Improved system and method for metal 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 of related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 321,897, filed on 21 March 2022, which is concurrently pending and whose contents are incorporated herein by reference.

[0002] The field of this invention is the field 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 art description contains information that may be useful in understanding the present invention. The background art description does not constitute prior art, or information relating to the claimed invention, or any publication specifically or implicitly referenced herein.

[0004] All publications and patent applications within this specification are invoked by reference to the same extent as any individual publication or patent application is specifically and individually indicated as being invoked by reference. If a definition or use of a term in a cited reference document contradicts or is contrary to a definition of such term provided herein, the definition provided herein shall apply, and the definition in the reference document shall not apply.

[0005] The manufacture and use of lithium-ion batteries have increased dramatically worldwide over the past decade, placing a significant strain on the supply of raw materials needed to produce such batteries. Furthermore, demand is projected to increase even further for at least the next 20 years. Unfortunately, the procurement and processing of raw materials are almost entirely dependent on foreign countries (outside the United States), exposing the U.S. economy to significant supply and price vulnerabilities.

[0006] While lead-acid battery recycling is an essential part of the resupply of lead for the manufacture of new lead-acid batteries, lithium-ion battery recycling is less developed. Among other factors are the relatively diverse form factors (battery packs, modules, cylindrical cells, prismatic cells, pouch cells, etc.), the available materials (defective cells, metal scrap, slurry, and powder, etc.), and the cathode chemicals (lithium cobalt oxide, lithium nickel-cobalt-aluminum oxide, lithium nickel-cobalt-manganese oxide, lithium nickel-cobalt-manganese-aluminum oxide, lithium nickel oxide, and lithium manganese oxide, etc.). Furthermore, the relative amounts of transition metals used in lithium-based batteries vary considerably among lithium-ion batteries, which usually complicates the recovery of lithium and other valuable metals from lithium-ion batteries. In addition, similar supply challenges exist 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 provided elsewhere (see Batteries 2019, 5, 68; doi:10.3390 / batteries5040068).

[0007] Methods for recovering valuable metals and metal salts from lithium battery waste often involve solvent-based processes. For example, U.S. Patent Application Publication 2021 / 0317547 teaches a wet smelting method for recovering metals from used lithium batteries, in which a hydrobromic acid leaching aqueous solution is brought into contact with electrode material to extract the metal. The resulting extract is then subjected to precipitation and / or cathode electrodeposition to obtain the desired metal. In another known method, such as disclosed in U.S. Patent Application Publication 2021 / 0344058, CO2 is used as the leaching solution, and the leaching is then subjected to precipitation and roasting to obtain cobalt and lithium materials. In yet another known method, as taught in U.S. Patent Application Publication 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 cobalt, nickel, and manganese oxides are dissolved using reduction with sulfur dioxide.

[0008] Many such known recovery methods often require further processes to obtain the metal or metal salt with the desired purity and yield. For example, cobalt can be formed by electrolysis in an electrochemical process, such 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. Yet another known method recovers lithium from a leachate treated with an electrodialyzer, as taught in Japanese Patent Publication No. 2012 / 234732. Similarly, lithium hydroxide is prepared from a lithium sulfate solution using an electrodialysis process, as described in International Publication No. 2013 / 159194. Unfortunately, all or almost all of these known processes require complex operations to generate separate product streams, require subsequent treatment of the product streams, and are generally not suitable as closed-loop processes to thus reduce waste streams. Furthermore, many known methods for metal recovery recover the metal in salt form, which requires further processing to obtain the corresponding metal.

[0009] To simplify the operation, a sequential solvent extraction process, such as that described in U.S. Patent Application Publication No. 2022 / 0205064, can be used. While at least conceptually simpler, various difficulties still remain. Among other issues, such sequential solvent extraction generates numerous liquid streams that require complex handling and preparation. Furthermore, in most cases, such sequential solvent stripping does not allow for an integrated process in which the solvent (and especially the leached solution) can be recycled. Moreover, the metal thus recovered is usually formed as a metal salt that requires further processing to the corresponding pure non-lithium metal.

