Battery-grade lithium carbonate preparation equipment and process for preparing lithium carbonate and co-producing cryolite

Abstract

The invention provides battery-grade lithium carbonate preparation equipment and a process for preparing lithium carbonate and co-producing cryolite, and relates to the technical field of battery-grade lithium carbonate preparation, the battery-grade lithium carbonate preparation equipment comprises a base, a water bath tank, a treatment tank, a driven mechanism and a turnover mechanism; the water bath tank is mounted above the base, a heating seat is mounted on the outer wall of the water bath tank, a mounting frame is mounted at the top of the water bath tank, and an electric cylinder is mounted at the top of the mounting frame; the treatment tank is positioned inside the water bath tank. According to the scheme, when slurry at the bottom is turned over through the turnover mechanism, attached bubbles are stirred and polymerized to form larger bubbles, the larger bubbles float up to the liquid level more quickly to escape, then a turnover flow field can push the bubbles to rise quickly, the contact time of the bubbles and crystals is shortened, purity fluctuation caused by the bubbles is avoided, and the crystal quality is improved. And crystal mush deposited at the bottom can be directly turned upwards through the turnover mechanism and is fully mixed with an uncrystallized solution on the upper layer, so that the local concentration difference is broken, non-uniform crystal growth caused by deposition is avoided, and the quality of lithium carbonate crystallization can be further ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of battery-grade lithium carbonate preparation, in particular to a battery-grade lithium carbonate preparation device and a process for preparing lithium carbonate and by-product cryolite. BACKGROUND

[0002] At present, the treatment of lithium-containing electrolyte, a solid waste, is relatively simple in China. The electrolytic aluminum manufacturers return it after crushing to the aluminum electrolysis production, which not only leads to the accumulation of impurities in the electrolytic cell, reduces the current efficiency, increases the production cost, and makes the production stability poor and the electrolytic cell damage frequently, but also causes serious waste of lithium resources. With the rapid development of the new energy industry, the demand for lithium resources is increasing rapidly. Battery-grade lithium carbonate, as an important lithium product, has a strong market demand.

[0003] Battery-grade lithium carbonate is the core raw material for producing ternary lithium battery cathode materials. With the continuous development of lithium power batteries and energy storage batteries, and the increasing demand for clean and environmentally friendly and healthy performance in the downstream use process, the application range of lithium will be further expanded.

[0004] In the prior art, during the preparation of battery-grade lithium carbonate, the bottom of the treatment tank is designed in a circular arc, which is easy to form a stirring dead zone, and bubbles are easy to form at the bottom of the tank. Too many bubbles can cause crystal wrapping, which can affect the quality of the final product.

[0005] Therefore, it is necessary to provide a battery-grade lithium carbonate preparation device and a process for preparing lithium carbonate and by-product cryolite to solve the above technical problems. SUMMARY

[0006] The present application provides a battery-grade lithium carbonate preparation device and a process for preparing lithium carbonate and by-product cryolite, which solves the problem of easy bubble formation during the crystallization of battery-grade lithium carbonate in related technologies, which can affect the quality of the final product.

[0007] To solve the above technical problems, the battery-grade lithium carbonate preparation device provided by the present application comprises a base, a water bath tank, a treatment tank, a driven mechanism and a turnover mechanism.

[0008] The water bath tank is installed above the base, the water bath tank is provided with a heating seat on the outer wall, the water bath tank is provided with a mounting bracket on the top, and the mounting bracket is provided with an electric cylinder on the top.

[0009] The processing tank is located in the water bath tank, a first mounting cover is arranged on the top of the processing tank, a second mounting cover is arranged on the top of the first mounting cover, a motor is arranged on the top of the first mounting cover and in the second mounting cover, a stirring rod is connected to the key groove of the output shaft of the motor and located in the processing tank, a driven mechanism is located in the first mounting cover, the driven mechanism comprises a driven disc rotatably arranged on the axis of the first mounting cover, a positioning sleeve is fixedly arranged on the bottom of the driven disc and located in the processing tank, two limiting frames are arranged on the top of the driven disc, and a ratchet is rotatably connected to the limiting frame through a torsion spring, and a ratchet wheel is connected to the key groove of the outer wall of the stirring rod and located above the driven disc.

