A method for recycling waste lithium cobalt oxide positive electrode material

Abstract

The application discloses a recycling method of waste lithium cobalt oxide positive materials and belongs to the technical field of lithium ion battery recycling. The application provides a method for recycling metal elements in waste lithium cobalt oxide positive materials based on metal chloride assisted hydrothermal-solid phase reaction, and the overall process is green and environmentally friendly, the parameter condition is moderate, and the separation efficiency is high, so that efficient recycling of lithium and cobalt resources can be realized. In the method, the leaching rates of Li and Co ions reach the maximum of 95.1% and 94.1% respectively.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery recycling technology, specifically to a method for recycling waste lithium cobalt oxide cathode materials. Background Technology

[0002] With the widespread application of lithium-ion batteries in consumer electronics, new energy vehicles, and energy storage systems, their production and usage continue to grow. However, the large amount of waste generated after lithium-ion batteries complete their life cycle not only poses a risk of environmental pollution but also contains a significant amount of valuable metal resources, such as cobalt, lithium, and nickel. Lithium cobalt oxide (LiCoO2) batteries, in particular, have high cobalt and lithium content; if not properly recycled and disposed of, they will result in resource waste and ecological risks.

[0003] Currently, the main methods for recycling spent lithium-ion batteries include pyrometallurgy, hydrometallurgy, biometallurgy, and combined processes. While pyrometallurgical recycling processes are simple and adaptable, they suffer from high energy consumption, heavy pollution, and easy lithium loss. In hydrometallurgy, traditional acid leaching methods can achieve high recovery rates, but they require large amounts of strong acids and reducing agents, leading to secondary pollution and cost issues. Furthermore, while biometallurgy is environmentally friendly, its slow reaction rate and unstable processes make it difficult to meet industrial-scale requirements.

[0004] Chinese invention patent CN119191392A discloses a method for extracting and recovering metal elements from lithium batteries using a chlorination process. This method involves high-temperature chlorination roasting of waste battery materials in a chlorine atmosphere, followed by staged gasification and sublimation using a Joule heating device, thereby effectively separating and purifying valuable metals with high metal purity control. This method has certain advantages in improving metal conversion efficiency. However, this technical route relies on chlorine gas, and the entire process involves multi-stage temperature control and precise pH adjustment, resulting in stringent operating conditions, complex processes, and high energy consumption, making it difficult to meet the industrial requirements of green environmental protection and low-cost recycling.

[0005] Chinese invention patent CN117577990A discloses a process for recovering cathode powder from lithium-ion batteries. This method utilizes a ternary eutectic solvent system of choline chloride-urea-polyglutamic acid to leach lithium and cobalt ions from lithium cobalt oxide cathode materials under low-temperature conditions, and then recovers cobalt and lithium elements through oxalic acid precipitation and potassium carbonate reaction, respectively. However, the eutectic solvent system used has a complex composition and is sensitive to preparation conditions, posing challenges to process stability and cost control. Furthermore, it still requires multiple chemical precipitation and membrane separation steps, making the overall process complex and resulting in high reagent and energy consumption, thus limiting its potential for large-scale application.

[0006] Therefore, there is an urgent need to develop a waste lithium battery recycling method that features mild process conditions, simple steps, low energy consumption, and the ability to achieve high-value utilization of metal resources. Summary of the Invention

[0007] [Technical Issues]

[0008] The technical problem to be solved by this invention is to provide a method for recycling waste lithium batteries that features mild process conditions, simple steps, low energy consumption, and high-value utilization of metal resources. This invention provides a method for recovering metal elements from waste lithium cobalt oxide cathode materials based on a metal chloride-assisted hydrothermal-solid phase reaction. The overall process is green and environmentally friendly, with mild parameter conditions and high separation efficiency, enabling efficient recovery of lithium and cobalt resources.

