Process and system

Abstract

System and a process for brine treatment in a direct lithium extraction (DLE) process. The system and process involve brine pre-treatment to remove target impurities in the brine that can be transferred to the final product and / or chemically damage the sorbent in the DLE process.

Description

[0001] PROCESS AND SYSTEM

[0002] TECHNICAL FIELD

[0003]

[0001] This invention relates to a process and a system for removal of target impurities from lithium brines. The process and system particularly relate to the removal of target impurities from lithium brines prior to and / or during a direct lithium extraction process. This invention also relates to processes to selectively remove impurities in lithium brines by an adsorption mechanism.

[0004] BACKGROUND ART

[0005]

[0002] Lithium is present naturally in many rocks (such as pegmatites), ocean water, brines, mineral springs and ground waters. Lithium solutions can also be a side product from lithium processing facilities, battery recycling plants, oil well brines, formation waters, produce waters, or other waste streams. However, these sources may only contain low concentrations of lithium, for example sea water contains less than 1 mg / L of lithium. Therefore, to be extracted for use, the lithium must be concentrated and / or converted into a useful chemical form.

[0006]

[0003] Direct Lithium Extraction (DLE) is a technology used to efficiently and selectively extract lithium from solutions with low concentrations of lithium such as geothermal, oilfield and continental fluids. Unlike traditional methods like evaporation ponds or conventional mining, DLE utilizes advanced techniques like adsorption, ion exchange, and membrane processes to selectively extract lithium.

[0007]

[0004] Lithium has many uses, but one of the most dominant is the manufacture of batteries, which has high demand due to the growing use of electronics, electric vehicles and storage of renewable energy such as solar power.

[0008]

[0005] Lithium can be extracted from solution (for example brines) using a sorbent. For example, JPS61247618A describes a method for recovering lithium from geothermal hot water using a lithium manganese oxide sorbent.

[0009]

[0006] Transitional metal oxides (such as lithium manganese oxides and lithium titanium oxides) are examples of sorbent materials that can be applied in the DLE process due to their efficient lithium extraction / insertion reactions. These materials are promising for use as selective adsorbents in low to medium lithium-bearing brines. They have also been studied for the development of cathode materials for rechargeable batteries.

[0010]

[0007] US 10,332,950 B2 describes a lithium sorbent, a method for producing the same, and a method for recovering lithium from a dilute solution using the same.

[0011]

[0008] In this specification, where reference has been made to external sources of information, including patent specifications and other documents, this is generally for the purpose of providing a context for discussing the features of the present invention. Unless stated otherwise, reference to such sources of information is not to be construed, in any jurisdiction, as an admission that such sources of information are prior art or form part of the common general knowledge in the art.

[0012] SUMMARY OF THE INVENTION

[0013]

[0009] It is an object of this disclosure to provide a system and a process for removing impurities from lithium brines to prevent their retention / accumulation within the lithium extraction process and / or sorbent degradation which goes at least some way towards overcoming one or more of the abovementioned problems or difficulties, and / or to at least provide the public with a useful choice.

[0014]

[0010] In a first aspect, the invention provides a process for extracting lithium from an aqueous solution containing lithium, the process comprising:

[0015] (i) contacting the aqueous solution containing lithium with an adsorption media to produce a treated aqueous solution and a loaded adsorption media, and separating the treated aqueous solution and the loaded adsorption media,

[0016] (ii) contacting the treated aqueous solution with a lithium sorbent to produce a lithium loaded sorbent and lithium depleted solution,

[0017] (iii) separating the lithium loaded sorbent and the lithium depleted solution,

[0018] (iv) treating the lithium loaded sorbent to produce a mixture of a lithium rich solution and a regenerated sorbent, and

[0019] (v) separating the lithium rich solution and the regenerated sorbent; wherein step (i) reduces the concentration of an impurity in the aqueous solution containing lithium and wherein the impurity comprises a reducing agent, a transition metal, an alkaline- earth metal, a post-transition metal, an inorganic additive, an impurity with a molecular weight above about 50 kilo-Daltons (kDa), an impurity with a hydration radius greater than about 0.01 pm, or a combination of any two or more thereof.

[0020]

[0011] In a second aspect, the invention provides a process for extracting lithium from an aqueous solution containing lithium, the process comprising:

[0021] (i) contacting the aqueous solution containing lithium with an adsorption media to produce a treated aqueous solution,

[0022] (ii) extracting lithium from the treated aqueous solution with a direct lithium extraction, wherein step (i) reduces the concentration of an impurity in the aqueous solution containing lithium and wherein the impurity comprises a reducing agent, a transition metal, an alkaline- earth metal, a post-transition metal, an inorganic additive, an impurity with a molecular weight limit above 50 kDa, an impurity with a hydration radius greater than about 0.01 pm, or a combination of any two or more thereof.

[0023]

[0012] In a third aspect, the invention provides a process for extracting lithium from an aqueous solution containing lithium the process comprising:

[0024] (i) contacting the aqueous solution containing lithium with an adsorption media to produce a treated aqueous solution;

[0025] (ii) extracting lithium from the treated solution with a direct lithium extraction; wherein step (i) reduces the concentration of an impurity in the aqueous solution containing lithium and wherein the impurity comprises a reducing agent, a transition metal, an alkaline- earth metal, a post-transition metal, an inorganic additive, an impurity with a molecular weight above 50 kDa, an impurity with a hydration radius greater than about 0.01 pm, or a combination of any two or more thereof; and wherein (a) the performance of the lithium sorbent is improved, (b) contamination of the lithium rich solution is reduced, and / or (c) process equipment clogging and / or fouling is reduced compared to a direct lithium extraction process without step (i).

[0013] In a fourth aspect, the invention provides a system for extracting lithium from an aqueous solution containing lithium, the system comprising:

[0026] (i) a first container for contacting the aqueous solution containing lithium with an adsorption media to reduce the concentration of an impurity in the aqueous solution, wherein the first container comprises (a) an absorption bed or column comprising the adsorption media, and / or (b) a filtration system utilising a pore size of less than 0.02 pm or a molecular weight cut-off of 50 kDa or smaller,

[0027] (ii) a second container for contacting the treated aqueous solution with a lithium sorbent to produce a lithium loaded sorbent and lithium depleted solution,

[0028] (iii) a first separating device to separate the lithium loaded sorbent and the lithium depleted solution,

[0029] (iv) means for treating the lithium loaded sorbent to produce a mixture of a lithium rich solution and a regenerated sorbent, and

[0030] (v) a second separating device to separate the lithium rich solution and the regenerated sorbent.

[0031]

[0014] Any of the aforementioned features or embodiments or aspects may be combined with one or more of the other features or embodiments or aspects as described herein.

[0032]

[0015] In some embodiments, the adsorption media is a metal oxide. In some embodiments, the metal oxide is iron oxide or manganese oxide. In some embodiments, the metal oxide is provided on a substrate, e.g., a carbon-based substrate or a silica-based substrate (e.g. sand, zeolite). In some embodiments the adsorption media is activated carbon. In some embodiments the adsorption media is a polymeric resin. In some embodiments, the adsorption media comprises a by-product of the process. In some embodiments, the byproduct is a calcined by-product such as an oxide. In some embodiments, the by-product of the process is manganese carbonate, manganese hydroxide, manganese oxide or a combination of any two or more thereof. In some embodiments, the adsorption media is provided in a packed column. In some embodiments, the packed column comprises a metal oxide (such as iron oxide or manganese oxide). In some embodiments, the adsorption media is provided in an adsorption bed. In some embodiments, the absorption media is a loose powder.

[0016] In some embodiments, the first container is a packed column containing the adsorption media. In some embodiments, the packed column comprises a metal oxide (e.g. an iron oxide or a manganese oxide) on a substrate (e.g. a carbon-based substrate or a silica- based substrate).

[0033]

[0017] In some embodiments the contacting in step (i) is performed under constant agitation in a stirred tank, pumped into a column or by recirculation.

[0034]

[0018] In some embodiments the impurities are removed by an adsorption mechanism (e.g. chemisorption or physisorption).

[0035]

[0019] In some embodiments, the impurity comprises a reducing agent, a transition metal, an inorganic additive and a combination of any two or more thereof.

[0036]

[0020] In some embodiments, the impurity comprises a reducing agent. In some embodiments, the reducing agent is H2S. In some embodiments, the impurity comprises a transition metal. In some embodiments, the transition metal is Fe, Mn or a combination thereof. In some embodiments, the impurity comprises an alkaline-earth metal. In some embodiments, the alkaline-earth metal is Be, Mg, Ca, Sr, Ba, Ra or a combination of any two or more thereof. In some embodiments, the impurity comprises a post-transition metal. In some embodiments, the post-transition metal is Al, Ga, In, Sn, Tl, Pb, Bi or a combination of any two or more thereof. In some embodiments, the impurity comprises an inorganic additive. In some embodiments the inorganic additive is a flocculant. In some embodiments, the flocculant is aluminum sulfate, aluminum chloride, calcium sulphate, ferric chloride or a combination of any two or more thereof. In some embodiments, the impurity comprises a radioactive material. In some embodiments, the radioactive material comprises a natural occurring radioactive material (NORM) and / or a technologically enhanced naturally occurring radioactive material (TENORM). In some embodiments, the radioactive material is Ra-226, Ra-228, Pb-210, Sr-90 or a combination of any two or more thereof. In some embodiments, the impurity comprises a molecular weight of above 50 kDa.

[0037]

[0021] In some embodiments, the temperature of the aqueous solution before and during the contacting in step (i) is 0 °C to 100 °C.

[0038]

[0022] In some embodiments, the aqueous solution is processed in a flash tank, air sparged, nitrogen sparged, placed under vacuum or put through a tortoise path prior to step (i) to lower the pressure of the aqueous solution, and / or to lower the temperature of the aqueous solution, and / or to lower the concentration of gases. In some embodiments, the aqueous solution is processed in a flash tank, air sparged, nitrogen sparged, placed under vacuum or put through a tortoise path prior to step (i) to lower the concentration of a gas selected from CO2, H2S, CH4, volatile organic carbon, or a mixture of any two or more thereof. In some embodiments, the aqueous solution is processed in a flash tank prior to step (i) to lower the pressure of the aqueous solution, and / or to lower the temperature of the aqueous solution, and / or to lower the concentration of gases. In some embodiments, the aqueous solution is processed in a flash tank prior to step (i) to lower the concentration of a gas selected from CO2, H2S, CH4, volatile organic carbon, or a mixture of any two or more thereof.

[0039]

[0023] In some embodiments, the concentration of the impurity is reduced in step (i) to below about 10 mg / L. In some embodiments, the concentration of impurity is reduced in step (i) to below about 5 mg / L. In some embodiments, the concentration of the impurity is reduced in step (i) to below about 1 mg / L.