[0010] The overturning mechanism comprises a rotating ring fixedly arranged on the bottom of the stirring rod, two supports are fixedly arranged on the bottom of the processing tank, a trigger plate is rotatably arranged in each of the supports, a turning plate is fixedly arranged on the outer wall of the trigger plate, two convex plates are arranged on the bottom surface of the rotating ring through bolts, and a pipeline is arranged on the side wall of the processing tank.

[0011] Preferably, the second mounting cover is connected to the output shaft of the electric cylinder through bolts, and the stirring rod is rotatably connected to the axis of the first mounting cover through a bearing.

[0012] Preferably, the ratchet wheel is meshed with the two ratchets, the inner part of the rotating disc and the positioning sleeve is designed as hollow, and the stirring rod penetrates the axis of the rotating disc and the positioning sleeve without contacting the positioning sleeve and the rotating disc.

[0013] Preferably, the top end of each of the trigger plates contacts the lower surface of the rotating ring, and the supports, the trigger plates and the turning plates are mirror-distributed about the axis of the processing tank.

[0014] Preferably, the defoaming mechanism further comprises a defoaming disc.

[0015] The defoaming mechanism comprises a plurality of positioning frames fixedly arranged on the inner wall of the processing tank, a baffle is fixedly arranged on the outer wall of the positioning frame, a return spring is sleeved on the outer part of the positioning frame and located above the baffle, a defoaming disc is slidably connected above the positioning frame, two guide wheels are arranged on the top of the defoaming disc, and a plurality of arc protrusions are arranged on the bottom of the rotating disc.

[0016] Preferably, the plurality of arc protrusions are equidistantly and annularly distributed about the axis of the rotating disc, and the two guide wheels contact the arc protrusions.

[0017] Preferably, the axis of the defoaming disc is designed as hollow and does not contact the stirring rod, the plurality of positioning frames are equidistantly and annularly distributed about the axis of the defoaming disc, and the top end of the return spring contacts the bottom surface of the defoaming disc.

[0018] Preferably, a sealing plate is rotatably installed on the top of the water bath tank and on both sides of the mounting frame, a drain pipe is installed at the bottom of the water bath tank, and positioning blocks are fixedly arranged in a ring at equal intervals around the axis of the water bath tank at the bottom of the tank. A flip plate is rotatably connected inside the positioning block, and a movable plate is fixedly installed on the outer wall of the flip plate.

[0019] The process for preparing lithium carbonate and producing cryolite includes the following steps:

[0020] S1: The lithium-rich electrolyte is crushed by a jaw crusher, then ground by a planetary ball mill and sieved through a certain mesh. After sieving, it is placed in an oven and dried at a certain temperature for a period of time for later use.

[0021] S2: Weigh a certain amount of dried electrolyte, add deionized water to adjust the slurry concentration to 25%-40%, and add a certain mass fraction of sulfuric acid solution to adjust the pH to 1-2. Transfer the solution to a constant temperature water bath and react at a certain stirring speed and a specific temperature for a period of time.

[0022] S3: The slurry after the reaction is completed is sent for component testing. Based on the detected fluorine and aluminum content, aluminum sulfate is added to control the molar ratio of F / Al in the slurry. The water bath temperature is increased and the reaction continues for a period of time so that aluminum and fluoride ions in the solution undergo a displacement reaction, eventually forming an nNaF・AlF3 complex precipitate. Solid-liquid separation is performed to obtain filtrate A and filter residue A. Filter residue A is washed with deionized water according to a certain solid-liquid ratio three times, and then filtered and dried to obtain cryolite product. The washing liquid can be returned to step S2, the pulping process.

[0023] S4: Concentrate filtrate A and slowly add excess sodium carbonate saturated solution. Place it in a constant temperature water bath and react at a certain stirring speed and temperature for a period of time to carry out lithium precipitation reaction. After the reaction is completed, separate the solid and liquid to obtain filter residue B, which is mainly composed of crude lithium carbonate, and filtrate B, which is mainly composed of sodium sulfate. Filtrate B can be decarbonized and then freeze-crystallized to prepare sodium sulfate.

[0024] S5: Add filter residue B, whose main component is crude lithium carbonate, to deionized water to make slurry. Control the slurry concentration to 25%-40%. At room temperature, control the pressure of the diversion valve to 0.2-0.4MPa and introduce carbon dioxide gas to carbonize it. Stir at a certain speed and react for a period of time.

[0025] S6: Use ion exchange resin to deeply impurity the carbonized solution to remove calcium and magnesium ions, while controlling the flow rate to 16-20 L / h.