[0009] [Technical Solution]

[0010] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0011] In a first aspect, the present invention provides a method for recycling waste lithium cobalt oxide cathode materials, comprising the following steps:

[0012] S1. Process the waste lithium cobalt oxide batteries to obtain waste cathode material powder, calcine it to obtain waste lithium cobalt oxide powder;

[0013] S2. The waste lithium cobalt oxide powder obtained in step S1 is mixed with metal chloride and subjected to hydrothermal reaction. Solid-liquid separation, washing and drying are performed to obtain leachate and solid by-products.

[0014] S3. Adjust the pH of the leachate obtained in step S2, perform solid-liquid separation, washing and drying to obtain lithium-containing leachate and cobalt hydroxide;

[0015] S4. Mix the lithium-containing leachate obtained in step S3 with a precipitant and react them. Collect the precipitate to obtain lithium salt.

[0016] In one embodiment, the processing step S1 includes discharging, dismantling, and stripping the waste lithium cobalt oxide (LiCoO2) battery to obtain waste cathode material powder.

[0017] In one embodiment, the calcination temperature in step S1 is 400~800℃ and the time is 1~8h.

[0018] In one embodiment, the metal chloride in step S2 includes at least one chloride selected from the groups of Ti, Fe, Al, Cr, V, Sn, Zn, Mg, and Ca. Optionally, but not limited to, the metal chloride includes a chloride of metallic Ti. Further, TiCl3 may be selected.

[0019] Preferably, the metal chloride includes a chloride of metallic Ti.

[0020] In one embodiment, the molar ratio of chlorine to waste lithium cobalt oxide powder in the metal chloride of step S2 is (0.3~6.0):1.

[0021] In one embodiment, the molar ratio of chlorine to waste lithium cobalt oxide powder in the metal chloride of step S2 is (0.7~4.5):1.

[0022] In one embodiment, the molar ratio of chlorine to waste lithium cobalt oxide powder in the metal chloride of step S2 is 3:1.

[0023] In one embodiment, the temperature of the hydrothermal reaction in step S2 is 50~300℃, and the reaction time is 0.5~8h.

[0024] In one embodiment, the solid byproduct in step S2 is a solid product containing a metal oxide, metal hydroxide, and / or other metal salt of the metal element in the added metal chloride. The leachate is a solution containing lithium and cobalt ions.

[0025] In one embodiment, the pH in step S3 is 9.0 to 11.0. The method of adjusting the pH is not limited; for example, those skilled in the art can use one or more of sodium hydroxide, potassium hydroxide, and ammonia to adjust the pH to the desired value.

[0026] In one embodiment, the precipitant in step S4 comprises a phosphate. Optionally, but not limited to, the phosphate comprises one or more of sodium phosphate and potassium phosphate.

[0027] In one embodiment, the reaction temperature of the reaction in step S4 is 30~80℃; the drying temperature is 60~100℃.

[0028] In one embodiment, in step S4, the precipitate is washed 2 to 5 times with deionized water and anhydrous ethanol to obtain lithium salt.

[0029] In a second aspect, the present invention provides the application of the recycling method for waste lithium cobalt oxide cathode materials described in the first aspect in the metal recycling of waste lithium cobalt oxide cathode materials.

[0030] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) This invention utilizes metal chlorides to induce LiCoO2 lattice reconstruction and valence state regulation under hydrothermal conditions to achieve mild and efficient leaching of cobalt and lithium elements, avoiding the use of strong organic or inorganic acids in traditional acidic wet processes, significantly reducing the risk of corrosion and secondary pollution, and making the process greener and more environmentally friendly.

[0033] (2) A two-step separation strategy is adopted to achieve stepwise enrichment and high-purity recovery of cobalt and lithium metal resources in waste lithium cobalt oxide, thereby improving extraction efficiency and product quality. In the method of the present invention, when the molar ratio of TiCl3 / waste LiCoO2 reaches 1.0, the leaching rates of Li and Co ions reach the highest, which are 95.1% and 94.1%, respectively.