[0040]

[0024] In some embodiments, the impurity comprises a combination of any two or more of a reducing agent, a transition metal, an alkaline-earth metal, a post-transition metal, an inorganic additive, an impurity with a molecular weight above about 50 kilo-Daltons (kDa) and an impurity with a hydration radius greater than about 0.01 pm. In some embodiments, the impurity comprises a combination of any three or more of a reducing agent, a transition metal, an alkaline-earth metal, a post-transition metal, an inorganic additive, an impurity with a molecular weight above about 50 kilo-Daltons (kDa) and an impurity with a hydration radius greater than about 0.01 pm. In some embodiments, the impurity comprises a combination of any four or more of a reducing agent, a transition metal, an alkaline-earth metal, a post-transition metal, an inorganic additive, an impurity with a molecular weight above about 50 kilo-Daltons (kDa) and an impurity with a hydration radius greater than about 0.01 pm. In some embodiments, the impurity comprises a combination of any two or more of a reducing agent, a transition metal and an inorganic additive.

[0041]

[0025] In some embodiments, the impurity comprises a combination of two or more of H2S, Fe, Mn and Zn. In some embodiments, the impurity is a combination of two or more of H2S, Fe, Mn and an inorganic additive is reduced in step (i). In some embodiments, the impurity comprises a combination of H2S, Fe, Mn and Zn. In some embodiments, the impurity comprises a combination of H2S, Fe, Mn and an inorganic additive (e.g. aluminum sulfate, aluminum chloride, calcium sulphate, ferric chloride or a combination of any two or more thereof). In some embodiments, the impurity comprises a combination of two or more of H2S, Fe, Mn, Pb, Ra, Sr and Zn. In some embodiments, the impurity comprises a combination of two or more H2S, Fe, Mn, Pb, Ra, Sr, Zn and an impurity with a molecular weight of above 50 kDa. In some embodiments, the impurity comprises a combination of three or more of H2S, Fe, Mn, Pb, Ra, Sr, Zn and an impurity with a molecular weight of above 50 kDa. In some embodiments, the impurity comprises a combination of four or more of H2S, Fe, Mn, Pb, Ra, Sr, Zn and any species with a molecular weight of above 50 kDa. In some embodiments, the impurity comprises a combination of five or more of H2S, Fe, Mn, Pb, Ra, Sr, Zn and an impurity with a molecular weight of above 50 kDa.

[0042]

[0026] In some embodiments, when the impurity comprises a combination of impurities, the concentration of each impurity is reduced concurrently or sequentially in step (i).

[0043]

[0027] In some embodiments, the concentration of at least two impurities selected from the group consisting of H2S, Fe and Mn is reduced in step (i). In some embodiments, the concentration of at least two impurities selected from the group consisting of H2S, Fe, Mn and an inorganic additive is reduced in step (i). In some embodiments, the concentration of H2S, Fe and Mn is reduced in step (i). In some embodiments, the concentration of H2S, Fe, Mn and an inorganic additive (e.g. aluminum sulfate, aluminum chloride, calcium sulphate, ferric chloride or a combination of any two or more thereof) is reduced in step (i). In some embodiments, the concentration of at least two impurities selected from the group consisting of H2S, Fe, Mn, Pb, Ra, Sr, and Zn is reduced in step (i). In some embodiments, the concentration of at least two impurities selected from the group consisting of H2S, Fe, Mn, Pb, Ra, Sr, Zn and an impurity with a molecular weight of above 50 kDa is reduced in step (i). In some embodiments, the concentration of at least three impurities selected from the group consisting of H2S, Fe, Mn, Pb, Ra, Sr, Zn and an impurity with a molecular weight of above about 50 kDa is reduced in step (i). In some embodiments, the concentration of at least four impurities selected from the group consisting of H2S, Fe, Mn, Pb, Ra, Sr, Zn and any species with a molecular weight of above 50 kDa is reduced in step (i). In some embodiments, the concentration of at least five impurities selected from the group consisting of H2S, Fe, Mn, Pb, Ra, Sr, Zn and an impurity with a molecular weight of above about 50 kDa is reduced in step (i).

[0044]

[0028] In some embodiments, the treated aqueous solution obtained in step (i) has a H2S concentration below about 10 mg / L In some embodiments, the treated aqueous solution obtained in step (i) has a H2S concentration below about 1 mg / L In some embodiments, the treated aqueous solution obtained in step (i) has an Fe concentration below about 10 mg / L. In some embodiments, the treated aqueous solution obtained in step (i) has Fe concentration below about 1 mg / L. In some embodiments, the treated aqueous solution obtained in step (i) has a Mn concentration below about 10 mg / L. In some embodiments, the treated aqueous solution obtained in step (i) has a Mn concentration below about 1 mg / L. In some embodiments, the treated aqueous solution obtained in step (i) has an inorganic additive (e.g. aluminum sulfate, aluminum chloride, calcium sulphate, ferric chloride or a combination of any two or more thereof) concentration below about 10 mg / L. In some embodiments, the treated aqueous solution obtained in step (i) has an inorganic additive (e.g. aluminum sulfate, aluminum chloride, calcium sulphate, ferric chloride or a combination of any two or more thereof) concentration below about 1 mg / L. In some embodiments, the treated aqueous solution obtained in step (i) has an impurity with a molecular weight above 50 kDa concentration below about 10 mg / L. In some embodiments, the treated aqueous solution obtained in step (i) has an impurity with a molecular weight above 50 kDa concentration below about 1 mg / L.

[0045]

[0029] In some embodiments, step (i) comprises identifying the presence of the impurity in the aqueous solution comprising lithium and contacting the aqueous solution with the adsorption media to reduce the concentration of the impurity.

[0046]

[0030] In some embodiments, step (i) comprises monitoring the concentration of the impurity in the aqueous solution comprising lithium. In some embodiments, step (i) comprises monitoring the concentration of the impurity in the aqueous solution comprising lithium and contacting the aqueous solution with the adsorption media to reduce the concentration of the impurity below a predetermined level. In some embodiments, step (i) comprises monitoring the concentration of the impurity in the aqueous solution comprising lithium and contacting the aqueous solution with the adsorption media to reduce the concentration of the impurity below about 10 mg / l, preferably below about 1 mg / L.

[0031] In some embodiments, step (i) is monitored until the concentration of the impurity is reduced to below about 10 mg / L by ICP-OES. In some embodiments, step (i) is monitored until H2S is below about 10 mg / L by colorimetric analysis (Hach H2S test). In some embodiments, step (i) is monitored until the concentration of the impurity having a molecular weight below 50 kDa is below about 10 mg / L.

[0047]

[0032] In some embodiments, step (i) comprises identifying the presence of a reducing agent, a transition metal, an alkaline-earth metal, a post-transition metal, an inorganic additive, an impurity with a molecular weight above about 50 kilo-Daltons (kDa) and an impurity with a hydration radius greater than about 0.01 pm and, if present, reducing the concentration of each impurity. In some embodiments, step (i) comprises measuring the concentration of a reducing agent, a transition metal and an inorganic additive and, if present in a concentration above about 10 mg / L, reducing the concentration of each impurity to below about 10 mg / L, preferably below about 1 mg / L.

[0048]

[0033] In some embodiments, step (i) comprises measuring the concentration of H2S, Fe, Mn, and an inorganic additive (e.g. aluminum sulfate, aluminum chloride, calcium sulphate, ferric chloride or a combination of any two or more thereof), and if present in a concentration above about 10 mg / L, reducing the concentration of each impurity to below about 10 mg / L, preferably below about 1 mg / L. In some embodiments, step (i) comprises measuring the concentration of H2S, Fe and Mn, and if present in a concentration above about 10 mg / L, reducing the concentration of each impurity to below about 10 mg / L, preferably below about 1 mg / L.

[0049]

[0034] In some embodiments, the treated aqueous solution has a H2S concentration below about 10 mg / L (preferably below about 1 mg / L), an Fe concentration below about 10 mg / L (preferably below about 1 mg / L), a Mn concentration below about 10 mg / L (preferably below about 1 mg / L), an inorganic additive (e.g. aluminum sulfate, aluminum chloride, calcium sulphate, ferric chloride or a combination of any two or more thereof) concentration below about 10 mg / L (preferably below about 1 mg / L), wherein the concentration of at least one of H2S, Fe, Mn or the inorganic additive is reduced relative to the aqueous solution comprising lithium before step (i). In some embodiments, the treated aqueous solution has a H2S concentration below about 10 mg / L (preferably below about 1 mg / L), an Fe concentration below about 10 mg / L (preferably below about 1 mg / L) and a Mn concentration below about 10 mg / L (preferably below about 1 mg / L), wherein the concentration of at least one of H2S, Fe or Mn is reduced relative to the aqueous solution comprising lithium before step (i).

[0050]

[0035] In some embodiments, the impurity comprises an impurity with a molecular weight greater than about 120 kDa. In some embodiments, the impurity comprises an impurity with a molecular weight greater than about 80 kDa. In some embodiments, the impurity comprises an impurity with a molecular weight greater than about 50 kDa.

[0051]

[0036] In some embodiments, the impurity comprises an impurity with a hydration radius greater than about 30 nm. In some embodiments, the impurity comprises an impurity with a hydration radius greater than about 15 nm. In some embodiments, the impurity comprises an impurity with a hydration radius greater than about 8 nm.

[0052]

[0037] In some embodiments, the impurity has a particle size greater than 30 nm. In some embodiments, step (i) comprises treating the aqueous solution containing lithium with physical separation technique (e.g. ultrafiltration) to remove the impurity, wherein the impurity has a particle size greater than 30 nm.

[0053]

[0038] In some embodiments, the impurity has a particle size less than 30 nm. In some embodiments, step (i) comprises treating the aqueous solution containing lithium with an adsorption media to remove the impurity, wherein the impurity has a particle size less than 30 nm.

[0054]

[0039] In some embodiments, the first container comprises means for measuring a chemical composition of the aqueous solution. In some embodiments, the means to the chemical composition of the aqueous solution is colorimetric analysis Hach Mn test, ICP-OES, Flame AA or a combination of any two or more thereof. In some embodiments, the first container comprises means for measuring the amount of H2S in the aqueous solution. In some embodiments, the means for measuring the amount of H2S is colorimetric analysis Hach H2S test. In some embodiments, the first container comprises means for measuring the concentration of Mn in the aqueous solution, e.g., colorimetric analysis Hach Fe test, ICP- OES, Flame AA or a combination of any two or more thereof. In some embodiments, the first container comprises means for measuring the concentration of Fe in the aqueous solution, e.g., colorimetric analysis Hach Fe test, ICP-OES, Flame AA. In some embodiments, the first container comprises means for measuring the impurity with a molecular weight above 50 kDa, e.g., an ICP-OES analyzer, a Flame AA analyzer, laser diffraction analysis, dynamic light scattering, turbidity meter, Silt Density Index, or a combination of any two or more thereof.

[0055]

[0040] In some embodiments, the aqueous solution containing lithium is treated by contacting different absorption media for the removal of other impurities before, during and / or after step (i).

[0056]

[0041] In some embodiments, step (i) further comprises treating the aqueous solution comprising lithium with a physical separation technique. In some embodiments, the physical separation technique is microfiltration or ultrafiltration. In some embodiments, the physical separation technique may further comprise coagulation and flocculation, sedimentation, skimming, dissolved air flotation (DAF), coalescence, hydro cyclone separation or a combination of any two or more thereof. In some embodiments, the physical separation technique is ultrafiltration. In some embodiments, the ultrafiltration comprises the use of a hollow fiber membrane. In some embodiments, the ultrafiltration comprises a crossflow system.

