Method and system for recovery of metals from spent lithium-ion batteries

Abstract

A method for obtaining metal salts from spent lithium-ion (Li-ion) batteries 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°C to 90°C by applying microwave radiation. The temperature of the first dispersion is maintained 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. The first dispersion 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 at which a first metal salt precipitates.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 400,938, filed August 25, 2022, the entirety of which is incorporated herein by reference for all purposes.

[0002] The present disclosure relates generally to the field of recycling spent lithium ion batteries, and specifically to systems and methods for the recovery of metals from spent lithium ion batteries. [Background technology]

[0003] As automobiles, power tools, and other electrically powered devices become more common, the number of used lithium-based batteries is expected to increase rapidly. Given the finite amounts of metals and other natural resources used as raw materials for lithium-based batteries, economically viable methods for recycling used batteries are needed to keep the cost of the raw materials (and, consequently, the batteries) affordable.

[0004] Lithium-based batteries typically include plastics that form a protective cover for the battery and a portion of the battery's separator. The electrodes are primarily metals, such as copper, iron, and aluminum, depending on the particular battery chemistry being used. The batteries also typically include what is known as black mass, which generally includes graphite and salts of several high-value metals (depending on the particular battery chemistry), in addition to lithium, such as iron, cobalt, manganese, nickel, copper, and aluminum, which form less than about 1% by weight of the scrap battery weight and typically less than about 2% by weight of the battery's active mass. In some of the newer battery chemistries, the black mass may also include trace amounts of other metals, such as rare earths.

[0005] Most current technologies for recycling used lithium batteries utilize pyrometallurgical processes, such as smelting, which require high temperatures, for example, in the range of about 500°C to about 1000°C. As a result, the energy costs associated with the recycling process are high, resulting in metal recovery costs that are substantially higher than the market value of the recovered metals. Furthermore, the amount of each metal recovered is also typically low compared to, for example, hydrometallurgical processes. Therefore, these technologies are not sustainable in the long term.

[0006] While hydrometallurgical processes can provide higher yields and potentially higher purity metal recovery, these processes generally require heating the leach solvate at relatively high temperatures, e.g., in the range of about 80°C to about 150°C, for extended periods of time. Therefore, the energy requirements of such processes remain high. Moreover, handling high-temperature leach solvate poses certain hazards that further increase the cost of such processes.

[0007] As a result, current technologies for recycling used batteries are not cost-effective compared to technologies for obtaining these materials fresh. Therefore, there is a need for cost-effective, low-energy, sustainable, and low-carbon footprint technologies for recovering materials from used batteries. Summary of the Invention

[0008] The embodiments disclosed herein stem from the recognition that high temperatures and / or high-temperature chemical reaction techniques are not required to recover metals from spent lithium-ion batteries. The present application discloses systems and methods for recovering metals from spent lithium-ion batteries, for example, from black mass, using a leaching solvent. Because the leaching solvent used in the disclosed embodiments is an aqueous solution, microwave radiation can be utilized to heat the leaching solvent to a suitable temperature and maintain the temperature at which the metals dissolve from the black mass into the leaching solvent, reducing the time and energy required. Embodiments also utilize leaching solvents that include an oxidizing agent to further increase the efficiency of leaching metals from black mass.

[0009] The leaching solvent of the presently disclosed embodiments is selected to be capable of dissolving all of the various metals used in lithium-ion batteries. Therefore, when black mass from a lithium-ion battery is contacted with the leaching solvent at a suitable temperature, all of the various metals from the battery are dissolved into the leaching solvent. The embodiments disclosed herein further utilize the recognition that when various metals are dissolved in the leaching solvent, salts of the various metals can precipitate at different pH values. Therefore, advantageously, the embodiments disclosed herein enable the separation of the different metals present in lithium-ion batteries without the need to use high-temperature chemical processes, thereby substantially reducing the time, cost, and carbon footprint of recovering metals from lithium-ion batteries.

[0010] Furthermore, as will become apparent, the systems and methods disclosed herein enable the recovery of high purity salts of high value metals, which can be further utilized to obtain high purity high value metals.

[0011] Thus, in at least one embodiment, a method for obtaining metal salts from a portion of a spent lithium ion (Li-ion) battery in contact with a leaching solvent to obtain a first dispersion is provided. 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 in the range 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.

