Equipment and method for extracting lithium from positive electrode black powder of lithium iron phosphate battery

Abstract

The invention relates to equipment and a method for extracting lithium from positive electrode black powder of a lithium iron phosphate battery. The equipment comprises a leaching mechanism, an evaporation and concentration device, a lithium precipitation device, a demagnetizing tank, a demagnetizing assembly, a cleaning assembly, a filtering tank and a heating tank, the evaporation and concentration device is connected with the leaching mechanism; the lithium precipitation device is connected with the evaporation and concentration device; the demagnetizing tank is connected with the lithium precipitation device; the demagnetizing assembly is rotationally arranged on the demagnetizing tank; the demagnetizing assembly is provided with an accommodating cavity; the accommodating cavity is communicated with the interior of the demagnetizing tank; four demagnetizing parts are arranged in the accommodating cavity; a partition plate is arranged between every two adjacent demagnetizing parts; the four partition plates divide the accommodating cavity into a demagnetizing cavity, a to-be-cleaned cavity, a cleaning cavity and a to-be-demagnetized cavity; the cleaning assembly is arranged on the demagnetizing tank and corresponds to the cleaning cavity; the cleaning assembly is used for cleaning the demagnetizing part in the cleaning cavity; the filtering tank is connected with the demagnetizing tank; the heating tank is connected with the filtering tank. The demagnetizing device has the technical effects of prolonging the service life of the demagnetizing part and improving the demagnetizing efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of waste lithium battery recycling, and in particular to a device and method for extracting lithium from black powder in the positive electrode of a lithium iron phosphate battery. Background Art

[0002] Vehicles powered by new energy sources, such as plug-in hybrids, pure electric vehicles, and fuel cells, typically use lithium batteries as their power source. Direct disposal of used lithium batteries severely damages the environment, necessitating their recycling and reuse. The cathode material of used iron phosphate batteries contains lithium-rich black powder, which is the primary target for recycling. Battery-grade lithium carbonate must be extracted from this black powder. During the lithium carbonate extraction process, the lithium carbonate slurry must be demagnetized to remove metallic impurities such as iron and nickel.

[0003] Currently, permanent magnets or electromagnets are used to adsorb magnetic particles. Before use, a scraper is usually required to scrape off the magnetic particles adsorbed on the electromagnet. Long-term cleaning can easily damage the surface of the electromagnet, and the cleaning time is long.

[0004] Patent CN215277357U discloses a purification device for recovering lithium carbonate from lithium iron phosphate batteries. The device comprises a reactor equipped with a stirring device, an electromagnetism demagnetizer mounted on the reactor's upper inner wall, and a separator connected to the reactor's bottom outlet. The stirring device thoroughly stirs low-purity lithium carbonate and a certain proportion of water within the reactor. Iron doped within the lithium carbonate is separated from the lithium carbonate. The electromagnetism demagnetizer is energized to adsorb magnetic materials such as iron within the reactor. The demagnetization process in this patent utilizes the electromagnetism demagnetizer. However, due to the humid environment in which the demagnetization takes place, magnetic materials remain adhered to each other even after the demagnetizer is powered off, preventing them from falling off and requiring a scraper to remove them. Drying of the magnetic materials increases their adhesion, making scraping more difficult. Furthermore, the electromagnetism demagnetizer has a limited demagnetization capacity, making it inadequate for lithium carbonate solutions containing a high concentration of magnetic materials, thus compromising the demagnetization effect.

[0005] With respect to the above-mentioned related technologies, the inventors believe that there are defects in that the magnetic material on the electromagnet is difficult to clean when demagnetizing lithium carbonate slurry and the electromagnet is easily damaged during cleaning. Summary of the Invention

[0006] In order to solve the above technical problems, the present application provides a device and method for extracting lithium from positive electrode black powder of lithium iron phosphate batteries.

[0007] This application provides a lithium iron phosphate battery cathode black powder lithium extraction equipment, which adopts the following technical solutions: A lithium iron phosphate battery cathode black powder lithium extraction device includes: Leaching mechanism; the leaching mechanism is used to acid-leach the black powder and prepare an acid-leach solution; an evaporation and concentration device connected to the leaching mechanism; the evaporation and concentration device is used to evaporate and concentrate the acid leaching solution; a lithium precipitation device connected to the evaporation and concentration device; a demagnetization tank connected to the lithium precipitation device; A demagnetization assembly is rotatably mounted on the demagnetization tank; the demagnetization assembly comprises a receiving chamber; the receiving chamber is in communication with the interior of the demagnetization tank; four demagnetization sections are provided in the receiving chamber; partitions are provided between adjacent demagnetization sections; the four partitions divide the receiving chamber into a demagnetization chamber, a chamber to be cleaned, a cleaning chamber, and a chamber to be demagnetized; a cleaning assembly, disposed on the demagnetization tank and corresponding to the cleaning chamber; the cleaning assembly is used to clean the demagnetization portion in the cleaning chamber; A filter tank connected to the demagnetization tank; A heating tank is connected to the filter tank.

