Integrated process for the treatment of ammonium fluorosulfate by-product of bis(fluorosulfonyl)imide production

Abstract

This invention discloses a method for treating ammonium fluorosulfate byproducts, comprising providing an ammonium fluorosulfate byproduct mainly comprising ammonium fluorosulfate and a small amount of fluorosulfonic acid and bis(fluorosulfonyl)imide; mixing the ammonium fluorosulfate byproducts with water; reacting the mixture of ammonium fluorosulfate byproducts and water at a hydrolysis reaction temperature to hydrolyze the ammonium fluorosulfate, fluorosulfonic acid and bis(fluorosulfonyl)imide to form an aqueous solution of ammonium bisulfate and hydrogen fluoride; and separating the ammonium bisulfate from the aqueous solution of hydrogen fluoride.

Description

[0001] This application is a divisional application of the invention application with application number "202280008255.5" and invention title "Integrated method for treating ammonium fluorosulfate byproducts in the production of bis(fluorosulfonyl)imide".

[0002] Cross-references to related applications This patent application claims priority to U.S. Patent Application No. 17 / 554,977, filed December 17, 2021, and U.S. Provisional Patent Application No. 63 / 134,883, filed January 7, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a method for treating ammonium fluorosulfate byproducts. Specifically, this disclosure relates to an integrated method for treating ammonium fluorosulfate byproducts produced from bis(fluorosulfonyl)imide. Background Technology

[0004] Di(fluorosulfonyl)imide (HFSI) is a key raw material for producing lithium bis(fluorosulfonyl)imide (LiFSI) used in lithium-ion batteries. HFSI (HN(SO2F)2) can be prepared by several methods. For example, HFSI can be prepared by reacting urea (CO(NH2)2) with fluorosulfonic acid (HSO3F), as shown in Formula 1: Formula 1 5 HSO3F+2 CO(NH2)2→ HN(SO2F)2+2 CO2+3 NH4SO3F.

[0005] U.S. Patent 8,337,797 to Honda et al. discloses a two-step batch process for the production of HFSI from urea and fluosulfonic acid. In the first step, urea is dissolved in fluosulfonic acid at a temperature sufficiently low to prevent a reaction between urea and fluosulfonic acid as described in Formula 1. In the second step, a urea / fluosulfonic acid solution is slowly added to a separate reaction vessel containing a reaction medium that is sufficiently heated for the reaction described in Formula 1. The batch process disclosed in US 8,337,797 is insufficient for efficient commercial-scale production of HFSI.

[0006] International Publication WO 2011 / 111780, also granted to Honda et al., discloses a recovery method for continuously removing reaction liquids from a reaction vessel, such as by continuously discharging reaction liquids (containing ammonium fluorosulfate byproducts) in a slurry state through an overflow outlet. The disclosed method is carried out in a production batch, wherein the product HFSI is added back to the reaction vessel before being used in the next production batch.

[0007] Therefore, there is a need to develop a more efficient method that can be scaled up to produce commercial-volume HFSI. Summary of the Invention

[0008] This disclosure provides an integrated method for treating ammonium fluorosulfate that is generated as a byproduct in the production of bis(fluorosulfonyl)imide.

[0009] In one embodiment, the present invention provides a method for treating ammonium fluorosulfate byproducts. The method includes providing an ammonium fluorosulfate byproduct comprising primarily ammonium fluorosulfate and smaller amounts of fluorosulfonic acid and bis(fluorosulfonyl)imide; mixing the ammonium fluorosulfate byproduct with water; reacting the mixture of the ammonium fluorosulfate byproduct and water at a hydrolysis reaction temperature to hydrolyze the ammonium fluorosulfate, fluorosulfonic acid, and bis(fluorosulfonyl)imide to form an aqueous solution of ammonium bisulfate and hydrogen fluoride; and separating the ammonium bisulfate from the aqueous solution of hydrogen fluoride.

[0010] In another embodiment, the present invention provides a method for treating ammonium fluorosulfate byproducts. The method includes providing an ammonium fluorosulfate byproduct comprising primarily ammonium fluorosulfate and smaller amounts of fluorosulfonic acid and bis(fluorosulfonyl)imide; mixing the ammonium fluorosulfate byproduct with water and an alkali; and reacting the mixture of the ammonium fluorosulfate byproduct with water and alkali at a hydrolysis reaction temperature to hydrolyze and neutralize the ammonium fluorosulfate, fluorosulfonic acid, and bis(fluorosulfonyl)imide, forming a mixture comprising fluoride, sulfate, and ammonium bisulfate.

[0011] This application discloses the following technical solutions: Option 1. A method for treating ammonium fluorosulfate byproducts, the method comprising: It provides ammonium fluorosulfate byproducts that mainly contain ammonium fluorosulfate and smaller amounts of fluorosulfonic acid and bis(fluorosulfonyl)imide; The ammonium fluorosulfate byproduct is mixed with water; The mixture of the ammonium fluorosulfate byproduct and the water is reacted at a hydrolysis reaction temperature to hydrolyze the ammonium fluorosulfate, the fluorosulfonic acid, and the bis(fluorosulfonyl)imide to form an aqueous solution of ammonium bisulfate and hydrogen fluoride; and The ammonium bisulfate is separated from the aqueous solution of hydrogen fluoride.

[0012] Option 2. The method according to Option 1 further includes separating the water from the aqueous hydrogen fluoride solution to form concentrated hydrogen fluoride.

[0013] Option 3. The method according to Option 2, wherein separating the water from the aqueous hydrogen fluoride solution to form concentrated hydrogen fluoride comprises pressure swing distillation.

