Equipment and process for preparing electrolyte raw material lithium fluoride from industrial-grade lithium carbonate

Abstract

The invention provides equipment and a process for preparing electrolyte raw material lithium fluoride from industrial-grade lithium carbonate, and relates to the technical field of electrolyte raw material preparation, the equipment comprises a jacketed reaction kettle, a sealing cover, a stirring mechanism and a dropwise adding mechanism; the stirring mechanism comprises a rotating shaft and a stirring paddle, the rotating shaft is vertically and rotatably connected to the inner side of the sealing cover, and the stirring paddle is fixedly arranged at the bottom of the rotating shaft; the dropwise adding mechanism comprises a key rod, a first eccentric wheel and a liquid outlet pipe, the key rod is horizontally arranged in the jacket reaction kettle, and the first eccentric wheel is connected with a key groove of the key rod. According to the scheme, the dropwise adding speed is in direct proportion to the stirring rotating speed through conical gear transmission, when stirring is faster, the dropwise adding speed of hydrofluoric acid can be synchronously increased, reaction lag caused by local excessive or too slow dropwise adding speed is avoided, full reaction of lithium and fluorine is guaranteed, explosive nucleation is avoided, the purity of a lithium fluoride product is effectively improved, and the service life of the lithium fluoride product is prolonged. And thus, the process performance of subsequent electrolyte preparation is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrolyte raw material preparation, and particularly to a device and process for preparing lithium fluoride from industrial-grade lithium carbonate. BACKGROUND

[0002] Lithium fluoride is an important inorganic compound of lithium, has unique physical and chemical properties, and is widely used in new energy, chemical industry, optics and other fields, especially in the field of electrolyte materials, is one of the key raw materials for high-performance lithium-based electrolyte.

[0003] In related technologies, lithium fluoride, as a key raw material for high-performance lithium battery electrolyte, can be prepared from industrial-grade lithium carbonate. However, the existing equipment is not convenient for controlling the amount of HF added when preparing lithium fluoride. If the addition speed of HF is too fast or the stirring is not sufficient, it will cause explosive nucleation, generating a large number of fine, colloidal LiF particles. This material is extremely difficult to filter, and the washing takes a very long time. After drying, the tap density is low, which will affect the process performance of subsequent electrolyte preparation and the electrochemical performance of the battery.

[0004] Therefore, it is necessary to provide a device and process for preparing lithium fluoride from industrial-grade lithium carbonate to solve the above technical problems. SUMMARY

[0005] The present application provides a device and process for preparing lithium fluoride from industrial-grade lithium carbonate, which solves the problem that the existing equipment is not convenient for controlling the amount of HF added when preparing lithium fluoride.

[0006] To solve the above technical problems, the device for preparing lithium fluoride from industrial-grade lithium carbonate provided by the present application comprises a jacketed reaction kettle, a sealing cover, a stirring mechanism and a dropping mechanism; The stirring mechanism comprises a rotating shaft and a stirring paddle, the rotating shaft is vertically connected to the inside of the sealing cover, and the stirring paddle is fixedly arranged at the bottom of the rotating shaft; The dropping mechanism comprises a key rod, a first eccentric wheel and a liquid outlet pipe, the key rod is horizontally arranged in the inside of the jacketed reaction kettle, the first eccentric wheel is connected with the key groove of the key rod, the top of the liquid outlet pipe is communicated with the sealing cover, a piston is slidably connected to the inner wall of the liquid outlet pipe, a reciprocating rod is fixedly arranged at the bottom end of the piston, an adjusting bracket is fixedly arranged at the bottom end of the reciprocating rod, a rotating wheel is arranged at the inside of the adjusting bracket, the bottom of the rotating wheel is matched with the top of the first eccentric wheel, a spring is arranged on the surface of the reciprocating rod, and a dropping tube is communicated with the liquid outlet pipe.

[0007] Preferably, the right end of the key rod and the surface of the rotating shaft are both fixedly provided with tapered teeth, the two tapered teeth are meshed with each other, the top of the sealing cover is communicated with a storage tank, and the top of the storage tank is provided with a protective cover.

[0008] Preferably, the surface of the rotating shaft is fixed with a plurality of stabilizing rods, the plurality of stabilizing rods are fixedly connected with the stirring paddle, and the top of the sealing cover is provided with a driving motor for driving the rotating shaft to rotate.

[0009] Preferably, the inner wall of the jacketed reaction kettle is fixed with a mounting seat, the top of the mounting seat is fixed with a driving mechanism, the driving mechanism comprises a mounting frame fixed to the top of the mounting seat, a guide rod is vertically and slidingly connected in the mounting frame, a driving frame is fixed to the top end of the guide rod, a second eccentric wheel is connected with the surface key groove of the key rod, the top of the driving frame is matched with the bottom of the second eccentric wheel, a tension spring is sleeved on the surface of the guide rod and in the mounting frame, a pressing block is fixed to the bottom of the tension spring, the top of the pressing block is fixedly connected with the bottom end of the guide rod, and the key rod is rotationally connected with the mounting frame.

