Method of separating hydrogen peroxide and sulfuric acid

Abstract

The present invention relates to a method of separating hydrogen peroxide and sulfuric acid, comprising: feeding an aqueous sulfuric acid solution containing hydrogen peroxide into a distillation device, and controlling the temperature at the bottom of the distillation device to be

Description

Technical Field

[0001] The present invention relates to a method for separating hydrogen peroxide and sulfuric acid, and more particularly to a method for separating sulfuric acid and hydrogen peroxide from a sulfuric acid solution containing hydrogen peroxide to form an aqueous hydrogen peroxide solution and a concentrated aqueous sulfuric acid solution, but the present invention is not limited thereto. Prior Art

[0002] In semiconductor manufacturing, high-purity chemicals are required to remove fine contaminants from the wafer surface to improve final product yield and component quality and reliability. For example, organic contaminants are typically removed from photoresist residues, but environmental sources (such as paint on walls or motor oil from pumps), plastic containers, and worker clothing are also possible sources. Specifically, peroxodic acid, formed from sulfuric acid and hydrogen peroxide, utilizes its strong oxidizing and dehydrating properties to break down carbon-hydrogen bonds in organic matter, thereby removing organic contaminants. However, sulfuric acid waste generated by peroxodic acid solutions used to clean wafers has become the largest source of process waste. Furthermore, the continuous growth of the semiconductor industry in recent years has led to a rapid increase in the amount of sulfuric acid waste generated. Consequently, the industry urgently needs technologies and methods to efficiently recover or treat this waste to address the problem of excess sulfuric acid waste.

[0003] Currently, the industry primarily uses catalytic or thermal methods to treat the aforementioned sulfuric acid wastewater. Prior art, such as Republic of China Patent Invention Publication No. 1849221, discloses a method for recovering and reusing sulfuric acid from waste sulfuric acid containing aqueous hydrogen peroxide. The method comprises the following steps: feeding sulfuric acid containing aqueous hydrogen peroxide as a raw material; adding copper oxide (CuO) as a catalyst to carry out a chemical reaction to remove the aqueous hydrogen peroxide solution; the sulfuric acid and catalyst react exothermically, and a cooling device is used to control the temperature; adding hydrogen sulfide gas to react the metals in the sulfuric acid containing metal ions generated by the chemical reaction between the sulfuric acid and the catalyst to produce metal sulfides; and filtering the reaction products to obtain the metal sulfides and high-purity dilute sulfuric acid. This method completely removes the aqueous hydrogen peroxide solution and provides high-purity dilute sulfuric acid, which can be directly used as a raw material for various chemical reactions, thereby achieving the goal of highly efficient recovery and reuse of sulfuric acid wastewater.

[0004] In addition, prior art, such as Chinese Utility Model Patent No. CN 205730408U, discloses a device for concentrating dilute sulfuric acid waste liquid containing peroxide and hydrogen peroxide aqueous solution. This device utilizes a physical process to separate the solute and solvent in the solution: an aqueous solution containing solutes such as sulfuric acid, peroxide, and hydrogen peroxide aqueous solution is heated under vacuum (95°C), causing the volatile solutes, peroxide and hydrogen peroxide, to decompose and evaporate along with water. This is then condensed through a condenser. Simultaneously, as the volume of the solution decreases, the concentration of the non-volatile solute, sulfuric acid, increases, thereby producing a finished acid of a specified concentration. Summary of the Invention

[0005] Hydrogen peroxide and sulfuric acid are both important raw materials for industrial production. In response to the growing trend of sustainable operations in international businesses, recovering hydrogen peroxide and sulfuric acid from waste sulfuric acid liquid containing hydrogen peroxide is a crucial issue. However, the inventors have discovered that conventional methods for treating waste sulfuric acid liquid containing hydrogen peroxide often destroy and remove the hydrogen peroxide, failing to recover both hydrogen peroxide and sulfuric acid. Alternatively, the recovered hydrogen peroxide contains a high concentration of sulfuric acid, requiring further processing, complicating the process and increasing costs.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for separating hydrogen peroxide and sulfuric acid, comprising: introducing an aqueous sulfuric acid solution containing hydrogen peroxide into a distillation apparatus; and controlling the temperature of the bottom of the distillation apparatus to be between 65° C. and 71° C., thereby generating a top discharge stream and a bottom discharge stream in the distillation apparatus; wherein the distillation apparatus is provided with a first packing having a length of at least 1.0 meter.

[0007] According to some embodiments of the present invention, the pressure at the top of the distillation apparatus is 5 to 10 torr.

[0008] According to some embodiments of the present invention, the temperature at the top of the distillation apparatus is 4 to 45°C.