[0014] Option 4. The method according to Option 2 or Option 3, wherein the concentrated hydrogen fluoride is anhydrous hydrogen fluoride.

[0015] Option 5. The method according to any one of Options 1-4, wherein the concentration of ammonium fluorosulfate in the ammonium fluorosulfate byproduct is from 50% by weight to 99.9% by weight of the ammonium fluorosulfate byproduct.

[0016] Option 6. The method according to any one of Options 1-5, wherein the method is an integrated method further comprising the following steps: A solution containing fluorosulfonic acid and urea is provided; The solution containing fluorosulfonic acid and urea is reacted at a reaction temperature of about 80°C to about 170°C to produce a crude product containing bis(fluorosulfonyl)imide, fluorosulfonic acid and ammonium fluorosulfate. The ammonium fluorosulfate is separated from the crude product to produce an intermediate product having a higher concentration of bis(fluorosulfonyl)imide than the crude product and the ammonium fluorosulfate byproduct having a higher concentration of ammonium fluorosulfate than the crude product; and The intermediate product is separated into a concentrated product and a recycled product, wherein the concentrated product contains a higher concentration of bis(fluorosulfonyl)imide than the recycled product.

[0017] Option 7. A method for treating ammonium fluorosulfate byproducts, the method comprising: It provides ammonium fluorosulfate byproducts that mainly contain ammonium fluorosulfate and smaller amounts of fluorosulfonic acid and bis(fluorosulfonyl)imide; The ammonium fluorosulfate byproduct is mixed with water and alkali; and The ammonium fluorosulfate byproduct is reacted with the mixture of water and the alkali at a hydrolysis reaction temperature to hydrolyze and neutralize the ammonium fluorosulfate, the fluorosulfonic acid, and the bis(fluorosulfonyl)imide, forming a mixture containing fluoride, sulfate, and ammonium bisulfate.

[0018] Option 8. The method according to Option 7, wherein reacting the ammonium fluorosulfate byproduct with the mixture of the water and the base further forms ammonia.

[0019] Option 9. The method according to Option 7 or Option 8, wherein the base comprises calcium hydroxide, the formed fluoride comprises calcium fluoride, and the formed sulfate comprises calcium sulfate.

[0020] Option 10. The method according to Option 7 or Option 8, wherein the base comprises sodium hydroxide, the formed fluoride comprises sodium fluoride, and the formed sulfate comprises sodium sulfate.

[0021] Option 11. The method according to Option 7 or Option 8, wherein the base comprises potassium hydroxide, the formed fluoride comprises potassium fluoride, and the formed sulfate comprises potassium sulfate.

[0022] Option 12. The method according to Option 7 or Option 8, wherein the base comprises ammonium hydroxide, the formed fluoride comprises ammonium fluoride, and the formed sulfate comprises ammonium sulfate.

[0023] Scheme 13. The method according to any one of Schemes 7-12, wherein the ammonium fluorosulfate byproduct is substantially composed of ammonium fluorosulfate, fluorosulfonic acid and bis(fluorosulfonyl)imide.

[0024] Option 14. The method according to any one of Options 7-13, wherein the method is an integrated method further comprising the following steps: A solution containing fluorosulfonic acid and urea is provided; The solution containing fluorosulfonic acid and urea is reacted at a reaction temperature of about 80°C to about 170°C to produce a crude product containing bis(fluorosulfonyl)imide, fluorosulfonic acid and ammonium fluorosulfate. The ammonium fluorosulfate is separated from the crude product to produce an intermediate product having a higher concentration of bis(fluorosulfonyl)imide than the crude product and the ammonium fluorosulfate byproduct having a higher concentration of ammonium fluorosulfate than the crude product; and The intermediate product is separated into a concentrated product and a recycled product, wherein the concentrated product contains a higher concentration of bis(fluorosulfonyl)imide than the recycled product.

[0025] The above and other features of this disclosure, and the ways in which they are implemented, will become more apparent and better understood by referring to the following description of the embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0026] Figure 1 This is a process flow diagram showing an integrated method for the continuous treatment of ammonium fluorosulfate byproducts formed in the production of bis(fluorosulfonyl)imide, according to some embodiments of the present disclosure.

[0027] Figure 2 This is a process flow diagram showing another integrated method for the continuous treatment of ammonium fluorosulfate byproducts formed in the production of bis(fluorosulfonyl)imide, according to some embodiments of the present disclosure. Detailed Implementation

[0028] This disclosure provides an integrated method that can be scaled up to process the ammonium fluorosulfate byproduct formed in the commercial production of bis(fluorosulfonyl)imide (HFSI). HFSI can be produced by the reaction of urea with fluorosulfonic acid (FSA), as described above in Formula 1. The ammonium fluorosulfate byproduct formed in such production of HFSI mainly comprises ammonium fluorosulfate (NH4SO3F) and smaller amounts of HFSI and FSA. After concentrating HFSI, the resulting ammonium fluorosulfate byproduct is typically a solid, but can also be in slurry form of ammonium fluorosulfate and residual HFSI and FSA. The ammonium fluorosulfate byproduct is a potentially hazardous material due to its water reactivity, producing hydrofluoric acid. The disposal of the hazardous ammonium fluorosulfate byproduct can be dangerous and expensive, thus limiting the overall efficiency of HFSI production.

[0029] This invention provides an integrated method for effectively treating ammonium fluorosulfate byproducts to improve the overall efficiency of HFSI production. The treatment of ammonium fluorosulfate byproducts as disclosed herein can produce environmentally friendly waste products and / or commercially useful byproducts.

