Improved system and method for metal recovery from lithium ion batteries

Abstract

Black materials from waste lithium batteries are leached for recovery of various metals in processes including precipitation, solvent exchange, ion exchange, and salt separation, thereby producing a variety of product streams for recovery of pure valuable products. Most typically, the process is a closed loop process, and metallic cobalt and metallic nickel, EMD, and a high purity lithium hydroxide or lithium carbonate product can be produced with minimal production of the waste stream.

Description

[0001] This application claims priority to co-pending U.S. provisional patent application serial number 63 / 321,897 filed on March 21, 2022, which is incorporated herein by reference. Technical Field

[0002] The field of the invention is the recovery of metals from lithium batteries and in particular relates to the recovery of lithium, cobalt, copper, manganese and nickel from ferrous materials. Background of the Invention

[0004] The Background Description includes information that may be useful in understanding the present invention. No admission is made that any of the information provided herein is prior art or relevant to the presently claimed invention, nor is an admission made that any publication specifically or implicitly referenced is prior art.

[0005] All publications and patent applications are incorporated herein by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. To the extent that a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

[0006] Over the past decade, the production and use of lithium-ion batteries has increased dramatically around the world, which has put tremendous pressure on the supply of raw materials used to manufacture such batteries. Moreover, demand is expected to increase further for at least the next two decades. Unfortunately, raw material sourcing and processing is almost entirely based in foreign (non-U.S.) countries, which exposes the U.S. economy to severe supply vulnerabilities and price vulnerabilities.

[0007] While the recycling of lead-acid batteries has become an essential part of resupplying lead for the production of new lead-acid batteries, the recycling of lithium-ion batteries has not been well developed. Among many factors, there is a relatively large diversity in form factors (such as battery packs, modules, cylindrical cells, square cells, soft-pack cells, etc.), available materials (such as defective batteries, metal fragments, metal slurries and metal powders), and positive electrode chemistries (such as lithiated cobalt oxides, lithiated nickel-cobalt-aluminum oxides, lithiated nickel-cobalt-manganese oxides, lithiated nickel-cobalt-manganese-aluminum oxides, lithiated nickel-oxides, and lithiated manganese-oxides, etc.). In addition, the relative amounts of transition metals used in lithium-based batteries are substantially different in different lithium-ion batteries, which generally makes it difficult to recover lithium and other valuable metals from lithium-ion batteries. In addition, valuable metals such as nickel, cobalt and manganese also face similar supply challenges, and many lithium recovery methods are completely unable to address the recycling of these elements. A review of currently known lithium-ion battery processing methods can be found elsewhere (see Batteries 2019, 5, 68; doi:10.3390 / batteries5040068).

[0008] Among the various methods for recovering valuable metals and metal salts from lithium battery waste materials, solvent-based methods are often used. For example, US2021 / 0317547 teaches a hydrometallurgical method for recovering metals from failed lithium batteries, in which an aqueous solution of hydrobromic acid is used as a leaching liquid to contact an electrode material to extract the metal. The extract thus obtained is then subjected to precipitation and / or cathode electrodeposition to obtain the metal of interest. In another known method, as disclosed in US2021 / 0344058, CO is used. 2 As a leaching solution, the leached solution is then precipitated and roasted to produce cobalt and lithium materials. In other known methods, as taught in US2022 / 0009793, metal sulfates are obtained from the mother liquor for further processing. Similarly, US2022 / 0013815 teaches the use of sulfuric acid as a leaching fluid, in which cobalt oxides, nickel oxides and manganese oxides are dissolved by the reduction of gaseous sulfur dioxide.

[0009] In many of these known recovery methods, additional processing is usually required to obtain the metal or metal salt of 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. In other known methods, lithium is recovered from a leachate treated with an electrodialyzer as taught in JP 2012 / 234732. Similarly, lithium hydroxide is prepared from a lithium sulfate solution using an electrodialysis method as described in WO 2013 / 159194. Unfortunately, all or almost all of these known methods require complex operations to generate different product streams, require subsequent processing of the product streams, and are generally not suitable for closed-loop processes to reduce waste streams. In addition, a large number of known metal recovery methods will recover metals in the form of salts, which need to be further processed into the corresponding metals.

