Production device and method of lithium bis (trifluorosulfonyl) imide

Abstract

The invention is applicable to the technical field of lithium ion batteries, and provides a production device and method of lithium bis (trifluorosulfonyl) imide, and the device comprises a raw material buffer tank, a feeding bin, a neutralization kettle, a phase splitting kettle, a dehydration reaction kettle, a three-in-one treatment kettle, a neutralization condenser, a tail gas condenser and a secondary filter, the method mainly comprises a synthesis section, a dehydration section and a product refining section. The equipment is simple in structure, low in investment, convenient to operate and beneficial to industrial popularization; the adopted process is simple and efficient, and isopropyl ether and dichloromethane can be recycled; all impurities generated in the production process are gas and are convenient to separate, so that the obtained lithium bis (trifluorosulfonyl) imide is high in purity.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a production device and method for lithium bis(trifluorosulfonyl)imide. Background Art

[0002] Lithium bis(trifluorosulfonyl)imide (LiTFSI for short) is a lithium salt with excellent electrochemical properties and thermal stability. As an important new lithium salt, LiTFSI can be used in lithium-ion batteries, but is currently mainly used in polymer solid-state batteries. It can also be applied to sulfide solid-state batteries and oxide solid-state batteries. Since LiTFSI has great application prospects in solid-state batteries, research on its process and production equipment is particularly important.

[0003] The existing production equipment of lithium bis(trifluorosulfonyl)imide has complicated reaction links, and the reaction impurities are not easy to remove, the solvent cannot be recycled, and the purity of the prepared lithium bis(trifluorosulfonyl)imide is poor. In addition, there are problems such as complex equipment structure and high investment, which is not conducive to industrial promotion.

[0004] Therefore, in view of the above situation, it is urgent to develop a production device for lithium bis(trifluorosulfonyl)imide to overcome the shortcomings in current practical applications. Summary of the invention

[0005] The object of the present invention is to provide a production device and method for lithium bis(trifluorosulfonyl)imide, aiming to solve the problems mentioned in the above background technology.

[0006] The present invention is implemented as follows: a production device for lithium bis(trifluorosulfonyl)imide, comprising a raw material buffer tank, a feeding bin, a neutralization kettle, a phase separation kettle, a dehydration reaction kettle, a three-in-one treatment kettle, a neutralization condenser, a tail gas condenser and a secondary filter, wherein the inlet of the neutralization kettle is connected to the outlet of the raw material buffer tank and the outlet of the lithium carbonate feeding bin, the inlet of the raw material buffer tank comprises a bis(trifluorosulfonyl)imide inlet and an isopropyl ether inlet, the neutralization kettle is further connected to a neutralization condenser, the neutralization kettle is used for a neutralization reaction of bis(trifluorosulfonyl)imide and lithium carbonate, and the neutralization condenser is used for a neutralization reaction of bis(trifluorosulfonyl)imide and lithium carbonate. The outlet of the kettle is connected to the inlet of the phase separation kettle through a secondary filter. The outlet of the phase separation kettle includes a water phase outlet and an oil phase outlet. The inlet of the dehydration reactor is connected to the water phase outlet and the dithionyl chloride inlet of the phase separation kettle. The dehydration reactor is also connected to a tail gas condenser. The dehydration reactor is used for converting dithionyl chloride and water into sulfur dioxide and hydrogen chloride gas by reaction. The inlet of the three-in-one treatment kettle is connected to the outlet of the dehydration reactor and the solvent inlet. The outlet of the three-in-one treatment kettle includes a dithionyl chloride crude product outlet, a solvent crude product outlet and a product outlet.

[0007] According to a further technical solution, the raw material buffer tank, neutralization kettle, phase separation kettle, dehydration reaction kettle and three-in-one treatment kettle are all provided with a stirrer and are equipped with a cooling half pipe or jacket.

[0008] According to a further technical solution, the secondary filter comprises a primary coarse filter and a secondary fine filter, and the outlet of the neutralization kettle is connected to the inlet of the phase separation kettle through the coarse filter and the fine filter in sequence; the coarse filter adopts a bag filter with a pore diameter of 2 to 10 μm; the pore diameter of the fine filter is 0.1 to 1 μm.

[0009] According to a further technical solution, the neutralization condenser is provided with a CO2 outlet, the tail gas condenser is provided with a tail gas outlet; and the three-in-one processing kettle is also provided with a vacuum interface.

[0010] According to a further technical solution, the oil phase outlet of the phase separation kettle is the organic phase outlet, an online conductivity monitoring system is provided at the water phase outlet, and the conductivity is interlocked with the cut-off valves of the oil phase outlet and the water phase outlet.

[0011] Another object of the present invention is to provide a method for producing lithium bis(trifluorosulfonyl)imide, comprising the following steps:

[0012] Step 1: Synthesis Section

[0013] First, the lithium carbonate in the feeding bin is added to the neutralization kettle by gravity flow; then the bistrifluorosulfonyl imide and isopropyl ether solution in the raw material buffer tank are added dropwise to the neutralization kettle; during the addition of the bistrifluorosulfonyl imide and isopropyl ether solution, the temperature of the material in the neutralization kettle is controlled to be 0-20°C, and the CO2 generated by the reaction is discharged to the tail gas absorption system through the neutralization condenser; after the bistrifluorosulfonyl imide and isopropyl ether solution are all added dropwise, hot water is passed through the half pipe or jacket of the neutralization kettle to gradually heat the material in the kettle to 30-50°C, and after no CO2 is generated in the system, the stirring reaction is continued for 1-5 hours; after the reaction is completed, the mixed material in the neutralization kettle is filtered through a secondary filter and transported to the phase separation kettle;

[0014] Step 2: Dehydration

[0015] 2.1 Oil-water separation

[0016] The mixed material from the neutralization kettle is placed in a phase separation kettle for 0.5 to 2 hours and then separated into layers; the upper layer is an organic phase, mainly isopropyl ether, which can be recycled after subsequent treatment; the lower layer is a salt water phase, which is transferred to a dehydration reactor;

[0017] 2.2 Dehydration reaction

[0018] First, add thionyl chloride to the dehydration reactor, then add the salt water phase from the phase separation kettle, and control the temperature of the materials in the dehydration reactor to be 0-20°C; the gas generated by the reaction is discharged to the tail gas absorption system through the tail gas condenser; after no gas is generated, gradually heat the materials in the dehydration reactor to 30-50°C, and continue to stir and react for 1-5 hours; after the reaction is completed, the mixed materials in the dehydration reactor are transported to the three-in-one treatment kettle;

[0019] Step 3: Product refining section

[0020] 3.1 Filtering

[0021] In the three-in-one treatment kettle, the mixed material from the dehydration reactor is first filtered, and the filtrate is a crude product of thionyl chloride, which can be recycled after being collected and treated;

[0022] 3.2 Washing

[0023] Add an appropriate amount of solvent to the filtered lithium bis(trifluorosulfonyl)imide, control the washing temperature at 0-30°C, and the washing stirring time at 0.5-2h; after the cleaning liquid is filtered through the three-in-one treatment kettle, it is transported to the subsequent section for collection and treatment, and can be recycled;

[0024] 3.3 Drying

[0025] After washing, the material in the three-in-one processing kettle is vacuumed, and the pressure in the kettle is reduced to below 500Pa. Then, hot water is introduced into the jacket or half pipe of the three-in-one processing kettle to raise the temperature in the kettle to 40-50°C, and dried for 2-6 hours. After drying, nitrogen is introduced into the three-in-one processing kettle to break the vacuum, and after the material in the kettle cools to room temperature, the product lithium bis(trifluorosulfonyl)imide is transported to the filling room for packaging.

