Methods and systems for recovering metals from spent lithium ion batteries

Abstract

A method for obtaining a metal salt from a spent lithium ion (Li-ion) battery may include contacting a leaching solvent with a portion of the spent lithium ion battery to form a first dispersion. The first dispersion is heated to a temperature in the range of 50 DEG C to 90 DEG C by applying microwave radiation. The temperature of the first dispersion is maintained in the range of 50 DEG C to 90 DEG C for a period of 10 seconds to 5 minutes by further applying microwave radiation to the heated first dispersion. The first dispersion liquid is filtered to obtain a first filtrate. A first base is contacted with the first filtrate to increase the pH of the first filtrate to a first predetermined value to precipitate a first metal salt.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to U.S. Provisional Patent Application No. 63 / 400,938, filed on August 25, 2022, which is incorporated herein by reference in its entirety for all purposes. Technical Field

[0003] The present disclosure relates generally to the field of recycling of spent lithium-ion batteries, and in particular to systems and methods for recovering metals from spent lithium-ion batteries. Background Art

[0004] With the increasing popularity of electric devices such as cars and power tools, the amount of waste lithium-based batteries is expected to grow rapidly. Given that the amount of metals and other natural resources used as raw materials for lithium-based batteries is limited, it is necessary to adopt economically viable methods to recycle waste batteries to maintain an affordable cost for the raw materials (and batteries).

[0005] Lithium-based batteries typically include plastic that forms part of the battery's protective cover and separator. The electrodes are primarily metals such as copper, iron, and aluminum, depending on the specific battery chemistry used. These batteries also include a substance commonly referred to as black matter, which, in addition to lithium, typically includes graphite and salts of several precious metals (depending on the specific battery chemistry), such as iron, cobalt, manganese, nickel, copper, and aluminum, which forms less than about 1% of the weight of spent batteries and typically less than about 2% of the weight of the battery's active mass. The black matter of some newer battery chemistries may also contain trace amounts of other metals, such as rare earths.

[0006] Most existing technologies for recycling spent lithium batteries utilize high-temperature metallurgical processes (such as smelting), which require high temperatures, for example, in the range of approximately 500°C to approximately 1000°C. Consequently, the energy costs associated with the recycling process are high, and the cost of recovered metals is significantly higher than the market value of the recovered metals. Furthermore, the amount of each metal recovered is typically lower compared to, for example, hydrometallurgical processes. Therefore, these technologies are unsustainable in the long term.

[0007] While hydrometallurgical processes can provide higher yields and potentially higher purity of recovered metals, these processes typically require heating the leaching solvent at relatively high temperatures, for example, in the range of about 80°C to about 150°C, for extended periods of time. Consequently, the energy requirements of such processes remain high. Furthermore, handling of the high-temperature leaching solvent poses certain hazards, which further increases the cost of such processes.

[0008] Therefore, current technologies for recycling spent batteries are not cost-effective relative to technologies for recovering these materials. Therefore, there is a need for cost-effective, low-energy, sustainable and low-carbon footprint technologies to recover materials from spent batteries. Summary of the Invention

[0009] The embodiments disclosed herein are based on the recognition that high temperatures and / or high-temperature chemical techniques are not required to recover metals from spent lithium-ion batteries. This application discloses systems and methods for recovering metals from spent lithium-ion batteries, such as from ferrous materials, using a leaching solvent. Because the leaching solvent used in the presently disclosed embodiments is an aqueous solution, microwave radiation can be used to reduce the time and energy required to heat the leaching solvent to the appropriate temperature and maintain the temperature at which metals from the ferrous material dissolve in the leaching solvent. The embodiments also utilize a leaching solvent containing an oxidant to further improve the efficiency of leaching metals from the ferrous material.

[0010] The leaching solvent of the presently disclosed embodiments is selected so that it can dissolve all of the various metals used in lithium-ion batteries. Thus, once the black material from the lithium-ion battery comes into contact with the leaching solvent at the appropriate temperature, all of the various metals from the battery will dissolve into the leaching solvent. The embodiments disclosed herein further exploit the recognition that once the various metals are dissolved in the leaching solvent, salts of the various metals can be precipitated at different pH values. Thus, advantageously, the embodiments disclosed herein are able to separate the different metals present in lithium-ion batteries without having to use high-temperature chemical processes, thereby significantly reducing the time, cost, and carbon footprint of recovering metals from lithium-ion batteries.

[0011] Furthermore, it is apparent that the systems and methods disclosed herein are capable of recovering high purity precious metal salts, which can be further used to obtain high purity precious metals.

[0012] Therefore, in at least one embodiment, a method for obtaining a metal salt from a spent lithium-ion (Li-ion) battery comprises contacting a leaching solvent with a portion of the spent lithium-ion battery to obtain a first dispersion. The first dispersion is heated to a temperature in the range of 50°C to 90°C by applying microwave radiation. The temperature of the electrode dispersion is maintained in the range of 50°C to 90°C for a period of 10 seconds to 5 minutes by further applying microwave radiation to the heated electrode dispersion. The first dispersion is then filtered to obtain a first filtrate. A first base is contacted with the first filtrate to increase the pH of the first filtrate to a first predetermined value, at which a first metal salt precipitates from the first filtrate.

