Selective lithium extraction method for lithium battery recovery and use thereof

Abstract

The present application relates to the technical field of recovery of waste lithium-ion batteries, and particularly relates to a selective lithium extraction method for lithium battery recovery and the use thereof. The selective lithium extraction method for lithium battery recovery comprises the following steps: S1, disassembling and screening; S2, acidification of mixed waste; S3, aging of the mixed waste under a constant temperature; S4, sintering and lithium leaching; S5, impurity removal and filtration of a filtrate; and S6, pH adjustment of the resulting lithium extraction liquid. The selective lithium extraction method for lithium battery recovery of the present application is different from conventional lithium extraction recovery methods, has relatively high selectivity during the impurity removal process, greatly reduces the time required by the impurity removal process and the operation difficulty, also simplifies the preparation process of lithium sulfate, ultimately greatly improves the lithium extraction efficiency and quality, and reduces the cost of a high-purity lithium extraction process; and the method has great market prospects.

Description

A method for selectively extracting lithium from lithium batteries and its application Technical Field

[0001] The present application relates to the technical field of waste lithium-ion battery recycling, and in particular to a method for selectively extracting lithium for lithium battery recycling and its application. Background Art

[0002] In recent years, the continued development and market expansion of electric vehicles, electronic devices, and energy storage have promoted the widespread use of lithium-ion batteries. Lithium-ion batteries, due to their relatively high energy density, low cost, and excellent safety performance, have seen explosive growth in their use. Lithium-ion batteries undergo approximately 500-1000 charge-discharge cycles in actual use, with a lifespan of 3-5 years. Consequently, China will continue to experience a surge in the scrapping of used lithium batteries in recent years. The main components of a lithium battery are the positive electrode (lithium-ion powder, binder, and aluminum foil), the negative electrode (graphite, binder, and copper foil), a separator, an electrolyte, and a casing. Because lithium-ion batteries contain higher valuable metal content than their original ore, and because the price of raw materials for lithium batteries has risen sharply, recycling used lithium batteries has become a trend.

[0003] However, a large number of waste lithium battery materials contain rich valuable elements such as lithium, nickel, and cobalt. Traditional recovery and separation methods use full wet leaching to recover valuable metals. That is, after the waste batteries are discharged, crushed, and roasted, acid is used to dissolve the valuable metals from the positive electrode material and leach them together. The leachate is then subjected to impurity removal, extraction and other processes to recover nickel, cobalt, and manganese. Lithium is obtained by adding a precipitant to the leachate, and the selectivity of the impurity removal process is low.

[0004] Therefore, in order to solve the above problems, the present application provides a method for selective lithium extraction for lithium battery recovery, which has strong selectivity in the impurity removal process and greatly improves the efficiency and quality of lithium extraction. Summary of the Invention

[0005] In order to solve the above problems, the first aspect of the present application provides a method for selective lithium extraction for lithium battery recovery, which includes the following steps: S1: disassembly and screening: discharging, disassembling, and classifying the lithium battery to obtain mixed waste of positive and negative electrodes; S2: acidification: adding inorganic acid to the mixed waste of positive and negative electrodes while stirring, and removing the remaining inorganic acid after the soaking is completed, and chopping and screening the mixed waste of positive and negative electrodes; S3: heat preservation and aging: heating the mixed waste after sieving, and heat preservation and aging for 20-30h; S4: sintering and lithium leaching: after aging, The mixed waste is calcined and sintered. After the sintering is completed, the sintered material is cooled to room temperature and then added to a dilute sulfuric acid aqueous solution to leach the lithium sulfate solution and precipitate the leaching residue; S5: impurity removal and filtration: modified adsorption composite particles are added to the lithium sulfate solution, stirred at a speed of 200-400 rpm for 10-20 hours, and filtered through microfiltration to obtain a first filtrate. An impurity remover is added to the first filtrate, and after the impurity removal is completed, a second filtrate is filtered through microfiltration to obtain a second filtrate; S6: pH adjustment: the pH of the second filtrate is adjusted to 6-7 to obtain a lithium sulfate recovery solution.

