Process for the preparation of battery grade lithium carbonate from process waste liquor in combination with lithium mica leach liquor

Abstract

The application provides a device and method for preparing battery-grade lithium carbonate by mixing process waste liquid and lithium mica leaching liquid, relates to the technical field of lithium carbonate preparation, and comprises a heating reaction tank, a stirring mechanism, a driving mechanism and a quantitative feeding mechanism; the stirring mechanism is vertically arranged in the interior of the heating reaction tank and is used for mixing concentrated lithium liquid and soda, and comprises a rotating shaft; the driving mechanism comprises a rotating shaft, and the surfaces of the rotating shaft and the rotating shaft are fixedly provided with belt pulleys. Through the left and right movement of the reciprocating frame, the intermittent quantitative feeding of the boron adsorbent is realized, the waste of the boron adsorbent can be avoided, and the boron removal is not thorough due to the insufficient boron adsorbent. Meanwhile, through the rotation of the inclined blade paddle and the anchor paddle, the boron adsorbent and the concentrated lithium liquid can be synchronously mixed, the addition of the boron adsorbent can effectively reduce the inhibition of boric acid on the precipitation of lithium carbonate, the lithium recovery rate is significantly improved, the boron is prevented from being wrapped in the lithium carbonate crystal, the product can meet the demand of battery grade, and the product can meet the demand of battery grade.

Description

Technical Field

[0001] This invention relates to the field of lithium carbonate preparation, and more particularly to equipment and methods for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leachate. Background Technology

[0002] With the rapid development of the global new energy vehicle and energy storage industry, the demand for lithium resources has increased dramatically. Developing efficient and low-cost lithium extraction technology has become a research hotspot in the industry. As one of the important lithium resources, lepidolite has achieved industrial application of its sulfate roasting-water leaching process. However, the leachate often contains high concentrations of impurity ions in addition to lithium. It is necessary to go through multi-stage purification, concentration and lithium precipitation to obtain qualified battery-grade lithium carbonate. These processes generate some lithium-containing industrial waste liquid. Due to its complex composition and difficulty in treatment, its resource utilization value has not been fully explored.

[0003] In related technologies, when lepidolite raw materials contain boron, boric acid will be present in the leachate and concentrate. Boric acid reacts with carbonate ions to form stable complex ions, which in turn form soluble complexes with lithium. However, some existing battery-grade lithium carbonate preparation equipment is not conducive to effectively treating boric acid in the lepidolite leachate during operation. Boric acid severely inhibits the precipitation of lithium carbonate, resulting in abnormally low lithium recovery rates. Furthermore, even if precipitation occurs, boron may be trapped within the crystals, thus affecting the purity of lithium carbonate.

[0004] Therefore, it is necessary to provide equipment and methods for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leachate to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides an apparatus and method for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leachate, which solves the problem that some existing battery-grade lithium carbonate preparation equipment is not convenient for effectively treating boric acid in lepidolite leachate during operation.

[0006] To solve the above-mentioned technical problems, the equipment for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leaching solution provided by the present invention includes a heating reaction tank, a stirring mechanism, a driving mechanism, and a quantitative dispensing mechanism;

[0007] The stirring mechanism is vertically arranged inside the heating reaction tank and is used to mix concentrated lithium liquid and soda ash, including a rotating shaft;

[0008] The drive mechanism includes a rotating shaft, pulleys are fixedly mounted on the surfaces of the rotating shaft and the rotating shaft, belts are sleeved on the surfaces of the two pulleys, a rotating disk is fixedly mounted on the top of the rotating shaft, a drive wheel is threadedly connected to the rotating disk at a position away from the center, a reciprocating frame is provided on the surface of the drive wheel, and a connecting plate is fixedly mounted on the left side of the reciprocating frame.

[0009] The top of the heating reaction tank is fixedly equipped with an installation box. The quantitative dispensing mechanism includes two slide rails fixedly installed on the top of the inner wall of the installation box. A movable seat is slidably connected to one side of the two slide rails. The right side of the movable seat is fixedly connected to the left side of the connecting plate. A dispensing cup is fixedly installed on the inner side of the movable seat. A sealing cover is rotatably connected to the bottom of the dispensing cup. The bottom of the sealing cover is in contact with the top of the heating reaction tank.

[0010] Preferably, the rotating shaft is vertically rotatably connected to the inner side of the heating reaction tank and the mounting box. An inclined blade propeller and an anchor propeller are fixed on the surface of the rotating shaft and inside the heating reaction tank. A drive motor for driving the rotating shaft to rotate is provided on the top of the mounting box.

