Method for treating heavy bis(fluorosulfonyl)imide residue

Abstract

Provided in the present application is a method for treating a heavy bis(fluorosulfonyl)imide residue, comprising the following step: causing a starting material system comprising the heavy bis(fluorosulfonyl)imide residue and an acidic aqueous solution to react to obtain a fluorine-containing acid solution and a crude sulfamic acid product, wherein the fluorine-containing acid solution can be used as a by-product acid, thereby saving treatment costs; and the crude sulfamic acid product can also be directly sold as a product, thereby reducing treatment costs, bringing economic benefits, and achieving resource recycling of the heavy bis(fluorosulfonyl)imide residue.

Description

A method for treating bis(fluorosulfonyl)imide heavy residue

[0001] This application claims priority to Chinese Patent Application No. 202410776173.6, filed on June 17, 2024, entitled "A Method for Treating Difluorosulfonylimide Heavy Slag", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of bis(fluorosulfonyl)imide heavy residue recovery technology, and in particular to a method for treating bis(fluorosulfonyl)imide heavy residue. Background Technology

[0003] Difluorosulfonylimide is widely used in lithium-ion batteries as a raw material for preparing lithium bisfluorosulfonylimide. Difluorosulfonylimide is obtained through purification methods, which produce bisfluorosulfonylimide residue. This residue is a viscous liquid with poor flowability, and its main components are bisfluorosulfonylimide, fluorosulfonic acid, and their small salts. Among them, bisfluorosulfonylimide and fluorosulfonic acid account for more than 95%. As the market demand for lithium bisfluorosulfonylimide increases, the production of lithium bisfluorosulfonylimide by enterprises continues to increase, which will generate more bisfluorosulfonylimide residue.

[0004] Therefore, there is an urgent need to develop a method for treating bis(fluorosulfonyl)imide heavy slag to achieve the resource-based recycling and utilization of the heavy slag. Summary of the Invention

[0005] This application provides a method for treating bis(fluorosulfonyl)imide heavy residue, which enables the resource-based recycling of the heavy residue and reduces processing costs.

[0006] This application provides a method for processing bis(fluorosulfonyl)imide heavy residue, comprising the following steps: reacting a raw material system including bis(fluorosulfonyl)imide heavy residue and an acidic aqueous solution to obtain a fluorinated acid solution and crude aminosulfonic acid.

[0007] Further, the bis(fluorosulfonyl)imide heavy residue is added to the acidic aqueous solution to carry out the reaction, and the addition time is 0.5-3 hours.

[0008] Furthermore, the acidic aqueous solution is at least one of sulfuric acid aqueous solution, nitric acid aqueous solution, and hydrochloric acid aqueous solution.

[0009] Furthermore, the acidic aqueous solution contains 50-98% acid by mass.

[0010] Furthermore, the mass ratio of the difluorosulfonamide heavy residue to the acidic aqueous solution is 1:(1-10).

[0011] Furthermore, the mass ratio of the difluorosulfonamide heavy residue to the acidic aqueous solution is 1:(3-10).

[0012] Furthermore, the reaction temperature is 30-100℃; and / or the reaction time is 1-10h.

[0013] Furthermore, the reaction process is accompanied by stirring at a speed of 100-500 rpm.

[0014] Furthermore, the method for treating the bis(fluorosulfonyl)imide heavy residue further includes: rinsing the crude aminosulfonic acid product with the acidic washing solution to obtain the aminosulfonic acid product and the rinsed acid solution; the acidic washing solution is selected from at least one of sulfuric acid aqueous solution, nitric acid aqueous solution and hydrochloric acid aqueous solution.

[0015] Furthermore, the rinsing process is performed 3-8 times; and / or, in the rinsing process, the amount of acidic washing solution used is 1-5 times the mass of the difluorosulfonyl imide heavy slag.

[0016] Furthermore, it also includes: using the fluorinated acid solution and / or the leaching acid solution as raw materials to prepare phosphorus pentafluoride.