[0010] To simplify the operation, a sequential solvent extraction method as described in US2022 / 0205064 can be used. Although at least conceptually simpler, various difficulties still exist. Among many problems, such sequential solvent extraction generates a large number of liquid streams that require complex processing and coordination. In addition, in most cases, such sequential solvent stripping cannot be used for the entire process that can recycle the solvent (especially the leachate). In addition, the metal recovered in this way is usually formed in the form of a metal salt that needs to be further processed into the corresponding pure non-lithium metal.

[0011] Thus, although a variety of systems and methods for recovering metals from lithium batteries are known in the art, all or nearly all of these systems and methods have several disadvantages. Thus, there remains a need for improved methods for recovering metals from lithium batteries, particularly lithium, manganese, cobalt, copper and nickel from ferrous materials. Summary of the invention

[0012] The present subject matter relates to various apparatus configurations, systems and methods for recovering metals from waste lithium batteries, wherein various metals are recovered at high purity in a closed loop process that allows for the recycling of leaching solvents. Advantageously, the contemplated systems and methods will reduce overall solvent usage and generation of waste streams while enabling a simple and efficient process flow.

[0013] In one aspect of the inventive subject matter, the inventors contemplate a method for recovering metals from spent lithium batteries, the method comprising the step of leaching a plurality of different metals in ionic form from a battery material using a leachate to thereby produce a pregnant leachate, another step of removing a first metal from the pregnant leachate by electroplating to produce a treated leachate, a further step of removing a second metal from the pregnant leachate by precipitation to produce a further treated leachate, a still further step of removing a third metal and optionally a fourth metal from the further treated leachate by solvent exchange to produce a third metal and optionally a fourth metal depleted leachate, and a further step of treating the third metal and optionally a fourth metal depleted leachate in a salt separator unit to regenerate at least some of the leachate to produce a metal hydroxide solution and an effluent, wherein at least some 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 the fourth metal. Optionally, at least some of the effluent is used in the leaching step.

[0014] In some embodiments, the battery material includes a black substance and a plurality of different metals, including lithium ions, and also copper ions, aluminum ions, iron ions, cobalt ions, manganese ions and / or nickel ions. In other embodiments, the battery material includes a treated black substance from which lithium ions have been previously removed. In this case, the metal hydroxide solution is sodium hydroxide, potassium hydroxide or calcium hydroxide. Most typically, the leachate is sulfuric acid or methanesulfonic acid, and may also contain a chelating agent (e.g., EDTA).

[0015] In certain aspects of the inventive subject matter, the first metal is copper, and the electroplating of copper will generally preferentially electroplate copper onto a circulating cathode (e.g., graphite felt) and / or a solid cathode (e.g., stainless steel or titanium), and / or the second metal will be aluminum and / or iron. In other aspects of the inventive subject matter, the third metal is cobalt and / or manganese. Preferably, cobalt and / or manganese are recovered from an organic solvent in a solvent exchange using an acid, and cobalt and / or manganese will be plated as metallic cobalt and EMD in a single electrolytic cell. In addition, it is envisioned that the optional fourth metal is nickel, and the fourth metal is removed in a separate solvent exchange. The nickel is then plated as metallic nickel in the electrolytic cell. It is readily understood that the solvent exchange uses a portion of the regenerated leachate and / or metal hydroxide solution from the salt separator unit.

[0016] In yet another aspect of the inventive subject matter, the salt separator unit will include at least two salt separators. In a typical embodiment, the first portion of the metal hydroxide solution from one of the at least two salt separators is further processed to produce LiOH or LiOH·H 2The second part of the product or lithium carbonate solution or lithium carbonate precipitate, and / or the metal hydroxide solution is used for the leaching step, and / or the step of removing the second metal. The second part of the metal hydroxide solution can also be used for the step of removing the third metal and the optional fourth metal.

[0017] If desired, the contemplated system may also include ion exchange resins or chelating resins to remove metal ion impurities from the third metal and optional fourth metal depleted leachate prior to feeding the third metal and optional fourth metal depleted leachate to the salt separator unit.

[0018] Various objects, features, aspects, and advantages of the present subject matter will become more apparent from the following detailed description of preferred embodiments and the accompanying drawings, in which like numerals represent like components. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is an exemplary and simplified schematic process flow diagram for recovering metals from ferrous materials in accordance with the present subject matter.

[0020] Figure 2 is a more detailed exemplary process flow diagram for recovering metals from ferrous materials in accordance with the present subject matter.

