Method for regenerating nickel-cobalt-manganese ternary positive electrode material by using waste lithium battery

Abstract

The invention discloses a method for regenerating a nickel-cobalt-manganese ternary positive electrode material by using a waste lithium battery. The method comprises the following steps: S1, pretreating the waste nickel-cobalt-manganese ternary lithium battery to obtain positive electrode material powder; s2, mixing acetic acid, molasses and the positive electrode material powder, performing leaching treatment to obtain a leaching solution, and performing ultrasonic treatment in the leaching treatment process; s3, the molar ratio of metal ions in the leachate is detected, then a nickel source, a cobalt source and a manganese source are supplemented into the leachate so that the molar ratio of nickel ions, cobalt ions and manganese ions can meet the requirement, and nickel-cobalt-manganese mixed liquid is obtained after dissolution; s4, performing spray granulation on the nickel-cobalt-manganese mixed solution to obtain a ternary precursor; and S5, roasting the ternary precursor at high temperature to obtain the regenerated nickel-cobalt-manganese ternary positive electrode material. The ultrasonic treatment comprises the steps of firstly adopting ultrasonic waves with the frequency range of 50-80KHz and then adopting ultrasonic waves with the frequency range of 20-35KHz. According to the method, the leaching rate of metal ions can be improved, and the prepared regenerated nickel-cobalt-manganese ternary positive electrode material has higher crystallinity and purity.

Description

Technical Field

[0001] The invention belongs to the technical field of waste lithium battery recycling, and in particular relates to a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries. Background Art

[0002] The ternary nickel-cobalt-manganese cathode material is a key component of lithium-ion batteries and is highly favored for its high energy density, excellent stability and safety. When these lithium-ion batteries reach the end of their service life, if they are not handled properly, they will not only cause environmental pollution, but also lead to a waste of precious resources. It is worth noting that retired nickel-cobalt-manganese ternary lithium batteries are rich in valuable metals such as lithium, cobalt, and manganese. Compared with the original ore, these metals are in higher concentrations and have fewer impurities in waste batteries, so they have great potential for recycling and reuse.

[0003] At present, the industry mainly uses pyrometallurgy, hydrometallurgy or a combination of the two to recover valuable metal elements from waste lithium batteries. The pyrometallurgical process involves placing waste lithium-ion batteries in a high-temperature smelting furnace over 1000°C. During this process, the organic components in the battery are burned and removed, low-melting metals form alloys, and low-boiling metals and their compounds are recovered by condensation. Other impurities are converted into slag or gas and discharged; although this method is applicable to different types of waste lithium-ion batteries and has the advantages of simple process and high efficiency, it also has some defects, such as some manganese and lithium will be left in the slag to cause losses, and may cause air pollution. On the other hand, hydrometallurgy is to separate and enrich the valuable metal components in waste lithium-ion batteries by using chemical solutions (such as acid and alkali solutions), and finally obtain products in the form of metal salts or precipitates. Hydrometallurgy has low investment costs, good production flexibility, and can achieve high metal recovery rates; however, this method relies on chemicals such as strong acids, strong bases and extractants, which may cause equipment corrosion problems, while increasing environmental pollution risks and production safety challenges.

[0004] Therefore, there is an urgent need for a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries to solve the shortcomings of the existing technical problems. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries, which method can minimize the impact on the environment and significantly improve the leaching rate of metal ions. The regenerated nickel-cobalt-manganese ternary positive electrode material prepared by this method has higher crystallinity and purity.

[0006] To achieve the above objectives, the present invention provides a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries, the steps comprising:

[0007] S1. Pre-treating waste nickel-cobalt-manganese ternary lithium batteries to obtain positive electrode material powder;

[0008] S2, mixing acetic acid, molasses and cathode material powder and performing leaching treatment to obtain a leachate, and performing ultrasonic treatment during the leaching process;

[0009] S3, detecting the molar ratio of each metal ion in the leachate, and then adding a nickel source, a cobalt source, and a manganese source to the leachate so that the molar ratio of nickel ions, cobalt ions, and manganese ions meets the requirements of the ternary product with the required nickel content, and obtaining a nickel-cobalt-manganese mixed solution after dissolution;

[0010] S4, spraying and granulating the nickel-cobalt-manganese mixed solution to obtain a ternary precursor;

[0011] S5, calcining the ternary precursor at high temperature to obtain a regenerated nickel-cobalt-manganese ternary positive electrode material;

[0012] The ultrasonic treatment includes firstly performing high-frequency ultrasonic treatment with ultrasonic waves in a frequency range of 50 to 80 KHz, and then performing low-frequency ultrasonic treatment with ultrasonic waves in a frequency range of 20 to 35 KHz.

