Production method and device for preparing battery-grade lithium carbonate through continuous lithium deposition

Abstract

The invention provides a production method and device for preparing battery-grade lithium carbonate through continuous lithium deposition. The production method for preparing the battery-grade lithium carbonate through continuous lithium precipitation comprises the following steps that S1, a lithium-containing solution is prepared, brine prepared from lithium ore is subjected to purification and resin impurity removal to obtain the lithium-containing solution, and then the lithium-containing solution is put into a container and heated to 95 DEG C or above through water bath for standby application; s2, preparing a carbonate solution; S3, continuously precipitating lithium; s4, suction filtration and water washing. According to the production method for preparing the battery-grade lithium carbonate through continuous lithium deposition, a solution required by lithium deposition is pumped into the microtube jet high-shear mixer through an external peristaltic pump and other devices for reaction to generate lithium carbonate slurry, and then the particle size of the lithium carbonate is controlled through multiple shear layers in the microtube jet high-shear mixer; and the peritectic problem generally existing in lithium carbonate production is reduced, and the impurity content is reduced, so that the purpose of continuously depositing the battery-grade lithium carbonate is achieved.

Description

Technical Field

[0001] The present invention relates to the field of lithium carbonate preparation, and in particular to a production method and device for preparing battery-grade lithium carbonate by continuous lithium precipitation. Background Art

[0002] Lithium carbonate is a key raw material for the positive electrode of lithium-ion batteries, and its purity directly impacts battery performance. Currently, the industry primarily produces lithium carbonate using a batch precipitation process, which suffers from low production efficiency, high energy consumption, and unstable product quality.

[0003] Currently, there are several representative methods for preparing battery-grade lithium carbonate by continuous lithium precipitation:

[0004] First, regarding the prior art, Chinese invention patent CN107540005A discloses a continuous lithium precipitation device and its supporting production process. By introducing a continuous lithium precipitation device, this technical solution effectively breaks through the limitations of traditional intermittent production models and secondary lithium precipitation processes, achieving significant progress in improving production efficiency. Specifically, its process optimization achieved three key improvements: first, the original step-by-step operation was integrated into a continuous process, significantly reducing the number of process links; second, the unit time production capacity was significantly increased through equipment improvements; and third, it effectively saved equipment investment and raw material consumption costs. However, experimental verification showed that this solution still has design flaws in the material mixing process: the distance between the sodium carbonate solution inlet port and the concentrated lithium sulfate purification solution injection point is too large, and the staged addition method is used. The dual effects of spatial isolation and time difference make it difficult to achieve rapid and uniform mixing of the two reaction media. In actual operation, local agglomeration is prone to occur, resulting in a reduction in the solid-liquid contact area, which in turn causes problems such as incomplete chemical reaction, and ultimately leads to quality problems such as uneven product particle size distribution and irregular crystal morphology.

[0005] In another existing technology, Chinese patent CN110963512A proposes a method for continuous preparation of battery-grade lithium carbonate. This technical solution uses lithium chloride raw material liquid for multi-stage purification treatment, and specially introduces disodium ethylenediaminetetraacetic acid (EDTA-2Na) solution for deep removal of calcium ions, and then implements continuous synthesis with sodium carbonate auxiliary material in a multi-stage reaction system. Its innovations are mainly reflected in three aspects: ① Through the distributed feeding system combined with a two-way circulation mixing mechanism, the dynamic balance of the reaction system is achieved; ② The precise control of material flux technology is adopted to ensure stable control of the solid-liquid interface in the reactor; ③ A continuous production mode is constructed to increase the product yield to industrial-grade standards. Practical applications have shown that this process has technical advantages such as simple and efficient process flow and significantly reduced operating costs. In particular, it has shown good economic indicators during industrial scale-up, and the product purity rate can reach more than 98.5%. However, it should be noted that this technical solution has the problem of chelating agent residues during implementation. Although the added EDTA chelating agent can effectively improve the impurity removal efficiency, its subsequent treatment faces two technical bottlenecks: First, the post-processing process of the chelating agent residues is complicated and requires additional special separation equipment.

[0006] Therefore, it is necessary to provide a production method and device for preparing battery-grade lithium carbonate by continuous lithium precipitation to solve the above technical problems. Summary of the Invention

[0007] The present invention provides a production method and device for preparing battery-grade lithium carbonate by continuous lithium precipitation, which solves the problem that the current production process adopts a staged addition method, and the dual effects of spatial isolation and time difference make it difficult to achieve rapid and uniform mixing of two reaction media.

[0008] To solve the above technical problems, the present invention provides a production method for preparing battery-grade lithium carbonate by continuous lithium precipitation, comprising the following steps:

[0009] S1: Prepare a lithium-containing solution. The brine obtained from lithium ore is purified and impurities are removed by resin to obtain a lithium-containing solution. The lithium-containing solution is then placed in a container and heated to above 95°C in a water bath for standby use.

[0010] S2: Prepare a carbonate solution, prepare a carbonate solution of 320-360 g / L, then place the carbonate solution into a container and heat it in a water bath to above 95°C for later use;

[0011] S3: Continuous lithium precipitation: Turn on the microtube jet high shear mixer and set a certain working speed. Use a peristaltic pump to pump the lithium-containing solution and the carbonate solution into the microtube jet high shear mixer at a certain flow rate to mix and generate lithium carbonate and shear to control the particle size. After the lithium-containing solution pumping speed is set, the carbonate solution pumping speed is calculated according to the formula:

[0012] v(Na2CO3)=ρ(Li+)×v(Li+)×λ×106 / 13.88×ρ(Na2CO3);

[0013] Where v is the flow rate in mL / min, ρ is the mass concentration in g / L, and λ is the carbonate excess coefficient; the lithium carbonate slurry is collected in a beaker and placed in a water bath with stirring for at least 1 hour;

[0014] S4: Filter and wash with water. Filter the lithium carbonate slurry in S3 while it is hot to separate the solid and liquid. Then add the lithium carbonate solid into deionized water according to the preset solid-liquid ratio, wash with water and stir for 10 minutes, and then filter. Repeat the above water washing 2 to 5 times, taking a small amount of solid sample each time and placing it in a muffle furnace to dry for 2 hours at a drying temperature of 260°C.