[0010] Therefore, although various systems and methods for recovering metals from lithium batteries are known in the art, all or almost all of them have some drawbacks. Thus, improvements in methods for recovering metals from lithium batteries, particularly lithium, manganese, cobalt, copper, and nickel from black mass, are still needed. [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] The subject of this invention is various plant configurations, systems, and methods for metal recovery from used lithium batteries, in which multiple metals are recovered in high purity in a closed-loop process that enables the recycling of the leaching solvent. Advantageously, the intended systems and methods reduce the total amount of solvent used and the generation of waste streams, while simultaneously enabling a simple and effective process flow. [Means for solving the problem]

[0012] In one aspect of the subject matter of the present invention, the inventors envision a method for recovering metal from a spent lithium battery, comprising the steps of: generating a rich leaching solution by leaching a plurality of different metals in ionic form from battery material with a leaching solution; generating a treated leaching solution by removing a first metal from the rich leaching solution by electroplating; generating a further treated leaching solution by removing a second metal from the rich leaching solution by precipitation; generating a third metal and optionally a fourth metal-deficient leaching solution by removing a third metal and optionally a fourth metal from the further treated leaching solution by solvent exchange; and yet another step of regenerating at least a portion of the leaching solution to generate a metal hydroxide solution and effluent by treating the third metal and optionally a fourth metal-deficient leaching solution in a salt decomposition unit, 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 spilled material is used in the leaching step.

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

[0014] In certain embodiments of the subject matter of the present invention, 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 further embodiments of the subject matter of the present invention, the third metal is cobalt and / or manganese. Preferably, cobalt and / or manganese are recovered from the organic solvent of solvent exchange using an acid, and the cobalt and / or manganese are plated as metallic cobalt and as EMD in one electrolytic cell. Furthermore, an optional fourth metal is nickel, and the fourth metal is intended to be removed in another solvent exchange. Nickel is then plated as metallic nickel in an electrolytic cell. As is readily understood, the solvent exchange uses a portion of the regenerated leaching solution and / or metal hydroxide solution from a salt decomposition unit.

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

[0016] If desired, the intended system may further include an ion exchange resin or a chelating resin to remove metal ion impurities from the third metal and optionally the fourth metal-deficient leaching solution before supplying the third metal and optionally the fourth metal-deficient leaching solution to the salt decomposition unit.

[0017] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings in which like numerals represent like components. [Brief Description of the Drawings]

[0018] [Figure 1] 1 is an exemplary, simplified schematic process flow diagram for metal recovery from black mass in accordance with the inventive subject matter. [Figure 2] 2 is a more detailed, exemplary process flow diagram for metal recovery from black mass in accordance with the inventive subject matter. [Mode for Carrying Out the Invention]

[0019] The present inventors have discovered various systems and methods for recovering metals from lithium batteries, and particularly from 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 recovery of various valuable metals such as copper, cobalt, manganese, nickel, and lithium. Advantageously, the contemplated systems and methods herein not only produce high-purity lithium hydroxide, but also allow for the production of metallic nickel, cobalt, and electrolytic manganese dioxide (EMD). Preferably, cobalt and EMD are produced in the same electrolytic cell, and nickel is produced in a separate electrolytic cell, while two or more salt decomposition units produce lithium hydroxide with different sulfate contents, thereby enabling a high-purity lithium hydroxide product for pH control and / or leaching and a lithium recycle stream. As will be readily appreciated, the salt decomposition unit also provides an acidic solution, which is then used in the leaching circuit to close the loop in the process.

[0020] Therefore, from a different perspective, the systems and processes envisioned herein are incorporated into a single electroplating of cobalt and manganese dioxide, recycling acids and bases (lithium hydroxide) within the process of plating non-lithium raw material metals (cobalt and nickel), thereby avoiding the formation of mixed hydroxides and minimizing cost and raw material requirements. Most typically, a two- or three-stage salt-cracked cell configuration is used. Furthermore, it should be recognized that the envisioned systems and processes can be easily adapted to black mass containing little to no lithium by using sodium hydroxide, potassium hydroxide, ammonium hydroxide, and / or calcium hydroxide instead of lithium hydroxide.

