EP0616051B1 - Cleaning process - Google Patents

Cleaning process Download PDF

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Publication number
EP0616051B1
EP0616051B1 EP94103219A EP94103219A EP0616051B1 EP 0616051 B1 EP0616051 B1 EP 0616051B1 EP 94103219 A EP94103219 A EP 94103219A EP 94103219 A EP94103219 A EP 94103219A EP 0616051 B1 EP0616051 B1 EP 0616051B1
Authority
EP
European Patent Office
Prior art keywords
salt
lead
ammonium
metallic lead
aqueous 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.)
Expired - Lifetime
Application number
EP94103219A
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German (de)
French (fr)
Other versions
EP0616051A1 (en
Inventor
Detlef Kokemüller
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.)
Siemens AG
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Siemens AG
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Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP0616051A1 publication Critical patent/EP0616051A1/en
Application granted granted Critical
Publication of EP0616051B1 publication Critical patent/EP0616051B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/14—Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/24—Cleaning or pickling metallic material with solutions or molten salts with neutral solutions
    • 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
    • G21F9/001—Decontamination of contaminated objects, apparatus, clothes, food; Preventing contamination thereof
    • G21F9/002—Decontamination of the surface of objects with chemical or electrochemical processes
    • G21F9/004—Decontamination of the surface of objects with chemical or electrochemical processes of metallic surfaces

Definitions

  • the invention relates to a method for removing metallic lead from a component, in particular from a steam generator, with the aid of a complexing agent.
  • Such a steam generator can be part of a power plant, e.g. of a nuclear power plant.
  • EP 0 198 340 B1 and EP 0 273 182 B1 describe cleaning processes which provide for the use of complexing agents.
  • the process of EP 0 198 340 B1 provides for the use of ammonia and ethylenediamine to remove copper compounds from a container, which is in particular a steam generator. An aqueous solution of ammonia and ethylenediamine is placed in the container to be cleaned. There, ammonium complexes first form and then soluble organic ethylenediamine chelate complexes of the existing copper compounds. These complexes can then be removed mechanically in a simple manner.
  • EP 0 273 182 B1 describes a method for removing iron oxide from a container.
  • a salt solution which is made up of a complexing acid, a volatile alkalizing agent and a reducing agent.
  • the salt solution has an alkaline reducing effect.
  • the use of the salt solution forms easily soluble iron complexes that can be removed mechanically in a simple manner.
  • a method is known from US 4,540,443 with which lead-containing solder metal residues can be removed from a cooling system.
  • EDTA is used for this.
  • Such a method is also known from EP 0 470 553 A1, in which, among other things, a complexing agent and also an EDTA salt are used to remove lead-containing solder metal residues.
  • the invention had for its object to provide a method for removing metallic lead from a component, with which the lead can be removed inexpensively, effectively and quickly.
  • the object is achieved according to the invention in that the metallic lead is oxidized by blowing in oxygen, air or another oxygen-containing gas, the lead compound formed by the oxidation being complexed while lead is still being oxidized, with a salt from a complexing agent complexing acid and an alkalizing agent is used in aqueous solution, and that the resulting solution is then removed.
  • the salt used as a complexing agent is particularly suitable for converting sparingly soluble lead oxide into readily soluble complexes.
  • the method according to the invention can be used in particular in the cleaning of heat exchangers or steam generators, which can be part of a nuclear power plant.
  • metallic lead contributes to corrosion.
  • the method according to the invention can also be used elsewhere for the removal of metallic lead. For example, it can be used to remove lead from earth contaminated with heavy metals.
  • ammonium-EDTA salt and / or ammonium-PDTA salt in aqueous solution can be used as complexing agents.
  • Ammonium EDTA salt is the ammonium salt of ethylenediaminetetraacetic acid (EDTA).
  • Ammonium PDTA salt is the ammonium salt of propylenediaminetetraacetic acid (PDTA).
  • the aqueous solution of ammonium EDTA salt and / or ammonium PDTA salt has, for example, a pH value between 8 and 11. Particularly good complex formation is achieved at such a pH value.
  • air is supplied continuously as an oxidizing agent and for mixing the solution.
  • an iron (III) salt is added to support the oxidation of the metallic lead.
  • an iron III salt In the presence of an iron III salt, the oxidation takes place more quickly.
  • an aqueous solution of an iron III salt of EDTA and / or PDTA is used. It has been found that these salts accelerate the oxidation process particularly well.
  • a component with the method according to the invention for example, between 4 hours and 48 hours are required.
  • the duration depends on the amount of lead to be removed.
  • the temperature during the cleaning process is, for example, between 20 ° C. and 160 ° C.
  • a temperature of 100 ° C. is particularly suitable because the boiling process promotes thorough mixing of the cleaning solution.
  • a lower temperature can be specified, as a rule external heating is dispensed with.
  • the temperature in a steam generator to be cleaned can be, for example, 50 ° C. after the system has been switched off and before cleaning begins.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • High Energy & Nuclear Physics (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Food Science & Technology (AREA)
  • Electrochemistry (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Detergent Compositions (AREA)
  • Cleaning By Liquid Or Steam (AREA)