[0015] Preferably, the lithium-containing solution includes one or more of post-resin brine or concentrated brine after resin and then three-stage preheating.

[0016] Preferably, the shear speed of the microtube jet high shear mixer is 900 to 1800 rpm.

[0017] Preferably, the brine flow rate is 5 to 100 mL / min, and the carbonate flow rate is 1 to 20 mL / min.

[0018] Preferably, the solid in S4 is added to deionized water above 95° C. at a solid-liquid ratio of 1:3.5 (mass ratio), washed with water and stirred for 10 minutes, and then filtered.

[0019] The present invention also provides a production device for preparing battery-grade lithium carbonate by continuous lithium precipitation, which is used in the production method for preparing battery-grade lithium carbonate by continuous lithium precipitation, comprising: a cleaning device, the cleaning device comprising a support platform, a stirring device, a filter cartridge, a cleaning cartridge, a lifting platform, a mounting arm, and a storage bucket;

[0020] The lifting platform is mounted on the support platform, the stirring device is mounted on the lifting platform, the lifting platform is used to lift the stirring device, the filter cartridge is mounted on the support platform, one end of the mounting arm is mounted on the lifting platform, one end of the cleaning cartridge is located inside the filter cartridge, the other end of the cleaning cartridge is detachably connected to the other end of the mounting arm, and the stirring blade of the stirring device is located inside the cleaning cartridge;

[0021] The cleaning cylinder comprises a cylinder body and a first filter element, wherein the first filter element is detachably mounted on the bottom of the cylinder body;

[0022] The bottom end of the filter cartridge is connected to the storage barrel through a valve and a liquid outlet pipe in sequence.

[0023] Preferably, the cleaning cylinder further comprises a second filter element, the second filter element is located between the first filter element and the cylinder body, and the filter pore diameter of the second filter element is larger than the particle size of lithium carbonate.

[0024] Preferably, the cleaning device also includes a connecting pin and a threaded pin, and a square sleeve and a threaded sleeve are embedded at intervals at the bottom of the cylinder body. The threaded pin passes through the first filter element and the second filter element in sequence and is threadedly connected to the threaded sleeve. The connecting pin passes through the square sleeve, and a top cap is provided at the top of the connecting pin. A square portion is provided on the connecting pin and below the top cap. The square portion is the same size as the inner cavity of the square sleeve. The first filter element and the second filter element are both sleeved on the connecting pin and located below the square sleeve, and the first filter element is fixedly connected to the connecting pin.

[0025] Preferably, the cleaning device further comprises a vibration structure, and when the cleaning cylinder is moved out of the filter cylinder, the vibration structure is used to drive the cleaning cylinder to vibrate back and forth, and the cleaning cylinder is slidably mounted on the mounting arm.

[0026] Preferably, the vibration structure includes a driving shaft and a cam, a cylindrical groove is provided at the bottom end of the stirring shaft in the stirring device, one end of the driving shaft is installed in the cylindrical groove, a driving tube is installed at the center of the second filter element, an elliptical cavity and a circular cavity are respectively provided at the top and bottom ends of the driving tube, and the elliptical cavity and the circular cavity are connected, and the other end of the driving shaft passes through the elliptical cavity and extends to the circular cavity and then connected to the cam.

[0027] Compared with related technologies, the production method and device for preparing battery-grade lithium carbonate by continuous lithium precipitation provided by the present invention have the following beneficial effects:

[0028] The present invention provides a production method and device for preparing battery-grade lithium carbonate by continuous lithium precipitation. The solution required for lithium precipitation is pumped into a microtube jet high-shear mixer by an external peristaltic pump or other device to react and produce lithium carbonate slurry. The lithium carbonate then passes through multiple shear layers inside the microtube jet high-shear mixer to control the particle size. The lithium carbonate then flows into a collector through a lower outlet for aging, thereby reducing the peritectic problem commonly existing in lithium carbonate production and lowering the impurity content, thereby achieving the purpose of continuously precipitating battery-grade lithium carbonate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A flowchart of the steps of the production method for preparing battery-grade lithium carbonate by continuous lithium precipitation provided by the present invention;

[0030] Figure 2 This is a schematic structural diagram of a cleaning device in a production device for preparing battery-grade lithium carbonate by continuous lithium precipitation provided by the present invention;

[0031] Figure 3for Figure 1 A schematic structural diagram of the cleaning device from another perspective is shown;

[0032] Figure 4 A schematic diagram of the structure inside the cleaning cylinder provided by the present invention;

[0033] Figure 5 A partial cross-sectional view of the cleaning device provided by the present invention;

[0034] Figure 6 for Figure 5 A magnified schematic diagram of point A in the middle;

[0035] Figure 7 This is a schematic diagram of the cleaning working state provided by the present invention, wherein: Figure 7 (a) is a schematic diagram of a stirring device stirring lithium carbonate solid particles in deionized water for cleaning. Figure 7 (b) is a schematic diagram showing the state in which the lifting platform lifts the cleaning cylinder by the mounting arm to separate the cleaned lithium carbonate solid particles from the deionized water;

[0036] Figure 8 A schematic diagram of a state where the first filter element and the second filter element provided by the present invention are staggered;

[0037] Figure 9 for Figure 8 A magnified schematic diagram of point B in the middle;

[0038] Figure 10 This is a structural schematic diagram of the cam provided by the present invention being located in an elliptical cavity.