[0026] S7: Place the impurity-removed slurry in a constant temperature water bath and react it at a certain stirring speed and a specific temperature for a period of time to carry out decarbonization and crystallization. After solid-liquid separation and drying, battery-grade lithium carbonate is obtained. The stirring process in this step needs to be carried out in the processing tank. The constant temperature water bath requires the processing tank to be placed in the water bath tank. Users can control the temperature of the water bath tank through the heating base.

[0027] Compared with related technologies, the battery-grade lithium carbonate preparation equipment and the process for preparing lithium carbonate and producing cryolite provided by this invention have the following beneficial effects:

[0028] Carbon dioxide dissolved in the slurry tends to adhere to the bottom of the tank or the surface of the crystals. Simple stirring is not enough to completely remove it. When the bottom slurry is churned by the tumbling mechanism, the attached bubbles are stirred up, causing them to aggregate into larger bubbles and rise to the surface more quickly. Secondly, the churning flow field can push the bubbles to rise quickly, reducing the contact time between the bubbles and the crystals and avoiding purity fluctuations caused by bubbles. When the churning solution hits the liquid surface or the stirring rod, it can break the foam floating on the liquid surface, which can reduce the need for equipment modification and chemical reagent input.

[0029] Meanwhile, lithium carbonate crystals have a higher density than the solution, and they tend to deposit at the bottom of the tank during stirring, forming dead zones. The flipping mechanism can directly flip the crystal slurry deposited at the bottom upwards, fully mixing it with the uncrystallized solution above, breaking the local concentration difference, and avoiding uneven crystal growth caused by deposition, thus further ensuring the quality of lithium carbonate crystallization. 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 for Figure 1 The diagram shows a cross-sectional view of the water bath tank and the treatment tank.

[0033] Figure 3 for Figure 2 The diagram shows a cross-sectional view of the processing tank, the first mounting cover, and the second mounting cover.

[0034] Figure 4 for Figure 3 The diagram shown is a top-down view of the structure.

[0035] Figure 5This is a schematic diagram of the driven mechanism and defoaming mechanism shown in this invention;

[0036] Figure 6 for Figure 5 The diagram shown is a top-down view of the structure.

[0037] Figure 7 A detailed schematic diagram of the flipping mechanism provided by the present invention;

[0038] Figure 8 This is a detailed structural diagram of the bottom of the water bath tank provided by the present invention;

[0039] Figure 9 This is a schematic diagram of the process flow for preparing lithium carbonate and producing cryolite according to the present invention.

[0040] Explanation of icon numbers:

[0041] 1. Base, 2. Heating base, 3. Water bath tank, 4. Mounting bracket, 5. Electric cylinder, 6. Processing tank;

[0042] 7. Driven mechanism; 71. Driven disc; 72. Limiting bracket; 73. Racket; 74. Ratchet; 75. Positioning sleeve; 76. Turntable; 77. Arc protrusion.

[0043] 8. Defoaming mechanism; 81. Positioning frame; 82. Baffle; 83. Return spring; 84. Defoaming disc; 85. Guide wheel;

[0044] 9. Tilting mechanism; 91. Rotary ring; 92. Convex plate; 93. Bracket; 94. Trigger plate; 95. Flip plate;

[0045] 10. Pipe; 11. Sealing plate; 12. Drain pipe;

[0046] 13. Positioning block; 14. First mounting cover; 15. Second mounting cover;

[0047] 16. Motor, 17. Stirring rod, 18. Tilting plate, 19. Movable plate. Detailed Implementation

[0048] 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 them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] This invention provides battery-grade lithium carbonate preparation equipment and a process for preparing lithium carbonate and producing cryolite.

[0050] First embodiment:

[0051] Please see Figure 7 , Figures 1 to 3 Battery-grade lithium carbonate preparation equipment includes a base 1, a water bath tank 3, a processing tank 6, a driven mechanism 7, and a flipping mechanism 9;

[0052] The water bath tank 3 is installed above the base 1. A heating seat 2 is installed on the outer wall of the water bath tank 3. A mounting bracket 4 is installed on the top of the water bath tank 3. An electric cylinder 5 is installed on the top of the mounting bracket 4.

