Lithium iron phosphate recovery device

Abstract

The utility model provides a lithium iron phosphate recovery device, and relates to the technical field of batteries. The lithium iron phosphate recovery device comprises a crushing structure for crushing lithium iron phosphate pole pieces in waste lithium iron phosphate batteries; an inlet of the first screening part communicates with an outlet of the crushing structure; a feeding port of the grinding equipment communicates with an outlet of the first screening part, and the grinding equipment is used for grinding the primarily screened materials screened by the first screening part; an inlet of the second screening part is communicated with a discharging opening of the grinding equipment so as to screen a grinding material discharged by the grinding equipment to obtain lithium iron phosphate powder, chemical reagents are not needed, physical recovery of lithium iron phosphate is achieved, the phenomenon of environmental pollution caused by the adoption of the chemical reagents is avoided, secondary pollution cannot be caused, and the service life of the lithium iron phosphate powder is prolonged. And the subsequent treatment cost is reduced, the phenomenon that the metal foil is corroded by adopting a chemical reagent is avoided, and the recovery quality of metal is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a lithium iron phosphate recycling device. Background Technology

[0002] Lithium iron phosphate (LFP) batteries are lithium-ion batteries that use lithium iron phosphate as the positive electrode material and carbon as the negative electrode material. LFP electrodes typically use metal foil, such as aluminum foil, as the current collector. LFP batteries offer advantages such as high operating voltage, high energy density, long cycle life, good safety performance, low self-discharge rate, and no memory effect.

[0003] If the lithium iron phosphate on the electrodes of spent lithium iron phosphate batteries is not effectively recycled, it will not only waste resources but also pollute the environment. Related technologies typically employ chemical leaching processes, such as acid or alkali leaching, to separate the lithium iron phosphate from the electrodes for recycling. However, this generates large amounts of waste liquid and waste gas, causing severe environmental pollution, resulting in high subsequent processing costs, and is prone to secondary pollution. Utility Model Content

[0004] This application provides a lithium iron phosphate recycling device to solve the problems of high subsequent processing costs and easy secondary pollution caused by the recycling of lithium iron phosphate, thereby avoiding environmental pollution and reducing subsequent processing costs.

[0005] This application provides a lithium iron phosphate recycling device, comprising:

[0006] A pulverizing structure is used to pulverize lithium iron phosphate electrodes in waste lithium iron phosphate batteries.

[0007] The first screening element has its inlet connected to the outlet of the crushing structure;

[0008] A grinding device includes a hollow first shell and a roller structure. The first shell has an inlet and an outlet, both of which are connected to the hollow cavity of the first shell. The inlet is connected to the outlet of the first screening element. The roller structure is disposed inside the first shell and located between the inlet and the outlet. The roller structure is used to grind the initial screened material from the first screening element.

[0009] The roller structure includes at least one fixed roller and at least two rotating rollers; the fixed roller and the rotating rollers are arranged in a horizontal direction, and at least one fixed roller is arranged between two adjacent rotating rollers, and the roller gap between adjacent fixed rollers and rotating rollers and the roller gap between two adjacent rotating rollers are not greater than a first preset value.

[0010] The second screening element has its inlet connected to the outlet to screen the ground material discharged through the outlet to obtain lithium iron phosphate powder.

[0011] The lithium iron phosphate recycling device provided in this application comprises a crushing structure, a first screening element, a grinding device, and a second screening element. The outlet of the crushing structure is connected to the inlet of the first screening element, the outlet of the first screening element is connected to the inlet of the grinding device, and the outlet of the grinding device is connected to the inlet of the second screening element. In other words, the crushing structure, the first screening element, the grinding device, and the second screening element are sequentially connected. In practical use, the lithium iron phosphate electrodes from waste lithium iron phosphate batteries are first crushed using the crushing structure to obtain crushed material. Then, the crushed material is sieved through the first screening element to obtain primary sieved material. Finally, the primary sieved material is ground by the grinding device to obtain ground material. Because metals have good ductility, if there are metal materials in the initial screening material, they will stretch into metal foils under the grinding action of the grinding equipment. Since lithium iron phosphate is an inorganic compound, the lithium iron phosphate in the initial screening material will form smaller lithium iron phosphate powder under the grinding action. Thus, after grinding the initial screening material, a mixture containing metal foils and lithium iron phosphate powder can be obtained. Finally, the ground material is sieved through a second screening unit, effectively separating the metal foils and lithium iron phosphate powder, obtaining the lithium iron phosphate powder to be recycled. Compared with related technologies that use chemical reagent leaching processes, this method eliminates the need for chemical reagents, achieving physical recovery of lithium iron phosphate. This avoids environmental pollution caused by chemical reagents, prevents secondary pollution, reduces subsequent processing costs, and thus lowers the recovery cost of lithium iron phosphate to a certain extent. Simultaneously, it avoids the corrosion of metal foils caused by chemical reagents, improving the quality of metal recovery.

[0012] In addition, compared with the existing technology that mechanically strips lithium iron phosphate from the electrode, this method avoids the phenomenon of lithium iron phosphate residue on the electrode to a certain extent, realizes effective recovery of lithium iron phosphate, and improves the recovery efficiency and purity of lithium iron phosphate.

[0013] Furthermore, the grinding equipment includes a first housing and a roller structure. The first housing is a hollow structure, and it has an inlet and an outlet that communicate with its hollow cavity. The roller structure is located inside the first housing and between the inlet and the outlet. In this way, the initial screened material obtained by the first screening component enters the first housing through the inlet and is ground by the roller structure. After being ground by the roller structure, the resulting ground material can be discharged from the outlet under the action of gravity. The structure is simple, easy to implement, convenient to use, and helps to improve work efficiency.

[0014] Simultaneously, the primary screening material is ground using a roller structure, causing the metal material in the primary screening material to extend into metal foil under the grinding action of the roller structure, and causing the lithium iron phosphate in the primary screening material to form lithium iron phosphate powder with smaller particle size under the grinding action of the roller structure. This separates the lithium iron phosphate from the metal foil, achieving separation of lithium iron phosphate from the electrode with high separation efficiency.

[0015] Furthermore, the roller structure includes at least one fixed roller and at least two rotating rollers, which are arranged horizontally. A fixed roller is positioned between at least two adjacent rotating rollers, and the gap between the fixed roller and its adjacent rotating roller is not greater than a first preset value. The roller gap between the rotating roller and its adjacent rotating roller is also not greater than the first preset value. The structure is simple and easy to manufacture. Under the action of the rotating rollers, the primary screened material is continuously carried into the roller gap and subjected to gradually increasing extrusion and grinding force during the forced downward movement. This results in smaller particle sizes of lithium iron phosphate powder and granules, and the metal material is stretched into larger metal foils, thereby increasing the particle size difference between lithium iron phosphate powder and metal foils. This provides a better grinding effect on the primary screened material, facilitates the grinding and separation of lithium iron phosphate powder, and helps improve the separation and recovery efficiency of lithium iron phosphate powder.

[0016] In one possible design, the two outermost rollers of the roller structure in the horizontal direction are both rotating rollers, and when viewed from above in the horizontal direction, the two outermost rotating rollers rotate inward.

[0017] With the above scheme, the two outermost rollers of the roller structure in the horizontal direction are both rotating rollers, and when viewed from above in the horizontal direction, the two outermost rotating rollers rotate inward. In other words, the outermost rollers of the roller structure in its arrangement direction are rotating rollers, and when viewed from above in the arrangement direction, the two outermost rotating rollers of the roller structure rotate inward. In this way, after the primary screened material enters the grinding equipment, it can move towards the inner side of the roller structure and be continuously carried into the roller gap for grinding. To a certain extent, this avoids the accumulation of primary screened material on the inner wall of the grinding equipment above the roller structure. The design is reasonable, which helps to improve grinding efficiency and reduce the residue of primary screened material in the grinding equipment.

[0018] And / or, the gap between the two outermost rollers of the roller structure in the horizontal direction and the inner wall of the first housing is not greater than a second preset value.

[0019] The above scheme ensures that the gap between the two outermost rollers of the roller structure in the horizontal direction and the inner wall of the first housing is no greater than the second preset value. In other words, the gap between the outer contour of the roller structure in its arrangement direction and the inner wall of the first housing is no greater than the second preset value. This prevents the primary screening material from escaping between the roller structure and the inner wall of the first housing, allowing the primary screening material to move towards the inner side of the roller structure for grinding, thus improving the grinding efficiency and thereby improving the recovery efficiency of lithium iron phosphate.

[0020] And / or, at least one axial end of the rotating roller is rotatably connected to the inner wall of the first housing.

[0021] The above scheme allows the end of the rotating roller to be rotatably connected to the inner wall of the first housing. This allows the rotating roller to be directly mounted on the first housing, resulting in a smaller dimension between the axial end of the rotating roller and the inner wall of the first housing. This prevents the primary screening material from escaping between the axial end of the roller structure and the inner wall of the first housing, thus improving grinding efficiency and consequently improving the recovery efficiency of lithium iron phosphate.

