Improved systems and methods for metals recovery from lithium-ion batteries

Abstract

Black mass from spent lithium batteries is leached for the recovery of various metals in a process involving precipitation, solvent exchange, ion exchange, and salt decomposition to produce multiple product streams for the recovery of pure valuable products. Most typically, the process is a closed-loop process that can produce metallic cobalt and nickel, EMD, and high purity lithium hydroxide or lithium carbonate products with minimal generation of waste streams.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to co-pending U.S. Provisional Patent Application No. 63 / 321,897, filed March 21, 2022, the contents of which are incorporated herein by reference.

[0002] The field of the invention is that of metal recovery from lithium batteries, and in particular the recovery of lithium, cobalt, copper, manganese and nickel from black mass. [Background technology]

[0003] The background statement includes information that may be useful in understanding the present invention. The background statement is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[0004] All publications and patent applications herein are incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. In the event that a definition or use of a term in a cited reference contradicts or is contrary to a definition of such term set forth in this specification, the definition of such term set forth in this specification shall apply and the definition of such term in the reference shall not apply.

[0005] The production and use of lithium-ion batteries has increased dramatically worldwide over the past decade, placing a significant strain on the supply of raw materials necessary to manufacture such batteries. Moreover, further increases in demand are projected for at least the next two decades. Unfortunately, the sourcing and processing of raw materials is almost exclusively dependent on foreign (non-U.S.) countries, exposing the U.S. economy to significant supply and price vulnerability.

[0006] While recycling of lead-acid batteries has become an integral part of the resupply of lead for the manufacture of new lead-acid batteries, recycling of lithium-ion batteries is less developed. Among other factors, there is a relatively wide variety of form factors (battery packs, modules, cylindrical cells, prismatic cells, pouch cells, etc.), available materials (defective cells, scrap metal, slurries, and powders, etc.), and cathode chemistries (lithiated cobalt oxide, lithiated nickel-cobalt-aluminum oxide, lithiated nickel-cobalt-manganese oxide, lithiated nickel-cobalt-manganese-aluminum oxide, lithiated nickel oxide, and lithiated manganese oxide, etc.). In addition, the relative amounts of transition metals used in lithium-based batteries vary widely among lithium-ion batteries, which typically complicates the recovery of lithium and other valuable metals from lithium-ion batteries. Furthermore, there are similar supply challenges for these valuable metals, such as nickel, cobalt, and manganese, and many lithium recovery processes are unable to fully address the recycling of these elements. An overview of currently known lithium-ion battery processes is presented elsewhere (see Batteries 2019, 5, 68; doi:10.3390 / batteries5040068).

[0007] Solvent-based processes are often used to recover valuable metals and metal salts from lithium battery waste. For example, US Patent Publication No. 2021 / 0317547 teaches a hydrometallurgical process for recovering metals from used lithium batteries, in which an aqueous hydrobromic acid leach solution is contacted with the electrode material to extract the metals. The extract thus obtained is then subjected to precipitation and / or cathodic electrodeposition to obtain the target metals. In another known method, such as that disclosed in US Patent Publication No. 2021 / 0344058, CO2 is used as the leach solution, and the leach solution is then subjected to precipitation and roasting to obtain cobalt and lithium materials. In yet another known method, as taught in US Patent Publication No. 2022 / 0009793, metal sulfates are obtained from the mother liquor for further processing. Similarly, U.S. Patent Application Publication No. 2022 / 0013815 teaches the use of sulfuric acid as a leaching fluid in which oxides of cobalt, nickel, and manganese are dissolved using reduction with sulfurous acid gas.

[0008] In many such known recovery methods, further processing is often necessary to obtain the metal or metal salt in the desired purity and yield. For example, cobalt can be formed by electrolysis in an electrochemical process, for example as described in Hydrometallurgy 178 (2018) 19-29. Metallic manganese and electrolytic manganese dioxide can be produced simultaneously in an anion exchange membrane reactor, as described in Bulletin Of The Georgian National Academy Of Sciences, vol. 2, no. 4, 2008. In yet another known method, lithium is recovered from a leachate that is treated using an electrodialyzer, as taught in JP-A-2012 / 234732. Similarly, lithium hydroxide is prepared from a lithium sulfate solution using an electrodialysis process, as described in WO-A-2013 / 159194. Unfortunately, all or almost all of these known processes require complex operations to generate separate product streams, require subsequent processing of the product streams, and are usually not suitable for closed-loop processes to so reduce waste streams. Furthermore, many known methods for metal recovery recover the metals in a salt form that requires further processing to yield the corresponding metal.

