An integrated device for deacidification and purification of lithium hexafluorophosphate

Abstract

This invention discloses an integrated device for the deacidification and purification of lithium hexafluorophosphate, relating to the field of chemical substance purification technology. It includes a deacidification tank comprising an outer cylinder and an inner cylinder, the inner cylinder being disposed within the inner cavity of the outer cylinder, with a reserved space between the two cylinders. The inner cylinder and outer cylinder are connected via an overflow port at the top of the inner cylinder. The inner cylinder is used to precipitate acidic impurities in the lithium hexafluorophosphate solution through chemical precipitation, while the outer cylinder is used to filter the precipitated lithium hexafluorophosphate solution. A purification tank, connected to the deacidification tank, includes a transfer chamber, a primary evaporation and concentration chamber, a secondary evaporation and concentration chamber, a tertiary evaporation and concentration chamber, and a cooling chamber, used to receive the filtered lithium hexafluorophosphate solution for tertiary evaporation and concentration. This invention integrates the deacidification and purification processes of lithium hexafluorophosphate into a single device, avoiding the cumbersome operation of multiple material transfers in traditional processes, significantly shortening the process flow and improving production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of chemical substance purification technology, specifically relating to an integrated device for the deacidification and purification of lithium hexafluorophosphate. Background Technology

[0002] Lithium hexafluorophosphate (LiPF6) is an important lithium salt widely used in the electrolytes of lithium-ion batteries. During the production process of LiPF6, due to factors such as the reactants and reaction conditions, the crude LiPF6 often contains various impurities. Among these, the presence of acidic impurities severely affects the quality and performance of LiPF6.

[0003] Currently, traditional lithium hexafluorophosphate purification processes typically separate the deacidification and purification processes, requiring multiple sets of equipment and numerous operational steps. This separate processing method not only involves complex processes and high equipment investment costs, but also easily introduces new impurities during multiple material transfers, reducing product purity. Furthermore, it increases production cycles and energy consumption, making it unsuitable for large-scale industrial production.

[0004] Chinese patent CN221244029U discloses a lithium hexafluorophosphate deacidification and purification device, comprising a tank, a receiving box fixedly connected inside the tank, a condenser tube fixedly connected inside the tank, and a liquid level sensing component for detecting the lithium hexafluorophosphate solution inside the receiving box movably connected to the inside of the receiving box. The receiving box stores a saturated lithium hexafluorophosphate solution, the condenser tube cools the lithium hexafluorophosphate solution, causing it to cool and crystallize inside the receiving box, and a filter hopper rises with the movement of the tank lid to filter and separate the lithium hexafluorophosphate crystals inside the receiving box. Simultaneously, an acid washing spray plate sprays deacidification liquid to clean the residual acid on the surface of the lithium hexafluorophosphate crystals, thus integrating the cooling, crystallization, and acid washing operations of lithium hexafluorophosphate, reducing the production cost and operational difficulty of lithium hexafluorophosphate deacidification and purification, and improving the production efficiency and yield of lithium hexafluorophosphate.

[0005] However, the deacidification process of the above-mentioned lithium hexafluorophosphate deacidification and purification device is to clean the residual acid on the surface of lithium hexafluorophosphate crystals by spraying deacidification liquid through an acid washing spray plate. This process cannot remove acidic impurities from lithium hexafluorophosphate, thereby reducing the purity of the product.

[0006] Therefore, developing a highly efficient device that can achieve integrated deacidification and purification of lithium hexafluorophosphate is of great practical significance. Summary of the Invention

[0007] The purpose of this invention is to address the problem that existing lithium hexafluorophosphate deacidification and purification devices have complex structures and cannot improve product purity, by providing an integrated lithium hexafluorophosphate deacidification and purification device.

[0008] This invention is achieved through the following technical solution: an integrated device for the deacidification and purification of lithium hexafluorophosphate, comprising:

[0009] A deacidification tank includes an outer cylinder and an inner cylinder. The inner cylinder is disposed in the inner cavity of the outer cylinder, and a space is reserved between the outer cylinder and the inner cylinder. The inner cavities of the outer cylinder and the inner cylinder are connected through an overflow port at the top of the inner cylinder. The inner cylinder is used to precipitate acid impurities in the lithium hexafluorophosphate solution by chemical precipitation, and the outer cylinder is used to filter the precipitated lithium hexafluorophosphate solution.