[0012] According to at least one embodiment, a system for recycling used Li-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 break cells of the used Li-ion batteries into fragments. The cleaning chamber is configured to clean the fragments using, for example, water and / or other neutral solvent(s). The one or more storage tanks are configured to store chemicals and may include at least one first storage tank that stores 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 a first reaction chamber of the two or more reaction chambers is coupled to a microwave generator configured to provide microwave generation to reactants in the first reaction chamber, and at least a second reaction chamber 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 corresponding ones of the two or more reaction chambers. The controller is further configured to control the microwave generator to adjust the amount of microwave radiation provided to the first reaction chamber 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. A first filtrate from the reaction products from the first reaction chamber is transferred to a second reaction chamber and contacted with a first base to increase the pH of the first filtrate to a first predetermined value, thereby precipitating a first metal salt.

[0013] Additional features and advantages of the subject technology will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the subject technology. The advantages of the subject technology will be realized and attained by the structures particularly pointed out in the written description and embodiments herein, as well as the accompanying drawings.

[0014] 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.

[0015] Various features of exemplary embodiments of the present disclosure are described below with reference to the drawings. The illustrated embodiments are intended to illustrate, but not limit, the present disclosure. The drawings include the following figures: [Brief explanation of the drawings]

[0016] [Figure 1] 1 illustrates a schematic diagram of an apparatus for recycling spent lithium-ion batteries, according to at least some embodiments of the present disclosure. [Figure 2] 1 shows a flowchart of a method for obtaining metal salts from spent lithium ion batteries, according to at least some embodiments of the present disclosure. [Figure 3A] FIG. 1 is a process flow diagram of a process used in a method for obtaining metal salts from spent lithium ion batteries, according to at least some embodiments of the present disclosure. [Figure 3B] FIG. 1 is a process flow diagram of a process used in a method for obtaining metal salts from spent lithium ion batteries, according to at least some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the subject technology. It should be understood that the subject technology may be practiced without some of these specific details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the subject technology.

[0018] Furthermore, while the description sets forth specific details of various embodiments, it will be understood that the description is illustrative only and should not be construed as limiting. Additionally, while particular embodiments of the present disclosure may be disclosed or illustrated in the context of recycling certain types of lithium-ion batteries, it is contemplated that such embodiments may be used with all types of lithium-ion batteries, using modifications within the scope of the present disclosure and claims. Moreover, 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.

[0019] A typical lithium-ion battery may contain graphite powder and salts of one or more high-value metals, such as lithium, aluminum, copper, cobalt, manganese, nickel, iron, etc., depending on the battery chemistry used. Some commonly used lithium-ion battery types and the content of various metals and other materials in those battery types are provided in Tables 1-6.

[0020] [Table 1]

[0021] [Table 2]

[0022] [Table 3]

[0023] [Table 4]

[0024] [Table 5]

[0025] [Table 6]

[0026] As is evident from Tables 1-6, significant amounts of high-value metals can be recovered from spent Li-ion batteries. The techniques disclosed herein enable economical, sustainable, and large-scale recovery of various high-value metals from spent Li-ion batteries. The methods disclosed herein have low energy requirements, thereby reducing the carbon footprint of the recycling process. Furthermore, instead of obtaining salts from mined metals, the methods disclosed herein advantageously provide high-purity salts of various high-value metals that can be directly used in the manufacture of Li-ion batteries.

[0027] 1 shows a schematic diagram of an apparatus 100 for recycling used lithium-ion batteries, according to at least some embodiments of the present disclosure. In some embodiments, the apparatus 100 includes a crusher 102, a washing chamber 104, one or more chemical storage tanks 106, a controller 108, two or more reaction chambers, such as a separation chamber 110 and a settling chamber 112, one or more wash water tanks 114, one or more recycled water tanks 116, and one or more pumps 120.

[0028] In some embodiments, the crusher 102 is designed to break down cells of used lithium ion batteries (also referred to herein as "used batteries" for convenient reference) into pieces having dimensions ranging from about 1 mm to about 5 cm. In some embodiments, the crusher 102 may include a chamber that can be sealed and evacuated to reduce the amount of oxygen in the chamber, thereby preventing oxidation of the used battery pieces. In some embodiments, the chamber may be repressurized using an inert gas such as, for example, nitrogen or argon.