[0011] Preferably, the top of the heating reaction tank is provided with a feeding trough, which is at the same horizontal line as the feeding cup. When the feeding cup moves to the left and coincides with the position of the feeding trough, the sealing cover will rotate downwards due to gravity.

[0012] Preferably, a pre-wetting mechanism is fixedly provided on the left side of the inner wall of the mounting box. The pre-wetting mechanism includes a water cylinder fixedly provided on the left side of the inner wall of the mounting box. A sealing plug and a sliding rod are slidably connected to the inner side of the water cylinder. The left end of the sliding rod is fixedly connected to the right side of the sealing plug. A spring is sleeved on the surface of the sliding rod. A contact plate is fixedly provided on the right end of the sliding rod. A push plate is fixedly provided on the left side of the movable seat. A water outlet pipe is connected to the top of the water cylinder. A spray nozzle is connected to the bottom end of the water outlet pipe.

[0013] Preferably, a crushing and screening mechanism is fixedly provided at the top of the inner wall of the heating reaction tank. The crushing and screening mechanism includes a filter cover fixedly provided at the top of the inner wall of the heating reaction tank. A guide rod is horizontally fixedly provided on the inner wall of the filter cover. The inner side of the contact plate is slidably connected to the surface of the guide rod. A reset spring is sleeved on the circumferential side of the guide rod and located on the left side of the contact plate. A crushing frame is fixedly provided at the bottom of the contact plate.

[0014] Preferably, a liquid inlet mechanism is fixedly provided at the bottom of the heating reaction tank. The liquid inlet mechanism includes a mounting plate fixedly to the bottom of the heating reaction tank by bolts. A rotating shaft is rotatably connected to the mounting plate. A rotating frame is fixedly provided at the bottom end of the rotating shaft and inside the mounting plate. Multiple extrusion rollers are rotatably connected to the inner side of the rotating frame. A liquid inlet hose is provided inside the mounting plate. A liquid storage tank is provided at the bottom of the mounting plate. The two ends of the liquid inlet hose are respectively connected to the liquid storage tank and the heating reaction tank.

[0015] Preferably, a mounting bracket is fixedly provided on the right side of the top of the heating reaction tank, and an adjusting pipe is fixedly provided on the inner side of the mounting bracket. Multiple adjusting branch pipes are connected to the surface of the adjusting pipe, and the bottom ends of the multiple adjusting branch pipes penetrate through the top of the heating reaction tank and extend into the interior of the heating reaction tank.

[0016] Preferably, a support frame is fixed to the bottom of the heating reaction tank, a placement plate is fixed to the top of the support frame, the bottom of the liquid storage tank is located on the top of the placement plate, and a hopper is fixed to the left side of the top of the mounting box.

[0017] A method for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leachate includes the following steps:

[0018] Step S1: Mix the lithium mica leachate and the process filtrate in a certain proportion;

[0019] Step S2: Heat the mixture to 80-90℃ and add 1.4 times the theoretical amount of soda ash to remove calcium and magnesium;

[0020] Step S3: After the reaction has been going on for 1 hour, filter the mixture to obtain filter residue 1 and filtrate 1.

[0021] Step S4: Pass filtrate 1 into a chelating resin column at a certain rate to perform deep calcium removal and obtain purified lithium solution.

[0022] Step S5: Concentrate the purified lithium solution in a water bath at a certain temperature until a certain lithium concentration is reached to obtain concentrated lithium solution.

[0023] Step S6: Pass the concentrated lithium liquid into the heated reaction tank, and then add boron adsorbent and 1.2 times the theoretical amount of soda ash to the concentrated lithium liquid in sequence to precipitate lithium. After solid-liquid separation, obtain filtrate 2 and lithium carbonate.

[0024] Step S7: Wash, dry and pulverize the lithium carbonate obtained in step S6 with deionized water to obtain battery-grade lithium carbonate.

[0025] Step S8: Add H2SO4 to filtrate 2 from step S6 for decarbonization, then concentrate and filter to obtain sulfate and filtrate 3;

[0026] Step S9: Mix filtrate 3 with lepidolite leachate in a certain proportion and repeat the above operation to prepare battery-grade lithium carbonate.

[0027] Compared with related technologies, the equipment and method for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leachate provided by the present invention have the following beneficial effects:

[0028] When the moving seat moves the feeding cup to the left to the feeding trough position, the sealing cover rotates downwards due to gravity, causing the boron adsorbent inside the sealing cover to fall freely downwards into the concentrated lithium liquid. By moving the reciprocating frame left and right, the boron adsorbent is intermittently and quantitatively added, which can avoid excessive waste or insufficient boron removal caused by excessive boron adsorbent. At the same time, the rotation of the inclined blade and anchor blade can mix the boron adsorbent and concentrated lithium liquid simultaneously. The addition of boron adsorbent effectively reduces the inhibitory effect of boric acid on lithium carbonate precipitation, thereby significantly improving the lithium recovery rate and preventing boron from being trapped in lithium carbonate crystals, so that the product meets the requirements of battery grade.

