Equipment and process method for preparing lithium battery positive electrode material from lithium precipitation mother liquor

Abstract

The invention provides equipment and a process method for preparing a lithium battery positive electrode material from lithium precipitation mother liquor, and relates to the technical field of lithium phosphate preparation, the equipment comprises a reaction tank, a moving mechanism, a crystal removal mechanism and a vibration desorption mechanism; the moving mechanism comprises a reciprocating belt and a reciprocating frame, the reciprocating frame is fixedly arranged on the surface of the reciprocating belt, and the reciprocating belt rotates to drive the reciprocating frame to reciprocate in the reaction tank. According to the scheme, when a reciprocating belt drives a reciprocating frame to move, under the cooperation of a crystal removing toothed plate and a rotating gear, a cleaning brush can rotate, so that lithium phosphate fine crystals adsorbed on the inner wall of the reaction tank are swept and stripped, and the fine crystals can be efficiently stripped by utilizing the reciprocating rotation of the cleaning brush; according to the method, the lithium phosphate enters an extraction system again, so that the total recovery rate of the lithium phosphate is improved, and for high-purity and high-value battery-grade lithium phosphate, the raw material loss can be remarkably reduced, and the production cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium phosphate preparation, and particularly relates to a lithium precipitation mother liquor preparation equipment for lithium battery positive electrode materials and a process method. BACKGROUND

[0002] The lithium precipitation mother liquor is a lithium-containing waste liquid generated in the production process of lithium salt. High-purity lithium phosphate can be recovered from the waste liquid through a reasonable process. Lithium phosphate is a colorless rhombic crystal or white crystalline substance, and has unique electrochemical properties. The mainstream positive electrode material prepared by taking lithium phosphate as a precursor is mainly a phosphate system. Such material is widely used in the field of lithium batteries for automobiles due to high safety and long cycle life.

[0003] In the related art, high-purity lithium phosphate can be recovered from the lithium precipitation mother liquor to prepare the positive electrode material of the lithium battery for automobiles. In the process of recovering lithium phosphate from the lithium precipitation mother liquor, the fine lithium phosphate crystals have negative charges and are adsorbed on the inner wall of the metal reaction tank. The existing preparation equipment is not convenient for processing the fine lithium phosphate crystals adsorbed on the inner wall of the reaction tank. The fine lithium phosphate crystals are retained on the inner wall of the reaction tank, which directly leads to a decrease in the recovery rate of lithium phosphate. In addition, the crystals randomly peeled off during the preparation process are mixed into the new batch, which causes the purity of the lithium phosphate product to fluctuate and cannot meet the requirements of the positive electrode material of the lithium battery.

[0004] Therefore, it is necessary to provide a lithium precipitation mother liquor preparation equipment for lithium battery positive electrode materials to solve the above technical problems. SUMMARY

[0005] The present application provides a lithium precipitation mother liquor preparation equipment for lithium battery positive electrode materials, which solves the technical problem that the existing preparation equipment in the related art is not convenient for processing the fine lithium phosphate crystals adsorbed on the inner wall of the reaction tank.

[0006] To solve the above technical problems, the lithium precipitation mother liquor preparation equipment for lithium battery positive electrode materials provided by the present application comprises a reaction tank, a moving mechanism, a crystal removal mechanism and a vibration desorption mechanism. The moving mechanism comprises a reciprocating belt and a reciprocating frame, the reciprocating frame is fixed to the surface of the reciprocating belt, and the reciprocating frame can be driven to reciprocate in the reaction tank through the rotation of the reciprocating belt. The crystal removal mechanism comprises two sliding blocks slidingly connected to the inner side of the reciprocating frame, two cleaning brushes are vertically rotatably connected to the inner side of each of the two sliding blocks, rotating gears are fixed to the top surface of each of the two cleaning brushes, crystal removal tooth plates are fixed to the front side and the rear side of the inner wall of the reaction tank, and the two crystal removal tooth plates are meshed with the two rotating gears, respectively. The vibration desorption mechanism comprises two adjusting screws screwed into the inner sides of the two sliders, the top ends of the two adjusting screws are rotationally connected with contact wheels, the inner sides of the reciprocating frame and located on the opposite sides of the two sliders are provided with springs, and the front side and the rear side of the inner wall of the reaction tank are fixedly provided with vibration plates.

[0007] Preferably, the surface of the vibration plate is a concave-convex structure, and when the contact wheel contacts and walks along the vibration plate, the slider can slide back and forth in the inner side of the reciprocating frame through the cooperation of the spring.

[0008] Preferably, the two sides of the inner wall of the reaction tank are fixedly provided with mounting brackets, the inner sides of the two mounting brackets are rotationally connected with driving wheels, the reciprocating belt is sleeved on the surfaces of the two driving wheels, the bottom of the reciprocating frame is slidingly connected with two guide seats, the two ends of the two guide seats are fixedly connected with the inner wall of the reaction tank, the left side of the reaction tank is provided with a driving motor, the output end of the driving motor and the front end of the left driving wheel are fixedly provided with bevel gears, and the two bevel gears are meshed with each other.

