CN114408883A - Method for recovering lithium bis (fluorosulfonyl) imide - Google Patents

Method for recovering lithium bis (fluorosulfonyl) imide Download PDF

Info

Publication number
CN114408883A
CN114408883A CN202210110593.1A CN202210110593A CN114408883A CN 114408883 A CN114408883 A CN 114408883A CN 202210110593 A CN202210110593 A CN 202210110593A CN 114408883 A CN114408883 A CN 114408883A
Authority
CN
China
Prior art keywords
lifsi
effluent
colorimetric value
lithium
carbonate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210110593.1A
Other languages
Chinese (zh)
Inventor
程思聪
黄起森
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Contemporary Amperex Technology Co Ltd
CATL Sicong Novel Materials Co Ltd
Original Assignee
Contemporary Amperex Technology Co Ltd
CATL Sicong Novel Materials Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Contemporary Amperex Technology Co Ltd, CATL Sicong Novel Materials Co Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to CN202210110593.1A priority Critical patent/CN114408883A/en
Publication of CN114408883A publication Critical patent/CN114408883A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00Nitrogen; Compounds thereof
    • C01B21/082Compounds containing nitrogen and non-metals and optionally metals
    • C01B21/086Compounds containing nitrogen and non-metals and optionally metals containing one or more sulfur atoms
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00Physical properties of inorganic compounds
    • C01P2006/80Compositional purity

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Secondary Cells (AREA)

Abstract

The application provides a method for recovering lithium bis (fluorosulfonyl) imide. The method of the present application comprises: mixing waste residues from a process for manufacturing lithium bis (fluorosulfonyl) imide with a carbonate solvent to obtain a mixture; carrying out solid-liquid separation on the mixture to obtain liquid and solid slag; monitoring the colorimetric value of the effluent liquid, and comparing the colorimetric value of the effluent liquid with a reference colorimetric value; when the colorimetric value of the effluent is larger than the reference colorimetric value, circulating the effluent into the mixture; and when the colorimetric value of the effluent is less than or equal to the reference colorimetric value, recycling the effluent to the manufacturing process of the lithium bis (fluorosulfonyl) imide.