[0008] By adopting the above technical solution, the black powder is converted into lithium carbonate slurry through the leaching mechanism, evaporation concentration device and lithium precipitation device, and then introduced into the demagnetization tank; by rotating the demagnetization assembly in the demagnetization tank, the four demagnetization parts on the demagnetization assembly are switched in turn in the cleaning assembly and the demagnetization tank, ensuring that the demagnetization part in the demagnetization tank continuously absorbs and cleans magnetic substances, so that the demagnetization part can fully absorb the magnetic substances in the lithium carbonate slurry; the demagnetization part uses an electromagnet, and when the cleaning assembly is cleaning, the power is cut off, causing some magnetic substances to fall off. Under the action of the cleaning assembly, the magnetic substances adhering to the demagnetization part are cleaned away, avoiding the use of a scraper to scrape the surface of the demagnetization part, thereby increasing the service life of the demagnetization part and ensuring its demagnetization effect; because the four demagnetization parts are separated by the partition, the four demagnetization parts are formed into independent individuals. If one of the demagnetization parts is damaged, it does not need to be replaced in full. The partition can also separate the accommodating cavity and the interior of the demagnetization tank, ensuring that the accommodating cavity and the interior of the demagnetization tank do not interfere with each other.

[0009] Preferably, the demagnetization component includes: A silo is provided on the outer wall of the demagnetization tank and is in communication with the interior of the demagnetization tank; a plurality of demagnetization parts are located in the silo; a first temporary storage chamber and a second temporary storage chamber are provided at the bottom of the silo; the first temporary storage chamber is located directly below the chamber to be cleaned; and the second temporary storage chamber is located directly below the cleaning chamber; The first rotating shaft is rotatably arranged on the demagnetization tank and passes through the warehouse body; the four demagnetization parts are evenly arranged on the first rotating shaft along the circumferential direction; and the four partitions are evenly arranged on the first rotating shaft along the circumferential direction.

[0010] By adopting the above technical solution, the rotation of the shaft drives the four demagnetization parts to rotate. During the rotation, part of the lithium carbonate slurry in the demagnetization tank will enter the warehouse body. Therefore, a first temporary storage chamber and a second temporary storage chamber are opened at the bottom of the warehouse body, and the lithium carbonate slurry can enter the first temporary storage chamber; the magnetic material removed by the cleaning component falls into the second receiving chamber, so that the lithium carbonate slurry and the cleaned magnetic material are automatically isolated.

[0011] Preferably, the demagnetization unit includes: A mounting seat, wherein four mounting seats are evenly arranged on the first rotating shaft along the circumferential direction; a plurality of water outlet holes are opened at the bottom of the mounting seat; a dispersion cavity is formed in the mounting seat and is connected to the plurality of water outlet holes; a water inlet is opened at the top of the mounting seat; the water inlet is connected to the dispersion cavity; A plurality of demagnetizing components are provided on the mounting seat; the plurality of demagnetizing components are located between the plurality of water outlet holes; Wherein, the cleaning component has elastic freedom to slide vertically; the cleaning component has a water supply port; the water supply port is connected to or disconnected from the water inlet.

[0012] By adopting the above technical solution, a dispersion chamber is set in the mounting base, and the water from the cleaning component is transmitted to each water outlet through the dispersion chamber. The sprayed water can flow downward along the surface of the demagnetizer, and flush the adsorbed magnetic material into the second temporary storage chamber below; compared with directly flushing the surface of the demagnetizer with water, flushing downward along the length direction of the demagnetizer can ensure that all parts of the demagnetizer can be flushed, avoiding sanitary dead corners and improving the cleaning effect.

[0013] Preferably, the cleaning component comprises: A water storage tank is provided on the demagnetization tank; A connecting cylinder is rotatably mounted on the demagnetizing tank; the inner wall of the connecting cylinder is intermittently provided with four groups of internal threads; the four groups of internal threads are evenly distributed along the circumference of the connecting cylinder; and a falling channel is formed between adjacent internal threads; A water supply pipe is vertically slidably disposed in the connecting cylinder; four groups of threaded strips are intermittently provided on the outer wall of the water supply pipe; the four groups of threaded strips respectively cooperate with the four groups of internal threads; the bottom of the water supply pipe is connected to or disconnected from the water inlet; A water supply hose, one end of which is connected to the water storage tank and the other end of which is connected to the top of the water supply pipe; A water supply pump is arranged in the water storage tank; the water supply pump is connected to the water supply hose.

[0014] By adopting the above technical solution, four groups of internal threads are provided on the inner wall of the connecting cylinder, and four groups of threaded strips respectively cooperating with the four groups of internal threads are provided on the outer wall of the water supply pipe. After the connecting cylinder is rotated, the water supply pipe can be driven to move upward; the bottom of the water supply pipe can be separated from the water inlet; and the water supply pipe is prevented from being pulled when the mounting seat rotates; after the threaded strip is separated from the internal thread, the threaded strip can slide down along the falling channel, so that the water supply pipe is inserted downward into the water inlet, thereby realizing the separation and connection of the cleaning component and the mounting seat, so that each group of demagnetization parts can be reasonably cleaned.

[0015] Preferably, the lithium iron phosphate battery positive electrode black powder lithium extraction equipment further includes a driving component; the driving component includes: A third rotating shaft is coaxially arranged in the demagnetization tank; a spiral plate is arranged on the circumference of the third rotating shaft; a residual gear coaxially fixed on the third rotating shaft; A first gear is coaxially fixed on the first rotating shaft; the first gear is meshed with the residual gear; The second gear is coaxially fixed on the connecting cylinder; the second gear is meshed with the first gear.

[0016] By adopting the above technical solution, a third rotating shaft is arranged to rotate in the demagnetization tank, and a threaded plate is arranged on the third rotating shaft; after the third rotating shaft rotates, the threaded plate can transfer the lithium carbonate slurry in the middle of the demagnetization tank to both sides, ensuring that the demagnetization part can contact all the lithium carbonate slurry in the demagnetization tank, thereby improving the demagnetization efficiency; after the third rotating shaft rotates, it can also intermittently drive the first gear through the residual gear to make the mounting seat rotate intermittently, thereby achieving the effect of demagnetizing and cleaning four groups of demagnetization parts in sequence; the first gear can drive the second gear, and then drive the connecting cylinder to rotate, thereby achieving the effect of synchronous movement of the mounting seat and the cleaning component, so that the cleaning and demagnetization processes of the demagnetization part are smoothly connected, thereby improving the demagnetization efficiency.

