Method for recovering unreacted iodine in trifluoromethane production process

Abstract

The present invention relates to a method for recovering unreacted iodine by using an unreacted iodine recovery apparatus comprising: a gas quenching device including a hollow cooling body, to an upper side portion of which is supplied a reaction gas mixture including iodine (I2) discharged in the process of production of trifluoroiodomethane (CF3H) by a reaction of trifluoromethane (CF3H) and iodine (I2), and a first spraying unit for spraying coolant from the upper portion of the cooling body; and a filtering device including, below the gas quenching device, a hollow filtering body provided with a filter having a plurality of through-holes, and a second spraying unit for spraying cleaning water from the upper portion of the filtering device, the method comprising: a cooling step in which a high-temperature reaction gas mixture is supplied to the cooling body, cooling water is sprayed from the first spraying unit to cool the reaction gas mixture, and gaseous iodine (I2) is precipitated; a filtering step in which the aqueous solution and solid iodine (I2) flow into the filtering device to separate the aqueous solution and iodine (I2) through the filter; and a cleaning step in which the iodine (I2) filtered through the filter is cleaned by spraying the cleaning water from the second spray unit.

Description

Method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process

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

[0002] Trifluoroiodomethane (CF3I) is a substance with a global warming potential (GWP) and ozone depletion potential (ODP) close to 0, and has a short atmospheric lifespan even when released into the atmosphere. Therefore, trifluoroiodomethane is expected to be used not only as a replacement gas for halon extinguishing agents, but also as a replacement gas for etching gases such as CF4, C2F6, and SF6. In addition, trifluoromethyl group (CF3I) - ) is a very useful compound as a raw material for introducing fluorine-containing synthetic intermediates such as surfactants, pesticides, and pharmaceuticals.

[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 containing an alkali metal or alkaline earth metal salt supported on a support such as activated carbon or alumina, which is described in detail in Japanese Patent Application Laid-Open No. 10-204006.

[0004] However, no patent or literature could be found on a method for efficiently recovering unreacted iodine that has not been synthesized from a high-temperature reaction gas mixture after a trifluoroiodomethane (CF3I) synthesis reaction.

[0005] In addition, in order to obtain pure trifluoroiodomethane (CF3I) from the reaction gas mixture, it must be purified using devices such as absorption and adsorption. However, iodine must be completely removed before this purification to ensure smooth operation of the purification device. If unreacted iodine is not completely removed, it will deposit in the pipes or devices during the subsequent purification process after the reaction, and over time, it will block the pipes or devices, making further trifluoroiodomethane synthesis impossible. Therefore, a method for efficiently separating and recovering unreacted iodine after the trifluoroiodomethane synthesis reaction is required.

[0006] The present invention has been proposed to solve the problems of the above-mentioned prior art, and the purpose of the present invention is to provide a method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, which recovers unreacted iodine that is inevitably generated in a process of synthesizing trifluoroiodomethane (CF3I) by reacting trifluoromethane (CF3H) and iodine (I2), prevents unreacted iodine from being deposited in pipes or equipment in a subsequent purification process, and reduces the cost of manufacturing trifluoroiodomethane (CF3I) by reusing the recovered iodine.

[0007] For the above purpose, the present invention provides a method for recovering unreacted iodine in a trifluoroiodomethane production process using a gas quenching device including a hollow cooling body into which a reaction gas mixture containing unreacted iodine (I2) is supplied to an upper side and a first injection unit through which cooling water is sprayed from the upper side of the cooling body, and a filtering device including a hollow filtering body having a filter having a plurality of holes formed at the lower side of the gas quenching device and a second injection unit through which cleaning water is sprayed from the upper side;

[0008] A cooling step in which a high-temperature reaction gas mixture is supplied to the above cooling body and cooling water is sprayed from the first injection unit to cool the reaction gas mixture and precipitate gaseous iodine (I2);

[0009] The above aqueous solution and solid iodine (I2) flow into a filtering device, and a filtration step is performed in which the aqueous solution and iodine (I2) are separated by a filter;

[0010] A method for recovering unreacted iodine is provided in a trifluoroiodomethane manufacturing process, characterized in that the iodine (I2) filtered through the above filter includes a cleaning step in which cleaning water is sprayed from a second injection unit to clean the iodine.

[0011] In the above, the lower part of the cooling body is shaped to have a smaller cross-sectional area;

[0012] It is characterized in that the coolant and the precipitated iodine (I2) injected in the above cooling step are layered on the lower part of the cooling body.