[0026] A further technical solution is that in step 1, the mass ratio of bistrifluorosulfonyl imide to isopropyl ether is 1:1.1-5; the mass of the lithium carbonate is 13%-18% of the mass of bistrifluorosulfonyl imide; the temperature of the material after condensation in the neutralization condenser is 10-30°C, wherein the liquid phase material is returned to the neutralization kettle, and the CO2 gas is directly discharged to the tail gas absorption system.

[0027] A further technical solution is that in step 2.1, the interface between the water layer and the oil layer is determined by the online conductivity monitoring system at the outlet of the water phase; the water phase has a high conductivity of about 100-500s / m due to the presence of a large amount of lithium bis(trifluorosulfonyl)imide, while the conductivity of the oil phase is only 10-50ms / m. Therefore, during the oil-water separation process, the conductivity of the water phase outlet of the mixed material is monitored online, and the conductivity is interlocked with the oil-water shut-off valve. After the oil and water phases are separated, the water phase is first discharged from the bottom of the phase separation kettle and transported to the dehydration reactor. When the conductivity of the water phase outlet of the phase separation kettle is lower than 100ms / m, the system automatically closes the water phase shut-off valve of the phase separation kettle, and opens the oil phase shut-off valve of the phase separation kettle at the same time, and transports the oil phase material to the subsequent section for recycling.

[0028] A further technical solution is that in step 2.2, the mass of the added thionyl chloride is 25% to 70% of the mass of the bistrifluorosulfonyl imide feed; the temperature of the material after condensation in the tail gas condenser is 10 to 30°C, wherein the liquid phase material is returned to the dehydration reactor, and the HCl and SO2 mixed gas is directly discharged to the tail gas absorption system.

[0029] A further technical solution is that in step 3.2, the solvent is dichloromethane, and the mass of dichloromethane added is 15% to 80% of the mass of the bistrifluorosulfonyl imide feed; the washing is performed 3 to 5 times; in step 3.3, the purity of the obtained bistrifluorosulfonyl imide lithium is greater than 99.9%, and the water content is less than 40 ppm.

[0030] The present invention provides a production device and method for lithium bis(trifluorosulfonyl)imide, which has the following beneficial effects:

[0031] 1) The equipment has a simple structure, low investment, and is easy to operate, which is conducive to industrial promotion;

[0032] 2) The adopted process is simple and efficient, and can realize the recycling of isopropyl ether and dichloromethane;

[0033] 3) All impurities generated during the production process are gases, which are easy to separate, so the obtained lithium bis(trifluorosulfonyl)imide has high purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the structure of a production device for lithium bis(trifluorosulfonyl)imide provided in an embodiment of the present invention.

[0035] In the figure: 1. Raw material buffer tank; 2. Feeding bin; 3. Neutralization kettle; 4. Phase separation kettle; 5. Dehydration reactor; 6. Three-in-one treatment kettle; 7. Neutralization condenser; 8. Tail gas condenser; 9. Coarse filter; 10. Fine filter.

[0036] 11. Bistrifluorosulfonyl imide inlet; 12. Isopropyl ether inlet; 13. Thionyl chloride inlet; 14. Solvent inlet; 15. CO2 outlet; 16. Tail gas outlet; 17. Vacuum interface; 18. Organic phase outlet; 19. Thionyl chloride crude product outlet; 20. Solvent crude product outlet; 21. Product outlet. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0039] Example 1

[0040] like Figure 1 As shown, a production device for lithium bis(trifluorosulfonyl)imide provided by an embodiment of the present invention is suitable for producing lithium bis(trifluorosulfonyl)imide with bis(trifluorosulfonyl)imide as the main raw material, comprising a raw material buffer tank 1, a feeding bin 2, a neutralization kettle 3, a phase separation kettle 4, a dehydration reaction kettle 5, a three-in-one treatment kettle 6, a neutralization condenser 7, a tail gas condenser 8 and a secondary filter, wherein the inlet of the neutralization kettle 3 is connected to the outlet of the raw material buffer tank 1 and the outlet of the lithium carbonate feeding bin 2, the inlet of the raw material buffer tank 1 includes a bis(trifluorosulfonyl)imide inlet 11 and an isopropyl ether inlet 12, the neutralization kettle 3 is also connected to a neutralization condenser 7, and the neutralization kettle 3 is used for bis(trifluorosulfonyl)imide. and lithium carbonate for neutralization reaction, the outlet of the neutralization kettle 3 is connected to the inlet of the phase separation kettle 4 through a secondary filter, the outlet of the phase separation kettle 4 includes a water phase outlet and an oil phase outlet, the inlet of the dehydration reactor 5 is connected to the water phase outlet of the phase separation kettle 4 and the dithionyl chloride inlet 13, the dehydration reactor 5 is also connected to a tail gas condenser 8, the dehydration reactor 5 is used for the reaction of dithionyl chloride and water to convert sulfur dioxide and hydrogen chloride gas, the inlet of the three-in-one treatment kettle 6 is connected to the outlet of the dehydration reactor 5 and the solvent inlet 14, the outlet of the three-in-one treatment kettle 6 includes a dithionyl chloride crude product outlet 19, a solvent crude product outlet 20 and a product outlet 21.

[0041] As a preferred embodiment of the present invention, the raw material buffer tank 1, the neutralization kettle 3, the phase separation kettle 4, the dehydration reaction kettle 5 and the three-in-one treatment kettle 6 are all provided with a stirrer and are equipped with a cooling half pipe or jacket.

[0042] As a preferred embodiment of the present invention, the secondary filter includes a primary coarse filter 9 and a secondary fine filter 10, and the outlet of the neutralization kettle 3 is connected to the inlet of the phase separation kettle 4 through the coarse filter 9 and the fine filter 10 in sequence; the coarse filter 9 preferably adopts a bag filter with a pore diameter of 2 to 10 μm; the pore diameter of the fine filter 10 is 0.1 to 1 μm.