[0010] The purification tank, connected to the deacidification tank, includes a transfer chamber, a primary evaporation and concentration chamber, a secondary evaporation and concentration chamber, a tertiary evaporation and concentration chamber, and a cooling chamber. It is used to receive the filtered lithium hexafluorophosphate solution for tertiary evaporation and concentration, and to complete cooling and crystallization to obtain high-purity lithium hexafluorophosphate.

[0011] Preferably, the upper end of the outer cylinder is provided with two feeding pipes, namely a lithium hexafluorophosphate solution feeding pipe and a chemical reagent feeding pipe, and the lower ends of both feeding pipes are connected to the inner cavity of the inner cylinder; the lower end of the outer cylinder is provided with a discharge pipe, the upper end of which is connected to the inner cavity of the outer cylinder, and the lower end of which extends inward through the top of the transfer chamber.

[0012] Preferably, the deacidification tank is also provided with a stirring mechanism, which includes a stirring motor and a stirring assembly. The stirring motor is located on the top of the outer cylinder, and the stirring assembly is located inside the inner cylinder. The output end of the stirring motor passes through the top of the outer cylinder and is connected to the stirring assembly, driving the stirring assembly to complete the stirring action.

[0013] The stirring assembly is composed of multiple stirring tubes nested together. Each stirring tube has a receiving cavity inside. The adjacent lower stirring tube is movably disposed in the receiving cavity of the upper stirring tube. Each stirring tube has stirring blades on the lower part of its outer wall. The output end of the stirring motor is fixedly connected to the upper end of the uppermost stirring tube, and the lower end of the lowermost stirring tube is provided with a counterweight.

[0014] During stirring, the stirring tubes are fully stretched under the weight of the counterweight. At this time, the stirring motor starts and can drive all the stirring tubes to rotate at the same time. The rotation of the stirring blades on the stirring tubes can make the lithium hexafluorophosphate solution and chemical reagents fully mixed.

[0015] The outer wall of the stirring tube is provided with a limiting strip, and the inner wall of the receiving cavity of the stirring tube is provided with a limiting groove that matches the limiting strip on the adjacent stirring tube. During stirring, the engagement of the limiting strip and the limiting groove can ensure that all stirring tubes rotate at the same time.

[0016] Preferably, the inner cylinder has a lifting piston at the bottom of its inner cavity, and the lifting piston is sealed to the inner wall of the inner cylinder; the lower end of the inner cylinder has a pneumatic pump, and the outlet of the pneumatic pump is connected to the inner cavity of the inner cylinder; when the reacted lithium hexafluorophosphate solution needs to precipitate in the inner cylinder, after precipitation, the bottom of the inner cylinder is filled with air by the pneumatic pump, causing the lifting piston to rise, and the upper layer of precipitated lithium hexafluorophosphate solution is discharged into the outer cylinder through the overflow port, while the precipitate remains in the inner cylinder. At the same time as the lifting piston rises, the lifting piston supports the stirring tube at the lower end, causing the stirring tube above it to contract in the receiving cavity, which does not affect the lifting of the lifting piston.

[0017] Preferably, the inner cavity of the outer cylinder is provided with multiple filter screens, which are fixed by fixing blocks set on the inner wall of the outer cylinder; and the pore size of the multiple filter screens gradually decreases from top to bottom, for progressive filtration of lithium hexafluorophosphate solution.

[0018] Preferably, the purification tank is equipped with an internal track that runs through the transfer chamber, the primary evaporation and concentration chamber, the secondary evaporation and concentration chamber, the tertiary evaporation and concentration chamber, and the cooling chamber, and the track is equipped with a transport mechanism;

[0019] The transportation mechanism includes a transport vehicle, the lower end of which is mounted on a track by multiple wheels, and the upper end of which is fixedly connected to a support column. The upper end of the support column is provided with a transport platform, and a transport bucket is installed on the upper surface of the transport platform.

[0020] In use, the filtered lithium hexafluorophosphate solution is collected in a transport tank and then transported sequentially to the primary evaporation and concentration chamber, the secondary evaporation and concentration chamber, the tertiary evaporation and concentration chamber, and the cooling chamber by a transport vehicle.