[0029] By opening the installation box door and unscrewing the drive wheel, the drive wheel can be disengaged from the reciprocating frame. At this time, the rotating disc no longer drives the reciprocating frame, and the dispensing mechanism stops working. This allows for flexible handling of fluctuations in the boron content of the concentrated lithium liquid. When the boron content of the concentrated lithium liquid is extremely low, the dispensing of boron adsorbent can be paused to avoid ineffective cost consumption. When the boron content increases, dispensing can be resumed simply by resetting the drive wheel, without the need for complex modifications to the equipment. Attached Figure Description

[0030] 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.

[0031] Figure 1 The optimal structural schematic diagram provided for this invention;

[0032] Figure 2 This is a schematic diagram of the structure of the heating reaction tank provided by the present invention (cross-sectional view).

[0033] Figure 3 This is a schematic diagram of the stirring mechanism provided by the present invention;

[0034] Figure 4 A schematic diagram of the driving structure provided by the present invention;

[0035] Figure 5 A schematic diagram of the quantitative dispensing mechanism provided by the present invention;

[0036] Figure 6 A schematic diagram of the pre-wetting mechanism and the crushing and screening mechanism provided by the present invention;

[0037] Figure 7 for Figure 6 The diagram shows the state in which the movable seat moves the push plate to the left, squeezing the contact plate.

[0038] Figure 8 for Figure 6 The diagram shows a structural schematic of the cross-sectional view of the water cylinder.

[0039] Figure 9 This is a schematic diagram of the liquid inlet mechanism provided by the present invention;

[0040] Figure 10 for Figure 9 The diagram shows a structural schematic of the cross-sectional view of the mounting plate.

[0041] Figure 11 This is a schematic diagram of the method flow provided by the present invention.

[0042] Explanation of icon numbers:

[0043] 1. Heating reaction tank;

[0044] 2. Stirring mechanism; 21. Rotating shaft; 22. Inclined blade impeller; 23. Anchor blade impeller; 24. Drive motor;

[0045] 3. Drive mechanism; 31. Shaft; 32. Pulley; 33. Belt; 34. Rotary disc; 35. Drive wheel; 36. Reciprocating frame; 37. Connecting plate;

[0046] 4. Dispensing mechanism; 41. Slide rail; 42. Movable seat; 43. Dispensing cup; 44. Sealing cap;

[0047] 5. Installation box;

[0048] 6. Pre-wetting mechanism; 61. Water cylinder; 62. Sealing plug; 63. Slide rod; 64. Spring; 65. Contact plate; 66. Push plate; 67. Water outlet pipe; 68. Sprayer head;

[0049] 7. Crushing and screening mechanism; 71. Filter cover; 72. Guide rod; 73. Return spring; 74. Crushing frame;

[0050] 8. Liquid inlet mechanism; 81. Mounting plate; 82. Rotating frame; 83. Squeezing wheel; 84. Liquid inlet hose; 85. Liquid storage tank;

[0051] 9. Install bracket; 10. Adjusting pipe; 11. Adjusting branch pipe;

[0052] 12. Support frame; 13. Placement plate; 14. Hopper. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0054] This invention provides an apparatus and method for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leachate.

[0055] First embodiment:

[0056] Please see Figures 1 to 5 The equipment for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leaching solution includes a heating reaction tank 1, a stirring mechanism 2, a driving mechanism 3, and a quantitative dispensing mechanism 4.

[0057] The stirring mechanism 2 is vertically arranged inside the heating reaction tank 1 and is used to mix concentrated lithium liquid and soda ash, including a rotating shaft 21;

[0058] The rotating shaft 21 is vertically rotatably connected to the inner side of the heating reaction tank 1 and the mounting box 5. An inclined blade 22 and an anchor blade 23 are fixed on the surface of the rotating shaft 21 and inside the heating reaction tank 1. A drive motor 24 for driving the rotating shaft 21 to rotate is provided on the top of the mounting box 5.

[0059] Please combine Figure 3 Start the drive motor 24. The drive motor 24 rotates and drives the rotating shaft 21 to rotate. The rotating shaft 21 rotates and drives the inclined blade propeller 22 and the anchor propeller 23 to rotate, thereby mixing the concentrated lithium liquid and the materials.