[0013] Compared with the prior art, the method provided by the present invention for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries has the following beneficial effects:

[0014] 1. The present invention adopts a combination of acetic acid and molasses. Under the acidic environment provided by acetic acid, molasses is hydrolyzed to generate reducing sugars and a certain amount of organic acid, wherein the reducing sugars can effectively reduce high-valent nickel, cobalt, and manganese compounds to low-valent metal ions; at the same time, the organic acid further promotes the reduction process of the high-valent metal by virtue of its dual characteristics of reducing and acidity, so the leaching rate of the metal ions is significantly improved through the synergistic effect between the reducing sugars and the organic acid.

[0015] 2. In the leaching process, the present invention first uses high-frequency ultrasound to destroy small aggregates, so that the originally tightly packed particles are dispersed, thereby significantly improving the transfer efficiency of metal ions from solid to liquid; then switches to low-frequency ultrasound, which has a longer wavelength and can better penetrate thicker solid structures, ensuring the thoroughness and uniformity of the leaching process; in addition, the entire process does not require additional temperature control devices to control the temperature to remain constant, and only needs to input different frequencies in stages, which obviously avoids energy waste. Therefore, the combination of high and low frequency ultrasound greatly shortens the time required for leaching, improves the metal ion leaching rate and reduces energy consumption.

[0016] 3. The present invention combines spray drying and high-temperature calcination to achieve regeneration. Spray drying can quickly convert the nickel-cobalt-manganese mixed solution into uniform microparticles, maintain the high dispersion of active substances, and lay a good foundation for crystal growth; while high-temperature calcination provides a thermal activation environment, promotes the orderly arrangement of atoms, forms a stable crystal structure, and removes residual solvents and volatile impurities to improve purity. Therefore, the present invention combines spray drying and high-temperature calcination to ensure that the final nickel-cobalt-manganese ternary positive electrode material product has higher crystallinity and purity.

[0017] 4. The present invention uses acetic acid as a leaching agent and molasses as a reducing agent, both of which are environmentally friendly reagents, which significantly reduce the emission of harmful substances in the process, including waste gas, waste water and solid waste. Therefore, the method provided by the present invention can minimize the impact on the environment.

[0018] Furthermore, the pretreatment in step S1 of the present invention includes firstly decomposing and splitting the waste nickel-cobalt-manganese ternary lithium batteries to obtain positive electrode sheets; and then crushing and screening the positive electrode sheets.

[0019] Further, in step S2 of the present invention, the concentration of acetic acid is 1.5-3M, and the mass volume ratio of molasses is 70-80%. Specifically, the concentration of acetic acid can be but not limited to 1.5mol / L, 1.8mol / L, 2.2mol / L, 2.6mol / L, 3mol / L; specifically, the mass volume ratio of molasses refers to the density characteristics of molasses, that is, the density of molasses can be but not limited to 0.70g / mL, 0.75g / mL, 0.78g / mL, 0.80g / mL. Molasses is a by-product of the sugar industry. It is a viscous, dark brown, semi-fluid object that mainly contains sucrose, and also contains ingredients such as pantothenic acid and biotin.

[0020] Further, the leaching treatment conditions in step S2 of the present invention are: the leaching solid-liquid ratio is 90-110 g / L, the leaching temperature is 50-95° C., and the leaching time is 50-70 min. In particular, the mass ratio of acetic acid to molasses needs to be flexibly adjusted according to the specific content of nickel, cobalt and manganese (NCM) in the positive electrode material powder to achieve the best leaching effect. Therefore, the mass ratio of acetic acid to molasses is not specifically limited, and the optimal ratio is determined by those skilled in the art according to actual needs. In addition, during the leaching process, the leaching temperature can be controlled between 50 and 95° C. by combining high and low frequency ultrasound, that is, the entire leaching process does not require additional temperature control devices to control the temperature.