[0022] And / or, the first preset value is 10μm-200μm.

[0023] By setting the roller gap to 10μm-200μm, the material being screened experiences greater extrusion and grinding force as it passes through the roller gap. This results in a suitable grinding time for the material, leading to a better grinding effect. This not only reduces the particle size of the lithium iron phosphate powder in the material but also allows the metal material to be stretched into larger metal foils, further increasing the particle size difference between the lithium iron phosphate powder and the metal foils. This further enhances the grinding effect on the material, facilitating the grinding and separation of the lithium iron phosphate powder, and ultimately improving the separation and recovery efficiency of the lithium iron phosphate powder.

[0024] And / or, the grinding pressure of the rotating roller is 50T-200T.

[0025] By setting the grinding pressure of the rotating roller to 50T-200T, the primary screening material is subjected to higher roller pressure at the roller gap. Under high pressure, on the one hand, the lithium iron phosphate powder and particles in the primary screening material are broken into smaller particles, and on the other hand, the metal materials in the primary screening material, such as metal fragments, are extended and deformed into larger metal foils, further improving the grinding efficiency of the roller structure.

[0026] And / or, the rotational speed of the rotating roller is 1m / s-5m / s.

[0027] By setting the rotation speed of the rotating roller to 1m / s-5m / s, while ensuring that the initial screening material has the same contact time at the roller gap, the number of times the initial screening material is ground per unit time is increased, thereby improving the grinding efficiency and thus making the recovery efficiency of lithium iron phosphate powder higher.

[0028] In one possible design, the roller structure has at least two stages, with the at least two stages of the roller structure arranged sequentially in the vertical direction, and the roller gaps of adjacent stages of the roller structure being staggered in the vertical direction.

[0029] The above scheme enables the grinding equipment to include a multi-stage roller structure, which is arranged sequentially in the vertical direction. The roller gaps of adjacent roller structures are staggered in the vertical direction. In other words, the roller gaps of the upper roller structure and the lower roller structure do not overlap in the vertical direction. Thus, the orthographic projection of the roller gap of the upper roller structure is located on the fixed or rotating roller of the lower roller structure. With this arrangement, the grinding material will not directly enter the roller gap of the lower roller structure after falling from the roller gap of the upper roller structure, increasing the contact time between the grinding material and the roller structure, thereby improving the grinding efficiency and further improving the recovery rate of lithium iron phosphate powder.

[0030] And / or, the feed port is located at the top of the first housing.

[0031] By setting the feed inlet at the top of the first housing, the material initially screened enters the first housing through the feed inlet and falls onto the roller structure under gravity for grinding. This saves energy, is convenient to use, and helps improve the efficiency of grinding.

[0032] And / or, the discharge port is located at the bottom of the first housing.

[0033] By setting the discharge port at the bottom of the first housing, the grinding material formed by the roller structure can be discharged under gravity, saving energy, making it convenient to use, and helping to improve the efficiency of grinding.

[0034] And / or, in the direction from the feed inlet to the discharge outlet, at least a portion of the inner cavity size of the first housing gradually decreases.

[0035] The above scheme makes the inner cavity size of at least part of the first shell gradually decrease in the direction from the feed inlet to the discharge outlet. That is, the inner cavity of the first shell is reduced in the direction from the feed inlet to the discharge outlet, so that the inner cavity of the first shell is larger on the feed inlet side and smaller on the discharge outlet side, which facilitates the timely discharge of the ground material into the downstream process and makes it convenient to use.

[0036] In one possible design, the crushing structure includes a hollow second shell and a crushing assembly;

[0037] The second housing has an openable inlet and outlet, and the crushing assembly is disposed inside the second housing and is rotatable relative to the second housing.

[0038] The above scheme incorporates a second housing and a crushing assembly. The second housing is hollow and has an inlet and an outlet communicating with its hollow cavity. Both the inlet and outlet of the second housing are openable and closable. The crushing assembly is housed within the second housing. Once the lithium iron phosphate electrode is placed into the second housing, the inlet is closed, allowing the crushing assembly to crush the lithium iron phosphate electrode in a relatively sealed environment. This prevents foreign matter from entering the second housing and contaminating the crushed material, thus improving the purity of the subsequent lithium iron phosphate powder. Furthermore, it prevents leakage of the crushed material, improving the recovery rate of the lithium iron phosphate powder.

[0039] In one possible design, the crushing assembly includes a drive element, a connecting rod, and multiple blades;

[0040] Multiple blades are spaced apart at least circumferentially along one end of the connecting rod, and the other end of the connecting rod is connected to the driving member. The driving member is used to drive the connecting rod to rotate relative to the second housing, so as to drive the multiple blades to rotate, so as to crush the lithium iron phosphate electrode.

[0041] The above scheme makes the crushing component include a driving component, a connecting rod and multiple blades. The driving component drives the connecting rod to rotate, and the rotation of the connecting rod drives the blades to rotate. The rotation of the blades can crush the lithium iron phosphate electrode. The structure is simple, easy to manufacture and convenient to use.

[0042] And / or, at least a portion of the inner cavity size of the second housing gradually decreases along the side away from the first screening member to the side closer to the first screening member.

[0043] The above scheme reduces the size of the inner cavity of the second shell from the side away from the first screening member to the side closer to the first screening member. That is, the inner cavity of the second shell is larger on the side away from the first screening member, and the inner cavity of the first shell is smaller on the side closer to the first screening member. In other words, the inner cavity of the second shell is larger on the inlet side and smaller on the outlet side, which facilitates the timely discharge of crushed materials into downstream processes and makes it convenient to use.

[0044] In one possible design, the first screening element includes a first vibrating screen.

[0045] The above scheme utilizes a first vibrating screen to vibrate and sieve the crushed material. The high-frequency vibration of the first vibrating screen causes the crushed material to bounce and slide strongly, which can quickly separate crushed materials of different particle sizes. The smaller part of the crushed material passes through the screen holes of the first vibrating screen to generate the initial screened material, while the larger part of the crushed material is screened out and remains above the first vibrating screen. The screening efficiency is high, and it is not easy to clog, which improves the stability and reliability of operation. Moreover, the structure is simple, easy to implement, and low in cost.

[0046] And / or, the mesh count of the first screening element is not greater than 80 mesh.

[0047] By using the above scheme, the mesh size of the first screening element is set to no more than 80 mesh, that is, the mesh size of the first screening element is relatively small. In this way, with the same length, the first vibrating screen has fewer sieve holes and larger hole diameters, so that the crushed material with the required particle size can pass through the sieve holes more fully to enter the subsequent grinding process. The screening efficiency is high, which facilitates the effective recovery of lithium iron phosphate material and helps to improve the recovery efficiency of lithium iron phosphate.

[0048] And / or, the second screening element includes a second vibrating screen.

[0049] The above scheme utilizes a second vibrating screen to sieve the grinding material. The high-frequency vibration of the second vibrating screen causes the grinding material to vibrate and slide strongly, which can quickly separate the metal foil and lithium iron phosphate powder. The lithium iron phosphate powder passes through the screen holes of the second vibrating screen and can be effectively recovered, while the metal foil is screened out and remains above the second vibrating screen. The screening efficiency is high, and it is not easy to clog, which improves the stability and reliability of operation. Moreover, the structure is simple, the operation is convenient, it is easy to implement, and the cost is low.

[0050] And / or, the mesh size of the second screening element is 100-120 mesh.

[0051] By setting the mesh size of the second screening component to 100-120 mesh, the number and diameter of the screen holes of the second vibrating screen are suitable for the same length. This facilitates the passage of powder in the grinding material through the screen holes and allows the metal foil to be screened out and left above the second vibrating screen, thus achieving effective recovery of lithium iron phosphate powder with high purity and good recovery effect.

[0052] In one possible design, the lithium iron phosphate recycling device also includes a first conveyor line and a storage bin;

[0053] One end of the first conveyor line is connected to the outlet of the second screening component, and the other end of the first conveyor line is connected to the storage bin.

[0054] The above scheme makes the lithium iron phosphate recycling device also include a first conveyor line and a storage bin. The outlet of the second screening unit and the storage bin are connected by the first conveyor line. In this way, the lithium iron phosphate powder screened by the second screening unit can be transported to the storage bin for storage by the first conveyor line, realizing the automated conveying and storage of lithium iron phosphate powder, which is convenient to use and improves work efficiency.

[0055] In one possible design, at least one foolproof structure is provided on the first conveyor line, the foolproof structure is electrically connected to the first conveyor line, the foolproof structure is used to detect the lithium iron phosphate powder, and the first conveyor line is used to stop when the foolproof structure detects a metallic foreign object in the lithium iron phosphate powder.

[0056] The foolproof structure includes a cleanliness analyzer.

