A method and apparatus for lithium recovery from high sodium, low lithium solutions by freeze-out of sodium and targeted extraction of lithium

Abstract

This invention provides a method and apparatus for lithium recovery from a high-sodium, low-lithium solution via cryogenic sodium precipitation and targeted extraction. The method comprises the following steps: S1, weighing sodium sulfate and lithium sulfate samples, dissolving them in deionized water to prepare a high-sodium, low-lithium solution; S2, determining the lithium and sodium ion content of the high-sodium, low-lithium solution using ICP-MS and atomic absorption spectroscopy; S3, freezing the high-sodium, low-lithium solution prepared in step S1 in a circulating freezer to obtain a solid-liquid mixture. The method and apparatus provided by this invention achieve low lithium carryover during sodium precipitation from a high-sodium, low-lithium solution, further realizing high-efficiency lithium resource recovery. Compared with traditional processes, the lithium carryover rate during sodium precipitation can be reduced to 0.2%, reducing energy consumption and operational difficulty while improving lithium recovery rate, making it suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of lithium recovery, and more particularly to a method and apparatus for recovering lithium from high-sodium, low-lithium solutions by freezing sodium precipitation and targeted extraction. Background Technology

[0002] In the process of purifying and separating valuable elements in lithium-ion batteries, industrial production often uses precipitants (such as sodium carbonate) to gradually separate various precious metals, which easily produces high-sodium, low-lithium solutions with high sodium content and relatively low lithium content.

[0003] Traditional methods for recovering lithium from high-sodium, low-lithium solutions include: (1) Direct evaporation concentration: This method directly precipitates sodium salt by heating the water in the high-sodium, low-lithium solution. It has extremely high energy consumption and economic costs. In addition, 2% of lithium is carried in the process of precipitating sodium salt, which limits the lithium recovery rate. (2) Membrane separation: Membrane separation technology (such as reverse osmosis, nanofiltration, electrodialysis, forward osmosis, etc.) is often used for the preliminary treatment of high-salt wastewater. The advantage of this method is that the energy consumption is relatively low. However, under high salt concentration conditions, the membrane is easily fouled and clogged, and frequent replacement and cleaning are required, which increases the operating cost. (3) Multi-effect evaporation combined with crystallization: In existing technologies, the process of combining multi-effect evaporation and crystallization is used for the resource-based treatment of wastewater. Different salts are separated by stepwise evaporation and crystallization. Compared with single-effect evaporation, this method has lower energy consumption. However, it still faces problems such as a certain amount of lithium loss, high energy consumption, complex equipment, and high operation and maintenance costs.

[0004] Currently, the conventional treatment method for high-sodium, low-lithium solutions is to heat and concentrate the solution to further increase the sodium content while reducing its volume, followed by evaporation and crystallization to precipitate sodium. The remaining concentrate is then returned to leaching or lithium precipitation. However, this process results in lithium loss during sodium precipitation, is lengthy, and some sodium returns to the system, leading to continuous sodium ion enrichment and a high sodium content in the precipitated lithium carbonate.

[0005] Therefore, it is necessary to provide a method and apparatus for recovering lithium from high-sodium, low-lithium solutions by freezing sodium precipitation and targeted extraction to solve the above-mentioned technical problems. Summary of the Invention

[0006] This invention provides a method and apparatus for recovering lithium from high-sodium, low-lithium solutions by freezing sodium precipitation and targeted extraction, which solves the problems in the prior art.

[0007] To address the aforementioned technical problems, the present invention provides a lithium recovery method for cryogenic sodium precipitation and targeted extraction from a high-sodium, low-lithium solution, comprising the following steps:

[0008] S1. Weigh out sodium sulfate and lithium sulfate samples, dissolve them in deionized water, and prepare a high-sodium, low-lithium solution.

[0009] S2. The lithium ion and sodium ion contents of the high-sodium, low-lithium liquid were determined by ICP-MS and atomic absorption spectrometry.

[0010] S3. The high-sodium, low-lithium liquid prepared in step S1 is frozen and crystallized in a circulating freezing device to obtain a solid-liquid mixture.

[0011] S4. The solid-liquid mixture obtained in step S3 is filtered through a recovery device to obtain sodium sulfate crystals and lithium-containing filtrate;

[0012] S5. The lithium-containing filtrate obtained in step S4 is added to the recovery device and CO2 gas is introduced to raise the temperature and precipitate lithium, resulting in a solid-liquid mixture.

[0013] S6. The solid-liquid mixture obtained in step S5 is filtered again through a recovery device to obtain lithium sulfate crystals and low-lithium filtrate.

[0014] S7. Extract the low-lithium filtrate obtained in step S6 using an extractant.