[0043] As a preferred embodiment of the present invention, the neutralization condenser 7 is provided with a CO 2 outlet 15 , and the tail gas condenser 8 is provided with a tail gas outlet 16 .

[0044] As a preferred embodiment of the present invention, the three-in-one processing kettle 6 is further provided with a vacuum interface 17 .

[0045] As a preferred embodiment of the present invention, the oil phase outlet of the phase separation kettle 4 is the organic phase outlet 18, and an online conductivity monitoring system is provided at the water phase outlet, and the conductivity is interlocked with the shut-off valves of the oil phase outlet and the water phase outlet.

[0046] like Figure 1 As shown, one embodiment of the present invention also provides a method for producing lithium bis(trifluorosulfonyl)imide, which is suitable for producing lithium bis(trifluorosulfonyl)imide using bis(trifluorosulfonyl)imide as the main raw material, and mainly includes a synthesis section, a dehydration section and a product refining section, including the following steps:

[0047] Step 1: Synthesis Section

[0048] First, the lithium carbonate in the feeding bin 2 is added to the neutralization kettle 3 by gravity flow; then the bistrifluorosulfonyl imide and isopropyl ether solution in the raw material buffer tank 1 are added dropwise to the neutralization kettle 3; during the addition of the bistrifluorosulfonyl imide and isopropyl ether solution, the temperature of the material in the neutralization kettle 3 is controlled to be 0°C, and the CO2 generated by the reaction is discharged to the tail gas absorption system through the neutralization condenser 7; after the bistrifluorosulfonyl imide and isopropyl ether solution are all added dropwise, hot water is passed into the half pipe or jacket of the neutralization kettle 3 to gradually heat the material in the kettle to 30°C, and after no CO2 is generated in the system, the stirring reaction is continued for 1 hour; after the reaction is completed, the mixed material in the neutralization kettle 3 is filtered through a secondary filter and transported to the phase separation kettle 4.

[0049] Among them, the mass ratio of bistrifluorosulfonyl imide and isopropyl ether is 1:1.1; the mass of the lithium carbonate is 13% of the mass of bistrifluorosulfonyl imide; the temperature of the material after condensation in the neutralization condenser 7 is 10°C, wherein the liquid phase material returns to the neutralization kettle 3, and the CO2 gas is directly discharged to the tail gas absorption system.

[0050] Step 2: Dehydration

[0051] 2.1 Oil-water separation

[0052] The mixed material from the neutralization kettle 3 is placed in the phase separation kettle 4 for 0.5 hours and then separated into layers; the upper layer is the organic phase, which is mainly isopropyl ether and can be recycled after subsequent treatment; the lower layer is the salt water phase, which is transferred to the dehydration reactor 5;

[0053] The interface between the water layer and the oil layer can be determined by the online conductivity monitoring system of the water phase outlet; the water phase has a high conductivity of about 100-500s / m due to the presence of a large amount of lithium bis(trifluorosulfonyl)imide, while the oil phase conductivity is only 10-50ms / m. Therefore, during the oil-water separation process, the conductivity of the water phase outlet of the mixed material is monitored online, and the conductivity is linked to the oil-water shut-off valve. After the oil and water phases are separated, the water phase is first discharged from the bottom of the phase separation kettle 4 and transported to the dehydration reactor 5. When the conductivity of the water phase outlet of the phase separation kettle 4 is lower than 100ms / m, the system automatically closes the water phase shut-off valve of the phase separation kettle 4, and opens the oil phase shut-off valve of the phase separation kettle 4 at the same time, and transports the oil phase material to the subsequent section for recycling.

[0054] 2.2 Dehydration reaction

[0055] First, add thionyl chloride to the dehydration reactor 5, then add the salt water phase from the phase separation reactor 4, and control the temperature of the material in the dehydration reactor 5 to be 0°C; the gas generated by the reaction is discharged to the tail gas absorption system through the tail gas condenser 8; after no gas is generated, gradually heat the material in the dehydration reactor 5 to 30°C, and continue to stir and react for 1 hour; after the reaction is completed, the mixed material in the dehydration reactor 5 is transported to the three-in-one treatment reactor 6.

[0056] The mass of thionyl chloride added is 25% of the mass of bistrifluorosulfonyl imide feed; the temperature of the material after condensation in the tail gas condenser 8 is 10°C, wherein the liquid phase material returns to the dehydration reactor 5, and the HCl and SO2 mixed gas is directly discharged to the tail gas absorption system.

[0057] Step 3: Product refining section (mainly including three processes: filtration, washing and drying)

[0058] 3.1 Filtering

[0059] In the three-in-one treatment kettle 6, the mixed material from the dehydration reaction kettle 5 is first filtered, and the filtrate is a crude product of thionyl chloride, which can be recycled after being collected and processed;

[0060] 3.2 Washing

[0061] Add an appropriate amount of solvent to the filtered lithium bis(trifluorosulfonyl)imide, control the washing temperature at 0°C, and stir the washing for 0.5h; the cleaning liquid is filtered through the three-in-one treatment kettle 6, and then transported to the subsequent section for collection and treatment, and can be recycled.

[0062] The solvent is dichloromethane, and the mass of the added dichloromethane is 15% of the mass of the bistrifluorosulfonimide feed; and the washing is performed in 3 to 5 times.

[0063] 3.3 Drying

[0064] After washing, the material in the three-in-one processing kettle 6 is vacuumed, and the pressure in the kettle is reduced to 500Pa. Then, hot water is introduced into the jacket or half pipe of the three-in-one processing kettle 6 to raise the temperature in the kettle to 40°C, and dried for 2 hours. After drying, nitrogen is introduced into the three-in-one processing kettle 6 to break the vacuum, and after the material in the kettle cools to room temperature, the product lithium bis(trifluorosulfonyl)imide is transported to the filling room for packaging.

[0065] The purity of the obtained lithium bis(trifluorosulfonyl)imide was 99.92%, and the water content was 21 ppm.

[0066] Example 2

[0067] like Figure 1 As shown, a production device for lithium bis(trifluorosulfonyl)imide provided by an embodiment of the present invention is suitable for producing lithium bis(trifluorosulfonyl)imide with bis(trifluorosulfonyl)imide as the main raw material, comprising a raw material buffer tank 1, a feeding bin 2, a neutralization kettle 3, a phase separation kettle 4, a dehydration reaction kettle 5, a three-in-one treatment kettle 6, a neutralization condenser 7, a tail gas condenser 8 and a secondary filter, wherein the inlet of the neutralization kettle 3 is connected to the outlet of the raw material buffer tank 1 and the outlet of the lithium carbonate feeding bin 2, the inlet of the raw material buffer tank 1 includes a bis(trifluorosulfonyl)imide inlet 11 and an isopropyl ether inlet 12, the neutralization kettle 3 is also connected to a neutralization condenser 7, and the neutralization kettle 3 is used for bis(trifluorosulfonyl)imide. and lithium carbonate for neutralization reaction, the outlet of the neutralization kettle 3 is connected to the inlet of the phase separation kettle 4 through a secondary filter, the outlet of the phase separation kettle 4 includes a water phase outlet and an oil phase outlet, the inlet of the dehydration reactor 5 is connected to the water phase outlet of the phase separation kettle 4 and the dithionyl chloride inlet 13, the dehydration reactor 5 is also connected to a tail gas condenser 8, the dehydration reactor 5 is used for the reaction of dithionyl chloride and water to convert sulfur dioxide and hydrogen chloride gas, the inlet of the three-in-one treatment kettle 6 is connected to the outlet of the dehydration reactor 5 and the solvent inlet 14, the outlet of the three-in-one treatment kettle 6 includes a dithionyl chloride crude product outlet 19, a solvent crude product outlet 20 and a product outlet 21.