[0030] As disclosed herein, HFSI is produced from a solution of urea and fluorosulfonic acid. The solution of urea and fluorosulfonic acid is formed by mixing urea and fluorosulfonic acid together. The solution of urea and fluorosulfonic acid is added to a reaction medium at a reaction temperature to cause the fluorosulfonic acid and urea to react to produce a crude product containing HFSI and ammonium fluorosulfate, as shown in Formula 1. The generated carbon dioxide gas can be vented or captured for other uses. The reaction medium may contain fluorosulfonic acid and may further contain HFSI.

[0031] The reaction temperature can be as low as about 80°C, about 90°C, about 100°C, about 110°C, or about 120°C, or as high as about 130°C, about 140°C, about 150°C, about 160°C, or about 170°C, or any range defined between any two of the foregoing values, such as about 80°C to about 170°C, about 90°C to about 160°C, about 100°C to about 150°C, about 110°C to about 140°C, about 120°C to about 130°C, about 130°C to about 150°C, or about 110°C to about 120°C. Preferably, the reaction temperature is about 110°C to about 140°C. More preferably, the reaction temperature is about 120°C to about 140°C. Most preferably, the reaction temperature is about 120°C to about 130°C.

[0032] The crude product is separated into intermediate products and ammonium fluorosulfate byproducts. The crude product can be separated into intermediate products and ammonium fluorosulfate by, for example, vacuum drying, evaporation, spray drying, filtration, or any combination thereof.

[0033] The intermediate product is separated into a concentrated product and an FSA recycling product. The concentrated product contains a higher concentration of HFSI than the FSA recycling product. In some embodiments, the FSA recycling product is recycled back to the reaction medium. Alternatively or otherwise, in some embodiments, the FSA recycling product may be directed to a storage tank for later use. For example, it can be separated by distillation.

[0034] Ammonium fluorosulfate byproducts mainly consist of ammonium fluorosulfate and smaller amounts of HFSI and FSA. As used herein, the term "mainly" means 50% or more by weight (wt.%) of the byproduct. Ammonium fluorosulfate byproducts are typically solids, but can also be in slurry form of ammonium fluorosulfate and residual HFSI and FSA.

[0035] The concentration of ammonium fluorosulfate in the ammonium fluorosulfate byproduct can be as low as 50 wt%, 60 wt%, 70 wt%, 80 wt%, 85 wt%, 87 wt%, 90 wt%, 92 wt%, 94 wt%, or 95 wt%, or as high as 95.5 wt%, 96 wt%, 96.5 wt%, 97 wt%, 97.5 wt%, 98 wt%, 98.5 wt%, 99 wt%, 99.5 wt%, or 99.9 wt%, or any range defined between any two of the foregoing values, such as, for example, 50 wt%. 50% to 99.9% by weight, 60% to 99.5% by weight, 70% to 99% by weight, 80% to 98.5% by weight, 85% to 98% by weight, 87% to 97.5% by weight, 90% to 97% by weight, 92% to 96.5% by weight, 94% to 96% by weight, 95% to 95.5% by weight, 50% to 95% by weight, 90% to 99.9% by weight, 95% to 99.9% by weight or 98% to 99.5% by weight.

[0036] In some implementations, the ammonium fluorosulfate byproduct stream can be treated as follows: the ammonium fluorosulfate byproduct is mixed with water, and then the ammonium fluorosulfate byproduct is reacted with water at a hydrolysis reaction temperature to hydrolyze ammonium fluorosulfate, FSA, and HFSI, thereby forming a mixture of ammonium bisulfate (NH4HSO4), an aqueous solution of hydrogen fluoride (HF), and sulfuric acid (H2SO4) according to Formulas 2-4. Formula 2 NH4SO3F+H2O → NH4HSO4+HF, Formula 3 HSO3F+H2O → H2SO4+HF, Formula 4 HN(SO2F)2+4 H2O → NH4HSO4+2 HF+H2SO4.

[0037] The hydrolysis reaction temperature can be as low as about 20°C, about 25°C, about 30°C, about 35°C, about 40°C, about 45°C, or about 50°C, or as high as about 60°C, about 70°C, about 80°C, about 90°C, about 100°C, about 150°C, or about 200°C, or any range defined between any two of the foregoing values, such as, for example, about 20°C to about 200°C, about 25°C to about 150°C, about 30°C to about 100°C, about 35°C to about 90°C, about 40°C to about 80°C, about 45°C to about 70°C, about 50°C to about 60°C, about 35°C to about 90°C, about 40°C to about 80°C, about 20°C to about 100°C, or about 60°C to about 80°C. Preferably, the reaction temperature is about 25°C to about 80°C. More preferably, the reaction temperature is about 30°C to about 70°C. Most preferably, the reaction temperature is about 40°C to about 60°C. At temperatures exceeding approximately 100°C, the hydrolysis reaction will occur in an environment with pressures above atmospheric pressure.

[0038] For example, the ammonium bisulfate mixture is separated from the HF aqueous solution by vacuum drying, evaporation, spray drying, or any combination thereof. The ammonium bisulfate mixture is then neutralized with ammonia, and the sulfuric acid is converted into additional ammonium bisulfate according to Formula 5: Formula 5 H2SO4+NH3→ NH4HSO4.

[0039] Neutralized ammonium bisulfate can be dried by, for example, vacuum drying, evaporation, spray drying, or any combination thereof. Neutralized ammonium bisulfate can be used in other reactions or may be suitable for sale and use in applications requiring, for example, a weak acid. Alternatively, according to Formula 6, ammonium bisulfate can react with additional ammonia to produce ammonium sulfate: Formula 6 NH4HSO4+NH3→ (NH4)2SO4.