[0009] To simplify the operation, a sequential solvent extraction process such as that described in US Patent Application Publication No. 2022 / 0205064 can be used. Although at least conceptually simpler, various difficulties nevertheless remain. Among other problems, such sequential solvent extraction generates multiple liquid streams that require complex handling and adjustment. Moreover, in most cases, such sequential solvent stripping does not allow for an integrated process in which the solvent (and especially the leach solution) can be recycled. Moreover, the metals so recovered are usually formed as metal salts that require further processing to the corresponding pure non-lithium metals.

[0010] Thus, although various systems and methods for recovering metals from lithium batteries are known in the art, all or almost all of them suffer from some drawbacks. Thus, there remains a need for improved methods for recovering metals from lithium batteries, particularly for recovering lithium, manganese, cobalt, copper, and nickel from black mass. Summary of the Invention [Problem to be solved by the invention]

[0011] The subject of the present invention are various plant configurations, systems and methods for metal recovery from spent lithium batteries, where multiple metals are recovered in high purity in a closed loop process that allows recycling of the leaching solvent. Advantageously, the contemplated systems and methods reduce total solvent usage and waste stream generation, while at the same time allowing for a simple and efficient process flow. [Means for solving the problem]

[0012] In one aspect of the inventive subject matter, the inventors contemplate a method of recovering metals from spent lithium batteries comprising the steps of: leaching a plurality of different metals in ionic form from the battery material with a leach solution to produce a rich leach solution; another step of removing a first metal from the rich leach solution by electroplating to produce a treated leach solution; a further step of removing a second metal from the rich leach solution by precipitation to produce a further treated leach solution; a further step of removing a third metal and optionally a fourth metal from the further treated leach solution by solvent exchange to produce a third metal and optionally a fourth metal depleted leach solution; and a further step of treating the third metal and optionally a fourth metal depleted leach solution in a salt decomposition unit to regenerate at least a portion of the leach solution to produce a metal hydroxide solution and an effluent, wherein at least a portion of the metal hydroxide solution is used in the step of removing the second metal and / or the step of removing the third metal and optionally a fourth metal. Optionally, at least a portion of the effluent is used in a leaching step.

[0013] In some embodiments, the battery material comprises black mass, and the plurality of different metals comprises lithium ions and further comprises copper ions, aluminum ions, iron ions, cobalt ions, manganese ions, and / or nickel ions. In other embodiments, the battery material comprises a treated black mass from which the lithium ions have previously been removed. In such cases, the metal hydroxide solution is sodium hydroxide, potassium hydroxide, or calcium hydroxide. Most typically, the leach solution is sulfuric acid or methanesulfonic acid, and may further contain a chelating agent (e.g., EDTA).

[0014] In a particular embodiment of the present subject matter, the first metal is copper, and the electroplating of copper typically uses preferential electroplating of copper onto a flow-through cathode (e.g., graphite felt) and / or a solid cathode (e.g., stainless steel or titanium), and / or the second metal is aluminum and / or iron. In a further embodiment of the present subject matter, the third metal is cobalt and / or manganese. Preferably, the cobalt and / or manganese are recovered from the organic solvent of the solvent exchange using an acid, and the cobalt and / or manganese are plated as metallic cobalt and as EMD in one electrolytic cell. It is further contemplated that the optional fourth metal is nickel, and the fourth metal is removed in another solvent exchange. The nickel is then plated as metallic nickel in the electrolytic cell. As will be readily understood, the solvent exchange uses a portion of the regenerated leach solution and / or metal hydroxide solution from the salt decomposition unit.