[0029] In some embodiments, the washing chamber 104 is designed to wash the used battery debris obtained from the crusher 102. Washing the debris may include processes such as, for example, washing the debris with water (e.g., distilled water), sonicating the debris in water or after drying the washed debris, drying the washed and / or sonicated debris, etc.

[0030] In some embodiments, cleaning may be performed at room temperature or at elevated temperatures. In some embodiments, cleaning may be performed in air at atmospheric pressure. Alternatively, or additionally, cleaning may be performed under vacuum and / or an inert atmosphere, for example, in the presence of nitrogen, argon, etc.

[0031] In some embodiments, cleaning the debris may include dispersing the debris from the used battery in a fluid and filtering the debris using one or more filtration processes, such as using one or more meshes, each having a different mesh size. In some embodiments, the mesh size may range from about 50 μm to about 5 mm. For example, the filtration process may include filtering the dispersion through a mesh having a mesh size of about 5 mm, followed by filtering through a mesh having a mesh size of about 1 mm, followed by filtering through a mesh having a mesh size of about 500 μm, followed by filtering through a mesh having a mesh size of about 50 μm. In some embodiments, one or more of these steps may be omitted. Alternatively, or additionally, one or more filtration steps may be added to the process.

[0032] 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, salt solutions, etc.), water, and / or other proprietary solutions containing one or more chemicals useful in the recycling process.

[0033] In some embodiments, each of the one or more storage tanks 106 may be connected to two or more reaction chambers 110, 112. Furthermore, the connections between the storage tanks and the reaction chambers may include control valves that may be controlled by the controller 108. The controller 108 is configured to control the amount of chemical transferred from the storage tanks 106 to the reaction chambers 110, 112 via the control valves (or other mechanisms). For example, the controller 108 may control parameters such as the volume and / or flow rate of the chemical transferred from the storage tanks to the corresponding reaction chambers.

[0034] In some embodiments, the controller 108 may utilize control parameters, such as, for example, pH, temperature, volume, turbidity, density, and / or other parameters associated with the chemicals in a given reaction chamber, to control the volume, mass, and / or flow rate of chemicals transferred from a storage tank to a given reaction chamber. Consequently, the system 100 may measure one or more corresponding control parameters and further include one or more sensors for measuring one or more of the controlled parameters (e.g., volume, mass, flow rate, etc.).

[0035] In some embodiments, the controller 108 may 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 in the reaction chamber. For example, in some embodiments, the controller 108 may control the power input to a microwave generator coupled to the reaction chamber to control the microwave energy delivered to the material in the reaction chamber. The controller 108 may control the power input based on a parameter such as, for example, the temperature of the material in the reaction chamber.

[0036] In some embodiments, two or more reaction chambers may be connected to a rinse water tank 114. The connection between the reaction chambers and the rinse water tank may, in some embodiments, be controlled by a control valve. Similar to the connection between the reaction chambers and the storage tank, the controller 108 may control, via the control valve, the amount and / or flow rate of water transferred from the rinse water tank 114 to the reaction chamber based on parameters such as pH, temperature, volume, turbidity, density, and / or other parameters associated with the chemicals in a given reaction chamber.

[0037] The two or more reaction chambers, in some embodiments, are further connected to a recycled water tank 116. Once the reaction in the reaction chamber is complete, any solid matter that is generated, e.g., precipitated and / or separated within the reaction chamber, is removed. The solid material may be removed, for example, by filtration. In some embodiments, the chemical residue, e.g., the filtrate, is neutralized using a neutralizing solution introduced into the reaction chamber from a corresponding storage tank, e.g., via control of a control valve by the controller.

[0038] In some embodiments, the neutralization process can be carried out in several steps by sequentially increasing the pH of the filtrate by gradually adding a neutralizing solution to sequentially precipitate different materials. 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 solid-state neutralizing chemical, for example, can be added to the reaction chamber to increase the pH of the contents of the reaction chamber.

[0039] In some embodiments, after any possible precipitates resulting from the neutralization reaction have been removed, for example by filtration, the remaining water may be transferred to the recycled water storage tank 116 .