[0040] For example, ammonium sulfate can be dried by vacuum drying, evaporation, spray drying, or any combination thereof. The resulting solid ammonium sulfate may be suitable for sale and use as fertilizer.

[0041] Water in an aqueous HF solution can be separated to produce a concentrated aqueous HF solution. The water can be separated by distillation, pressure swing distillation, and / or diffusion dialysis, as is known in the art. The concentrated aqueous HF solution can be stored as it is a valuable feedstock in many industrial processes. The removed water is preferably recycled to a step involving the hydrolysis of ammonium fluorosulfate byproducts. Alternatively, or otherwise, the water can be treated as wastewater.

[0042] In some embodiments, the concentrated HF aqueous solution may be concentrated to form anhydrous hydrogen fluoride. The term "anhydrous hydrogen fluoride" means hydrogen fluoride that is substantially free of water. That is, the amount of any water in the anhydrous hydrogen fluoride is less than about 500 ppm, about 300 ppm, about 200 ppm, about 100 ppm, about 50 ppm, about 30 ppm, about 20 ppm, about 10 ppm, about 5 ppm, about 3 ppm, about 2 ppm, or about 1 ppm by weight, or less than any value defined between any two of the foregoing values. Preferably, the anhydrous hydrogen fluoride contains less than about 100 ppm of water by weight. More preferably, the anhydrous hydrogen fluoride contains less than about 10 ppm of water by weight. Most preferably, the anhydrous hydrogen fluoride contains less than about 1 ppm of water by weight.

[0043] In some other embodiments, the ammonium fluorosulfate byproduct stream can be treated by mixing the ammonium fluorosulfate byproduct with water and an alkali. There are no particular limitations on the alkali used. For clarity, calcium hydroxide is used in the following description, but it should be understood that embodiments may include the use of, for example, sodium hydroxide, potassium hydroxide, or ammonium hydroxide.

[0044] Ammonium fluorosulfate byproduct, water, and alkali (calcium hydroxide) react at the reaction temperature to hydrolyze and neutralize ammonium fluorosulfate, FSA, and HFSI according to formulas 2-4 and 6-9 (below) to form ammonia and a mixture containing calcium fluoride, calcium sulfate, ammonium bisulfate, and ammonium sulfate: Formula 2 NH4SO3F+H2O → NH4HSO4+HF, Formula 3 HSO3F+H2O → H2SO4+HF, Formula 4 HN(SO2F)2+4 H2O → NH4HSO4+2 HF+H2SO4, Formula 6 NH4HSO4+NH3→ (NH4)2SO4, Formula 7 2HF + Ca(OH)2 → CaF2 + 2 H2O, Formula 8 NH4HSO4+Ca(OH)2→ CaSO4+2 H2O+NH3, Formula 9 H2SO4+Ca(OH)2→ CaSO4+2 H2O.

[0045] Some ammonia released during the conversion of ammonium bisulfate to calcium sulfate (Formula 8) can lead to the conversion of some ammonium bisulfate to ammonium sulfate (Formula 6). Any unconsumed ammonia can be treated by an acid scrubber, as is known in the art.

[0046] The hydrolysis reaction temperature can be as low as about 20°C, about 25°C, about 30°C, about 35°C, about 40°C, about 45°C, or about 50°C, or as high as about 60°C, about 70°C, about 80°C, about 90°C, about 100°C, about 150°C, or about 200°C, or any range defined between any two of the foregoing values, such as, for example, about 20°C to about 200°C, about 25°C to about 150°C, about 30°C to about 100°C, about 35°C to about 90°C, about 40°C to about 80°C, about 45°C to about 70°C, about 50°C to about 60°C, about 35°C to about 90°C, about 40°C to about 80°C, about 20°C to about 100°C, or about 60°C to about 80°C. Preferably, the reaction temperature is about 25°C to about 80°C. More preferably, the reaction temperature is about 30°C to about 70°C. Most preferably, the reaction temperature is about 40°C to about 60°C. At temperatures exceeding approximately 100°C, the hydrolysis reaction will occur in an environment with pressures above atmospheric pressure.

[0047] A mixture containing calcium fluoride, calcium sulfate, and ammonium bisulfate can be safely deposited in landfills. Alternatively, the compounds can be separated for further use. For example, calcium fluoride can be used to prepare hydrogen fluoride or as an optical lens or window. For example, calcium sulfate can be used as a soil conditioner or cement additive. As previously mentioned, ammonium sulfate can be used as a fertilizer. For example, ammonium bisulfate can be used in other reactions or may be suitable for sale and use in applications requiring weak acids. Alternatively, ammonium bisulfate can be treated with ammonia, as described above with reference to Formula 6, to produce additional ammonium sulfate.

[0048] In some embodiments, the above method is a continuous process. In some other embodiments, the above method is semi-batch. Semi-batch means that although a significant portion of the process is continuous, the entire process is not continuous. For example, in some semi-batch embodiments, the crude product can be produced and stored continuously for a period of time, and then at a later time, the stored crude product can be processed by a separation step to separate the ammonium fluorosulfate byproduct from the crude product, thereby continuously producing intermediate and recycled products, wherein the intermediate and recycled products are stored for later use, and the ammonium fluorosulfate byproduct is stored for later processing according to any of the methods described above.