[0009] According to some embodiments of the present invention, the specific surface area of ​​the first filler is 200 to 750 m2 / m3.

[0010] According to some embodiments of the present invention, the first filler is a metal filler, a ceramic filler, a plastic filler, a graphite filler or a combination thereof.

[0011] According to some embodiments of the present invention, the material of the first filler is silicon alloy, tantalum alloy, zirconium alloy or a combination thereof.

[0012] According to some embodiments of the present invention, the material of the first filler is polytetrafluoroethylene (PTFE), perfluoroalkoxy alkanes (PFA), fluoroplastic film (ETFE), or a combination thereof.

[0013] According to some embodiments of the present invention, the hydrogen peroxide content of the top discharge stream is 20.0 to 35.0 wt.%.

[0014] According to some embodiments of the present invention, the hydrogen peroxide content of the bottom discharge stream is less than 1.5 wt.%.

[0015] According to some embodiments of the present invention, the hydrogen peroxide content of the bottom discharge stream is less than 1.0 wt.%.

[0016] According to some embodiments of the present invention, the sulfuric acid content of the top discharge stream is less than 100 ppm.

[0017] According to some embodiments of the present invention, the sulfuric acid content of the top discharge stream is less than 10 ppm.

[0018] According to some embodiments of the present invention, the top of the distillation apparatus comprises a condensing apparatus, which is configured to control the temperature of the top discharge stream flowing through the condensing apparatus to be 1 to 5°C.

[0019] According to some embodiments of the present invention, the distillation apparatus further comprises a reflux device, which is disposed corresponding to the top of the distillation apparatus.

[0020] According to some embodiments of the present invention, the reflux ratio of the distillation apparatus is 0 to 1.0.

[0021] According to some embodiments of the present invention, the sulfuric acid content of the top discharge stream is less than 1 ppm.

[0022] The advantage of the present invention is that, by using the method of separating hydrogen peroxide and sulfuric acid of the present invention, an aqueous hydrogen peroxide solution and a concentrated aqueous sulfuric acid solution can be obtained simultaneously, thereby complying with the trend of sustainable industrial development. Simple diagram description

[0023] To make the above and other objects, features, advantages and embodiments of the present application more easily understood, the accompanying drawings are described as follows:

[0024] FIG1 is a flow chart showing the steps of a method for separating hydrogen peroxide and sulfuric acid according to one embodiment of the present invention.

[0025] FIG2 is a schematic diagram of a distillation apparatus according to an embodiment of the present invention.

[0026] FIG3 is a schematic diagram of a distillation apparatus according to an embodiment of the present invention.

[0027] The features and components in the figures are not drawn to scale; they are drawn to best illustrate the specific features and components related to the present invention. In addition, the same or similar reference numerals are used across the different figures to designate the same or similar components and parts. Implementation Method

[0028] To make the description of this application more detailed and complete, the following provides illustrative descriptions of implementations and specific embodiments of this application. However, these descriptions are not intended to be the only forms of implementing or using the specific embodiments of this application. The various embodiments disclosed below may be combined or substituted with one another where beneficial, and other embodiments may be added to one embodiment without further description or explanation. In the following description, numerous specific details are detailed to enable the reader to fully understand the following embodiments; however, the embodiments disclosed in this application may be practiced without these specific details. Furthermore, in this specification and the accompanying claims, unless the context indicates otherwise, the terms "a," "an," and "the" are intended to be plural.

[0029] Although the numerical ranges and parameters used to define the present invention are approximate, the numerical values ​​of the specific embodiments have been presented as precisely as possible. However, any numerical value inherently contains standard deviations resulting from individual testing methods.

[0030] Although the methods disclosed herein are described below using a series of operations or steps, the order in which these operations or steps are presented should not be construed as limiting the present application. For example, certain operations or steps may be performed in a different order or concurrently with other steps. Furthermore, not all operations, steps, or features must be performed to implement the present invention. Furthermore, each operation or step described herein may include multiple sub-steps or actions.

[0031] Please refer to Figures 1 and 2 . The present invention provides a method for separating hydrogen peroxide and sulfuric acid, comprising step S110: introducing an aqueous sulfuric acid solution containing hydrogen peroxide into a distillation apparatus 100; and step S120: controlling the temperature of the bottom portion 110 of the distillation apparatus 100 to be 65 to 71°C, thereby generating a top discharge stream and a bottom discharge stream in the distillation apparatus. The aqueous sulfuric acid solution containing hydrogen peroxide may be, for example, sulfuric acid waste liquid formed from a peroxodic acid solution used in semiconductor manufacturing processes, which typically contains 3.0 to 5.0 wt.% hydrogen peroxide and 60.0 to 65.0 wt.% sulfuric acid. The feed temperature of the aqueous sulfuric acid solution containing hydrogen peroxide into the distillation apparatus 100 is not limited by the present invention.

