WO2000017894A1 - Method for reusing permanent magnets - Google Patents

Method for reusing permanent magnets Download PDF

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Publication number
WO2000017894A1
WO2000017894A1 PCT/DE1999/003077 DE9903077W WO0017894A1 WO 2000017894 A1 WO2000017894 A1 WO 2000017894A1 DE 9903077 W DE9903077 W DE 9903077W WO 0017894 A1 WO0017894 A1 WO 0017894A1
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WO
WIPO (PCT)
Prior art keywords
magnetic material
permanent magnets
separation
action
magnetic
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PCT/DE1999/003077
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German (de)
French (fr)
Inventor
Georg-Werner Reppel
Lothar Zapf
Rolf Blank
Eberhard Adler
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Vacuumschmelze Gmbh
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Publication of WO2000017894A1 publication Critical patent/WO2000017894A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/0553—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 obtained by reduction or by hydrogen decrepitation or embrittlement
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0573—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes obtained by reduction or by hydrogen decrepitation or embrittlement

Definitions

  • the invention relates to a method for reusing permanent magnets by separating the magnetic material from a composite body and reusing the obtained magnetic material for the production of brand-new magnetic materials.
  • Technical products in particular waste from technical products, such as Televisions, HIFI systems, computers, monitors, peripheral devices, for reusing their individual components or the manufacturing materials can be reused or recycled.
  • These technical products represent composite bodies made of various individual materials, which to a certain extent are magnetic material, such as. B. Nd-Fe-B included.
  • loudspeakers are known from US Pat. No. 5,390,257 which contain permanent magnets made of rare earths. These loudspeakers are characterized by high efficiency and low weight.
  • the recycling of rare earths from chemical compounds containing rare earths can be done according to the US Perform 5,437,709 chemically by liquid metal extraction.
  • the process requires complex equipment for distilling off the rare earths from a metal melt obtained during the separation. It is not possible, for example with Nd-Fe-B magnetic material, to recover the other elements Fe and B at the same time.
  • the object of the present invention is to provide a method for reusing permanent magnets which can be carried out in a simple and cost-saving manner.
  • Another object of the invention is to provide a method for separating magnetic material from composite bodies, which can be carried out on a large industrial scale in a particularly simple manner.
  • Composite body according to the invention are in general technical 'see products that contain other materials in addition to the magnetic material.
  • Examples of composite bodies according to the invention are loudspeakers, motors, monitors, television sets, HIFI systems, computers, peripheral devices, etc.
  • magnetic material very generally includes magnetic materials which consist of a permanent magnet and / or a soft magnet, it being possible for the method of the invention to separate the magnetic material from the adhering non-magnetic materials.
  • the permanent magnet material which can be separated according to the invention preferably contains rare earths.
  • rare earths which can be used according to the invention are Nd, Pr, Ce, Sm and Dy.
  • the magnetic material which can be separated off according to the invention preferably also contains the elements Fe, Co or B.
  • the proportion in which the rare earths, Fe, Co or B are present in the magnetic material depends on the type and purity of the magnetic material.
  • the magnetic material that can be used according to the invention particularly preferably contains phases of the structural formulas Nd2Fei4B, S1T1C05, or Srri2 (Co, Fe, Cu, Zr) ] _7.
  • other elements suitable for permanent magnets may also be present in the permanent magnets.
  • Permanent magnets which consist essentially of Nd 2 -Fei-B can be very particularly preferably reused. Examples of further permanent magnet materials which can be used according to the invention are known from EP-B-0 153 744.
  • the magnetic material is separated from the composite body under the action of a gaseous material.
  • the gaseous material used is preferably hydrogen.
  • the gaseous material preferably acts at a temperature in the range from 20 ° C (room temperature) to 850 ° C and one Pressure (absolute) from 0.1 bar to 150 bar on the magnetic material.
  • thermal treatment can expediently take place at a temperature which is at least equal to the Curie temperature of the permanent magnet. This treatment is preferably of demagnetization of the permanent magnet '' lind facilitates the separation of different materials.
