Method and device for stripping and recycling active materials from waste batteries

Abstract

The application discloses a stripping method of waste battery electrode sheet. The mixed system containing waste battery electrode sheet and aqueous solvent is stripped under the assistance of ultrasonic and ozone to separate the current collector and electrode active material in the electrode sheet. The application also includes a scheme for deeply removing impurities from the stripped electrode material. The battery positive electrode active material is obtained by removing aluminum through alkali leaching, removing fluorine through shearing and ozone, and degrading residual electrolyte to obtain high-purity positive electrode active material. The negative electrode active material can be obtained by removing copper through acid leaching and removing residual organic electrolyte through ozone oxidation. The fluorine-containing and lithium-containing solution generated in the fluorine-removing process is converted into stable precipitate by adding a fluorine-removing agent, thereby effectively avoiding the generation of harmful fluorine-containing gas; the slightly soluble LiF is converted into a lithium salt solution with a larger solubility, and then Li2CO3 product is obtained through carbonization and decarburization reaction. The application also relates to a device capable of achieving the above purposes.

Description

Technical Field

[0001] This invention belongs to the field of waste battery recycling, specifically involving the stripping and recycling of battery active materials. Background Technology

[0002] The stripping of active battery materials is a technical bottleneck and a key step in the recycling of spent lithium-ion batteries. Generally, the adhesion between the negative electrode material and the current collector gradually weakens with prolonged use, so the active material can be separated from the current collector using simple mechanical force. However, the positive electrode material is tightly bonded to the aluminum foil using adhesives such as polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTEF), making it difficult to achieve good separation results using simple physical methods.

[0003] Currently, electrode material separation technologies mainly include solvent dissolution, thermal treatment, and mechanical-physical methods. Solvent dissolution includes organic solvent immersion and alkaline immersion. Organic solvent methods are based on the principle of "like dissolves like," using organic solvents such as N-methylpyrrolidone (NMP), dimethylformamide (DMF), and ethanol to dissolve the binder, thereby removing the active material. Alkaline immersion involves dissolving the current collector (aluminum foil) in an alkaline solution to obtain an aluminum-containing solution and the active material. Solvent dissolution effectively avoids the emission of toxic fumes; however, organic solvents are generally expensive and have a certain degree of toxicity, posing a significant threat to the occupational health of operators. While alkaline solutions are less toxic, they produce large amounts of aluminum-containing solution, which is detrimental to subsequent impurity removal. Thermal treatment is low-cost and simple to operate, making it one of the most widely used technologies in the industry. This method decomposes the binder in the electrode material at high temperatures, thereby removing the active material. However, organic materials such as PVDF produce large amounts of toxic gases during pyrolysis, and their environmental pollution needs further evaluation and investigation. Furthermore, the binder (PVDF) and electrolyte (LiPF6) generate a large amount of sulfur-containing gas during pyrolysis, which not only pollutes the environment and corrodes equipment, but also reacts with aluminum foil and LiFePO4 to form AlF3, LiAlPO4, and AlPO4. AlF3 is a very stable precipitate, insoluble in acids and alkalis and possessing good thermal stability, making it difficult to remove effectively once formed. Additionally, the relatively stable valence of Al leads to a significant performance degradation in the resulting lithium-ion batteries due to the formation of LiAlPO4 and AlPO4. The mechanical-physical method involves mechanically crushing the components of waste lithium-ion batteries to achieve initial separation, followed by ball milling, sieving, and flotation to obtain relatively pure electrode active materials. This method is simple to operate and easily industrialized, but the resulting electrode products have high copper and aluminum content, making subsequent impurity removal difficult. Moreover, this method does not effectively treat organic matter, requiring further processing.

[0004] In summary, current technologies for separating active materials from spent lithium-ion batteries suffer from high production costs, severe environmental pollution, and low product performance, becoming a technological bottleneck restricting the green and efficient recycling of spent lithium-ion batteries. There is an urgent need in this field to develop a green, environmentally friendly, and efficient active material separation technology and apparatus to achieve efficient and clean pretreatment of active materials from spent lithium-ion batteries. Summary of the Invention

[0005] To address the problems of low efficiency, high cost, and difficulty in controlling the quality of peeled products in existing electrode stripping methods, the primary objective of this invention is to provide a method for peeling electrode sheets from waste batteries, aiming to achieve in-situ non-destructive peeling of active materials from waste batteries, thereby improving peeling efficiency and reducing processing costs.

[0006] The second objective of this invention is to provide a method for recycling and purifying electrode materials from used battery electrode sheets, aiming to obtain high-purity electrode materials with low current collector, low fluorine, and low organic residue from the electrode sheets.

[0007] The present invention also includes equipment capable of stripping and recycling the electrode sheets of the waste batteries.

[0008] A method for peeling off electrode sheets from waste batteries involves peeling off a mixture containing waste battery electrode sheets and an aqueous solvent under ultrasonic and ozone-assisted conditions to separate the current collector and electrode material from the electrode sheets.

[0009] This invention innovatively demonstrates that an ultrasonic-ozone-assisted stripping process can achieve rapid separation of battery active materials from the current collector at room temperature while ensuring the integrity of the current collector. The chemical structure of the stripped active material remains stable, which is highly beneficial for subsequent recycling or remediation. Furthermore, during the stripping process, only trace amounts of the current collector are mixed into the active material in the form of debris, which can be easily removed by simple acid-base treatment.

[0010] The stripping process described in this invention has excellent versatility, especially for electrode sheets containing hydrophobic binders such as PVDF, where it still achieves excellent stripping efficiency and effect in aqueous systems. Furthermore, the method of this invention eliminates the need for electrode sheet crushing, thus simplifying the processing and enabling better recycling of the current collector.

[0011] In this invention, the waste battery electrode sheet is an electrode sheet obtained by disassembling and separating waste lithium-ion batteries.

[0012] In this invention, there are no special requirements regarding the type of waste lithium-ion batteries.

[0013] In this invention, the electrode plates include positive electrode plates and / or negative electrode plates.