[0039] Numbers in the figure:

[0040] 1. Support platform;

[0041] 2. Stirring device; 21. Motor; 22. Stirring shaft; 23. Stirring blade; 221. Cylindrical tank;

[0042] 3. Filter cartridge; 31. Support ring;

[0043] 4. Cleaning cylinder; 41. Cylinder body; 42. Second filter element; 43. First filter element; 44. Driving tube;

[0044] 411, threaded sleeve; 412, square sleeve; 413, mounting groove; 414, slider; 421, flange; 431, mounting frame; 432, filter membrane;

[0045] 441, elliptical cavity; 442, circular cavity;

[0046] 5. Lifting platform; 51. Lifting cylinder; 52. Assembly plate; 53. Telescopic arm;

[0047] 6. Mounting arm; 611. Spring; 612. Assembly slot;

[0048] 7. Vibration structure; 71. Drive shaft; 72. Cam;

[0049] 8. Threaded pin;

[0050] 9. Connecting pin; 91. Top cap; 92. Square portion;

[0051] 10. Storage barrel; 20. Liquid outlet pipe; 30. Valve. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0053] The present invention provides a production method for preparing battery-grade lithium carbonate by continuous lithium precipitation.

[0054] Please refer to Figure 1 In one embodiment of the present invention, the production method for preparing battery-grade lithium carbonate by continuous lithium precipitation comprises the following steps:

[0055] S1: Prepare a lithium-containing solution. The brine obtained from lithium ore is purified and impurities are removed by resin to obtain a lithium-containing solution. The lithium-containing solution is then placed in a container and heated to above 95°C in a water bath for standby use.

[0056] S2: Prepare a carbonate solution, prepare a carbonate solution of 320-360 g / L, then place the carbonate solution into a container and heat it in a water bath to above 95°C for later use;

[0057] S3: Continuous lithium precipitation: Turn on the microtube jet high shear mixer and set a certain working speed. Use a peristaltic pump to pump the lithium-containing solution and the carbonate solution into the microtube jet high shear mixer at a certain flow rate to mix and generate lithium carbonate and shear to control the particle size. After the lithium-containing solution pumping speed is set, the carbonate solution pumping speed is calculated according to the formula:

[0058] v(Na2CO3)=ρ(Li+)×v(Li+)×λ×106 / 13.88×ρ(Na2CO3);

[0059] Where v is the flow rate in mL / min, ρ is the mass concentration in g / L, and λ is the carbonate excess coefficient; the lithium carbonate slurry is collected in a beaker and placed in a water bath with stirring for at least 1 hour;

[0060] S4: Filter and wash with water. Filter the lithium carbonate slurry in S3 while it is hot to separate the solid and liquid. Then add the lithium carbonate solid into deionized water according to the preset solid-liquid ratio, wash with water and stir for 10 minutes, and then filter. Repeat the above water washing 2 to 5 times, taking a small amount of solid sample each time and placing it in a muffle furnace to dry for 2 hours at a drying temperature of 260°C.

[0061] The solution required for lithium precipitation is pumped into the microtube jet high shear mixer through an external peristaltic pump or other device to react and produce lithium carbonate slurry. The slurry then passes through the multi-layer shear layer inside the microtube jet high shear mixer to control the particle size of lithium carbonate, and then flows into the collector through the lower outlet for aging, thereby reducing the peritectic problem commonly existing in lithium carbonate production and lowering the impurity content, thereby achieving the purpose of continuous precipitation of battery-grade lithium carbonate.

[0062] As a preferred embodiment of the present invention, the lithium ore is one or more of spodumene, lepidolite, petalite, and apatite.

[0063] As a preferred embodiment of the present invention, the lithium-containing solution includes one or more of post-resin brine or post-resin concentrated brine that has been preheated three times.

[0064] As a preferred embodiment of the present invention, the brine concentration is 5-40 g / L; the carbonate concentration is 200-400 g / L; the brine is mainly composed of one or more of lithium chloride, lithium sulfate or lithium hydroxide, and the carbonate solution is mainly composed of one or more of sodium carbonate or potassium carbonate.

[0065] As a preferred embodiment of this invention, the carbonate excess coefficient is 0.5 to 1.5, and is set to 1.1 in this embodiment.

[0066] As a preferred embodiment of this embodiment, the shear speed of the microtube jet high shear mixer is 900 to 1800 rpm.

[0067] As a preferred embodiment of this invention, the brine flow rate is 5 to 100 mL / min, and the carbonate flow rate is 1 to 20 mL / min.

[0068] As a preferred embodiment of the present invention, the solid in S4 is added into deionized water at a solid-liquid ratio of 1:3.5 (mass ratio), washed with water and stirred for 10 minutes, and then filtered.

[0069] As an optional method of this embodiment, S1: preparation of lithium-containing solution, the brine prepared from lepidolite is purified, impurity-removed by resin and preheated in three stages to obtain concentrated brine, the main substance of which is lithium sulfate, wherein Li + The concentration is ≥18g / L. Pour it into a beaker and place it in a water bath and heat it to above 95℃ for later use.