[0040] In some embodiments, the transfer of material to or from one or more of the storage tank 106, the reaction chambers 110, 112, the rinse water tank 114, and / or the recycled water tank 116 may be facilitated by one or more pumps 120. In some embodiments, the one or more pumps 120 are coupled to a controller 108 that can control the one or more pumps 120 to control the flow rate and / or volume of material being transferred.

[0041] In one aspect of the present disclosure, a suitable apparatus, such as, for example, apparatus 100, may be utilized to recycle used batteries. Specifically, in some embodiments, an apparatus, such as apparatus 100, may be utilized to recover various metal salts found in used Li-ion batteries, such as, for example, salts of lithium, aluminum, copper, iron, nickel, cobalt, and manganese.

[0042] FIG. 2 illustrates a flowchart of a method 200 for obtaining metal salts from spent lithium-ion batteries, according to at least some embodiments of the present disclosure. The method 200 may include, at 202, contacting a leaching solvent with a portion of a spent Li-ion battery to obtain a first dispersion. The first dispersion is heated at 204 to a temperature in a range of about 50° C. to about 90° C. by applying microwave radiation to the electrode dispersion. At 206, the temperature of the heated first dispersion is maintained in a range of about 50° C. to about 90° C. for a period in a range of about 10 seconds to about 5 minutes via the controlled application of microwave radiation. At 208, the first dispersion is filtered to obtain a first filtrate. At 210, 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.

[0043] In some embodiments, the portion of the used Li-ion battery is obtained by crushing the lithium ion battery. The process for obtaining a suitable portion of the Li-ion battery may further 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 separating coarse fragments having a size in the range of about 0.5 mm to about 5 mm by utilizing a suitable sieve, followed by further separating finer fragments having a size in the range of about 50 μm to about 0.5 mm by utilizing a second suitable sieve.

[0044] A portion of the spent Li-ion battery, e.g., fine debris and / or black mass, may be introduced into a reaction chamber at 202, where the fine debris and / or black mass (hereinafter collectively referred to as "black mass" for ease of reference) are contacted with a leaching solvent. In some embodiments, the leaching solvent may include an acid, such as, for example, sulfuric acid, hydrochloric acid, oxalic acid, etc. In some embodiments, the leaching solvent may include two or more acids.

[0045] In some embodiments, the leaching solvent may further comprise an oxidizing agent, such as, for example, hydrogen peroxide or nitric acid. In some embodiments, the concentration of the leaching solvent 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 introduction may be controlled via a controller.

[0046] Table 7 provides the concentrations of various materials used in the leaching solvent, according to one example.

[0047] [Table 7]

[0048] Once the leaching solvent is introduced into the reaction chamber, the leaching solvent and black mass are stirred, for example, using a stirrer (which may or may not be controlled by a controller), to form a first dispersion.

[0049] Microwave radiation is then applied to the first dispersion in 204 to heat the first dispersion to a temperature in the range of about 50° C. to about 90° C. Thus, in 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.

[0050] In some embodiments, the application of microwave radiation is controlled by a controller that uses the temperature within the reaction chamber (e.g., the temperature determined using a temperature sensor coupled to the controller) as a feedback parameter. In some embodiments, the controller may be a Proportional-Integral-Derivative (PID) controller, although other types of controllers are contemplated within the scope of the present disclosure.

[0051] Additionally, in some embodiments, the first dispersion in the reaction chamber is stirred while being heated. Stirring the first dispersion can help distribute the heat generated by the application of microwave radiation more evenly throughout the first dispersion. Additionally or alternatively, the first dispersion can be sonicated, for example, by applying ultrasound during the heating process.

[0052] Once the temperature of the first dispersion reaches the desired value, application of microwave radiation is continued to maintain the temperature at the desired value for a period of time ranging from 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.

[0053] In some embodiments, the continuous application of microwave radiation at 204 is controlled using a controller, such as, for example, the same controller used at 204. It should be understood that the continuous application of microwave radiation does not imply constant application of microwave radiation. Thus, in some embodiments, the microwave radiation at 206 may be applied in pulses. Each pulse may have a pulse width ranging from about 0.5 seconds to 5 seconds or more. The microwave pulses may or may not have the same peak power. Thus, in some embodiments, the continuous application of microwave radiation may include applying pulses of microwave radiation and controlling parameters such as, for example, the pulse width, the peak power of the pulses, the pulse rate, and the amount of time the microwave radiation is applied to the first dispersion.