[0034] (3) The overall process is mild and the conditions are controllable. The raw materials are highly versatile and the equipment requirements are low. It has good industrial feasibility and promotion potential, and is suitable for large-scale application scenarios of waste lithium battery recycling and processing. Attached Figure Description

[0035] Figure 1 This is a flowchart of the method of the present invention;

[0036] Figure 2 These are graphs showing the metal leaching rates obtained in Examples 1-5 of this invention;

[0037] Figure 3 The XRD test results of the waste lithium cobalt oxide powder obtained after discharge, disassembly, and pre-calcination treatment in step S1 of Embodiment 1 of the present invention are as follows:

[0038] Figure 4 The XRD test results are for titanium dioxide, a solid byproduct obtained in S2 of Example 1.

[0039] Figure 5 These are the XRD test results of cobalt hydroxide obtained in S3 of Example 1;

[0040] Figure 6 The results are XRD analysis of the lithium salt product (Li3PO4) obtained in S4 of Example 1. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation of the invention in any way.

[0042] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0043] Methods for detecting the leaching rates of lithium and cobalt ions in metal leachates:

[0044] (1) Disinfection of waste battery cathode material: To calculate the leaching rate of metal elements, it is necessary to analyze and calculate the element content in the waste lithium-ion battery cathode material. First, a sample of waste lithium cobalt oxide powder of a set mass needs to be completely dissolved in aqua regia. Aqua regia is a mixture of hydrochloric acid (HCl) and nitric acid (HNO3) in a volume ratio of 3:1, which can effectively dissolve battery materials containing elements such as lithium and cobalt. By using aqua regia, it can be ensured that all components in the cathode material can be converted into soluble metal salts, preparing for subsequent analysis. The chemical composition in the solution is measured using inductively coupled plasma optical emission spectrometry (ICP-OES). Through ICP-OES analysis, the chemical content of elements such as lithium (Li) and cobalt (Co) in the waste battery cathode material can be obtained, and then the initial concentration C0 of these elements can be calculated, and the corresponding molar concentration i0 can be calculated.

[0045] (2) The chemical composition of the metal leaching solution obtained from step S2 using waste lithium cobalt oxide powder of the same set mass was measured by inductively coupled plasma optical emission spectrometry (ICP-OES). By analyzing the ICP-OES results, the chemical content of elements such as lithium (Li) and cobalt (Co) can be obtained, and the leaching concentration i of these elements can then be calculated. t .

[0046] (3) Calculation of leaching rate: The leaching rate (Ri) of metal ions is calculated using the following equation:

[0047]

[0048] In the formula i t i0 and i0 are the molar concentrations of the leached metal elements and the molar concentrations measured after digestion of waste lithium cobalt oxide powder, respectively.

[0049] Example:

[0050] Example 1

[0051] A method for recovering metal elements from waste lithium cobalt oxide cathode materials based on a metal chloride-assisted hydrothermal-solid phase reaction is as follows:

[0052] S1: Waste lithium cobalt oxide (LiCoO2) batteries are discharged, disassembled, and stripped to obtain waste cathode material powder, which is then pre-calcined at 600℃ for 2 hours to obtain pre-calcined waste lithium cobalt oxide powder.

[0053] S2: Take 5.00g of pre-calcined waste lithium cobalt oxide powder and 7.88g of titanium trichloride (i.e., TiCl3:LiCoO2 molar ratio of 1:1, Cl... - LiCoO2 was thoroughly mixed in a 3:1 ratio, and deionized water was added to 40 mL. The mixture was then transferred to a 100 mL stainless steel high-pressure reactor with a polytetrafluoroethylene liner. The reactor was placed in a high-temperature oven and the temperature was set at 150 °C for 5 hours to carry out a hydrothermal reaction. After the reaction was completed, the reactor was allowed to cool naturally and then removed. The mixture was filtered and separated, and the liquid was collected to obtain a metal leachate (containing lithium and cobalt ions). The precipitate was collected, washed, and dried to obtain the solid byproduct titanium dioxide (TiO2).

