Flotation separation method and device for waste lithium battery electrode material
Through the grinding-jet-flotation process, the problem of low separation efficiency of waste lithium battery electrode materials is solved, and efficient separation of graphite and lithium cobalt oxide and low drug consumption are achieved, with significant economic benefits.
Patent Information
- Application Number
- CN202510741907.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-05
- Publication Date
- 2025-08-19
AI Technical Summary
In the prior art, the separation efficiency of waste lithium battery electrode materials is low, especially the separation of graphite and lithium cobalt oxide is difficult, and the drug consumption is large, resulting in low recycling efficiency.
The grinding-jet-flotation process is adopted to remove polyvinylidene fluoride by grinding, increase the hydrophobic difference between graphite and lithium cobalt oxide particles, and promote microbubble nucleation with cationic surfactant and air supersaturated water, and improve separation efficiency with jet treatment.
It achieves efficient separation of graphite and lithium cobalt oxide, reduces drug consumption, simple process, less investment, and significant economic benefits.
Smart Images
Figure CN120502436A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of recycling and separation of waste lithium battery electrode materials, and in particular to a flotation separation method and device for waste lithium battery electrode materials. Background Art
[0002] With the continuous growth in sales of mobile phones, computers, electric bicycles, and new energy vehicles, the use of lithium-ion batteries is increasing. In actual use, the lifespan of lithium-ion batteries used in mobile phones and computers is generally 2 to 3 years, the lifespan of lithium-ion batteries used in new energy vehicles is about 5-8 years, and the lifespan of lithium-ion batteries used in electric bicycles is somewhere in between. When a lithium-ion battery exceeds this period, its electrodes swell, the battery capacity decreases, and it becomes scrapped. In addition, with the ever-increasing pace of replacement of lithium-ion battery carriers in domestic electronic products, the lifespan of lithium-ion batteries is being artificially shortened, leading to premature scrapping. Such a huge amount of discarded lithium-ion batteries will pose a severe challenge to the environment.
[0003] Lithium-ion batteries consist of a casing, positive and negative current collectors (aluminum and copper foil), a negative active material (such as graphite), a separator, a positive active material (typically various complex lithium compounds), and an electrolyte. The electrode materials contain significant amounts of metals such as cobalt (5%-20%), nickel (5%-10%), and manganese (5%-10%), as well as a significant amount of graphite powder (14-19%). It's worth noting that metals like cobalt and nickel are scarce resources. The vast majority of cobalt ore in my country is co-produced, with a grade of only 0.03-0.294%, accounting for approximately 1.1% of the world's reserves. Therefore, recycling and reusing discarded lithium batteries is of practical significance both for environmental protection and for secondary resource utilization.
[0004] Currently, conventional beneficiation methods for recycling discarded lithium batteries treat them as high-grade, premium ore. They are first disassembled and discharged, then separated through a series of crushing, screening, airflow separation, magnetic separation, and electrostatic separation processes to separate bulk metal casings, plastics, and separators. Lithium-ion batteries exhibit selective crushing during crushing, with the metal casings and separators concentrated in the +2mm particle size range, exhibiting significant density differences and amenable to dry separation. Aluminum foil, copper foil, and some separators can be separated electrostatically after further grinding. Active materials in the positive and negative electrodes are typically smaller than 50μm and appear in the finest material, typically separated by flotation. After heat treatment, the electrode materials are separated by flotation to produce tailings with lithium and cobalt content exceeding 93%. However, due to the addition of polyvinylidene fluoride (PVDF) as a binder during lithium battery manufacturing, the adhesion of this organic matter to the particle surface reduces the hydrophobicity difference between the positive and negative electrode materials, making flotation difficult and inefficient. It is reported that if the crushed cobalt-rich ore is directly floated without any treatment measures, the cobalt grade will only increase from 24.21% to 28.08%, and the flotation effect is not obvious.
[0005] Currently, researchers have proposed various methods to remove this organic film layer, such as heat treatment, chemical oxidation, and mechanical surface stripping. Compared to heat treatment and chemical oxidation, grinding is a relatively mature technology with a higher level of industrialization and is easier to implement in existing mineral processing plants. However, since the particle size of lithium-ion battery positive and negative electrode materials is already at the level of tens of microns, grinding will inevitably further reduce the particle size distribution of the materials, reducing the efficiency of existing separation technologies and increasing chemical consumption, posing a serious challenge. Summary of the Invention
[0006] The present application provides a flotation separation method and device for waste lithium battery electrode materials, aiming to solve the technical problems of low separation efficiency of key components of existing waste lithium battery electrode materials and high chemical consumption during the separation process.