[0010] Preferably, a wall scraping mechanism is slidingly connected in the mounting frame, the wall scraping mechanism comprises a sliding frame slidingly connected in the mounting frame, a rotating disc is rotationally connected in the sliding frame, a connecting plate is slidingly connected in the rotating disc, the inner side of the pressing block is slidingly connected with the inner side of the connecting plate, a connecting bracket is rotationally connected to the left side of the connecting plate, the inner side of the connecting bracket is slidingly connected with the mounting frame and the mounting seat, a scraper is fixed to the bottom of the connecting bracket, an adjusting screw is threadedly connected in the sliding frame, and the adjusting screw is rotationally connected with the jacketed reaction kettle.

[0011] Preferably, an exhaust mechanism is fixed to the right side of the top of the mounting seat, the exhaust mechanism comprises a mounting sleeve fixed to the right side of the top of the mounting seat, a filter plate is fixed to the inner wall of the mounting sleeve, a rotating shaft is rotationally connected to the inner side of the filter plate, an air suction fan is fixed to the bottom end of the rotating shaft, synchronous wheels are fixed to the surfaces of the rotating shaft and the rotating shaft, a synchronous belt is sleeved on the surfaces of the two synchronous wheels, and an exhaust pipe is communicated with the top of the mounting sleeve.

[0012] Preferably, the surface of the rotating shaft is provided with two connecting sleeves, the two connecting sleeves are fixedly connected by bolts, and connecting plates are fixed to the sides away from each other of the two connecting sleeves.

[0013] Preferably, a composite PH electrode is arranged in the mounting seat, a sound-light alarm is arranged on the top of the sealing cover, a feeding pipe is communicated with the surface of the jacketed reaction kettle, and a discharging pipe is communicated with the bottom of the jacketed reaction kettle.

[0014] A process for preparing industrial-grade lithium carbonate into lithium fluoride, which is an electrolyte raw material, comprises the following steps: Step S1, mixing industrial-grade lithium carbonate and water, then passing carbon dioxide to react for a certain time to obtain a lithium bicarbonate solution with a pH value of 8-14; Step S2, after the lithium bicarbonate solution is filtered at least twice, a filtrate is obtained, wherein the lithium carbonate that is not completely carbonated can be returned to step S1 again; Step S3, the filtrate is passed into a resin to remove impurities; Step S4, after the filtrate of step S3 is pyrolyzed at a certain temperature for a period of time, lithium carbonate and a pyrolysis liquid are obtained, and the pyrolysis liquid is returned to step S1; Step S5, the lithium carbonate is stirred and washed with water in a certain proportion to obtain high-purity lithium carbonate; Step S6, after the high-purity lithium carbonate is slurried with water in a certain proportion, the carbon dioxide is introduced into the environment at a certain temperature and pressure to react to obtain a refined lithium bicarbonate solution; Step S7, the refined lithium bicarbonate solution is introduced into a jacketed reactor, the refined lithium bicarbonate solution is continuously stirred, and hydrofluoric acid with a solute mass of 10% to 40% is added dropwise, to form a solid-liquid mixture after reaction at a certain temperature; Step S8, the solid-liquid mixture is filtered, the water is returned to step S1, and the filtrate is washed and vacuum dried to obtain battery-grade lithium fluoride.

[0015] Compared with the related art, the equipment and process for preparing electrolyte raw material lithium fluoride from industrial-grade lithium carbonate provided by the present application have the following beneficial effects: The piston is moved upward to push the hydrofluoric acid in the outlet pipe upward, at this time the height of the piston is higher than the height of the communication position of the dropping tube and the outlet pipe, so the dropping tube will not add hydrofluoric acid into the kettle, when the reciprocating rod drives the piston to move downward, at this time the height of the piston is lower than the height of the communication position of the dropping tube and the outlet pipe, so the dropping tube will add hydrofluoric acid into the kettle, by continuously moving the piston up and down, hydrofluoric acid is intermittently added into the kettle, the dropping speed is proportional to the stirring speed by the conical gear transmission, when the stirring is faster, the dropping speed of the hydrofluoric acid will also be accelerated synchronously, to avoid local excess or reaction lag caused by too fast dropping speed, to ensure sufficient reaction of lithium and fluorine, to avoid explosive nucleation, to effectively improve the purity of lithium fluoride product, and to improve the process performance of subsequent preparation of electrolyte. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings shown.