[0021] Detailed description

[0022] The inventors have found a variety of systems and methods for recovering metals from lithium batteries, particularly from the black matter of lithium batteries, wherein the leachate is subjected to a closed-loop process using precipitation, solvent extraction and salt separation to recover various valuable metals such as copper, cobalt, manganese, nickel and lithium. Advantageously, the envisioned system and method proposed herein will not only generate high-purity lithium hydroxide, but also metallic nickel, metallic cobalt and electrolytic manganese dioxide (EMD). Preferably, cobalt and EMD are generated in the same electrolytic cell, while nickel is generated in a separate electrolytic cell, while two or more salt separators generate lithium hydroxide with different sulfate contents to allow high-purity lithium hydroxide products and lithium recycling streams for pH control and / or leaching. It is readily understood that the salt separator will also provide an acidic solution, which is then used in the leaching circuit to close the cycle in the process.

[0023] Thus, from a different perspective, the contemplated systems and methods presented herein combine the electroplating of cobalt and manganese dioxide into a single electrolytic cell, recycling the acid and base (lithium hydroxide) during the electroplating of the non-lithium feed metals (cobalt and nickel), thereby avoiding the formation of mixed hydroxides and minimizing costs and feedstock requirements. Most typically, a 2-stage salt separation cell or 3-stage salt separation cell configuration is used. In addition, it should be recognized that the contemplated systems and methods can be easily adapted to black materials containing little or no lithium by using hydroxides of sodium, potassium, ammonium and / or calcium in place of lithium hydroxide.

[0024] For example, refer to Figure 1 , an exemplary overall process 100 can be implemented in which an electrode active material ("black matter") 102 is used as a raw material. In most cases, the black matter is obtained from crushed discarded lithium batteries and generally contains large amounts of cobalt, nickel, copper, lithium, manganese, aluminum and graphite. However, as described above, it should be understood that black matter 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 raw material. It is also preferred that the black matter has been treated to remove plastic components, but further or additional plastic removal is also contemplated. Although not limiting the subject matter of the present invention, it is also preferred that the black matter is dry (or dried) and has a residual water content of no more than 5% by weight, or no more than 4% by weight, or no more than 3% by weight, or no more than 2% by weight, or no more than 1% by weight.

[0025] Also refer to Figure 1 , the dried / dried black mass is fed to a leaching tank 110 where the black mass is pulped using a leachate. Most preferably, the leachate 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 to 6M, and its specific concentration will be at least partially affected by the specific acid used. For example, due to Li 2 SO 4 Due to the solubility limitations of Li (about 3.2 M) and Co (about 2.4 M), the preferred range of sulfuric acid would be 1.5 M to 2.5 M. On the other hand, because MSA is monobasic and lithium methanesulfonate is more 2 SO 4 Significantly more soluble, when using MSA, the preferred range would be 4M to 6M. Typically, sulfuric acid, methanesulfonic acid and disodium EDTA are preferred leachants. In some embodiments, methanesulfonic acid and (possibly) disodium EDTA can be used as leachants.

[0026] It should also be noted that in at least some embodiments, additional reducing agents (e.g., iron (II) sulfate, hydrogen peroxide, etc.) will be used to reduce the Co 3+Reduction to Co 2+ and Mn 4+ Reduction to Mn 2+ into solution. In addition, it is contemplated that the slurry density of the leachate will preferably be between 5 g / L and 300 g / L. Regardless of the specific acid and feedstock used for leaching, it is contemplated that the leachate is concentrated with metal ions and will have a final pH of between 1 and 5. When 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 lead-in material and by using the lead-in material as a pH adjuster to achieve a pH of about 5.

[0027] In some embodiments, elevated temperatures of 60°C to 90°C may be used during the leaching process, 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 performed in batches, which last for 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 than 12 hours. After leaching is complete, the slurry from the leaching tank is typically filtered in a filtration unit 115, and the undissolved residue 117 (mainly graphite or anode material with traces of undissolved metal cations) is removed as a filter cake. If desired, a secondary leaching loop (not shown) may be added to increase recovery and produce a graphite product with a low metal content.