[0070] At this time, the working speed of the microtube jet high shear mixer in S3 is 1200 rpm or 1500 rpm. When the working speed is 1200 rpm, the pumping speed of the lithium sulfate solution is 10 mL / min or 20 mL / min. When the working speed is 1500 rpm, the pumping speed of the lithium sulfate solution is 20 mL / min.

[0071] As another optional method of this embodiment, the lithium-containing solution is prepared by purifying the brine prepared from lepidolite and removing impurities from the resin to obtain a resin brine, the main substance of which is lithium sulfate; the resin brine is placed in a beaker and placed in a water bath and heated to above 95° C. for use;

[0072] In this embodiment, Li + Concentration ≥6g / L or Li + Concentration ≥20g / L or Li + Concentration ≥28 g / L;

[0073] The operating speed of the microtubule jet high shear mixer was 1500 rpm;

[0074] When Li + When the concentration is ≥6g / L, the corresponding lithium sulfate solution pumping speed is 50mL / min;

[0075] Li + Concentration ≥20g / L or Li + When the concentration is ≥28g / L, the corresponding lithium sulfate solution pumping speed is 20mL / min.

[0076] The present invention also provides a production device for preparing battery-grade lithium carbonate by continuous lithium precipitation.

[0077] See also Figure 2 and Figure 4 A production device for preparing battery-grade lithium carbonate by continuous lithium precipitation, used in the production method for preparing battery-grade lithium carbonate by continuous lithium precipitation, comprising: a cleaning device, the cleaning device comprising a support 1, a stirring device 2, a filter cartridge 3, a cleaning cartridge 4, a lifting platform 5, a mounting arm 6 and a storage bucket 10;

[0078] The lifting platform 5 is mounted on the support platform 1, the stirring device 2 is mounted on the lifting platform, and the lifting platform is used to lift the stirring device 2. The filter cartridge 3 is mounted on the support platform 1, and one end of the mounting arm 6 is mounted on the lifting platform 5. One end of the cleaning cartridge 4 is located inside the filter cartridge 3, and the other end of the cleaning cartridge 4 is detachably connected to the other end of the mounting arm 6. The stirring blade 23 of the stirring device 2 is located inside the cleaning cartridge 4.

[0079] The cleaning cylinder 4 includes a cylinder body 41 and a first filter element 43. The first filter element 43 is detachably mounted on the bottom of the cylinder body 41.

[0080] The bottom end of the filter cartridge 3 is connected to the storage barrel 10 through the valve 30 and the liquid outlet pipe 20 in sequence.

[0081] In this embodiment, the cleaning device is mainly used in step S4 to add the lithium carbonate solid to deionized water according to a preset solid-liquid ratio, wash and stir for 10 minutes, and then filter, and repeat the above washing 2 to 5 times; in this step, the water washing is mainly used to remove impurity ions attached to the lithium carbonate solid, such as sulfate ions, chloride ions, sodium ions, etc.

[0082] Due to the existing filtration equipment, after cleaning, the storage barrel is evacuated by a vacuum pump, and the liquid in the filter cartridge 3 is quickly discharged by negative pressure, and the solid is filtered out through the first filter element 43. When the cleaning liquid flows out, it will pass through the lithium carbonate solid again, so that the impurity ions in the liquid are easily attached to the lithium carbonate solid again, resulting in poor cleaning effect and requiring more cleaning times.

[0083] In this embodiment, the lithium carbonate solid to be cleaned is placed in the cleaning cylinder 4 and deionized water is added. At this time, the valve 30 is closed, and the stirring device 2 stirs and cleans the lithium carbonate solid for a preset time. Then the lifting platform 5 lifts the stirring device 2, and the mounting arm 6 drives the cleaning cylinder 4 to move upward at the same time. During the upward movement, the stirring device 2 continues to stir and clean. The cleaned deionized water passes through the first filter element 43 and is gradually separated from the lithium carbonate solid inside the cleaning cylinder 4. Figure 7 When the lithium carbonate solid is completely separated from the deionized water, the valve 30 is opened, and the deionized water enters the storage barrel 10 through the liquid outlet pipe 20. Subsequently, the lifting platform 5 descends, and the cleaning cylinder 4 enters the interior of the filter cartridge 3 again, and then deionized water is added, and the cleaning is repeated multiple times;

[0084] By first moving the lithium carbonate solid upward to separate it from the deionized water, and the stirring device 2 continuously stirring and cleaning during the movement, the ionized water is discharged after the lithium carbonate solid is completely separated from the deionized water. This can greatly reduce the impurities in the water from adhering to the lithium carbonate solid again due to the removal of the deionized water first, thereby affecting the cleaning efficiency.

[0085] See also Figure 1 In this embodiment, the storage barrel 10 is located below the cleaning barrel 4, and deionized water can automatically flow into the interior of the storage barrel 10 through the liquid outlet pipe 20;

[0086] Of course, a vacuum pump can also be set up, and the vacuum pump is connected to the storage barrel 10 through a pipe; the gas inside the storage barrel 10 is extracted to generate negative pressure, so that the deionized water in the filter cartridge 3 can quickly enter the storage barrel 10, or when the storage barrel 10 is placed at a height not lower than the filter cartridge 3, the vacuum pump is used to extract the gas inside the storage barrel 10, and the negative pressure is used to quickly discharge the deionized water into the storage barrel 10.

[0087] The bottom side of the storage barrel 10 is connected to a drain pipe, and a valve is provided on the drain pipe to facilitate the discharge of the collected deionized water.

[0088] A support ring 31 is provided inside the filter cartridge 3 for supporting the cleaning cartridge 4 .