[0017] Figure 1 The best structural schematic diagram provided by the present application; Figure 2This is a schematic diagram of the cross-sectional view of the jacketed reactor provided by the present invention; Figure 3 This is a schematic diagram of the stirring mechanism provided by the present invention; Figure 4 This is a schematic diagram of the structure of the dripping mechanism provided by the present invention; Figure 5 for Figure 4 The diagram shows a cross-sectional view of the outlet pipe. Figure 6 for Figure 4 The enlarged structural diagram at point A is shown below; Figure 7 This is a schematic diagram of the drive mechanism and the wall scraping mechanism provided by the present invention; Figure 8 for Figure 7 The enlarged structural diagram at point B is shown below; Figure 9 This is a schematic diagram of the exhaust mechanism provided by the present invention; Figure 10 A structural schematic diagram of the sectional view of the mounting sleeve shown in Figure 9; Figure 11 A process flow diagram provided for this invention.

[0018] Explanation of icon numbers: 1. Jacketed reactor; 2. Sealing cover; 3. Stirring mechanism; 31. Rotating shaft; 32. Stirring paddle; 33. Stabilizing bar; 34. Drive motor; 4. Dropping mechanism; 41. Key rod; 42. First eccentric wheel; 43. Discharge pipe; 44. Piston; 45. Reciprocating rod; 46. Adjusting frame; 47. Rotating wheel; 48. Spring; 49. Dropper; 5. Conical teeth; 6. Storage tank; 7. Protective cover; 8. Mounting base; 9. Drive mechanism; 91. Mounting bracket; 92. Guide rod; 93. Drive frame; 94. Second eccentric wheel; 95. Tension spring; 96. Pressure block; 10. Scraping mechanism; 101. Sliding frame; 102. Rotary disc; 103. Connecting plate; 104. Connecting bracket; 105. Scraper; 106. Adjusting screw; 11. Exhaust mechanism; 111. Mounting sleeve; 112. Filter plate; 113. Shaft; 114. Exhaust fan; 115. Synchronous pulley; 116. Synchronous belt; 117. Exhaust pipe; 12. Connecting sleeve; 13. Connecting plate; 14. Defoaming bracket; 15. Composite pH electrode; 16. Audible and visual alarm; 17. Discharge pipe. Detailed Implementation

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0020] The application provides a device and a process for preparing lithium fluoride, an electrolyte raw material, from industrial-grade lithium carbonate.

[0021] First embodiment: Please refer to Figures 1 to 6 A device for preparing lithium fluoride, an electrolyte raw material, from industrial-grade lithium carbonate, comprising a jacketed reaction kettle 1, a sealing cover 2, a stirring mechanism 3 and a dropping mechanism 4. Preferably, the jacketed reaction kettle 1 is connected with a constant-temperature circulating oil bath, and the temperature of the reaction liquid is accurately controlled in a set range through a PID temperature controller. The stirring mechanism 3 comprises a rotating shaft 31 and a stirring paddle 32, the rotating shaft 31 is vertically rotatably connected to the inner side of the sealing cover 2, and the stirring paddle 32 is fixedly arranged at the bottom of the rotating shaft 31. A plurality of stabilizing rods 33 are fixedly arranged on the surface of the rotating shaft 31, the stabilizing rods 33 are fixedly connected with the stirring paddle 32, and the top of the sealing cover 2 is provided with a driving motor 34 for driving the rotating shaft 31 to rotate. Please refer to Figure 3 : Start the driving motor 34, and the driving motor 34 rotates to drive the rotating shaft 31 to rotate, and the rotating shaft 31 rotates to drive the stabilizing rods 33 and the stirring paddle 32 to rotate, so as to stir and mix the reaction liquid. The dropping mechanism 4 comprises a key rod 41, a first eccentric wheel 42 and a liquid outlet pipe 43, the key rod 41 is horizontally arranged in the jacketed reaction kettle 1, the first eccentric wheel 42 is connected with the key groove of the key rod 41, the top of the liquid outlet pipe 43 is communicated with the sealing cover 2, a piston 44 is slidably connected with the inner wall of the liquid outlet pipe 43, a reciprocating rod 45 is fixedly arranged at the bottom end of the piston 44, an adjusting frame 46 is fixedly arranged at the bottom end of the reciprocating rod 45, a rotating wheel 47 is arranged on the inner side of the adjusting frame 46, the bottom of the rotating wheel 47 is in abutment with the top of the first eccentric wheel 42, a spring 48 is sleeved on the surface of the reciprocating rod 45, and a dropping tube 49 is communicated with the liquid outlet pipe 43. The right end of the key rod 41 and the surface of the rotating shaft 31 are both fixedly provided with a conical tooth 5, the two conical teeth 5 are in meshing engagement, the top of the sealing cover 2 is communicated with a storage tank 6, and the top of the storage tank 6 is provided with a protective cover 7. Please refer to Figures 4 to 6When the rotating shaft 31 rotates, the two conical gears 5 drive the key bar 41 to rotate, the key bar 41 rotates and drives the first eccentric wheel 42 to rotate, and the first eccentric wheel 42 rotates to drive the reciprocating rod 45 to move up and down under the action of the adjusting frame 46 and the rotating wheel 47. When the reciprocating rod 45 moves upwards, it drives the piston 44 to move upwards, thereby pushing the hydrofluoric acid in the liquid outlet pipe 43 upwards. At this time, the height of the piston 44 is higher than the height of the communication position of the dropper 49 and the liquid outlet pipe 43, so the dropper 49 will not drop hydrofluoric acid into the kettle. When the reciprocating rod 45 drives the piston 44 to move downwards, the height of the piston 44 is lower than the height of the communication position of the dropper 49 and the liquid outlet pipe 43, so the dropper 49 will drop hydrofluoric acid into the kettle. Through the continuous up-and-down movement of the reciprocating rod 45, the hydrofluoric acid is intermittently added into the kettle. Further, when the rotating speed of the rotating shaft 31 and the stirring paddle 32 increases, the rotating speed of the key bar 41 driving the first eccentric wheel 42 will also increase, and the dropping speed of the hydrofluoric acid will also increase. The dropping speed is proportional to the rotating speed of the stirring paddle 32, thereby avoiding the problem that the dropping speed of the hydrofluoric acid is too fast and the stirring is insufficient. Preferably, the inner side of the adjusting frame 46 is provided with an adjusting groove, the rotating wheel 47 is fixedly connected with the adjusting frame 46 through a bolt, the rotating wheel 47 is rotatably connected with the bolt, the top and bottom of the spring 48 are fixedly connected with the liquid outlet pipe 43 and the adjusting frame 46 respectively, and the storage tank 6 is in communication with the liquid outlet pipe 43. Preferably, by adjusting the installation position of the bolt and the adjusting frame 46, the working height of the rotating wheel 47 can be adjusted, and the liquid outlet pipe 43 can be communicated with two droppers 49, thereby adding hydrofluoric acid into the kettle at two different positions.