[0032] Specifically, in step S110, the aqueous sulfuric acid solution containing hydrogen peroxide may be placed in a waste liquid barrel 20. The waste liquid barrel 20 and the distillation apparatus 100 may be connected, for example, by a guide device, so that the waste sulfuric acid solution can be guided into the distillation apparatus 100. The guide device may be, for example, the pump 30 and / or pipeline shown in FIG. 2 . The type, quantity, and configuration of the pump 30 and pipeline may be adjusted according to actual needs and are not limited by the present invention.

[0033] Step S120 is the main step for separating hydrogen peroxide and sulfuric acid. Specifically, the sulfuric acid aqueous solution containing hydrogen peroxide is fed into the bottom 110 of the distillation apparatus 100. The pressure of the distillation apparatus is controlled within a specific range using a vacuum device. Then, the temperature of the bottom 110 is controlled within a specific range using a heating device. At this time, the sulfuric acid aqueous solution containing hydrogen peroxide generates a two-phase state of gas and liquid, wherein the gas contains hydrogen peroxide, sulfuric acid, and water. As the gas rises to the top 120 of the distillation apparatus 100, the sulfuric acid aqueous solution containing hydrogen peroxide is continuously fed from the top 120 into the bottom 110. The gas contacts the sulfuric acid aqueous solution containing hydrogen peroxide and generates gasification on the surface of the first filler 10. The distillation apparatus 100 is provided with a bottom outlet 110. As described above, the hydrogen peroxide is vaporized and discharged from the distillation apparatus 100 through the top outlet. Furthermore, the sulfuric acid, due to its higher boiling point, mostly remains in the liquid phase, resulting in a continuous decrease in the sulfuric acid content in the gas flowing to the top 120. As a result, the gas reaches the outlet of the top 120 to form a top outlet stream containing a higher content of hydrogen peroxide and a lower content of sulfuric acid. The outlet of the bottom 110 leads to a bottom outlet stream. As described above, since the hydrogen peroxide is vaporized and discharged from the distillation apparatus 100 through the top outlet stream, and the originally rising sulfuric acid gas continuously increases the sulfuric acid content in the liquid flowing to the bottom of the tower due to gas-liquid contact and is fed into the bottom 110, the bottom outlet stream may contain a higher content of sulfuric acid and a lower content of hydrogen peroxide.

[0034] According to some embodiments of the present invention, the temperature of the bottom portion 110 is between 65°C and 71°C, specifically, for example, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, or a range between any two of the foregoing values. Without being bound by a particular theory, the present inventors have discovered that if the temperature of the bottom portion 110 is too high, hydrogen peroxide may be easily decomposed, while if it is too low, insufficient hydrogen peroxide vaporization may occur, resulting in a high hydrogen peroxide content in the bottom discharge stream, which in turn may negatively impact the separation and recovery of hydrogen peroxide and sulfuric acid.

[0035] According to some preferred embodiments of the present invention, in order to further improve the separation efficiency of hydrogen peroxide and sulfuric acid, the pressure of the top 120 of the distillation apparatus 100 can be controlled to be 5 to 10 torr, for example: 5 torr, 6 torr, 7 torr, 8 torr, 9 torr, 10 torr, etc. torr or a range between any two of the aforementioned values; in addition or alternatively, the temperature of the top 120 of the distillation apparatus 100 can be controlled to be 4 to 45°C, for example, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C or a range between any two of the aforementioned values; in addition or alternatively, the pressure of the bottom 110 of the distillation apparatus 100 can be controlled to be 15 to 20 torr, for example, 15 torr, 16 torr, 18 torr, 20 torr, 21°C, 22°C, 23°C, 24°C, torr, 17 torr, 18 torr, 19 torr, 20 torr, or a range between any two of the aforementioned values. According to other preferred embodiments of the present invention, the pressure difference between the bottom 110 and the top 120 is at least 10 torr, specifically, for example, at least 10 torr, at least 11 torr, or at least 12 torr. When the pressure difference is controlled within the aforementioned range, good separation efficiency of hydrogen peroxide and sulfuric acid can be achieved while maintaining a moderate size of the distillation apparatus 100. If the pressure difference is too small, and the same separation efficiency is to be achieved, the size of the distillation apparatus 100 will be too large, resulting in increased costs.