[0013] According to at least one embodiment, a system for recycling spent lithium-ion batteries may include a crusher, a cleaning chamber, one or more storage tanks, two or more reaction chambers, and a controller. The crusher is configured to crush the battery cells of the spent lithium-ion battery into fragments. The cleaning chamber is configured to clean the fragments, for example, using water and / or other neutral solvents. The one or more storage tanks are configured to store chemicals and may include at least one first storage tank for storing a first base. The two or more reaction chambers are coupled to the one or more storage tanks via one or more pumps and valves. At least the first of the two or more reaction chambers is coupled to a microwave generator configured to provide microwave generation to the reactants in the first reaction chamber, and at least the second of the two or more reaction chambers is coupled to the first storage tank. The controller is configured to control the one or more pumps and / or one or more valves to adjust the transfer rate and amount of chemicals transferred from the one or more storage tanks to the corresponding reaction chambers in the two or more reaction chambers. The controller is also configured to control the microwave generator to adjust the amount of microwave radiation provided to the first reaction chamber, thereby heating the reactants in the first reaction chamber to a temperature within a predetermined range and maintaining the temperature of the reactants within the predetermined range for a predetermined period of time. A first filtrate of the reaction product from the first reaction chamber is transferred to a second reaction chamber to contact with a first base to increase the pH of the first filtrate to a first predetermined value, thereby precipitating a first metal salt.

[0014] Additional features and advantages of the subject technology will be set forth in the following description, and in part will become apparent from the description, or may be learned through practice of the subject technology. The advantages of the subject technology will be realized and obtained through the structures particularly pointed out in the written description and its embodiments as well as the accompanying drawings.

[0015] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the subject technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The various features of the illustrative embodiments of the present disclosure are described below with reference to the accompanying drawings. The illustrative embodiments are intended to illustrate the present invention, but not to limit the present invention. The drawings include the following figures:

[0017] Figure 1 An apparatus for recycling spent lithium-ion batteries according to at least some embodiments of the present disclosure is schematically shown.

[0018] Figure 2 A flow chart of a method for obtaining metal salts from spent lithium-ion batteries according to at least some embodiments of the present disclosure is shown.

[0019] Figure 3is a process flow diagram of a process used in a method of obtaining metal salts from spent lithium-ion batteries according to at least some embodiments of the present disclosure. DETAILED DESCRIPTION

[0020] In the detailed description that follows, numerous specific details are set forth to provide a comprehensive understanding of the subject technology. It should be understood that the subject technology can be practiced without some of these specific details. In other cases, well-known structures and techniques are not shown in detail to avoid obscuring the subject technology.

[0021] Furthermore, while this description sets forth specific details of various embodiments, it should be understood that the description is illustrative only and should not be construed as limiting in any way. Furthermore, it is contemplated that while specific embodiments of the present disclosure may be disclosed or shown in the context of recycling certain types of lithium-ion batteries, such embodiments may be used with all types of lithium-ion batteries using modifications within the scope of the present disclosure and claims. Furthermore, various applications of such embodiments and modifications thereof that may occur to those skilled in the art are also encompassed by the general concepts described herein.

[0022] Depending on the battery chemistry used, a typical lithium-ion battery may contain graphite powder and salts of one or more precious metals, such as lithium, aluminum, copper, cobalt, manganese, nickel, iron, etc. Tables 1 to 6 provide some common lithium-ion battery types and the content of various metals and other materials in these battery types.

[0023] Table 1: Lithium cobalt oxide (LCO) batteries

[0024]

[0025] Table 2: Lithium Nickel Cobalt Aluminum (LNCA) Batteries

[0026]

[0027] Table 3: Ratio of 1 / 3 nickel, manganese and cobalt in active cathode (NMC111) batteries

[0028]

[0029] Table 4: Nickel, manganese, and cobalt ratios of 60% / 20% / 20% in active cathode (NMC622) batteries

[0030]

[0031] Table 5: Nickel, manganese and cobalt ratios of 80% / 10% / 10% in active cathode (NMC811) batteries

[0032]

[0033] Table 6: Lithium iron phosphate (LFP) batteries

[0034]

[0035] As can be seen from Tables 1 to 6, a large amount of precious metals can be recovered from spent lithium-ion batteries. The technology disclosed herein enables the economical, sustainable, and large-scale recovery of various precious metals from spent lithium-ion batteries. The disclosed method has low energy requirements, thereby reducing the carbon footprint of the recovery process. In addition, the disclosed method provides high-purity salts of various precious metals, which can be advantageously used directly in the manufacture of lithium-ion batteries, rather than obtaining the salts from mined metals.

[0036] Figure 1 A schematic diagram of an apparatus 100 for recycling spent lithium-ion batteries according to at least some embodiments of the present disclosure is shown. In some embodiments, the apparatus 100 includes a crusher 102, a cleaning chamber 104, one or more chemical storage tanks 106, a controller 108, two or more reaction chambers such as a separation chamber 110, a settling chamber 112, one or more clean water tanks 114, one or more recovery water tanks 116, and one or more pumps 120.