Description

Die Erfindung betrifft ein Verfahren zum Entfernen von metallischem Blei aus einer Komponente, insbesondere aus einem Dampferzeuger, mit Hilfe eines Komplexbildners.The invention relates to a method for removing metallic lead from a component, in particular from a steam generator, with the aid of a complexing agent.

Ein solcher Dampferzeuger kann ein Bestandteil eines Kraftwerkes, z.B. eines Kernkraftwerkes sein.Such a steam generator can be part of a power plant, e.g. of a nuclear power plant.

In der EP 0 198 340 B1 und in der EP 0 273 182 B1 sind Reinigungsverfahren beschrieben, die eine Verwendung von Komplexbildnern vorsehen. Das Verfahren der EP 0 198 340 B1 sieht den Einsatz von Ammoniak und Ethylendiamin zur Entfernung von Kupferverbindungen aus einem Behälter, der insbesondere ein Dampferzeuger ist, vor. Dabei wird eine wäßrige Lösung von Ammoniak und Ethylendiamin in den zu reinigenden Behälter gegeben. Dort bilden sich zunächst Ammoniumkomplexe und dann lösliche organische Ethylendiaminchelatkomplexe der vorhandenen Kupferverbindungen. Diese Komplexe können danach in einfacher Weise mechanisch entfernt werden. In der EP 0 273 182 B1 ist ein Verfahren zum Entfernen von Eisenoxid aus einem Behälter beschrieben. Dazu wird eine Salzlösung eingesetzt, die aus einer komplexbildenden Säure, einem flüchtigen Alkalisierungsmittel und einem Reduktionsmittel hergestellt ist. Die Salzlösung wirkt alkalisch reduzierend. Durch den Einsatz der Salzlösung bilden sich leicht lösliche Eisenkomplexe, die in einfacher Weise mechanisch entfernt werden können.EP 0 198 340 B1 and EP 0 273 182 B1 describe cleaning processes which provide for the use of complexing agents. The process of EP 0 198 340 B1 provides for the use of ammonia and ethylenediamine to remove copper compounds from a container, which is in particular a steam generator. An aqueous solution of ammonia and ethylenediamine is placed in the container to be cleaned. There, ammonium complexes first form and then soluble organic ethylenediamine chelate complexes of the existing copper compounds. These complexes can then be removed mechanically in a simple manner. EP 0 273 182 B1 describes a method for removing iron oxide from a container. For this purpose, a salt solution is used, which is made up of a complexing acid, a volatile alkalizing agent and a reducing agent. The salt solution has an alkaline reducing effect. The use of the salt solution forms easily soluble iron complexes that can be removed mechanically in a simple manner.

Aus der US 4 540 443 ist ein Verfahren bekannt, mit dem bleihaltige Lötmetallrückstände aus einem Kühlsystem entfernt werden können. Dazu wird unter anderem EDTA eingesetzt.A method is known from US 4,540,443 with which lead-containing solder metal residues can be removed from a cooling system. Among other things, EDTA is used for this.