[0036] According to some embodiments of the present invention, the length L of the first filler 10 is at least 1.0 meter, specifically, for example, at least 1.0 meter, at least 1.5 meters, at least 2.0 meters, at least 2.5 meters, at least 3.0 meters, at least 3.5 meters, at least 4.0 meters, at least 4.5 meters, at least 5.0 meters, at least 5.5 meters, at least 6.0 meters, at least 6.5 meters, at least 7.0 meters, at least 7.5 meters, at least 8.0 meters, at least 8.5 meters, at least 9.0 meters, at least 9.5 meters, at least 10.0 meters, or at least 10.5 meters. Without being limited by a particular theory, if the length L of the first filler is too short, the gas may easily carry a large amount of sulfuric acid to the top 120, resulting in a high sulfuric acid content in the top outlet stream, which is not conducive to the separation of hydrogen peroxide and sulfuric acid.

[0037] According to some embodiments of the present invention, the specific surface area of ​​the first filler 10 is 200 to 750 m2 / m3, for example: 200 m2 / m3, 225 m2 / m3, 250 m2 / m3, 275 m2 / m3, 300 m2 / m3, 325 m2 / m3, 350 m2 / m3, 375 m2 / m3, 400 m2 / m3, 425 m2 / m3, 450 m2 / m3, 475 m2 / m3, 500 m2 / m3, 525 m2 / m3, 550 m2 / m3, 575 m2 / m3, 600 m2 / m3, 625 m2 / m3, 650 m2 / m3, 675 m2 / m3, 700 m2 / m3, 725 m2 / m3, 750 m2 / m3 or a range between any two of the above values; when the specific surface area of ​​the first filler 10 is controlled within the above range, the separation of hydrogen peroxide and sulfuric acid can be further improved.

[0038] According to some embodiments of the present invention, the type of the first filler 10 may be, for example, bulk filler or structured filler; preferably, it is a structured filler, which is composed of fillers with different geometric shapes and corrugation angles. The geometric shape or corrugation angle can be adjusted according to actual needs. For example: in order to reduce the pressure drop, a structured filler with a corrugation angle of 30° can be used, or in order to improve the mass transfer performance, a structured filler with a corrugation angle of 45° can be used; in order to simultaneously reduce the pressure drop and improve the separation efficiency, a structured filler with a mesh-like geometry can be used.

[0039] According to some embodiments of the present invention, the first filler 10 may be, for example, a metal filler, a ceramic filler, a plastic filler, a graphite filler, or a combination thereof. More specifically, the metal filler is made of stainless steel, nickel alloys (such as Monel alloy), copper metal and its alloys, titanium metal and its alloys, silicon alloys, tantalum alloys, zirconium alloys, or a combination thereof; preferably, silicon alloys, tantalum alloys, zirconium alloys, or a combination thereof. The plastic filler may be made of, for example, polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polyvinylidene difluoride (PVDF), polytetrafluoroethylene (PTFE), perfluoroalkyl vinyl ether copolymers (PFA), fluoroplastic film (ETFE), or a combination thereof; preferably, polytetrafluoroethylene, perfluoroalkyl vinyl ether copolymers, fluoroplastic film, or a combination thereof.

[0040] According to some preferred embodiments of the present invention, the heating device used to control the temperature of the bottom portion 110 within the aforementioned specific range may be, for example, the reboiler 50 shown in FIG. 2 . Furthermore, a pump 31 may be used to circulate the aqueous sulfuric acid solution containing hydrogen peroxide through the reboiler 50 so that the solution is heated uniformly and as a whole, thereby improving the gasification efficiency.

[0041] According to some embodiments of the present invention, the distillation apparatus 100 may include a cooling device 40. When the bottom discharge stream is discharged from the distillation apparatus 100, the cooling device 40 is used to reduce the temperature of the bottom discharge stream, thereby facilitating its collection and storage in the first recovery drum 21. According to other embodiments of the present invention, the distillation apparatus 100 may include a condensing device 41. When the top discharge stream is discharged from the distillation apparatus 100, the condensing device 41 is used to condense the gas in the top discharge stream into liquid, thereby facilitating its collection and storage in the second recovery drum 22. Preferably, the temperature of the top discharge stream flowing through the condensing device 41 can be controlled to be between 1 and 5°C, for example, 1°C, 2°C, 3°C, 4°C, 5°C, or a range between any two of the aforementioned values. Furthermore, the type and number of cooling devices 40 and condensing devices 41 can be adjusted according to actual needs and are not limited by the present invention.

[0042] According to some embodiments of the present invention, the hydrogen peroxide content of the top discharge stream is calculated relative to the total weight of the top discharge stream, and is 20.0 to 35.0 wt.%, for example, 20.0 wt.%, 20.5 wt.%, 20.6 wt.%, 21.0 wt.%, 22.0 wt.%, 23.0 wt.%, 23.2 wt.%, 24.0 wt.%, 25.0 wt.%, 26.0 wt.%, 27.0 wt.%, 28.0 wt.%, 29.0 wt.%, 30.0 wt.%, 31.0 wt.%, 31.3 wt.%, 32.0 wt.%, 33.0 wt.%, 34.0 wt.%, 35.0 wt.%, or a range between any two of the foregoing values; preferably, 20.0 to 32.0 wt.%.