[0009] Preferably, the left side of the inner wall of the reaction tank is fixedly provided with a monitoring mechanism, the monitoring mechanism comprises a rotating seat fixedly provided on the left side of the inner wall of the reaction tank, the inner side of the rotating seat is rotationally connected with an industrial camera through a rotating shaft, the industrial camera is fixedly provided with an adjusting gear through the rotating shaft, and the front side of the bottom of the reciprocating frame is fixedly provided with a driving gear plate.

[0010] Preferably, the left side of the inner wall of the reaction tank is fixedly provided with a detection mechanism, the detection mechanism comprises a mounting plate fixedly provided on the left side of the inner wall of the reaction tank, the right side of the mounting plate is fixedly provided with two threaded guide rods, the surfaces of the two threaded guide rods are slidingly connected with moving blocks, the inner sides of the moving blocks are rotationally connected with a follow-up frame, the inner side of the mounting plate is provided with a slot, the rear side of the follow-up frame is located in the slot, the follow-up frame is internally provided with a PH detector, the inside of the reciprocating frame is threadedly connected with a trigger rod, and the surfaces of the two threaded guide rods are sleeved with return springs.

[0011] Preferably, the top of the reciprocating frame is provided with a PH adjusting mechanism, the PH adjusting mechanism comprises a solution tank arranged on the top of the reciprocating frame, a pipeline is rotationally connected in the reciprocating frame in the longitudinal direction, a plurality of spray heads are communicated on the surface of the pipeline, two reversing gears are fixedly arranged on the surface of the pipeline, reversing gear plates are fixedly arranged on the front side and the rear side of the two mounting brackets, a water pump is arranged on the front side of the top of the reciprocating frame, and the water pump is communicated with the solution tank and the pipeline through a hose.

[0012] Preferably, the inner wall of the reaction tank is transversely connected with a mixing mechanism, the mixing mechanism comprises a mixing shaft transversely connected with the inner wall of the reaction tank, the surface of the mixing shaft is provided with a plurality of mixing frames, and the right side of the reaction tank is provided with a mixing motor for driving the mixing shaft to rotate.

[0013] Preferably, the two ends of the mixing shaft are both fixed with two arc-shaped plates through bolts, the inner side of the arc-shaped plate is provided with a through groove, the surface of the four arc-shaped plates is fixed with a scraping plate, the bottom of the reaction tank is provided with two collecting grooves, and the surface of the two collecting grooves is communicated with a liquid discharge pipe.

[0014] A process method for preparing lithium battery positive electrode material from lithium precipitation mother liquor, comprising the following steps: Step S1: uniformly mix the lithium precipitation mother liquor and concentrated sulfuric acid in proportion, control the PH to be neutral, and remove the carbonate to obtain a decarbonized liquid; Step S2: preheat the obtained decarbonized liquid to a suitable temperature, and then perform MVR evaporation concentration to obtain a concentrated liquid; Step S3: centrifugal filtration of the obtained concentrated liquid to obtain a sodium-potassium mixture and a concentrated filtrate; Step S4: cooling the obtained concentrated filtrate to a suitable temperature to crystallize and filter to obtain Na2SO4·H2O and a frozen filtrate, and dehydrating and drying to obtain sodium sulfate; Step S5: MVR evaporator concentration of the frozen filtrate to a suitable concentration to obtain a concentrated liquid; + to a suitable concentration to obtain a concentrated liquid; Step S6: prepare di(2-ethylhexyl) phosphate-sulfonated kerosene (volume ratio 1:3) as an extractant, add 5% tributyl phosphate as a co-extractant, extract the concentrated liquid in a certain proportion, control the PH in a suitable range, and perform three times of countercurrent washing to obtain an extract liquid; Step S7: back extraction of the obtained extract liquid with a phosphoric acid solution of a suitable concentration to obtain a LiH2PO4 solution, and adjust the PH to alkaline to generate Li3PO4.