[0057] The above solution involves setting up a foolproof structure on the first conveyor line to detect lithium iron phosphate powder. The first conveyor line can stop conveying lithium iron phosphate powder into the storage bin when the foolproof structure detects a metallic foreign object in the lithium iron phosphate powder. This method has a high degree of automation, is easy to use, and ensures the recycling efficiency of lithium iron phosphate powder to a certain extent.

[0058] In one possible design, the lithium iron phosphate recycling device further includes a second conveyor line, one end of which is connected to the outlet of the second screening element, and the other end of which is connected to the feed inlet of the grinding equipment.

[0059] The above scheme further includes a second conveyor line in the lithium iron phosphate recovery device. The second conveyor line connects the outlet of the second screening unit to the inlet of the grinding equipment. In this way, the lithium iron phosphate powder screened by the second screening unit can be returned to the grinding equipment for further grinding through the second conveyor line. In other words, the setting of the second conveyor line realizes the re-grinding of lithium iron phosphate powder, further improving the separation efficiency of lithium iron phosphate and metal, thereby further improving the recovery purity of lithium iron phosphate powder. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the structure of a lithium iron phosphate recycling device according to an embodiment of this application.

[0061] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0062] Figure 3 This is a schematic diagram of the structure of a lithium iron phosphate recycling device according to another embodiment of this application.

[0063] Figure 4 This is a schematic diagram of the structure of a lithium iron phosphate recycling device according to another embodiment of this application.

[0064] Figure 5 This is a schematic diagram of the structure of a lithium iron phosphate recycling device according to another embodiment of this application.

[0065] Figure 6 This is a bar chart showing the test results of aluminum and copper content in lithium iron phosphate powder obtained by the lithium iron phosphate recovery device described in this application embodiment, compared with the aluminum and copper content in lithium iron phosphate powder obtained by prior art.

[0066] Figure 7 This is a schematic diagram comparing the processing performance and electrical performance of lithium iron phosphate powder obtained by the lithium iron phosphate recovery device described in this application embodiment with the processing performance and electrical performance of lithium iron phosphate powder obtained by the prior art.

[0067] Explanation of reference numerals in the attached drawings: 1. Crushing structure; 11. Connecting rod; 12. Blade; 2. First screening component; 3. Grinding equipment; 4. Second screening component; 5. Foolproof structure; 6. Storage bin; 7. First conveyor line; 8. Second conveyor line; 9. Roller structure; 91. Fixed roller; 92. Rotating roller. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0069] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0070] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0071] In this article, the term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists, A and B exist simultaneously, or B exists. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0072] The directional terms appearing in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the lithium iron phosphate recycling device of this application. For example, in the description of this application, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0073] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0074] In the description of this application, unless otherwise stated, "multiple" means two or more (including two), and similarly, "multiple groups" means two or more (including two groups).

[0075] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, "connection" or "linkage" in mechanical structures can refer to a physical connection, such as a fixed connection, for example, a connection secured by screws, bolts, or other spacers; a physical connection can also be a detachable connection, such as a snap-fit ​​or interlocking connection; a physical connection can also be an integral connection, such as a connection formed by welding, bonding, or integral molding. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. In circuit structures, "connection" or "linkage" can refer not only to a physical connection but also to an electrical connection or a signal connection. For example, it can be a direct connection, i.e., a physical connection, or an indirect connection through at least one intermediate component, as long as the circuit is connected; it can also refer to the internal connection of two components. Signal connection can refer not only to signal connection through a circuit but also to signal connection through a medium, such as radio waves. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0076] refer to Figure 1 As shown, this embodiment provides a lithium iron phosphate recycling device, which includes a crushing structure 1, a first screening component 2, a grinding device 3, and a second screening component 4.

[0077] Specifically, the crushing structure 1 is used to crush the lithium iron phosphate electrode sheets in waste lithium iron phosphate batteries; the inlet of the first screening element 2 is connected to the outlet of the crushing structure 1; the feed inlet of the grinding equipment 3 is connected to the outlet of the first screening element 2, and the grinding equipment 3 is used to grind the initial screening material screened by the first screening element 2; the inlet of the second screening element 4 is connected to the discharge outlet of the grinding equipment 3 to screen the ground material discharged from the discharge outlet of the grinding equipment 3 to obtain lithium iron phosphate powder.

[0078] In practice, firstly, the lithium iron phosphate electrode sheets from the waste lithium iron phosphate batteries are placed into the crushing structure 1. The crushing structure 1 is then activated, and it crushes the waste lithium iron phosphate electrode sheets into pulverized materials, including powder, small fragments, and fine particles. This facilitates subsequent processing and helps improve the recycling efficiency of lithium iron phosphate. The fragments and particles are relatively small, typically ranging from millimeters to micrometers in size.

[0079] The lithium iron phosphate electrode is pulverized by the pulverizing structure 1, so that non-metallic materials such as lithium iron phosphate on the lithium iron phosphate electrode are detached from the metal foil to a certain extent, which facilitates the subsequent separation of non-metallic materials such as lithium iron phosphate from metal impurities.

[0080] Next, the pulverized material formed by the pulverizing structure 1 is placed into the first screening unit 2 for sieving to obtain primary screening material. Sieving the pulverized material allows smaller portions, such as powder, small fragments, and particles, to pass through the sieve holes, forming primary screening material that can enter subsequent steps, facilitating the recovery of lithium iron phosphate. Meanwhile, larger portions, such as larger fragments and particles, are removed to prevent them from flowing into subsequent steps and affecting grinding efficiency, thus contributing to improved lithium iron phosphate recovery efficiency.

[0081] In some implementations, for example, the larger portions of the crushed material that have been screened out can be added back into the crushing structure 1 for secondary crushing. This not only avoids the waste of materials caused by incomplete crushing of lithium iron phosphate electrodes to a certain extent, but also improves the recovery efficiency of lithium iron phosphate to a certain extent.

[0082] For example, the pulverized material is sieved through the first screening element 2. The powder, as well as smaller fragments and particles, pass through the sieve and proceed to subsequent steps. Larger fragments and particles do not pass through, thus achieving the effect of separating large particles from the pulverized material.

[0083] Then, the initial screened material obtained from the first screening unit 2 is placed into the grinding equipment 3 and ground to obtain the ground material. The ground material includes metal foil and lithium iron phosphate powder.

[0084] In practice, the grinding equipment 3 grinds the powder and smaller fragments and particles screened by the first screening component 2. On one hand, this allows the lithium iron phosphate material on the fragments and particles to be fully detached, improving the recovery efficiency of lithium iron phosphate. On the other hand, it reduces the particle size of the lithium iron phosphate powder and particles, further enhancing the recovery efficiency and effect. Thirdly, it allows metal materials, such as metal fragments, in the initial screening material to extend into metal foils, increasing the particle size difference between the lithium iron phosphate powder and the metal impurities, facilitating the separation of metal materials from the lithium iron phosphate powder, and achieving effective recovery of the lithium iron phosphate powder.

[0085] In other words, after the grinding equipment 3 grinds the initial screened material, it obtains grinding materials such as metal foil and lithium iron phosphate powder with smaller particle size.

[0086] Finally, the ground material generated by the grinding equipment 3 is placed into the second screening unit 4 for sieving to obtain the lithium iron phosphate powder that needs to be recycled.

[0087] By sieving the ground materials, on the one hand, the lithium iron phosphate powder can pass through the sieve holes, facilitating its recycling; on the other hand, the metal foil will not pass through the sieve holes, remaining above them, thus achieving effective separation between the metal foil and the lithium iron phosphate powder and improving the recycling efficiency of the lithium iron phosphate powder.

[0088] refer to Figures 1 to 5 As shown, the grinding equipment 3 includes a hollow first shell and a roller structure 9. The first shell has an inlet and an outlet, both of which are connected to the hollow cavity of the first shell. The roller structure 9 is disposed inside the first shell and located between the inlet and the outlet. The roller structure 9 is used to grind the primary screened material screened by the first screening component 2.

[0089] In other words, the grinding equipment 3 includes a first housing and a roller structure 9. The first housing is a hollow structure, and an inlet and an outlet are provided on the first housing and communicate with the hollow cavity therein. The roller structure 9 is set inside the first housing and is located between the inlet and the outlet. In this way, the initial screened material obtained by the first screening component 2 enters the first housing through the inlet and is ground by the roller structure 9. After being ground by the roller structure 9, the ground material can be discharged from the outlet under the action of gravity. The structure is simple, easy to implement, convenient to use, and helps to improve work efficiency.

[0090] Simultaneously, the primary screening material is ground using the roller structure 9, causing the metal material in the primary screening material to extend into metal foil under the grinding action of the roller structure 9, and causing the lithium iron phosphate in the primary screening material to form lithium iron phosphate powder with smaller particle size under the grinding action of the roller structure 9, thereby separating lithium iron phosphate from the metal foil and realizing the separation of lithium iron phosphate from the electrode with high separation efficiency.

