Electrolyte obtained through charged crushing and recycling of waste lithium battery and resource utilization method of electrolyte

Abstract

The invention discloses a waste lithium battery charged crushed and recycled electrolyte and a resource utilization method thereof, the system directly crushes the charged waste lithium battery under a protective atmosphere, and a carbonic ester organic solvent in the electrolyte is recycled through low-temperature condensation; then, constructing an H < + > / Mn < + > (Mn < + > = Ni < 2 + >, Co < 2 + > and Mn < 2 + >) dual-catalysis system, and carrying out in-situ hydrolysis on the carbonic ester under a high-temperature condition to convert the carbonic ester into lower alcohol with reduction activity; the obtained alcohol solution serves as a green reducing agent to be used for acid leaching of the ternary black powder, high-valence metal is efficiently reduced, the high leaching rate is achieved, and consumption of exogenous chemicals is reduced. According to the method, a pre-discharging step is omitted, electrolyte pollution is avoided, traditional reducing agents such as sulfur dioxide are replaced, safe, low-carbon and high-valued waste lithium battery all-component collaborative recovery is achieved, environment friendliness and economic feasibility are achieved, and an innovative technical path is provided for large-scale green recovery of waste lithium batteries.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of recycling and resource utilization of waste lithium batteries, and particularly relates to a waste lithium battery charged crushing and recycling of electrolyte and a resource utilization method thereof. BACKGROUND

[0002] Lithium-ion batteries have become the main power source for electric vehicles due to their high energy density, long cycle life, and environmental friendliness. With the rapid growth of the number of electric vehicles, a large number of lithium batteries have entered the retired stage, and efficient, safe, and environmentally friendly recycling has become an urgent issue in the industry. Currently, the lithium battery recycling process mainly faces the following three technical challenges:

[0003] First, the safety discharge problem in the crushing link. Crushing is the first key step in the recycling process. The traditional method requires discharging the waste battery first to reduce the safety risk caused by the rapid release of residual electricity during the crushing process. Existing discharge technologies mainly include dry and wet methods: the dry method dissipates electrical energy through external resistance loading, but has problems such as long discharge time, large equipment, poor adaptability to different types of batteries, and easy rebound of electrical energy; the wet method short-circuits the battery by immersing it in a salt solution (such as sodium sulfate, sodium chloride), which is fast and complete, but can cause corrosion of the battery pole piece, and water can penetrate into the battery and react with lithium hexafluorophosphate to generate hydrofluoric acid, which corrodes subsequent equipment and causes electrolyte leakage, resulting in organic pollutants and fluorine and phosphorus pollution. Therefore, developing an efficient and safe charged crushing technology to achieve safety crushing in a discharged or charged state is an important direction to break through the recycling bottleneck.

[0004] Second, the problem of resource recycling of electrolyte. The main component of electrolyte in waste lithium batteries is carbonic acid ester organic solvent (such as EC, DMC, EMC, etc.), which is traditionally treated as hazardous waste, resulting in high cost and resource waste. The electrolyte contains organic solvents and lithium salts, which can easily cause environmental pollution if discarded or improperly treated. Efficient separation and resource recycling of electrolyte is a key link to improve the economic and environmental benefits of recycling.

[0005] Finally, the optimization demand of wet leaching technology for positive electrode material. Nickel-cobalt-manganese (NCM) ternary positive electrode material is the focus of recycling due to its high value metals. The current wet process mainly uses acid leaching combined with reducing agents (such as sulfur dioxide, ascorbic acid, etc.) to reduce high-valence metals to soluble divalent ions for extraction. However, the commonly used reducing agents have obvious defects: sulfur dioxide requires a high-pressure gas delivery system and the tail gas is corrosive and environmentally risky, making the operation complex and requiring high safety requirements; and organic reducing agents such as ascorbic acid are costly and difficult to be applied on a large scale. Therefore, developing a low-cost, efficient, and environmentally friendly new reducing system or leaching process is of great significance to reduce the cost of recycling and improve the metal leaching rate.

[0006] In summary, to promote the large-scale and clean development of the lithium battery recycling industry, it is urgent to make breakthroughs in three key technologies: safe crushing technology for charged batteries, resource utilization of electrolytes, and low-cost and high-efficiency leaching processes, so as to achieve safe, economical and green recycling throughout the entire process. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the present invention discloses a method for recycling electrolyte from waste lithium batteries by crushing them while they are charged and the method for resource utilization thereof, which can solve or at least alleviate one or more of the above-mentioned problems or other problems existing in the prior art.

[0008] This invention provides a method for recovering electrolyte from waste lithium batteries by crushing them while they are still charged, and for its resource utilization, comprising the following steps:

[0009] S1. Close the valve plate between the buffer box and the crusher in the crushing system and the discharge valve. Open the feed valve to put in the waste lithium batteries to be processed. After feeding, immediately close the feed valve to form a closed chamber.

[0010] S2. Introduce protective gas into the material buffer bin through the air inlet of the crushing system and start the crusher.

[0011] S3. Open the valve plate between the buffer box and the crusher to allow the waste lithium batteries to be processed to enter the crusher. After being broken down into flaky materials by the crusher, the waste lithium batteries enter the material buffer bin.

[0012] S4. When waste lithium batteries are crushed, the organic solvent in the electrolyte evaporates due to shearing and temperature rise, and mixes with the protective gas to form a mixed gas. This mixed gas enters the heat exchange system through the gas outlet. After cooling, the organic solvent condenses into liquid and is separated and collected through the condenser. The protective gas is then recycled at low temperature.

[0013] S5, By constructing H + / M n+ The dual-catalytic system converts carbonate compounds in liquid organic solvents into reducing alcohols in situ, and then uses the reducing alcohol solution to enhance the efficient leaching of nickel, cobalt, and manganese from black powder.