[0015] Compared with the related art, the equipment and process method for preparing lithium battery positive electrode material from lithium precipitation mother liquor have the following beneficial effects: When the reciprocating belt drives the reciprocating frame to move, the cleaning brush rotates in conjunction with the crystal removal tooth plate and the rotating gear. This sweeps and peels off the fine lithium phosphate crystals adsorbed on the inner wall of the reaction tank. The reciprocating rotation of the cleaning brush can efficiently peel off these fine crystals, allowing them to re-enter the extraction system, thereby improving the overall recovery rate of lithium phosphate. For high-purity, high-value battery-grade lithium phosphate, this can significantly reduce raw material loss and lower production costs. Furthermore, the timely removal by the brush can prevent crystals from accumulating on the tank wall for a long time, reduce the interference of detachment on the uniformity of the reaction solution, ensure the stability of the lithium phosphate crystallization process, and indirectly improve the purity and consistency of the final product. When the reciprocating belt moves the reciprocating frame to the right and continues to move to the right, the contact wheel and the vibrating plate work together to make the slider move the cleaning brush back and forth. Combined with the reaction liquid, the crystals attached to the surface can be shaken off in time, preventing fine lithium phosphate crystals from adhering to or accumulating on the brush bristles. It has a self-cleaning function, which can effectively prevent the cleaning brush from deteriorating due to oxidation and adsorption of impurities in the reaction system, thus affecting the precision of lithium phosphate products. It ensures that the brush always remains clean and continuously and efficiently peels off the crystals from the tank wall. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 The optimal structural schematic diagram provided for this invention; Figure 2 This is a schematic diagram of the structure of the reaction tank (right view) provided by the present invention. Figure 3 A schematic diagram of the structure of the moving mechanism provided by the present invention; Figure 4 This is a schematic diagram of the structure of the crystal removal mechanism and the vibration desorption mechanism provided by the present invention; Figure 5 for Figure 4 The enlarged structural diagram at point A is shown below; Figure 6 A schematic diagram showing the state in which the reset frame provided by the present invention moves to the right and the contact wheel contacts the vibration plate; Figure 7 This is a schematic diagram of the monitoring mechanism provided by the present invention; Figure 8 A schematic diagram showing the state in which the reset frame provided by the present invention moves to the left, and the driving gear plate drives the adjusting gear to rotate. Figure 9 Structure diagram of detection mechanism provided by the present application; Figure 10 Structure diagram of detection mechanism provided by the present application; Figure 9 Structure diagram of detection mechanism provided by the present application; Figure 11 Structure diagram of PH adjusting mechanism provided by the present application; Figure 12 Structure diagram of detection mechanism provided by the present application; Figure 13 Structure diagram of detection mechanism provided by the present application; Figure 14 Structure diagram of detection mechanism provided by the present application; Figure 13 Structure diagram of detection mechanism provided by the present application; Figure 15 Process flow diagram of process method provided by the present application.

[0018] Explanation of reference numerals: 1. Reaction tank 2. Moving mechanism; 21. Reciprocating belt; 22. Reciprocating frame; 23. Mounting bracket; 24. Driving wheel; 25. Guide seat; 26. Driving motor; 27. Bevel gear 3. Crystal removing mechanism; 31. Slide block; 32. Cleaning brush; 33. Rotating gear; 34. Crystal removing gear plate 4. Vibration desorption mechanism; 41. Adjusting screw; 42. Contact wheel; 43. Spring; 44. Vibration plate 5. Monitoring mechanism; 51. Rotating seat; 52. Industrial camera; 53. Adjusting gear; 54. Driving gear plate 6. Detection mechanism; 61. Mounting plate; 62. Threaded guide rod; 63. Moving block; 64. Follow-up frame; 65. Notch; 66. PH detector; 67. Trigger rod; 68. Reset spring 7. PH adjusting mechanism; 71. Solution tank; 72. Pipeline; 73. Spray head; 74. Inverting gear; 75. Inverting gear plate; 76. Water pump 8. Mixing mechanism; 81. Mixing shaft; 82. Mixing frame; 83. Mixing motor 9. Arc-shaped plate; 10. Scraping plate; 11. Collection groove; 12. Drain pipe

[0019] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0020] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0021] The application provides a device and a process method for preparing lithium battery positive electrode materials from a lithium precipitation mother liquor.