[0021] Furthermore, in step S3 of the present invention, ultrasonic waves are used for dissolution.

[0022] Furthermore, in step S3 of the present invention, the molar ratio of each metal ion in the leachate is determined by using ICP-OES (inductively coupled plasma optical emission spectroscopy) or ICP-MS (inductively coupled plasma mass spectrometry) technology.

[0023] Furthermore, the nickel source of the present invention is nickel acetate tetrahydrate; the cobalt source is cobalt acetate tetrahydrate; and the manganese source is manganese acetate tetrahydrate.

[0024] Furthermore, the molar ratio of nickel ions, cobalt ions and manganese ions in the ternary product with the required nickel content of the present invention is 1-8:1-3:1-3.

[0025] Furthermore, the molar ratio of nickel ions, cobalt ions and manganese ions in the ternary product with the required nickel content of the present invention is 1:1:1, 5:2:3 or 8:1:1.

[0026] Furthermore, step S4 of the present invention includes placing the nickel-cobalt-manganese mixed solution into a spray dryer and performing spray granulation using nitrogen as a protective gas to obtain a ternary precursor.

[0027] Furthermore, in step S5 of the present invention, the high temperature calcination includes heating to 700-900° C. at a heating rate of 4-6° C. / min and keeping the temperature for 5-7 hours. DETAILED DESCRIPTION

[0028] In order to better illustrate the purpose, technical scheme and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be noted that the following implementation method is a further explanation of the present invention and should not be used as a limitation of the present invention.

[0029] The raw materials used in the embodiments and comparative examples are all commercially available, such as molasses purchased from Jinan Xinyuchengtai Chemical Technology Co., Ltd.

[0030] Example 1

[0031] This embodiment provides a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries, the steps comprising:

[0032] S1, the battery capacity decay is serious waste NCM523 (LiNi 0.5 C 0.2 Mn 0.3 O2) The lithium battery is discharged, and the discharge is completed when the battery voltage is lower than 0.5V, and then the battery is disassembled to obtain the positive electrode sheet, and then the positive electrode sheet is crushed to obtain a powder with a particle size of 70 to 90um, and then a #200 mesh screen is coupled with a vibration stirrer for screening to obtain a positive electrode material powder;

[0033] S2, acetic acid, molasses and positive electrode material powder are mixed and then leached to obtain a leachate, and ultrasonic treatment is performed simultaneously during the leaching process; wherein the concentration of acetic acid is 2 mol / L, and the mass volume ratio of molasses is 75%; the leaching treatment conditions are: the leaching solid-liquid ratio is 100 g / L, the leaching temperature is 50-95° C., and the leaching time is 60 min; the ultrasonic treatment includes first using an ultrasonic wave with a frequency range of 80 KHz for high-frequency ultrasonic treatment for 30 min, and then using an ultrasonic wave with a frequency range of 30 KHz for low-frequency ultrasonic treatment for 30 min;

[0034] S3, performing elemental analysis on the leachate by ICP-OES to obtain the molar ratio of nickel, cobalt and manganese, and then adding nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate to the leachate to make the molar ratio of nickel ion, cobalt ion and manganese ion satisfy 5:2:3, and dissolving by ultrasonic to obtain a nickel-cobalt-manganese mixed solution;

[0035] S4, placing the nickel-cobalt-manganese mixed solution into a spray dryer and performing spray granulation using nitrogen as a protective gas to obtain a ternary precursor; wherein the feed rate is controlled to be 25 mL / min, the inlet temperature is 210° C., and the fan frequency is 60 Hz;

[0036] S5. Heat the ternary precursor to 800°C at a heating rate of 5°C / min and keep it at that temperature for 7 hours to obtain a regenerated nickel-cobalt-manganese ternary positive electrode material.