[0014] Preferably, in step S5, the efficient leaching step is as follows:

[0015] S501. The separated and recovered liquid organic solvent is added to deionized water at a mass ratio of 1:(5~10) to prepare a homogeneous organic-water mixed solution; then, a solution containing M is introduced. n+ Aqueous solutions of transition metal ions regulate M n+ Adjust the total concentration to 0.02–0.1 mol / L; then add 6–13% dilute sulfuric acid to adjust the H₂ concentration in the system. +The concentration was maintained in the range of 0.25–1.0 mol / L to construct H + / M n+ The synergistic dual-catalytic reaction system had a reaction time of 2 hours.

[0016] S502, The nickel-cobalt-manganese ternary battery black powder slurry is fed to the leaching reactor at a liquid-to-solid ratio of (2.5~10):1; then, H-processed black powder slurry is added. + / M n+ The amount of the reducing lower alcohol solution obtained by the dual-catalytic system is 1 / 30 of the total slurry by mass; then, dilute sulfuric acid with a concentration of 6-13% is added to adjust the pH of the system to 1-2; the temperature is raised to 60-90°C and the reduction reaction is carried out at a constant temperature for 2 hours to obtain a leachate with stable ionic valence state.

[0017] Preferably, step S5 further includes the reuse of the leachate, as follows:

[0018] S503. Take a portion of the leachate from step S502 and reuse it in step S501 for use in the formation of H with sulfuric acid. + / M n+ Dual catalytic system, regulating M n+ Total concentration up to 0.02–0.1 mol / L.

[0019] Preferably, in step S1, the crushing system consists of a battery inlet, an inlet valve, a buffer tank, a valve plate, a crusher, a material buffer bin, and an outlet valve, arranged from top to bottom. Closing both the inlet valve and the outlet valve simultaneously creates a closed chamber between them.

[0020] The material buffer bin is provided with an air inlet on its side wall and an air outlet on its buffer box.

[0021] When protective gas is introduced into the crushing system, the protective gas enters the material buffer chamber from the inlet, and discharges the air between the inlet valve and the outlet valve from the outlet of the buffer chamber, so that the space between the inlet valve and the outlet valve is in a protective atmosphere of protective gas.

[0022] Preferably, in step S2, the protective gas is selected from one or more of nitrogen, argon and carbon dioxide.

[0023] Preferably, in step S4, the heat exchange system includes a compressor, a heat exchanger, and a condenser connected in sequence by pipelines; the air inlet of the compressor is connected to the protective gas outlet of the crushing system via a pipeline, and the air outlet of the condenser is connected back to the protective gas inlet of the crushing system via a pipeline, forming a closed-loop circulation circuit.

[0024] Preferably, in step S4, the heat exchange system further includes an oxygen sensor, an activated carbon adsorber, and a fresh protective gas storage tank; an external discharge branch is provided on the pipeline between the compressor and the outlet of the crushing system, the outlet of which is connected to the activated carbon adsorber, and an external discharge valve is installed on the external discharge branch; a circulation valve is provided on the main gas pipeline near the compressor to control gas reflux.

[0025] The outlet of the fresh protective gas storage tank is equipped with a replenishment valve. Its outlet end is connected to the gas supply pipeline between the condenser and the air inlet of the crushing system through a pipeline. This is used to replenish high-purity protective gas when the pressure in the closed chamber is insufficient or the oxygen content exceeds the standard, so as to ensure that the entire crushing process is always in a safe, inert, oxygen-free environment.

[0026] Preferably, after step S5, a further deep treatment of residual trace organic matter in the leachate is included, as follows:

[0027] S6. Add ozone to the leachate in the leaching reactor to decompose the residual organic solvent and reduce the concentration of residual organic matter to less than 500 mg / L.

[0028] Preferably, in step S4, the temperature inside the sealed chamber is controlled below 50°C.

[0029] Preferably, in step S3, the pressure inside the sealed chamber is 0.09~0.1MPa.

[0030] The present invention has the following beneficial effects:

[0031] By directly crushing charged waste lithium batteries under a protective atmosphere, and recovering carbonate organic solvents from the electrolyte through low-temperature condensation; subsequently, an H... + / M n+ (M) n+ =Ni 2+ Co 2+ Mn 2+ This invention employs a dual-catalytic system to hydrolyze carbonates in situ at high temperatures, converting them into reducing lower alcohols. The resulting alcohol solution serves as a green reducing agent for the acidic leaching of ternary lithium-ion batteries, efficiently reducing high-valence metals and achieving a high leaching rate. Simultaneously, a portion of the leaching solution containing metal ions is recycled back into the catalytic system, forming an internal cycle and reducing the consumption of external chemicals. This invention eliminates the pre-discharge step, avoids electrolyte pollution, and replaces traditional reducing agents such as hydrogen peroxide, achieving safe, low-carbon, and high-value synergistic recycling of all components from spent lithium-ion batteries. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of this disclosure, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0033] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0034] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments designed in the embodiments and comparative examples of this invention are commonly used reagents and instruments, all of which are commercially available. Unless otherwise specified, the experimental methods used in the embodiments and comparative examples are conventional methods.

[0035] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0036] Example 1

[0037] The crushing system consists of, from top to bottom, a battery inlet, an inlet valve, a buffer tank, a valve plate, a crusher, a material buffer bin, and an outlet valve. Simultaneously closing both the inlet and outlet valves creates a closed chamber between them. The material buffer bin has an air inlet on its side wall and an air outlet. Protective gas enters the material buffer bin through the air inlet, expelling the air between the inlet and outlet valves through the outlet, thus creating a protective atmosphere between them. This structure isolates the battery crushing system from external air, preventing oxygen contamination and ensuring a low-oxygen environment. Other components of the crushing system and their connections are existing technology and will not be described further.