[0068] As a preferred embodiment of the present invention, the raw material buffer tank 1, the neutralization kettle 3, the phase separation kettle 4, the dehydration reaction kettle 5 and the three-in-one treatment kettle 6 are all provided with a stirrer and are equipped with a cooling half pipe or jacket.

[0069] As a preferred embodiment of the present invention, the secondary filter includes a primary coarse filter 9 and a secondary fine filter 10, and the outlet of the neutralization kettle 3 is connected to the inlet of the phase separation kettle 4 through the coarse filter 9 and the fine filter 10 in sequence; the coarse filter 9 preferably adopts a bag filter with a pore diameter of 2μm; the pore diameter of the fine filter 10 is 0.1μm.

[0070] As a preferred embodiment of the present invention, the neutralization condenser 7 is provided with a CO 2 outlet 15 , and the tail gas condenser 8 is provided with a tail gas outlet 16 .

[0071] As a preferred embodiment of the present invention, the three-in-one processing kettle 6 is further provided with a vacuum interface 17 .

[0072] As a preferred embodiment of the present invention, the oil phase outlet of the phase separation kettle 4 is the organic phase outlet 18, and an online conductivity monitoring system is provided at the water phase outlet, and the conductivity is interlocked with the shut-off valves of the oil phase outlet and the water phase outlet.

[0073] like Figure 1 As shown, one embodiment of the present invention also provides a method for producing lithium bis(trifluorosulfonyl)imide, which is suitable for producing lithium bis(trifluorosulfonyl)imide using bis(trifluorosulfonyl)imide as the main raw material, and mainly includes a synthesis section, a dehydration section and a product refining section, including the following steps:

[0074] Step 1: Synthesis Section

[0075] First, the lithium carbonate in the feeding bin 2 is added to the neutralization kettle 3 by gravity flow; then the bistrifluorosulfonyl imide and isopropyl ether solution in the raw material buffer tank 1 are added dropwise to the neutralization kettle 3; during the addition of the bistrifluorosulfonyl imide and isopropyl ether solution, the temperature of the material in the neutralization kettle 3 is controlled to be 10°C, and the CO2 generated by the reaction is discharged to the tail gas absorption system through the neutralization condenser 7; after the bistrifluorosulfonyl imide and isopropyl ether solution are all added dropwise, hot water is passed into the half pipe or jacket of the neutralization kettle 3 to gradually heat the material in the kettle to 40°C, and after no CO2 is generated in the system, the stirring reaction is continued for 3 hours; after the reaction is completed, the mixed material in the neutralization kettle 3 is filtered through a secondary filter and transported to the phase separation kettle 4.

[0076] Among them, the mass ratio of bistrifluorosulfonyl imide and isopropyl ether is 1:3; the mass of the lithium carbonate is 15% of the mass of bistrifluorosulfonyl imide; the temperature of the material after condensation in the neutralization condenser 7 is 20°C, wherein the liquid phase material returns to the neutralization kettle 3, and the CO2 gas is directly discharged to the tail gas absorption system.

[0077] Step 2: Dehydration

[0078] 2.1 Oil-water separation

[0079] The mixed material from the neutralization kettle 3 is placed in the phase separation kettle 4 for 1 hour and then separated into layers; the upper layer is the organic phase, which is mainly isopropyl ether and can be recycled after subsequent treatment; the lower layer is the salt water phase, which is transferred to the dehydration reactor 5;

[0080] The interface between the water layer and the oil layer can be determined by the online conductivity monitoring system of the water phase outlet; the water phase has a high conductivity of about 100-500s / m due to the presence of a large amount of lithium bis(trifluorosulfonyl)imide, while the oil phase conductivity is only 10-50ms / m. Therefore, during the oil-water separation process, the conductivity of the water phase outlet of the mixed material is monitored online, and the conductivity is linked to the oil-water shut-off valve. After the oil and water phases are separated, the water phase is first discharged from the bottom of the phase separation kettle 4 and transported to the dehydration reactor 5. When the conductivity of the water phase outlet of the phase separation kettle 4 is lower than 100ms / m, the system automatically closes the water phase shut-off valve of the phase separation kettle 4, and opens the oil phase shut-off valve of the phase separation kettle 4 at the same time, and transports the oil phase material to the subsequent section for recycling.

[0081] 2.2 Dehydration reaction

[0082] First, add thionyl chloride to the dehydration reactor 5, then add the salt water phase from the phase separation reactor 4, and control the temperature of the material in the dehydration reactor 5 to be 10°C; the gas generated by the reaction is discharged to the tail gas absorption system through the tail gas condenser 8; after no gas is generated, gradually heat the material in the dehydration reactor 5 to 40°C, and continue to stir and react for 3 hours; after the reaction is completed, the mixed material in the dehydration reactor 5 is transported to the three-in-one treatment reactor 6.

[0083] The mass of thionyl chloride added is 50% of the mass of bistrifluorosulfonyl imide feed; the temperature of the material after condensation in the tail gas condenser 8 is 20°C, wherein the liquid phase material returns to the dehydration reactor 5, and the HCl and SO2 mixed gas is directly discharged to the tail gas absorption system.

[0084] Step 3: Product refining section (mainly including three processes: filtration, washing and drying)

[0085] 3.1 Filtering

[0086] In the three-in-one treatment kettle 6, the mixed material from the dehydration reaction kettle 5 is first filtered, and the filtrate is a crude product of thionyl chloride, which can be recycled after being collected and processed;

[0087] 3.2 Washing

[0088] Add an appropriate amount of solvent to the filtered lithium bis(trifluorosulfonyl)imide, control the washing temperature at 10°C, and stir the washing for 1 hour; the cleaning liquid is filtered through the three-in-one treatment kettle 6, and then transported to the subsequent section for collection and treatment, and can be recycled.

[0089] The solvent is dichloromethane, and the mass of the added dichloromethane is 50% of the mass of the bistrifluorosulfonimide feed; and the washing is performed in 3 to 5 times.