[0043] According to some embodiments of the present invention, the hydrogen peroxide content of the bottom discharge stream is calculated relative to the total weight of the bottom discharge stream and is less than 1.5 wt.%, specifically, less than 1.5 wt.%, less than 1.4 wt.%, less than 1.3 wt.%, less than 1.2 wt.%, less than 1.1 wt.%, less than 1.0 wt.%, less than 0.9 wt.%, less than 0.8 wt.%, less than 0.7 wt.%, less than 0.6 wt.%, less than 0.5 wt.%, less than 0.4 wt.%, less than 0.3 wt.%, less than 0.2 wt.%, or less than 0.1 wt.%, preferably less than 1.0 wt.%. In addition, the hydrogen peroxide content of the bottom discharge stream can be further reduced to 800 wt.% by a method. The hydrogen peroxide content in the bottom discharge stream is reduced to below 50 ppm, specifically below 800 ppm, below 600 ppm, below 400 ppm, below 200 ppm, below 150 ppm, below 100 ppm, and below 50 ppm; preferably, it is reduced to below 50 ppm. The method may, for example, include: reacting hydrogen chloride with hydrogen peroxide in the bottom discharge stream to produce chlorine and water; or using a metal oxide catalyst to decompose the hydrogen peroxide in the bottom discharge stream into oxygen and water at a specific temperature; or heating the bottom discharge stream at high temperature and irradiating the bottom discharge stream with ultraviolet light to decompose the hydrogen peroxide contained therein into oxygen and water, thereby reducing the hydrogen peroxide content in the bottom discharge stream.

[0044] According to some embodiments of the present invention, the sulfuric acid content of the top effluent stream is calculated relative to the total weight of the top effluent stream, and is less than 100 ppm, for example, less than 100 ppm, less than 90 ppm, less than 80 ppm, less than 70 ppm, less than 60 ppm, less than 50 ppm, less than 40 ppm, less than 30 ppm, less than 20 ppm or less than 10 ppm; preferably, less than 10 ppm.

[0045] Please refer to Figures 1 and 3 . The top of the distillation apparatus 200 may further include a reflux device 60, which is disposed corresponding to the top 220 of the distillation apparatus 200. Specifically, in step S120, the reflux device 60 is used to reflux a portion of the aforementioned overhead discharge stream back into the distillation apparatus 200. A portion of the sulfuric acid liquid in the overhead discharge stream contacts the rising sulfuric acid gas, forming a gas-liquid contact on the surface of the first filler 10. The sulfuric acid component in the gas is further absorbed into the liquid and fed to the bottom 210. This results in a lower sulfuric acid content in the refluxed overhead discharge stream, thereby improving the separation efficiency of hydrogen peroxide and sulfuric acid. According to other embodiments of the present invention, the distillation apparatus 200 may further include a second filler disposed above the first filler 10 to further enhance mass transfer performance. The type, length, and specific surface area of ​​the second filler can be adjusted according to actual needs and are not limited by the present invention. According to some preferred embodiments of the present invention, the reflux ratio of the reflux device 60 is between 0 and 1.0, specifically, for example, 0, 0.2, 0.4, 0.6, 0.8, 1.0, or a range between any two of the foregoing values. If the reflux ratio is too high, a large amount of hydrogen peroxide may be carried to the bottom of the distillation device 200, negatively impacting the separation of hydrogen peroxide and sulfuric acid. According to other preferred embodiments of the present invention, the sulfuric acid content of the refluxed overhead discharge stream is less than 1 ppm. [Example]

[0046] Hereinafter, the present invention will be further described with detailed description and specific examples. However, it should be understood that these specific examples are only used to help make the present invention easier to understand and are not used to limit the scope of the present invention.

[0047] The following describes the method for separating hydrogen peroxide and sulfuric acid used in the Examples and Comparative Examples:

[0048] Example 1: An aqueous sulfuric acid solution containing hydrogen peroxide was introduced into a distillation apparatus at a temperature (feed temperature) of 30° C. The composition of the aqueous sulfuric acid solution containing hydrogen peroxide was 60 wt.% sulfuric acid, 3 wt.% hydrogen peroxide, and 37 wt.% water. The distillation apparatus is shown in FIG2 . The bottom temperature of the distillation apparatus was 70° C., the bottom pressure was 20 torr, and the top temperature was 43° C., and the top pressure was 10 torr, thereby generating a top discharge stream and a bottom discharge stream in the distillation apparatus. The distillation apparatus was provided with a first packing material, which was a structured packing material. The first packing material had a length of 10.0 meters and a specific surface area of ​​225 m2 / m3.

