby forming a lithium-rich molten metal alloy; and (c) transferring the lithium from the lithium-rich molten metal alloy to a conductive substrate.

2. The method of claim 1, wherein the source of lithium comprises a borate melt.

3. The method of claim 2, further comprising, before (a), dissolving a material comprising lithium ions in the borate melt.

4. The method of claim 3, wherein the material comprising lithium ions comprises a lithium ore.

5. The method of claim 4, wherein the lithium ore comprises spodumene.

6. The method of claim 2, wherein the borate melt comprises a fluoride salt.

7. The method of claim 6, wherein the fluoride salt is selected from the group consisting of NaF, KF, CaF.sub.2, and combinations thereof.

8. The method of claim 2, wherein the molten metal has a higher density than the borate melt.

9. The method of claim 1, wherein (b) comprises applying a voltage across an anode and the molten metal.

10. The method of claim 1, further comprising, before (c), contacting the lithium-rich molten metal alloy with a molten salt electrolyte.

11. The method of claim 10, wherein (c) comprises applying a voltage across a cathode and the lithium-rich molten metal alloy, causing lithium ions to be released from the lithium-rich molten metal alloy and reduced to lithium metal at the cathode.

12. The method of claim 2, wherein the borate melt is maintained at a temperature between 600? C. and 1000? C.

13. The method of claim 11, wherein (c) is performed at a temperature between 300? C. and 800? C.

14. The method of claim 11, wherein the cathode comprises an inert material.

15. The method of claim 14, wherein the cathode comprises nickel, copper, titanium, and carbon.

16. The method of claim 10, wherein the molten salt electrolyte comprises a salt selected from the group consisting of lithium halides, sodium halides, potassium halides, and combinations thereof.

17. The method of claim 16, wherein the molten salt electrolyte comprises a salt selected from the group consisting of LiCl, KCl, RbCl, CsCl, SrCl.sub.2, BaCl.sub.2, and combinations thereof.

18. The method of claim 16, wherein the molten salt electrolyte comprises fluoride salts.

19. The method of claim 18, wherein the fluoride salts are selected from the group consisting of LiF, CaF.sub.2, and combinations thereof.

20. The method of claim 1, wherein (a) and (b) are carried out in a first cell, and (c) is carried out in a second cell that is different from the first cell.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The foregoing features of embodiments will be more readily understood by reference to the following detailed description, taken with reference to the accompanying drawings, in which:

[0034] FIG. 1 provides the steps associated with an embodiment of the disclosed method.

[0035] FIG. 2 illustrates a first stage in which lithium ions dissolved in a borate melt are electrolytically reduced at a layer of molten metal functioning as a cathode to form a lithium alloy with the molten metal, in accordance with some embodiments.

[0036] FIG. 3 illustrates a second stage in which the lithium alloy with the molten metal serves as an anode in an electrolytic cell, releasing lithium ions into a molten salt electrolyte. At the cathode of the cell, the lithium ions are reduced to lithium metal, thereby providing a layer of high purity lithium that floats to the top of the molten salt electrolyte.

DETAILED DESCRIPTION

[0037] Unless defined otherwise, all terms of art, notations and other technical and scientific terms or terminology used herein are intended to have the same meaning as is commonly understood by one of ordinary skill in the art to which the claimed subject matter pertains. In some cases, terms with commonly understood meanings are defined herein for clarity and/or for ready reference, and the inclusion of such definitions herein should not necessarily be construed to represent a substantial difference over what is generally understood in the art.

[0038] Throughout this application, various embodiments may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0039] As used in the specification and claims, the singular forms a, an and the include plural references unless the context clearly dictates otherwise. For example, the term a sample includes a plurality of samples, including mixtures thereof.

[0040] Whenever the term at least, greater than, or greater than or equal to precedes the first numerical value in a series of two or more numerical values, the term at least, greater than or greater than or equal to applies to each of the numerical values in that series of numerical values. For example, greater than or equal to 1, 2, or 3 is equivalent to greater than or equal to 1, greater than or equal to 2, or greater than or equal to 3.