[0007] In order to achieve the above objectives, this application adopts the following technical solutions.
[0008] In a first aspect of the present application, a flotation separation method for waste lithium battery electrode materials is provided, comprising:
[0009] S1, crushing and screening the discarded lithium batteries to collect the mixed powder of electrode materials;
[0010] S2, mixing the mixed powder with water to prepare a slurry, passing the slurry through a grinding equipment for grinding pretreatment, and diluting the slurry after the grinding pretreatment with water to prepare a working slurry;
[0011] S3, adding a cationic surfactant, a non-polar oil collector, a foaming agent and air-supersaturated water into the working slurry, and stirring the mixture evenly in a slurry mixing device to obtain a primary slurry;
[0012] S4, sending the primary slurry to the jet device for jet treatment, and then stirring and slurrying in the slurry mixing equipment to obtain the secondary slurry;
[0013] S5, flotation the secondary slurry through a flotation device to separate graphite powder and positive electrode active material powder.
[0014] Preferably, the jet device includes a venturi tube, a slurry distribution cone and a plurality of porous baffles;
[0015] Wherein, the slurry distribution cone is arranged at the contraction section of the venturi tube, and the small head of the slurry distribution cone faces the inlet direction of the venturi tube;
[0016] Each porous baffle is arranged radially in the diffusion section of the venturi tube, and the multiple porous baffles are parallel to each other.
[0017] Further preferably, the shape of the porous baffle is arched, and the number of the porous baffles is 3; the flow openings of the middle porous baffle are in opposite directions to the flow openings of the arched baffles on both sides thereof.
[0018] Preferably, the mass concentration of the slurry is 30-50wt%;
[0019] Preferably, the mass concentration of the working slurry is 5 to 10 wt%.
[0020] Preferably, the cationic surfactant is dodecyltrimethylammonium bromide;
[0021] The non-polar oil collector includes kerosene, diesel or dodecane;
[0022] The foaming agent is sec-octanol or methyl isobutyl carbinol.
[0023] Preferably, the amount of the cationic surfactant in the working slurry is 10 to 50 g / t;
[0024] The amount of the non-polar oil collector in the working slurry is 200-500 g / t;
[0025] The amount of the foaming agent used in the working slurry is 100-200 g / t.
[0026] Preferably, the air supersaturated water is prepared by pressurizing at room temperature, and the pressure is 0.20 to 0.50 MPa.
[0027] Preferably, the grinding equipment is a ball mill, a rod mill or a stirred mill; the slurry mixing equipment is a stirring barrel; and the flotation equipment is a flotation machine or a flotation column.
[0028] In a second aspect of the present application, a flotation separation device for waste lithium battery electrode materials is provided, comprising:
[0029] The first stirring barrel has a discharge port connected to the feed port of the grinding equipment through a first feeding pump; the discharge port of the grinding equipment is connected to the inlet of the second stirring barrel through a pipeline; the discharge port of the second stirring barrel is connected to the inlet of the jet device through a second feeding pump; the outlet of the jet device is connected to the inlet of the third stirring barrel through a pipeline; and the outlet of the third stirring barrel is connected to the feed port of the flotation equipment through a pipeline.
[0030] Compared with the prior art, the present invention has the following advantages:
[0031] The present application combines a grinding-jet-flotation process. First, a grinding activation pretreatment is performed to remove part of the bonded polyvinylidene fluoride, exposing the original hydrophobic and hydrophilic surfaces of the graphite and lithium cobalt oxide particles, thereby increasing the hydrophobicity difference between the two particles. Then, an appropriate amount of cationic surfactant is used to create hydrophobic sites on the surface of the graphite particles, thereby promoting the nucleation and development of microbubbles on the surface of the particles in gas-supersaturated water. Finally, jet treatment is used to precipitate micro-nano bubbles on the surface of the hydrophobic graphite particles, and flotation is then used to promote the formation of graphite particle aggregates, ultimately achieving efficient recovery of graphite and lithium cobalt oxide.