  • the gaseous material can be removed, for example for recovery.
  • This is preferably carried out by means of a temperature treatment at a temperature in the range from 200 to 850 ° C., this temperature treatment preferably being carried out under a vacuum or an inert gas atmosphere.
  • the 400 to 600 ° C. limits are particularly preferred as the temperature range during removal.
  • the removal of the gaseous material such as. B. hydrogen, the powder metallurgical production of a new permanent magnet from the recycled material facilitated.
  • a magnetic material can be obtained which contains a small amount of hydrogen. This leads to good magnetic properties and good corrosion stability.
  • the temperature treatments described above can be carried out, for example, in a resistance-heated closed furnace known per se, a continuous furnace or in a rotary tube furnace known per se.
  • a mechanical action on the composite body is carried out with a gaseous material during the separation according to the invention.
  • This mechanical action can take place by means of conventional comminution methods, such as grinding, hammering or jaw breaking.
  • the separation of the various constituents can expediently be carried out by known separation processes such as sieving, sifting or magnetic or eddy current separation.
  • the re-use of the magnetic material obtained can be carried out in such a way that the magnetic material obtained is used as the starting material during the known production of brand-new magnetic materials. However, it is expedient that the magnetic material obtained is added to fresh starting material in certain portions.
  • a rough separation of the magnetic material from the products can first be carried out by mechanical action, for example according to the method known from US Pat. No. 5,678,773. This also expediently separates plastics and metals.
  • the often very strongly magnetized permanent magnets can preferably be demagnetized before comminution, which is possible, for example, by heating the products above the Curie temperature in air or with the exclusion of air (pyrolysis).
  • the permanent magnets are fixed in the product with adhesives, or a magnetic iron yoke is attached to the permanent magnet by gluing. After mechanical separation or shredding, the adhesive residues can be removed from the magnets.
  • Known chemical solvents can be used to separate adhering adhesives.
  • An alternative procedure can be to separate the adhesive residues from the permanent magnets by means of an annealing treatment with exclusion of air (pyrolysis). The method according to the invention can be carried out particularly expediently without such a step for separating adhering adhesives.
  • a particular advantage of the method according to the invention is that the relatively expensive magnetic material can be recovered from the composite in almost powder form, so that it can be powder metallurgically processed to new magnets of high quality without or with a small number of additional process steps.
  • a further advantage is that when the method according to the invention is carried out, a high yield can be achieved in the recovery of the expensive magnetic material.
  • a loudspeaker for audio or video equipment which is to be recycled, from a disk-shaped Nd-Fe-B-
  • Permanent magnets a ferromagnetic yoke in the form of an iron pot and an iron plate, as well as a Cu coil, and a loudspeaker basket with a membrane, the disk-shaped permanent magnet having a mass of 7.1 g, is subjected to a multi-stage thermal treatment: a) glowing under Argon atmosphere 1 h at 350 ° C (above the Curie temperature of the permanent magnet). Organic components of the loudspeaker are pyrolyzed and the permanent magnet demagnetized. b) cooling to room temperature, then holding the loudspeakers under hydrogen gas at a pressure of 1 bar for a period of 2 h.
  • the Nd-Fe-B alloy absorbs hydrogen and becomes brittle, so that the permanent magnet breaks down into a powder.
  • the coarse components preferably consist of metallic parts such as the iron pot; Magnetic separation can further separate ferro- and non-magnetic coarse components.
  • the powder thus obtained consists of 32.3% of rare earths (Nd, Pr, Dy), 1.0% of B and 66.7% of Fe.
  • Nd-Fe-B magnet An average of 6.8 g of the Nd-Fe-B magnet is recovered, which corresponds to a yield of 95.8%. f) Grinding, sieving and mixing the material obtained with Nd-Fe-B powder of suitable composition, pressing into shaped parts and sintering in the powder metallurgy production method known per se for the production of new Nd-Fe-B magnets.