[0060] The drive mechanism 3 includes a rotating shaft 31. Both the rotating shaft 31 and the rotating shaft 21 are fixedly provided with pulleys 32. The surfaces of the two pulleys 32 are fitted with belts 33. The top end of the rotating shaft 31 is fixedly provided with a rotating disk 34. The rotating disk 34 is threadedly connected to a drive wheel 35 at a position away from the center. The surface of the drive wheel 35 is provided with a reciprocating frame 36. The left side of the reciprocating frame 36 is fixedly provided with a connecting plate 37.

[0061] Please combine Figure 4 When the rotating shaft 21 rotates, it will drive the rotating shaft 31 to rotate simultaneously through the pulley 32 and the belt 33. The rotation of the rotating shaft 31 will then drive the rotating disk 34 and the drive wheel 35 to rotate. The rotation of the drive wheel 35 will drive the reciprocating frame 36 and the connecting plate 37 to move back and forth.

[0062] The top of the heating reaction tank 1 is fixedly provided with an installation box 5. The quantitative dispensing mechanism 4 includes two slide rails 41 fixedly provided on the top of the inner wall of the installation box 5. A movable seat 42 is slidably connected to one side of the two slide rails 41. The right side of the movable seat 42 is fixedly connected to the left side of the connecting plate 37. A dispensing cup 43 is fixedly provided on the inner side of the movable seat 42. A sealing cover 44 is rotatably connected to the bottom of the dispensing cup 43. The bottom of the sealing cover 44 is in contact with the top of the heating reaction tank 1.

[0063] Please combine Figure 5 When the connecting plate 37 moves to the left, it will simultaneously drive the moving seat 42 to move to the left. The moving seat 42 moves to the left, which in turn drives the feeding cup 43 and the sealing cover 44 to move to the left. When the sealing cover 44 is in the feeding trough position, the sealing cover 44 rotates downward under the influence of gravity, thereby causing the boron adsorbent inside the sealing cover 44 to fall freely downward and into the concentrated lithium liquid.

[0064] Furthermore, when the connecting plate 37 drives the movable seat 42 to move to the right, the movable seat 42 drives the dispensing cup 43 and the sealing cover 44 to move to the right. When the sealing cover 44 moves to the right and comes into contact with the inside of the heating reaction tank 1, it rotates clockwise, thereby resetting the sealing cover 44.

[0065] The top of the heating reaction tank 1 is provided with a feeding trough. The feeding trough and the feeding cup 43 are on the same horizontal line. When the feeding cup 43 moves to the left and coincides with the position of the feeding trough, the sealing cover 44 will rotate downward due to gravity.

[0066] Preferably, the inner side of the mounting box 5 is provided with a door, and the top of the door is provided with a handle. After opening the door with the handle, the drive wheel 35 is turned downwards to disengage the drive wheel 35 from the inner side of the reciprocating frame 36. Thus, when the rotating disk 34 rotates, the reciprocating frame 36 and the connecting plate 37 will not move in position.

[0067] Preferably, the right side of the feeding cup 43 is flat, and when the feeding cup 43 moves to the left, its flat top fits tightly against the discharge port of the hopper 14.

[0068] In this embodiment, when the moving seat 42 moves the feeding cup 43 to the left to the feeding trough position, the sealing cover 44 rotates downward under the influence of gravity, causing the boron adsorbent inside the sealing cover 44 to fall freely downward into the concentrated lithium liquid. By moving the reciprocating frame 36 left and right, the boron adsorbent is intermittently and quantitatively added, which can avoid excessive waste or insufficient boron removal caused by excessive boron adsorbent. At the same time, by rotating the inclined blade 22 and the anchor blade 23, the boron adsorbent and the concentrated lithium liquid can be mixed synchronously. By adding the boron adsorbent, the inhibitory effect of boric acid on lithium carbonate precipitation is effectively reduced, thereby significantly improving the lithium recovery rate and preventing boron from being wrapped in lithium carbonate crystals, so that the product meets the requirements of battery grade.

[0069] By opening the door of the installation box 5 and unscrewing the drive wheel 35, the drive wheel 35 can be disengaged from the reciprocating frame 36. At this time, the rotating disk 34 will no longer drive the reciprocating frame 36 to move, and the dispensing mechanism will stop working. This can flexibly cope with the fluctuation of boron content in the concentrated lithium liquid. When the boron content in the concentrated lithium liquid is extremely low, the dispensing of boron adsorbent can be suspended to avoid ineffective cost consumption. When the boron content increases, the dispensing can be resumed simply by resetting the drive wheel 35, without the need for complex modifications to the equipment.

