Waste lithium ion battery recovery method
By using eutectic solvent and resin separation technology, the problems of environmental pollution and low economic efficiency in lithium-ion battery recycling have been solved, achieving efficient and environmentally friendly heavy metal recycling and reducing energy consumption and production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-30
- Publication Date
- 2026-04-17
AI Technical Summary
Existing lithium-ion battery recycling methods suffer from environmental pollution and low economic efficiency, especially pyrometallurgical and hydrometallurgical methods, which cannot efficiently recover high-value metals from lithium-ion batteries.
Waste lithium-ion battery cathode powder was leached using a eutectic solvent (shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride), combined with ultrasonic dispersion and heating stirring. Subsequently, metal ions were separated by a strong acidic cation exchange resin and a chelating resin to obtain a leachate rich in heavy metals.
The leaching rate of heavy metals (such as nickel, cobalt, and manganese) is increased at lower leaching temperatures, reducing energy consumption and the leaching of impurity metals, avoiding the generation of large amounts of wastewater, and lowering production costs.
Smart Images
Figure SMS_1 
Figure SMS_2
Abstract
Description
Technical Field
[0001] This invention relates to the field of recycling technology for waste lithium batteries, and more specifically, to a method for recycling waste lithium-ion batteries. Background Technology
[0002] Lithium-ion batteries, due to their high energy density, long cycle life, high operating voltage, and lack of memory effect, are widely used in mobile phones, laptops, electric vehicles, energy storage systems, and other fields, making them an important component of the modern electronics and new energy industries. Currently, the lithium battery industry is in a phase of rapid growth, particularly driven by the expanding new energy vehicle market and the rapid development of energy storage, resulting in explosive growth in demand for lithium-ion batteries. However, the healthy lifespan of lithium-ion batteries is typically only 6-8 years. Early lithium-ion batteries have already been retired, and with the rapid development in recent years, the number of retired lithium-ion batteries will increase dramatically in the near future. The heavy metals such as lithium, nickel, and cobalt in discarded lithium-ion batteries, if not properly disposed of, can pollute soil and water. Furthermore, these heavy metals are resources with limited reserves; recycling them can alleviate raw material supply pressures, reduce dependence on scarce minerals, and prevent environmental pollution.
[0003] Currently, the main recycling methods for spent lithium-ion batteries are pyrometallurgical recycling and hydrometallurgical recycling. Pyrometallurgical recycling involves high-temperature melting of the battery to separate metal alloys, suitable for handling complex batteries, but it is inefficient, energy-intensive, and cannot recover lithium. Hydrometallurgical recycling dissolves the cathode material in acid / alkali solutions to separate metals such as cobalt and lithium. Its advantages are high recovery rates (cobalt >90%) and good purity, but it requires the treatment of large amounts of wastewater. Although the above two methods have achieved industrial-scale lithium-ion battery recycling, they still suffer from environmental pollution and low economic efficiency. Therefore, how to efficiently and environmentally friendly selectively leach and recover high-value metals from spent lithium-ion batteries has become a current research hotspot.
[0004] In view of this, the present invention is proposed. Summary of the Invention
[0005] The purpose of this invention is to provide a method for recycling waste lithium-ion batteries to solve or improve the above-mentioned technical problems.
[0006] This invention can be implemented as follows: In a first aspect, the present invention provides a method for recycling waste lithium-ion batteries, comprising the following steps: leaching waste lithium-ion battery cathode powder in a eutectic solvent, separating the solid and liquid phases to obtain a leachate rich in heavy metals; wherein the eutectic solvent includes shikimic acid, catechol and tetradecyl dimethyl benzyl ammonium chloride.
[0007] In an optional embodiment, the eutectic solvent comprises shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of (1-5):(1-2):(1-6).
[0008] In an optional embodiment, the solid-liquid ratio of waste lithium-ion battery cathode powder to eutectic solvent is 50g:1L to 100g:1L.
[0009] In an optional embodiment, the waste lithium-ion battery cathode powder includes at least one of waste lithium cobalt oxide battery cathode powder, waste lithium nickel manganese oxide battery cathode powder, and waste lithium nickel cobalt manganese oxide battery cathode powder.
[0010] In an optional embodiment, leaching includes: dispersing waste lithium-ion battery cathode powder in a eutectic solvent under ultrasonic conditions, followed by heating and stirring.