Description

Method for recovering lithium bis (fluorosulfonyl) imide
Technical Field
The application belongs to the field of chemical manufacturing, and particularly relates to a method for recovering lithium bis (fluorosulfonyl) imide from waste residues generated in a lithium bis (fluorosulfonyl) imide manufacturing process.
Background
Lithium bis (fluorosulfonylimide) (chemical formula Li [ N (SO) ]2F)2]Hereinafter abbreviated as LiFSI) is an important fluorine-containing lithium salt, due to its specific molecular structure, Li+And FSI-Has lower binding energy between them, is beneficial to Li+Thereby, the higher conductivity can be obtained by adding LiFSI into the electrolyte of the secondary battery. Meanwhile, LiFSI also has the characteristics of high thermal stability, wider electrochemical window and lower corrosion rate. When LiFWhen the SI is applied to a power battery, the cycle performance and the rate capability of the power battery can be improved, and the SI is expected to be used as an electrolyte lithium salt in a lithium ion battery.
At present, LiFSI is high in production cost due to the limitation of synthesis process conditions, and the existing manufacturing process has the defects of scarce raw materials, complex process, long flow, low product conversion rate, high energy consumption, environmental pollution and the like. In addition, as an electrolyte for a lithium ion secondary battery, it is required to satisfy severe requirements such as high purity and no water. Residual moisture in LiFSI is difficult to remove completely by heating to bring water, drying to remove water until decomposition, or even if it can be removed, it will lose a large yield.
Therefore, how to recover the residual LiFSI from the waste slag of the LiFSI manufacturing process as much as possible to improve the yield of the LiFSI manufacturing process is a problem that needs to be solved by those skilled in the art.
Disclosure of Invention
In view of the above problems in the background art, the present application aims to provide a method for recovering lithium bis (fluorosulfonyl) imide from waste residues of a LiFSI manufacturing process, so as to improve the yield of the LiFSI manufacturing process, maximize the recovery and utilization, and reduce environmental pollution.
To achieve the above objects, in one aspect, the present application provides a method of recovering LiFSI, comprising:
mixing waste residue from a LiFSI manufacturing process with a carbonate solvent to obtain a mixture;
carrying out solid-liquid separation on the mixture to obtain liquid and solid slag;
monitoring the colorimetric value of the effluent liquid, and comparing the colorimetric value of the effluent liquid with a reference colorimetric value;
when the colorimetric value of the effluent is larger than the reference colorimetric value, circulating the effluent into the mixture; and
and when the colorimetric value of the effluent is less than or equal to the reference colorimetric value, circulating the effluent to the LiFSI manufacturing process.
Thus, the present application provides for the utilization of carbonate-based solvents in the production of LiFSI from waste residuesIn the process of recycling LiFSI, the colorimetric value of the effluent obtained by solid-liquid separation is monitored, so that LiFSI and other lithium salts in waste residue, such as lithium sulfate (Li)2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) The isolated condition of (1). And only when the colorimetric value of the discharged liquid is less than or equal to the preset reference colorimetric value, the discharged liquid is circulated to the LiFSI manufacturing process, and the residual LiFSI in the waste slag can be recycled to the manufacturing process so as to realize the maximization of LiFSI recycling. Furthermore, lithium sulfate (Li) in the recovered LiFSI-containing material2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) Etc. are sufficiently removed. Lithium sulfate (Li) can be recovered from the solid slag obtained from the recovery process by further treatment2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) And lithium salt is added to realize the full utilization of lithium resource and reduce environmental pollution.
In any embodiment, the reference chromaticity value is a number no greater than 300Hazen, and optionally no greater than 200 Hazen.
In any embodiment, the carbonate-based solvent is one or more of diethyl carbonate (DEC), Ethyl Methyl Carbonate (EMC), dimethyl carbonate (DMC), Ethylene Carbonate (EC), and Propylene Carbonate (PC).
In any embodiment, the mass ratio of the waste residue to the carbonate solvent is 1 (1-5), and optionally 1 (2-4).
In any embodiment, the solid-liquid separation is performed by centrifugation.
In any embodiment, the solid-liquid separation is performed by filtration.
In any embodiment, the primary recovery of bis-fluorosulfonylimide is not less than 85%.
The method for recovering the LiFSI from the waste residues in the LiFSI manufacturing process can improve the yield of the LiFSI manufacturing process, realize the maximization of LiFSI recovery and utilization, and reduce environmental pollution.
Drawings
Fig. 1a and 1b are process flow diagrams of section a of a LiFSI manufacturing process of an embodiment of the present application.
Fig. 2 is a process flow diagram for the beta section of the LiFSI manufacturing process of an embodiment of the present application.
Fig. 3 is a process flow diagram of the crystallization and drying sequence of the LiFSI manufacturing process of the example of the present application.
Fig. 4 is a process flow diagram of a dissolution sequence of the LiFSI manufacturing process of an embodiment of the present application.
FIG. 5 is a process flow diagram of the recovery process of example 1.
Detailed Description
Hereinafter, embodiments of the method for recovering lithium bis (fluorosulfonyl) imide according to the present application will be specifically disclosed in detail with reference to the accompanying drawings as appropriate. But a detailed description thereof will be omitted. For example, detailed descriptions of already known matters and repetitive descriptions of actually the same configurations may be omitted. This is to avoid unnecessarily obscuring the following description, and to facilitate understanding by those skilled in the art. The drawings and the following description are provided for those skilled in the art to fully understand the present application, and are not intended to limit the subject matter recited in the claims.
The "ranges" disclosed herein are defined in terms of lower limits and upper limits, with a given range being defined by a selection of one lower limit and one upper limit that define the boundaries of the particular range. Ranges defined in this manner may or may not include endpoints and may be arbitrarily combined, i.e., any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In this application, unless otherwise stated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0 to 5" means that all real numbers between "0 to 5" have been listed herein, and "0 to 5" is simply a shorthand representation of the combination of these values. In addition, when a parameter is an integer of 2 or more, it is equivalent to disclose that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or the like.
All embodiments and alternative embodiments of the present application may be combined with each other to form new solutions, if not specifically stated.
All technical and optional features of the present application may be combined with each other to form new solutions, if not otherwise specified.
All steps of the present application may be performed sequentially or randomly, preferably sequentially, if not specifically stated. For example, the method comprises steps (a) and (b), meaning that the method may comprise steps (a) and (b) performed sequentially, and may also comprise steps (b) and (a) performed sequentially. For example, reference to the process further comprising step (c) means that step (c) may be added to the process in any order, for example, the process may comprise steps (a), (b) and (c), may also comprise steps (a), (c) and (b), may also comprise steps (c), (a) and (b), etc.
The references to "comprising" or "including" in this application are to be construed as open ended as well as closed ended, unless expressly stated otherwise. For example, the terms "comprising" and "comprises" may mean that other components not listed may also be included or included, or that only listed components may be included or included.
In this application, the term "or" is inclusive, if not otherwise specified. For example, the phrase "a or B" "means" a, B, or both a and B ". More specifically, either of the following conditions satisfies the condition "a or B": a is true (or present) and B is false (or not present); a is false (or not present) and B is true (or present); or both a and B are true (or present).