[0057]

[0042] In some embodiments, the adsorption media is regenerated at the end of a service cycle for re-use in the process.

[0058]

[0043] In some embodiments, the adsorption media is alternated between on duty and off duty cycles, wherein on duty cycle means the media is in contact with the aqueous solution to actively remove contaminants and off duty cycle means the media is under regeneration, under maintenance or other operational process. In some embodiments, the adsorption media comprises at least two modules such that one module may be on duty cycle while the other is off duty cycle to facilitate a continuous operational process. In some embodiments, the adsorption media system comprises of a batch operational process. In some embodiments, the end of a service cycle of the adsorption media is determined when a capacity of the media to adsorb the impurity is below a predetermined value. In some embodiments, the end of a service cycle of the adsorption media is determined when a flow rate through the adsorption media declines below a predetermined value. In some embodiments, the end of a service cycle of the adsorption media is determined when a concentration of the impurity reaches a predetermined value.

[0044] In some embodiments, the adsorption media can be regenerated at the end of a service cycle. In some embodiments, the system further comprises a third container to regenerate the adsorption media. The adsorption media can be desorbed or regenerated by a number of methods, depending on the nature of the media and the impurity present. In some embodiments, the adsorption media is regenerated by treating the adsorption media with an aqueous acid, an aqueous base, an organic solvent, an oxidant, a solvent extraction, a complexing agent, a chelating agent, a reducing agent, steam or heat. In some embodiments, the adsorption media is not re-used in the process. In some embodiments, the adsorption media is backwashed to remove the impurity, e.g., in the filter bed. In some embodiments, the media regeneration comprises of a back wash process to remove the impurity from the adsorption media. In some embodiments, the impurities removed in step (i) are subsequently redissolved in or mixed with the lithium depleted solution. In some embodiments, the impurity and lithium depleted solution is reinjected underground. In some embodiments, the impurity is disposed of as a solid waste.

[0059]

[0045] In some embodiments, the system further comprises a fourth container for storing the impurity. In some embodiments, the system further comprises a fourth container for storing the impurity with the regenerant solution.

[0060]

[0046] In some embodiments, the system further comprises a fifth container for storage, disposal or reinjection underground of the lithium depleted solution. In some embodiments, the system further comprises a fifth container for storage, disposal or reinjection underground of the lithium depleted solution combined with the desorbed impurities from the adsorption media and regenerant.

[0061]

[0047] In some embodiments, the loaded adsorption media is recycled in the process. In some embodiments, the loaded adsorption media is recycled by repeating step (i) with the regenerated adsorption media and a further aqueous solution containing lithium. In some embodiments, the adsorption media is recycled at least 3 times. In some embodiments, the adsorption media is recycled at least 5, 10, 20, 50 or 100 times.

[0062]

[0048] In some embodiments, the adsorption media is recycled until its capacity is exhausted.

[0049] In some embodiments, when the adsorption media is recycled, the performance of the media is monitored until the impurity level reaches a maximum threshold.

[0063]

[0050] In some embodiments, the adsorption media is recycled in the process.

[0064]

[0051] In some embodiments, the lithium sorbent is a metal oxide-based ion exchange sorbent. In some embodiments, the metal oxide-based ion exchange sorbent is a hydrogen manganese oxide sorbent or hydrogen titanium oxide sorbent. In some embodiments, the metal oxide-based ion exchange sorbent is a hydrogen manganese oxide sorbent. In some embodiments, the sorbent is in a micronised form. In some embodiments, the sorbent has an average particle size of about 100 pm or less. In some embodiments, the sorbent has an average particle size of about 50 pm or less. In some embodiments, the sorbent has an average particle size of about 10 pm or less.

[0065]

[0052] In some embodiments, the treated aqueous solution is agitated during the contacting in step (ii).

[0066]

[0053] In some embodiments, the lithium sorbent is suspended in the treated aqueous solution. In some embodiments, the treated aqueous solution is agitated to suspend the sorbent particles when contacted with the lithium sorbent. In some embodiments, the treated aqueous solution is stirred vigorously to suspend the sorbent particles when contacted with the lithium sorbent.

[0067]

[0054] In some embodiments, the treated aqueous solution in step (ii) is at a temperature of about 0 to 100°C when contacted with the lithium sorbent. In some embodiments, the treated aqueous solution is at a temperature of about 0 to less than 100°C when contacted with the lithium sorbent. In some embodiments, the treated aqueous solution is at a temperature of about 10 to 90°C when contacted with the lithium sorbent. In some embodiments, the treated aqueous solution is at a temperature of about 20 to 90°C when contacted with the lithium sorbent. In some embodiments, the treated aqueous solution is at a temperature of about 30 to 90°C when contacted with the lithium sorbent. In some embodiments, the treated aqueous solution is at a temperature of about 40 to 90°C when contacted with the lithium sorbent.

[0068]

[0055] In some embodiments, the treated aqueous solution is contacted with the sorbent for about 20 seconds to 12 hours. In some embodiments, the treated aqueous solution is contacted with the sorbent for about 30 seconds to 12 hours. In some embodiments, the treated aqueous solution is contacted with the sorbent for about 1 minute to 12 hours. In some embodiments, the treated aqueous solution is contacted with the sorbent for about 1 minute to 10 hours. In some embodiments, the treated aqueous solution is contacted with the sorbent for about 1 minute to 8 hours. In some embodiments, the treated aqueous solution is contacted with the sorbent for about 1 minute to 6 hours. In some embodiments, the treated aqueous solution is contacted with the sorbent for about 1 minute to 5 hours. In some embodiments, the treated aqueous solution is contacted with the sorbent for about 1 minute to 4 hours; optionally, wherein the treated aqueous solution is contacted with the sorbent for about 2 minutes to 4 hours. In some embodiments, the treated aqueous solution is contacted with the sorbent for about 5 minutes to 3 hours.

[0069]

[0056] In some embodiments, the treated aqueous solution is contacted with a hydrogen manganese oxide sorbent for about 20 seconds to 12 hours. In some embodiments, the treated aqueous solution is contacted with a hydrogen manganese oxide sorbent for about 30 seconds to 12 hours. In some embodiments, the treated aqueous solution is contacted with a hydrogen manganese oxide sorbent for about 1 minute to 12 hours. In some embodiments, the treated aqueous solution is contacted with a hydrogen manganese oxide sorbent for about 1 minute to 10 hours. In some embodiments, the treated aqueous solution is contacted with a hydrogen manganese oxide sorbent for about 1 minute to 8 hours. In some embodiments, the treated aqueous solution is contacted with a hydrogen manganese oxide sorbent for about 1 minute to 6 hours. In some embodiments, the treated aqueous solution is contacted with a hydrogen manganese oxide sorbent for about 1 minute to 5 hours. In some embodiments, the treated aqueous solution is contacted with a hydrogen manganese oxide sorbent for about 1 minute to 4 hours. In some embodiments, the treated aqueous solution is contacted with a hydrogen manganese oxide sorbent for about 2 minutes to 4 hours. In some embodiments, the treated aqueous solution is contacted with a hydrogen manganese oxide sorbent for about 5 minutes to 3 hours.

[0070]

[0057] In some embodiments, water is added to the separated lithium loaded sorbent and the lithium depleted solution. In some embodiments, water is added to the separated lithium loaded sorbent to dilute the mixture to about 1 to 1000 g / L, about 200 to 900 g / L, about 400 to 900 g / L, about 600 to 900 g / L or about 700 g / L of the sorbent.

[0058] In some embodiments, the separating step (iii) and / or separating step (v) comprises a dialysis step, wherein the sorbent is washed with water and filtered to decrease the amount of a soluble impurity on the sorbent. In some embodiments, the separating step (iii) and / or separating step (v) comprises a dialysis step, wherein the sorbent is washed with water and filtered through an ultrafiltration membrane to substantially decrease the amount of a soluble impurity on the sorbent. In some embodiments, the separating step (iii) and / or separating step (v) comprise a dialysis step, wherein the sorbent is washed with water and filtered through an ultrafiltration membrane to decrease the amount of a soluble impurity on the sorbent. In some embodiments, the separating step (iii) comprises a dialysis step, wherein the lithium loaded sorbent is washed with water and filtered through an ultrafiltration membrane to decrease the amount of a soluble impurity on the sorbent. In some embodiments, the separating step (v) comprises a dialysis step, wherein the regenerated sorbent is washed with water and filtered through an ultrafiltration membrane to decrease the amount of a soluble impurity on the sorbent. In some embodiments, the water is deionized water. In some embodiments, the dialysis step reduces the conductivity of a filtrate. In some embodiments, the conductivity of the filtrate after the dialysis step is less than about 100 mS / cm, less than about 50 mS / cm, less than about 40 mS / cm, less than about 30 mS / cm, less than about 20 mS / cm, less than about 10 mS / cm, less than about 5 mS / cm, less than about 1 mS / cm, less than about 0.5 mS / cm, less than about 0.5 pS / cm, less than about 0.1 pS / cm or less than about 0.05 pS / cm.

[0071]

[0059] In some embodiments, the regenerated sorbent is recycled in the process. In some embodiments, the regenerated sorbent is recycled by repeating steps (ii) to (v) with the regenerated sorbent and a further treated aqueous solution. In some embodiments, the sorbent is recycled at least 3 times. In some embodiments, the sorbent is recycled at least 5, 10, 20, 50 or 100 times. In some embodiments, the sorbent is recycled at least 5, 10, 20, 50 or 100 times as compared to a process where the impurities are not removed / treated in the aqueous solution containing lithium.

[0072]

[0060] In some embodiments, the lithium sorbent is recycled in the process.

[0073]

[0061] In some embodiments, the lithium sorbent is treated to remove impurities from the lithium sorbent. In some embodiments, the lithium loaded sorbent is treated to remove impurities from the lithium sorbent. In some embodiments, the regenerated sorbent is treated to remove impurities from the lithium sorbent. In some embodiments, a process equipment component is treated to remove impurities. In some embodiments, the treatment comprises the removal of the impurities by one or more purification methods, depending on the nature of the impurity present. In some embodiments, the treatment comprises the use of water, an aqueous acid, an aqueous base, an organic solvent, an oxidant, a solvent extraction, a complexing agent, a chelating agent, a reducing agent, steam or heat. In some embodiments, the treatment of the lithium sorbent and / or a process equipment component is carried out in a separate container. In some embodiments, a treatment is carried out continuously in every step of the DLE process to prevent impurities from building up in the process. In some embodiments, the treatment is carried out when the impurities reach a maximum predetermined value. In some embodiments, the treatment is carried out when a flow rate through the process equipment component declines below a predetermined value, or a concentration of the impurity reaches a predetermined value.