[0049] Example 2: An aqueous sulfuric acid solution containing hydrogen peroxide was introduced into a distillation apparatus at a temperature (feed temperature) controlled at 30°C. The composition of the aqueous sulfuric acid solution containing hydrogen peroxide was 60 wt.% sulfuric acid, 5 wt.% hydrogen peroxide, and 35 wt.% water. The distillation apparatus is shown in FIG2 . The bottom temperature of the distillation apparatus was 65°C, the bottom pressure was 15 torr, and the top temperature was 33°C, and the top pressure was 5 torr, thereby generating a top discharge stream and a bottom discharge stream in the distillation apparatus. The distillation apparatus was provided with a first packing material, which was a structured packing material. The first packing material had a length of 5.0 meters and a specific surface area of ​​225 m2 / m3.

[0050] Example 3: An aqueous sulfuric acid solution containing hydrogen peroxide was introduced into a distillation apparatus at a temperature (feed temperature) of 30° C. The composition of the aqueous sulfuric acid solution containing hydrogen peroxide was 60 wt.% sulfuric acid, 3 wt.% hydrogen peroxide, and 37 wt.% water. The distillation apparatus, as shown in FIG3 , further included a reflux device with a reflux ratio of 0.1. The bottom temperature of the distillation apparatus was 71° C., the bottom pressure was 20 torr, and the top temperature was 13° C., and the top pressure was 10 torr, thereby generating a top discharge stream and a bottom discharge stream in the distillation apparatus. The distillation apparatus was provided with a first packing material, which was a structured packing material. The first packing material had a length of 10.5 meters and a specific surface area of ​​207 m2 / m3.

[0051] Example 4: An aqueous sulfuric acid solution containing hydrogen peroxide was introduced into a distillation apparatus at a temperature (feed temperature) of 30°C. The composition of the aqueous sulfuric acid solution containing hydrogen peroxide was 60 wt.% sulfuric acid, 5 wt.% hydrogen peroxide, and 35 wt.% water. The distillation apparatus, as shown in FIG3 , further included a reflux device with a reflux ratio of 1.0. The bottom temperature of the distillation apparatus was 70°C, the bottom pressure was 15 torr, and the top temperature was 4°C, and the top pressure was 5 torr, thereby generating a top discharge stream and a bottom discharge stream in the distillation apparatus. The distillation apparatus was provided with a first packing material, which was a structured packing material. The first packing material had a length of 10.0 meters and a specific surface area of ​​225 m2 / m3.

[0052] Example 5: An aqueous sulfuric acid solution containing hydrogen peroxide was introduced into a distillation apparatus at a temperature (feed temperature) controlled at 30°C. The composition of the aqueous sulfuric acid solution containing hydrogen peroxide was 60 wt.% sulfuric acid, 4 wt.% hydrogen peroxide, and 36 wt.% water. The distillation apparatus is shown in FIG2 . The bottom temperature of the distillation apparatus was 65°C, the bottom pressure was 15 torr, and the top temperature was 39°C, and the top pressure was 5 torr, thereby generating a top discharge stream and a bottom discharge stream in the distillation apparatus. The distillation apparatus was provided with a first packing material, which was a structured packing material. The first packing material had a length of 1.0 meter and a specific surface area of ​​225 m2 / m3.

[0053] Comparative Example 1: This was carried out according to the method disclosed in prior art (CN 205730408U), except that the distillation apparatus was not equipped with packing. An aqueous sulfuric acid solution containing hydrogen peroxide was introduced into the distillation apparatus at a controlled temperature (feed temperature) of 30°C. The composition of the aqueous sulfuric acid solution containing hydrogen peroxide was 60 wt.% sulfuric acid, 5 wt.% hydrogen peroxide, and 35 wt.% water. The bottom temperature of the distillation apparatus was 95°C, the bottom pressure was 8 torr, and the top temperature was less than 45°C, and the top pressure was 8 torr. This produced an overhead discharge stream and a bottom discharge stream.