[0015] This invention also provides a lithium recovery device for cryogenic sodium precipitation and targeted extraction from a high-sodium, low-lithium solution, applied in the aforementioned lithium recovery method for cryogenic sodium precipitation and targeted extraction from a high-sodium, low-lithium solution. The device includes a base, a housing fixedly connected to the top of the base, a reaction vessel fixedly connected to the top of the housing, a stirring rod rotatably connected to the reaction vessel, a connecting plate fixedly connected to the top of the reaction vessel, a first pushing member mounted on the top of the connecting plate, a sliding plate fixedly connected to the bottom of the first pushing member, the first pushing member driving the sliding plate to move linearly up and down, a connecting rod fixedly connected to the bottom of the sliding plate, the connecting rod being inserted into the stirring rod, and the top of the housing fixedly connected to the reaction vessel. A drive assembly is fixedly connected to the reaction vessel, which drives the stirring rod to rotate to achieve material stirring. A discharge chute is provided at the bottom of the reaction vessel. A sealing plate is slidably connected inside the outer shell, and the sealing plate is fixedly connected to the connecting rod. A sliding block is slidably connected inside the outer shell, and an inclined plate is fixedly connected to the left side of the sliding block. A filter plate is installed on the left side of the outer shell. A limit assembly is installed on the right side of the outer shell, which supports the sliding block. A cleaning assembly is installed on the limit assembly, which cleans the filter plate. A spring-loaded component is fixedly connected to the bottom of the outer shell, and a discharge port is opened at the bottom of the outer shell. A collection chute is installed on the left side of the outer shell.

[0016] Preferably, the limiting component includes an L-shaped plate, a moving plate, an auxiliary block, a support block, and a first elastic element. The L-shaped plate is fixedly connected to the right side of the outer shell, the moving plate is slidably connected to the L-shaped plate, the auxiliary block is fixedly connected to the moving plate, the support block is fixedly connected to the moving plate, and the first elastic element is disposed between the moving plate and the L-shaped plate.

[0017] Preferably, the cleaning assembly includes a connecting frame, a mounting plate, and a plurality of cleaning needles. The connecting frame is fixedly connected to the moving plate, and the mounting plate is fixedly connected to the connecting frame. The plurality of cleaning needles are linearly distributed on the mounting plate, and the positions of the plurality of cleaning needles are aligned with the positions of the filter holes of the filter plate. The diameter of the cleaning needles is smaller than the diameter of the filter holes of the filter plate.

[0018] Preferably, the drive assembly includes a dual-axis motor, a worm gear, and a worm. The dual-axis motor is fixed to the reaction vessel, the worm gear is fixed to the outer surface of the stirring rod, and the worm is fixed to one of the output shafts of the dual-axis motor. The worm meshes with the worm gear.

[0019] Preferably, a suction pump is installed on the front of the outer shell, and both the inlet and outlet of the suction pump are connected to delivery pipes. One delivery pipe is connected to a collection tank, and the other delivery pipe is connected to the reaction vessel.

[0020] Preferably, a support frame is fixedly connected to the right side of the outer casing, a placement frame is fixedly connected to the top of the support frame, a lifting plate is slidably connected to the placement frame, two bearing plates are installed on the placement frame, a conical disc is supported on the two bearing plates, a second pushing member is installed on the support frame, a moving rod is fixedly connected to the second pushing member, the moving rod passes through the placement frame and the conical disc in sequence and is fixedly connected to the lifting plate, a support plate is fixedly connected to the moving rod, multiple gas cylinders are placed on the conical disc, an air intake assembly is installed on the reaction tank, and a transmission assembly is installed on the placement frame.

[0021] Preferably, the air intake assembly includes an air intake pipe, a sleeve, and a connector. One end of the air intake pipe is connected to the reaction vessel, the sleeve is slidably connected to the other end of the air intake pipe, and the sleeve is fixedly connected to the lifting plate. The connector is fixedly connected to the sleeve and inserted into the gas tank.

[0022] Preferably, the transmission assembly includes a fixed plate, a first transmission shaft, a second transmission shaft, two transmission wheels, a transmission belt, and a bevel gear. The fixed plate is fixedly connected to the placement frame, the first transmission shaft is rotatably connected to the fixed plate, the second transmission shaft is mounted on the drive assembly, the two transmission wheels are respectively fixed to the first transmission shaft and the second transmission shaft, the transmission belt is disposed on the outer surface of the two transmission wheels, and the bevel gear is fixedly connected to the first transmission shaft.

[0023] Preferably, the gas cylinder includes a cylinder body, a cylinder opening, a sealing piston, a second elastic element, and a gas outlet. The cylinder opening is located at the top of the cylinder body, the sealing piston is slidably connected inside the cylinder opening, the second elastic element is located at the bottom of the sealing piston, and the gas outlet is located on the cylinder opening.

[0024] Compared with related technologies, the lithium recovery method and apparatus for cryogenic sodium precipitation and targeted extraction from high-sodium, low-lithium solutions provided by this invention have the following advantages:

[0025] This invention provides a method and apparatus for lithium recovery from high-sodium, low-lithium solutions by freezing sodium precipitation and targeted extraction. This invention achieves low lithium carryover during sodium precipitation in high-sodium, low-lithium solutions, further realizing high-efficiency recovery of lithium resources. Compared with traditional processes, the lithium carryover rate during sodium precipitation can be reduced to 0.2%, reducing energy consumption and operational difficulty while improving lithium recovery rate, making it suitable for industrial production. Attached Figure Description

[0026] Figure 1 A schematic diagram illustrating lithium carrying capacity at different temperatures provided by this invention;

[0027] Figure 2 A schematic diagram illustrating the lithium carrying capacity at different stirring rates provided by this invention;

[0028] Figure 3 This is a schematic diagram of XRD patterns of the product at different temperatures provided by the present invention;

[0029] Figure 4 This is a schematic diagram of XRD patterns of the products under different crystallization times according to the present invention;

[0030] Figure 5 This is a schematic diagram of a second embodiment of the lithium recovery method and apparatus for freezing sodium precipitation and targeted extraction from a high-sodium, low-lithium solution provided by the present invention.