[0037] Example 2

[0038] This embodiment provides a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries, the steps comprising:

[0039] S1, the battery capacity decay is serious waste NCM523 (LiNi 0.5 C 0.2 Mn 0.3 O2) The lithium battery is discharged, and the discharge is completed when the battery voltage is lower than 0.5V, and then the battery is disassembled to obtain the positive electrode sheet, and then the positive electrode sheet is crushed to obtain a powder with a particle size of 70 to 90um, and then a #200 mesh screen is coupled with a vibration stirrer for screening to obtain a positive electrode material powder;

[0040] S2, acetic acid, molasses and cathode material powder are mixed and then leached to obtain a leachate, and ultrasonic treatment is performed during the leaching process; wherein the concentration of acetic acid is 3 mol / L, and the mass volume ratio of molasses is 80%; the leaching conditions are: the leaching solid-liquid ratio is 110 g / L, the leaching temperature is 50-95° C., and the leaching time is 70 min; the ultrasonic treatment includes first using an ultrasonic wave with a frequency range of 70 KHz for high-frequency ultrasonic treatment for 40 min, and then using an ultrasonic wave with a frequency range of 25 KHz for low-frequency ultrasonic treatment for 30 min;

[0041] S3, performing elemental analysis on the leachate by ICP-OES to obtain the molar ratio of nickel, cobalt and manganese, and then adding nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate to the leachate to make the molar ratio of nickel ion, cobalt ion and manganese ion satisfy 5:2:3, and dissolving by ultrasonic to obtain a nickel-cobalt-manganese mixed solution;

[0042] S4, placing the nickel-cobalt-manganese mixed solution into a spray dryer and performing spray granulation using nitrogen as a protective gas to obtain a ternary precursor; wherein the feed rate is controlled to be 25 mL / min, the inlet temperature is 210° C., and the fan frequency is 60 Hz;

[0043] S5. Heat the ternary precursor to 860°C at a heating rate of 6°C / min and keep the temperature for 6.5 hours to obtain a regenerated nickel-cobalt-manganese ternary positive electrode material.

[0044] Example 3

[0045] This embodiment provides a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries, the steps comprising:

[0046] S1, the battery capacity decay is serious waste NCM523 (LiNi 0.5 C 0.2 Mn 0.3 O2) The lithium battery is discharged, and the discharge is completed when the battery voltage is lower than 0.5V, and then the battery is disassembled to obtain the positive electrode sheet, and then the positive electrode sheet is crushed to obtain a powder with a particle size of 70 to 90um, and then a #200 mesh screen is coupled with a vibration stirrer for screening to obtain a positive electrode material powder;

[0047] S2, acetic acid, molasses and positive electrode material powder are mixed and then leached to obtain a leachate, and ultrasonic treatment is performed during the leaching process; wherein the concentration of acetic acid is 1.5 mol / L, and the mass volume ratio of molasses is 70%; the leaching treatment conditions are: the leaching solid-liquid ratio is 90 g / L, the leaching temperature is 50-95° C., and the leaching time is 55 min; the ultrasonic treatment includes first using an ultrasonic wave with a frequency range of 60 KHz for high-frequency ultrasonic treatment for 20 min, and then using an ultrasonic wave with a frequency range of 22 KHz for low-frequency ultrasonic treatment for 35 min;

[0048] S3, performing elemental analysis on the leachate by ICP-OES to obtain the molar ratio of nickel, cobalt and manganese, and then adding nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate to the leachate to make the molar ratio of nickel ion, cobalt ion and manganese ion satisfy 5:2:3, and dissolving by ultrasonic to obtain a nickel-cobalt-manganese mixed solution;

[0049] S4, placing the nickel-cobalt-manganese mixed solution into a spray dryer and performing spray granulation using nitrogen as a protective gas to obtain a ternary precursor; wherein the feed rate is controlled to be 25 mL / min, the inlet temperature is 210° C., and the fan frequency is 60 Hz;

[0050] S5. Heat the ternary precursor to 780°C at a heating rate of 4°C / min and keep the temperature for 6 hours to obtain a regenerated nickel-cobalt-manganese ternary positive electrode material.