[0090] 3.3 Drying

[0091] After washing, the material in the three-in-one processing kettle 6 is vacuumed, and the pressure in the kettle is reduced to 300Pa. Then, hot water is introduced into the jacket or half pipe of the three-in-one processing kettle 6 to raise the temperature in the kettle to 45°C, and dried for 4 hours. After drying, nitrogen is introduced into the three-in-one processing kettle 6 to break the vacuum, and after the material in the kettle cools to room temperature, the product lithium bis(trifluorosulfonyl)imide is transported to the filling room for packaging.

[0092] The purity of the obtained lithium bistrifluorosulfonyl imide was 99.96%, and the water content was 14 ppm.

[0093] Example 3

[0094] like Figure 1 As shown, a production device for lithium bis(trifluorosulfonyl)imide provided by an embodiment of the present invention is suitable for producing lithium bis(trifluorosulfonyl)imide with bis(trifluorosulfonyl)imide as the main raw material, comprising a raw material buffer tank 1, a feeding bin 2, a neutralization kettle 3, a phase separation kettle 4, a dehydration reaction kettle 5, a three-in-one treatment kettle 6, a neutralization condenser 7, a tail gas condenser 8 and a secondary filter, wherein the inlet of the neutralization kettle 3 is connected to the outlet of the raw material buffer tank 1 and the outlet of the lithium carbonate feeding bin 2, the inlet of the raw material buffer tank 1 includes a bis(trifluorosulfonyl)imide inlet 11 and an isopropyl ether inlet 12, the neutralization kettle 3 is also connected to a neutralization condenser 7, and the neutralization kettle 3 is used for bis(trifluorosulfonyl)imide. and lithium carbonate for neutralization reaction, the outlet of the neutralization kettle 3 is connected to the inlet of the phase separation kettle 4 through a secondary filter, the outlet of the phase separation kettle 4 includes a water phase outlet and an oil phase outlet, the inlet of the dehydration reactor 5 is connected to the water phase outlet of the phase separation kettle 4 and the dithionyl chloride inlet 13, the dehydration reactor 5 is also connected to a tail gas condenser 8, the dehydration reactor 5 is used for the reaction of dithionyl chloride and water to convert sulfur dioxide and hydrogen chloride gas, the inlet of the three-in-one treatment kettle 6 is connected to the outlet of the dehydration reactor 5 and the solvent inlet 14, the outlet of the three-in-one treatment kettle 6 includes a dithionyl chloride crude product outlet 19, a solvent crude product outlet 20 and a product outlet 21.

[0095] As a preferred embodiment of the present invention, the raw material buffer tank 1, the neutralization kettle 3, the phase separation kettle 4, the dehydration reaction kettle 5 and the three-in-one treatment kettle 6 are all provided with a stirrer and are equipped with a cooling half pipe or jacket.

[0096] As a preferred embodiment of the present invention, the secondary filter includes a primary coarse filter 9 and a secondary fine filter 10, and the outlet of the neutralization kettle 3 is connected to the inlet of the phase separation kettle 4 through the coarse filter 9 and the fine filter 10 in sequence; the coarse filter 9 preferably adopts a bag filter with a pore diameter of 5μm; the pore diameter of the fine filter 10 is 0.5μm.

[0097] As a preferred embodiment of the present invention, the neutralization condenser 7 is provided with a CO 2 outlet 15 , and the tail gas condenser 8 is provided with a tail gas outlet 16 .

[0098] As a preferred embodiment of the present invention, the three-in-one processing kettle 6 is further provided with a vacuum interface 17 .

[0099] As a preferred embodiment of the present invention, the oil phase outlet of the phase separation kettle 4 is the organic phase outlet 18, and an online conductivity monitoring system is provided at the water phase outlet, and the conductivity is interlocked with the shut-off valves of the oil phase outlet and the water phase outlet.

[0100] like Figure 1 As shown, one embodiment of the present invention also provides a method for producing lithium bis(trifluorosulfonyl)imide, which is suitable for producing lithium bis(trifluorosulfonyl)imide using bis(trifluorosulfonyl)imide as the main raw material, and mainly includes a synthesis section, a dehydration section and a product refining section, including the following steps:

[0101] Step 1: Synthesis Section

[0102] First, the lithium carbonate in the feeding bin 2 is added to the neutralization kettle 3 by gravity flow; then the bistrifluorosulfonyl imide and isopropyl ether solution in the raw material buffer tank 1 are added dropwise to the neutralization kettle 3; during the addition of the bistrifluorosulfonyl imide and isopropyl ether solution, the temperature of the material in the neutralization kettle 3 is controlled to be 20°C, and the CO2 generated by the reaction is discharged to the tail gas absorption system through the neutralization condenser 7; after the bistrifluorosulfonyl imide and isopropyl ether solution are all added dropwise, hot water is passed into the half pipe or jacket of the neutralization kettle 3 to gradually heat the material in the kettle to 50°C, and after no CO2 is generated in the system, the stirring reaction is continued for 5 hours; after the reaction is completed, the mixed material in the neutralization kettle 3 is filtered through a secondary filter and transported to the phase separation kettle 4.

[0103] Among them, the mass ratio of bistrifluorosulfonyl imide and isopropyl ether is 1:5; the mass of the lithium carbonate is 18% of the mass of bistrifluorosulfonyl imide; the temperature of the material after condensation in the neutralization condenser 7 is 30°C, wherein the liquid phase material returns to the neutralization kettle 3, and the CO2 gas is directly discharged to the tail gas absorption system.

[0104] Step 2: Dehydration

[0105] 2.1 Oil-water separation

[0106] The mixed material from the neutralization kettle 3 is placed in the phase separation kettle 4 for 2 hours and then separated into layers; the upper layer is the organic phase, which is mainly isopropyl ether and can be recycled after subsequent treatment; the lower layer is the salt water phase, which is transferred to the dehydration reactor 5;

[0107] The interface between the water layer and the oil layer can be determined by the online conductivity monitoring system of the water phase outlet; the water phase has a high conductivity of about 100-500s / m due to the presence of a large amount of lithium bis(trifluorosulfonyl)imide, while the oil phase conductivity is only 10-50ms / m. Therefore, during the oil-water separation process, the conductivity of the water phase outlet of the mixed material is monitored online, and the conductivity is linked to the oil-water shut-off valve. After the oil and water phases are separated, the water phase is first discharged from the bottom of the phase separation kettle 4 and transported to the dehydration reactor 5. When the conductivity of the water phase outlet of the phase separation kettle 4 is lower than 100ms / m, the system automatically closes the water phase shut-off valve of the phase separation kettle 4, and opens the oil phase shut-off valve of the phase separation kettle 4 at the same time, and transports the oil phase material to the subsequent section for recycling.