[0022] In this embodiment, the hydrofluoric acid in the liquid outlet pipe 43 is pushed upwards by the upward movement of the piston 44. At this time, the height of the piston 44 is higher than the height of the communication position of the dropper 49 and the liquid outlet pipe 43, so the dropper 49 will not drop hydrofluoric acid into the kettle. When the reciprocating rod 45 drives the piston 44 to move downwards, the height of the piston 44 is lower than the height of the communication position of the dropper 49 and the liquid outlet pipe 43, so the dropper 49 will drop hydrofluoric acid into the kettle. Through the continuous up-and-down movement of the piston 44, the hydrofluoric acid is intermittently added into the kettle. The dropping speed is proportional to the stirring speed by the transmission of the conical gear 5. When the stirring is faster, the dropping speed of the hydrofluoric acid will also increase synchronously, thereby avoiding the problem that the dropping speed is too fast or the reaction is lagging due to the slow dropping speed, ensuring the sufficient reaction of lithium and fluorine, avoiding the explosive nucleation, effectively improving the purity of the lithium fluoride product, and further improving the process performance of the subsequent preparation of the electrolyte.

[0023] Second embodiment Please refer to Figure 7 and Figure 8The inner wall of the jacketed reaction kettle 1 is fixedly provided with a mounting seat 8, the top of the mounting seat 8 is fixedly provided with a driving mechanism 9, the driving mechanism 9 comprises a mounting frame 91 fixedly arranged at the top of the mounting seat 8, a guide rod 92 is vertically and slidingly connected in the mounting frame 91, the top end of the guide rod 92 is fixedly provided with a driving frame 93, the surface key groove of the key rod 41 is connected with a second eccentric wheel 94, the top of the driving frame 93 is matched with the bottom of the second eccentric wheel 94, the surface of the guide rod 92 and located in the inside of the mounting frame 91 is sleeved with a tension spring 95, the bottom of the tension spring 95 is fixedly provided with a pressing block 96, the top of the pressing block 96 is fixedly connected with the bottom end of the guide rod 92, and the key rod 41 is rotationally connected with the mounting frame 91; Please combine Figure 7 and Figure 8 : when the key rod 41 rotates, the second eccentric wheel 94 is also rotated, and the rotation of the second eccentric wheel 94 drives the guide rod 92 to drive the pressing block 96 to move up and down through the driving frame 93; The inside of the mounting frame 91 is slidingly connected with a wall scraping mechanism 10, the wall scraping mechanism 10 comprises a sliding frame 101 slidingly connected in the inside of the mounting frame 91, a rotating disc 102 is rotationally connected in the inside of the sliding frame 101, a connecting plate 103 is slidingly connected in the inside of the rotating disc 102, the inner side of the pressing block 96 is slidingly connected with the inner side of the connecting plate 103, a connecting support 104 is rotationally connected to the left side of the connecting plate 103, the inner side of the connecting support 104 is slidingly connected with the mounting frame 91 and the mounting seat 8, a scraper 105 is fixedly arranged at the bottom of the connecting support 104, an adjusting screw 106 is threadedly connected in the inside of the sliding frame 101, and the adjusting screw 106 is rotationally connected with the jacketed reaction kettle 1; Please combine Figure 7 and Figure 8 : when the pressing block 96 moves downward, the right side of the connecting plate 103 is pressed downward, the rotating disc 102 rotates clockwise, the left side of the connecting plate 103 is raised upward, and the scraper 105 is driven by the connecting support 104 to move upward, when the pressing block 96 moves upward under the action of the tension spring 95, the pressing block 96 drives the connecting plate 103 to reset upward, under the action of gravity, the connecting support 104 and the scraper 105 move downward in the resetting process of the connecting plate 103, and the scraper 105 moves upward and downward through the continuous rotation of the second eccentric wheel 94, so that the lithium fluoride crystals attached to the kettle wall are scraped off, and they are prevented from growing and blocking, thereby affecting heat transfer and product purity; Further, the rotating adjusting screw 106 drives the sliding frame 101 to move rightward, the sliding frame 101 drives the rotating disc 102 to move rightward, so as to change the point position of the rotation of the connecting plate 103, and then the height of the left side of the connecting plate 103 can be adjusted.