[0017] Preferably, the demagnetization unit further includes: Two sealing plates are relatively slidably arranged on both sides of the water inlet; the top of the sealing plate is provided with an arc-shaped guide surface; the bottom of the water supply pipe abuts against the two arc-shaped guide surfaces.

[0018] Two elastic members; one end of the two elastic members is respectively arranged on the two sealing plates; the other ends of the two elastic members are respectively connected to the mounting seats; the two elastic members are respectively used to push the two sealing plates to abut against each other.

[0019] By adopting the above technical solution, two sealing plates are set at the water inlet, which can prevent the lithium carbonate solution in the demagnetization tank from splashing into the water inlet, thereby preventing the water inlet from being blocked and avoiding waste of raw materials; an arc-shaped guide surface is set on the sealing plate, so that the two sealing plates can be automatically separated after the water supply pipe is inserted into the water inlet; after the water supply pipe is detached, the two elastic parts push the two sealing plates to abut against each other, thereby achieving the effect of automatic closing and separation of the sealing plates, avoiding manpower and improving work efficiency.

[0020] Preferably, a rubber tube is connected to the bottom of the water supply tube; an abutment ring is connected to the bottom of the rubber tube; and the abutment ring abuts against the two arc-shaped guide surfaces.

[0021] By adopting the above technical solution, since the mounting seat and the water supply pipe move synchronously, in order to ensure that the water supply pipe and the mounting seat do not interfere with each other during movement, a rubber tube is connected to the bottom of the water supply pipe; when the mounting seat rotates, the rubber tube undergoes elastic deformation until the rubber tube is separated from the mounting seat, and then the rubber tube is restored; by connecting an abutment ring at the bottom of the rubber tube, the two sealing plates can be smoothly pushed apart after the water supply pipe moves downward, and the sealing plate is prevented from damaging the bottom surface of the rubber tube, thereby improving the service life of the rubber tube.

[0022] Preferably, the cleaning component further comprises: a water baffle, disposed in the water supply pipe; a second rotating shaft, rotatably disposed in the water supply pipe; a circular baffle disposed on the second rotating shaft; a peripheral side of the circular baffle abutting against the inner wall of the water supply pipe; A coil spring is wound around the second rotating shaft; one end of the coil spring is connected to the second rotating shaft, and the other end is connected to the water supply pipe.

[0023] By adopting the above technical solution, a water baffle is set in the water supply pipe, so that the outlet of the water supply pipe becomes narrower, which has the effect of increasing water pressure, thereby improving the cleaning quality of magnetic materials on the surface of the demagnetization piece; after the water supply pump in the water storage tank stops working, there is still accumulated water in the water supply pipe, but the accumulated water is not pressurized. After flowing downward onto the demagnetization piece, the cleaning effect is small, which causes a large amount of water waste over a long period of time; therefore, a second rotating shaft and a circular baffle are provided to cooperate with the water baffle; the water pressurized by the water baffle can also rush downward Hit one side of the circular baffle to make it rotate around the second shaft, thereby connecting the water supply pipe with the water inlet of the mounting base; after stopping cleaning, the water supply pump in the water storage tank stops working, and the circular baffle is only affected by the gravity of the water. Under the action of the coil spring, the shaft is reset, and the circular baffle blocks the outlet of the water supply pipe again to prevent the water in the water supply pipe from continuing to flow down, thereby avoiding waste of water resources; after the circular baffle rotates, a pressurized channel can also be formed under the baffle to further increase the water pressure and improve the cleaning quality of the magnetic material on the surface of the demagnetizer.

[0024] Preferably, the leaching mechanism includes a slurry mixing tank, a leaching tank and a plate-frame compressor; the slurry mixing tank, the leaching tank and the plate-frame compressor are connected by a pipeline; the lithium sinking device includes a lithium sinking tank, a centrifuge and a slurry mixing tank; the lithium sinking tank is connected to the evaporation concentration device, the centrifuge and the slurry mixing tank through the pipeline.

[0025] A method for extracting lithium from black powder in the positive electrode of a lithium iron phosphate battery comprises: Step S1: adding black powder and water into the slurry mixing tank and stirring, and adding the mixture of black powder and water into the leaching tank through the pipeline; introducing concentrated sulfuric acid and hydrogen peroxide into the leaching tank for acid leaching to obtain a leachate; sending the leachate into the plate and frame filter press through the pipeline for solid-liquid separation to obtain a filtrate; Step S2: passing the filtrate into a filter tank for impurity removal and filtration, and then passing it into the evaporation and concentration device to evaporate excess water and obtain a concentrated solution; Step S3: pumping the concentrated liquid into the lithium precipitation tank through a pipeline, adding sodium carbonate solution in proportion to carry out lithium precipitation reaction; after the reaction is complete, passing it into a centrifuge for separation to obtain lithium carbonate solid; Step S4: adding the lithium carbonate solid into a slurry mixing tank and adding water to stir, then introducing carbon dioxide gas to perform a carbonization reaction, and after the carbonization is completed, passing the solid into the demagnetization tank and the filter tank in sequence to perform filtration and impurity removal, and then passing the solid into the heating tank to perform heating and decomposition to obtain a lithium carbonate slurry; Step S5: passing the lithium carbonate slurry into a centrifuge for solid-liquid separation, and drying, screening, deironing, crushing and packaging the separated lithium carbonate solid to obtain high-purity battery-grade lithium carbonate.