[0089] See also Figure 3 In this embodiment, the lifting platform 5 includes a lifting cylinder 51, an assembly plate 52 and two telescopic arms 53. The lifting cylinder 51 is installed on the support platform 1, and the two telescopic arms 53 are installed on the support platform 1 and are located on both sides of the lifting cylinder 51. The assembly plate 52 is installed at the output end of the lifting cylinder 51 and the telescopic ends of the two telescopic arms 53.

[0090] The motor 21 in the stirring device 2 is mounted on the assembly plate 52 , and the number of the mounting arms 6 is preferably two, which are mounted on both sides of the assembly plate 52 .

[0091] The assembly plate 52 is driven to move up and down by the lifting cylinder 51 , thereby driving the assembly plate 52 and the installation arm 6 to move up and down.

[0092] Among them, the lifting cylinder 51 can be a pneumatic cylinder, a hydraulic cylinder, or an electric push rod, etc. The telescopic arm 53 includes a support arm and a guide rod. The support arm is installed on the support platform 1, one end of the guide rod is slidably installed in the support arm, and the other end of the guide rod is connected to the assembly plate 52.

[0093] The stirring device 2 includes a motor 21, a stirring shaft 22 and stirring blades 23. The stirring shaft 22 connects the output end of the motor 21 and the stirring blades 23. In this embodiment, the stirring blades 23 are provided in two groups, which are arranged on the stirring shaft 22 in an upper and lower manner. Each group of stirring blades 23 includes two stirring blades, which are symmetrically arranged.

[0094] See also Figure 4 and 5 As a preferred embodiment of this embodiment, the cleaning cylinder 4 further includes a second filter element 42, which is located between the first filter element 43 and the cylinder body 41, and the filter pore diameter of the second filter element 42 is larger than the particle size of lithium carbonate.

[0095] By setting the second filter element 42, raw material impurities such as large solid particles that have not reacted completely can be filtered out in the lithium carbonate solid particles. That is, the first filter element 43 removes impurity ions smaller than the lithium carbonate solid particles, and the second filter element 42 is used to filter out large particles of impurities, thereby further improving the purity of the lithium carbonate solid particles.

[0096] First, the large particle impurities of lithium carbonate solid particles are filtered. When filtering, the lifting platform 5 lifts the installation arm 6 to move the cleaning cylinder 4 out of the filter cylinder 3. Figure 8, stagger the first filter element 43 and the second filter element 42, that is, stagger them with the cleaning cylinder 4 and the bottom, add lithium carbonate solid particles into the cleaning cylinder 4, and the lithium carbonate solid particles pass through the second filter element 42 into the receiving container placed in advance below the cleaning cylinder 4. Subsequently, the cleaning cylinder 4 is disassembled, and the impurities filtered in the cleaning cylinder 4 are poured out. Subsequently, the lithium carbonate solid particles are added into the cleaning cylinder 4, and deionized water is added to clean the impurity ions as described above.

[0097] After subsequent cleaning, the first filter element 43 and the second filter element 42 are separated in the same manner, and the cleaned lithium carbonate solid is discharged from the cleaning cylinder 4 .

[0098] See also Figure 6 The first filter element 43 includes a mounting frame 431 and a filter membrane 432. A circular groove is provided on the top of the mounting frame 431, and the filter membrane 432 is provided in the circular groove. A plurality of holes are provided on the bottom of the mounting frame 431. Deionized water passes through the filter membrane 432 and is discharged through the plurality of holes.

[0099] The second filter element 42 is a filter plate having filter holes formed thereon. The diameter of the filter holes is larger than the lithium carbonate solid particles.

[0100] The second filter element 42 may also be configured in the same manner as the first filter element 43 .

[0101] The top of the mounting frame 431 fits against the bottom of the second filter element 42 , which can limit the filter membrane 432 in the vertical direction.

[0102] When the first filter element 43 is separated from the second filter element 42 , it is convenient to assemble or disassemble the filter membrane 432 .

[0103] See also Figure 6 As an optional manner of this embodiment, the cleaning device further includes a connecting pin 9 and a threaded pin 8. A square sleeve 412 and a threaded sleeve 411 are embedded at intervals at the bottom of the barrel 41. The threaded pin 8 sequentially passes through the first filter element 43 and the second filter element 42 and is threadedly connected to the threaded sleeve 411. The connecting pin 9 passes through the square sleeve 412. A top cap 91 is provided at the top of the connecting pin 9. A square portion 92 is provided on the connecting pin 9 and below the top cap 91. The square portion 92 has the same size as the inner cavity of the square sleeve 412. The first filter element 43 and the second filter element 42 are both sleeved on the connecting pin 9 and located below the square sleeve 412, and the first filter element 43 is fixedly connected to the connecting pin 9.

[0104] When it is necessary to stagger the first filter element 43 with the second filter element 42, the threaded pin 8 can be unscrewed, and then the connecting pin 9 can be rotated to drive the first filter element 43 to rotate so as to separate and stagger the first filter element 43 from the second filter element 42. Figure 8Then, the connecting pin 9 is moved downwards to be inserted into the square portion 92 and the square sleeve 412 to limit its axial position. Subsequently, the threaded pin 8 can be threadedly connected to the threaded sleeve 411 again to support the second filter element 42, thereby separating the first filter element 43 from the second filter element 42.

[0105] When the square portion 92 is inserted into the square sleeve 412 , the top cap 91 is located at the top of the square sleeve 412 . The top cap 91 is supported by the square sleeve 412 , thereby limiting the vertical position of the connecting pin 9 .