[0017] This application provides a method for processing bis(fluorosulfonyl)imide heavy residue. By reacting a raw material system comprising bis(fluorosulfonyl)imide heavy residue and an acidic aqueous solution, a fluorinated acid solution and crude aminosulfonic acid are obtained. The fluorinated acid solution can be used as a by-product acid, saving processing costs. The crude aminosulfonic acid can also be sold directly as a product, reducing processing costs and bringing economic benefits, thus realizing the resource-based recycling of bis(fluorosulfonyl)imide heavy residue. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art are within the scope of protection of this application.

[0019] This application provides a method for processing bis(fluorosulfonyl)imide heavy residue, comprising the following steps: reacting a raw material system including bis(fluorosulfonyl)imide heavy residue and an acidic aqueous solution to obtain a fluorinated acid solution and crude aminosulfonic acid.

[0020] The bis(fluorosulfonyl)imide heavy residue in this application refers to the heavy residue generated during the purification process of bis(fluorosulfonyl)imide raw material. Its main components are bis(fluorosulfonyl)imide and its trace salts, as well as fluorosulfonic acid and its trace salts. In the bis(fluorosulfonyl)imide heavy residue, the proportion of bis(fluorosulfonyl)imide and fluorosulfonic acid is more than 95%. The bis(fluorosulfonyl)imide heavy residue is a viscous liquid with extremely poor fluidity. Currently, there is no existing technology that can utilize bis(fluorosulfonyl)imide resources.

[0021] This application utilizes a raw material system comprising bis(fluorosulfonyl)imide heavy residue and an acidic aqueous solution to generate fluorosulfonic acid, aminosulfonic acid, and hydrogen fluoride. The reaction principle is shown in Formula 1.

[0022] Specifically, the acidic aqueous solution dissolves the heavy sludge of difluorosulfonylimide, dispersing it in the solution and allowing it to react fully with the water. The resulting fluorosulfonic acid is a liquid phase that dissolves directly in the acidic aqueous solution. The generated hydrogen fluoride further dissolves in the acidic aqueous solution to form acid. A very small amount of hydrogen fluoride may overflow from the system; optionally, the hydrogen fluoride tail gas can be treated with an alkaline solution. The generated aminosulfonic acid is a solid phase that forms a precipitate in the raw material system and can be separated from the liquid by filtration.

[0023] This application provides a method for processing bis(fluorosulfonyl)imide heavy residue. By reacting a raw material system comprising bis(fluorosulfonyl)imide heavy residue and an acidic aqueous solution, a fluorinated acid solution and crude aminosulfonic acid are obtained. The fluorinated acid solution can be used as a by-product acid, saving processing costs. The crude aminosulfonic acid can also be sold directly as a product, reducing processing costs and bringing economic benefits, thus realizing the resource-based recycling of bis(fluorosulfonyl)imide heavy residue.

[0024] Furthermore, the raw material system can be tested by ion chromatography. When the anion content of difluorosulfonyl imide in the raw material system is 0, it can be determined that the reaction is complete, and at this time, difluorosulfonyl imide has been completely converted.

[0025] In this process, the bis(fluorosulfonyl)imide heavy residue is added to an acidic aqueous solution to carry out the above reaction, and the addition time is 0.5-3 hours. In this application, the addition time refers to the time required for the bis(fluorosulfonyl)imide heavy residue to be uniformly added to the acidic aqueous solution at a constant rate.

[0026] By adding the bis(fluorosulfonyl)imide heavy residue to an acidic aqueous solution and further limiting the feeding time to 0.5-3 h, it is beneficial to control the reaction rate, ensure the reaction proceeds fully, and further improve the safety of the treatment method provided in this application.

[0027] This application does not limit the specific type of acidic aqueous solution; any acidic aqueous solution capable of dissolving and dispersing the bis(fluorosulfonyl)imide heavy residue in the raw material system is acceptable.