[0038] like Figure 1 As shown, the present invention provides a method for recycling electrolyte from waste lithium batteries by crushing them while they are still charged, and for the resource utilization of the electrolyte, comprising the following steps:

[0039] S1. Close the valve plate between the buffer tank and the crusher in the crushing system, as well as the discharge valve. Open the feed valve to add the waste lithium batteries to be processed. Immediately after feeding, close the feed valve to form a closed chamber. Specific operations are as follows:

[0040] Close the valve plate between the buffer tank and the crusher in the crushing system, and simultaneously close the discharge valve of the crushing system; then, open the feed valve at the top of the crushing system and put the waste lithium batteries to be processed into the buffer tank; after feeding is completed, immediately close the feed valve so that the space between the feed valve and the discharge valve forms a closed chamber.

[0041] S2. Introduce a protective gas (such as one or more of nitrogen, argon, and carbon dioxide) into the material buffer bin through the air inlet of the crushing system, and start the crusher; the pressure in the closed chamber is 0.09~0.1MPa;

[0042] S3. Open the valve plate between the buffer tank and the crusher to allow the waste lithium batteries to enter the crusher. The waste lithium batteries are broken down into flakes by the crusher and then enter the material buffer bin. This step completes the battery crushing process while the batteries are still charged. During the crushing process, residual charge release and temperature rise of the waste lithium batteries are involved. After the waste lithium batteries are crushed, the organic solvents in the electrolyte may come into contact with the outside environment, potentially causing deflagration and explosion. The protective gas in the crushing system has a dual function: firstly, to maintain an oxygen-free environment in the sealed chamber or to control the oxygen concentration below 1% (volume fraction) to effectively inhibit the ignition and combustion of organic matter; secondly, to control the gas flow and flow rate (usually set at 12~15m³). 3 / h) removes the heat generated during the crushing process, thereby stabilizing the temperature of the closed chamber within the set safe operating range, i.e., the temperature does not exceed 50℃;

[0043] S4. When used lithium batteries are crushed, the organic solvent in the electrolyte evaporates due to shearing and temperature rise, mixing with the protective gas to form a mixed gas. This mixed gas enters the heat exchange system through the outlet, and after cooling, the organic solvent condenses into a liquid and is separated and collected through a condenser. The protective gas is then recycled at low temperature. The specific operation is as follows:

[0044] During the crushing process of waste lithium batteries, the organic solvents in the electrolyte (mainly carbonate compounds such as ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC)) volatilize due to mechanical shearing and local temperature rise, mixing with the protective gas introduced into the system to form a mixed gas containing organic solvent vapors. This mixed gas is discharged through the outlet of the crushing system and enters the heat exchange system. In the heat exchange system, the mixed gas is cooled, causing the organic solvent vapors to condense into liquid, thus achieving gas-liquid separation. The separated liquid organic solvents are collected in a condenser, while the protective gas is refluxed or recycled at a low temperature.

[0045] S5, By constructing H + / M n+ The dual-catalytic system converts carbonate compounds into reducing alcohols in situ, and then uses the reducing alcohol solution to enhance the efficient leaching of nickel, cobalt, and manganese from black powder.

[0046] In step S5, the efficient leaching process is as follows:

[0047] S501. The separated and recovered liquid organic solvent is added to deionized water at a mass ratio (organic-water mass ratio) of 1:8 to prepare a homogeneous organic-water mixed solution; then, a Ni-containing solution is introduced. 2+ Co 2+ Mn 2+ Transition metal ions (collectively referred to as M) n+ Aqueous solution of M, to regulate M n+ The total concentration was adjusted to 0.06 mol / L; then 10% (mass fraction) dilute sulfuric acid was added to adjust the H₂ concentration in the system. + The concentration was maintained within the range of 0.8 mol / L to construct H. + / M n+ A synergistic dual-catalytic reaction system was established, with a reaction time of 2 hours; in this system, H... + As a Brønsted acid, it protonates the ester group oxygen in the carbonate molecule, weakening the C–O bond and enhancing the electrophilicity of the carbonyl carbon; simultaneously, M n+ As a Lewis acid, it combines with carbonyl oxygen through coordination, further polarizing the C=O bond. The two work synergistically to significantly reduce the activation energy of carbonate hydrolysis; through precise control of H... + With M n+ The concentration ratio is set so that it is in the optimal range of synergistic catalytic activity, which can efficiently promote the directional hydrolysis of carbonate compounds to generate corresponding lower alcohols (such as methanol, ethylene glycol, etc.) and carbon dioxide (or carbonic acid), thereby realizing the deep decomposition and resource conversion of organic solvents.

[0048] S502. The nickel-cobalt-manganese ternary battery black powder slurry (mainly containing Ni, Co, and Mn oxides) is transported to the leaching reactor at a liquid-to-solid ratio (deionized water to black powder mass ratio) of 8:1, and then H2 is added. + / M n+ The reducing lower alcohol solution obtained from the dual-catalytic system is added at 1 / 30 of the total slurry volume. Then, 10% (mass fraction) dilute sulfuric acid is added to adjust the pH to 1–2. The temperature is raised to 90°C and the reduction reaction is maintained at this temperature for 2 hours to obtain a metal salt solution (leaching solution) with stable ionic valence. Under acidic conditions, the lower alcohol generated in situ in the system acts as a reducing agent, selectively removing sparingly soluble high-valence metals (such as Co) from the black powder. 4+ Ni 3+ Mn 4+ ) is reduced to a soluble divalent ion (Co) 2+ Ni 2+ Mn 2+ This process achieves efficient leaching, yielding a leachate rich in target metal ions; simultaneously, alcohols are oxidized into carbon dioxide and water, completing their reduction process and achieving harmless transformation.

[0049] S503. Take a portion of the leachate from step S502 and reuse it in step S501 for use in the formation of H with sulfuric acid. + / M n+ Dual catalytic system.