The application provides a method for recovering lithium bis (fluorosulfonyl) imide, comprising:
mixing waste residues from a process for manufacturing lithium bis (fluorosulfonyl) imide with a carbonate solvent to obtain a mixture;
carrying out solid-liquid separation on the mixture to obtain liquid and solid slag;
monitoring the colorimetric value of the effluent liquid, and comparing the colorimetric value of the effluent liquid with a reference colorimetric value;
when the colorimetric value of the effluent is larger than the reference colorimetric value, circulating the effluent into the mixture; and
and when the colorimetric value of the effluent is less than or equal to the reference colorimetric value, recycling the effluent to the manufacturing process of the lithium bis (fluorosulfonyl) imide.
Although the mechanism is not clear, the applicant has surprisingly found that: the colorimetric values of LiFSI solutions vary with the concentration of LiFSI and the presence of other lithium salts in the solution. At a concentration of about 30 wt%, a solution of LiFSI in a carbonate-based solvent has a chroma value of about 40. When other lithium salts, e.g. lithium sulphate (Li), are present in the solution2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) The turbidity caused by these lithium salts will increase the chroma value of the solution. When solid-liquid separation is carried out on a mixture of waste residue from a LiFSI manufacturing process and a carbonate solvent, LiFSI dissolved in the carbonate solvent enters effluent, and other lithium salts such as lithium sulfate (Li) are added2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) Then solid slag is entered. In the process, the more thorough the solid-liquid separation is, the less the amount of LiFSI remained in the solid residue, and other lithium salts such as lithium sulfate (Li) remained in the effluent2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) The lower the content of (A), the smaller the chroma value of the effluent. Therefore, in the process of recovering LiFSI from waste residue in the LiFSI manufacturing process by using carbonate solvents, the colorimetric value of effluent obtained by solid-liquid separation can reflect LiFSI and other lithium salts in the waste residue, such as lithium sulfate (Li)2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) The isolated condition of (1).
Only when the colorimetric value of the effluent is less than or equal to the preset reference colorimetric value, the effluent is circulated to the LiFSI manufacturing process, and the residual LiFSI in the waste slag can be recycledIn the manufacturing process, the recycling of LiFSI is maximized. Furthermore, lithium sulfate (Li) in the recovered effluent2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) Etc. are sufficiently removed. Lithium sulfate (Li) can be recovered from the solid slag obtained from the recovery process by further treatment2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) And lithium salt is added to realize the full utilization of lithium resource and reduce environmental pollution.
According to the method, in the process of recycling LiFSI from waste residues generated in the LiFSI manufacturing process by utilizing the carbonate solvent, the colorimetric value of the effluent obtained by solid-liquid separation is monitored, and the LiFSI and other lithium salts in the waste residues, such as lithium sulfate (Li)2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) The isolated condition of (1).
In some embodiments, the reference chromaticity value is a number no greater than 300Hazen, optionally no greater than 200 Hazen. When the color value of the effluent is low, the effluent is circulated to a LiFSI manufacturing process, so that the solid-liquid separation can be fully performed, the quantity of LiFSI remained in solid slag is fully reduced, and the content of LiFSI in the effluent recycled to the LiFSI manufacturing process is increased, thereby improving the recycling of LiFSI. When the reference chromatic value is not more than 300Hazen, the primary recovery rate of LiFSI recovered from the waste residue can reach more than 85%. When the reference chromatic value is not more than 200Hazen, the primary recovery rate of the LiFSI recovered from the waste slag can reach more than 92%.
In the present application, the carbonate solvent is not particularly limited as long as the carbonate solvent can dissolve LiFSI, and those skilled in the art can select the carbonate solvent according to actual needs. In some embodiments, the carbonate-based solvent is one or more of diethyl carbonate (DEC), Ethyl Methyl Carbonate (EMC), dimethyl carbonate (DMC), Ethylene Carbonate (EC), and Propylene Carbonate (PC). In the present application, the carbonate solvent is not particularly limited as long as the carbonate solvent can dissolve LiFSI, and those skilled in the art can select the carbonate solvent according to actual needs.
In the present application, as long as the LiFSI in the waste residue can be sufficiently dissolved in the carbonate solvent, the mass ratio of the waste residue to the carbonate solvent is not particularly limited, and those skilled in the art can select the LiFSI according to actual requirements. In some embodiments, the mass ratio of the waste residue to the carbonate solvent is 1 (1-5), and optionally 1 (2-4).
In the application, as long as the solid-liquid separation of the mixture can be realized, the specific manner of the solid-liquid separation is not limited, and a person skilled in the art can select the solid-liquid separation according to actual requirements. In some embodiments, the solid-liquid separation is performed by centrifugation. In some embodiments, the solid-liquid separation is performed by filtration.
In some embodiments, the primary recovery of bis-fluorosulfonylimide is not less than 85%.
In the method, the colorimetric value of the effluent obtained by solid-liquid separation is monitored in the process of recovering LiFSI from the waste residue in the LiFSI manufacturing process by utilizing the carbonate solvent, so that LiFSI and other lithium salts in the waste residue, such as lithium sulfate (Li)2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) The isolated condition of (1). Only when the colorimetric value of the discharged liquid is less than or equal to the preset reference colorimetric value, the discharged liquid is circulated to the LiFSI manufacturing process, and the residual LiFSI in the waste slag can be recycled to the manufacturing process, so that the maximum recycling of the LiFSI is realized. Furthermore, lithium sulfate (Li) in the recovered LiFSI-containing material2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) Etc. are sufficiently removed. Lithium sulfate (Li) can be recovered from the solid slag obtained from the recovery process by further treatment2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) And lithium salt is added to realize the full utilization of lithium resource and reduce environmental pollution.
Examples
Hereinafter, examples of the present application will be described. The following description of the embodiments is merely exemplary in nature and is in no way intended to limit the present disclosure. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
LiFSI manufacturing process
As an example, the method of recovering LiFSI of the present application may be applied to a LiFSI manufacturing process including the following steps. An exemplary LiFSI manufacturing process is described below with reference to fig. 1a, 1b, and 2-4.
Synthesizing: the sulfuryl fluoride, ammonia gas and triethylamine are fully mixed, the sulfuryl fluoride and the ammonia gas are fully reacted, and the triethylamine serves as a solvent and participates in the reaction. Other organic solvents, such as acetonitrile, may also be used as a solvent for the reaction. The main reaction is SO2F2+NH3+Et3N→(SO2F-NH-SO2F)·Et3N+Et3N·(HF)n(n=1~12)。
When the temperature in the reaction vessel is too high, the following side reactions occur to affect the yield: NH (NH)3+SO2F2+Et3N→NH2-SO2-NH2(sulfamide, solid) + Et3N·(HF)n(triethylamine hydrogen fluoride, dissolved in CH)3And in CN, n is 1-12). After the reaction, the by-product sulfonamide solids can be filtered off using, for example, a 5 μm tetrafluoro filter bag.
After the synthesis process, the material composition mainly comprises (SO)2F-NH-SO2F)·Et3N, acetonitrile, triethylamine hydrogen fluoride, triethylamine (in small amounts), and impurity ions. The impurity ions mainly contain F-、SO4 2-、FSO3 -And Cl-
And (3) evaporation: the product mixture (feed α 1) was evaporated in an evaporator and the acetonitrile solvent was separated off. The material can be heated by a falling film evaporator, the liquid and the steam are separated by a gas-liquid separator, and the steam acetonitrile (containing a small amount of triethylamine) is condensed by a condenser and is recycled for the first step of synthesis.