[0011] In an optional embodiment, the ultrasonic dispersion power is 500W~1000W, and the ultrasonic dispersion frequency is 10kHz~60kHz.
[0012] In an optional embodiment, the heating and stirring temperature is 50°C to 85°C, and the heating and stirring time is 5h to 12h.
[0013] In an optional embodiment, the pH of the leachate is adjusted to 3-5, and Li in the leachate is adsorbed by a strongly acidic cation exchange resin. + Ni in the leachate is adsorbed by chelating resin. 2+ Co 2+ and Mn 2+ At least one of the following: desorbing a strongly acidic cation exchange resin and a chelating resin to obtain a lithium solution and a solution containing at least one of nickel, cobalt, and manganese.
[0014] In an optional embodiment, the strongly acidic cation exchange resin includes Dowex 50WX8 resin.
[0015] In an optional embodiment, the chelating resin includes an iminodiacetic acid resin.
[0016] In an optional implementation, desorption is performed using a 5% to 8% hydrochloric acid solution.
[0017] The beneficial effects of this invention include: This invention leaches waste lithium-ion battery cathode powder in a eutectic solvent, comprising shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride, to obtain a leachate rich in heavy metals. Among these eutectic solvents, shikimic acid has strong acidity, which is beneficial for metal leaching; catechol has strong reducing power, which can reduce high-valence metals; and tetradecyl dimethyl benzyl ammonium chloride has strong coordination ability, forming stable complexes with metal ions and improving leaching efficiency. Using shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride together as a eutectic solvent for metal element leaching of waste lithium-ion battery cathode powder can achieve a high leaching rate of heavy metals (such as nickel, cobalt, and manganese) at a lower leaching temperature, while avoiding the leaching of impurity metals, thus avoiding the generation of large amounts of wastewater during impurity removal. Furthermore, this acidic eutectic solvent has low corrosiveness to equipment; compared to the pyrometallurgical methods commonly used in the prior art, it can significantly reduce energy consumption. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0019] The following is a detailed description of the waste lithium-ion battery recycling method provided by the present invention.
[0020] This invention provides a method for recycling waste lithium-ion batteries, comprising the following steps: leaching waste lithium-ion battery cathode powder in a eutectic solvent, separating the solid and liquid phases to obtain a leachate rich in heavy metals. In some optional embodiments, the waste lithium-ion battery cathode powder includes at least one of waste lithium cobalt oxide battery cathode powder, waste lithium nickel manganese oxide battery cathode powder, and waste lithium nickel cobalt manganese oxide battery cathode powder. The waste lithium-ion battery cathode powder can be obtained from waste lithium-ion batteries through pretreatment processes such as crushing, drying and screening, airflow separation, and crushing and separation.
[0021] In this invention, the eutectic solvent includes shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride.
[0022] Among the aforementioned eutectic solvents, shikimic acid has strong acidity, which is beneficial for metal leaching; catechol has strong reducing ability and can reduce high-valence metals; tetradecyl dimethyl benzyl ammonium chloride has strong coordination ability, forming stable complexes with metal ions and improving leaching efficiency. Using shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride together as a eutectic solvent for leaching metal elements from waste lithium-ion battery cathode powder can achieve high leaching rates of heavy metals (such as nickel, cobalt, and manganese) at lower leaching temperatures, while avoiding the leaching of impurity metals and thus avoiding the generation of large amounts of wastewater during impurity removal. Furthermore, this acidic eutectic solvent has low corrosiveness to equipment; compared to the pyrometallurgical methods commonly used in existing technologies, it can significantly reduce energy consumption.
[0023] In some alternative embodiments, the eutectic solvent may include shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of (1-5):(1-2):(1-6). Exemplarily, the molar ratio of shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride may be 2:1:4, 3:1:5, 4:1:3, 2:1:6, 1:1:6, or 5:1:5, or other values within the range of (1-5):(1-2):(1-6).
[0024] If the amount of shikimic acid is too small, it will hinder the leaching of metal ions; if the amount of shikimic acid is too large, it will be wasteful and will also leach out more impurity ions. If the amount of catechol is too small, it will hinder the complete reduction of high-valence metals; if the amount of catechol is too large, it will be wasteful and will also increase the viscosity of the solution, affecting stirring and ion diffusion rates. If the amount of tetradecyl dimethyl benzyl ammonium chloride is too small, it will hinder the leaching of metal ions; if the amount of tetradecyl dimethyl benzyl ammonium chloride is too large, it will be wasteful and will also increase the viscosity of the solution, affecting stirring and ion diffusion rates.
