Liquid lithium hexafluorophosphate synthesis device

Abstract

The utility model discloses a liquid lithium hexafluorophosphate synthesis device which comprises a preparation kettle, a synthesis kettle and a refining kettle, a lithium fluoride feed port, a solvent feed port, a lithium fluoride content measuring device, an online thermometer A and an observation port are arranged at the top of the preparation kettle; the top of the synthesis kettle is provided with a preparation liquid feeding hole, a phosphorus pentafluoride gas inlet, a lithium hexafluorophosphate content measuring device A, a radar liquid level meter, an online thermometer B and a gas outlet; the top of the refining kettle is provided with a synthesis liquid feeding hole, a solvent feeding hole and a lithium hexafluorophosphate content measuring device B; the preparation kettle is connected with the synthesis kettle through an on-line liquid flow meter B, and the synthesis kettle is connected with the refining kettle through a filtering device, a material transfer pump and an on-line liquid flow meter C; the phosphorus pentafluoride gas inlet is connected with a phosphorus pentafluoride gas inlet pipeline through an on-line gas flowmeter, the phosphorus pentafluoride gas inlet extends into the bottom of the synthesis kettle, and a gas distributor is arranged at the tail end of the phosphorus pentafluoride gas inlet; the utility model has the advantages of high production efficiency, good product quality and low product storage and transportation risk.

Description

Technical Field

[0001] This utility model belongs to the field of liquid lithium hexafluorophosphate production technology, specifically relating to a liquid lithium hexafluorophosphate synthesis device. Background Technology

[0002] Lithium hexafluorophosphate (LiPF6) is an inorganic compound, a white crystalline powder. It is readily soluble in water and also soluble in low-concentration methanol, ethanol, acetone, carbonates, and other organic solvents. It is the most important component of electrolytes, accounting for approximately 43% of the total electrolyte cost. As a lithium-ion battery electrolyte, LiPF6 is mainly used in lithium-ion power batteries, lithium-ion energy storage batteries, and other everyday batteries, and is an irreplaceable lithium-ion battery electrolyte in the near to medium term. With the continued expansion of the new energy sector, LiPF6 is expected to experience sustained growth.

[0003] There are many methods for synthesizing lithium hexafluorophosphate. However, generally speaking, the methods used in actual production fall into two main categories: dry methods and wet methods. The dry method uses calcium fluoride, phosphorus pentoxide, and lithium fluoride as raw materials to synthesize lithium hexafluorophosphate under high temperature and pressure. The reaction conditions are harsh and difficult to control, resulting in poor safety, a high risk factor, and weak production continuity; therefore, it is rarely used in actual production. The wet method uses anhydrous hydrogen fluoride as a solvent to synthesize lithium hexafluorophosphate and is currently the mainstream production method, used by most companies in actual production, accounting for more than 50% of existing capacity. These two methods for synthesizing lithium hexafluorophosphate (LiPF6) are mainly used for solid-state LiPF6 synthesis. The main synthesis methods include gas-solid reaction, HF solvent method, organic solvent method, and ion exchange method. However, the production process of LiPF6 involves many steps, complex processes, high equipment requirements, and stringent reaction conditions, resulting in low product purity and complex purification. There are also certain drawbacks in the storage and transportation of LiPF6, such as demanding storage and transportation conditions and high risk. Furthermore, traditional LiPF6 production methods require cooling crystallization and heating drying, which increases costs to some extent. Therefore, it is necessary to change the traditional production mode and equipment for LiPF6. Compared with solid-state LiPF6, liquid LiPF6 not only has the advantages of stable storage and convenient transportation, but can also be directly used in lithium-ion battery electrolytes without dissolution. Therefore, designing a liquid LiPF6 synthesis device is of great practical significance for reducing the industrialization cost of lithium-ion batteries and improving market competitiveness. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a liquid lithium hexafluorophosphate synthesis device with high production efficiency, good product quality, and low product storage and transportation risks.