[0013] In the above, the gas rapid cooling device further includes a gas discharge pipe as a tube on the upper side of the cooling body;

[0014] 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 characterized in that it is discharged through a gas discharge pipe.

[0015] 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.

[0016] In the above, the unreacted iodine recovery device further includes a hollow aqueous solution storage tank connected to the lower portion of the filtering device;

[0017] The mixed aqueous solution, which is a mixture of the aqueous solution that has gone through the above filtration step and the washing water that has gone through the washing step, is characterized in that it is stored in the aqueous solution storage.

[0018] In the above, the aqueous solution storage tank is provided with a third moving pipe, which is a pipe body having one end connected to the aqueous solution storage tank and the other end connected to the first injection unit;

[0019] The mixed aqueous solution contained in the above aqueous solution storage tank is transported to the first injection unit through the third transfer pipe and circulates through the gas quenching device, the filtering device, and the aqueous solution storage tank.

[0020] In the above, the third moving pipe is further provided with a drainage pipe branched off and one side of which is connected to a wastewater treatment facility; and the mixed aqueous solution stored in the aqueous solution storage tank is discharged through the drainage pipe.

[0021] In the above, the reaction gas mixture includes trifluoromethane (CF3H), trifluoroiodomethane (CF3I), iodine (I2), carbon dioxide (CO2), hydrogen fluoride (HF), hexafluoroethane (C2F6), etc.;

[0022] In the above cooling step, the cooling water layered on the lower part of the cooling body through the high-temperature reaction gas mixture contains some dissolved hydrogen fluoride (HF) and carbon dioxide (CO2).

[0023] 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, there is an effect of preventing the problem of deposition in pipes or equipment in the subsequent purification process after the reaction, thereby enabling smooth synthesis of trifluoroiodomethane (CF3I), and further, there is an effect of reducing manufacturing costs by reusing the recovered iodine (I2) in the trifluoroiodomethane (CF3I) synthesis process.

[0024] Figure 1 is a flowchart showing the sequence of a method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process according to the present invention.

[0025] FIG. 2 is a schematic drawing of an unreacted iodine recovery device for recovering iodine using a method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process according to the present invention.

[0026] All technical and scientific terms used in the description of the present invention, unless otherwise defined, have the meanings commonly understood by those of ordinary skill in the art to which this disclosure pertains. All terms used in this disclosure have been selected for the purpose of more clearly explaining this disclosure and are not intended to limit the scope of rights under this disclosure.

[0027] Expressions such as “comprising,” “having,” and the like used in the description of the present invention should be understood as open-ended terms that imply the possibility of including other embodiments, unless otherwise stated in the phrase or sentence in which the expression is included.

[0028] The singular forms used in the description of the present invention may include plural meanings unless otherwise stated, and the same applies to the singular forms set forth in the claims.

[0029] The expressions “first,” “second,” etc. used in the description of the present invention are used to distinguish between multiple components, and do not limit the order or importance of the components.

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

[0031] Hereinafter, with reference to the attached drawings, the method for recovering unreacted iodine of the present invention will be described in detail.

[0032] FIG. 1 is a flowchart illustrating the sequence of a method for recovering unreacted iodine in a trifluoroiodomethane production process according to the present invention, and FIG. 2 is a drawing schematically illustrating an unreacted iodine recovery device for recovering iodine in a method for recovering unreacted iodine in a trifluoroiodomethane production process according to the present invention.

[0033]

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

[0035]

[0036] The method for recovering unreacted iodine in the trifluoroiodomethane manufacturing process according to the present invention is a method for recovering unreacted iodine (I2) from a reaction gas mixture generated in the 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 unreacted iodine recovery method is performed in the unreacted iodine recovery device (100) illustrated in FIG. 2.

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

[0040] The above gas rapid cooling device (110) comprises a cooling body (111), a first injection unit (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) extends in the vertical direction, and is formed so that the vertical length is longer than the diameter.

[0042] The lower part of the cooling body (111) may be formed in various shapes such as a cone or a hemisphere, with the cross-sectional area decreasing as it goes downward, and among these, a cone shape is preferable. By forming the lower part of the cooling body (111) in a cone shape, iodine (I2) and cooling water stacked on the lower part of the cooling body (111) are smoothly discharged.

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

[0044] In Fig. 2, the first injection unit (115) is illustrated as one, but the first injection pipe (114) may be branched, and the first injection units (115) may be provided in multiple places in each of the branched first injection pipes (114) and spaced apart from each other.

[0045] Cooling water is injected 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 gas supply pipe (113) is provided at the upper part of the cooling body (111). One end of the gas supply pipe (113) is connected to a reactor (not shown) in which 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 gas supply pipe (113) is connected so as to be in communication with the cooling body (111) at one side of the upper part of the cooling body (111).