[0049] Figure 1 This is a process flow diagram showing an integrated method 10 for the continuous treatment of ammonium fluorosulfate byproducts formed in the production of bis(fluorosulfonyl)imide, according to some embodiments of this disclosure. Figure 1As shown, method 10 includes a reactor 12 configured to be connected to a urea inlet stream 14 and a fluorosulfonic acid inlet stream 16. The fluorosulfonic acid in the first fluorosulfonic acid inlet stream 16 is in liquid form and can be continuously pumped into the reactor 12. Alternatively, the fluorosulfonic acid in the fluorosulfonic acid inlet stream 16 can be added in batches. The urea in the urea inlet stream 14 is in solid form and can be continuously supplied to the reactor 12 via, for example, a solids conveying system (not shown). Alternatively, the urea in the inlet stream 14 can be added to the reactor 12 in batches.

[0050] Reactor 12 may include a reaction medium to which urea and fluorosulfonic acid are added. The reaction medium may contain fluorosulfonic acid. According to the reaction of Formula 1, the mixture of urea, fluorosulfonic acid, and the reaction medium within reactor 12 is heated to the reaction temperature, as described above, to produce a crude product stream 18 containing HFSI. Carbon dioxide can be discharged from reactor 12 through reactor vent 20. The discharged carbon dioxide can be released into the atmosphere or collected for subsequent use. Reactor 12 is configured to maintain the reaction temperature, for example, by a fluid flowing through a heat exchanger or jacketed reactor (not shown) or by an electrically heated coil (not shown). In this way, reactor 12 is configured to produce a crude product stream 18 containing HFSI, ammonium fluorosulfate, and fluorosulfonic acid.

[0051] The crude product stream 18 fluidly connects the reactor 12 to the first separator 22. The first separator 22 is configured to separate ammonium fluorosulfate from the crude product stream 18 to produce an intermediate product stream 24 and an ammonium fluorosulfate byproduct stream 26. For example, the first separator 22 may be an evaporator, a vacuum dryer, a spray dryer, a filter, a centrifuge, or any combination thereof.

[0052] Intermediate product stream 24 fluidly connects the first separator 22 to a second separator 28. The second separator 28 is configured to produce a concentrated product stream 30 and a recycle stream 32. For example, the second separator 28 may be a distillation column. The concentrated product stream 30 contains a higher concentration of HFSI than the recycle stream 32. The recycle stream 32 is fluidly connected to the reactor 12. Alternatively, the recycle stream 32 may be fluidly connected to a reaction medium recycle tank (not shown). The recycle stream 32 may be directed to the reactor 12 for continuous operation or to the reaction medium recycle tank for semi-batch operation at a later time.

[0053] exist Figure 1In the illustrated embodiment, the ammonium fluorosulfate byproduct stream 26 fluidly connects the first separator 22 to the hydrolysis tank 34, in which the ammonium fluorosulfate byproduct is mixed with water supplied by the water input stream 36. The mixture of ammonium fluorosulfate byproduct and water in the hydrolysis tank 34 is heated to the hydrolysis reaction temperature as described above to hydrolyze ammonium fluorosulfate, FSA, and HFSI, thereby forming an intermediate byproduct stream 38 containing an aqueous solution of ammonium bisulfate and hydrogen fluoride according to the reactions described in Formulas 2-4 above.

[0054] The hydrolysis tank 34 is configured to maintain the hydrolysis reaction temperature, for example, by a fluid flowing through a heat exchanger or jacketed reactor (not shown) or by an electrically heated coil (not shown). In this way, the hydrolysis tank 34 is configured to produce an intermediate byproduct stream 38 containing an aqueous solution of ammonium bisulfate and hydrogen fluoride.

[0055] Intermediate byproduct stream 38 fluidly connects hydrolysis tank 34 to byproduct separator 40. Byproduct separator 40 is configured to separate ammonium bisulfate from an aqueous hydrogen fluoride solution to produce ammonium bisulfate stream 42 and aqueous hydrogen fluoride stream 44. For example, byproduct separator 40 may be an evaporator, vacuum dryer, spray dryer, filter, centrifuge, or any combination thereof. Alternatively, in some embodiments, hydrolysis tank 34 and byproduct separator 40 may be combined into a single unit.

[0056] Hydrogen fluoride aqueous solution stream 44 fluidly connects byproduct separator 40 to HF concentrator 46. HF concentrator 46 is configured to separate water from the hydrogen fluoride aqueous solution to form concentrated hydrogen fluoride stream 48 and wastewater stream 50. HF concentrator 46 may be, for example, a pressure swing distillation system including a pair of distillation columns. The concentrated hydrogen fluoride from concentrated hydrogen fluoride stream 48 can be stored or supplied to another process requiring concentrated hydrogen fluoride. Wastewater stream 50 can be recycled (not shown) to hydrolysis tank 34 or directed to a wastewater treatment facility (not shown).

[0057] Ammonium bisulfate stream 42 fluidly connects byproduct separator 40 to neutralization tank 52, where ammonium bisulfate is mixed with ammonia supplied by ammonia input stream 54. According to the reaction described in Formula 5 above, ammonia reacts with ammonium bisulfate to form ammonium sulfate stream 56 containing ammonium sulfate. Ammonium sulfate is an aqueous solution of ammonium sulfate.

[0058] Ammonium sulfate stream 56 fluidly connects neutralization tank 52 to ammonium sulfate dryer / concentrator 58. Ammonium sulfate dryer / concentrator 58 separates water from the aqueous ammonium sulfate solution to produce concentrated ammonium sulfate stream 60 and wastewater stream 62. For example, ammonium sulfate dryer / concentrator 58 may be an evaporator, vacuum dryer, spray dryer, filter, centrifuge, or any combination thereof. For example, the concentrated ammonium sulfate in concentrated ammonium sulfate stream 60 may be suitable for sale and use as fertilizer. In some embodiments, the concentrated ammonium sulfate may be in solid form. Wastewater stream 62 may be recycled (not shown) to hydrolysis tank 34 or may be directed to a wastewater treatment facility (not shown).