[0050] In order to effectively reduce the concentration of residual organic matter in the leachate, a method for recycling electrolyte from waste lithium batteries by crushing and recycling the electrolyte and its resource utilization further includes step S6: adding ozone to the leachate in the leaching reactor to decompose the residual organic solvent and reduce the concentration of residual organic matter to less than 500 mg / L.

[0051] In step S3, temperature and pressure sensors can be installed at both the inlet and outlet of the protective gas. The bottom of the material buffer chamber is funnel-shaped, and temperature and pressure sensors are embedded in the middle of the inclined surface at the bottom of the material buffer chamber to acquire the physical parameters of the material in real time. When the temperature of the material is detected to be higher than 50°C, the flow rate of the protective gas at the inlet is increased to reduce the temperature of the closed chamber and the material inside, so that the temperature is stably controlled within the set safe operating range. Pressure sensors are arranged at the inlet, outlet, and inside the material buffer chamber to comprehensively monitor the pressure distribution during the gas flow process in real time. This not only accurately grasps the actual working pressure in the closed chamber, but also determines whether the pipeline is blocked, leaking, or has poor flow by the pressure difference between the inlet / outlet and the chamber. This enables accurate diagnosis, closed-loop control, and safety protection of the airflow state, significantly improving the stability, responsiveness, and reliability of the system.

[0052] The crushing system collects the gas temperature at the inlet / outlet and inside the chamber in real time using temperature sensors, and transmits the measured analog signals (such as voltage, resistance, or current) to the microcontroller. The microcontroller uses a built-in analog-to-digital converter (ADC) or a dedicated signal conditioning circuit to digitize the signal and calculates the actual temperature value (unit: °C or °F) by combining the sensor calibration parameters (such as the resistance-temperature relationship of PT100 or the cold junction compensation algorithm of thermocouples). Subsequently, this temperature data is transmitted via a serial communication interface (such as I...). 2 The gas temperature is transmitted via C, SPI, or UART to a display (such as LCD, OLED, or industrial HMI) to show the real-time value of the current gas temperature, thereby enabling continuous, accurate monitoring and visualization of the gas temperature at the inlet / outlet and inside the chamber.

[0053] In step S4, the heat exchange system includes a compressor, a heat exchanger, and a condenser connected sequentially via pipelines. The compressor's inlet is connected to the protective gas outlet of the crushing system via a pipeline, and the condenser's outlet is connected back to the protective gas inlet of the crushing system via a pipeline, forming a closed-loop circuit. The protective gas discharged from the crushing system is compressed by the compressor into a high-temperature, high-pressure gas, which then enters the heat exchanger. There, it is cooled by heat exchange with an external cold source, forming a low-temperature, high-pressure gas, which is then reinjected into the crushing system for reuse. During the heat exchange process, the organic solvent vapor in the electrolyte is condensed into a liquid state and flows into the condenser for collection. The cold source used in the heat exchanger can be air, circulating cooling water, low-temperature chilled water provided by an ice machine, or an aqueous solution of ethylene glycol. The lower the temperature and the higher the specific heat capacity of the cold source, the stronger its heat transfer capacity and the higher the heat exchange efficiency.

[0054] In addition, an oxygen sensor is installed at the outlet to detect the oxygen concentration there. An external discharge pipe is connected between the compressor and the outlet, with its outlet end connected to the activated carbon adsorber. An external discharge valve is installed on the external discharge pipe to open and close it. A circulation valve is installed on the compressor side of the pipe between the compressor and the outlet. When the oxygen sensor at the outlet detects an oxygen concentration greater than 1% in the protective gas, the circulation valve is closed, and the external discharge valve is opened, allowing the protective gas with an oxygen concentration greater than 1% to enter the activated carbon adsorber through the external discharge pipe. The activated carbon adsorber absorbs the small amount of volatile organic compounds in the protective gas and then discharges it into the atmosphere through the outlet end of the activated carbon adsorber. Furthermore, the discharge of protective gas inevitably disrupts the pressure balance of the protective gas circulation system, necessitating the injection of an equal amount of fresh gas. Therefore, to achieve this, a fresh protective gas storage tank is added. The outlet of this tank is equipped with a replenishment valve, and the pipeline between the condenser and the inlet is connected to the outlet of the replenishment valve. When the protective gas is discharged through the activated carbon adsorber, the replenishment valve is opened, injecting fresh protective gas into the crushing system through the storage tank to maintain pressure balance within the system. When the oxygen sensor at the outlet detects that the oxygen concentration in the protective gas is less than 1%, both the replenishment valve and the discharge valve are closed, while the circulation valve is opened, allowing the protective gas to be recycled through the heat exchange system. The entire process can be completed during crushing operations without stopping the machine.

[0055] The crushing system uses an oxygen sensor to collect the oxygen concentration at the outlet in real time, transmitting the output analog signal (such as voltage or current) to the microcontroller. The microcontroller's built-in analog-to-digital converter (ADC) digitizes the signal and, combined with pre-stored calibration curves and temperature compensation algorithms, converts the raw data into an accurate oxygen concentration value (unit: %vol O2). Subsequently, the microcontroller communicates via a serial communication interface (such as SPI, I...). 2The oxygen concentration is sent to a display (such as an LCD, OLED, or industrial touchscreen) via a C or UART to provide a real-time, intuitive display.

[0056] In step S501, carbonate compounds (such as EC, DMC, EMC) in the electrolyte undergo acid-catalyzed hydrolysis under dilute sulfuric acid and heating, and are converted into H+. + With M n+ As a catalyst, it generates corresponding lower alcohols (such as methanol, ethanol, and ethylene glycol) and carbon dioxide.