[0015] In yet another aspect of the inventive subject matter, the salt decomposition unit includes at least two salt decomposers. In a typical example, a first portion of the metal hydroxide solution of one of the at least two salt decomposers is further processed to produce LiOH or LiOH·H2O product or lithium carbonate solution or lithium carbonate precipitate, and / or a second portion of the metal hydroxide solution is used in the leaching step and / or the step of removing the second metal. The second portion of the metal hydroxide solution may also be used in the step of removing the third metal and optionally the fourth metal.

[0016] If desired, contemplated systems may further include an ion exchange or chelating resin to remove metal ion impurities from the third metal and optionally the fourth metal depleted leach solution prior to feeding the third metal and optionally the fourth metal depleted leach solution to the salt decomposition unit.

[0017] Various objects, features, aspects and advantages of the subject invention will become more apparent from the following detailed description of preferred embodiments, taken in conjunction with the accompanying drawings in which like numerals represent like elements and in which: [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is an exemplary simplified schematic process flow diagram for metals recovery from black mass in accordance with the present subject matter. [Diagram 2] FIG. 2 is a more detailed exemplary process flow diagram for metals recovery from black mass in accordance with the subject matter of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The inventors have discovered various systems and methods for recovering metals from lithium batteries, particularly from the black mass of lithium batteries, in which the leachate is subjected to a closed-loop process that uses precipitation, solvent extraction, and salt decomposition to enable the recovery of various valuable metals such as copper, cobalt, manganese, nickel, and lithium. Advantageously, the systems and methods contemplated herein not only produce high purity lithium hydroxide, but also allow the production of metallic nickel, cobalt, and electrolytic manganese dioxide (EMD). Preferably, the cobalt and EMD are produced in the same electrolytic cell and the nickel in another, but two or more salt decomposers produce lithium hydroxide with different sulfate contents, thereby enabling a high purity lithium hydroxide product and a lithium recycle stream for pH control and / or leaching. As will be readily understood, the salt decomposers also provide an acid solution that is then used in the leaching circuit to close the loop in the process.

[0020] Thus, from a different perspective, the contemplated systems and processes herein are incorporated into a single electrolytic plating of cobalt and manganese dioxide, recycling the acid and base (lithium hydroxide) within the process of plating non-lithium source metals (cobalt and nickel), thereby avoiding the formation of mixed hydroxides and minimizing costs and raw material requirements. Most typically, a two- or three-stage salt decomposition cell arrangement is used. Furthermore, it should be recognized that the contemplated systems and processes can be easily adapted to black masses containing little or no lithium by using sodium hydroxide, potassium hydroxide, ammonium hydroxide, and / or calcium hydroxide instead of lithium hydroxide.

[0021] For example, referring to FIG. 1, an exemplary overall process 100 can be carried out in which electrode active material ("black mass") 102 is used as the feedstock. In most cases, black mass is obtained from shredded used lithium batteries and typically contains significant amounts of cobalt, nickel, copper, lithium, manganese, aluminum, and graphite. However, as discussed above, it should be recognized that black mass from which at least some (e.g., at least 50%, or at least 70%, or at least 80%, or at least 90%) of the lithium has been removed is also considered a suitable starting material. Furthermore, it is preferred that the black mass has already been processed to remove plastic components, although further or additional plastic removal is also contemplated. Although not limited to the subject matter of the present invention, it is also preferred that the black mass is (or is dried) with a residual moisture content of 5% by weight or less, or 4% by weight or less, or 3% by weight or less, or 2% by weight or less, or 1% by weight or less.

[0022] With further reference to FIG. 1, the dried / dried black mass is fed to a leaching tank 110 where the black mass is slurried with a leaching solution. Most preferably, the leaching solution is sulfuric acid, methanesulfonic acid (MSA), hydrochloric acid, or the like, or a combination thereof, and may include disodium EDTA. The concentration of the acid is typically 0.5M-6M, with the particular concentration being at least in part a function of the particular acid used. For example, the preferred range for sulfuric acid is 1.5M-2.5M due to the solubility limitations of Li2SO4 (about 3.2M) and Co (about 2.4M). On the other hand, when using MSA, the preferred range is 4M-6M, since MSA is monobasic and lithium methanesulfonate is significantly more soluble than Li2SO4. Generally, sulfuric acid, methanesulfonic acid, and disodium EDTA are the preferred leaching agents. In some embodiments, methanesulfonic acid and (possibly) disodium EDTA may be used as the leaching agents.