[0024] In this embodiment, the wall scraping mechanism 10 relies on the rotating power of the key lever 41, moves the guide rod 92 and the pressing block 96 up and down through the second eccentric wheel 94, and then converts it into the reciprocating lifting movement of the scraper 105 through the connecting plate 103 and the connecting bracket 104, which can scrape off the lithium fluoride crystals attached to the inner wall of the jacketed reactor 1 in real time. Since lithium fluoride is prone to precipitate and adhere to the wall during the reaction due to local temperature fluctuations and high concentration, long-term accumulation will form large crystalline bodies, which not only wrap unreacted impurities, leading to a decrease in the purity of the final product, but also affect the uniformity of the crystals, which does not meet the requirements of battery-grade lithium fluoride. The continuous scraping of the scraper 105 can strip and disperse the attached crystals into the reaction solution in time, ensuring uniform product particles and controllable impurity content.

[0025] Third embodiment: Please refer to Figure 2 、 Figure 3 、 Figure 9 and Figure 10 , the right side of the top of the mounting seat 8 is fixedly provided with an exhaust mechanism 11, the exhaust mechanism 11 includes a mounting sleeve 111 fixedly provided on the right side of the top of the mounting seat 8, the inner wall of the mounting sleeve 111 is fixedly provided with a filter plate 112, the inner side of the filter plate 112 is rotatably connected with a rotating shaft 113, the bottom end of the rotating shaft 113 is fixedly provided with an exhaust fan 114, the surfaces of the rotating shaft 31 and the rotating shaft 113 are both fixedly provided with synchronous wheels 115, the surfaces of the two synchronous wheels 115 are sleeved with a synchronous belt 116, and the top of the mounting sleeve 111 is communicated with an exhaust pipe 117. Please refer to Figure 9 and Figure 10 : when the rotating shaft 31 rotates, it will simultaneously drive the rotating shaft 113 to rotate through the synchronous wheels 115 and the synchronous belt 116, and the rotating shaft 113 will in turn drive the exhaust fan 114 to rotate, and the exhaust fan 114 will rotate to exhaust the gas in the reactor through the exhaust pipe 117. Preferably, the exhaust pipe 117 is connected with a condenser made of PTFE material, which condenses the volatilized material, and the outlet of the condenser is connected with a tail gas absorption bottle containing sodium hydroxide solution, which is used to neutralize the possible escape of trace HF acid gas to ensure that the exhaust gas meets the emission standard. The surface of the rotating shaft 31 is provided with two connecting sleeves 12, the two connecting sleeves 12 are fixedly connected by bolts, and the sides away from each other of the two connecting sleeves 12 are both fixedly provided with a connecting plate 13, and the surfaces of the two connecting plates 13 are both fixedly provided with a defoaming bracket 14. When the rotating shaft 31 rotates, it will simultaneously drive the two connecting sleeves 12 to rotate, and the two connecting plates 13 will in turn drive the defoaming bracket 14 to rotate, and through the rotation of the defoaming bracket 14, the foam on the liquid surface will be eliminated.

[0026] The inside of the mounting seat 8 is provided with a composite PH electrode 15, the top of the sealing cover 2 is provided with an audible and light alarm 16, the surface of the jacketed reaction kettle 1 is communicated with a feeding pipe, and the bottom of the jacketed reaction kettle 1 is communicated with a discharging pipe 17; Preferably, the composite PH electrode 15 is used for monitoring the PH value of the reaction liquid in real time, a PH meter signal is connected to a PH controller, when the PH approaches the end point, an audible and light alarm is sent through the audible and light alarm 16 to prompt the operator, and when the PH reaches the preset end point value, the PH controller sends a signal to directly cut off the power supply of the driving motor 34, after the driving motor 34 is powered off, the stirring and dropping are synchronously stopped, and the addition of HF can be avoided.