[0037] In some embodiments, the crusher 102 is designed to crush the battery cells of spent lithium-ion batteries (also referred to herein as "spent batteries" for ease of reference) into fragments ranging in size from about 1 mm to about 5 cm. In some embodiments, the crusher 102 can include a sealable and evacuable chamber to reduce the amount of oxygen in the chamber, thereby preventing oxidation of the spent battery fragments. In some embodiments, the chamber can be repressurized using an inert gas (e.g., nitrogen or argon).

[0038] In some embodiments, the cleaning chamber 104 is designed to clean the spent battery fragments obtained from the shredder 102. Cleaning the fragments may include processes such as washing the fragments with water (e.g., distilled water), ultrasonicating the fragments while in water or after drying the washed fragments, drying the washed and / or ultrasonicated fragments, and the like.

[0039] In some embodiments, cleaning can be performed at room temperature or elevated temperature. In some embodiments, cleaning can be performed in air at atmospheric pressure. Alternatively or additionally, cleaning can be performed under vacuum and / or in an inert atmosphere, such as in the presence of nitrogen, argon, etc.

[0040] In some embodiments, cleaning debris can include dispersing the debris of the waste battery in a fluid and using one or more filtration processes (e.g., using one or more screens, each screen having a different screen size) to filter the debris. In some embodiments, the screen size can be in the range of about 50 microns to about 5 millimeters. For example, the filtration process can include filtering the dispersion in sequence through a screen with a screen size of about 5 millimeters, subsequently filtering through a screen with a screen size of about 1 millimeter, subsequently filtering through a screen with a screen size of about 500 microns, subsequently filtering through a screen with a screen size of about 50 microns. In some embodiments, one or more of these steps can be omitted. Alternatively or additionally, one or more filtration steps can be added in the process.

[0041] In some embodiments, one or more storage tanks 106 may store chemicals such as leaching chemicals, acids, neutralizing solutions (e.g., alkaline solutions, acid solutions, saline solutions, etc.), water, and / or other specialized solutions including one or more chemicals that may be used in the recovery process.

[0042] In some embodiments, each of one or more storage tanks 106 can be connected to two or more reaction chambers 110, 112. In addition, the connections between the storage tanks and the reaction chambers can include control valves that can be controlled by a controller 108. The controller 108 is configured to control the amount of chemicals transferred from the storage tanks 106 to the reaction chambers 110, 112 via the control valves (or other mechanisms). For example, the controller 108 can control parameters such as the volume and / or flow rate of the chemicals transferred from the storage tanks to the corresponding reaction chambers.

[0043] In some embodiments, controller 108 can utilize control parameters such as pH, temperature, volume, turbidity, density, and / or other parameters associated with the chemical in a given reaction chamber to control the volume, mass, and / or flow rate of the chemical transferred from the storage tank to the given reaction chamber. Accordingly, system 100 can also include one or more sensors for measuring one or more corresponding control parameters and for measuring one or more controlled parameters (e.g., volume, mass, flow rate, etc.).

[0044] In some embodiments, the controller 108 can control the temperature of the material in the reaction chamber, for example, by controlling the amount of heat delivered to the reaction chamber or the material within the reaction chamber. For example, in some embodiments, the controller 108 can control the power input to a microwave generator coupled to the reaction chamber to control the amount of microwave energy delivered to the material in the reaction chamber. The controller 108 can control the power input based on a parameter such as the temperature of the material in the reaction chamber.

[0045] In some embodiments, two or more reaction chambers can be connected to a clean water tank 114. In some embodiments, the connection between the reaction chamber and the clean water tank can be controlled by a control valve. Similar to the connection between the reaction chamber and the storage tank, the controller 108 can control the amount and / or flow rate of water transferred from the clean water tank 114 to the reaction chamber via the control valve based on parameters such as pH, temperature, volume, turbidity, density, and / or other parameters related to the chemical substances in a given reaction chamber.

[0046] In some embodiments, two or more reaction chambers are further connected to a recovery water tank 116. When the reaction in the reaction chamber is completed, any solid material generated in the reaction chamber, such as precipitation and / or separation, is removed. The solid material can be removed, for example, by filtration. In some embodiments, the remaining portion of the chemical substance, such as the filtrate, is neutralized using, for example, a neutralizing solution, which is introduced into the reaction chamber from the corresponding storage tank by the controller controlling the control valve.

[0047] In some embodiments, the neutralization process can be carried out in several steps, by gradually adding a neutralizing solution to sequentially increase the pH of the filtrate so as to sequentially precipitate different substances. For example, a first precipitate (e.g., a first metal salt) can be obtained at a first pH, a second precipitate can be obtained at a second pH, and so on. In such embodiments, the amount and flow rate of the neutralizing solution added to the reaction chamber can be controlled by a control valve based on the pH of the contents in the reaction chamber. In some embodiments, instead of a neutralizing solution, a neutralizing chemical (e.g., a solid state) can be added to the reaction chamber to increase the pH of the contents of the reaction chamber.

[0048] In some embodiments, after removing any possible precipitate generated by the neutralization reaction, such as by filtration, the remaining water may be transferred to a recovered water storage tank 116 .

[0049] In some embodiments, transfer of material to or from one or more of the storage tank 106, reaction chambers 110, 112, clean water tank 114, and / or recovery water tank 116 can be facilitated by one or more pumps 120. In some embodiments, the one or more pumps 120 are coupled to a controller 108, which can control the one or more pumps 120 to control the flow rate and / or volume of the material being transferred.

