Method for recovering unreacted iodine in the trifluoroiodomethane production process

Abstract

The present invention relates to a method for recovering unreacted iodine using an unreacted iodine recovery device comprising: a gas quenching device comprising a hollow cooling body into which a reaction gas mixture containing iodine (I2) discharged from a trifluoroiodmethane (CF3I) manufacturing process by the reaction of trifluoromethane (CF3H) and iodine (I2) is supplied to one side of the upper portion, and a first injection unit into which cooling water is sprayed from the upper portion of the cooling body; and a filtration device comprising a hollow filtration body having a filter with a plurality of through holes formed in the lower portion of the gas quenching device, and a second injection unit into which cleaning water is sprayed from the upper portion. A cooling step in which a high-temperature reaction gas mixture is supplied to the above-mentioned cooling body and cooling water is sprayed from the first injection part to cool the reaction gas mixture and gaseous iodine (I2) is precipitated, and The above aqueous solution and solid iodine (I2) flow into a filtration device and undergo a filtration step in which the aqueous solution and iodine (I2) are separated by a filter, and The present invention relates to a method for recovering unreacted iodine, characterized in that the iodine (I2) filtered by the above filter is cleaned by spraying cleaning water from a second spraying unit.

Description

Technology Field

[0001] The present invention relates to a method for recovering unreacted iodine, and more specifically, to a method for recovering unreacted iodine in a process for producing trifluoroiodomethane (CF3I) by the reaction of trifluoromethane (CF3H) and iodine (I2). Background Technology

[0002] Trifluoroiodomethane (CF3I) is a substance with a Global Warming Potential (GWP) and Ozone Depletion Potential (ODP) close to zero, and it has a short atmospheric lifetime even when released into the atmosphere. Therefore, trifluoroiodomethane is expected to be used not only as a substitute gas for halon fire extinguishing agents but also as a substitute for etching gases such as CF4, C2F6, and SF6. In addition, the trifluoromethyl group (CF3 - It is a very useful compound as a fluorine-containing synthetic intermediate for surfactants, pesticides, pharmaceuticals, etc., as a raw material for introducing )

[0003] Among the methods for producing trifluoroiodomethane (CF3I), the most useful method is a method of reacting trifluoromethane with iodine in the presence of a solid catalyst in which an alkali metal or alkaline earth metal salt is supported on a support such as activated carbon or alumina, as described in detail in Japanese Patent Publication No. 10-204006.

[0004] However, no patents or literature could be found regarding a method for efficiently recovering unreacted iodine that was not synthesized from a high-temperature reaction gas mixture after the synthesis of trifluoroiodomethane (CF3I).

[0005] Furthermore, to obtain pure trifluoroiodomethane (CF3I) from the reaction gas mixture, purification using devices such as absorption or adsorption is required; however, iodine must be completely removed prior to this purification to ensure the smooth operation of the purification equipment. If unreacted iodine is not completely removed, it accumulates in the piping or equipment during the subsequent purification process after the reaction, eventually clogging the pipes or equipment over time and making further trifluoroiodomethane synthesis impossible. Therefore, a method is required to efficiently separate and recover unreacted iodine after the trifluoroiodomethane synthesis reaction. Prior art literature

[0006] Japanese Patent Publication No. JP 10-204006 The problem to be solved

[0007] The present invention is proposed to solve the problems of the conventional technology described above, and aims to provide a method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, which recovers unreacted iodine that inevitably occurs in the process of synthesizing trifluoroiodomethane (CF3I) by reacting trifluoromethane (CF3H) with iodine (I2), thereby preventing unreacted iodine from accumulating in pipes or equipment during a subsequent purification process, and reduces the cost of manufacturing trifluoroiodomethane (CF3I) by reusing the recovered iodine. means of solving the problem