[0021] Preferably, each of the primary, secondary, and tertiary evaporation and concentration chambers is equipped with an evaporation mechanism. The evaporation mechanism includes an evaporation chamber body located above the track. The evaporation chamber body has an evaporation cavity inside, and a heating pipe is provided on the inner wall of the evaporation cavity. The heating pipe is connected to a heater. The lower end of the evaporation chamber body has a transport opening. When the transport mechanism is in operation, the transport container moves within the evaporation cavity. The transport opening is used for the passage of the support column on the transport vehicle.

[0022] Preferably, the cooling chamber is equipped with cooling coils inside. The cooling coils are made of corrosion-resistant metal materials (such as stainless steel) and are distributed in a spiral or serpentine shape inside the cooling chamber. By introducing a low-temperature cooling medium (such as chilled brine, cold water, etc.) into the cooling coils, the heat of the material inside the chamber is removed by utilizing the principle of heat exchange.

[0023] Preferably, both ends of the purification tank are equipped with sealing doors, and a hydraulic drive device for driving the transport vehicle to move back and forth is installed on the sealing doors.

[0024] Preferably, partitions are provided between the transfer chamber and the primary evaporation and concentration chamber, and between the tertiary evaporation and concentration chamber and the cooling chamber. The partitions are provided with channels through which the transport mechanism passes. Slide grooves are provided on both sides of the channels. Partition gates are slidably installed in the slide grooves. The upper end of the partition gates penetrates the top of the purification tank. The partition gates are opened or closed by lifting them with handles on the upper part of the partition gates.

[0025] The present invention has the following advantages over the prior art:

[0026] 1. The device of the present invention integrates the deacidification and purification process of lithium hexafluorophosphate into one device, avoiding the cumbersome operation of transferring materials multiple times in the traditional process, greatly shortening the process flow and improving production efficiency.

[0027] 2. The deacidification tank in this invention is configured as a combination of an outer cylinder and an inner cylinder. The lithium hexafluorophosphate solution and chemical reagents react and precipitate through the inner cylinder. The precipitated lithium hexafluorophosphate solution is then automatically transferred to the outer cylinder for filtration, which reduces the number of equipment and operation steps, and lowers equipment investment costs and production energy consumption.

[0028] 3. The stirring assembly in this invention consists of multiple retractable stirring tubes, which can extend during stirring to promote the mixing of lithium hexafluorophosphate solution and chemical reagents. During transfer, it can retract under the support of the lifting piston, thus facilitating the transfer of the precipitated lithium hexafluorophosphate solution to the outer cylinder. At the same time, the retractable stirring tubes allow the inner cylinder to serve as both a reaction cylinder and a precipitation cylinder, saving equipment usage.

[0029] 4. The outer cylinder of the present invention is provided with multiple filter screens, and the pore size of the filter screens gradually decreases from top to bottom, which is used to perform progressive filtration of lithium hexafluorophosphate solution, thereby increasing the filtration effect and accuracy.

[0030] 5. The transport vehicle of this invention transports the filtered lithium hexafluorophosphate solution to the evaporation concentration chamber and the cooling chamber, thereby improving the transportation efficiency;

[0031] 6. The evaporation concentration chamber in this invention is divided into a primary evaporation concentration chamber, a secondary evaporation concentration chamber, and a tertiary evaporation concentration chamber, and the temperature of the three evaporation concentration chambers gradually increases, so that lithium hexafluorophosphate solution can be used for tertiary evaporation concentration, thereby improving the evaporation concentration effect.

[0032] 7. In this invention, partitions are provided between the transfer chamber and the primary evaporation and concentration chamber, as well as between the tertiary evaporation and concentration chamber and the cooling chamber. By lifting the partition gate, the transport channel can be opened or closed, which can prevent heat loss in the evaporation and concentration chamber and ensure the evaporation and concentration effect. Attached Figure Description

[0033] Figure 1 A schematic diagram of an integrated device for deacidification and purification of lithium hexafluorophosphate;

[0034] Figure 2 This is a schematic diagram of the purification tank in an integrated lithium hexafluorophosphate deacidification and purification device.

[0035] Figure 3 This is a schematic diagram of the deacidification tank in an integrated lithium hexafluorophosphate deacidification and purification device.