[0050] In aspects of the present disclosure, a suitable apparatus (e.g., apparatus 100) can be utilized to recycle spent batteries. Specifically, in some embodiments, an apparatus such as apparatus 100 can be used to recycle salts of various metals found in spent lithium-ion batteries, such as salts of lithium, aluminum, copper, iron, nickel, cobalt, and manganese.

[0051] Figure 2 A flow chart of a method 200 for obtaining metal salts from spent lithium-ion batteries according to at least some embodiments of the present disclosure is shown. Method 200 may include, at 202, contacting a leaching solvent with a portion of the spent lithium-ion battery to obtain a first dispersion. At 204, heating the first dispersion to a temperature in the range of about 50°C to about 90°C by applying microwave radiation to the electrode dispersion. At 206, maintaining the temperature of the heated first dispersion in the range of about 50°C to about 90°C for a period of about 10 seconds to about 5 minutes by controlled application of microwave radiation. At 208, filtering the first dispersion to obtain a first filtrate. At 210, contacting a first base with the first filtrate to increase the pH of the first filtrate to a first predetermined value, at which a first metal salt is precipitated from the first filtrate.

[0052] In some embodiments, a portion of the spent lithium-ion batteries is obtained by crushing the lithium-ion batteries. The process for obtaining a suitable portion of the lithium-ion batteries may also include steps such as separating the crushed portion through a series of sieves to separate materials of different sizes. For example, in some embodiments, the separation may include using a suitable sieve to separate coarse fragments having a size range of about 0.5 mm to about 5 mm, and then further using a second suitable sieve to separate fine fragments having a size range of about 50 microns to about 0.5 mm.

[0053] A portion of the spent lithium-ion battery, such as fine fragments and / or black matter, can be introduced into a reaction chamber, where the fine fragments and / or black matter (hereinafter collectively referred to as "black matter" for ease of reference) are contacted with a leaching solvent at 202. In some embodiments, the leaching solvent can include an acid, such as sulfuric acid, hydrochloric acid, oxalic acid, etc. In some embodiments, the leaching solvent can include more than one acid.

[0054] In some embodiments, the leaching solvent may also include an oxidizing agent, such as hydrogen peroxide or nitric acid. In some embodiments, the concentration of the leaching solvent acid may be in the range of about 0.5N to about 10N. In some embodiments, the leaching solvent may have a pH of about 0. In some embodiments, the pH of the leaching solvent may be in the range of about 0 to about 7.0. In some embodiments, the leaching solvent is introduced into the reaction chamber from a storage tank. The amount and / or flow rate of the leaching solvent introduced may be controlled by a controller.

[0055] Table 7 provides the concentrations of various materials used in the leaching solvent according to one example.

[0056] Table 7: Specifications of leaching solvents according to examples.

[0057]

[0058] After the leaching solvent is introduced into the reaction chamber, the leaching solvent and the black material are stirred, for example, using an agitator (which may or may not be controlled by a controller), to form a first dispersion.

[0059] Next, at 204, microwave radiation is applied to the first dispersion to heat the first dispersion to a temperature in the range of about 50° C. to about 90° C. Thus, at 206, the first dispersion can be heated to a temperature of, for example, about 50° C., about 55° C., about 60° C., about 65° C., about 70° C., about 75° C., about 80° C., about 85° C., about 90° C., or any temperature between any two of these values.

[0060] In some embodiments, the application of microwave radiation is controlled by a controller that uses the temperature in the reaction chamber (e.g., determined using a temperature sensor coupled to the controller) as a feedback parameter. In some embodiments, the controller can be a proportional-integral-derivative (PID) controller, although other types of controllers are contemplated within the scope of the present disclosure.

[0061] Furthermore, in some embodiments, the first dispersion in the reaction chamber is stirred while being heated. Stirring the first dispersion can help to more evenly distribute the heat generated by the application of microwave radiation throughout the first dispersion. Additionally or alternatively, the first dispersion can be sonicated during the heating process, for example by applying ultrasound.

[0062] Once the temperature of the first dispersion reaches the desired value, microwave radiation is continued to maintain the temperature at the desired value for a period of time in the range of about 10 seconds to about 5 minutes at 208. For example, the temperature of the first dispersion can be maintained at the desired value for about 10 seconds, about 15 seconds, about 20 seconds, about 25 seconds, about 30 seconds, about 35 seconds, about 40 seconds, about 45 seconds, about 50 seconds, about 55 seconds, about 60 seconds, about 70 seconds, about 80 seconds, about 90 seconds, about 100 seconds, about 120 seconds, about 140 seconds, about 160 seconds, about 180 seconds, about 200 seconds, about 220 seconds, about 240 seconds, about 260 seconds, about 280 seconds, about 300 seconds, or any amount of time between any two of these values.

[0063] In some embodiments, the continuous application of microwave radiation at 204 is controlled using a controller (e.g., the same controller used in 204). It should be understood that continuously applying microwave radiation does not necessarily mean continuously applying microwave radiation. Thus, in some embodiments, at 206, microwave radiation can be applied in pulses. Each pulse can have a pulse width ranging from about 0.5 seconds to 5 seconds or longer. The microwave pulses may or may not have the same peak power. Thus, in some embodiments, the continuous application of microwave radiation can include the application of pulses of microwave radiation and controlling parameters such as pulse width, peak power of the pulses, pulse rate, and the total amount of time the microwave radiation is applied to the first dispersion.