[0008] For the above purpose, the present invention relates to a method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process using an unreacted iodine recovery device comprising: a gas quenching device comprising a hollow cooling body into which a reaction gas mixture containing unreacted iodine (I2) is supplied to one side of the upper portion and a first injection unit into which cooling water is sprayed from the upper portion of the cooling body; and a filtration device comprising a hollow filtration body having a filter with a plurality of through holes formed in the lower portion of the gas quenching device and a second injection unit into which cleaning water is sprayed from the upper portion;

[0009] A cooling step in which a high-temperature reaction gas mixture is supplied to the above-mentioned cooling body and cooling water is sprayed from the first injection part to cool the reaction gas mixture and gaseous iodine (I2) is precipitated, and

[0010] The above aqueous solution and solid iodine (I2) flow into a filtration device and undergo a filtration step in which the aqueous solution and iodine (I2) are separated by a filter, and

[0011] The present invention provides a method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, characterized in that the iodine (I2) filtered by the above filter is cleaned by spraying cleaning water from a second spraying unit.

[0012] In the above, the lower part of the cooling body has a shape in which the cross-sectional area becomes smaller;

[0013] The cooling water sprayed in the above cooling step and the precipitated iodine (I2) are characterized by being deposited at the bottom of the cooling body.

[0014] In the above, the gas rapid cooling device is further provided with a gas discharge pipe, which is a tubular body, on the upper side of the cooling body;

[0015] The temperature of the reaction gas mixture from which iodine (I2) has been removed in the above cooling step is in the range of 25 to 40°C, and the reaction gas mixture from which iodine (I2) has been removed is discharged through a gas discharge pipe.

[0016] In the above, the cooling water and the cleaning water are deionized water, and the temperature of the cooling water and the cleaning water is in the range of 20 to 30°C.

[0017] In the above, the unreacted iodine recovery device further includes a hollow aqueous solution reservoir connected to the lower part of the filtration device;

[0018] The mixed aqueous solution, which is a mixture of the aqueous solution that has undergone the above filtration step and the washing water that has undergone the washing step, is characterized by being contained in the above aqueous solution storage tank.

[0019] In the above, the aqueous solution reservoir is provided with a third movable pipe, which is a tubular body with one end connected to the aqueous solution reservoir and the other end connected to the first injection unit;

[0020] The mixed aqueous solution contained in the above aqueous solution storage is transferred to the first injection unit via the above third transfer pipe and circulates through the above gas quenching device, filtration device, and aqueous solution storage.

[0021] In the above, the third transfer pipe is further provided with a drain pipe that is branched and connected to a wastewater treatment facility on one side; and the mixed aqueous solution contained in the aqueous solution storage tank is discharged through the drain pipe.

[0022] In the above, the reaction gas mixture includes trifluoromethane (CF3H), trifluoroiodomethane (CF3I), iodine (I2), carbon dioxide (CO2), hydrogen fluoride (HF), hexafluoroethane (C2F6), etc.;

[0023] The cooling water stacked at the bottom of the cooling body after passing through a high-temperature reaction gas mixture in the above cooling step is characterized by containing partially dissolved hydrogen fluoride (HF) and carbon dioxide (CO2). Effects of the invention

[0024] In the trifluoroiodomethane manufacturing process according to the present invention, by removing and recovering unreacted iodine (I2) generated after the reaction in the trifluoroiodomethane (CF3I) synthesis process through the unreacted iodine recovery method, the problem of deposition in pipes or equipment during the subsequent purification process after the reaction is prevented, thereby enabling the smooth synthesis of trifluoroiodomethane (CF3I). Additionally, by reusing the recovered iodine (I2) in the trifluoroiodomethane (CF3I) synthesis process, the manufacturing cost is reduced. Brief explanation of the drawing

[0025] FIG. 1 is a flowchart illustrating the sequence of a method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process according to the present invention, and FIG. 2 is a schematic diagram illustrating an unreacted iodine recovery apparatus for recovering iodine by a method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process according to the present invention. Specific details for implementing the invention

[0026] All technical and scientific terms used in the description of the present invention, unless otherwise defined, have the meaning generally understood by those skilled in the art to which the present disclosure pertains. All terms used in the present disclosure are selected for the purpose of further clarifying the present disclosure and are not selected to limit the scope of the rights under the present disclosure.