[0091] refer to Figures 1 to 5 As shown, the roller structure 9 includes at least one fixed roller 91 and at least two rotating rollers 92; the fixed roller 91 and the rotating roller 92 are arranged in a horizontal direction, and a fixed roller 91 is provided between at least two adjacent rotating rollers 92, and the roller gap between adjacent fixed rollers 91 and rotating rollers 92 and the roller gap between two adjacent rotating rollers 92 are not greater than a first preset value.

[0092] In practice, the fixed roller 91 and the rotating roller 92 are arranged in a horizontal direction. At least one fixed roller 91 is set between two adjacent rotating rollers 92. That is, a fixed roller 91 can be set between every two adjacent rotating rollers 92, i.e., the fixed roller 91 and the rotating roller 92 are set alternately. Alternatively, a fixed roller 91 can be set between two adjacent rotating rollers 92, i.e., there is a case where no fixed roller is set between two rotating rollers.

[0093] The fixed roller 91 is stationary and does not rotate on its own. The rotating roller 92 can rotate on its own, for example, it can be driven to rotate by a motor.

[0094] In practice, the initial screened material enters the grinding equipment 3 and falls above the roller structure 9. Under the action of the rotating roller 92, the material enters the roller gap. As it moves downwards within the gap, it experiences gradually increasing extrusion and grinding force, allowing fragments and lithium iron phosphate material on the particles to be fully removed. This causes the lithium iron phosphate powder and particles to break down, forming smaller particles that are discharged from below the roller gap, further improving the recovery efficiency and effect of lithium iron phosphate. Simultaneously, metal materials, such as metal fragments, extend into metal foil sheets that are discharged from below the roller gap, increasing the particle size difference between the lithium iron phosphate powder and the metal impurities. This facilitates subsequent separation of the metal materials and lithium iron phosphate powder, achieving effective recovery of the lithium iron phosphate powder.

[0095] By including at least one fixed roller 91 and at least two rotating rollers 92 in the roller structure 9, the fixed roller 91 and the rotating rollers 92 are arranged in a horizontal direction, and a fixed roller 91 is arranged between at least two partially adjacent rotating rollers 92. Moreover, the roller gap between the fixed roller 91 and its adjacent rotating roller 92 is not greater than a first preset value, and the roller gap between the rotating roller 92 and its adjacent rotating roller 92 is not greater than the first preset value. The structure is simple and easy to manufacture. Under the action of the rotating rollers 92, the primary screened material is continuously carried into the roller gap and subjected to gradually increasing extrusion and grinding force during the forced downward movement. This makes the particle size of lithium iron phosphate powder and particles smaller, and the metal material is extended into larger metal foils, thereby increasing the particle size difference between lithium iron phosphate powder and metal foils. The grinding effect on the primary screened material is better, which facilitates the grinding and separation of lithium iron phosphate powder and helps to improve the separation efficiency and recovery efficiency of lithium iron phosphate powder.

[0096] In some embodiments, the first preset value may be, for example, 10μm-200μm.

[0097] By setting the roller gap to 10μm-200μm, the material being screened experiences greater extrusion and grinding force as it passes through the roller gap. This results in a suitable grinding time for the material, leading to a better grinding effect. This not only reduces the particle size of the lithium iron phosphate powder in the material but also allows the metal material to be stretched into larger metal foils, further increasing the particle size difference between the lithium iron phosphate powder and the metal foils. This further enhances the grinding effect on the material, facilitating the grinding and separation of the lithium iron phosphate powder, thereby increasing the separation and recovery efficiency of the lithium iron phosphate powder.

[0098] For specific implementation, refer to Figure 1 , Figures 3 to 5 As shown, the outlet of the crushing structure 1 and the inlet of the first screening component 2 can be directly connected, for example. Of course, in other implementations, the outlet of the crushing structure 1 and the inlet of the first screening component 2 can also be connected via pipes, conveyor lines, etc.

[0099] Similarly, the outlet of the first screening component 2 can be directly connected to the inlet on the first housing, or it can be connected through a pipe, conveyor line, etc. The outlet on the first housing can be directly connected to the inlet of the second screening component 4, or it can be connected through a pipe, conveyor line, etc.

[0100] It should be noted that the aforementioned waste lithium iron phosphate batteries can be either defective products generated during the battery production process or used and discarded lithium iron phosphate batteries.

[0101] The lithium iron phosphate recycling device provided in this application comprises a crushing structure 1, a first screening element 2, a grinding device 3, and a second screening element 4. The outlet of the crushing structure 1 is connected to the inlet of the first screening element 2, the outlet of the first screening element 2 is connected to the inlet of the grinding device 3, and the outlet of the grinding device 3 is connected to the inlet of the second screening element 4. In other words, the crushing structure 1, the first screening element 2, the grinding device 3, and the second screening element 4 are sequentially connected. In practical use, the lithium iron phosphate electrode sheets from waste lithium iron phosphate batteries are first crushed using the crushing structure 1 to obtain crushed material. Then, the crushed material is sieved using the first screening element 2 to obtain primary sieved material. Finally, the primary sieved material is ground using the grinding device 3 to obtain ground material. Because metals have good ductility, if there are metal materials in the initial screening material, they will stretch into metal foils under the grinding action of grinding equipment 3. Since lithium iron phosphate is an inorganic compound, the lithium iron phosphate in the initial screening material will form smaller lithium iron phosphate powder under the grinding action of grinding equipment 3. Thus, after grinding the initial screening material, grinding equipment 3 can obtain a mixture containing metal foils and lithium iron phosphate powder. Finally, the ground material is sieved through the second screening unit 4, effectively separating the metal foils and lithium iron phosphate powder to obtain the lithium iron phosphate powder to be recycled. Compared with the chemical reagent leaching process in related technologies, this method eliminates the need for chemical reagents, achieving physical recovery of lithium iron phosphate. This avoids environmental pollution caused by chemical reagents and prevents secondary pollution, reducing subsequent processing costs and thus lowering the recovery cost of lithium iron phosphate to a certain extent. Simultaneously, it avoids the corrosion of metal foils caused by chemical reagents, improving the quality of metal recovery.

[0102] In addition, compared with the existing technology that mechanically strips lithium iron phosphate from the electrode, this method avoids the phenomenon of lithium iron phosphate residue on the electrode to a certain extent, realizes effective recovery of lithium iron phosphate, and improves the recovery efficiency and purity of lithium iron phosphate.

[0103] In some embodiments, reference Figure 1 , Figures 3 to 5 As shown, the feed inlet of the grinding equipment 3 can be set at the top of the first housing. After the initial screened material enters the first housing through the feed inlet, it can fall onto the roller structure 9 under the action of gravity and be ground. This makes it easier for the roller structure 9 to grind the material, saves energy, is convenient to use, and helps to improve the efficiency of grinding.

[0104] Of course, the feed inlet of the grinding equipment 3 can be located on the side of the first housing, for example.

[0105] In some embodiments, reference Figure 1 , Figures 3 to 5 As shown, the discharge port of the grinding equipment 3 is located at the bottom of the first housing. In this way, the grinding material formed by the roller structure 9 can be discharged under the action of gravity, which saves energy, is convenient to use, and helps to improve the efficiency of grinding.

[0106] Of course, the discharge port of the grinding equipment 3 can also be located on the side of the first housing.

[0107] In some embodiments, reference Figure 1 , Figures 3 to 5 As shown, in the direction from the inlet to the outlet (reference) Figure 1 In the X direction, at least part of the inner cavity size of the first shell gradually decreases.

[0108] In other words, the inner cavity of the first housing is narrowed in the direction from the feed inlet to the discharge outlet, so that the inner cavity of the first housing is larger on the feed inlet side and smaller on the discharge outlet side, which facilitates the timely discharge of the ground material into the downstream process and makes it convenient to use.

[0109] For example, the grinding equipment 3 may be a roller press.

[0110] In other implementations, the grinding equipment 3 can be, for example, a cyclone mill.

[0111] In some embodiments, reference Figures 1 to 5 As shown, the two outermost rollers of the roller structure 9 in the horizontal direction are both rotating rollers 92, and when viewed from above in the horizontal direction, the two outermost rotating rollers 92 rotate inward.

[0112] In other words, the outermost part of the roller structure 9 in its arrangement direction is the rotating roller 92. Moreover, viewed from above in the arrangement direction, the two outermost rotating rollers 92 of the roller structure 9 rotate inward. In this way, after the primary screened material enters the grinding equipment 3, it can move towards the inner side of the roller structure 9 and be continuously carried into the roller gap for grinding. To a certain extent, this avoids the accumulation of primary screened material on the inner wall of the grinding equipment 3 above the roller structure 9. The design is reasonable and helps to improve grinding efficiency and reduce the residue of primary screened material in the grinding equipment 3.

[0113] In some embodiments, the gap between the two outermost rollers of the roller structure 9 in the horizontal direction and the inner wall of the first housing is not greater than a second preset value.