[0054] S3: The pH of the metal leaching solution obtained in step S2 was adjusted to 10.3 using 0.5 mol / L sodium hydroxide solution. The mixture was then subjected to solid-liquid separation, and the supernatant was retained as the lithium-containing leaching solution. The precipitate was washed three times with deionized water and anhydrous ethanol, and then dried at 60°C for 12 h to obtain cobalt hydroxide.

[0055] S4: Place the lithium-containing leaching solution obtained in step S3 into a water bath, adjust the temperature of the water bath to 50 ℃, add 0.5 mol / L sodium phosphate (Na3PO4) solution dropwise, and stir continuously to produce a precipitate. After the reaction is complete, separate the precipitate, wash the precipitate three times with deionized water and anhydrous ethanol respectively, and finally place it in an oven at 60 ℃ for 12 h to obtain the lithium salt product.

[0056] Example 2

[0057] A method for recovering metal elements from waste lithium cobalt oxide cathode materials based on a metal chloride-assisted hydrothermal-solid phase reaction is as follows:

[0058] S1: Waste lithium cobalt oxide (LiCoO2) batteries are discharged, disassembled, and stripped to obtain waste cathode material powder, which is then pre-calcined at 600℃ for 2 hours to obtain pre-calcined waste lithium cobalt oxide powder.

[0059] S2: Take 8.75 g of pre-calcined waste lithium cobalt oxide powder and 4.13 g of titanium trichloride (i.e., TiCl3:LiCoO2 molar ratio of 0.3:1, Cl... -The mixture of LiCoO2 (0.9:1) was thoroughly mixed, and deionized water was added to 40 mL. The mixture was then transferred to a 100 mL stainless steel high-pressure reactor with a polytetrafluoroethylene liner. The reactor was placed in a high-temperature oven and the temperature was set at 150 °C for 5 hours to carry out a hydrothermal reaction. After the reaction was completed, the reactor was allowed to cool naturally and then removed. The mixture was filtered and separated, and the liquid was collected to obtain a metal leachate (containing lithium and cobalt ions). The precipitate was collected, washed, and dried to obtain the solid byproduct titanium dioxide (TiO2).

[0060] S3: The pH of the metal leaching solution obtained in step S2 was adjusted to 10.3 using 0.5 mol / L sodium hydroxide solution. The mixture was then subjected to solid-liquid separation, and the supernatant was retained as the lithium-containing leaching solution. The precipitate was washed three times with deionized water and anhydrous ethanol, and then dried at 60°C for 12 h to obtain cobalt hydroxide.

[0061] S4: Place the lithium-containing leaching solution obtained in step S3 into a water bath, adjust the temperature of the water bath to 50 ℃, add 0.5 mol / L sodium phosphate (Na3PO4) solution dropwise, and stir continuously to produce a precipitate. After the reaction is complete, separate the precipitate, wash the precipitate three times with deionized water and anhydrous ethanol respectively, and finally place it in an oven at 60 ℃ for 12 h to obtain the lithium salt product.

[0062] Example 3

[0063] A method for recovering metal elements from waste lithium cobalt oxide cathode materials based on a metal chloride-assisted hydrothermal-solid phase reaction is as follows:

[0064] S1: Waste lithium cobalt oxide (LiCoO2) batteries are discharged, disassembled, and stripped to obtain waste cathode material powder, which is then pre-calcined at 600℃ for 2 hours to obtain pre-calcined waste lithium cobalt oxide powder.

[0065] S2: Take 6.12 g of pre-calcined waste lithium cobalt oxide powder and 6.76 g of titanium trichloride (i.e., TiCl3:LiCoO2 molar ratio of 0.7:1, Cl... - The mixture of LiCoO2 (2.1:1) was thoroughly mixed, and deionized water was added to 40 mL. The mixture was then transferred to a 100 mL stainless steel high-pressure reactor with a polytetrafluoroethylene liner. The reactor was placed in a high-temperature oven and the temperature was set at 150 °C for 5 hours to carry out a hydrothermal reaction. After the reaction was completed, the reactor was allowed to cool naturally and then removed. The mixture was filtered and separated, and the liquid was collected to obtain a metal leachate (containing lithium and cobalt ions). The precipitate was collected, washed, and dried to obtain the solid byproduct titanium dioxide (TiO2).

