Treatment method of bis (fluorosulfonyl) imide heavy slag

Abstract

The invention provides a method for treating bis (fluorosulfonyl) imide heavy slag, which comprises the following steps: reacting a raw material system comprising bis (fluorosulfonyl) imide heavy slag and an acidic aqueous solution to obtain a fluorine-containing acid solution and a sulfamic acid crude product; wherein the fluorine-containing acid liquid can be used as a byproduct acid, so that the treatment cost is saved; and the sulfamic acid crude product can also be directly sold as a product, so that the treatment cost is reduced, economic benefits are brought, and resource recycling of the bis (fluorosulfonyl) imide heavy slag is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bisfluorosulfonylimide heavy residue recovery, and particularly relates to a bisfluorosulfonylimide heavy residue treatment method. BACKGROUND

[0002] Bisfluorosulfonylimide is widely used in lithium ion batteries as a raw material for preparing lithium bisfluorosulfonylimide. Bisfluorosulfonylimide is obtained by impurity removal method, and the purification process produces bisfluorosulfonylimide heavy residue. The bisfluorosulfonylimide heavy residue is a viscous liquid with poor flowability, and its main components are bisfluorosulfonylimide and fluorosulfonic acid and a small amount of salt, wherein the proportion of bisfluorosulfonylimide and fluorosulfonic acid is more than 95%. With the increasing demand for lithium bisfluorosulfonylimide in the market, the production of bisfluorosulfonylimide lithium by enterprises is increasing, which will produce more bisfluorosulfonylimide heavy residue.

[0003] Therefore, it is urgent to develop a bisfluorosulfonylimide heavy residue treatment method to realize the recycling and utilization of heavy residue. SUMMARY

[0004] The application provides a bisfluorosulfonylimide heavy residue treatment method, which can realize the recycling and utilization of heavy residue and reduce the treatment cost.

[0005] The application provides a bisfluorosulfonylimide heavy residue treatment method, which comprises the following steps:

[0006] The raw material system comprising bisfluorosulfonylimide heavy residue and an acidic aqueous solution is reacted to obtain fluorine-containing acid liquid and aminosulfonic acid crude product.

[0007] Further, the bisfluorosulfonylimide heavy residue is added to the acidic aqueous solution for the reaction, and the feeding time is 0.5-3h.

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

[0009] Further, the mass percentage content of acid in the acidic aqueous solution is 50-98%.

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

[0011] Further, the reaction temperature of the reaction is 30-100℃; and / or,

[0012] The reaction time of the reaction is 1-10h.

[0013] Further, stirring is accompanied in the reaction process, and the stirring speed is 100-500rpm.

[0014] Further, it also comprises:

[0015] The acid washing liquid is used for elution treatment of the sulfamic acid crude product, so as to obtain sulfamic acid product and eluted acid liquid.

[0016] Further, the elution treatment is performed for 3-8 times; and / or,

[0017] In the elution treatment, the amount of the acid washing liquid is 1-5 times of the mass of the bisfluorosulfonylimine heavy residue.

[0018] Further, it also comprises: at least one of the fluorine-containing acid liquid and the eluted acid liquid is used as raw material for preparation of phosphorus pentafluoride.

[0019] The application provides a treatment method of bisfluorosulfonylimine heavy residue, which comprises the following steps: reacting a raw material system comprising bisfluorosulfonylimine heavy residue and an acidic aqueous solution to obtain a fluorine-containing acid liquid and a sulfamic acid crude product; wherein the fluorine-containing acid liquid can be used as by-product acid to save treatment cost; and the sulfamic acid crude product can be directly sold as product to reduce treatment cost and bring economic benefits, and resource recycling of the bisfluorosulfonylimine heavy residue is realized. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions and advantages of the present application clearer, the following will be a clear and complete description of the technical solutions in the embodiments of the present application in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] In one aspect, the present application provides a treatment method of bisfluorosulfonylimine heavy residue, comprising the following steps:

[0022] Reacting a raw material system comprising bisfluorosulfonylimine heavy residue and an acidic aqueous solution to obtain a fluorine-containing acid liquid and a sulfamic acid crude product.