[0014] In this invention, the positive electrode sheet may include a positive current collector (such as an Al foil) and a positive electrode material composited on its surface. The positive electrode material includes a positive electrode active material, a binder, and a conductive agent. The positive electrode active material is not particularly required; for example, it may be at least one of LiMPO4 and LiNO2. M may be Fe or Mn, and N may be at least one of Ni, Mn, and Co. The binder may be a water-soluble or water-insoluble binder, such as PVDF.

[0015] In this invention, the negative electrode sheet includes a negative electrode current collector (such as Cu foil) and a negative electrode material composited on its surface. The negative electrode material includes a negative electrode active material, a binder, and a conductive agent. The negative electrode active material includes at least one of carbon-based active materials, silicon-based active materials, and silicon-carbon composite materials. The carbon-based active material can be, for example, graphite. The binder can be a water-soluble or water-insoluble binder, such as CMC.

[0016] In this invention, the electrode sheets can be pre-cut as needed before being peeled off.

[0017] In this invention, the positive and negative electrode plates in the electrode sheet can be peeled off separately or together.

[0018] In this invention, the aqueous solvent is water, or a mixture of water and an organic solvent; the organic solvent is a solvent that is miscible with water and cannot be decomposed by ozone.

[0019] In this invention, the liquid-solid ratio of the electrode sheet to the aqueous solvent can be controlled as needed, and considering the processing cost, it can be further set to 1-10 mL / g.

[0020] In this invention, an ozone-containing atmosphere is introduced into the mixture, and the stripping is performed under ultrasonic assistance.

[0021] In this invention, the ultrasonic and ozone-assisted gas-solid-liquid three-phase reaction treatment helps to significantly improve the peeling efficiency and effect.

[0022] Preferably, the concentration of ozone in the ozone-containing atmosphere is 1 vol.% or higher;

[0023] In this invention, the ozone injection rate can be adjusted according to needs, preparation scale, and efficiency. Considering processing costs, it can be 0.5-10 times the theoretical amount, and more preferably 3-10 times. The theoretical amount refers to the theoretical amount of ozone required to oxidize the binder in the electrode sheet.

[0024] Its selectable flow rate can be above 10 mL / min, further above 100 mL / min, and even further up to 100 to 100,000 mL / min.

[0025] Preferably, the ultrasonic power is 50–500W, more preferably 80–200W. In this invention, at the aforementioned power levels, the synergistic effect of ultrasound and ozone can be further improved, which helps to further synergistically improve the peeling efficiency and effect.

[0026] In this invention, the temperature during the peeling process is above 0°C, for example, it can be 0 to 100°C, and considering the convenience of process operation, it can be further set to 15 to 40°C;

[0027] In this invention, there are no special requirements for the peeling time. The peeling process takes more than 5 minutes. However, considering the excellent synergistic peeling efficiency of the process in this invention, the peeling time can be controlled between 10 and 90 minutes to achieve the desired technical efficiency.

[0028] In this invention, the stripping method can be implemented using existing ultrasonic equipment.

[0029] This invention also provides a method for recycling and purifying electrode materials from waste battery electrode sheets. The method described in this invention is used to obtain crude electrode material. The crude electrode material is then subjected to deep current collector removal treatment to obtain a first-stage processed material. This first-stage processed material is then slurried and subjected to shear ozone-assisted defluorination treatment to obtain purified electrode material.

[0030] In this invention, the crude electrode material obtained by stripping can be subjected to a deep current collector removal process based on known techniques. For example, the deep current collector removal process can be carried out by acid treatment or alkali treatment.

[0031] In this invention, when the electrode material includes a positive electrode material, the deep current collector removal process is an alkaline treatment. The operation steps are, for example, as follows: the crude positive electrode material obtained from the stripping is placed in an alkaline solution for alkaline treatment, followed by solid-liquid separation to obtain a processed material. The alkaline solution is, for example, an aqueous solution of an alkali metal hydroxide.

[0032] In this invention, when the electrode material includes a negative electrode material, the deep current collector removal process is performed by acid treatment. The operation steps are, for example, as follows: the crude negative electrode material obtained from the stripping is placed in an acid solution for acid treatment, followed by solid-liquid separation to obtain a processed material. The acid solution is, for example, an aqueous solution of at least one of hydrochloric acid, sulfuric acid, and nitric acid.

[0033] In this invention, the crude electrode material is first subjected to deep defluorination treatment, followed by defluorination using a shear-ozone method. The shearing method enables sufficient mass transfer and reaction of the three-phase reaction of gas (ozone), liquid (solution phase), and solid (organic matter), improving the deep defluorination effect and helping to obtain high-quality electrode material.

[0034] In this invention, the solvent used in the slurry processing is an aqueous solvent. Considering the composition of the process and the reduction of three wastes, it can be the mother liquor after solid-liquid separation after stripping.

[0035] In this invention, the content of the first-stage treatment material in the slurry of the first-stage treatment material pulping can be adjusted as needed, for example, it can be 3 to 5 g / mL.

[0036] In this invention, a shearing ozone-assisted defluorination treatment is innovatively applied to a section of the material, thereby achieving a deep defluorination effect.

[0037] In this invention, the shear-assisted ozone treatment refers to a process in which a slurry containing a section of treatment material and ozone are mixed and reacted using a shear mixing device. The shear mixing device can be any equipment known in the industry that can achieve shear mixing via shearing.

[0038] In this invention, during the ozone-assisted defluorination process, the reaction system (slurry) can be circulated into a shear mixing device and ozone shear mixing for cyclic processing.

[0039] In this invention, during the circulation process, the slurry circulation input end is located near the slurry surface. The slurry circulation output end is located above and / or below the slurry surface (preferably at the bottom of the slurry). The circulation method described in this invention can be understood as an top-entry circulation type.

[0040] In this invention, the input end is positioned as close as possible to the slurry surface while ensuring slurry circulation. Preferably, the distance between the input end and the slurry surface is within 5 cm, and more preferably within 2 cm. Studies have shown that this circulation method can further improve process synergy and contribute to improving the deep defluorination effect.

