Ternary positive electrode recycled powder and preparation method thereof
The method effectively separates conductive carbon from waste ternary battery materials using flocculation and microbubble flotation, resulting in high-purity recovery powder for efficient regeneration.
Patent Information
- Application Number
- CN202411226105.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-03
- Publication Date
- 2024-12-13
AI Technical Summary
Existing methods for recycling lithium-ion battery materials are time-consuming, environmentally polluting, and result in low-purity positive electrode materials due to the difficulty in separating conductive carbon materials, which affects the regeneration process.
A method involving roasting, crushing, ultrasonic treatment, flocculation, and microbubble flotation to separate conductive carbon from waste ternary battery positive electrode powder, using polyacrylamide as a flocculant and microbubbles to enhance separation efficiency.
The method achieves a ternary positive electrode recovery powder with low carbon content and high purity, facilitating direct lithium replenishment and regeneration with improved economic benefits.
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Figure CN119133671A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of battery recycling, and in particular to a ternary positive electrode recycling powder and a preparation method thereof. Background Art
[0002] With the rapid development of the new energy industry, the market share of electric vehicles has surpassed that of traditional fuel vehicles. However, the service life of lithium batteries in electric vehicles is usually around 8-10 years, after which the lithium batteries are retired and recycled.
[0003] At present, the market uses methods such as hydrometallurgy, pyrometallurgy, and bioleaching to recover metal elements from waste lithium-ion batteries, and converts the recovered metal elements into metal compounds as raw materials to continue to produce new lithium battery materials. This method is time-consuming, environmentally polluting, and has poor economic benefits. Many studies have separated the recovered positive and negative active materials (battery black powder) from waste positive electrode materials by flotation, and directly repaired the waste positive electrode materials with lithium supplementation to turn them into regenerated positive electrode materials. However, waste positive electrode materials often carry conductive carbon materials with fine particle sizes, and simple flotation separation is difficult to effectively remove impurity conductive carbon materials, resulting in low purity of the separated waste positive electrode materials, which affects subsequent repair and regeneration.
[0004] In view of this, the present invention is proposed. Summary of the invention
[0005] The purpose of the present invention is to provide a ternary positive electrode recycling powder and a preparation method thereof. The first aspect is to provide a ternary positive electrode recycling powder with a low carbon content; the second aspect is to provide a preparation method to separate the waste positive electrode material and the conductive carbon material in the waste ternary battery positive electrode powder.
[0006] The present invention is achieved in that:
[0007] In a first aspect, the present invention provides a ternary positive electrode recycled powder, wherein the carbon content of the ternary positive electrode recycled powder is less than 0.25wt%.
[0008] In a second aspect, the present invention provides a method for preparing a ternary positive electrode recovery powder, which comprises the following steps:
[0009] S1, roasting and crushing the waste ternary battery positive electrode powder to obtain crushed material;
[0010] S2, the crushed material and water are mixed and ultrasonically treated, and further diluted with water to obtain a first slurry;
[0011] S3, mixing the first slurry with a flocculant, a collector, and a foaming agent to obtain a second slurry;
[0012] S4, performing microbubble flotation separation on the second slurry to obtain a flotation product and a flotation underflow;
[0013] S5. The flotation underflow is filtered and dried to obtain ternary positive electrode recovery powder.
[0014] In an optional embodiment, the calcination in step S1 refers to sintering at 250° C.-450° C. in an air atmosphere for 2 h-5 h.
[0015] In an optional embodiment, the solid-liquid ratio of the crushed material to water in the mixing of step S1 is 1 g: 5 mL-10 mL, and the ultrasonic time is 15 min-60 min.
[0016] In an optional embodiment, the solid content of the first slurry in step S2 is 5wt%-15wt%.
[0017] In an optional embodiment, the flocculant in step S3 is polyacrylamide.
[0018] In an optional embodiment, the mass ratio of the flocculant in step S3 to the first slurry is (100-500) g / 1 t.