[0053] The processing tank 6 is located inside the water bath tank 3. A first mounting cover 14 is installed on the top of the processing tank 6. A second mounting cover 15 is installed on the top of the first mounting cover 14. A motor 16 is installed on the top of the first mounting cover 14 and inside the second mounting cover 15. A stirring rod 17 is connected to the keyway of the output shaft of the motor 16 inside the processing tank 6. The driven mechanism 7 is located inside the first mounting cover 14. The driven mechanism 7 includes a driven disk 71 rotatably mounted on the axis inside the first mounting cover 14. A positioning sleeve 75 is fixed at the bottom of the driven disk 71 and inside the processing tank 6. Two limiting frames 72 are installed on the top of the driven disk 71. Both limiting frames 72 are rotatably connected to ratchet teeth 73 through torsion springs. A ratchet wheel 74 is connected to the keyway of the outer wall of the stirring rod 17 above the driven disk 71.

[0054] The flipping mechanism 9 includes a rotating ring 91 fixed to the bottom of the stirring rod 17. Two supports 93 are fixed to the bottom of the processing tank 6. A trigger plate 94 is rotatably connected inside each of the two supports 93. A flip plate 95 is fixed to the outer wall of the trigger plate 94. Two protruding plates 92 are bolted to the bottom surface of the rotating ring 91. A pipe 10 is installed on the side wall of the processing tank 6.

[0055] The top of the second mounting cover 15 is bolted to the output shaft of the electric cylinder 5, and the top of the stirring rod 17 is rotatably connected to the axis of the first mounting cover 14 via a bearing.

[0056] The ratchet 74 is engaged with two ratchet teeth 73 on both sides. The turntable 76 and the positioning sleeve 75 are hollow inside. The stirring rod 17 passes through the axis of the turntable 76 and the positioning sleeve 75 and does not contact the positioning sleeve 75 or the turntable 76.

[0057] The top ends of the two trigger plates 94 are in contact with the lower surface of the rotating ring 91, and the bracket 93, trigger plates 94 and flip plate 95 are mirror-distributed about the axis of the processing tank 6.

[0058] Please see Figure 3 and Figure 4Users can inject the purified slurry into the processing tank 6 through the pipe 10, start the motor 16 to drive the stirring rod 17 to rotate clockwise, and continuously rotate and stir the purified slurry in the processing tank 6 through the stirring rod 17, which can decarbonize and crystallize, and obtain battery-grade lithium carbonate after solid-liquid separation and drying.

[0059] Please see Figure 3 and Figure 7 During the clockwise rotation of the stirring rod 17, the rotating ring 91 is driven to rotate synchronously. When the convex plate 92 at the bottom of the rotating ring 91 rotates to the top of the trigger plate 94, the convex plate 92 will resist and control the trigger plate 94 to flip from bottom to top. During the flipping process, the flip plate 95 is driven to flip upward synchronously. When the two flip plates 95 flip upward synchronously, the slurry at the bottom of the processing tank 6 can be turned upward and flow into the working range of the stirring rod 17.

[0060] This embodiment:

[0061] Carbon dioxide dissolved in the slurry tends to adhere to the bottom of the tank or the surface of the crystals. Simple stirring is not enough to completely remove it. When the bottom slurry is agitated by the tumbling mechanism 9, the attached bubbles are stirred up, causing them to aggregate into larger bubbles and rise to the surface of the liquid more quickly. Secondly, the tumbling flow field can push the bubbles to rise quickly, reducing the contact time between the bubbles and the crystals and avoiding purity fluctuations caused by bubbles. When the tumbling solution hits the liquid surface or the stirring rod 17, it can break the foam floating on the liquid surface, which can reduce the need for equipment modification and chemical reagent input.

[0062] Meanwhile, lithium carbonate crystals have a higher density than the solution, and are prone to depositing at the bottom of the tank during stirring, forming dead zones. The flipping mechanism 9 can directly flip the crystal slurry deposited at the bottom upwards, fully mixing it with the uncrystallized solution on the upper layer, breaking the local concentration difference, avoiding uneven crystal growth caused by deposition, and further ensuring the quality of lithium carbonate crystallization.

[0063] Second embodiment:

[0064] Please see Figure 3 , Figures 5 to 6 It also includes a defoaming mechanism 8;

[0065] The defoaming mechanism 8 includes multiple positioning frames 81 fixed to the inner wall of the treatment tank 6. A baffle 82 is fixed to the outer wall of the positioning frame 81. A return spring 83 is sleeved on the outside of the positioning frame 81 and above the baffle 82. A defoaming disc 84 is slidably connected above the multiple positioning frames 81. Two guide wheels 85 are installed on the top of the defoaming disc 84. Multiple arc protrusions 77 are provided at the bottom of the turntable 76.