[0032] This application utilizes the natural hydrophobicity of graphite, which promotes microbubble nucleation on the particle surface. Through key process design, graphite particle agglomeration is promoted, achieving the relative enrichment of graphite and lithium cobalt oxide particles. This separation method is highly adaptable to different types of discarded lithium batteries, addressing the challenges of low flotation efficiency and high reagent consumption in traditional flotation. It also features a simple process, low investment, and low operating costs, resulting in significant economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some of the embodiments described in this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.
[0034] Figure 1 This is a schematic structural diagram of the flotation separation device of this application;
[0035] The accompanying drawings are marked as follows: 1. first stirring barrel; 2. first feeding pump; 3. grinding equipment; 4. second stirring barrel; 5. second feeding pump, 6. jet device; 7. third stirring barrel; 8. flotation equipment;
[0036] Figure 2 This is a schematic structural diagram of the fluidic device of the present application;
[0037] The accompanying drawings are numerals: 61. Venturi tube; 62. Slurry distribution cone; 63. Porous baffle;
[0038] Figure 3 Schematic diagram of the structure of the porous baffle. DETAILED DESCRIPTION
[0039] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.
[0040] In the following description of this embodiment, the terms "include", "comprising", "having" and "containing" are open-ended terms, meaning including but not limited to.
[0041] In the following description of this embodiment, the term "and / or" is used to describe the association relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, B exists alone, and both A and B exist. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.
[0042] In the following description of this embodiment, the term "at least one" refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.
[0043] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.
[0044] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of serial numbers does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.
[0045] It will be understood by those skilled in the art that the numerical ranges in the examples of the present application are to be understood as specifically disclosing each intermediate value between the upper and lower limits of the range. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also included in the present application. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.
[0046] Unless otherwise indicated, the technical / scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this application belongs. Although this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of any conflict with any incorporated document, the content of this specification shall prevail.
[0047] In a first aspect of the present application, a flotation separation method for waste lithium battery electrode materials is provided, comprising:
[0048] S1, crushing and screening the discarded lithium batteries to collect the mixed powder of electrode materials;
[0049] In this application, a mixed powder of positive and negative active materials from discarded lithium batteries is collected using conventional methods. The positive active material includes lithium cobalt oxide or lithium iron phosphate powder, as well as other positive active materials commonly used in lithium batteries; the negative active material is graphite powder.
[0050] S2, mixing the mixed powder with water to prepare a slurry, passing the slurry through a grinding equipment for grinding pretreatment, and diluting the slurry after the grinding pretreatment with water to prepare a working slurry;
[0051] In this application, the mixed powder is dispersed in water to prepare a slurry with a mass concentration of 30 to 50 wt%. The slurry is then added to a grinding machine for pre-grinding treatment to remove some of the polyvinylidene fluoride adhering to the surface of the mixed powder, exposing the original hydrophobic surface of the graphite and the original hydrophilic surface of the positive active material such as lithium cobalt oxide, thereby increasing the hydrophobicity difference between the graphite particles and the lithium cobalt oxide particles. After the pre-grinding treatment, the slurry is diluted with water to a working slurry with a mass concentration of 5 to 10 wt%.
[0052] In the present application, the grinding equipment is a ball mill, a rod mill or a stirred mill.
[0053] S3, adding a cationic surfactant, a non-polar oil collector, a foaming agent and air-supersaturated water into the working slurry, and stirring the mixture evenly in a slurry mixing device to obtain a primary slurry;
[0054] In the present application, the slurry mixing equipment is a stirring barrel.
[0055] In the present application, the cationic surfactant is dodecyltrimethylammonium bromide; its usage in the working slurry is 10-50 g / t;
[0056] The non-polar oil collector includes kerosene, diesel or dodecane; the amount of the non-polar oil collector in the working slurry is 200 to 500 g / t;
[0057] The foaming agent is sec-octanol or methyl isobutyl carbinol, and its usage in the working slurry is 100-200 g / t.
[0058] The air supersaturated water is prepared by passing air with a pressure of 0.20 to 0.50 MPa into water at room temperature.
[0059] The lithium salt of the present invention and an appropriate amount of cationic surfactant create hydrophobic sites on the surface of graphite particles, and promote the nucleation and development of microbubbles on the surface of the particles in gas supersaturated water through air supersaturated water and a foaming agent; the hydrophobicity of the graphite particles is further improved by a collector.