[0019] In an optional embodiment, the collector in step S3 includes at least one of n-dodecane, kerosene and diesel;
[0020] or / and, the foaming agent comprises at least one of methyl isobutyl carbinol, pine oil, sec-octanol and terpene alcohol;
[0021] Or / and, the mass ratio of the collector to the first slurry is (200-500) g / 1 t;
[0022] Or / and, the mass ratio of the foaming agent to the first slurry is (150-350) g / 1t.
[0023] In an optional embodiment, the microbubble flotation separation in step S4 is performed using a microbubble-flotation column, comprising the following steps: conveying the second slurry to the microbubble-flotation column for flotation separation using a process of one roughing and two scavenging selections.
[0024] In an optional embodiment, the aeration volume of the microbubble flotation separation is 0.8 m 3 / min-3m 3 / min.
[0025] The present invention has the following beneficial effects:
[0026] The present invention uses flocculation-microbubble flotation to separate the waste ternary battery positive electrode powder to obtain ternary positive electrode recovery powder with low carbon content and high purity. A small amount of flocculant polyacrylamide is added to agglomerate small particles of conductive carbon material to increase its apparent particle size, making it easy to be captured by the collector; based on the difference in specific gravity and wettability between the conductive carbon material and the positive electrode material, the countercurrent microbubbles blown into the microbubble-flotation column are fully contacted and collided with the conductive carbon material, driving the hydrophobic conductive carbon material to float, so that the conductive carbon material is separated from the waste ternary battery positive electrode powder.
[0027] The ternary positive electrode recovery powder obtained by this method is conducive to the direct lithium replenishment and repair of the ternary positive electrode recovery powder in the later stage to prepare regenerated ternary positive electrode materials, which has huge economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.
[0029] Figure 1 This is a flow chart of a method for preparing ternary positive electrode recovery powder according to an embodiment of the present invention;
[0030] Figure 2 This is a process flow chart of microbubble flotation separation according to an embodiment of the present invention;
[0031] Figure 3 This is a scanning electron microscope image of the material of Example 1 of the present invention, wherein (a) is the positive electrode powder of the waste ternary battery, and (b) is the recycled ternary positive electrode powder. DETAILED DESCRIPTION
[0032] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.
[0033] The following is a detailed description of a ternary positive electrode recovery powder and a preparation method thereof provided by the present invention.
[0034] The present invention provides a ternary positive electrode recovery powder and a preparation method thereof, comprising the following steps:
[0035] S1, roasting and crushing the waste ternary battery positive electrode powder to obtain crushed material;
[0036] S2, the crushed material and water are mixed and ultrasonicated, and further diluted with water to obtain a first slurry;
[0037] S3, mixing the first slurry with a flocculant, a collector, and a foaming agent to obtain a second slurry;
[0038] S4, performing microbubble flotation separation on the second slurry to obtain a flotation product and a flotation underflow;
[0039] S5. The flotation underflow is filtered and dried to obtain ternary positive electrode recovery powder.
[0040] Specifically, the present invention will explain each of the above steps one by one.
[0041] In some embodiments, the waste ternary battery positive electrode powder is first low-temperature dried before roasting in step S1, and the temperature of the low-temperature drying is 100° C. to 140° C. The electrolyte of the waste ternary battery positive electrode powder is first low-temperature dried, and then pyrolyzed in an air atmosphere to remove part of the conductive carbon and binder in the waste ternary battery positive electrode powder, thereby improving the carbon removal efficiency without affecting the structure of the waste positive electrode material.
[0042] In some embodiments, the calcination in step S1 is carried out in an air atmosphere at 250°C-450°C for 2h-5h; the calcination temperature is preferably 350°C, and the calcination time is preferably 3h. A calcination temperature that is too low will lead to insufficient pyrolysis, thereby affecting the subsequent carbon removal efficiency; a calcination temperature that is too high will destroy the structure of the waste positive electrode material, which is not conducive to the subsequent repair and regeneration.