After the evaporation process, the material composition mainly comprises (SO)2F-NH-SO2F)·Et3N, triethylamine hydrogen fluoride, acetonitrile (trace), and impurity ions.
And (3) extraction: the concentrated solution (material alpha 2) obtained by evaporation is washed by water, and impurities (mainly triethylamine hydrogen fluoride) which are easy to dissolve in water are washed away. Two schemes can be used for this:
the first scheme is that the bottom of the extraction tower is filled with a light phase (with low density), the upper part of the extraction tower is filled with the light phase, the top of the extraction tower is filled with a heavy phase, the bottom of the extraction tower is filled with the heavy phase, and the middle of the extraction tower is stirred to be spiral; scheme two, a static mixer and a stratification tank. The extract oil phase (material alpha 3) mainly comprises (SO)2F-NH-SO2F)·Et3N, while the aqueous extract phase (feed alpha water) contains predominantly triethylamine hydrogen fluoride and impurity ions (e.g. F)-、SO4 2-、FSO3 -、Cl-). In the scheme of extraction by using the extraction tower, the impurity ions (such as F) can be used-) Better separation. In the scheme of extraction by using the static mixer, the content of the impurity ions in the oil phase obtained by extraction by the static mixer is about 5 to 30 times, optionally about 10 to 20 times, that of the impurity ions in the oil phase obtained by extraction by the extraction tower. Optionally, the impurity ion is F-. In the LiFSI manufacturing process, the stage of synthesis-evaporation-extraction can be referred to as the α -stage, and the specific flow scheme can be referred to as the process flow scheme of fig. 1a (extraction column scheme) or fig. 1b (static mixer scheme) in the present application.
Alkalization: mixing the extracted oil phase (material alpha 3) obtained after extraction with the lithium hydroxide aqueous solution and fully reacting. The reaction is reaction 2: (SO)2F-NH-SO2F)·Et3N+LiOH→(SO2F-N-SO2F)-Li++Et3N+H2And O. The reaction principle is that strong base replaces weak base, and the alkalinity of LiOH is higher than (SO)2F-NH-SO2F)·Et3Triethylamine in N, so that triethylamine is displaced. Triethylamine was removed by falling film evaporator B with LiOH and (SO)2F-NH-SO2F)·Et3N reacts to form lithium salt LiFSI.
And (3) dehydrating: the reaction mixture obtained in reaction 2 (feed β 1) was dehydrated using a falling-film evaporator C. The ester solvent is adopted to carry water, and no chemical reaction is involved. Since lithium salts have very strong water absorption, it is not practical to reduce the water content to the target level simply by evaporation. The addition of a large amount of ester solvent can weaken the water adsorption of the lithium salt, and the water content can be reduced to the target requirement in the process of evaporating the ester solvent while adding the ester solvent. The ester solvent can be recycled after being purified by a recovery section. The ester solvent may include Ethyl Methyl Carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and the like. LiFSI is also decomposed during dehydration to produce lithium sulfate (Li) as a by-product2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) And the like. The solid by-product is filtered or centrifuged (e.g., using centrifugal settling to remove solids, such as a scraper centrifuge or disk centrifuge) to obtain a reject before the next desolventizing step.
Removing the by-products LiF and Li from the waste residue from the dehydration process2SO4Lithium sulfamate, etc., a small amount of LiFSI product also inevitably remains. By the method for recycling the LiFSI, the residual LiFSI in the waste residue can be recycled to any falling film evaporator.
Desolventizing: and (3) desolventizing the evaporated and dehydrated material (material beta 2) in a falling-film evaporator D and a scraper evaporator E which are connected in series. The desolventization does not involve a reaction, but is only for the purpose of evaporating off the ester solvent. Since the lithium salt is dissolved in the ester solvent, if the ester solvent is not evaporated to a certain extent (e.g., from 60% to 65% to 30%), the crystallization cannot be performed in the later stage or the crystallization rate is very low. The ester solvent can be recycled after being purified by a recovery section. The crude LiFSI (feed beta 3) with a low water content (e.g.less than 3000ppm) is obtained after the desolventizing step. In the LiFSI manufacturing process, the stage of alkalization-dehydration-desolventization can be referred to as β stage, and the specific flow chart can refer to the process flow chart of fig. 2 in the present application.
In the dehydration and desolventizing processes, in order to avoid the decomposition of the LiFSI product in the evaporation process, a lithium hydroxide aqueous solution is continuously added, and the pH value is kept between 7 and 9, so that a weakly alkaline system is kept, and the decomposition of the LiFSI product is inhibited. In the desolventizing process, since the lithium hydroxide aqueous solution is added to introduce moisture, DEC is continuously added during the desolventizing process to carry water out.
And (3) crystallization: by crystallization is meant that when a substance is in a non-equilibrium state, additional phases are precipitated which precipitate in the form of crystals. The material beta 3 is introduced into a crystallization kettle, and dichloromethane is added. Methylene dichloride is used for dissolving the ester solvent but not the LiFSI, so that the LiFSI is supersaturated in the ester solvent to be separated out, and crystal nuclei grow. And introducing the obtained mixture into a two-in-one device with a filtering and washing function, and washing off other impurities attached to the surface of the LiFSI crystal. After the crystallization liquid is purified by a recovery section, the ester solvent and the dichloromethane can be recycled.
Although not shown in fig. 2, those skilled in the art can filter or centrifuge the solid by-product to obtain the waste residue before the dehydration step and/or the crystallization step according to actual needs. These residues can also be applied to the method for recovering LiFSI of the present application, and the recovered LiFSI can be recycled to any falling film evaporator.
And (3) drying: and (4) introducing the washed materials into a drying kettle. After heating nitrogen, the mixture is introduced into a drying kettle. The material is fluidized under the action of stirring and airflow, and in the large-area gas-solid two-phase contact, the moisture of the material is quickly evaporated, and high-humidity nitrogen is discharged out of the kettle, so that the material meets the drying requirement. The specific process of the crystallization and drying steps can be referred to the process flow chart of FIG. 3 of the present application
In the LiFSI production process, the material β 3 may be directly put into the dissolving process without performing the above-described crystallization and drying steps.
Dissolving: in the dissolving process, the crystals in the above drying kettle (for crystallization process) or the crude product beta 3 (for non-crystallization process) can be dissolved by using ester solvent such as methyl ethyl carbonate (EMC) or dimethyl carbonate (DMC) according to the requirement, the acid is removed (if the HF content in the detected solution is excessive (such as standard HF is less than or equal to 50 μ g/g), LiOH is used for removing acid), the water is removed (if the moisture content in the detected solution is excessive (such as standard moisture is less than or equal to 20 μ g/g), the solution is passed through a molecular sieve, concentrated, filtered by a filter core and stored (such as barreling or tank loading).
Measuring method
(1) Colorimetric measurement method
First, a 500Hazen platinum-cobalt standard solution was prepared. Specifically, 1.246g of potassium chloroplatinate (K) was weighed2PtCl6) And 1.000g of dried cobalt chloride hexahydrate (CoCl)2·6H2O) was dissolved in 100mL of pure water, 100mL of hydrochloric acid (ρ 20 ═ 1.19g/mL) was added, and the volume was adjusted to 1000mL with pure water, to obtain a 500Hazen platinum-cobalt standard solution. Then, a series of standard solutions having different color values (e.g., 20Hezen, 30Hezen, 40Hezen, etc.) were prepared from the 500Hazen platinum-cobalt standard solution according to the formula V ═ N/5, where N is the color value of the standard solution to be prepared (Hezen) and V is the volume of the 500Hezen standard solution (mL) required to prepare 100mL of the standard solution.
