EP0135276A1 - Procédé pour enlever les métaux de transition des solutions contenant des agents complexants - Google Patents

Procédé pour enlever les métaux de transition des solutions contenant des agents complexants Download PDF

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Publication number
EP0135276A1
EP0135276A1 EP84304725A EP84304725A EP0135276A1 EP 0135276 A1 EP0135276 A1 EP 0135276A1 EP 84304725 A EP84304725 A EP 84304725A EP 84304725 A EP84304725 A EP 84304725A EP 0135276 A1 EP0135276 A1 EP 0135276A1
Authority
EP
European Patent Office
Prior art keywords
solution
edta
exchange resin
complexing agent
anion exchange
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.)
Granted
Application number
EP84304725A
Other languages
German (de)
English (en)
Other versions
EP0135276B1 (fr
Inventor
Sharon Lando Weisberg
Alexander Peter Murray
Lawrence Frederick Becker, Jr.
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.)
CBS Corp
Original Assignee
Westinghouse Electric Corp
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 Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Publication of EP0135276A1 publication Critical patent/EP0135276A1/fr
Application granted granted Critical
Publication of EP0135276B1 publication Critical patent/EP0135276B1/fr
Expired 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
    • G21F9/007—Recovery of isotopes from radioactive waste, e.g. fission products
    • 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
    • G21F9/04—Treating liquids

Definitions

  • This invention relates to a method of removing transition metals from complexing agent-containing solutions.
  • Radioactive deposits which contain radioactive elements often form in the cooling systems of nuclear reactors. In order to safely maintain and repair the cooling system, it is necessary to remove these radioactive deposits. This can be accomplished, for example, by using an oxidizing solution of alkali permanganate followed by a decontamination solution of oxalic acid, citric acid, and ethylenediamine tetraacetic acid (EDTA).
  • EDTA ethylenediamine tetraacetic acid
  • the EDTA forms a complex with the radioactive metal ions in the deposits, which solubilizes them.
  • the decontamination solution is circulated between the cooling system and a cation exchange resin which exchanges the metal ions on the resin and frees the EDTA to solubilize additional metal ions.
  • the present invention resides in a method of removing transition metals from a solution containing a complexing agent having an equilibrium constant for the ferric ion complex formation reaction of at least 10 22 , characterized by loading an anion exchange resin with said complexing agent or a salt thereof and circulating said solution through said anion exchange resin.
  • the complexing agent is ethylene diamine tetraacetic acid or an alkali metal salt thereof.
  • the process of this invention can thus be applied to any solution containing a complex of a transition metal with a complexing agent having an equilibrium constant for the ferric ion complex formation reaction of greater than 10 22 .
  • complexing agents include ethylenediaminetetraacetic acid (EDTA), trans, 1, 2 diaminocyclohexanetetraacetic acid (DCTA), and oxybis (ethylenediaminetetraacetic acid).
  • EDTA ethylenediaminetetraacetic acid
  • DCTA 1, 2 diaminocyclohexanetetraacetic acid
  • oxybis ethylenediaminetetraacetic acid
  • Common transition metals found in nuclear reactor decontamination solutions include iron, cobalt, nickel, and chromium.
  • the temperature of the solution should be at least 40°C in order to keep this complexing agent in solution and prevent it from precipitating.
  • the temperature of the solution should be below about 100°C, however, as anion exchange resins and the reagents used in the solution may decompose above that temperature.
  • the pH of the solution is not critical but it is typically from 2 to 2% for most decontamination solutions due to the acidity of reagents which are present.
  • an anion exchange resin may be loaded with EDTA.
  • Any anion exchange resin is suitable and may be used in this invention.
  • the resin should be loaded with only EDTA and not with any other additional complexing agents because as the metal EDTA complex is absorbed by the resin, another anion (i.e., nitrilo triacetic acid NTA, citric, or oxalic) would be released, diluting the concentration of EDTA in the solution.
  • complexing agents such as NTA, or organic acids, such as citric acid and oxalic acid form much weaker transition metal complexes compared to .those formed with EDTA, and metals complexed with these other agents can be removed from solution by cation exchanges. This is not the case for EDTA-metal complexes, and as a result, the metal remains in solution using conventional removal methods.
  • the anion exchange resin is most conveniently loaded with the EDTA anion by preparing a solution of the EDTA and passing the solution through the anion exchange resin. It is desirable to use a solution of an EDTA salt, preferably an alkali earth metal salt, such as sodium EDTA, to load the anion exchange resin with the EDTA anion as this releases sodium hydroxide rather than just water into the solution. Since NaOH is highly alkaline, (pH-12-14) the pH of the solution exiting the column, after an initial rise, will fall back down to the pH of the sodium EDTA (pH-4-5) as fewer hydroxide groups of the preferred strong base anion exchange resin are replaced by the EDTA anion.
  • an EDTA salt preferably an alkali earth metal salt, such as sodium EDTA
  • the resin should be considered to be fully loaded with EDTA anion. While the acid form of EDTA can be used, it is more difficult to determine when the resin has been loaded because without the presence of the sodium ion, the solution leaving the columns will be at approximately a neutral pH value (-7). Thus, the difference in pH values of the column feed (about 4.5) and the column effluent (about 7) is significantly less than when the sodium salt is used. Also, the acid form of EDTA is not very soluble in water which means that the solution must be more dilute.
  • the decontamination solution containing the metal ion-EDTA complex is circulated between the EDTA-loaded anion exchange resin and the reactor cooling system, or the portion thereof that is being decontaminated, such as the steam generator of a pressurized water reactor or a boiling water reactor.
  • the metal ion-EDTA complex is absorbed onto the EDTA anion exchange resin, fresh EDTA is released into the decontamination solution.
  • the solution is circulated until the concentration of metal ions in the solution leaving the cooling system is not substantially greater than the concentration of metal ions in the solution entering the cooling system.
  • the EDTA and any remaining ions in the solution can be removed by passing the solution through a fresh anion exchange resin or a mixed anion-cation exchange resin, which results in relatively pure water.
  • a fresh anion exchange resin or a mixed anion-cation exchange resin which results in relatively pure water.
  • a 1 inch diamter glass column 18 inches long was partially filled with 100 ml of an anion exchange resin sold by Rohm and Haas under the trade designation "IRA-400," a strong-based polystyrene resin having a particle size between 16 and 50 mesh.
  • a solution was prepared of 100 g rams/liter of the disodium salt of EDTA. The solution, which had a pH of 4.38, was fed through the top of the column at 1-3 bed volumes/hr. and the pH of the solution leaving the bottom of the column was measured. The following table gives the pH of the solution leaving the column after various bed volumes of the solution had flowed through the column.
  • Simulated spent decontamination solutions were prepared by dissolving 50, 100, and 200 ppm of iron (from magnetite, Fe 3 0 4 ) in three 0.5 weight percent solutions of a commercially available decontamination agent believed to be 30% citric acid, 30% oxalic acid, 40% EDTA, and containing an inhibitor believed to be thiourea.
  • the three solutions were mixed in beakers with the preloaded anion exchange resin prepared in Example 1 at 54°C. After 5 hours the solutions were tested and were found to contain 3, 11, and 46 ppm of iron, respectively. This established that the EDTA-loaded anion exchange resin successfully removed iron from the solutions.
  • Example 2 A 100-ml sample of the EDTA-loaded anion exchange resin prepared as in Example 1 was placed in a 1 inch glass column 18 inches long. A 0.5% solution of the commercially available decontamination agent (described in Example 2) which contained 80 ppm of iron was passed through the column at 12 bed volumes/hr. from top to bottom and the iron, oxalate, citrate, and EDTA concentrations in the solution leaving the column were measured. The following table gives their concentrations.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Treatment Of Water By Ion Exchange (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • External Artificial Organs (AREA)
EP84304725A 1983-07-14 1984-07-11 Procédé pour enlever les métaux de transition des solutions contenant des agents complexants Expired EP0135276B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US51356783A 1983-07-14 1983-07-14
US513567 1983-07-14