[0041] In this invention, the bottom of the slurry can specifically be a region that is more than 10 cm away from the liquid surface.

[0042] In this invention, the slurry is circulated, and this is combined with the aforementioned top-entry circulation method to achieve a deep defluorination effect.

[0043] In this invention, the ozone injection rate in the ozone-assisted defluorination stage is 1 to 10 times the theoretical amount, more preferably 2 to 5 times; the theoretical amount refers to the theoretical amount required to completely convert the organic fluorine-containing components in the system into inorganic fluorine. The flow rate can be adjusted as needed, for example, above 10 mL / min, more preferably above 100 mL / min, and even further, from 100 to 100,000 mL / min.

[0044] Preferably, the shear rate of the ozone-assisted defluorination treatment stage is 1000–6000 r / min;

[0045] Preferably, the reaction temperature of the ozone-assisted defluorination treatment stage is 20–60°C;

[0046] Preferably, the reaction time of the ozone-assisted defluorination treatment stage is >30 min;

[0047] Preferably, after the ozone-assisted defluorination treatment is completed, solid-liquid separation is performed to obtain purified electrode materials and fluorine-containing and lithium-containing waste liquids respectively; after the above-mentioned fluorine-containing and lithium-containing waste liquids are defluorinated by a defluorinating agent, fluoride precipitates and lithium-containing solutions are obtained respectively.

[0048] In this invention, the stripping process can be implemented using conventional equipment with ultrasonic capabilities, and the shearing ozone treatment process can also be implemented using conventional shearing gas-liquid mixing equipment.

[0049] In order to make the technical solution better applicable to industry, the present invention also designed a highly integrated waste battery electrode stripping and recycling purification device that is conducive to industrial application and can implement the recycling and purification method. The device includes a box, which is provided with an inlet, an outlet (10) and a reaction zone. The inlet is provided with a feeding bin (2) and a feeding motor (1), and the outlet is provided with a current collector unloading belt (11). The box is provided with a conveying mechanism that passes through the inlet, the reaction zone and the outlet in sequence.

[0050] The reaction zone contains a liquid phase reaction system. The bottom of the reaction zone is provided with an active material discharge port (13). An active material discharge pump (12) and an active material discharge valve (14) are provided at the active material discharge port (13). A conveying mechanism passes through the liquid phase reaction system of the reaction zone. The reaction zone is also connected to a forced circulation pump (3), a gas-liquid shear mixing device, and an ultrasonic generator (15).

[0051] The gas-liquid shear mixing device includes a shear mixing device (5) with an ozone inlet (4), a solution inlet and a solution outlet, a circulation input pipeline connected to the solution inlet, and a circulation output pipeline (gas-liquid mixing pipeline 6) connected to the solution outlet. The input end (19) of the circulation input pipeline is located at or below the liquid surface of the liquid phase reaction system in the reaction zone. The nozzle (7) of the circulation output pipeline is located at the top, bottom or side of the reaction zone.

[0052] The conveying mechanism includes a transmission chain (9), chain guide wheels (16), a material hopper (8), a chain drive motor (17), and a drive wheel (18). Multiple chain guide wheels (16) are fixedly connected to the housing. The transmission chain (9) is looped around each chain guide wheel (16) in a closed loop. Material hoppers (8) are provided on each segment of the transmission chain (9). The transmission chain (9) is driven by the chain drive motor (17) and the drive wheel (18).

[0053] The device described in this invention deeply couples ultrasonic, ozone oxidation and shearing processes, enabling in-situ non-destructive stripping of positive and negative electrode active materials as well as deep removal of residual current collectors, organic matter and organic fluorine.

[0054] The equipment described in this invention mainly comprises a feeding device (1, 2), a discharging device (10, 11; 12, 13, 14), an ultrasonic device (15), a chain drive device (16, 17, 18), and a shearing device (5). During operation, the battery electrode sheets enter the loading hopper (8) through the discharging hopper (2) and then enter the reaction area via the chain drive (9). During the reaction, the ultrasonic device (15) and the shearing device (5) are simultaneously activated, and ozone is continuously introduced. During the reaction, ozone enters the high-speed rotating part of the shearing machine through the ozone inlet (4) and the slurry circulated from the input end, thereby achieving thorough mixing of the gas, liquid, and solid phases. Afterward, the uniformly mixed gas, liquid, and solid phases are sprayed into the reaction chamber through the mixture nozzle (7) to flush the battery electrode sheets and further accelerate the shearing of the active material. After the reaction is completed, the current collector and the active material are discharged through the current collector outlet (10) and the active material discharge port (13), respectively.

[0055] In this invention, the input end (19) is positioned as close as possible to the surface of the slurry in the early stages of slurry input. Preferably, the input end is inserted into the interior of the reaction solution system, and the distance from the lower surface of the liquid is controlled to be less than 5 cm, preferably less than 2 cm.

[0056] Beneficial effects

[0057] This invention innovatively employs an ultrasonic-ozone-assisted stripping process to achieve non-destructive in-situ stripping of battery active materials. The reaction process does not involve high-value, toxic reagents, resulting in excellent economic and technical performance. Unlike traditional pyrolysis processes, this reaction can be carried out at room temperature and does not produce harmful fluorine-containing gases. Furthermore, the chemical properties of copper and aluminum foil remain almost unchanged during the reaction, allowing for deep removal of copper and aluminum through simple acid or alkali leaching. This is highly beneficial for the extraction of valuable elements from battery materials or for the direct repair of battery materials.

[0058] In this invention, the electrode material obtained by stripping is treated with residual current collector and then subjected to shear ozone defluorination to obtain pure electrode active material. The introduction of shearing can greatly improve the defluorination effect, and further combined with the control of the circulation mode in the shear ozone treatment stage, the purpose of deep defluorination and degradation of organic matter can be achieved. Attached Figure Description

[0059] Figure 1 : Process flow diagram of the present invention.

[0060] Figure 2 The diagrams illustrate loop processing, with the left diagram showing a bottom-entry loop and the right diagram showing a top-entry loop.