[0028] In at least some embodiments, the resulting pregnant leachate 116 is then fed to a copper recovery tank 120 where copper is preferentially electroplated as metallic copper 122 and iron is preferentially electroplated from Fe 3+ Oxidized to Fe 2+ . Most typically, the copper recovery cell 120 is configured as an electrochemical polishing reactor having a high surface area cathode (e.g., using graphite felt as a flow-through cathode), wherein the electrode potential of the cathode is controlled to preferentially reduce copper. An exemplary configuration of such a polishing reactor suitable for use herein is described in US2022 / 0275527, which is incorporated herein by reference. It will be readily appreciated that the polishing reactor will operate at a sufficiently low current to remove most of the copper present in the leachate without electroplating significant amounts of other electroplatable metals such as cobalt or nickel. Furthermore, while a flow-through cathode having graphite felt is contemplated above, it will be appreciated that various other cathode materials, including stainless steel or titanium, are also considered suitable for use herein.

[0029] After the copper is electrolytically removed, a portion of the thus treated leachate 124 is returned to the leaching tank 110, wherein the Fe 2+ Helps to 3+ Reduction to Co 2+ and Mn 4+ Reduction to Mn 2+In some embodiments, the proportion of the treated leachate returned to the leaching tank is 5% to 98%, while in other embodiments, the proportion returned is 6% to 20%. Another portion of the leachate 124 treated in this way will be sent to the precipitation stage 130, where a LiOH stream 174' is added to raise the system pH to 3 to 5, thereby precipitating impurities such as aluminum and iron in the form of corresponding aluminum and iron hydroxides 132 without precipitating a large amount (e.g., 3% to 5%, or 5% to 10%, or 10% to 15%, or 15% to 20%, or 20% to 30%) of nickel, cobalt, manganese and / or lithium. The aluminum and iron hydroxide precipitate 132 can then be removed by a filtration system and sold or processed. Most preferably, the LiOH solution 174' used to adjust the pH is obtained from a downstream salt separator, as described in more detail below.

[0030] After electrolytic removal of copper (by producing metallic copper) and aluminum and iron (by precipitation), the further treated leachate 134 is then fed to the metal separation stage. In at least some embodiments, the metal separation stage will include one or more than one solvent extraction stage, in which the metal ions are selectively extracted by an organic reagent. For example, the first solvent extraction stage 140 will include a solvent extraction system in which cobalt 142B and manganese 142A are removed from the further treated leachate 134. Among many options, suitable organic solvents include Cyanex 272 and / or equivalent organic solvents. Most typically, the solvent will be diluted in an organic diluent (e.g., kerosene, heptane, ethanol, butane). It is readily understood that a suitable pH during the solvent extraction process will promote the extraction efficiency and selectivity of cobalt and manganese, and in at least some embodiments, the pH is adjusted by adding a LiOH solution or a sulfuric acid solution obtained from a downstream salt separation step, as discussed in further detail below. Of course, it should be understood that the solvent extraction can be performed in one stage or multiple stages to achieve the desired extraction efficiency and selectivity.

[0031] The organic phase thus formed from the first solvent extraction stage loaded with cobalt and manganese is then fed to a stripping stage where a concentrated (e.g. 1M to 6M) acid solution will remove the metal ions. 2 SO 4In some embodiments, the present invention relates to the metal recovery of nickel and EMD. The metal recovery of nickel and EMD is carried out in the electrolytic cell of single electrolytic cell 141 or series connection ...

[0032] After passing through the first solvent exchange stage, the cobalt and manganese depleted leachate can be fed to the second solvent extraction stage 150, where nickel and remaining cobalt are removed by one or more selective organic reagents. Among many suitable choices, contemplated organic reagents for nickel removal include Cyanex 272, Versatic 10 Acid, Lix-84, D2EPHA, and / or other equivalent organic solvents. Again, a suitable pH during the solvent extraction process will promote nickel extraction efficiency and selectivity, and in at least some embodiments, the pH is adjusted by adding LiOH solution or sulfuric acid solution obtained from the downstream salt separation step, as discussed in more detail further below.

[0033] The nickel-laden organic phase thus formed from the second solvent extraction stage is then fed to a stripping stage where a concentrated (e.g. 1M to 6M) acid solution removes the metal ions. 2 SO 4 It can be used in concentrations up to 6 M, while MSA can be used in concentrations up to 5 M. Alternatively, the acid solution can also be other acids, such as hydrochloric acid, nitric acid or other inorganic acids. To recover metallic nickel 152, the acidic stripping solution is fed to a single electrolytic cell 151 or electrolytic cells in series, where the nickel is electroplated as a valuable product.