  • the permanent magnet material is separated immediately after the embrittlement treatment.
  • a granular or powdery material is obtained which contains 93.8% of the magnetic alloy.
  • the loudspeakers which contain permanent magnets of the Nd-Fe-B type, are kept in a vacuum container under a hydrogen atmosphere of 1 bar at room temperature for 3 hours. The membranes are then removed mechanically and the loudspeakers are moved on a vibrating sieve with a mesh size of 10 mm for 30 minutes. The separated portion ( ⁇ 5 mm) contains the Nd-Fe-B alloy to 88.2%.
  • Example 4
  • a scrap contains permanent magnets of the type Nd-Fe-B and the type Sm-Co in an unknown ratio.
  • the permanent magnets are glued to ceramic plates.
  • the composite bodies are kept in a hydrogen atmosphere of 1 bar at room temperature for 3 hours. After sieving on a vibrating screen, the magnets can be completely removed from part of the composite bodies. In the screened portion, the Sm content is ⁇ 0.3% and the Nd content is 32.1%, so that a complete separation of the magnet types has been achieved.
  • the remaining composite plates with permanent magnets are subjected to annealing under hydrogen 1 bar at 850 ° C. After cooling to room temperature, the permanent magnets are separated from the ceramic plates.
  • a chemical analysis shows that the permanent magnets are all made of Sm-Co magnets; the Nd content is ⁇ 0.1%.
  • the recycled Sm-Co magnets can be easily ground into powder. By adding fresh Sm-Co alloy, it is possible to produce full-fledged Sm-Co magnets again.

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

The invention relates to a method for reusing permanent magnets which comprises the following steps: separation of the magnetic material from a composite body through the action of a gaseous material which embrittles the magnetic material, where the composite body before and/or during and/or after the action of the gaseous material is possibly subjected to a mechanical force which supports the separation process; reuse of the magnetic material obtained in this way for the production of new permanent magnets.

Description

Beschreibungdescription
Verfahren zur Wiederverwendung von DauermagnetenProcess for reusing permanent magnets
Die Erfindung betrifft ein Verfahren zur Wiederverwendung von Dauermagneten durch Trennung des Magnet aterials von einem Verbundkotper und Wiederverwendung des gewonnen Magnetmaterials zur Herstellung von fabrikneuen Magnetmateπalien .The invention relates to a method for reusing permanent magnets by separating the magnetic material from a composite body and reusing the obtained magnetic material for the production of brand-new magnetic materials.
In zunehmendem Maße müssen technische Produkte, insbesondere Abfall von technischen Produkten, wie z.B. Fernsehgeräte, HIFI-Anlagen, Computer, Monitore, Peripheriegerate, zur Wiederverwendung ihrer Einzelkomponenten bzw. der Herstellungsmaterialien wiederverwendet, bzw. rezyklisiert werden. Diese technischen Produkte stellen Verbundkorper aus verschiedene- nen Einzelmatenalien dar, welche zu einem gewissen Teil Ma- gnetmaterial, wie z. B. Nd-Fe-B, enthalten.Technical products, in particular waste from technical products, such as Televisions, HIFI systems, computers, monitors, peripheral devices, for reusing their individual components or the manufacturing materials can be reused or recycled. These technical products represent composite bodies made of various individual materials, which to a certain extent are magnetic material, such as. B. Nd-Fe-B included.
So sind beispielsweise aus der US 5,390,257 Lautsprecher be- kannt, die Dauermagneten aus Seltenen Erden enthalten. Diese Lautsprecher zeichnen sich durch einen hohen Wirkungsgrad bei geringem Gewicht aus.For example, loudspeakers are known from US Pat. No. 5,390,257 which contain permanent magnets made of rare earths. These loudspeakers are characterized by high efficiency and low weight.
Bekanntlich ist zur Wieαerverwendung eines Materials üie Ab- trennung des wiederzuverwendenden Emzelmaterials vom Aus- gangsmaterial notwendig.As is known, it is necessary to reuse a material by separating the reusable material from the starting material.