[0066] Multiple arc-shaped protrusions 77 are equidistantly distributed in a ring around the axis of the turntable 76, and the two guide wheels 85 are in contact with the arc-shaped protrusions 77.

[0067] The defoaming disc 84 is hollow at its axis and does not contact the stirring rod 17. Multiple positioning frames 81 are equidistantly distributed in a ring around the axis of the defoaming disc 84. The top of the reset spring 83 is in contact with the bottom surface of the defoaming disc 84.

[0068] Please see Figure 5 In the first embodiment, the stirring rod 17 rotates clockwise, which drives the ratchet 74 to rotate clockwise. When the ratchet 74 rotates clockwise, it will avoid the ratchet 73. Therefore, in the first embodiment, when the stirring rod 17 stirs the slurry in the processing tank 6 clockwise, the driven mechanism 7 and the defoaming mechanism 8 will not work actively.

[0069] Please see Figure 5 and Figure 6 As the stirring enters the later crystallization stage, the user can control the stirring rod 17 to rotate counterclockwise according to the actual situation. The counterclockwise rotation can also control the stirring rod 17 to stir the slurry in the treatment tank 6. At the same time, when the ratchet 74 rotates counterclockwise, it can drive the ratchet 73 to drive the limit frame 72 to control the driven plate 71 to rotate. The driven plate 71 controls the positioning sleeve 75 to drive the turntable 76 to rotate.

[0070] During the rotation of the turntable 76, multiple arc-shaped protrusions 77 at the bottom can rotate. When each arc-shaped protrusion 77 rotates to the position of the guide wheel 85, it controls the guide wheel 85 to drive the defoaming disc 84 downward. When the defoaming disc 84 descends, it controls the return spring 83 to compress. As the arc-shaped protrusion 77 moves away from the guide wheel 85, the defoaming disc 84 automatically returns to its initial state. Thus, the turntable 76 can continuously rotate and control the defoaming disc 84 to move up and down repeatedly at the slurry surface position in the processing tank 6, thereby enabling mechanized treatment of bubble breaking on the liquid surface.

[0071] This embodiment:

[0072] During the reciprocating motion of the defoaming disc 84, it comes into direct contact with the foam on the liquid surface. Through mechanical compression and impact, it breaks larger bubbles into smaller bubbles. These smaller bubbles are easier to break, thus achieving the purpose of defoaming. The reciprocating motion of the defoaming disc 84 can more comprehensively cover the liquid surface and improve the defoaming efficiency. During the crystallization of lithium carbonate, carbon dioxide gas is continuously generated, causing continuous foam generation. The up-and-down movement of the defoaming disc 84 can continuously process the newly generated foam, keeping the foam on the liquid surface at a low level and providing a good environment for the crystallization process.

[0073] Secondly, excessive foam may overflow the tank, affecting the production environment and even causing production interruption. Defoaming plate 84 can effectively control the generation and accumulation of foam, reducing downtime and cleaning caused by foam problems, thereby improving the continuity and efficiency of production.

[0074] Third embodiment:

[0075] Please see Figure 1 , Figure 2 and Figure 8 A sealing plate 11 is rotatably installed on the top of the water bath tank 3 and on both sides of the mounting bracket 4. A discharge pipe 12 is installed at the bottom of the water bath tank 3. Positioning blocks 13 are fixedly arranged in a ring at equal intervals around the axis of the water bath tank 3 at the bottom of the water bath tank 3. A flip plate 18 is rotatably connected inside the positioning block 13. A movable plate 19 is fixedly installed on the outer wall of the flip plate 18.

[0076] Please see Figure 1 and Figure 2 During the water bath heating process, the user can control the electric cylinder 5 to drive the entire treatment tank 6 to move up and down in the water bath tank 3 along the vertical direction, thereby ensuring that the heat in the water bath tank 3 is fully in contact with the treatment tank 6 and ensuring a more constant temperature.

[0077] Please see Figure 2 and Figure 8 If the treatment tank 6 moves up and down inside the water bath tank 3, the bottom of the treatment tank 6 will be subjected to downward force to the top of the flip plate 18. The flip plate 18 controls the movable plate 19 to flip upward along the hinge position of the positioning block 13. By flipping upward synchronously by the four movable plates 19, the bottom medium of the water bath tank 3 can be turned upward and come into contact with the treatment tank 6.