Auch aus der EP 0 470 553 Al ist ein derartiges Verfahren bekannt, bei dem unter anderem zum Entfernen von bleihaltigen Lötmetallrückständen ein Komplexbildner und auch ein EDTA-Salz verwendet werden.Such a method is also known from EP 0 470 553 A1, in which, among other things, a complexing agent and also an EDTA salt are used to remove lead-containing solder metal residues.

Aus der US 3,438,811 ist ein Verfahren zum Entfernen von Kupfer von einer Eisenoberfläche bekannt, wozu Komplexbildner verwendet werden.A process for removing copper from an iron surface is known from US Pat. No. 3,438,811, for which complexing agents are used.

Aus der US 4,443,268 ist ein Verfahren zum Entfernen von Kupfer und Kupferoxid bekannt, wobei ein EDTA-Salz eingesetzt werden kann.A method for removing copper and copper oxide is known from US 4,443,268, wherein an EDTA salt can be used.

Es ist erkannt worden, daß in verschiedenartigen Komponenten, insbesondere in Dampferzeugern, abgelagertes metallisches Blei in vergleichbar hohem Maße wie Kupferverbindungen zur Korrosion beiträgt.It has been recognized that metallic lead deposited in various components, in particular in steam generators, contributes to corrosion to a comparable extent as copper compounds.

Der Erfindung lag die Aufgabe zugrunde, ein Verfahren zum Entfernen von metallischem Blei aus einer Komponente anzugeben, mit dem das Blei kostengünstig, effektiv und schnell entfernt werden kann.The invention had for its object to provide a method for removing metallic lead from a component, with which the lead can be removed inexpensively, effectively and quickly.

Die Aufgabe wird gemäß der Erfindung dadurch gelöst, daß durch Einblasen von Sauerstoff, Luft oder einem anderen sauerstoffhaltigen Gas das metallische Blei oxidiert wird, die durch das Oxidieren entstehende Bleiverbindung, während noch Blei oxidiert wird, komplexiert wird, wobei als Komplexbildner ein Salz aus einer komplexbildenden Säure und einem Alkalisierungsmittel in wäßriger Lösung verwendet wird, und daß danach die entstandene Lösung entfernt wird.The object is achieved according to the invention in that the metallic lead is oxidized by blowing in oxygen, air or another oxygen-containing gas, the lead compound formed by the oxidation being complexed while lead is still being oxidized, with a salt from a complexing agent complexing acid and an alkalizing agent is used in aqueous solution, and that the resulting solution is then removed.

Es hat sich herausgestellt, daß das als Komplexbildner verwendete Salz für die Umwandlung von schwerlöslichem Bleioxid in leichtlösliche Komplexe besonders geeignet ist.It has been found that the salt used as a complexing agent is particularly suitable for converting sparingly soluble lead oxide into readily soluble complexes.

Das Verfahren nach der Erfindung ist insbesondere bei der Reinigung von Wärmetauschern oder Dampferzeugern, die Teil eines Kernkraftwerkes sein können, einsetzbar. Dort trägt nämlich metallisches Blei zur Korrosion bei. Das Verfahren nach der Erfindung kann aber auch an anderer Stelle zum Entfernen von metallischem Blei eingesetzt werden. Beispielsweise kann es eingesetzt werden, um Blei aus mit Schwermetallen verunreinigter Erde zu entfernen.The method according to the invention can be used in particular in the cleaning of heat exchangers or steam generators, which can be part of a nuclear power plant. There, metallic lead contributes to corrosion. However, the method according to the invention can also be used elsewhere for the removal of metallic lead. For example, it can be used to remove lead from earth contaminated with heavy metals.

Als Komplexbildner können beispielsweise Ammonium-EDTA-Salz und/oder Ammonium-PDTA-Salz in wäßriger Lösung verwendet werden. Ammonium-EDTA-Salz ist das Ammoniumsalz der Ethylendiamintetraessigsäure (EDTA). Ammonium-PDTA-Salz ist das Ammoniumsalz der Propylendiamintetraessigsäure (PDTA). Mit jedem der genannten Salze erzielt man eine besonders effektive Umwandlung von Bleiverbindungen in leichtlösliche Bleikomplexe.For example, ammonium-EDTA salt and / or ammonium-PDTA salt in aqueous solution can be used as complexing agents. Ammonium EDTA salt is the ammonium salt of ethylenediaminetetraacetic acid (EDTA). Ammonium PDTA salt is the ammonium salt of propylenediaminetetraacetic acid (PDTA). With each of the salts mentioned, a particularly effective conversion of lead compounds into easily soluble lead complexes is achieved.