[0028] Furthermore, the acidic aqueous solution is at least one of sulfuric acid aqueous solution, nitric acid aqueous solution, and hydrochloric acid aqueous solution.

[0029] The inventors discovered that when the acidic aqueous solution is selected from at least one of sulfuric acid aqueous solution, nitric acid aqueous solution and hydrochloric acid aqueous solution, it can promote the complete reaction of difluorosulfonylimide heavy residue. Furthermore, when the acidic aqueous solution is sulfuric acid aqueous solution, the safety of the treatment method can be further improved, the reaction process is more gentle, and the introduction of other impurities can be further avoided, and the generation of other by-products can be reduced.

[0030] Specifically, the mass percentage of acid in sulfuric acid aqueous solution is 50-98%, the mass percentage of acid in nitric acid aqueous solution is 40-68%, and the mass percentage of acid in hydrochloric acid aqueous solution is 20-37%.

[0031] It is understandable that using concentrated acid solutions is more conducive to the dissolution and dispersion of bis(fluorosulfonyl)imide heavy residue. When the mass percentage of acid in sulfuric acid aqueous solution is 50-98%, the mass percentage of acid in nitric acid aqueous solution is 40-68%, and the mass percentage of acid in hydrochloric acid aqueous solution is 20-37%, the reaction can be further promoted, and the generated hydrogen fluoride can be more easily dissolved, further reacting to generate fluorosulfonic acid.

[0032] Optionally, the mass ratio of the bis(fluorosulfonyl)imide heavy residue to the acidic aqueous solution is 1:(1-10). The inventors have discovered that when the mass ratio of the bis(fluorosulfonyl)imide heavy residue to the acidic aqueous solution is 1:(1-10), the reaction can be further promoted to proceed fully, ensuring complete reaction of the bis(fluorosulfonyl)imide heavy residue and further improving the resource utilization of the treatment method.

[0033] Furthermore, the mass ratio of the difluorosulfonamide heavy residue to the acidic aqueous solution is 1:(3-10).

[0034] In some specific embodiments, the reaction temperature is 30-100°C; further limiting the reaction temperature of the treatment method can further control the reaction rate and promote the reaction.

[0035] In some other specific embodiments, the reaction time is 1-10 hours. It is understood that reaction time is an important factor in chemical reactions. The inventors have found that when the reaction time is further limited to 1-10 hours, the extent of the reaction and the amount of product generated can be further controlled, which is more conducive to the resource utilization of difluorosulfonyl imide.

[0036] Optionally, the reaction is accompanied by stirring at a speed of 100-500 rpm; in order to promote mixing and diffusion among the reactants and to make the difluorosulfonyl imide more uniformly dispersed in the raw material system for reaction, the stirring speed can be further limited to 100-500 rpm.

[0037] Furthermore, the method for treating the bis(fluorosulfonyl)imide heavy residue also includes: rinsing the crude aminosulfonic acid product with an acidic washing solution to obtain the aminosulfonic acid product and the rinsed acid solution.

[0038] After the reaction is complete, a fluorinated acid solution and crude aminosulfonic acid are obtained. To further separate the products and better utilize them for resource recovery, the crude aminosulfonic acid can be leached with an acidic washing solution to remove residual fluorosulfonic acid, yielding the aminosulfonic acid product and the leached acid solution. The acidic washing solution used in the leaching process is used to remove residual fluoride ions from the crude aminosulfonic acid. The acidic washing solution can be selected from at least one of sulfuric acid aqueous solution, nitric acid aqueous solution, and hydrochloric acid aqueous solution. The mass percentage of acid in the sulfuric acid aqueous solution is 50-98%, the mass percentage of acid in the nitric acid aqueous solution is 40-68%, and the mass percentage of acid in the hydrochloric acid aqueous solution is 20-37%. The acidic washing solution used in the leaching process can be the same type as or different from the acidic aqueous solution used in the above reaction. When the acidic washing solution used in the leaching process is the same type as the acidic aqueous solution used in the above reaction, no other impurities will be introduced, which is beneficial for further recovery of fluoride from the leached acid solution.

