Apparatus for extracting battery-grade lithium carbonate from lepidolite and co-production of calcium sulfate whisker process

Abstract

The application provides a device for extracting battery-grade lithium carbonate from lepidolite and a co-production calcium sulfate whisker process, relates to the technical field of lithium battery raw material extraction, and comprises a lithium extraction kettle, a kettle cover, a stirring mechanism, a wall sticking prevention mechanism and a mounting disc. The stirring mechanism comprises a rotating shaft which is vertically and rotatably connected to the inner side of the kettle cover. A stirring paddle is fixed to the surface of the rotating shaft and located in the interior of the lithium extraction kettle. A driving motor is arranged on the top of the kettle cover and used for driving the rotating shaft to rotate. The first pulley, the reciprocating frame and the reciprocating rod are used to make the vibrating block reciprocate under the action of the first spring, to gently knock the kettle wall, to make the kettle wall vibrate slightly, to prevent the generated lithium carbonate microcrystal nucleus from adhering to the kettle wall, to improve the recovery rate of lithium carbonate, and to avoid the problems of scale formation on the kettle wall due to the adhesion of lithium carbonate, reduced heating efficiency, temperature control failure and influence on reaction stability.

Description

Technical Field

[0001] This invention relates to the field of lithium battery raw material extraction, and in particular to equipment for extracting battery-grade lithium carbonate from lepidolite and a process for co-producing calcium sulfate whiskers. Background Technology

[0002] Lithium carbonate is the fundamental lithium source and starting point for manufacturing almost all types of cathode materials for lithium-ion batteries. Through high-temperature solid-state chemical reactions, it reacts with other metal compounds to synthesize electrochemically active cathode materials, earning it the reputation of being the "cornerstone" of the lithium battery industry. Lithium mica, as an important lithium-containing mineral, is crucial for the diversification and security of the global lithium battery industry supply chain through its development and utilization.

[0003] In related technologies, the process of extracting battery-grade lithium carbonate from lepidolite requires the addition of sodium carbonate solution under heating conditions. However, existing equipment for extracting battery-grade lithium carbonate from lepidolite is not conducive to preventing the adhesion and growth of lithium carbonate microcrystals on the reactor wall. During the preparation process, the temperature in the reactor wall area is the highest, and a large number of lithium carbonate microcrystals preferentially form on the reactor wall surface and adhere firmly to it. This directly leads to a decrease in the recovery rate of lithium carbonate, a sharp drop in heat transfer efficiency, failure of temperature control, and affects the stability of the reaction.

[0004] Therefore, it is necessary to provide equipment for extracting battery-grade lithium carbonate from lepidolite and a process for co-producing calcium sulfate whiskers to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides equipment for extracting battery-grade lithium carbonate from lepidolite and a process for co-producing calcium sulfate whiskers, which solves the problem that existing equipment for extracting battery-grade lithium carbonate from lepidolite is not easy to avoid the adhesion and growth of lithium carbonate microcrystal nuclei on the reactor wall during use.

[0006] To solve the above-mentioned technical problems, the present invention provides an apparatus for extracting battery-grade lithium carbonate from lepidolite, comprising a lithium extraction vessel, a vessel lid, a stirring mechanism, an anti-sticking mechanism, and a mounting plate;

[0007] The stirring mechanism includes a rotating shaft that is vertically rotatably connected to the inside of the lid, and a stirring paddle is fixed on the surface of the rotating shaft and inside the lithium extraction vessel. A drive motor for driving the rotating shaft to rotate is provided on the top of the lid.

[0008] The anti-sticking mechanism includes a cam with a keyway connected to the surface of a rotating shaft. A mounting frame is fixedly mounted on the right side of the top of the mounting plate. A reciprocating frame is slidably connected inside the mounting frame. A first rotating wheel is rotatably connected to the inner side of the left side of the reciprocating frame. The first rotating wheel is in contact with the cam. A reciprocating rod is fixedly mounted on the right side of the reciprocating frame. The circumferential side of the reciprocating rod is slidably connected to the inner side of the mounting frame. A vibration block is fixedly mounted at the right end of the reciprocating rod. A first spring is sleeved on the surface of the reciprocating rod inside the mounting frame.

[0009] Preferably, the lithium extraction vessel and the vessel cover are connected by bolts for sealing. The mounting frame has a guide groove inside that works with the reciprocating frame. When the cam rotates, the reciprocating frame, reciprocating rod and vibrating block move back and forth left and right through the cooperation of the first rotating wheel and the first spring, causing the vessel wall to vibrate slightly.

[0010] Preferably, a feeding mechanism is fixedly provided on the top of the inner wall of the vessel lid. The feeding mechanism includes a mounting shell fixedly provided on the top of the inner wall of the vessel lid. A rotating shaft is vertically rotatably connected inside the mounting shell. Pulleys are fixedly provided on the bottom end and the circumferential side of the rotating shaft. A belt is sleeved on the surface of the two pulleys.

[0011] Preferably, a rotating wheel is fixedly provided on the circumferential side of the rotating shaft and inside the mounting housing. Three mounting brackets are arranged in a circular array on the circumferential side of the rotating wheel. The bottom of each of the three mounting brackets is rotatably connected to a drive wheel by bolts. A feed hose is provided on the inner wall of the mounting housing. When the rotating wheel rotates, the drive wheel will contact the feed hose and squeeze the feed hose.