[0114] In other words, the gap between the outer contour of the roller structure 9 in its arrangement direction and the inner wall of the first shell is not greater than the second preset value. This can prevent the primary screening material from escaping between the roller structure 9 and the inner wall of the first shell, so that the primary screening material can move toward the inner side of the roller structure 9 to be ground, thereby improving the grinding efficiency and thus improving the recovery efficiency of lithium iron phosphate.

[0115] In practice, the second preset value can be, for example, 2μm-5μm, which can both avoid interference with the inner wall of the first shell and effectively prevent the escape of the initial screening material.

[0116] In some embodiments, at least one axial end of the rotating roller 92 is rotatably connected to the inner wall of the first housing.

[0117] By rotatably connecting the end of the rotating roller 92 to the inner wall of the first housing, the rotating roller 92 can be directly mounted on the first housing, thereby making the size between the axial end of the rotating roller 92 and the inner wall of the first housing relatively small. This prevents the primary screening material from escaping between the axial end of the roller structure 9 and the inner wall of the first housing, improving the grinding efficiency and thus improving the recovery efficiency of lithium iron phosphate.

[0118] In other embodiments, the rotating roller 92 may be connected to a bracket, which is fixed to the inner wall of the first housing.

[0119] In some embodiments, the grinding pressure of the rotating roller 92 is 50T-200T.

[0120] By setting the grinding pressure of the rotating roller 92 to 50T-200T, the primary screening material is subjected to higher roller pressure at the roller gap. Under high pressure, on the one hand, the lithium iron phosphate powder and particles in the primary screening material are broken into smaller particles, and on the other hand, the metal materials in the primary screening material, such as metal fragments, are extended and deformed into larger metal foils, further improving the grinding efficiency of the roller structure 9.

[0121] In some embodiments, the rotational speed of the rotating roller 92 is 1 m / s to 5 m / s.

[0122] If the rotation speed of the rotating roller 92 is too low, the material in the initial screening will stay in the roller gap for too long, which will block the roller gap and affect the normal operation of the grinding equipment 3.

[0123] If the rotation speed of the rotating roller 92 is too high, the material in the primary screening will be discharged from the bottom of the roller gap relatively quickly under the drive of the rotating roller 92. As a result, the time for the material in the primary screening to be squeezed and ground in the roller gap is too short, and the grinding is insufficient.

[0124] Therefore, by setting the rotation speed of the rotating roller 92 to 1m / s-5m / s, while ensuring that the initial screening material has the same residence and contact time at the roller gap, the number of times the initial screening material is ground per unit time is increased, thereby improving the grinding efficiency and thus making the recovery efficiency of lithium iron phosphate powder higher.

[0125] In some embodiments, reference Figures 1 to 5 As shown, the roller structure 9 has at least two stages, and the at least two stages of roller structure 9 are arranged sequentially in the vertical direction, and the roller gaps of adjacent two stages of roller structure 9 are staggered in the vertical direction.

[0126] In other words, the roll gaps of the upper roller structure 9 and the lower roller structure 9 do not overlap in the vertical direction. Thus, the orthographic projection of the roll gap of the upper roller structure 9 is located on the fixed roller 91 or rotating roller 92 of the lower roller structure 9. With this configuration, the grinding material will not directly enter the roll gap of the lower roller structure 9 after falling from the roll gap of the upper roller structure 9, increasing the contact time between the grinding material and the roller structure 9, thereby improving the grinding efficiency and further improving the recovery rate of lithium iron phosphate powder.

[0127] By making the roller structure 9 at least two stages, the grinding equipment 3 can perform at least two stages of grinding on the primary screened material. This means that the primary screened material will be ground at least twice after entering the grinding equipment 3. In other words, the grinding material generated in the previous stage will enter the next stage to continue grinding, which increases the grinding time of the primary screened material, thereby improving the grinding efficiency and further improving the recovery rate of lithium iron phosphate powder.

[0128] In some embodiments, reference Figure 1 , Figures 3 to 5 As shown, the crushing structure 1 includes a hollow second shell and a crushing assembly; the second shell has an openable inlet and an outlet, and the crushing assembly is disposed inside the second shell and can rotate relative to the second shell.

[0129] By including a second housing and a crushing component in the crushing structure 1, the second housing is hollow and has an inlet and an outlet communicating with its hollow cavity. Both the inlet and outlet of the second housing can be opened and closed. The crushing component is disposed inside the second housing. After the lithium iron phosphate electrode sheet is placed into the second housing, the inlet of the second housing is closed. This allows the crushing component to crush the lithium iron phosphate electrode sheet in a relatively sealed environment. On the one hand, this prevents foreign matter from entering the second housing and contaminating the crushed material, thus improving the purity of the subsequent lithium iron phosphate powder. On the other hand, it prevents leakage of the crushed material, improving the recovery rate of the lithium iron phosphate powder.

[0130] In practice, the inlet of the second housing can be located at its top, and the outlet of the second housing can be located at its bottom, which facilitates the insertion of lithium iron phosphate electrode sheets and the discharge of crushed materials, thus helping to improve work efficiency.

[0131] In some embodiments, reference Figure 1 , Figures 3 to 5 As shown, the crushing assembly includes a drive unit (not shown), a connecting rod 11, and a plurality of blades 12. The plurality of blades 12 are spaced apart at least circumferentially along one end of the connecting rod 11, and the other end of the connecting rod 11 is connected to the drive unit. The drive unit is used to drive the connecting rod 11 to rotate relative to the second housing, so as to drive the plurality of blades 12 to rotate, thereby crushing the lithium iron phosphate electrode sheet.

[0132] In practical use, the connecting rod 11 is driven to rotate by the driving component. When the connecting rod 11 rotates, it drives the blade 12 to rotate. The rotation of the blade 12 can crush the lithium iron phosphate electrode sheet. The structure is simple, easy to manufacture, and convenient to use.

[0133] In a specific implementation, some blades 12 can be arranged circumferentially along the bottom end of the connecting rod 11, and some blades 12 can be arranged axially along one side of the bottom end of the connecting rod 11, which results in higher efficiency in crushing lithium iron phosphate electrode sheets.

[0134] In some implementations, each blade 12 can be directly connected to the connecting rod 11, which is flexible. If a blade 12 is damaged, it can be replaced directly, saving costs.

[0135] In other implementations, all blades 12 can be an integral structure for easy assembly.

[0136] In some embodiments, reference Figure 1 , Figures 3 to 5 As shown, along the side away from the first screening member 2 to the side closer to the first screening member 2 (reference) Figure 1 In the X direction, at least part of the inner cavity size of the second shell gradually decreases.

[0137] By reducing the size of the inner cavity of the second shell along the direction from the side away from the first screening member 2 to the side closer to the first screening member 2, that is, the inner cavity of the second shell is larger on the side away from the first screening member 2 and smaller on the side closer to the first screening member 2, that is, the inner cavity of the second shell is larger on the inlet side and smaller on the outlet side, it is convenient for the crushed material to be discharged into the downstream process in a timely manner, making it easy to use.

[0138] For example, the crushing structure 1 can be a crusher, which has a simple structure, is easy to implement, has low cost, and has a good crushing effect.

[0139] In other embodiments, the shredding structure 1 may be, for example, an angle grinder, a bi-shaft shredder, etc.

[0140] In some embodiments, the first screening element 2 includes a first vibrating screen.

[0141] The crushed material is vibrated and sieved using a first vibrating screen. The high-frequency vibration of the first vibrating screen causes the crushed material to bounce and slide strongly, which can quickly separate crushed materials of different particle sizes. The smaller part of the crushed material passes through the screen holes of the first vibrating screen to generate the primary screen material, while the larger part of the crushed material is screened out and remains above the first vibrating screen. The screening efficiency is high and it is not easy to clog, which improves the stability and reliability of operation. Moreover, the structure is simple, easy to implement, and low in cost.

[0142] In practice, the mesh size of the first screening element 2 is no more than 80 mesh, which has a high screening efficiency for lithium iron phosphate in the crushed material and a good screening effect.

[0143] The mesh count of the first screening component 2 refers to the number of sieve holes per inch of length of the first vibrating screen.

[0144] Meanwhile, the mesh size of the first screening component 2 is set to no more than 80 mesh, that is, the mesh size of the first screening component 2 is relatively small. In this way, with the same length, the first vibrating screen has fewer screen holes and larger hole diameters, so that the crushed material with the required particle size can pass through the screen holes more fully to enter the subsequent grinding process. The screening efficiency is high, which facilitates the effective recovery of lithium iron phosphate material and helps to improve the recovery efficiency of lithium iron phosphate.

[0145] If the mesh size of the first screening element 2 is greater than 80 mesh, that is, the mesh size of the first screening element 2 is relatively large, then under the same length, the first vibrating screen has more screen holes and smaller hole diameters, resulting in a lower throughput of crushed materials. In other words, the screening efficiency of crushed materials is low, which is not conducive to the recovery of lithium iron phosphate materials and affects the recovery efficiency of lithium iron phosphate.