[0059] therefore, Figure 1 The integrated method 10 shown provides an integrated approach for effectively treating ammonium fluorosulfate byproducts to improve the overall efficiency of HFSI production. For example... Figure 1 The treatment of ammonium fluorosulfate byproducts described herein provides commercially useful byproducts and / or environmentally friendly waste products.

[0060] Figure 2 This is a process flow diagram illustrating another integrated method 100 for the continuous treatment of ammonium fluorosulfate byproducts formed in the production of bis(fluorosulfonyl)imide, according to some embodiments of this disclosure. Figure 2 As shown, method 100 includes a reactor 12 configured to be connected to a urea inlet stream 14 and a fluorosulfonic acid inlet stream 16. The fluorosulfonic acid in the first fluorosulfonic acid inlet stream 16 is in liquid form and can be continuously pumped into the reactor 12. Alternatively, the fluorosulfonic acid in the fluorosulfonic acid inlet stream 16 can be added in batches. The urea in the urea inlet stream 14 is in solid form and can be continuously supplied to the reactor 12 via, for example, a solids conveying system (not shown). Alternatively, the urea in the inlet stream 14 can be added to the reactor 12 in batches.

[0061] Reactor 12 may include a reaction medium to which urea and fluorosulfonic acid are added. The reaction medium may contain fluorosulfonic acid. According to the reaction in Formula 1, the mixture of urea, fluorosulfonic acid, and the reaction medium within reactor 12 is heated to the reaction temperature, as described above, to produce a crude product stream 18 containing HFSI. Carbon dioxide can be discharged from reactor 12 through reactor vent 20. Reactor 12 is configured to maintain the reaction temperature, for example, by a fluid flowing through a heat exchanger or jacketed reactor (not shown) or by an electrically heated coil (not shown). In this way, reactor 12 is configured to produce a crude product stream 18 containing HFSI, ammonium fluorosulfate, and fluorosulfonic acid.

[0062] The crude product stream 18 fluidly connects the reactor 12 to the first separator 22. The first separator 22 is configured to separate ammonium fluorosulfate from the crude product stream 18 to produce an intermediate product stream 24 and an ammonium fluorosulfate byproduct stream 26. For example, the first separator 22 may be an evaporator, a vacuum dryer, a spray dryer, a filter, a centrifuge, or any combination thereof.

[0063] Intermediate product stream 24 fluidly connects the first separator 22 to a second separator 28. The second separator 28 is configured to produce a concentrated product stream 30 and a recycle stream 32. For example, the second separator 28 may be a distillation column. The concentrated product stream 30 contains a higher concentration of HFSI than the recycle stream 32. The recycle stream 32 is fluidly connected to the reactor 12. Alternatively, the recycle stream 32 may be fluidly connected to a reaction medium recycle tank (not shown). The recycle stream 32 may be directed to the reactor 12 for continuous operation or to the reaction medium recycle tank for semi-batch operation at a later time.

[0064] exist Figure 2 In the illustrated embodiment, the ammonium fluorosulfate byproduct stream 26 fluidly connects the first separator 22 to the hydrolysis / neutralization tank 102, in which the ammonium fluorosulfate byproduct is mixed with water supplied by the water input stream 104 and calcium hydroxide supplied by the calcium hydroxide input stream 106. The mixture of ammonium fluorosulfate byproduct, water, and calcium hydroxide in the hydrolysis / neutralization tank 102 is heated to the hydrolysis reaction temperature as described above to hydrolyze and neutralize ammonium fluorosulfate, FSA, and HFSI, thereby forming a waste stream 108 containing calcium fluoride, calcium sulfate, ammonium sulfate, and ammonium bisulfate, and an vent 110, according to the reactions described in formulas 2-4 and 6-9 above. Any ammonia in the vent 110 can be directed to a scrubber (not shown) for neutralization, as is known in the art.

[0065] Waste stream 108, containing only environmentally acceptable waste products, can be economically deposited in a landfill. Alternatively, waste stream 108 can be separated for further use, as described above. Therefore, Figure 2 The integrated method 100 shown provides an integrated approach for effectively treating ammonium fluorosulfate byproducts to improve the overall efficiency of HFSI production. For example... Figure 2 The treatment of ammonium fluorosulfate byproducts described herein provides commercially useful byproducts and / or environmentally friendly waste products.

[0066] Figure 1 System 10 and Figure 2 The system 100 can operate in continuous mode or semi-intermittent mode.

[0067] As used herein, the phrase “any range between any two of the preceding values” literally means any range that can be selected from any two values ​​listed before such a phrase, regardless of whether those values ​​are in the lower or higher part of the list. For example, a pair of values ​​can be selected from two lower values, two higher values, or a lower value and a higher value. As used herein, the singular forms “a,” “a,” and “the” include the plural unless the context explicitly indicates otherwise.

[0068] Regarding imprecise terminology, the terms "about" and "approximately" are used interchangeably to refer to a measurement that includes the stated measurement and any measurement reasonably close to it. A measurement reasonably close to the stated measurement deviates from the stated measurement by a considerably small amount, as understood and readily determined by one of ordinary skill in the art. Such deviations may be attributable to measurement error or to minor adjustments made to optimize performance. Where the value of such a considerably small difference would not be readily determined by one of ordinary skill in the art, the terms "about" and "approximately" may be understood to mean ±10% of the stated value.