Die wässrige Lösung von Ammonium-EDTA-Salz und/oder Ammonium-PDTA-Salz hat beispielsweise einen pH-Wert zwischen 8 und 11. Bei einem solchen pH-Wert wird eine besonders gute Komplexbildung erzielt.The aqueous solution of ammonium EDTA salt and / or ammonium PDTA salt has, for example, a pH value between 8 and 11. Particularly good complex formation is achieved at such a pH value.

Beispielsweise wird als Oxidationsmittel und zum Durchmischen der Lösung kontinuierlich Luft zugeführt.For example, air is supplied continuously as an oxidizing agent and for mixing the solution.

Zum Unterstützen der Oxidation des metallischen Bleis wird beispielsweise ein Eisen-III-Salz zugeführt. In Gegenwart eines Eisen-III-Salzes läuft die Oxidation beschleunigt ab.For example, an iron (III) salt is added to support the oxidation of the metallic lead. In the presence of an iron III salt, the oxidation takes place more quickly.

Beispielsweise wird eine wäßrige Lösung eines Eisen-III-Salzes der EDTA und/ oder der PDTA eingesetzt. Es hat sich herausgestellt, daß diese Salze den Oxidationsvorgang besonders gut beschleunigen.For example, an aqueous solution of an iron III salt of EDTA and / or PDTA is used. It has been found that these salts accelerate the oxidation process particularly well.

Für eine Reinigung einer Komponente mit dem Verfahren nach der Erfindung werden beispielsweise zwischen 4 Stunden und 48 Stunden benötigt. Die Dauer ist von der Menge des zu entfernenden Bleis abhängig.For cleaning a component with the method according to the invention, for example, between 4 hours and 48 hours are required. The duration depends on the amount of lead to be removed.

Die Temperatur während des Reinigungsprozeßes beträgt beispielsweise zwischen 20° C und 160° C. Besonders geeignet ist eine Temperatur von 100° C, weil der Siedevorgang eine Durchmischung der Reinigungslösung fördert. Insbesondere bei der Reinigung von Wärmetauschern oder Dampferzeugern kann jedoch eine niedrigere Temperatur vorgegeben sein, da in der Regel auf eine externe Beheizung verzichtet wird. Die Temperatur in einem zu reinigenden Dampferzeuger kann nach dem Abschalten der Anlage und vor Beginn der Reinigung z.B. 50° C betragen.The temperature during the cleaning process is, for example, between 20 ° C. and 160 ° C. A temperature of 100 ° C. is particularly suitable because the boiling process promotes thorough mixing of the cleaning solution. In particular when cleaning heat exchangers or steam generators, however, a lower temperature can be specified, as a rule external heating is dispensed with. The temperature in a steam generator to be cleaned can be, for example, 50 ° C. after the system has been switched off and before cleaning begins.

Mit dem Verfahren nach der Erfindung wird der Vorteil erzielt, daß metallisches Blei in einfacher Weise schnell und zuverlässig beseitigt werden kann.With the method according to the invention the advantage is achieved that metallic lead can be removed quickly and reliably in a simple manner.