In großtechnischem Maßstab wird Abfall häufig vor der Weiterverarbeitung zerkleinert. Ein Verfahren zur Zerkleinerung ist aus der US 5,678,773 bekannt. Das beschriebenen Verfahren ermöglicht die Trennung von Metallen und Kunststoffen durch mechanische Verfahren. Bei Magnetsystemen ist jedoch eine Trennung des magnetisierten Dauermagneten von den Eisenteilen mit dieser Methode nicht möglich.On an industrial scale, waste is often shredded before further processing. A method for comminution is known from US 5,678,773. The process described enables the separation of metals and plastics by mechanical processes. With magnet systems, however, it is not possible to separate the magnetized permanent magnet from the iron parts with this method.
Die Rezyklisierung von Seltenen Erden aus chemischen Verbindungen, die Seltene Erden enthalten, laßt sich gemäß der US 5,437,709 auf chemischem Wege durch Flüssigmetall-Extraktion durchführen. Das Verfahren benötigt eine aufwendige Apparatur zum Abdestillieren der Seltenen Erden von einer bei der Trennung anfallenden Metallschmelze. Es bietet keine Möglichkeit, beispielsweise bei Nd-Fe-B Magnetmaterial, gleichzeitig auch die übrigen Elemente Fe und B zurückzugewinnen.The recycling of rare earths from chemical compounds containing rare earths can be done according to the US Perform 5,437,709 chemically by liquid metal extraction. The process requires complex equipment for distilling off the rare earths from a metal melt obtained during the separation. It is not possible, for example with Nd-Fe-B magnetic material, to recover the other elements Fe and B at the same time.
Es besteht demnach immer noch der Bedarf nach einem einfach durchführbaren Verfahren zur Abtrennung eines Magnetmaterials von Verbundkörpern.Accordingly, there is still a need for an easy to carry out process for separating a magnetic material from composite bodies.
Die Aufgabe der vorliegenden Erfindung besteht darin, ein Verfahren zur Wiederverwendung von Dauermagneten anzugeben, welches einfach und kostensparend durchführbar ist. Eine wei- tere Aufgabe der Erfindung ist die Bereitstellung eines Verfahrens zur Abtrennung von Magnetmaterial von Verbundkörpern, welches sich auf besonders einfache Weise großtechnisch durchführen läßt.The object of the present invention is to provide a method for reusing permanent magnets which can be carried out in a simple and cost-saving manner. Another object of the invention is to provide a method for separating magnetic material from composite bodies, which can be carried out on a large industrial scale in a particularly simple manner.
Diese Aufgabe wird erfindungsgemäß gelöst durch ein Verfahren zur Wiederverwendung von Dauermagneten, welches die folgenden Schritte umfaßt:This object is achieved according to the invention by a method for reusing permanent magnets, which comprises the following steps:
Abtrennung des Magnetmaterials von einem Verbundkörper unter Einwirkung eines gasförmigen Materials, welches das Magnetmaterial durch dessen Einwirkung versprödet wobei ggf. vor und/oder während und/oder nach der Einwirkung des gasförmigen Materials eine mechanische Einwirkung auf den Verbundkörper erfolgt, welche den Vorgang der Abtrennung unterstützt, - Wiederverwendung des gewonnen Magnetmaterials zur Herstellung von fabrikneuen Dauermagneten.Separation of the magnetic material from a composite body under the action of a gaseous material which embrittles the magnetic material due to its action, where appropriate before and / or during and / or after the action of the gaseous material there is a mechanical action on the composite body which supports the separation process , - Reuse of the obtained magnetic material for the production of brand new permanent magnets.