[0012] Preferably, the bottom of the mounting plate is fixedly provided with a swing dosing mechanism. The swing dosing mechanism includes two rotating brackets fixedly disposed at the bottom of the mounting plate. The dosing pipe is rotatably connected inside the two rotating brackets. Multiple nozzles are connected to the surface of the dosing pipe. A swing gear is fixedly disposed on the peripheral side of the dosing pipe. A slider is slidably connected to the inner side of the mounting plate. A toothed assembly is provided at the bottom of the slider. The toothed assembly meshes with the swing gear. The slider is fixedly connected to the reciprocating frame by bolts. The bottom end of the feed hose is connected to the dosing pipe.

[0013] Preferably, a seed crystal adding mechanism is fixedly provided on the left side of the top of the mounting plate. The seed crystal adding mechanism includes a sliding frame fixedly provided on the left side of the top of the mounting plate. A feeding plate is slidably connected to the inner side of the sliding frame. A second spring is provided on the left side of the feeding plate. A second rotating wheel is rotatably connected to the right side of the top of the feeding plate. The second rotating wheel is in contact with a cam. A material box is provided on the top of the lid. A discharge pipe is connected to the bottom of the material box.

[0014] Preferably, the bottom of the discharge pipe is in contact with the top of the feeding plate, and both the feeding plate and the mounting plate have feeding slots on their inner sides.

[0015] Preferably, the right side of the lithium extraction vessel is connected to an inlet pipe, the bottom of the lithium extraction vessel is connected to an outlet pipe, the top of the vessel cover is connected to an exhaust pipe, and four support seats are arranged in a circular array on the periphery of the lithium extraction vessel, with a support frame at the bottom of the four support seats.

[0016] The process for extracting battery-grade lithium carbonate and co-producing calcium sulfate whiskers from lepidolite includes the following steps:

[0017] Step S1: Crush the lepidolite ore to a particle size of <2mm, and grind it to 60-80μm using a vibratory grinder to ensure that more than 90% of the particles pass through.

[0018] Step S2: Mix lepidolite and calcium oxide in a certain ratio in a corundum crucible, then place it in a muffle furnace and heat it from room temperature to 1000-1400℃ at a certain heating rate for 30-40 minutes. Remove the crucible immediately after the thermal activation process is complete.

[0019] Step S3: Quickly pour the activated slag into a pre-prepared iron bucket containing 10 liters of deionized water at room temperature for cooling. Simultaneously turn on the mechanical stirrer, control the stirring speed at 300 rpm, and continue stirring for 15 minutes to ensure that the slag is evenly dispersed and cooled to room temperature, thereby obtaining water-quenched slag. The slow-cooled slag in the furnace is obtained by thermally activating it and then cooling it at a certain rate.

[0020] Step S4: After cooling, place the slag in an electric heating drying oven to dry, and grind it to 60-90 micrometers using a sealed experimental mill. The leaching process is carried out in a water bath. The finely ground slag at room temperature is mixed with the leaching agent that has reached the specified temperature in a beaker at a certain liquid-solid ratio. The leaching solution and residue are obtained by magnetic stirring. The filter residue is washed twice with hot water, and the washing solution is added to the filtrate.

[0021] Step S5: Slowly add calcium carbonate powder to the leachate, adjust the pH to 5.5, and stir to allow Fe³⁺ to form. + Al³ + Hydroxide precipitate is formed, and the precipitate is removed by filtration. The filtrate mainly contains Li. + 、Rb + Ca² + Mg² + Add sodium carbonate solution to the filtrate, with a molar concentration of 1 mol / L, to make Ca²⁺... + Mg² + The precipitate is carbonate. After filtration, ammonium oxalate solution is added dropwise to the clear liquid to test whether calcium and magnesium have been completely removed. The molar concentration is 0.1 mol / L.

[0022] Li adsorption using ion exchange resin + 、Rb + Elute with 2 mol / L hydrochloric acid, collect the eluent, and concentrate by evaporation;

[0023] Step S6: Heat the mixed solution obtained in step S5 to above 90°C. Under vigorous stirring, slowly add an excess of preheated saturated sodium carbonate solution. Lithium and rubidium in the solution will precipitate together to form a mixed solid of lithium carbonate and rubidium carbonate. At a high temperature above 90°C, vacuum filter is performed while hot. Most of the rubidium carbonate will dissolve in the hot water and be discharged with the filtrate, while lithium carbonate will be retained as a filter cake. The filter cake is thoroughly washed with hot deionized water above 80°C until the washing solution is tested with silver nitrate and no chloride ions are found.

[0024] Step S7: Mix the leaching residue with deionized water at a certain liquid-solid ratio, add sulfuric acid to adjust the pH value to 5, stir for a certain time, and then add sodium dodecylbenzenesulfonate as a surfactant.

[0025] Step S8: Transfer the slurry to a high-pressure reactor and react at 90-130℃ for 4 hours, maintaining a stirring rate of 200-400 rpm during the reaction. After the reaction is complete, allow it to cool naturally to room temperature and filter to collect the white whisker product.