[0074]

[0062] In some embodiments, when the lithium sorbent is recycled, concentration of the impurity on the lithium sorbent is monitored, and recycling is ceased once the concentration of the impurity reaches a predetermined value. In some embodiments, when the lithium sorbent is recycled, recycling is ceased once the sorbent performance declines by 75% on the initial performance value. In some embodiments, when the lithium sorbent is recycled, the process equipment component is monitored, and recycling is ceased once the flow rate through the process equipment component declines below a predetermined value. In some embodiments, when the lithium sorbent is recycled, the process equipment component is monitored, and recycling is ceased once the flow rate through the process equipment component declines below 75% of an initial flow rate.

[0075]

[0063] In some embodiments, the sorbent is contacted with the treated aqueous solution at about 1 to 700 g / L; or, about 1 to 500 g / L; or, about 1 to 200 g / L; or, about 1 to 100 g / L; or, about 1 to 50 g / L.

[0076]

[0064] In some embodiments, the treating in step (iv) comprises contacting the lithium loaded sorbent with an acid to produce a mixture of a lithium rich solution and a regenerated sorbent. In some embodiments, the means for treating the lithium loaded sorbent in (iv) is a source of acid. In some embodiments, the acid in step (iv) or the source of acid is selected from one or more mineral acids and / or organic acids. In some embodiments, the acid in step (iv) or the source of acid is selected from one or more of HCI, H2SO4, HBr, HI and phosphoric acid.

[0077]

[0065] In some embodiments, the acid in step (iv) or the source of acid substantially does not dissolve the sorbent.

[0078]

[0066] In some embodiments, the acid in step (iv) or the source of acid is a concentrated or dilute acid.

[0079]

[0067] In some embodiments, the treatment in step (iv) comprises contacting the lithium loaded sorbent with an oxidizing agent to produce a mixture of a lithium rich solution and a regenerated sorbent. In some embodiments, the means for treating the lithium loaded sorbent in (iii) is an oxidizing agent.

[0080]

[0068] In some embodiments, the process further comprises washing the lithium loaded sorbent; optionally, washing the lithium loaded sorbent with water and / or a chemical wash (e.g. an acid). In some embodiments, the process further comprises washing a process equipment component; optionally, washing the component with water and / or a chemical wash (e.g. an acid). In some embodiments, the process further comprises washing the lithium loaded sorbent and the process equipment component concomitantly; optionally, washing the lithium loaded sorbent and the process equipment component with water and / or a chemical wash (e.g. an acid, an oxidant, a reductant, a chelating agent and / or a combination of any two or more thereof). In some embodiments, the process further comprises washing the lithium loaded sorbent to at least partially remove an impurity (e.g. adsorbed on the sorbent and / or solid precipitates). In some embodiments, the process further comprises washing the lithium loaded sorbent to substantially remove an impurity (e.g. adsorbed on the sorbent and / or solid precipitates). In some embodiments, the process further comprises washing a process equipment component; optionally, washing the component with water and / or a chemical wash (e.g. an acid, an oxidant, a reductant, a chelating agent and / or a combination of any two or more thereof). In some embodiments, the process further comprises washing a process equipment component to at least partially remove an impurity (e.g. solid precipitates). In some embodiments, the process further comprises washing a process equipment component to substantially remove an impurity (e.g. solid precipitates). In some embodiments, the impurity is H2S. In some embodiments, the adsorbed impurity is Fe. In some embodiments, the impurity is Mn. In some embodiments, the impurity is Zn.

[0069] In some embodiments, step (iv) is performed at a temperature of about 0 to 100°C, optionally about 10 to 100°C, about 20 to 100°C, about 30 to 100°C or about 40 to 100°C.

[0081]

[0070] In some embodiments, the regenerated sorbent is reused in the process or the system. In some embodiments, the regenerated sorbent is reused in the process or the system after a treatment to reduce the concentration of the impurity.

[0082]

[0071] In some embodiments, the hydrogen manganese oxide sorbent is produced by leaching the lithium from a lithium manganese oxide with an acid.

[0083]

[0072] In some embodiments, the aqueous solution containing lithium is selected from a geothermal brine, continental brine, salar brine, sea water, concentrates from processing seawater, pre-treated brine, a waste stream from a lithium processing facility, a waste stream from a battery recycling plant, an oil well brine, formation water, produced water, fracking water, or other ground water.

[0084]

[0073] The term "comprising" as used in this specification and claims means "consisting at least in part of". When interpreting each statement in this specification and claims that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner.

[0085]

[0074] It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner.

[0086]

[0075] As used herein the term "and / or" means "and" or "or", or both.

[0087]

[0076] As used herein "(s)" following a noun means the plural and / or singular forms of the noun.

[0077] To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

[0088]

[0078] The disclosure consists in the foregoing and also envisages constructions of which the following gives examples only. Features disclosed herein may be combined into new embodiments of compatible components addressing the same or related inventive concepts.

[0089] BRIEF DESCRIPTION OF THE FIGURES

[0090]

[0079] Preferred embodiments of the disclosure will be described by way of example only and with reference to the following drawings.

[0091]

[0080] Figure 1 shows a process flow sheet for a process according to the present invention.

[0092] DETAILED DESCRIPTION OF THE INVENTION

[0093]

[0081] The chemistry of lithium-containing brines is very complex, and the presence of some impurities can significantly impair the lithium extraction process. For example, some impurities naturally present in lithium brines (e.g. H2S, Fe, Mn, Pb, Zn, etc) can strongly bind to the surface of transition metal-based oxide sorbents (e.g. chemisorption or physisorption), resulting in its surface modification. The equations 1 and 2 are some examples of the surface reaction between manganese oxide, as an example of a lithium sorbent, and H2S under pH>4. [Luther, G.W., Thibault de Chanvalon, A., Oldham, V.E. et al. Reduction of Manganese Oxides: Thermodynamic, Kinetic and Mechanistic Considerations for One- Versus Two- Electron Transfer Steps. Aquat Geochem 24, 257-277 (2018). https: / / doi.org / 10.1007 / s10498- 018-9342-1]

[0094] Mn — OH + H2S -> Mn - OH ■ H2S equation 1

[0095] Mn - 0~ + H2S -> Mn - 0~ ■ H2S equation 2

[0096]

[0082] As a result, these impurities can be transferred along with the sorbent in the lithium extraction process and result in the contamination of the final product, reducing the sorbent selectivity to lithium ions, or can accumulate in the process with the sorbent re-use. Some impurities can also cause chemical damage to the sorbent and limit its re-use in the process. Some contaminations can also be corrosive to process equipment and membranes leading to fouling of the process components.

[0097]

[0083] This invention relates to a system and a process to remove target impurities in lithium brines using adsorption media prior to the DLE process. Advantageously, the brine treatment may reduce sorbent degradation in the DLE process as compared to a DLE performed without the brine treatment. The inventors have also surprisingly found that the impurities can be carried over with the sorbent in the DLE process, resulting in the contamination of the lithium rich product which makes its conversion into battery grade lithium salt more difficult. Therefore, treating the lithium brine to remove specific impurities before contacting the brine with the sorbent may improve the chemical stability and performance of the sorbent as well as the quality of the lithium rich solution.

[0098]

[0084] The surface chemistry of metal oxide-based sorbents can be modified by exposure to brines with some target impurities during the lithium extraction process (e.g. H2S, Fe, Mn, Pb, Zn and inorganic additives). Transition metals have unoccupied "d" orbitals that can receive electrons from some molecules or ions resulting in the chemisorption or physisorption of some impurities commonly present in lithium brines. For example, when the sorbent is in contact with lithium brines containing iron, the iron can strongly bind to its surface and cannot be effectively removed by common washing procedures in the lithium extraction process. The impurities may then be desorbed and leach into the lithium rich solution, e.g. during lithium desorption in acid at low pH (e.g. below pH 2). This impurity carryover must be removed in order to make a high purity lithium rich solution. The impurities can also bind strongly to the surface of the sorbent and hinder its capacity as well as accumulate in the process resulting in process performance decline. The inventors have found that the impurities can be accumulated in the DLE process via two distinct mechanisms; (1) adsorption on the sorbent and (2) as a solid precipitate rejected by the membrane system used in the DLE process to separate the lithium sorbent particles. The mechanism (2) can also result in an increase on membrane fouling and negatively affect the separation of the lithium sorbent for re-use in the DLE process.

[0085] I mpurities above a certain size may reduce the efficiency of a DLE process as described herein. One way the impurity may reduce the efficiency of the DLE process is by clogging or fouling of a component of the process equipment, e.g., a filtration component such as a membrane system. For example, impurities that are larger than the pore size of any filtration equipment used in the DLE process, e.g. an ultrafiltration membrane, may lead to clogging or fouling of the filtration equipment. Clogging or fouling of equipment would reduce the efficiency of the process and potentially damage the equipment. The use of filtration equipment is required in the DLE process as described herein to separate the lithium sorbent for its re-use in the process. The lithium sorbent may comprise fine particles that are separated in the process using ultrafiltration membrane. Accordingly, impurities present in the lithium brine with a molecular weight above 50 kDa must be removed prior to the DLE process to prevent their accumulation in the process. In some embodiments, the impurity has a molecular weight greater than about 120 kDa, about 80 kDa or about 50 kDa. In some embodiments, the impurity has a hydration radius greater than about 0.01 pm. In some embodiments, the impurity has a hydration radius greater than about 30 nm, about 15 nm, about 8 nm.

[0099]

[0086] The preferred treatment step (i) will depend on the impurity being removed. For example, an impurity with a particle size greater than about 30 nm is preferably removed with a physical separation technique. Alternatively, an impurity with a particle size less than about 30 nm, including an impurity dissolved in the solution, is preferably removed with an adsorption media. Impurities with a particle size less than about 30 nm that are preferably removed from the solution are those that may interact with the sorbent, e.g., a reducing agent, a transition metal, an alkaline-earth metal, a post-transition metal, or an inorganic additive.

[0100]

[0087] Furthermore, some impurities in the brine, such as H2S, can also promote sorbent breakdown, which results in Mn2+leaching into solution, due to a self-disproportionation reaction. The resulting lithium rich liquor can be contaminated with these ions that are observed to leach into the solution at low pH and result in a poor-quality product. The same concept applies for other impurities that are naturally present in lithium brines with affinity to the transition metal-based oxide such as the manganese-based sorbent. The sorbent breakdown per-cycle can be calculated based on the sorbent total weight subtracting the amount lost as Mn2+. The Mn2+in solution can be measured using inductively coupled plasma - optical emission spectrometry (ICP-OES). The sorbent dissolution can be significant with the sorbent re-use in multiple lithium upload and elution cycles, thus limiting its commercial application.

[0101]

[0088] While the process has been described in relation to the carryover of impurities to the lithium rich liquor and degradation and contamination of manganese containing sorbents, those persons skilled in the art will appreciate the invention may be useful with other sorbents. The benefits of treating an aqueous solution containing lithium before contacting the solution with the sorbent may be achieved with other sorbents in which the adsorption of unwanted ions is not easily removed with washing procedures. For example, the invention may be useful for a sorbent containing a transition metal that is susceptible to chemisorption or physisorption of some target impurities (e.g. titanium, alumina based sorbents / ion exchange). The invention may also be useful to reduce the accumulation of some target impurities in the DLE process with the lithium sorbent recycling.