[0057] Example of a reaction formula:

[0058]

[0059]

[0060]

[0061] The resulting alcohols possess strong reducing power, undergoing redox reactions with high-valence metal oxides in acidic environments. They are oxidized to CO2 and H2O, while simultaneously reducing Ni... 3+ / Ni 4+ Co 3+ / Co 4+ Mn 4+ When reduced to Ni 2+ Co 2+ Mn 2+ .

[0062] Example of a reaction (using methanol as an example):

[0063]

[0064]

[0065] (M is a single substance or mixture of Ni, Co, and Mn)

[0066] In step S6, ozone can effectively and deeply oxidize the trace organic matter remaining in the leachate (such as unreacted alcohols, ester intermediates, etc.), completely degrade and mineralize it into carbon dioxide and water, thereby significantly reducing the chemical oxygen demand (COD) of the leachate, creating a cleaner reaction environment for subsequent metal separation and purification processes, and thus improving the recovery efficiency of the target metal and the purity of the final product.

[0067]

[0068]

[0069]

[0070] Example 2

[0071] The difference from Example 1 is that in step S501: the separated and recovered liquid organic solvent is added to deionized water at a mass ratio of 1:5 to prepare a homogeneous organic-water mixed solution; subsequently, a Ni-containing solution is introduced. 2+ Co 2+ Mn 2+ Transition metal ions (collectively referred to as M) n+ Aqueous solution of M, to regulate M n+ The total concentration was adjusted to 0.02 mol / L; then 6% (mass fraction) dilute sulfuric acid was added to adjust the H₂ concentration in the system. + The concentration was maintained within the range of 0.25 mol / L to construct H. + / M n+ The synergistic dual-catalytic reaction system had a reaction time of 2 hours.

[0072] Step S502: The nickel-cobalt-manganese ternary battery black powder slurry (mainly containing Ni, Co, and Mn oxides) is transported to the leaching reactor at a liquid-to-solid ratio (deionized water to black powder mass ratio) of 2.5:1, and then H2 is added. + / M n+ The amount of the reducing lower alcohol solution obtained by the dual-catalytic system is 1 / 30 of the total slurry by mass; then 6% (mass fraction) of dilute sulfuric acid is added to adjust the pH of the system to 1–2; the temperature is raised to 60°C and the reduction reaction is carried out at a constant temperature for 2 hours to obtain a metal salt solution with stable ionic valence.

[0073] Example 3

[0074] The difference from Example 1 is that in step S501: the separated and recovered liquid organic solvent is added to deionized water at a mass ratio of 1:10 to prepare a homogeneous organic-water mixed solution; subsequently, a Ni-containing solution is introduced. 2+ Co 2+ Mn 2+ Transition metal ions (collectively referred to as M) n+ Aqueous solution of M, to regulate M n+ The total concentration was adjusted to 0.1 mol / L; then 13% (mass fraction) dilute sulfuric acid was added to adjust the H₂ concentration in the system. + The concentration was maintained within the range of 1.0 mol / L to construct H. + / M n+ The synergistic dual-catalytic reaction system had a reaction time of 2 hours.

[0075] Step S502: The nickel-cobalt-manganese ternary battery black powder slurry (mainly containing Ni, Co, and Mn oxides) is transported to the leaching reactor at a liquid-to-solid ratio (deionized water to black powder mass ratio) of 10:1, and then H2 is added. + / M n+ The amount of the reducing lower alcohol solution obtained by the dual-catalytic system is 1 / 30 of the total slurry by mass; then 13% (mass fraction) of dilute sulfuric acid is added to adjust the pH of the system to 1–2; the temperature is raised to 80°C and the reduction reaction is carried out at a constant temperature for 2 hours to obtain a metal salt solution with stable ionic valence state.

[0076] Comparative Example 1

[0077] The difference from Example 1 is that in step S502, the nickel-cobalt-manganese ternary battery black powder slurry (mainly containing Ni, Co, and Mn oxides) is transported to the leaching reactor at a liquid-to-solid ratio (mass ratio of deionized water to black powder) of 1:1.

[0078] Comparative Example 2

[0079] The difference from Example 1 is that in step S502, the nickel-cobalt-manganese ternary battery black powder slurry (mainly containing Ni, Co, and Mn oxides) is transported to the leaching reactor at a liquid-to-solid ratio (mass ratio of deionized water to black powder) of 15:1.

[0080] Comparative Example 3

[0081] The difference from Example 1 is that in step S5, the concentration of dilute sulfuric acid is 3%.

[0082] Comparative Example 4

[0083] The difference from Example 1 is that in step S5, the concentration of dilute sulfuric acid is 20%.

[0084] Comparative Example 5

[0085] The difference from Example 1 is that in step 502, the temperature is raised to 100°C and the reduction reaction is carried out at a constant temperature for 1.5 hours.

[0086] Comparative Example 6

[0087] The difference from Example 1 is that in step 502, the temperature is raised to 40°C and the reduction reaction is carried out at a constant temperature for 3 hours.

[0088] Comparative Example 7

[0089] The difference from Example 1 is that in step 501, the organic-to-water mass ratio is 1:3.

[0090] Comparative Example 8

[0091] The difference from Example 1 is that in step 501, the organic-to-water mass ratio is 1:15.

[0092] Comparative Example 9

[0093] The difference from Example 1 is that in step 501, a Ni-containing substance is introduced.2+ Co 2+ Mn 2+ Transition metal ions (collectively referred to as M) n+ Aqueous solution of M, to regulate M n+ The total concentration was reduced to 0.01 mol / L.

[0094] Comparative Example 10

[0095] The difference from Example 1 is that in step 501, a Ni-containing substance is introduced. 2+ Co 2+ Mn 2+ Transition metal ions (collectively referred to as M) n+ Aqueous solution of M, to regulate M n+ The total concentration was reduced to 0.2 mol / L.