[0106] Among them, the number of threaded sleeves 411 and threaded pins 8 is preferably set to multiple, and in this embodiment, three are set correspondingly, which are arranged around the cleaning cylinder 4. By setting multiple threaded sleeves 411 and threaded pins 8, the first filter element 43 and the second filter element 42 are limited from multiple positions, thereby improving the stability of the limitation, and an installation groove 413 is provided at the bottom of the cylinder body 41 corresponding to the position of the threaded sleeve 411 and the square sleeve 412 for installing the threaded sleeve 411 and the square sleeve 412.

[0107] The first filter element 43 and the second filter element 42 are provided with assembly holes corresponding to the threaded pin 8 and the connecting pin 9 .

[0108] As another optional method of this embodiment, the connecting pin 9 can also be eliminated, and the connecting pin 9 and the square sleeve 412 can be replaced with the threaded pin 8 and the threaded sleeve 411 respectively. When separating the first filter element 43 and the second filter element 42, the threaded pin 8 is removed in turn, the first filter element 43 is removed, and then the threaded pin 8 is installed to support the second filter element 42.

[0109] See also Figure 5 and Figure 6 As an optional method of this embodiment, the cleaning device also includes a vibration structure 7. When the cleaning cylinder 4 is moved out of the filter cylinder 3, the vibration structure 7 is used to drive the cleaning cylinder 4 to vibrate back and forth. The cleaning cylinder 4 can be slidably mounted on the mounting arm 6.

[0110] By providing the vibration structure 7 , when filtering large impurities from lithium carbonate solids or discharging the materials after subsequent cleaning, the vibration structure 7 drives the cleaning cylinder 4 to vibrate back and forth, thereby allowing the lithium carbonate particles to be discharged quickly and evenly from the second filter element 42 .

[0111] See also Figure 4 and Figure 5As a preferred embodiment of the present invention, an assembly groove 612 is provided at one end of the mounting arm 6 away from the mounting plate 52, a spring 611 is installed in the assembly groove 612, sliders 414 are correspondingly installed on both sides of the cleaning cylinder 4, and pulleys are provided at the bottom of the sliders 414. When the cleaning cylinder 4 and the mounting arm 6 are mounted, the two sliders 414 are correspondingly placed in the two assembly grooves 612, the pulleys abut against the groove walls of the assembly groove 612, and the ends of the sliders 414 abut against the spring 611, thereby achieving a sliding connection between the cleaning cylinder 4 and the mounting arm 6;

[0112] During disassembly, the cleaning cylinder 4 is slightly lifted to move the slider 414 out of the assembly groove 612, and then the cleaning cylinder 4 is rotated to stagger the slider 414 and the mounting arm 6, and then the cleaning cylinder 4 is lowered to separate it from the stirring shaft 22. Of course, during disassembly, the lifting platform 5 first lifts the stirring device 2 to remove the filter cylinder 3.

[0113] When the cleaning cylinder 4 subsequently vibrates, the spring 611 acts as a buffer, improving the stability of the vibration of the cleaning cylinder 4. A guide post is provided within the assembly slot 612, and the spring 611 is sleeved on the guide post, guiding and limiting the extension and contraction of the spring 611. A gap is left between the guide post and the slider 414.

[0114] Please refer again Figure 5 and Figure 6 As an optional method of this embodiment, the vibration structure 7 includes a drive shaft 71 and a cam 72. The bottom end of the stirring shaft 22 in the stirring device 2 is provided with a cylindrical groove 221. One end of the drive shaft 71 is installed in the cylindrical groove 221. A driving tube 44 is installed in the center of the second filter element 42. The top and bottom ends of the driving tube 44 are respectively provided with an elliptical cavity 441 and a circular cavity 442, and the elliptical cavity 441 and the circular cavity 442 are connected. The other end of the drive shaft 71 passes through the elliptical cavity 441 and extends to the circular cavity 442 and then connects to the cam 72.

[0115] The long diameter of the circular cavity 442 is greater than or equal to the long diameter of the elliptical cavity 441 .

[0116] When the lithium carbonate solid is cleaning impurity ions, the cam 72 is located in the circular cavity 442. When the motor 21 drives the stirring shaft 22 to drive the stirring blade 23 to rotate, the stirring blade 23 drives the lithium carbonate to rotate in the deionized water for cleaning. The stirring shaft 22 drives the cam 72 to rotate through the drive shaft 71 without interacting with the driving tube 44, so that the driving tube 44 generates a horizontal force.

[0117] When filtering large impurities or discharging lithium carbonate solids subsequently, after the threaded pin 8 is unscrewed in sequence and the rotating connecting pin 9 drives the first filter element 43 to rotate 180 degrees to stagger with the second filter element 42, the connecting pin 9 moves the first filter element 43 downward so that the square portion 92 of the connecting pin 9 is inserted into the square sleeve 412. At this time, due to the downward movement of the first filter element 43, the second filter element 42 moves downward accordingly. The portion of the second filter element 42 sleeved on the connecting pin 9 is supported on the first filter element 43. The threaded pin 8 is subsequently reinstalled to support the second filter element 42. When the second filter element 42 moves downward, the driving tube 44 moves downward accordingly, so that the cam 72 enters the elliptical cavity 441 from the circular cavity 442. When the motor 21 drives the stirring shaft 22 to rotate, the driving shaft 71 drives the cam 72 to rotate, and acts on the narrow inner walls on both sides of the elliptical cavity 441, driving the entire cleaning cylinder 4 to vibrate back and forth through the second filter element 42, thereby realizing the function of vibration discharge. At this time, the stirring shaft 22 drives the stirring blade 23 to rotate, which can assist in the discharge of lithium carbonate solid particles.