[0025] In some alternative implementations, the solid-liquid ratio of waste lithium-ion battery cathode powder to eutectic solvent can be from 50g:1L to 100g:1L, such as 50g:1L, 60g:1L, 70g:1L, 80g:1L, 90g:1L or 100g:1L, or other values within the range of 50g:1L to 100g:1L.
[0026] In some alternative embodiments, leaching includes: dispersing waste lithium-ion battery cathode powder in a eutectic solvent under ultrasonic conditions, followed by heating and stirring.
[0027] The power of the ultrasonic dispersion can be between 500W and 1000W, such as 500W, 600W, 700W, 800W, 900W, or 1000W, or other values within the range of 500W to 1000W. The frequency of the ultrasonic dispersion can be between 10kHz and 60kHz, such as 10kHz, 20kHz, 30kHz, 40kHz, 50kHz, or 60kHz, or other values within the range of 10kHz to 60kHz.
[0028] In some optional embodiments, the heating and stirring temperature can be 50℃~85℃, such as 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, or 85℃, or other values within the range of 50℃~85℃. The heating and stirring time can be 5h~12h, such as 5h, 6h, 7h, 8h, 9h, 10h, 11h, or 12h, or other values within the range of 5h~12h.
[0029] The ultrasonic dispersion described above allows for the uniform dispersion of waste lithium-ion battery cathode powder in a eutectic solvent; further, the heating and stirring described above allows for the removal of metals (such as Ni) from the waste lithium-ion battery cathode powder. 2+ Co 2+ and Mn 2+ At least one of them and Li + The metals were fully leached into a eutectic solvent. Then, the solution was filtered while hot to obtain a leachate rich in heavy metals.
[0030] Furthermore, the pH of the leachate is adjusted to 3-5, and Li in the leachate is adsorbed by a strongly acidic cation exchange resin. + Ni in the leachate is adsorbed by chelating resin. 2+ Co 2+ and Mn 2+ At least one of the following: desorbing a strongly acidic cation exchange resin and a chelating resin to obtain a lithium solution and a solution containing at least one of nickel, cobalt, and manganese.
[0031] In some alternative implementations, hydrochloric acid can be used to adjust the pH of the leachate to 3-5, such as 3, 3.5, 4, 4.5 or 5, or other values within the range of 3-5.
[0032] In some alternative embodiments, the strongly acidic cation exchange resin may include Dowex 50WX8 resin to adsorb Li in the leachate. + Chelating resins may include iminodiacetic acid resins to adsorb Ni from the leachate. 2+ Co 2+ and Mn 2+ At least one of them.
[0033] Through the adsorption of the above-mentioned resin, metal ions in the leachate can be separated from the eutectic solvent, and the separated eutectic solvent can be reused.
[0034] In some alternative embodiments, desorption can be performed using a 5% to 8% (e.g., 5%, 6%, 7%, or 8%) hydrochloric acid solution to remove the Ni adsorbed by the resin. 2+ Co 2+ and Mn 2+ At least one of them and Li + After desorption, a high-purity lithium chloride solution and a nickel-cobalt-manganese chloride solution were obtained.
[0035] In some optional embodiments, the leaching rate of Li and Co in the waste lithium-ion battery cathode powder is not less than 74%, and when the waste lithium-ion battery cathode powder contains Ni and / or Mn, the leaching rate of Ni and / or Mn is not less than 80%; the content of Fe in the leachate is not more than 96 mg / L, the content of Cu is not more than 75 mg / L, the content of Zn is not more than 83 mg / L, and the content of Al is not more than 88 mg / L.
[0036] In some preferred embodiments, the leaching rate of Li in the waste lithium-ion battery cathode powder is not less than 75%, and the leaching rate of Co is not less than 74.5%; when the waste lithium-ion battery cathode powder contains Ni, the leaching rate of Ni is not less than 86%; when the waste lithium-ion battery cathode powder contains Mn, the leaching rate of Mn is not less than 82%. The content of Fe in the leachate does not exceed 65 mg / L, the content of Cu does not exceed 46 mg / L, the content of Zn does not exceed 75 mg / L, and the content of Al does not exceed 67 mg / L.