[0036] Figure 4 A cross-sectional view of the deacidification tank in an integrated lithium hexafluorophosphate deacidification and purification device;

[0037] Figure 5 This is an internal front view of the deacidification tank in an integrated lithium hexafluorophosphate deacidification and purification device;

[0038] Figure 6 This is a schematic diagram of the stirring component in an integrated lithium hexafluorophosphate deacidification and purification device.

[0039] Figure 7 This is a schematic diagram showing the storage of the stirring component in an integrated lithium hexafluorophosphate deacidification and purification device;

[0040] Figure 8 for Figure 2 A magnified structural diagram of A in the middle;

[0041] Figure 9 This is a schematic diagram of the transport mechanism in an integrated lithium hexafluorophosphate deacidification and purification device.

[0042] Figure 10 This is a schematic diagram of the bottom of the transport mechanism in an integrated lithium hexafluorophosphate deacidification and purification device.

[0043] The diagram is labeled as follows: 1. Purification tank; 2. Deacidification tank; 3. Support structure; 4. Sealing door; 5. Baffle gate; 6. Track; 7. Transport mechanism; 8. Evaporation mechanism; 9. Baffle; 10. Slide chute; 11. Hydraulic drive device.

[0044] 101. Transfer chamber; 102. Primary evaporation and concentration chamber; 103. Secondary evaporation and concentration chamber; 104. Tertiary evaporation and concentration chamber; 105. Cooling chamber;

[0045] 21. Outer cylinder; 22. Feeding pipe; 23. Stirring motor; 24. Discharge pipe; 25. Inner cylinder; 26. Stirring assembly; 27. Lifting piston; 28. Air pump; 29. ​​Overflow hole; 210. Filter screen; 211. Fixing block;

[0046] 261. Stirring tube; 262. Stirring blade; 263. Limiting strip; 264. Counterweight;

[0047] 701. Transport vehicle; 702. Support column; 703. Transport platform; 704. Transport container; 705. Wheel;

[0048] 801. Evaporation chamber; 802. Evaporation cavity; 803. Heating tube; 804. Transport opening. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] For examples, please refer to Figures 1-10 A lithium hexafluorophosphate deacidification and purification integrated device, comprising:

[0051] The deacidification tank 2 includes an outer cylinder 21 and an inner cylinder 25. The inner cylinder 25 is disposed inside the outer cylinder 21, and a space is reserved between the outer cylinder 21 and the inner cylinder 25. The inner cylinder 21 and the inner cylinder 25 are connected through an overflow port at the top of the inner cylinder 25. The inner cylinder 25 is used to precipitate acid impurities (such as hydrofluoric acid, phosphoric acid, etc.) in the lithium hexafluorophosphate solution by chemical precipitation. The outer cylinder 21 is used to filter the precipitated lithium hexafluorophosphate solution.

[0052] Purification tank 1, connected to deacidification tank 2, includes transfer chamber 101, primary evaporation concentration chamber 102, secondary evaporation concentration chamber 103, tertiary evaporation concentration chamber 104 and cooling chamber 105, used to receive the filtered lithium hexafluorophosphate solution for tertiary evaporation concentration and cooling crystallization to obtain high-purity lithium hexafluorophosphate.

[0053] In this embodiment, the upper end of the outer cylinder 21 is provided with two feeding pipes 22, one for lithium hexafluorophosphate solution and the other for chemical reagents, and the lower ends of both feeding pipes 22 are connected to the inner cavity of the inner cylinder 25. The lower end of the outer cylinder 21 is provided with a discharge pipe 24, the upper end of which is connected to the inner cavity of the outer cylinder 21, and the lower end of which extends inward through the top of the transfer chamber 101. The discharge pipe 24 is equipped with an electromagnetic valve (not shown in the figure) to control the discharge.

[0054] In use, the lithium hexafluorophosphate solution to be treated is added through the lithium hexafluorophosphate solution addition tube, and then the chemical reagent is slowly added through the chemical reagent addition tube to precipitate it; for example, adding a compound containing calcium ions (such as calcium carbonate, calcium hydroxide, etc.) will cause the calcium ions to react with phosphate ions to form calcium phosphate precipitate; adding silver ions (such as silver nitrate) will cause the silver ions to react with chloride ions to form silver chloride precipitate.

[0055] In this embodiment, the deacidification tank 2 is also provided with a stirring mechanism, which includes a stirring motor 23 and a stirring assembly 26. The stirring motor 23 is located on the top of the outer cylinder 21, and the stirring assembly 26 is located inside the inner cylinder 25. The output end of the stirring motor 23 passes through the top of the outer cylinder 21 and is connected to the stirring assembly 26, and drives the stirring assembly 26 to complete the stirring action.