[0026] Compared with related technologies, the equipment for extracting battery-grade lithium carbonate from lepidolite and the process for co-producing calcium sulfate whiskers provided by this invention have the following advantages:

[0027] When the lithium extraction vessel heats the mixed solution to above 90°C and adds sodium carbonate solution, a drive motor drives a rotating shaft and a stirring paddle to mix the mixed solution and sodium carbonate solution, generating lithium carbonate microcrystal nuclei. As the rotating shaft rotates, it simultaneously drives a cam to rotate. Through the first rotating wheel, reciprocating frame, and reciprocating rod, under the action of the first spring, the vibrating block moves back and forth, gently tapping the vessel wall and causing slight vibration. This prevents the generated lithium carbonate microcrystal nuclei from adhering to the vessel wall, thereby improving the lithium carbonate recovery rate. Furthermore, it avoids scaling on the vessel wall caused by lithium carbonate adhesion, which can reduce heating efficiency, cause temperature control failure, and affect reaction stability. It also prevents scaling from contaminating subsequent products and causing the final product to be substandard. Attached Figure Description

[0028] 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.

[0029] Figure 1 The optimal structural schematic diagram provided for this invention;

[0030] Figure 2 This is a schematic diagram of the cross-sectional view of the lithium extraction vessel provided by the present invention;

[0031] Figure 3 for Figure 2 The diagram shown is a structural schematic of the bottom view of the lithium extraction vessel.

[0032] Figure 4 This is a schematic diagram of the stirring mechanism provided by the present invention;

[0033] Figure 5 This is a schematic diagram of the anti-adhesion mechanism provided by the present invention;

[0034] Figure 6 for Figure 5 The diagram shows the state in which the rotating shaft drives the cam to rotate, causing the reciprocating frame, reciprocating rod and vibrating block to move to the right.

[0035] Figure 7 This is a schematic diagram of the feeding mechanism provided by the present invention;

[0036] Figure 8 for Figure 7 The diagram shows a structural schematic of the bottom view of the feeding mechanism.

[0037] Figure 9 This is a schematic diagram of the oscillating dosing mechanism provided by the present invention;

[0038] Figure 10 for Figure 9 The diagram shows the state in which the slider and tooth assembly move to the right, causing the oscillating gear to drive the dosing tube to rotate.

[0039] Figure 11 A schematic diagram of the seed crystal addition mechanism provided by the present invention;

[0040] Figure 12 for Figure 11 The diagram shows the state in which the rotating shaft drives the cam to rotate, and the feeding plate slides to the right under the action of the second spring.

[0041] Figure 13 This is a schematic diagram of the process flow provided by the present invention.

[0042] Explanation of icon numbers:

[0043] 1. Lithium extraction vessel; 2. Vessel lid;

[0044] 3. Stirring mechanism; 31. Rotating shaft; 32. Stirring paddle; 33. Drive motor;

[0045] 4. Anti-sticking mechanism; 41. Cam; 42. Mounting bracket; 43. Reciprocating frame; 44. First rotating wheel; 45. Reciprocating rod; 46. Vibrating block; 47. First spring;

[0046] 5. Installation disk;

[0047] 6. Feeding mechanism; 61. Mounting housing; 62. Rotating shaft; 63. Pulley; 64. Belt; 65. Rotating wheel; 66. Mounting bracket; 67. Drive wheel; 68. Feed hose;

[0048] 7. Oscillating dosing mechanism; 71. Rotating bracket; 72. Dosing pipe; 73. Nozzle; 74. Oscillating gear; 75. Sliding block; 76. Gear assembly;

[0049] 8. Seed crystal addition mechanism; 81. Sliding frame; 82. Feeding plate; 83. Second spring; 84. Second rotating wheel; 85. Material box; 86. Discharge pipe;

[0050] 9. Inlet pipe; 10. Drain pipe; 11. Exhaust pipe; 12. Support base; 13. Support frame. Detailed Implementation

[0051] 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.

[0052] This invention provides an apparatus for extracting battery-grade lithium carbonate from lepidolite.

[0053] First embodiment:

[0054] Please see Figures 1 to 6 An apparatus for extracting battery-grade lithium carbonate from lepidolite, comprising a lithium extraction vessel 1, a vessel lid 2, a stirring mechanism 3, an anti-sticking mechanism 4, and a mounting plate 5;

[0055] The stirring mechanism 3 includes a rotating shaft 31 that is vertically rotatably connected to the inside of the lid 2. A stirring paddle 32 is fixed on the surface of the rotating shaft 31 and inside the lithium extraction vessel 1. A drive motor 33 for driving the rotating shaft 31 to rotate is provided on the top of the lid 2.

[0056] The anti-sticking mechanism 4 includes a cam 41 with a keyway connected to the surface of the rotating shaft 31. A mounting frame 42 is fixedly mounted on the right side of the top of the mounting plate 5. A reciprocating frame 43 is slidably connected inside the mounting frame 42. A first rotating wheel 44 is rotatably connected to the inner side of the left side of the reciprocating frame 43. The first rotating wheel 44 is in contact with the cam 41. A reciprocating rod 45 is fixedly mounted on the right side of the reciprocating frame 43. The circumferential side of the reciprocating rod 45 is slidably connected to the inner side of the mounting frame 42. A vibration block 46 is fixedly mounted at the right end of the reciprocating rod 45. A first spring 47 is sleeved on the surface of the reciprocating rod 45 and inside the mounting frame 42.

[0057] The lithium extraction vessel 1 and the vessel cover 2 are connected by bolts for sealing. The mounting frame 42 has a guide groove inside that works with the reciprocating frame 43. When the cam 41 rotates, the reciprocating frame 43, the reciprocating rod 45 and the vibrating block 46 move back and forth left and right through the cooperation of the first rotating wheel 44 and the first spring 47, causing the vessel wall to vibrate slightly.