[0064] Additionally, at 206 , the first dispersion may be stirred and / or sonicated using ultrasound to more evenly distribute heat generated by the application of microwave radiation through the first dispersion.

[0065] After maintaining the temperature of the first dispersion for a predetermined period of time, at 208, the first dispersion is filtered to obtain a first filtrate. In some embodiments, the first dispersion can be cooled to room temperature before filtering at 208. In some embodiments, filtering the first dispersion can include passing the first dispersion through one or more filters, screens, or sieves. In some embodiments, the filters, screens, or sieves can be designed or selected to separate solid materials of different sizes. For example, a first screen, filter, or sieve can separate solid materials having a size greater than about 1 mm; a second screen, filter, or sieve can separate solid materials having a size in the range of about 0.5 mm to about 1 mm; a third screen, filter, or sieve can separate solid materials having a size in the range of about 0.1 mm to about 0.5 mm; a fourth screen, filter, or sieve can separate solid materials having a size in the range of about 50 microns to about 100 microns; a fifth screen, filter, or sieve can separate solid materials having a size in the range of about 10 microns to about 50 microns; a sixth screen, filter, or sieve can separate solid materials having a size in the range of about 1 micron to about 10 microns; and so on.

[0066] It will be appreciated that the salts of the precious metals from the black mass dissolve in the leaching solvent, and the filtration process removes the undissolved portion of the black mass, which primarily comprises graphite. Thus, at the end of 208, the first filtrate primarily comprises dissolved metal salts of the precious metals included in the cell. In other words, the first filtrate may include metal ions in their highest oxidation state (due to the presence of the oxidant in the leaching solvent).

[0067] The first filtrate can then be transferred to another reaction chamber, such as a precipitation chamber, where a first base is contacted with the first filtrate at 210. The first base can be a solution or a solid. In some embodiments, the first base includes one or more basic salts, such as sodium carbonate, potassium carbonate, ammonium carbonate, sodium phosphate, sodium hydroxide, potassium hydroxide, ammonium hydroxide, ammonia, and the like.

[0068] In some embodiments, the first base can be gradually introduced into the precipitation chamber to gradually increase the pH of the first filtrate. As the pH of the first filtrate increases, different metal ions can react with the first base to form corresponding metal alkali salts, which are generally insoluble in water. Thus, as the pH of the first filtrate increases, different metal alkali salts can be precipitated from the first filtrate at different pH values.

[0069] In some embodiments, after the pH of the first filtrate reaches a first predetermined value at which the first metal alkali salt precipitates, the remaining portion of the first filtrate is filtered to obtain a second filtrate. In some embodiments, the second filtrate is transferred to another precipitation chamber. In some embodiments, a second base (which may be the same as or different from the first base) is contacted with the second filtrate to further increase the pH of the second filtrate until the pH of the second filtrate reaches a second predetermined value at which the second metal alkali salt precipitates.

[0070] In some embodiments, the process may continuously and sequentially increase the pH of the corresponding filtrate to different predetermined values ​​at which different metal alkali salts are precipitated from the filtrate until all of the precious metals are removed from the filtrate as different metal alkali salts, and the remainder of the filtrate comprises a mixture of metal hydroxides of the metal portion that remains soluble in water after precipitation of the insoluble metal alkali salts.

[0071] Figure 3 A process flow diagram is shown of an exemplary process for obtaining metal salts from spent lithium-ion batteries according to at least some embodiments of the present disclosure. Table 8 provides a list of abbreviations used in the process flow diagram and their corresponding meanings.

[0072] Table 8: Abbreviations used in process flow diagrams

[0073]

[0074] Figure 3Different precipitation units PU01-PU08 are shown, wherein different metal alkali salts are precipitated by sequentially increasing the pH of the filtrate therein. Thus, for example, iron is precipitated in the first precipitation unit PU01 when the pH of the filtrate is in the range of 2.5-3.2. Once the insoluble iron salts are removed, the resulting solution is transferred to the second precipitation unit PU02, where more alkali is added to raise the pH to the range of 3.0-4.0, at which point insoluble aluminum salts precipitate. Alkali addition can be further continued, raising the pH to the range of 4.2-4.9, at which point cobalt precipitates, then to the range of 5.0-5.8, at which point copper precipitates, and so on, until manganese (pH range 5.0-6.0), nickel (pH range 6.1-7.6), and lithium (pH range 8.5-10.5) are precipitated from the solution.

[0075] Those skilled in the art will understand that although Figure 3 The process flow diagram shows that iron precipitates as phosphate and aluminum precipitates as hydroxide, but other metal salts can precipitate at different pH values ​​depending on the base. Thus, for example, all metal salts can precipitate as phosphates or carbonates, depending on the specific base used, and at different corresponding pH values. Advantageously, because the pH range is controllable and only specific metal salts precipitate within a specific pH range, the resulting precipitate is of high purity.

[0076] It will be further understood by those skilled in the art that alkali metal salts precipitate from the filtrate due to their low solubility in water. However, these alkali metal salts are not completely insoluble, and therefore, some metal may remain in solution. Thus, even after adding a saturating amount of alkali (e.g., when the pH of the filtrate is in the range of 13.5-14.0), the remaining solution is primarily a mixture of various metal hydroxides.