[0066] S3: The pH of the metal leaching solution obtained in step S2 was adjusted to 10.3 using 0.5 mol / L sodium hydroxide solution. The mixture was then subjected to solid-liquid separation, and the supernatant was retained as the lithium-containing leaching solution. The precipitate was washed three times with deionized water and anhydrous ethanol, and then dried at 60°C for 12 h to obtain cobalt hydroxide.

[0067] S4: Place the lithium-containing leaching solution obtained in step S3 into a water bath, adjust the temperature of the water bath to 50 ℃, add 0.5 mol / L sodium phosphate (Na3PO4) solution dropwise, and stir continuously to produce a precipitate. After the reaction is complete, separate the precipitate, wash the precipitate three times with deionized water and anhydrous ethanol respectively, and finally place it in an oven at 60 ℃ for 12 h to obtain the lithium salt product.

[0068] Example 4

[0069] A method for recovering metal elements from waste lithium cobalt oxide cathode materials based on a metal chloride-assisted hydrothermal-solid phase reaction is as follows:

[0070] S1: Waste lithium cobalt oxide (LiCoO2) batteries are discharged, disassembled, and stripped to obtain waste cathode material powder, which is then pre-calcined at 600℃ for 2 hours to obtain pre-calcined waste lithium cobalt oxide powder.

[0071] S2: Take 3.83 g of pre-calcined waste lithium cobalt oxide powder and 9.05 g of titanium trichloride (i.e., TiCl3:LiCoO2 molar ratio of 1.5:1, Cl... - The mixture of LiCoO2 (4.5:1) was thoroughly mixed, and deionized water was added to 40 mL. The mixture was then transferred to a 100 mL stainless steel high-pressure reactor with a polytetrafluoroethylene liner. The reactor was placed in a high-temperature oven and the temperature was set at 150 °C for 5 hours to carry out a hydrothermal reaction. After the reaction was completed, the reactor was allowed to cool naturally and then removed. The mixture was filtered and separated, and the liquid was collected to obtain a metal leachate (containing lithium and cobalt ions). The precipitate was collected, washed, and dried to obtain the solid byproduct titanium dioxide (TiO2).

[0072] S3: The pH of the metal leaching solution obtained in step S2 was adjusted to 10.3 using 0.5 mol / L sodium hydroxide solution. The mixture was then subjected to solid-liquid separation, and the supernatant was retained as the lithium-containing leaching solution. The precipitate was washed three times with deionized water and anhydrous ethanol, and then dried at 60°C for 12 h to obtain cobalt hydroxide.

[0073] S4: Place the lithium-containing leaching solution obtained in step S3 into a water bath, adjust the temperature of the water bath to 50 ℃, add 0.5 mol / L sodium phosphate (Na3PO4) solution dropwise, and stir continuously to produce a precipitate. After the reaction is complete, separate the precipitate, wash the precipitate three times with deionized water and anhydrous ethanol respectively, and finally place it in an oven at 60 ℃ for 12 h to obtain the lithium salt product.

[0074] Example 5

[0075] A method for recovering metal elements from waste lithium cobalt oxide cathode materials based on a metal chloride-assisted hydrothermal-solid phase reaction is as follows:

[0076] S1: Waste lithium cobalt oxide (LiCoO2) batteries are discharged, disassembled, and stripped to obtain waste cathode material powder, which is then pre-calcined at 600℃ for 2 hours to obtain pre-calcined waste lithium cobalt oxide powder.

[0077] S2: Take 3.10 g of pre-calcined waste lithium cobalt oxide powder and 9.77 g of titanium trichloride (i.e., TiCl3:LiCoO2 molar ratio of 2:1, Cl... - The mixture of LiCoO2 (6:1) was thoroughly mixed, and deionized water was added to 40 mL. The mixture was then transferred to a 100 mL stainless steel high-pressure reactor with a polytetrafluoroethylene liner. The reactor was placed in a high-temperature oven and the temperature was set at 150 °C for 5 hours to carry out a hydrothermal reaction. After the reaction was completed, the reactor was allowed to cool naturally and then removed. The mixture was filtered and separated, and the liquid was collected to obtain a metal leachate (containing lithium and cobalt ions). The precipitate was collected, washed, and dried to obtain the solid byproduct titanium dioxide (TiO2).