[0026] In summary, this application includes at least one of the following beneficial technical effects: By adopting the above technical solution, the black powder is converted into lithium carbonate slurry through the leaching mechanism, evaporation concentration device and lithium precipitation device, and then introduced into the demagnetization tank; by rotating the demagnetization assembly in the demagnetization tank, the four demagnetization parts on the demagnetization assembly are switched in turn in the cleaning assembly and the demagnetization tank, ensuring that the demagnetization part in the demagnetization tank continuously absorbs and cleans magnetic substances, so that the demagnetization part can fully absorb the magnetic substances in the lithium carbonate slurry; the demagnetization part uses an electromagnet, and when the cleaning assembly is cleaning, the power is cut off, causing some magnetic substances to fall off. Under the action of the cleaning assembly, the magnetic substances adhering to the demagnetization part are cleaned away, avoiding the use of a scraper to scrape the surface of the demagnetization part, thereby increasing the service life of the demagnetization part and ensuring its demagnetization effect; because the four demagnetization parts are separated by the partition, the four demagnetization parts are formed into independent individuals. If one of the demagnetization parts is damaged, it does not need to be replaced in full. The partition can also separate the accommodating cavity and the interior of the demagnetization tank, ensuring that the accommodating cavity and the interior of the demagnetization tank do not interfere with each other.

[0027] A water baffle is provided in the water supply pipe to narrow the outlet of the water supply pipe, thereby increasing the water pressure and improving the cleaning quality of the magnetic material on the surface of the demagnetizing member. After the water supply pump in the water storage tank stops working, water still remains in the water supply pipe, but the accumulated water has not been pressurized. After flowing downward onto the demagnetizing member, the cleaning effect is relatively small, resulting in a large amount of water waste over a long period of time. Therefore, a second rotating shaft and a circular baffle are provided to cooperate with the water baffle. The water pressurized by the water baffle can also impact downward on one side of the circular baffle, causing the circular baffle to rotate around the second rotating shaft, thereby connecting the water supply pipe with the water inlet of the mounting seat. After cleaning is stopped, the water supply pump in the water storage tank stops working, and the circular baffle is only subjected to the gravity of the water. Under the action of the coil spring, the rotating shaft is reset, and the circular baffle re-blocks the outlet of the water supply pipe, preventing the water in the water supply pipe from continuing to flow downward, thereby avoiding water waste. After the circular baffle rotates, a pressurized channel can also be formed below the water baffle, further increasing the water pressure and improving the cleaning quality of the magnetic material on the surface of the demagnetizing member. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the process of extracting lithium from the positive electrode black powder of lithium iron phosphate batteries.

[0029] Figure 2 This is an axial side view of the lithium iron phosphate battery positive electrode black powder lithium extraction equipment in the embodiment.

[0030] Figure 3 Schematic diagram of the structure of the partition in the embodiment.

[0031] Figure 4 Schematic diagram of the internal structure of the equipment for extracting lithium from the positive black powder of the lithium iron phosphate battery in the embodiment.

[0032] Figure 5 yes Figure 4 A partial enlarged view of B.

[0033] Figure 6 Schematic diagram of the structure of the warehouse body in the embodiment.

[0034] Figure 7 2 is a schematic structural diagram of the connecting base in the embodiment.

[0035] Figure 8 Schematic diagram of the structure of the water supply pipe in the embodiment.

[0036] Figure 9 yes Figure 2 A partial enlarged view of middle A.

[0037] Description of reference numerals: 1. Leaching mechanism; 11. Slurry mixing tank; 12. Leaching tank; 13. Plate and frame compressor; 2. Evaporation and concentration device; 3. Lithium precipitation device; 31. Lithium precipitation tank; 32. Centrifuge; 33. Slurry mixing tank; 4. Demagnetization tank; 5. Demagnetization assembly; 51. Demagnetization unit; 511. Mounting seat; 5111. Dispersion chamber; 5112. Water outlet; 512. Demagnetization member; 513. Sealing plate; 514. Elastic member; 52. Partition; 53. Chamber; 531. First temporary storage chamber; 532. Second temporary storage chamber; 533. Filter; 534. Demagnetization chamber; 535. Chamber to be cleaned; 536. Cleaning chamber; 537. Chamber to be demagnetized; 54. First rotating shaft; 55. Accommodating chamber; 6. Cleaning assembly; 61. Water storage tank; 62. Connecting tube; 63. Water supply pipe; 631. Rubber tube; 632. Abutment ring; 633. Threaded strip; 64. Water supply hose; 65. Water baffle; 66. Second rotating shaft; 67. Circular baffle; 68. Coil spring; 7. Filter tank; 8. Heating tank; 9. Drive assembly; 91. Third rotating shaft; 911. Spiral plate; 92. Remaining gear; 93. First gear; 94. Second gear. DETAILED DESCRIPTION

[0038] The following is combined with Figure 1-9 This application is described in further detail.