[0022] First embodiment: Please refer to Figures 1 to 6 A device for preparing lithium battery positive electrode materials from a lithium precipitation mother liquor, comprising a reaction tank 1, a moving mechanism 2, a crystal removal mechanism 3 and a vibration desorption mechanism 4. Preferably, the reaction tank 1 has a heating and temperature adjusting function for controlling the reaction temperature. The moving mechanism 2 comprises a reciprocating belt 21 and a reciprocating frame 22, the reciprocating frame 22 is fixedly arranged on the surface of the reciprocating belt 21, and the reciprocating frame 22 can be driven to move reciprocally in the reaction tank 1 by rotating the reciprocating belt 21. Both sides of the inner wall of the reaction tank 1 are fixedly provided with mounting brackets 23, both inner sides of the two mounting brackets 23 are rotatably connected with driving wheels 24, the reciprocating belt 21 is sleeved on the surfaces of the two driving wheels 24, the bottom of the reciprocating frame 22 is slidably connected with two guide seats 25, both ends of the two guide seats 25 are fixedly connected with the inner wall of the reaction tank 1, the left side of the reaction tank 1 is provided with a driving motor 26, the output end of the driving motor 26 and the front end of the left driving wheel 24 are fixedly provided with bevel gears 27, and the two bevel gears 27 are meshed with each other. Please refer to Figure 3 : Start the driving motor 26, rotate the driving motor 26 to drive the left driving wheel 24 to rotate through the two bevel gears 27, rotate the left driving wheel 24 to drive the reciprocating belt 21 to rotate, rotate the reciprocating belt 21 to drive the reciprocating frame 22 to move, and control the rotating direction of the driving motor 26 to drive the reciprocating belt 21 to move reciprocally left and right with the reciprocating frame 22. Preferably, the two guide seats 25 are arranged to enable the reciprocating frame 22 to move stably left and right. The crystal removal mechanism 3 comprises two sliding blocks 31 slidably connected to the inner side of the reciprocating frame 22, the inner sides of the two sliding blocks 31 are perpendicularly rotatably connected with cleaning brushes 32, the surfaces of the top portions of the two cleaning brushes 32 are fixedly provided with rotating gears 33, the front side and the rear side of the inner wall of the reaction tank 1 are fixedly provided with crystal removal tooth plates 34, and the two crystal removal tooth plates 34 are respectively meshed with the two rotating gears 33. Please refer to Figure 4 andFigure 5 When the reciprocating belt 21 drives the reciprocating frame 22 to move, the reciprocating frame 22 drives the cleaning brush 32 and the rotating gear 33 to move at the same time, and under the cooperation of the crystal removing gear plate 34 and the rotating gear 33, the cleaning brush 32 rotates during the movement, thereby sweeping and peeling the lithium phosphate fine crystals attached to the inner wall of the reaction tank 1; Preferably, the bristles of the cleaning brush 32 are made of nylon material, and the length of the bristles is slightly longer than the gap between the tank walls. Through low-speed rotation of the rotating gear 33, the flexible bristles are used to sweep and peel the crystals. The vibration detachment mechanism 4 comprises two adjusting screws 41 screwed to the inner sides of the two sliding blocks 31, the top ends of the two adjusting screws 41 are both rotationally connected with a contact wheel 42, the inner side of the reciprocating frame 22 and located on the side opposite to the two sliding blocks 31 is provided with a spring 43, and the front side and the rear side of the inner wall of the reaction tank 1 are both fixedly provided with a vibration plate 44. Please refer to Figure 6 When the reciprocating belt 21 drives the reciprocating frame 22 to move to the right side, the contact wheel 42 contacts the vibration plate 44 and continuously moves to the right side, after the convex part of the contact wheel 42 contacts the vibration plate 44, the sliding block 31 slides backward in the inner side of the reciprocating frame 22 through the adjusting screw 41, so that the spring 43 is contracted, the sliding block 31 moves and drives the cleaning brush 32 to move backward, on the contrary, when the concave part of the contact wheel 42 contacts the vibration plate 44, the sliding block 31 drives the cleaning brush 32 to move forward through the expansion of the spring 43, through the forward and backward movement of the cleaning brush 32, the lithium phosphate fine crystals attached to the surface of the cleaning brush 32 are removed under the action of water flow; Preferably, by replacing the vibration plate 44 of different specifications and sizes, the vibration frequency and size of the cleaning brush 32 can be adjusted, when the contact wheel 42 is rotated downward by the adjusting screw 41, and the position of the contact wheel 42 is adjusted downward, when the reciprocating frame 22 moves to the right side, the contact wheel 42 does not contact the vibration plate 44; The surface of the vibration plate 44 is a concave-convex structure, when the contact wheel 42 contacts and walks along the vibration plate 44, the sliding block 31 can slide forward and backward in the inner side of the reciprocating frame 22 through the cooperation of the spring 43.

[0023] In this embodiment, when the reciprocating frame 22 is moved by the reciprocating belt 21, the cleaning brush 32 will rotate under the cooperation of the crystal tooth plate 34 and the rotating gear 33, thereby sweeping and peeling the lithium phosphate fine crystals adsorbed on the inner wall of the reaction tank 1. The reciprocating rotation of the cleaning brush 32 can efficiently peel these fine crystals, so that they re-enter the extraction system, thereby improving the overall recovery rate of lithium phosphate. For high-purity and high-value battery-grade lithium phosphate, the raw material loss can be significantly reduced, the production cost can be reduced, and the timely cleaning of the brush can avoid the long-term accumulation of crystals on the tank wall, reduce the interference of the reaction liquid uniformity, ensure the stability of the lithium phosphate crystallization process, and indirectly improve the purity and consistency of the final product. When the reciprocating frame 22 is moved to the right by the reciprocating belt 21 and continues to move to the right, the slider 31 drives the cleaning brush 32 to move forward and backward by the cooperation of the contact wheel 42 and the vibration plate 44, which can shake off the crystals attached to the surface in time, avoid the accumulation of lithium phosphate fine crystals on the brush, and has a self-cleaning function. The problem of the cleaning brush 32 being deteriorated due to oxidation and adsorption of impurities in the reaction system can be effectively avoided, the precision of the lithium phosphate product can be ensured, and the brush can always maintain a clean state to continuously and efficiently peel the crystals on the tank wall.