[0023] The bisfluorosulfonylimine heavy residue in the present application refers to heavy residue produced in the process of removing impurities and purifying bisfluorosulfonylimine raw material during preparation of bisfluorosulfonylimine raw material, and the main components of the heavy residue are bisfluorosulfonylimine and trace amounts of salts thereof, and fluorosulfonic acid and trace amounts of salts thereof; the proportion of bisfluorosulfonylimine and fluorosulfonic acid in the bisfluorosulfonylimine heavy residue is more than 95%; the bisfluorosulfonylimine heavy residue is a viscous liquid with extremely poor fluidity, and there is no method for resource utilization of bisfluorosulfonylimine in the prior art.

[0024] The present application can generate fluorosulfonic acid, aminosulfonic acid and hydrogen fluoride by reacting a raw material system comprising difluorosulfonylimide heavy residue and an acidic aqueous solution, and the reaction principle is shown in formula 1:

[0025]

[0026] Specifically, the acidic aqueous solution dissolves the difluorosulfonylimide heavy residue, disperses it in the acidic aqueous solution, and fully reacts with water in the acidic aqueous solution; wherein the obtained fluorosulfonic acid is in liquid phase and directly dissolves in the acidic aqueous solution; the generated hydrogen fluoride further dissolves in the acidic aqueous solution to generate acid, and a small amount of hydrogen fluoride may overflow the system, and the hydrogen fluoride tail gas can be optionally introduced into lye for treatment; and the generated aminosulfonic acid is in solid phase and forms a precipitate in the raw material system, which can be separated from the liquid by filtration.

[0027] The present application provides a treatment method for difluorosulfonylimide heavy residue, which reacts a raw material system comprising difluorosulfonylimide heavy residue and an acidic aqueous solution to obtain fluorine-containing acid liquid and aminosulfonic acid crude product; wherein the fluorine-containing acid liquid can be used as a by-product acid to save treatment costs; and the aminosulfonic acid crude product can also be directly sold as a product to reduce treatment costs and bring economic benefits, realizing the resource recycling of difluorosulfonylimide heavy residue.

[0028] Further, the raw material system can be tested by ion chromatography, and when the anion content of difluorosulfonylimide in the raw material system is 0, it can be judged that the reaction is complete, at which time the difluorosulfonylimide has been completely converted.

[0029] The difluorosulfonylimide heavy residue is added to the acidic aqueous solution for the above reaction, and the feeding time is 0.5-3h.

[0030] By adding the difluorosulfonylimide heavy residue to the acidic aqueous solution, and further limiting the feeding time to 0.5-3h, the reaction rate can be controlled, the reaction can be fully carried out, and the safety of the treatment method provided by the present application can be further improved.

[0031] The present application does not limit the specific type of the acidic aqueous solution, and any acidic aqueous solution that can dissolve and disperse the difluorosulfonylimide heavy residue in the raw material system can be used.

[0032] Further, the acidic aqueous solution is at least one of sulfuric acid aqueous solution, nitric acid aqueous solution and hydrochloric acid aqueous solution.

[0033] The inventors find that when the acidic aqueous solution is a sulfuric acid aqueous solution, a nitric acid aqueous solution, and a hydrochloric acid aqueous solution, the complete reaction of the bisfluorosulfonylimide heavy residue can be promoted. Further, when the acidic aqueous solution is a 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.

[0034] Specifically, the mass percentage content of the acid in the acidic aqueous solution is 50-98%.

[0035] It can be understood that the use of a concentrated acid solution is more conducive to the dissolution and dispersion of the bisfluorosulfonylimide heavy residue. When the mass percentage content of the acid in the acidic aqueous solution is 50-98%, the reaction can be further promoted, and the generated hydrogen fluoride can be more conducive to dissolving to generate fluorosulfonic acid.

[0036] Optionally, the mass ratio of the bisfluorosulfonylimide heavy residue to the acidic aqueous solution is 1:(1-10).

[0037] The mass ratio of the bisfluorosulfonylimide heavy residue to the acidic aqueous solution is an important influencing factor of the reaction. The inventors find that when the mass ratio of the bisfluorosulfonylimide heavy residue to the acidic aqueous solution is 1:(1-10), the reaction can be further promoted to proceed fully, the bisfluorosulfonylimide heavy residue can be completely reacted, and the resource utilization of the treatment method can be further improved.

[0038] In a specific embodiment, the reaction temperature of the reaction is 30-100°C.

[0039] The reaction temperature of the reaction is further limited for the treatment method, which can further control the reaction rate and promote the reaction.

