Compositions and methods for extracting one or more metals from a solution

Abstract

Disclosed are reagent compositions containing at least one urea extractant and at least one non-urea extractant each capable of selectively extracting one or more metal, compounds thereof, salts thereof or combinations thereof, from an aqueous solution; and optionally at least one modifier and / or diluent. Further disclosed are methods of extracting one or more metals from an aqueous solution, including contacting the aqueous solution with a reagent composition as described above; and extracting the one or more metals, compounds thereof, salts thereof, or combinations thereof, from the aqueous solution into the reagent composition until reaching equilibrium to form a metal depleted aqueous phase and a metal rich organic phase.

Description

COMPOSITIONS AND METHODS FOR EXTRACTING ONE OR MORE METALSFROM A SOLUTIONFIELD

[0001] The disclosure relates to reagent compositions and methods for extracting one or more metals from a solution using such reagent compositions.BACKGROUND

[0002] In the world’s transition to clean energy, electricity storage platforms play an important role. Lithium batteries are at the forefront of electricity storage technologies because inter alia they charge faster, last longer and have a higher power density to provide more battery life in a lighter package than conventional batteries. Lithium storage devices are useful for electrification of the transportation sector, electric vehicles, battery storage for electric utilities and in many other applications to reduce carbon emissions and store electricity.

[0003] Lithium, including lithium metal, lithium compounds, and / or lithium salts, is typically extracted from underground deposits of brine water and lithium-containing ore. Brines from salars and salt lakes, as well as spodumene ores, are the primary sources of lithium, while geothermal brines represent secondary sources. Classical methods of lithium extraction rely on brine evaporation in open ponds to maximize element concentration for further purification; however, these methods are very slow (evaporation of ponds to the desired level can take up to 24 months) and strongly dependent on region-specific weather conditions that vary throughout the year. Newer technologies based on precipitation, adsorption, solvent extraction, and membranes can be used for brine concentration and may increase the economic viability of minerals extracted from seawater and other geothermal brines. However, there is a need for improved compositions and methods for recovering lithium from aqueous solutions and / or ore.BRIEF SUMMARY

[0004] According to one or more embodiments, described herein are reagent compositions, comprising: at least one urea extractant capable of selectively extracting one or more metals, compounds (i.e., other than salts) thereof, salts thereof, or combinations thereof, from an aqueous solution; and at least one non-urea extractant capable of selectively extracting one or more metals, compounds thereof, salts thereof, or combinations thereof, from the aqueous solution. The at least one urea extractant and the at least one non-urea extractant may be suitable extract the same or different metals, compounds thereof, salts thereof, or combinationsthereof. According to embodiments, the one or more metals comprise lithium, magnesium, calcium, boron, potassium, sodium, or combinations thereof. In various embodiments, the one or more metals comprise a lithium salt, magnesium salt, calcium salt, boron salt, potassium salt, sodium salt or combinations thereof. In embodiments, the one or more metals comprise lithium or a lithium salt (e.g., lithium chloride).

[0005] According to various embodiments, the at least one urea extractant comprises one or more urea compound chosen from the following Formula (I), Formula (II) (i. e. , a thiourea), or combinations thereof:wherein R1, R2, R3and R4is each independently hydrogen, a methyl group, an ethyl group, a straight or branched C3-C20 alkyl group, a C3-C12 cycloalkyl group having a single ring structure, a CT-C 10 aromatic ring group, a C3-C20 alkylphenyl group, a straight or branched C3-C20 alkenyl group, a straight or branched C3-C20 alkynyl group, a thiol group, wherein each of the C3-C20 alkyl, alkenyl or alkynyl groups may be interrupted with N, 0 or S.

[0006] The at least one non-urea extractant comprises an amide compound chosen from the following Formula (III), Formula (IV), Formula (V) (i.e., a sulfonamide), or combinations thereof:wherein R5, R6, R7, R8, R9, R10, R11, R13, R14and R15is each independently hydrogen, a methyl group, an ethyl group, a straight or branched C3-C20 alkyl group, a C3-C12 cycloalkyl group having a single ring structure, a Ce-Cio aromatic ring group, a C1-C20 alkylphenyl group, a dihydrobenzodioxene group, a straight or branched C1-C20 alkanol group, a straight or branched C1-C20 alkyldiol group, a straight or branched C3-C20 alkenyl group, a straight or branched C3-C20 alkynyl group, a thiol group, wherein at least one carbon atom of R5, R6, R7, R8, R9, R10, R11, R13, R14and R15may be substituted with a N, 0 or S, and wherein R12is a bond, a methyl group, an ethyl group, a straight or branched C3-C20 alkyl group, a C3-C12 cycloalkyl group having a single ring structure, a C6-C10 aromatic ring group, a C3-C20 alkylphenyl group, a straight or branched C3-C20 alkenyl group, a straight or branched C3-C20 alkynyl group, a thiol group, wherein at least one carbon atom of R12may be substituted with N, 0 or S.

[0007] In further embodiments, reagent compositions according to embodiments herein may further include diluent. Suitable diluents include, but are not limited to, an alcohol, an organophosphorous solvent, or a combination thereof. In various embodiments, the at least one diluent may be chosen from octanol, trideconal, 2-ethyl-l -hexanol, 3-methyl-l-butanol, isoamyl alcohol, 2-hexyl decanol, octanoic acid, trioctylphosphine oxide (e.g., Cyanex® 923), petroleum distillates solvent (e.g., Orform® SX80), aromatic C9-C10 solvent (e.g., Shellsol® A150), a kerosene (e.g., Orform® SX11), dibutyl carbitol, dichloromethane, trioctylmethylammonium chloride (e.g., Aliquat 336), chloroform, or a combination of any two or more thereof.

[0008] In one or more embodiments, the reagent compositions can include at least one modifier, wherein the at least one modifier comprises one or more functional group having a dipole moment and / or that is attached to a highly polar ionic bond. In embodiments, the at least one modifier comprises an aliphatic component that is attracted to non-polar moieties of the at least one urea extractant and / or the at least one non-urea extractant. The at least one modifier may include one or more functional group chosen from a diether, amide, imide, ketone, alcohol, ether, alkyl phosphine, phosphate, ester, phosphonic acid, phosphonic acid, phosphoric acid and / or nitrile. According to various embodiments, the at least one modifier is chosen from 1,6-di-t-butoxy hexane, di(ethylene glycol) dibutyl ether, 1,4-bis-t-butoxy butane, 2-ethylhexyl succinimide, 4-t-butylcyclohexanone, l-butyl-3-methylimidazolium methyl sulfate, iminodiacetic acid (IDA), dodecanol, 2, 2, 4-trimethyl- 1,3 -pentanediol diisobutyrate (TXIB), ethyoxylated isotridecyl phosphate (TDA), cy decanol, l-methyl-3-octylimidazolium chloride, trihexyltetradecylphosphonium chloride, 1 -decyl-3 -methylimidazoliumtetrafluoroborate, 7-ethyl-2-methyl-undecanol, hexyl 3-methylimidazolium chloride, trimethyl nonanol, 4-isopropyl cyclohexanone, t-butyl octyl ether, 3-isopropyl cyclohexanone, 3,3,5- trimethyl cyclohexanone, methyl n-propyl ketone (e.g., Eastman Cn ketone), 5-ethyl-2- nonanone, amixture of phosphine oxides (e.g., Cyanex 923), tributyl phosphate, 6-undecanone, heptyl 2-ethylbutyrate, 2-ethylbutyl caproate, 3-(cyclohexyl)-propionitrile, di(2- ethylhexyl)phthalate, tris(2-ethylhexyl)phosphate, triisobutyl phosphate, ethyl acetate, or a combination of any two or more thereof.