[0096] Comparative Example 11

[0097] The difference from Example 1 is that step S5 does not construct H. + / M n+ Instead of a dual-catalytic system, a nickel-cobalt-manganese ternary battery black powder slurry (mainly composed of Ni, Co, and Mn oxides) is transported to a leaching reactor. The liquid-to-solid ratio (mass ratio of deionized water to black powder) in the slurry is 8:1. Subsequently, a separated and recovered liquid organic solvent and a 10% concentration of dilute sulfuric acid are added to the leaching reactor. The amount of liquid organic solvent added (by mass) is 1 / 30 of the slurry. The pH value is controlled at 1-2 using dilute sulfuric acid. The mixture is heated to 90°C for a reduction reaction for 6 hours, ultimately obtaining a metal salt solution with stable ionic valence (leaching solution). Under heating and acidic conditions, the organic solvent undergoes acid-catalyzed hydrolysis, converting into corresponding lower alcohols (such as methanol, ethanol, ethylene glycol, etc.) and releasing carbon dioxide. These in-situ generated lower alcohols act as reducing agents in the acidic medium, undergoing a redox reaction with the higher valence metal oxides. They themselves are oxidized to carbon dioxide and water, while Ni is also oxidized. 3+ / Ni 4+ Co 3+ / Co 4+ Mn 4+ Reduced to soluble Ni 2+ Co 2+ Mn 2+ This enables highly selective leaching of the target metal.

[0098] Comparative Example 12

[0099] The difference from Comparative Example 11 is that the reduction reaction was carried out at 60°C for 8 hours, and a metal salt solution with stable ionic valence state (leaching solution) was finally obtained.

[0100] Comparative Example 13

[0101] The difference from Comparative Example 1 is that, in step S5, sulfur dioxide from the prior art is used instead of H2O. + / M n+ The solution containing reducing lower alcohols obtained from the conversion of the dual-catalytic system.

[0102] In Examples 1-3 and Comparative Examples 1-13, the amount of deionized water added to the slurry was 1000 kg.

[0103] The specific parameters of Embodiments 1-3 and Comparative Examples 1-13 of the present invention are shown in Table 1.

[0104] Table 1

[0105]

[0106] Performance testing

[0107] (1) Calculation of leaching rate of nickel, cobalt, manganese and lithium

[0108] Let the mass (dry) of black powder be W (kg), the metal grade be R (%), the volume of leachate be V (L), the metal concentration be C (kg / L), and the mass (dry) of the leaching residue be W. r (kg), slag grade R r (%), then the metal leaching rate η is:

[0109]

[0110] Metal content was tested using ICP-MS (inductively coupled plasma mass spectrometry).

[0111] Test results: The performance test results are shown in Table 2.

[0112] Table 2

[0113]

[0114] According to the data in Table 1, Examples 1-3 of this invention demonstrate that the various process parameters work together to achieve a synergistic effect, with the absence of any one parameter weakening the overall effect. Examples 1-3 of this invention simultaneously recover the electrolyte through charged crushing under a protective atmosphere, and then process the resulting carbonate organic solvent in H... + / Ni 2+ -Co 2+ -Mn 2+In the dual-catalytic system, high temperature and high pressure are used to convert the electrolyte into a reducing lower alcohol in situ. The alcohol solution is then used as a green reducing agent to efficiently leach nickel, cobalt, and manganese from ternary black powder, realizing the resource utilization of the electrolyte and further improving the leachation rate of nickel, cobalt, manganese, and lithium. The leachation rates of nickel, cobalt, and lithium can all exceed 99%, and the leachation rate of manganese can all exceed 98%. At the same time, part of the leachate is recycled into the catalytic system, forming an internal circulation of metal ions, eliminating the need for traditional external reducing agents such as hydrogen peroxide, and significantly improving the safety, economy, and sustainability of the process.

[0115] Analysis of Example 1 and Comparative Examples 1-2 shows that the leaching rate of nickel-cobalt-manganese-lithium in Comparative Example 1 is significantly reduced, with the highest leaching rate of metal ions not exceeding 20%. This is because the slurry is viscous and has poor fluidity, preventing the acid and reducing agent from fully contacting the solid particles, resulting in incomplete reduction of high-valence metals and a decrease in leaching rate. The leaching rate of nickel-cobalt-manganese-lithium in Comparative Example 2 also decreased, but it was higher than that of Comparative Example 1. This is because the liquid-to-solid ratio of the black powder slurry was too high (i.e., the solid content was too low), resulting in a significant reduction in the amount of black powder per unit volume, leading to a low concentration of reactants (high-valence metal oxides), which in turn reduces the overall metal leaching amount (i.e., the overall reaction rate), characterized by a decrease in leaching rate.

[0116] Analysis of Example 1 and Comparative Examples 3-4 shows that, in Comparative Example 3, 3% dilute sulfuric acid was added, so if H+ is to be added... + Maintaining a constant final concentration requires increasing the amount of dilute sulfuric acid added, which introduces a large amount of extra water, diluting the organic solvent concentration, reducing the hydrolysis and reduction reaction rates, and ultimately decreasing the leaching rate of nickel, cobalt, manganese, and lithium within the set time. Comparative Example 4, by adding 20% ​​dilute sulfuric acid, reduces the amount of water introduced, but if mixing is insufficient during addition, a transiently high-acidity environment can easily form in localized areas; as the reaction proceeds or the system is diluted, the pH in these areas may fluctuate rapidly, reaching Fe in micro-regions. 3+ Al 3+ The hydrolysis threshold of impurity ions promotes the formation of hydroxide colloids or amorphous precipitates. These colloids easily adsorb and encapsulate incompletely reacted black powder particles or target metal oxides, hindering the diffusion of acid and reducing agents into the particle interior, thereby inhibiting the effective reduction and dissolution of high-valence metal ions such as Ni, Co, and Mn, ultimately leading to a decrease in metal leaching rate.