And respectively filling the prepared series of platinum-cobalt standard solutions into 50mL colorimetric tubes, and placing the colorimetric tubes on a colorimetric frame according to the chromaticity. A white background is placed in the light source box, a 25mL sample is placed in a 50mL colorimetric tube and placed in the middle of the bottom plate of the light source box. And comparing the sample to be detected with the platinum-cobalt standard solution in the standard light source box along the axis direction of the colorimetric tube by a visual method, and taking the colorimetric value of the standard solution with the color value which is darker than the colorimetric value of the sample to be detected and is the smallest as the colorimetric value of the sample.
(2) Method for measuring amount of LiFSI
And (3) measuring the LiFSI content in the LiFSI manufacturing process waste residue and the solid residue obtained by the recovery process by adopting an ion exchange chromatography (IC), so as to obtain the LiFSI content in the waste residue or the solid residue.
Specifically, the mass fraction of LiFSI in the slag or solid slag with respect to the total mass was measured using a chromatograph (dean ICs-900, usa saimenfei) equipped with an ion exchange chromatography column (analytical column Shodex IC SI-904E, 4.6 × 250mm, guard column Shodex IC SI-90G, 4.6 × 10mm), and the amount of LiFSI contained in the slag or solid slag was finally obtained. The ion exchange chromatography operating parameters were as follows: the temperature of the chromatographic column is 30-45 ℃, the detector is a DS5 conductivity detector, and the leacheate is 1.8mmol of Na2CO3+1.8mmol NaHCO3+ 20% acetonitrile (V/V), flow rate of eluting solution is 1.0mL/min, and regeneration solution is 20mmol H2SO4The flow rate of the regeneration liquid was 1.0 mL/min.
(3) Method for measuring content of impurity ions in effluent
Measuring SO in the effluent obtained by solid-liquid separation by ion exchange chromatography (IC)4 2-Content and NH2SO3 -And (4) content.
Specifically, SO in the effluent was measured using a chromatograph (Danan ICS-900, Saimeisha fly, USA) equipped with an ion exchange chromatography column (analytical column Shodex IC SI-904E, 4.6X 250mm, guard column Shodex IC SI-90G, 4.6X 10mm)4 2-Content and NH2SO3 -And (4) content. The ion exchange chromatography operating parameters were as follows: the temperature of the chromatographic column is 30-45 ℃, the detector is a DS5 conductivity detector, and the leacheate is 1.8mmol of Na2CO3+1.8mmol NaHCO3+ 20% acetonitrile (V/V), flow rate of eluting solution is 1.0mL/min, and regeneration solution is 20mmol H2SO4The flow rate of the regeneration liquid was 1.0 mL/min.
Example 1
Waste residues from a LiFSI manufacturing process and an ester solvent DEC are stirred in a mixing kettle in a mass ratio of 1: 3. Opening the ester solvent feed valve of the mixing kettle, feeding DEC, and opening 10m3Stirring the mixing kettle, and then feeding waste residues. The mass ratio of the fed waste slag to DEC is 1: 3. Stirring for half an hour, and then using 2m3And (4) centrifuging the materials in the mixing kettle by using a centrifugal machine (PLGZ-30000, a petrochemical equipment without tin and Hongtong). Specifically, the mixing kettle bottom valve and the outlet valve of the centrifuge feed pump are opened, the centrifuge feed pump is started, and the centrifuge is started to feed. After the feeding is finished, the centrifuge is started, and the centrifugal treatment is carried out at the rotating speed of 12000rpm, wherein the speed-up time is 120s, and the centrifugal time is 30 min. And after the centrifugal treatment is finished, opening a liquid outlet valve of the centrifugal processor, opening an emptying valve of a storage tank for receiving the centrifugal liquid outlet, and collecting the centrifugal liquid outlet.
The centrifuge effluent was monitored for color by the colorimetric measurement method described above and compared to a reference color value of 40 Hazen. If the chroma is more than 40Hazen, the effluent is sent to a mixing kettle for retreatment; if the color of the effluent is less than or equal to 40Hazen) is directly returned to the falling-film evaporator (such as the falling-film evaporator B, C or D shown in FIG. 2) of the LiFSI manufacturing process.
The specific process flow of the method for recovering LiFSI of example 1 can be referred to the process flow diagram of fig. 5 of the present application.
By the measurement method described above, it was determined that the slag from the LiFSI manufacturing process contained 13.4kg of LiFSI. After the recovery treatment, the amount of LiFSI in the solid slag leaving the centrifugal processor is only 0.4 kg. The primary recovery rate of LiSFI was 97.0%, as determined by the following equation.
The one-time recovery rate of LiFSI is (1-the amount of LiFSI in the solid slag after treatment/the amount of LiFSI in the waste slag before treatment) multiplied by 100 percent
In addition, SO was measured in the effluent leaving the centrifugal processor4 2-Content and NH2SO3 -The contents were 17.6ppm and 15.6ppm, respectively.
Examples 2 to 17
Lithium bis (fluorosulfonylimide) remaining in the waste residue from the bis (fluorosulfonylimide) production process was recovered to the LiFSI production process by substantially the same method as in example 1, except that the reference colorimetric values used when the recovery was performed were as shown in table 1.
The amount of LiFSI contained in the waste residue from the bis (fluorosulfonyl) imide production process, the amount of LiFSI contained in the solid residue leaving the centrifugal processor after the above-mentioned recovery treatment, and the SO contained in the effluent leaving the centrifugal processor were measured by the above-mentioned measurement methods, respectively4 2-Content and NH2SO3 -Content and calculating the primary recovery rate of LiFSI. The results are shown in Table 1. The results of the experiment of example 1 are also shown in Table 1.
TABLE 1
Figure BDA0003494971130000121
As can be seen from the results of examples 1 to 17, in the production of LiFSI from DECIn the process of recycling LiFSI from waste residues, the colorimetric value of the effluent obtained by solid-liquid separation is monitored, when the reference colorimetric value is an optimal value not greater than 300Hazen, the colorimetric value of the effluent obtained by solid-liquid separation is monitored, and only when the colorimetric value of the effluent is less than or equal to the optimal reference colorimetric value, the effluent obtained by solid-liquid separation is circulated to a LiFSI manufacturing process, more than 85% of LiFSI in the waste residues can be recycled to the manufacturing process, and the maximization of LiFSI recycling is further realized. Furthermore, lithium sulfate (Li) in the recovered effluent2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) And the impurities are fully removed, and the content is all lower than 200 ppm.
In embodiments 1 to 17, when the reference colorimetric value is a further preferred numerical value not greater than 200Hazen, the colorimetric value of the effluent obtained by the solid-liquid separation is monitored, and only when the colorimetric value of the effluent is less than or equal to the further preferred reference colorimetric value, the effluent obtained by the solid-liquid separation is circulated to the LiFSI manufacturing process, so that more than 92% of LiFSI in the waste slag can be recovered to the manufacturing process, and the maximum recycling of LiFSI is further realized. Furthermore, lithium sulfate (Li) in the recovered effluent2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) And the impurities are fully removed, and the content is all lower than 100 ppm.
Those skilled in the art will recognize that lithium sulfate (Li) may also be recovered from the solid slag obtained from the recovery process of the present application by further processing2SO4) Lithium fluoride (LiF) and lithium sulfamate (LiNH)2SO3) And lithium salts are used to realize the full utilization of lithium resources and further reduce the environmental pollution.
The present application is not limited to the above embodiments. The above embodiments are merely examples, and embodiments having substantially the same configuration as the technical idea and exhibiting the same operation and effect within the technical scope of the present application are all included in the technical scope of the present application. In addition, various modifications that can be conceived by those skilled in the art are applied to the embodiments and other embodiments are also included in the scope of the present application, in which some of the constituent elements in the embodiments are combined and constructed, without departing from the scope of the present application.