[0054] Additionally, at 206, the first dispersion may be agitated and / or sonicated using ultrasound to more evenly distribute the heat generated from the application of microwave radiation throughout the first dispersion.

[0055] After maintaining the temperature of the first dispersion for a predetermined period of time, the first dispersion is filtered at 208 to obtain a first filtrate. In some embodiments, the first dispersion may be cooled to room temperature before being filtered at 208. In some embodiments, filtering the first dispersion may include passing the first dispersion through one or more filters, meshes, or sieves. In some embodiments, the filters, meshes, or sieves may be designed or selected to allow for separation of solid materials having different sizes. For example, a first mesh, filter, or sieve can separate solid materials having a size greater than about 1 mm, a second mesh, filter, or sieve can separate solid materials having a size in the range of about 0.5 mm to about 1 mm, a third mesh, 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 mesh, filter, or sieve can separate solid materials having a size in the range of about 50 μm to about 100 μm, a fifth mesh, filter, or sieve can separate solid materials having a size in the range of about 10 μm to about 50 μm, a sixth mesh, filter, or sieve can separate solid materials having a size in the range of about 1 μm to about 10 μm, etc.

[0056] It will be appreciated that salts of high-value metals from the black mass are dissolved in the leaching solvent, and the filtration process removes the insoluble 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 high-value metals contained in the battery. In other words, the first filtrate may contain metal ions in their highest oxidation states (due to the presence of an oxidizing agent in the leaching solvent).

[0057] 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 comprises one or more basic salts, such as, for example, sodium carbonate, potassium carbonate, ammonium carbonate, sodium phosphate, sodium hydroxide, potassium hydroxide, ammonium hydroxide, ammonia, etc.

[0058] In some embodiments, the first base may 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 may react with the first base, resulting in the formation of corresponding metal base salts that are generally insoluble in water. As a result, different metal base salts may precipitate from the first filtrate at different pH values ​​as the pH of the first filtrate increases.

[0059] In some embodiments, after the pH of the first filtrate reaches a first predetermined value at which the first metal base salt precipitates, a 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 base salt precipitates.

[0060] In some embodiments, the process can continue by sequentially increasing the pH of the corresponding filtrate to various predetermined values ​​at which different metal base salts precipitate out of the filtrate, until all of the high-value metals have been removed from the filtrate as different metal base salts and the remainder of the filtrate contains a mixture of metal hydroxides as a portion of the metals that remain soluble in water after precipitation of the insoluble metal base salts.

[0061] 3A and 3B illustrate a process flow diagram of an exemplary process for recovering metal salts from spent Li-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.

[0062] [Table 8]

[0063] Figures 3A and 3B illustrate different precipitation units PU01-PU08 in which different metal base salts are precipitated by sequentially increasing the pH of the filtrate. Thus, for example, when the pH of the filtrate is in the range of 2.5-3.2, iron precipitates in the first precipitation unit PU01. Once the insoluble iron salts are removed, the resulting solution is transferred to the second precipitation unit PU02, where more base is added to increase the pH to a range of 3.0-4.0, where insoluble aluminum salts precipitate. The addition of base can continue to increase the pH to a range of 4.2-4.9, where cobalt precipitates, then to a range of 5.0-5.8, where copper precipitates, and so on, until manganese (pH range of 5.0-6.0), nickel (pH range of 6.1-7.6), and lithium (pH range of 8.5-10.5) precipitate from solution.

[0064] Those skilled in the art will understand that although the process flow diagrams in Figures 3A and 3B show that iron precipitates as phosphate and aluminum precipitates as hydroxide, other metal base salts can precipitate at different pH values ​​depending on the base. Thus, for example, all of the metal salts can precipitate as phosphate or carbonate, depending on the particular base used, and will precipitate at different corresponding pH values. Advantageously, the pH range can be controlled, and only certain metal salts can precipitate within a particular pH range, so the resulting precipitate has high purity.