[0041] The expressions at least about A, B, and C and at least about A, B, or C may be construed to mean at least about A, at least about B, or at least about C. The expressions at most about A, B, and C and at most about A, B, or C may be construed to mean at most about A, at most about B, or at most about C.

[0042] The expression between about A and B, C and D, and E and F may be construed to mean between about A and about B, between about C and about D, and between about E and about F. The expression between about A and B, C and D, or E and F may be construed to mean between about A and about B, between about C and about D, or between about E and about F.

[0043] As used herein, the term about a number refers to that number plus or minus 10% of that number. The term about a range refers to that range minus 10% of its lowest value and plus 10% of its greatest value.

[0044] The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0045] A cathode is an electrode where reduction occurs.

[0046] An anode is an electrode where oxidation occurs.

[0047] The term spodumene refers to a lithium aluminum silicate mineral with the chemical formula LiAl(SiO.sub.3).sub.2 and is the dominant lithium ore and one of the primary sources of lithium. Spodumene is typically found in granitic pegmatites, a type of rock that forms from slowly cooling magma deep within the Earth's crust. There are two main crystalline forms of spodumene: alpha-spodumene and beta-spodumene. Alpha-spodumene is the more common, naturally occurring form, while beta-spodumene forms when alpha-spodumene is heated to high temperatures (above 900? C.). Beta-spodumene is more reactive and easier to process for lithium extraction than the alpha form.

[0048] A fluoroborate melt is a molten mixture of borate salts and fluoride salts. It refers to a mixture of fluoroborate compounds in their liquid or molten state. Fluoroborates are compounds that contain boron, fluorine, and other elements. They are a subclass of the larger borate family but have a distinct chemical composition featuring the BF4.sup.? anionic group.

[0049] Borate salts are salts with oxyborate anions.

[0050] The term borate melt refers to a mixture of borate compounds in their liquid/molten state. Borates are compounds that contain boron and oxygen, typically in the form of the BO.sub.3 or BO.sub.4 anionic groups. Examples of common borates include borax (Na.sub.2B.sub.4O.sub.7.Math.10H.sub.2O), boric acid (H.sub.3BO.sub.3), and lithium borate (Li.sub.2B.sub.4O.sub.7).

[0051] Oxyborate anions are anions with chemical formula of B.sub.xO.sub.y.sup.n-, where x, y, and n are positive integers not equal to zero. Common oxyborate anions include BO.sub.3.sup.3-, B.sub.4O.sub.7.sup.2-, and B.sub.2O.sub.4.sup.2-.

[0052] The term molten salt electrolyte refers to a type of electrolyte that consist of salt compounds in a liquid or molten state. They are essential components in electrochemical processes, including batteries, fuel cells, and various other applications. Molten salt electrolytes are formed by heating solid salts to high temperatures until they melt, turning into a liquid form. These high temperatures allow ions in the salt to move more freely, facilitating ionic conductivity. According to some embodiments of this disclosure, the molten salt electrolyte includes at least one ionic species having a higher reduction potential than Li.sup.+. According to some embodiments, the molten salt electrolyte comprises one or more salts selected from the group consisting of aluminum salts, titanium salts, alkali metal salts, alkaline earth metal salts, ammonium salts, and combinations thereof. In some embodiments, the molten salt electrolyte comprises aluminum salts. In some embodiments, the aluminum salts comprises aluminum chloride. In some embodiments, the molten salt electrolyte comprises anions chosen from the group consisting of halides, nitrates, nitrites, sulfates, sulfites, carbonates, hydroxides and combinations thereof.

[0053] In some embodiments, the molten salts may comprise solutions of AlCF, and may include LiCl, NaCl, and KCl. Some such embodied chloroaluminate molten salt electrolytes can operate at temperatures at or near the boiling point of water.