[0070] Second embodiment:

[0071] Please see Figures 6 to 8 A pre-wetting mechanism 6 is fixedly installed on the left side of the inner wall of the mounting box 5. The pre-wetting mechanism 6 includes a water cylinder 61 fixedly installed on the left side of the inner wall of the mounting box 5. A sealing plug 62 and a sliding rod 63 are slidably connected to the inner side of the water cylinder 61. The left end of the sliding rod 63 is fixedly connected to the right side of the sealing plug 62. A spring 64 is sleeved on the surface of the sliding rod 63. A contact plate 65 is fixedly installed on the right end of the sliding rod 63. A push plate 66 is fixedly installed on the left side of the movable seat 42. A water outlet pipe 67 is connected to the top of the water cylinder 61. A nozzle 68 is connected to the bottom end of the water outlet pipe 67.

[0072] Please combine Figures 6 to 8 When the movable seat 42 moves to the left, it will simultaneously drive the push plate 66 to move to the left. When the push plate 66 moves to the left and contacts the contact plate 65, it will push the slide rod 63 to the left through the contact plate 65. The slide rod 63 moves to the left and drives the sealing plug 62 to move to the left, so that the water in the water cylinder 61 is sprayed out through the water outlet pipe 67 and the nozzle 68. The water sprayed out by the nozzle 68 will fall into the dispensing cup 43 to pre-wet the boron adsorbent.

[0073] Furthermore, when the movable seat 42 is reset to the right, under the action of the spring 64, the contact plate 65 drives the slide rod 63 and the sealing plug 62 to move to the right, thereby resetting the position of the sealing plug 62.

[0074] A crushing and screening mechanism 7 is fixedly provided on the top of the inner wall of the heating reaction tank 1. The crushing and screening mechanism 7 includes a filter cover 71 fixedly provided on the top of the inner wall of the heating reaction tank 1. A guide rod 72 is horizontally fixed on the inner wall of the filter cover 71. The inner side of the contact plate 65 is slidably connected to the surface of the guide rod 72. A return spring 73 is sleeved on the circumferential side of the guide rod 72 and located on the left side of the contact plate 65. A crushing frame 74 is fixedly provided at the bottom of the contact plate 65.

[0075] Please combine Figures 6 to 8 When the contact plate 65 moves to the left, it will simultaneously drive the bottom crushing frame 74 to move to the left, and at the same time cause the return spring 73 to contract. The crushing frame 74 moves to the left to crush the agglomerated boron adsorbent.

[0076] Furthermore, when the contact plate 65 resets to the right, the reset spring 73 expands, and the contact plate 65 moves to the right, causing the crushing frame 74 to move to the right, thereby resetting the crushing frame 74.

[0077] Preferably, the filter cover 71 is located at the bottom of the feeding trough, and the left side of the water cylinder 61 is connected to a water pumping pipe. Both the water pumping pipe and the water outlet pipe 67 are equipped with one-way valves.

[0078] In this embodiment, when the push plate 66 contacts the contact plate 65 and continues to move to the left, the contact plate 65 will push the slide rod 63 and the sealing plug 62 to the left, thereby spraying the water in the water cylinder 61 through the water outlet pipe 67 and the nozzle 68 to pre-wet the boron adsorbent. After pre-wetting, the surface of the adsorbent particles has been pre-coated with water molecules. When they enter the concentrated lithium liquid, they can be quickly and evenly dispersed into the entire liquid phase, avoiding clumping and floating phenomena.

[0079] When the contact plate 65 moves to the left, it will simultaneously drive the bottom crushing frame 74 to move to the left, and at the same time cause the return spring 73 to contract. The crushing frame 74 moves to the left to crush the agglomerated boron adsorbent. After being pre-wetted, the crushed fine adsorbent is dispersed into the concentrated lithium liquid more quickly under the action of stirring, avoiding local adsorbent accumulation.

[0080] Third embodiment:

[0081] Please see Figure 1 , Figure 9 and Figure 10 The bottom of the heating reaction tank 1 is fixedly provided with a liquid inlet mechanism 8. The liquid inlet mechanism 8 includes a mounting plate 81 fixed to the bottom of the heating reaction tank 1 by bolts. The rotating shaft 21 is rotatably connected to the mounting plate 81. The bottom end of the rotating shaft 21 and located inside the mounting plate 81 is fixedly provided with a rotating frame 82. Multiple extrusion rollers 83 are rotatably connected to the inner side of the rotating frame 82. A liquid inlet hose 84 is provided inside the mounting plate 81. A liquid storage tank 85 is provided at the bottom of the mounting plate 81. The two ends of the liquid inlet hose 84 are respectively connected to the liquid storage tank 85 and the heating reaction tank 1.