[0051] Comparative Example 1

[0052] This comparative example provides a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries, the steps comprising:

[0053] S1, the battery capacity decay is serious waste NCM523 (LiNi 0.5 C 0.2 Mn 0.3 O2) The lithium battery is discharged, and the discharge is completed when the battery voltage is lower than 0.5V, and then the battery is disassembled to obtain the positive electrode sheet, and then the positive electrode sheet is crushed to obtain a powder with a particle size of 70 to 90um, and then a #200 mesh screen is coupled with a vibration stirrer for screening to obtain a positive electrode material powder;

[0054] S2, acetic acid, molasses and positive electrode material powder are mixed and then leached to obtain a leachate, and a stirring paddle is used during the leaching process and stirred at a speed of 500 rpm for 60 minutes; wherein the concentration of acetic acid is 2 mol / L, and the mass volume ratio of molasses is 75%; the leaching treatment conditions are: the leaching solid-liquid ratio is 100 g / L, the leaching temperature is controlled to be constant at 90° C. by a temperature control device, and the leaching time is 60 minutes;

[0055] S3, performing elemental analysis on the leachate by ICP-OES to obtain the molar ratio of nickel, cobalt and manganese, and then adding nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate to the leachate to make the molar ratio of nickel ion, cobalt ion and manganese ion satisfy 5:2:3, and dissolving by ultrasonic to obtain a nickel-cobalt-manganese mixed solution;

[0056] S4, placing the nickel-cobalt-manganese mixed solution into a spray dryer and performing spray granulation using nitrogen as a protective gas to obtain a ternary precursor; wherein the feed rate is controlled to be 25 mL / min, the inlet temperature is 210° C., and the fan frequency is 60 Hz;

[0057] S5. Heat the ternary precursor to 800°C at a heating rate of 5°C / min and keep it at that temperature for 7 hours to obtain a regenerated nickel-cobalt-manganese ternary positive electrode material.

[0058] Comparative Example 2

[0059] This comparative example provides a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries, the steps comprising:

[0060] S1, the battery capacity decay is serious waste NCM523 (LiNi 0.5 C 0.2 Mn 0.3 O2) The lithium battery is discharged, and the discharge is completed when the battery voltage is lower than 0.5V, and then the battery is disassembled to obtain the positive electrode sheet, and then the positive electrode sheet is crushed to obtain a powder with a particle size of 70 to 90um, and then a #200 mesh screen is coupled with a vibration stirrer for screening to obtain a positive electrode material powder;

[0061] S2, acetic acid, molasses and positive electrode material powder are mixed and then leached to obtain a leachate, and ultrasonic treatment is performed during the leaching process; wherein the concentration of acetic acid is 2 mol / L, and the mass volume ratio of molasses is 75%; the leaching treatment conditions are: the leaching solid-liquid ratio is 100 g / L, the leaching temperature is controlled to be constant at 90° C. by a temperature control device, and the leaching time is 60 min; the ultrasonic treatment includes low-frequency ultrasonic treatment for 60 min using ultrasonic waves with a frequency range of 30 KHz;

[0062] S3, performing elemental analysis on the leachate by ICP-OES to obtain the molar ratio of nickel, cobalt and manganese, and then adding nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate to the leachate to make the molar ratio of nickel ion, cobalt ion and manganese ion satisfy 5:2:3, and dissolving by ultrasonic to obtain a nickel-cobalt-manganese mixed solution;

[0063] S4, placing the nickel-cobalt-manganese mixed solution into a spray dryer and performing spray granulation using nitrogen as a protective gas to obtain a ternary precursor; wherein the feed rate is controlled to be 25 mL / min, the inlet temperature is 210° C., and the fan frequency is 60 Hz;

[0064] S5. Heat the ternary precursor to 800°C at a heating rate of 5°C / min and keep it at that temperature for 7 hours to obtain a regenerated nickel-cobalt-manganese ternary positive electrode material.

[0065] Comparative Example 3

[0066] This comparative example provides a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries, the steps comprising:

[0067] S1, the battery capacity decay is serious waste NCM523 (LiNi 0.5 C 0.2 Mn 0.3 O2) The lithium battery is discharged, and the discharge is completed when the battery voltage is lower than 0.5V, and then the battery is disassembled to obtain the positive electrode sheet, and then the positive electrode sheet is crushed to obtain a powder with a particle size of 70 to 90um, and then a #200 mesh screen is coupled with a vibration stirrer for screening to obtain a positive electrode material powder;

[0068] S2, leaching the mixture of acetic acid, molasses and cathode material powder to obtain a leachate, and simultaneously performing ultrasonic treatment during the leaching process; wherein the concentration of acetic acid is 2 mol / L, and the mass volume ratio of molasses is 75%; the leaching treatment conditions are: the leaching solid-liquid ratio is 100 g / L, the leaching temperature is 50-185° C., and the leaching time is 60 min; the ultrasonic treatment includes high-frequency ultrasonic treatment for 60 min using ultrasonic waves with a frequency range of 80 KHz;