[0056] Please see Figures 6-7 The stirring assembly 26 is composed of multiple stirring tubes 261 nested together. Each stirring tube 261 has a receiving cavity inside. The adjacent lower stirring tubes 261 are movably disposed in the receiving cavity of the upper stirring tube 261. Each stirring tube 261 has stirring blades 262 on the lower part of its outer wall. The output end of the stirring motor 23 is fixedly connected to the upper end of the uppermost stirring tube 261, and the lower end of the lowermost stirring tube 261 is provided with a counterweight 264.

[0057] During stirring, the stirring tube 261 is fully stretched under the gravity of the counterweight 264. At this time, the stirring motor 23 starts and can drive all the stirring tubes 261 to rotate at the same time. The rotation of the stirring blades on the stirring tube 261 can make the lithium hexafluorophosphate solution and chemical reagents fully mixed.

[0058] The outer wall of the stirring tube 261 is provided with a limiting strip 263, and the inner wall of the receiving cavity of the stirring tube 261 is provided with a limiting groove that matches the limiting strip 263 on the adjacent stirring tube 261. During stirring, the engagement of the limiting strip 263 and the limiting groove can ensure that all the stirring tubes 261 rotate at the same time.

[0059] In this embodiment, a lifting piston 27 is provided at the bottom of the inner cavity of the inner cylinder 25, and the lifting piston 27 is sealed to the inner wall of the inner cylinder 25; a pneumatic pump 28 is provided at the lower end of the inner cylinder 25, the outlet of the pneumatic pump 28 is connected to the inner cavity of the inner cylinder 25, and the inlet is connected to the outside of the outer cylinder; when the lithium hexafluorophosphate solution after reaction needs to precipitate in the inner cylinder 25, after precipitation, the pneumatic pump 28 is used to pressurize the bottom of the inner cylinder 25, so that the lifting piston 27 rises, and the upper layer of lithium hexafluorophosphate solution after precipitation is discharged into the outer cylinder 21 through the overflow port, while the precipitate remains in the inner cylinder 25. At the same time as the lifting piston 27 rises, the lifting piston 27 supports the stirring tube 261 at the lower end, so that the stirring tube 261 above it contracts in the receiving cavity, which does not affect the lifting of the lifting piston 27.

[0060] In this embodiment, the inner cavity of the outer cylinder 21 is provided with multiple filter screens 210, which are fixed by a fixing block 211 set on the inner wall of the outer cylinder 21; and the pore size of the multiple filter screens 210 gradually decreases from top to bottom, which is used for progressive filtration of lithium hexafluorophosphate solution.

[0061] In this embodiment, the purification tank 1 is provided with a track 6 inside, which runs through the transfer chamber 101, the primary evaporation and concentration chamber 102, the secondary evaporation and concentration chamber 103, the tertiary evaporation and concentration chamber 104 and the cooling chamber 105. The track 6 is provided with a transport mechanism 7.

[0062] The transport mechanism 7 includes a transport vehicle 701. The lower end of the transport vehicle 701 is rolled on the track 6 by multiple wheels 705. The upper end of the transport vehicle 701 is fixedly connected to a support column 702. The upper end of the support column 702 is provided with a transport platform 703. A transport bucket 704 is installed on the upper surface of the transport platform 703.

[0063] In use, the filtered lithium hexafluorophosphate solution is received by the transport tank 704, and the transport vehicle 701 transports the transport tank 704 sequentially to the primary evaporation and concentration chamber 102, the secondary evaporation and concentration chamber 103, the tertiary evaporation and concentration chamber 104, and the cooling chamber 105.

[0064] In this embodiment, each of the primary evaporation and concentration chamber 102, the secondary evaporation and concentration chamber 103, and the tertiary evaporation and concentration chamber 104 is equipped with an evaporation mechanism 8. The evaporation mechanism 8 includes an evaporation chamber body 801, which is located above the track 6. An evaporation chamber 802 is provided inside the evaporation chamber body 801, and a heating pipe 803 is provided on the inner wall of the evaporation chamber 802. The heating pipe 803 is connected to a heater. A transport opening 804 is provided at the lower end of the evaporation chamber body 801. When the transport mechanism 7 transports, the transport container 704 moves within the evaporation chamber 802. The transport opening 804 is used for the support column 702 on the transport vehicle 701 to pass through.