[0024] Second embodiment: Please refer to Figures 7 to 10 , the left side of the inner wall of the reaction tank 1 is provided with a monitoring mechanism 5, the monitoring mechanism 5 includes a rotating seat 51 fixed on the left side of the inner wall of the reaction tank 1, the inner side of the rotating seat 51 is rotatably connected with an industrial camera 52 through a rotating shaft, the industrial camera 52 is fixedly provided with an adjusting gear 53 through a rotating shaft, and the front side of the bottom of the reciprocating frame 22 is fixedly provided with a driving tooth plate 54. Please refer to Figure 7 and Figure 8 : when the reciprocating frame 22 drives the driving tooth plate 54 to move to the left, the driving tooth plate 54 contacts the adjusting gear 53 and continues to move to the left, the driving tooth plate 54 drives the adjusting gear 53 to rotate, the adjusting gear 53 drives the industrial camera 52 to rotate through the rotating shaft, thereby switching the industrial camera 52 to the working state, and the industrial camera 52 monitors the adsorption of lithium phosphate fine crystals on the tank wall and the working condition of the cleaning brush 32.

[0025] The left side of the inner wall of the reaction tank 1 is fixed with a detection mechanism 6, which includes a mounting plate 61 fixed to the left side of the inner wall of the reaction tank 1, two threaded guide rods 62 fixed to the right side of the mounting plate 61, a moving block 63 slidably connected to the surfaces of the two threaded guide rods 62, a follow-up frame 64 rotatably connected to the inner side of the moving block 63, a slot 65 opened in the inner side of the mounting plate 61, the rear side of the follow-up frame 64 located in the slot 65, a PH detector 66 arranged in the follow-up frame 64, and a trigger rod 67 threadedly connected to the inside of the reciprocating frame 22. Please combine Figure 9 and Figure 10 : By rotating the trigger rod 67, the working position of the left side of the trigger rod 67 is adjusted. When the reciprocating frame 22 continuously moves the trigger rod 67 to the left, the trigger rod 67 contacts the moving block 63 and pushes the moving block 63 to the left, causing the two reset springs 68 to contract. The left movement of the moving block 63 drives the left movement of the follow-up frame 64. Under the action of the slot 65, the follow-up frame 64 drives the PH detector 66 to rotate, so that the detection end of the PH detector 66 is inserted into the reaction liquid, and the PH concentration of the reaction liquid is detected. Further, when the reciprocating frame 22 moves the trigger rod 67 to the right, the expansion of the reset spring 68 causes the moving block 63 to slide to the right on the surface of the threaded guide rod 62. The movement of the moving block 63 drives the right movement of the follow-up frame 64. Under the action of the slot 65, the follow-up frame 64 drives the PH detector 66 to rotate clockwise, thereby resetting the position of the PH detector 66.

[0026] In this embodiment, when the reciprocating frame 22 continuously moves the drive tooth plate 54 to the left, the drive tooth plate 54 drives the adjustment gear 53 and the industrial camera 52 to rotate, thereby adjusting the industrial camera 52 to the working state. The industrial camera 52 can capture the crystal distribution of each area of the tank wall in real time, and then the movement speed of the reciprocating frame 22 or the vibration frequency of the cleaning brush 32 can be linked and controlled, thereby enhancing the stripping effect of the crystal. It can also monitor the abnormal state of the cleaning brush 32, so as to adjust or replace the cleaning brush 32 in time. When the reciprocating frame 22 continuously moves the trigger rod 67 to the left, the trigger rod 67 pushes the moving block 63 to the left. Under the cooperation of the follow-up frame 64 and the slot 65, the bottom end of the PH detector 66 is inserted into the reaction liquid, which can avoid the hysteresis of manual intermittent detection and ensure that the reaction system is always in the best PH range, providing a stable chemical environment for high-efficiency and high-purity lithium phosphate crystallization. At the same time, it can also avoid the problem of PH detector 66 always processing scale in the reaction liquid.

[0027] Third embodiment: Please refer to Figure 1 、 Figures 11 to 14 , the top of the reciprocating frame 22 is provided with a PH adjusting mechanism 7, the PH adjusting mechanism 7 comprises a solution tank 71 arranged on the top of the reciprocating frame 22, a pipe 72 is longitudinally rotatably connected in the reciprocating frame 22, a plurality of spray heads 73 are communicated on the surface of the pipe 72, two overturning gears 74 are fixedly arranged on the surface of the pipe 72, overturning tooth plates 75 are fixedly arranged on the front side and the rear side of the two mounting brackets 23, a water pump 76 is arranged on the front side of the top of the reciprocating frame 22, and the water pump 76 is communicated with the solution tank 71 and the pipe 72 through a hose; Please refer to Figure 11 and Figure 12 : start the water pump 76, the water pump 76 pumps the PH adjusting liquid in the solution tank 71 into the pipe 72, and then sprays the PH adjusting liquid into the reaction liquid through the spray head 73; Further, when the reciprocating frame 22 moves to the left side or the right side, the overturning gear 74 contacts the overturning tooth plate 75, and the overturning gear 74 drives the pipe 72 to rotate, so as to adjust the working angle of the spray head 73.