[0069] S3, performing elemental analysis on the leachate by ICP-OES to obtain the molar ratio of nickel, cobalt and manganese, and then adding nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate to the leachate to make the molar ratio of nickel ion, cobalt ion and manganese ion satisfy 5:2:3, and dissolving by ultrasonic to obtain a nickel-cobalt-manganese mixed solution;

[0070] S4, placing the nickel-cobalt-manganese mixed solution into a spray dryer and performing spray granulation using nitrogen as a protective gas to obtain a ternary precursor; wherein the feed rate is controlled to be 25 mL / min, the inlet temperature is 210° C., and the fan frequency is 60 Hz;

[0071] S5. Heat the ternary precursor to 800°C at a heating rate of 5°C / min and keep it at that temperature for 7 hours to obtain a regenerated nickel-cobalt-manganese ternary positive electrode material.

[0072] Comparative Example 4

[0073] This comparative example provides a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries, the steps comprising:

[0074] S1, the battery capacity decay is serious waste NCM523 (LiNi 0.5 C 0.2 Mn 0.3 O2) The lithium battery is discharged, and the discharge is completed when the battery voltage is lower than 0.5V, and then the battery is disassembled to obtain the positive electrode sheet, and then the positive electrode sheet is crushed to obtain a powder with a particle size of 70 to 90um, and then a #200 mesh screen is coupled with a vibration stirrer for screening to obtain a positive electrode material powder;

[0075] S2, acetic acid, molasses and positive electrode material powder are mixed and then leached to obtain a leachate, and ultrasonic treatment is performed during the leaching process; wherein the concentration of acetic acid is 2 mol / L, and the mass volume ratio of molasses is 75%; the leaching treatment conditions are: the leaching solid-liquid ratio is 100 g / L, the leaching temperature is controlled to be constant at 90° C. by a temperature control device, and the leaching time is 60 min; the ultrasonic treatment includes high-frequency ultrasonic treatment for 60 min using ultrasonic waves with a frequency range of 80 KHz;

[0076] S3, performing elemental analysis on the leachate by ICP-OES to obtain the molar ratio of nickel, cobalt and manganese, and then adding nickel acetate tetrahydrate, cobalt acetate tetrahydrate and manganese acetate tetrahydrate to the leachate to make the molar ratio of nickel ion, cobalt ion and manganese ion satisfy 5:2:3, and dissolving by ultrasonic to obtain a nickel-cobalt-manganese mixed solution;

[0077] S4, placing the nickel-cobalt-manganese mixed solution into a spray dryer and performing spray granulation using nitrogen as a protective gas to obtain a ternary precursor; wherein the feed rate is controlled to be 25 mL / min, the inlet temperature is 210° C., and the fan frequency is 60 Hz;

[0078] S5. Heat the ternary precursor to 800°C at a heating rate of 5°C / min and keep it at that temperature for 7 hours to obtain a regenerated nickel-cobalt-manganese ternary positive electrode material.

[0079] Comparative Example 5

[0080] This comparative example provides a method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries, which is basically the same as Example 1, and the only difference between the two is that molasses is replaced with glucose.

[0081] ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry) was used to determine the concentrations of nickel, cobalt, manganese and lithium in the leaching solution of step S2 in Examples 1 to 3 and Comparative Examples 1 to 5, and the masses of these metal elements were calculated accordingly. 0.5 C 0.2Mn 0.3 The mass of nickel, cobalt, manganese and lithium originally in the lithium battery (O2) and the mass of the corresponding metal elements measured from the leaching solution can determine the leaching efficiency of each element. The leaching rate results of nickel, cobalt, manganese and lithium are shown in Table 1.