[0009] In one or more embodiments, the at least one non-urea extractant is present in the reagent composition in an amount of greater than 0 wt%, or about 1 wt% to about 99 wt%, or any individual value or sub-range within these ranges, based on the total weight of the reagent composition. In various embodiments, the at least one non-urea extractant is present in the reagent composition in an amount of greater than 0 wt%, or about 1 wt% to about 99 wt%, or any individual value or sub-range within these ranges, based on the total weight of the reagent composition. According to embodiments, the reagent composition comprises a weight ratio of the at least one urea extractant to the at least one non-urea extractant of about 1: 10 to about 100:1

[0010] In some embodiments, the at least one modifier and / or diluent is present in the reagent composition in an amount of greater than 0 wt%, or about 1 wt% to about 99 wt%, based on the total weight of the reagent composition. A weight ratio of the at least one urea extractant to the at least one modifier and / or diluent is about 1 : 10 to about 100: 1.

[0011] Further described herein are methods of extracting one or more metals (including compounds thereof and salts thereof, e.g., one or more lithium salts) from an aqueous solution, comprising: contacting the aqueous solution with the reagent composition of any preceding claim; and extracting the one or more metals from the aqueous solution into the reagent composition until reaching equilibrium to form a metal depleted aqueous phase and a metal rich organic phase. The aqueous solution may be a metal-containing brine (e.g., a lithium- containing brine), brine from a salar, product stream from a pond evaporation process, product stream from a processing plant, or combinations thereof. In some embodiments, the aqueous solution is contacted with a magnesium selective reagent composition, a boron selective reagent composition, or combinations thereof, prior to contacting the aqueous solution with the reagent composition to extract the one or more lithium salts. In one or more embodiments, the one or more lithium salts comprised in the aqueous solution comprises lithium chloride, lithium sulfate, lithium hydroxide, lithium nitrate or combinations thereof.

[0012] Methods described herein can further include contacting the metal depleted aqueous phase with fresh reagent composition and further extracting the one or more metals from the aqueous solution into the metal rich organic phase until reaching equilibrium. In some embodiments, methods include repeating the further extracting with fresh reagent composition until the metal depleted aqueous phase is free or substantially free of metal.

[0013] In at least one embodiment, the methods further include emulsifying the metal rich organic phase. In various embodiments, the methods include separating the metal depleted aqueous phase from the metal rich organic phase. The methods may further comprise stripping the one or more metals from the metal rich organic phase. In one or more embodiments, about 70% to about 99%, or about 95% of the one or more metals (e.g., lithium as the target metal) is stripped from the metal rich organic phase.

[0014] Methods as described herein are suitable to provide an overall extraction of one or more target metal (e.g., lithium, one or more lithium salt) from the aqueous solution of greater than about 70%, greater than about 80%, greater than about 90%, greater than about 92%, or about 70% to about 99%, or about 80% to about 93%. In various embodiments, the selectivity of the urea extractant for lithium over magnesium in the described methods is about 1 to about 50, about 5 to about 30, or about 10 to about 25.SUMMARY OF THE DRAWINGS

[0015] The present disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like references indicate similar elements.

[0016] FIG. 1 shows a schematic representation of a zwitterionic extractant when contacted with a solution containing inorganic salts forming an inorganic-organic double salt (IODS) can be formed using lithium chloride (LiCl) as an example.Definitions

[0017] Reference throughout this specification to, for example, “one embodiment,” “certain embodiments,” “one or more embodiments” or “an embodiment” means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases such as “in one or more embodiments,” “in certain embodiments,” “in one embodiment” or “In one or more embodiments” in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular features,structures. materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0018] As used herein, the singular forms “a,” “an,” and “the” include plural references unless the context clearly indicates otherwise. Thus, for example, reference to “a depurator vessel” includes a single depurator vessel as well as more than one depurator vessel.

[0019] As used herein, the term “about” in connection with a measured quantity, refers to the normal variations in that measured quantity as expected by one of ordinary skill in the art in making the measurement and exercising a level of care commensurate with the objective of measurement and the precision of the measuring equipment. In certain embodiments, the term “about” includes the recited number ±10%, such that “about 10” would include from 9 to 11.

[0020] The term “at least about” in connection with a measured quantity refers to the normal variations in the measured quantity, as expected by one of ordinary skill in the art in making the measurement and exercising a level of care commensurate with the objective of measurement and precisions of the measuring equipment and any quantities higher than that. In certain embodiments, the term “at least about” includes the recited number minus 10% and any quantity that is higher such that “at least about 10” would include 9 and anything greater than 9. This term can also be expressed as “about 10 or more.” Similarly, the term “less than about” typically includes the recited number plus 10% and any quantity that is lower such that “less than about 10” would include 11 and anything less than 11. This term can also be expressed as “about 10 or less.”

[0021] Unless otherwise indicated, all parts and percentages are by weight. Weight percent (wt. %), if not otherwise indicated, is based on an entire composition free of any volatiles, that is, based on dry solids content.

[0022] The term “metal” or “metals” as used herein refers to the recited metal element and includes compounds (other than salts) containing the metal, salts containing the metal and / or combinations thereof. For example, “lithium” refers to lithium compounds, lithium salts and lithium-containing molecules.

[0023] The term “trace” or “trace amount” as used herein refers to the amount of a component in a solution being less than about 1 part per million by weight (ppmw).

[0024] The term “substantially free” as used herein refers to trace amounts of a component in a fluid, less than trace amounts of the component in the fluid or a non-detectable amount of the component in the fluid.DETAILED DESCRIPTION

[0025] Embodiments of the disclosure are described more fully hereinafter with reference to the accompanying drawings, which form a part hereof, and which show, by way of illustration, example features. The features can, however, be embodied in many different forms and should not be construed as limited to the combinations set forth herein; rather, these combinations are provided so that this disclosure will be thorough and complete and will fully convey the scope. The following detailed description is, therefore, not to be taken in a limiting sense.

[0026] Disclosed herein are embodiments of reagent compositions and methods for extracting lithium salts from an aqueous solution using such reagent compositions. According to one or more embodiments, the reagent compositions include zwitterionic urea extractants and nonurea extractants for use in methods of solvent extraction of one or more alkali metals (e.g., lithium and / or lithium containing compounds such as lithium salts including lithium chloride). The extractants and methods described herein can be highly selective for one or more target metals or metal containing compounds such as metal salts (e.g., lithium chloride). According to one or more embodiments, it was determined that the reagent compositions as described herein are suitable to concentrate the metal and / or metal compounds (e.g., LiCl) dramatically with a selectivity that was far greater than expected.