[0058] Please combine Figure 4 Start the drive motor 33. The drive motor 33 rotates and drives the rotating shaft 31 to rotate. The rotating shaft 31 rotates and drives the stirring paddle 32 to rotate. The rotation of the stirring paddle 32 mixes the mixed solution and the sodium carbonate solution.

[0059] Please combine Figure 5 and Figure 6 When the rotating shaft 31 rotates, it will simultaneously drive the cam 41 to rotate. When the protruding part of the cam 41 contacts the first rotating wheel 44, the first rotating wheel 44 will push the reciprocating frame 43 to move to the right inside the mounting frame 42. The rightward movement of the mounting frame 42 will drive the reciprocating rod 45 to move to the right. The reciprocating rod 45 will drive the vibrating block 46 to gently tap the reactor wall, causing the reactor wall to vibrate slightly. When the sodium carbonate solution is added to the mixed solution, a large number of lithium carbonate microcrystal nuclei will quickly precipitate because the temperature of the reactor wall area is the highest. Through the vibration of the reactor wall, the lithium carbonate microcrystal nuclei will fall off the reactor wall.

[0060] Furthermore, as the rotating shaft 31 drives the cam 41 to continue rotating, the position of the cam 41 protrusion changes. Under the action of the first spring 47, the reciprocating frame 43 slides to the left on the inner side of the mounting frame 42, and then drives the vibrating block 46 to move to the left through the reciprocating rod 45. The rotating shaft 31 drives the cam 41 to rotate continuously, so that the reciprocating frame 43 moves back and forth, driving the vibrating block 46 to continuously tap the vessel wall slightly.

[0061] Preferably, the lithium extraction vessel 1 has a heating function, which can heat the mixed solution.

[0062] In this embodiment, when the lithium extraction vessel 1 heats the mixed solution to above 90°C and adds sodium carbonate solution to the mixed solution, the drive motor 33 drives the rotating shaft 31 and the stirring paddle 32 to rotate, mixing the mixed solution and the sodium carbonate solution to generate lithium carbonate microcrystal nuclei. When the rotating shaft 31 rotates, it simultaneously drives the cam 41 to rotate. Through the first rotating wheel 44, the reciprocating frame 43 and the reciprocating rod 45, under the action of the first spring 47, the vibrating block 46 moves back and forth, gently tapping the vessel wall and causing slight vibration. This prevents the generated lithium carbonate microcrystal nuclei from adhering to the vessel wall, thereby improving the lithium carbonate recovery rate. It also avoids the problem of scale buildup on the vessel wall caused by lithium carbonate adhesion, which would reduce heating efficiency, cause temperature control failure, and affect reaction stability. Furthermore, it prevents scale buildup from contaminating subsequent products and causing the final product to be unqualified.

[0063] Second embodiment:

[0064] Please see Figures 7 to 10 The top of the inner wall of the vessel lid 2 is fixedly provided with a feeding mechanism 6. The feeding mechanism 6 includes a mounting shell 61 fixedly provided on the top of the inner wall of the vessel lid 2. The mounting shell 61 is vertically rotatably connected to a rotating shaft 62. The bottom end of the rotating shaft 62 and the peripheral side of the rotating shaft 31 are both fixedly provided with pulleys 63. The surfaces of the two pulleys 63 are fitted with belts 64.

[0065] A rotating wheel 65 is fixedly installed on the circumferential side of the rotating shaft 62 and inside the mounting housing 61. Three mounting brackets 66 are arranged in a circular array on the circumferential side of the rotating wheel 65. The bottom of each of the three mounting brackets 66 is rotatably connected to a drive wheel 67 by bolts. A feed hose 68 is provided on the inner wall of the mounting housing 61. When the rotating wheel 65 rotates, the drive wheel 67 will contact the feed hose 68 and squeeze the feed hose 68.

[0066] The bottom of the mounting plate 5 is fixedly provided with a swing dosing mechanism 7. The swing dosing mechanism 7 includes two rotating brackets 71 fixedly provided at the bottom of the mounting plate 5. The dosing pipe 72 is rotatably connected inside the two rotating brackets 71. Multiple nozzles 73 are connected to the surface of the dosing pipe 72. A swing gear 74 is fixedly provided on the peripheral side of the dosing pipe 72. A slider 75 is slidably connected to the inner side of the mounting plate 5. A toothed assembly 76 is provided at the bottom of the slider 75. The toothed assembly 76 meshes with the swing gear 74. The slider 75 is fixedly connected to the reciprocating frame 43 by bolts. The bottom end of the feed hose 68 is connected to the dosing pipe 72.

[0067] Please combine Figure 7 and Figure 8When the rotating shaft 31 rotates, the belt 63 and the pulley 64 will simultaneously drive the rotating shaft 62 to rotate. The rotation of the rotating shaft 62 will then drive the rotating wheel 65 to rotate. The rotation of the rotating wheel 65 will drive multiple mounting brackets 66 and drive wheels 67 to rotate. Through the periodic squeezing and releasing of the feed hose 68 by the multiple drive wheels 67, the sodium carbonate solution is delivered to the dosing pipe 72.