[0108] 2.2 Dehydration reaction

[0109] First, add thionyl chloride to the dehydration reactor 5, then add the salt water phase from the phase separation reactor 4, and control the temperature of the material in the dehydration reactor 5 to be 20°C; the gas generated by the reaction is discharged to the tail gas absorption system through the tail gas condenser 8; after no gas is generated, gradually heat the material in the dehydration reactor 5 to 50°C, and continue to stir and react for 5 hours; after the reaction is completed, the mixed material in the dehydration reactor 5 is transported to the three-in-one treatment reactor 6.

[0110] The added mass of thionyl chloride is 70% of the mass of bistrifluorosulfonyl imide; the temperature of the material after condensation in the tail gas condenser 8 is 30°C, wherein the liquid phase material returns to the dehydration reactor 5, and the HCl and SO2 mixed gas is directly discharged to the tail gas absorption system.

[0111] Step 3: Product refining section (mainly including three processes: filtration, washing and drying)

[0112] 3.1 Filtering

[0113] In the three-in-one treatment kettle 6, the mixed material from the dehydration reaction kettle 5 is first filtered, and the filtrate is a crude product of thionyl chloride, which can be recycled after being collected and processed;

[0114] 3.2 Washing

[0115] Add an appropriate amount of solvent to the filtered lithium bis(trifluorosulfonyl)imide, control the washing temperature at 30°C, and stir the washing for 2 hours; the cleaning liquid is filtered through the three-in-one treatment kettle 6, and then transported to the subsequent section for collection and treatment, and can be recycled.

[0116] The solvent is dichloromethane, and the added mass of dichloromethane is 80% of the added mass of bistrifluorosulfonimide; and the washing is performed in 5 times.

[0117] 3.3 Drying

[0118] After washing, the material in the three-in-one processing kettle 6 is vacuumed, and the pressure in the kettle is reduced to 200Pa. Then, hot water is introduced into the jacket or half pipe of the three-in-one processing kettle 6 to raise the temperature in the kettle to 50°C, and dried for 6 hours. After drying, nitrogen is introduced into the three-in-one processing kettle 6 to break the vacuum, and after the material in the kettle cools to room temperature, the product lithium bis(trifluorosulfonyl)imide is transported to the filling room for packaging.

[0119] The purity of the obtained lithium bistrifluorosulfonyl imide was 99.98%, and the water content was 4 ppm.

[0120] Example 4

[0121] like Figure 1 As shown, a production device for lithium bis(trifluorosulfonyl)imide provided by an embodiment of the present invention is suitable for producing lithium bis(trifluorosulfonyl)imide with bis(trifluorosulfonyl)imide as the main raw material, comprising a raw material buffer tank 1, a feeding bin 2, a neutralization kettle 3, a phase separation kettle 4, a dehydration reaction kettle 5, a three-in-one treatment kettle 6, a neutralization condenser 7, a tail gas condenser 8 and a secondary filter, wherein the inlet of the neutralization kettle 3 is connected to the outlet of the raw material buffer tank 1 and the outlet of the lithium carbonate feeding bin 2, the inlet of the raw material buffer tank 1 includes a bis(trifluorosulfonyl)imide inlet 11 and an isopropyl ether inlet 12, the neutralization kettle 3 is also connected to a neutralization condenser 7, and the neutralization kettle 3 is used for bis(trifluorosulfonyl)imide. and lithium carbonate for neutralization reaction, the outlet of the neutralization kettle 3 is connected to the inlet of the phase separation kettle 4 through a secondary filter, the outlet of the phase separation kettle 4 includes a water phase outlet and an oil phase outlet, the inlet of the dehydration reactor 5 is connected to the water phase outlet of the phase separation kettle 4 and the dithionyl chloride inlet 13, the dehydration reactor 5 is also connected to a tail gas condenser 8, the dehydration reactor 5 is used for the reaction of dithionyl chloride and water to convert sulfur dioxide and hydrogen chloride gas, the inlet of the three-in-one treatment kettle 6 is connected to the outlet of the dehydration reactor 5 and the solvent inlet 14, the outlet of the three-in-one treatment kettle 6 includes a dithionyl chloride crude product outlet 19, a solvent crude product outlet 20 and a product outlet 21.

[0122] As a preferred embodiment of the present invention, the raw material buffer tank 1, the neutralization kettle 3, the phase separation kettle 4, the dehydration reaction kettle 5 and the three-in-one treatment kettle 6 are all provided with a stirrer and are equipped with a cooling half pipe or jacket.

[0123] As a preferred embodiment of the present invention, the secondary filter includes a primary coarse filter 9 and a secondary fine filter 10, and the outlet of the neutralization kettle 3 is connected to the inlet of the phase separation kettle 4 through the coarse filter 9 and the fine filter 10 in sequence; the coarse filter 9 preferably adopts a bag filter with a pore diameter of 10μm; the pore diameter of the fine filter 10 is 1μm.

[0124] As a preferred embodiment of the present invention, the neutralization condenser 7 is provided with a CO 2 outlet 15 , and the tail gas condenser 8 is provided with a tail gas outlet 16 .

[0125] As a preferred embodiment of the present invention, the three-in-one processing kettle 6 is further provided with a vacuum interface 17 .

[0126] As a preferred embodiment of the present invention, the oil phase outlet of the phase separation kettle 4 is the organic phase outlet 18, and an online conductivity monitoring system is provided at the water phase outlet, and the conductivity is interlocked with the shut-off valves of the oil phase outlet and the water phase outlet.

[0127] like Figure 1 As shown, one embodiment of the present invention also provides a method for producing lithium bis(trifluorosulfonyl)imide, which is suitable for producing lithium bis(trifluorosulfonyl)imide using bis(trifluorosulfonyl)imide as the main raw material, and mainly includes a synthesis section, a dehydration section and a product refining section, including the following steps:

[0128] Step 1: Synthesis Section

[0129] First, the lithium carbonate in the feeding bin 2 is added to the neutralization kettle 3 by gravity flow; then the bistrifluorosulfonyl imide and isopropyl ether solution in the raw material buffer tank 1 are added dropwise to the neutralization kettle 3; during the addition of the bistrifluorosulfonyl imide and isopropyl ether solution, the temperature of the material in the neutralization kettle 3 is controlled to be 15°C, and the CO2 generated by the reaction is discharged to the tail gas absorption system through the neutralization condenser 7; after the bistrifluorosulfonyl imide and isopropyl ether solution are all added dropwise, hot water is passed into the half pipe or jacket of the neutralization kettle 3 to gradually heat the material in the kettle to 35°C, and after no CO2 is generated in the system, the stirring reaction is continued for 4 hours; after the reaction is completed, the mixed material in the neutralization kettle 3 is filtered through a secondary filter and transported to the phase separation kettle 4.