[0037] The features and performance of the present invention will be further described in detail below with reference to embodiments.
[0038] Example 1 This embodiment provides a method for recycling waste lithium-ion batteries, including the following steps: S1: 10 kg of waste nickel-cobalt-manganese lithium oxide batteries are pretreated by crushing, drying and screening, air separation and crushing separation to obtain waste lithium-ion battery cathode powder. S2: Weigh 50g of pretreated waste lithium-ion battery cathode powder and ultrasonically disperse it in 1L of eutectic solvent. The ultrasonic power is 500W and the ultrasonic frequency is 30kHz. Then, stir at 65℃ for 8h and filter while hot to obtain a leachate rich in heavy metals. The eutectic solvent is composed of shikimic acid, catechol and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of 2:1:4.
[0039] S3: Add hydrochloric acid to the cooled, heavy metal-rich leachate to adjust the pH to 3, stir, and then adsorb Li through a strongly acidic cation exchange resin (Dowex 50WX8). + Ni is then adsorbed through chelating resins (such as iminodiacetic acid resins). 2+ Co 2+ and Mn 2+ The metal ions were separated from the eutectic solvent. Finally, the resin was desorbed with 6% hydrochloric acid solution to obtain lithium chloride solution and nickel cobalt manganese chloride solution, respectively.
[0040] Example 2 This embodiment provides a method for recycling waste lithium-ion batteries, including the following steps: S1: 10 kg of waste nickel-cobalt-manganese lithium oxide batteries are pretreated by crushing, drying and screening, air separation and crushing separation to obtain waste lithium-ion battery cathode powder. S2: Weigh 50g of pretreated waste lithium-ion battery cathode powder and ultrasonically disperse it in 1L of eutectic solvent. The ultrasonic power is 600W and the ultrasonic frequency is 40kHz. Then, stir at 70℃ for 6h and filter while hot to obtain a leachate rich in heavy metals. The eutectic solvent is composed of shikimic acid, catechol and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of 3:1:5.
[0041] S3: Add hydrochloric acid to the cooled, heavy metal-rich leachate to adjust the pH to 4, stir, and then adsorb Li using a strongly acidic cation exchange resin (Dowex 50WX8). + Ni is then adsorbed through chelating resins (such as iminodiacetic acid resins). 2+ Co 2+ and Mn 2+ The metal ions were separated from the eutectic solvent. Finally, the resin was desorbed with 5% hydrochloric acid solution to obtain lithium chloride solution and nickel cobalt manganese chloride solution, respectively.
[0042] Example 3 This embodiment provides a method for recycling waste lithium-ion batteries, including the following steps: S1: Mix 5kg of waste nickel-cobalt-manganese lithium batteries and 5kg of waste cobalt-cobalt lithium batteries, and obtain waste lithium-ion battery cathode powder through pretreatment such as crushing, drying and screening, airflow separation and crushing separation. S2: Weigh 50g of pretreated waste lithium-ion battery cathode powder and ultrasonically disperse it in 1L of eutectic solvent. The ultrasonic power is 600W and the ultrasonic frequency is 30kHz. Then, stir at 70℃ for 6h and filter while hot to obtain a leachate rich in heavy metals. The eutectic solvent is composed of shikimic acid, catechol and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of 4:1:3.
[0043] S3: Add hydrochloric acid to the cooled, heavy metal-rich leachate to adjust the pH to 3.5, stir, and then adsorb Li using a strongly acidic cation exchange resin (Dowex 50WX8). + Ni is then adsorbed through chelating resins (such as iminodiacetic acid resins). 2+ Co 2+ and Mn 2+ The metal ions were separated from the eutectic solvent. Finally, the resin was desorbed with 6% hydrochloric acid solution to obtain lithium chloride solution and nickel cobalt manganese chloride solution, respectively.