[0061] Figure 3 : Schematic diagram of the ultrasonic-assisted ozone high-efficiency stripping device for battery active materials according to the present invention.

[0062] 1. Feeding motor; 2. Feeding hopper; 3. Forced circulation pump; 4. Ozone inlet; 5. Shearing and mixing device; 6. Gas-liquid mixing pipeline; 7. Gas-liquid mixture nozzle; 8. Loading hopper; 9. Drive chain; 10. Collector (copper foil or aluminum foil) outlet; 11. Collector unloading belt; 12. Active material unloading pump; 13. Active material unloading port; 14. Active material unloading valve; 15. Ultrasonic generator; 16. Chain guide wheel; 17. Chain drive motor; 18. Drive wheel; 19. Input end of the circulation input pipeline.

[0063] The detailed principle of the process of this invention is as follows:

[0064] (1) Decomposition and removal of organic matter

[0065] The organic matter in spent lithium-ion batteries mainly includes electrolytes and binders. The degradation reaction of PVDF is as follows:

[0066] [ CF2-CH2 ] n -(s)+O3(g)+H2O(l)→CO2(g)+HF(aq)

[0067] In addition, ozone can generate a certain amount of hydroxyl radicals (·OH) in aqueous solutions, which can further react with organic compounds such as PVDF. Taking PVDF as an example:

[0068] [ CF2-CH2 ] n (s)+·OH(aq)→CO2(g)+HF(aq)+H2O(l)

[0069] The main components of the electrolyte are ethylene carbonate (EC), ethyl methyl carbonate (EMC), propylene carbonate (PC), and diethyl carbonate (DEC). All of these substances are hydrocarbons, which will decompose into CO2 and H2O under the action of ozone.

[0070] (2) Deep removal of copper and aluminum

[0071] Cu(s)+H2SO4(aq)=CuSO4(aq)+H2(g)

[0072] Al(s)+NaOH(aq)+H2O(l)=NaAlO2(aq)+1.5H2(g)

[0073] (3) Lithium extraction and fluorine defluorination (using CaO as a defluorinating agent)

[0074] LiF(aq,s)+CaO(s)+H2O(l)=CaF2(s)↓+LiOH(aq)

[0075] HF(aq)+CaO(s)=CaF2(s)↓+H2O(l) Detailed Implementation

[0076] The recycling process described in this invention includes the following steps, for example:

[0077] (1) Discharge

[0078] Used lithium-ion batteries should be fully discharged by placing them in a saturated sodium chloride or sodium sulfate solution before use.

[0079] (2) Battery disassembly

[0080] The waste batteries described in step (1) are dismantled and separated manually or mechanically to obtain the negative and positive electrode sheets.

[0081] (3) Ultrasonic-assisted ozone stripping electrode active material

[0082] The battery electrodes described in step (2) are placed in an ultrasonic bath filled with water. The ultrasonic equipment is turned on and a certain flow rate of ozone gas is introduced to react for a certain period of time, and then the current collector (copper foil or aluminum foil), battery active material (positive active material or negative active material), ultrasonic post-solution A of the positive active material and ultrasonic post-solution B of the negative active material are obtained respectively.

[0083] (4) Deep removal of copper and aluminum

[0084] The positive electrode active material is further removed by alkaline leaching to remove residual aluminum foil debris; the negative electrode active material can be acid-leached under certain conditions to achieve deep removal of copper.

[0085] (5) Removal of fluoride and degradation of residual electrolyte under shear-assisted ozone conditions

[0086] The purified positive electrode active material and ultrasonic post-solution A, and the negative electrode active material and ultrasonic post-solution B, respectively, are placed in a shear-enhanced reaction device and ozone is continuously introduced for a certain period of time. During the shear reaction of the positive electrode active material, the material circulation method adopts top-in and bottom-out.

[0087] (6) Extraction of Li from solution system and open circuit of fluorine

[0088] The solution obtained in step (5) is recycled until the Li in the solution is reduced. + After F- accumulates to a certain level, a certain amount of defluorinating agent is added to the solution to remove the F- from the solution. - It transforms into a more stable fluoride precipitate, while simultaneously generating a lithium salt with greater solubility.

[0089] The ozone concentration mentioned in step (3) is 1-100 vol.%, and the introduction time is 15-90 min.

[0090] The volume ratio of the battery electrode to the aqueous phase in step (3) is 1:10 to 1:1.

[0091] The operating temperature in step (3) is 0 to 100°C, and more preferably 15 to 40°C.

[0092] The ultrasonic power mentioned in step (3) is 50 to 500W.

[0093] In step (5), the material circulation method of the shearing process is top-in and bottom-out, and the shearing rate is 1000-6000 r / min.

[0094] The shearing process described in step (5) has a reaction temperature of 20-60℃, a liquid-to-solid ratio of 3-5, and a reaction time of >30min.

[0095] I. Implementation Plan Using Existing Equipment

[0096] The following examples illustrate the essence of the present invention, but the scope of protection of the present invention is not limited thereto.

[0097] In the following examples, the unit for liquid-to-solid ratio refers to mL / g;

[0098] In the following examples, the current collector and binder components in the battery can all be conventional in the industry. For example, the positive electrode current collector can be Al foil, and the binder can be PVDF. The negative electrode current collector can be Cu foil, and the binder can be an oil-based or water-based binder, such as CMC. Specific examples are as follows:

[0099] Example 1 (Phosphorus iron cathode stripping)

[0100] Step 1: Disassemble the waste lithium iron phosphate battery to obtain the positive electrode and negative electrode. Cut the obtained positive electrode into small pieces with a side length of about 2cm and place them in an ultrasonic bath filled with water (a conventional ultrasonic bath can be used). Then, turn on the ultrasonic equipment (100W) and introduce ozone at a rate of 500mL / min. React at room temperature for 30 minutes to obtain aluminum foil, positive electrode active material, and ultrasonic post-reaction liquid.

[0101] Step 2: Place the ultrasonically stripped positive electrode active material in a liquid alkali reaction tank and react for 30 minutes at a temperature of 40℃ and a liquid-to-solid ratio of 4:1 to obtain a deeply aluminum-removed positive electrode active material.