[0027] In the embodiment, the exhaust mechanism 11 is driven to rotate by the driving force of the rotating shaft 31, the synchronous wheel 115 and the synchronous belt 116 are used to drive the air suction fan 114 to rotate, the generated gas and the volatilized gas of hydrofluoric acid in the kettle can be sucked out in real time, compared with passive exhaust, active air suction can avoid the local pressure fluctuation caused by the accumulation of gas in the kettle, prevent the reaction stability from being affected due to the pressure imbalance, and reduce the corrosion of the equipment caused by the residual hydrofluoric acid vapor in the kettle.

[0028] Fourth embodiment: Please refer to Figure 11 A process for preparing lithium fluoride as an electrolyte raw material from industrial-grade lithium carbonate, comprising the following steps: Step S1, mixing industrial-grade lithium carbonate and water, then passing carbon dioxide to react for a certain time to obtain a lithium bicarbonate solution with a PH value of 8-14; Preferably, the ratio of industrial-grade lithium carbonate to water is 1:8-1:20, the temperature is 20-40 DEG C, the carbon dioxide is passed under a pressure of 0.2-0.4 MPa, and the reaction time is 2-6 h; Step S2, filtering the lithium bicarbonate solution at least twice to obtain a filtrate, and the lithium carbonate which is not completely carbonated can be returned to step S1; Preferably, the lithium bicarbonate solution is filtered through a filter membrane with a pore size of 1-5 microns for 2-3 times; Step S3, passing the filtrate into a resin for impurity removal; Preferably, the resin is a weak base anion exchange resin; Step S4, pyrolyzing the filtrate of step S3 at a certain temperature for a period of time to obtain lithium carbonate and a pyrolysis liquid, and the pyrolysis liquid is returned to step S1; Preferably, the lithium concentration in the filtrate is at least 8-16 g / L, and the pyrolysis is carried out at an environment of 90-100 DEG C for 30-120 min; Step S5, stirring and washing the lithium carbonate with water at a certain ratio to obtain high-purity lithium carbonate; Preferably, the liquid-solid ratio of lithium carbonate and water is 1.5:1-3:1, and the water temperature is 90-95℃; Step S6, after the high-purity lithium carbonate is slurried with water in a certain proportion, carbon dioxide is introduced to react under a certain temperature and pressure environment to obtain refined lithium bicarbonate solution; Preferably, the ratio of high-purity lithium carbonate and water is 1:8-1:20, the temperature is 20-40℃, carbon dioxide is introduced under a pressure of 0.2-0.4 MPa, and the reaction time is 2-6h; Step S7, the refined lithium bicarbonate solution is introduced into the jacketed reaction kettle 1, the refined lithium bicarbonate solution is continuously stirred, and hydrofluoric acid with a solute mass of 10%-40% is added dropwise, and a solid-liquid mixture is formed after reaction at a certain temperature; Preferably, the reaction temperature is 25-85℃, and the reaction time is 1-6h; Step S8, the solid-liquid mixture is filtered, the filtered water is returned to step S1, and the filtrate is washed and vacuum dried to obtain battery-grade lithium fluoride; Preferably, the filtrate is washed with 80-90℃ deionized water until the solution PH is 6-8, and then the filtrate is vacuum dried at a temperature of 80-100℃ and 100-150℃ in two steps to obtain battery-grade lithium fluoride.

[0029] In this embodiment, the process for preparing battery-grade lithium fluoride from industrial-grade lithium carbonate has the core advantages of overall balance in purity control, raw material utilization rate, cost optimization, safety, and scale adaptation. The process uses step-by-step carbonization and pyrolysis as the core purification logic. First, industrial-grade lithium carbonate is reacted with carbon dioxide to convert it into soluble lithium bicarbonate. Impurities such as calcium and magnesium ions are used to form insoluble substances to achieve preliminary separation. Then, lithium bicarbonate is pyrolyzed to generate high-purity lithium carbonate, while the lithium concentration is enriched. The pyrolysis liquid is recycled back to the initial step to avoid lithium loss. At least two micron filter membrane filtrations are used for physical impurity removal, and weak base anion exchange resin is used to adsorb anion impurities such as sulfates and chlorides. The impurity content is precisely controlled to meet the purity requirements of battery-grade lithium fluoride.