[0027] Expressions such as "comprising," "having," "having," etc. used in the description of the present invention should be understood as open-ended terms implying the possibility of including other embodiments, unless otherwise stated in the phrase or sentence containing such expressions.

[0028] Singular expressions used in the description of the present invention may include the meaning of the plural form unless otherwise stated, and this applies likewise to singular expressions described in the claims.

[0029] Expressions such as "first," "second," etc., used in the description of the present invention are used to distinguish multiple components from one another and do not limit the order or importance of said components.

[0030] Where in the description of the present invention it is mentioned that a component is "connected" or "combined" to another component, it should be understood that the component can be directly connected or combined to the other component, or can be connected or combined through a new or different component.

[0031] The method for recovering unreacted iodine according to the present invention will be described in detail below with reference to the attached drawings.

[0032] FIG. 1 is a flowchart illustrating the sequence of a method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process according to the present invention, and FIG. 2 is a schematic diagram illustrating an unreacted iodine recovery apparatus for recovering iodine in a trifluoroiodomethane manufacturing process according to the present invention using the unreacted iodine recovery method.

[0034] In the following description, the vertical direction in Fig. 2 is explained as the up-and-down direction.

[0036] The method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process according to the present invention is a method for recovering unreacted iodine (I2) from a reaction gas mixture generated in a trifluoroiodomethane (CF3I) manufacturing process by the reaction of trifluoromethane (CF3H) and iodine (I2).

[0037] The above reaction gas mixture includes trifluoromethane (CF3H), trifluoroiodomethane (CF3I), iodine (I2), carbon dioxide (CO2), hydrogen fluoride (HF), hexafluoroethane (C2F6), etc.

[0038] The above method for recovering unreacted iodine is carried out in an unreacted iodine recovery device (100) shown in FIG. 2.

[0039] The above unreacted iodine recovery device (100) comprises a gas quenching device (110), a filtration device (120), and an aqueous solution storage tank (130).

[0040] The above gas rapid cooling device (110) comprises a cooling body (111), a first injection part (115), a gas supply pipe (113), a gas discharge pipe (117), and a first moving pipe (118).

[0041] The above cooling body (111) is provided as a hollow body. The above cooling body (111) is provided as a cylindrical hollow body. The above cooling body (111) is extended in the vertical direction, so that the vertical length is longer than the diameter.

[0042] The lower part of the cooling body (111) can be formed in various shapes, such as a cone or a hemisphere, in which the cross-sectional area decreases as it goes downward, and it is preferable that it be formed in a cone shape. By forming the lower part of the cooling body (111) in a cone shape, the iodine (I2) and cooling water accumulated at the lower part of the cooling body (111) are discharged smoothly.

[0043] The first injection unit (115) is provided on the upper part of the cooling body (111). The first injection unit (115) is provided at the upper center of the cooling body (111). The first injection unit (115) is provided as a nozzle and is connected to a first injection pipe (114), which is a tubular body.

[0044] Although FIG. 2 shows one first injection part (115), the first injection pipe (114) may be branched, and the first injection part (115) may be provided in each branched first injection pipe (114) and spaced apart from each other.

[0045] Cooling water is sprayed from the first injection unit (115). The cooling water is deionized water, and the temperature of the cooling water is in the range of 20 to 30°C.

[0046] The above gas supply pipe (113) is provided as a pipe. The above gas supply pipe (113) is provided at the top of the cooling body (111). One end of the above gas supply pipe (113) is connected to a reactor (not shown) where trifluoromethane (CF3H) and iodine (I2) react to synthesize trifluoroiodomethane (CF3I), and the other end is connected to the cooling body (111). The other end of the above gas supply pipe (113) is connected to communicate with the cooling body (111) at one side of the top of the cooling body (111).