[0039] The present application embodiment discloses a lithium iron phosphate battery positive electrode black powder lithium extraction equipment. Figure 1-3 The lithium iron phosphate battery positive electrode black powder lithium extraction equipment includes a leaching mechanism 1, an evaporation concentration device 2, a lithium precipitation device 3, a demagnetization tank 4, a demagnetization component 5, a cleaning component 6, a filter tank 7 and a heating tank 8; the leaching mechanism 1 includes a slurry mixing tank 11, a leaching tank 12 and a plate and frame compressor 13; the slurry mixing tank 11, the leaching tank 12 and the plate and frame compressor 13 are connected by pipelines; the leaching mechanism 1 is used to acid-leach the black powder and prepare an acid leaching solution; the evaporation concentration device 2 is connected to the leaching mechanism 1; the evaporation concentration device 2 is used to evaporate and concentrate the acid leaching solution; the lithium precipitation device 3 includes a lithium precipitation tank 31, a centrifuge 32 and a slurry mixing tank 33; the lithium precipitation tank 31 is connected to the evaporation concentration device 2, the centrifuge 32 and the slurry mixing tank 33 through a pipeline The core machine 32 is connected to the slurry mixing tank 33; the demagnetization tank 4 is connected to the slurry mixing tank 33; the demagnetization component 5 is rotatably set on the demagnetization tank 4; the demagnetization component 5 has a accommodating chamber 55; the accommodating chamber 55 is communicated with the inside of the demagnetization tank 4; four demagnetization parts 51 are provided in the accommodating chamber 55; partitions 52 are provided between adjacent demagnetization parts 51; the four partitions 52 divide the accommodating chamber 55 into a demagnetization chamber 534, a chamber to be cleaned 536, a cleaning chamber 536 and a chamber to be demagnetized 537; the cleaning component 6 is set on the demagnetization tank 4 and corresponds to the cleaning chamber 536; the cleaning component 6 is used to clean the demagnetization part 51 in the cleaning chamber 536; the filter tank 7 is connected to the demagnetization tank 4; the heating tank 8 is connected to the filter tank 7.

[0040] In order to improve the demagnetization efficiency, multiple groups of demagnetization components 5 and cleaning components 6 can be provided; in order to prevent the drawings from being disordered, only one group of demagnetization components 5 and cleaning components 6 is drawn in the drawings.

[0041] Reference Figures 3 to 6 The demagnetization component 5 includes a warehouse body 53, a first rotating shaft 54 ​​and a demagnetization part 51; the warehouse body 53 is arranged on the outer wall of the demagnetization tank 4 and is connected to the interior of the demagnetization tank 4; the four partitions 52 on the first rotating shaft 54 ​​divide the interior of the warehouse body 53 into a demagnetization chamber 534, a chamber to be cleaned 536, a cleaning chamber 536 and a chamber to be demagnetized 537; the four demagnetization parts 51 are respectively located in the demagnetization chamber 534, the chamber to be cleaned 536, the cleaning chamber 536 and the chamber to be demagnetized 537; the bottom of the warehouse body 53 has a first temporary storage chamber 531 and a second temporary storage chamber 532; the first temporary storage chamber 531 is located directly below the chamber to be cleaned 536; the second temporary storage chamber 532 is located directly below the cleaning chamber 536; the first rotating shaft 54 ​​is rotatably set on the demagnetization tank 4 and passes through the warehouse body 53; the four demagnetization parts 51 are evenly arranged on the first rotating shaft 54 ​​along the circumference; the four partitions 52 are evenly arranged on the first rotating shaft 54 ​​along the circumference.

[0042] It should be noted that due to the continuous rotation of the first rotating shaft 54, the four partitions 52 also rotate continuously following the first rotating shaft 54, so that the positions of the four chambers separated by the partitions 52 are continuously changed; after the first rotating shaft 54 ​​is rotated, the chamber located in the demagnetization tank 4 is defined as the demagnetization chamber 534, the chamber located at the outside of the cleaning component 6 is defined as the cleaning chamber 536, and the other two chambers are respectively defined as the chamber to be cleaned 536 and the chamber to be demagnetized 537.

[0043] Specifically, the demagnetization part 51 includes a mounting seat 511, multiple demagnetization parts 512, two sealing plates 513 and two elastic parts 514; the mounting seat 511 is a fan-shaped plate; four mounting seats 511 are evenly arranged on the first rotating shaft 54 ​​along the circumference; the four mounting seats 511 are assembled together to form a cylindrical plate; a plurality of water outlet holes 5112 are provided at the bottom of the mounting seat 511; a dispersion cavity 5111 connected to the multiple water outlet holes 5112 is provided in the mounting seat 511; a water inlet is provided at the top of the mounting seat 511; the water inlet is connected to the dispersion cavity 5111; multiple demagnetization parts 512 are arranged on the mounting seat 511 and are located between the multiple water outlet holes 5112; it is convenient for the water sprayed from the multiple water outlet holes 5112 to flush various parts of the demagnetization part 512; the demagnetization part 512 is an electromagnetic rod, and when the cleaning component 6 is working, the demagnetization part 512 is powered off. Two sealing plates 513 slide relative to each other on either side of the water inlet, sealing the water inlet. The tops of the sealing plates 513 have curved guide surfaces. After the cleaning assembly 6 moves downward, the bottom of the water supply pipe 63 contacts the two curved guide surfaces, pushing the two sealing plates 513 apart and allowing the water supply pipe 63 to be inserted into the water inlet. Two elastic members 514 are provided corresponding to the two sealing plates 513. For example, one end of the elastic member 514 is connected to the mounting seat 511, and the other end is connected to the sealing plate 513. The two elastic members 514 are used to push the two sealing plates 513 into contact with each other, allowing the cleaning assembly 6 to be released from the mounting seat 511, allowing the two sealing plates 513 to reseal the water inlet.