[0028] The inner wall of the reaction tank 1 is transversely rotatably connected with a mixing mechanism 8, the mixing mechanism 8 comprises a mixing shaft 81 transversely rotatably connected with the inner wall of the reaction tank 1, a plurality of mixing frames 82 are arranged on the surface of the mixing shaft 81, and a mixing motor 83 for driving the mixing shaft 81 to rotate is arranged on the right side of the reaction tank 1; Please refer to Figure 13 : start the mixing motor 83, the mixing motor 83 rotates to drive the mixing shaft 81 to rotate, the mixing shaft 81 rotates to drive the plurality of mixing frames 82 to rotate, and then the PH adjusting liquid and the reaction liquid are mixed.

[0029] Both ends of the mixing shaft 81 are fixedly provided with two arc-shaped plates 9 through bolts, a through groove is formed in the inner side of the arc-shaped plate 9, and a scraping plate 10 is fixedly arranged on the surface of the four arc-shaped plates 9. Two collecting grooves 11 are arranged on the bottom of the reaction tank 1, and a liquid discharge pipe 12 is communicated with the surface of the two collecting grooves 11; Please refer to Figure 14 : by loosening the bolts, the working position of the arc-shaped plate 9 can be adjusted, the contact distance between the scraping plate 10 and the groove wall is adjusted, the damage of the lithium phosphate fine crystal caused by excessive scraping force is avoided, and when the mixing shaft 81 rotates, the arc-shaped plate 9 and the scraping plate 10 are also rotated, so as to strip the crystal attached to the groove wall.

[0030] In this embodiment, the PH adjusting liquid is uniformly sprayed by the spray head 73 to avoid local pH sudden change, guarantee the best chemical environment for lithium phosphate crystallization or extraction, reduce impurity generation, the overturn gear 74 cooperates with the overturn tooth plate 75 to drive the pipeline 72 to rotate, the angle of the spray head 73 is adjusted, the working position of the arc-shaped plate 9 is adjusted by loosening the bolt, and then the contact distance between the scraping plate 10 and the groove wall is adjusted, so that the lithium phosphate fine crystal is not damaged due to excessive scraping force.

[0031] Fourth embodiment: Please refer to Figure 15 A process method for preparing lithium battery positive electrode material from lithium precipitation mother liquor, comprising the following steps: Step S1: uniformly mix the lithium precipitation mother liquor and concentrated sulfuric acid according to a proportion, control the PH to be neutral, remove the carbonate to obtain a decarbonized liquid; Step S2: preheat the obtained decarbonized liquid to a suitable temperature, then perform MVR evaporation and concentration to obtain a concentrated liquid; Step S3: centrifugal filtration is performed on the obtained concentrated liquid to obtain a sodium-potassium mixture and a concentrated filtrate; Step S4: the obtained concentrated filtrate is cooled to a suitable temperature to crystallize and precipitate, filtration is performed to obtain Na2SO4·H2O and a frozen filtrate, and then dehydration and drying are performed to obtain sodium sulfate; Step S5: the frozen filtrate is concentrated by an MVR evaporator, Li + to a suitable concentration to obtain a concentrated liquid; Step S6: prepare di(2-ethylhexyl) phosphate-sulfonated kerosene (volume ratio 1:3) as an extractant, add 5% tributyl phosphate as a co-extractant, extract the concentrated liquid according to a certain proportion, control the PH in a suitable range, perform three times of countercurrent washing to obtain an extracted liquid; Step S7: perform back extraction on the obtained extracted liquid and a phosphoric acid solution with a suitable concentration to obtain a LiH2PO4 solution, and adjust the PH to be alkaline to generate Li3PO4.

[0032] In this embodiment, impurities are efficiently removed through accurate decarburization, separation of sodium and potassium, and sodium sulfate, the product purity is guaranteed, and the battery-grade raw material requirement is met; MVR evaporation technology is used twice, energy consumption is greatly reduced, and production cost is saved; byproduct sodium sulfate is recovered, resource utilization rate and economy are improved; di(2-ethylhexyl) phosphate is used as an extractant in the extraction stage, tributyl phosphate is added as a co-extractant, three times of countercurrent washing is combined to strengthen selective separation of lithium, and the back extraction process is mild and efficient.