[0006] As a preferred solution, the mixed waste of the positive and negative electrodes has a lithium content of 4-8%, a Ni content of 15-30%, a Co content of 3-8%, and a Mn content of 12-20%, calculated by mass percentage.

[0007] As a preferred solution, the mixed waste of the positive and negative electrodes has a lithium content of 5-7%, a Ni content of 20-25%, a Co content of 4-6%, and a Mn content of 15-18% by mass.

[0008] As a preferred solution, the inorganic acid is any one of dilute sulfuric acid, dilute hydrochloric acid, and dilute nitric acid.

[0009] As a preferred solution, the inorganic acid is dilute sulfuric acid.

[0010] As a preferred solution, the concentration of the dilute sulfuric acid is 20-50 wt%.

[0011] As a preferred solution, the mass ratio of the inorganic acid to the mixed waste of the positive and negative electrodes is (0.6-1.2):1.

[0012] As a preferred solution, the mass ratio of the inorganic acid to the mixed waste of the positive and negative electrodes is 1.1:1.

[0013] As a preferred solution, the mixed waste of positive and negative electrodes is chopped and sieved with a mesh size of 800-2000 meshes.

[0014] As a preferred solution, the mixed waste of positive and negative electrodes is chopped and sieved to a mesh size of 1000-1600 meshes.

[0015] As a preferred solution, the mixed waste of positive and negative electrodes is chopped and sieved with a mesh size of 1200 meshes.

[0016] As a preferred solution, the temperature of the thermal insulation aging is 50-60°C.

[0017] As a preferred solution, the temperature of the thermal insulation aging is 55°C.

[0018] As a preferred solution, the calcination temperature is 500-800°C.

[0019] As a preferred solution, the calcination temperature is 600-750°C.

[0020] As a preferred solution, the calcination time is 50-160 minutes.

[0021] As a preferred solution, the calcination time is 80-140 minutes.

[0022] As a preferred solution, the mass ratio of the sintering material to the dilute sulfuric acid aqueous solution in S4 is (1-1.5):(5-8).

[0023] As a preferred solution, the mass ratio of the sintering material to the dilute sulfuric acid aqueous solution in S4 is (1-1.2):(6-8).

[0024] As a preferred solution, the leaching rate of lithium sulfate in S4 is 98.0-99.9%.

[0025] As a preferred solution, the mass concentration of the dilute sulfuric acid aqueous solution is 5-20%.

[0026] As a preferred solution, the mass ratio of the lithium sulfate solution to the modified adsorption composite particles is 1:(0.01-0.1).

[0027] As a preferred solution, the mass ratio of the lithium sulfate solution to the modified adsorption composite particles is 1:0.05.

[0028] As a preferred solution, the preparation method of the modified adsorption composite particles includes the following steps: S1: adding succinic anhydride, 3-aminopropyltriethoxysilane, manganese dioxide and nickel oxide to a DMF solution, heating and stirring at a water bath temperature of 40-45°C for 3-4 hours; S2: then adding zinc nitrate, cooling to room temperature, mixing and stirring to completely dissolve to obtain a mixed solution; S3: adding a DMF solution containing imidazole dropwise to the above mixed solution, heating to 60-65°C, and keeping the mixture warm for 5-8 hours at a stirring speed of 60-120 r / min, during which the pH is maintained at 6-7, to obtain the modified adsorption composite particles.

[0029] In the present application, the above-mentioned modification of the composite particles can greatly improve its selective adsorption effect on Mn and Ni, and can be directly selectively filtered out in the subsequent filtration process, thereby greatly improving the selectivity and efficiency of lithium extraction and improving the purity of lithium extraction. In the present application, by modifying the groups on the surface of the above-mentioned manganese dioxide and nickel oxide, composite adsorption particles wrapped by skeleton particles are generated in the subsequent reaction process. The presence of the skeleton particles and the gaps formed between them and the oxide particles can effectively enhance the selective adsorption effect on Mn and Ni through the vacancy effect, thereby greatly reducing the use of precipitants in the subsequent impurity removal process. The manganese dioxide and nickel oxide are bound to the skeleton particles by coordination bonds, and no new impurities are introduced in the above-mentioned adsorption process, thereby ensuring the final purity of lithium extraction.