[0044] Reference Figure 4 、 Figure 5 、 Figure 7 and Figure 8The cleaning assembly 6 includes a water storage tank 61, a connecting tube 62, a water supply pipe 63, a water supply hose 64, a water supply pump, a water baffle 65, a second rotating shaft 66, a circular baffle 67 and a coil spring 68; the water storage tank 61 is arranged on the demagnetization tank 4; the connecting tube 62 is rotatably arranged on the demagnetization tank 4; the inner wall of the connecting tube 62 is intermittently provided with four groups of internal threads; the four groups of internal threads are evenly distributed along the circumference of the connecting tube 62; a falling channel is formed between adjacent internal threads; it is vertically slidable in the connecting tube 62; the outer wall of the water supply pipe 63 is intermittently provided with four groups of thread strips 633; ​​four groups of thread strips 633 respectively cooperate with four groups of internal threads; the width of the four groups of thread strips 633 is the same as the width of the falling channel; after the thread strips 633 are disengaged from the internal threads, the thread strips 633 can move downward along the falling channel; the bottom of the water supply pipe 63 is connected to the water inlet; one end of the water supply hose 64 is connected to the water storage tank 61, and the other end is connected to the top of the water supply pipe 63; the water supply pump is arranged in the water storage tank 61; the water supply pump is connected to the water supply hose 64, and the water supply pump can pressurize the water in the water storage tank 61 and fill it into the mounting seat 511 through the water supply hose 64 and the water supply pipe 63. The water baffle 65 is a semicircular plate, which is arranged in the water supply pipe 63, narrowing the outlet of the water supply pipe 63, thereby enhancing the water pressure; the second rotating shaft 66 is rotatably arranged in the water supply pipe 63; the middle part of the circular baffle 67 is fixed on the second rotating shaft 66; the peripheral side wall of the circular baffle 67 abuts against the inner wall of the water supply pipe 63; the coil spring 68 is wound on the second rotating shaft 66; one end of the coil spring 68 is connected to the second rotating shaft 66, and the other end is connected to the water supply pipe 63; a rubber tube 631 is connected to the bottom of the water supply pipe 63; an abutment ring 632 is connected to the bottom of the rubber tube 631; the abutment ring 632 abuts against the two arc-shaped guide surfaces.

[0045] A water pump is provided in the first temporary storage chamber 531 and the second temporary storage chamber 532 respectively. The two water pumps pump the lithium carbonate slurry in the first temporary storage chamber 531 and the water in the second temporary storage chamber 532 into the demagnetization tank 4 and the water storage tank 61 respectively; a filter screen 533 is provided in the second temporary storage chamber 532. The filter screen 533 can filter out magnetic substances to keep the water source in the water storage tank 61 clean.

[0046] Reference Figure 1 、 Figure 4 and Figure 9The driving assembly 9 includes a third rotating shaft 91, a residual gear 92, a first gear 93 and a second gear 94; the third rotating shaft 91 is coaxially arranged in the demagnetization tank 4; a motor is arranged on the demagnetization tube, and the power output end of the motor is coaxially connected to the third rotating shaft 91, which can drive the third rotating shaft 91 to rotate; a spiral plate 911 is arranged on the circumference of the third rotating shaft 91; the spiral plate 911 is located in the demagnetization tank 4; the residual gear 92 is coaxially fixed on the third rotating shaft 91; the first gear 93 is coaxially fixed on the first rotating shaft 54; the first gear 93 is meshed with the residual gear 92; the second gear 94 is coaxially fixed on the connecting tube 62; the second gear 94 is meshed with the first gear 93. When the residual gear 92 drives the first gear 93 to rotate, it only drives the first gear 93 to rotate ninety degrees, ensuring that the four demagnetization parts 51 can stably exchange positions.

[0047] The working principle of a lithium iron phosphate battery positive electrode black powder lithium extraction device in this application is: After the black powder is made into lithium carbonate slurry through the leaching mechanism 1, the evaporation concentration device 2 and the lithium precipitation device 3, it is introduced into the demagnetization tank 4; then the motor is started to drive the third rotating shaft 91 to rotate, and the spiral plate 911 in the demagnetization tank 4 stirs the lithium carbonate slurry upward, so that the lithium carbonate slurry moves toward the side wall of the demagnetization tank 4; at the same time, the residual gear 92 rotates, and drives the first gear 93 and the second gear 94 to respectively drive the first rotating shaft 54 ​​and the connecting cylinder 62 to rotate; after the first rotating shaft 54 ​​rotates, the mounting seat 511 and the demagnetization part 51 thereunder are rotated ninety degrees; during the rotation of the first rotating shaft 54, the lithium carbonate slurry in the demagnetization tank 4 enters the chamber to be demagnetized 537 and the chamber to be cleaned 536; The lithium carbonate slurry in the cleaning chamber 536 enters the first temporary storage chamber 531; the lithium carbonate slurry in the demagnetization chamber 537 is pushed back into the demagnetization tank 4 by the partition 52; the connecting tube 62 rotates and drives the water supply pipe 63 to move upward. When the connecting tube 62 rotates ninety degrees, the threaded bar 633 enters the falling channel, the connection between the connecting tube 62 and the water supply pipe 63 is lost, and the water supply pipe 63 moves downward; when the water supply pipe 63 moves downward, the abutment ring 632 at its bottom squeezes the two guide arc surfaces, pushing the two sealing plates 513 away from each other, so that the water supply pipe 63 extends into the water inlet; after the water supply pipe 63 moves upward, the two sealing plates 513 abut against each other under the push of the two elastic members 514.

[0048] When the cleaning component 6 is working, the water supply pump is started to pressurize the water in the water storage tank 61, and then the pressurized water is passed into the mounting seat 511 through the water supply hose 64 and the water supply pipe 63; the pressurized water is briefly stored in the dispersion chamber 5111, and then flows to each water outlet hole 5112, flushing the magnetic material on each demagnetization component 512 into the second temporary storage chamber 532.