[0031] Figure 6 for Figure 5 A schematic diagram of the back of the reaction vessel shown;

[0032] Figure 7 for Figure 5 A top view of the reaction vessel shown;

[0033] Figure 8 for Figure 5 A cross-sectional schematic diagram of the outer casing is shown;

[0034] Figure 9 for Figure 8 The enlarged schematic diagram of part A shown below;

[0035] Figure 10An initial state diagram of the lithium recovery device for freezing sodium precipitation and targeted extraction from a high-sodium, low-lithium solution provided by the present invention;

[0036] Figure 11 This is a motion diagram of the lithium recovery device for cryogenic sodium precipitation and targeted extraction from a high-sodium, low-lithium solution provided by the present invention, wherein... Figure 11 (a) is a schematic diagram of solid-liquid separation. Figure 11 (b) is a schematic diagram of the filter plate cleaning process. Figure 11 (c) is a schematic diagram of the solid discharge state;

[0037] Figure 12 for Figure 6 The diagram shows the structure of the transmission assembly.

[0038] Figure 13 for Figure 5 The diagram shows the structure of the placement rack.

[0039] Figure 14 for Figure 13 A bottom view of the conical disk shown;

[0040] Figure 15 This is a diagram showing the extended state of the second pusher, where, Figure 15 (a) is a schematic diagram of the second pusher in its first extended state. Figure 15 (b) is a schematic diagram showing the state of the second pusher during its second extension. Figure 15 (c) is a schematic diagram of the third extension of the second pusher;

[0041] Figure 16 for Figure 13 The diagram shows the structure of the gas tank.

[0042] Numbering on the map:

[0043] 1. Base, 2. Outer shell, 3. Reaction vessel, 4. Stirring rod, 5. Connecting plate, 6. First pusher, 7. Sliding plate, 8. Connecting rod;

[0044] 9. Drive assembly; 91. Dual-axis motor; 92. Worm gear; 93. Worm.

[0045] 10. Discharge chute; 11. Sealing plate; 12. Sliding block; 13. Inclined plate; 14. Filter plate;

[0046] 15. Limiting component; 151. L-shaped plate; 152. Motion plate; 153. Auxiliary block; 154. Support block; 155. First elastic element;

[0047] 16. Cleaning components; 161. Connector bracket; 162. Mounting plate; 163. Cleaning pin;

[0048] 17. Springback component; 18. Discharge port; 19. Collection trough; 20. Suction pump; 21. Conveying pipe; 22. Support frame; 23. Placement rack; 24. Lifting plate; 25. Bearing plate; 26. Conical disc; 27. Second pusher; 28. Moving rod; 29. ​​Pallet.

[0049] 30. Gas cylinder; 301. Cylinder body; 302. Cylinder opening; 303. Sealing piston; 304. Second elastic element; 305. Gas outlet.

[0050] 31. Intake assembly; 311. Intake pipe; 312. Sleeve; 313. Connector;

[0051] 32. Transmission assembly; 321. Fixing plate; 322. First transmission shaft; 323. Second transmission shaft; 324. Transmission wheel; 325. Transmission belt; 326. Bevel gear. Detailed Implementation

[0052] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0053] First Embodiment

[0054] This invention provides a method for lithium recovery from a high-sodium, low-lithium solution by cryogenic precipitation and targeted extraction, comprising the following steps:

[0055] S1. Weigh 24.8g of sodium sulfate and 16.5g of lithium sulfate sample, dissolve them in 100mL of deionized water to prepare a high-sodium, low-lithium solution.

[0056] S2. The lithium and sodium ion contents of the high-sodium, low-lithium liquid were determined by ICP-MS and atomic absorption spectrometry, and the concentrations of lithium and sodium were found to be 64.5 g / L.

[0057] S3. Place the high-sodium, low-lithium solution prepared in step S1 in a refrigeration circulation device or recovery device at a temperature of 40°C, and carry out freeze crystallization under the conditions of stirring rate of 200 r / min, cooling rate of 1.6°C / min, minimum freezing temperature of 10°C, adding 0.5 g of sodium sulfate seed crystals, and crystallization time of 1 h to precipitate sodium sulfate.

[0058] S4. The solid-liquid mixture obtained in step S3 is filtered through a recovery device to obtain sodium sulfate crystals and lithium-containing filtrate. The filter residue is dried and then dissolved. The lithium content of the precipitated sodium sulfate crystals is measured by ICP-MS to be 0.14%.

[0059] S5. The lithium-containing filtrate obtained in step S4 is added to the recovery device and CO2 gas is introduced to raise the temperature and precipitate lithium, resulting in a solid-liquid mixture.

[0060] S6. The solid-liquid mixture obtained in step S5 is filtered again through a recovery device to obtain lithium sulfate crystals and low-lithium filtrate. The lithium and sodium concentrations of the low-lithium filtrate were measured by ICP-MS to be 2.7 g / L and 56.3 g / L, respectively.