[0030] Please refer to Figures 1 to 11 The working principle of the equipment and process for preparing battery-grade lithium fluoride from industrial-grade lithium carbonate provided by the present application is as follows: Step S1, hydrofluoric acid is introduced into the storage tank 6, refined lithium bicarbonate solution is introduced into the jacketed reaction kettle 1 using the feed rod, then the driving motor 34 is started, the driving motor 34 rotates to drive the rotating shaft 31 to rotate, the rotating shaft 31 rotates to drive the stabilizing rod 33 and the stirring paddle 32 to rotate, thereby stirring the refined lithium bicarbonate solution; Step S2, when the rotating shaft 31 rotates, the two conical teeth 5 will drive the key bar 41 to rotate, the key bar 41 rotates and further drives the first eccentric wheel 42 to rotate, through the rotation of the first eccentric wheel 42, the reciprocating rod 45 is moved up and down under the action of the adjusting frame 46 and the rotating wheel 47, when the reciprocating rod 45 moves upwards, the piston 44 is pushed upwards, the hydrofluoric acid in the liquid outlet pipe 43 is pushed upwards, at this time, the height of the piston 44 is higher than the height of the communication position of the dropper 49 and the liquid outlet pipe 43, the dropper 49 will not drop hydrofluoric acid into the kettle, when the reciprocating rod 45 drives the piston 44 to move downwards, at this time, the height of the piston 44 is lower than the height of the communication position of the dropper 49 and the liquid outlet pipe 43, the dropper 49 will drop hydrofluoric acid into the kettle, through the continuous up and down movement of the reciprocating rod 45, the hydrofluoric acid is intermittently added into the kettle; Step S3, when the key bar 41 rotates, the second eccentric wheel 94 is driven to rotate, the second eccentric wheel 94 rotates and drives the guide rod 92 to move the pressing block 96 up and down through the driving frame 93; When the pressing block 96 moves downwards, the right side of the connecting plate 103 is pressed downwards, the rotating disc 102 rotates clockwise, the left side of the connecting plate 103 is raised upwards, and the scraper 105 is driven to move upwards through the connecting bracket 104, when the pressing block 96 moves upwards under the action of the tension spring 95, the pressing block 96 drives the connecting plate 103 to reset upwards, during the resetting process of the connecting plate 103, the connecting bracket 104 and the scraper 105 move downwards under the action of gravity, through the continuous rotation of the second eccentric wheel 94, the scraper 105 moves up and down, and the lithium fluoride crystals attached to the kettle wall are scraped off; Step S4, when the rotating shaft 31 rotates, the rotating shaft 113 is driven to rotate through the synchronous wheel 115 and the synchronous belt 116, the rotating shaft 113 rotates and drives the air suction fan 114 to rotate, the air suction fan 114 rotates and sucks the gas in the kettle, and the gas is discharged through the exhaust pipe 117; The exhaust pipe 117 is connected with a condenser made of PTFE, which condenses the volatile materials, the outlet of the condenser is connected with a tail gas absorption bottle, which contains sodium hydroxide solution, which is used to neutralize the trace HF acidic gas that may escape to ensure that the waste gas meets the emission standard.

[0031] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application, any equivalent structural transformation made under the concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. An apparatus for preparing lithium fluoride, an electrolyte feedstock, from industrial-grade lithium carbonate, characterized in that, Including a jacketed reaction kettle, a sealing cover, a stirring mechanism and a dropping mechanism; The stirring mechanism comprises a rotating shaft and a stirring paddle, the rotating shaft is vertically connected to the inner side of the sealing cover, and the stirring paddle is fixedly arranged at the bottom of the rotating shaft; The dropping mechanism comprises a key rod, a first eccentric wheel and a liquid outlet pipe, the key rod is horizontally arranged in the jacketed reaction kettle, the first eccentric wheel is connected with the key groove of the key rod, the top of the liquid outlet pipe is communicated with the sealing cover, the inner wall of the liquid outlet pipe is slidably connected with a piston, the bottom end of the piston is fixedly connected with a reciprocating rod, the bottom end of the reciprocating rod is fixedly connected with an adjusting frame, the inner side of the adjusting frame is provided with a rotating wheel, the bottom of the rotating wheel is matched with the top of the first eccentric wheel, the surface of the reciprocating rod is sleeved with a spring, and the liquid outlet pipe is communicated with a dropping tube.

2. The apparatus for producing lithium fluoride, a raw material for an electrolyte, from industrial-grade lithium carbonate according to claim 1, characterized by, The right end of the key rod and the surface of the rotating shaft are fixedly provided with tapered teeth, the two tapered teeth are meshed with each other, the top of the sealing cover is communicated with a storage tank, and the top of the storage tank is provided with a protective cover.

3. The apparatus for producing lithium fluoride, a raw material for an electrolyte of an industrial-grade lithium carbonate according to claim 1, characterized by, The surface of the rotating shaft is fixedly provided with a plurality of stabilizing rods, the plurality of stabilizing rods are fixedly connected with the stirring paddle, and the top of the sealing cover is provided with a driving motor for driving the rotating shaft to rotate.