[0065] Those skilled in the art will further appreciate that due to their low solubility in water, metal base salts precipitate out of the filtrate. Nevertheless, these metal base salts are not completely insoluble, and therefore, some of the metals may remain in solution. As a result, even after the addition of a saturating amount of base (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.

[0066] In some embodiments, the final filtrate is neutralized using an acid, such as sulfuric acid, to bring the pH of the solution into the neutral range. The neutralized solution can then be evaporated to yield salts and water that can be recycled into the process.

[0067] 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 method that uses microwave radiation to heat a dispersion of black mass, improving energy efficiency. Furthermore, because the process does not require smelting or other high-temperature processes, no gases are emitted and zero pollution results. Advantageously, the water used in the process can also be recycled, thereby further reducing waste. [Example]

[0068] 100 kg of LCO, LNCA, NMC622, and LFP (25 wt % contribution) batteries were recycled using the methods disclosed herein to recover electrode metals.

[0069] Table 9 provides the amount of electrode metal recovered after the process.

[0070] [Table 9]

[0071] Further considerations In some embodiments, any of the clauses herein may depend on any one of the independent clauses or any one of the dependent clauses. In an aspect, any of the clauses (e.g., dependent or independent clauses) may be combined with any other one or more clauses (e.g., dependent or independent clauses). In an aspect, a claim may include some or all of the words (e.g., steps, actions, means, or components) listed in a clause, sentence, phrase, or paragraph. In an aspect, a claim may include some or all of the words listed in one or more clauses, sentences, phrases, or paragraphs. In an aspect, some of the words in each clause, sentence, phrase, or paragraph may be deleted. In an aspect, additional words or elements may be added within a clause, sentence, phrase, or paragraph. In an aspect, the subject technology may be implemented without utilizing some of the components, elements, functions, or operations described herein. In an aspect, the subject technology may be implemented using additional components, elements, functions, or operations.

[0072] The subject technology is exemplified, for example, according to various aspects described below. Various examples of aspects of the subject technology are described as numbered clauses (1, 2, 3, etc.) for convenience. These are provided as examples and are not intended to limit the subject technology. Note that any of the dependent clauses may be combined in any combination and placed in their own independent clauses, e.g., clause 1 or clause 5. Other clauses may be presented in a similar manner.

[0073] Clause 1. A method for obtaining metal salts from spent lithium ion (Li-ion) batteries, the method comprising: contacting a leaching solvent with a portion of the spent Li-ion battery to obtain a first dispersion; heating the first dispersion to a temperature in a range of 50°C to 90°C by applying microwave radiation; maintaining the temperature of the first dispersion in a range of 50°C to 90°C for a period in a 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.

[0074] Clause 2. The method of clause 1, wherein the first metal salt comprises lithium, aluminum, iron, cobalt, copper, manganese, and / or nickel.

[0075] Clause 3. The method of clause 1, wherein the leaching solvent comprises sulfuric acid.

[0076] Clause 4. The method of clause 3, wherein the leaching solvent further comprises an oxidizing agent.

[0077] Clause 5. The method of clause 4, wherein the oxidizing agent is hydrogen peroxide.

[0078] Clause 6. The method of clause 1, wherein the leaching solvent has a pH in the range of 0 to 7.0.

[0079] Clause 7. The method of clause 1, wherein heating the first dispersion further comprises agitating the first dispersion while applying microwave radiation.

[0080] Clause 8. The method of clause 1, wherein maintaining the temperature of the first dispersion includes controlling the application of microwave radiation using a controller.

[0081] Clause 9. The method of clause 1, wherein heating the first dispersion comprises heating the first dispersion to a temperature in the range of 60°C to 80°C.

[0082] Clause 10. The method of clause 1, wherein maintaining the temperature comprises maintaining the temperature of the first dispersion within a range of 60°C to 80°C for a period within a range of 30 seconds to 5 minutes.

[0083] Clause 11. The method of clause 1, wherein the portion of the used lithium ion battery comprises metal debris and black mass comprising graphite and metal oxides.

[0084] Clause 12. The method of clause 11, wherein filtering the first dispersion comprises filtering the first dispersion through a sieve.

[0085] Clause 13. The method of clause 1, wherein heating the first dispersion further comprises continuously stirring the first dispersion while applying microwave radiation.