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

[0048] The above gas discharge pipe (117) is provided as a pipe. The gas discharge pipe (117) is provided at the upper part 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 upper part of the cooling body (111), and the other side is connected to a purification device (not shown) for purifying pure trifluoroiodomethane (CF3I). The gas supply pipe (113) is connected at one side to be in communication with the cooling body (111) at the upper part of the cooling body (111).

[0049] It is preferable that the above gas discharge pipe (117) be positioned upwardly apart from the above gas supply pipe (113). By positioning the above gas discharge pipe (117) upwardly apart from the above 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 above first moving pipe (118) is provided as a pipe. One end of the first moving 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 filtering body (121) of the filtering device (120). The first moving pipe (118) is provided with an opening / closing valve (119) that can open / close the first moving pipe (118) to control the flow and flow rate of a mixture of solid iodine (I2) and cooling water that is deposited on the lower end of the cooling body (111).

[0051]

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

[0053] The above filter device (120) comprises a filter body (121), a filter (123), a second injection unit (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 holes formed upwardly from the bottom. The diameter of the holes formed in the filter (123) is preferably 100 to 300 mesh. An example of the filter body (121) may be a Nutsche-type filter device.

[0055] The second injection unit (125) is provided at the upper portion of the filter body (121). The second injection unit (125) is provided as a nozzle and is connected to the second injection pipe (124), which is a pipe body. The second injection unit (125) is provided at the central portion of the upper portion of the filter body (121). In Fig. 2, the second injection unit (125) is illustrated as being provided in one piece, but the second injection pipe (124) may be branched, and the second injection units (125) may be provided in multiple pieces, each of which is provided in the branched second injection pipe (124).

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

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

[0058]

[0059] The above aqueous solution storage (130) is provided at the lower portion of the filtering device (120). The aqueous solution storage (130) is provided as a hollow body. The second transfer pipe (127) of the filtering device (120) is connected to the upper portion of the aqueous solution storage (130), so that the aqueous solution from which iodine (I2) is separated in the filtering device (120) and the washing water flow into the aqueous solution storage (130). The mixture of the aqueous solution from which iodine (I2) is separated in the filtering device (120) and the washing water is referred to as a 'mixed aqueous solution'.

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

[0061] The third moving 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 to the first injection pipe (114) and is discharged to the first injection unit (115).

[0062] The third transfer pipe (131) is further provided with a drain pipe (137) branching from the third transfer pipe (131). The third transfer pipe (131) or the drain pipe (137) may further be provided with an opening / closing valve (133) that can be opened / closed. The drain pipe (137) is connected to a wastewater treatment facility (not shown).

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

[0064]

[0065] The method for recovering unreacted iodine according to the present invention comprises a cooling step, a filtration step, and a washing step. The recovery of unreacted iodine (I2) from the reaction gas mixture is performed using the unreacted iodine recovery device (100) according to the method for recovering unreacted iodine according to 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 a gas supply pipe (113), and cooling water is sprayed from the first injection unit (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 injected from the first injection 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 in a solid state. The cooling water and precipitated iodine (I2) injected from the first injection unit (115) are deposited on the lower portion of the cooling body (111).

[0070] The cooling water layered on the lower part of the cooling body (111) through the above high-temperature reaction gas mixture contains dissolved hydrogen fluoride (HF) and carbon dioxide (CO2) contained in the reaction gas mixture. Hereinafter, the cooling water that comes into contact with the above high-temperature reaction gas mixture and in which some hydrogen fluoride (HF) and carbon dioxide (CO2) are dissolved is referred to as an “aqueous solution.”

[0071] The temperature of the reaction gas mixture from which iodine (I2) has been removed through 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 (117) and supplied to a purification device where trifluoroiodomethane (CF3I) purification is performed.

[0072] In the above filtration step, the solid iodine (I2) and aqueous solution layered on the lower portion 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 the aqueous solution storage (130).

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

[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 cleaning step is performed on the filter (123) while the iodine (I2) has passed through the above filtering step. The cleaning water is deionized water, and the temperature of the cleaning water is in the range of 20 to 30°C.

[0076] In the above cleaning step, the cleaned iodine (I2) is recovered, and the cleaning water is discharged to the aqueous solution storage (130).

[0077] The above unreacted iodine recovery method 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, which are stored in the aqueous solution storage (130) (hereinafter referred to as “mixed aqueous solution”), circulates through the unreacted iodine recovery device (100), and the cooling step, filtration step, and washing step are performed continuously.