[0039] Furthermore, the acidic washing solution is selected from an aqueous sulfuric acid solution, with an acid content of 70-98% by mass. Controlling the acid content in the aqueous sulfuric acid solution to 70-98% by mass, and keeping the water content low, can reduce the dissolution of aminosulfonic acid during the rinsing process and improve the recovery rate of sulfonamide heavy residue.

[0040] Specifically, after the reaction is complete, the mixture is filtered, and the solid-phase aminosulfonic acid filter cake is washed several times with an acidic aqueous solution to obtain aminosulfonic acid product and acid solution after washing. Optionally, the acid solution after washing can be detected by ion chromatography to determine whether the solid-phase aminosulfonic acid product contains fluorine. Through washing treatment, fluorine-free aminosulfonic acid product can be obtained, improving the recycling value of the product and facilitating better resource utilization of difluorosulfonylimide.

[0041] It is understood that aminosulfonic acid products contain a small amount of acidic washing liquid and impurities, so the mass fraction of aminosulfonic acid in aminosulfonic acid products is 70-95%. Therefore, it is possible to purify aminosulfonic acid products. This application does not limit the purification method of aminosulfonic acid products. This method is a commonly used method in the field and will not be described in detail here. Taking sulfuric acid aqueous solution as an example, it is possible to utilize the solubility characteristics of aminosulfonic acid itself to prepare a sulfuric acid solution with a concentration of 71.8% by dissolving fluorinated sulfuric acid. Based on the principle that the solubility of aminosulfonic acid in 71.8% sulfuric acid solution is '0', aminosulfonic acid is precipitated out to achieve the purpose of separation from sulfuric acid.

[0042] In some specific implementations, the rinsing treatment is performed 3-8 times.

[0043] In some other embodiments, during the rinsing process, the amount of acidic washing solution used is 1-5 times the mass of the difluorosulfonylimide heavy residue.

[0044] The process involves using an acidic washing solution for rinsing to remove fluorosulfonic acid from the aminosulfonic acid product. When the number of rinsing cycles is further limited to 3-8 times, and / or the amount of acidic washing solution used is 1-5 times the mass of the difluorosulfonylimide residue, fluorine in the difluorosulfonylimide can be further removed, resulting in fluorine-free aminosulfonic acid.

[0045] In some embodiments, the method further includes: using a fluorinated acid solution and / or the acid solution after rinsing as raw materials to prepare phosphorus pentafluoride. Since both the fluorinated acid solution obtained from the reaction and the acid solution after rinsing contain fluorine, they can be used as byproducts in the production of phosphorus pentafluoride, further improving the resource utilization of difluorosulfonylimide and reducing processing costs.

[0046] Example

[0047] The following detailed description of a method for treating bis(fluorosulfonyl)imide heavy slag provided by the present invention is provided through specific embodiments. Various tests and evaluations were conducted according to the methods described below. Furthermore, unless otherwise specified, "parts" and "%" refer to mass measurements.

[0048] Test methods and equipment:

[0049] Recovery test of bis(fluorosulfonyl)imide heavy residue

[0050] 1 g of bis(fluorosulfonyl)imide heavy residue was dissolved in a 100 mL volumetric flask, and diluted to volume with deionized water to obtain a bis(fluorosulfonyl)imide mother liquor. 1 mL of this mother liquor was then added to a 250 mL volumetric flask, and diluted to volume with deionized water to obtain a bis(fluorosulfonyl)imide heavy residue solution. The mass percentage of bis(fluorosulfonyl)imide anions in the bis(fluorosulfonyl)imide heavy residue was determined using an ion chromatograph (Metrophon 930 ion chromatograph, Switzerland). The mass of the bis(fluorosulfonyl)imide heavy residue to be tested was weighed using a balance, and the mass of bis(fluorosulfonyl)imide in the bis(fluorosulfonyl)imide heavy residue to be tested was calculated. The theoretical mass of bis(fluorosulfonyl)imide completely reacting to form aminosulfonic acid is A.