[0034] After passing through the (preferably dual) solvent exchange system, the nickel-depleted leachate is substantially depleted of metals other than lithium, and the lithium-rich (sulfate or mesylate) leachate thus obtained is then fed to one or more salt separation cells 170 to recover lithium in the form of alkaline LiOH solution 171 / 174 and to generate leaching acid 172 (e.g., H 2 SO 4or MSA), the leaching acid 172 can then be sent to the beginning of the process. The lithium recovery unit 180 receives a portion of the alkaline LiOH solution 171 / 174 and generates a pure lithium product. As needed or desired, an ion exchange system 160 can be used upstream of the salt separation tank 170 to remove any cationic metal impurities, such as cations of Zn, Cu, Fe, Al, Co, Ni, Mn (e.g., using a chelating resin or DOWEX 4195 resin). It is readily understood that the contemplated systems and methods may employ multiple salt separator stages, with two stages or three stages being particularly contemplated.

[0035] For example, in one embodiment, salt separation will occur in two or three stages, wherein the first stage will produce the highest concentration of lithium hydroxide and the lowest concentration of residual sulfate (or methanesulfonate, in which case the leachate is MSA). Most preferably, the LiOH solution produced in the salt separator will be removed from the system and further processed to produce lithium valuable products. For example, water can be evaporated to produce LiOH or LiOH·H 2 Alternatively, the LiOH solution can be treated with gaseous CO 2 It is carbonated to produce lithium carbonate, or it is precipitated as lithium carbonate using soda ash at high temperature. As already noted, the H generated from this first stage 2 SO 4 It will preferably be recycled back into the process, either into the solvent extraction acid stripping system and / or into the leaching system.

[0036] The second stage will have a lower concentration of lithium species. The LiOH solution produced by the second stage will be at a lower concentration and will be sent to the first salt separation tank to increase the concentration. Since the process will require a higher amount of pure LiOH, there are two stages for the production of pure LiOH and only one stage for pure H 2 SO 4 (or MSA) is produced. However, it should be noted that 100% (not counting losses) of the acid will preferably be recycled somewhere in the process, while about 66% of the LiOH will also be recycled to the process. Therefore, the volumes of these recycle streams will need to match the volumes used in the leaching loop and the solvent exchange loop, which will ultimately determine the concentration of LiOH produced in the salt separation tank. In some embodiments of this second stage, a salt separation tank will not be required.

[0037] The third stage will have 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 generated here may contain some contaminants and it will be recycled to the process for pH control. 2 SO 4The effluent from the final salt separation tank (i.e., dilute lithium sulfate) can be (a) fully or partially recycled to the H2O2 solution in the third stage salt separation tank; 2 SO 4 (a) a LiOH production chamber or a MSA production chamber; (b) a LiOH production chamber which is recycled in whole or in part to the third stage salt decomposition tank; (c) both (a) and (b) are carried out simultaneously; or (d) if impurities have accumulated to sufficiently high levels, part of the stream can enter the wastewater treatment system.

[0038] Figure 2 A more detailed process flow diagram of a treatment plant 200 is depicted, wherein a black mass 202 is treated in a leaching stage 210, a selective electrochemical copper removal stage 220, a precipitation stage 230 for the removal of iron and aluminum ions, two solvent exchange stages 240 and 250 for the removal of cobalt, manganese and nickel, an ion exchange stage 260 and three salt separators. Figure 2 It can be readily seen that the apparatus is configured to operate in a closed loop process which receives a ferrous material and produces a variety of metal products in metallic form and lithium in salt form at very high purity.

[0039] exist Figure 2 In an embodiment of the present invention, lithium sulfate (or lithium methanesulfonate) can be provided to the front end of the process from the effluent of the salt separation stage via stream 273. Here, the lithium sulfate stream 273 is fed to the leaching stage 210 together with recycled sulfuric acid (or MSA) 272, which can also include an anode and cathode combination to reduce copper ions to metallic copper. The pregnant leachate 216 can then be filtered in a filtration unit 215 to remove particles, particularly graphite products 217. A portion of the pregnant leachate 216 is returned to the leaching stage 210, while the remaining pregnant leachate is then fed to the precipitation stage 230, where the solution is combined with an alkaline recycled lithium hydroxide solution 274' provided from the second stage (and / or third stage) of the salt separation tank 270. Advantageously, this recycling will not only preserve valuable lithium ions, but also avoid the need for external alkali to raise the pH to precipitate aluminum and iron ions in the form of corresponding hydroxides 232. The precipitate thus formed can then be removed in a pressure filter 231 , thereby producing a further processed leachate 234 .