[0021] For example, referring to Figure 1, an exemplary whole process 100 may be carried out in which electrode active material ("black mass") 102 is used as a feedstock. In most cases, the black mass is obtained from shredded spent lithium batteries and typically contains significant amounts of cobalt, nickel, copper, lithium, manganese, aluminum, and graphite. However, as mentioned 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 lithium has been removed is also considered a suitable starting material. Furthermore, although the black mass is preferably already treated to remove plastic components, further or additional plastic removal is also intended. Although not limited to the subject matter of the present invention, the black mass is also preferably dried (or to be dried) with a residual water 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 Figure 1, the dried black mass is supplied 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, etc., or a combination thereof, and may comprise disodium EDTA. The acid concentration is typically 0.5M to 6M, with the specific concentration being at least partially a function of the particular acid used. For example, the preferred range for sulfuric acid is 1.5M to 2.5M due to the solubility limits of Li₂SO₄ (about 3.2M) and Co (about 2.4M). On the other hand, when MSA is used, the preferred range is 4M to 6M, as MSA is monobasic and lithium methanesulfonate is significantly more soluble than Li₂SO₄. In general, sulfuric acid, methanesulfonic acid and disodium EDTA are preferred leaching agents. In some embodiments, methanesulfonic acid and (possibly) disodium EDTA may be used as the leaching agent.

[0023] In at least some embodiments, additional reducing agents (e.g., iron(II) sulfate, hydrogen peroxide, etc.) are used to reduce Co 3+ to Co 2+ , and Mn 4+ to Mn 2+ into the solution. It is further contemplated that the pulp density of the leachate is preferably 5 to 300 g / L. Regardless of the specific acid and feedstock used for leaching, it is contemplated that the leachate is enriched in metal ions and has a final pH of 1 to 5. Where the pH is close to 5, it is contemplated that such a pH can be achieved in a two-stage leaching process by mixing the leachate from the second stage with the incoming feed material, and using the incoming feed material as a pH adjuster to reach a pH of about 5.

[0024] In some embodiments, high temperatures of 60°C to 90°C may be used during leaching, while in other embodiments, the temperature may be 10°C to 25°C, or 20°C to 35°C, or 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 1 hour to 3 hours, or 2 hours to 6 hours, or 6 hours to 12 hours, or even longer. Once leaching is complete, the slurry from the leaching tank is typically filtered through a filtration unit 115, and the insoluble residue 117 (mainly graphite or anode material containing trace amounts of insoluble metal cations) is removed as a filter cake. If desired, a secondary leaching circuit (not shown) may be added to increase the recovery rate and produce a graphite product with a lower metal content.

[0025] In at least some embodiments, the rich leaching solution 116 thus obtained is then supplied to a copper recovery cell 120, where the copper is preferentially plated as metallic copper 122, and the iron is Fe 3+ From Fe 2+ It is preferentially oxidized to . Most typically, the copper recovery cell 120 is configured as an electropolishing reactor having 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 is readily apparent, the polishing reactor is operated with a current low enough to remove most of the copper present in the leaching solution without plating any other significant amounts of plateable metals such as cobalt or nickel. Furthermore, while a flow-through cathode having graphite felt is intended above, it should be recognized that a variety of other cathode materials, including stainless steel or titanium, are also considered suitable for use herein.

[0026] During the electrolytic copper removal process, a portion of the treated leaching solution 124 returns to the leaching tank 110, where Fe 2+ Co3+ Co 2+ reduction to, and Mn 4+ Mn 2+ reduction to, aiding them into a solution. In some embodiments, the portion of the treated leach solution returned to the leaching tank is 5% to 98%, while in other embodiments, the returned portion is 6% to 20%. The remaining portion of the leach solution 124 treated in this way is sent to the precipitation stage 130, where a LiOH stream 174' is added to raise the pH of the system to a value of 3 to 5, thereby precipitating impurities such as aluminum and iron in the form of corresponding aluminum hydroxide and iron hydroxide 132, without precipitating significant amounts (for example, 3% to 5%, or 5% to 10%, or 10% to 15%, or 15% to 20%, or 20% to 30% of the total metal content) of nickel, cobalt, manganese, and / or lithium. The aluminum and iron hydroxide precipitate 132 is then removed via a filtration system, and can be sold or disposed of. Most preferably, the LiOH solution 174' used to adjust the pH is obtained from a downstream salt decomposer, as described in more detail below.