[0054] Comparative Example 2: An aqueous sulfuric acid solution containing hydrogen peroxide was introduced into a distillation apparatus at a controlled temperature (feed temperature) of 30°C. The aqueous sulfuric acid solution containing hydrogen peroxide comprised 60 wt.% sulfuric acid, 5 wt.% hydrogen peroxide, and 35 wt.% water. The distillation apparatus, as shown in FIG3 , further included a reflux device with a reflux ratio of 1.0. The bottom temperature of the distillation apparatus was 64°C, the bottom pressure was 20 torr, and the top temperature was 15°C, and the top pressure was 10 torr, thereby generating a top discharge stream and a bottom discharge stream in the distillation apparatus. The distillation apparatus was provided with a first packing material, which was a structured packing material. The first packing material had a length of 10.5 meters and a specific surface area of ​​225 m2 / m3.

[0055] Comparative Example 3: An aqueous sulfuric acid solution containing hydrogen peroxide was introduced into a distillation apparatus at a controlled temperature (feed temperature) of 30°C. The aqueous sulfuric acid solution containing hydrogen peroxide had a composition of 60 wt.% sulfuric acid, 5 wt.% hydrogen peroxide, and 35 wt.% water. The distillation apparatus, as shown in FIG3 , further included a reflux device with a reflux ratio of 2.0. The bottom temperature of the distillation apparatus was 72°C, the bottom pressure was 15 torr, and the top temperature was 10°C, and the top pressure was 5 torr, thereby generating a top discharge stream and a bottom discharge stream in the distillation apparatus. The distillation apparatus was provided with a first packing material, which was a structured packing material. The first packing material had a length of 10.5 meters and a specific surface area of ​​225 m2 / m3.

[0056] Comparative Example 4: An aqueous sulfuric acid solution containing hydrogen peroxide was introduced into a distillation apparatus at a temperature (feed temperature) of 30°C. The composition of the aqueous sulfuric acid solution containing hydrogen peroxide was 60 wt.% sulfuric acid, 5 wt.% hydrogen peroxide, and 35 wt.% water. The distillation apparatus is shown in FIG2 . The bottom temperature of the distillation apparatus was 71°C, the bottom pressure was 7 torr, and the top temperature was 32°C, and the top pressure was 5 torr, thereby generating a top discharge stream and a bottom discharge stream in the distillation apparatus. The distillation apparatus was provided with a first packing material, which was a structured packing material. The first packing material had a length of 0.5 meters and a specific surface area of ​​128 m2 / m3.

[0057] Here, the sulfuric acid content and hydrogen peroxide content of the top discharge stream and the hydrogen peroxide content and sulfuric acid content of the bottom discharge stream of Examples 1 to 5 and Comparative Examples 1 to 4 implemented according to the above method are presented in the following Table 1.

[0058] Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Sulfuric acid content of the top discharge stream (ppm) <10 <10 <1 <1 <10 Hydrogen peroxide content of the top discharge stream (wt.%) 20.5 31.3 20.6 28.0 23.2 Hydrogen peroxide content of the bottom discharge stream (wt.%) 0.6 1.2 0.4 0.8 1.2 Sulfuric acid content of the bottom discharge stream (wt.%) 68.3 68.6 68.8 70.8 68.7

[0059] (Continued Table 1) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Sulfuric acid content of top discharge stream (ppm) >500 <10 <1 >10 Hydrogen peroxide content of the top discharge stream (wt.%) 18 27.7 19.8 21.5 Hydrogen peroxide content of the bottom discharge stream (wt.%) 0.2 2.9 2.6 0.5 Sulfuric acid content of the bottom discharge stream (wt.%) 82.0 65.4 71.1 76.4 The first packing is a structured packing made of polytetrafluoroethylene (PTFE).

[0060] As shown in Table 1, in Examples 1 to 5, in which the length of the first packing material was controlled to at least 1.0 meter and the temperature of the bottom of the distillation apparatus was controlled to 65 to 71° C., it was observed that the bottom discharge stream had a high sulfuric acid content (e.g., greater than 68.0 wt.%) and an extremely low hydrogen peroxide content (e.g., less than 1.5 wt.%), and the top discharge stream had a high hydrogen peroxide content (e.g., greater than 20.0 wt.%) and an extremely low sulfuric acid content (e.g., less than 10 ppm). In other words, concentrated sulfuric acid aqueous solution and aqueous hydrogen peroxide solution were obtained simultaneously.