[0047] It is preferable that the gas supply pipe (113) be positioned downwardly spaced from the upper part of the cooling body (111) and located below the first injection part (115). By positioning the gas supply pipe (113) below the first injection part (115), the cooling water sprayed from the first injection part (115) can be evenly sprayed into the reaction gas mixture flowing in through the gas supply pipe (113).

[0048] The gas discharge pipe (117) is provided as a pipe. The gas discharge pipe (117) is provided at the top of the cooling body (111). The gas discharge pipe (117) is provided at the other side of the gas supply pipe (113). One side of the gas discharge pipe (117) is connected to the top of the cooling body (111), and the other side is connected to a purification device (not shown) for purifying pure trifluoroiodomethane (CF3I). One side of the gas supply pipe (113) is connected to communicate with the cooling body (111) at the top of the cooling body (111).

[0049] It is preferable that the gas discharge pipe (117) be positioned upwardly spaced apart from the gas supply pipe (113). By positioning the gas discharge pipe (117) upwardly spaced apart from the gas supply pipe (113), the reaction gas mixture from which unreacted iodine (I2) has been removed by the cooling water can be smoothly discharged.

[0050] The first transfer pipe (118) is provided as a pipe. One end of the first transfer pipe (118) is connected to the lower end of the cooling body (111), and the other end is connected to the upper end of the filtration body (121) of the filtration device (120). The first transfer pipe (118) is provided with an opening / closing valve (119) capable of opening and closing the first transfer pipe (118) to control the flow and flow rate of the mixture of solid iodine (I2) and cooling water stacked at the bottom of the cooling body (111).

[0052] The above filtration device (120) is provided at the bottom of the gas rapid cooling device (110). The above filtration device (120) is provided as a hollow body. The first transfer pipe (118) of the gas rapid cooling device (110) is connected to the top of the above filtration device (120), so that a mixture of solid iodine (I2) and cooling water flows from the gas rapid cooling device (110) into the filtration device (120).

[0053] The above filtration device (120) comprises a filtration body (121), a filter (123), a second injection part (125), and a second moving pipe (127).

[0054] The above filter body (121) is provided as a hollow body. Inside the filter body (121), a filter (123) is provided with a plurality of through holes formed at an upward distance from the bottom portion. The diameter of the through holes formed in the filter (123) is preferably 100 to 300 mesh. An example of the above filter body (121) is a Nutsche-type filter device.

[0055] The second injection unit (125) is provided on the upper part of the filter body (121). The second injection unit (125) is provided as a nozzle and is connected to a second injection pipe (124) which is a tubular body. The second injection unit (125) is provided at the center of the upper part of the filter body (121). Although FIG. 2 shows that one second injection unit (125) is provided, the second injection pipe (124) may be branched, and the second injection unit (125) may be provided in multiple units by being provided in each branched second injection pipe (124).

[0056] Cleaning water is sprayed from the second spray unit (125). The cleaning water is deionized water, and the temperature of the cleaning water is in the range of 20 to 30°C.

[0057] The second transfer tube (127) is provided as a pipe. One end of the second transfer tube (127) is connected to the lower end of the filter body (121), and the other end is connected to the upper end of the aqueous solution storage tank (130).

[0059] The above aqueous solution storage tank (130) is provided at the bottom of the filtration device (120). The above aqueous solution storage tank (130) is provided as a hollow body. A second transfer pipe (127) of the filtration device (120) is connected to the top of the above aqueous solution storage tank (130), so that an aqueous solution from which iodine (I2) has been separated in the filtration device (120) and washing water flow into the above aqueous solution storage tank (130). The mixture of the aqueous solution from which iodine (I2) has been separated in the filtration device (120) and washing water is called a 'mixed aqueous solution'.