[0078] This embodiment:

[0079] In traditional water bath heating, heat is mainly transferred through natural convection of hot water near the heating tube, which easily creates a low-temperature zone at the bottom of the tank. The tumbling design pushes the low-temperature medium at the bottom of the tank upwards, allowing it to mix thoroughly with the high-temperature medium above, thus avoiding local temperature fluctuations in the crystallization tank. If the treatment tank 6 experiences localized overheating due to the temperature difference in the water bath, the solution in that area may evaporate too quickly, resulting in excessively fine crystals or agglomeration. Conversely, if the area becomes too cold, the crystallization rate will slow down. The uniform temperature field provided by the tumbling design ensures that the solution temperature is consistent in all areas of the treatment tank 6, guaranteeing synchronized crystal growth rates and a more uniform particle size distribution.

[0080] The process for preparing lithium carbonate and producing cryolite includes the following steps:

[0081] S1: The lithium-rich electrolyte is crushed by a jaw crusher, then ground by a planetary ball mill and sieved through a certain mesh. After sieving, it is placed in an oven and dried at a certain temperature for a period of time for later use.

[0082] S2: Weigh a certain amount of dried electrolyte, add deionized water to adjust the slurry concentration to 25%-40%, and add a certain mass fraction of sulfuric acid solution to adjust the pH to 1-2. Transfer the solution to a constant temperature water bath and react at a certain stirring speed and a specific temperature for a period of time.

[0083] S3: The slurry after the reaction is completed is sent for component testing. Based on the detected fluorine and aluminum content, aluminum sulfate is added to control the molar ratio of F / Al in the slurry. The water bath temperature is increased and the reaction continues for a period of time so that aluminum and fluoride ions in the solution undergo a displacement reaction, eventually forming an nNaF・AlF3 complex precipitate. Solid-liquid separation is performed to obtain filtrate A and filter residue A. Filter residue A is washed with deionized water according to a certain solid-liquid ratio three times, and then filtered and dried to obtain cryolite product. The washing liquid can be returned to step S2, the pulping process.

[0084] S4: Concentrate filtrate A and slowly add excess sodium carbonate saturated solution. Place it in a constant temperature water bath and react at a certain stirring speed and temperature for a period of time to carry out lithium precipitation reaction. After the reaction is completed, separate the solid and liquid to obtain filter residue B, which is mainly composed of crude lithium carbonate, and filtrate B, which is mainly composed of sodium sulfate. Filtrate B can be decarbonized and then freeze-crystallized to prepare sodium sulfate.

[0085] S5: Add filter residue B, whose main component is crude lithium carbonate, to deionized water to make slurry. Control the slurry concentration to 25%-40%. At room temperature, control the pressure of the diversion valve to 0.2-0.4MPa and introduce carbon dioxide gas to carbonize it. Stir at a certain speed and react for a period of time.

[0086] S6: Use ion exchange resin to deeply impurity the carbonized solution to remove calcium and magnesium ions, while controlling the flow rate to 16-20 L / h.

[0087] S7: The slurry after impurity removal is placed in a constant temperature water bath and reacted at a certain stirring speed and temperature for a period of time to carry out decarbonization and crystallization. After solid-liquid separation and drying, battery-grade lithium carbonate is obtained. The stirring process in this step needs to be carried out in the processing tank 6. The constant temperature water bath needs to be carried out by placing the processing tank 6 in the water bath tank 3. The user can control the temperature of the water bath tank 3 through the heating seat 2.

[0088] This embodiment:

[0089] This approach aims to address the problems of resource waste, environmental pollution, and inability to meet market demand for battery-grade lithium carbonate and cryolite in existing lithium electrolyte processing methods, thereby achieving efficient and comprehensive utilization of fluorine and lithium resources and yielding significant economic, environmental, and social benefits.

[0090] Please refer to the reference again. Figures 1 to 9 The working principle of the battery-grade lithium carbonate preparation equipment and the process for preparing lithium carbonate and producing cryolite provided by this invention is as follows:

[0091] Step S1: The user flips open the sealing plate 11 to expose the pipe 10 outside the processing tank 6, and then injects the purified lithium carbonate slurry into the processing tank 6 through the pipe 10. After closing the sealing plate 11, the user submerges the processing tank 61 into the water bath tank 3 by controlling the electric cylinder 5. The heating seat 2 heats the water in the water bath tank 3 to keep the lithium carbonate slurry in the processing tank 6 at a constant temperature.