[0030] As a preferred solution, the average particle size of the manganese dioxide and nickel oxide is 0.1-0.15 μm.

[0031] As a preferred solution, the mass ratio of succinic anhydride, 3-aminopropyltriethoxysilane, manganese dioxide and nickel oxide is (4-5): (2-4): (0.5-2): (0.5-2).

[0032] As a preferred solution, the amount of zinc nitrate added is 1-2 wt % of the solution obtained in S1.

[0033] As a preferred solution, the imidazole is 2-methylimidazole.

[0034] As a preferred solution, the mass ratio of the imidazole to zinc nitrate is (2-3):1.

[0035] The applicant has found that only when the ratio of the above-mentioned raw materials is adopted can the ideal configuration of the composite adsorption particles be guaranteed. When the content of imidazole and zinc nitrate is low or the content of manganese dioxide and nickel oxide is high, it is easy to form agglomerated particles of a single skeleton particle and oxide particles, and the skeleton particles are actually completely wrapped in the interior of the oxide particles, and no effective adsorption holes can be formed, but the adsorption selectivity and adsorption efficiency of the composite adsorption particles are greatly reduced. And if the reaction time is not enough, the skeleton particles cannot reach their appropriate particle size, and are easily in a deformed state due to the incorporation of oxide particles during the reaction, and then the growth of the skeleton cannot continue, which ultimately affects the selective adsorption efficiency and the final lithium extraction purity.

[0036] As a preferred solution, the impurity remover is lime or lime milk.

[0037] As a preferred solution, the mass ratio of the first filtrate to the impurity remover is 1:(0.05-0.1).

[0038] The second aspect of the present application provides an application of the above-mentioned method for selectively extracting lithium from lithium batteries for recycling, including the application of the method for selectively extracting lithium from lithium batteries for recycling in a lithium battery recycling and reuse process.

[0039] This application has the following beneficial effects:

[0040] 1. The method for selective lithium extraction for lithium battery recovery provided in this application is different from previous lithium extraction and recovery methods. It has strong selectivity in the impurity removal process, greatly reducing the time and operation difficulty of the impurity removal process, while simplifying the preparation process of lithium sulfate. Ultimately, it greatly improves the efficiency and quality of lithium extraction, reduces the cost of high-purity lithium extraction process, and has very excellent market prospects.

[0041] 2. The present application provides a method for selective lithium extraction for lithium battery recovery, which can greatly improve the selective adsorption of Mn and Ni by modifying the composite particles, and can directly and selectively filter them out in the subsequent filtration process, thereby greatly improving the selectivity and efficiency of lithium extraction and improving the purity of lithium extraction. By modifying the groups on the surface of manganese dioxide and nickel oxide, composite adsorption particles wrapped by skeleton particles are generated in the subsequent reaction process. The presence of the skeleton particles and the gaps formed between them and the oxide particles can effectively enhance the selective adsorption effect of Mn and Ni through the vacancy effect, thereby significantly reducing the use of precipitants in the subsequent impurity removal process.

[0042] 3. The method for selective lithium extraction from lithium battery recovery provided in this application can only ensure the ideal configuration of the composite adsorption particles when the above-mentioned raw material ratio scheme is adopted. When the content of imidazole and zinc nitrate is low or the content of manganese dioxide and nickel oxide is high, it is easy to form agglomerated particles of single skeleton particles and oxide particles, which actually completely wraps the skeleton particles inside the oxide particles, unable to form any effective adsorption holes, but greatly reduces the adsorption selectivity and adsorption efficiency of the composite adsorption particles. Moreover, if the reaction time is insufficient, the skeleton particles cannot reach their appropriate particle size and are easily deformed during the reaction due to the incorporation of oxide particles, making it impossible to continue the growth of the skeleton, which ultimately affects the selective adsorption efficiency and the final lithium extraction purity.

[0043] 4. The present application provides a method for selective lithium extraction for lithium battery recovery. The high-purity lithium sulfate solution finally obtained can be directly used to obtain battery-grade lithium sulfate products through evaporation and crystallization, and the circulating water and industrial sulfuric acid obtained during the evaporation and crystallization process can be recycled in the process of the present application. DETAILED DESCRIPTION

[0044] The following text further illustrates and demonstrates the technical solutions described in the above-mentioned summary of the invention in the form of specific implementation plans. The following examples are merely practical examples used to illustrate and explain the technical solutions in the specification and should not limit the scope of the claims to be protected by this application. All technical products based on the technical solutions described in the summary of the invention in this application should be included in the scope of protection to be protected by this application.

[0045] In the following examples, unless otherwise specified, the raw materials are all commercially available products or can be prepared by methods well known to those skilled in the art.

[0046] Example 1

[0047] The first aspect of Example 1 provides a method for selective lithium extraction for lithium battery recovery, which includes the following steps: S1: disassembly and screening: discharging, disassembling, and classifying the lithium battery to obtain mixed waste of positive and negative electrodes; S2: acidification: adding inorganic acid to the mixed waste of positive and negative electrodes while stirring, and removing the remaining inorganic acid after the soaking is completed, and chopping and sieving the mixed waste of positive and negative electrodes; S3: heat preservation and aging: heating the mixed waste after sieving, and heat preservation and aging for 28 hours; S4: sintering and lithium leaching: roasting the mixed waste after aging Sintering. After the sintering is completed, the sintered material is cooled to room temperature and then added to a dilute sulfuric acid aqueous solution to leach the lithium sulfate solution and precipitate the leaching residue, and the leaching is cycled for 4 times; S5: impurity removal and filtration: modified adsorption composite particles are added to the lithium sulfate solution, stirred at 300 rpm for 12 hours, and then filtered through 0.1 μm microfiltration to obtain a first filtrate, an impurity remover is added to the first filtrate, and after the impurity removal is completed, a second 0.1 μm microfiltration is performed to obtain a second filtrate; S6: pH adjustment: the pH of the second filtrate is adjusted to 6.5 to obtain a lithium sulfate recovery solution.

[0048] In the mixed waste of positive and negative electrodes, the lithium content is 6.02%, the Ni content is 22.41%, the Co content is 5.65%, and the Mn content is 17.87%, calculated by mass percentage.

[0049] The inorganic acid is dilute sulfuric acid, and the concentration of the dilute sulfuric acid is 30 wt %.

[0050] The mass ratio of the inorganic acid to the mixed waste of the positive and negative electrodes is 1.1:1.

[0051] The mixed waste of positive and negative electrodes is chopped and sieved with a mesh size of 1200 meshes.

[0052] The temperature for thermal insulation and aging is 55°C.

[0053] The calcination temperature is 700°C and the calcination time is 100 minutes.

[0054] The mass ratio of the sintering material to the dilute sulfuric acid aqueous solution in S4 is 1:6.5.

[0055] The leaching rate of lithium sulfate in S4 was 99.3%.

[0056] The mass concentration of the dilute sulfuric acid aqueous solution is 10%.

[0057] The mass ratio of lithium sulfate solution to modified adsorption composite particles is 1:0.05.

[0058] The preparation method of modified adsorption composite particles includes the following steps, calculated in parts by mass: S1: 4 parts of succinic anhydride, 3 parts of 3-aminopropyltriethoxysilane, 1 part of manganese dioxide and 1.2 parts of nickel oxide are mixed and added to 100 parts of DMF solution, and heated and stirred at a water bath temperature of 45°C for 4 hours; S2: 2wt% of zinc nitrate in the S1 solution is then added, the temperature is lowered to room temperature of 25°C, and the mixture is mixed and stirred until it is completely dissolved to obtain a mixed solution; S3: 50 parts of DMF solution containing 2-methylimidazole (the mass ratio of 2-methylimidazole to zinc nitrate is 2.5:1) is added dropwise to the above-mentioned mixed solution, the temperature is raised to 65°C, and the mixture is kept warm for 7.5 hours at a stirring speed of 100 r / min, during which the pH is maintained at 6.5, thereby obtaining modified adsorption composite particles.

[0059] The average particle size of manganese dioxide and nickel oxide was 0.1 μm.

[0060] The impurity remover is lime; the mass ratio of the first filtrate to the impurity remover is 1:0.08.

[0061] Example 2

[0062] The first aspect of Example 2 provides a method for selective lithium extraction for lithium battery recovery, which includes the following steps: S1: disassembly and screening: discharging, disassembling, and classifying the lithium battery to obtain mixed waste of positive and negative electrodes; S2: acidification: adding inorganic acid to the mixed waste of positive and negative electrodes while stirring, and removing the remaining inorganic acid after the soaking is completed, and chopping and sieving the mixed waste of positive and negative electrodes; S3: heat preservation and aging: heating the mixed waste after sieving, and heat preservation and aging for 28 hours; S4: sintering and lithium leaching: roasting the mixed waste after aging Sintering. After the sintering is completed, the sintered material is cooled to room temperature and then added to a dilute sulfuric acid aqueous solution to leach the lithium sulfate solution and precipitate the leaching residue, and the leaching is cycled for 4 times; S5: impurity removal and filtration: modified adsorption composite particles are added to the lithium sulfate solution, stirred at 300 rpm for 12 hours, and then filtered through 0.1 μm microfiltration to obtain a first filtrate, an impurity remover is added to the first filtrate, and after the impurity removal is completed, a second 0.1 μm microfiltration is performed to obtain a second filtrate; S6: pH adjustment: the pH of the second filtrate is adjusted to 6.5 to obtain a lithium sulfate recovery solution.

[0063] In the mixed waste of positive and negative electrodes, the lithium content is 5.98%, the Ni content is 23.43%, the Co content is 5.15%, and the Mn content is 16.97%, calculated by mass percentage.

[0064] The inorganic acid is dilute sulfuric acid, and the concentration of the dilute sulfuric acid is 40 wt %.

[0065] The mass ratio of the inorganic acid to the mixed waste of the positive and negative electrodes is 1:1.

[0066] The mixed waste of positive and negative electrodes is chopped and sieved with a mesh size of 1000 mesh.

[0067] The temperature for thermal insulation and aging is 60°C.

[0068] The calcination temperature is 750°C and the calcination time is 90 minutes.

[0069] The mass ratio of the sintering material to the dilute sulfuric acid aqueous solution in S4 is 1:6.

[0070] The leaching rate of lithium sulfate in S4 was 99.2%.

[0071] The mass concentration of the dilute sulfuric acid aqueous solution is 10%.

[0072] The mass ratio of lithium sulfate solution to modified adsorption composite particles is 1:0.05.

[0073] The preparation method of modified adsorption composite particles includes the following steps, calculated in parts by mass: S1: 4 parts of succinic anhydride, 3 parts of 3-aminopropyltriethoxysilane, 1 part of manganese dioxide and 1.2 parts of nickel oxide are mixed and added to 100 parts of DMF solution, and heated and stirred at a water bath temperature of 45°C for 4 hours; S2: 2wt% of zinc nitrate in the S1 solution is then added, the temperature is lowered to room temperature of 25°C, and the mixture is mixed and stirred until it is completely dissolved to obtain a mixed solution; S3: 50 parts of DMF solution containing 2-methylimidazole (the mass ratio of 2-methylimidazole to zinc nitrate is 2.5:1) is added dropwise to the above-mentioned mixed solution, the temperature is raised to 65°C, and the mixture is kept warm for 7.5 hours at a stirring speed of 100 r / min, during which the pH is maintained at 6.5, thereby obtaining modified adsorption composite particles.

[0074] The average particle size of manganese dioxide and nickel oxide was 0.1 μm.

[0075] The impurity remover is lime; the mass ratio of the first filtrate to the impurity remover is 1:0.09.

[0076] Example 3

[0077] The first aspect of Example 3 provides a method for selective lithium extraction for lithium battery recovery, which includes the following steps: S1: disassembly and screening: discharging, disassembling, and classifying the lithium battery to obtain mixed waste of positive and negative electrodes; S2: acidification: adding inorganic acid to the mixed waste of positive and negative electrodes while stirring, and removing the remaining inorganic acid after the soaking is completed, and chopping and sieving the mixed waste of positive and negative electrodes; S3: heat preservation and aging: heating the mixed waste after sieving, and heat preservation and aging for 28 hours; S4: sintering and lithium leaching: roasting the mixed waste after aging Sintering. After the sintering is completed, the sintered material is cooled to room temperature and then added to a dilute sulfuric acid aqueous solution to leach the lithium sulfate solution and precipitate the leaching residue, and the leaching is cycled for 4 times; S5: impurity removal and filtration: modified adsorption composite particles are added to the lithium sulfate solution, stirred at 300 rpm for 12 hours, and then filtered through 0.1 μm microfiltration to obtain a first filtrate, an impurity remover is added to the first filtrate, and after the impurity removal is completed, a second 0.1 μm microfiltration is performed to obtain a second filtrate; S6: pH adjustment: the pH of the second filtrate is adjusted to 6.5 to obtain a lithium sulfate recovery solution.

[0078] In the mixed waste of positive and negative electrodes, the lithium content is 6.33%, the Ni content is 22.67%, the Co content is 5.85%, and the Mn content is 17.17%, calculated by mass percentage.

[0079] The inorganic acid is dilute sulfuric acid, and the concentration of the dilute sulfuric acid is 30 wt %.

[0080] The mass ratio of the inorganic acid to the mixed waste of the positive and negative electrodes is 1.2:1.

[0081] The mixed waste of positive and negative electrodes is chopped and sieved with a mesh size of 1400 meshes.

[0082] The temperature for thermal insulation and aging is 55°C.

[0083] The calcination temperature is 700°C and the calcination time is 110 min.

[0084] The mass ratio of the sintering material to the dilute sulfuric acid aqueous solution in S4 is 1:7.

[0085] The leaching rate of lithium sulfate in S4 was 99.1%.

[0086] The mass concentration of the dilute sulfuric acid aqueous solution is 10%.

[0087] The mass ratio of lithium sulfate solution to modified adsorption composite particles is 1:0.04.

[0088] The preparation method of modified adsorption composite particles includes the following steps, calculated in parts by mass: S1: 4 parts of succinic anhydride, 3 parts of 3-aminopropyltriethoxysilane, 1 part of manganese dioxide and 1.2 parts of nickel oxide are mixed and added to 100 parts of DMF solution, and heated and stirred at a water bath temperature of 45°C for 4 hours; S2: 2wt% of zinc nitrate in the S1 solution is then added, the temperature is lowered to room temperature of 25°C, and the mixture is mixed and stirred until it is completely dissolved to obtain a mixed solution; S3: 50 parts of DMF solution containing 2-methylimidazole (the mass ratio of 2-methylimidazole to zinc nitrate is 2.5:1) is added dropwise to the above-mentioned mixed solution, the temperature is raised to 65°C, and the mixture is kept warm for 7.5 hours at a stirring speed of 100 r / min, during which the pH is maintained at 6.5, thereby obtaining modified adsorption composite particles.

[0089] The average particle size of manganese dioxide and nickel oxide was 0.12 μm.

[0090] The impurity remover is lime; the mass ratio of the first filtrate to the impurity remover is 1:0.08.

[0091] Comparative Example 1

[0092] The specific implementation of this comparative example is basically the same as that of Example 1, except that: the preparation method of the modified adsorption composite particles includes the following steps, in parts by mass: S1: 4 parts of succinic anhydride, 3 parts of 3-aminopropyltriethoxysilane, 0.2 parts of manganese dioxide and 2 parts of nickel oxide are mixed and added to 100 parts of DMF solution, and heated and stirred at a water bath temperature of 45°C for 4 hours; S2: 2wt% of zinc nitrate in the S1 solution is then added, the mixture is cooled to room temperature of 25°C, mixed and stirred to dissolve completely to obtain a mixed solution; S3: 50 parts of DMF solution containing 2-methylimidazole (the mass ratio of 2-methylimidazole to zinc nitrate is 2.5:1) are added dropwise to the above-mentioned mixed solution, the temperature is raised to 65°C, and the reaction is kept warm at a stirring speed of 100 r / min for 7.5 hours, during which the pH is ensured to be 6.5.

[0093] Comparative Example 2

[0094] The specific implementation of this comparative example is basically the same as that of Example 1, except that: the preparation method of the modified adsorption composite particles includes the following steps, in parts by mass: S1: 4 parts of succinic anhydride, 3 parts of 3-aminopropyltriethoxysilane, 2 parts of manganese dioxide and 0.2 parts of nickel oxide are mixed and added to 100 parts of DMF solution, and heated and stirred at a water bath temperature of 45°C for 4 hours; S2: 2wt% of zinc nitrate in the S1 solution is then added, the mixture is cooled to room temperature of 25°C, mixed and stirred to dissolve completely to obtain a mixed solution; S3: 50 parts of DMF solution containing 2-methylimidazole (the mass ratio of 2-methylimidazole to zinc nitrate is 2.5:1) are added dropwise to the above-mentioned mixed solution, the temperature is raised to 65°C, and the reaction is kept warm at a stirring speed of 100 r / min for 7.5 hours, during which the pH is maintained at 6.5.

[0095] Comparative Example 3

[0096] The specific implementation of this comparative example is basically the same as that of Example 1, except that: the preparation method of the modified adsorption composite particles includes the following steps, in parts by mass: S1: 2 parts of succinic anhydride, 1 part of 3-aminopropyltriethoxysilane, 1 part of manganese dioxide and 1.2 parts of nickel oxide are mixed and added to 100 parts of DMF solution, and heated and stirred at a water bath temperature of 45°C for 4 hours; S2: 2wt% of zinc nitrate in the S1 solution is then added, the mixture is cooled to room temperature of 25°C, mixed and stirred to dissolve completely to obtain a mixed solution; S3: 50 parts of DMF solution containing 2-methylimidazole (the mass ratio of 2-methylimidazole to zinc nitrate is 2.5:1) are added dropwise to the above-mentioned mixed solution, the temperature is raised to 65°C, and the reaction is kept warm at a stirring speed of 100 r / min for 7.5 hours, during which the pH is maintained at 6.5.

[0097] Comparative Example 4

[0098] The specific implementation method of this comparative example is basically the same as that of Example 1, except that: the preparation method of the modified adsorption composite particles includes the following steps, in parts by mass: S1: 3 parts of succinic anhydride, 1.5 parts of 3-aminopropyltriethoxysilane, 1 part of manganese dioxide and 1.2 parts of nickel oxide are mixed and added to 100 parts of DMF solution, and heated and stirred at a water bath temperature of 45°C for 4 hours; S2: 0.5wt% of zinc nitrate in the S1 solution is then added, and the mixture is cooled to room temperature of 25°C and mixed and stirred to dissolve completely to obtain a mixed solution; S3: 50 parts of DMF solution containing 2-methylimidazole (the mass ratio of 2-methylimidazole to zinc nitrate is 3:1) are added dropwise to the above-mentioned mixed solution, the temperature is raised to 65°C, and the reaction is kept warm for 7.5 hours at a stirring speed of 100r / min, during which the pH is ensured to be 6.5.

[0099] Performance evaluation

[0100] Impurity content of lithium sulfate recovery solution: The lithium sulfate recovery solution finally obtained in the embodiment and the comparative example was tested for impurities to obtain the impurity content in the final solution. The measured values ​​were averaged over 10 tests and recorded in Table 1.

[0101] Lithium sulfate recovery rate: The recovery rates of lithium sulfate obtained in the embodiments and comparative examples were recorded, and the average values ​​of 10 tests were taken and recorded in Table 1.

[0102] Table 1

[0103] According to the examples and comparative examples and the data in Table 1, it can be seen that by adopting the specifically defined technical solution in Examples 1-3 of the present application, the efficiency and final yield of lithium extraction can be greatly improved while achieving excellent selective impurity removal, and thus have very excellent market prospects. However, since Comparative Examples 1-4 do not adopt the specifically defined technical solution, the impurity content and yield of the lithium sulfate solution produced therefrom are significantly lower than those of Examples 1-3, which strongly proves that the technical effect of the technical solution adopted in this application is not an obvious technical effect.

Claims

1. A method for selectively extracting lithium from lithium batteries, characterized in that: The steps include the following: S1: Disassembly and screening: discharge, disassemble, and classify the lithium batteries to obtain mixed waste materials of positive and negative electrodes; S2: Acidification: soak the mixed waste materials of positive and negative electrodes in inorganic acid while stirring. After soaking, remove the remaining inorganic acid and chop and sieve the mixed waste materials of positive and negative electrodes; S3: Insulation and aging: heat the sieved mixed waste materials and insulate and age them for 20-30 hours; S4: Sintering and lithium leaching: After aging, the mixed waste is roasted and sintered. After sintering, the sintered material is cooled to room temperature and added to a dilute sulfuric acid aqueous solution to leach lithium sulfate solution and precipitate leaching residue; S5: impurity removal and filtration: adding the modified adsorption composite particles to the lithium sulfate solution, stirring at 200-400 rpm for 10-20 hours, filtering out a first filtrate, adding an impurity remover to the first filtrate, and filtering out a second filtrate after impurity removal; S6: pH adjustment: adjusting the pH of the second filtrate to 6-7 to obtain a lithium sulfate recovery solution; The mixed waste of the positive and negative electrodes has a lithium content of 4-8%, a Ni content of 15-30%, a Co content of 3-8%, and a Mn content of 12-20% by mass; The inorganic acid is any one of dilute sulfuric acid, dilute hydrochloric acid, and dilute nitric acid; The mass ratio of the inorganic acid to the mixed waste of the positive and negative electrodes is (0.6-1.2):1; Preparation method of the modified adsorption composite particles The following steps are involved: S1: Add succinic anhydride, 3-aminopropyltriethoxysilane, manganese dioxide and nickel oxide to a DMF solution, and heat and stir at a water bath temperature of 40-45°C for 3-4 hours; S2: Then add zinc nitrate, cool to room temperature, mix and stir until completely dissolved to obtain a mixed solution; S3: Add the DMF solution containing imidazole dropwise to the above mixed solution, raise the temperature to 60-65°C, and keep the reaction at a stirring speed of 60-120 r / min for 5-8 hours, during which the pH is maintained at 6-7, to obtain modified adsorption composite particles.

2. The method for selectively extracting lithium from lithium battery recovery according to claim 1, wherein: The mixed waste of the positive and negative electrodes is chopped and sieved with a mesh size of 800-2000 meshes.

3. The method for selectively extracting lithium from lithium battery recovery according to claim 2, wherein: The temperature of the thermal insulation aging is 50-60°C.

4. The method for selectively extracting lithium from lithium battery recovery according to claim 3, wherein: The calcination temperature is 500-800°C.

5. The method for selectively extracting lithium from lithium battery recovery according to claim 4, characterized in that: The calcination time is 50-160 minutes.

6. The method for selectively extracting lithium from lithium battery recovery according to claim 5, characterized in that: The mass ratio of the sintering material to the dilute sulfuric acid aqueous solution in S4 is (1-1.5):(5-8).

7. The method for selective lithium extraction for lithium battery recovery according to claim 6, characterized in that: The mass ratio of the lithium sulfate solution to the modified adsorption composite particles is 1:(0.01-0.1).

8. The method for selectively extracting lithium from lithium battery recovery according to claim 7, wherein: The mass ratio of the succinic anhydride, 3-aminopropyltriethoxysilane, manganese dioxide and nickel oxide is (4-5): (2-4): (0.5-2): (0.5-2).

9. An application of the method for selective lithium extraction for lithium battery recovery according to any one of claims 1 to 8, characterized in that: This includes the application of the method for selective lithium extraction for lithium battery recovery in the lithium battery recycling and reuse process.

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