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

[0080] When the mixed aqueous solution is severely contaminated after passing through the above gas quenching device (110) and filtering 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).

[0081]

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

[0083] [Example 1]

[0084] The temperature of the reaction gas mixture discharged from the reactor after the trifluoroiodomethane (CF3I) synthesis reaction by reacting trifluoromethane (CF3H) and iodine (I2) is 550℃, the flow rate is 630㎖ / min, and the composition is as shown in 'Table 1' below.

[0085] 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 at a flow rate of 480 ml / min through the first injection unit (115) from the upper part of the cooling body (111), and the above process was performed 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] The reaction gas mixture is lowered to 28°C by the cooling water within the cooling body (111), 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 rapid cooling device (110).

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

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

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

[0092] Next, the iodine filtered through the filter device (120) was washed using 1 L of washing water, and then 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 151.2 L, and the iodine recovered through the above process was 162.4 g.

[0094]

[0095] The method for recovering unreacted iodine according to the present invention is not limited to the above-described examples, and the scope of application is diverse, and various modifications can be implemented without departing from the gist of the present invention as claimed in the claims.

[0096]

[0097] 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 in the subsequent purification process after the reaction is prevented, thereby enabling smooth synthesis of trifluoroiodomethane (CF3I), and by reusing the recovered iodine (I2) in the trifluoroiodomethane (CF3I) synthesis process, the manufacturing cost is reduced.

Claims

1. A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process using a gas rapid cooling device (110) including a hollow cooling body (111) into which a reaction gas mixture containing unreacted iodine (I2) is supplied to one side of the upper portion, a first injection unit (115) through which cooling water is sprayed from the upper portion of the cooling body (111), and a filter device (120) including a hollow filter body (121) having a filter (123) having a plurality of holes formed in the lower portion of the gas rapid cooling device (110) and a second injection unit (125) through 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 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); The above aqueous solution and solid iodine (I2) flow into a filter (120) and a filtration step in which the aqueous solution and iodine (I2) are separated by a filter (123); A method for recovering unreacted iodine in a trifluoroiodomethane production process, characterized in that it includes a cleaning step in which iodine (I2) filtered through the above filter (123) is cleaned by spraying cleaning water from a second spray unit (125).

2. In the first paragraph, the lower part of the cooling body (111) has a cross-sectional area that becomes smaller as it goes downward; A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, characterized in that the cooling water and precipitated iodine (I2) injected in the above cooling step are stacked on the lower part of the cooling body (111).

3. In the first paragraph, the gas rapid cooling device (110) is further provided with a gas discharge pipe (117) which is a tube on the upper side of the cooling body (111); A method for recovering unreacted iodine in a trifluoroiodomethane production process, characterized in that 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 (117).

4. A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, characterized in that in the second paragraph, the cooling water and the washing water are deionized water, and the temperature of the cooling water and the washing water is in the range of 20 to 30°C.

5. In the fourth paragraph, the unreacted iodine recovery device (100) further includes a hollow aqueous solution storage tank (130) connected to the lower portion of the filter device (120); A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, characterized in that a mixed aqueous solution, which is a mixture of an aqueous solution that has gone through the above filtration step and a washing water that has gone through the washing step, is stored in the aqueous solution storage (130).

6. In the fifth paragraph, the aqueous solution storage (130) is provided with a third moving pipe (131) which is a pipe body having one end connected to the aqueous solution storage (130) and the other end connected to the first injection unit (115); A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, characterized in that the mixed aqueous solution contained in the aqueous solution storage (130) is transferred to the first injection unit (115) through the third transfer pipe (131) and circulated through the gas rapid cooling device (110), the filtering device (120), and the aqueous solution storage (130).

7. A method for recovering unreacted iodine in a trifluoroiodomethane production process, characterized in that in paragraph 6, the third transfer pipe (131) is further provided with a drain pipe (137) branched and one side of which is connected to a wastewater treatment facility; and the mixed aqueous solution contained in the aqueous solution storage (130) is discharged through the drain pipe (137).

8. In the second paragraph, the reaction gas mixture includes trifluoromethane (CF3H), trifluoroiodomethane (CF3I), iodine (I2), carbon dioxide (CO2), hydrogen fluoride (HF), hexafluoroethane (C2F6), etc.; A method for recovering unreacted iodine in a trifluoroiodomethane manufacturing process, characterized in that the cooling water layered on the lower part of the cooling body (111) through the high-temperature reaction gas mixture in the above cooling step contains some dissolved hydrogen fluoride (HF) and carbon dioxide (CO2).

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