[0044] Example 4 This embodiment provides a method for recycling waste lithium-ion batteries, including the following steps: S1: Mix 5kg of waste nickel-cobalt-manganese lithium batteries and 5kg of waste cobalt-cobalt lithium batteries, and obtain waste lithium-ion battery cathode powder through pretreatment such as crushing, drying and screening, airflow separation and crushing separation. S2: Weigh 50g of pretreated waste lithium-ion battery cathode powder and ultrasonically disperse it in 1L of eutectic solvent. The ultrasonic power is 600W and the ultrasonic frequency is 30kHz. Then, stir at 70℃ for 6h and filter while hot to obtain a leachate rich in heavy metals. The eutectic solvent is composed of shikimic acid, catechol and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of 2:1:6.
[0045] S3: Add hydrochloric acid to the cooled, heavy metal-rich leachate to adjust the pH to 4, stir, and then adsorb Li using a strongly acidic cation exchange resin (Dowex 50WX8). + Ni is then adsorbed through chelating resins (such as iminodiacetic acid resins). 2+ Co 2+ and Mn 2+ The metal ions were separated from the eutectic solvent. Finally, the resin was desorbed with 7% hydrochloric acid solution to obtain lithium chloride solution and nickel cobalt manganese chloride solution, respectively.
[0046] Example 5 This embodiment provides a method for recycling waste lithium-ion batteries, including the following steps: S1: 10 kg of waste lithium cobalt oxide batteries are pretreated by crushing, drying and screening, air separation and crushing separation to obtain waste lithium-ion battery cathode powder. S2: Weigh 50g of pretreated waste lithium-ion battery cathode powder and ultrasonically disperse it in 1L of eutectic solvent. The ultrasonic power is 600W and the ultrasonic frequency is 30kHz. Then, stir at 70℃ for 6h and filter while hot to obtain a leachate rich in heavy metals. The eutectic solvent is composed of shikimic acid, catechol and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of 1:1:6.
[0047] S3: Add hydrochloric acid to the cooled, heavy metal-rich leachate to adjust the pH to 5, stir, and then adsorb Li using a strongly acidic cation exchange resin (Dowex 50WX8). + Co is then adsorbed through chelating resins (such as iminodiacetic acid resins). 2+ The metal ions were separated from the eutectic solvent. Finally, the resin was desorbed with 5% hydrochloric acid solution to obtain lithium chloride solution and cobalt chloride solution, respectively.
[0048] Example 6 This embodiment provides a method for recycling waste lithium-ion batteries, including the following steps: S1: 10 kg of waste lithium cobalt oxide batteries are pretreated by crushing, drying and screening, air separation and crushing separation to obtain waste lithium-ion battery cathode powder. S2: Weigh 50g of pretreated waste lithium-ion battery cathode powder and ultrasonically disperse it in 1L of eutectic solvent. The ultrasonic power is 600W and the ultrasonic frequency is 30kHz. Then, stir at 70℃ for 6h and filter while hot to obtain a leachate rich in heavy metals. The eutectic solvent is composed of shikimic acid, catechol and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of 5:1:5.
[0049] S3: Add hydrochloric acid to the cooled, heavy metal-rich leachate to adjust the pH to 3, stir, and then adsorb Li through a strongly acidic cation exchange resin (Dowex 50WX8). + Co is then adsorbed through chelating resins (such as iminodiacetic acid resins). 2+ The metal ions were separated from the eutectic solvent. Finally, the resin was desorbed with 8% hydrochloric acid solution to obtain lithium chloride solution and cobalt chloride solution, respectively.
[0050] Example 7 This embodiment provides a method for recycling waste lithium-ion batteries, including the following steps: S1: 10 kg of waste nickel-cobalt-manganese lithium oxide batteries are pretreated by crushing, drying and screening, air separation and crushing separation to obtain waste lithium-ion battery cathode powder. S2: Weigh 100g of pretreated waste lithium-ion battery cathode powder and ultrasonically disperse it in 1L of eutectic solvent. The ultrasonic power is 800W and the ultrasonic frequency is 10kHz. Then, stir at 50℃ for 12h and filter while hot to obtain a leachate rich in heavy metals. The eutectic solvent is composed of shikimic acid, catechol and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of 5:1.5:2.
[0051] S3: Add hydrochloric acid to the cooled, heavy metal-rich leachate to adjust the pH to 3.5, stir, and then adsorb Li using a strongly acidic cation exchange resin (Dowex 50WX8). + Ni is then adsorbed through chelating resins (such as iminodiacetic acid resins). 2+ Co 2+ and Mn 2+ The metal ions were separated from the eutectic solvent. Finally, the resin was desorbed with 6% hydrochloric acid solution to obtain lithium chloride solution and nickel cobalt manganese chloride solution, respectively.