[0092] The start motor 16 drives the stirring rod 17 to rotate clockwise. The stirring rod 17 continuously rotates and stirs the impurity-removing slurry in the treatment tank 6, which can decarbonize and crystallize. After solid-liquid separation and drying, battery-grade lithium carbonate is obtained. During the clockwise rotation of the stirring rod 17, the rotating ring 91 is rotated synchronously. When the convex plate 92 at the bottom of the rotating ring 91 rotates to the top of the trigger plate 94, the convex plate 92 will resist and control the trigger plate 94 to flip from bottom to top. During the flipping process, the flip plate 95 is flipped upwards synchronously. When the two flip plates 95 flip upwards synchronously, the slurry at the bottom of the treatment tank 6 can be churned up and flow into the working range of the stirring rod 17, which can ensure that the lithium carbonate crystallization in the treatment tank 6 is more stable.

[0093] Step S2: Defoaming of the liquid surface inside treatment tank 6;

[0094] It is important to note that during the slurry injection process in the treatment tank 6, the liquid level of the lithium carbonate slurry must not exceed the defoaming plate 84, nor be lower than the defoaming plate 84. When the stirring enters the later crystallization stage, the user can control the stirring rod 17 to rotate counterclockwise according to the actual situation. The counterclockwise rotation can also control the stirring rod 17 to stir the slurry in the treatment tank 6. At the same time, when the ratchet 74 rotates counterclockwise, it can drive the ratchet 73 to drive the limit frame 72 to control the driven plate 71 to rotate. The driven plate 71 controls the positioning sleeve 75 to drive the turntable 76 to rotate.

[0095] During the rotation of the turntable 76, multiple arc-shaped protrusions 77 at the bottom can rotate. When each arc-shaped protrusion 77 rotates to the position of the guide wheel 85, it controls the guide wheel 85 to drive the defoaming disc 84 downward. When the defoaming disc 84 descends, it controls the return spring 83 to compress. As the arc-shaped protrusion 77 moves away from the guide wheel 85, the defoaming disc 84 automatically returns to its initial state. Thus, the turntable 76 can continuously rotate and control the defoaming disc 84 to move up and down repeatedly at the slurry surface position in the processing tank 6, thereby enabling mechanized treatment of bubble breaking on the liquid surface.

[0096] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. Battery-grade lithium carbonate preparation equipment, characterized in that, Includes a base, a water bath tank, a treatment tank, a driven mechanism, and a tilting mechanism; The water bath tank is installed above the base, a heating seat is installed on the outer wall of the water bath tank, a mounting bracket is installed on the top of the water bath tank, and an electric cylinder is installed on the top of the mounting bracket; The treatment tank is located inside the water bath tank. A first mounting cover is installed on the top of the treatment tank, and a second mounting cover is installed on top of the first mounting cover. A motor is installed on top of the first mounting cover and inside the second mounting cover. A stirring rod is connected to the keyway of the motor output shaft inside the treatment tank. The driven mechanism is located inside the first mounting cover. The driven mechanism includes a driven disc rotatably mounted on the axis inside the first mounting cover. A positioning sleeve is fixed at the bottom of the driven disc and inside the treatment tank. Two limit frames are installed on the top of the driven disc. Both limit frames are rotatably connected to ratchet teeth through torsion springs. A ratchet is connected to the keyway of the outer wall of the stirring rod above the driven disc. The flipping mechanism includes a rotating ring fixed to the bottom of the stirring rod. Two supports are fixed to the bottom of the processing tank. A trigger plate is rotatably connected inside each of the two supports. A flip plate is fixed to the outer wall of the trigger plate. Two protruding plates are bolted to the bottom surface of the rotating ring. Pipes are installed on the side wall of the processing tank.

2. The battery-grade lithium carbonate preparation equipment according to claim 1, characterized in that, The top of the second mounting cover is bolted to the output shaft of the electric cylinder, and the top of the stirring rod is rotatably connected to the axis of the first mounting cover via a bearing.

3. The battery-grade lithium carbonate preparation equipment according to claim 1, characterized in that, The ratchet is connected to the two ratchet teeth on both sides. The turntable and the positioning sleeve are hollow inside. The stirring rod passes through the axis of the turntable and the positioning sleeve and does not contact the positioning sleeve or the turntable.