[0005] The purpose of this utility model is achieved as follows: A liquid lithium hexafluorophosphate synthesis device includes a preparation vessel, a synthesis vessel and a refining vessel located below the preparation vessel. The top of the preparation vessel is provided with a lithium fluoride inlet, a solvent inlet, a lithium fluoride content measuring device, an online thermometer A and an observation port. The top of the synthesis vessel is provided with a preparation liquid inlet, a phosphorus pentafluoride gas inlet, a lithium hexafluorophosphate content measuring device A, a radar level gauge, an online thermometer B and an exhaust port. The top of the refining vessel is provided with a synthesis liquid inlet, a solvent inlet and a lithium hexafluorophosphate content measuring device B.

[0006] The discharge port at the bottom of the preparation vessel is connected to the inlet of the preparation liquid via an online liquid flow meter B. The discharge port at the bottom of the synthesis vessel is connected to the inlet of the synthesis liquid via a filter device, a transfer pump, and an online liquid flow meter C. The discharge port at the bottom of the refining vessel is connected to a discharge pipe.

[0007] The solvent inlet is connected to a solvent inlet pipe, and an online liquid flow meter A is installed on the solvent inlet pipe; the phosphorus pentafluoride inlet is connected to a phosphorus pentafluoride inlet pipe, and an online gas flow meter is installed on the phosphorus pentafluoride inlet pipe; the phosphorus pentafluoride inlet is connected to a phosphorus pentafluoride inlet pipe, and a gas distributor is installed after the phosphorus pentafluoride inlet pipe extends into the bottom of the synthesis reactor; the solvent feed inlet is connected to a solvent feed pipe, and an online liquid flow meter D is installed on the solvent feed pipe.

[0008] Preferably, the preparation vessel, the synthesis vessel, and the refining vessel are all equipped with a stirring motor and a stirrer. The stirring motor is installed above the vessel body, and the stirrer of the synthesis vessel is located above the gas distributor.

[0009] Preferably, the stirring motor of the synthesis reactor is a servo frequency converter motor. The servo frequency converter motor is equipped with an adjustment switch and connected to a remote control system. The motor speed can be manually adjusted and remotely controlled. The servo frequency converter motor is equipped with a wire mesh for protection.

[0010] Preferably, the preparation vessel, the synthesis vessel, and the refining vessel are all made of 304 stainless steel.

[0011] Preferably, level gauges are installed on the sides of the preparation vessel, the synthesis vessel, and the refining vessel.

[0012] Preferably, the lithium fluoride inlet, the solvent inlet, the preparation liquid inlet, the phosphorus pentafluoride inlet, the exhaust port, the synthesis liquid inlet, the solvent feeding port, and the discharge ports at the bottom of the preparation vessel, the bottom of the synthesis vessel, and the bottom of the refining vessel are all equipped with control valves.

[0013] Preferably, the control valve of the phosphorus pentafluoride inlet is equipped with an electric valve positioner.

[0014] Preferably, the synthesis vessel is provided with a cooling water jacket and a matching cooling water inlet and cooling water outlet, and the vessel body is provided with heat insulation material.

[0015] Preferably, the observation port is fitted with explosion-proof glass.

[0016] Due to the adoption of the above technical solutions, the beneficial effects of this utility model are:

[0017] This invention employs a preparation vessel, a synthesis vessel, and a refining vessel to separately complete the mixing of lithium fluoride and electrolyte solvent, the reaction of lithium fluoride in the mixture with phosphorus pentafluoride gas-liquid contact to synthesize crude liquid lithium hexafluorophosphate, and the further mixing of the crude liquid lithium hexafluorophosphate with electrolyte solvent to refine the liquid lithium hexafluorophosphate. It can replace the original solid lithium hexafluorophosphate production equipment for the production of liquid lithium hexafluorophosphate, greatly reducing the risks in production, as well as the risks in storage and transportation. The product can be directly used in the preparation of lithium-ion battery electrolytes, improving production efficiency.