[0061] S7. The low-lithium filtrate obtained in step S6 was extracted using an extractant. 100 mL of lithium extractant was prepared using a β-diketone to TBP ratio of 1:2 and kerosene as the diluent. 50 mL of the low-lithium filtrate was taken and extracted under the conditions of a 2:1 ratio, an extraction time of 5 min, and an extraction stirring rate of 250 r / min. Back-extraction was performed using 2 mol / L sulfuric acid. The lithium concentrations in the back-extraction solution and raffinate were measured by ICP-MS to be 2.63 g / L and 0.014 g / L, respectively. The lithium recovery rate was calculated to be 95.78%.

[0062] In this embodiment, the temperature in step S4 is 90°C; the lithium deposition time in step S4 is 6 hours.

[0063] Compared with related technologies, the lithium recovery method and apparatus for cryogenic sodium precipitation and targeted extraction from high-sodium, low-lithium solutions provided by this invention have the following advantages:

[0064] This invention achieves sodium precipitation and low lithium carryover in high-sodium, low-lithium solutions, further realizing high-efficiency lithium resource recovery. Compared with traditional processes, the lithium carryover rate during sodium precipitation can be reduced to 0.2%, reducing energy consumption and operational difficulty while improving lithium recovery rate, making it suitable for industrial production.

[0065] Second Embodiment

[0066] Please refer to the following: Figures 5-11The present invention also provides a lithium recovery device for cryogenic sodium precipitation and targeted extraction from a high-sodium, low-lithium solution, applied to the aforementioned lithium recovery method for cryogenic sodium precipitation and targeted extraction from a high-sodium, low-lithium solution. The device includes a base 1, a housing 2 fixedly connected to the top of the base 1, a reaction vessel 3 fixedly connected to the top of the housing 2, a stirring rod 4 rotatably connected to the reaction vessel 3, a connecting plate 5 fixedly connected to the top of the reaction vessel 3, a first pushing member 6 mounted on the top of the connecting plate 5, a sliding plate 7 fixedly connected to the bottom of the first pushing member 6, the first pushing member 6 driving the sliding plate 7 to move linearly up and down, a connecting rod 8 fixedly connected to the bottom of the sliding plate 7, the connecting rod 8 being inserted into the stirring rod 4, and a driving assembly 9 fixedly connected to the top of the housing 2. The moving component 9 is used to drive the stirring rod 4 to rotate to achieve material stirring. The bottom of the reaction tank 3 is provided with a discharge chute 10. The inside of the outer shell 2 is slidably connected with a sealing plate 11, which is fixedly connected to the connecting rod 8. The inside of the outer shell 2 is slidably connected with a sliding block 12. The left side of the sliding block 12 is fixedly connected with an inclined plate 13. The left side of the outer shell 2 is equipped with a filter plate 14. The right side of the outer shell 2 is equipped with a limiting component 15, which is used to support the sliding block 12. A cleaning component 16 is installed on the limiting component 15, which is used to clean the filter plate 14. The bottom of the outer shell 2 is fixedly connected with a spring-loaded component 17. The bottom of the outer shell 2 is provided with a discharge port 18. The left side of the outer shell 2 is equipped with a collection chute 19.

[0067] In this embodiment, the cleaning component 16 is located on the left side of the filter plate 14. Since the solution is filtered from the right side to the left side of the filter plate 14 during filtration, when the filter residue is too large and clogs the filter plate 14, forward cleaning will cause the filter plate 14 to be scrapped and the cleaning force is large. The cleaning component 16 cleans the filter plate 14 from left to right, which is easier and will not damage the filter plate 14.

[0068] In this embodiment, the first pushing member 6 includes, but is not limited to, a cylinder, a hydraulic cylinder, an electric push rod, and a linear motor, etc., as long as it can drive the sliding plate 7 to move up and down.

[0069] The top of the reaction vessel 3 is also equipped with a feed trough for material entry. The inner wall is embedded with heating wires and cooling coils. The heating wires are connected to an external power source using existing technology. The cooling coils contain a cooling medium and are connected to a refrigeration device using existing technology, which enables the heating and cooling of the reaction vessel 3.

[0070] Please refer to the following: Figure 8The sealing plate 11 is located at the bottom of the discharge trough 10 and abuts against the discharge trough 10 to seal the discharge trough 10. The sealing plate 11 is provided with a sealing gasket to improve the sealing performance. By extending the first pusher 6, the connecting rod 8 can be moved down indirectly, thereby controlling the movement of the sealing plate 11 to meet the requirements of controlling the opening and closing of the discharge trough 10.

[0071] The spring-loaded component 17 includes, but is not limited to, a pneumatic telescopic rod, a spring, an elastic strip, etc. It only needs to store energy after the inclined plate 13 moves downward, so that the inclined plate 13 can spring back to its original position when the inclined plate 13 is no longer subjected to downward force.

[0072] Please refer to the following: Figure 10 In the initial state, the discharge chute 10 is blocked by the sealing plate 11, so the inside of the reaction tank 3 is a closed environment. After opening the upper feed chute and sending the material into the reaction tank 3, the material can react inside the reaction tank 3, and the stirring rod 4 can be driven to rotate by the drive component 9 to increase the reaction rate.