[0077] In some embodiments, an acid (e.g., sulfuric acid) is used to neutralize the final filtrate to bring the pH of the solution into the neutral range. The neutralized solution can then be evaporated to obtain the salt and water, which can be recycled back into the process.

[0078] Therefore, the present disclosure provides a system and method for obtaining metal salts from spent lithium-ion batteries. The method disclosed herein is a low-temperature process that uses microwave radiation to heat a dispersion of a black substance, improving energy efficiency. Furthermore, since the process does not require smelting or other high-temperature processes, there are no gas emissions, achieving zero pollution. Advantageously, the water used in the process can also be recycled, further reducing waste.

[0079] Example

[0080] 100 kg of LCO, LNCA, NMC622 and LFP (contributing 25 wt %) batteries were recycled using the process disclosed herein to recover electrode metals.

[0081] Table 9 provides the amount of electrode metal recovered after the process.

[0082] Table 9: Amount of metal (salt) recovered after precipitation

[0083] Compound Quantity (kg) <![CDATA[FePO4]]> 13.53 <![CDATA[Al(OH)3]]> 3.34 <![CDATA[CoCO3]]> 23.22 <![CDATA[CuCO3]]> 3.95 <![CDATA[MnCO3]]> 3.35 <![CDATA[NiCO3]]> 24.31 <![CDATA[Li2CO3]]> 38.7

[0084] Further considerations

[0085] In some embodiments, any clause herein may be attached to any independent clause or any dependent clause. In one aspect, any clause (e.g., dependent or independent clause) may be combined with any other one or more clauses (e.g., dependent or independent clause). In one aspect, a claim may include some or all of the words (e.g., steps, operations, devices, or parts) listed in a clause, sentence, phrase, or paragraph. In one aspect, a claim may include some or all of the words listed in one or more clauses, sentences, phrases, or paragraphs. In one aspect, some words in each clause, sentence, phrase, or paragraph may be deleted. In one aspect, additional words or components may be added to a clause, sentence, phrase, or paragraph. In one aspect, subject technology may be implemented without utilizing some of the parts, components, functions, or operations described herein. In one aspect, subject technology may be implemented utilizing additional parts, components, functions, or operations.

[0086] For example, the subject technology is described in terms of the various aspects described below. For convenience, various examples of various aspects of the subject technology are described as numbered clauses (1, 2, 3, etc.). These are provided as examples and do not limit the subject technology. It should be noted that any of the dependent clauses can be combined in any combination and placed in the corresponding independent clause, such as Clause 1 or Clause 5. Other clauses can be presented in a similar manner.

[0087] Item 1. A method for obtaining a metal salt from a spent lithium-ion (Li-ion) battery, the method comprising: contacting a leaching solvent with a portion of the spent lithium-ion battery to obtain a first dispersion; heating the first dispersion to a temperature in the range of 50°C to 90°C by applying microwave radiation; maintaining the temperature of the first dispersion in the range of 50°C to 90°C for a period in the range of 10 seconds to 5 minutes by further applying microwave radiation to the heated first dispersion; filtering the first dispersion to obtain a first filtrate; and contacting a first base with the first filtrate to increase the pH of the first filtrate to a first predetermined value, at which a first metal salt precipitates from the first filtrate.

[0088] Clause 2. The method of Clause 1, wherein the first metal salt comprises lithium, aluminum, iron, cobalt, copper, manganese, and / or nickel.

[0089] Clause 3. The method of Clause 1, wherein the leaching solvent comprises sulfuric acid.

[0090] Clause 4. The method of Clause 3, wherein the leaching solvent further comprises an oxidizing agent.

[0091] Clause 5. The method of Clause 4, wherein the oxidizing agent is hydrogen peroxide.

[0092] Clause 6. The method of Clause 1, wherein the pH of the leaching solvent is in the range of 0 to 7.0.

[0093] Clause 7. The method of Clause 1, wherein heating the first dispersion further comprises stirring the first dispersion while applying the microwave radiation.

[0094] Clause 8. The method of Clause 1, wherein maintaining the temperature of the first dispersion comprises controlling the application of the microwave radiation using a controller.

[0095] Clause 9. The method of Clause 1, wherein heating the first dispersion comprises heating the first dispersion to a temperature in a range of 60°C to 80°C.

[0096] Clause 10. The method of Clause 1, wherein maintaining the temperature comprises maintaining the temperature of the first dispersion in a range of 60°C to 80°C for a period of time in a range of 30 seconds to 5 minutes.

[0097] Clause 11. The method of Clause 1, wherein the portion of the spent lithium-ion battery comprises metal flakes and a black substance comprising graphite and metal oxides.

[0098] Clause 12. The method of Clause 11, wherein filtering the first dispersion comprises filtering the first dispersion through a sieve.

[0099] Clause 13. The method of Clause 1, wherein heating the first dispersion further comprises continuously stirring the first dispersion while applying the microwave radiation.

[0100] Clause 14. The method of Clause 1, wherein maintaining the temperature of the first dispersion further comprises continuously stirring the first dispersion while applying the microwave radiation.