[0018] This invention employs a lithium fluoride content measuring device, a lithium hexafluorophosphate content measuring device, a radar level gauge, an online thermometer, and an online liquid flow meter to control the amount of reaction raw materials and the synthesis reaction temperature, effectively ensuring product quality. It also utilizes a gas distributor extending deep into the reactor bottom to disperse the introduced phosphorus pentafluoride gas, making the synthesis reaction more complete and smoother, resulting in higher production efficiency and better product quality. Finally, it incorporates a filtration device for filtering impurities before refining, further improving product quality.

[0019] In summary, this utility model has the advantages of high production efficiency, good product quality, and low risks in product storage and transportation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the device composition of this utility model.

[0021] In the diagram: 1. Preparation vessel; 2. Lithium fluoride inlet; 3. Lithium fluoride content measuring device; 4. Stirring motor; 5. Online thermometer A; 6. Solvent inlet; 7. Online liquid flow meter A; 8. Solvent inlet pipe; 9. Observation port; 10. Stirrer; 11. Radar level gauge; 12. Online liquid flow meter B; 13. Preparation liquid inlet; 14. Lithium hexafluorophosphate content measuring device A; 15. Wire mesh protection; 16. Online thermometer B; 17. Exhaust port; 18. Online gas flow meter; 19. Phosphorus pentafluoride inlet pipe; 20. Phosphorus pentafluoride inlet; 21. Phosphorus pentafluoride inlet pipe; 22. Gas distributor; 23. Filter device; 24. Transfer pump; 25. Online liquid flow meter C; 26. Synthesis liquid inlet; 27. Lithium hexafluorophosphate content measuring device B; 28. Solvent inlet; 29. ​​Online liquid flow meter D. 30. Solvent feeding pipe; 31. Discharge pipe; 32. Refining kettle; 33. Synthesis kettle; 34. Level gauge; 35. Control valve. Detailed Implementation

[0022] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings.

[0023] like Figure 1 As shown, this utility model provides a liquid lithium hexafluorophosphate synthesis device, which is mainly used to solve the problems of low product purity, complicated purification, high transportation and storage conditions, high danger, and inability to be used directly when producing solid lithium hexafluorophosphate products by existing dry and wet methods. The produced liquid lithium hexafluorophosphate product can be directly used as a lithium-ion battery electrolyte, which can reduce transportation and storage costs and risk factors.

[0024] The synthesis apparatus of this invention includes a preparation vessel 1 for mixing lithium fluoride with an electrolyte solvent, a synthesis vessel 33 for reacting lithium fluoride with phosphorus pentafluoride to synthesize crude liquid lithium hexafluorophosphate, and a refining vessel 32 for mixing crude liquid lithium hexafluorophosphate with an electrolyte solvent. The main function is to carry out a gas-liquid contact reaction between phosphorus pentafluoride and lithium fluoride to prepare liquid lithium hexafluorophosphate.

[0025] The main body of the preparation vessel 1 is a stirred vessel made of 304 stainless steel. A level gauge 34 is installed on the side of the vessel, and a stirring motor 4 is installed on the top, connected to a stirrer 10. The stirrer 10 can be a common frame stirrer, paddle stirrer, etc. The lid of the stirred vessel is equipped with a lithium fluoride inlet 2, a solvent inlet 6, and an observation port 9. The solvent inlet 6 is connected to a solvent inlet pipe 8, and an online liquid flow meter A7 is installed on the solvent inlet pipe 8. An explosion-proof glass is installed on the observation port 9. The lid of the stirred vessel is also equipped with an online thermometer A5 and a lithium fluoride content measuring device 3, which are used to measure the temperature inside the vessel and the lithium fluoride content in the prepared solution, respectively. The bottom of the stirred vessel is a discharge port, which is connected to the preparation solution inlet 13 of the synthesis vessel 33 through an online liquid flow meter B12.