[0023] In at least some embodiments, an additional reducing agent (e.g., iron(II) sulfate, hydrogen peroxide, etc.) may be used to reduce the Co 3+ Co 2+ , Mn 4+ Mn 2+ It is also noted that the pulp density of the leachate is preferably between 5 and 300 g / L. Regardless of the particular acid and feedstock used in leaching, it is contemplated that the leachate will be concentrated in metal ions and have a final pH between 1 and 5. If the pH is closer to 5, it is contemplated that such a pH can be achieved in a two-stage leaching by mixing the leachate from the second stage with the influent and using the influent as a pH adjuster to bring the pH to about 5.

[0024] In some embodiments, elevated temperatures of 60°C to 90°C may be used during leaching, while in other embodiments, temperatures may be between 10°C to 25°C, or between 20°C to 35°C, or between 30°C to 60°C. Leaching is typically carried out in a batch process with leaching times of about 5 minutes to 1 hour, or between 1 hour to 3 hours, or between 2 hours to 6 hours, or between 6 hours to 12 hours, or even longer. Upon completion of leaching, the slurry from the leaching tank is typically filtered in a filtration unit 115 and the undissolved residue 117 (predominantly graphite or anode material with trace amounts of undissolved metal cations) is removed as a filter cake. If desired, a secondary leaching circuit (not shown) can be added to increase recovery and produce a graphite product with lower metal content.

[0025] In at least some embodiments, the resulting rich leach solution 116 is then fed to a copper recovery cell 120 where the copper is preferentially plated as metallic copper 122 and the iron is preferentially plated as Fe 3+ From Fe 2+ Most typically, the copper recovery cell 120 is configured as an electropolishing reactor with a high surface area cathode (e.g., using graphite felt as a flow-through cathode) where the electrode potential is controlled to preferentially reduce copper. An exemplary configuration of such a polishing reactor suitable for use herein is described in U.S. Patent Application Publication No. 2022 / 0275527, the contents of which are incorporated herein by reference. As will be readily understood, the polishing reactor is operated at a low current sufficient to remove most of the copper present in the leachate without plating significant amounts of other plateable metals such as cobalt or nickel. Additionally, while a flow-through cathode with graphite felt is contemplated above, it should be recognized that a variety of other cathode materials, including stainless steel or titanium, are also believed to be suitable for use herein.

[0026] Upon electrolytic copper removal, a portion of the leach solution 124 so treated is returned to the leach tank 110 where it is treated with Fe 2+ Co3+ Co 2+ and Mn 4+ Mn 2+ to solution. In some embodiments, the portion of the treated leach solution that is returned to the leach tank is between 5% and 98%, while in other embodiments, the portion returned is between 6% and 20%. The other portion of the thus treated leach solution 124 is sent to a precipitation stage 130, where a LiOH stream 174' is added to raise the pH of the system to a value between 3 and 5, thereby precipitating impurities such as aluminum and iron in the form of corresponding aluminum and iron hydroxides 132, without precipitating significant amounts of nickel, cobalt, manganese, and / or lithium (e.g., between 3% and 5%, or between 5% and 10%, or between 10% and 15%, or between 15% and 20%, or between 20% and 30% of the total metal content). The aluminum and iron hydroxide precipitates 132 are then removed via a filtration system and may be sold or disposed of. Most preferably, the LiOH solution 174' used to adjust the pH is obtained from a downstream salt splitter, as described in more detail below.