[0027] The solvent extraction methods according various embodiments herein are operable using a conventional solvent extraction process and the system is suitable for stripping with water to a relatively high concentration of metal or metal compounds (e.g., lithium chloride) in the recovery solution. It has been found that the extraction of the metals and metal-containing compounds and the production of a recovery stream containing the concentrated metals and / or compounds is suitable for downstream use as battery grade (e.g., lithium salt) production.

[0028] Urea extractants and non-urea extractants as described herein may be zwitterionic extractants having a positive charge and a negative charge on the same organic molecule. This makes these compounds intra-ion organic salts, and are often self-associating in the bulk organic. When contacted with a solution containing inorganic salts, an inorganic-organic double salt (IODS) can be formed as shown in FIG. 1 using lithium chloride (LiCl) as an example. Without being bound by any particular theory, it is believed that transfer of the LiCl occurs by making an emulsion to increase the surface area. The extractant is suitable to bond with the lithium salt at the interface forming the IODS. The emulsion may be allowed to coalesce once extraction is complete so the phases can be separated. The organic solution is typically washed or scrubbed to remove entrained water or loaded impurities. It is then strippedwith water. This is considered an aty pical liquid-liquid solvent extraction process due to the lack of an activation / deactivation mechanism using acid / base.

[0029] While most extractants need a diluent or solvent in order to remain low viscosity, zwitterions can work essentially as neat formulations of extractant and modifier. In embodiments, the unloaded formulation is a three-component system: at least one urea extractant, at least one non-urea extractant and at least one modifier. The urea extractant, nonurea extractant, modifier and their respective concentrations may be chosen based on a particular aqueous solution containing one or more target metals, compounds thereof, salts thereof, or combinations thereof.Reagent Compositions

[0030] Described herein according to one or more embodiments are reagent compositions comprising one or more extractant(s) that are selective for one or more target metals including compounds thereof, salts thereof, and / or combinations thereof. For example, the reagent compositions contain at least one urea extractant and at least one non-urea extractant both suitable to extract lithium and / or lithium salts. Suitable extractants include urea extractants, for example, containing a urea compound and / or a urea base structure including a thiourea, and non-urea extractants such as amide extractants, for example, containing an amide compound and / or an amide base structure including sulfonamides.

[0031] In embodiments described herein, the urea and non-urea extractants do not use a proton transfer mechanism. Without being bound by any particular theory, it is believed that extractants as described herein work by inducing a zwitterionic charge based on resonance structures. The extractants described herein may be suitable to extract lithium as a salt (e.g., lithium chloride, etc.). In various embodiments, the reagent compositions may be free of an extractant that uses a proton transfer mechanism.

[0032] The one or more target metals or metal compounds may be dissolved and / or dispersed within a solvent (e.g., an aqueous solution). In various embodiments, the solvent is a metalcontaining aqueous solution, for example, a metal-containing brine, brine from a salar, product stream from a pond evaporation process, product stream from a processing plant, or combinations thereof. According to various embodiments, the aqueous solution is a brine containing greater than about 60,000 ppm of magnesium, compounds thereof, salts thereof, or combinations thereof, and at least about 150 ppm of lithium, compounds thereof, salts thereof, or combinations thereof.

[0033] In some embodiments, the at least one urea extractant and the at least one non-urea extractant are independently capable of selectively extracting lithium, magnesium, calcium, boron, potassium, or sodium, or combinations thereof. In some embodiments, the at least one urea extractant and at least one non-urea extractant are independently capable of selectively extracting one or more lithium compounds, one or more magnesium compounds, one or more calcium compounds, one or more boron compounds, one or more potassium compounds, or one or more sodium compounds, or combinations thereof. For example, suitable extractants may be capable of extracting one or more lithium salt, one or more magnesium salt, one or more calcium salt, one or more boron salt, one or more potassium salt, or one or more sodium salt, or combinations thereof. According to embodiments, suitable extractants are capable of selectively extracting, lithium, one or more lithium compounds such as one or more lithium salts, or combinations thereof. In various embodiments, the at least one urea extractant and at least one non-urea extractant selectively extract a lithium salt over one or more magnesium salts, one or more calcium salts, one or more boron salts, one or more potassium salts, or one or more sodium salts, and / or combinations thereof.

[0034] Suitable urea extractants for use in reagent compositions as described herein include one or more urea compound having the following formula (I), formula (II), or combinations thereof:wherein R1, R2, R3and R4is each independently hydrogen, a methyl group, an ethyl group, a straight or branched C3-C20 alkyl group, a C3-C12 cycloalkyl group having a single ring structure, a Cs-Cio aromatic ring group, a C3-C20 alkylphenyl group, a straight or branched C3-C20 alkenyl group, a straight or branched C3-C20 alkynyl group, a thiol group, wherein each of the C3-C20 alkyl, alkenyl or alkynyl groups may be interrupted with N, 0 or S. In some embodiments, at least one urea extractant is of Formula (I) wherein R3and R4are H. In one or more embodiments, at least one urea extractant is of Formula (I) wherein R1, R2or both are a Ce aromatic ring structure. In some embodiments, R1is a branched Cs alkyl or a branched Cs alkyl.

[0035] In some embodiments, at least one urea extractant in the reagent composition is of Formula (I), wherein R1is a branched Cs-Cs alkyl, R2is a Ce aromatic ring and R3and R4are H. In some embodiments, at least one urea extractant is of Formula (I) wherein R1and R2are a Ce aromatic ring and R3and R4are H. In one or more embodiments, at least one urea extractant is of Formula (I) wherein R1and R2are independently a straight or branched Ce-Cs alkyl and R3and R4are H. In some embodiments, at least one urea extractant in the reagent composition is of Formula (II) wherein R1and R3are a straight or branched Cs-Cs alkyl, and R2and R4are H.

[0036] According to various embodiments, the at least one urea extractant may be present in the reagent composition in an amount of about 5 wt% to about 100 wt%, about 10 wt% to about 90 wt%, about 20 wt% to about 800 wt%, about 30 wt% to about 70 wt%, about 40 wt% to about 50 wt%, about 10 wt% to about 50 wt%, or any individual value or sub-range within these ranges, based on the total weight of the reagent composition. In some embodiments, the urea extractant is present in the reagent composition in an amount of at least about 5 wt%, at least about 10 wt%, at least about 15 wt%, at least about 20 wt%, at least about 25 wt%, at least about 30 wt%, at least about 40 wt%, at least about 50 wt%, or any individual value or subrange within these ranges. In one or more embodiments, the urea extractant is present in the reagent composition in an amount of about 45 wt%, about 46 wt%, about 47 wt%, about 48 wt%, about 49 wt%, about 50 wt%, about 51 wt%, about 52 wt%, about 53 wt%, about 54 wt, or about 55 wt%. In some embodiments, the urea extractant is present in the reagent composition in an amount of about 50 wt%.