Das Magnetmaterial wird somit aufgrund der Versprödung vom Verbundkörper bzw. von den am Magnetmaterial anhaftenden Ma- terialien abgetrennt. Verbundkörper gemäß der Erfindung sind ganz allgemein techni-' sehe Produkte, die neben anderen Materialien Magnetmaterial enthalten. Beispiele für erfindungsgemäße Verbundkörper sind Lautsprecher, Motore, Monitore, Fernsehgeräte, HIFI-Anlagen, Computer, Peripheriegeräte usw.The magnetic material is thus separated from the composite body or from the materials adhering to the magnetic material due to embrittlement. Composite body according to the invention are in general technical 'see products that contain other materials in addition to the magnetic material. Examples of composite bodies according to the invention are loudspeakers, motors, monitors, television sets, HIFI systems, computers, peripheral devices, etc.
Unter den*-Begriff „Magnetmaterial" fallen ganz allgemein magnetische Materialien, die aus einem Dauermagneten und/oder einem Weichmagneten bestehen, wobei sich mit dem Verfahren der Erfindung das Magnetmaterial von den anhaftenden nicht magnetischen Materialien trennen lassen muß.The * term "magnetic material" very generally includes magnetic materials which consist of a permanent magnet and / or a soft magnet, it being possible for the method of the invention to separate the magnetic material from the adhering non-magnetic materials.
Das erfindungsgemäß abtrennbare Dauermagnetmaterial enthält vorzugsweise Seltene Erden. Beispiele für erfindungsgemäß einsetzbare Seltene Erden sind Nd, Pr, Ce, Sm und Dy. Bevorzugt enthält das erfindungsgemäß abtrennbare Magnetmaterial neben Seltenen Erden noch die Elemente Fe, Co oder B. Der Mengenanteil, in dem die Seltenen Erden, Fe, Co oder B im Magnetmaterial vorliegen, richtet sich nach Art und Reinheit des Magnetmaterials. Das erfindungsgemäß einsetzbare Magnetmaterial enthält besonders bevorzugt Phasen der Strukturformeln Nd2Fei4B, S1T1C05, oder Srri2 (Co, Fe, Cu, Zr)]_7. In den Dauermagneten können neben den genannten Elementen noch andere für Dauermagnete geeignete Elemente vorhanden sein.The permanent magnet material which can be separated according to the invention preferably contains rare earths. Examples of rare earths which can be used according to the invention are Nd, Pr, Ce, Sm and Dy. In addition to rare earths, the magnetic material which can be separated off according to the invention preferably also contains the elements Fe, Co or B. The proportion in which the rare earths, Fe, Co or B are present in the magnetic material depends on the type and purity of the magnetic material. The magnetic material that can be used according to the invention particularly preferably contains phases of the structural formulas Nd2Fei4B, S1T1C05, or Srri2 (Co, Fe, Cu, Zr) ] _7. In addition to the elements mentioned, other elements suitable for permanent magnets may also be present in the permanent magnets.
Ganz besonders bevorzugt lassen sich Dauermagnete wiederverwenden, die im wesentlichen aus Nd2-Fei-B bestehen. Beispiele für weitere erfindungsgemäß einsetzbare Dauermagnetmaterialien sind aus der EP-B-0 153 744 bekannt.Permanent magnets which consist essentially of Nd 2 -Fei-B can be very particularly preferably reused. Examples of further permanent magnet materials which can be used according to the invention are known from EP-B-0 153 744.
Die Abtrennung des Magnetmaterials vom Verbundkörper erfolgt unter Einwirkung eines gasförmigen Materials. Vorzugsweise handelt es sich bei dem eingesetzten gasförmigen Material um Wasserstoff.The magnetic material is separated from the composite body under the action of a gaseous material. The gaseous material used is preferably hydrogen.