[0118] Thus, the stirring device 2 can stir and clean the lithium carbonate solid in one state, and drive the vibration structure 7 to drive the cleaning cylinder 4 to vibrate back and forth in another state, thereby achieving rapid and uniform discharge, and realizing switching between the two states in the process of switching the first filter element 43 and the second filter element 42.

[0119] Among them, when the second filter element 42 is a filter plate, the driving tube 44 is installed on the center of the first filter element 43; when the second filter element 42 is set in the same way as the first filter element 43, the driving tube 44 is installed on the mounting frame 431 of the second filter element 42, and the corresponding filter membrane 432 has a center hole in the center and is sleeved on the driving tube 44.

[0120] Among them, see Figure 4 In this embodiment, a flange 421 is provided on the second filter element 42. The flange 421 is in contact with the inner wall of the cleaning cylinder 4. When the second filter element 42 moves downward, the flange 421 still partially contacts the inner wall of the cylinder body 41, thereby preventing a gap from forming between the second filter element 42 and the cylinder body 41, and preventing the solid lithium carbonate shell from flowing out through the gap.

[0121] When the cleaning cylinder 4 and the mounting arm 6 are installed, the stirring shaft 22 is sleeved on the driving tube 44 through the cylindrical groove 221 at the bottom, thereby preventing the deionized water from driving the lithium carbonate solid particles into the driving tube 44. The driving tubes 44 are spaced apart to allow for upward and downward sliding.

[0122] Preferably, a sealing ring can be provided at the top end of the driving tube 44 , and the outer wall of the sealing ring fits against the inner wall of the cylindrical groove 221 to ensure sealing.

[0123] Each time the stirring device 2 stops working, the stirring shaft 22 rotates an integer number of times, so that the cam 72 can be aligned with the long diameter of the elliptical cavity 441 , so that the cam 72 can be removed from the driving tube 44 .

[0124] Among them, the production device for preparing battery-grade lithium carbonate by continuous lithium precipitation includes, in addition to a cleaning device, a microtube jet high shear mixer, a peristaltic pump, a water bath heating device, a muffle furnace, etc.

[0125] The working principle of the production device for preparing battery-grade lithium carbonate by continuous lithium precipitation provided by the present invention is as follows:

[0126] To filter out large particles of lithium carbonate solid particles, first, the lifting platform 5 lifts the mounting arm 6 to move the cleaning cylinder 4 out of the filter cylinder 3. Figure 8 , stagger the first filter element 43 and the second filter element 42, that is, stagger the cleaning cylinder 4 and the bottom, add lithium carbonate solid particles into the cleaning cylinder 4, and the lithium carbonate solid particles pass through the second filter element 42 into the receiving container placed in advance below the cleaning cylinder 4. Subsequently, the cleaning cylinder 4 is disassembled, and the impurities filtered in the cleaning cylinder 4 are poured out;

[0127] The lithium carbonate solid to be cleaned is placed in the cleaning cylinder 4 and deionized water is added. At this time, the valve 30 is closed, and the stirring device 2 stirs and cleans the lithium carbonate solid for a preset time. Then the lifting platform 5 lifts the stirring device 2, and the mounting arm 6 drives the cleaning cylinder 4 to move upward at the same time. During the upward movement, the stirring device 2 continues to stir and clean. The cleaned deionized water passes through the first filter element 43 and is gradually separated from the lithium carbonate solid inside the cleaning cylinder 4. Figure 7 When the lithium carbonate solid is completely separated from the deionized water, the valve 30 is opened, and the deionized water enters the storage barrel 10 through the liquid outlet pipe 20. Subsequently, the lifting platform 5 descends, and the cleaning cylinder 4 enters the interior of the filter cartridge 3 again, and then deionized water is added, and the cleaning is repeated many times.

[0128] Specifically, when the lithium carbonate solid is cleaned of impurity ions, the cam 72 is located in the circular cavity 442, and the motor 21 drives the stirring shaft 22 to drive the stirring blade 23 to rotate. The stirring blade 23 drives the lithium carbonate to rotate in the deionized water for cleaning. The stirring shaft 22 drives the cam 72 to rotate through the drive shaft 71 without interacting with the driving tube 44, so that the driving tube 44 generates a horizontal force.

[0129] When filtering large impurities or discharging lithium carbonate solids subsequently, after the threaded pin 8 is unscrewed in sequence and the rotating connecting pin 9 drives the first filter element 43 to rotate 180 degrees to stagger with the second filter element 42, the connecting pin 9 moves the first filter element 43 downward so that the square portion 92 of the connecting pin 9 is inserted into the square sleeve 412. At this time, due to the downward movement of the first filter element 43, the second filter element 42 moves downward accordingly. The portion of the second filter element 42 sleeved on the connecting pin 9 is supported on the first filter element 43. The threaded pin 8 is subsequently reinstalled to support the second filter element 42. When the second filter element 42 moves downward, the driving tube 44 moves downward accordingly, so that the cam 72 enters the elliptical cavity 441 from the circular cavity 442. When the motor 21 drives the stirring shaft 22 to rotate, the driving shaft 71 drives the cam 72 to rotate, and acts on the narrow inner walls on both sides of the elliptical cavity 441, driving the entire cleaning cylinder 4 to vibrate back and forth through the second filter element 42, thereby realizing the function of vibration discharge. At this time, the stirring shaft 22 drives the stirring blade 23 to rotate, which can assist in the discharge of lithium carbonate solid particles.