[0037] Suitable non-urea extractants for use in reagent compositions as described herein include one or more urea compound having the following Formula (III), Formula (IV), Formula (V), or combinations thereof:whereineach independently hydrogen, a methyl group, an ethyl group, a straight or branched C3-C20 alkyl group, a C3-C12 cycloalkyl group having a single ring structure, a CV-C 10 aromatic ring group, a C1-C20 alkylphenyl group, a dihydrobenzodioxene group, a straight or branched C1-C20 alkanol group, a straight or branched C1-C20 alkyldiol group, a straight or branched C3-C20 alkenyl group, a straight or branched C3-C20 alkynyl group, a thiol group, wherein at least one carbon atom of R5, R6, R7, R8, R9, R10, R11, R13, R14and R15may be substituted with a N, 0 or S, and wherein R12is a bond, a methyl group, an ethyl group, a straight or branched C3-C20 alkyl group, a C3-C12 cycloalkyl group having a single ring structure, a Ce-Cio aromatic ring group, a C3-C20 alkylphenyl group, a straight or branched C3-C20 alkenyl group, a straight or branched C3-C20 alkynyl group, a thiol group, wherein at least one carbon atom of R12may be substituted with N, 0 or S. In one or more embodiments, R6is H. In various embodiments, R5, R7or both are a straight or branched C3-C8 alkyl. In some embodiments, R5is a branched Cs alkyl or a branched Cs alkyl. In various embodiments, R7may be a branched C4 alkyl.

[0038] In some embodiments, at least one non-urea extractant in the reagent composition is of Formula (III), wherein R5and R7are each independently a straight or branched C3-C8 alkyl and R6is H. In some embodiments, at least one non-urea extractant is of Formula (IV) wherein R8and R10are each independently a straight or branched C3-C8 alkyl, R9and R11are H, and R12is a Cs-Ce cycloalkyl. In one or more embodiments, at least one non-urea extractant is of Formula (III) wherein R5is a straight or branched C3-C8 alkyl, R6is H and R7is methyl. In some embodiments, at least one non-urea extractant in the reagent composition is of Formula (III) wherein R5is H, R6and R7 is each independently a straight or branched C3-C8 alkyl. In embodiments, at least one non-urea extractant is of Formula (III) wherein R5is a straight or branched C3-C8 alkyl, R6is H, and R7is an ethyl group. In embodiments, at least one non-urea extractant is of Formula (III) wherein R5is a CR aromatic ring group, R6is H, and R7is a methyl group. In further embodiments, at least one non-urea extractant is of Formula (III) wherein R? is H, R6a Ci alkylphenyl group, and R7is a straight or branched C3-C8 alkyl group. In embodiments, at least one non-urea extractant is of Formula (IV) wherein R8, R9and R10are H, R12is a bond, and R11is a straight or branched C3-C8 alkyl. In various embodiments, atleast one non-urea extractant is of Formula (III) wherein R5is a straight or branched Cs-Cs alkyl, R6is H and R7is a dihydrobenzodioxene group. In embodiments, at least one non-urea extractant is of Formula (III) wherein R5is a Ce aromatic ring group, R6is H, and R7is a straight or branched C3-C8 alkyl. In yet further embodiments, at least one non-urea extractant is of Formula (III), wherein R5and R6are H, and R7is a C3-C8 alkyldiol group. In further embodiments, at least one non-urea extractant is of Formula (III) wherein R5is an 0 substituted C3-C8 alkanol, R6is H, and R7is a straight or branched Cs-Cs alkyl. In yet further embodiments, at least one non-urea extractant is of Formula (V) wherein R13is H and R14and R15is each independently a straight or branched Ci-Cs alkyl.

[0039] According to various embodiments, the at least one non-urea extractant may be present in the reagent composition in an amount of about 5 wt% to about 100 wt%, about 10 wt% to about 90 wt%, about 20 wt% to about 800 wt%, about 30 wt% to about 70 wt%, about 40 wt% to about 50 wt%, about 10 wt% to about 50 wt%, or any individual value or sub-range within these ranges, based on the total weight of the reagent composition. In some embodiments, the non-urea extractant is present in the reagent composition in an amount of at least about 5 wt%, at least about 10 wt%, at least about 15 wt%, at least about 20 wt%, at least about 25 wt%, at least about 30 wt%, at least about 40 wt%, at least about 50 wt%, or any individual value or sub-range within these ranges. In one or more embodiments, the non-urea extractant is present in the reagent composition in an amount of about 45 wt%, about 46 wt%, about 47 wt%, about 48 wt%, about 49 wt%, about 50 wt%, about 51 wt%, about 52 wt%, about 53 wt%, about 54 wt, or about 55 wt%. In some embodiments, the non-urea extractant is present in the reagent composition in an amount of about 50 wt%. According to embodiments, the reagent composition comprises a weight ratio of the at least one urea extractant to the at least one non- urea extractant of about 1: 10 to about 100: 1

[0040] According to one or more embodiments, the reagent compositions described herein further include at least one modifier, at least one diluent, or a combination thereof. “Modifiers” refer to chemical compounds designed to affect the properties of other molecules, materials and / or solutions. “Diluents” refer to one or more substance that is added to the reagent compositions to alter the concentration of other components (e.g., one or more extractant, one or more modifier) contained therein and / or to alter the viscosity of the reagent composition.

[0041] Modifiers as described herein may be used to stabilize the IODS. This can be helpful as the polarity of the organic solvent is not high enough to stabilize the highly ionic character of the IODS. Suitable modifiers for inclusion in reagent compositions as described herein include compounds having one or more functional group with a dipole moment and / or that areattached to a highly polar ionic bond. This may “shield’' the ionic moieties and helps to solubilize the IODS. In various embodiments, the at least one modifier has an aliphatic component that is attracted to non-polar moieties of the at least one urea extractant and / or at least one non-urea extractant. In various embodiments, the at least one modifier includes one or more functional group chosen from a diether, imide, ketone, alcohol, ether, alkyl phosphine, phosphate, ester, phosphonic acid, phosphonic acid, phosphoric acid and / or nitrile.

[0042] Suitable modifiers for use in reagent compositions as described herein may be chosen from 1,6-di-t-butoxy hexane, di(ethylene glycol) dibutyl ether, 1,4-bis-t-butoxy butane, 2- ethylhexyl succinimide, 4-t-butylcyclohexanone, l-butyl-3-methylimidazolium methyl sulfate, iminodiacetic acid (IDA), dodecanol, 2,2,4-trimethyl-l,3-pentanediol diisobutyrate (TXIB), ethoxylatedisotridecyl phosphate (TDA), cy decanol, l-methyl-3-octylimidazolium chloride, trihexyltetradecylphosphonium chloride, l-decyl-3-methylimidazolium tetrafluoroborate, 7- ethyl-2-methyl-undecanol, hexyl 3-methylimidazolium chloride, tnmethyl nonanol, 4- isopropyl cyclohexanone, t-butyl octyl ether, 3-isopropyl cyclohexanone, 3,3,5-trimethyl cyclohexanone, methyl n-propyl ketone (e.g., Eastman Cn ketone), 5-ethyl-2-nonanone, a mixture of phosphine oxides (e.g., Cyanex 923), tributyl phosphate, 6-undecanone, heptyl 2- ethylbutyrate, 2-ethylbutyl caproate, 3-(cyclohexyl)-propionitrile, di(2-ethylhexyl)phthalate, tris(2-ethylhexyl)phosphate, triisobutyl phosphate, ethyl acetate, or a combination of any two or more thereof.