[0054] The molten salt electrolytes disclosed herein are non-flammable. Because these inorganic molten salt electrolytes operate at temperatures well below the melting point of lithium, they are not significantly corrosive, and there is no danger from the leakage of molten lithium.

[0055] An example of the disclosed method involves two electrochemical stages, as summarized in FIG. 1, and according to the embodiments of FIG. 2 (Stage 1) and FIG. 3 (Stage 2).

Stage 1:

[0056] a. Dissolve lithium ore or other lithium ion containing material in a borate melt 10, the borate melt 10 including a fluoride salt in a first cell 20 (step 1 of FIG. 1); [0057] b. position the borate melt 10 on top of a layer of molten metal 30, the molten metal 30 being denser than the borate melt 10 (step 3 of FIG. 1); [0058] c. immerse a carbon anode 40 in the borate melt 10 (step 5 of FIG. 1); and [0059] d. apply a current 50 between the anode 40 and the layer of molten metal 30, thereby forming an alloy of lithium and other reduced metals from the lithium ore (step 7 of FIG. 1), and releasing gas 55 as CO/CO.sub.2 at the anode 40.

Stage 2:

[0060] a. Dispose the layer of molten metal 30, now comprising an alloy of molten metal and lithium from Stage 1 in the bottom of a second cell 60 and cover with a molten salt electrolyte 70 (step 9 of FIG. 1); [0061] b. immerse a cathode 80 in the molten salt electrolyte 70 (step 11 of FIG. 1), wherein the cathode is a conductive substrate; and [0062] c. apply a current 90 across the cathode 80 and the alloy of molten metal and lithium, releasing Li.sup.+ from the alloy and reducing the Li.sup.+ to form a layer of lithium metal 100 at the cathode 80 (step 13 of FIG. 1).

[0063] In some embodiments, the lithium ore or other lithium ion containing material of stage one includes, but not limited to spodumene (LiAlSi.sub.2O.sub.6), lepidolite (K(Li,Al,Rb).sub.2(Al,Si).sub.4O.sub.10(F,OH).sub.2), petalite (LiAlSi.sub.4O.sub.10), lithium brines, hectorite clay (Na.sub.0.3(Mg,Li).sub.3Si.sub.4O.sub.10(OH).sub.2), geothermal brines, or recycled lithium-ion batteries.

[0064] In some embodiments, the borate melt 10 includes borate salts chosen from the group consisting of sodium salts, potassium salts, calcium salts, magnesium salts, and combinations thereof. In some embodiments, the borate melt includes fluoride salts. In some embodiments, the fluoride salts are chosen from the group consisting of NaF, KF, CaF.sub.2, MgF.sub.2, and combinations thereof. The borate melt 10 may be capable of breaking down the lithium ore structure by dissolving metal oxides, including lithium oxide (Li.sub.2O) present in the ore. The metal fluoride components may improve the solubility of the lithium compounds in the borate melt. In some embodiments, the temperature of the borate melt 10 is between 850 and 950 degrees centigrade. In some embodiments, the temperature of the borate melt 10 is higher than about 700? C., 750? C., 800? C., 850? C., 900? C., 950? C., or 1000? C. In some embodiments, the temperature of the borate melt 10 is lower than about 700? C., 750? C., 800? C., 850? C., 900? C., 950? C., or 1000? C. In some embodiments, the temperature of the borate melt 10 is between about 700? C. and 1000? C., between about 750? C. and 950? C., between about 800? C. and 900? C., or between about 850? C. and 1000? C. In some embodiments, after the lithium ore is dissolved in the borate melt containing the metal fluoride, the melt may be cooled and solidified.

[0065] In some embodiments, the layer of molten metal 30 of stage one includes a metal selected from the group consisting of Al, Sn, Pb, Bi, Sb, Zn, and alloys of the same. In some embodiments, the layer of molten metal includes Sn. In some embodiments, the layer of molten metal includes an alloy of Pb and Sb.