[0130] Among them, the mass ratio of bistrifluorosulfonyl imide and isopropyl ether is 1:2; the mass of the lithium carbonate is 16% of the mass of bistrifluorosulfonyl imide; the temperature of the material after condensation in the neutralization condenser 7 is 15°C, wherein the liquid phase material returns to the neutralization kettle 3, and the CO2 gas is directly discharged to the tail gas absorption system.

[0131] Step 2: Dehydration

[0132] 2.1 Oil-water separation

[0133] The mixed material from the neutralization kettle 3 is placed in the phase separation kettle 4 for 1 hour and then separated into layers; the upper layer is the organic phase, which is mainly isopropyl ether and can be recycled after subsequent treatment; the lower layer is the salt water phase, which is transferred to the dehydration reactor 5;

[0134] The interface between the water layer and the oil layer can be determined by the online conductivity monitoring system of the water phase outlet; the water phase has a high conductivity of about 100-500s / m due to the presence of a large amount of lithium bis(trifluorosulfonyl)imide, while the oil phase conductivity is only 10-50ms / m. Therefore, during the oil-water separation process, the conductivity of the water phase outlet of the mixed material is monitored online, and the conductivity is linked to the oil-water shut-off valve. After the oil and water phases are separated, the water phase is first discharged from the bottom of the phase separation kettle 4 and transported to the dehydration reactor 5. When the conductivity of the water phase outlet of the phase separation kettle 4 is lower than 100ms / m, the system automatically closes the water phase shut-off valve of the phase separation kettle 4, and opens the oil phase shut-off valve of the phase separation kettle 4 at the same time, and transports the oil phase material to the subsequent section for recycling.

[0135] 2.2 Dehydration reaction

[0136] First, add thionyl chloride to the dehydration reactor 5, then add the salt water phase from the phase separation reactor 4, and control the temperature of the material in the dehydration reactor 5 to be 10°C; the gas generated by the reaction is discharged to the tail gas absorption system through the tail gas condenser 8; after no gas is generated, gradually heat the material in the dehydration reactor 5 to 40°C, and continue to stir and react for 4 hours; after the reaction is completed, the mixed material in the dehydration reactor 5 is transported to the three-in-one treatment reactor 6.

[0137] The mass of thionyl chloride added is 50% of the mass of bistrifluorosulfonyl imide feed; the temperature of the material after condensation in the tail gas condenser 8 is 15°C, wherein the liquid phase material returns to the dehydration reactor 5, and the HCl and SO2 mixed gas is directly discharged to the tail gas absorption system.

[0138] Step 3: Product refining section (mainly including three processes: filtration, washing and drying)

[0139] 3.1 Filtering

[0140] In the three-in-one treatment kettle 6, the mixed material from the dehydration reaction kettle 5 is first filtered, and the filtrate is a crude product of thionyl chloride, which can be recycled after being collected and processed;

[0141] 3.2 Washing

[0142] Add an appropriate amount of solvent to the filtered lithium bis(trifluorosulfonyl)imide, control the washing temperature at 20°C, and stir the washing for 1.5 hours; the cleaning liquid is filtered through the three-in-one treatment kettle 6, and then transported to the subsequent section for collection and treatment, and can be recycled.

[0143] The solvent is dichloromethane, and the mass of the added dichloromethane is 55% of the mass of the bistrifluorosulfonimide feed; and the washing is performed in 4 times.

[0144] 3.3 Drying

[0145] After washing, the material in the three-in-one processing kettle 6 is vacuumed, and the pressure in the kettle is reduced to 100Pa. Then, hot water is introduced into the jacket or half pipe of the three-in-one processing kettle 6 to raise the temperature in the kettle to 50°C, and dried for 5 hours. After drying, nitrogen is introduced into the three-in-one processing kettle 6 to break the vacuum, and after the material in the kettle cools to room temperature, the product lithium bis(trifluorosulfonyl)imide is transported to the filling room for packaging.

[0146] The purity of the obtained lithium bistrifluorosulfonyl imide was 99.95%, and the water content was 7 ppm.

[0147] The above embodiment of the present invention provides a production device and method for lithium bis(trifluorosulfonyl)imide, which mainly involves neutralization reaction and dehydration reaction, as follows:

[0148] Neutralization reaction:

[0149]

[0150] Dehydration reaction:

[0151] H,O+·SOC S02+2HCI;

[0152] Bistrifluorosulfonyl imide can be converted into lithium bistrifluorosulfonyl imide by neutralization reaction. In this reaction, carbon dioxide is easily removed as a gas, so the impurity is mainly water. By dehydration reaction, the water in the system can be converted into sulfur dioxide and hydrogen chloride gas without introducing other impurities, so high-purity lithium bistrifluorosulfonyl imide can be obtained.

[0153] The invention can realize the recycling of solvents, and at the same time, the equipment has a simple structure and low investment, which is conducive to industrial promotion.

[0154] In summary, the equipment of the present invention has a simple structure, low investment, and convenient operation, which is conducive to industrial promotion; the adopted process is simple and efficient, and can realize the recycling of isopropyl ether and dichloromethane; the impurities generated in the production process are all gases, which are easy to separate, so the obtained lithium bistrifluorosulfonyl imide has high purity.

[0155] The PLC controller disclosed in the prior art can be used to control each component. The model and circuit connection of each component are not specifically limited and can be flexibly set in actual application.

[0156] The circuits, electronic components and modules involved are all prior art and can be fully implemented by those skilled in the art. Needless to say, the content protected by the present invention does not involve improvements to software and methods.

[0157] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0158] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A production device for lithium bis(trifluorosulfonyl)imide, characterized in that: It comprises a raw material buffer tank (1), a feeding bin (2), a neutralization kettle (3), a phase separation kettle (4), a dehydration reaction kettle (5), a three-in-one treatment kettle (6), a neutralization condenser (7), a tail gas condenser (8) and a secondary filter; The inlet of the neutralization kettle (3) is connected to the outlet of the raw material buffer tank (1) and the outlet of the lithium carbonate feeding bin (2), the inlet of the raw material buffer tank (1) includes a bistrifluorosulfonyl imide inlet (11) and an isopropyl ether inlet (12), and the neutralization kettle (3) is also connected to a neutralization condenser (7), and the neutralization kettle (3) is used for a neutralization reaction between bistrifluorosulfonyl imide and lithium carbonate; The outlet of the neutralization kettle (3) is connected to the inlet of the phase separation kettle (4) through a secondary filter. The outlet of the phase separation kettle (4) includes a water phase outlet and an oil phase outlet. The inlet of the dehydration reaction kettle (5) is connected to the water phase outlet of the phase separation kettle (4) and the thionyl chloride inlet (13). The dehydration reaction kettle (5) is also connected to a tail gas condenser (8). The dehydration reaction kettle (5) is used to convert thionyl chloride and water into sulfur dioxide and hydrogen chloride gas by reaction. The inlet of the three-in-one treatment kettle (6) is connected to the outlet of the dehydration reaction kettle (5) and the solvent inlet (14), and the outlet of the three-in-one treatment kettle (6) includes a crude thionyl chloride outlet (19), a crude solvent outlet (20) and a product outlet (21).

