EP0261662A2 - Méthode pour enlever l'iode d'un gaz - Google Patents

Méthode pour enlever l'iode d'un gaz Download PDF

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Publication number
EP0261662A2
EP0261662A2 EP87113910A EP87113910A EP0261662A2 EP 0261662 A2 EP0261662 A2 EP 0261662A2 EP 87113910 A EP87113910 A EP 87113910A EP 87113910 A EP87113910 A EP 87113910A EP 0261662 A2 EP0261662 A2 EP 0261662A2
Authority
EP
European Patent Office
Prior art keywords
iodine
silver
gas
removal
solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP87113910A
Other languages
German (de)
English (en)
Other versions
EP0261662A3 (fr
Inventor
Takaaki Tamura
Norihiko Fujita
Mikio Kumagai
Masami Sazarashi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Atomic Energy Bureau Science and Technologie Agency Government of Japan
National Institute of Advanced Industrial Science and Technology AIST
Japan Atomic Energy Agency
Original Assignee
Atomic Energy Bureau Science and Technologie Agency Government of Japan
Agency of Industrial Science and Technology
Japan Atomic Energy Research Institute
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Atomic Energy Bureau Science and Technologie Agency Government of Japan, Agency of Industrial Science and Technology, Japan Atomic Energy Research Institute filed Critical Atomic Energy Bureau Science and Technologie Agency Government of Japan
Publication of EP0261662A2 publication Critical patent/EP0261662A2/fr
Publication of EP0261662A3 publication Critical patent/EP0261662A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/02—Treating gases

Definitions

  • the present invention relates to a method for the removal of iodine and/or iodine compounds from mixture gases.
  • DOG dissolver off gases
  • a solution of 1 - 2 mol/l caustic soda is used to absorb iodine from the DOG.
  • the scrub liquor produced contains iodine compounds such as NaI, NaOI, and NaIO3.
  • NOx nitrogen oxides
  • the Mercurex process uses a nitric acid solution of mercuric nitrate (1-14 mol/l) as a scrubbing solution into which iodine compounds are absorbed and converted to HgI2 or Hg(IO3) to be thereafter removed. Due to the use of mercury in this process, careful countermeasures are required to eliminate mercury pollution. (Refer to the above literature (1), (2) and (3).)
  • the solution of mercuric nitrate loaded with iodine and mercury, and then iodine is fixed as copper iodide and the mercury is recycled for reuse.
  • the design of this process is thus complicated. (Literature: (4) Collad, G.E.R.et al.,1978, Iodine trapping and conditioning in the Mercurex system, 16th DOE Nuclear Air Cleaning Conference, p 552)
  • the Iodox process uses a highly concentrated nitric acid of 20 - 22m mol/l as a liquid absorbent to precipitate and recover iodine compounds as HI3O8.
  • the corrosion of the equipment materials of construction by the concentrated nitric acid used is a serious disadvantage of this process. (Refer to the above literature references (1), (2) and (3).)
  • AC6120 is a sorbent consisting of amorphous silicic acid base material impregnated with silver nitrate, which is capable of efficiently absorbing and removing iodine even in the presence of NOx.
  • An object of the present invention is to provide a system which does not possess the disadvantages of the wet and dry processes described above, which can be simple in structure, which does not produce extra waste other than iodine compounds, which does not require preheating of the DOG, which does not use corrosive or hazardous chemicals such as nitric acid and mercury, and which is free from the effects of NOx and water vapor present in the DOG.
  • corrosive or hazardous chemicals such as nitric acid and mercury
  • the objects of the present invention can be achieved by contacting mixture gases or vapors containing iodine and/or iodine compounds, such as methl iodide with a solution containing silver ion and by removing iodine species contained in the said gases or vapors as a sediment or precipitate of insoluble iodides.
  • the present invention makes use of wet contact between mixture gases or vapors containing iodine and/or iodine compounds with a solution containing silver ion, and belongs to the category of wet processes rather than dry process in which silver salt is impregnated into or onto solid substrates.
  • the solution containing silver ion various kinds of silver salts such as silsver nitrate, silver sulfate, and silver carbonate, can be used.
  • concentration of silver ion can range between 0.0001 and 5 mol/l, preferably between 0.001 and 1 mol/l.
  • the solutions may contain mineral acids such as nitric acid.
  • equipment for gas-liquid contact of the solution containing silver ion and a gas to be processed one can use almost any type of equipment including conventional equipment such as a bubble tower, spray tower, plate column, wetted wall column, or the like, as well as newer types of gas-liquid contact equipment.
  • Mixture gases or vapors containing iodine and/or iodine compounds to be processed by the system in accordance with the present invention may contain, for example, about 2000 ppm of nitrogen dioxide and/or 0.5% of water vapor in addition to the iodine of any concentration, and it has been established that the presence of these substances does not adversely affect the absorption efficiency of iodine species.
  • the process of the present invention therefore permits direct introduction of the gas containing iodine into the gas-liquid contact equipment without pretreatment which, as well as the simplicity of the post-processing equipment, allows extremely simplified design.
  • iodine which precipitates as insoluble iodide can readily be separated by any usual method. Only this sediment needs to be removed as radioactive waste according to the system of the present invention and the quantity of radioactive waste is therefore much less than when using conventional dry or wet methods, this being one of the important advantages of the present invention.
  • a dry air containing 200 ppm of iodine was allowed to pass at a rate of 0.5 l/min through 50 ml of a silver nitrate solution of 10 mol/l concentration at a constant temperature of 20°C.
  • the iodine concentration at the outlet changed with time as shown in FIG. 1.
  • the concentration of residual silver ion in the solution after breakthrough was 0.005 ppm or less. This means that more than 99.9977% of the silver initially present in the solution was effectively utilized.
  • Example 2 An experiment was carried our under the same experimental conditions as in Example 2 using a solution containing 4 mol/l nitric acid and 50 mmol/l silver nitrate.
  • the iodine concentration in the treated gas changed with time as shown in FIG. 3 and a comparison with the case of 50m mol/l in Experiment 2 indicates that the absorption of iodine is hardly affected by the nitric acid in the solution.
  • the present invention provides a novel method for the removal of iodine and iodine compounds from mixture gases or vapors using a solution containing silver ions, having the foregoing enumerated characteristics and advantages.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Treating Waste Gases (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
EP87113910A 1986-09-25 1987-09-23 Méthode pour enlever l'iode d'un gaz Withdrawn EP0261662A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP227048/86 1986-09-25
JP61227048A JPS6380831A (ja) 1986-09-25 1986-09-25 気体中のヨウ素除去法