[0082] Please combine Figure 9 and Figure 10 When the rotating shaft 21 rotates, it will simultaneously drive the rotating frame 82 to rotate. The rotation of the rotating frame 82 will drive multiple extrusion rollers 83 to rotate. Through the rotation of the extrusion rollers 83, the liquid inlet hose 84 will be squeezed and released, creating a negative pressure inside the liquid inlet hose 84, thereby pumping the soda ash in the storage tank 85 into the heating reaction tank 1. When the rotating shaft 21 rotates faster, the amount pumped will also increase accordingly.

[0083] A mounting bracket 9 is fixedly provided on the right side of the top of the heating reaction tank 1. An adjusting pipe 10 is fixedly provided on the inner side of the mounting bracket 9. A plurality of adjusting branch pipes 11 are connected to the surface of the adjusting pipe 10. The bottom ends of the plurality of adjusting branch pipes 11 penetrate the top of the heating reaction tank 1 and extend into the interior of the heating reaction tank 1.

[0084] The bottom of the heating reaction tank 1 is fixedly provided with a support frame 12, the top of the support frame 12 is fixedly provided with a placement plate 13, the bottom of the liquid storage tank 85 is located on the top of the placement plate 13, and the left side of the top of the mounting box 5 is fixedly provided with a hopper 14.

[0085] Preferably, the bottom of the hopper 14 extends into the interior of the mounting box 5, and its outlet is perpendicular to the feeding cup 43. The material in the hopper 14 will fall freely into the feeding cup 43 due to gravity. The hopper 14 is used to hold boron adsorbent, the storage tank 85 is used to hold soda ash, and the regulating pipe 10 is used to transport pH adjuster.

[0086] In this embodiment, when the rotating shaft 21 rotates, it simultaneously drives the rotating frame 82 and multiple extrusion rollers 83 to rotate. Through the rotation of the extrusion rollers 83, the liquid inlet hose 84 is squeezed and released, creating a negative pressure inside the liquid inlet hose 84. This pumps the soda ash in the storage tank 85 into the heating reaction tank 1. The rotation speed of the rotating shaft 21 directly determines the squeezing frequency of the extrusion rollers 83 on the liquid inlet hose 84. In the early stage of the lithium precipitation reaction, soda ash needs to be added quickly to establish the reaction system. At this time, the stirring speed is high, the extrusion rollers 83 squeeze the hose at a high frequency, and the amount of soda ash pumped increases simultaneously. In the middle and later stages of the reaction, the addition rate needs to be slowed down to avoid local overabundance of carbonate ions. When the stirring speed is reduced, the amount of soda ash added decreases accordingly.

[0087] Fourth embodiment:

[0088] Please see Figure 11 A method for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leachate includes the following steps:

[0089] Step S1: Mix the lithium mica leachate and the process filtrate in a certain proportion;

[0090] Step S2: Heat the mixture to 80-90℃ and add 1.4 times the theoretical amount of soda ash to remove calcium and magnesium;

[0091] Step S3: After the reaction has been going on for 1 hour, filter the mixture to obtain filter residue 1 and filtrate 1.

[0092] Step S4: Pass filtrate 1 into a chelating resin column at a certain rate to perform deep calcium removal and obtain purified lithium solution.

[0093] Step S5: Concentrate the purified lithium solution in a water bath at a certain temperature until a certain lithium concentration is reached to obtain concentrated lithium solution.

[0094] Step S6: Pass the concentrated lithium liquid into the heated reaction tank 1, and then add boron adsorbent and 1.2 times the theoretical amount of soda ash to the concentrated lithium liquid in sequence to precipitate lithium. After solid-liquid separation, obtain filtrate 2 and lithium carbonate.

[0095] Step S7: Wash, dry and pulverize the lithium carbonate obtained in step S6 with deionized water to obtain battery-grade lithium carbonate.

[0096] Step S8: Add H2SO4 to filtrate 2 from step S6 for decarbonization, then concentrate and filter to obtain sulfate and filtrate 3;

[0097] Step S9: Mix filtrate 3 with lepidolite leachate in a certain proportion and repeat the above operation to prepare battery-grade lithium carbonate.

[0098] In this embodiment, the process waste liquid is returned to the process and mixed with the leachate, which reduces raw material consumption and wastewater discharge, while improving the overall lithium recovery rate. Secondly, a multi-stage deep impurity removal technology is adopted to ensure the high purity of the product. First, calcium and magnesium are initially removed by adding soda ash at high temperature, and then deep adsorption is carried out by using a chelating resin column, which can efficiently remove key impurity ions such as calcium and magnesium, laying a solid foundation for the subsequent preparation of battery-grade products. The use of boron adsorbent specifically solves the pain point of difficult removal of boron impurities in other methods. Furthermore, after the mother liquor after lithium precipitation is decarbonized and concentrated, not only are valuable sulfate by-products recovered, but the filtrate generated can also be returned to the system, minimizing waste generation and auxiliary material consumption.