[0043] According to various embodiments, the at least one modifier is present in the reagent composition in an amount of about 0 wt% to about 95 wt%, about 5 wt% to about 80 wt%, about 10 wt% to about 80 wt%, about 20 wt% to about 70 wt%, about 30 wt% to about 60 wt%, about 50 wt% to about 90 wt%, or any individual value or sub-range within these ranges, based on the total weight of the reagent composition. In some embodiments, the modifier is present in the reagent composition in an amount of at least about 25 wt%, at least about 30 wt%, at least about 40 wt%, at least about 50 wt%, or any individual value or sub-range within these ranges. In one or more embodiments, the modifier is present in the reagent composition in an amount of about 40 wt%, about 41 wt%, about 42 wt%, about 43 wt%, about 44 wt%, about 45 wt%, about 46about 47 wt%, about 48 wt%, about 49 wt%, about 50 wt%, about 51 wt%, or about 52 wt%. In some embodiments, the modifier is present in the reagent composition in an amount of about 50 wt%.

[0044] In various embodiments, the weight ratio of the urea extractant to the modifier in the reagent composition is about 1: 100 to about 100:1, about 1:90 to about 90: 1, about 1 :80 to about 80: 1, about 1: 70 to about 70:1, about 1:60 to about 60:1, about 1:50 to about 50: 1, about1:40 to about 40: 1, about 1 :30 to about 30: 1, about 1:25 to about 25: 1, about 1:20 to about 20: 1, about 1:15 to about 15:1, about 1: 10 to about 10: 1, about 1:5 to about 5: 1, about 1:2 to about 1 :2, about 1: 10 to about 100: 1, or any individual value or sub-range within these ranges. In some embodiments, the weight ratio of the urea extractant to the modifier is at least about 1: 10, at least about 1:5, at least about 1:2, at least about 1: 1, at least about 2:1, at least about 5: 1, at least about 10: 1, or any individual value or sub-range within these ranges.

[0045] In various embodiments, the weight ratio of the non-urea extractant to the modifier in the reagent composition is about 1 :100 to about 100:1, about 1:90 to about 90: 1, about 1:80 to about 80: 1, about 1: 70 to about 70:1, about 1:60 to about 60:1, about 1:50 to about 50: 1, about 1:40 to about 40: 1, about 1 :30 to about 30: 1, about 1:25 to about 25: 1, about 1:20 to about 20: 1, about 1:15 to about 15:1, about 1: 10 to about 10: 1, about 1:5 to about 5: 1, about 1:2 to about 1 :2, about 1: 10 to about 100: 1, or any individual value or sub-range within these ranges. In some embodiments, the weight ratio of the non-urea extractant to the modifier is at least about 1:10, at least about 1:5, at least about 1:2, at least about 1 : 1, at least about 2: 1, at least about 5:1, at least about 10:1, or any individual value or sub-range within these ranges.

[0046] Suitable diluents include, but are not limited to, an alcohol, an organophosphorous solvent, or a combination thereof. In various embodiments, the at least one diluent may be chosen from octanol, trideconal, 2-ethyl-l -hexanol, 3-methyl-l-butanol, isoamyl alcohol, 2- hexyl decanol, octanoic acid, trioctylphosphine oxide (e.g., Cyanex® 923), petroleum distillates solvent (e.g., Orform® SX80), aromatic C9-C10 solvent (e.g., Shellsol® A150), a kerosene (e.g., Orform® SX11), dibutyl carbitol, di chloromethane, trioctylmethylammonium chloride (e.g., Aliquat 336), chloroform, or a combination of any two or more thereof.

[0047] According to various embodiments, the at least one diluent is present in the reagent composition in an amount of about 0 wt% to about 90 wt%, about 5 wt% to about 80 wt%, about 10 wt% to about 70 wt%, about 20 wt% to about 60 wt%, about 40 wt% to about 50 wt%, or any individual value or sub-range within these ranges, based on the total weight of the reagent composition. In one or more embodiments, the diluent is present in the reagent composition in an amount of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, or about 10 wt%. In some embodiments, the diluent is present in the reagent composition in an amount of about 0 wt% or less than about 1 wt%.Methods of Preparation

[0048] Reagent compositions according to embodiments herein are comprised of a urea extractant, a non-urea extractant and optionally may be combined with at least one modifier and / or at least one diluent. In some embodiments, a diluent is combined with the urea extractant and / or the non-urea extractant, for example, to provide atarget reagent concentration and / or to provide a target viscosity. Suitable reagent concentrations for a urea extractant or a non-urea extractant in a diluent are about 1 wt% to about 99 wt%, or any individual value or sub-range within these ranges. In some embodiments, the viscosity of the urea extractant and / or the non-urea extractant, alone or in combination, is adjusted by combining the extractant(s) with a diluent while mixing at about 20°C to about 50°C, about 30°C to about 50°C, or any individual value or sub-range within these ranges, to form one or more reagent having a low viscosity of about 0.1 cP to about 15 cP, or any individual value or sub-range within this range.

[0049] In one or more embodiments, the urea extractant and the non-urea extractant are combined to form an extractant mixture. Each extractant or the extractant mixture may be combined with a modifier while mixing at about 20°C to about 50°C, about 30°C to about 50°C, or any individual value or sub-range within these ranges, to form the reagent composition. A diluent may or may not be present and / or combined with the urea extractant, the non-urea extractant and / or the mixture of the extractants with the modifier. As discussed above, the urea extractant and the non-urea extractant may be combined with the modifier over a range of suitable concentrations and ratios to form the reagent composition. The viscosity of the resulting reagent composition may be about 0. 1 cP to about 100 cP, or any individual value or sub-range within this range.Methods of Use

[0050] Further described herein are methods of using the inventive reagent compositions. Reagent compositions according to embodiments herein are suitable for use in a liquid-liquid solvent extraction process. In such solvent extraction processes, an aqueous feed solution (e.g., a lithium-containing brine) enters the system and is contacted with an organic solution. In various embodiments, a large organic to aqueous ratio may be needed to extract a target metal, compound thereof, salt thereof, or combinations thereof (e.g., lithium, lithium salt, lithium chloride, etc.) as the molar ratio of the extractant to the target metal may be 1 : 1.