[0073] Please refer to the following: Figure 11 (a) When the first pusher 6 extends for the first time, the entire device is in the discharge state. The first pusher 6 will drive the sliding plate 7 to move downward, thereby driving the connecting rod 8 to move downward, which in turn causes the sealing plate 11 to move downward, no longer blocking the discharge chute 10, so that the discharge chute 10 opens to discharge material, and the material is filtered through the filter plate 14.

[0074] Please refer to the following: Figure 9 The limiting component 15 includes an L-shaped plate 151, a moving plate 152, an auxiliary block 153, a support block 154, and a first elastic element 155. The L-shaped plate 151 is fixedly connected to the right side of the outer shell 2. The moving plate 152 is slidably connected to the L-shaped plate 151. The auxiliary block 153 is fixedly connected to the moving plate 152. The support block 154 is fixedly connected to the moving plate 152. The first elastic element 155 is disposed between the moving plate 152 and the L-shaped plate 151.

[0075] In this embodiment, the first elastic element 155 includes, but is not limited to, a spring, a sheet, or a pneumatic piston rod, and only needs to satisfy the requirement of applying a leftward elastic force to the moving plate 152.

[0076] Please refer to the following: Figure 8 In this embodiment, the top of the auxiliary block 153 is provided with a slope, which makes it easier for the sealing plate 11 to press down and apply pressure to the auxiliary block 153 through the slope, thereby realizing the rightward movement of the auxiliary block 153;

[0077] Preferably, the distance between the auxiliary block 153 and the support block 154 is exactly equal to the height of the sliding block 12, so that the auxiliary block 153 abuts against the top of the sliding block 12 and the support block 154 abuts against the bottom of the sliding block 12, thereby restricting the sliding block 12 and fixing the inclined plate 13.

[0078] By supporting the sliding block 12 with the support block 154, the inclined plate 13 can be supported, thereby preventing the inclined plate 13 from moving downward due to gravity after the material falls onto it.

[0079] Please refer to the following: Figure 11 (b) When the first pusher 6 extends for the second time, it will cause the sealing plate 11 to move downward. When the sealing plate 11 touches the inclined surface at the top of the auxiliary block 153, it will apply pressure to the right to the auxiliary block 153, thereby causing the auxiliary block 153 to move to the right, and then causing the moving plate 152 to move to the right to squeeze the first elastic member 155. The movement of the moving plate 152 to the right can cause the support block 154 to move to the right, so that it no longer supports the sliding block 12, so that the sliding block 12 has space to move downward.

[0080] Please refer to the following: Figure 11 (c) When the first pusher 6 extends for the third time, it will cause the sealing plate 11 to continue to move downward, which will abut against the sliding block 12 and cause the sliding block 12 to move downward, thereby causing the inclined plate 13 to move downward and squeeze the spring member 17. After the inclined plate 13 moves downward, an open opening appears, allowing the filter residue to be discharged from the discharge port 18.

[0081] When the first pusher 6 retracts and resets, the springback member 17 will cause the inclined plate 13 to spring back, and the sealing plate 11 will move upward and no longer apply pressure to the auxiliary block 153. At this time, the first elastic member 155 will also cause the moving plate 152 to reset, so that the support block 154 will support the inclined plate 13 again.

[0082] Preferably, when the first pusher 6 moves to its maximum stroke, the sliding block 12 always abuts against the left side of the support block 154 to prevent the support block 154 from blocking the sliding plate 12 after it resets.

[0083] Please refer to the following: Figures 5-6 The cleaning assembly 16 includes a connecting frame 161, a mounting plate 162, and a plurality of cleaning needles 163. The connecting frame 161 is fixedly connected to the moving plate 152, and the mounting plate 162 is fixedly connected to the connecting frame 161. The plurality of cleaning needles 163 are linearly distributed on the mounting plate 162, and the positions of the plurality of cleaning needles 163 are aligned with the positions of the filter holes of the filter plate 14, and the diameter of the cleaning needles 163 is smaller than the diameter of the filter holes of the filter plate 14.

[0084] Please refer to it again. Figure 11(b) When the first pusher 6 extends for the second time, it causes the sealing plate 11 to move downward. The sealing plate 11 causes the auxiliary block 153 to move to the right, which in turn causes the moving plate 152 to move to the right and squeeze the first elastic member 155. The movement of the moving plate 152 to the right will cause the connecting frame 161 to move to the right, thereby causing the mounting plate 162 to move to the right, so that the cleaning needle 163 cleans the filter holes of the filter plate 14.

[0085] It should be noted that the cleaning component 16 cleans from left to right, while the filter plate 14 filters from right to left during operation. Therefore, the clogging direction of the filter plate 14 is also from right to left. By cleaning in reverse by the cleaning component 16, it is possible to prevent filter residue from forming a dead end inside the filter plate 14 (the filter residue cannot be discharged through the forward water flow) and cleaning is easier.

[0086] Please refer to the following: Figure 7 The drive assembly 9 includes a dual-axis motor 91, a worm gear 92, and a worm 93. The dual-axis motor 91 is fixed to the reaction tank 3, the worm gear 92 is fixed to the outer surface of the stirring rod 4, and the worm 93 is fixed to one of the output shafts of the dual-axis motor 91. The worm 93 meshes with the worm gear 92.

[0087] In use, the rotation of the dual-shaft motor 91 drives the worm gear 93 to rotate, which in turn enables the worm wheel 92 to rotate, thereby driving the stirring rod 4.