[0027] After electrolytic removal of copper (by formation of metallic copper) and aluminum and iron (by precipitation), such further treated leach solution 134 is then fed to a metal separation stage. In at least some embodiments, the metal separation stage includes one or more solvent extraction stages in which metal ions are selectively extracted by organic reagents. For example, the first solvent extraction stage 140 includes a solvent extraction system in which cobalt 142B and manganese 142A are removed from the further treated leach solution 134. Among other options, suitable organic solvents include Cyanex 272 and / or equivalent organic solvents. Most typically, the solvent is diluted in an organic diluent (e.g., kerosene, heptane, ethanol, butane). As will be readily appreciated, an appropriate pH during solvent extraction enhances the extraction efficiency and selectivity of cobalt and manganese, and in at least some embodiments, the pH is adjusted using the addition of LiOH or sulfuric acid solutions obtained from a downstream salt decomposition step, as described in more detail below. Of course, it should be recognized that the solvent extraction may be carried out in one or multiple stages to achieve the required extraction efficiency and selectivity.

[0028] The cobalt-manganese-bearing organic phase so formed from the first solvent extraction step is then fed to a stripping step where a concentrated (e.g., 1M-6M) acid solution removes the metal ions. For example, H2SO4 may be used at a concentration of 6M or less, while MSA may be used at a concentration of 5M or less. Alternatively, the acid solution may be other acids such as hydrochloric acid, nitric acid, or other inorganic acids. For recovery of metallic cobalt and EMD, the acid stripping solution is fed to a single electrolytic cell 141 or a series of electrolytic cells where the cobalt and manganese compounds are plated (preferably separately) as valuable products. It should therefore be appreciated that metal recovery may be carried out in a single electrolytic cell that plates only cobalt, or to a combined cobalt / EMD electrolytic cell, or to a combination thereof, depending on the composition of the electrolytic cell feed and the cobalt to manganese ratio. In other embodiments, it is also contemplated that nickel (along with EMD) may be recovered using a "multi-metallic cell."

[0029] After passing through the first solvent exchange stage, the cobalt-manganese depleted leach solution may be fed to a second solvent extraction stage 150 where nickel and remaining cobalt are removed by one or more selective organic reagents. Contemplated organic reagents for nickel removal include Cyanex 272, Versatic 10 Acid, Lix-84, D2EPHA, and / or other equivalent organic solvents, among other suitable options. Again, an appropriate pH during solvent extraction enhances the extraction efficiency and selectivity of nickel, and in at least some embodiments, the pH is adjusted using the addition of LiOH or sulfuric acid solutions obtained from a downstream salt cracking step, as described in more detail below.

[0030] The nickel-loaded organic phase so formed from the second solvent extraction stage is then fed to a stripping stage where a concentrated (e.g., 1M-6M) acid solution removes the metal ions. For example, H2SO4 may be used at a concentration of 6M or less, while MSA may be used at a concentration of 5M or less. Alternatively, the acid solution may be other acids such as hydrochloric acid, nitric acid, or other inorganic acids. For recovery of metallic nickel 152, the acid stripping solution is fed to a single electrolytic cell 151 or a series of electrolytic cells where nickel is plated as a valuable product.

[0031] After passing through the (preferably dual) solvent exchange system, the nickel-depleted leach solution is now significantly depleted in metals other than lithium, and the resulting lithium (sulfate or methanesulfonate) rich leach solution is then fed to one or more salt decomposition cells 170 to recover lithium as alkaline LiOH solution 171 / 174 and produce leach acid 172 (e.g., H2SO4 or MSA), which can then be sent to the start of the process. A lithium recovery unit 180 receives a portion of the alkaline LiOH solution 171 / 174 and produces a pure lithium product. If necessary or desired, an ion exchange system 160 can be used upstream of the salt decomposition cell 170 to remove any cationic metal impurities such as Zn, Cu, Fe, Al, Co, Ni, Mn cations (e.g., using a chelating resin or DOWEX 4195 resin). As will be readily appreciated, contemplated systems and methods may employ multiple salt decomposition stages, with two or three stages being specifically contemplated.

[0032] For example, in one embodiment, the salt decomposition occurs in two or three stages, with the first stage producing the highest concentration of lithium hydroxide with the lowest residual sulfate (or methanesulfonate if the leach solution is MSA) concentration. Most preferably, the LiOH solution produced in this salt decomposition unit is removed from the system and further processed to produce lithium value products. For example, the water can be evaporated to produce LiOH or LiOH·H2O products. Alternatively, the LiOH solution can be carbonated with CO2 gas to produce lithium carbonate, or precipitated with soda ash at high temperature to lithium carbonate. As already mentioned, the H2SO4 produced from this first stage is preferably recycled back into the process (either the solvent extraction acid stripping system and / or the leach system).