[0040] In another specific embodiment, the reaction time of the reaction is 1-10h.

[0041] It can be understood that the reaction time is an important factor of a chemical reaction. The inventors find that when the reaction time is further limited to 1-10h, the degree of reaction and the amount of product generated can be further controlled, and the resource utilization of the bisfluorosulfonylimide can be more conducive.

[0042] Optionally, stirring is accompanied in the reaction, and the stirring speed is 100-500rpm.

[0043] In order to promote the mixing and diffusion between the reactants and to make the bisfluorosulfonylimide more uniformly dispersed in the raw material system for reaction, the stirring speed can be further limited to 100-500rpm.

[0044] Further, it further comprises:

[0045] The acid washing liquid is used to elute the ammonium sulfamate crude product to obtain the ammonium sulfamate product and the eluted acid liquid.

[0046] When the reaction is completed, a fluorine-containing acid solution and a crude aminosulfonic acid are obtained. In order to further separate the product and better resource utilization, the crude aminosulfonic acid can be subjected to elution treatment with an acidic washing solution to remove residual fluorosulfonic acid in the crude aminosulfonic acid, so as to obtain an aminosulfonic acid product and an eluted acid solution;

[0047] In the elution treatment, the acidic washing solution is used to remove residual fluorine ions in the crude aminosulfonic acid. The acidic washing solution can be at least one of a sulfuric acid aqueous solution, a nitric acid aqueous solution and a hydrochloric acid aqueous solution. The acidic washing solution used in the elution treatment and the acidic aqueous solution in the above reaction can be of the same type or different types. When the acidic washing solution used in the elution treatment and the acidic aqueous solution in the above reaction are of the same type, no other impurities are further introduced, which is conducive to further recovery of fluorine in the eluted acid solution.

[0048] Specifically, after the reaction is completed, the mixture is filtered, and the solid-phase aminosulfonic acid filter cake is subjected to elution treatment with an acidic aqueous solution for several times to obtain an aminosulfonic acid product and an eluted acid solution. Optionally, the eluted acid solution is detected by ion chromatography to determine whether the solid-phase aminosulfonic acid product contains fluorine. Through the elution treatment, a fluorine-free aminosulfonic acid product can be further obtained, which improves the recycling value of the product and is conducive to better resource utilization of bisfluorosulfonylimide.

[0049] It can be understood that the aminosulfonic acid product contains a small amount of the acidic washing solution and impurities, and therefore the mass fraction of aminosulfonic acid in the aminosulfonic acid product is 70-95%. Therefore, the aminosulfonic acid product can be selected for purification. The purification method of the aminosulfonic acid product is not limited in the present application, which is a commonly used method in the art and will not be described here. Taking the sulfuric acid as an example, the fluorine-containing sulfuric acid can be prepared into a 71.8% sulfuric acid solution by using the solubility characteristics of aminosulfonic acid itself. According to the principle that the solubility of aminosulfonic acid in the 71.8% sulfuric acid solution is '0', the aminosulfonic acid is precipitated and separated from the sulfuric acid.

[0050] In a specific embodiment, the elution treatment is performed for 3-8 times.

[0051] In another specific embodiment, in the elution treatment, the amount of the acidic washing solution is 1-5 times the mass of the bisfluorosulfonylimide heavy residue.

[0052] In the elution treatment, the acidic washing solution is used to remove fluorosulfonic acid in the aminosulfonic acid product. When the elution treatment is performed for 3-8 times and / or the amount of the acidic washing solution is 1-5 times the mass of the bisfluorosulfonylimide heavy residue, fluorine in the bisfluorosulfonylimide can be further removed, and fluorine-free aminosulfonic acid can be obtained.

[0053] In an embodiment, the method further comprises: using at least one of the fluorine-containing acid solution and the eluted acid solution as raw material to participate in the preparation of phosphorus pentafluoride.

[0054] Since the fluorine-containing acid solution obtained by the reaction and the eluted acid solution obtained by the elution treatment both contain fluorine, the fluorine-containing acid solution and the eluted acid solution can be used as by-products in the production of phosphorus pentafluoride, further improving the resource utilization of the bisfluorosulfonylimide and reducing the treatment cost.

[0055] Hereinafter, a method for treating bisfluorosulfonylimide heavy residues provided by the present application is described in detail through specific embodiments.