[0060] The above-mentioned aqueous solution storage tank (130) is provided with a third transfer pipe (131) which is a tubular body. One end of the third transfer pipe (131) is connected to the lower part of the aqueous solution storage tank (130), and the other end is connected to a first injection pipe (114) connected to a gas rapid cooling device (110).

[0061] The third transfer pipe (131) is equipped with a pump (135). By driving the pump (135), the mixed aqueous solution contained in the aqueous solution storage tank (130) flows into the first injection pipe (114) and is discharged into the first injection section (115).

[0062] The third transfer pipe (131) is further provided with a drain pipe (137) branched from the third transfer pipe (131). The third transfer pipe (131) or the drain pipe (137) may be further provided with an open / close valve (133) capable of opening and closing. The drain pipe (137) is connected to a wastewater treatment facility not illustrated.

[0063] An opening / closing valve (133) is provided on the third transfer pipe (131) or the drain pipe (137), so that the mixed aqueous solution contained in the aqueous solution storage tank (130) flows along the third transfer pipe (131) or is discharged through the drain pipe (137) and supplied to a wastewater treatment facility for treatment.

[0065] The unreacted iodine recovery method according to the present invention includes a cooling step, a filtration step, and a washing step. The recovery of unreacted iodine (I2) from the reaction gas mixture is carried out in the unreacted iodine recovery device (100) using the unreacted iodine recovery method of the present invention.

[0066] In the above cooling step, a high-temperature reaction gas mixture of 400 to 600°C is supplied into the cooling body (111) of the gas rapid cooling device (110) through the gas supply pipe (113), and cooling water is sprayed from the first injection part (115) to cool the reaction gas mixture.

[0067] The above reaction gas mixture includes trifluoromethane (CF3H), trifluoroiodomethane (CF3I), iodine (I2), carbon dioxide (CO2), hydrogen fluoride (HF), hexafluoroethane (C2F6), etc.

[0068] The cooling water sprayed from the first spray unit (115) is deionized water, and the temperature of the cooling water is in the range of 20 to 30°C.

[0069] The temperature of the reaction gas mixture is lowered by the above cooling water, and gaseous iodine (I2) is precipitated as a solid phase, and the cooling water sprayed from the first injection part (115) and the precipitated iodine (I2) are deposited at the bottom of the cooling body (111).

[0070] The cooling water stacked at the bottom of the cooling body (111) after passing through the above-mentioned high-temperature reaction gas mixture contains some hydrogen fluoride (HF) and carbon dioxide (CO2) dissolved in the reaction gas mixture. Hereinafter, the cooling water that comes into contact with the above-mentioned high-temperature reaction gas mixture and contains some hydrogen fluoride (HF) and carbon dioxide (CO2) dissolved therein is referred to as an 'aqueous solution'.

[0071] The temperature of the reaction gas mixture from which iodine (I2) has been removed during the above cooling step is in the range of 25 to 40°C, and the reaction gas mixture from which iodine (I2) has been removed is discharged through the gas discharge pipe (117) and supplied to a purification device in which trifluoroiodomethane (CF3I) purification is performed.

[0072] In the above filtration step, the solid iodine (I2) and aqueous solution stacked at the bottom of the cooling body (111) pass through the filtration device (120), and the aqueous solution and iodine (I2) are separated.

[0073] The aqueous solution and iodine (I2) supplied from the above gas quenching device (110) are separated into solid iodine (I2) by a filter (123), and the aqueous solution is discharged to an aqueous solution storage tank (130).

[0074] Before filtration, a filter cloth having a mesh of 100 to 300 can be placed on the filter (123) and then the filtration of the aqueous solution and iodine (I2) can be performed.

[0075] In the above cleaning step, the iodine (I2) filtered on the filter (123) is cleaned with cleaning water sprayed from the second spray unit (125). The above cleaning step is performed on the filter (123) with the iodine (I2) in the same state as it has passed through the above filtration step. The cleaning water is deionized water, and the temperature of the cleaning water is in the range of 20 to 30°C.