[0069] It should be understood that the above description is merely illustrative of this disclosure. Various alternatives and modifications can be devised by those skilled in the art without departing from this disclosure. Therefore, this disclosure is intended to cover all such alternatives, modifications, and variations that fall within the scope of the appended claims.

[0070] aspect Aspect 1 is a method for treating ammonium fluorosulfate byproducts. The method includes providing an ammonium fluorosulfate byproduct comprising primarily ammonium fluorosulfate and smaller amounts of fluorosulfonic acid and bis(fluorosulfonyl)imide; mixing the ammonium fluorosulfate byproduct with water; reacting the mixture of ammonium fluorosulfate byproduct and water at a hydrolysis reaction temperature to hydrolyze the ammonium fluorosulfate, fluorosulfonic acid, and bis(fluorosulfonyl)imide to form an aqueous solution of ammonium bisulfate and hydrogen fluoride; and separating the ammonium bisulfate from the aqueous solution of hydrogen fluoride.

[0071] Aspect 2 is the method according to aspect 1, further comprising separating water from an aqueous solution of hydrogen fluoride to form concentrated hydrogen fluoride.

[0072] Aspect 3 is the method according to aspect 2, wherein separating water from an aqueous solution of hydrogen fluoride to form concentrated hydrogen fluoride includes pressure swing distillation.

[0073] Aspect 4 is the method according to aspect 2 or aspect 3, wherein the concentrated hydrogen fluoride is anhydrous hydrogen fluoride.

[0074] Aspect 5 is the method according to any one of Aspects 1-4, wherein the concentration of ammonium fluorosulfate in the ammonium fluorosulfate byproduct is from 50% by weight to 99.9% by weight of the ammonium fluorosulfate byproduct.

[0075] Aspect 6 is the method according to any one of Aspects 1-4, wherein the concentration of ammonium fluorosulfate in the ammonium fluorosulfate byproduct is from 90% by weight to 99.9% by weight of the ammonium fluorosulfate byproduct.

[0076] Aspect 7 is the method according to any one of Aspects 1-6, wherein the ammonium fluorosulfate byproduct is substantially composed of ammonium fluorosulfate, fluorosulfonic acid and bis(fluorosulfonyl)imide.

[0077] Aspect 8 is the method according to any one of aspects 1-7, wherein the hydrolysis reaction temperature is about 20°C to about 200°C.

[0078] Aspect 9 is the method according to any one of aspects 1-7, wherein the hydrolysis reaction temperature is about 40°C to about 60°C.

[0079] Aspect 10 is the method according to any one of Aspects 1-9, wherein the separation of ammonium bisulfate from an aqueous solution of hydrogen fluoride includes vacuum drying.

[0080] Aspect 11 is the method according to any one of aspects 1-10, further comprising reacting ammonium bisulfate with ammonia to form ammonium sulfate.

[0081] Aspect 12 is the method according to aspect 11, further comprising dried ammonium sulfate.

[0082] Aspect 13 is a method according to any one of aspects 1-12, wherein the method is a continuous method.

[0083] Aspect 14 is the method according to any one of aspects 1-12, wherein the method is a semi-intermittent method.

[0084] Aspect 15 is a method according to any one of Aspects 1-14, wherein the method is an integrated method further comprising the steps of: providing a solution containing fluorosulfonic acid and urea; reacting the solution containing fluorosulfonic acid and urea at a reaction temperature of about 80°C to about 170°C to produce a crude product containing bis(fluorosulfonyl)imide, fluorosulfonic acid and ammonium fluorosulfate; separating ammonium fluorosulfate from the crude product to produce an intermediate product having a higher concentration of bis(fluorosulfonyl)imide than the crude product and an ammonium fluorosulfate byproduct having a higher concentration of ammonium fluorosulfate than the crude product; and separating the intermediate product into a concentrated product and a recycled product, the concentrated product containing a higher concentration of bis(fluorosulfonyl)imide than the recycled product.

[0085] Aspect 16 is the method according to aspect 15, further comprising the step of recycling the recycled product back to reacting the solution containing fluorosulfonic acid and urea.

[0086] Aspect 17 is the method according to any one of Aspect 15 or Aspect 16, wherein separating the intermediate product into a concentrated product and a recycled product includes distilling the intermediate product.

[0087] Aspect 18 is a method for treating ammonium fluorosulfate byproducts. The method includes: providing an ammonium fluorosulfate byproduct comprising primarily ammonium fluorosulfate and smaller amounts of fluorosulfonic acid and bis(fluorosulfonyl)imide; mixing the ammonium fluorosulfate byproduct with water and an alkali; and reacting the mixture of the ammonium fluorosulfate byproduct with water and alkali at a hydrolysis reaction temperature to hydrolyze and neutralize the ammonium fluorosulfate, fluorosulfonic acid, and bis(fluorosulfonyl)imide to form a mixture comprising fluoride, sulfate, and ammonium bisulfate.

[0088] Aspect 19 is the method according to aspect 18, wherein reacting the ammonium fluorosulfate byproduct with a mixture of water and alkali further forms ammonia.

[0089] Aspect 20 is the method according to aspect 18 or aspect 19, wherein the base includes calcium hydroxide, the formed fluoride includes calcium fluoride, and the formed sulfate includes calcium sulfate.

[0090] Aspect 21 includes the method according to aspect 18 or aspect 19, wherein the base includes sodium hydroxide, the fluoride formed includes sodium fluoride, and the sulfate formed includes sodium sulfate.

[0091] Aspect 22 includes the method according to aspect 18 or aspect 19, wherein the base includes potassium hydroxide, the fluoride formed includes potassium fluoride, and the sulfate formed includes potassium sulfate.