[0033] The second stage has a lower concentration of lithium species. The LiOH solution produced in the second stage is low concentration and is sent to the first salt decomposition cell to increase the concentration. Since this process requires a larger amount of pure LiOH, two stages are used to produce pure LiOH, but only one stage is used to produce pure H2SO4 (or MSA). However, it should be noted that while 100% of the acid (less bleed) is preferably recycled to the process somewhere, about 66% of the LiOH is also recycled to the process. Therefore, the volumes of these recycle streams must match those used in the leaching and solvent exchange circuits, which ultimately determines the LiOH concentration produced in the salt decomposition cell. In some embodiments of this second stage, the salt decomposition cell is not required.

[0034] The third stage has the lowest concentration of lithium species and the highest concentration of lithium sulfate (or lithium methanesulfonate) in the hydroxide and acid streams. The LiOH solution produced here may have some contaminants and is recycled to the process for pH control. The H2SO4 (or MSA) and lithium sulfate containing effluent from this third stage is recycled to the leaching circuit in the process. The effluent stream from the final salt decomposition cell (i.e., dilute lithium sulfate) can be (a) fully or partially recycled to the H2SO4 or MSA generation chamber of the third stage salt decomposition cell, (b) fully or partially recycled to the LiOH generation chamber of the third stage salt decomposition cell, (c) both (a) and (b), or (d) if impurities build up to a high enough level, a portion of this stream can go to a wastewater treatment system.

[0035] Figure 2 is a more detailed process flow diagram of a treatment plant 200 in which black mass 202 is treated in a leaching stage 210, a selective electrochemical copper removal stage 220, a precipitation stage 230 in which iron and aluminum ions are removed, two solvent exchange stages 240, 250 to remove cobalt, manganese and nickel, as well as an ion exchange stage 260, and three salt splitters. As can be readily seen from Figure 2, the plant is configured to operate in a closed process to receive black mass and produce various metal products in metallic form and lithium in salt form at very high purity.

[0036] In the example of FIG. 2, lithium sulfate (or lithium methanesulfonate) may be provided to the front end of the process from the effluent of the salt decomposition stage via stream 273. Here, the lithium sulfate stream 273 together with recycled sulfuric acid (or MSA) 272 is fed to the leaching stage 210, which may further include an anode-cathode assembly for reducing the copper ions to metallic copper. The rich leach solution 216 may then be filtered in a filtration unit 215 to remove fine particles, in particular graphite products 217. A portion of the rich leach solution 216 is returned to the leaching stage 210, while the remaining rich leach solution is then fed to the precipitation stage 230, where it is mixed with an alkaline recycled lithium hydroxide solution 274' provided from the second (and / or third) stage of the salt decomposition cell 270. Advantageously, such recycling not only preserves the valuable lithium ions, but also eliminates the need for an external base to raise the pH by an amount that results in the precipitation of aluminum and iron ions in the form of the corresponding hydroxides 232. The precipitates so produced can then be removed in a pressurized filter 231 to produce further treated leach solution 234.

[0037] The further treated leach solution 234 is then fed to a (third stage) solvent exchange unit 240 to remove cobalt and manganese 250, and the effluent of the solvent exchange unit 240 is fed to the solvent exchange unit 250 to selectively remove nickel. As can be seen from FIG. 2, a portion of the recycled lithium hydroxide stream 274' may be used in the solvent exchange unit 240, which again serves to preserve lithium in the process and adjust the pH for copper and manganese absorption. Furthermore, it should be appreciated that the pH in the second stage of the solvent exchange unit 240 may be adjusted with sulfuric acid formed in the process, most preferably from the first and / or second salt decomposer. The aqueous phase so enriched in cobalt and manganese may then be fed to one or more Co / EMD electrolyzers 241 to form metallic cobalt and EMD (electrochemical manganese dioxide). It should therefore be appreciated that the processes presented herein advantageously not only allow for the production of high purity lithium salts, but also allow for the production of EMD and metallic cobalt, both important components in lithium ion battery manufacturing.