[0068] Please combine Figure 9 and Figure 10 When the reciprocating frame 43 moves to the right, the bolts will simultaneously drive the slider 75 and the toothed assembly 76 to move to the right. The toothed assembly 76 moving to the right will drive the oscillating gear 74 to rotate clockwise. The clockwise rotation of the oscillating gear 74 will then drive the dosing pipe 72 and multiple nozzles 73 to rotate clockwise.

[0069] Furthermore, when the reciprocating frame 43 moves to the left, it will simultaneously drive the slider 75 and the toothed assembly 76 to move to the left via the bolt. The leftward movement of the toothed assembly 76 drives the oscillating gear 74 to rotate counterclockwise. The counterclockwise rotation of the oscillating gear 74 drives the dosing pipe 72 and multiple nozzles 73 to rotate counterclockwise, resetting the position of the nozzles 73. Through the reciprocating movement of the slider 75 and the toothed assembly 76, the dosing pipe 72 drives the multiple nozzles 73 to reciprocate spraying sodium carbonate solution.

[0070] Preferably, the two pulleys 63 have different diameters, with the pulley 63 on the surface of the rotating shaft 62 being larger. When the pulley 63 on the surface of the rotating shaft 31 rotates several times, the pulley 63 on the surface of the rotating shaft 62 will rotate one revolution, thereby achieving the effect of vigorous stirring of the mixed solution and slow addition of saturated sodium carbonate solution.

[0071] Preferably, the inner side of the mounting bracket 66 is provided with a groove for use with bolts, for slight adjustment of the contact position between the drive wheel 67 and the feed hose 68.

[0072] In this embodiment, when the rotating shaft 31 drives the stirring paddle 32 to vigorously stir the mixed solution, the belt 63 and the pulley 64 drive the rotating shaft 62 and the rotating wheel 65 to rotate. The rotating wheel 65 drives multiple drive wheels 67 to periodically squeeze and release the feed hose 68 through the mounting bracket 66, thereby transporting the sodium carbonate solution into the dosing pipe 72.

[0073] When the reciprocating frame 43 moves back and forth, it drives the slider 75 and the toothed assembly 76 to move back and forth. In turn, the oscillating gear 74 drives the dosing tube 72 and multiple nozzles 73 to oscillate back and forth, adding sodium carbonate solution to the mixed solution. Compared with the traditional fixed tube flow, the sodium carbonate solution can be uniformly contacted with the mixed solution in the form of fine droplets, which is conducive to the formation of larger and more uniform lithium carbonate crystals. Importantly, the addition by oscillating the dosing tube 72 and multiple nozzles 73 can avoid the rapid formation of a large number of lithium carbonate microcrystal nuclei in a local area, reducing the probability of lithium carbonate microcrystal nuclei adhering to the reactor wall.

[0074] Third embodiment:

[0075] Please see Figure 1 , Figure 11 and Figure 12 A seed crystal adding mechanism 8 is fixedly provided on the left side of the top of the mounting plate 5. The seed crystal adding mechanism 8 includes a sliding frame 81 fixedly provided on the left side of the top of the mounting plate 5. A feeding plate 82 is slidably connected to the inner side of the sliding frame 81. A second spring 83 is provided on the left side of the feeding plate 82. A second rotating wheel 84 is rotatably connected to the right side of the top of the feeding plate 82. The second rotating wheel 84 is in contact with the cam 41. A material box 85 is provided on the top of the lid 2. A discharge pipe 86 is connected to the bottom of the material box 85.

[0076] The bottom of the discharge pipe 86 is in contact with the top of the feeding plate 82, and both the feeding plate 82 and the mounting plate 5 have feeding slots on their inner sides.

[0077] The right side of the lithium extraction vessel 1 is connected to an inlet pipe 9, the bottom of the lithium extraction vessel 1 is connected to an outlet pipe 10, the top of the vessel cover 2 is connected to an exhaust pipe 11, and four support seats 12 are arranged in a ring array on the periphery of the lithium extraction vessel 1, and a support frame 13 is arranged at the bottom of the four support seats 12.

[0078] Please combine Figure 11 and Figure 12 When the rotating shaft 31 drives the cam 41 to rotate, and the protruding part of the cam 41 contacts the second rotating wheel 84, the second rotating wheel 84 will drive the feeding plate 82 to move to the left inside the sliding frame 81, so that the seed crystals in the material box 85 enter the lithium extraction vessel 1 through the discharge pipe 86 and the feeding trough in the feeding plate 82.

[0079] Furthermore, when the rotating shaft 31 drives the cam 41 to rotate, and the protruding position of the cam 41 disengages from the second rotating wheel 84, the feeding plate 82 will move to the right under the action of the second spring 83. The feeding groove in the feeding plate 82 and the discharge pipe 86 will no longer overlap, thereby stopping the addition of seed crystals to the lithium extraction vessel 1. The rotating shaft 31 drives the cam 41 to rotate continuously, so that seed crystals can be added to the lithium extraction vessel 1 intermittently.

[0080] In this embodiment, when the rotating shaft 31 drives the cam 41 to rotate continuously, the feeding plate 82 will reciprocate within the sliding frame 81 under the cooperation of the second spring 83 and the cam 41, thereby intermittently feeding seed crystals into the lithium extraction vessel 1 through the material box 85 and the discharge pipe 86. The fed seed crystals can provide nucleation sites, promote the formation of larger and more uniform crystals, and reduce the generation of lithium carbonate microcrystal nuclei.