[0099] Please refer to the reference again. Figures 1 to 11 The working principle of the equipment for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leachate provided by the present invention is as follows:

[0100] Step S1: Pump the concentrated lithium liquid into the heating reaction tank 1, turn on the stirring and heating system, raise the temperature of the liquid to 85-95℃, and then start the drive motor 24. The drive motor 24 rotates and drives the rotating shaft 21 to rotate. The rotating shaft 21 rotates and drives the inclined blade propeller 22 and the anchor propeller 23 to rotate.

[0101] When the rotating shaft 21 rotates, it will simultaneously drive the rotating shaft 31 to rotate via the pulley 32 and the belt 33. The rotation of the rotating shaft 31 will then drive the rotating disk 34 and the drive wheel 35 to rotate. The rotation of the drive wheel 35 will drive the reciprocating frame 36 and the connecting plate 37 to move back and forth.

[0102] In step S2, when the connecting plate 37 moves to the left, it will simultaneously drive the moving seat 42 to move to the left. The moving seat 42 moves to the left, which in turn drives the feeding cup 43 and the sealing cover 44 to move to the left. When the sealing cover 44 is in the feeding trough position, the sealing cover 44 rotates downward under the influence of gravity, causing the boron adsorbent inside the sealing cover 44 to fall freely downward and into the concentrated lithium liquid.

[0103] When the connecting plate 37 drives the moving seat 42 to move to the right, the moving seat 42 drives the feeding cup 43 and the sealing cover 44 to move to the right. When the sealing cover 44 moves to the right and comes into contact with the inside of the heating reaction tank 1, it rotates clockwise, thereby resetting the sealing cover 44. By moving the moving seat 42 back and forth, boron adsorbent is intermittently and quantitatively added to the heating reaction tank 1.

[0104] In step S3, when the movable seat 42 moves to the left, it will simultaneously drive the push plate 66 to move to the left. When the push plate 66 moves to the left and contacts the contact plate 65, it will push the slide rod 63 to the left through the contact plate 65. The slide rod 63 moves to the left and drives the sealing plug 62 to move to the left, so that the water in the water cylinder 61 is sprayed out through the water outlet pipe 67 and the nozzle 68. The water sprayed out by the nozzle 68 will fall into the dispensing cup 43 to pre-wet the boron adsorbent.

[0105] When the contact plate 65 moves to the left, it will simultaneously drive the bottom crushing frame 74 to move to the left, and at the same time cause the return spring 73 to contract. The crushing frame 74 moves to the left to crush the agglomerated boron adsorbent.

[0106] In step S4, after the boron adsorbent reaction is completed, the temperature of the liquid is raised to 90-95℃, and the drive motor 24 is started. The drive motor 24 drives the rotating shaft 21 to rotate. When the rotating shaft 21 rotates, it will simultaneously drive the rotating frame 82 to rotate. The rotating frame 82 drives multiple extrusion rollers 83 to rotate. Through the rotation of the extrusion rollers 83, the liquid inlet hose 84 is squeezed and released, so that a negative pressure is formed in the liquid inlet hose 84, thereby pumping the soda ash in the storage tank 85 into the heating reaction tank 1 to precipitate lithium in the concentrated lithium liquid. Lithium carbonate is obtained through solid-liquid separation.

[0107] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An apparatus for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leaching solution, characterized in that, It includes a heated reaction tank, a stirring mechanism, a driving mechanism, and a quantitative dispensing mechanism; The stirring mechanism is vertically arranged inside the heating reaction tank and is used to mix concentrated lithium liquid and soda ash, including a rotating shaft; The drive mechanism includes a rotating shaft, pulleys are fixedly mounted on the surfaces of the rotating shaft and the rotating shaft, belts are sleeved on the surfaces of the two pulleys, a rotating disk is fixedly mounted on the top of the rotating shaft, a drive wheel is threadedly connected to the rotating disk at a position away from the center, a reciprocating frame is provided on the surface of the drive wheel, and a connecting plate is fixedly mounted on the left side of the reciprocating frame. The top of the heating reaction tank is fixedly equipped with an installation box. The quantitative dispensing mechanism includes two slide rails fixedly installed on the top of the inner wall of the installation box. A movable seat is slidably connected to one side of the two slide rails. The right side of the movable seat is fixedly connected to the left side of the connecting plate. A dispensing cup is fixedly installed on the inner side of the movable seat. A sealing cover is rotatably connected to the bottom of the dispensing cup. The bottom of the sealing cover is in contact with the top of the heating reaction tank. A pre-wetting mechanism is fixedly installed on the left side of the inner wall of the installation box. The pre-wetting mechanism includes a water cylinder fixedly installed on the left side of the inner wall of the installation box. A sealing plug and a sliding rod are slidably connected to the inner side of the water cylinder. The left end of the sliding rod is fixedly connected to the right side of the sealing plug. A spring is sleeved on the surface of the sliding rod. A contact plate is fixedly installed on the right end of the sliding rod. A push plate is fixedly installed on the left side of the movable seat. A water outlet pipe is connected to the top of the water cylinder. A spray nozzle is connected to the bottom end of the water outlet pipe. A crushing and screening mechanism is fixedly installed at the top of the inner wall of the heating reaction tank. The crushing and screening mechanism includes a filter cover fixedly installed at the top of the inner wall of the heating reaction tank. A guide rod is horizontally fixedly installed on the inner wall of the filter cover. The inner side of the contact plate is slidably connected to the surface of the guide rod. A reset spring is sleeved on the circumferential side of the guide rod and on the left side of the contact plate. A crushing frame is fixedly installed at the bottom of the contact plate. When the movable seat moves to the left, it will simultaneously drive the push plate to move to the left. When the push plate moves to the left and contacts the contact plate, it will push the slide rod to the left through the contact plate. The top of the heating reaction tank is provided with a feeding trough, which is at the same horizontal line as the feeding cup. When the feeding cup moves to the left and coincides with the position of the feeding trough, the sealing cover will rotate downwards due to gravity.