[0088] It is understood that in other embodiments, the worm gear 92 and the worm 93 can be in the form of a helical gear set and other transmission components, as long as the dual-shaft motor 91 drives the stirring rod 4.

[0089] Please refer to it again. Figure 7 A suction pump 20 is installed on the front of the outer shell 2. The inlet and outlet of the suction pump 20 are both connected to a delivery pipe 21. One delivery pipe 21 is connected to the collection tank 19, and the other delivery pipe 21 is connected to the reaction tank 3.

[0090] The liquid inside the collection tank 19 can be sent back into the reaction tank 3 through the delivery pipe 21 by the suction pump 20 for further processing, which improves the convenience of use.

[0091] It is understood that in other embodiments, the suction pump 20 may be replaced by other liquid delivery devices.

[0092] Please refer to the following: Figures 13-16A support frame 22 is fixedly connected to the right side of the outer shell 2. A placement frame 23 is fixedly connected to the top of the support frame 22. A lifting plate 24 is slidably connected to the placement frame 23. Two bearing plates 25 are installed on the placement frame 23. A conical disc 26 is supported on the two bearing plates 25. A second pushing member 27 is installed on the support frame 22. A moving rod 28 is fixedly connected to the second pushing member 27. The moving rod 28 passes through the placement frame 23 and the conical disc 26 in sequence and is fixedly connected to the lifting plate 24. A support plate 29 is fixedly connected to the moving rod 28. Multiple gas cylinders 30 are placed on the conical disc 26. An air intake assembly 31 is installed on the reaction tank. A transmission assembly 32 is installed on the placement frame 23.

[0093] Please refer to the following: Figure 15 (a) The gas tank 30 is filled with CO2. Through the cooperation of the gas tank 30 and the gas inlet assembly 31, CO2 can be introduced into the reaction tank 3.

[0094] Please refer to the following: Figure 15 (b) By extending the second pusher 27, the tray 29 can be moved upward to abut against the bottom of the conical disc 26, and the lifting plate 24 can also be moved upward, thereby moving the sleeve 312 upward, so that the connector 313 is separated from the gas tank 30.

[0095] Please refer to the following: Figure 15 (c) By extending the second pusher 27 again, the tray 29 can be driven to continue moving upward, thereby driving the conical disk 26 to move upward and contact the transmission component 32. By cooperating with the drive component 9, the transmission component 32 is rotated, thereby driving the conical disk 26 to rotate by a preset angle, thereby enabling the current gas tank 30 to be moved away and the next gas tank 30 to move to the bottom of the connector 313.

[0096] Finally, the second pusher 27 is reset, causing the connector 313 to move down and be inserted into the new gas cylinder 30, which facilitates the replacement of the gas cylinder 30 after use.

[0097] Preferably, a snap-fit ​​structure can be provided between the bottom of the gas tank 30 and the conical disc 26 to achieve convenient fixation;

[0098] In one embodiment, a positioning structure is provided between the support plate 25 and the conical disk 26. The positioning structure includes a positioning block and a positioning groove. The positioning block is fixed to the top of the support plate 25, and the positioning groove is opened at the bottom of the conical disk 26. By inserting the positioning block into the positioning groove, the stability of the conical disk 26 can be improved.

[0099] It should be noted that there are multiple positioning slots, the number of which matches the number of gas tanks 30, and they are distributed in a ring at equal intervals at the bottom of the conical disc 26.

[0100] Please refer to it again. Figure 13 The air intake assembly 31 includes an air intake pipe 311, a sleeve 312, and a connector 313. One end of the air intake pipe 311 is connected through to the reaction vessel 3. The sleeve 312 is slidably connected to the other end of the air intake pipe 311 and is fixedly connected to the lifting plate 24. The connector 313 is fixedly connected to the sleeve 312 and is inserted into the gas tank 30.

[0101] Preferably, the air inlet pipe 311 is also equipped with a one-way valve, and the air inlet pipe 311 extends to the bottom of the inner wall of the reaction vessel 3.

[0102] Please refer to the following: Figure 12 The transmission assembly 32 includes a fixed plate 321, a first transmission shaft 322, a second transmission shaft 323, two transmission wheels 324, a transmission belt 325, and a bevel gear 326. The fixed plate 321 is fixedly connected to the placement frame 23. The first transmission shaft 322 is rotatably connected to the fixed plate 321. The second transmission shaft 323 is mounted on the drive assembly 9. The two transmission wheels 324 are respectively fixed to the first transmission shaft 322 and the second transmission shaft 323. The transmission belt 325 is disposed on the outer surface of the two transmission wheels 324. The bevel gear 326 is fixedly connected to the first transmission shaft 322.

[0103] In this embodiment, the transmission wheel 324 and the transmission belt 325 can be in the form of a belt and pulley, a chain and sprocket, or a gear set, as long as they satisfy the transmission between the second transmission shaft 323 and the first transmission shaft 322.

[0104] In use, when the drive assembly 9 rotates, it can drive the second drive shaft 323 to rotate, thereby cooperating with the drive wheel and drive belt 325 to make the first drive shaft 322 rotate, which in turn can drive the bevel gear 326 to rotate. When the conical disc 26 contacts the bevel gear 326, the rotation of the conical disc 26 can be controlled.

