A purification system for lithium bis(fluorosulfonyl)imide

Abstract

This invention provides a purification system for lithium bis(fluorosulfonyl)imide, comprising a dissolution module, a concentration module, and an evaporation and crystallization module. The dissolution module has an inlet and an outlet. The concentration module includes a reverse osmosis component, with the outlet of the dissolution module connected to the inlet of the reverse osmosis component. The inlet of the evaporation and crystallization module is connected to the outlet of the reverse osmosis component. The dissolution module dissolves crude lithium bis(fluorosulfonyl)imide in an organic solvent to form a mixed solution. The reverse osmosis component purifies and concentrates the mixed solution to obtain a concentrate and a permeate. The evaporation and crystallization module evaporates and crystallizes the concentrate obtained from the reverse osmosis component to obtain pure lithium bis(fluorosulfonyl)imide. This invention can efficiently remove impurities from lithium bis(fluorosulfonyl)imide, produce high-purity lithium bis(fluorosulfonyl)imide, increase the concentration of lithium bis(fluorosulfonyl)imide, and reduce production costs.

Description

Technical Field

[0001] This utility model relates to the field of preparation of lithium bisfluorosulfonylimide, and specifically to a purification system for lithium bisfluorosulfonylimide. Background Technology

[0002] Lithium bisfluorosulfonylimide (LiFSI) is a next-generation lithium salt for rechargeable lithium-ion batteries due to its excellent low-temperature performance, high voltage compatibility, superior thermal stability, and safety. It is often used in combination with lithium hexafluorophosphate as an electrolyte additive in rechargeable lithium batteries to improve battery capacity and electrochemical performance. Additionally, LiFSI has important industrial applications as a polymerization catalyst and an antistatic agent. The purity, moisture content, acidity, chloride ion content, and residual solvent content of the bisfluorosulfonylimide salt added to the electrolyte must meet specific technical requirements. The preparation of lithium bis(fluorosulfonyl)imide mainly involves three steps: chlorination, fluorination, and salt formation. These steps include the synthesis of bis(chlorosulfonyl)imide, the synthesis of bis(fluorosulfonyl)imide, and the synthesis of lithium bis(fluorosulfonyl)imide. The synthesis process involves many raw materials and equipment, and there is a lot of exothermic reaction. As a result, the lithium bis(fluorosulfonyl)imide synthesized in one step is a crude salt with high levels of water, acid, chloride ions, and residual solvent. It needs to be purified to obtain a salt that meets all the required standards.

[0003] Currently, high-purity lithium difluorosulfonylimide is often prepared by solution crystallization or a combination of synthesis and vacuum distillation and crystallization. However, these processes are complex and time-consuming, and they introduce organic solvents, which cause serious environmental pollution. The subsequent solvent recovery and treatment issues need to be considered, resulting in high costs and energy consumption.

[0004] Therefore, it is necessary to provide a new technical solution. Utility Model Content

[0005] To address the technical problems existing in the prior art, this utility model discloses a purification system for lithium bis(fluorosulfonyl)imide, which can efficiently remove impurities from lithium bis(fluorosulfonyl)imide, produce high-purity lithium bis(fluorosulfonyl)imide, increase the concentration of lithium bis(fluorosulfonyl)imide, and reduce production costs. The specific technical solution is as follows:

[0006] This invention provides a purification system for lithium bis(fluorosulfonyl)imide, which includes a dissolution module, a concentration module, and an evaporation and crystallization module.

[0007] The dissolving module has an inlet end and an outlet end.

[0008] The concentration module includes a reverse osmosis component, which has an inlet end and an outlet end. The outlet end of the dissolution module is connected to the inlet end of the reverse osmosis component.

[0009] The evaporation crystallization module has an inlet end and an outlet end, and the inlet end of the evaporation crystallization module is connected to the outlet end of the reverse osmosis component.

[0010] The crude lithium difluorosulfonylimide enters the dissolution module through the inlet end of the self-dissolution module. The dissolution module is configured to dissolve the crude lithium difluorosulfonylimide in an organic solvent to form a mixed solution. The reverse osmosis component is configured to purify and concentrate the mixed solution to obtain a concentrate and a permeate. The evaporation and crystallization module is configured to evaporate and crystallize the concentrate obtained by the reverse osmosis component to obtain pure lithium difluorosulfonylimide.

[0011] Furthermore, the concentration module also includes a first conveying device, which is disposed between the dissolution module and the reverse osmosis component. The outlet end of the dissolution module is connected to the inlet end of the first conveying device, and the outlet end of the first conveying device is connected to the inlet end of the reverse osmosis component.