[0049] When the pressurized water passes through the water supply pipe 63, it is pressurized by the water baffle 65 and impacts one side of the circular baffle 67, causing the circular baffle 67 to rotate, thereby allowing the water to continue to flow downstream; after the water supply pump is turned off, the second rotating shaft 66 is reset under the action of the coil spring 68, and drives the circular baffle 67 to reset, re-blocking the water supply pipe 63.

[0050] The present application also discloses a method for extracting lithium from black powder of the positive electrode of a lithium iron phosphate battery, comprising an oxidative acid leaching process, a lithium concentration and purification process, a lithium precipitation process, a carbonization and thermal decomposition process of lithium carbonate, and a centrifugal drying process. During the oxidative acid leaching process, black powder and water are added to a slurry mixing tank 11 and stirred, and the mixture of black powder and water is added to a leaching tank 12 through a pipeline; concentrated sulfuric acid and hydrogen peroxide are introduced into the leaching tank 12 for acid leaching to obtain a leachate; the leachate is sent to a plate and frame filter press through a pipeline for solid-liquid separation to obtain a filtrate; During the lithium concentration and purification process, the filtrate is passed into the filter tank 7 for impurity removal and filtration, and then passed into the evaporation concentration device 2 to evaporate excess water and obtain a concentrated solution; During the lithium precipitation process, the concentrated liquid is pumped into the lithium precipitation tank 31 through a pipeline, and sodium carbonate solution is added in proportion to carry out lithium precipitation reaction; after the reaction is complete, it is passed into the centrifuge 32 for separation to obtain lithium carbonate solid; During the carbonization and thermal decomposition process of lithium carbonate, solid lithium carbonate is added to a slurry mixing tank 33 and stirred with water, and then carbon dioxide gas is introduced to perform a carbonization reaction. After the carbonization is completed, the solid lithium carbonate is introduced into a demagnetization tank 4 and a filter tank 7 for filtering and removing impurities, and then introduced into a heating tank 8 for thermal decomposition to obtain a lithium carbonate slurry. During the centrifugal drying process, the lithium carbonate slurry is passed into the centrifuge 32 for solid-liquid separation, and the separated lithium carbonate solid is dried, screened, iron-removed, crushed and packaged to obtain high-purity battery-grade lithium carbonate.

[0051] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A lithium iron phosphate battery cathode black powder lithium extraction equipment, characterized in that, include: Leaching mechanism (1); the leaching mechanism (1) is used for acid leaching the black powder and preparing an acid leaching solution; An evaporation and concentration device (2) is connected to the leaching mechanism (1); the evaporation and concentration device (2) is used to evaporate and concentrate the acid leaching solution; A lithium precipitation device (3) is connected to the evaporation concentration device (2); a demagnetization tank (4) connected to the lithium precipitation device (3); A demagnetization component (5) is rotatably mounted on the demagnetization tank (4); the demagnetization component (5) has a receiving chamber (55); the receiving chamber (55) is communicated with the interior of the demagnetization tank (4); four demagnetization parts (51) are provided in the receiving chamber (55); partitions (52) are provided between adjacent demagnetization parts (51); the four partitions (52) divide the receiving chamber (55) into a demagnetization chamber (534), a chamber to be cleaned (536), a cleaning chamber (536), and a chamber to be demagnetized (537); A cleaning assembly (6) is provided on the demagnetization tank (4) and corresponds to the cleaning chamber (536); the cleaning assembly (6) is used to clean the demagnetization portion (51) in the cleaning chamber (536); A filter tank (7) connected to the demagnetization tank (4); The heating tank (8) is connected to the filter tank (7).

2. The lithium iron phosphate battery positive electrode black powder lithium extraction equipment according to claim 1, characterized in that, The demagnetization component (5) comprises: A silo (53) is provided on the outer wall of the demagnetization tank (4) and is in communication with the interior of the demagnetization tank (4); the four demagnetization parts (51) are located in the silo (53); the bottom of the silo (53) is provided with a first temporary storage chamber (531) and a second temporary storage chamber (532); the first temporary storage chamber (531) is located directly below the chamber to be cleaned (536); the second temporary storage chamber (532) is located directly below the cleaning chamber (536); A first rotating shaft (54) is rotatably arranged on the demagnetization tank (4) and passes through the warehouse body (53); the four demagnetization parts (51) are evenly arranged on the first rotating shaft (54) along the circumferential direction; and the four partitions (52) are evenly arranged on the first rotating shaft (54) along the circumferential direction.

3. The lithium iron phosphate battery positive electrode black powder lithium extraction equipment according to claim 2, characterized in that, The demagnetization unit (51) includes: A mounting seat (511), wherein four mounting seats (511) are evenly arranged on the first rotating shaft (54) along the circumferential direction; a plurality of water outlet holes (5112) are provided at the bottom of the mounting seat (511); a dispersion cavity (5111) is provided in the mounting seat (511) and is communicated with the plurality of water outlet holes (5112); a water inlet is provided at the top of the mounting seat (511); the water inlet is communicated with the dispersion cavity (5111); A plurality of demagnetizing components (512) are arranged on the mounting seat (511); the plurality of demagnetizing components (512) are located between the plurality of water outlet holes (5112); The cleaning component (6) has elastic freedom to slide vertically; the cleaning component (6) has a water supply port; the water supply port is connected to or disconnected from the water inlet.