[0040] The further treated leachate 234 is then fed to the (three-stage) solvent exchange units 240 and 250 for the removal of cobalt and manganese, and the effluent from the solvent exchange unit 240 is fed to the solvent exchange unit 250 for the selective removal of nickel. Figure 2It can be seen that some of the recycled lithium hydroxide stream 274' can also be used in the solvent exchange unit 240, which again preserves lithium in the process and helps to adjust the pH for adsorption of copper and manganese. In addition, it should be understood that the pH of the second stage of the solvent exchange unit 240 can be adjusted using sulfuric acid generated in the process, and most preferably using sulfuric acid from the first salt separator and / or the second salt separator. The cobalt and manganese-rich aqueous phase thus obtained can then be fed to one or more than one Co / EMD electrolytic cells 241 to form metallic cobalt and EMD (electrochemical manganese dioxide). Therefore, it should be recognized that the method proposed herein will advantageously allow the preparation of not only high purity lithium salts, but also EMD and metallic cobalt, both of which are important components in the manufacture of lithium-ion batteries.

[0041] The solvent exchange unit 250 receives the aqueous effluent 244 of the solvent exchange unit 240 and is used to adsorb and remove nickel. Here, nickel is removed by a selective solvent and finally forms metallic nickel 252 by electroplating in the electrolytic cell 251. It should be understood that the aqueous effluent 254 of the solvent exchange unit 250 is now rich in lithium ions and is depleted of copper, iron, aluminum, cobalt, manganese and nickel. Any remaining metal ions (except lithium) can then be removed from the aqueous effluent 254 of the solvent exchange unit 250 in an optional downstream ion exchange unit 260 (here: including three ion exchange beds in series, which can have the same or different selectivities). After the ion exchange unit 260 removes non-lithium impurities, the lithium-rich solution (usually containing lithium sulfate or lithium methanesulfonate) is fed to the salt separation tank 270 (here: three tanks in series), and then sulfuric acid, lithium hydroxide and effluent will be generated.

[0042] exist Figure 2 In the embodiment of the present invention, the first salt separation cell 270A generates a concentrated pure sulfuric acid stream and a concentrated high-purity lithium hydroxide stream 271. It is easy to understand that the concentrated sulfuric acid is suitable for recycling in the method proposed herein, and among many options, the sulfuric acid will be used as an acidulant in the solvent exchange process and / or as an electrolyte for the cobalt / EMD electrolysis cell. The concentrated lithium hydroxide stream of the first salt separation cell 270A can then be used in a lithium recovery unit 280 (which can be configured as a crystallizer) to generate a final lithium salt product 282.

[0043] The effluent from the first salt separation tank 270A is then fed to the second salt separation tank 270B, which again generates a lower purity and lower 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 separation tank can be fed back upstream to the first salt separation tank, such as Figure 2As shown exemplarily. The effluent of the second salt separation tank 270B is fed to the third salt separation tank 270C, which generates another sulfuric acid stream (which is preferably fed back to the second salt separation tank) and a lower purity lithium hydroxide stream 274', which can be recycled back into the process (preferably recycled back 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 separation tank 270C can be fed back to the leaching unit or discarded as a metal-depleted waste stream.

[0044] In some embodiments, the numerals representing the amount, properties such as concentration, reaction conditions, etc. of the components used to describe and claim certain embodiments of the present invention should be understood to be modified by the term "about" in some cases. Therefore, in some embodiments, the numerical parameters listed in the written description and the appended claims are approximate values ​​and can vary according to the desired properties that the specific embodiment attempts to obtain. The statement of the numerical range herein is intended only to be used as a shorthand method for quoting each individual value falling within the range individually. Unless otherwise specified herein, each individual value is incorporated into this specification as if it were quoted individually herein.