[0081] The present invention also provides a process for extracting battery-grade lithium carbonate from lepidolite and co-producing calcium sulfate whiskers.

[0082] Please see Figure 13 The process for extracting battery-grade lithium carbonate and co-producing calcium sulfate whiskers from lepidolite includes the following steps:

[0083] Step S1: Crush the lepidolite ore to a particle size of <2mm, and grind it to 60-80μm using a vibratory grinder to ensure that more than 90% of the particles pass through.

[0084] Step S2: Mix lepidolite and calcium oxide in a certain ratio in a corundum crucible, then place it in a muffle furnace and heat it from room temperature to 1000-1400℃ at a certain heating rate for 30-40 minutes. Remove the crucible immediately after the thermal activation process is complete.

[0085] Step S3: Quickly pour the activated slag into a pre-prepared iron bucket containing 10 liters of deionized water at room temperature for cooling. Simultaneously turn on the mechanical stirrer, control the stirring speed at 300 rpm, and continue stirring for 15 minutes to ensure that the slag is evenly dispersed and cooled to room temperature, thereby obtaining water-quenched slag. The slow-cooled slag in the furnace is obtained by thermally activating it and then cooling it at a certain rate.

[0086] Step S4: After cooling, place the slag in an electric heating drying oven to dry, and grind it to 60-90 micrometers using a sealed experimental mill. The leaching process is carried out in a water bath. The finely ground slag at room temperature is mixed with the leaching agent that has reached the specified temperature in a beaker at a certain liquid-solid ratio. The leaching solution and residue are obtained by magnetic stirring. The filter residue is washed twice with hot water, and the washing solution is added to the filtrate.

[0087] Step S5: Slowly add calcium carbonate powder to the leachate, adjust the pH to 5.5, and stir to allow Fe³⁺ to form. + Al³ + Hydroxide precipitate is formed, and the precipitate is removed by filtration. The filtrate mainly contains Li. + 、Rb + Ca² + Mg² + Add sodium carbonate solution to the filtrate, with a molar concentration of 1 mol / L, to make Ca²⁺... + Mg²+ The precipitate is carbonate. After filtration, ammonium oxalate solution is added dropwise to the clear liquid to test whether calcium and magnesium have been completely removed. The molar concentration is 0.1 mol / L.

[0088] Li adsorption using ion exchange resin + 、Rb + Elute with 2 mol / L hydrochloric acid, collect the eluent, and concentrate by evaporation;

[0089] Step S6: Heat the mixed solution obtained in step S5 to above 90°C. Under vigorous stirring, slowly add an excess of preheated saturated sodium carbonate solution. Lithium and rubidium in the solution will precipitate together to form a mixed solid of lithium carbonate and rubidium carbonate. At a high temperature above 90°C, vacuum filter is performed while hot. Most of the rubidium carbonate will dissolve in the hot water and be discharged with the filtrate, while lithium carbonate will be retained as a filter cake. The filter cake is thoroughly washed with hot deionized water above 80°C until the washing solution is tested with silver nitrate and no chloride ions are found.

[0090] Step S7: Mix the leaching residue with deionized water at a certain liquid-solid ratio, add sulfuric acid to adjust the pH value to 5, stir for a certain time, and then add sodium dodecylbenzenesulfonate as a surfactant.

[0091] Step S8: Transfer the slurry to a high-pressure reactor and react at 90-130℃ for 4 hours, maintaining a stirring rate of 200-400 rpm during the reaction. After the reaction is completed, allow it to cool naturally to room temperature and filter to collect the white whisker product.

[0092] Preferably, in step S8, the whiskers are washed three times with deionized water and dried at 80°C for 2 hours.

[0093] Preferably, the rubidium-containing stock solution generated in step S6 can be recovered as rubidium chloride product by adding a recovery process, thus solving the problem of its disposal.

[0094] Preferably, step S5 involves evaporation and concentration to Li + Concentration approximately 10 g / L, Rb + The concentration is approximately 1 g / L.

[0095] In this embodiment, lepidolite is treated by a process that combines thermal activation and sulfuric acid leaching. During the thermal activation process, the crystal structure of lepidolite is destroyed and transformed into an activated state. Subsequently, water quenching forces the activated slag to maintain this state, which is beneficial to the subsequent acid leaching process.

[0096] Furthermore, reprocessing the leaching residue through hydrothermal reaction to prepare calcium sulfate whiskers with high aspect ratio not only reduces the generation of solid waste but also enhances the economic value of the process.

[0097] Please refer to the reference again. Figures 1 to 12The working principle of the device for extracting battery-grade lithium carbonate from lepidolite provided by this invention is as follows:

[0098] Step S1: The mixed solution generated in step S5 is transported into the lithium extraction vessel 1 through the liquid inlet pipe 9. Then, the mixed solution is heated to above 90°C using the lithium extraction vessel 1. The drive motor 33 is then started. The drive motor 33 rotates and drives the rotating shaft 31 to rotate. The rotating shaft 31 rotates and drives the stirring paddle 32 to quickly stir the mixed solution.