[0146] In other embodiments, the first screening element 2 may be, for example, an air classifier that uses density differences to separate metallic materials and non-metallic materials such as lithium iron phosphate from the pulverized material.

[0147] In some embodiments, the second screening component 4 includes a second vibrating screen.

[0148] The grinding material is sieved using a second vibrating screen. The high-frequency vibration of the second vibrating screen causes the grinding material to bounce and slide strongly, which can quickly separate the metal foil and lithium iron phosphate powder. The lithium iron phosphate powder passes through the screen holes of the second vibrating screen and can be effectively recovered, while the metal foil is screened out and remains above the second vibrating screen. The sieving efficiency is high and it is not easy to clog, which improves the stability and reliability of operation. Moreover, the structure is simple, easy to operate, easy to implement, and low in cost.

[0149] In practice, the second screening element 4 has a mesh size of 100-120 mesh, which provides high screening efficiency and good screening effect for lithium iron phosphate powder in the grinding material.

[0150] The mesh count of the second screening component 4 refers to the number of sieve holes per inch of length of the second vibrating screen.

[0151] By setting the mesh size of the second screening component 4 to 100-120 mesh, the number and diameter of the screen holes of the second vibrating screen are suitable under the same length, which facilitates the passage of powder in the grinding material through the screen holes and allows the metal foil to be screened out and left above the second vibrating screen, thus achieving effective recovery of lithium iron phosphate powder with high purity and good recovery effect.

[0152] If the mesh size of the second screening component 4 is greater than 120 mesh, that is, the mesh size of the second screening component 4 is relatively large, then under the same length, the second vibrating screen has too many screen holes and the hole diameter is too small, which makes the screen holes easy to be blocked by powders such as lithium iron phosphate. This results in a low throughput of lithium iron phosphate powder and affects the recycling of lithium iron phosphate materials.

[0153] If the mesh size of the second screening component 4 is less than 100 mesh, that is, the mesh size of the second screening component 4 is small, then under the same length, the screen holes of the second vibrating screen are too few and the aperture is too large, which makes it easy for metal foil to pass through the screen holes, resulting in more metal impurities in the recovered lithium iron phosphate powder, which affects the purity of the recovered lithium iron phosphate material.

[0154] In other embodiments, the second screening element 4 may be, for example, an air classifier that uses density differences to separate metallic materials and non-metallic materials such as lithium iron phosphate from the ground material.

[0155] In some embodiments, reference Figure 3 and Figure 5 As shown, the lithium iron phosphate recycling device also includes a first conveyor line 7 and a storage bin 6. One end of the first conveyor line 7 is connected to the outlet of the second screening element 4, and the other end of the first conveyor line 7 is connected to the storage bin 6.

[0156] In other words, the inlet of the first conveyor line 7 is connected to the outlet of the second screening component 4, and the outlet of the first conveyor line 7 is connected to the storage bin 6. That is, the outlet of the second screening component 4 and the storage bin 6 are connected through the first conveyor line 7. In this way, the lithium iron phosphate powder screened by the second screening component 4 can be transported to the storage bin 6 for storage through the first conveyor line 7, realizing the automated conveying and storage of lithium iron phosphate powder, which is convenient to use and improves work efficiency.

[0157] In practice, the lithium iron phosphate powder screened by the second screening component 4 enters the first conveyor line 7 after exiting the outlet of the second screening component 4. Under the conveying action of the first conveyor line 7, it enters the storage bin 6, realizing the automatic recycling and storage of lithium iron phosphate powder, improving the automation level of lithium iron phosphate powder recycling, and making recycling more convenient. It also facilitates subsequent use.

[0158] In some embodiments, reference Figure 3 and Figure 5 As shown, at least one foolproof structure 5 is provided on the first conveyor line 7. The foolproof structure 5 is electrically connected to the first conveyor line 7. The foolproof structure 5 is used to detect lithium iron phosphate powder. The first conveyor line 7 is used to stop when the foolproof structure 5 detects a metal foreign object in the lithium iron phosphate powder.

[0159] By setting a foolproof structure 5 on the first conveyor line 7, the lithium iron phosphate powder is detected by the foolproof structure 5. Moreover, the first conveyor line 7 can stop conveying lithium iron phosphate powder into the storage bin 6 when the foolproof structure 5 detects that there are metal foreign objects in the lithium iron phosphate powder. The automation level is high, the use is convenient, and the recycling efficiency of lithium iron phosphate powder is guaranteed to a certain extent.

[0160] In some implementations, multiple anti-mistake structures 5 are provided on the first conveyor line 7. The multiple anti-mistake structures 5 are spaced apart along the length of the first conveyor line 7. This arrangement improves the detection effect of metal foreign objects in lithium iron phosphate powder and further enhances the recycling purity of lithium iron phosphate powder.

[0161] For example, refer to Figure 2 As shown, three foolproof structures 5 are spaced apart along the length of the first conveyor line 7.

[0162] In practice, the foolproof structure 5 can be, for example, a cleanliness analyzer.

[0163] For example, a cleanliness analyzer can analyze the cleanliness of lithium iron phosphate powder by illuminating it with a light source and measuring whether the powder reflects light.

[0164] Lithium iron phosphate powder is an inorganic compound powder, typically gray or black in appearance. Its appearance means it doesn't reflect light like metal, so it won't reflect light when passing through a cleanliness analyzer. Metallic foreign objects, however, reflect light due to their smooth surface and metallic luster. Therefore, light reflection can be used to identify metallic foreign objects, and the cleanliness analyzer can collect the light when these objects pass through it.

[0165] In practice, the cleanliness analyzer detects the lithium iron phosphate powder on the first conveyor line 7 by illuminating it with a light source.

[0166] If there are no metallic foreign objects in the lithium iron phosphate powder, the cleanliness analyzer will not collect reflected light when the lithium iron phosphate powder passes through the cleanliness analyzer, and it is considered that there are no metallic foreign objects in the lithium iron phosphate powder that has passed through the cleanliness analyzer.

[0167] If lithium iron phosphate powder contains metallic foreign matter, the cleanliness analyzer will detect the reflected light as the powder passes through it. This indicates the presence of metallic foreign matter in the powder, and the first conveyor line 7 will stop operating. This ensures that the lithium iron phosphate powder containing metallic foreign matter does not enter the storage bin 6, thereby improving the recycling quality of the lithium iron phosphate powder.

[0168] In some embodiments, reference Figure 4 and Figure 5 As shown, the lithium iron phosphate recycling device also includes a second conveyor line 8, one end of which is connected to the outlet of the second screening piece 4, and the other end of which is connected to the feed inlet of the grinding equipment 3.

[0169] The outlet of the second screening component 4 and the inlet of the grinding equipment 3 are connected by the second conveyor line 8. In this way, the lithium iron phosphate powder screened by the second screening component 4 can be returned to the grinding equipment 3 for further grinding through the second conveyor line 8. In other words, the setting of the second conveyor line 8 realizes the re-grinding of lithium iron phosphate powder, further improving the separation efficiency of lithium iron phosphate and metal, thereby further improving the recovery purity of lithium iron phosphate powder.

[0170] In some implementations, refer to Figure 4 As shown, the outlet of the second conveyor line 8 and the outlet of the second screening component 4 can be directly connected.

[0171] In other implementations, refer to Figure 5 As shown, one end of the second conveyor line 8 is connected to the outlet of the second screening component 4 through the first conveyor line 7. That is, the second conveyor line 8 is connected to the outlet of the second screening component 4 through the inlet side of the first conveyor line 7. In this way, when the foolproof structure 5 detects that there are metal foreign objects in the lithium iron phosphate powder, the lithium iron phosphate powder on the first conveyor line 7 can be returned to the grinding equipment 3 through the second conveyor line 8 for re-grinding of the lithium iron phosphate powder.

[0172] In practice, when the foolproof structure 5 detects a metallic foreign object in the lithium iron phosphate powder, the lithium iron phosphate powder on the first conveyor line 7 can be returned to the grinding equipment 3 via the second conveyor line 8. The grinding equipment 3 then continues to grind the returned lithium iron phosphate powder, further improving the automation level and recycling efficiency of lithium iron phosphate powder, and ensuring the recycling quality of lithium iron phosphate powder.

[0173] In summary, the specific operation of the lithium iron phosphate recycling device provided in this embodiment for recycling lithium iron phosphate from the lithium iron phosphate electrode sheets of waste lithium iron phosphate batteries is as follows:

[0174] Waste lithium iron phosphate (LFP) electrode sheets are fed into the crushing structure 1 for crushing to obtain crushed material. The crushed material is then sieved through the first screening unit 2 to obtain preliminary screening material. The preliminary screening material is then fed into the grinding equipment 3 for grinding to obtain ground material, which includes metal foil and lithium iron phosphate powder. The ground material is then sieved through the second screening unit 4 to obtain the lithium iron phosphate powder to be recycled. Compared with the chemical reagent leaching process in related technologies, this method eliminates the need for chemical reagents, achieving physical recycling of lithium iron phosphate. This avoids environmental pollution caused by chemical reagents and prevents secondary pollution, reducing subsequent processing costs and thus lowering the recycling cost of lithium iron phosphate to a certain extent. Simultaneously, it avoids the corrosion of metal foil caused by chemical reagents, improving the quality of metal recycling.