[0051] The aqueous solution may be a metal-containing brine (e.g., a lithium-containing brine), brine from a salar, product stream from a pond evaporation process, product stream from a processing plant, or combinations thereof. In one or more embodiments, the aqueous feedsolution contains lithium, magnesium, calcium, boron, potassium, sodium, or combinations thereof. In embodiments, the aqueous feed solution comprises a lithium salt, magnesium salt, calcium salt, boron salt, potassium salt, sodium salt, or combinations thereof. In various embodiments, the aqueous feed solution comprises lithium or a lithium salt. The one or more target metals, compounds thereof, salts thereof, or combinations for extraction using the described methods may be lithium chloride, lithium sulfate, lithium hydroxide, lithium nitrate, or combinations thereof. According to various embodiments, the aqueous solution is a brine containing greater than about 60,000 ppm of magnesium, compounds thereof, salts thereof, or combinations thereof, and at least about 150 ppm of lithium, compounds thereof, salts thereof, or combinations thereof.

[0052] According to one or more embodiments, the aqueous solution may be contacted with a magnesium selective reagent composition, a calcium selective reagent composition, a boron selective reagent composition, or combinations thereof, prior to contacting the aqueous solution with the reagent composition to extract the one or more metals. Removing magnesium, calcium, and / or boron metals, compounds thereof, salts thereof, or combinations thereof, may improve the selectivity of a downstream lithium, compounds thereof, salts thereof, or combinations thereof solvent extraction process.

[0053] According to embodiments herein, the inventive reagent compositions may be combined with an organic solvent (e.g., a kerosene) to form the organic solution. The at least one urea extractant and the at least one non-urea extractant in the reagent composition are suitable to selectively extract one or more target metals including compounds thereof, salts thereof, or combinations thereof from the aqueous solution into the organic solution. In various embodiments, adding one or more reagent composition to the organic solution increases the extraction efficiency, selectivity and / or extraction rate for one or more target metal including compounds thereof, salts thereof, and / or combinations thereof. The metal depleted aqueous solution may be recycled to the combine with the aqueous feed solution and / or sent to another process for purification or removal of one or more additional metal, compounds thereof, salts thereof, or combinations thereof using solvent extraction and / or another metal removal process. The metal rich organic phase may be sent to one or more downstream processes (e.g., stripping, electro winning, etc.) to recover the one or more target metals that have been extracted from the aqueous solution.

[0054] In one or more embodiments, the methods include stripping the one or more metals from the metal rich organic phase. The stripping of the reagent can be accomplished with water. Following stripping, the metal depleted organic solvent may be returned to the solventextraction process for further contact with incoming aqueous feed. The metal depleted organic solvent is replenished with fresh reagent composition to ensure efficiency of the continuous process. In some embodiments, the concentration of lithium salt (e.g., lithium chloride) can be increased to at least 20,000 ppm at which point the stripping efficiency drops below 90%. This does not limit the concentration of the strip solution but may alter the amount of extractant necessary to keep extraction efficiency in an effective range. According to various embodiments, about 70% to about 99%, or at least about 95%, or any individual value or subrange within these ranges of the one or more metals is stripped from the metal rich organic phase.

[0055] According to various embodiments, further described herein are methods of extracting one or more metals comprising compounds thereof, salts thereof, or combinations thereof from an aqueous solution. The methods include contacting the aqueous solution with the reagent composition as described herein. As discussed above, the reagent composition may be contained in an organic solvent to form an organic solution. Upon contact between the aqueous solution and the organic solution containing at least one urea extractant and at least one nonurea extractant, the method further include extracting the one or more metals, compounds thereof, salts thereof, or combinations thereof from the aqueous solution into the organic solution containing the reagent composition until reaching equilibrium to form a metal depleted aqueous phase and a metal rich organic phase. In further embodiments, the methods include separating the metal depleted aqueous phase from the metal compound rich organic phase.

[0056] According to various embodiments, the methods may further include contacting the metal depleted aqueous phase with fresh reagent composition and further extracting the one or more metals, compounds thereof, salts thereof, or combinations thereof, from the aqueous solution into the metal rich organic phase (or fresh organic solution) until reaching equilibrium. This process may be repeated to further extract more target metal(s) from the aqueous phase using fresh reagent composition until the metal compound depleted aqueous phase is free or substantially free of the one or more target metals, compounds thereof, salts thereof, or combinations thereof.

[0057] In some embodiments, the methods further include emulsifying the metal rich organic phase. Emulsifying the organic phase can increase the surface area of the extractants to provide more bonding sites for the urea extractant and / or non-urea extractant to bond with the one or more target metals, compounds thereof, salts thereof, or combinations thereof.

[0058] The above methods may provide an overall extraction of the one or more metals, compounds thereof, salts thereof, or combinations thereof, from the aqueous solution of greaterthan about 70%, greater than about 80%, greater than about 90%, greater than about 92%, or about 70% to about 99%, or about 80% to about 93%, or any individual value or sub-range within these ranges. According to one or more embodiments, selectivity for the inventive reagent compositions is very high for lithium over sodium, potassium, magnesium, calcium, boron, and sulfate. In some embodiments, emulsions may be controlled to keep selectivity high, which may be addressed by controlling viscosity of the organic. Selection of suitable equipment maintain low entrainment mixing also may assist in emulsion control. In various embodiments, the target metal is lithium, lithium-containing compounds, lithium salts, or combinations thereof, and the selectivity of the urea extractant, the non-urea extractant, or a mixture thereof for lithium over magnesium is about 1 to about 50, about 5 to about 30, or about 10 to about 25.ILL USTRATIVE EXAMPLESExample 1 - Performance of lithium extraction of a brine using an amide extractant El of Formula (III) spiked with a urea extractant E2 and / or E3 of Formula (I) in a tributyl phosphate modifier (Ml)

[0054] Amide extractant El of Formula (III) was spiked with either a urea extractant E2 of Formula (I) or a urea extractant E3 of Formula (I) in a mixture with a tributyl phosphate modifier Ml . Varying ratios of amide extractant El to urea extractant E2 or E3 were evaluated. The extraction tests were conducted at an O: A of 5: 1 for one (1) hour at room temperature. Strip tests were conducted after each extraction stage at an O: A of 1: 1 using deionized (DI) water for one (1) hour at about 50°C. Both extraction and strip experiments were conducted using a shaker at a low setting. Nuclear magnetic resonance (NMR) imaging was used to measure Li and Na values in aqueous samples, while inductively coupled plasma (ICP) mass spectrometry was used to measure other elements in the strip solutions. Table 1 shows the composition of the feed solution.Table 1 - Composition of feed solution

[0055] Table 2 shows the extraction and strip results for the various extractant formulations.Table 2 - Summary of extraction and strip tests for urea spiked amide extractants in a modifier

[0056] This experiment demonstrated methods to optimize the performance of organic extractants in high Mg brines. The bolded extraction efficiencies in Table 2 were the highest values with a corresponding high selectivity for magnesium. Formulations having a relatively small amount of urea extractant added to the amide extractant provided good performance. A difference in extraction efficiency (as a loading factor) of 10% extraction can impact the stages and overall organic reagent necessary to achieve a low lithium raffinate. The presence of the urea extractant E2 or E3 in solution with amide extractant El can yield a high extraction performance seen with only urea (or amide without modifier), but unexpectedly enhanced the selectivity compared to either El, E2, E3 on their own. The urea-spiked amide extractant El improved the LiCl extraction performance by up to 40% and improved the Li / Mg selectivity by up to 180% as compared to an amide extractant El on its own. Lower amounts of extractants can be used with this formulations, which would further reduce the cost of the reagent. With a higher selectivity (Li / Mg mass ratio of 8-9), the LiCl product stream is of higher purity, which requires less Mg polishing for LiCl conversion.Example 2 - Performance of urea extractant E2 spiked with amide extractant El

[0057] A urea extractant E2 was spiked with amide extractant El. Different El :E2 ratios were evaluated. The extraction tests were conducted at an 0: A of 5: 1 for one (1) hour at room temperature. Strip tests were conducted after each extraction stage at O:A of 1: 1 using DI water for one (1) hour at about 50°C. Both extraction and strip experiments were performedusing a shaker at a low setting. NMR was used to measure Li and Na values in aqueous samples, while ICP was used to measure other elements in strip solutions.