[0102] Step 3: Mix the positive electrode active material after deep aluminum removal in Step 2 with the ultrasonic post-liquid obtained in Step 1 in a container to obtain a mixed solution, and use a top-entry circulation method (see schematic diagram). Figure 2 As shown in the right figure, the circulation inlet is located at a distance of less than or equal to 2 cm from the surface of the mixed solution. The mixed solution is sheared and mixed with ozone in a shear mixing device (e.g., FULAIFL40Z in this case), and circulated to the bottom of the mixed solution (at a distance of more than 10 cm from the surface) for 30 minutes. During the reaction, ozone is continuously introduced (500 mL / min). The temperature during the circulation reaction stage is 40℃, the liquid-to-solid ratio is 3:1, and the shearing speed is 3000 r / min. After the reaction, pure battery active material and leachate are obtained.

[0103] Chemical analysis and calculations revealed that the raw material contained 5.45% Li, 2.64% F, and 2.82% organic carbon, with the cathode material's phase being LiFePO4. After step one treatment, the stripping rate of the cathode active material was 99.01%, resulting in an Al content of 0.29%, F content of 2.54%, Li content of 4.25%, and organic carbon content of 2.14%. After step two treatment, the Al content decreased to 0.0085%, while the contents of other components remained essentially unchanged. After step three treatment, the F content decreased to 0.014%, the Li content decreased to 3.45%, and the organic carbon content decreased to 0.021%. After deep impurity removal, the main phase of the cathode active material was...

[0104] Example 2 (Ternary cathode stripping)

[0105] Step 1: Disassemble the waste ternary lithium-ion battery to obtain the positive electrode and negative electrode. Cut the obtained positive electrode into small pieces with a side length of about 2cm and place them in an ultrasonic tank filled with water. Then, turn on the ultrasonic equipment (100W) and introduce ozone at a rate of 500mL / min for 30 minutes to obtain aluminum foil, positive electrode active material, and ultrasonic post-reaction liquid.

[0106] Step 2: Place the ultrasonically stripped positive electrode active material in a liquid alkali reaction tank and react for 30 minutes at a temperature of 40℃ and a liquid-to-solid ratio of 4:1 to obtain the battery active material after deep aluminum removal.

[0107] Step 3: Mix the positive electrode active material after deep aluminum removal in Step 2 with the ultrasonic post-liquid obtained in Step 1 in a container to obtain a mixed solution, and use a top-entry circulation method (see schematic diagram). Figure 2 As shown in the right figure, the circulation inlet is located at a distance of less than or equal to 2 cm from the surface of the mixed solution. The mixed solution is sheared and mixed with ozone in a shear mixing device (e.g., FULAIFL40Z in this case), and circulated to the bottom of the mixed solution (at a distance of more than 10 cm from the surface) for 90 minutes. During the reaction, ozone is continuously introduced (500 mL / min). The temperature during the circulation reaction stage is 25℃, the liquid-to-solid ratio is 3:1, and the shearing speed is 3500 r / min. After the reaction, pure battery active material and leachate are obtained.

[0108] Chemical analysis and calculations revealed that the raw material contained 4.58% Li, 3.01% F, and 2.08% organic carbon. After step one treatment, the stripping rate of the positive electrode active material was 99.21%, and the resulting positive electrode material contained 0.19% Al, 2.57% F, 3.98% Li, and 1.75% organic carbon. After step two treatment, the Al content decreased to 0.0094%, while the contents of other components remained essentially unchanged. After step three treatment, the F content in the positive electrode active material decreased to 0.014%, the Li content decreased to 3.45%, and the organic carbon content decreased to 0.015%. Throughout the entire process, the leaching rates of Ni, Co, and Mn were all below 2.5%.

[0109] Example 3 (Negative Electrode Stripping)

[0110] Step 1: Disassemble the waste lithium iron phosphate battery to obtain positive and negative electrode sheets (the active component is graphite). Cut the negative electrode sheet into small pieces with a side length of about 2cm and place them in an ultrasonic bath filled with water. Then, turn on the ultrasonic equipment (80W) and react at room temperature for 20 minutes to obtain copper foil, negative electrode active material, and ultrasonic post-treatment solution.

[0111] Step 2: Place the ultrasonically stripped negative electrode active material in a dilute sulfuric acid reaction tank and react for 30 minutes at a temperature of 40℃ and a liquid-to-solid ratio of 4:1 to obtain the battery active material after deep copper removal.

[0112] Step 3: Mix the positive electrode active material after deep aluminum removal in Step 2 with the ultrasonic post-liquid obtained in Step 1 in a container to obtain a mixed solution, and use a top-entry circulation method (see schematic diagram). Figure 2 As shown in the right figure, the circulation inlet is located at a distance of less than or equal to 2 cm from the surface of the mixed solution. The circulating mixed solution is sheared and mixed with ozone in a shear mixing device (e.g., FULAIFL40Z in this case), and circulated to the bottom of the mixed solution (at a distance of more than 10 cm from the liquid surface) for 90 minutes. During the reaction, ozone is continuously introduced (500 mL / min). The temperature during the circulation reaction stage is 25℃, the liquid-to-solid ratio is 3:1, and the shearing speed is 3000 r / min. After the reaction, pure negative electrode active material and leachate are obtained.

[0113] Chemical analysis and calculations revealed that the organic carbon content in the raw material was 1.02%. After step one treatment, the stripping rate of the negative electrode active material was 99.25%, and the Cu content in the resulting positive electrode material was 0.19%, with an organic carbon content of 0.87%. After step two treatment, the Cu content decreased to 0.0024%. After step three treatment, the residual organic carbon rate in the negative electrode active material was 0.047%.