[0117] Analysis of Example 1 and Comparative Examples 5-6 shows that when the reduction reaction temperature reaches 100℃, although the reduction reaction time is shortened, lower alcohols (such as methanol, ethylene glycol, etc.) are prone to deep oxidation in a high-temperature, strongly acidic environment, generating not only CO2 and H2O, but also byproducts such as formic acid, acetaldehyde, and oxalic acid. These side reactions consume the effective reducing agent, weakening its effect on high-valence metals (such as Co). 4+ Ni 3+ Mn 4+The selective reduction capability of the acid leaching process leads to a decrease in the metal leaching rate. When the reduction reaction temperature is lowered to 40℃, although the reduction reaction time is prolonged, the rate of carbonate hydrolysis to generate reducing alcohols is significantly inhibited, and the reducing ability of lower alcohols to reduce high-valence nickel, cobalt, and manganese in the black powder is weakened, making it difficult for metal oxides to be effectively converted into soluble divalent ions. At the same time, the acid leaching and reduction kinetics are slow, and a passivation layer is easily formed on the particle surface, resulting in a significant decrease in the leaching rate of nickel, cobalt, manganese, and lithium, and a prolonged reaction cycle, which seriously affects the leaching rate of metals such as nickel, cobalt, and manganese.

[0118] Analysis of Example 1 and Comparative Examples 7-8 shows that when the organic-water mass ratio is reduced to 1:3, the amount of water in the system is insufficient to support the complete hydrolysis reaction of carbonate compounds, resulting in insufficient formation of reducing lower alcohols. Simultaneously, a high organic phase ratio reduces the system's polarity, potentially leading to the reaction of dilute sulfuric acid and transition metal ions (M...). n+ Uneven dissolution or localized precipitation can damage H+. + / M n+ The homogeneous environment required for co-catalysis not only weakens catalytic efficiency but also hinders subsequent use for reducing high-valent metals (such as Co) in black powder. 4+ Ni 3+ Mn 4+ The low concentration of the reducing agent resulted in insufficient reduction, significantly reducing the leaching rates of target metals such as nickel, cobalt, manganese, and lithium. When the organic-to-water mass ratio increased to 1:15, although the water volume was sufficient, the organic solvent was excessively diluted, leading to a low concentration of hydrolyzable substrate per unit volume. This resulted in a reduced total amount of reducing alcohols and their dispersed distribution. Even with H... + and M n+ As the concentration is maintained, its "effective catalytic density" relative to the substrate decreases, and the hydrolysis reaction rate slows down. As a result, the supply of reducing agent is insufficient or the release is slow, making it impossible to complete the effective reduction of high-valence metals within the set time. This also causes sluggish metal leaching kinetics, ultimately reducing the overall leaching rate.

[0119] Analysis of Example 1 and Comparative Examples 9-10 shows that when M n+ When the total concentration is reduced to 0.01 mol / L, there are insufficient Lewis acid sites in the system, which cannot effectively coordinate with the carbonyl oxygen in the carbonate molecule. This results in insufficient polarization of the C=O bond, making it difficult to react with H+. + The protonation process forms a highly efficient synergy; the carbonate hydrolysis rate decreases significantly, and the formation of reducing lower alcohols is slow and in small quantities, resulting in insufficient subsequent reduction of high-valence nickel, cobalt, and manganese in the black powder, leading to a low metal leaching rate. When M n+ While increasing the total concentration to 0.2 mol / L can enhance the activation of Lewis acids, excessive metal ions may trigger side reactions, such as promoting excessive oxidation of alcohols or catalyzing the polymerization of organic compounds. Simultaneously, high concentrations of M...n+ (especially containing Fe) 3+ Al 3+ When impurities are present, the carbon dioxide is easily hydrolyzed under local pH fluctuations to form colloids or precipitates, which can encapsulate black powder particles or block pores, hindering the diffusion of acid and reducing agent. In addition, excess metal ions may competitively adsorb onto active sites, which can inhibit the directional hydrolysis of the target carbonate, ultimately reducing the reduction efficiency and metal leaching rate.

[0120] Analysis of Example 1 and Comparative Examples 11-12 shows that if H is not constructed... + / M n+ A synergistic dual-catalytic system was used, but when nickel-cobalt-manganese ternary battery black powder slurry, dilute sulfuric acid, and recovered liquid organic solvent were directly mixed and reacted, even with optimized reaction temperature and time, the metal leaching rate was still significantly lower than that using H2O. + / M n+ In the case of a dual-catalytic system. This is because in the absence of M... n+ Under the synergistic effect of Lewis acids, carbonate organic solvents are unable to efficiently hydrolyze to generate sufficient reducing lower alcohols, resulting in insufficient in-situ reducing agent supply within the system, which fails to effectively remove the poorly soluble high-valence Co from the black powder. 4+ Ni 3+ Mn 4+ The metal is reduced to soluble divalent ions, which limits the overall leaching kinetics and the final metal recovery efficiency.

[0121] Analysis of Example 1 and Comparative Example 13 shows that although sulfur dioxide (SO2) is a highly efficient exogenous reducing agent, capable of reducing high-valence metals to soluble divalent ions under acidic conditions, its reduction process is intense and the local reaction is concentrated, easily leading to rapid passivation of the black powder particle surface or the formation of a dense product layer, hindering the diffusion of acid and reducing agent inward. H... + / M n+ The dual-catalytic system generates lower alcohol reducing agents in situ and through slow release, achieving a mild and continuous reducing environment, which is more conducive to the uniform and complete dissolution of high-valent metals; furthermore, M in this system n+ It can participate in the catalytic cycle and partially enter the solution, synergistically interacting with the target metal to further promote reaction kinetics. Therefore, even with SO2, its metal leaching rate is still slightly lower than that of H2. + / M n+ Dual catalytic system.