[0027] After electrolytic removal of copper (by the formation of metallic copper) and aluminum and iron (by precipitation), the thus further treated leached solution 134 is then supplied to a metal separation step. In at least some embodiments, the metal separation step includes one or more solvent extraction steps in which metal ions are selectively extracted by organic reagents. For example, a first solvent extraction step 140 includes a solvent extraction system in which cobalt 142B and manganese 142A are removed from the further treated leached solution 134. Among other options, particularly 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 is readily apparent, a suitable 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 a LiOH solution or sulfuric acid solution obtained from a downstream salt decomposition step, as will be described in more detail below. Naturally, it should be recognized that solvent extraction can be carried out in one or multiple steps to achieve the required extraction efficiency and selectivity.

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

[0029] After passing through the first solvent exchange step, the cobalt-manganese deficient leaching solution may be supplied to a second solvent extraction step 150, where nickel and the remaining cobalt are removed by one or more selective organic reagents. Among other suitable options, organic reagents intended for nickel removal include Cyanex 272, Versatic 10 Acid, Lix-84, D2EPHA, and / or other equivalent organic solvents. Here 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 a LiOH solution or sulfuric acid solution obtained from a downstream salt decomposition step, as will be described in more detail below.

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

[0031] After passing through a (preferably double) solvent exchange system, the nickel-deficient leaching solution, where metals other than lithium are significantly deficient, is then fed to one or more salt-decomposing cells 170 to recover lithium as alkaline LiOH solutions 171 / 174 and to produce leaching acids 172 (e.g., H2SO4 or MSA), which can then be sent to the process initiation point. A lithium recovery unit 180 receives a portion of the alkaline LiOH solutions 171 / 174 to produce a pure lithium product. If necessary or desired, an ion exchange system 160 can be used upstream of the salt-decomposing cells 170 to remove any cationic metal impurities such as Zn cations, Cu cations, Fe cations, Al cations, Co cations, Ni cations, Mn cations (e.g., using chelate resin or DOWEX 4195 resin). For ease of understanding, the intended system and method may employ multiple salt-grown steps, with two or three steps being particularly intended.

[0032] For example, in one embodiment, salt decomposition occurs in two or three stages, the first stage producing the highest concentration of lithium hydroxide at the lowest residual sulfate (or methanesulfonate, if the leaching solution is MSA) concentration. Most preferably, the LiOH solution produced in this salt decomposition apparatus is removed from the system and further processed to produce lithium valuable products. For example, 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 produce lithium carbonate. As already mentioned, the H2SO4 produced from this first stage is preferably returned to the process (either a solvent extraction acid stripping system and / or a leaching system) for recycling.

[0033] The second stage has a lower concentration of lithium species. The LiOH solution produced in the second stage is of a lower concentration and is sent to the first salt-decomposition cell to increase its concentration. Since this process requires a larger amount of pure LiOH, two stages are used for the production of pure LiOH, but only one stage is used for the production of pure H2SO4 (or MSA). However, it should be noted that 100% of the acid (less bleed) is preferably recycled to some process, but about 66% of the LiOH is also recycled to the process. Therefore, the volume of these recycled streams must match those used in the leaching and solvent exchange circuits, which ultimately determines the concentration of LiOH 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 and highest concentrations of lithium species and lithium sulfate (or lithium methanesulfonate) in the hydroxide and acid streams. The LiOH solution produced here may contain some contaminants and is recycled to a process for pH control. The H2SO4 (or MSA) and lithium sulfate-containing effluent from this third stage is recycled to the leaching circuit in this process. The effluent from the final salt cracking cell (i.e., diluted lithium sulfate) may (a) be completely or partially recycled to the H2SO4 production chamber or MSA production chamber of the third stage salt cracking cell, (b) be completely or partially recycled to the LiOH production chamber of the third stage salt cracking cell, (c) be both (a) and (b), or (d) if impurities accumulate to sufficiently high levels, a portion of this flow may proceed to a wastewater treatment system.

[0035] Figure 2 is a more detailed process flow diagram of the processing plant 200, in which the black mass 202 is processed 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 and 250 for the removal of cobalt, manganese and nickel, as well as an ion exchange stage 260, and three salt crackers. As can be seen immediately from Figure 2, the plant is configured to receive the black mass and operate in a closed process that produces various metallic products in metallic form and lithium in salt form with very high purity.

[0036] In the example in Figure 2, lithium sulfate (or lithium methanesulfonate) may be supplied to the process front end from the effluent of the salt cracking stage via flow 273. Here, the lithium sulfate flow 273, along with recycled sulfuric acid (or MSA) 272, is fed to the leaching stage 210, which may further include an anode-cathode assembly for reducing copper ions to metallic copper. The rich leaching solution 216 is then filtered in a filtration unit 215 to remove particulate matter, particularly graphite products 217. A portion of the rich leaching solution 216 is returned to the leaching stage 210, while the remaining rich leaching solution is then fed to the precipitation stage 230, where this solution is mixed with an alkaline recycled lithium hydroxide solution 274' provided from the second (and / or third) stage of the salt cracking cell 270. Advantageously, such recycling not only preserves valuable lithium ions but also eliminates the need for an external base to raise the pH in amounts that result in the precipitation of aluminum and iron ions in the form of the corresponding hydroxide 232. The precipitate thus produced can then be removed in a pressure filter 231 to produce a further treated leachate 234.

[0037] Further treated leaching solution 234 is then supplied to (third stage) solvent exchange unit 240 to remove cobalt and manganese 250, and the effluent from solvent exchange unit 240 is supplied to solvent exchange unit 250 to selectively remove nickel. As can be seen from Figure 2, a portion of the recycled lithium hydroxide stream 274' may also be used within solvent exchange unit 240, which helps to reconserve lithium in the process and adjust the pH for copper and manganese absorption. Furthermore, it should be noted that the pH in the second stage of solvent exchange unit 240 can be adjusted with sulfuric acid formed in the process, most preferably from the first and / or second salt decomposition units. The aqueous phase, thus concentrated with cobalt and manganese, can then be supplied to one or more Co / EMD electrolytic cells 241 to form metallic cobalt and EMD (electrochemical manganese dioxide). Therefore, it should be recognized that the processes presented herein are advantageous not only in enabling the production of high-purity lithium salts, but also in enabling the production of EMD and metallic cobalt, which are both important components in lithium-ion battery manufacturing.

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

[0039] In the example shown in 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 is readily apparent, the concentrated sulfuric acid is suitable for recycling within the processes presented herein, and among other options, sulfuric acid is used in particular as an acidifying reagent for solvent exchange processes and / or as an electrolyte for cobalt / EMD electrolytic cells. The concentrated lithium hydroxide stream from 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 the final lithium salt product 282.

[0040] The effluent from the first salt-decomposing cell 270A is then fed to the second salt-decomposing cell 270B, which again generates a low-purity, low-concentration sulfuric acid stream 272, which is recycled back to the front end of the process as a leachate. The lithium hydroxide from the first salt-decomposing cell may be returned to the upstream side of the first salt-decomposing cell, as illustrated in Figure 2. The effluent from the second salt-decomposing cell 270B is fed to the third salt-decomposing cell 270C, which generates another sulfuric acid stream (preferably returned to the second salt-decomposing cell) and a lower-purity lithium hydroxide stream 274', which can be recycled back to the process (preferably to the precipitation stage as a solvent exchange unit and / or pH adjuster) to minimize lithium loss. Finally, the effluent 273 from the third salt-decomposing cell 270C may be returned to the leachate unit or discarded as a metal-deficient waste stream.

[0041] In some embodiments, numerical values ​​representing characteristics such as the quantity, concentration, and reaction conditions of the components used to describe and assert specific embodiments of the present invention should be understood, in some cases, modified by the term “about.” Thus, in some embodiments, the numerical parameters described in the specification and appended claims are approximations that may vary depending on the desired characteristics to be obtained by the particular embodiment. The enumeration of value ranges herein is intended merely as a concise way of referring to individual values ​​within that range. Unless otherwise indicated herein, individual values ​​are incorporated herein as if they were individually enumerated herein.

[0042] All methods described herein may be carried out in any suitable order, unless otherwise indicated herein or unless it is clearly inconsistent with the context. Any and all examples or exemplary words (e.g., “like”) given in reference to specific embodiments herein are intended merely to better illustrate the invention and not to limit the scope of the invention as otherwise claimed. No words herein should be construed as indicating any non-claimed element essential to the carrying out of the invention.

[0043] In the descriptions herein and throughout the following claims, the meanings of “a,” “an,” and “the” include the plural unless the context clearly indicates otherwise. Also, in the descriptions herein, the meaning of “in” includes “in” and “on” unless the context clearly indicates otherwise. Furthermore, in the descriptions herein, the term “to be joined to” includes both direct joining (two elements joined to each other are in contact with each other) and indirect joining (at least one additional element is placed between the two elements). Thus, the terms “to be joined to” and “to be joined with” are used synonymously.

[0044] Those skilled in the art will see that many modifications beyond those already described are possible without departing from the inventive concept set forth herein. Therefore, the subject matter of the present invention should not be limited beyond the appended claims. Furthermore, 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 non-exclusively as referring to an element, component, or step, indicating that the element, component, or step mentioned exists, is utilized, or can be combined with other elements, components, or steps not explicitly mentioned. Where this specification or the claims refer to at least one selected from the group consisting of A, B, C…N, this statement should be interpreted as requiring only one element from this group, and not A+N, B+N, etc.

Claims

1. A method for recovering metal from a used lithium battery in a closed-loop process in which a leaching solution is recycled, A step of generating a rich leaching solution by leaching multiple different metals in ionic form from a battery material using the aforementioned leaching solution, The steps include: the plurality of different metals include copper, aluminum, iron, cobalt, manganese, nickel, and lithium; A step of producing a treated leaching solution by removing copper as the first metal from the rich leaching solution by electroplating, A step of generating a further treated leached solution by removing aluminum and / or iron as a second metal from the treated leached solution by precipitation, A step of producing (1) a third metal and optionally a fourth metal-deficient leaching solution and (2) an aqueous phase concentrated with cobalt and / or manganese, by solvent exchange, from the further treated leaching solution, wherein cobalt and / or manganese are removed as a third metal and nickel is optionally removed as a fourth metal, The steps include supplying the aqueous phase, which is concentrated with cobalt and / or manganese and produced by the solvent exchange, to an electrolytic cell that produces metallic cobalt and electrolytic manganese dioxide (EMD), A step of generating a lithium hydroxide solution and effluent by treating the third metal or optionally a fourth metal-deficient leaching solution in a salt decomposition unit, thereby regenerating at least a portion of the leaching solution, wherein at least a portion of the lithium hydroxide solution is used in the step of removing the second metal and / or the third metal and optionally a fourth metal, and optionally at least a portion of the effluent is used in the step of generating the rich leaching solution. A method that includes this.

2. The method according to claim 1, wherein the battery material includes black mass.

3. The method according to claim 2, wherein the black mass is treated black mass from which lithium ions have been removed in advance.

4. The method according to claim 1, wherein the leaching solution is sulfuric acid or methanesulfonic acid and optionally contains a chelating agent.

5. The method according to claim 1, wherein the electroplating comprises selective electrochemical removal of copper from the cathode.

6. The method according to claim 1, wherein the second metal is aluminum.

7. The method according to claim 1, wherein the third metal is cobalt.

8. The method according to claim 1, wherein the cobalt and / or manganese are recovered from the solvent-exchanged organic solvent using an acid, and the cobalt and / or manganese are plated as metallic cobalt and as EMD in one electrolytic cell.

9. The method according to claim 7, wherein the solvent exchange is performed using a portion of the regenerated leaching solution and / or lithium hydroxide solution from the salt decomposition unit.

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

11. The method according to claim 1, wherein the optional fourth metal is removed by another solvent exchange.

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

13. The method according to claim 11, wherein the other solvent exchange uses a portion of the regenerated leaching solution and / or lithium hydroxide solution from the salt decomposition unit.

14. The method according to claim 12, wherein the acid is recycled in the other solvent exchange.

15. The method according to claim 1, wherein the salt decomposition unit includes at least two salt decomposition devices.

16. The first fraction of the lithium hydroxide solution produced in one of the at least two salt decomposition devices is LiOH or LiOH·H ２ The method according to claim 15, further processed to produce an O product or a lithium carbonate solution or lithium carbonate precipitate.

17. The method according to claim 15, wherein a second fraction of the lithium hydroxide solution produced in one of the at least two salt decomposition devices is used in the step of removing the second metal.

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

19. The method according to claim 1, further comprising the step of using an ion exchange resin or a chelating resin to remove metal ion impurities from the third metal and optionally the fourth metal-deficient leaching solution before supplying the third metal and optionally the fourth metal-deficient leaching solution to the salt decomposition unit.

20. The method according to claim 1, wherein if the used lithium battery is at least partially deficient in lithium ions, the lithium hydroxide solution further comprises sodium hydroxide, potassium hydroxide, or calcium hydroxide.

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

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