[0038] Solvent exchange unit 250 receives the aqueous effluent 244 of solvent exchange unit 240 and is used for the absorption and removal of nickel, where the nickel is removed via a selective solvent and finally plated in electrolytic cell 251 to form metallic nickel 252. It should be appreciated that the aqueous effluent 254 of solvent exchange unit 250 is now enriched in lithium ions and depleted in copper, iron, aluminum, cobalt, manganese, and nickel. Any remaining metal ions (other than lithium) can then be removed from the aqueous effluent 254 of solvent exchange unit 250 in an optional downstream ion exchange unit 260 (here comprising three series-connected ion exchange beds that may have the same or different selectivities). After removing the non-lithium impurities in ion exchange unit 260, the lithium-rich solution (typically containing lithium sulfate or lithium methanesulfonate) is fed to salt decomposition cell 270 (here three series-connected cells), which then produces sulfuric acid, lithium hydroxide, and effluent.

[0039] In the example of Figure 2, the first salt decomposition cell 270A produces a concentrated pure sulfuric acid stream and a concentrated high purity lithium hydroxide stream 271. As will be readily understood, the concentrated sulfuric acid is suitable for recycle within the processes presented herein, and among other options, the sulfuric acid is used as an acidifying reagent for the solvent exchange process and / or an electrolyte for the cobalt / EMD electrolytic cell. The concentrated lithium hydroxide stream of the first salt decomposition cell 270A can then be used in a lithium recovery unit 280 (which may be configured as a crystallizer) to produce a final lithium salt product 282.

[0040] The effluent of the first salt decomposition cell 270A is then fed to a second salt decomposition cell 270B, which again produces a low-purity and low-concentration sulfuric acid stream 272, which is recycled back to the front end of the process as a leaching solution. The lithium hydroxide from the first salt decomposition cell can be returned upstream of the first salt decomposition cell, as exemplarily shown in FIG. 2. The effluent of the second salt decomposition cell 270B is fed to a third salt decomposition cell 270C, which produces another sulfuric acid stream (preferably returned to the second salt decomposition cell) and a lower-purity lithium hydroxide stream 274' that can be recycled back to the process (preferably to the solvent exchange unit and / or precipitation stage as a pH adjuster) to minimize lithium losses. Finally, the effluent 273 of the third salt decomposition cell 270C can be returned to the leaching unit or disposed of as a metal-depleted waste stream.

[0041] In some embodiments, the numbers expressing properties such as amounts of ingredients, concentrations, reaction conditions, etc., used to describe and claim certain embodiments of the present invention should be understood as being modified in some cases by the term "about". Thus, in some embodiments, the numerical parameters set forth in the specification and the appended claims are approximations that may vary depending on the desired properties sought to be obtained by a particular embodiment. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of individually referring to each individual value falling within the range. Unless otherwise indicated herein, each individual value is incorporated herein as if it were individually recited herein.

[0042] All methods described herein may be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context. Any and all examples given with respect to specific embodiments herein, or the use of exemplary language (e.g., "such as"), are intended merely to more fully describe the invention and do not otherwise impose limitations on the scope of the invention as claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0043] As used herein and throughout the claims that follow, the meanings of "a," "an," and "the" include the plural unless the context clearly indicates otherwise. Also, as used herein, the meaning of "in" includes "in" and "on," unless the context clearly indicates otherwise. Also, as used herein, the term "coupled to" is intended to include both direct coupling (where the two elements that are coupled to each other are in contact with each other) and indirect coupling (where at least one additional element is disposed between the two elements), unless the context clearly indicates otherwise. Thus, the terms "coupled to" and "coupled with" are used interchangeably.

[0044] It will be apparent to one skilled in the art that many modifications beyond those already described are possible without departing from the inventive concepts herein. Accordingly, the subject matter of the present invention should not be limited except as by the appended claims. Moreover, in interpreting the specification and claims, all terms should be interpreted in the broadest possible sense consistent with the context. In particular, the terms "comprises" and "comprising" should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referred element, component, or step may be present, utilized, or combined with other elements, components, or steps not expressly mentioned. When the specification or claims refer to at least one selected from the group consisting of A, B, C...N, the sentence should be interpreted as requiring only one element from the group, and not A+N, or B+N, etc.