[0033] Please refer to Figures 1 to 14 The working principle of the equipment for preparing lithium battery positive electrode material from lithium precipitation mother liquor provided by the application is as follows: Step S1, start the drive motor 26, drive motor 26 rotates through two bevel gears 27 drive left drive wheel 24 rotation, left drive wheel 24 rotation in turn drive reciprocating belt 21 rotation, reciprocating belt 21 rotation drive reciprocating frame 22 moves, by controlling the direction of rotation of the drive motor 26, so that the reciprocating belt 21 drive reciprocating frame 22 to move left and right reciprocating; Step S2, start the water pump 76, water pump 76 will be the solution tank 71 in the PH adjusting liquid pumping to the pipeline 72, and then through the nozzle 73 will be PH adjusting liquid sprayed into the reaction liquid; When the reciprocating frame 22 moves to the left or right side, the turnover gear 74 is in contact with the turnover tooth plate 75, the turnover gear 74 will drive the pipeline 72 to rotate, so as to adjust the working angle of the nozzle 73; Start the mixing motor 83, the mixing motor 83 rotates to drive the mixing shaft 81 to rotate, the mixing shaft 81 rotates to drive the multiple mixing frames 82 to rotate, and the PH adjusting liquid and the reaction liquid are mixed; Step S3, by rotating the trigger rod 67, adjust the working position of the left side of the trigger rod 67, when the reciprocating frame 22 drives the trigger rod 67 to move continuously to the left, the trigger rod 67 is in contact with the moving block 63, the moving block 63 is pushed to the left, the two reset springs 68 are contracted, the moving block 63 moves to the left to drive the follower frame 64 to move to the left, under the action of the slot 65, the follower frame 64 drives the PH detector 66 to rotate, so that the detection end of the PH detector 66 is inserted into the reaction liquid, and then the PH concentration of the reaction liquid is detected; Step S4, when the reciprocating frame 22 drives the drive gear plate 54 to move to the left, the drive gear plate 54 is in contact with the adjusting gear 53, and continuously moves to the left, the drive gear plate 54 drives the adjusting gear 53 to rotate, the adjusting gear 53 rotates through the rotating shaft to drive the industrial camera 52 to rotate, so as to switch the industrial camera 52 to the working state, and the industrial camera 52 monitors the adsorption of lithium phosphate fine crystals on the groove wall; Step S5, when the reciprocating belt 21 drives the reciprocating frame 22 to move, the reciprocating frame 22 will drive the cleaning brush 32 and the rotating gear 33 to move at the same time, under the cooperation of the crystal removal gear plate 34 and the rotating gear 33, the cleaning brush 32 will rotate during the movement, and then the lithium phosphate fine crystals adsorbed on the inner wall of the reaction tank 1 are swept and peeled off; When the reciprocating belt 21 drives the reciprocating frame 22 to move to the right side, the contact wheel 42 contacts the convex part of the vibrating plate 44, and when the contact wheel 42 continuously moves to the right, the sliding block 31 slides backward in the inner side of the reciprocating frame 22 through the adjusting screw 41, so that the spring 43 is contracted, the sliding block 31 moves and drives the cleaning brush 32 to move backward, and vice versa, when the contact wheel 42 contacts the concave part of the vibrating plate 44, the sliding block 31 drives the cleaning brush 32 to move forward through the expansion of the spring 43, and through the forward and backward movement of the cleaning brush 32, the lithium phosphate fine crystals attached to the surface of the cleaning brush 32 are removed under the action of water flow.

[0034] The above description is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation, direct / indirect application in other related technical fields within the concept of the present application, and the contents of the present application specification and drawings are included in the patent protection scope of the present application.

Claims

1. An apparatus for preparing lithium battery cathode materials from lithium precipitation mother liquor, characterized in that, Includes a reaction tank, a moving mechanism, a crystal removal mechanism, and a vibration desorption mechanism; The moving mechanism includes a reciprocating belt and a reciprocating frame. The reciprocating frame is fixed to the surface of the reciprocating belt, and the reciprocating frame can be driven to reciprocate within the reaction tank by the rotation of the reciprocating belt. The crystal removal mechanism includes two sliders slidably connected to the inner side of the reciprocating frame. The inner sides of the two sliders are vertically rotatably connected to cleaning brushes. Rotating gears are fixed on the top surfaces of the two cleaning brushes. Crystal removal tooth plates are fixed on the front and rear sides of the inner wall of the reaction tank. The two crystal removal tooth plates mesh with the two rotating gears respectively. The vibration desorption mechanism includes adjusting screws threaded to the inner sides of two sliders. The top ends of the two adjusting screws are rotatably connected to contact wheels. Springs are provided on the inner side of the reciprocating frame and on the opposite side of the two sliders. Vibration plates are fixed on the front and rear sides of the inner wall of the reaction tank.

2. The apparatus for preparing lithium battery cathode materials from lithium-ion mother liquor according to claim 1, characterized in that, The surface of the vibrating plate has an uneven structure. When the contact wheel contacts the vibrating plate and moves, the slider can slide back and forth on the inner side of the reciprocating frame through the cooperation of the spring.