[0101] Clause 15. The process of Clause 1, wherein the first base comprises sodium carbonate and / or ammonium carbonate.

[0102] Clause 16. The method of Clause 1, further comprising obtaining a second filtrate after precipitation of the first metal salt.

[0103] Clause 17. The method of Clause 16, further comprising contacting a second base with the second filtrate to increase the pH of the second filtrate to a second predetermined value to precipitate a second metal salt.

[0104] Clause 18. A system for recycling spent lithium-ion batteries, the system comprising: a crusher configured to break down battery cells of the spent lithium-ion batteries into fragments; a cleaning chamber configured to clean the fragments; one or more storage tanks configured to store chemicals, including at least one first storage tank storing a first base; two or more reaction chambers coupled to the one or more storage tanks via one or more pumps and valves, at least a first reaction chamber of the two or more reaction chambers coupled to a microwave generator configured to provide microwave radiation to reactants in the first reaction chamber, and at least a second reaction chamber of the two or more reaction chambers coupled to the first storage tank; and a controller. The controller is configured to control: the one or more pumps and / or the one or more valves to adjust the transfer rate and amount of chemicals from the one or more storage tanks to corresponding reaction chambers of the two or more reaction chambers, and the microwave generator to adjust the amount of microwave radiation provided to the first reaction chamber, thereby heating the reactants in the first reaction chamber to a temperature within a predetermined range and maintaining the temperature of the reactants within the predetermined range for a predetermined period of time. The cleaned debris is placed in the first reaction chamber to contact with a leaching solvent. A first filtrate of the reaction product from the first reaction chamber is transferred to the second reaction chamber to contact with the first base to increase the pH of the first filtrate to a first predetermined value to precipitate a first metal salt.

[0105] Clause 19. The system of Clause 18, wherein at least one of the one or more reaction chambers comprises an agitator configured to agitate the reactants therein.

[0106] Clause 20. The system of Clause 18, wherein the crusher comprises a chamber configured to be maintained under vacuum and / or with an inert atmosphere.

[0107] Clause 21. The system of Clause 18, wherein the leaching solvent comprises sulfuric acid and an oxidizing agent.

[0108] Clause 22. The system of Clause 18, wherein the predetermined temperature range is 50°C to 90°C.

[0109] Clause 23. The system of clause 18, wherein the predetermined period of time is in the range of 10 seconds to 5 minutes.

[0110] Clause 24. The system of Clause 18, wherein the leaching solvent has a pH in the range of 0 to 7.0.

[0111] Clause 25. The system of Clause 18, wherein maintaining the temperature comprises maintaining the temperature of the electrode dispersion in a range of 60°C to 80°C for a period of time in a range of 30 seconds to 5 minutes.

[0112] Clause 26. The system of Clause 18, wherein the first base comprises sodium carbonate and / or ammonium carbonate.

[0113] The foregoing description is provided to enable those skilled in the art to practice the various configurations described herein. Although the subject technology has been described in detail with reference to various figures and configurations, it should be understood that these are for illustrative purposes only and should not be taken as limiting the scope of the subject technology.

[0114] There may be many other ways to implement the subject technology. The various functions and components described herein may be divided differently from those shown without departing from the scope of the subject technology. Various modifications to these configurations will be apparent to those skilled in the art, and the general principles defined herein may be applied to other configurations. Therefore, those of ordinary skill in the art may make many changes and modifications to the subject technology without departing from the scope of the subject technology.

[0115] It should be understood that the specific order or hierarchy of steps in the disclosed processes is illustrative of exemplary methods. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the processes can be rearranged. Some steps can be performed simultaneously. The accompanying method claims present components of the various steps in an exemplary order and are not meant to be limited to the specific order or hierarchy presented.

[0116] As used herein, the term "about" preceding a quantity indicates variation from the stated quantity. This variation may be due to manufacturing tolerances or differences in measurement techniques. In some cases, the variation from the stated value may be as much as 10%. One of ordinary skill in the art will understand that variations in a particular quantity may be context-dependent, and thus, for example, variations in dimensions on the micrometer or nanometer scale may differ from variations on the meter scale.

[0117] As used herein, the phrase "at least one" preceding a list of items, and the use of the terms "and" or "or" to separate any items, modifies the entire list, not each member of the list (i.e., each item). The phrase "at least one" does not require selection of at least one of every item listed; rather, the phrase allows for a meaning that includes at least one of any item, and / or at least one of any combination of items, and / or at least one of each item. For example, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" each refers to only A, only B, or only C; any combination of A, B, and C; and / or at least one of each of A, B, and C.

[0118] As used herein, terms such as "top," "bottom," "front," and "back" should be understood to refer to an arbitrary reference frame, not just the ordinary gravitational reference frame. Thus, the top, bottom, front, and back surfaces may extend upward, downward, diagonally, or horizontally in a gravitational reference frame.

[0119] Furthermore, with respect to use of the terms "including," "having," and the like in the specification or claims, such terms are intended to be inclusive in a manner similar to how the term "comprising" is interpreted when used as a transitional term in a claim.

[0120] The word “exemplary” is used herein to mean “serving as an example, example, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations.