[0105] Please refer to the following: Figure 16 The gas tank 30 includes a tank body 301, a tank opening 302, a sealing piston 303, a second elastic element 304, and a gas outlet 305. The tank opening 302 is located at the top of the tank body 301. The sealing piston 303 is slidably connected inside the tank opening 302. The second elastic element 304 is located at the bottom of the sealing piston 303. The gas outlet 305 is opened on the tank opening 302.

[0106] Preferably, the gas tank 30 is also equipped with a safety valve.

[0107] In this embodiment, the second elastic element 304 includes, but is not limited to, a spring, a sheet, or a pneumatic piston rod, as long as it can apply an upward elastic force to the sealing piston 303.

[0108] When the air intake assembly 31 is combined with the gas tank 30, the plug 313 is first inserted from the tank opening 302, and then the sealing piston 303 will be pressed downward to squeeze the second elastic element 304. After the sealing piston 303 moves down, the outlet 305 will be gradually exposed, so that it can communicate with the plug 313. The gas inside the gas tank 30 will enter the reaction vessel 3 through the air intake assembly 31.

[0109] When the connector 313 is pulled out, the sealing piston 303 will be reset by the rebound of the second elastic element 304, blocking the air outlet 305 and ensuring the air tank 30 is sealed.

[0110] The working principle of the lithium recovery method and apparatus for cryogenic sodium precipitation and targeted extraction from high-sodium, low-lithium solutions provided by this invention is as follows:

[0111] When the material enters the reaction tank 3, the drive component 9 drives the stirring rod 4 to rotate, which can stir and react the material. Then, the extension of the first pusher 6 drives the sliding plate 7 to move downward, thereby causing the connecting rod 8 to move downward, which in turn drives the sealing plate 11 to move downward and no longer seals the discharge chute 10. The material will be discharged from the discharge chute 10 and undergo solid-liquid separation through the filter plate 14. The filtrate passes through the filter plate 14 and enters the collection tank 19, while the filter residue remains on the top of the inclined plate 13.

[0112] The extension of the first pusher 6 will cause the sliding plate 7 to continue to move downward, thereby indirectly causing the sealing plate 11 to continue to move downward, which will squeeze the limiting component 15 and cause the limiting component 15 to move to the right, thereby driving the cleaning component 16 to clean the filter plate 14.

[0113] After the limiting component 15 moves to the right, it no longer restricts the sliding block 12. At this time, the continued extension of the first pushing member 6 will drive the sealing plate 11 to continue to move downward, thereby contacting the sliding block 12 and causing it to move downward. This will then drive the inclined plate 13 to move downward, so that the filter residue slides down and is discharged from the discharge port 18.

[0114] Compared with related technologies, the lithium recovery method and apparatus for cryogenic sodium precipitation and targeted extraction from high-sodium, low-lithium solutions provided by this invention have the following advantages:

[0115] The first extension of the first pusher 6 enables the switching from stirring to solid-liquid separation, which is simple and quick to operate. The second extension of the first pusher 6 drives the limiting component 15 to move to the right, thereby indirectly driving the cleaning component 16 to clean the filter plate 14, preventing the filter plate 14 from becoming clogged. The cleaning direction is opposite to the filtration direction of the filter plate 14, making unclogging easier and preventing damage to the filter plate 14 by filter residue. It also prevents the filter residue from forming dead ends inside the filter plate 14 (the filter residue accumulates and cannot be discharged through the forward water flow). The third extension of the first pusher 6 drives the inclined plate 13 to move downward, thereby allowing the filter residue to be discharged from the discharge port 18, which facilitates discharge. The whole operation is convenient and quick, and can achieve multiple state changes to meet different usage needs.

[0116] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A lithium recovery apparatus for cryogenic sodium precipitation and targeted extraction from a high-sodium, low-lithium solution, applied in step S4 of a lithium recovery method for cryogenic sodium precipitation and targeted extraction from a high-sodium, low-lithium solution, wherein the lithium recovery method for cryogenic sodium precipitation and targeted extraction from a high-sodium, low-lithium solution includes the following steps: S1. Weigh sodium sulfate and lithium sulfate samples, dissolve them in deionized water to prepare a high-sodium, low-lithium solution; S2. Determine the lithium ion and sodium ion content of the high-sodium, low-lithium solution by ICP-MS and atomic absorption spectrometry; S3. Freeze the high-sodium, low-lithium solution prepared in step S1 in a circulating refrigeration device to obtain a solid-liquid mixture; S4. Filter the solid-liquid mixture obtained in step S3 through a recovery device to obtain sodium sulfate crystals and a lithium-containing filtrate; S5. Add the lithium-containing filtrate obtained in step S4 to the recovery device and introduce CO2 gas to raise the temperature and precipitate lithium to obtain a solid-liquid mixture; S6. Filter the solid-liquid mixture obtained in step S5 through the recovery device again to obtain lithium sulfate crystals and a low-lithium filtrate. S7. Extracting the low-lithium filtrate obtained in step S6 using an extractant; characterized in that it includes a base; A housing is fixedly connected to the top of the base, and a reaction vessel is fixedly connected to the top of the housing. A stirring rod is rotatably connected to the reaction vessel. A connecting plate is fixedly connected to the top of the reaction vessel, and a first pushing member is mounted on the top of the connecting plate. A sliding plate is fixedly connected to the bottom of the first pushing member, and the first pushing member is used to drive the sliding plate to move linearly up and down. A connecting rod is fixedly connected to the bottom of the sliding plate, and the connecting rod passes through the stirring rod. A drive assembly is fixedly connected to the top of the housing, and the drive assembly is used to drive the stirring rod to rotate to achieve material stirring. The bottom of the reaction tank is provided with a discharge chute. A sealing plate is slidably connected inside the outer shell. The sealing plate is fixedly connected to a connecting rod. A sliding block is slidably connected inside the outer shell. An inclined plate is fixedly connected to the left side of the sliding block. A filter plate is installed on the left side of the outer shell. A limiting component is installed on the right side of the outer shell. The limiting component is used to support the sliding block. A cleaning component is installed on the limiting component. The cleaning component is used to clean the filter plate. A spring-loaded component is fixedly connected to the bottom of the outer shell. A discharge port is opened at the bottom of the outer shell. A collection chute is installed on the left side of the outer shell.