4. The lithium iron phosphate battery positive electrode black powder lithium extraction equipment according to claim 3, characterized in that, The cleaning assembly (6) comprises: A water storage tank (61) is provided on the demagnetization tank (4); A connecting cylinder (62) is rotatably mounted on the demagnetization tank (4); four groups of internal threads are intermittently provided on the inner wall of the connecting cylinder (62); the four groups of internal threads are evenly distributed along the circumference of the connecting cylinder (62); and a falling channel is formed between adjacent internal threads; A water supply pipe (63) is vertically slidably disposed in the connecting tube (62); four groups of threaded strips (633) are intermittently provided on the outer wall of the water supply pipe (63); the four groups of threaded strips (633) respectively cooperate with the four groups of internal threads; the bottom of the water supply pipe (63) is connected to or disconnected from the water inlet; A water supply hose (64), one end of which is connected to the water storage tank (61) and the other end of which is connected to the top of the water supply pipe (63); A water supply pump is arranged in the water storage tank (61); the water supply pump is connected to the water supply hose (64).

5. The lithium iron phosphate battery positive electrode black powder lithium extraction equipment according to claim 4, characterized in that, The lithium iron phosphate battery positive electrode black powder lithium extraction device further includes a driving component (9); the driving component (9) includes: A third rotating shaft (91) is coaxially rotatably disposed in the demagnetization tank (4); a spiral plate (911) is disposed on a circumferential side of the third rotating shaft (91); A residual gear (92) is coaxially fixed on the third rotating shaft (91); A first gear (93) is coaxially fixed on the first rotating shaft (54); the first gear (93) is meshed with the residual gear (92); The second gear (94) is coaxially fixed on the connecting cylinder (62); the second gear (94) is meshed with the first gear (93).

6. The lithium iron phosphate battery positive electrode black powder lithium extraction equipment according to claim 4, characterized in that, The demagnetization unit (51) further includes: Two sealing plates (513) are relatively slidably arranged on both sides of the water inlet; the top of the sealing plate (513) has an arc-shaped guide surface; the bottom of the water supply pipe (63) abuts against the two arc-shaped guide surfaces; Two elastic members (514); one end of the two elastic members (514) is respectively arranged on the two sealing plates (513); the other ends of the two elastic members (514) are respectively connected to the mounting seats (511); the two elastic members (514) are respectively used to push the two sealing plates (513) to abut against each other.

7. The lithium iron phosphate battery positive electrode black powder lithium extraction equipment according to claim 6, characterized in that: The bottom of the water supply pipe (63) is connected to a rubber tube (631); the bottom of the rubber tube (631) is connected to an abutment ring (632); the abutment ring (632) abuts against the two arc-shaped guide surfaces.

8. The lithium iron phosphate battery positive electrode black powder lithium extraction equipment according to claim 4, characterized in that: The cleaning component (6) further comprises: a water baffle (65) disposed in the water supply pipe (63); a second rotating shaft (66) rotatably disposed in the water supply pipe (63); A circular baffle (67) is provided on the second rotating shaft (66); the circumference of the circular baffle (67) abuts against the inner wall of the water supply pipe (63); A coil spring (68) is wound around the second rotating shaft (66); one end of the coil spring (68) is connected to the second rotating shaft (66), and the other end is connected to the water supply pipe (63).

9. The lithium iron phosphate battery cathode black powder lithium extraction equipment according to claim 1, characterized in that: The leaching mechanism (1) comprises a slurry mixing tank (11), a leaching tank (12) and a plate-frame compressor (13); the slurry mixing tank (11), the leaching tank (12) and the plate-frame compressor (13) are connected via a pipeline; the lithium precipitation device (3) comprises a lithium precipitation tank (31), a centrifuge (32) and a slurry mixing tank (33); the lithium precipitation tank (31) is connected to the evaporation concentration device (2), the centrifuge (32) and the slurry mixing tank (33) via the pipeline.

10. A method for extracting lithium from positive electrode black powder of lithium iron phosphate battery, characterized in that: The lithium iron phosphate battery positive electrode black powder lithium extraction device according to any one of claims 1 to 9 is used to extract lithium from the lithium iron phosphate battery positive electrode black powder; the lithium iron phosphate battery positive electrode black powder lithium extraction method comprises: Step S1: adding black powder and water into the slurry mixing tank (11) and stirring, and adding the mixture of black powder and water into the leaching tank (12) through the pipeline; introducing concentrated sulfuric acid and hydrogen peroxide into the leaching tank (12) for acid leaching to obtain a leachate; sending the leachate into the plate and frame filter press through the pipeline for solid-liquid separation, and obtaining a filtrate; Step S2: passing the filtrate into a filter tank (7) for impurity removal and filtration, and then passing it into the evaporation and concentration device (2) to evaporate excess water and obtain a concentrated solution; Step S3: pumping the concentrated liquid into the lithium precipitation tank (31) through a pipeline, adding sodium carbonate solution in proportion to carry out lithium precipitation reaction; after the reaction is complete, passing it into a centrifuge (32) for separation to obtain lithium carbonate solid; Step S4: adding the lithium carbonate solid into a slurry mixing tank (33) and adding water to stir, then introducing carbon dioxide gas to carry out carbonization reaction, and after carbonization is completed, passing the solid into the demagnetization tank (4) and the filter tank (7) in sequence to filter and remove impurities, and then passing the solid into the heating tank (8) to heat and decompose, thereby obtaining a lithium carbonate slurry; Step S5: passing the lithium carbonate slurry into a centrifuge (32) for solid-liquid separation, and drying, screening, iron removal, crushing and packaging the separated lithium carbonate solid to obtain high-purity battery-grade lithium carbonate.

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