[0066] In some embodiments, the anode 40 of stage one includes carbon, so that as lithium ion is reduced at the layer of molten metal 30, forming a lithium-containing alloy, carbon at the anode 40 is oxidized to CO.sub.2 or CO, which is released as a gas. In some embodiments, the anode electrode 40 comprises graphite, platinum (Pt), titanium (Ti), or a combination thereof.

[0067] In some embodiments, when a current 50 is applied across the anode 40 and the layer of molten metal 30, the molten metal may selectively extract lithium from a lithium-containing source, such as a borate melt with lithium salts. In some embodiments, lithium may be soluble in the molten metals, resulting in the formation of a lithium-rich molten metal alloy. In some embodiments, the lithium-rich molten metal alloy comprises lithium of at least about 0.1 weight % (wt %), 0.2 wt %, 0.4 wt %, 0.6 wt %, 0.8 wt %, 1 wt %, 2 wt %, 4 wt %, 6 wt %, 8 wt %, 10 wt %, 12 wt %, 14 wt %, 16 wt %, 18 wt %, 20 wt %, 22 wt %, 24 wt %, 26 wt %, 28 wt %, 30 wt %, 32 wt %, 34 wt %, 36 wt %, 38 wt %, 40 wt %, 42 wt %, 44 wt %, 46 wt %, 48 wt %, 50 wt %, 52 wt %, 54 wt %, 56 wt %, 58 wt %, or 60 wt % relative to a total weight of the lithium-rich molten metal alloy. In some embodiments, the lithium-rich molten metal alloy comprises lithium of at most about 0.1 weight % (wt %), 0.2 wt %, 0.4 wt %, 0.6 wt %, 0.8 wt %, 1 wt %, 2 wt %, 4 wt %, 6 wt %, 8 wt %, 10 wt %, 12 wt %, 14 wt %, 16 wt %, 18 wt %, 20 wt %, 22 wt %, 24 wt %, 26 wt %, 28 wt %, 30 wt %, 32 wt %, 34 wt %, 36 wt %, 38 wt %, 40 wt %, 42 wt %, 44 wt %, 46 wt %, 48 wt %, 50 wt %, 52 wt %, 54 wt %, 56 wt %, 58 wt %, 60 wt %, 62 wt %, 64 wt %, 66 wt %, 68 wt %, or 70 wt % relative to a total weight of the lithium-rich molten metal alloy.

[0068] In some embodiments, the potential applied across the anode 40 and the layer of molten metal 30 is at least about 3V, 4V, 5V, 6V, 7V, 8V, 9V, 10V, 11V, or 12V. In some embodiments, the potential applied across the anode 40 and the layer of molten metal 30 is at most about 3V, 4VV, 6V, 7V, 8V, 9V, 10V, 11V, or 12V. In some embodiments, the potential applied across the anode 40 and the layer of molten metal 30 is about 3V to 12V, 4V to 9V, 5V to 8V, or 6V to 7V.