2. The equipment for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leachate according to claim 1, characterized in that, The rotating shaft is vertically rotatably connected to the inner side of the heating reaction tank and the mounting box. An inclined blade and an anchor blade are fixed on the surface of the rotating shaft and inside the heating reaction tank. A drive motor for driving the rotating shaft to rotate is provided on the top of the mounting box.

3. The equipment for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leachate according to claim 1, characterized in that, The bottom of the heating reaction tank is fixedly equipped with a liquid inlet mechanism. The liquid inlet mechanism includes a mounting plate fixed to the bottom of the heating reaction tank by bolts. The rotating shaft is rotatably connected to the mounting plate. A rotating frame is fixedly installed at the bottom end of the rotating shaft and inside the mounting plate. Multiple extrusion rollers are rotatably connected to the inner side of the rotating frame. A liquid inlet hose is provided inside the mounting plate. A liquid storage tank is provided at the bottom of the mounting plate. The two ends of the liquid inlet hose are respectively connected to the liquid storage tank and the heating reaction tank.

4. The equipment for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leaching solution according to claim 1, characterized in that, A mounting bracket is fixedly installed on the right side of the top of the heating reaction tank. An adjusting pipe is fixedly installed on the inner side of the mounting bracket. Multiple adjusting branch pipes are connected to the surface of the adjusting pipe. The bottom ends of the multiple adjusting branch pipes penetrate the top of the heating reaction tank and extend into the interior of the heating reaction tank.

5. The equipment for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leaching solution according to claim 3, characterized in that, The bottom of the heating reaction tank is fixedly provided with a support frame, the top of the support frame is fixedly provided with a placement plate, the bottom of the liquid storage tank is located on the top of the placement plate, and a hopper is fixedly provided on the left side of the top of the mounting box.

6. A method for preparing battery-grade lithium carbonate by combining process waste liquid with lepidolite leachate, characterized in that, The method for preparing battery-grade lithium carbonate includes the apparatus and steps described in any one of claims 1-5 for preparing battery-grade lithium carbonate: Step S1: Mix the lithium mica leachate and the process filtrate in a certain proportion; Step S2: Heat the mixture to 80-90℃ and add 1.4 times the theoretical amount of soda ash to remove calcium and magnesium; Step S3: After the reaction has been going on for 1 hour, filter the mixture to obtain filter residue 1 and filtrate 1. Step S4: Pass filtrate 1 into a chelating resin column at a certain rate to perform deep calcium removal and obtain purified lithium solution. Step S5: Concentrate the purified lithium solution in a water bath at a certain temperature until a certain lithium concentration is reached to obtain concentrated lithium solution. Step S6: Pass the concentrated lithium liquid into the heated reaction tank, and then add boron adsorbent and 1.2 times the theoretical amount of soda ash to the concentrated lithium liquid in sequence to precipitate lithium. After solid-liquid separation, obtain filtrate 2 and lithium carbonate. Step S7: Wash, dry and pulverize the lithium carbonate obtained in step S6 with deionized water to obtain battery-grade lithium carbonate. Step S8: Add H2SO4 to filtrate 2 from step S6 for decarbonization, then concentrate and filter to obtain sulfate and filtrate 3; Step S9: Mix filtrate 3 with lepidolite leachate in a certain proportion and repeat the above operation to prepare battery-grade lithium carbonate.

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