[0086] Clause 14. The method of clause 1, wherein maintaining the temperature of the first dispersion further comprises continuously stirring the first dispersion while applying microwave radiation.

[0087] Clause 15. The process of clause 1, wherein the first base comprises sodium carbonate and / or ammonium carbonate.

[0088] Clause 16. The method of clause 1, further comprising obtaining a second filtrate after precipitation of the first metal salt.

[0089] 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.

[0090] Clause 18. A system for recycling used lithium ion batteries, the system comprising: a crusher configured to break cells of the used lithium ion batteries into fragments; a washing chamber configured to wash the fragments; one or more storage tanks configured to store chemicals, including at least a first storage tank for storing a first base; two or more reaction chambers coupled to the one or more storage tanks via one or more pumps and valves, wherein at least a first reaction chamber of the two or more reaction chambers is 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 is coupled to the first storage tank; and a controller. The controller is configured to control one or more pumps and / or one or more valves to adjust the transfer rate and amount of chemicals transferred from one or more storage tanks to corresponding ones of the two or more reaction chambers, and a microwave generator to adjust the amount of microwave radiation provided to the first reaction chamber 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. The washed debris is placed in the first reaction chamber for contact with a leaching solvent. A first filtrate from the reaction product from the first reaction chamber is transferred to a second reaction chamber and contacted with a first base to increase the pH of the first filtrate to a first predetermined value and precipitate a first metal salt.

[0091] Clause 19. The system of clause 18, wherein at least one of the one or more reaction chambers includes an agitator configured to agitate the reactants therein.

[0092] Clause 20. The system of clause 18, wherein the grinder comprises a chamber configured to be maintained under vacuum and / or have an inert atmosphere.

[0093] Clause 21. The system of clause 18, wherein the leaching solvent comprises sulfuric acid and an oxidizing agent.

[0094] Clause 22. The system of clause 18, wherein the predetermined temperature range is 50°C to 90°C.

[0095] Clause 23. The system of clause 18, wherein the predetermined period is in the range of 10 seconds to 5 minutes.

[0096] Clause 24. The system of clause 18, wherein the leaching solvent has a pH in the range of 0 to 7.0.

[0097] Clause 25. The system of clause 18, wherein maintaining the temperature includes maintaining the temperature of the electrode dispersion within a range of 60°C to 80°C for a period within a range of 30 seconds to 5 minutes.

[0098] Clause 26. The system of clause 18, wherein the first base comprises sodium carbonate and / or ammonium carbonate.

[0099] The foregoing description is provided to enable one skilled in the art to practice the various configurations described herein. While the subject technology has been particularly described with reference to various figures and configurations, it should be understood that these are for illustrative purposes only and should not be construed as limiting the scope of the subject technology.

[0100] There may be many other ways to implement the subject technology. The various functions and elements described herein may be divided differently than shown without departing from the scope of the subject technology. Various modifications to these configurations will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other configurations. Thus, many changes and modifications may be made to the subject technology by those skilled in the art without departing from the scope of the subject technology.

[0101] It is understood that the specific order or hierarchy of steps in the processes disclosed is an illustration of example approaches. Based on design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged. Some steps may be performed simultaneously. The accompanying method claims present elements of the various steps in a sample order, and are not intended to be limited to the specific order or hierarchy presented.

[0102] As used herein, the term "about" preceding a quantity indicates a discrepancy with the quantity. The discrepancy may be caused by manufacturing tolerances or may be based on differences in measurement techniques. In some cases, the discrepancy may be up to 10% from the listed value. One of ordinary skill in the art will understand that the discrepancy with a particular quantity may be context-dependent, and thus, for example, a discrepancy with dimensions at the microscale or nanoscale may be different from a discrepancy at the meter scale.

[0103] As used herein, the phrase "at least one of" preceding a list of items modifies the list as a whole, rather than each member (i.e., each item) of the list, using the word "and" or "or" to separate any of the items. The phrase "at least one of" does not require the selection of at least one of each listed item; rather, the phrase allows for a meaning including at least one of any one of the items, and / or at least one of any combination of the items, and / or at least one of each of the items. By way of example, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" refers to A only, B only, or C only, any combination of A, B, and C, and / or at least one of each of A, B, and C, respectively.