[0052] Example 8 This embodiment provides a method for recycling waste lithium-ion batteries, including the following steps: S1: 10 kg of waste nickel-cobalt-manganese lithium oxide batteries are pretreated by crushing, drying and screening, air separation and crushing separation to obtain waste lithium-ion battery cathode powder. S2: Weigh 80g of pretreated waste lithium-ion battery cathode powder and ultrasonically disperse it in 1L of eutectic solvent. The ultrasonic power is 1000W and the ultrasonic frequency is 60kHz. Then, stir at 85℃ for 5h and filter while hot to obtain a leachate rich in heavy metals. The eutectic solvent is composed of shikimic acid, catechol and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of 3:2:1.
[0053] S3: Add hydrochloric acid to the cooled, heavy metal-rich leachate to adjust the pH to 4.5, stir, and then adsorb Li using a strongly acidic cation exchange resin (Dowex 50WX8). + Ni is then adsorbed through chelating resins (such as iminodiacetic acid resins). 2+ Co 2+ and Mn 2+ The metal ions were separated from the eutectic solvent. Finally, the resin was desorbed with 6% hydrochloric acid solution to obtain lithium chloride solution and nickel cobalt manganese chloride solution, respectively.
[0054] Example 9 The difference between this embodiment and Embodiment 1 is that, in molar ratio, the eutectic solvent includes shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride in a ratio of 2:3:1.
[0055] Example 10 The difference between this embodiment and Embodiment 1 is that, in molar ratio, the eutectic solvent includes shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride in a ratio of 2:1:8.
[0056] Example 11 The difference between this embodiment and Embodiment 1 is that, in molar ratio, the eutectic solvent includes shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride in a ratio of 6:1:4.
[0057] Comparative Example 1 The difference between this comparative example and Example 1 is as follows: In S2, the eutectic solvent consists of shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of 2:1:0.
[0058] In step S3, hydrochloric acid was added to the cooled leachate rich in heavy metals to adjust the pH to 4, and the solution was stirred. Then, Li was adsorbed through a strongly acidic cation exchange resin (Dowex 50WX8). + Ni is then adsorbed through chelating resins (such as iminodiacetic acid resins). 2+ Co 2+ and Mn 2+ The metal ions were separated from the eutectic solvent. Finally, the resin was desorbed with 5% hydrochloric acid solution to obtain lithium chloride solution and nickel cobalt manganese chloride solution, respectively.
[0059] Comparative Example 2 The difference between this comparative example and Example 1 is that in S2, the eutectic solvent is composed of shikimic acid, catechol and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of 2:0:4.
[0060] Comparative Example 3 The difference between this comparative example and Example 1 is that in S2, the eutectic solvent is composed of shikimic acid, catechol and tetradecyl dimethyl benzyl ammonium chloride in a molar ratio of 0:1:4.
[0061] Comparative Example 4 The difference between this comparative example and Example 1 is that in S2, 50g of pretreated waste lithium-ion battery cathode powder was weighed, 1L of 3mol / L sulfuric acid was added, 1.3 times the theoretical amount of hydrogen peroxide was added, and the mixture was stirred at 80°C for 8 hours. The mixture was then filtered while hot to obtain a leachate rich in heavy metals.
[0062] Comparative Example 5 The difference between this comparative example and Example 1 is that shikimic acid is replaced with oxalic acid.
[0063] Comparative Example 6 The difference between this comparative example and Example 1 is that tetradecyl dimethyl benzyl ammonium chloride is replaced with dodecyl trimethyl ammonium bromide.
[0064] Comparative Example 7 The difference between this comparative example and Example 1 is that catechol is replaced with phenol.
[0065] Test case The leachates obtained in Examples 1-11 and Comparative Examples 1-7 were tested. Specifically, each leachate was brought to a final volume of 1L, and then 1ml was taken with a pipette to dilute it 250 times. The composition of the leachate was measured using ICP to obtain the leaching rates of lithium, nickel, cobalt and manganese, as well as the impurity content in the leachate. The results are shown in Tables 1 and 2.