[0078] S3: The pH of the metal leaching solution obtained in step S2 was adjusted to 10.3 using 0.5 mol / L sodium hydroxide solution. The mixture was then subjected to solid-liquid separation, and the supernatant was retained as the lithium-containing leaching solution. The precipitate was washed three times with deionized water and anhydrous ethanol, and then dried at 60°C for 12 h to obtain cobalt hydroxide.

[0079] S4: Place the lithium-containing leaching solution obtained in step S3 in a water bath, adjust the temperature of the water bath to 50 ℃, add 0.5 mol / L sodium phosphate (Na3PO4) solution dropwise, and stir continuously to produce a precipitate. After the reaction is complete, separate the precipitate, wash the precipitate three times with deionized water and anhydrous ethanol respectively, and finally place it in an oven to dry at 60 ℃ for 12 h to obtain the lithium salt product (Li3PO4).

[0080] Example 6

[0081] This embodiment calculates and obtains the metal ion leaching rate of the methods described in Examples 1-5, and the results are as follows: Figure 2 As shown.

[0082] Specifically, as shown in Examples 1-5, the amount of TiCl3 added during hydrothermal leaching is a crucial factor affecting leaching efficiency. With increasing TiCl3 dosage, the leaching efficiency of Li and Co ions initially increases, then gradually decreases. When the molar ratio of TiCl3 / waste LiCoO2 cathode material increases from 0.3 to 0.7, the leaching efficiency in the system significantly improves, with the leaching efficiency of Li ions increasing from 40.4% to 80.2%, and Co ions from 25.3% to 63.3%. When the TiCl3 / waste LiCoO2 ratio reaches 1.0, the leaching rates of Li and Co ions reach their highest levels, at 95.1% and 94.1%, respectively. As the TiCl3 / waste LiCoO2 ratio further increases, the leaching rate decreases somewhat; at 1.5, the leaching rates of Li and Co ions still remain above 90%. When the TiCl3 / waste LiCoO2 ratio is further increased to 2, the leaching rate decreases somewhat, but still remains above 85%. This is because when the ratio of TiCl3 / waste LiCoO2 increases, the concentration of TiCl3 in the system increases, making it easier to generate TiO2, thus leading to a higher concentration of Ti in the system. 3+ The reduction in leaching efficiency leads to a decrease in the overall efficiency of the leaching process. However, the technical solution provided by this invention can efficiently recover metal resources from waste lithium cobalt oxide battery cathode materials.

[0083] Example 7

[0084] In this embodiment, the waste lithium cobalt oxide powder obtained after discharge, dismantling, and pre-calcination treatment in Example 1, the solid by-product obtained in step S2, the cobalt hydroxide obtained in step S3, and the lithium salt (Li3PO4) obtained in step S4 were characterized by XRD. The spectral results are as follows: Figure 3 , Figure 4 , Figure 5 as well as Figure 6 As shown in the figure, the cobalt and lithium elements in the original waste lithium cobalt oxide powder were converted into corresponding cobalt-containing oxides and lithium salt products for recovery. That is, after the above experimental treatment, lithium / cobalt elements were successfully recovered, and the metal elements in the added metal chloride were also recovered as by-products, resulting in significant economic benefits.