3. The apparatus for preparing lithium battery cathode materials from lithium-ion mother liquor according to claim 3, characterized in that, Mounting brackets are fixedly installed on both sides of the inner wall of the reaction tank. Drive wheels are rotatably connected to the inner sides of the two mounting brackets. The reciprocating belt is sleeved on the surface of the two drive wheels. Two guide seats are slidably connected to the bottom of the reciprocating frame. The two ends of the two guide seats are fixedly connected to the inner wall of the reaction tank. A drive motor is provided on the left side of the reaction tank. A bevel gear is fixedly installed at the output end of the drive motor and the front end of the left drive wheel. The two bevel gears mesh with each other.

4. The apparatus for preparing lithium battery cathode materials from lithium-ion mother liquor according to claim 1, characterized in that, A monitoring mechanism is fixedly installed on the left side of the inner wall of the reaction tank. The monitoring mechanism includes a rotating seat fixedly installed on the left side of the inner wall of the reaction tank. An industrial camera is rotatably connected to the inner side of the rotating seat via a rotating shaft. An adjusting gear is fixedly installed on the industrial camera via the rotating shaft. A drive gear plate is fixedly installed on the front side of the bottom of the reciprocating frame.

5. The apparatus for preparing lithium battery cathode materials from lithium-ion mother liquor according to claim 1, characterized in that, A detection mechanism is fixedly installed on the left side of the inner wall of the reaction tank. The detection mechanism includes a mounting plate fixedly installed on the left side of the inner wall of the reaction tank. Two threaded guide rods are fixedly installed on the right side of the mounting plate. A moving block is slidably connected to the surface of the two threaded guide rods. A follower frame is rotatably connected to the inner side of the moving block. A slot is opened on the inner side of the mounting plate. The rear side of the follower frame is located in the slot. A pH detector is installed inside the follower frame. A trigger rod is threadedly connected to the inside of the reciprocating frame. A reset spring is sleeved on the surface of each of the two threaded guide rods.

6. The apparatus for preparing lithium battery cathode materials from lithium-ion mother liquor according to claim 3, characterized in that, The top of the reciprocating frame is equipped with a pH adjustment mechanism, which includes a solution tank located on the top of the reciprocating frame. The reciprocating frame is longitudinally rotatably connected to a pipe, and the surface of the pipe is connected to multiple nozzles. Two flipping gears are fixed on the surface of the pipe. Flipping tooth plates are fixed on the front and rear sides of the two mounting brackets. A water pump is located on the front side of the top of the reciprocating frame, and the water pump is connected to the solution tank and the pipe through a hose.

7. The apparatus for preparing lithium battery cathode materials from lithium-ion mother liquor according to claim 1, characterized in that, The inner wall of the reaction tank is rotatably connected to a mixing mechanism. The mixing mechanism includes a mixing shaft rotatably connected to the inner wall of the reaction tank. Multiple mixing frames are provided on the surface of the mixing shaft. A mixing motor for driving the mixing shaft to rotate is provided on the right side of the reaction tank.

8. The apparatus for preparing lithium battery cathode materials from lithium-ion mother liquor according to claim 7, characterized in that, Two arc-shaped plates are fixed to both ends of the mixing shaft by bolts. A through groove is opened on the inner side of the arc-shaped plate. A scraping plate is fixed to the surface of each of the four arc-shaped plates. Two collection tanks are provided at the bottom of the reaction tank. A drain pipe is connected to the surface of each of the two collection tanks.

9. A process for preparing lithium battery cathode materials from lithium precipitation mother liquor, characterized in that, The process method includes the equipment and the following steps as described in any one of claims 1-8: Step S1: Mix lithium precipitation mother liquor and concentrated sulfuric acid in a uniform ratio, adjust the pH to neutral, and remove carbonate ions to obtain decarbonated liquor. Step S2: After preheating the obtained decarbonized liquid to a suitable temperature, perform MVR evaporation and concentration to obtain a concentrated liquid; Step S3: The obtained concentrate is centrifuged and filtered to obtain a sodium-potassium mixture and a concentrated filtrate; Step S4: Cool the obtained concentrated filtrate to a suitable temperature to crystallize and precipitate, filter to obtain Na2SO4·H2O and frozen filtrate, and then dehydrate and dry to obtain sodium sulfate; Step S5: Concentrate the frozen filtrate using an MVR evaporator to obtain Li + To obtain a concentrated solution at a suitable concentration; Step S6: Prepare di(2-ethylhexyl) phosphate-sulfonated kerosene (volume ratio 1:3) as the extractant, add 5% tributyl phosphate as a co-extractant, extract it with the concentrate in a certain ratio, adjust the pH to a suitable range, and perform three countercurrent washings to obtain the extract. Step S7: Back-extract the obtained extract with a phosphoric acid solution of suitable concentration to obtain a LiH2PO4 solution, and adjust the pH to alkaline to generate Li3PO4.

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