[0102]

[0089] The inventors have surprisingly found that the use of common oxidation methods (e.g. chemical oxidation) can result in very high chemical costs, where excess stoichiometric dose is required to effectively remove sulfide ions for example. The pH of the brine is another factor that can lead to increased chemical usage to treat target impurities in the brine (see Fernando Cadena, Robert W. Peters. Evaluation of chemical oxidizers for hydrogen sulfide control. Journal WPCF, Volume 60, Number 7). Excess oxidant may also need to be removed before contacting the brine with the sorbent. Adsorption media can be used in a pre-treatment method with the advantages of selectivity and re-use in the process combined with the removal of insoluble particles in the adsorption media bed that could negatively affect the DLE process, lithium rich liquor and / or the sorbent.

[0103]

[0090] Accordingly, the invention provides a process for extracting lithium from an aqueous solution containing lithium, the process comprising:

[0104] (i) contacting the aqueous solution containing lithium with an adsorption media to produce a treated aqueous solution,

[0105] (ii) contacting the treated aqueous solution with a lithium sorbent to produce a lithium loaded sorbent and lithium depleted solution,

[0106] (iii) separating the lithium loaded sorbent and the lithium depleted solution, (iv) treating the lithium loaded sorbent to produce a mixture of a lithium rich solution and a regenerated sorbent, and

[0107] (v) separating the lithium rich solution and the regenerated sorbent. wherein step (i) reduces the concentration of an impurity in the aqueous solution containing lithium and wherein the impurity is selected from the group consisting of a reducing agent, a transition metal, an alkaline-earth metal, a post-transition metal, an inorganic additive, an impurity with a molecular weight above 50 kDa, an impurity with a hydration radius greater than about 0.01 pm or a combination of any two or more thereof.

[0108]

[0091] In one aspect, the invention provides a process for extracting lithium from an aqueous solution containing lithium, the process comprising:

[0109] (i) contacting the aqueous solution containing lithium with an adsorption media to produce a treated aqueous solution,

[0110] (ii) contacting the treated aqueous solution with a lithium sorbent to produce a lithium loaded sorbent and lithium depleted solution,

[0111] (iii) separating the lithium loaded sorbent and the lithium depleted solution,

[0112] (iv) treating the lithium loaded sorbent to produce a mixture of a lithium rich solution and a regenerated sorbent, and

[0113] (v) separating the lithium rich solution and the regenerated sorbent. wherein step (i) reduces the concentration of an impurity in the aqueous solution containing lithium and wherein the impurity is selected from the group consisting of a reducing agent, a transition metal, an inorganic additive and a combination of any two or more thereof.

[0114]

[0092] The process of the invention comprises contacting the aqueous solution containing lithium with an adsorption media. Suitable adsorption media include, but are not limited to, a metal oxide (such as iron oxide or manganese oxide), an activated carbon, a polymeric resin or a combination of any two or more thereof. Preferably, the adsorption media is a metal oxide (such as iron oxide or manganese oxide). The adsorption media may be provided in a packed column. When used in a packed column, the adsorption media is preferably provided on a substrate. For example, the packed column may comprise a metal oxide on a carbon-based substrate, e.g. charcoal or activated carbon, or a silica-based substrate, e.g. sand. For example, the packed column may comprise an active substrate e.g. charcoal or activated carbon or a polymeric resin.

[0115]

[0093] The treatment with an adsorption media may be carried out in a container, such as an agitated tank, a recirculation tank, an adsorption bed or a packed column containing an adsorption media. The treatment may be performed under constant agitation in a stirred tank or by recirculation. The treatment may be performed continuously or in batch systems. The aqueous solution may be depressurized in a flash tank, air sparged, nitrogen sparged, placed under vacuum or put through a tortoise path prior to step (i) to lower the pressure of the brine, and / or to lower the temperature of the brine, and / or to lower the concentration of gases. In some embodiments, the aqueous solution is processed in a flash tank prior to step (i) to lower the concentration of a gas selected from CO2, H2S and / or CH4.

[0116]

[0094] The term "container" as used herein refers to a single container or a series of containers. For example, the first container may be a single container selected from an agitated tank, a recirculation tank, or a packed column containing the adsorption media. Alternatively, the first container may be a series of two or more containers selected from an agitated tank, a recirculation tank, a packed column containing the adsorption media or a combination of any two or more thereof. The second container, third container, fourth container and / or fifth container may also be a single container or series of containers, e.g., a series of two or more tanks. The container may be followed by a filter to remove the absorption media.

[0117]

[0095] The aqueous solution is treated with an adsorption media to produce a treated aqueous solution. The preferred impurity removal will depend on the composition of the aqueous solution, e.g., the impurities contained therein. For example, the aqueous solution may be treated to achieve H2S below about 10 mg / L. For example, the aqueous solution may be treated to achieve Fe below about 10 mg / L. For example, the aqueous solution may be treated to achieve Mn below about 10 mg / L. For example, the aqueous solution may be treated to achieve an impurity molecular weight limit of 50 kDa.

[0118]

[0096] The impurity may be an inorganic additive. Inorganic additives are generally compounds added during production of the aqueous solution containing lithium, e.g. chemicals used to extract and purify an oil-field brine. The inorganic additives present in the solution will vary depending on the source of the aqueous solution. Common inorganic additives that are present in brines include inorganic flocculants, such as aluminum sulfate, aluminum chloride, calcium sulphate and ferric chloride.

[0119]

[0097] The impurity with a molecular weight above 50 kDa may be a hydrocarbon, a fat, an oil, a grease, a phenol, micelles, a chemical additive, an inorganic colloid (e.g. colloidal SiC ), or a combination of any two or more thereof.

[0120]

[0098] Examples, of hydrocarbons include an aromatic hydrocarbon, e.g., benzene, toluene, ethylbenzene or xylene; a poly aromatic hydrocarbon (PAH). In some embodiments, the hydrocarbon is a C1-C12 hydrocarbon, preferably a C6-C12 hydrocarbon or a Ci-Cs hydrocarbon. The hydrocarbon may be a fluid or a dissolved gas (e.g. methane).

[0121]

[0099] The impurity may be a chemical additive. Chemical additives are generally compounds added during production of the aqueous solution containing lithium, e.g. chemicals used to extract and purify an oil-field brine. The chemical additives present in the solution will vary depending on the source of the aqueous solution. Common chemical additives that are present in brines include surfactants and flocculants. For example, the chemical additive may be an anionic, cationic, nonionic and / or an amphoteric compound. Examples of surfactants include a polyoxyethylene alkyl ether, an alkyl benzene sulfonate, an alkyl di-aminoethyl hydrochloride glycine, an alkylphenol ethoxylate and a fatty alcohol polyglycol ether. Examples of flocculants include an acrylamide-sodium acrylate copolymer and a sodium polyacrylate.

[0122]

[0100] The impurity may be water soluble (i.e. dissolved in the aqueous solution) or water insoluble (non-miscible in water).

[0123]

[0101] The impurity may be a colloid or an emulsion.

[0124]

[0102] The DLE process may comprise use of a lithium sorbent that is separated and re-used in the process with physical separation methods (e.g. a membrane with a molecular weight cut-off of 50 kDa). The presence of impurities in the brine comprising a molecular weight above 50 kDa, which is larger than the pore size of any filtration equipment used in the DLE process described herein, e.g. an ultrafiltration membrane, may lead to their accumulation in the process, clogging and / or fouling of the filtration equipment. Accordingly, it is advantageous to those impurities in the pre-treatment step to reduce such negative effects.

[0103] The impurity (e.g. the alkaline-earth metal or post-transition metal) may comprise a radioactive material. Typically, the radioactive material will be a natural occurring radioactive material (NORM) and / or a technologically enhanced naturally occurring radioactive material (TENORM). The radioactive material may include a decay product or products of the radioactive material. Examples of radioactive materials include, but are not limited to, Ra- 226, Ra-228, Pb-210, Sr-90 and a combination of any two or more thereof. In some embodiments, the radioactive material is Ra-226 and Ra-228

[0125]

[0104] Advantageously, treating the aqueous solution containing lithium to remove target impurities (e.g. H2S, Fe, Mn, Pb, Zn and others) below 10 mg / L, preferably below 1 mg / L, before contacting the aqueous solution with the sorbent may reduce degradation of the sorbent caused by impurities in the aqueous solution. The preferred impurity removal to minimize degradation of the sorbent will depend on the composition of the aqueous solution, i.e. the source of the aqueous solution. For example, when the aqueous solution containing lithium is a geothermal brine, the solution is preferably treated to produce an aqueous solution with H2S below 10 mg / L. When the aqueous solution containing lithium is an oil well brine, the solution is preferably treated to produce a treated aqueous solution with H2S and Fe below 10 mg / L. The skilled person may determine the preferred concentration of the impurity for a particular aqueous solution containing lithium by routine tests, e.g. contacting samples of the aqueous solution at different concentrations of impurities (e.g. H2S, Fe, Mn, Pb, Zn, etc.) with the sorbent then testing the sorbent with a titration method as described by Freeman and Chapman (An Improved Oxalate Method for the Determination of Active Oxygen in Manganese Dioxide, Analyst, 1971, 96, 865-869). The change in oxidation state can also be calculated based on the sorbent total weight subtracting the amount lost as Mn2+. The Mn2+in solution can be measured using for example inductively coupled plasma - optical emission spectrometry (ICP-OES). When the sorbent contains manganese, a change in oxidation state of the Mn from 4+ to 3+ / 2+ is indicative of degradation of the sorbent.

[0126]

[0105] Accordingly, the impurity may be a combination of impurities. For example, the impurity may be a combination of any two or more of a reducing agent, a transition metal, an alkaline-earth metal, a post-transition metal, an inorganic additive, an impurity with a molecular weight above about 50 kDa and an impurity with a hydration radius greater than about 0.01 pm. In some embodiments, the impurity is a combination of two or more of a reducing agent, a transition metal and an inorganic additive. In some embodiments, the impurity is a combination of H2S, Fe, Mn and Zn. In some embodiments, the impurity is a combination of H2S and Fe.

[0127]

[0106] When the impurity is a combination of impurities, each impurity may be reduced concurrently or sequentially. For example, when the impurity is a combination of two or more of H2S, Fe and Mn, each impurity may be removed concurrently by contacting the aqueous solution with an adsorption media. In another example, each impurity may be reduced sequentially, e.g. when different means are required to remove each impurity. For example, when the impurity is a combination of, e.g., impurities that are soluble or have a particle size less than 30 nm, and impurities having a particle size greater than 30 nm, the impurities that are soluble or have a particle size less than 30 nm than may reduced by contacting the solution with the adsorption media, and the impurities having a particle size greater than 30 nm may be reduced by physical separation (e.g. ultrafiltration of the solution) before or after contacting the solution with the adsorption media.

[0128]

[0107] The impurity removal step may be monitored by conventional means. For example, the removal of H2S may be monitored by colorimetric analysis (Hach H2S test). The impurity removal step may be monitored by a combination of means, e.g., by monitoring one or more impurities using different analytical methods.