Claims (7)

1. A method of recovering lithium bis (fluorosulfonyl) imide, comprising:
mixing waste residues from a process for manufacturing lithium bis (fluorosulfonyl) imide with a carbonate solvent to obtain a mixture;
carrying out solid-liquid separation on the mixture to obtain liquid and solid slag;
monitoring the colorimetric value of the effluent liquid, and comparing the colorimetric value of the effluent liquid with a reference colorimetric value;
when the colorimetric value of the effluent is larger than the reference colorimetric value, circulating the effluent into the mixture; and
and when the colorimetric value of the effluent is less than or equal to the reference colorimetric value, recycling the effluent to the manufacturing process of the lithium bis (fluorosulfonyl) imide.
2. The method of claim 1, wherein the reference chromaticity value is a number not greater than 300Hazen, optionally not greater than 200 Hazen.
3. The method according to claim 1 or 2, wherein the carbonate-based solvent is one or more of diethyl carbonate (DEC), Ethyl Methyl Carbonate (EMC) and dimethyl carbonate (DMC), Ethylene Carbonate (EC), Propylene Carbonate (PC).
4. The method according to any one of claims 1 to 3, wherein the mass ratio of the waste residue to the carbonate solvent is 1 (1-5), optionally 1 (2-4).
5. The method according to any one of claims 1 to 4, wherein the solid-liquid separation is performed by centrifugation.
6. The process of any one of claims 1 to 4, wherein the solid-liquid separation is carried out by filtration.
7. The process of any one of claims 1 to 6, wherein the primary recovery of bis-fluorosulfonylimide is not less than 85%.
CN202210110593.1A 2022-01-29 2022-01-29 Method for recovering lithium bis (fluorosulfonyl) imide Pending CN114408883A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210110593.1A CN114408883A (en) 2022-01-29 2022-01-29 Method for recovering lithium bis (fluorosulfonyl) imide