[0121] Unless otherwise specified, reference to a singular component is not intended to mean "one and only one," but rather "one or more." Masculine pronouns (e.g., his) include the feminine and neuter genders (e.g., she and it), and vice versa. The term "some" refers to one or more. Headings and subheadings in underscores and / or italics are used for convenience only and do not limit the subject technology and are not to be referenced in conjunction with interpretation of the description of the subject technology. All structural and functional equivalents to the components of the various configurations described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the subject technology. In addition, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly recited in the above description.

Claims

1. A method for obtaining metal salts from waste lithium-ion (Li-ion) batteries, the method comprising: contacting a leaching solvent with a portion of the spent lithium ion battery to obtain a first dispersion; heating the first dispersion to a temperature in the range of 50°C to 90°C by applying microwave radiation; maintaining the temperature of the first dispersion in the range of 50°C to 90°C for a period in the range of 10 seconds to 5 minutes by further applying microwave radiation to the heated first dispersion; filtering the first dispersion to obtain a first filtrate; and A first base is contacted with the first filtrate to increase the pH of the first filtrate to a first predetermined value at which a first metal salt is precipitated from the first filtrate.

2. The method according to claim 1, wherein: The first metal salt comprises lithium, aluminum, iron, cobalt, copper, manganese and / or nickel.

3. The method according to claim 1, wherein: The leaching solvent comprises sulfuric acid.

4. The method according to claim 3, wherein: The leaching solvent also includes an oxidizing agent.

5. The method according to claim 4, wherein: The oxidizing agent is hydrogen peroxide.

6. The method according to claim 1, wherein: The leaching solvent has a pH in the range of 0 to 7.

0.

7. The method according to claim 1, wherein: Heating the first dispersion further comprises stirring the first dispersion while applying the microwave radiation.

8. The method according to claim 1, wherein: Maintaining the temperature of the first dispersion includes controlling the application of the microwave radiation using a controller.

9. The method according to claim 1, wherein: Heating the first dispersion includes heating the first dispersion to a temperature in a range of 60°C to 80°C.

10. The method according to claim 1, wherein: Maintaining the temperature includes maintaining the temperature of the first dispersion in a range of 60°C to 80°C for a period of time in a range of 30 seconds to 5 minutes.

11. The method according to claim 1, wherein: The portion of the spent lithium-ion battery includes metal flakes and a black substance including graphite and metal oxides.

12. The method according to claim 11, wherein: Filtering the first dispersion includes filtering the first dispersion through a sieve.

13. The method according to claim 1, wherein: Heating the first dispersion further comprises continuously stirring the first dispersion while applying the microwave radiation.

14. The method according to claim 1, wherein: Maintaining the temperature of the first dispersion further comprises continuously stirring the first dispersion while applying the microwave radiation.

15. The method according to claim 1, wherein: The first base comprises sodium carbonate and / or ammonium carbonate.

16. The method according to claim 1, wherein: The method further comprises obtaining a second filtrate after precipitation of the first metal salt.

17. The method of claim 16, wherein the method further comprises contacting a second base with the second filtrate to increase the pH of the second filtrate to a second predetermined value to precipitate a second metal salt.

18. A system for recycling waste lithium-ion batteries, the system comprising: a crusher configured to break down the battery cells of the waste lithium-ion batteries into fragments; a cleaning chamber configured to clean the debris; one or more storage tanks configured to store chemicals, the one or more storage tanks including at least one first storage tank storing a first base; two or more reaction chambers, the two or more reaction chambers being coupled to the one or more storage tanks via one or more pumps and valves, at least a first reaction chamber of the two or more reaction chambers being coupled to a microwave generator configured to provide microwave radiation to reactants in the first reaction chamber, and at least a second reaction chamber of the two or more reaction chambers being coupled to the first storage tank; as well as A controller configured to control: the one or more pumps and / or the one or more valves to regulate the transfer rate and amount of the chemical species transferred from the one or more storage tanks to corresponding reaction chambers of the two or more reaction chambers, and the microwave generator to adjust the amount of microwave radiation provided to the first reaction chamber so as to heat the reactants in the first reaction chamber to a temperature within a predetermined range and maintain the temperature of the reactants within the predetermined range for a predetermined period of time, wherein the cleaned fragments are placed in the first reaction chamber to contact with the leaching solvent, and The first filtrate of the reaction product from the first reaction chamber is transferred to the second reaction chamber to contact with the first base, thereby increasing the pH of the first filtrate to a first predetermined value to precipitate a first metal salt.

19. The system of claim 18, wherein: At least one of the one or more reaction chambers includes an agitator configured to agitate the reactants therein.

20. The system of claim 18, wherein: The crusher includes a chamber configured to be maintained under vacuum and / or with an inert atmosphere.

21. The system of claim 18, wherein: The leaching solvent comprises sulfuric acid and an oxidizing agent.

22. The system of claim 18, wherein: The predetermined temperature range is 50°C to 90°C.

23. The system of claim 18, wherein: The predetermined period of time is in the range of 10 seconds to 5 minutes.

24. The system of claim 18, wherein: The leaching solvent has a pH in the range of 0 to 7.

0.

25. The system of claim 18, wherein: Maintaining the temperature includes maintaining the temperature of the electrode dispersion in a range of 60° C. to 80° C. for a period of time in a range of 30 seconds to 5 minutes.

26. The system of claim 18, wherein: The first base comprises sodium carbonate and / or ammonium carbonate.

Images