[0175] In addition, compared with the existing technology of mechanically stripping lithium iron phosphate from the electrode, this method avoids the phenomenon of lithium iron phosphate residue on the electrode to a certain extent, realizes the effective recycling of lithium iron phosphate material, and improves the recycling efficiency and purity of lithium iron phosphate.

[0176] Furthermore, the outlet of the second screening component 4 is connected to the storage bin 6 via the first conveyor line 7, and a foolproof structure 5 is installed on the first conveyor line 7 to detect the lithium iron phosphate powder on the first conveyor line 7. When the foolproof structure 5 does not alarm, the lithium iron phosphate powder on the first conveyor line 7 is conveyed into the storage bin 6; when the foolproof structure 5 alarms, the lithium iron phosphate powder on the first conveyor line 7 is conveyed to the grinding equipment 3 via the second conveyor line 8 for further grinding. In other words, only when the foolproof structure 5 does not alarm can the lithium iron phosphate powder enter the storage bin 6 via the first conveyor line 7 for storage, ensuring the recovery efficiency and quality of the lithium iron phosphate powder.

[0177] In other words, the crushing, grinding, and sieving processes effectively separate lithium iron phosphate from waste lithium iron phosphate electrodes, improving recycling efficiency. Simultaneously, the foolproof structure 5 on the first conveyor line 7 prevents metallic foreign objects from entering the storage bin 6, ensuring the quality of the recycled lithium iron phosphate powder. Furthermore, combined with ICP testing of the lithium iron phosphate powder in the storage bin 6, the operating parameters of the roller press can be adjusted, further guaranteeing the recycling efficiency and quality of the lithium iron phosphate powder.

[0178] At the same time, compared with the method of using a large amount of chemical reagents to recover lithium iron phosphate, the recovery cost is reduced and the environmental pollution caused by chemical reagents is avoided.

[0179] The following four examples and three comparative examples more intuitively demonstrate the performance of lithium iron phosphate after being processed by the lithium iron phosphate recovery device using this embodiment.

[0180] Example 1:

[0181] 50 kg of waste lithium iron phosphate electrode sheets are fed into the crushing structure 1 for crushing to obtain crushed material. The crushed material is then sieved through the first screening device 2 with a screen mesh of 80 mesh to obtain preliminary screening material. The preliminary screening material is then fed into the grinding equipment 3 for grinding. The grinding equipment 3 includes upper and lower roller structures 9. Each roller structure 9 has four rotating rollers 92 and three fixed rollers 91. From the horizontal direction, the two outermost rotating rollers 92 of each roller structure 9 rotate inward. The pressure of the rotating rollers 92 is 100T, the roller gap is 100μm, and the rotation speed of the rotating rollers 92 is 2m / s. After three grinding processes, the ground material is sieved through the second screening device 4 with a screen mesh of 150 mesh to obtain lithium iron phosphate powder.

[0182] 5g of lithium iron phosphate powder was extracted from storage compartment 6 for IPC testing, processing performance testing, and electrical performance testing. The test results are referenced. Figure 6 and Figure 7 .

[0183] Example 2:

[0184] 50 kg of waste lithium iron phosphate electrode sheets are fed into the crushing structure 1 for crushing to obtain crushed material. The crushed material is then sieved through the first screening device 2 with a screen mesh of 80 mesh to obtain preliminary screening material. The preliminary screening material is then fed into the grinding equipment 3 for grinding. The grinding equipment 3 includes an upper and lower three-stage roller structure 9. The uppermost roller structure 9 has six rotating rollers 92 and three fixed rollers 91, the middle roller structure 9 has four rotating rollers 92 and two fixed rollers 91, and the lowermost roller structure 9 has two rotating rollers 92 and one fixed roller 91. Horizontally, the two outermost rotating rollers 92 of each roller structure 9 rotate inwards. The pressure of the rotating rollers 92 is 100T, the roller gap is 100μm, and the rotation speed of the rotating rollers 92 is 2m / s. After three grinding processes, the ground material is sieved through the second screening device 4 with a screen mesh of 150 mesh to obtain lithium iron phosphate powder.

[0185] 5g of lithium iron phosphate powder was drawn from storage warehouse 6 for ICP testing, processing performance testing, and electrical performance testing. The test results are referenced. Figure 6 and Figure 7 .

[0186] Example 3:

[0187] 50 kg of waste lithium iron phosphate electrode sheets are fed into the crushing structure 1 for crushing to obtain crushed material. The crushed material is then sieved through the first screening device 2 with a screen mesh of 80 mesh to obtain preliminary screening material. The preliminary screening material is then fed into the grinding equipment 3 for grinding. The grinding equipment 3 includes upper and lower roller structures 9. Each roller structure 9 has four rotating rollers 92 and three fixed rollers 91. From the horizontal direction, the two outermost rotating rollers 92 of each roller structure 9 rotate inward. The pressure of the rotating rollers 92 is 100T, the roller gap is 100μm, and the rotation speed of the rotating rollers 92 is 2m / s. After one grinding process, the ground material is sieved through the second screening device 4 with a screen mesh of 150 mesh to obtain lithium iron phosphate powder.

[0188] 5g of lithium iron phosphate powder was drawn from storage warehouse 6 for ICP testing, processing performance testing, and electrical performance testing. The test results are referenced. Figure 6 and Figure 7 .

[0189] Example 4:

[0190] 50 kg of waste lithium iron phosphate electrode sheets are fed into the crushing structure 1 for crushing to obtain crushed material. The crushed material is then sieved through the first screening device 2 with a screen mesh of 80 mesh to obtain preliminary screening material. The preliminary screening material is then fed into the grinding equipment 3 for grinding. The grinding equipment 3 includes upper and lower roller structures 9. Each roller structure 9 has four rotating rollers 92 and three fixed rollers 91. Viewed horizontally, the two outermost rotating rollers 92 of each roller structure 9 rotate inward. The pressure of the rotating rollers 92 is 50T, the roller gap is 200μm, and the rotation speed of the rotating rollers 92 is 3m / s. After one grinding process, the ground material is sieved through the second screening device 4 with a screen mesh of 150 mesh to obtain lithium iron phosphate powder.

[0191] 5g of lithium iron phosphate powder was drawn from storage warehouse 6 for ICP testing, processing performance testing, and electrical performance testing. The test results are referenced. Figure 6 and Figure 7 .

[0192] As shown in Examples 1 and 2, when the mesh size of the first screening element 2, the mesh size of the second screening element 4, the number of rolling cycles, and the operating parameters of the grinding equipment 3 are the same, the lithium iron phosphate powder obtained by the three-stage roller structure 9 in Example 2 has better processing performance and electrical performance than the lithium iron phosphate powder obtained by the two-stage roller structure 9 in Example 1. In other words, when the mesh size of the first screening element 2, the mesh size of the second screening element 4, the number of rolling cycles, and the operating parameters of the grinding equipment 3 are the same, the more layers of the roller structure 9, the better the processing performance and electrical performance of the lithium iron phosphate powder. (Test results are referenced.) Figure 6 As shown.

[0193] Furthermore, refer to Figure 6 and Figure 7 As shown, the copper and aluminum contents of the lithium iron phosphate powder obtained in Example 2 are lower than those of the lithium iron phosphate powder obtained in Example 1. Therefore, it can be seen that when the mesh size of the first screening element 2, the mesh size of the second screening element 4, the number of rolling cycles, and the working parameters of the grinding equipment 3 are the same, the more layers of the roller structure 9, the lower the copper and aluminum contents in the lithium iron phosphate powder, and the higher the recovery purity.

[0194] As shown in Examples 1 and 3, when the mesh size of the first screening element 2, the mesh size of the second screening element 4, the layering, structure, and operating parameters of the roller structure 9 inside the grinding equipment 3 are the same, the processing performance and electrical performance of the lithium iron phosphate powder obtained after three roller pressing processes in Example 1 are better than those of the lithium iron phosphate powder obtained after one roller pressing process in Example 3. In other words, when the mesh size of the first screening element 2, the mesh size of the second screening element 4, the layering, structure, and operating parameters of the roller structure 9 inside the grinding equipment 3 are the same, the more times the roller pressing process is performed, the better the processing performance and electrical performance of the lithium iron phosphate powder. (Test results are referenced.) Figure 6 As shown.