[0122] The above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit it. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure, and they should all be covered within the scope of the claims and specification of this disclosure.

Claims

1. A method for recycling electrolyte from waste lithium batteries by electrically crushing, characterized in that, It comprises the following steps: S1, close the valve plate between the buffer tank and the crusher in the crushing system and the discharge port valve, open the feed inlet valve and put in the waste lithium battery to be treated, immediately close the feed inlet valve after feeding to form a closed chamber; S2, the protective gas is introduced into the material buffer bin from the air inlet of the crushing system, and the crusher is started to run; S3, open the valve plate between the buffer tank and the crusher, so that the waste lithium battery to be treated enters the crusher, and the waste lithium battery is broken into flaky material after being broken by the crusher; S4, when the waste lithium battery is crushed, the organic solvent in the electrolyte is volatilized by shearing and temperature rise, and mixed with the protective gas to form a mixed gas; the mixed gas enters the heat exchange system through the gas outlet, and the organic solvent is condensed into liquid after cooling and separated and collected through the condenser, and the protective gas is low-temperature reflux and recycled; S5, by constructing H + / M n+ The application discloses a double-catalytic system for in-situ conversion of carbonate compounds in liquid organic solvents into reductive alcohols, and reuses the reductive alcohol solution to intensify high-efficiency leaching of nickel, cobalt and manganese in black powder.

2. The waste lithium battery crushing and recycling electrolyte and resource utilization method according to claim 1, wherein: In step S5, the high-efficiency leaching step is as follows: S501. The separated and recovered liquid organic solvent is added to deionized water at a mass ratio of 1:(5~10) to prepare a homogeneous organic-water mixed solution; then, a solution containing M is introduced. n+ Aqueous solutions of transition metal ions regulate M n+ Adjust the total concentration to 0.02–0.1 mol / L; then add dilute sulfuric acid with a concentration of 6–13% to adjust the H₂ concentration in the system. + The concentration was maintained in the range of 0.25–1.0 mol / L to construct H + / M n+ The synergistic dual-catalytic reaction system had a reaction time of 2 hours. S502, The nickel-cobalt-manganese ternary battery black powder slurry is fed to the leaching reactor at a liquid-to-solid ratio of (2.5~10):1; then, H-processed black powder slurry is added. + / M n+ The amount of the reducing lower alcohol solution obtained by the dual-catalytic system is 1 / 30 of the total slurry by mass; then, dilute sulfuric acid with a concentration of 6-13% is added to adjust the pH of the system to 1-2; the temperature is raised to 60-90°C and the reduction reaction is carried out at a constant temperature for 2 hours to obtain a leachate with stable ionic valence state.

3. The waste lithium battery crushing and recycling electrolyte and resource utilization method according to claim 2, wherein: In step S5, the leaching liquid is also reused, as follows: S503, take part of the leaching solution in step S502 back to step S501 for constructing H + / M n+ Dual catalytic system, regulating M n+ Total concentration to 0.02-0.1 mol / L.

4. The waste lithium battery crushing and recycling electrolyte and resource utilization method according to claim 1, wherein: In step S1, the crushing system is composed of a battery feed inlet, a feed inlet valve, a buffer tank, a valve plate, a crusher, a material buffer bin and a discharge port valve from top to bottom, and the feed inlet valve and the discharge port valve are closed to form a closed chamber between the feed inlet valve and the discharge port valve; The side wall of the material buffer bin is provided with an air inlet, and the buffer tank is provided with a gas outlet; When the protective gas is introduced into the crushing system, the protective gas enters the material buffer bin from the air inlet, and the air between the feed inlet valve and the discharge port valve is discharged from the gas outlet of the buffer tank, so that the space between the feed inlet valve and the discharge port valve is in a protective gas atmosphere.

5. The waste lithium battery crushing and recycling electrolyte and resource utilization method according to claim 1, wherein: In step S2, the protective gas is selected from one or more of nitrogen, argon and carbon dioxide.

6. The waste lithium battery crushing and recycling electrolyte and resource utilization method according to claim 1, wherein: In step S4, the heat exchange system comprises a compressor, a heat exchanger and a condenser connected in sequence by pipelines; the air inlet of the compressor is connected with the protective gas outlet of the crushing system through a pipeline, and the gas outlet of the condenser is connected with the protective gas inlet of the crushing system through a pipeline, forming a closed circulation loop.

7. The waste lithium battery crushing and recycling electrolyte and resource utilization method according to claim 6, wherein: The heat exchange system further comprises an oxygen sensor, an activated carbon adsorber and a fresh protective gas tank; an exhaust branch is arranged on the pipeline between the compressor and the gas outlet of the crushing system, the outlet of the exhaust branch is connected to the activated carbon adsorber, and an exhaust valve is arranged on the exhaust branch; a circulation valve is arranged on the main gas path near the compressor, for controlling the gas backflow; The outlet of the fresh protective gas tank is provided with a supplement valve, and the gas outlet end of the supplement valve is communicated with the gas supply pipeline between the condenser tank and the gas inlet of the crushing system through a pipeline, for supplementing high-purity protective gas when the pressure in the closed chamber is insufficient or the oxygen content exceeds the standard, so as to ensure that the entire crushing process is always in a safe and inert oxygen-free environment.

8. The method according to claim 1, wherein: After the step S5, further comprising deep treatment of residual trace organic matter in the leaching solution, as follows: S6, adding ozone to the leaching solution in the leaching reactor to decompose the residual organic solvent, and reducing the concentration of residual organic matter to less than 500 mg / L.

9. The method according to claim 1, wherein: In the step S4, the temperature in the closed chamber is controlled below 50 DEG C.

10. The method according to claim 1, wherein: In the step S3, the pressure in the closed chamber is 0.09-0.1 MPa.

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