[0065] In this embodiment, the cooling chamber 105 is equipped with a cooling coil. The cooling coil is made of corrosion-resistant metal material such as stainless steel and is distributed in a spiral or serpentine shape inside the cooling chamber 105. By introducing a low-temperature cooling medium such as frozen brine or cold water into the cooling coil, the heat of the material in the chamber is removed by utilizing the principle of heat exchange.

[0066] In this embodiment, both ends of the purification tank 1 are provided with sealing doors 4. A hydraulic drive device 11 that drives the transport vehicle 701 to move back and forth is installed on the sealing door 4. The hydraulic drive device 11 can be a hydraulic cylinder or a coiled rope drive.

[0067] In this embodiment, partitions 9 are provided between the transfer chamber 101 and the primary evaporation and concentration chamber 102, the tertiary evaporation and concentration chamber 104 and the cooling chamber 105. The partitions 9 are provided with channels through which the transport mechanism 7 passes. Slide grooves 10 are provided on both sides of the channels of the partitions 9. Partition gates 5 are slidably provided in the slide grooves 10. The upper end of the partition gates 5 penetrates the top of the purification tank 1. The partition gates 5 are opened or closed by lifting the handles on the upper part of the partition gates 5.

[0068] Working principle of the invention:

[0069] First, a precise volume of crude lithium hexafluorophosphate solution is accurately measured and added into the inner cylinder 25 through the feed pipe 22. The stirring motor 23 is then started, and the stirring tube 261 is fully extended under the gravity of the counterweight 264, penetrating the entire upper and lower parts of the inner cylinder 25. Under stirring conditions, a precisely calculated amount of chemical precipitant solution is slowly added dropwise. During the dropwise addition process, the changes in the solution must be closely observed to ensure the reaction proceeds fully.

[0070] After the reaction is complete, the stirring motor 23 is turned off, and the mixture is allowed to stand in the inner cylinder 25 for a period of time to allow the precipitate to settle completely. Then, the bottom of the inner cylinder 25 is filled with air by the air pump 28, which raises the lifting piston 27 and discharges the upper layer of lithium hexafluorophosphate solution after precipitation into the outer cylinder 21 through the overflow port. The precipitate remains in the inner cylinder 25. At the same time as the lifting piston 27 rises, the lifting piston 27 supports the lower stirring tube 261, so that the upper stirring tube 261 contracts in the receiving cavity without affecting the lifting of the lifting piston 27.

[0071] Then, the lithium hexafluorophosphate solution is filtered through multiple filter screens 210 inside the outer cylinder 21 to separate the precipitate. The filtered lithium hexafluorophosphate solution enters the transport tank 704 inside the purification tank 1, and is then transported sequentially by the transport vehicle 701 to the primary evaporation concentration chamber 102, the secondary evaporation concentration chamber 103, and the tertiary evaporation concentration chamber 104. After evaporation and concentration, it is then transported to the cooling chamber 105 for cooling and crystallization treatment to obtain preliminarily purified lithium hexafluorophosphate crystals.

[0072] When the sediment in the inner cylinder 25 needs to be cleaned, clean water is injected into the inner cylinder 25 and the stirring motor 23 is started to stir, so that the sediment and water are mixed. Then, the mixture is lifted by the lifting piston 27 and discharged into the outer cylinder, entering the transport tank 704. The sealing door 4 of the transfer chamber 101 is opened to discharge the rinsed mixture, thus maintaining the purification effect of the device.

[0073] The device of the present invention integrates the deacidification and purification process of lithium hexafluorophosphate into one device, avoiding the cumbersome operation of multiple material transfers in the traditional process, greatly shortening the process flow and improving production efficiency.

[0074] The deacidification tank 2 in this invention is configured as a combination of an outer cylinder 21 and an inner cylinder 25. The lithium hexafluorophosphate solution and chemical reagents react and precipitate through the inner cylinder 25. The precipitated lithium hexafluorophosphate solution is then automatically transferred to the outer cylinder 21 for filtration, which reduces the number of equipment and operation steps, and lowers equipment investment costs and production energy consumption.