[0026] There are many existing devices for determining the content of lithium fluoride. For example, the device used in the fluoride ion selective electrode method can be an ion analyzer and a fluoride ion selective electrode; if the spectroscopic method is used, an ultraviolet or visible light spectrometer can be used; if the flame photometry method is used, a flame photometer can be used; all of the above can be used to determine the content of lithium fluoride.

[0027] The synthesis reactor 33 is made of 304 stainless steel. A stirrer 10 is installed on the reactor 33, and the stirring motor 4 mounted on top is a servo frequency converter motor. The servo frequency converter motor has an adjustment switch and is connected to a remote control system. The motor speed can be manually and remotely adjusted. A wire mesh protective net 15 is added to the servo frequency converter motor for safety and reliability. The reactor 33 has insulation material on its exterior and is equipped with a cooling water jacket with cooling water inlet and outlet. A level gauge 34 is installed on the side of the reactor body. The reactor lid has a preparation liquid inlet 13, a phosphorus pentafluoride air inlet 20, and an exhaust outlet 17. The phosphorus pentafluoride inlet 20 is externally connected to the phosphorus pentafluoride feed pipe 19. An online gas flow meter 18 and a control valve 35 are installed on the phosphorus pentafluoride inlet pipe 19. The control valve 35 is equipped with an electric valve positioner to accurately control and regulate the intake volume of phosphorus pentafluoride gas. Internally, the phosphorus pentafluoride inlet 20 is connected to a phosphorus pentafluoride inlet pipe 21, which extends to the bottom of the reactor and ends at a gas distributor 22 located below the stirrer 10 for more complete reaction. The exhaust port 17 is used to connect to an external tail gas treatment device for absorption treatment or collection and recycling of tail gas. An online thermometer B16, a lithium hexafluorophosphate content measuring device A14, and a radar level gauge 11 are installed on the reactor lid of the synthesis reactor for accurate analysis and measurement of the synthesis reaction inside the reactor, to understand the synthesis status and yield of liquid lithium hexafluorophosphate. The online thermometer B16 has a remote function and can be used together with cooling water to accurately adjust and control the synthesis reaction temperature to prevent abnormal temperature conditions. The bottom of the synthesis vessel 33 is a discharge port, which is connected to the synthesis liquid inlet 26 of the refining vessel 32 through a filter device 23, a transfer pump 24, and an online liquid flow meter C25. The filter device 23 is used to filter impurities in the synthesis liquid to improve product quality.

[0028] The refining reactor 32 is used to precisely prepare crude liquid lithium hexafluorophosphate to produce liquid lithium hexafluorophosphate of standard concentration. The refining reactor 32 is made of 304 stainless steel. A stirring motor 4 is installed on the top of the reactor lid, connected to a stirrer 10. A level gauge 34 is installed on the side of the reactor body, and a synthesis liquid inlet 26 is provided on the reactor lid. A lithium hexafluorophosphate content measuring device B27 is also installed on the lid of the refining reactor 32, and a solvent feeding port 28 is provided, connected to a solvent feeding pipe 30. An online liquid flow meter D29 is installed on the solvent feeding pipe 30 to ensure accurate analysis and qualification of the liquid lithium hexafluorophosphate product. A discharge port is provided at the bottom of the refining reactor 32, connected to a discharge pipe 31, for discharging the qualified liquid lithium hexafluorophosphate product.

[0029] There are many existing devices for determining the content of lithium hexafluorophosphate, such as potentiometric titration, which uses a fully automatic potentiometric titrator, such as JH-T7 and CT-1Plus; ion chromatography, which uses an ion chromatograph; and other instruments such as inductively coupled plasma atomic emission spectrometer and graphite furnace atomic absorption spectrometer.

[0030] The lithium fluoride inlet 2, solvent inlet 6, preparation liquid inlet 13, phosphorus pentafluoride inlet 20, exhaust port 17, synthesis liquid inlet 26, solvent feeding port 28, and discharge ports at the bottom of preparation vessel 1, synthesis vessel 33, and refining vessel 32 are all equipped with control valves 35, which can be adjusted and controlled on-site and remotely.