[0076] The iodine (I2) cleaned in the above cleaning step is recovered, and the cleaning water is discharged into an aqueous solution storage tank (130).

[0077] The above method for recovering unreacted iodine further includes a mixed aqueous solution circulation step.

[0078] In the above mixed aqueous solution circulation step, a mixture of the aqueous solution that has undergone the filtration step and the washing water that has undergone the washing step (hereinafter referred to as 'mixed aqueous solution') contained in the above aqueous solution storage tank (130) circulates through the unreacted iodine recovery device (100), and the above cooling step, filtration step, and washing step are performed continuously.

[0079] The mixed aqueous solution contained in the above aqueous solution storage tank (130) is discharged from the aqueous solution storage tank (130) by the operation of the pump (135), flows through the third transfer pipe (131) to the first injection pipe (114), is sprayed into the cooling body (111) through the first injection part (115), and circulates through the gas rapid cooling device (110), the filtration device (120), and the aqueous solution storage tank (130), and the above steps are performed continuously.

[0080] When the mixed aqueous solution is heavily contaminated after passing through the above gas quenching device (110) and filtration device (120), the mixed aqueous solution is discharged to a wastewater treatment facility through a drain pipe (137) provided at the bottom of the aqueous solution storage tank (130).

[0082] Hereinafter, an example of a method for recovering unreacted iodine according to the present invention will be described.

[0083] The temperature of the reaction gas mixture discharged from the reactor after the synthesis reaction of trifluoroiodomethane (CF3I) by reacting trifluoromethane (CF3H) with iodine (I2) is 550°C, the flow rate is 630 ml / min, and the composition is as shown in 'Table 1' below.

[0084] compound Composition (Volume %) Trifluoromethane (CF3H) 45.8 trifluoroiodomethane (CF3I) 14.5 Iodine (I2) 10.6 carbon dioxide (CO2) 7.1 Hydrogen fluoride (HF) 21.5 Hexafluoroethane (C2F6) 0.5 total 100

[0086] The above reaction gas mixture was supplied to the cooling body (111) of the gas quenching device (110), and at the same time, cooling water at 25°C was supplied and sprayed through the first injection part (115) at a flow rate of 480 ml / min from the top of the cooling body (111), and the above process was carried out for 4 hours (cooling stage).

[0087] The above cooling water is deionized water, and the size of the cooling body (111) is 10 cm in diameter and 30 cm in length.

[0088] In the above cooling body (111), the reaction gas mixture is lowered to 28°C by the cooling water, and the iodine (I2) gas contained in the reaction mixture gas is precipitated as solid iodine (I2) and collected at the bottom of the gas quenching device (110).

[0089] At this time, a portion of hydrogen fluoride (HF) and carbon dioxide (CO2) is dissolved in the cooling water through the reaction of the cooling water and the reaction gas mixture sprayed from the first injection unit (115), and the aqueous solution in which hydrogen fluoride (HF) and carbon dioxide (CO2) are dissolved is deposited at the bottom of the gas quenching device (110) together with solid iodine (I2).

[0090] The reaction gas mixture from which the iodine (I2), some hydrogen fluoride (HF), and carbon dioxide (CO2) have been removed is discharged through the gas discharge pipe (117).

[0091] Subsequently, the solid iodine (I2) and aqueous solution collected at the bottom of the gas quenching device (110) were supplied to a filtration device (120) and filtered using a filter (123) (filtration step). A Nutsche-type filtration device with a volume of 2L was used as the filtration device. A filter cloth with a mesh of 200 was stacked on the filter (123) and the solid iodine (I2) was separated.

[0092] Next, the iodine filtered in the above filtration device (120) was washed using 1 L of washing water, and then the solid iodine was recovered (washing step). The washing water is deionized water at 25°C.

[0093] The volume of the reaction gas mixture introduced into the above gas quenching device (110) was 151.2L, and the iodine recovered through the above process was 162.4g.