[0012] The outlet end of the reverse osmosis component includes a first outlet end and a second outlet end of the reverse osmosis component, and the first outlet end of the reverse osmosis component is connected to the inlet end of the evaporation crystallization module.

[0013] Furthermore, it also includes a reuse module; the inlet end of the reuse module is connected to the second outlet end of the reverse osmosis component, and the outlet end of the reuse module is connected to the inlet end of the dissolution module. The reuse module is used to perform secondary reverse osmosis on the permeate obtained from the reverse osmosis component and to return the permeate obtained from the secondary reverse osmosis back to the dissolution module.

[0014] Furthermore, the reuse module includes a secondary reverse osmosis component, a reuse tank, and a reflux device. The inlet end of the secondary reverse osmosis component is connected to the outlet end of the reverse osmosis component, the first outlet end of the secondary reverse osmosis component is connected to the inlet end of the reuse tank, the outlet end of the reuse tank is connected to the inlet end of the reflux device, and the outlet end of the reflux device is connected to the inlet end of the dissolution module.

[0015] The secondary reverse osmosis module is used to purify the permeate obtained from the reverse osmosis module to obtain secondary reverse osmosis permeate and secondary reverse osmosis concentrate;

[0016] The recycling tank is used to store the secondary reverse osmosis permeate purified by the secondary reverse osmosis module. The reflux device is used to return the stored secondary reverse osmosis permeate to the dissolution module. The secondary reverse osmosis concentrate filtered by the secondary reverse osmosis module is discharged through the second outlet end of the secondary reverse osmosis module.

[0017] Furthermore, the reuse module also includes a storage tank; the inlet end of the storage tank is connected to the second outlet end of the reverse osmosis component, and the outlet end of the storage tank is connected to the inlet end of the secondary reverse osmosis component. The storage tank is used to store the permeate obtained by the concentration module.

[0018] Furthermore, the reuse module also includes a second conveying device; the second conveying device is disposed between the liquid storage tank and the secondary reverse osmosis component, the outlet end of the liquid storage tank is connected to the inlet end of the second conveying device, and the outlet end of the second conveying device is connected to the inlet end of the secondary reverse osmosis component.

[0019] Furthermore, the reflux device is a circulating pump, and both the first conveying device and the second conveying device are high-pressure pumps. This invention has the following beneficial effects:

[0020] (1) The purification system of lithium difluorosulfonylimide of this invention can efficiently remove impurities from lithium difluorosulfonylimide and produce high-purity lithium difluorosulfonylimide. On the other hand, the concentration system can concentrate the lithium difluorosulfonylimide solution to be purified, thereby increasing the concentration of the concentrated lithium difluorosulfonylimide and reducing the amount of organic solvent transported to the evaporation and crystallization module, thereby reducing the investment cost of the evaporation and crystallization module.

[0021] (2) The purification system of lithium bisfluorosulfonylimide of this utility model can realize the recycling and reuse of waste organic solvents by setting up a reuse module, which helps to protect the environment and reduce costs.

[0022] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a structural block diagram of the purification system for lithium bis(fluorosulfonyl)imide of this utility model.

[0025] Figure 2 This is a process flow diagram of the purification system for lithium bis(fluorosulfonyl)imide of this utility model.

[0026] Among them, 1-dissolving module, 2-concentration module, 3-reuse module, 4-evaporation and crystallization module, 21-first conveying device, 22-reverse osmosis component, 31-storage tank, 32-second conveying device, 33-secondary reverse osmosis component, 34-reuse tank, 35-reflux device. Detailed Implementation

[0027] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0028] In the description of this utility model, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0029] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0030] Please see Figure 1 and Figure 2 , Figure 1 This is a structural block diagram of the purification system for lithium bis(fluorosulfonyl)imide of this utility model. Figure 2 This is a process flow diagram of the purification system for lithium bis(fluorosulfonyl)imide of this utility model.

[0031] Please see Figure 1 and Figure 2 This invention provides a purification system for lithium bis(fluorosulfonyl)imide, which includes a dissolution module 1, a concentration module 2, and an evaporation and crystallization module 4.

[0032] The dissolving module 1 has an inlet end and an outlet end. Crude lithium difluorosulfonylimide enters the dissolving module 1 through the inlet end and is dissolved in the dissolving module 1 by an organic solvent to form a mixed solution of lithium difluorosulfonylimide.