[0082] The cycle performance of the regenerated nickel-cobalt-manganese ternary positive electrode materials obtained in Examples 1 to 3 was tested by a half-cell test method, and the results are shown in Table 2. The half-cell test method is as follows: the regenerated nickel-cobalt-manganese ternary positive electrode materials obtained in Examples 1 to 3 were crushed and sieved, and then ground with conductive carbon black in a mortar at a mass ratio of 8:1 to ensure that the two were fully and evenly mixed; then an appropriate amount of polyvinylidene fluoride (PVDF) was added to maintain the mass ratio of the ternary positive electrode material, conductive carbon black and PVDF at 8:1:1. Then N-methylpyrrolidone (NMP) was added to the mixed material as a solvent, and after sufficient stirring, the slurry was evenly coated on the current collector aluminum foil, placed in an oven to dry, and pressed and cut to obtain a circular positive electrode sheet with a punching diameter of 14 cm. Then it was transferred to a German Mikaelona glove box filled with argon gas and assembled into a 2430 button cell, with a three-component mixed solvent of 1 mol / L LiPF6 in the ratio of EC:DMC:EMC=1:1:1 (volume ratio) as the electrolyte, a metal lithium sheet as the counter electrode, and a 16μm thick polypropylene microporous membrane as the isolation membrane to form a half-cell. The battery tester was used to test the charge and discharge performance, and the charge and discharge were carried out at 2.75~4.3V and 1C rate. After 50 cycles, the discharge capacity was tested; the capacity retention rate = discharge capacity after 50 cycles / first discharge capacity × 100%.

[0083] Table 1

[0084] Group Nickel leaching rate / % Cobalt leaching rate / % Manganese leaching rate / % Lithium leaching rate / % Example 1 91 94 93 97 Example 2 93 96 95 98 Example 3 90 92 91 95 Comparative Example 1 83 78 81 79 Comparative Example 2 86 82 84 83 Comparative Example 3 88 90 89 86 Comparative Example 4 90 95 92 98 Comparative Example 5 83 86 85 89

[0085] Table 2

[0086]

[0087] By comparing Examples 1 to 3 with Comparative Example 1, it can be seen that the methods using Examples 1 to 3 have a relatively higher metal leaching rate. This is because when only conventional mechanical stirring is used, the leaching rate is low due to the lack of an effective energy input method to break the agglomeration between particles.

[0088] By comparing Examples 1 to 3 with Comparative Example 2, it can be seen that the methods using Examples 1 to 3 have a relatively higher metal leaching rate. This is because in the leaching process, high-frequency ultrasound is first used to destroy fine agglomerates, and then switched to low-frequency ultrasound to ensure the thoroughness and uniformity of the leaching process. This combination of high and low frequencies significantly improves the leaching efficiency of metal ions.

[0089] By comparing Examples 1 to 3 with Comparative Example 3, it can be seen that the methods of Examples 1 to 3 have a relatively higher metal leaching rate. This is because if only high-frequency ultrasonic treatment is used throughout the process, although the leaching rate is improved in a short period of time, continuous high-frequency ultrasound will cause the system temperature to increase significantly. This temperature increase will cause the acidic substances to volatilize due to heat, thereby reducing the leaching rate.

[0090] By comparing Examples 1 to 3 and Comparative Example 4, it can be seen that the two show similar results in metal leaching rate. This is because Comparative Example 4 uses full-process high-frequency ultrasonic treatment and combines a temperature control device to maintain a constant leaching temperature, thereby avoiding the volatilization of acidic substances due to excessively high temperature, thereby preventing the metal leaching rate from decreasing. However, although the method of Comparative Example 4 can effectively improve the leaching rate, its energy consumption increases significantly; this is because the total energy demand of Comparative Example 4 includes the energy consumption required for full-process high-frequency ultrasound and the additional temperature control energy consumption; in contrast, Examples 1 to 3 only use a combination of high and low frequencies to reduce overall energy consumption while maintaining a high efficiency leaching rate, thereby achieving a more economical operation method.

[0091] By comparing Examples 1 to 4 with Comparative Example 5, it can be seen that the methods using Examples 1 to 3 have a relatively higher metal leaching rate. This is because the present application uses a combination of acetic acid and molasses, which not only provides a suitable acidic environment, but also generates reducing sugars and a variety of organic acids through molasses hydrolysis. These components jointly promote the reduction of high-valent metals, thereby significantly improving the leaching rate of metal ions; and although the glucose used in Comparative Example 5 also has a certain reducing property, it lacks the various organic acids and their acidic properties produced after molasses hydrolysis, and therefore cannot promote the leaching of metal ions through a dual mechanism like molasses.