[0060] S4, sending the primary slurry to the jet device for jet treatment, and then stirring and slurrying in the slurry mixing equipment to obtain the secondary slurry;
[0061] In the present application, the jet device includes a Venturi tube, a slurry distribution cone, and multiple porous baffles. The slurry distribution cone is disposed in the contraction section of the Venturi tube, with the small end of the slurry distribution cone facing the inlet of the Venturi tube. Each porous baffle is radially disposed in the diffusion section of the Venturi tube, and the multiple porous baffles are parallel to each other. To achieve better results, the porous baffle is arched, has multiple through-holes, and has a flow gap between the top of the porous baffle and the tube wall. The number of porous baffles is preferably three, and the flow gap of the middle porous baffle is opposite to the flow gaps of the arched baffles on both sides.
[0062] When the slurry is treated by jet, on the one hand, there is a large pressure gradient in the radial and axial directions inside the jet tube, and the hydrophobic graphite particles are easily formed with micro-nano bubbles on their surface under the action of the external pressure gradient; on the other hand, the gas dissolved in the water will accumulate into microbubbles. The presence of the baffle in the jet tube increases the turbulence of the slurry and increases the collision efficiency between graphite and bubbles. These two factors jointly promote the separation efficiency of graphite and lithium cobalt oxide.
[0063] S5, flotation the secondary slurry through a flotation device to separate graphite powder and positive electrode active material powder.
[0064] In the present application, the flotation equipment is a flotation machine or a flotation column.
[0065] In the second aspect, the present application provides a flotation separation device for waste lithium battery electrode materials, the structure of which is as follows: Figure 1 As shown, including:
[0066] The discharge port of the first mixing barrel 1 (A) is connected to the feed port of the grinding equipment 3 (C) via a first feeding pump 2 (B); the discharge port of the grinding equipment 3 (C) is connected to the inlet of the second mixing barrel 4 (D) via a pipeline; the discharge port of the second mixing barrel 4 (D) is connected to the inlet of the jet device 6 (F) via a second feeding pump 5 (E); the outlet of the jet device 6 (F) is connected to the inlet of the third mixing barrel 7 (G) via a pipeline; the outlet of the third mixing barrel 7 (G) is connected to the feed port of the flotation equipment 8 (H) via a pipeline;
[0067] Among them, Figure 2 As shown, the jet device 6 includes a venturi tube 61, a slurry distribution cone 62 and a plurality of porous baffles 63; the slurry distribution cone 62 is arranged in the contraction section of the venturi tube 61, and the small head of the slurry distribution cone 61 is facing the inlet direction of the venturi tube; each porous baffle 63 is radially arranged in the diffusion section of the venturi tube 61, and the multiple porous baffles are parallel to each other.
[0068] As a preferred solution of this application, Figure 3 As shown, the porous baffle 63 is in the shape of an arch, which has multiple through holes, and there is a flow gap between the top of the porous baffle and the tube wall; the number of porous baffles 63 is preferably 3, and the flow gap of the middle porous baffle is in the opposite direction to the flow gap of the arched baffles on both sides thereof.
[0069] The present application is further described below through examples.
[0070] like Figure 1As shown, a mixed powder of water and electrode materials is fed into the first stirring barrel 1 for mixing. After uniform mixing, the slurry is fed into the grinding equipment 3 through the first feeding pump 2 for grinding. The organic matter polyvinylidene fluoride on the surface of the particles is stripped off through moderate grinding, and the grinding time is 30s. The ground slurry is diluted to prepare a working slurry, which is fed into the second stirring barrel 4. At the same time, a non-polar oil collector, a foaming agent, a cationic surfactant and air-saturated water are added to the second stirring barrel 4 and mixed with the working slurry to obtain a primary slurry; then it is fed into the venturi tube 6 through the second feeding pump 5, and micro-nano bubbles are precipitated on the surface of the hydrophobic graphite particles at low pressure or negative pressure at the gradually widening part of its cross section. After jet treatment, the slurry is fed into the third stirring barrel 7 for secondary slurry mixing to obtain a secondary slurry; the secondary slurry flows into the flotation column 8 by gravity, and the aeration volume is 0.2m 3 / h, the flotation time is 3 minutes, and the flotation foam is collected as graphite concentrate; the flotation tailings are collected as lithium cobalt oxide.