[0092] Aspect 23 includes the method according to aspect 18 or aspect 19, wherein the base includes ammonium hydroxide, the formed fluoride includes ammonium fluoride, and the formed sulfate includes ammonium sulfate.

[0093] Aspect 24 is the method according to any one of aspects 18-23, wherein the concentration of ammonium fluorosulfate in the ammonium fluorosulfate byproduct is from 50% by weight to 99.9% by weight of the ammonium fluorosulfate byproduct.

[0094] Aspect 25 is the method according to any one of aspects 18-23, wherein the concentration of ammonium fluorosulfate in the ammonium fluorosulfate byproduct is from 90% by weight to 99.9% by weight of the ammonium fluorosulfate byproduct.

[0095] Aspect 26 is the method according to any one of aspects 18-25, wherein the ammonium fluorosulfate byproduct is substantially composed of ammonium fluorosulfate, fluorosulfonic acid and bis(fluorosulfonyl)imide.

[0096] Aspect 27 is the method according to any one of aspects 18-26, wherein the hydrolysis reaction temperature is about 20°C to about 200°C.

[0097] Aspect 28 is the method according to any one of aspects 18-26, wherein the hydrolysis reaction temperature is about 40°C to about 60°C.

[0098] Aspect 29 is a method according to any one of aspects 18-28, wherein the method is a continuous method.

[0099] Aspect 30 is the method according to any one of aspects 18-28, wherein the method is a semi-intermittent method.

[0100] Aspect 31 is a method according to any one of aspects 18-30, wherein the method is an integrated method further comprising the steps of: providing a solution containing fluorosulfonic acid and urea; reacting the solution containing fluorosulfonic acid and urea at a reaction temperature of about 80°C to about 170°C to produce a crude product containing bis(fluorosulfonyl)imide, fluorosulfonic acid and ammonium fluorosulfate; separating ammonium fluorosulfate from the crude product to produce an intermediate product having a higher concentration of bis(fluorosulfonyl)imide than the crude product and an ammonium fluorosulfate byproduct having a higher concentration of ammonium fluorosulfate than the crude product; and separating the intermediate product into a concentrated product and a recycled product, the concentrated product containing a higher concentration of bis(fluorosulfonyl)imide than the recycled product.

[0101] Aspect 32 is the method according to aspect 31, further comprising the step of recycling the recycled product back to reacting the solution containing fluorosulfonic acid and urea.

[0102] Aspect 33 is the method according to aspect 31 or aspect 32, wherein separating the intermediate product into concentrated product and recycled product includes distillation of the intermediate product.

Claims

1. A method for treating ammonium fluorosulfate byproducts, the method comprising: A composition of ammonium fluorosulfate byproducts comprising ammonium fluorosulfate, fluorosulfonic acid, and bis(fluorosulfonyl)imide is provided. The ammonium fluorosulfate byproduct composition is reacted with water to hydrolyze the ammonium fluorosulfate, the fluorosulfonic acid, and the bis(fluorosulfonyl)imide to form a product composition comprising ammonium bisulfate and an aqueous solution of hydrogen fluoride; and The ammonium bisulfate is separated from the aqueous solution of hydrogen fluoride.

2. The method according to claim 1, wherein the reaction step is carried out at a temperature of at least 35°C.

3. The method according to claim 1, wherein the reaction step is carried out at a temperature of at least 50°C.

4. The method according to claim 1, wherein the reaction step is carried out at a temperature of 50°C to 80°C.

5. The method according to any one of claims 1-4, wherein the concentration of ammonium fluorosulfate in the ammonium fluorosulfate byproduct is from 90% by weight to 99.9% by weight of the ammonium fluorosulfate byproduct.

6. The method according to any one of claims 1-4, wherein the concentration of ammonium fluorosulfate in the ammonium fluorosulfate byproduct is from 95% by weight to 99.9% by weight of the ammonium fluorosulfate byproduct.

7. The method according to any one of claims 1-6, further comprising separating water from the aqueous hydrogen fluoride solution to form concentrated hydrogen fluoride.

8. The method of claim 7, wherein the separation step comprises pressure swing distillation.

9. The method according to claim 7 or claim 8, wherein the water content of the concentrated hydrogen fluoride is less than 200 ppm.

10. The method according to claim 7 or claim 8, wherein the water content of the concentrated hydrogen fluoride is less than 100 ppm.

11. The method according to claim 7 or claim 8, wherein the water content of the concentrated hydrogen fluoride is less than 50 ppm.

12. The method according to claim 1, wherein the method is an integrated method further comprising the following steps: A solution containing fluorosulfonic acid and urea is provided; The solution containing fluorosulfonic acid and urea is reacted at a reaction temperature of about 80°C to about 170°C to produce a crude product containing bis(fluorosulfonyl)imide, fluorosulfonic acid and ammonium fluorosulfate. The crude product is separated into an intermediate product having a higher concentration of bis(fluorosulfonyl)imide than the crude product and an ammonium fluorosulfate byproduct having a higher concentration of ammonium fluorosulfate than the crude product; and The intermediate product is separated into a concentrated product and a recycled product, wherein the concentrated product contains a higher concentration of bis(fluorosulfonyl)imide than the recycled product.

13. The method of claim 12, wherein the reaction step is carried out at a reaction temperature of about 100°C to about 150°C.

14. The method of claim 12 or claim 13, further comprising recycling the recycled product to the reaction step.

15. The bis(fluorosulfonyl)imide produced by the method of claim 12.

16. The method according to any one of claims 1-14, further comprising converting ammonium bisulfate into ammonium sulfate.

17. Ammonium sulfate produced by the method of claim 16.

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