[0069] In some embodiments, an amount of the lithium transferred from the borate melt to the molten metal comprises at least about 0.1 mg/hr, 0.5 mg/hr, 1 mg/hr, 5 mg/hr, 10 mg/hr, 50 mg/hr, 100 mg/hr, 150 mg/hr, 200 mg/hr, 250 mg/hr, 300 mg/hr, 350 mg/hr, 400 mg/hr, 450 mg/hr, 500 mg/hr, 550 mg/hr, 600 mg/hr, 650 mg/hr, 700 mg/hr, 750 mg/hr, 800 mg/hr, 850 mg/hr, 900 mg/hr, 950 mg/hr, 1,000 mg/hr, 1,200 mg/hr, 1,400 mg/hr, 1,600 mg/hr, 1,800 mg/hr, 2,000 mg/hr, 2,500 mg/hr, 3,000 mg/hr, 3,500 mg/hr, 4,000 mg/hr, 4,500 mg/hr, 5,000 mg/hr, 5,500 mg/hr, 6,000 mg/hr, 6,500 mg/hr, 7,000 mg/hr, 7,500 mg/hr, 8,000 mg/hr, 8,500 mg/hr, 9,000 mg/hr, 9,500 mg/hr, 10,000 mg/hr, 20,000 mg/hr, 30,000 mg/hr, 40,000 mg/hr, 50,000 mg/hr, 60,000 mg/hr, 70,000 mg/hr, 80,000 mg/hr, 90,000 mg/hr, 100,000 mg/hr, 110,000 mg/hr, or 120,000 mg/hr. In some embodiments, an amount of the lithium transferred from the borate melt to the molten metal comprises at most about 0.1 mg/hr, 0.5 mg/hr, 1 mg/hr, 5 mg/hr, 10 mg/hr, 50 mg/hr, 100 mg/hr, 150 mg/hr, 200 mg/hr, 250 mg/hr, 300 mg/hr, 350 mg/hr, 400 mg/hr, 450 mg/hr, 500 mg/hr, 550 mg/hr, 600 mg/hr, 650 mg/hr, 700 mg/hr, 750 mg/hr, 800 mg/hr, 850 mg/hr, 900 mg/hr, 950 mg/hr, 1,000 mg/hr, 1,200 mg/hr, 1,400 mg/hr, 1,600 mg/hr, 1,800 mg/hr, 2,000 mg/hr, 2,500 mg/hr, 3,000 mg/hr, 3,500 mg/hr, 4,000 mg/hr, 4,500 mg/hr, 5,000 mg/hr, 5,500 mg/hr, 6,000 mg/hr, 6,500 mg/hr, 7,000 mg/hr, 7,500 mg/hr, 8,000 mg/hr, 8,500 mg/hr, 9,000 mg/hr, 9,500 mg/hr, 10,000 mg/hr, 20,000 mg/hr, 30,000 mg/hr, 40,000 mg/hr, 50,000 mg/hr, 60,000 mg/hr, 70,000 mg/hr, 80,000 mg/hr, 90,000 mg/hr, 100,000 mg/hr, 110,000 mg/hr, or 120,000 mg/hr.

[0070] The molten salt of the second stage is formulated to be liquid at the operating temperature of the cell. In some embodiments, the temperature of the molten salt of the second stage is between about 300? C. and about 800? C. In some embodiments, the temperature of the molten salt of the second stage is higher than about 200? C., 250? C., 300? C., 350? C., 400? C., 450? C., 500? C., 550? C., 600? C., 650? C., 700? C., 750? C., 800? C., 850? C., or 900? C. In some embodiments, the temperature of the molten salt of the second stage is lower than about 200? C., 250? C., 300? C., 350? C., 400? C., 450? C., 500? C., 550? C., 600? C., 650? C., 700? C., 750? C., 800? C., 850? C., or 900? C. In some embodiments, the temperature of the molten salt of the second stage is between about 200? C. and 900? C., between about 250? C. and 850? C., between about 300? C. and 800? C., between about 350? C. and 750? C., between about 400? C. and 700? C., between about 450? C. and 650? C., between about 500? C. and 600? C., or between about 550? C. and 750? C.

[0071] In some embodiments, the molten salt includes, but not limited to LiCl, KCl, RbCl, CsCl, SrCl.sub.2, BaCl.sub.2, and combinations thereof. In some embodiments, the molten salt formulation comprises fluoride salts. In some embodiments the molten salt formulation comprises fluoride salts with highly cathodic decomposition potentials. In some such embodiments, the fluoride salts include, but not limited to LiF, CaF.sub.2, and combinations thereof. In some embodiments, the molten salt electrolyte is free of oxides. In some embodiments, the molten salt electrolyte has the molten salt electrolyte may have small (trace) amounts of oxides present. In some embodiments, the method disclosed herein may work with small (trace) amounts of oxides present. In some embodiments, the molten salt electrolyte may comprise oxides of at least about 0.01 wt % to about 5 wt %. In some embodiments, the molten salt electrolyte may comprise oxides of at most about 0.01 wt % to about 5 wt %.