Publications (2)

Publication Number Publication Date
EP0261662A2 true EP0261662A2 (fr) 1988-03-30
EP0261662A3 EP0261662A3 (fr) 1988-06-15

Family

ID=16854709

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87113910A Withdrawn EP0261662A3 (fr) 1986-09-25 1987-09-23 Méthode pour enlever l'iode d'un gaz

Country Status (2)

Country Link
EP (1) EP0261662A3 (fr)
JP (1) JPS6380831A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0361773A1 (fr) * 1988-09-26 1990-04-04 Doryokuro Kakunenryo Kaihatsu Jigyodan Procédé pour la récupération de l'iode radioactif lors du retraitement de combustibles nucléaires irradiés
WO1995028714A1 (fr) * 1994-04-19 1995-10-26 Joint Stock Company 'kkip' Procede et agents d'elimination de l'iode dans l'atmosphere
CN102371192A (zh) * 2010-08-23 2012-03-14 中国石油化工股份有限公司 脱碘剂的制备方法
CN102371147A (zh) * 2010-08-23 2012-03-14 中国石油化工股份有限公司 脱碘剂制备方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3429655A (en) * 1966-02-09 1969-02-25 Atomic Energy Commission Method and filter for removing iodine from gases
US4370306A (en) * 1979-04-03 1983-01-25 Dechema Deutsche Gesellschaft Fur Chemisches Apparatewesen E V Process for separation of traces of gaseous contaminants from waste gases by chemical absorption

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3429655A (en) * 1966-02-09 1969-02-25 Atomic Energy Commission Method and filter for removing iodine from gases
US4370306A (en) * 1979-04-03 1983-01-25 Dechema Deutsche Gesellschaft Fur Chemisches Apparatewesen E V Process for separation of traces of gaseous contaminants from waste gases by chemical absorption

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0361773A1 (fr) * 1988-09-26 1990-04-04 Doryokuro Kakunenryo Kaihatsu Jigyodan Procédé pour la récupération de l'iode radioactif lors du retraitement de combustibles nucléaires irradiés
WO1995028714A1 (fr) * 1994-04-19 1995-10-26 Joint Stock Company 'kkip' Procede et agents d'elimination de l'iode dans l'atmosphere
CN102371192A (zh) * 2010-08-23 2012-03-14 中国石油化工股份有限公司 脱碘剂的制备方法
CN102371147A (zh) * 2010-08-23 2012-03-14 中国石油化工股份有限公司 脱碘剂制备方法
CN102371192B (zh) * 2010-08-23 2013-04-03 中国石油化工股份有限公司 脱碘剂的制备方法
CN102371147B (zh) * 2010-08-23 2013-05-08 中国石油化工股份有限公司 脱碘剂制备方法

Also Published As

Publication number Publication date
JPS6348572B2 (fr) 1988-09-29
EP0261662A3 (fr) 1988-06-15
JPS6380831A (ja) 1988-04-11

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Inventor name: FUJITA, NORIHIKO

Inventor name: SAZARASHI, MASAMI