4. The battery-grade lithium carbonate preparation equipment according to claim 1, characterized in that, The tops of the two trigger plates are in contact with the lower surface of the rotating ring, and the bracket, trigger plates and flaps are mirror-distributed about the axis of the processing tank.

5. The battery-grade lithium carbonate preparation equipment according to claim 1, characterized in that, It also includes a defoaming mechanism; The defoaming mechanism includes multiple positioning frames fixed to the inner wall of the treatment tank. A baffle is fixed to the outer wall of the positioning frame. A return spring is sleeved on the outside of the positioning frame and above the baffle. A defoaming disc is slidably connected above the multiple positioning frames. Two guide wheels are installed on the top of the defoaming disc. Multiple arc protrusions are provided on the bottom of the disc.

6. The battery-grade lithium carbonate preparation equipment according to claim 5, characterized in that, Multiple arc-shaped protrusions are equidistantly distributed in a ring around the center of the turntable, and the two guide wheels are in contact with the arc-shaped protrusions.

7. The battery-grade lithium carbonate preparation equipment according to claim 5, characterized in that, The defoaming disc has a hollow design at its axis and does not contact the stirring rod. Multiple positioning frames are equidistantly distributed in a ring around the axis of the defoaming disc. The top of the reset spring is in contact with the bottom surface of the defoaming disc.

8. The battery-grade lithium carbonate preparation equipment according to claim 1, characterized in that, A sealing plate is rotatably installed on the top of the water bath tank and on both sides of the mounting frame. A drain pipe is installed at the bottom of the water bath tank. Positioning blocks are fixedly arranged in a ring at equal intervals around the center of the water bath tank at the bottom of the tank. A flip plate is rotatably connected inside the positioning block. A movable plate is fixedly installed on the outer wall of the flip plate.

9. A process for preparing lithium carbonate and simultaneously producing cryolite, characterized in that, The process for preparing lithium carbonate and producing cryolite includes the battery-grade lithium carbonate preparation equipment as described in any one of claims 1-8, and includes the following steps: S1: The lithium-rich electrolyte is crushed by a jaw crusher, then ground by a planetary ball mill and sieved through a certain mesh. After sieving, it is placed in an oven and dried at a certain temperature for a period of time for later use. S2: Weigh a certain amount of dried electrolyte, add deionized water to adjust the slurry concentration to 25%-40%, and add a certain mass fraction of sulfuric acid solution to adjust the pH to 1-2. Transfer the solution to a constant temperature water bath and react at a certain stirring speed and a specific temperature for a period of time. S3: The slurry after the reaction is completed is sent for component testing. Based on the detected fluorine and aluminum content, aluminum sulfate is added to control the molar ratio of F / Al in the slurry. The water bath temperature is increased and the reaction continues for a period of time so that aluminum and fluoride ions in the solution undergo a displacement reaction, eventually forming an nNaF・AlF3 complex precipitate. Solid-liquid separation is performed to obtain filtrate A and filter residue A. Filter residue A is washed with deionized water according to a certain solid-liquid ratio three times, and then filtered and dried to obtain cryolite product. The washing liquid can be returned to step S2, the pulping process. S4: Concentrate filtrate A and slowly add excess sodium carbonate saturated solution. Place it in a constant temperature water bath and react at a certain stirring speed and temperature for a period of time to carry out lithium precipitation reaction. After the reaction is completed, separate the solid and liquid to obtain filter residue B, which is mainly composed of crude lithium carbonate, and filtrate B, which is mainly composed of sodium sulfate. Filtrate B can be decarbonized and then freeze-crystallized to prepare sodium sulfate. S5: Add filter residue B, whose main component is crude lithium carbonate, to deionized water to make slurry. Control the slurry concentration to 25%-40%. At room temperature, control the pressure of the diversion valve to 0.2-0.4MPa and introduce carbon dioxide gas to carbonize it. Stir at a certain speed and react for a period of time. S6: Use ion exchange resin to deeply impurity the carbonized solution to remove calcium and magnesium ions, while controlling the flow rate to 16-20 L / h. S7: Place the impurity-removed slurry in a constant temperature water bath and react it at a certain stirring speed and a specific temperature for a period of time to carry out decarbonization and crystallization. After solid-liquid separation and drying, battery-grade lithium carbonate is obtained. The stirring process in this step needs to be carried out in the processing tank. The constant temperature water bath requires the processing tank to be placed in the water bath tank. Users can control the temperature of the water bath tank through the heating base.

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