[0058] Table 3 shows the composition of the feed solution.Table 3 - Composition of feed solution

[0059] The composition of the formulations contains the extractants and the residual volume is modifier. Table 4 shows the extraction and strip performance results for the extractant combinations.Table 4 - Summary of extraction and strip tests for urea spiked amide extractants in a modifier at varying ratios

[0060] Good conditions for extraction and the composition of the product were when there was an equi-volume mixture of each extractant El, E2 and the formulation was 50% modifier Ml. There was 74% extraction with a high selectivity for all ions. The ratio of Li / Mg in the product was about 8: 1, but this was unexpected because the starting ratio of Mg / Li was about 6: 1 giving an overall selectivity of almost 50 for Li over Mg. This experiment shows that a vanety of formulations are suitable depending on the needs of a lithium extraction plant including selectivity and / or extraction / stripping efficiency. In the case where the amide was higher in concentration, the selectivity was slightly lower while the extraction and stripping efficiency remained high.

[0061] This work shows that urea extractant E2 spiked amide extractant El performed better than amide extractant El spiked urea extractant E2 in terms of elective performance. The extraction performance for both was comparable. Nonetheless, the combination of these two extractants provides synergistic results under certain conditions.Example 3 - Performance of spiked amide / urea system (E1 / E2)

[0059] Solvent extraction was conducted using extractant solutions containing extractant El, extractant E2 and modifier Ml together with amide extractant E15 or E17 of Formula (III) or urea extractant E16 of Formula (II) as the organic phase. Extraction tests were conducted at an O:A of 5: 1 at room temperature using a shaker at a low setting. Strip tests were conducted using DI water at an O:A of 1: 1 at about 50°C. NMR was used to measure Li values in aqueous samples, while ICP was used to measure other elements in strip solutions.

[0060] Table 5 shows the composition of the feed solution for the various extraction reactions.Table 5 - Composition of feed solution

[0061] Table 6 shows the extraction test results for various mixtures of extractants and modifiers.Table 6 - Summary of extraction and strip test results using a spiked amide / urea extractant

[0062] The mixture of an amide extractant and a urea extractant showed a synergistic extraction effect. The extraction of lithium was improved when using the mixture than for either of the individual extractants. The spiking of a third extractant continued this trend of remaining a good extractant formulation with very good selectivity.Example 4 - Performance of a urea extractant spiked with an amide extractant

[0063] Solvent extraction experiments were conducted using a mixture of a urea extractant E3 and / or E16 with an amide extractant E18 or E19 of Formula (III). Extraction tests were conducted at an O:A of 5:1 for one (1) hour at room temperature. Strip tests were conducted at an 0: A of 1 : 1 using DI water for one (1) hour at about 50°C. All experiments were performed using a shaker at a low setting. NMR was used to measure Li and Na values in aqueous samples, while ICP was used to measure other elements in strip solutions.

[0064] Table 7 shows the composition of the feed solution for the various extraction reactions.Table 7 - Composition of feed solution

[0065] Table 8 shows the solvent extraction results when employing various mixtures of extractants and modifiers in the organic phase.Table 8 - Summary of extraction and strip test results using a urea extractant spiked with an amide extractant

[0066] These results demonstrated that an effective combination of amine and urea extractants used in solvent extraction, contained isomers or extractants in combination that have slightly different alkyl chains. If the isotherms were not substantially different for each component, the mixtures were very effective. Without being bound by any particular theory, it is believed that the reason for these results is that solutions that are more homogeneous do not solubilize complexes as well. Additionally, there is anecdotal evidence that if one species is kinetically faster than the others it does a lot of the extraction and then the ions are exchanged with the species that are more thermodynamically favored. This works more like an assembly line whereinterfacial extraction is accomplished with one species and complexation to higher net transfer with another.

[0067] This work shows that improved performance can also be achieved by spiking a urea extractant with a different urea-based extractant. Reagents containing a combination of two different urea extractants or urea / amide extractants showed higher performance than the nonspiked urea or amide.

[0068] The foregoing description discloses example embodiments of the disclosure. Modifications of the above-disclosed assemblies, apparatus, and methods which fall within the scope of the disclosure will be readily apparent to those of ordinary skill in the art. Accordingly, while the present disclosure has been disclosed in connection with example embodiments, it should be understood that other embodiments may fall within the scope of the disclosure, as defined by the following claims.

[0069] Although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

CLAIMSWhat is claimed is:

1. A reagent composition, comprising: at least one urea extractant capable of selectively extracting one or more metals, compounds thereof, salts thereof, or combinations thereof, from an aqueous solution; and at least one non-urea extractant capable of selectively extracting one or more metals, compounds thereof, salts thereof, or combinations thereof, from the aqueous solution.

2. The reagent composition of claim 1, wherein the one or more metals comprise lithium, magnesium, calcium, boron, potassium, sodium, or combinations thereof.

3. The reagent composition of claim 1 or 2, wherein the one or more metals comprise a lithium salt, magnesium salt, calcium salt, boron salt, potassium salt, sodium salt or combinations thereof.

4. The reagent composition of any preceding claim, wherein the one or more metals comprise lithium or a lithium salt.

5. The reagent composition of any preceding claim, wherein the at least one urea extractant comprises one or more urea compound chosen from the following Formula (I), Formula (II), or combinations thereof:wherein R1, R2, R3and R4is each independently hydrogen, a methyl group, an ethyl group, a straight or branched C3-C20 alkyl group, a C3-C12 cycloalkyl group having a single ring structure, a C6-C10 aromatic ring group, a C3-C20 alkylphenyl group, a straight or branchedC3-C20 alkenyl group, a straight or branched C3-C20 alkynyl group, a thiol group, wherein each of the C3-C20 alkyl, alkenyl or alkynyl groups may be interrupted with N, 0 or S.