[0104] Terms such as "top," "bottom," "front," and "rear" as used in this disclosure should be understood to refer to any frame of reference, rather than the typical gravitational frame of reference. Thus, the top, bottom, front, and rear surfaces may extend upward, downward, diagonally, or horizontally within the gravitational frame of reference.

[0105] Furthermore, to the extent that the terms "include," "have," or the like are used in the description or claims, such terms are intended to be inclusive in the same manner as "comprise" would be interpreted as "comprise" when used as a transitional term in a claim.

[0106] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations.

[0107] Reference to an element in the singular is intended to mean "one and only one," but "one or more," unless specifically stated otherwise. Masculine pronouns (e.g., his) include feminine and neuter pronouns (e.g., her and its), and vice versa. The term "some" refers to one or more. Underlined and / or italicized headings and subheadings are used for convenience only and do not limit the subject technology, and are not to be recited in connection with the interpretation of the subject technology description. All structural and functional equivalents to the elements of the various configurations described throughout this disclosure that are known or later become known to those skilled in the art are expressly incorporated herein by reference and are intended to be included in the subject technology. Furthermore, nothing disclosed herein is intended as a public dedication, regardless of whether such disclosure is expressly recited in the description above.

Claims

1. 1. A method for obtaining metal salts from spent lithium ion (Li-ion) batteries, the method comprising: contacting a leaching solvent with a portion of a spent Li-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 within a range of 50°C to 90°C for a period of time within a 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; 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.

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

3. The method of claim 1 , wherein the leaching solvent comprises sulfuric acid.

4. The method of claim 3 , wherein the leaching solvent further comprises an oxidizing agent.

5. The method of claim 4 wherein the oxidizing agent is hydrogen peroxide.

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

0.

7. The method of claim 1 , wherein heating the first dispersion further comprises agitating the first dispersion while applying the microwave radiation.

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

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

10. 10. The method of claim 1, wherein maintaining the temperature comprises maintaining the temperature of the first dispersion within a range of 60°C to 80°C for a period within a range of 30 seconds to 5 minutes.

11. 10. The method of claim 1, wherein the portion of the spent lithium ion battery comprises metal debris and black mass comprising graphite and metal oxides.

12. The method of claim 11 , wherein filtering the first dispersion comprises filtering the first dispersion through a sieve.

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

14. 10. The method of claim 1, wherein maintaining the temperature of the first dispersion further comprises continuously stirring the first dispersion while applying the microwave radiation.

15. 10. The method of claim 1, wherein the first base comprises sodium carbonate and / or ammonium carbonate.

16. 10. The method of claim 1, further comprising obtaining a second filtrate after said precipitation of said first metal salt.

17. 17. The method of claim 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.

18. 1. A system for recycling used lithium ion batteries, the system comprising: a crusher configured to break cells of the used lithium ion battery into fragments; a washing chamber configured to wash the debris; one or more storage tanks configured to store chemicals, including at least one first storage tank that stores a first base; two or more reaction chambers coupled to the one or more storage tanks via one or more pumps and valves, wherein at least a first reaction chamber of the two or more reaction chambers is 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 is coupled to the first storage tank; the one or more pumps and / or the one or more valves for regulating the transfer rate and amount of chemicals transferred from the one or more storage tanks to corresponding ones of the two or more reaction chambers; and a controller configured to control the microwave generator to adjust the amount of microwave radiation provided to the first reaction chamber to heat the reactants in the first reaction chamber to a temperature within a predetermined range and to maintain the temperature of the reactants within the predetermined range for a predetermined period of time; the washed pieces are placed in the first reaction chamber for contact with a leaching solvent; a first filtrate from the reaction product from the first reaction chamber is transferred to the second reaction chamber and contacted with the first base to increase the pH of the first filtrate to a first predetermined value and precipitate a first metal salt.

19. 20. 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. 20. The system of claim 18, wherein the grinder comprises a chamber maintained under vacuum and / or configured to have an inert atmosphere.

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

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

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

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

0.

25. 20. The system of claim 18, wherein maintaining the temperature comprises maintaining the temperature of the electrode dispersion within a range of 60°C to 80°C for a period within a range of 30 seconds to 5 minutes.

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

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