[0066] Table 1 Comparison of Metal Leaching Rates
[0067] Table 2 Comparison of Impurity Content in Leachate
[0068] As shown in Table 1, compared to Comparative Examples 1-3, leaching the waste lithium-ion battery cathode powder using a eutectic solvent composed of shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride resulted in leaching rates of valuable metals Li and Co exceeding 74% (when the waste lithium-ion battery cathode powder contained Ni and Mn, the leaching rates of Ni and Mn could reach over 80%). Comparative Example 3 failed to effectively leach valuable metals because it lacked shikimic acid, resulting in an acid-free leaching process for the waste lithium-ion battery cathode powder.
[0069] Combined with Table 2, the use of a eutectic solvent composed of shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride to leach waste lithium-ion battery cathode powder can significantly reduce the content of impurities in the leachate compared to the traditional sulfuric acid + hydrogen peroxide leaching method (Comparative Example 4). This can save a lot of auxiliary materials for subsequent impurity removal and refining processes and reduce production costs.
[0070] As can be seen from Examples 1 and 9-11, when the amount of components in the eutectic solvent changes, it will lead to a decrease in the metal leaching rate (Examples 9 and 10) or an increase in the impurity leaching rate (Examples 9-11).
[0071] As can be seen from Examples 1 and Comparative Examples 5-7, when the composition in the eutectic solvent changes, it can lead to a decrease in the metal leaching rate (Comparative Examples 6 and 7) or an increase in the impurity leaching rate (Comparative Example 5).
[0072] In summary, this invention improves the leaching rate of heavy metals such as nickel, cobalt, and manganese by using a eutectic solvent for leaching, while avoiding the leaching of impurity metals and thus preventing the generation of large amounts of wastewater during impurity removal. By using ion exchange resin to separate metal ions from the eutectic solvent, the eutectic solvent is recovered for reuse, and a pure metal solution is obtained.
[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for recycling waste lithium-ion batteries, characterized in that, The process includes the following steps: leaching waste lithium-ion battery cathode powder in a eutectic solvent, separating the solid and liquid phases to obtain a leachate rich in heavy metals; wherein the eutectic solvent includes shikimic acid, catechol, and tetradecyl dimethyl benzyl ammonium chloride.
2. The method for recycling waste lithium-ion batteries according to claim 1, characterized in that, According to the molar ratio, the eutectic solvent comprises (1~5):(1~2):(1~6) the shikimic acid, the catechol, and the tetradecyl dimethyl benzyl ammonium chloride.
3. The method for recycling waste lithium-ion batteries according to claim 1, characterized in that, The solid-liquid ratio of the waste lithium-ion battery cathode powder to the eutectic solvent is 50g:1L to 100g:1L.
4. The method for recycling waste lithium-ion batteries according to claim 1, characterized in that, The waste lithium-ion battery cathode powder includes at least one of waste lithium cobalt oxide battery cathode powder, waste lithium nickel manganese oxide battery cathode powder, and waste lithium nickel cobalt manganese oxide battery cathode powder.
5. The method for recycling waste lithium-ion batteries according to claim 1, characterized in that, Leaching includes: The waste lithium-ion battery cathode powder is dispersed in the eutectic solvent under ultrasonic conditions, and then heated and stirred.
6. The method for recycling waste lithium-ion batteries according to claim 5, characterized in that, The ultrasonic dispersion power is 500W~1000W, and the ultrasonic dispersion frequency is 10kHz~60kHz.
7. The method for recycling waste lithium-ion batteries according to claim 5, characterized in that, The heating and stirring temperature is 50℃~85℃, and the heating and stirring time is 5h~12h.
8. The method for recycling waste lithium-ion batteries according to any one of claims 1 to 7, characterized in that, adjusting the pH of the leachate to 3-5, then adsorbing Li in the leachate by a strong acid cation exchange resin + , adsorbing at least one of Ni 2+ , Co 2+ and Mn 2+ in the leachate by a chelating resin; desorbing the strong acid cation exchange resin and the chelating resin to obtain a lithium solution and a solution containing at least one of Ni, Co and Mn.
9. The method for recycling waste lithium-ion batteries according to claim 8, characterized in that, The strongly acidic cation exchange resin includes Dowex 50WX8 resin; And / or, the chelating resin includes an iminodiacetic acid resin.
10. The method for recycling waste lithium-ion batteries according to claim 8, characterized in that, Desorption was performed using a 5%–8% hydrochloric acid solution.