[0114] Example 4 (Fluorine precipitation and lithium extraction)

[0115] The leachates obtained in step three of Examples 1 and 2 were mixed evenly, and 1.3 times the theoretical amount of CaO for fluorine precipitation was added. After reacting at 60°C for 75 min, the mixture was filtered to obtain a Li-containing solution and a CaF2 precipitate, respectively. Then, CO2 was continuously bubbled into the Li-containing solution at room temperature for 30 min to obtain a LiHCO3 solution. The LiHCO3 solution was decarbonized at 90°C for 60 min, and then filtered, washed, and dried to obtain Li2CO3. The calculated precipitation rate of F was 96.24%, and the direct recovery rate and purity of lithium carbonate were 84.57% and 99.81%, respectively.

[0116] Example 5

[0117] Compared with Example 1, the only difference is that the ultrasonic power is 300W during the stripping process of the positive electrode active material in step one.

[0118] Chemical testing and calculations showed that the stripping rate of the positive electrode active material obtained in step one was 98.12%. The positive electrode sheet exhibited obvious perforation. The resulting positive electrode material contained 2.13% Al, 2.05% F, 5.38% Li, and the organic carbon content decreased to 1.95%. After step two treatment, the Al content decreased to 0.012%, while the contents of other components remained essentially unchanged. After step three treatment, the F content decreased to 0.015%, the Li content decreased to 3.55%, and the organic carbon content decreased to 0.019%. The main phases of the battery positive electrode active material after the above treatments are...

[0119] Example 6

[0120] Compared to Example 1, the only difference is that in step three, the loop method is changed to a bottom-up loop. Specifically, the input terminal of Example 1 is set as the output terminal, and the output terminal is set as the input terminal (see example for the loop method). Figure 2 (Left image).

[0121] Chemical analysis and calculations showed that the stripping rate of the positive electrode active material obtained in step one was 99.01%. The resulting positive electrode material contained 0.29% Al, 2.54% F, 4.25% Li, and the organic carbon content decreased to 2.68%. After step two treatment, the Al content decreased to 0.0078%, while the contents of other components remained essentially unchanged. After step three treatment, the F content decreased to 0.12%, the Li content decreased to 3.33%, and the organic carbon content decreased to 0.11%. The main phases of the battery positive electrode active material after the above treatments are...

[0122] Comparative Example 1 (Ultrasound alone)

[0123] Compared with Example 1, the only difference is that ozone was not introduced during the stripping process of the positive electrode active material in step one.

[0124] Chemical analysis and calculations showed that the stripping rate of the positive electrode active material obtained in step one was 30.12%, with Al content of 0.27%, F content of 2.55%, Li content of 5.01%, and organic carbon content of 2.64%. After step two treatment, the Al content decreased to 0.0072%, while the contents of other components remained essentially unchanged. After step three treatment, the F content decreased to 0.013%, the Li content decreased to 3.52%, and the organic carbon content decreased to 0.09%. The main phases of the battery positive electrode active material after the above treatments are...

[0125] Comparative Example 2 (Ozone alone)

[0126] Compared with Example 1, the only difference is that the ultrasonic equipment was not turned on during the peeling process of the positive electrode active material in step one.

[0127] Chemical analysis and calculations showed that the stripping rate of the positive electrode active material obtained in step one was 8.12%. The resulting positive electrode material contained 0.12% Al, 2.58% F, 5.38% Li, and the organic carbon content decreased to 2.44%. After step two treatment, the Al content decreased to 0.0066%, while the contents of other components remained essentially unchanged. After step three treatment, the F content decreased to 0.014%, the Li content decreased to 3.64%, and the organic carbon content decreased to 0.07%. The main phases of the battery positive electrode active material after the above treatments are...

[0128] Comparative Example 3

[0129] Compared with Example 1, the only difference is that the gas introduced during the stripping process of the positive electrode active material in step one is air with the same flow rate.

[0130] Chemical analysis and calculations showed that the stripping rate of the positive electrode active material obtained in step one was 5.12%. The resulting positive electrode material contained 0.13% Al, 2.38% F, 5.02% Li, and the organic carbon content decreased to 2.38%. After step two treatment, the Al content decreased to 0.0058%, while the contents of other components remained essentially unchanged. After step three treatment, the F content decreased to 0.014%, the Li content decreased to 3.64%, and the organic carbon content decreased to 0.07%. The main phases of the battery positive electrode active material after the above treatments are...

[0131] Comparative Example 4

[0132] Compared with Example 1, the only difference is that the gas introduced during the shear reaction in step three is air at the same flow rate.

[0133] Chemical analysis and calculations showed that after step one treatment, the stripping rate of the positive electrode active material was 99.21%, and the resulting positive electrode material contained 0.19% Al, 2.58% F, 4.33% Li, and 2.34% organic carbon. After step two treatment, the Al content decreased to 0.0078%, while the contents of other components remained essentially unchanged. After step three treatment, the F content decreased to 2.25%, the Li content decreased to 3.58%, and the organic carbon content decreased to 1.98%. After deep impurity removal, the main phases of the positive electrode active material were...

[0134]

[0135] Comparative Example 5

[0136] Compared with Example 1, the only difference is that in step three, a conventional circulating pump is used instead of the shear mixing device.

[0137] Chemical analysis and calculations showed that the stripping rate of the positive electrode active material obtained in step one was 99.01%. The resulting positive electrode material contained 0.29% Al, 2.54% F, 4.25% Li, and the organic carbon content decreased to 2.78%. After step two treatment, the Al content decreased to 0.0085%, while the contents of other components remained essentially unchanged. After step three treatment, the F content decreased to 0.54%, the Li content decreased to 3.45%, and the organic carbon content decreased to 0.19%. The main phases of the battery positive electrode active material after the above treatments are...

[0138] Second, adopting such Figure 3 The implementation scheme of the highly integrated device shown

[0139] like Figure 3 As shown: The waste battery electrode sheet stripping and recycling purification device includes a box body, which is provided with an inlet, an outlet (10) and a reaction zone. The inlet is provided with a feeding hopper (2) and a feeding motor (1), and the outlet is provided with a current collector unloading belt (11). The box body is provided with a conveying mechanism that passes through the inlet, the reaction zone and the outlet in sequence.