2. The production device of lithium bis(trifluorosulfonyl)imide according to claim 1, characterized in that: The raw material buffer tank (1), the neutralization kettle (3), the phase separation kettle (4), the dehydration reaction kettle (5) and the three-in-one treatment kettle (6) are all equipped with a stirrer and are provided with a cooling half pipe or a jacket.

3. The production device of lithium bis(trifluorosulfonyl)imide according to claim 1 or 2, characterized in that: The secondary filter comprises a primary coarse filter (9) and a secondary fine filter (10), and the outlet of the neutralization kettle (3) is connected to the inlet of the phase separation kettle (4) via the coarse filter (9) and the fine filter (10) in sequence; The coarse filter (9) is a bag filter with a filter hole diameter of 2 to 10 μm; The filter pore diameter of the fine filter (10) is 0.1-1 μm.

4. The production device of lithium bis(trifluorosulfonyl)imide according to claim 1, characterized in that: The neutralization condenser (7) is provided with a CO2 outlet (15), and the tail gas condenser (8) is provided with a tail gas outlet (16); The three-in-one processing kettle (6) is also provided with a vacuum interface (17).

5. The production device of lithium bis(trifluorosulfonyl)imide according to claim 1, characterized in that: The oil phase outlet of the phase separation kettle (4) is the organic phase outlet (18), and an online conductivity monitoring system is provided at the water phase outlet, and the conductivity is interlocked with the cut-off valves of the oil phase outlet and the water phase outlet.

6. A method for producing lithium bis(trifluorosulfonyl)imide, characterized in that: The following steps are involved: Step 1: Synthesis Section First, the lithium carbonate in the feeding bin (2) is added to the neutralization kettle (3) by gravity flow; then the bistrifluorosulfonyl imide and isopropyl ether solution in the raw material buffer tank (1) are added dropwise to the neutralization kettle (3); during the addition of the bistrifluorosulfonyl imide and isopropyl ether solution, the temperature of the material in the neutralization kettle (3) is controlled to be 0-20°C, and the CO2 generated by the reaction is discharged to the tail gas absorption system through the neutralization condenser (7); after the bistrifluorosulfonyl imide and isopropyl ether solution are all added dropwise, hot water is introduced into the half pipe or jacket of the neutralization kettle (3) to gradually heat the material in the kettle to 30-50°C, and after no CO2 is generated in the system, the stirring reaction is continued for 1-5 hours; after the reaction is completed, the mixed material in the neutralization kettle (3) is filtered through a secondary filter and then transported to the phase separation kettle (4); Step 2: Dehydration Section 2.1 Oil-water separation The mixed material from the neutralization kettle (3) is placed in a phase separation kettle (4) for 0.5 to 2 hours and then separated into layers; The upper layer is an organic phase, mainly isopropyl ether, which can be recycled after treatment; the lower layer is a salt water phase, which is transferred to a dehydration reactor (5); 2.2 Dehydration reaction First, thionyl chloride is added to the dehydration reaction kettle (5), and then the salt-containing phase from the phase separation kettle (4) is added, and the temperature of the materials in the dehydration reaction kettle (5) is controlled to be 0-20° C.; the gas generated by the reaction is discharged to the tail gas absorption system through the tail gas condenser (8); after no gas is generated, the materials in the dehydration reaction kettle (5) are gradually heated to 30-50° C., and the stirring reaction is continued for 1-5 hours; after the reaction is completed, the mixed materials in the dehydration reaction kettle (5) are transported to the three-in-one treatment kettle (6); Step 3: Product refining section 3.1 Filtering In the three-in-one treatment kettle (6), the mixed material from the dehydration reaction kettle (5) is first filtered, and the filtrate is a crude product of dichlorothionyl, which can be recycled after being collected and treated; 3.2 Washing Adding an appropriate amount of solvent to the filtered lithium bis(trifluorosulfonyl)imide, controlling the washing temperature at 0-30°C, and the washing stirring time at 0.5-2h; filtering the washing liquid through a three-in-one treatment kettle (6), and then transporting it to a subsequent process section for collection and treatment, so that it can be recycled; 3.3 Drying After washing, the material in the three-in-one treatment kettle (6) is vacuumed to reduce the pressure in the kettle to below 500 Pa, and then hot water is introduced into the jacket or half pipe of the three-in-one treatment kettle (6) to raise the temperature in the kettle to 40-50° C., and then dried for 2-6 hours. After drying, nitrogen is introduced into the three-in-one treatment kettle (6) to break the vacuum, and after the material in the kettle cools to room temperature, the product lithium bis(trifluorosulfonyl)imide is transported to the filling room for packaging.

7. The method for producing lithium bis(trifluorosulfonyl)imide according to claim 6, characterized in that: In step 1, the mass ratio of bistrifluorosulfonimide to isopropyl ether is 1:1.1-5; The mass of the lithium carbonate is 13% to 18% of the mass of bistrifluorosulfonimide; The temperature of the material after condensation in the neutralization condenser (7) is 10-30°C, wherein the liquid phase material returns to the neutralization kettle (3), and the CO2 gas is directly discharged to the tail gas absorption system.

8. The method for producing lithium bis(trifluorosulfonyl)imide according to claim 6, characterized in that: In step 2.1, the interface between the water layer and the oil layer is determined by an online conductivity monitoring system at the water phase outlet; During the oil-water separation process, the conductivity of the water phase outlet of the mixed material is monitored online, and the conductivity is interlocked with the oil-water shut-off valve; After the oil and water phases are separated, the water phase is first discharged from the bottom of the phase separation kettle (4) and transported to the dehydration reactor (5); when the conductivity of the water phase outlet of the phase separation kettle (4) is lower than 100ms / m, the system automatically closes the water phase shut-off valve of the phase separation kettle (4) and opens the oil phase shut-off valve of the phase separation kettle (4) at the same time, and transports the oil phase material to the subsequent process section for recycling.

9. The method for producing lithium bis(trifluorosulfonyl)imide according to claim 7, characterized in that: In step 2.2, the mass of the added thionyl chloride is 25% to 70% of the mass of the bistrifluorosulfonyl imide feed; The temperature of the material after condensation in the tail gas condenser (8) is 10-30°C, wherein the liquid phase material is returned to the dehydration reactor (5), and the HCl and SO2 mixed gas is directly discharged to the tail gas absorption system.

10. The method for producing lithium bis(trifluorosulfonyl)imide according to claim 6, characterized in that: In step 3.2, the solvent is dichloromethane, and the mass of dichloromethane added is 15% to 80% of the mass of bistrifluorosulfonimide feed; and the washing is performed in 3 to 5 times.

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