[0099] In step S2, when the rotating shaft 31 rotates, the belt 63 and pulley 64 simultaneously drive the rotating shaft 62 to rotate. The rotation of the rotating shaft 62 then drives the rotating wheel 65 to rotate. The rotation of the rotating wheel 65 drives multiple mounting brackets 66 and drive wheels 67 to rotate. The multiple drive wheels 67 periodically squeeze and release the feed hose 68 to deliver the sodium carbonate solution into the dosing pipe 72, and the preheated sodium carbonate solution is sprayed into the mixed solution through multiple nozzles 73.

[0100] In step S3, when the rotating shaft 31 rotates, it will simultaneously drive the cam 41 to rotate. When the protruding position of the cam 41 contacts the first rotating wheel 44, the first rotating wheel 44 will push the reciprocating frame 43 to move to the right inside the mounting frame 42. The rightward movement of the mounting frame 42 will drive the reciprocating rod 45 to move to the right. The reciprocating rod 45 will drive the vibrating block 46 to gently tap the reactor wall, causing the reactor wall to vibrate slightly. Through the vibration of the reactor wall, the lithium carbonate microcrystal nuclei will fall off the reactor wall.

[0101] When the rotating shaft 31 drives the cam 41 to continue rotating, after the position of the cam 41 protrusion changes, under the action of the first spring 47, the reciprocating frame 43 slides to the left on the inner side of the mounting frame 42, and then drives the vibrating block 46 to move to the left through the reciprocating rod 45. The rotating shaft 31 drives the cam 41 to continue rotating, and by using the reciprocating frame 43 to move back and forth, the vibrating block 46 continuously taps the vessel wall slightly.

[0102] In step S4, when the reciprocating frame 43 moves to the right, the bolt will simultaneously drive the slider 75 and the toothed assembly 76 to move to the right. The toothed assembly 76 moving to the right will drive the oscillating gear 74 to rotate clockwise. The clockwise rotation of the oscillating gear 74 will drive the dosing pipe 72 and multiple nozzles 73 to rotate clockwise.

[0103] When the reciprocating frame 43 moves to the left, it will simultaneously drive the slider 75 and the toothed assembly 76 to move to the left via the bolt. The leftward movement of the toothed assembly 76 will drive the oscillating gear 74 to rotate counterclockwise. The counterclockwise rotation of the oscillating gear 74 will drive the dosing pipe 72 and multiple nozzles 73 to rotate counterclockwise, resetting the position of the nozzles 73. The slider 75 and the toothed assembly 76 will reciprocate, thereby causing the dosing pipe 72 to drive the multiple nozzles 73 to spray sodium carbonate solution reciprocally.

[0104] Step S5: When the rotating shaft 31 drives the cam 41 to rotate and the cam 41 protrusion contacts the second rotating wheel 84, the second rotating wheel 84 will drive the feeding plate 82 to move to the left inside the sliding frame 81, so that the seed crystals in the material box 85 enter the lithium extraction vessel 1 through the discharge pipe 86 and the feeding groove in the feeding plate 82.

[0105] When the rotating shaft 31 drives the cam 41 to rotate, and the protruding position of the cam 41 disengages from the second rotating wheel 84, the feeding plate 82 will move to the right under the action of the second spring 83. The feeding groove in the feeding plate 82 and the discharge pipe 86 will no longer overlap, thereby stopping the addition of seed crystals to the lithium extraction vessel 1. By driving the cam 41 to rotate continuously through the rotating shaft 31, seed crystals can be intermittently added to the lithium extraction vessel 1.

[0106] 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 extracting battery-grade lithium carbonate from lepidolite, characterized in that, Includes lithium extraction vessel, vessel lid, stirring mechanism, anti-sticking mechanism and mounting plate; The stirring mechanism includes a rotating shaft that is vertically rotatably connected to the inside of the lid, and a stirring paddle is fixed on the surface of the rotating shaft and inside the lithium extraction vessel. A drive motor for driving the rotating shaft to rotate is provided on the top of the lid. The anti-sticking mechanism includes a cam with a keyway connected to the surface of a rotating shaft. A mounting frame is fixedly mounted on the right side of the top of the mounting plate. A reciprocating frame is slidably connected inside the mounting frame. A first rotating wheel is rotatably connected to the inner side of the left side of the reciprocating frame. The first rotating wheel is in contact with the cam. A reciprocating rod is fixedly mounted on the right side of the reciprocating frame. The circumferential side of the reciprocating rod is slidably connected to the inner side of the mounting frame. A vibration block is fixedly mounted at the right end of the reciprocating rod. A first spring is sleeved on the surface of the reciprocating rod inside the mounting frame. The lithium extraction vessel and the vessel cover are sealed together by bolts. The mounting frame has a guide groove inside that works with the reciprocating frame. When the cam rotates, the reciprocating frame, reciprocating rod and vibrating block move back and forth left and right through the cooperation of the first rotating wheel and the first spring, causing the vessel wall to vibrate slightly. A feeding mechanism is fixedly provided on the top of the inner wall of the vessel lid. The feeding mechanism includes a mounting shell fixedly provided on the top of the inner wall of the vessel lid. A rotating shaft is vertically rotatably connected inside the mounting shell. Pulleys are fixedly provided on the bottom end and the circumferential side of the rotating shaft. A belt is sleeved on the surface of the two pulleys. A rotating wheel is fixedly installed on the circumferential side of the rotating shaft and inside the mounting housing. Three mounting brackets are arranged in a circular array on the circumferential side of the rotating wheel. The bottom of each of the three mounting brackets is rotatably connected to a drive wheel by bolts. A feed hose is provided on the inner wall of the mounting housing. When the rotating wheel rotates, the drive wheel will contact the feed hose and squeeze the feed hose. The bottom of the mounting plate is fixedly equipped with a swing dosing mechanism. The swing dosing mechanism includes two rotating brackets fixedly mounted on the bottom of the mounting plate. The dosing pipe is rotatably connected inside the two rotating brackets. Multiple nozzles are connected to the surface of the dosing pipe. A swing gear is fixedly mounted on the circumferential side of the dosing pipe. A slider is slidably connected to the inner side of the mounting plate. A toothed assembly is provided at the bottom of the slider. The toothed assembly meshes with the swing gear. The slider is fixedly connected to the reciprocating frame by bolts. The bottom end of the feed hose is connected to the dosing pipe.