[0031] The instruments and meters used in this utility model include a lithium fluoride content measuring device 3, an online liquid flow meter A7, a lithium hexafluorophosphate content measuring device A14, an online gas flow meter 18, etc., all of which have remote transmission functions. The data is sent to the remote control system. The remote control system remotely controls and adjusts the corresponding control valves 35 according to the detection data of each instrument and meter, thereby controlling and adjusting the inflow or outflow of the corresponding material.

[0032] After the above installation is completed, this utility model can be put into use. Start the stirrer 10 of the preparation vessel 1, add the set mass of lithium fluoride into the preparation vessel 1 through the lithium fluoride inlet 2, and add the set mass of electrolyte solvent into the preparation vessel 1 through the solvent inlet 6. The stirrer 10 stirs and mixes the two. During this period, the lithium content measuring device 3 detects the lithium fluoride content in the preparation solution until the lithium fluoride content reaches the preset value and remains basically unchanged, indicating that the lithium fluoride and electrolyte solvent are mixed evenly and the preparation work is completed.

[0033] Start the stirrer 10 of the synthesis vessel 33, open the control valve 35 of the bottom discharge port of the preparation vessel 1, and the preparation liquid flows into the synthesis vessel 33 from the preparation liquid inlet 13. The online liquid flow meter B12 detects the flow rate of the preparation liquid. After the set flow rate is reached or all the liquid has flowed in, close the control valve 35 of the bottom discharge port of the preparation vessel 1. Then, phosphorus pentafluoride gas is introduced into the synthesis vessel 33 through the phosphorus pentafluoride inlet pipe 19, phosphorus pentafluoride inlet 20, phosphorus pentafluoride inlet pipe 21, and gas distributor 22 to carry out gas-liquid contact reaction with lithium fluoride in the preparation liquid. During this period, the lithium hexafluorophosphate content measuring device A detects the lithium hexafluorophosphate content in the reaction liquid until the lithium hexafluorophosphate content reaches the preset value and remains basically unchanged, indicating that the gas-liquid contact reaction is completed. Close the control valve 35 of the phosphorus pentafluoride inlet 20. During this period, the phosphorus pentafluoride gas that did not participate in the reaction is discharged from the exhaust port 17 along with other gases.

[0034] Start the stirrer 10 of the refining vessel 32, open the control valve 35 of the bottom discharge port of the synthesis vessel 33, start the transfer pump 24, and pump the reaction-treated synthesis liquid into the refining vessel 32. The online liquid flow meter C25 detects the amount of synthesis liquid pumped in. After the set pumping amount is reached, close the control valve 35 of the bottom discharge port of the synthesis vessel 33. Then, the set amount of electrolyte solvent is added into the refining vessel 32 through the solvent feeding pipe 30 and the solvent feeding port 28. After the addition is completed, close the control valve 35 of the solvent feeding port 28. The stirrer 10 stirs and mixes the electrolyte solvent and the synthesis liquid. During this period, the lithium hexafluorophosphate content measuring device B27 detects the lithium hexafluorophosphate content of the mixture until the lithium hexafluorophosphate content remains basically unchanged. The detection data is compared with the standard concentration. If the content is high, add more electrolyte solvent; if the content is low, add more synthesis liquid. The amount added can be calculated by the difference between the detection data and the standard concentration. After adding, continue stirring and mixing until the detection data remains basically unchanged and reaches the threshold range of the standard concentration. The refining work is completed.

[0035] Finally, open the control valve 35 at the bottom discharge port of the refining vessel 32, and obtain qualified liquid lithium hexafluorophosphate product from the discharge pipe 31.