[0051] Dissolve 1g of aminosulfonic acid product in a 100mL volumetric flask, add deionized water to dilute to obtain aminosulfonic acid mother liquor, then take 1mL of the solution and dilute with deionized water to a 250mL volumetric flask to obtain aminosulfonic acid solution. Then, detect the mass percentage of aminosulfonate ions in the aminosulfonic acid solution using an ion chromatograph. Weigh the aminosulfonic acid product using a balance and calculate the mass B of aminosulfonic acid in the aminosulfonic acid product to be tested.

[0052] Recovery rate of bis(fluorosulfonyl)imide heavy residue = B / A × 100%.

[0053] Mass fraction testing of aminosulfonic acid products

[0054] Dissolve 1g of aminosulfonic acid product in a 100mL volumetric flask, add deionized water to dilute to obtain aminosulfonic acid mother liquor, then take 1mL of the solution and dilute with deionized water to a 250mL volumetric flask to obtain aminosulfonic acid solution. Then, detect the mass percentage of aminosulfonate in the aminosulfonic acid solution using an ion chromatograph. Weigh the mass of the aminosulfonic acid product to be tested using a balance, and calculate the mass of aminosulfonic acid in the aminosulfonic acid product, B.

[0055] The mass fraction of aminosulfonic acid products = B / M × 100%.

[0056] Example 1

[0057] (1) Add 300g of 95% sulfuric acid aqueous solution to a 500ml PTFE three-necked reaction flask, and then add 100g of bis(fluorosulfonyl)imide heavy residue to the same flask at the same rate for 2 hours. Then place the three-necked reaction flask in an 80℃ constant temperature magnetic stirrer and start stirring at 200rpm. The tail gas is absorbed by the alkaline solution. When the content of bis(fluorosulfonyl)imide anion in the raw material system is 0, the reaction is stopped. After filtration, a fluorinated acid solution and crude aminosulfonic acid are obtained.

[0058] (2) The crude aminosulfonic acid was rinsed three times with 100g of 95% sulfuric acid solution to obtain the aminosulfonic acid product and the acid solution after rinsing.

[0059] Example 2

[0060] The difference between this embodiment and Embodiment 1 is that the concentration of the sulfuric acid aqueous solution is 70%.

[0061] Example 3

[0062] The difference between this embodiment and Embodiment 1 is that the concentration of the sulfuric acid aqueous solution is 50%.

[0063] Example 4

[0064] The difference between this embodiment and Embodiment 1 is that the 95% sulfuric acid aqueous solution is replaced with a 40% nitric acid aqueous solution.

[0065] Example 5

[0066] The difference between this embodiment and Embodiment 1 is that the 95% sulfuric acid aqueous solution is replaced with a 55% nitric acid aqueous solution.

[0067] Example 6

[0068] The difference between this embodiment and Embodiment 1 is that the 95% sulfuric acid aqueous solution is replaced with a 68% nitric acid aqueous solution.

[0069] Example 7

[0070] The difference between this embodiment and Embodiment 1 is that the 95% sulfuric acid aqueous solution is replaced with a 20% hydrochloric acid aqueous solution.

[0071] Example 8

[0072] The difference between this embodiment and Embodiment 1 is that the 95% sulfuric acid aqueous solution is replaced with a 30% hydrochloric acid aqueous solution.

[0073] Example 9

[0074] The difference between this embodiment and Embodiment 1 is that the 95% sulfuric acid aqueous solution is replaced with a 37% hydrochloric acid aqueous solution.

[0075] Example 10

[0076] The difference between this embodiment and embodiment 1 is that in step (1), 100g of sulfuric acid aqueous solution is added.

[0077] Example 11

[0078] The difference between this embodiment and embodiment 1 is that in step (1), 500g of sulfuric acid aqueous solution is added.