[0130] Thus, the stirring device 2 can stir and clean the lithium carbonate solid in one state, and drive the vibration structure 7 to drive the cleaning cylinder 4 to vibrate back and forth in another state, thereby achieving rapid and uniform discharge, and realizing switching between the two states in the process of switching the first filter element 43 and the second filter element 42.

[0131] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing battery-grade lithium carbonate by continuous lithium precipitation, characterized in that: The following steps are involved: S1: Prepare a lithium-containing solution. The brine obtained from lithium ore is purified and impurities are removed by resin to obtain a lithium-containing solution. The lithium-containing solution is then placed in a container and heated to above 95°C in a water bath for standby use. S2: Prepare a carbonate solution, prepare a carbonate solution of 320-360 g / L, then place the carbonate solution into a container and heat it in a water bath to above 95°C for later use; S3: Continuous lithium precipitation: Turn on the microtube jet high shear mixer and set a certain working speed. Use a peristaltic pump to pump the lithium-containing solution and the carbonate solution into the microtube jet high shear mixer at a certain flow rate to mix and generate lithium carbonate and shear to control the particle size. After the lithium-containing solution pumping speed is set, the carbonate solution pumping speed is calculated according to the formula: ； Where v is the flow rate in mL / min, ρ is the mass concentration in g / L, and λ is the carbonate excess coefficient; the lithium carbonate slurry is collected in a beaker and placed in a water bath with stirring for at least 1 hour; S4: Filter and wash with water. Filter the lithium carbonate slurry in S3 while it is hot to separate the solid and liquid. Then add the lithium carbonate solid into deionized water according to the preset solid-liquid ratio, wash and stir for 10 minutes, and then filter. Repeat the above water washing 2 to 5 times. Take a small amount of solid sample each time and place it in a muffle furnace to dry for 2 hours at a drying temperature of 260°C.

2. The method for preparing battery-grade lithium carbonate by continuous lithium precipitation according to claim 1, wherein The lithium-containing solution includes one or more of post-resin brine or concentrated brine after resin and then three-stage preheating.

3. The production method for preparing battery-grade lithium carbonate by continuous lithium precipitation according to claim 1, characterized in that The shear speed of the microtubule jet high shear mixer is 900-1800 rpm.

4. The production method for preparing battery-grade lithium carbonate by continuous lithium precipitation according to claim 1, characterized in that The brine flow rate is 5-100 mL / min, and the carbonate flow rate is 1-20 mL / min.

5. The production method for preparing battery-grade lithium carbonate by continuous lithium precipitation according to claim 1, characterized in that The solid in S4 was added into deionized water at a solid-liquid ratio of 1:3.5 (mass ratio) at a temperature above 95° C., washed with water and stirred for 10 minutes, and then filtered.

6. A production device for preparing battery-grade lithium carbonate by continuous lithium precipitation, characterized in that: A method for producing battery-grade lithium carbonate by continuous lithium precipitation according to any one of claims 1 to 5, comprising: a cleaning device comprising a support, a stirring device, a filter cartridge, a cleaning cartridge, a lifting platform, a mounting arm, and a storage bucket; The lifting platform is mounted on the support platform, the stirring device is mounted on the lifting platform, the lifting platform is used to lift the stirring device, the filter cartridge is mounted on the support platform, one end of the mounting arm is mounted on the lifting platform, one end of the cleaning cartridge is located inside the filter cartridge, the other end of the cleaning cartridge is detachably connected to the other end of the mounting arm, and the stirring blade of the stirring device is located inside the cleaning cartridge; The cleaning cylinder comprises a cylinder body and a first filter element, wherein the first filter element is detachably mounted on the bottom of the cylinder body; The bottom end of the filter cartridge is connected to the storage barrel through a valve and a liquid outlet pipe in sequence.

7. The production device for preparing battery-grade lithium carbonate by continuous lithium precipitation according to claim 6, characterized in that: The cleaning cylinder further includes a second filter element, which is located between the first filter element and the cylinder body. The filter pore diameter of the second filter element is larger than the particle size of lithium carbonate.

8. The production device for preparing battery-grade lithium carbonate by continuous lithium precipitation according to claim 7, characterized in that: The cleaning device also includes a connecting pin and a threaded pin. A square sleeve and a threaded sleeve are embedded at intervals at the bottom of the barrel. The threaded pin passes through the first filter element and the second filter element in sequence and is threadedly connected to the threaded sleeve. The connecting pin passes through the square sleeve. A top cap is provided at the top of the connecting pin. A square portion is provided on the connecting pin and below the top cap. The square portion has the same size as the inner cavity of the square sleeve. The first filter element and the second filter element are both sleeved on the connecting pin and located below the square sleeve, and the first filter element is fixedly connected to the connecting pin.

9. The production device for preparing battery-grade lithium carbonate by continuous lithium precipitation according to claim 8, characterized in that: The cleaning device further comprises a vibration structure, and when the cleaning cylinder is moved out of the filter cylinder, the vibration structure is used to drive the cleaning cylinder to vibrate back and forth, and the cleaning cylinder is slidably mounted on the mounting arm.

10. The production device for preparing battery-grade lithium carbonate by continuous lithium precipitation according to claim 9, characterized in that: The vibration structure includes a drive shaft and a cam. A cylindrical groove is provided at the bottom end of the stirring shaft in the stirring device. One end of the drive shaft is installed in the cylindrical groove. A driving tube is installed at the center of the second filter element. An elliptical cavity and a circular cavity are respectively provided at the top and bottom ends of the driving tube, and the elliptical cavity and the circular cavity are connected. The other end of the drive shaft passes through the elliptical cavity and extends to the circular cavity and then connected to the cam.

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