[0095] The method for recovering unreacted iodine according to the present invention is not limited to the above-described embodiments and has a diverse range of applications. Furthermore, it is understood that various modifications are possible without departing from the essence of the invention as claimed in the claims. Explanation of the symbols

[0097] 100: Unreacted iodine recovery device 110: Gas quenching device 120: Filtration device 130: Aqueous solution reservoir

Claims

Claim 1 A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process using an unreacted iodine recovery device (100), comprising: a gas rapid cooling device (110) comprising a hollow cooling body (111) into which a reaction gas mixture containing unreacted iodine (I2) is supplied to one side of the upper portion and a first injection unit (115) into which cooling water is sprayed from the upper portion of the cooling body (111); and a filtration device (120) comprising a hollow filtration body (121) having a plurality of perforations formed in the lower portion of the gas rapid cooling device (110) and a second injection unit (125) into which cleaning water is sprayed from the upper portion; wherein a high-temperature reaction gas mixture is supplied to the cooling body (111) and cooling water is sprayed from the first injection unit (115) to cool the reaction gas mixture and precipitate gaseous iodine (I2); and an aqueous solution, which is cooling water in which a portion of the reaction gas mixture is dissolved, and a solid A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, comprising: a filtration step in which iodine (I2) flows through a filtration device (120) and is separated from an aqueous solution by a filter (123); a cleaning step in which the iodine (I2) filtered by the filter (123) is cleaned by spraying cleaning water from a second spraying unit (125); the lower part of the cooling body (111) has a shape in which the cross-sectional area decreases as it goes downward; and the cooling water sprayed in the cooling step and the precipitated iodine (I2) are stacked at the lower part of the cooling body (111). Claim 2 delete Claim 3 A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, wherein, in claim 1, the gas rapid cooling device (110) is further provided with a gas discharge pipe (117) which is a tubular body on the upper side of the cooling body (111); the temperature of the reaction gas mixture from which iodine (I2) has been removed in the cooling step is in the range of 25 to 40°C, and the reaction gas mixture from which iodine (I2) has been removed is discharged through the gas discharge pipe (117). Claim 4 A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, characterized in that, in claim 1, the cooling water and the washing water are deionized water, and the temperatures of the cooling water and the washing water are in the range of 20 to 30°C. Claim 5 A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, wherein, in claim 4, the unreacted iodine recovery device (100) further comprises a hollow aqueous solution storage tank (130) connected to the lower part of the filtration device (120); and a mixed aqueous solution, which is a mixture of the aqueous solution that has undergone the filtration step and the washing water that has undergone the washing step, is contained in the aqueous solution storage tank (130). Claim 6 In claim 5, the aqueous solution storage tank (130) is provided with a third transfer pipe (131) which is a pipe body with one end connected to the aqueous solution storage tank (130) and the other end connected to the first injection unit (115); the mixed aqueous solution contained in the aqueous solution storage tank (130) is transferred to the first injection unit (115) via the third transfer pipe (131) and circulates through the gas quenching device (110), the filtration device (120), and the aqueous solution storage tank (130), characterized in that it is a method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process. Claim 7 A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, characterized in that, in claim 6, the third transfer pipe (131) is further provided with a drain pipe (137) that is branched and connected to a wastewater treatment facility on one side; and the mixed aqueous solution contained in the aqueous solution storage tank (130) is discharged through the drain pipe (137). Claim 8 A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process according to claim 1, wherein the reaction gas mixture comprises trifluoromethane (CF3H), trifluoroiodomethane (CF3I), iodine (I2), carbon dioxide (CO2), hydrogen fluoride (HF), hexafluoroethane (C2F6), etc.; and wherein the cooling water stacked at the bottom of the cooling body (111) after passing through the high-temperature reaction gas mixture in the cooling step contains partially dissolved hydrogen fluoride (HF) and carbon dioxide (CO2).

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