[0079] Example 12

[0080] The difference between this embodiment and embodiment 1 is that in step (1), 800g of sulfuric acid aqueous solution is added.

[0081] Example 13

[0082] The difference between this embodiment and embodiment 1 is that in step (1), 1000g of sulfuric acid aqueous solution is added.

[0083] Example 14

[0084] The difference between this embodiment and embodiment 1 is that the reaction temperature in step (1) is 30°C.

[0085] Example 15

[0086] The difference between this embodiment and embodiment 1 is that the reaction temperature in step (1) is 70°C.

[0087] Example 16

[0088] The difference between this embodiment and embodiment 1 is that the reaction temperature in step (1) is 100°C.

[0089] Example 17

[0090] The difference between this embodiment and embodiment 1 is that in step (2), the number of rinses is 5.

[0091] Example 18

[0092] The difference between this embodiment and embodiment 1 is that in step (2), the number of rinses is 7.

[0093] Example 19

[0094] The difference between this embodiment and embodiment 1 is that in step (2), the number of rinses is 8.

[0095] Example 20

[0096] The difference between this embodiment and embodiment 1 is that in step (2), 300g of sulfuric acid aqueous solution is added during the rinsing process.

[0097] Example 21

[0098] The difference between this embodiment and embodiment 1 is that in step (2), 500g of sulfuric acid aqueous solution is added during the rinsing process.

[0099] Example 22

[0100] The difference between this embodiment and Embodiment 1 is that the concentration of the sulfuric acid aqueous solution is 45%.

[0101] Example 23

[0102] The difference between this embodiment and embodiment 1 is that the reaction temperature in step (1) is 20°C.

[0103] Example 24

[0104] The difference between this embodiment and embodiment 1 is that in step (2), the number of rinses is 1.

[0105] Example 25

[0106] The difference between this embodiment and embodiment 1 is that in step (2), 50g of sulfuric acid aqueous solution is added during the rinsing process.

[0107] Example 26

[0108] The difference between this embodiment and embodiment 1 is that step (2) is omitted.

[0109] Example 27

[0110] The difference between this embodiment and Example 1 is that the concentration of the sulfuric acid aqueous solution is 98%; in step (1), 500g of sulfuric acid aqueous solution is added, the reaction temperature is 90℃, and the reaction time is 1h; in step (2), the number of rinsing times is 3.

[0111] Example 28

[0112] The difference between this embodiment and Example 1 is that the concentration of the sulfuric acid aqueous solution is 90%; in step (1), 800g of sulfuric acid aqueous solution is added, the reaction temperature is 100℃, and the reaction time is 4h; in step (2), the number of rinsing times is 5.

[0113] Example 29

[0114] The difference between this embodiment and Example 1 is that the concentration of the sulfuric acid aqueous solution is 85%; in step (1), 1000g of sulfuric acid aqueous solution is added, the reaction temperature is 90℃, and the reaction time is 6h; in step (2), the number of rinsing times is 7.

[0115] Example 30

[0116] The difference between this embodiment and Example 1 is that the concentration of the sulfuric acid aqueous solution is 80%; in step (1), 1000g of sulfuric acid aqueous solution is added, the reaction temperature is 90℃, and the reaction time is 10h; in step (2), the number of rinsing times is 5.

[0117] Example 31

[0118] The difference between this embodiment and Example 1 is that the concentration of the sulfuric acid aqueous solution is 70%; in step (1), 600g of sulfuric acid aqueous solution is added, the reaction temperature is 70℃, and the reaction time is 2h; in step (2), the number of rinsing times is 5.

[0119] Example 32

[0120] The difference between this embodiment and Example 1 is that the concentration of the sulfuric acid aqueous solution is 60%; in step (1), 400g of sulfuric acid aqueous solution is added, the reaction temperature is 80℃, and the reaction time is 3h; in step (2), the number of rinsing times is 5.