Claims

1. 1. A method for recovering metals from spent lithium batteries in a closed loop process in which an acid leach solution is recycled, comprising the steps of: leaching a plurality of different metals in ionic form from the battery material using the acidic leach solution to produce a rich leach solution; removing a first metal from the rich leach solution by electroplating to produce a treated leach solution; removing a second metal from the treated leach solution by precipitation to produce a further treated leach solution; removing a third metal and optionally a fourth metal from said further treated leach solution by solvent exchange to produce a third metal and optionally a fourth metal depleted leach solution; regenerating at least a portion of the leach solution by treating the third metal or optionally a fourth metal depleted leach solution in a salt decomposition unit to produce a metal hydroxide solution and an effluent, wherein at least a portion of the metal hydroxide solution is used in the step of removing the second metal and / or the step of removing the third metal and optionally a fourth metal, and optionally at least a portion of the effluent is used in the leaching step; The method includes:

2. 10. The method of claim 1, wherein the battery material comprises black mass and the plurality of different metals comprises copper ions, aluminum ions, iron ions, cobalt ions, manganese ions, nickel ions, and lithium ions.

3. 10. The method of claim 1, wherein the battery material comprises black mass, the plurality of different metals comprises copper ions, aluminum ions, iron ions, cobalt ions, manganese ions, and nickel ions, and the black mass is a treated black mass from which lithium ions have previously been removed.

4. The method according to any one of claims 1 to 3, wherein the leach solution is sulphuric acid or methanesulphonic acid, optionally containing a chelating agent.

5. The method of any one of claims 1 to 4, wherein the first metal is copper and electroplating comprises preferential electroplating of copper onto a cathode.

6. The method of claim 5 , wherein the second metal is aluminum and / or iron.

7. The method of claim 6 , wherein the third metal is cobalt and / or manganese.

8. 8. The method of claim 7, wherein the cobalt and / or the manganese are recovered from the organic solvent of the solvent exchange using an acid, and the copper and / or the manganese are plated as metallic copper and as EMD in one electrolytic cell.

9. 8. The method of claim 7, wherein the solvent exchange uses a portion of the regenerated leach solution and / or the metal hydroxide solution from the salt decomposition unit.

10. The method of claim 8 , wherein the acid is recycled in the solvent exchange.

11. 10. The method of claim 1, wherein the optional fourth metal is nickel, and the fourth metal is removed in another solvent exchange.

12. 12. The method of claim 11, wherein the nickel is recovered from the organic solvent of the further solvent exchange using an acid and the nickel is plated as metallic nickel in an electrolytic cell.

13. 12. The method of claim 11, wherein the further solvent exchange uses a portion of the regenerated leach solution and / or the metal hydroxide solution from the salt decomposition unit.

14. 13. The method of claim 12, wherein the acid is recycled in the further solvent exchange.

15. The method of claim 1 , wherein the salt decomposition unit comprises at least two salt decomposition devices.

16. The first portion of the metal hydroxide solution in one of the at least two salt decomposers is LiOH or LiOH.H ２ 16. The method of claim 15, further processed to produce a O product or a lithium carbonate solution or precipitate.

17. The method of claim 15 , wherein a second portion of the metal hydroxide solution is used in the step of removing the second metal.

18. 16. The method of claim 15, wherein a second portion of the metal hydroxide solution is used in the step of removing the third metal and optionally a fourth metal.

19. 2. The method of claim 1, further comprising the step of using an ion exchange or chelating resin to remove metal ion impurities from the third metal and optionally fourth metal depleted leach solution prior to feeding the third metal and optionally fourth metal depleted leach solution to the salt decomposition unit.

20. 10. The method of claim 1, wherein when the battery material is at least partially lithium ion depleted material, the metal hydroxide solution is sodium hydroxide, potassium hydroxide, or calcium hydroxide.

21. The method of claim 1 , wherein the salt decomposition unit is a bipolar electrodialysis unit.

Images