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210110593.1A CN114408883A (en) 2022-01-29 2022-01-29 Method for recovering lithium bis (fluorosulfonyl) imide

Publications (1)

Publication Number Publication Date
CN114408883A true CN114408883A (en) 2022-04-29

Family

ID=81279592

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210110593.1A Pending CN114408883A (en) 2022-01-29 2022-01-29 Method for recovering lithium bis (fluorosulfonyl) imide

Country Status (1)

Country Link
CN (1) CN114408883A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023241113A1 (en) * 2022-06-15 2023-12-21 时代思康新材料有限公司 Lifsi wastewater treatment method

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106241757A (en) * 2016-07-27 2016-12-21 上海康鹏科技有限公司 A kind of preparation method of imidodisulfuryl fluoride lithium salt
CN108387674A (en) * 2018-01-29 2018-08-10 九江天赐高新材料有限公司 A kind of assay method of double fluorine sulfimide lithium purity
FR3081720A1 (en) * 2018-06-01 2019-12-06 Arkema France PROCESS FOR RECOVERY AND / OR PURIFICATION OF A BIS POTASSIUM SALT (FLUOROSULFONYL) IMIDE
CN110692160A (en) * 2018-03-29 2020-01-14 三菱化学株式会社 Nonaqueous electrolyte solution and nonaqueous electrolyte battery
WO2020216736A1 (en) * 2019-04-25 2020-10-29 Arkema France Process for preparing bis(fluorosulfonyl) imide
CN111874880A (en) * 2020-08-10 2020-11-03 邵武永太高新材料有限公司 Solid waste recycling process and equipment for lithium bis (fluorosulfonyl) imide
CN112174101A (en) * 2020-09-23 2021-01-05 湖南博信新能源科技有限公司 Preparation method of high-purity lithium bis (fluorosulfonyl) imide
CN113582145A (en) * 2021-09-28 2021-11-02 江苏华盛锂电材料股份有限公司 Method for purifying lithium bis (fluorosulfonyl) imide
CN113603069A (en) * 2021-10-08 2021-11-05 江苏华盛锂电材料股份有限公司 Method for removing trace impurities in lithium bis (fluorosulfonyl) imide
CN113800485A (en) * 2021-09-18 2021-12-17 多氟多新材料股份有限公司 Preparation method of lithium bis (fluorosulfonyl) imide