[0195] As can be seen from Examples 3 and 4, when the mesh size of the first screening element 2 is the same, the mesh size of the second screening element 4 is the same, the layers and structure of the roller structure 9 inside the grinding equipment 3 are the same, and the number of rolling cycles is the same, although the grinding pressure, roller gap, and rotational speed of the rotating roller 92 in the grinding equipment 3 of Example 3 are respectively greater than those in Example 4, the processing performance of the lithium iron phosphate powder obtained in Example 3 is the same as that obtained in Example 4, and the electrical performance of the lithium iron phosphate powder obtained in Example 3 is approximately equal to that obtained in Example 4. In other words, when the mesh size of the first screening element 2 is the same, the mesh size of the second screening element 4 is the same, the layers and structure of the roller structure 9 inside the grinding equipment 3 are the same, and the number of rolling cycles is the same, the processing performance and electrical performance of the lithium iron phosphate powder are approximately equal. Figure 6 As shown.

[0196] Furthermore, refer to Figure 6 and Figure 7 As shown, the copper and aluminum contents of the lithium iron phosphate powder obtained in Example 3 are greater than those of the lithium iron phosphate powder obtained in Example 4. Therefore, it can be seen that when the mesh size of the first screening piece 2 is the same, the mesh size of the second screening piece 4 is the same, the layers and structure of the roller structure 9 in the grinding equipment 3 are the same, and the number of roller pressing times are the same, the greater the grinding pressure of the grinding equipment 3 and / or the smaller the roller gap and / or the greater the rotation speed of the rotating roller 92, the lower the copper and aluminum contents in the recovered lithium iron phosphate powder, and the higher the purity of the recovered lithium iron phosphate powder.

[0197] Comparative Example 1

[0198] ICP testing, processing performance testing, and electrical performance testing were conducted on lithium iron phosphate material recovered through pyrometallurgical methods. The test results are referenced. Figure 6 and Figure 7 As shown.

[0199] Comparative Example 2

[0200] The lithium iron phosphate powder recovered through mechanical stripping underwent ICP testing, processing performance testing, and electrical performance testing. The test results are referenced. Figure 6 and Figure 7 As shown.

[0201] Comparative Example 3

[0202] Unprocessed lithium iron phosphate powder (the raw material for making lithium iron phosphate electrodes) was subjected to ICP testing, processing performance testing, and electrical performance testing. The test results are referenced. Figure 6 and Figure 7 As shown.

[0203] Therefore, it can be concluded that, for reference Figure 6and Figure 7 As shown, the copper and aluminum content of the lithium iron phosphate powder recovered in Comparative Example 1 is the second highest, which is much higher than that in Comparative Example 3. Furthermore, the processing performance and electrical performance of the lithium iron phosphate powder recovered in Comparative Example 1 are much lower than those in Comparative Example 3.

[0204] The lithium iron phosphate powder recovered in Comparative Example 2 had the highest copper and aluminum content, the worst processing performance, and the lowest electrical performance. In other words, the copper and aluminum content of the lithium iron phosphate powder recovered in Comparative Example 2 was much higher than that in Comparative Example 3, and the processing and electrical performance of the lithium iron phosphate powder recovered in Comparative Example 2 were much lower than those in Comparative Example 3.

[0205] Using the lithium iron phosphate recycling device provided in this embodiment, the lithium iron phosphate powders recycled from waste lithium iron phosphate electrodes in Examples 1, 2, 3, and 4 have copper content, aluminum content, processing performance, and electrical performance that are not significantly different from those in Comparative Example 3. Among them, after optimizing the parameters of the grinding equipment 3, it can be seen that the copper content, aluminum content, processing performance, and electrical performance of the lithium iron phosphate powder recycled in Example 2 are closest to those in Comparative Example 3.

[0206] In other words, comparing Example 2 with Comparative Example 3, it can be seen that the copper content, aluminum content, processing performance, and electrical performance of the two are quite similar. That is, by using the lithium iron phosphate recycling device provided in this example to recycle lithium iron phosphate, the recycled lithium iron phosphate material on the waste lithium iron phosphate electrode can reach the level of the unprocessed lithium iron phosphate powder in Comparative Example 3, which can be used for subsequent production.

[0207] It is evident that the lithium iron phosphate material recovered by the lithium iron phosphate recovery device provided in this embodiment is far superior to that recovered by pyrometallurgical and mechanical stripping methods in related technologies. This achieves efficient recovery of lithium iron phosphate without affecting its subsequent processing performance and electrical properties. At the same time, it effectively prevents metals such as aluminum and copper from entering the storage chamber, thereby improving the purity of the recovered material.

Claims

1. A recovery device of lithium iron phosphate, characterized by, include: The crushing structure (1) is used to crush lithium iron phosphate electrode sheets in waste lithium iron phosphate batteries. The first screening element (2) has its inlet connected to the outlet of the crushing structure (1); Grinding equipment (3) includes a hollow first shell and a roller structure (9). The first shell has an inlet and an outlet, both of which are connected to the hollow cavity of the first shell. The inlet is connected to the outlet of the first screening component (2). The roller structure (9) is disposed inside the first shell and located between the inlet and the outlet. The roller structure (9) is used to grind the primary screening material screened by the first screening component (2). The roller structure (9) includes at least one fixed roller (91) and at least two rotating rollers (92); the fixed roller (91) and the rotating rollers (92) are arranged in a horizontal direction, and at least one fixed roller (91) is arranged between two adjacent rotating rollers (92), and the roller gap between adjacent fixed rollers (91) and rotating rollers (92) and the roller gap between two adjacent rotating rollers (92) are not greater than a first preset value; The second screening element (4) has its inlet connected to the outlet to screen the ground material discharged through the outlet to obtain lithium iron phosphate powder.

2. The lithium iron phosphate recovery device according to claim 1, characterized in that, The two outermost rollers of the roller structure (9) in the horizontal direction are both rotating rollers (92), and when viewed from above in the horizontal direction, the two outermost rotating rollers (92) rotate inward. And / or, the gap between the two outermost rollers of the roller structure (9) in the horizontal direction and the inner wall of the first housing is not greater than a second preset value; And / or, at least one axial end of the rotating roller (92) is rotatably connected to the inner wall of the first housing; And / or, the first preset value is 10μm-200μm; And / or, the grinding pressure of the rotating roller (92) is 50T-200T; And / or, the rotational speed of the rotating roller (92) is 1m / s-5m / s.

3. The recovery device of lithium iron phosphate according to claim 1, characterized in that, The roller structure (9) is at least two-stage, and the at least two-stage roller structures (9) are arranged sequentially in the vertical direction, and the roller gaps of adjacent two-stage roller structures (9) are staggered in the vertical direction; And / or, the feed inlet is located at the top of the first housing; And / or, the discharge port is located at the bottom of the first housing; And / or, in the direction from the feed inlet to the discharge outlet, at least a portion of the inner cavity size of the first housing gradually decreases.

4. The recovery device of lithium iron phosphate according to claim 1, characterized in that, The crushing structure (1) includes a hollow second shell and a crushing component; The second housing has an openable inlet and outlet, and the crushing assembly is disposed inside the second housing and is rotatable relative to the second housing.

5. The recovery device of lithium iron phosphate according to claim 4, characterized in that, The crushing assembly includes a drive component, a connecting rod (11), and multiple blades (12); Multiple blades (12) are arranged at least circumferentially at one end of the connecting rod (11), and the other end of the connecting rod (11) is connected to the driving member. The driving member is used to drive the connecting rod (11) to rotate relative to the second housing, so as to drive the multiple blades (12) to rotate, so as to crush the lithium iron phosphate electrode sheet. And / or, along the side away from the first screening member (2) to the side closer to the first screening member (2), at least part of the inner cavity size of the second housing gradually decreases.

6. The recovery device for lithium iron phosphate according to any one of claims 1 to 5, characterized in that, The first screening component (2) includes a first vibrating screen. And / or, the mesh count of the first screening element (2) is not greater than 80 mesh; And / or, the second screening element (4) includes a second vibrating screen; And / or, the mesh size of the second screening element (4) is 100-120 mesh.

7. The recovery device of lithium iron phosphate according to any one of claims 1 to 5, characterized in that, The lithium iron phosphate recycling device also includes a first conveyor line (7) and a storage bin (6); One end of the first conveyor line (7) is connected to the outlet of the second screening component (4), and the other end of the first conveyor line (7) is connected to the storage bin (6).

8. The recovery device for lithium iron phosphate according to claim 7, characterized by At least one anti-mistake structure (5) is provided on the first conveyor line (7). The anti-mistake structure (5) is electrically connected to the first conveyor line (7). The anti-mistake structure (5) is used to detect the lithium iron phosphate powder. The first conveyor line (7) is used to stop when the anti-mistake structure (5) detects that there is a metal foreign object in the lithium iron phosphate powder. The foolproof structure (5) includes a cleanliness analyzer.

9. The recovery device of lithium iron phosphate according to claim 7, characterized in that, The lithium iron phosphate recycling device also includes a second conveyor line (8), one end of which is connected to the outlet of the second screening element (4), and the other end of which is connected to the feed inlet of the grinding equipment (3).

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