[0045] Unless otherwise specified herein or the context is clearly contradictory, all methods described herein can be performed in any suitable order. The use of any and all examples or exemplary language (e.g., "such as" or "as" or "for example") provided for certain embodiments herein is intended only to better illustrate the present invention, rather than to limit the scope of other claims of the present invention. Any language in the specification should not be interpreted as representing any unclaimed element essential to the practice of the present invention.

[0046] As used in this specification and throughout the claims that follow, quantifiers preceding an element include singular and plural references, unless the context clearly indicates otherwise. In addition, as used in this specification, unless the context clearly indicates otherwise, the meaning of "in..." includes "in..." and "on...". In addition, as used in the specification, unless the context clearly indicates otherwise, the term "connected to" is intended to include direct connections (where two interconnected elements are in contact with each other) and indirect connections (where at least one additional element is located between the two elements). Therefore, the terms "connected to" and "connected" are used synonymously.

[0047] It should be obvious to those skilled in the art that, in addition to the modifications already described, there may be more modifications without departing from the inventive concept of this article. Therefore, the subject matter of the present invention is not limited except for the scope of the appended claims. In addition, when interpreting the specification and claims, all terms should be interpreted in the broadest manner consistent with the context. In particular, the terms "comprise" and "comprising" should be interpreted as referring to elements, components or steps in a non-exclusive manner, indicating that the referenced elements, components or steps may exist, or be utilized, or be combined with other elements, components or steps that are not explicitly referenced. When the specification or claim involves at least one of something selected from A, B, C... and N, the text should be interpreted as requiring only one element in the group, rather than A plus N, or B plus N, etc.

Claims

1. A method for recovering metals from waste lithium batteries, comprising: leaching a plurality of different metals in ionic form from the battery material using a leachate to produce a pregnant leachate; removing a first metal from the pregnant leachate by electroplating to produce a treated leachate; removing a second metal from the treated leachate by precipitation to produce a further treated leachate; removing a third metal and optionally a fourth metal from the further treated leachate by solvent exchange to produce a third metal and optionally a fourth metal depleted leachate; The third metal and optionally fourth metal depleted leachate is treated in a salt separator unit to regenerate at least some of the leachate to produce a metal hydroxide solution and an effluent, wherein at least some 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 fourth metal, and optionally wherein at least some of the effluent is used in the leaching step.

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

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

4. A process according to any one of the preceding claims, wherein the leachate is sulphuric acid or methanesulphonic acid, optionally containing a chelating agent.

5. The method of any one of the preceding claims, wherein the first metal is copper, and wherein electroplating comprises preferentially electroplating copper onto the cathode.

6. A method according to any one of the preceding claims, wherein the second metal is aluminium and / or iron.

7. A process according to any one of the preceding claims, wherein the third metal is cobalt and / or manganese.

8. A process according to claim 7, wherein the cobalt and / or manganese are recovered from the organic solvent in a solvent exchange using an acid, and wherein the cobalt and / or manganese are plated as metallic cobalt and EMD in a single electrolytic cell.

9. The process of claim 7, wherein the solvent exchange uses a portion of the regenerated leachate and / or metal hydroxide solution from the salt separator unit.

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

11. A process according to any one of the preceding claims, wherein the optional fourth metal is nickel, and wherein the fourth metal is removed in a separate solvent exchange.

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

13. The process of claim 11, wherein a separate solvent exchange uses a portion of the regenerated leachate and / or metal hydroxide solution from the salt separator unit.

14. The process of claim 12, wherein the acid is recycled in a separate solvent exchange.

15. The method according to any one of the preceding claims, wherein the salt separator unit comprises at least two salt separators.

16. The method of claim 15, wherein a first portion of the metal hydroxide solution from at least one of the two salt separators is further processed to produce LiOH or LiOH.H2O product or a lithium carbonate solution or a lithium carbonate precipitate.

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

18. 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 the fourth metal.

19. The process of any one of the preceding claims, further comprising removing metal ion impurities from the third metal and optional fourth metal depleted leachate using an ion exchange resin or a chelating resin before feeding the third metal and optional fourth metal depleted leachate to the salt separator unit.

20. A method according to any one of the preceding claims, wherein when the battery material is at least partially depleted of lithium ions, the metal hydroxide solution is sodium hydroxide, potassium hydroxide or calcium hydroxide.

21. A method according to any one of the preceding claims, wherein the salt separator unit is a bipolar electrodialysis unit.

Images