[0129]

[0108] The adsorption media will typically be on a service cycle in which the media is alternated between on duty and off duty cycles. When the adsorption media is on duty cycle, the media is in contact with the aqueous solution to actively remove impurities. When the adsorption media is off duty cycle, the media is under regeneration, under maintenance or other operational process. The service cycle refers to the period the adsorption media is on duty. At the end of the service cycle, the adsorption media is taken off duty cycle, e.g. to remove accumulated impurities to allow re-use of the adsorption media. The service cycle may be determined by various means. For example, the service cycle may be determined by (1) when a capacity of the adsorption media is exhausted (i.e. the capacity of the media to adsorb the impurity is below a predetermined value), (2) a flow rate through the adsorption media declines below a predetermined value, or (3) the concentration of an impurity adsorbed on the adsorption media reaches a predetermined value. The adsorption media 1 may comprise two or more modules. Each module may be independently on duty cycle or off duty cycle. The use of multiple modules allows one module to be put on duty cycle when another module is taken off duty cycle. In this way, the adsorption media may be configured and operated such that there is always at least one module on duty cycle to facilitate a continuous operational process.

[0130]

[0109] Step (ii) and / or contacting the treated aqueous solution containing lithium with a sorbent can be referred to as the upload step. The sorbent selectively absorbs lithium into or onto its ion exchange sites and releases hydrogen ions.

[0131]

[0110] Once the lithium has been absorbed, the lithium loaded sorbent is separated from the lithium depleted solution in step (iii). This can be achieved, e.g., by filtration, as the lithium loaded sorbent largely remains a solid. When the sorbent is at low concentrations, a pre-concentration filtration method or settling can be used to concentrate the sorbent before it is further concentrated with another method. Once separated, the lithium depleted solution may be disposed of, or may be further processed, or particularly when the aqueous solution containing lithium came directly or indirectly from a ground water (for example a geothermal water), it can be reinjected into the ground.

[0132]

[0111] In some embodiments, the mixture comprising the aqueous solution containing lithium and the lithium sorbent is pumped using a pump suitable for high solids slurries, e.g., a centrifugal pump, positive displacement pump, peristaltic pump, etc.

[0133]

[0112] In some embodiments, one or more of steps (i)-(v) are performed in a batch process. In some embodiments, steps (i)-(v) are performed in a batch process. In some embodiments, one or more of steps (i)-(v) are performed in a continuous process. In some embodiments, steps (i)-(v) are performed in a continuous process.

[0134]

[0113] In order to recover the lithium from the lithium loaded sorbent, the sorbent is treated under conditions that cause the lithium to be released from the sorbent. For example, the sorbent may be contacted with an acid (for example, the sorbent may be washed or mixed with the acid). This may be referred to as the elution step or unload step. The hydrogen ions exchange for lithium in the porous sorbent structure releasing the lithium and regenerating the sorbent. The lithium loaded sorbent may be suspended in water at 1 to 1000 g / L, preferably around 700 g / L Acid may then be added to the suspended sorbent to release the lithium. HCI is the preferred acid although other acids including, but not limited to, H2SO4, HBr, HI and phosphoric acid may be used. Organic acids may be used although some, such as oxalic acid or citric acid, may dissolve the sorbent so are less preferred. The acid may be added all at once or preferably slowly (e.g. over a period of 20 minutes), the acid may be added in excess or at a 1:1 stoichiometric ratio to the lithium held by the sorbent or until a stable pH around 1-2 is achieved. Alternatively, the lithium loaded sorbent may be treated with an oxidizing agent to release the lithium and regenerate the sorbent.

[0135]

[0114] The lithium rich solution and regenerated sorbent may be separated, e.g., by filtration or other means. The lithium rich solution may be further processed (as discussed herein).

[0136]

[0115] The regenerated sorbent may be recycled in the process, i.e. reused in one or more upload steps. Accordingly, in some embodiments, the lithium extraction process comprises multiple cycles. In those embodiments, the regenerated sorbent is recycled by repeating steps (ii) to (v) with the regenerated sorbent and a further treated aqueous solution to produce a further lithium loaded sorbent, which may be subsequently regenerated to repeat the process. For example, the regenerated sorbent may be contacted with a second treated solution to produce a second lithium loaded sorbent and a second lithium depleted solution. A preferred embodiment in which the sorbent is recycled is shown in Figure 1. The cycle may be repeated to produce a third, fourth, fifth, etc. lithium loaded sorbent / lithium depleted solution. Each repetition of steps (ii) to (v) is a cycle. In some embodiments, the extraction process comprises at least 3 cycles, i.e. extraction steps (ii) to (v) are performed at least 3 times. In some embodiments, the extraction process comprises at least 5, 10, 20, 50 or 100 cycles. Advantageously, contacting the aqueous solution containing lithium with an adsorption media to remove an impurity, i.e. step (i), before contacting the aqueous solution with the sorbent reduces degradation of the sorbent and, therefore, increases the lifespan of the sorbent over multiple cycles. One of the disadvantages of not contacting the aqueous solution containing lithium with an adsorption media to remove an impurity, i.e. step (i), before contacting the aqueous solution with the sorbent is the increase on the sorbent degradation rate. The performance of the process equipment also declines with a process carried out without contacting the aqueous solution containing lithium with an adsorption media and / or a filtration process to remove an impurity, i.e. step (i).

[0116] Alternatively or additionally, the regenerated sorbent may be recycled in the process to re-extract the lithium depleted brine. Re-extraction may be useful if lithium was not effectively extracted in the first extraction (e.g. less than 90% efficiency).

[0137]

[0117] The treated aqueous solution preferably is mixed with the lithium sorbent and agitated. The lithium sorbent is usually a powder; although the sorbent could be in the form of a pellet or bead or present as a filter cake or in a column that the treated aqueous solution passes through. The sorbent and treated aqueous solution are preferably agitated together until the lithium absorbs into the sorbent. This process typically takes 40 minutes although it can take minutes to hours depending on the sorbent particle size, excess sorbent dose, temperature, pH, etc. The sorbent preferably is added in a slight excess to the amount needed to absorb the lithium e.g. in a brine containing 200 mg / L lithium, a sorbent with a capacity of 10 mg / g Li would be added at a rate of approximately >20 g / l to be in excess. Advantageously, addition of excess sorbent may decrease the process time.

[0138]

[0118] It has been found that the hotter the brine / treated aqueous solution and the faster the brine and sorbent are mixed the faster the upload process. The optimum rate of agitation will depend on the size of the container. However, in general agitation, in particular relatively high agitation, has been found to be beneficial to the upload / absorption rate. In some embodiments, agitation is affected by stirring. Surprisingly, it has been found that the temperature of the brine / aqueous solution containing lithium appears to have an effect on the lithium load capacity of the sorbent. Generally, the warmer the brine / treated aqueous solution the higher the capacity. The treated aqueous solution may be at a temperature of about 10 to 100°C (for example 100°C) when contacted with the lithium sorbent. However, preferably the treated aqueous solution is at a temperature of about 30 to 100°C when contacted with the lithium sorbent.

[0139]

[0119] Lithium sorbents are described, for example in Johnson Matthey "Lithium Recovery from Aqueous Resources and Batteries: A Brief Review" TechnoL Rev., 2018, 62, (2), 161-176. The lithium sorbent may be a metal oxide-based ion exchange sorbent. For example, suitable metal oxide-based ion exchange sorbents may include a hydrogen manganese oxide, a hydrogen titanium oxide, a hydrogen manganese phosphate, a hydrogen iron phosphate, a hydrogen aluminium oxide and / or a hydrogen copper oxide. Conventional sorbents capable of absorbing lithium known in the art may be useful in the invention, e.g., those formed from sorbent precursors such as LiTiC , Li2TiC>3, Li4TiC>2, Li^iC , LiyTi C^, LiM^C , Li1.67Mn1.67O4, Li1.33Mn1.67O4, Lix.2AI(OH)3, UAIO2, LiMnPO4, LiFePO4 and / or LiCuO2. Such sorbent precursor may be activated, if required, to form the lithium sorbent, e.g. by treatment with an acid to exchange the lithium for hydrogen. The lithium sorbent is preferably a hydrogen manganese oxide sorbent or a hydrogen titanium oxide sorbent, preferably a hydrogen manganese oxide sorbent. The sorbent is preferably selected from lambda-phase manganese sorbents (A-MnC ) also known as lithium manganese oxide (LMO) sorbents.

[0140]

[0120] For example, a hydrogen manganese oxide sorbent may be made by heating (for example in a furnace) solid manganese oxide with a lithium source (for example a lithium salt) to make a lithium manganese oxide. The lithium manganese oxide may be then treated with an acid to exchange the lithium for hydrogen to produce a hydrogen manganese oxide sorbent.

[0141]

[0121] The lithium sorbent may be in a micronised form. For example, the lithium sorbent may comprise particles having a particle size below 100 pm and potentially much smaller such as 0.1 pm. In some embodiments, the micronized lithium sorbent may have an average particle size of less than about 100 pm. In some embodiments, the micronized lithium sorbent has a particle size distribution ranging from about 100 to 0.01 pm. In some embodiments, the micronized lithium sorbent has a particle size distribution ranging from about 10 to 0.1 pm.

[0142]

[0122] The amount of sorbent used in step (ii) is preferably in excess dose to the amount of lithium in the aqueous solution. For example, the sorbent dose may be based on a 10 mg / g capacity (mg of lithium / grams of sorbent). Preferably the sorbent in step (ii) is in an amount to provide a capacity of about over 1 to 3 times the amount of lithium in the aqueous solution.

[0143]

[0123] The aqueous solution containing lithium may be obtained from a range of sources, for example, geothermal brine, salar brine, sea water, formation waters, concentrates from processing seawater, a waste stream from a lithium processing facility, a waste stream from a battery recycling plants, oil well brines, other ground water. For example, fracking water with chemicals added during the drilling and fracking process. For example, geothermal brine may be used which has been processed by a silica extraction plant to remove or reduce silica content. Some sources may be naturally warm (for example 40 °C) without the need to heat the aqueous solution containing lithium, for example a geothermal source. Some sources will be cold brines that do not need to be heated.

[0144]

[0124] Also described is a system for carrying out the DLE process. Accordingly, in one aspect described herein is a system for extracting lithium from an aqueous solution containing lithium, the system comprising:

[0145]

[0125] In one aspect provided herein is a system for extracting lithium from an aqueous solution containing lithium, the system comprising:

[0146] (i) a first container for contacting the aqueous solution containing lithium with an adsorption media, wherein the first container comprises an absorption bed or column comprising the adsorption media;

[0147] (ii) a second container for contacting the treated aqueous solution with a lithium sorbent to produce a lithium loaded sorbent and lithium depleted solution;

[0148] (iii) a first separating device to separate the lithium loaded sorbent and the lithium depleted solution;

[0149] (iv) means for treating the lithium loaded sorbent to produce a lithium rich solution and a regenerated sorbent; and

[0150] (v) a second separating device to separate the lithium rich solution and the regenerated sorbent.