Claims (8)

  1. Method for removing metallic lead from a component of a power station, in particular from a steam generator, with the aid of a complexing agent, characterised in that by blowing in oxygen, air or another oxygen-containing gas, the metallic lead is oxidized, the lead compound which results from the oxidation is complexed, while more lead is being oxidized, with a salt consisting of a complexing acid and an alkalizing agent in aqueous solution being used as a complexing agent, and in that after this the solution which results is removed.
  2. Method according to claim 1, characterised in that the aqueous solution has a pH value between 8 and 11.
  3. Method according to one of the claims 1 or 2, characterised in that ammonium-EDTA salt and/or ammonium-PDTA salt in aqueous solution is used as a complexing agent.
  4. Method according to one of the claims 1 to 3, characterised in that air is supplied continuously.
  5. Method according to one of the claims 1 to 4, characterised in that in order to support the oxidation of the metallic lead, an iron-III salt is added.
  6. Method according to claim 5, characterised in that in order to support the oxidation of the metallic lead, a solution of the iron-III salt is added to the EDTA and/or to the PDTA.
  7. Method according to one of the claims 1 to 6, characterised in that four hours to forty-eight hours are required.
  8. Method according to one of the claims 1 to 7, characterised in that the temperature amounts to between 20°C and 160°C.
EP94103219A 1993-03-15 1994-03-03 Cleaning process Expired - Lifetime EP0616051B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4308209A DE4308209C2 (en) 1993-03-15 1993-03-15 Process for removing metallic lead
DE4308209 1993-03-15

Publications (2)

Publication Number Publication Date
EP0616051A1 EP0616051A1 (en) 1994-09-21
EP0616051B1 true EP0616051B1 (en) 1997-05-21

Family

ID=6482853

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94103219A Expired - Lifetime EP0616051B1 (en) 1993-03-15 1994-03-03 Cleaning process

Country Status (7)

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EP (1) EP0616051B1 (en)
JP (1) JPH06322567A (en)
BR (1) BR9401146A (en)
CA (1) CA2118829A1 (en)
DE (2) DE4308209C2 (en)
ES (1) ES2102082T3 (en)
FI (1) FI941216A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB202218581D0 (en) * 2022-12-09 2023-01-25 Bluesky Environmental Engineering Ltd Compositions for the removal of deposits and methods of use

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB988129A (en) * 1962-11-01 1965-04-07 Bendix Corp Composition for removing finishing compounds from metal surfaces
FR1373143A (en) * 1963-08-10 1964-09-25 Soceti Soc Civ Ile D Etudes Te Process and product for pickling articles of ordinary steel
NL149551B (en) * 1964-08-04 1976-05-17 Dow Chemical Co METHOD FOR CLEANING AND PASSIVING IRON-CONTAINING METAL SURFACES ON WHICH METALLIC COPPER HAS BEEN DEPOSITED.
US3664870A (en) * 1969-10-29 1972-05-23 Nalco Chemical Co Removal and separation of metallic oxide scale
US4287002A (en) * 1979-04-09 1981-09-01 Atomic Energy Of Canada Ltd. Nuclear reactor decontamination
US4443268A (en) * 1981-11-12 1984-04-17 The Dow Chemical Company Process for removing copper and copper oxide encrustations from ferrous surfaces
US4578162A (en) * 1984-05-29 1986-03-25 The Dow Chemical Company Method for dissolving copper in the presence of iron
US4540443A (en) * 1984-06-15 1985-09-10 Union Carbide Corporation Cooling system cleaning composition
DE3533886A1 (en) * 1985-04-16 1987-03-26 Kraftwerk Union Ag CLEANING PROCEDURE
DE3771859D1 (en) * 1986-12-01 1991-09-05 Siemens Ag METHOD FOR CLEANING A CONTAINER.
EP0470553B1 (en) * 1990-08-06 1994-04-06 Basf Corporation Cooling system cleaning solutions
US5071582A (en) * 1990-08-06 1991-12-10 Basf Corporation Coolant system cleaning solutions having silicate or siliconate-based corrosion inhibitors
JPH04263874A (en) * 1991-02-18 1992-09-18 Jgc Corp Method for cleaning soil contaminated with heavy metal

Also Published As

Publication number Publication date
ES2102082T3 (en) 1997-07-16
JPH06322567A (en) 1994-11-22
FI941216A (en) 1994-09-16
DE4308209C2 (en) 1996-12-05
BR9401146A (en) 1994-10-25
CA2118829A1 (en) 1994-09-16
EP0616051A1 (en) 1994-09-21
DE4308209A1 (en) 1994-09-22
FI941216A0 (en) 1994-03-15
DE59402793D1 (en) 1997-06-26

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