[0140] The reaction zone contains a liquid phase reaction system. The bottom of the reaction zone is provided with an active material discharge port (13). An active material discharge pump (12) and an active material discharge valve (14) are provided at the active material discharge port (13). A conveying mechanism passes through the liquid phase reaction system of the reaction zone. The reaction zone is also connected to a forced circulation pump (3), a gas-liquid shear mixing device, and an ultrasonic generator (15).

[0141] The gas-liquid shear mixing device includes a shear mixing device (5) with an ozone inlet (4), a solution inlet and a solution outlet, a circulation input pipeline connected to the solution inlet, and a circulation output pipeline (gas-liquid mixing pipeline 6) connected to the solution outlet. The input end (19) of the circulation input pipeline is located at or below the liquid surface of the liquid phase reaction system in the reaction zone. The nozzle (7) of the circulation output pipeline is located at the top, bottom or side of the reaction zone.

[0142] The conveying mechanism includes a transmission chain (9), chain guide wheels (16), a material hopper (8), a chain drive motor (17), and a drive wheel (18). Multiple chain guide wheels (16) are fixedly connected to the housing. The transmission chain (9) is looped around each chain guide wheel (16) in a closed loop. Material hoppers (8) are provided on each segment of the transmission chain (9). The transmission chain (9) is driven by the chain drive motor (17) and the drive wheel (18).

[0143] During operation, the battery electrode sheets enter the loading hopper (8) through the feeding hopper (2) and are then carried into the reaction zone by the chain drive (9). During the reaction, the ultrasonic device (15) and the shearing device (5) are simultaneously activated, and ozone is continuously introduced. During the reaction, ozone enters the high-speed rotating part of the shearing machine through the ozone inlet (4), thereby achieving thorough mixing of the gas, liquid, and solid phases. The uniformly mixed gas, liquid, and solid phases are then sprayed into the reaction chamber through the mixture nozzle (7) to flush the battery electrode sheets, further accelerating the shedding of the active material. After the reaction, the current collector and active material are discharged through the current collector outlet (10) and the active material discharge port (13), respectively.

[0144] In this invention, the input end (19) is positioned as close as possible to the surface of the slurry in the early stages of slurry input. Preferably, the input end is inserted into the interior of the reaction solution system, and the distance from the lower surface of the liquid is controlled to be less than 5 cm, preferably less than 2 cm.

[0145] Example 7

[0146] Compared with Example 1, the difference is that step one is... Figure 3 In the device, ultrasound is activated, and ozone is input through the ozone inlet for ultrasonic ozone treatment. Other conditions are the same as in Example 1. The peeling time can be controlled by adjusting the chain drive speed.

[0147] Furthermore, in step three: the positive electrode active material after deep aluminum removal in step two is mixed with the ultrasonic post-liquid obtained in step one, and then... Figure 2 The equipment on the right is used for processing, wherein the shearing and mixing equipment is model Chuangyue ONG-403-2. Other operations and parameters are the same as in Example 1.

[0148] After treatment, the stripping rate of the positive electrode active material was 99.08%. The resulting positive electrode material contained 0.23% Al, 0.54% F, 4.25% Li, and 1.05% organic carbon. After step two treatment, the Al content decreased to 0.0085%, while the contents of other components remained essentially unchanged. After step three treatment, the F content decreased to 0.013%, the Li content decreased to 3.58%, and the organic carbon content decreased to 0.019%. After deep impurity removal, the main phase of the positive electrode active material was...

Claims

1. A method for recycling and purifying electrode materials from waste battery electrode sheets, characterized in that, The crude electrode material is obtained by stripping. The crude electrode material is then subjected to deep de-current collector treatment to obtain a first-stage processed material. The first-stage processed material is then slurried and subjected to shear ozone-assisted defluorination treatment to obtain purified electrode material. The stripping method is as follows: the mixed system containing waste battery electrode sheets and aqueous solvent is stripped under ultrasonic and ozone assistance to separate the current collector and electrode active material in the electrode sheets; The device for implementing the recycling and purification method is a waste battery electrode stripping and recycling purification device, including a box body. The box body is provided with an inlet, an outlet (10) and a reaction zone. The inlet is provided with a feeding hopper (2) and a feeding motor (1). The outlet is provided with a current collector unloading belt (11). The box body is provided with a conveying mechanism that passes through the inlet, the reaction zone and the outlet in sequence. The reaction zone contains a liquid phase reaction system. The bottom of the reaction zone is provided with an active material discharge port (13). An active material discharge pump (12) and an active material discharge valve (14) are provided at the active material discharge port (13). A conveying mechanism passes through the liquid phase reaction system of the reaction zone. The reaction zone is also connected to a forced circulation pump (3), a gas-liquid shear mixing device, and an ultrasonic generator (15). The gas-liquid shear mixing device includes a shear mixing device (5) with an ozone inlet (4), a solution inlet and a solution outlet, a circulation input pipeline connected to the solution inlet, and a circulation output pipeline connected to the solution outlet. The circulation output pipeline is a gas-liquid mixing pipeline (6). The input end (19) of the circulation input pipeline is located at or below the liquid surface of the liquid phase reaction system in the reaction zone. The nozzle (7) of the circulation output pipeline is located at the top, bottom or side of the reaction zone. The conveying mechanism includes a transmission chain (9), chain guide wheels (16), a material hopper (8), a chain drive motor (17), and a drive wheel (18). Multiple chain guide wheels (16) are fixedly connected to the housing. The transmission chain (9) is looped around each chain guide wheel (16) in a closed loop. A material hopper (8) is provided on each segment of the transmission chain (9). The transmission chain (9) is driven by the chain drive motor (17) and the drive wheel (18).

2. The method for recycling and purifying waste battery electrode sheet materials as described in claim 1, characterized in that, The electrode sheets mentioned are electrode sheets obtained by disassembling and separating waste lithium-ion batteries.

3. The method for recycling and purifying waste battery electrode sheet materials as described in claim 2, characterized in that, The electrode plates include positive electrode plates and / or negative electrode plates.

4. The method for recycling and purifying waste battery electrode sheet materials as described in claim 1, characterized in that, The aqueous solvent is water, or a mixture of water and an organic solvent; the organic solvent is a solvent miscible with water and cannot be decomposed by ozone. The liquid-to-solid ratio of the electrode sheet to the aqueous solvent is 1~10 mL / g.