[0033] The concentration module 2 includes a reverse osmosis component 22 and a first conveying device 21. The outlet of the reverse osmosis component includes a first outlet and a second outlet. The first conveying device 21 is disposed between the dissolution module 1 and the reverse osmosis component 22. The outlet of the dissolution module 1 is connected to the inlet of the first conveying device 21, and the outlet of the first conveying device 21 is connected to the inlet of the reverse osmosis component 22. The first outlet of the reverse osmosis component 22 is connected to the inlet of the evaporation and crystallization module 4. The first conveying device 21 is a high-pressure pump. The first conveying device 21 is used to convey the mixed solution formed in the dissolution module 1 to the reverse osmosis component 22. The reverse osmosis membrane of the reverse osmosis component 22 purifies and concentrates the mixed solution to obtain a concentrate and a permeate.

[0034] The inlet of the evaporation crystallization module is connected to the first outlet of the reverse osmosis component. The concentrate obtained by the reverse osmosis component 22 enters the evaporation crystallization module 4 from the inlet of the evaporation crystallization module through the first outlet of the reverse osmosis component. The evaporation crystallization module 4 performs evaporation crystallization treatment on the concentrate obtained by the reverse osmosis component 22 to obtain pure lithium difluorosulfonylimide.

[0035] Please continue reading. Figure 2 In one embodiment, the purification system further includes a reuse module 3. The reuse module 3 performs secondary reverse osmosis purification on the permeate obtained from the reverse osmosis component 22 to obtain a pure organic solvent, which can be reused in the dissolution module 1 to achieve resource utilization.

[0036] Specifically, the reuse module 3 includes a secondary reverse osmosis component 33, a reuse tank 34, and a reflux device 35. The inlet end of the secondary reverse osmosis component 33 is connected to the second outlet end of the reverse osmosis component 22, the first outlet end of the secondary reverse osmosis component 33 is connected to the inlet end of the reuse tank 34, the outlet end of the reuse tank 34 is connected to the inlet end of the reflux device 35, and the outlet end of the reflux device 35 is connected to the inlet end of the dissolution module 1. The secondary reverse osmosis component 33 is used to purify the permeate obtained from the reverse osmosis component 22 to obtain secondary reverse osmosis permeate and secondary reverse osmosis concentrate; the reuse tank 34 is used to store the secondary reverse osmosis permeate purified by the secondary reverse osmosis component; the reflux device 35 is used to return the stored secondary reverse osmosis permeate to the dissolution module 1; and the secondary reverse osmosis concentrate obtained by the secondary reverse osmosis component 33 is discharged through the second outlet end of the secondary reverse osmosis component 33. The recycling module of this invention is used to perform secondary reverse osmosis on the permeate obtained from the reverse osmosis module to obtain pure organic solvent (secondary reverse osmosis permeate), which is then returned to the dissolving module, allowing the permeate to be reused and realizing resource utilization. Preferably, the recirculation device is a circulation pump.

[0037] like Figure 2 As shown, the reuse module further includes a storage tank 31 and a second conveying device 32. The second conveying device 32 is disposed between the storage tank 31 and the secondary reverse osmosis assembly 33. The storage tank 31 is used to store the permeate obtained from the reverse osmosis assembly 22. The inlet end of the storage tank 31 is connected to the second outlet end of the reverse osmosis assembly 22, the outlet end of the storage tank 31 is connected to the inlet end of the second conveying device 32, and the outlet end of the second conveying device 32 is connected to the inlet end of the secondary reverse osmosis assembly 33. Preferably, the second conveying device is a high-pressure pump 32.

[0038] Please continue reading. Figure 2 The crude lithium difluorosulfonylimide enters the dissolution module through the inlet of the dissolution module. The dissolution module is configured to dissolve the crude lithium difluorosulfonylimide in an organic solvent to form a mixed solution. The mixed solution is then pumped to the reverse osmosis module by a high-pressure pump. The mixed solution is purified and concentrated through the reverse osmosis membrane of the reverse osmosis module to obtain a concentrate and a permeate. The concentrate is then evaporated and crystallized in the evaporation and crystallization module to obtain pure lithium difluorosulfonylimide. The permeate is pumped to the secondary reverse osmosis module for secondary reverse osmosis purification to obtain secondary reverse osmosis permeate and secondary reverse osmosis concentrate. The secondary reverse osmosis concentrate is discharged, and the secondary reverse osmosis permeate is collected in a recycling tank and then pumped back into the dissolution module, thus completing the cycle.