[0036] In summary, the synthesis apparatus of this invention for producing liquid lithium hexafluorophosphate significantly improves product purity, reduces risks and costs in transportation and storage, ensures accurate control and analysis during production, has a high degree of automation, and the produced product can be directly used in the preparation of lithium-ion battery electrolytes, thus improving production efficiency.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A liquid lithium hexafluorophosphate synthesis apparatus, characterized in that: The apparatus includes a preparation vessel, a synthesis vessel located below the preparation vessel, and a refining vessel. The top of the preparation vessel is equipped with a lithium fluoride inlet, a solvent inlet, a lithium fluoride content measuring device, an online thermometer A, and an observation port. The top of the synthesis vessel is equipped with a preparation liquid inlet, a phosphorus pentafluoride gas inlet, a lithium hexafluorophosphate content measuring device A, a radar level gauge, an online thermometer B, and an exhaust port. The top of the refining vessel is equipped with a synthesis liquid inlet, a solvent inlet, and a lithium hexafluorophosphate content measuring device B. The discharge port at the bottom of the preparation vessel is connected to the inlet of the preparation liquid via an online liquid flow meter B. The discharge port at the bottom of the synthesis vessel is connected to the inlet of the synthesis liquid via a filter device, a transfer pump, and an online liquid flow meter C. The discharge port at the bottom of the refining vessel is connected to a discharge pipe. The solvent inlet is connected to a solvent inlet pipe, and an online liquid flow meter A is installed on the solvent inlet pipe; the phosphorus pentafluoride inlet is connected to a phosphorus pentafluoride inlet pipe, and an online gas flow meter is installed on the phosphorus pentafluoride inlet pipe; the phosphorus pentafluoride inlet is connected to a phosphorus pentafluoride inlet pipe, and a gas distributor is installed after the phosphorus pentafluoride inlet pipe extends into the bottom of the synthesis reactor; the solvent feed inlet is connected to a solvent feed pipe, and an online liquid flow meter D is installed on the solvent feed pipe.

2. The liquid lithium hexafluorophosphate synthesis apparatus according to claim 1, characterized in that: The preparation vessel, the synthesis vessel, and the refining vessel are all equipped with a stirring motor and a stirrer. The stirring motor is installed above the vessel body, and the stirrer of the synthesis vessel is located above the gas distributor.

3. The liquid lithium hexafluorophosphate synthesis apparatus according to claim 2, characterized in that: The stirring motor of the synthesis reactor is a servo frequency converter motor. The servo frequency converter motor is equipped with an adjustment switch and is connected to a remote control system. The motor speed can be adjusted manually and remotely. The servo frequency converter motor is equipped with a wire mesh for protection.

4. The liquid lithium hexafluorophosphate synthesis apparatus according to claim 1, characterized in that: The preparation vessel, the synthesis vessel, and the refining vessel are all made of 304 stainless steel.

5. The liquid lithium hexafluorophosphate synthesis apparatus according to claim 1, characterized in that: Level gauges are installed on the sides of the preparation vessel, the synthesis vessel, and the refining vessel.

6. The liquid lithium hexafluorophosphate synthesis apparatus according to claim 1, characterized in that: The lithium fluoride inlet, the solvent inlet, the preparation liquid inlet, the phosphorus pentafluoride inlet, the exhaust port, the synthesis liquid inlet, the solvent feeding port, and the discharge ports at the bottom of the preparation vessel, the bottom of the synthesis vessel, and the bottom of the refining vessel are all equipped with control valves.

7. The liquid lithium hexafluorophosphate synthesis apparatus according to claim 6, characterized in that: The control valve of the phosphorus pentafluoride inlet is equipped with an electric valve positioner.

8. The liquid lithium hexafluorophosphate synthesis apparatus according to claim 1, characterized in that: The synthesis reactor is equipped with a cooling water jacket and corresponding cooling water inlet and outlet, and the reactor body is covered with heat insulation material.

9. The liquid lithium hexafluorophosphate synthesis apparatus according to claim 1, characterized in that: The observation port is equipped with explosion-proof glass.

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