[0056] Embodiment 1

[0057] (1) 300 g of a 95% sulfuric acid aqueous solution was added to a 500 ml PTFE three-necked reaction bottle, and then 100 g of bisfluorosulfonylimide heavy residues was added to the three-necked reaction bottle at the same speed, and the three-necked reaction bottle was placed in a constant-temperature magnetic stirring kettle at 80°C, and stirring was started, the stirring speed was 200 rpm, the tail gas was connected to a lye absorption device, and when the anion content in the raw material system was 0, the reaction was stopped; after filtration, a fluorine-containing acid solution and a crude aminosulfonic acid were obtained.

[0058] (2) The crude aminosulfonic acid was washed with 100 g of a 95% sulfuric acid washing solution for three times to obtain an aminosulfonic acid product and an eluted acid solution.

[0059] Embodiment 2

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

[0061] Embodiment 3

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

[0063] Embodiment 4

[0064] The difference between this embodiment and Embodiment 1 is that in step (1), 500 g of a sulfuric acid aqueous solution is added.

[0065] Embodiment 5

[0066] The difference between this embodiment and Embodiment 1 is that in step (1), 800 g of a sulfuric acid aqueous solution is added.

[0067] Embodiment 6

[0068] The difference between this embodiment and Embodiment 1 is that in step (1), 1000 g of a sulfuric acid aqueous solution is added.

[0069] Embodiment 7

[0070] The difference between this example and Example 1 is that in step (1), the reaction temperature is 30°C.

[0071] Example 8

[0072] The difference between this example and Example 1 is that in step (1), the reaction temperature is 70°C.

[0073] Example 9

[0074] The difference between this example and Example 1 is that in step (1), the reaction temperature is 100°C.

[0075] Example 10

[0076] The difference between this example and Example 1 is that in step (2), the number of washing times is 5.

[0077] Example 11

[0078] The difference between this example and Example 1 is that in step (2), the number of washing times is 7.

[0079] Example 12

[0080] The difference between this example and Example 1 is that in step (2), the number of washing times is 8.

[0081] Example 13

[0082] The difference between this example and Example 1 is that in step (2), 300 g of sulfuric acid washing solution is added in the washing process.

[0083] Example 14

[0084] The difference between this example and Example 1 is that in step (2), 500 g of sulfuric acid washing solution is added in the washing process.

[0085] Example 15

[0086] The difference between this example and Example 1 is that the concentration of the aqueous sulfuric acid solution is 45%.

[0087] Example 16

[0088] The difference between this example and Example 1 is that in step (1), 50 g of aqueous sulfuric acid solution is added.

[0089] Example 17

[0090] The difference between this example and Example 1 is that in step (1), the reaction temperature is 20°C.

[0091] Example 18

[0092] The difference between this example and Example 1 is that in step (2), the number of times of elution is 6.

[0093] Example 19

[0094] The difference between this example and Example 1 is that in step (2), 50 g of sulfuric acid washing solution is added in the elution treatment.

[0095] Example 20

[0096] The difference between this example and Example 1 is that both the acidic aqueous solution and the acidic washing solution are nitric acid aqueous solution with a concentration of 95%.

[0097] Example 21

[0098] The difference between this example and Example 1 is that step (2) is not performed.

[0099] Example 22

[0100] The difference between this example and Example 1 is that the concentration of the sulfuric acid aqueous solution is 98%; in step (1), 500 g of sulfuric acid aqueous solution is added, the reaction temperature is 90°C, and the reaction time is 1 h; in step (2), the number of times of elution is 1.

[0101] Example 23

[0102] The difference between this example and Example 1 is that the concentration of the sulfuric acid aqueous solution is 90%; in step (1), 800 g of sulfuric acid aqueous solution is added, the reaction temperature is 100°C, and the reaction time is 4 h; in step (2), the number of times of elution is 3.

[0103] Example 24

[0104] The difference between this example and Example 1 is that the concentration of the sulfuric acid aqueous solution is 85%; in step (1), 1000 g of sulfuric acid aqueous solution is added, the reaction temperature is 90°C, and the reaction time is 6 h; in step (2), the number of times of elution is 5.

[0105] Example 25

[0106] The difference between this example and Example 1 is that the concentration of the sulfuric acid aqueous solution is 80%; in step (1), 1000 g of sulfuric acid aqueous solution is added, the reaction temperature is 90°C, and the reaction time is 10 h; in step (2), the number of times of elution is 2.