[0039] This invention discloses a purification system for lithium bis(fluorosulfonyl)imide. On one hand, it efficiently removes impurities from lithium bis(fluorosulfonyl)imide, producing high-purity lithium bis(fluorosulfonyl)imide with a purity of up to 99.98% and a yield of up to 98.6%. On the other hand, a concentration system concentrates the lithium bis(fluorosulfonyl)imide solution, increasing the concentration of the concentrated lithium bis(fluorosulfonyl)imide and reducing the amount of organic solvent transported to the evaporation and crystallization module, thereby reducing the investment cost of the evaporation and crystallization module. Furthermore, this lithium bis(fluorosulfonyl)imide purification system incorporates a recycling module, enabling the recovery and reuse of waste organic solvents, which helps protect the environment and reduce costs.

[0040] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0041] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications and variations to the above embodiments within the scope of the present invention.

Claims

1. A purification system for lithium bisfluorosulfonimide, characterized by, It includes a dissolution module, a concentration module, and an evaporation and crystallization module; The dissolving module has an inlet end and an outlet end. The concentration module includes a reverse osmosis component, which has an inlet end and an outlet end. The outlet end of the dissolution module is connected to the inlet end of the reverse osmosis component. The evaporation crystallization module has an inlet end and an outlet end, and the inlet end of the evaporation crystallization module is connected to the outlet end of the reverse osmosis component. The crude lithium difluorosulfonylimide enters the dissolution module through the inlet end of the self-dissolution module. The dissolution module is configured to dissolve the crude lithium difluorosulfonylimide in an organic solvent to form a mixed solution. The reverse osmosis component is configured to purify and concentrate the mixed solution to obtain a concentrate and a permeate. The evaporation and crystallization module is configured to evaporate and crystallize the concentrate obtained by the reverse osmosis component to obtain pure lithium difluorosulfonylimide.

2. The purification system of lithium bisfluorosulfonimide according to claim 1, characterized in that, The concentration module also includes a first conveying device; A first conveying device is disposed between the dissolution module and the reverse osmosis component. The outlet end of the dissolution module is connected to the inlet end of the first conveying device, and the outlet end of the first conveying device is connected to the inlet end of the reverse osmosis component. The outlet end of the reverse osmosis component includes a first outlet end and a second outlet end of the reverse osmosis component, and the first outlet end of the reverse osmosis component is connected to the inlet end of the evaporation crystallization module.

3. The purification system for lithium bis(fluorosulfonyl)imide according to claim 2, characterized in that, It also includes a reuse module; The inlet of the reuse module is connected to the second outlet of the reverse osmosis component, and the outlet of the reuse module is connected to the inlet of the dissolution module. The reuse module is used to perform secondary reverse osmosis on the permeate obtained from the reverse osmosis component and to return the secondary reverse osmosis permeate obtained from the secondary reverse osmosis to the dissolution module.

4. The purification system for lithium bis(fluorosulfonyl)imide according to claim 3, characterized in that, The reuse module includes a secondary reverse osmosis component, a reuse tank, and a reflux device. The inlet end of the secondary reverse osmosis component is connected to the outlet end of the reverse osmosis component. The first outlet end of the secondary reverse osmosis component is connected to the inlet end of the reuse tank. The outlet end of the reuse tank is connected to the inlet end of the reflux device. The outlet end of the reflux device is connected to the inlet end of the dissolution module. The secondary reverse osmosis module is used to purify the permeate obtained from the reverse osmosis module to obtain secondary reverse osmosis permeate and secondary reverse osmosis concentrate; The recycling tank is used to store the secondary reverse osmosis permeate purified by the secondary reverse osmosis module. The reflux device is used to return the stored secondary reverse osmosis permeate to the dissolution module. The secondary reverse osmosis concentrate obtained by the secondary reverse osmosis module is discharged through the second outlet end of the secondary reverse osmosis module.

5. The purification system for lithium bis(fluorosulfonyl)imide according to claim 4, characterized in that, The reuse module also includes a liquid storage tank; The inlet of the storage tank is connected to the second outlet of the reverse osmosis component, and the outlet of the storage tank is connected to the inlet of the secondary reverse osmosis component. The storage tank is used to store the permeate obtained by the reverse osmosis component.

6. The purification system for lithium bis(fluorosulfonyl)imide according to claim 5, characterized in that, The reuse module also includes a second conveying device; The second conveying device is disposed between the liquid storage tank and the secondary reverse osmosis component. The outlet end of the liquid storage tank is connected to the inlet end of the second conveying device, and the outlet end of the second conveying device is connected to the inlet end of the secondary reverse osmosis component.

7. The purification system for lithium bis(fluorosulfonyl)imide according to claim 4, characterized in that, The reflux device is a circulating pump, and both the first conveying device and the second conveying device are high-pressure pumps.

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