Publications (2)

Publication Number Publication Date
EP0135276A1 true EP0135276A1 (fr) 1985-03-27
EP0135276B1 EP0135276B1 (fr) 1989-11-08

Family

ID=24043815

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84304725A Expired EP0135276B1 (fr) 1983-07-14 1984-07-11 Procédé pour enlever les métaux de transition des solutions contenant des agents complexants

Country Status (6)

Country Link
EP (1) EP0135276B1 (fr)
JP (1) JPS6039596A (fr)
KR (1) KR910006798B1 (fr)
CA (1) CA1229780A (fr)
DE (1) DE3480446D1 (fr)
ES (1) ES8607740A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1022349A1 (fr) * 1999-01-21 2000-07-26 United States Enrichment Corporation Procédé pour éliminer des métaux d'une solution de nettoyage à l'acide citrique
RU2458418C1 (ru) * 2012-01-10 2012-08-10 Федеральное государственное унитарное предприятие "Научно-исследовательский технологический институт имени А.П. Александрова" Способ удаления переходных металлов и радионуклидов из растворов, содержащих комплексообразующий агент

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0778554B2 (ja) * 1987-05-26 1995-08-23 荏原工業洗浄株式会社 キレ−ト化合物含有放射性廃液の処理方法
KR100699257B1 (ko) 2004-08-09 2007-03-27 삼성전자주식회사 전자렌지

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2077482A (en) * 1980-06-06 1981-12-16 Us Energy Coolant system decontamination

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5840466B2 (ja) * 1979-10-26 1983-09-06 東洋醸造株式会社 アシル−ＣｏＡ・オキシダ−ゼの製造法

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2077482A (en) * 1980-06-06 1981-12-16 Us Energy Coolant system decontamination

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1022349A1 (fr) * 1999-01-21 2000-07-26 United States Enrichment Corporation Procédé pour éliminer des métaux d'une solution de nettoyage à l'acide citrique
RU2458418C1 (ru) * 2012-01-10 2012-08-10 Федеральное государственное унитарное предприятие "Научно-исследовательский технологический институт имени А.П. Александрова" Способ удаления переходных металлов и радионуклидов из растворов, содержащих комплексообразующий агент

Also Published As

Publication number Publication date
CA1229780A (fr) 1987-12-01
JPS6039596A (ja) 1985-03-01
ES534265A0 (es) 1986-06-01
KR910006798B1 (ko) 1991-09-02
KR850001623A (ko) 1985-03-30
ES8607740A1 (es) 1986-06-01
DE3480446D1 (en) 1989-12-14
EP0135276B1 (fr) 1989-11-08

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