6. The reagent composition of any preceding claim, wherein the at least one non-urea extractant comprises an amide compound chosen from the following Formula (III), Formula (IV), Formula (V), or combinations thereof:wherein R5, R6, R7, R8, R9, R10, R11, R13, R14and R15is each independently hydrogen, a methyl group, an ethyl group, a straight or branched C3-C20 alkyl group, a C3-C12 cycloalkyl group having a single ring structure, a Ce-Cio aromatic ring group, a C1-C20 alkylphenyl group, a dihydrobenzodioxene group, a straight or branched C1-C20 alkanol group, a straight or branched C1-C20 alkyldiol group, a straight or branched C3-C20 alkenyl group, a straight or branched C3-C20 alkynyl group, a thiol group, wherein at least one carbon atom of R5, R6, R7, R8, R9, R10, R11, R13, R14and R15may be substituted with a N, 0 or S, and wherein R12is a bond, a methyl group, an ethyl group, a straight or branched C3-C20 alkyl group, a C3-C12 cycloalkyl group having a single ring structure, a Ce-Cio aromatic ring group, a C3-C20 alkylphenyl group, a straight or branched C3-C20 alkenyl group, a straight or branched C3-C20 alkynyl group, a thiol group, wherein at least one carbon atom of R12may be substituted with N, 0 or S.

7. The reagent composition of any preceding claim, further comprising an alcohol, an organophosphorous solvent, or a combination thereof.

8. The reagent composition of any preceding claim, further comprising at least one modifier, wherein the at least one modifier comprises one or more functional group having a dipole moment and / or that is attached to a highly polar ionic bond.

9. The reagent composition of any preceding claim, further comprising at least one modifier, wherein the at least one modifier comprises an aliphatic component that is attracted to non-polar moieties of the at least one urea extractant.

10. The reagent composition of any preceding claim, comprising the at least one modifier, wherein the at least one modifier comprises one or more functional group chosen from a diether, amide, imide, ketone, alcohol, ether, alkyl phosphine, phosphate, ester, phosphonic acid, phosphonic acid, phosphoric acid and / or nitrile.

11. The reagent composition of any preceding claim, further comprising: at least one modifier, wherein the at least one modifier is chosen from 1,6-di-t-butoxy hexane, di(ethylene glycol) dibutyl ether, 1,4-bis-t-butoxy butane, 2-ethylhexyl succinimide, 4-t-butylcyclohexanone, l-butyl-3-methylimidazolium methyl sulfate, iminodiacetic acid (IDA), dodecanol, 2,2,4-trimethyl-l,3-pentanediol diisobutyrate (TXIB), ethyoxylated isotridecyl phosphate (TDA), cy decanol, l-methyl-3-octylimidazolium chloride, trihexyltetradecylphosphomum chloride, l-decyl-3-methylimidazolium tetrafluoroborate, 7- ethyl-2-methyl-undecanol, hexyl 3-methylimidazolium chloride, tnmethyl nonanol, 4- isopropyl cyclohexanone, t-butyl octyl ether, 3-isopropyl cyclohexanone, 3,3,5-trimethyl cyclohexanone, methyl n-propyl ketone (e.g., Eastman Cn ketone), 5-ethyl-2-nonanone, a mixture of phosphine oxides (e.g., Cyanex 923), tributyl phosphate, 6-undecanone, heptyl 2- ethylbutyrate, 2-ethylbutyl caproate, 3-(cyclohexyl)-propionitrile, di(2-ethylhexyl)phthalate, tris(2-ethylhexyl)phosphate, triisobutyl phosphate, ethyl acetate, or a combination of any two or more thereof; and / or at least one diluent, wherein the at least one diluent comprises, octanol, trideconal, 2- ethy 1-1 -hexanol, 3-methyl-l -butanol, isoamyl alcohol, 2-hexyl decanol, octanoic acid, trioctylphosphine oxide (e.g., Cyanex® 923), petroleum distillates solvent (e.g., Orform® SX80), aromatic C9-C10 solvent (e.g., Shellsol® A150), a kerosene (e.g., Orform® SX11), dibutyl carbitol, dichloromethane, trioctylmethylammonium chloride (e.g., Aliquat 336), chloroform, or a combination of any two or more thereof.

12. The reagent composition of any preceding claim, comprising the at least one urea extractant in an amount of greater than 0 wt%, or about 1 wt% to about 99 wt%, based on the total weight of the reagent composition.

13. The reagent composition of any preceding claim, comprising the at least one non-urea extractant in an amount of greater than 0 wt%, or about 1 wt% to about 99 wt%, based on the total weight of the reagent composition.

14. The reagent composition of any preceding claim, comprising at least one modifier and / or diluent in an amount of greater than 0 v .%, or about 1 wt% to about 99 wt%, based on the total weight of the reagent composition.

15. The reagent composition of any preceding claim, wherein a weight ratio of the at least one urea extractant to the at least one non-urea extractant is about 1 : 10 to about 100: 1.

16. The reagent composition of any preceding claim, comprising at least one modifier and / or diluent, wherein a weight ratio of the at least one urea extractant to the at least one modifier and / or diluent is about 1: 10 to about 100: 1.

17. A method of extracting one or more metals, compounds thereof, salts thereof, or combinations thereof from an aqueous solution, comprising: contacting the aqueous solution with an organic solution comprising the reagent composition of any preceding claim; and extracting the one or more metals, compounds thereof, salts thereof, or combinations thereof from the aqueous solution into the organic solution until reaching equilibrium to form a metal depleted aqueous phase and a lithium salt rich organic phase.

18. The method of claim 17, wherein the aqueous solution is a metal-containing brine, brine from a salar, product stream from a pond evaporation process, product stream from a processing plant, or combinations thereof, optionally, wherein the aqueous solution is contacted with a magnesium selective reagent composition, a calcium selective reagent composition, a boron selective reagent composition, or combinations thereof, prior to contacting the aqueous solution with the reagent composition to extract the one or more lithium salts.

19. The method of claim 17 or 18, wherein the one or more lithium salts comprised in the aqueous solution comprise lithium chloride, lithium sulfate, lithium hydroxide, lithium nitrate or combinations thereof.

20. The method of any one of claims 17 to 19, further comprising contacting the metal depleted aqueous phase with organic solution comprising fresh reagent composition and further extracting the one or more metals, compounds thereof, salts thereof, or combinations thereof from the aqueous solution into the metal rich organic phase until reaching equilibrium, and optionally repeating the further extracting with the organic solution comprising the fresh reagent composition until the metal depleted aqueous phase is free or substantially free of the one or more metals, compounds thereof, salts thereof, or combinations thereof.

21. The method of any one of claims 17 to 20, further comprising emulsifying the metal rich organic phase.

22. The method of any one of claims 17 to 21, further comprising separating the metal depleted aqueous phase from the metal rich organic phase.

23. The method of any one of claims 17 to 22, further comprising stripping the lithium from the metal rich organic phase, optionally, wherein about 70% to about 99%, or about 95% of the lithium is stripped from the metal rich organic phase.

24. The method of any one of claims 17 to 23, wherein the overall extraction of lithium from the aqueous solution is greater than about 70%, greater than about 80%, greater than about 90%, greater than about 92%, or about 70% to about 99%, or about 80% to about 93.

25. The method of any one of claims 17 to 24, wherein the selectivity of lithium over magnesium is about 1 to about 50, about 5 to about 30, or about 10 to about 25.

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