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106241757A (en) * 2016-07-27 2016-12-21 上海康鹏科技有限公司 A kind of preparation method of imidodisulfuryl fluoride lithium salt
CN108387674A (en) * 2018-01-29 2018-08-10 九江天赐高新材料有限公司 A kind of assay method of double fluorine sulfimide lithium purity
CN110692160A (en) * 2018-03-29 2020-01-14 三菱化学株式会社 Nonaqueous electrolyte solution and nonaqueous electrolyte battery
FR3081720A1 (en) * 2018-06-01 2019-12-06 Arkema France PROCESS FOR RECOVERY AND / OR PURIFICATION OF A BIS POTASSIUM SALT (FLUOROSULFONYL) IMIDE
WO2020216736A1 (en) * 2019-04-25 2020-10-29 Arkema France Process for preparing bis(fluorosulfonyl) imide
CN111874880A (en) * 2020-08-10 2020-11-03 邵武永太高新材料有限公司 Solid waste recycling process and equipment for lithium bis (fluorosulfonyl) imide
CN112174101A (en) * 2020-09-23 2021-01-05 湖南博信新能源科技有限公司 Preparation method of high-purity lithium bis (fluorosulfonyl) imide
CN113800485A (en) * 2021-09-18 2021-12-17 多氟多新材料股份有限公司 Preparation method of lithium bis (fluorosulfonyl) imide
CN113582145A (en) * 2021-09-28 2021-11-02 江苏华盛锂电材料股份有限公司 Method for purifying lithium bis (fluorosulfonyl) imide
CN113603069A (en) * 2021-10-08 2021-11-05 江苏华盛锂电材料股份有限公司 Method for removing trace impurities in lithium bis (fluorosulfonyl) imide

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
张勇耀等: "废旧锂离子电池电解液回收研究", 《浙江化工》 *
张铜奇: "双氟磺酰亚胺锂的合成及应用研究进展", 《化工设计通讯》 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023241113A1 (en) * 2022-06-15 2023-12-21 时代思康新材料有限公司 Lifsi wastewater treatment method

Similar Documents

Publication Publication Date Title
US20220372592A1 (en) Method for extracting lithium by means of extraction-back extraction separation and purification
CN111960445A (en) Method for preparing battery-grade lithium carbonate by using lithium sulfate coarse ore and recycling by-products
CN114408883A (en) Method for recovering lithium bis (fluorosulfonyl) imide
CN114408884A (en) Lithium bis (fluorosulfonyl) imide, preparation method thereof, electrolyte and secondary battery
CN115207506A (en) Method for recovering electrolyte of waste lithium ion battery
CN106565956A (en) Method for comprehensive recycling of by-product slurry in polyphenylene sulfide productive process
CN109608485B (en) Method for continuously preparing lithium bis (oxalato) borate
EP3577710A1 (en) Method for producing a hygroscopic alkali metal salt electrolyte solution
CN102225798A (en) Comprehensive utilization method of desulfurization waste liquid
CN114380305A (en) Method for recovering raw and auxiliary materials in production of lithium bis (fluorosulfonyl) imide
CN117567290A (en) Recycling method of waste lithium batteries
CZ293993B6 (en) Process for preparing substantially anhydrous magnesium chloride
WO2023142046A1 (en) Method for recovering lithium bis(fluorosulfonyl)imide
CN102491406B (en) Method for preparing gallium sulfate
CN115417456B (en) Salt separation treatment method and system for sodium carbonate and sodium molybdate mixed salt solution
CN114573006B (en) Method for purifying and recovering lithium by-product lithium-containing crude sodium sulfate in lithium extraction process of nickel cobalt lithium manganate anode material recovery
CN110523396A (en) A kind of uranium separation method and uranium absorption material
CN114348978A (en) Lithium bis (fluorosulfonyl) imide, preparation method thereof, electrolyte and secondary battery
WO2023142028A1 (en) Method for recovering raw and auxiliary materials in production of lithium bis(fluorosulfonyl)imide
CN114684834A (en) Method for extracting lithium from clay type lithium ore
WO2021113948A1 (en) Process and method for refining lithium carbonate starting from an impure lithium chloride solution
CN112456519A (en) Method for recovering lithium hexafluorophosphate waste liquid
WO2023142023A1 (en) Lithium bis(fluorosulfonyl)imide and method for preparing same, electrolyte and secondary battery
CN108217698B (en) Method for recovering lithium from PPS (polyphenylene sulfite) catalyst waste residue
RU2795224C1 (en) Process and method for lithium carbonate purification based on a lithium chloride solution with impurities

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination