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WO1997022975A2 - Process for using contaminated metal parts - Google Patents

Process for using contaminated metal parts Download PDF

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Publication number
WO1997022975A2
WO1997022975A2 PCT/DE1996/002309 DE9602309W WO9722975A2 WO 1997022975 A2 WO1997022975 A2 WO 1997022975A2 DE 9602309 W DE9602309 W DE 9602309W WO 9722975 A2 WO9722975 A2 WO 9722975A2
Authority
WO
WIPO (PCT)
Prior art keywords
slag
melt
metal parts
separated
liquid
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.)
Ceased
Application number
PCT/DE1996/002309
Other languages
German (de)
French (fr)
Other versions
WO1997022975A3 (en
Inventor
Ernst Haas
Nikolaus Neudert
Roland Hofmann
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
Siemens Corp
Original Assignee
Siemens AG
Siemens 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 Siemens AG, Siemens Corp filed Critical Siemens AG
Priority to AU18681/97A priority Critical patent/AU1868197A/en
Publication of WO1997022975A2 publication Critical patent/WO1997022975A2/en
Publication of WO1997022975A3 publication Critical patent/WO1997022975A3/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G21NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21FPROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/28Treating solids
    • G21F9/30Processing
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/36Processes yielding slags of special composition
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/001Dry processes
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/04Working-up slag
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/20Recycling

Definitions

  • the invention relates to a method for recycling metal parts which are radioactively contaminated, the metal parts being melted and a slag former being added, thereby forming a liquid melt and a slag which is then separated from the melt.
  • scrap contaminated, metallic, in particular iron-containing, scrap which must be recycled or disposed of. It is common to subject this scrap to melt decontamination.
  • the scrap is e.g. radioactively contaminated by ⁇ -emitters such as uranium, thorium, transurans and / or alkaline earth metals.
  • a method comprising melt decontamination is known from DE 33 18 377 AI. This process provides that the contaminated metal is melted. A slag former or slagging agent is then added to the melt. Then a slag forms that floats on the melt. Since the solubility of the substances which caused the radioactive contamination of the metal parts in the slag is greater than in the melt, the majority of the substances get into the slag. This results in a melt with a significantly reduced admixture of these substances. After it can no longer absorb any substances, the slag can be drawn off from the surface of the melt, and the melt which has been decontaminated as far as possible remains. The volume of the slag is only a small part of the total volume of the melt and slag.
  • the invention is based on the object of specifying a method for recycling radioactive contaminated metal parts which frees the metal parts even more than before from the substances which have caused their radioactive contamination.
  • the object is achieved according to the invention in that after the slag has been separated off, as long as the melt is still liquid, slag formers are again added to the liquid melt, and then the slag which is formed again is separated from the melt.
  • the process according to the invention is thus characterized in that a second addition of slag former and a second separation of slag follow a first addition of slag former and a first separation of slag in two stages.
  • the process according to the invention achieves the advantage that the melt remaining after the process has been carried out and thus also the shaped bodies formed from the melt contain significantly fewer residues of radioactive substances than was previously customary after melt decontamination.
  • the remaining melt and thus the shaped pieces formed from it can advantageously be used largely without restrictions.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Metallurgy (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Processing Of Solid Wastes (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

The invention relates to a process for using metal parts which are radioactively contaminated during which the metal parts are melted down. A slag former is added thereby forming a liquid melt and a slag. The slag is subsequently separated from the melt. This process is characterized in that after separation of the slag the slag former is added to the melt again as long as it is still liquid and that the formed slag is once more separated from the melt.

Description

Beschreibungdescription

Verfahren zur Verwertung kontaminierter MetallteileProcess for recycling contaminated metal parts

Die Erfindung betrifft ein Verfahren zur Verwertung von Me¬ tallteilen, die radioaktiv kontaminiert sind, wobei die Me¬ tallteile aufgeschmolzen werden und ein Schlackebildner zuge¬ geben wird, wodurch sich eine flüssige Schmelze und eine Schlacke bilden, die dann von der Schmelze abgetrennt wird.The invention relates to a method for recycling metal parts which are radioactively contaminated, the metal parts being melted and a slag former being added, thereby forming a liquid melt and a slag which is then separated from the melt.

Beim Abbau und auch beim Betrieb kerntechnischer Anlagen fällt in großem Umfang kontaminierter, metallischer, insbe¬ sondere eisenhaltiger, Schrott an, der verwertet oder besei¬ tigt werden muß. Eε ist üblich, diesen Schrott einer Schmelz- dekontamination zu unterziehen. Der Schrott ist z.B. durch α- Strahler, wie Uran, Thorium, Transurane und/oder Erdalkalime¬ talle radioaktiv kontaminiert.During the dismantling and also in the operation of nuclear plants, there is a large amount of contaminated, metallic, in particular iron-containing, scrap which must be recycled or disposed of. It is common to subject this scrap to melt decontamination. The scrap is e.g. radioactively contaminated by α-emitters such as uranium, thorium, transurans and / or alkaline earth metals.

Ein Verfahren, das eine Schmelzdekontamination umfaßt, ist aus der DE 33 18 377 AI bekannt. Dieses Verfahren sieht vor, daß das kontaminierte Metall aufgeschmolzen wird. Der Schmelze wird dann ein Schlackebildner oder Verschlackungs- mittel zugesetzt. Danach bildet sich eine Schlacke, die auf der Schmelze schwimmt. Da die Löslichkeit der Stoffe , die die radioaktive Kontamination der Metallteile verursacht ha¬ ben, in der Schlacke größer ist als in der Schmelze, gelangt der größte Teil der Stoffe in die Schlacke. Dadurch bedingt erhält man eine Schmelze mit einer deutlich verringerten Bei¬ mengung dieser Stoffe. Die Schlacke kann, nachdem sie keine Stoffe mehr aufnehmen kann, von der Oberfläche der Schmelze abgezogen werden, und es verbleibt die soweit wie möglich de¬ kontaminierte Schmelze. Das Volumen der Schlacke ist nur ein kleiner Teil des Gesamtvolumens aus Schmelze und Schlacke. Nur dieseε kleine Volumen muß einem Endlager zugeführt wer- den. Man benötigt also nur eine relativ kleine Endlagerkapa¬ zität . Bisher war es bereits üblich, die nach dem Abzug der Schlacke verbleibende Metallschmelze weiter zu verwenden. Es wurden beispielsweise Metallformstücke hergestellt. Solche Metallformstücke durften wegen der nach Durchführung der Schmelzdekontamination verbleibenden restlichen Radioak- tiviät aber nicht in allen Bereichen eingesetzt werden. In der Regel wurden solche Formstücke nur in kerntechnischen An¬ lagen verwendet.A method comprising melt decontamination is known from DE 33 18 377 AI. This process provides that the contaminated metal is melted. A slag former or slagging agent is then added to the melt. Then a slag forms that floats on the melt. Since the solubility of the substances which caused the radioactive contamination of the metal parts in the slag is greater than in the melt, the majority of the substances get into the slag. This results in a melt with a significantly reduced admixture of these substances. After it can no longer absorb any substances, the slag can be drawn off from the surface of the melt, and the melt which has been decontaminated as far as possible remains. The volume of the slag is only a small part of the total volume of the melt and slag. Only this small volume has to be sent to a repository. So you only need a relatively small repository capacity. So far it has been common to continue to use the molten metal remaining after the slag has been removed. For example, metal fittings were made. However, such metal fittings were not allowed to be used in all areas because of the remaining radioactivity remaining after the melt decontamination had been carried out. As a rule, such fittings were only used in nuclear facilities.

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zur Verwertung von radioaktiv kontaminierten Metallteilen anzuge¬ ben, das die Metallteile noch weitgehender als bisher von den Stoffen befreit, die ihre radioaktive Kontamination verur- sacht haben.The invention is based on the object of specifying a method for recycling radioactive contaminated metal parts which frees the metal parts even more than before from the substances which have caused their radioactive contamination.

Die Aufgabe wird nach der Erfindung dadurch gelöst, daß nach dem Abtrennen der Schlacke, solange die Schmelze noch flüssig ist, zur flüsεigen Schmelze erneut Schlackebildner zugegeben wird, und daß dann erneut gebildete Schlacke von der Schmelze abgetrennt wird.The object is achieved according to the invention in that after the slag has been separated off, as long as the melt is still liquid, slag formers are again added to the liquid melt, and then the slag which is formed again is separated from the melt.

Das Verfahren nach der Erfindung zeichnet sich also dadurch aus, daß in zwei Stufen auf eine erste Zugabe von Schlacke- bildner und ein erstes Abtrennen von Schlacke eine zweite Zu¬ gabe von Schlackebildner und ein zweites Abtrennen von Schlacke folgt.The process according to the invention is thus characterized in that a second addition of slag former and a second separation of slag follow a first addition of slag former and a first separation of slag in two stages.

Es wird dabei darauf geachtet, daß die Schmelze zwischen dem ersten Abtrennen von Schlacke und der zweiten Zugabe vonCare is taken to ensure that the melt between the first removal of slag and the second addition of

Schlackebildner flüssig bleibt. Das ist energetisch vorteil¬ haft. Würde nämlich die Schmelze, nachdem zum erεten Mal eine Schlacke entfernt worden ist, ganz oder nur teilweise erstar¬ ren, müßte zum erneuten Zugeben von Schlackebildner die er- starrte Schmelze wieder aufgeschmolzen werden. Überraschenderweise hat sich herausgeεtellt, daß nach der Durchführung eineε Schmelzdekontaminationsprozesεeε, bedingt durch die dann erfolgende erneute Zugabe von Schlackebildner in die verbleibende Schmelze, auch derjenige Anteil derSlag generator remains liquid. This is energetically advantageous. If the melt solidified completely or only partially after a slag had been removed for the first time, the solidified melt would have to be melted again to add slag formers again. Surprisingly, it has been found that after carrying out a melt decontamination process, due to the subsequent addition of slag formers into the remaining melt, that portion of the

Stoffe, die die Kontamination verurεacht haben, bei der er¬ neuten Schlackebildung in die Schlacke gelangt, welcher bei der früheren Schlackebildung in der Schmelze verblieben war.Substances that caused the contamination get into the slag during the new slag formation which remained in the melt during the previous slag formation.

Mit dem Verfahren in zwei Stufen wird eine größere MengeUsing the two-step process will result in a larger amount

(Masse oder Volumen) der radioaktiven Stoffe von der Schmelze abgetrennt als mit dem bekannten Einstufenverfahren bei glei¬ chem Einsatz von Schlackebildner.(Mass or volume) of the radioactive substances separated from the melt than with the known one-step process with the same use of slag formers.

Mit dem Verfahren nach der Erfindung wird der Vorteil er¬ zielt, daß die nach Durchführung des Verfahrens verbleibende Schmelze und damit auch aus der Schmelze gebildete Formkörper deutlich weniger Reste radioaktiver Stoffe enthalten als es bisher nach einer Schmelzdekontamination üblich war. Die verbleibende Schmelze und damit die aus ihr gebildeten Formstücke können vorteilhafterweise weitgehend ohne Ein¬ schränkungen verwendet werden. The process according to the invention achieves the advantage that the melt remaining after the process has been carried out and thus also the shaped bodies formed from the melt contain significantly fewer residues of radioactive substances than was previously customary after melt decontamination. The remaining melt and thus the shaped pieces formed from it can advantageously be used largely without restrictions.

Claims

Patentansprüche claims 1. Verfahren zur Verwertung von Metallteilen, die radioaktiv kontaminiert sind, wobei die Metallteile aufgeschmolzen wer- den und ein Schlackebildner zugegeben wird, wodurch εich eine flüssige Schmelze und eine Schlacke bilden, die dann von der Schmelze abgetrennt wird, d a d u r c h g e k e n n z e i c h n e t , daß nach dem Abtrennen der Schlacke, solange die Schmelze noch flüssig ist, zur flüssigen Schmelze erneut Schlackebildner zugegeben wird, und daß dann erneut gebildete Schlacke von der Schmelze abgetrennt wird. 1. A process for the recycling of metal parts which are radioactively contaminated, the metal parts being melted and a slag former being added, as a result of which a liquid melt and a slag are formed which are then separated from the melt, characterized in that after the separation the slag, as long as the melt is still liquid, slag former is again added to the liquid melt, and that slag which has formed again is then separated off from the melt.
PCT/DE1996/002309 1995-12-18 1996-12-02 Process for using contaminated metal parts Ceased WO1997022975A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU18681/97A AU1868197A (en) 1995-12-18 1996-12-02 Process for using contaminated metal parts

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1995147298 DE19547298A1 (en) 1995-12-18 1995-12-18 Process for recycling contaminated metal parts
DE19547298.5 1995-12-18

Publications (2)

Publication Number Publication Date
WO1997022975A2 true WO1997022975A2 (en) 1997-06-26
WO1997022975A3 WO1997022975A3 (en) 1997-08-14

Family

ID=7780483

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1996/002309 Ceased WO1997022975A2 (en) 1995-12-18 1996-12-02 Process for using contaminated metal parts

Country Status (4)

Country Link
AU (1) AU1868197A (en)
DE (1) DE19547298A1 (en)
WO (1) WO1997022975A2 (en)
ZA (1) ZA9610579B (en)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3318377C2 (en) * 1983-05-20 1986-05-15 Deutsche Gesellschaft für Wiederaufarbeitung von Kernbrennstoffen mbH, 3000 Hannover Process for the decontamination of radioactively contaminated iron and / or steel scrap
JPS60129698A (en) * 1983-12-19 1985-07-10 株式会社日立製作所 Method of melting and decontaminating radioactivity contaminated metal
GB2272566B (en) * 1992-11-17 1996-01-24 Clyde Shaw Ltd Decontamination method
US5640710A (en) * 1994-11-25 1997-06-17 Doryokuro Kakunenryo Kaihatsu Jigyodan Method for melt-decontaminating metal contaminated with radioactive substance
FR2730091A1 (en) * 1995-02-01 1996-08-02 Commissariat Energie Atomique DECONTAMINATION OF ZIRCALOY USING A SLAG BY A COLD CRUCIBLE MELTING OPERATION WITH CONTINUOUS LINGOT DRAWING

Also Published As

Publication number Publication date
ZA9610579B (en) 1997-06-18
AU1868197A (en) 1997-07-14
DE19547298A1 (en) 1997-06-19
WO1997022975A3 (en) 1997-08-14

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