[0075] The stirring assembly 26 in this invention is composed of multiple retractable stirring tubes 261, which can extend during stirring to promote the mixing of lithium hexafluorophosphate solution and chemical reagents. During transfer, it can retract under the support of the lifting piston 27, thereby facilitating the transfer of the precipitated lithium hexafluorophosphate solution to the outer cylinder 21 by the lifting piston 27. At the same time, the retractable stirring tubes allow the inner cylinder to serve as both a reaction cylinder and a precipitation cylinder, saving equipment usage.

[0076] The outer cylinder 21 of the present invention is provided with a plurality of filter screens 210, and the pore size of the filter screens 210 gradually decreases from top to bottom, which is used to perform progressive filtration of lithium hexafluorophosphate solution, thereby increasing the filtration effect and accuracy.

[0077] The transport vehicle 701 of this invention transports the filtered lithium hexafluorophosphate solution to the evaporation concentration chamber and the cooling chamber 105, thereby improving the efficiency of transportation.

[0078] The evaporation and concentration chamber in this invention is divided into a primary evaporation and concentration chamber 102, a secondary evaporation and concentration chamber 103, and a tertiary evaporation and concentration chamber 104. The temperature of the three evaporation and concentration chambers gradually increases, which can perform tertiary evaporation and concentration of lithium hexafluorophosphate solution to improve the evaporation and concentration effect.

[0079] In this invention, partitions 9 are provided between the transfer chamber 101 and the primary evaporation and concentration chamber 102, the tertiary evaporation and concentration chamber 104 and the cooling chamber 105. By lifting the partition gate 5, the transport channel can be opened or closed, which can prevent heat loss in the evaporation and concentration chamber and ensure the evaporation and concentration effect.

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the phrase "comprising an element defined as..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0081] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An integrated device for deacidification and purification of lithium hexafluorophosphate, characterized in that, include: A deacidification tank (2) includes an outer cylinder (21) and an inner cylinder (25). The inner cylinder (25) is disposed in the inner cavity of the outer cylinder (21), and a space is reserved between the outer cylinder (21) and the inner cylinder (25). The inner cavities of the outer cylinder (21) and the inner cylinder (25) are connected through the overflow port at the top of the inner cylinder (25). The inner cylinder (25) is used to precipitate acid impurities in the lithium hexafluorophosphate solution by chemical precipitation, and the outer cylinder (21) is used to filter the precipitated lithium hexafluorophosphate solution. Purification tank (1), which is connected to deacidification tank (2), includes transfer chamber (101), primary evaporation concentration chamber (102), secondary evaporation concentration chamber (103), tertiary evaporation concentration chamber (104) and cooling chamber (105), used to receive the filtered lithium hexafluorophosphate solution for tertiary evaporation concentration and cooling crystallization to obtain high-purity lithium hexafluorophosphate; The purification tank (1) is equipped with a track (6) inside, which runs through the transfer chamber (101), the primary evaporation and concentration chamber (102), the secondary evaporation and concentration chamber (103), the tertiary evaporation and concentration chamber (104) and the cooling chamber (105). A transport mechanism (7) is provided on the track (6). The transport mechanism (7) includes a transport vehicle (701), the lower end of which is rolled on a track (6) by multiple wheels (705), the upper end of which is fixedly connected to a support column (702), the upper end of which is provided with a transport platform (703), and the upper surface of the transport platform (703) is equipped with a transport bucket (704). The first-stage evaporation and concentration chamber (102), the second-stage evaporation and concentration chamber (103), and the third-stage evaporation and concentration chamber (104) are all equipped with evaporation mechanisms (8). The evaporation mechanism (8) includes an evaporation chamber body (801), which is located above the track (6). The evaporation chamber body (801) has an evaporation chamber (802) inside, and a heating pipe (803) is provided on the inner wall of the evaporation chamber (802). The heating pipe (803) is connected to a heater. The lower end of the evaporation chamber body (801) is provided with a transport opening (804). When the transport mechanism (7) transports, the transport barrel (704) moves inside the evaporation chamber (802), and the transport opening (804) is used for the support column (702) on the transport vehicle (701) to pass through.