[0071] This application conducted a total of three sets of experiments, and the process parameters for each set of experiments are shown in Table 1. At the same time, a control group was set up for each set of experiments. The difference between the control group and the experimental group was that the slurry was not subjected to jet treatment, and the slurry was directly fed into the flotation column for flotation after one slurrying. The amount of cationic surfactant used was fixed at 20 g / t, and the amount of frother used was fixed at 70 g / t. The remaining steps and process parameters were the same as those of this set of experiments.
[0072] Table 1 Process parameters of three groups of experiments
[0073]
[0074] As shown in Table 1, the flotation separation method of the present application achieves high concentrate yields, achieving relative enrichment of graphite and lithium cobalt oxide particles. At the same reagent dosage, the concentrate yields achieved using the flotation separation method of the present application are higher than those achieved using conventional flotation methods, resolving the challenges of low flotation efficiency and high reagent consumption in traditional flotation. Furthermore, the flotation separation method of the present application offers a simple process, low investment, and low operating costs, resulting in significant economic benefits.
[0075] Although this specification has been used to fully describe the present application using general descriptions and specific embodiments, it is obvious to those skilled in the art that modifications or improvements may be made based on the present application. Therefore, such modifications or improvements made without departing from the spirit of the present application are within the scope of protection claimed in this application.
Claims
1. A flotation separation method for waste lithium battery electrode materials, characterized in that: include: S1, crushing and screening the discarded lithium batteries to collect the mixed powder of electrode materials; S2, mixing the mixed powder with water to prepare a slurry, passing the slurry through a grinding equipment for grinding pretreatment, and diluting the slurry after the grinding pretreatment with water to prepare a working slurry; S3, adding a cationic surfactant, a non-polar oil collector, a foaming agent and air-supersaturated water into the working slurry, and stirring the mixture evenly in a slurry mixing device to obtain a primary slurry; S4, sending the primary slurry to the jet device for jet treatment, and then stirring and slurrying in the slurry mixing equipment to obtain the secondary slurry; S5, flotation the secondary slurry through a flotation device to separate graphite powder and positive electrode active material powder.
2. The preparation method according to claim 1, characterized in that The jet device includes a venturi tube, a slurry distribution cone and a plurality of porous baffles; Wherein, the slurry distribution cone is arranged at the contraction section of the venturi tube, and the small head of the slurry distribution cone faces the inlet direction of the venturi tube; Each porous baffle is arranged radially in the diffusion section of the venturi tube, and the multiple porous baffles are parallel to each other.
3. The preparation method according to claim 2, characterized in that The porous baffle is in an arch shape, and the number of the porous baffles is 3; the flow opening of the middle porous baffle is in the opposite direction to the flow openings of the arched baffles on both sides thereof.
4. The preparation method according to claim 1, characterized in that The mass concentration of the ore pulp is 30-50 wt%.
5. The preparation method according to claim 1, characterized in that The mass concentration of the working slurry is 5-10 wt%.
6. The preparation method according to claim 1, characterized in that The cationic surfactant is dodecyltrimethylammonium bromide; The non-polar oil collector includes kerosene, diesel or dodecane; The foaming agent is sec-octanol or methyl isobutyl carbinol.
7. The preparation method according to claim 1, characterized in that The amount of the cationic surfactant used in the working slurry is 10 to 50 g / t; The amount of the non-polar oil collector in the working slurry is 200-500 g / t; The amount of the foaming agent used in the working slurry is 100-200 g / t.
8. The preparation method according to claim 1, characterized in that The air supersaturated water is prepared by pressurizing at room temperature, and the pressure is 0.20-0.50 MPa.
9. The preparation method according to claim 1, characterized in that The grinding equipment is a ball mill, a rod mill or a stirred mill; The slurry mixing equipment is a stirring barrel; The flotation equipment is a flotation machine or a flotation column.
10. A flotation separation device for waste lithium battery electrode materials, characterized in that: include: The first stirring barrel has a discharge port connected to the feed port of the grinding equipment through a first feeding pump; the discharge port of the grinding equipment is connected to the inlet of the second stirring barrel through a pipeline; the discharge port of the second stirring barrel is connected to the inlet of the jet device through a second feeding pump; the outlet of the jet device is connected to the inlet of the third stirring barrel through a pipeline; and the outlet of the third stirring barrel is connected to the feed port of the flotation equipment through a pipeline.