[0151]

[0126] In one aspect provided herein is a system for extracting lithium from an aqueous solution containing lithium, the system comprising:

[0152] (i) a first container for contacting the aqueous solution containing lithium with an adsorption media, wherein the first container comprises an absorption bed or column comprising the adsorption media;

[0153] (ii) a second container for contacting the treated aqueous solution with a lithium sorbent to produce a lithium loaded sorbent and lithium depleted solution;

[0154] (iii) a first separating device to separate the lithium loaded sorbent and the lithium depleted solution;

[0155] (iv) a source of acid for treating the lithium loaded sorbent to produce a lithium rich solution and a regenerated sorbent; and

[0156] (v) a second separating device to separate the lithium rich solution and the regenerated sorbent.

[0127] Various embodiments are described with reference to the Figures. Throughout the Figures and specification, the same reference numerals may be used to designate the same or similar components, and redundant descriptions thereof may be omitted.

[0157]

[0128] The following non-limiting examples are provided to illustrate the present invention and in no way limit the scope thereof.

[0158] EXAMPLES

[0159]

[0129] An adsorption media has been used to treat brines containing different impurities. The process involves a brine pre-treatment step prior to contacting the brine with the lithium sorbent.

[0160]

[0130] A sorbent treatment was also carried out to test the removal of the impurities that can accumulate on the lithium sorbent and / or in the in the DLE process equipment.

[0161]

[0131] Different brine samples have been tested to validate brine pre-treatment methods and any other treatment required to decrease the contamination in the DLE process. The sorbent loss in wt.% was used as a measure of the effectiveness of the brine pre-treatment. The sorbent degradation was tested by measuring the amount of Mn2+in solution after each lithium desorption with acid per DLE cycle. The concentration of manganese in solution was measured by ICP-OES and the sorbent loss wt.% was calculated based on the sorbent mass lost per cycle divided by the initial sorbent mass in the process. The sorbent was regenerated for re-use after every lithium adsorption and desorption cycle in the DLE process.

[0162] Example 1: Lithium brine pre-treatment trial - H2S contamination

[0163]

[0132] In this example a geothermal brine was treated with green sand filter at a fixed filtration bed volume of 1.5 kg. The trial was performed to test the efficacy and capacity of the green sand filter as a brine treatment method to remove target impurities in geothermal brine such as H2S. The H2S concentration was tested in the original brine samples using a colorimetric test from Hach (Sulfide, Methylene Blue Method - 10254) as one example of the contaminants present in the brine. This test is recommended to test H2S in oil and gas field waters and it could also be used for geothermal water. The H2S measured in the fresh geothermal and oil formation brines varied from 10 to 20 mg / L in the examples provided. The sorbent loss was monitored in the DLE process comparing the treated and non-treated brine samples. The brine was filtered through a column with the green sand filter and the resulting pre-treated brine was tested in the DLE process comparing the volume of brine treated per filtration bed volume. The capacity of the adsorption media was tested to investigate the total brine flow that can be processed before the media exhaust its capacity.

[0164]

[0133] The sorbent loss (wt.%) in the DLE process was used as a metric to evaluate the efficacy of the green sand filter to treat a natural geothermal brine. The sorbent degradation in the DLE process with the non-treated brine was 3.89 wt.%. On the other hand, only 0.45 wt.% sorbent loss was observed for the pre-treated brine with green sand. On average the green sand showed 0.3 kg / l capacity with an estimated 100 mg / L of H2S being treated with the total brine volume processed. At the end of a service cycle the filtration bed can be regenerated for re-use. The filtration bed size can be optimized to the brine flow and impurity concentrations to be treated based on the brine type tested. The green sand filter also can be effective in other brine chemistries to treat different contaminants in aqueous solutions including H2S, Fe, Mn, Pb, etc.

[0165] Table 1. Brine pre-treatment using green sand filter to treat a natural geothermal brine containing about 20 mg / L of H2S.

[0166] Example 2: Lithium brine pre-treatment trial - Iron contamination

[0167]

[0134] Example 2 shows the effect of iron in natural brines on the DLE process. An oilfield brine sample was tested as an example of natural brine containing iron as an impurity. The iron concentration in the raw brine was 13.89 mg / L. The raw brine was tested in a small bench scale DLE test to evaluate the sorbent loss (wt.%) and purity of the lithium rich product produced in the DLE process. Two treatment methods were tested to remove iron in the brine and the treated bine samples were also tested and compared with the raw brine tests. The treatment methods consisted of a column packed with a filtration media. In one treatment the brine was filtered using a green sand filter. In another treatment the brine was filtered using activated carbon. The final iron concentration in the treated brine samples was below 1 mg / L for both treatments, as shown in Table 2. Interestingly, the iron removal not only prevented sorbent loss, but also reduced the contamination in the lithium rich solution in the elution step. The lithium rich solution purity is a very important parameter of the DLE process to meet battery grade specifications. Therefore, iron removal is beneficial prior to the DLE process to obtain a higher purity product.

[0168] Table 2. Summary of trial data testing different adsorption media to treat an oilfield brine as an example of natural brine with Fe as contamination.

[0169] Example 3: Impurities in the DLE treatment trial - Fe, Mn and Pb contamination

[0170]

[0135] A treatment was carried out in the DLE process to reduce the concentration of target contamination that can accumulate on the lithium sorbent and / or process equipment in the DLE process. In this trial the lithium brine was not pre-treated to remove the target contamination to test the accumulation of some target impurities such as Fe, Mn and Pb as an example of impurities present in most underground fluids, such as oilfield brine, geothermal brine and processed water. The lithium sorbent was contacted with the lithium brine containing about 400 mg / L Li, 100 mg / L Fe, 800 mg / L Mn and 50 mg / L Pb. The concentration of the lithium and the target contamination present in the lithium brine was monitored in the DLE process steps. The retention rate by adsorption on the sorbent and / or by the formation of solid precipitates were summarized as the retention rate in the lithium upload step. The removal of the target contamination was tested in the elution process using excess acid as a treatment method. The desorption and / or redissolution rate of the target impurities was monitored with the addition of excess acid in elution with the pH from 1.5 to 0.5. The summary of the results is shown in Table 3.

[0171]

[0136] The concentration of lithium as well as the target impurities present in the lithium brine all decreased in the lithium uploaded step of the DLE process. The target impurities are possibly being absorbed onto the lithium sorbent and / or precipitated as solids and rejected by the membrane separation process with the lithium sorbent, resulting in their accumulation in the DLE process. These impurities were not effectively removed with the sorbent dialysis process resulting in their carryover into the elution step of the DLE process. In the elution step, the acid was added stoichiometrically to the concentration of lithium uploaded by the lithium sorbent. In the example shown in Table 3, the lithium exchange is the first reaction to take place at pH 1.5 achieving above 90% Li recovery efficiency. The target impurities are shown to be desorbed at about 71.4% for Mn, 41.7% for Fe and 9.5% Pb at pH 1.5. The remaining impurities are shown to be desorbed and / or redissolved further in solution with the increase on the acid dose, with the pH change from pH = 1.5 down to pH=0.5. The maximum removal rate for the target impurities was at pH=0.5 with 109.7% Mn, 100% Fe and 38.2% Pb measured in the solution as dissolved impurities. The Mn desorption > 100% was due to a combination of the Mn from the brine and Mn from the lithium sorbent which is a lithium manganese oxide that undergoes a disproportionation reaction resulting in its degradation in the elution step of the DLE process.

[0172]

[0137] The use of excess acid in the elution step of the DLE process is shown to be effective to increase the removal rate of the target contamination that can accumulate in the DLE process. Therefore, the use of the brine pre-treatment and / or treatment processes during the DLE process to remove and / or reduce the concentration of target impurities enables the commercial scale processing of lithium brines.

[0173] Table 4. Removal of target impurities in the DLE as a treatment process in the elution step with excess acid.

Claims

CLAIMS1. A process for extracting lithium from an aqueous solution containing lithium, the process comprising:(i) contacting the aqueous solution containing lithium with an adsorption media to produce a treated aqueous solution and a loaded adsorption media, and separating the treated aqueous solution and the loaded adsorption media,(ii) contacting the treated aqueous solution with a lithium sorbent to produce a lithium loaded sorbent and lithium depleted solution,(iii) separating the lithium loaded sorbent and the lithium depleted solution,(iv) treating the lithium loaded sorbent to produce a mixture of a lithium rich solution and a regenerated sorbent, and(v) separating the lithium rich solution and the regenerated sorbent; wherein step (i) reduces the concentration of an impurity in the aqueous solution containing lithium and wherein the impurity is a reducing agent, a transition metal, an alkaline-earth metal, a post-transition metal, an inorganic additive, an impurity with a molecular weight above about 50 kilo-Daltons (kDa), an impurity with a hydration radius greater than about 0.01 pm, or a combination of any two or more thereof.

2. The process of claim 1, wherein the impurity is a reducing agent, a transition metal, an inorganic additive and a combination of any two or more thereof.

3. The process of claim 1 or 2, wherein the adsorption media is a metal oxide (such as iron oxide or manganese oxide), activated carbon, a polymeric resin or a combination of any two or more thereof.

4. The process of claim 3, wherein the metal oxide is provided on a substrate, e.g., a carbon-based substrate or a silica-based substrate (e.g. sand, zeolite).

5. The process of claim 1, wherein the adsorption media is a by-product of the process, e.g., wherein the by-product is a calcined by-product such as an oxide, e.g., whereinthe by-product of the process is manganese carbonate, manganese hydroxide, manganese oxide or a combination of any two or more thereof.

6. The process of any one of claims 1 to 5, wherein the adsorption media is provided in a packed column or an adsorption bed.

7. The process of any one of claims 1 to 6, wherein the reducing agent is H2S; and / or the transition metal is Fe, Mn or a combination thereof; and / or the inorganic additive is a flocculant (e.g. aluminum sulfate, aluminum chloride, calcium sulphate, ferric chloride or a combination of any two or more thereof).

8. The process of claim 1, wherein the alkaline earth metal is Ca, Sr, Ba, Ra or a combination of any two or more thereof; or the alkaline earth metal is Sr-90, Ra-226, Ra-228 or a combination of any two or more thereof; preferably wherein the alkaline earth metal is Ra-226, Ra-228, Sr-90 or a combination thereof; and / or the post- transitional metal is Pb, Bi, Al or a combination of any two or more thereof; or the alkaline earth metal is Pb-210, Bi-209 or a combination of any two or more thereof; preferably wherein the post-transitional metal is Pb-210, Bi-209 or a combination thereof.

9. The process of any one of claims 1 to 7, wherein the reducing agent is H2S and the transition metal is Fe or Mn.

10. The process of claim 1, wherein the impurity comprises an impurity with a molecular weight greater than about 120 kDa or the impurity comprises an impurity with a molecular weight greater than about 80 kDa.

11. The process of claim 1, wherein the impurity comprises an impurity with a hydration radius greater than about 30 nm or the impurity comprises an impurity with a hydration radius greater than about 15 nm or the impurity is an impurity with a hydration radius greater than about 8 nm.

12. The process of any one of claims 1 to 11, wherein the temperature of the aqueous solution before and during the contacting in step (i) is 0 °C to 100 °C.