2. The integrated lithium hexafluorophosphate deacidification and purification device according to claim 1, characterized in that, The upper end of the outer cylinder (21) is provided with a feeding pipe (22), which consists of two pipes: a lithium hexafluorophosphate solution feeding pipe and a chemical reagent feeding pipe. The lower ends of both feeding pipes (22) are connected to the inner cavity of the inner cylinder (25). The lower end of the outer cylinder (21) is provided with a discharge pipe (24), the upper end of which is connected to the inner cavity of the outer cylinder (21), and the lower end of which extends inward through the top of the transfer chamber (101).

3. The integrated lithium hexafluorophosphate deacidification and purification device according to claim 1, characterized in that, The deacidification tank (2) is also provided with a stirring mechanism, which includes a stirring motor (23) and a stirring assembly (26). The stirring motor (23) is located on the top of the outer cylinder (21), and the stirring assembly (26) is located inside the inner cylinder (25). The output end of the stirring motor (23) passes through the top of the outer cylinder (21) and is connected to the stirring assembly (26), and drives the stirring assembly (26) to complete the stirring action. The stirring assembly (26) is composed of multiple stirring tubes (261) nested together. Each stirring tube (261) has a receiving cavity inside. The adjacent lower stirring tube (261) is movably disposed in the receiving cavity of the upper stirring tube (261). Each stirring tube (261) has a stirring blade (262) on the lower part of its outer wall. The output end of the stirring motor (23) is fixedly connected to the upper end of the uppermost stirring tube (261), and the lower end of the lowermost stirring tube (261) is provided with a counterweight (264). The outer wall of the stirring tube (261) is provided with a limiting strip (263), and the inner wall of the receiving cavity of the stirring tube (261) is provided with a limiting groove that matches the limiting strip (263) on the adjacent stirring tube (261). During stirring, the engagement of the limiting strip (263) and the limiting groove can ensure that all the stirring tubes (261) rotate at the same time.

4. The integrated lithium hexafluorophosphate deacidification and purification device according to claim 3, characterized in that, The inner cylinder (25) has a lifting piston (27) at the bottom of its inner cavity, and the lifting piston (27) is sealed to the inner wall of the inner cylinder (25). The lower end of the inner cylinder (25) is equipped with a pneumatic pump (28), and the outlet of the pneumatic pump (28) is connected to the inner cavity of the inner cylinder (25). When the lithium hexafluorophosphate solution after the reaction needs to precipitate in the inner cylinder (25), after the precipitation is completed, the pneumatic pump (28) is used to pressurize the bottom of the inner cylinder (25), so that the lifting piston (27) rises and discharges the upper layer of lithium hexafluorophosphate solution after precipitation into the outer cylinder (21) through the overflow port. The precipitate remains in the inner cylinder (25). While the lifting piston (27) rises, the lifting piston (27) supports the stirring tube (261) at the lower end, so that the stirring tube (261) above it contracts in the receiving cavity, which will not affect the lifting of the lifting piston (27).

5. The integrated lithium hexafluorophosphate deacidification and purification device according to claim 1, characterized in that, The inner cavity of the outer cylinder (21) is provided with multiple filter screens (210), which are fixed by fixed blocks (211) set on the inner wall of the outer cylinder (21); and the aperture of the multiple filter screens (210) gradually decreases from top to bottom, which is used for progressive filtration of lithium hexafluorophosphate solution.

6. The integrated lithium hexafluorophosphate deacidification and purification device according to claim 1, characterized in that, The cooling chamber (105) is equipped with cooling coils inside, which are made of corrosion-resistant metal material and are distributed in a spiral or serpentine shape inside the cooling chamber (105).

7. The integrated lithium hexafluorophosphate deacidification and purification device according to claim 1, characterized in that, Both ends of the purification tank (1) are equipped with sealing doors (4), and the sealing doors (4) are equipped with hydraulic drive devices that drive the carrier (701) to move back and forth.

8. The integrated lithium hexafluorophosphate deacidification and purification device according to claim 1, characterized in that, The transfer chamber (101) and the first-stage evaporation and concentration chamber (102), the third-stage evaporation and concentration chamber (104) and the cooling chamber (105) are all provided with partitions (9). The partitions (9) are provided with channels through which the transport mechanism (7) passes. The partitions (9) are provided with grooves (10) on both sides of the channels. The partition gates (5) are slidably provided in the grooves (10). The upper end of the partition gates (5) penetrates the top of the purification tank (1). The partition gates (5) are lifted by the handles on the upper part of the partition gates (5) to open or close the transport channel.

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