[0061] In contrast, Comparative Examples 1 to 4, which did not simultaneously adjust the length of the first filler or install the first filler, and control the temperature at the bottom of the distillation apparatus within the aforementioned conditions and ranges, failed to simultaneously produce high-purity aqueous sulfuric acid and aqueous hydrogen peroxide. Specifically, Comparative Example 1, which was produced according to the method disclosed in prior art (CN 205730408U), exhibited an inability to simultaneously produce high-purity aqueous sulfuric acid and aqueous hydrogen peroxide. Due to the excessively high bottom temperature of the distillation apparatus in Comparative Example 1, hydrogen peroxide decomposed easily, resulting in a low hydrogen peroxide content in the overhead discharge stream. Furthermore, the lack of the first filler allowed the rising gas to carry a significant amount of sulfuric acid to the top of the distillation apparatus, resulting in a high sulfuric acid content in the overhead discharge stream. In Comparative Example 2, due to the excessively low bottom temperature of the distillation apparatus, insufficient hydrogen peroxide vaporization occurred, resulting in a high hydrogen peroxide content in the bottom discharge stream. In Comparative Example 3, the excessively high temperature at the bottom of the distillation apparatus facilitated the decomposition of hydrogen peroxide, resulting in a low hydrogen peroxide content in the overhead stream. Furthermore, the reflux ratio exceeded the recommended range, causing a large amount of hydrogen peroxide to be carried back to the bottom of the distillation apparatus, resulting in an excessively high hydrogen peroxide content in the bottom stream. In Comparative Example 4, the short length of the first packing allowed the rising gas to easily carry a large amount of sulfuric acid to the top of the distillation apparatus, resulting in a high sulfuric acid content in the overhead stream.

[0062] In view of this, only by simultaneously controlling the length of the first filler to at least 1.0 meter and the temperature at the bottom of the distillation apparatus to 65 to 71°C can concentrated sulfuric acid aqueous solution and hydrogen peroxide aqueous solution be obtained, thereby solving the above-mentioned technical problem.

[0063] All ranges provided herein are intended to include each specific range within a given range and combinations of subranges between the given ranges. Furthermore, all ranges provided herein are inclusive of the endpoints of the ranges unless otherwise stated. Thus, a range of 1 to 5 specifically includes 1, 2, 3, 4, and 5, as well as subranges such as 2 to 5, 3 to 5, 2 to 3, 2 to 4, 1 to 4, and so on.

[0064] All publications and patent applications cited in this specification are herein incorporated by reference, and each individual publication or patent application is specifically and individually indicated as incorporated by reference for any and all purposes. In the event of any inconsistency between this document and any publication or patent application incorporated by reference, this document controls.

[0065] 10: First filler 20: Waste liquid barrel 21: First recycling bin 22: Second recycling bin 30, 31: Pump 40: Cooling device 41: Condensing device 50:Reboiler 60: Reflux device 100, 200: Distillation unit 110, 210: bottom 120, 220: Top L: Length S110, S120: Steps

Claims

1. A method for separating hydrogen peroxide and sulfuric acid, comprising: introducing an aqueous sulfuric acid solution containing hydrogen peroxide into a distillation apparatus; and controlling the temperature of the bottom of the distillation apparatus to be 65 to 71° C., thereby generating a top discharge stream and a bottom discharge stream in the distillation apparatus; wherein the distillation apparatus is provided with a first packing having a length of at least 1.0 meter.

2. The method of claim 1, wherein the pressure at the top of the distillation apparatus is 5 to 10 torr.

3. The method of claim 1, wherein the temperature at the top of the distillation apparatus is 4 to 45°C.

4. The method of claim 1, wherein the first filler has a specific surface area of ​​200 to 225 m2 / m3.

5. The method of claim 1, wherein the first filler is a metal filler, a ceramic filler, a plastic filler, a graphite filler, or a combination thereof.

6. The method of claim 5, wherein the first filler is made of a silicon alloy, a tantalum alloy, a zirconium alloy, or a combination thereof.

7. The method of claim 5, wherein the first filler is made of polytetrafluoroethylene (PTFE), perfluoroalkoxy alkanes (PFA), fluoroplastic film (ETFE), or a combination thereof.

8. The method of claim 1, wherein the hydrogen peroxide content of the top discharge stream is 20.0 to 35.0 wt.%.

9. The method of claim 1, wherein the hydrogen peroxide content of the bottom discharge stream is less than 1.5 wt.%.

10. The method of claim 9, wherein the hydrogen peroxide content of the bottom discharge stream is less than 1.0 wt.%.

11. The method of claim 1, wherein the sulfuric acid content of the top discharge stream is less than 100 ppm.

12. The method of claim 11, wherein the sulfuric acid content of the top discharge stream is less than 10 ppm.

13. The method of claim 1, wherein the top of the distillation apparatus comprises a condensing apparatus, which is configured to control the temperature of the top discharge stream flowing through the condensing apparatus to be 1 to 5°C.

14. The method according to any one of claims 1 to 13, wherein the distillation apparatus further comprises a reflux apparatus disposed corresponding to the top of the distillation apparatus.

15. The method of claim 14, wherein the reflux ratio of the distillation apparatus is 0 to 1.

0.

16. The method of claim 14, wherein the sulfuric acid content of the overhead stream is less than 1 ppm.

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