[0107] Example 26

[0108] The difference between this example and Example 1 is that the concentration of the sulfuric acid aqueous solution is 70%; in step (1), 600 g of sulfuric acid aqueous solution is added, the reaction temperature is 70°C, and the reaction time is 2 h; in step (2), the number of times of elution is 2.

[0109] Example 27

[0110] The difference between this example and Example 1 is that the concentration of the aqueous sulfuric acid solution is 60%; in step (1), 400 g of the aqueous sulfuric acid solution is added, the reaction temperature is 80°C, and the reaction time is 3 h; in step (2), the number of elution times is 2.

[0111] Example 28

[0112] The difference between this example and Example 1 is that the concentration of the aqueous sulfuric acid solution is 50%; in step (1), 300 g of the aqueous sulfuric acid solution is added, the reaction temperature is 60°C, and the reaction time is 5 h; in step (2), the number of elution times is 2.

[0113] Example 29

[0114] The difference between this example and Example 1 is that the reaction temperature is 120°C.

[0115] Test Example 1

[0116] The content of the difluorosulfone imide anion in the difluorosulfone imide heavy residue is detected by an ion chromatograph to obtain the content of the difluorosulfone imide, and then the content of the sulfamic acid root in the sulfamic acid product obtained in the above examples is detected by the ion chromatograph. The recovery rate of the difluorosulfone imide heavy residue is calculated by comparing the theoretical amount of the sulfamic acid that completely reacts with the difluorosulfone imide;

[0117] The content of the sulfamic acid root in the sulfamic acid product is detected by an ion chromatograph to calculate the mass fraction of the sulfamic acid product. The experimental parameters and results in the above examples are shown in Table 1.

[0118] The amount of the aqueous acid solution is the multiple of the mass of the aqueous acid solution and the difluorosulfone imide heavy residue; the concentration of the aqueous acid solution represents the mass percentage of the acid in the aqueous acid solution and the acid washing solution; since the sulfamic acid product contains a small amount of the aqueous acid solution and impurities, the mass fraction of the sulfamic acid product represents the mass percentage of the sulfamic acid therein.

[0119] Table 1

[0120]

[0121]

[0122] As shown in the table, the double fluorosulfurylimine heavy residue processing method provided by the application can obtain fluorine-containing acid liquid as by-product acid, and the aminosulfonic acid product can be directly sold as a product, thereby reducing the processing cost and realizing the recycling and utilization of the double fluorosulfurylimine heavy residue; specifically, the reaction time can be controlled by adjusting the concentration, dosage and reaction time of the acidic aqueous solution and other factors, the processing effect is improved, or the reaction time and product purity requirements are reduced to reduce the raw material dosage and reaction energy consumption.

[0123] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, but not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A method for treating a bisfluorosulfone imine heavy residue, characterized by, The method comprises the following steps: reacting a raw material system comprising a bisfluorosulfonylimide heavy residue and an acidic aqueous solution to obtain a fluorine-containing acid liquor and a crude aminosulfonic acid.

2. The treatment method according to claim 1, characterized in that, The bisfluorosulfonylimide heavy residue is added to the acidic aqueous solution for the reaction, and the feeding time is 0.5-3h.

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

4. The treatment method according to any one of claims 1 to 3, characterized in that, The mass percentage of acid in the acidic aqueous solution is 50-98%.

5. The treatment method according to any one of claims 1 to 4, characterized in that, The mass ratio of the bisfluorosulfonylimide heavy residue to the acidic aqueous solution is 1:(1-10).

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

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

8. The treatment method according to any one of claims 1 to 7, characterized in that, Further comprising: The crude aminosulfonic acid is subjected to elution treatment with an acidic washing solution to obtain an aminosulfonic acid product and an eluted acid liquor.

9. The treatment method according to claim 8, characterized in that, The elution treatment is performed for 3-8 times; and / or, In the elution treatment, the amount of the acidic washing solution is 1-5 times the mass of the bisfluorosulfonylimide heavy residue.

10. The treatment method according to claim 8 or 9, characterized in that, Further comprising: At least one of the fluorine-containing acid liquor and the eluted acid liquor is used as a raw material for the preparation of phosphorus pentafluoride.

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