[0072] In preferred embodiments, the molten salt is formulated to be a liquid at the desired operating temperature. In some embodiments, the melting temperature of the molten salt electrolyte is higher than about 100? C., 95? C., 90? C., 85? C., 80? C., 75? C., 70? C., 65? C., 60? C., 55? C., 50? C., 45? C., 40? C., 35? C. or 30? C. In some embodiments, the melting temperature of the molten salt electrolyte is higher than about 100? C. In some embodiments, the melting temperature of the molten salt electrolyte is higher than about 75? C. In some embodiments, the melting temperature of the molten salt electrolyte is higher than about 50? C. In some embodiments the melting temperature of the molten salt electrolyte is higher than about 30? C. In some embodiments, the melting temperature of the molten salt electrolyte is lower than about 100? C., 95? C., 90? C., 85? C., 80? C., 75? C., 70? C., 65? C., 60? C., 55? C., 50? C., 45? C., 40? C., 35? C. or 30? C. In some embodiments, the melting temperature of the molten salt electrolyte is lower than about 100? C. In some embodiments, the melting temperature of the molten salt electrolyte is lower than about 75? C. In some embodiments, the melting temperature of the molten salt electrolyte is lower than about 50? C. In some embodiments the melting temperature of the molten salt electrolyte is lower than about 30? C.

[0073] In some embodiments, for the second stage, the cathode is a conductive substrate. In some embodiments, the cathode comprises a current collector. In some embodiments, the current collector comprises carbonaceous material, Ti, Al, Cu, Ni, stainless steel, or combinations thereof. In some embodiments, the cathode comprises a metal current collector. In some embodiments, the cathode comprises a carbon current collector. In some embodiments, the cathode comprises a lithium absorption electrode comprising graphite or metals that alloy with lithium. In some embodiments, the cathode comprises an electrically conductive slurry comprising an electrically conductive additive.

[0074] In some embodiments, the potential applied across the cathode 80 and the alloy of molten metal and lithium is at least about 3V, 4V, 5V, 6V, 7V, 8V, 9V, 10V, 11V, or 12V. In some embodiments, the potential applied across the cathode 80 and the alloy of molten metal and lithium is at most about 3V, 4VV, 6V, 7V, 8V, 9V, 10V, 11V, or 12V. In some embodiments, the potential applied across the cathode 80 and the alloy of molten metal and lithium is about 3V to 12V, 4V to 9V, 5V to 8V, or 6V to 7V.

[0075] In some embodiments, an amount of the lithium transferred from the alloy of molten metal and lithium to the cathode comprises at least about 0.1 mg/hr, 0.5 mg/hr, 1 mg/hr, 5 mg/hr, 10 mg/hr, 50 mg/hr, 100 mg/hr, 150 mg/hr, 200 mg/hr, 250 mg/hr, 300 mg/hr, 350 mg/hr, 400 mg/hr, 450 mg/hr, 500 mg/hr, 550 mg/hr, 600 mg/hr, 650 mg/hr, 700 mg/hr, 750 mg/hr, 800 mg/hr, 850 mg/hr, 900 mg/hr, 950 mg/hr, 1,000 mg/hr, 1,200 mg/hr, 1,400 mg/hr, 1,600 mg/hr, 1,800 mg/hr, 2,000 mg/hr, 2,500 mg/hr, 3,000 mg/hr, 3,500 mg/hr, 4,000 mg/hr, 4,500 mg/hr, 5,000 mg/hr, 5,500 mg/hr, 6,000 mg/hr, 6,500 mg/hr, 7,000 mg/hr, 7,500 mg/hr, 8,000 mg/hr, 8,500 mg/hr, 9,000 mg/hr, 9,500 mg/hr, 10,000 mg/hr, 20,000 mg/hr, 30,000 mg/hr, 40,000 mg/hr, 50,000 mg/hr, 60,000 mg/hr, 70,000 mg/hr, 80,000 mg/hr, 90,000 mg/hr, 100,000 mg/hr, 110,000 mg/hr, or 120,000 mg/hr. In some embodiments, an amount of the lithium transferred from the alloy of molten metal and lithium to the cathode comprises at most about 0.1 mg/hr, 0.5 mg/hr, 1 mg/hr, 5 mg/hr, 10 mg/hr, 50 mg/hr, 100 mg/hr, 150 mg/hr, 200 mg/hr, 250 mg/hr, 300 mg/hr, 350 mg/hr, 400 mg/hr, 450 mg/hr, 500 mg/hr, 550 mg/hr, 600 mg/hr, 650 mg/hr, 700 mg/hr, 750 mg/hr, 800 mg/hr, 850 mg/hr, 900 mg/hr, 950 mg/hr, 1,000 mg/hr, 1,200 mg/hr, 1,400 mg/hr, 1,600 mg/hr, 1,800 mg/hr, 2,000 mg/hr, 2,500 mg/hr, 3,000 mg/hr, 3,500 mg/hr, 4,000 mg/hr, 4,500 mg/hr, 5,000 mg/hr, 5,500 mg/hr, 6,000 mg/hr, 6,500 mg/hr, 7,000 mg/hr, 7,500 mg/hr, 8,000 mg/hr, 8,500 mg/hr, 9,000 mg/hr, 9,500 mg/hr, 10,000 mg/hr, 20,000 mg/hr, 30,000 mg/hr, 40,000 mg/hr, 50,000 mg/hr, 60,000 mg/hr, 70,000 mg/hr, 80,000 mg/hr, 90,000 mg/hr, 100,000 mg/hr, 110,000 mg/hr, or 120,000 mg/hr.

[0076] In some embodiments, when a current 90 is applied across the cathode 80 and the alloy of molten metal and lithium, Li.sup.+ is released from the alloy and reduced to form a layer of lithium metal 100 at the cathode 80. In some embodiments, a thickness of the lithium metal layer on the cathode may be at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 ?m. In some embodiments, a thickness of the lithium metal layer on the cathode may be at least about 1, 5, 10, 20, 30, 40, 50, 100, 200, 300, 400, or 500 ?m. In some embodiments, a thickness of the lithium metal layer on the cathode may be at most about 1, 5, 10, 20, 30, 40, 50, 100, 200, 300, 400, or 500 ?m. In some embodiments, a thickness of the lithium metal layer on the cathode may be about between 1 and 380 ?m, between 1 and 370 ?m, between 1 and 360 m, between 1 and 350 ?m, between 1 and 340 ?m, between 1 and 330 ?m, between 1 and 320 ?m, between 1 and 310 ?m, between 1 and 300 ?m, between 1 and 250 ?m, between 1 and 200 ?m, between 1 and 150 ?m, between 1 and 100 ?m, between 1 and 90 ?m, between 1 and 80 ?m, between 1 and 70 ?m, between 1 and 60 ?m, between 1 and 50 ?m, between 1 and 45 ?m, between 1 and 40 ?m, between 1 and 35 ?m, between 1 and 30 ?m, between 1 and 25 ?m, between 1 and 20 ?m, between 1 and 15 ?m, between 1 and 10 ?m, or between 1 and 5 ?m.

[0077] In some embodiments, the density of the lithium metal deposited ranges from about 0.2 g/cm.sup.3 to 0.534 g/cm.sup.3. In some embodiments, the density of the lithium metal deposited is at least about 0.2, 0.22, 0.24, 0.26, 0.28, 0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, or 0.534 g/cm.sup.3. In some embodiments, the density of the lithium metal deposited is at most about 0.2, 0.22, 0.24, 0.26, 0.28, 0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, or 0.534 g/cm.sup.3.

[0078] As embodied in FIG. 3, as the lithium metal is reduced at the cathode, it remains in a molten state and floats to the top of the cell, forming a layer of liquid lithium metal 100. The liquid layer of lithium metal 100 can be recovered from the top of the molten salt electrolyte 70 by siphoning off, by dipping onto a colder substrate, or by allowing the layer of lithium metal to cool around the cathode. In some embodiments, the cathode 80 includes a material selected from the group consisting of nickel, copper, carbon, titanium, and combinations thereof. In some embodiments, the cathode 80 is a nickel mesh. In some embodiments, the lithium metal layer forms around the cathode 80, so that upon cooling it provides a lithium metal electrode. In some embodiments, the lithium metal layer may be treated by refining or post processes.

[0079] In some embodiments, the method disclosed herein may be used for a scale-up production.

[0080] The embodiments of the disclosure described above are intended to be merely exemplary; numerous variations and modifications will be apparent to those skilled in the art. All such variations and modifications are intended to be within the scope of the present disclosure as defined in any appended claims.

LIST OF EMBODIMENTS

[0081] The following list of embodiments of the invention are to be considered as disclosing various features of the invention, which features can be considered to be specific to the particular embodiment under which they are discussed, or which are combinable with the various other features as listed in other embodiments. Thus, simply because a feature is discussed under one particular embodiment does not necessarily limit the use of that feature to that embodiment.

Embodiment 1. A process for extracting lithium from a lithium ion containing material comprising the steps of. [0082] dissolving the lithium ion containing material in a borate melt; [0083] disposing the borate melt and a molten metal in a first cell, the molten metal being denser than the borate melt and forming a layer of molten metal below the borate melt; [0084] immersing an anode in the first cell; [0085] applying voltage across the anode and the layer of molten metal so that lithium ion is reduced to lithium metal at the layer of molten metal, thereby forming an alloy of the molten metal with the lithium metal at the bottom of the first cell; [0086] disposing the alloy of the molten metal at the bottom of a second cell; [0087] disposing a molten salt electrolyte on top of the alloy of molten metal, the molten salt electrolyte being free of oxides; [0088] immersing a cathode in the molten salt electrolyte; [0089] applying a voltage across the cathode and the alloy of molten metal, so that lithium ion is released from the alloy of molten metal and is reduced to lithium metal at the cathode.
Embodiment 2. The process of Embodiment 1 wherein the lithium ion containing material comprises a lithium ore.
Embodiment 3. The process of Embodiment 2 wherein the lithium ore includes spodumene.
Embodiment 4. The process of Embodiment 1 wherein the anode in the first cell comprises carbon.
Embodiment 5. The process of Embodiment 1 wherein the borate melt includes a fluoride.
Embodiment 6. The process of Embodiment 5 wherein the fluoride is selected from the group consisting of NaF, KF, CaF.sub.2, and combinations thereof.
Embodiment 7. The process of Embodiment 1 wherein the first cell is kept at a temperature between 600 and 1000? C.
Embodiment 8. The process of Embodiment 1 wherein the second cell is kept at a temperature between 300 and 800? C.
Embodiment 9. The process of Embodiment 1 wherein the cathode is an inert material.
Embodiment 10. The process of Embodiment 9, wherein the cathode comprises a material selected from the group consisting of nickel, copper, titanium, and carbon (graphite).
Embodiment 11. The process of Embodiment 1 wherein the molten salt electrolyte includes salts selected from the group consisting of lithium halides, sodium halides, potassium halides, and combinations thereof.
Embodiment 12. The process of Embodiment 1 wherein the molten salt electrolyte includes salts selected from the group consisting of LiCl, KCl, RbCl, CsCl, SrCl.sub.2, BaCl.sub.2, and combinations thereof.
Embodiment 13. The process of Embodiment 1 wherein the molten salt electrolyte includes fluoride salts.
Embodiment 14. The process of Embodiment 13 wherein the fluoride salts are selected from the group consisting of LiF, CaF.sub.2, and combinations thereof.