4. The apparatus for producing lithium fluoride, a raw material for an electrolyte of an industrial-grade lithium carbonate according to claim 1, characterized by, The inner wall of the jacketed reaction kettle is fixedly provided with a mounting seat, the top of the mounting seat is fixedly provided with a driving mechanism, the driving mechanism comprises a mounting frame fixedly arranged at the top of the mounting seat, a guide rod is vertically and slidably connected in the mounting frame, the top end of the guide rod is fixedly provided with a driving frame, a second eccentric wheel is connected with the key groove in the surface of the key rod, the top of the driving frame is matched with the bottom of the second eccentric wheel, a tension spring is sleeved on the surface of the guide rod and in the mounting frame, the bottom of the tension spring is fixedly provided with a pressing block, the top of the pressing block is fixedly connected with the bottom end of the guide rod, and the key rod is rotationally connected with the mounting frame.

5. The apparatus for producing an electrolyte raw material lithium fluoride from an industrial-grade lithium carbonate according to claim 4, characterized by A wall scraping mechanism is slidably connected in the mounting frame, the wall scraping mechanism comprises a sliding frame slidably connected in the mounting frame, a rotating disc is rotationally connected in the sliding frame, a connecting plate is slidably connected in the rotating disc, the inner side of the pressing block is slidably connected with the inner side of the connecting plate, a connecting support is rotationally connected at the left side of the connecting plate, the connecting support is slidably connected with the inner sides of the mounting frame and the mounting seat, a scraper is fixedly arranged at the bottom of the connecting support, an adjusting screw is threadedly connected in the sliding frame, and the adjusting screw is rotationally connected with the jacketed reaction kettle.

6. The apparatus for producing lithium fluoride, a raw material for an electrolyte, from industrial-grade lithium carbonate according to claim 4, characterized by, An exhaust mechanism is fixedly arranged at the right side of the top of the mounting seat, the exhaust mechanism comprises a mounting sleeve fixedly arranged at the right side of the top of the mounting seat, a filter plate is fixedly arranged on the inner wall of the mounting sleeve, a rotating shaft is rotationally connected at the inner side of the filter plate, an air suction fan is fixedly arranged at the bottom end of the rotating shaft, tapered teeth are fixedly arranged on the surfaces of the rotating shaft and the rotating shaft, a synchronous belt is sleeved on the surfaces of the two synchronous wheels, and an exhaust pipe is communicated with the top of the mounting sleeve.

7. The apparatus for producing lithium fluoride, a raw material for an electrolyte, from industrial-grade lithium carbonate according to claim 1, characterized by, The surface of the rotating shaft is provided with two connecting sleeves, the two connecting sleeves are fixedly connected through bolts, one side away from each other of the two connecting sleeves is fixedly provided with a connecting plate, and the surface of the connecting plate is fixedly provided with a defoaming support.

8. The apparatus for producing lithium fluoride, a raw material for an electrolyte, from industrial-grade lithium carbonate according to claim 4, characterized by, The inside of the mounting seat is provided with a composite PH electrode, the top of the sealing cover is provided with a sound-light alarm, the surface of the jacketed reaction kettle is communicated with a feeding pipe, and the bottom of the jacketed reaction kettle is communicated with a discharging pipe.

9. A process for the preparation of lithium fluoride, a raw material for electrolyte, from industrial grade lithium carbonate, characterized by, The process for preparing the electrolyte raw material lithium fluoride comprises the equipment for preparing the electrolyte raw material lithium fluoride according to any one of claims 1-8 and the following steps: Step S1, mixing industrial-grade lithium carbonate and water, then passing carbon dioxide to react for a certain time to obtain a lithium bicarbonate solution with a PH value of 8-14; Step S2, filtering the lithium bicarbonate solution for at least twice to obtain a filtrate, wherein the lithium carbonate that is not completely carbonated can be returned to step S1; Step S3, passing the filtrate into a resin for impurity removal; Step S4, pyrolyzing the filtrate of step S3 at a certain temperature for a period of time to obtain lithium carbonate and a pyrolysis liquid, and the pyrolysis liquid is returned to step S1; Step S5, stirring and washing the lithium carbonate with water in a certain proportion to obtain high-purity lithium carbonate; Step S6, after slurry preparation of the high-purity lithium carbonate with water in a certain proportion, passing carbon dioxide into the slurry under a certain temperature and pressure environment to obtain a refined lithium bicarbonate solution; Step S7, passing the refined lithium bicarbonate solution into a jacketed reaction kettle, continuously stirring the refined lithium bicarbonate solution, and dropping in a solute mass of 10%-40% hydrofluoric acid drop by drop, to form a solid-liquid mixture after reaction at a certain temperature; Step S8, filtering the solid-liquid mixture, returning the filter water to step S1, washing the filter and vacuum drying to obtain battery-grade lithium fluoride.

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