2. The lithium recovery device for cryogenic precipitation of sodium and targeted extraction from a high-sodium, low-lithium solution according to claim 1, characterized in that, The limiting component includes an L-shaped plate, a moving plate, an auxiliary block, a support block, and a first elastic element. The L-shaped plate is fixedly connected to the right side of the outer shell, the moving plate is slidably connected to the L-shaped plate, the auxiliary block is fixedly connected to the moving plate, the support block is fixedly connected to the moving plate, and the first elastic element is disposed between the moving plate and the L-shaped plate.

3. The lithium recovery device for cryogenic precipitation of sodium and targeted extraction from a high-sodium, low-lithium solution according to claim 2, characterized in that, The cleaning assembly includes a connecting frame, a mounting plate, and a plurality of cleaning needles. The connecting frame is fixedly connected to the moving plate, and the mounting plate is fixedly connected to the connecting frame. The plurality of cleaning needles are linearly distributed on the mounting plate, and the positions of the plurality of cleaning needles are aligned with the positions of the filter holes of the filter plate. The diameter of the cleaning needles is smaller than the diameter of the filter holes of the filter plate.

4. The lithium recovery device for cryogenic precipitation and targeted extraction from a high-sodium, low-lithium solution according to claim 3, characterized in that, The drive assembly includes a dual-axis motor, a worm gear, and a worm. The dual-axis motor is fixed to the reaction vessel, the worm gear is fixed to the outer surface of the stirring rod, and the worm is fixed to one of the output shafts of the dual-axis motor. The worm meshes with the worm gear.

5. The lithium recovery device for cryogenic precipitation and targeted extraction from a high-sodium, low-lithium solution according to claim 1, characterized in that, A suction pump is installed on the front of the outer casing. The inlet and outlet of the suction pump are both connected to delivery pipes. One delivery pipe is connected to the collection tank, and the other delivery pipe is connected to the reaction vessel.

6. The lithium recovery device for cryogenic precipitation and targeted extraction from a high-sodium, low-lithium solution according to claim 1, characterized in that, A support frame is fixedly connected to the right side of the outer casing, and a placement frame is fixedly connected to the top of the support frame. A lifting plate is slidably connected to the placement frame, and two bearing plates are installed on the placement frame. A conical disc is supported on the two bearing plates. A second pushing component is installed on the support frame, and a moving rod is fixedly connected to the second pushing component. The moving rod passes through the placement frame and the conical disc in sequence and is fixedly connected to the lifting plate. A support plate is fixedly connected to the moving rod. Multiple gas cylinders are placed on the conical disc. An air intake assembly is installed on the reaction tank, and a transmission assembly is installed on the placement frame.

7. The lithium recovery device for cryogenic precipitation and targeted extraction from a high-sodium, low-lithium solution according to claim 6, characterized in that, The air intake assembly includes an air intake pipe, a sleeve, and a connector. One end of the air intake pipe is connected to the reaction vessel. The sleeve is slidably connected to the other end of the air intake pipe and is fixedly connected to the lifting plate. The connector is fixedly connected to the sleeve and is inserted into the gas tank.

8. The lithium recovery device for cryogenic precipitation and targeted extraction from a high-sodium, low-lithium solution according to claim 7, characterized in that, The transmission assembly includes a fixed plate, a first transmission shaft, a second transmission shaft, two transmission wheels, a transmission belt, and a bevel gear. The fixed plate is fixedly connected to the mounting frame, the first transmission shaft is rotatably connected to the fixed plate, the second transmission shaft is mounted on the drive assembly, the two transmission wheels are respectively fixed to the first transmission shaft and the second transmission shaft, the transmission belt is disposed on the outer surface of the two transmission wheels, and the bevel gear is fixedly connected to the first transmission shaft.

9. The lithium recovery device for cryogenic sodium precipitation and targeted extraction from a high-sodium, low-lithium solution according to claim 8, characterized in that, The gas cylinder includes a cylinder body, a cylinder opening, a sealing piston, a second elastic element, and a gas outlet. The cylinder opening is located at the top of the cylinder body, the sealing piston is slidably connected inside the cylinder opening, the second elastic element is located at the bottom of the sealing piston, and the gas outlet is located on the cylinder opening.

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