[0121] Example 33

[0122] The difference between this embodiment and Example 1 is that the concentration of the sulfuric acid aqueous solution is 50%; in step (1), 300g of sulfuric acid aqueous solution is added, the reaction temperature is 60℃, and the reaction time is 5h; in step (2), the number of rinsing times is 5.

[0123] Example 34

[0124] The difference between this embodiment and Embodiment 1 is that the reaction temperature is 120℃.

[0125] The experimental parameters and results in the above embodiments are shown in Table 1; wherein, the amount of acidic aqueous solution used is a multiple of the mass of acidic aqueous solution and difluorosulfonyl imide heavy residue; the concentration of acidic aqueous solution represents the mass percentage content of acid in acidic aqueous solution and acidic washing solution; since aminosulfonic acid products may contain a small amount of acidic aqueous solution and impurities, the mass fraction of aminosulfonic acid products represents the mass percentage content of aminosulfonic acid in them.

[0126] Table 1

[0127] As shown in the table, the method for treating bis(fluorosulfonyl)imide heavy residue provided in this application can obtain a fluorinated acid solution and crude aminosulfonic acid by reacting a raw material system including bis(fluorosulfonyl)imide heavy residue and an acidic aqueous solution. The fluorinated acid solution can be used as a by-product acid, and the aminosulfonic acid product can be directly sold as a finished product, reducing processing costs and realizing the resource-based recycling of the bis(fluorosulfonyl)imide heavy residue. Specifically, the reaction time can be controlled by adjusting factors such as the concentration and amount of the acidic aqueous solution and the reaction time to improve the processing effect, or the requirements for reaction time and product purity can be reduced to decrease the amount of raw materials used and the energy consumption of the reaction.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for treating bis(fluorosulfonyl)imide heavy residue, characterized in that, Includes the following steps: The raw material system, consisting of bis(fluorosulfonyl)imide heavy residue and acidic aqueous solution, is reacted to obtain a fluorinated acid solution and crude aminosulfonic acid.

2. The processing method according to claim 1, characterized in that, The bis(fluorosulfonyl)imide heavy residue is added to the acidic aqueous solution to carry out the reaction, and the addition time is 0.5-3 hours.

3. The processing method according to claim 1 or 2, characterized in that, The acidic aqueous solution is at least one of sulfuric acid aqueous solution, nitric acid aqueous solution and hydrochloric acid aqueous solution.

4. The processing method according to any one of claims 1-3, characterized in that, The sulfuric acid aqueous solution contains 50-98% acid by mass, the nitric acid aqueous solution contains 40-68% acid by mass, and the hydrochloric acid aqueous solution contains 20-37% acid by mass.

5. The processing method according to any one of claims 1-4, characterized in that, The mass ratio of the bis(fluorosulfonyl)imide heavy residue to the acidic aqueous solution is 1:(1-10), preferably 1:(3-10).

6. The processing method according to any one of claims 1-5, characterized in that, The reaction temperature is 30-100℃; and / or, The reaction time is 1-10 hours.

7. The processing method according to any one of claims 1-6, characterized in that, The reaction is accompanied by stirring at a speed of 100-500 rpm.

8. The processing method according to any one of claims 1-7, characterized in that, Also includes: The crude aminosulfonic acid was leached with an acidic washing solution to obtain the aminosulfonic acid product and the acidic solution after leaching. The acidic washing solution is selected from at least one of sulfuric acid aqueous solution, nitric acid aqueous solution and hydrochloric acid aqueous solution.

9. The processing method according to claim 8, characterized in that, The rinsing treatment is performed 3-8 times; and / or, In the rinsing process, the amount of acidic washing solution used is 1-5 times the mass of the difluorosulfonyl imide heavy slag.

10. The processing method according to claim 8 or 9, characterized in that, Also includes: Phosphorus pentafluoride is prepared using the fluorinated acid solution and / or the acid solution after rinsing as raw materials.

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