[0043] In some embodiments, the pulverization in step S1 is performed by a jet mill, and the residual carbon impurities in the pulverized material are separated from the pulverized material by the jet mill.
[0044] In some embodiments, the solid-to-liquid ratio of the crushed material to water in the mixing in step S2 is 1 g:5 mL-10 mL, preferably 1 g:5 mL.
[0045] In some embodiments, the ultrasound time in step S2 is 15 min-60 min.
[0046] In some embodiments, in step S2, the solid content of the first slurry is 5 wt%-15 wt%.
[0047] In some embodiments, the flocculant in step S3 includes polyacrylamide, preferably at least one of anionic polyacrylamide and / or cationic polyacrylamide; the mass ratio of the flocculant to the first slurry is (100-500) g / 1t, preferably 300 g / 1t.
[0048] Flocculant polyacrylamide relies on adsorption and bridging to preferentially aggregate small particles of conductive carbon materials, increase their apparent particle size to obtain aggregates, and make them easier to capture. The quality of the flocculant will affect the separation efficiency. If the quality of the flocculant is too low, it will not be able to effectively aggregate all the fine conductive carbon materials; if the quality of the flocculant is too high, the hydrophobicity of the aggregates will be weakened, and it is easy to carry waste positive electrode materials, making it difficult to capture and the separation efficiency is low.
[0049] In some embodiments, the collector in step S3 includes at least one of n-dodecane, kerosene and diesel; or / and, the mass ratio of the collector to the first slurry is (200-500) g / 1t, preferably 400 g / 1t.
[0050] In some embodiments, the foaming agent in step S3 includes at least one of methyl isobutyl carbinol, pine oil, octanol and terpene alcohol; or / and, the mass ratio of the foaming agent to the first slurry is (150-350) g / 1t, preferably 300 g / 1t, and the foaming agent is preferably methyl isobutyl carbinol and pine oil added simultaneously.
[0051] In some embodiments, the microbubble flotation separation in step S4 is performed using a microbubble-flotation column operation: the second slurry is transported to the microbubble-flotation column, and flotation separation is performed using a process of one roughing and two scavenging selections to obtain a flotation product and a flotation underflow.
[0052] The microbubble-flotation column uses gravity sinking and bubble rise to achieve the flotation of fine-grained materials. A large number of micro-nano bubbles are injected from the bottom to flow upstream and fully contact and collide with the slurry, so that the micro-nano bubbles contact the conductive carbon material, and the conductive carbon material rises to the top of the column with the bubbles to form a foam layer (flotation product). As mentioned above, a small amount of flocculant polyacrylamide agglomerates the conductive carbon material to increase its apparent particle size, and the micro-nano bubbles contact more conductive carbon material faster.
[0053] In some embodiments, the aeration volume of the microbubble flotation in step S4 is 0.8 m 3 / min-3m 3 / min.
[0054] In some embodiments, the flotation underflow in step S5 is filtered and dried at 100° C.-130° C. to obtain the ternary positive electrode recovery powder. The flotation product is also filtered and dried to obtain carbonaceous aggregates.
[0055] In some embodiments, the process further includes supplementing lithium by solid phase sintering the ternary positive electrode recovery powder and a lithium source to obtain a regenerated ternary positive electrode active material.
[0056] In some embodiments, the process further includes acid leaching, impurity removal and separation of the carbonaceous aggregates to recover the waste positive electrode materials entrained in the carbonaceous aggregates.
[0057] The features and performance of the present invention are further described in detail below in conjunction with the accompanying drawings, examples and comparative examples. It should be understood that these examples are only used to illustrate the present application and are not used to limit the scope of the present application.
[0058] All experimental materials in the present invention are the positive electrode sheets obtained by disassembling retired ternary lithium batteries. After crushing, separation, sieving and low-temperature drying, the waste ternary battery positive electrode powder is obtained. The carbon content in the waste ternary battery positive electrode powder is 2.6880% after testing.
[0059] Example 1
[0060] This embodiment provides a ternary positive electrode recycling powder and a preparation method thereof, comprising:
[0061] S1. Calcination and crushing: The positive electrode powder of the waste ternary battery is calcined in an air atmosphere at 350°C for 3 hours, and then crushed in a jet mill to obtain a crushed material.
[0062] S2. Ultrasonic dilution: the crushed material and water are mixed at a solid-liquid ratio of 1 g:5 mL and ultrasonically treated for 30 min, and further diluted with water to obtain a first slurry with a solid content of 10 wt%.
[0063] S3, adding 300 g of anionic polyacrylamide with a molecular weight of 12 million, 400 g of kerosene, 100 g of methyl isobutyl carbinol and 200 g of pine oil per ton of the first slurry, mixing and stirring to obtain a second slurry.
[0064] S4. Microbubble flotation: The second slurry is fed into the microbubble-flotation column. A large number of fine bubbles are injected into the bottom of the microbubble-flotation column to flow upstream, and a roughing selection and two scavenging selections are performed to obtain the flotation product and the flotation underflow.
[0065] Among them, the air volume for roughing and sweeping is 1.2m 3 / min.
[0066] S5. After flotation underflow filtration and drying, ternary positive electrode recovery powder is obtained; flotation product filtration and drying are performed to obtain carbonaceous aggregates.
[0067] The ternary positive electrode recovery powder and lithium source are supplemented with lithium through solid phase sintering to obtain regenerated ternary positive electrode active material; the carbon-containing aggregates are acid-leached, impurity-removed and separated to recover the waste positive electrode materials entrained in the carbon-containing aggregates.
[0068] The preparation method of the ternary positive electrode recovery powder of this embodiment is as shown in the attached Figure 1 shown.
[0069] The process flow of microbubble flotation in this embodiment is shown in the attached figure. Figure 2 As shown, microbubble flotation includes one roughing and two scavenging. After the roughing flotation separation, the bottom underflow enters the next flotation column to continue adding flocculants, collectors and frothers, and two scavengings are performed to obtain the flotation underflow. Each time the upper foam is collected to obtain the flotation product.
[0070] The material scanning electron microscope image of this embodiment is shown in the attached Figure 3 As shown in the figure, (a) is the cathode powder of the used ternary battery, and (b) is the recovered cathode powder of the ternary battery. The surface of the cathode powder of the used ternary battery is covered with a large amount of fine conductive carbon materials. After a series of separation operations, the surface of the recovered cathode powder of the ternary battery is clean.
[0071] Example 2
[0072] This embodiment provides a ternary positive electrode recycling powder and a preparation method thereof, comprising:
[0073] S1. The positive electrode powder of the waste ternary battery is calcined in an air atmosphere at 250° C. for 5 h, and then crushed in a jet mill to obtain a crushed material.
[0074] S2. The crushed material and water were mixed at a solid-liquid ratio of 1 g:5 mL and ultrasonicated for 60 min, and then further diluted with water to obtain a first slurry with a solid content of 15 wt%.
[0075] S3. Add 500 g of anionic polyacrylamide with a molecular weight of 12 million, 500 g of kerosene, 150 g of methyl isobutyl carbinol and 200 g of pine oil per ton of the first slurry, mix and stir to obtain a second slurry.
[0076] S4, feeding the second slurry into the microbubble-flotation column, injecting a large number of fine bubbles at the bottom of the microbubble-flotation column to flow upstream, performing one roughing selection and two scavenging selections to obtain the flotation product and the flotation underflow.
[0077] Among them, the air volume for roughing and sweeping is 0.8m 3 / min.
[0078] S5. After flotation underflow filtration and drying, ternary positive electrode recovery powder is obtained; flotation product filtration and drying are performed to obtain carbonaceous aggregates.
[0079] The ternary positive electrode recovery powder and lithium source are supplemented with lithium through solid phase sintering to obtain regenerated ternary positive electrode active material; the carbon-containing aggregates are acid-leached, impurity-removed and separated to recover the waste positive electrode materials entrained in the carbon-containing aggregates.
[0080] Example 3
[0081] This embodiment provides a ternary positive electrode recycling powder and a preparation method thereof, comprising:
[0082] S1. The positive electrode powder of the waste ternary battery is calcined in an air atmosphere at 450° C. for 2 h, and then crushed in a jet mill to obtain a crushed material.
[0083] S2. The crushed material and water were mixed at a solid-liquid ratio of 1 g:10 mL and ultrasonicated for 15 min, and further diluted with water to obtain a first slurry with a solid content of 5 wt%.
[0084] S3. Add 100 g of anionic polyacrylamide with a molecular weight of 12 million, 200 g of diesel, 50 g of methyl isobutyl carbinol and 100 g of pine oil to each ton of the first slurry, mix and stir to obtain a second slurry.
[0085] S4. The second slurry is fed into the microbubble-flotation column. A large number of fine bubbles are injected into the bottom of the microbubble-flotation column to flow upstream, and a roughing selection and two scavenging selections are performed to obtain the flotation product and the flotation underflow.
[0086] Among them, the air volume for roughing and sweeping is 3m 3 / min.
[0087] S5. After flotation underflow filtration and drying, ternary positive electrode recovery powder is obtained; flotation product filtration and drying are performed to obtain carbonaceous aggregates.
[0088] The ternary positive electrode recovery powder and lithium source are supplemented with lithium through solid phase sintering to obtain regenerated ternary positive electrode active material; the carbonaceous aggregates are acid-leached, impurity-removed and separated to recover the waste positive electrode materials entrained in the carbonaceous aggregates.
[0089] Example 4
[0090] This embodiment provides a ternary positive electrode recycling powder and a preparation method thereof, which is basically the same as that of Embodiment 1, except that in step S1, the calcination temperature is 280°C.
[0091] Example 5
[0092] This embodiment provides a ternary positive electrode recycling powder and a preparation method thereof, which is basically the same as that of Embodiment 1, except that in step S1, the calcination temperature is 420°C.
[0093] Example 6
[0094] This embodiment provides a ternary positive electrode recovery powder and a preparation method thereof, which is basically the same as Example 1, except that in step S3, 150 g of anionic polyacrylamide with a molecular weight of 12 million is added to each ton of the first slurry.
[0095] Example 7
[0096] This embodiment provides a ternary positive electrode recovery powder and a preparation method thereof, which is basically the same as Example 1, except that in step S3, 450 g of anionic polyacrylamide with a molecular weight of 12 million is added to each ton of the first slurry.
[0097] Comparative Example 1
[0098] This embodiment provides a ternary positive electrode recovery powder and a preparation method thereof, which is basically the same as that of Embodiment 1, except that the flocculant anionic polyacrylamide is not added in step S3.
[0099] Comparative Example 2
[0100] This embodiment provides a ternary positive electrode recovery powder and a preparation method thereof, which is basically the same as that of Embodiment 1, except that a conventional flotation equipment mechanical stirring flotation machine is used for flotation in step S4.
[0101] Comparative Example 3
[0102] This embodiment provides a ternary positive electrode recovery powder and a preparation method thereof, which is basically the same as Example 1, except that no flocculant anionic polyacrylamide is added in step S3, and a conventional flotation equipment mechanical stirring flotation machine is used for flotation in step S4.
[0103] Comparative Example 4
[0104] This embodiment provides a ternary positive electrode recovery powder and a preparation method thereof, which is basically the same as Example 1, except that in step S3, 800 g of anionic polyacrylamide with a molecular weight of 12 million is added to each ton of the first slurry.
[0105] Test Example 1: Carbon content test
[0106] The sample was placed in a sulfur-carbon tester to test its carbon content. The test results are shown in Table 1.
[0107] Test Example 2: Carbon Recovery Rate Calculation
[0108] The carbon recovery rate was calculated by the following formula.
[0109]
[0110] Among them, α1 is the yield of carbon-containing aggregates, β1 is the carbon content of carbon-containing aggregates, α2 is the yield of ternary positive electrode recycled powder, and β2 is the carbon content of ternary positive electrode recycled powder.
[0111] Table 1
[0112]
[0113]
[0114] As shown in Table 1, the embodiments and comparative examples 1-4, the carbon content in the ternary positive electrode recovery powder in the embodiments is less than 0.25wt%, and the conductive carbon material of the waste ternary battery positive electrode powder is efficiently removed by adding a small amount of flocculant polyacrylamide and microbubble flotation separation. Too much conductive carbon material attached to the surface of the ternary positive electrode recovery powder will affect the subsequent regeneration effect of the molten salt method, and the electrical properties of the synthesized regenerated ternary positive electrode active material are difficult to meet the standards.
[0115] It can be seen from Table 1, Examples 1, 6-7 and Comparative Example 4 that the quality of the flocculant polyacrylamide used can affect the separation effect. If the flocculant quality is too low, the carbon removal effect is poor; if the flocculant quality is too large and exceeds the range, the loss of the ternary positive electrode recovered powder is too much.
[0116] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.
Claims
1. A ternary cathode recycling powder, It is characterized in that The carbon content of the ternary positive electrode recycled powder is less than 0.25wt%.
2. A method for preparing the ternary positive electrode recycling powder according to claim 1, It is characterized in that The following steps are involved: S1, roasting and crushing the waste ternary battery positive electrode powder to obtain crushed material; S2, the crushed material and water are mixed and ultrasonicated, and further diluted with water to obtain a first slurry; S3, mixing the first slurry with a flocculant, a collector, and a foaming agent to obtain a second slurry; S4, performing microbubble flotation separation on the second slurry to obtain a flotation product and a flotation underflow; S5. The flotation underflow is filtered and dried to obtain ternary positive electrode recovery powder.
3. The method for preparing the ternary positive electrode recovery powder according to claim 2, It is characterized in that The calcination refers to sintering at 250°C-450°C in air atmosphere for 2h-5h 。 4. The method for preparing the ternary positive electrode recovery powder according to claim 2, It is characterized in that The solid-liquid ratio of the crushed material to water in the mixing is 1g:5mL-10mL, and the ultrasonic time is 15min-60min.
5. The method for preparing the ternary positive electrode recycling powder according to claim 2, It is characterized in that The solid content of the first slurry is 5wt%-15wt%.
6. The method for preparing the ternary positive electrode recovery powder according to claim 2, It is characterized in that The flocculant is polyacrylamide.
7. The method for preparing the ternary positive electrode recovery powder according to claim 2, It is characterized in that The mass ratio of the flocculant to the first slurry is (100-500) g / 1 t.
8. The method for preparing the ternary positive electrode recovery powder according to claim 2, It is characterized in that The collector comprises at least one of n-dodecane, kerosene and diesel; or / and, the foaming agent comprises at least one of methyl isobutyl carbinol, pine oil, sec-octanol and terpene alcohol; Or / and, the mass ratio of the collector to the first slurry is (200-500) g / 1 t; Or / and, the mass ratio of the foaming agent to the mass ratio of the first slurry is (150-350) g / 1t 。 9. The method for preparing the ternary positive electrode recycling powder according to claim 2, It is characterized in that The microbubble flotation separation adopts a microbubble-flotation column operation, and includes the following steps: conveying the second slurry to the microbubble-flotation column, and performing flotation separation by adopting a process of primary roughing and secondary scavenging.
10. The method for preparing the ternary positive electrode recycling powder according to claim 2 or 9, It is characterized in that The aeration volume of the microbubble flotation separation is 0.8m 3 / min-3m 3 / min.