[0085] As shown in the above embodiments, this invention provides a method for recovering metal elements from waste lithium cobalt oxide cathode materials based on a metal chloride-assisted hydrothermal-solid-phase reaction. The process flow is clear, the operation is simple, and the metal element recovery efficiency is excellent. Experimental results show that, under a suitable TiCl3 addition ratio (e.g., a molar ratio of 1:1), the leaching rates of lithium ions and cobalt ions in waste lithium cobalt oxide cathode materials can reach 95.1% and 94.1%, respectively, demonstrating excellent leaching performance and element utilization. Simultaneously, cobalt ions are recovered as cobalt hydroxide precipitation, while the lithium-containing solution is successfully recovered as Li3PO4 via precipitation, further verifying the practicality and feasibility of this method in the efficient recovery of key metal resources such as cobalt and lithium. Furthermore, the metal chloride (e.g., TiCl3) added to the reaction system can be converted into a resource-utilizable byproduct (TiO2), contributing to a closed-loop resource system and environmental friendliness. The technical solution of this invention has good industrial application prospects and economic value, providing a new, efficient, and low-pollution path for the green recycling of valuable metals from waste lithium-ion batteries.

[0086] Example 8

[0087] In this embodiment, the reaction conditions of Example 1 are the same, that is, the experimental steps are the same as those of Example 1, only the types of metal chlorides used are changed. Ferric chloride (FeCl3), aluminum chloride (AlCl3), stannous chloride (SnCl2), zinc chloride (ZnCl2) and magnesium chloride (MgCl2) are selected respectively, and the molar ratio of chlorine to LiCoO2 is controlled to be 3:1.

[0088] After the hydrothermal reaction was completed, the mixture was naturally cooled to room temperature, and solid-liquid separation was performed to obtain metal leachate and solid byproducts. The concentrations of lithium and cobalt ions in the leachate were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES), and the leaching rates of Li and Co in each system were calculated. The results are shown in Table 1.

[0089] Table 1. Effects of different metal chloride types on the leaching rates of Li and Co.

[0090]

[0091] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for recycling waste lithium cobalt oxide cathode material, characterized in that, Includes the following steps: S1. Waste lithium cobalt oxide batteries are processed to obtain waste cathode material powder, which is then calcined to obtain waste lithium cobalt oxide powder. S2. The waste lithium cobalt oxide powder obtained in step S1 is mixed with metal chloride, subjected to hydrothermal reaction, solid-liquid separation, washed and dried to obtain leachate and solid by-products. S3. Adjust the pH of the leachate obtained in step S2, perform solid-liquid separation, wash and dry to obtain lithium-containing leachate and cobalt hydroxide; S4. Mix the lithium-containing leachate obtained in step S3 with a precipitant and react them. Collect the precipitate, wash and dry it to obtain lithium salt.

2. The method for recycling waste lithium cobalt oxide cathode material according to claim 1, characterized in that, The metal chloride in step S2 includes at least one of the chlorides of metals Ti, Fe, Al, Cr, V, Sn, Zn, Mg, and Ca; preferably, the metal chloride includes the chloride of metal Ti.

3. The method for recycling waste lithium cobalt oxide cathode material according to claim 1, characterized in that, In step S2, the molar ratio of chlorine to waste lithium cobalt oxide powder in the metal chloride is (0.3~6.0):

1.

4. The method for recycling waste lithium cobalt oxide cathode material according to claim 3, characterized in that, In step S2, the molar ratio of chlorine to waste lithium cobalt oxide powder in the metal chloride is (0.7~4.5):

1.

5. The method for recycling waste lithium cobalt oxide cathode material according to claim 4, characterized in that, In step S2, the molar ratio of chlorine to waste lithium cobalt oxide powder in the metal chloride is 3:

1.

6. The method for recycling waste lithium cobalt oxide cathode material according to claim 1, characterized in that, The temperature of the hydrothermal reaction in step S2 is 50~300℃, and the reaction time is 0.5~8h.

7. The method for recycling waste lithium cobalt oxide cathode material according to claim 1, characterized in that, The pH value in step S3 is 9.0~11.

0.

8. The method for recycling waste lithium cobalt oxide cathode material according to claim 1, characterized in that, The precipitant in step S4 includes phosphate.

9. The application of the recycling method of any one of claims 1-8 for waste lithium cobalt oxide cathode materials in the metal recycling of waste lithium cobalt oxide cathode materials.

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