[0092] It can be seen from Table 2 that after the regenerated nickel-cobalt-manganese ternary positive electrode materials of Examples 1 to 3 are assembled into half-cells, the capacity retention rates are all above 93%, which indicates that the regenerated nickel-cobalt-manganese ternary positive electrode materials obtained by the method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries provided by the present invention have good electrochemical properties, which also indirectly proves that the regenerated nickel-cobalt-manganese ternary positive electrode materials have high crystallinity and purity.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for regenerating nickel-cobalt-manganese ternary positive electrode materials using waste lithium batteries, characterized in that the steps include: S1. Pre-treating waste nickel-cobalt-manganese ternary lithium batteries to obtain positive electrode material powder; S2, mixing acetic acid, molasses and the positive electrode material powder and performing leaching treatment to obtain a leachate, and performing ultrasonic treatment during the leaching process; S3, detecting the molar ratio of each metal ion in the leachate, and then adding a nickel source, a cobalt source, and a manganese source to the leachate so that the molar ratio of nickel ions, cobalt ions, and manganese ions meets the requirements of the ternary product with the required nickel content, and obtaining a nickel-cobalt-manganese mixed solution after dissolution; S4, spraying and granulating the nickel-cobalt-manganese mixed solution to obtain a ternary precursor; S5, calcining the ternary precursor at high temperature to obtain a regenerated nickel-cobalt-manganese ternary positive electrode material; The ultrasonic treatment includes firstly performing high-frequency ultrasonic treatment with ultrasonic waves in a frequency range of 50 to 80 KHz, and then performing low-frequency ultrasonic treatment with ultrasonic waves in a frequency range of 20 to 35 KHz.

2. The method for regenerating nickel-cobalt-manganese ternary positive electrode material using waste lithium batteries as claimed in claim 1, characterized in that: The pretreatment in step S1 includes firstly decomposing and splitting the waste nickel-cobalt-manganese ternary lithium batteries to obtain positive electrode sheets; and then crushing and screening the positive electrode sheets.

3. The method for regenerating nickel-cobalt-manganese ternary positive electrode material using waste lithium batteries as claimed in claim 1, characterized in that: The concentration of the acetic acid in step S2 is 1.5-3M, and the mass volume ratio of the molasses is 70-80%.

4. The method for regenerating nickel-cobalt-manganese ternary positive electrode material using waste lithium batteries as claimed in claim 1, characterized in that: The leaching treatment conditions in step S2 are: leaching solid-liquid ratio of 90-110 g / L, leaching temperature of 50-95° C., and leaching time of 50-70 min.

5. The method for regenerating nickel-cobalt-manganese ternary positive electrode material using waste lithium batteries as claimed in claim 1, characterized in that: In step S3, ultrasonic wave is used for dissolution.

6. The method for regenerating nickel-cobalt-manganese ternary positive electrode material using waste lithium batteries as claimed in claim 1, characterized in that: The nickel source is nickel acetate tetrahydrate; the cobalt source is cobalt acetate tetrahydrate; and the manganese source is manganese acetate tetrahydrate.

7. The method for regenerating nickel-cobalt-manganese ternary positive electrode material using waste lithium batteries as claimed in claim 1, characterized in that: The molar ratio of nickel ion, cobalt ion and manganese ion in the ternary product with the required nickel content is 1-8:1-3:1-3.

8. The method for regenerating nickel-cobalt-manganese ternary positive electrode material using waste lithium batteries as claimed in claim 1, characterized in that: The molar ratio of nickel ion, cobalt ion and manganese ion in the ternary product with the required nickel content is 1:1:1, 5:2:3 or 8:1:

1.

9. The method for regenerating nickel-cobalt-manganese ternary positive electrode material using waste lithium batteries as claimed in claim 1, characterized in that: Step S4 includes placing the nickel-cobalt-manganese mixed solution into a spray dryer and performing spray granulation using nitrogen as a protective gas to obtain a ternary precursor.

10. The method for regenerating nickel-cobalt-manganese ternary positive electrode material using waste lithium batteries as claimed in claim 1, characterized in that: The high temperature calcination in step S5 includes heating to 700-900° C. at a heating rate of 4-6° C. / min and keeping the temperature for 5-7 hours.

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