13. The process of any one of claims 1 to 12, wherein the aqueous solution is processed in a flash tank, air sparged, nitrogen sparged, placed under vacuum or put through a tortoise path prior to step (i) to lower the pressure of the aqueous, and / or to lower the temperature of the aqueous solution, and / or to lower the concentration of gases, e.g. a gas selected from CO2, H2S, CH4, volatile organic carbon or a mixture of any two or more thereof.

14. The process of any one of claims 1 to 13, wherein the concentration of the impurity is reduced in step (i) to below about 10 mg / L, preferably below about 5 mg / L, more preferably below about 1 mg / L.

15. The process of any one of claims 1 to 14, wherein the concentration of at least two impurities selected from the group consisting of H2S, Fe, Mn, Zn and an inorganic additive is reduced in step (i); optionally, wherein the concentration of H2S, Fe and Mn is reduced in step (i).

16. The process of any one of claims 1 to 15, wherein the impurity comprises a combination of any two or more of a reducing agent, a transition metal, an alkaline- earth metal, a post-transition metal, an inorganic additive, an impurity with a molecular weight above about 50 kilo-Daltons (kDa) and an impurity with a hydration radius greater than about 0.01 pm; optionally, wherein the impurity comprises a combination of any three or more of a reducing agent, a transition metal, an alkaline- earth metal, post-transition metal, an inorganic additive, an impurity with a molecular weight above about 50 kilo-Daltons (kDa) and an impurity with a hydration radius greater than about 0.01 pm.

17. The process of any one of claims 1 to 16, wherein the impurity comprises a combination of two or more of H2S, Fe, Mn and Zn; or the impurity is a combination of H2S, Fe, Mn, Zn and an inorganic additive (e.g. aluminum sulfate, aluminum chloride, calcium sulphate, ferric chloride or a combination of any two or more thereof); or the impurity is a combination of two or more of H2S, Fe, Mn, Pb, Ra and Zn; or the impurity is a combination of two or more H2S, Fe, Mn, Pb, Ra, Zn and animpurity with a molecular weight of above 50 kDa concentration below about 10 mg / L, preferably below about 1 mg / L.

18. The process of any one of claims 1 to 17, wherein when the impurity comprises a combination of impurities, the concentration of each impurity is reduced concurrently or sequentially in step (i).

19. The process of any one of claims 1 to 18, wherein step (i) comprises monitoring the concentration of the impurity in the aqueous solution comprising lithium and contacting the aqueous solution with the adsorption media to reduce the concentration of the impurity below a predetermined level; preferably to reduce the concentration of the impurity below about 10 mg / l, more preferably below about 1 mg / L.

20. The process of claim 1, wherein step (i) is monitored until the concentration of H2S is below about 10 mg / L by colorimetric analysis (Hach H2S test); step (i) is monitored until the concentration of the impurity having a molecular weight below 50 kDa is below about 10 mg / L.

21. The process of claim 1, wherein step (i) comprises measuring the concentration of H2S, Fe, Mn, Zn and an inorganic additive (e.g. aluminum sulfate, aluminum chloride, calcium sulphate, ferric chloride or a combination of any two or more thereof), and if present in a concentration above about 10 mg / L, reducing the concentration of each impurity to below about 10 mg / L, preferably below about 1 mg / L.

22. The process of claim 1, wherein the treated aqueous solution has a H2S concentration below about 10 mg / L (preferably below about 1 mg / L), an Fe concentration below about 10 mg / L (preferably below about 1 mg / L), a Mn concentration below about 10 mg / L (preferably below about 1 mg / L), an inorganic additive (e.g. aluminum sulfate, aluminum chloride, calcium sulphate, ferric chloride or a combination of any two or more thereof) concentration below about 10 mg / L (preferably below about 1 mg / L), wherein the concentration of at least one of H2S, Fe, Mn or the inorganic additive is reduced relative to the aqueous solution comprising lithium before step (i).

23. The process of any one of claims 1 to 22, wherein the treated aqueous solution obtained in step (i) has a H2S concentration below about 10 mg / L, preferably below about 1 mg / L; and / or the treated aqueous solution obtained in step (i) has an Fe concentration below about 10 mg / L, preferably below about 1 mg / L; and / or the treated aqueous solution obtained in step (i) has a Mn concentration below about 10 mg / L, preferably below about 1 mg / L; and / or the treated aqueous solution obtained in step (i) has an aluminum sulfate, aluminum chloride, calcium sulphate and ferric chloride concentration below about 10 mg / L, preferably below about 1 mg / L.

24. The process of any one of claims 1 to 23, wherein step (i) further comprises treating the aqueous solution comprising lithium with a physical separation technique, e.g. wherein the physical separation technique is microfiltration or ultrafiltration; optionally wherein the physical separation technique is ultrafiltration and the ultrafiltration comprises the use of a hollow fiber membrane and / or a crossflow system.

25. The process of any one of claims 1 to 24, wherein the adsorption media is alternated between on duty and off duty cycles, wherein on duty cycle means the media is in contact with the aqueous solution to actively remove contaminants and off duty cycle means the media is under regeneration, under maintenance or other operational process.

26. The process of any one of claims 1 to 25, wherein the adsorption media comprises at least two modules such that one module may be on duty cycle while the other is off duty cycle to facilitate a continuous operational process.

27. The process of any one of claims 1 to 26, wherein the end of a service cycle of the adsorption media is determined when (1) a capacity of the media to adsorb the impurity is below a predetermined value, (2) a flow rate through the adsorption media declines below a predetermined value, or a concentration of the impurity reaches a predetermined value.

28. The process of any one of claims 1 to 27, wherein the adsorption media can be regenerated at the end of a service cycle, e.g. by treating the adsorption media withan aqueous acid, an aqueous base, an organic solvent, an oxidant, a solvent extraction, a complexing agent, a chelating agent, a reducing agent, steam or heat and / or the adsorption media is backwashed to remove the impurity, e.g., in the filter bed.

29. The process of any one of claims 1 to 28, wherein the lithium sorbent is a metal oxide-based ion exchange sorbent such as a hydrogen manganese oxide sorbent or hydrogen titanium oxide sorbent; preferably, the metal oxide-based ion exchange sorbent is a hydrogen manganese oxide sorbent.

30. The process of any one of claims 1 to 29, wherein the sorbent is in a micronised form, e.g. wherein the sorbent has an average particle size of about 100 pm or less.

31. The process of any one of claims 1 to 30, wherein the treated aqueous solution in step (ii) is at a temperature of about 0 to 100°C when contacted with the lithium sorbent, preferably the treated aqueous solution is at a temperature of about 0 to less than 100°C, about 10 to 90°C, about 20 to 90°C, about 30 to 90°C or about 40 to 90°C when contacted with the lithium sorbent.

32. The process of any one of claims 1 to 31, wherein the treated aqueous solution is contacted with the lithium sorbent for about 20 seconds to 12 hours, about 30 seconds to 12 hours, about 1 minute to 12 hours, about 1 minute to 10 hours, about 1 minute to 8 hours, about 1 minute to 6 hours, about 1 minute to 5 hours, about 1 minute to 4 hours, about 2 minutes to 4 hours or about 5 minutes to 3 hours.

33. The process of any one of claims 1 to 32, wherein the separating step (iii) and / or separating step (v) comprises a dialysis step, wherein the sorbent is washed with water and filtered to decrease the amount of a soluble impurity on the sorbent, preferably wherein the conductivity of the filtrate after the dialysis step is less than about 100 mS / cm.

34. The process of any one of claims 1 to 32, wherein the process further comprises washing the lithium loaded sorbent to at least partially remove the impurity; optionally, washing the lithium loaded sorbent with water and / or a chemical wash(e.g. an acid); and / or washing a process equipment component to at least partially remove the impurity; optionally, washing the component with water and / or a chemical wash (e.g. an acid).

35. The process of any one of claims 1 to 34, wherein the process further comprises washing the lithium loaded sorbent and the process equipment component concomitantly; optionally, washing the lithium loaded sorbent and the process equipment component with water and / or a chemical wash (e.g. an acid, an oxidant, a reductant, a chelating agent and / or a combination of any two or more thereof).

36. The process of any one of claims 1 to 35, wherein the treating in step (iv) comprises contacting the lithium loaded sorbent with an acid to produce a mixture of a lithium rich solution and a regenerated sorbent; optionally, wherein the acid in step (iv) is selected from mineral acids and / or organic acids, preferably the acid is selected from one or more of HCI, H2SO4, HBr, HI, phosphoric acid and a mixture of any two or more thereof.

37. The process of any one of claims 1 to 36, wherein the aqueous solution containing lithium is selected from a geothermal brine, continental brine, salar brine, sea water, concentrates from processing seawater, pre-treated brine, a waste stream from a lithium processing facility, a waste stream from a battery recycling plant, an oil well brine, formation water, produced water, fracking water, or other ground water.

38. The process of any one of claims 1 to 37, wherein the regenerated sorbent is recycled in the process; optionally, wherein the regenerated sorbent is recycled by repeating steps (ii) to (v) with the regenerated sorbent and further treated aqueous solution; optionally, where the sorbent is recycled at least 3 times, e.g. the sorbent is recycled at least 5, 10, 20, 50 or 100 times.

39. A system for extracting lithium from an aqueous solution containing lithium, the system comprising:(i) a first container for contacting the aqueous solution containing lithium with an adsorption media to reduce the concentration of an impurity in the aqueous solution, wherein the first container comprises (a) an absorption bed or columncomprising the adsorption media, and / or (b) a filtration system utilising a pore size of less than 0.02 pm or a molecular weight cut-off of 50 kDa or smaller,(ii) a second container for contacting the treated aqueous solution with a lithium sorbent to produce a lithium loaded sorbent and lithium depleted solution,(iii) a first separating device to separate the lithium loaded sorbent and the lithium depleted solution,(iv) means for treating the lithium loaded sorbent to produce a mixture of a lithium rich solution and a regenerated sorbent, and(v) a second separating device to separate the lithium rich solution and the regenerated sorbent.

40. The system of claim 39, wherein the column comprises a metal oxide (e.g. an iron oxide or a manganese oxide) on a substrate (e.g. a carbon-based substrate or a silica- based substrate).

41. The system of claim 39 or 40, wherein the adsorption media comprises at least two modules such that one module may be on duty cycle while the other is off duty cycle to facilitate a continuous operational process.

42. The system of any one of claims 39 to 41, wherein the first container comprises means for measuring a chemical composition of the aqueous solution, e.g., colorimetric analysis Hach Mn test, ICP-OES, Flame AA or a combination of any two or more thereof; and / or the first container comprises means for measuring the impurity with a molecular weight above 50 kDa, e.g., an ICP-OES analyzer, a Flame AA analyzer, laser diffraction analysis, turbidity meter, dynamic light scattering, Silt Density Index, or a combination of any two or more thereof.

43. The system of and one of claims 39 to 42, wherein the system further comprises a third container to regenerate the adsorption media.

44. The system of any one of claims 39 to 43, wherein the system further comprises a fourth container for storing the impurity.

5. The system of any one of claims 39 to 44, wherein the system further comprises a fifth container for storage, disposal or reinjection underground of the lithium depleted solution.

Images