2. The apparatus for extracting battery-grade lithium carbonate from lepidolite according to claim 1, characterized in that, A seed crystal adding mechanism is fixedly installed on the left side of the top of the mounting plate. The seed crystal adding mechanism includes a sliding frame fixedly installed on the left side of the top of the mounting plate. A feeding plate is slidably connected to the inner side of the sliding frame. A second spring is provided on the left side of the feeding plate. A second rotating wheel is rotatably connected to the right side of the top of the feeding plate. The second rotating wheel is in contact with a cam. A material box is provided on the top of the lid. A discharge pipe is connected to the bottom of the material box.

3. The apparatus for extracting battery-grade lithium carbonate from lepidolite according to claim 2, characterized in that, The bottom of the discharge pipe is in contact with the top of the feeding plate, and the inner sides of both the feeding plate and the mounting plate are provided with feeding slots.

4. The apparatus for extracting battery-grade lithium carbonate from lepidolite according to claim 1, characterized in that, The lithium extraction vessel has an inlet pipe connected to its right side, a drain pipe connected to its bottom, and an exhaust pipe connected to the top of its lid. Four support seats are arranged in a circular array on the periphery of the lithium extraction vessel, and a support frame is provided at the bottom of the four support seats.

5. A process for extracting battery-grade lithium carbonate and co-producing calcium sulfate whiskers from lepidolite, characterized in that, The process includes the equipment for extracting battery-grade lithium carbonate as described in any one of claims 1-4 and the following steps: Step S1: Crush the lepidolite ore to a particle size of <2mm, and grind it to 60-80μm using a vibratory grinder to ensure that more than 90% of the particles pass through. Step S2: Mix lepidolite and calcium oxide in a certain ratio in a corundum crucible, then place it in a muffle furnace and heat it from room temperature to 1000-1400℃ at a certain heating rate for 30-40 minutes. Remove the crucible immediately after the thermal activation process is completed. Step S3: Quickly pour the activated slag into a pre-prepared iron bucket containing 10 liters of deionized water at room temperature for cooling. Simultaneously turn on the mechanical stirrer, control the stirring speed at 300 rpm, and continue stirring for 15 minutes to ensure that the slag is evenly dispersed and cooled to room temperature, thereby obtaining water-quenched slag. The slow-cooled slag in the furnace is obtained by thermally activating it and then cooling it at a certain rate. Step S4: After cooling, place the slag in an electric heating drying oven to dry, and grind it to 60-90 micrometers using a sealed experimental mill. The leaching process is carried out in a water bath. The finely ground slag at room temperature is mixed with the leaching agent at the specified temperature in a beaker at a certain liquid-solid ratio. The leaching solution and residue are obtained by magnetic stirring. The filter residue is washed twice with hot water, and the washing solution is added to the filtrate. Step S5: Slowly add calcium carbonate powder to the leachate, adjust the pH to 5.5, and stir to allow Fe³⁺ to form. + Al³ + Hydroxide precipitate is formed, and the precipitate is removed by filtration. The filtrate mainly contains Li. + 、Rb + Ca² + Mg² + Add sodium carbonate solution to the filtrate, with a molar concentration of 1 mol / L, to make Ca²⁺... + Mg² + The precipitate is carbonate. After filtration, ammonium oxalate solution is added dropwise to the clear liquid to test whether calcium and magnesium have been completely removed. The molar concentration is 0.1 mol / L. Li adsorption using ion exchange resin + 、Rb + Elute with 2 mol / L hydrochloric acid, collect the eluent, and concentrate by evaporation; Step S6: Heat the mixed solution obtained in step S5 to above 90°C. Under vigorous stirring, slowly add an excess of preheated saturated sodium carbonate solution. Lithium and rubidium in the solution will precipitate together to form a mixed solid of lithium carbonate and rubidium carbonate. At a high temperature above 90°C, vacuum filter is performed while hot. Most of the rubidium carbonate will dissolve in the hot water and be discharged with the filtrate, while lithium carbonate will be retained as a filter cake. The filter cake is thoroughly washed with hot deionized water above 80°C until the washing solution is tested with silver nitrate and no chloride ions are found. Step S7: Mix the leaching residue with deionized water at a certain liquid-solid ratio, add sulfuric acid to adjust the pH value to 5, stir for a certain time, and then add sodium dodecylbenzenesulfonate as a surfactant. Step S8: Transfer the slurry to a high-pressure reactor and react at 90-130℃ for 4 hours, maintaining a stirring rate of 200-400 rpm during the reaction. After the reaction is complete, allow it to cool naturally to room temperature and filter to collect the white whisker product.

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