5. The method for recycling and purifying waste battery electrode sheet materials as described in claim 1, characterized in that, An ozone-containing atmosphere is introduced into a slurry containing waste battery electrode sheets and an aqueous solvent, and the material is stripped under ultrasonic assistance. The concentration of ozone in the ozone-containing atmosphere is above 1 vol.%. The power of ultrasound is 50~500 W.

6. The method for recycling and purifying waste battery electrode sheet materials as described in claim 1, characterized in that, The temperature during the peeling process is above 0 ℃, and the peeling time is above 5 min.

7. The method for recycling and purifying waste battery electrode sheet materials as described in claim 6, characterized in that, The temperature during the peeling process is 0~100 ℃, and the peeling time is 10~90 min.

8. The method for recycling and purifying waste battery electrode sheet materials as described in claim 7, characterized in that, The temperature during the peeling process is 15~40℃.

9. The method for recycling and purifying waste battery electrode sheet materials as described in claim 1, characterized in that, The deep desiccant treatment method is acid treatment or alkali treatment; When the electrode material contains a positive electrode material, its deep current collector removal treatment is an alkaline treatment; when the electrode material contains a negative electrode material, its deep current collector removal treatment is an acid treatment.

10. The method for recycling and purifying electrode materials from waste battery electrode sheets as described in claim 1, characterized in that, The solvent used in one part of the slurry processing is an aqueous solvent.

11. The method for recycling and purifying waste battery electrode sheet materials as described in claim 10, characterized in that, The solvent used in one stage of the slurry processing is the mother liquor from the solid-liquid separation after stripping.

12. The method for recycling and purifying waste battery electrode sheet materials as described in claim 10, characterized in that, The content of the primary treatment material in the slurry of the primary treatment material pulping stage is 3-5 g / mL.

13. The method for recycling and purifying waste battery electrode sheet materials as described in any one of claims 1 to 12, characterized in that, The aforementioned shear-assisted ozone treatment refers to a process in which a slurry containing a section of treatment material and ozone are mixed and reacted using a shear mixing device.

14. The method for recycling and purifying waste battery electrode sheet materials as described in claim 13, characterized in that, In the process of ozone-assisted defluorination, the slurry can be circulated into a shear mixing device and ozone shear mixing for recycling.

15. The method for recycling and purifying waste battery electrode sheet materials as described in claim 14, characterized in that, In the circulation process, the slurry circulation input end is located near the slurry surface; the slurry circulation output end is located above and / or below the slurry surface.

16. The method for recycling and purifying waste battery electrode sheet materials as described in claim 15, characterized in that, The input terminal for slurry circulation input is set at or below the slurry level.

17. The method for recycling and purifying waste battery electrode sheet materials as described in claim 16, characterized in that, The distance between the input end and the liquid surface is within 5cm.

18. The method for recycling and purifying waste battery electrode sheet materials as described in claim 17, characterized in that, The distance between the input end and the liquid surface is within 2cm.

19. The method for recycling and purifying electrode materials of waste battery electrode sheets as described in claim 13, characterized in that, The amount of ozone introduced during the ozone-assisted defluorination treatment stage is 1-10 times the theoretical amount.

20. The method for recycling and purifying electrode materials of waste battery electrode sheets as described in claim 19, characterized in that, The amount of ozone introduced during the ozone-assisted defluorination treatment stage is 2-5 times the theoretical amount.

21. The method for recycling and purifying electrode materials of waste battery electrode sheets as described in claim 19, characterized in that, The shear rate during the ozone-assisted defluorination treatment stage is 1000~6000 r / min; The reaction temperature for the ozone-assisted defluorination treatment stage is 10~60 ℃; The reaction time for the ozone-assisted defluorination treatment stage is >30 min.

22. The method for recycling and purifying electrode materials of waste battery electrode sheets as described in claim 19, characterized in that, After the ozone-assisted defluorination treatment is completed, solid-liquid separation is performed to obtain purified electrode materials and fluorine-containing and lithium-containing waste liquids respectively; after the above-mentioned fluorine-containing and lithium-containing waste liquids are defluorinated by a defluorinating agent, fluoride precipitates and lithium-containing solutions are obtained respectively.

23. A waste battery electrode stripping and recycling purification apparatus for implementing the recycling and purification method according to any one of claims 1 to 22, characterized in that, Includes a box body, which is provided with an inlet, an outlet (10) and a reaction zone. The inlet is provided with a feeding hopper (2) and a feeding motor (1), and the outlet is provided with a collector unloading belt (11). The box body is provided with a conveying mechanism that passes through the inlet, the reaction zone and the outlet in sequence. The reaction zone contains a liquid phase reaction system. The bottom of the reaction zone is provided with an active material discharge port (13). An active material discharge pump (12) and an active material discharge valve (14) are provided at the active material discharge port (13). A conveying mechanism passes through the liquid phase reaction system of the reaction zone. The reaction zone is also connected to a forced circulation pump (3), a gas-liquid shear mixing device, and an ultrasonic generator (15). The gas-liquid shear mixing device includes a shear mixing device (5) with an ozone inlet (4), a solution inlet and a solution outlet, a circulation input pipeline connected to the solution inlet, and a circulation output pipeline connected to the solution outlet. The circulation output pipeline is a gas-liquid mixing pipeline (6). The input end (19) of the circulation input pipeline is located at or below the liquid surface of the liquid phase reaction system in the reaction zone. The nozzle (7) of the circulation output pipeline is located at the top, bottom or side of the reaction zone. The conveying mechanism includes a transmission chain (9), chain guide wheels (16), a material hopper (8), a chain drive motor (17), and a drive wheel (18). Multiple chain guide wheels (16) are fixedly connected to the housing. The transmission chain (9) is looped around each chain guide wheel (16) in a closed loop. A material hopper (8) is provided on each segment of the transmission chain (9). The transmission chain (9) is driven by the chain drive motor (17) and the drive wheel (18).

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