Das gasförmige Material wirkt bevorzugt bei einer Temperatur im Bereich von 20°C (Raumtemperatur) bis 850 °C und einem Druck (absolut) von 0,1 bar bis 150 bar auf das Magnetmaterial ein. Vor und während der Behandlung mit dem versprödenden gasförmigen Material kan zweckmäßigerweise, eine thermische Behandlung bei einer Temperatur erfolgen, die mindestens gleich der Curie-Temperatur des Dauermagneten ist. Diese Behandlung dient vorzugsweise der Entmagnetisierung des Dauermagneten ''lind erleichtert die Abtrennung verschiedener Materialien.The gaseous material preferably acts at a temperature in the range from 20 ° C (room temperature) to 850 ° C and one Pressure (absolute) from 0.1 bar to 150 bar on the magnetic material. Before and during the treatment with the embrittling gaseous material, thermal treatment can expediently take place at a temperature which is at least equal to the Curie temperature of the permanent magnet. This treatment is preferably of demagnetization of the permanent magnet '' lind facilitates the separation of different materials.
Bereits während oder vorzugsweise nach der Versprödung kann eine Entfernung, beispielsweise zur Wiedergewinnung, des gasförmigen Materials durchgeführt werden. Dies erfolgt vorzugsweise mittels einer Temperaturbehandlung bei einer Temperatur im Bereich von 200 bis 850 °C, wobei diese Temperaturbehand- lung bevorzugt unter Vakuum oder einer Edelgas-Atmosphäre durchgeführt wird. Als Temperaturbereich bei der Entfernung sind die Grenzen 400 bis 600 °C besonders bevorzugt. Im Falle des dauermagnetischen Materials beispielsweise auf Basis der Legierung Nd-Fe-B wird durch die Entfernung des gasförmigen Materials wie z. B. Wasserstoff, die pulvermetallurgische Herstellung eines neuen Dauermagneten aus dem rezyklierten Material erleichtert. Hierdurch läßt sich ein Magnetmaterial erhalten, welches einen geringen Anteil Wasserstoff enthält. Dies führt zu guten Magneteigenschaften und guter Korrosions- Stabilität.Already during or preferably after embrittlement, the gaseous material can be removed, for example for recovery. This is preferably carried out by means of a temperature treatment at a temperature in the range from 200 to 850 ° C., this temperature treatment preferably being carried out under a vacuum or an inert gas atmosphere. The 400 to 600 ° C. limits are particularly preferred as the temperature range during removal. In the case of the permanent magnetic material, for example based on the alloy Nd-Fe-B, the removal of the gaseous material such as. B. hydrogen, the powder metallurgical production of a new permanent magnet from the recycled material facilitated. As a result, a magnetic material can be obtained which contains a small amount of hydrogen. This leads to good magnetic properties and good corrosion stability.
Die vorstehend beschriebenen Temperaturbehandlungen lassen sich beispielsweise in einem an sich bekannten widerstandsbeheizten geschlossenen Ofen, einem Durchlaufofen oder in einem an sich bekannten Drehrohr-Ofen durchführen.The temperature treatments described above can be carried out, for example, in a resistance-heated closed furnace known per se, a continuous furnace or in a rotary tube furnace known per se.
In einer weiteren bevorzugten Ausführungsform wird während der erfindungsgemäßen Abtrennung mit einem gasförmigen Material eine mechanische Einwirkung auf den Verbundkörper durch- geführt. Diese mechanische Einwirkung kann durch übliche Zerkleinerungsmethoden, wie Mahlen, Hämmern oder Backenbrechen erfolgen. Die Trennung der verschiedenen Bestandteile laßt sich zweckmäßig durch an sich bekannte Separationsverfahren wie Sieben, Sichten oder Magnet- bzw. Wirbelstromseparation durchfuhren.In a further preferred embodiment, a mechanical action on the composite body is carried out with a gaseous material during the separation according to the invention. This mechanical action can take place by means of conventional comminution methods, such as grinding, hammering or jaw breaking. The separation of the various constituents can expediently be carried out by known separation processes such as sieving, sifting or magnetic or eddy current separation.
Die Wiederverwendung des gewonnen Magnetmaterials kann m der Weise durchgeführt werden, daß das gewonnene Magnetmaterial wahrend det an sich bekannten Fertigung von fabrikneuen Ma- gnetmateπalien als Ausgangsmaterial eingesetzt wird. Zweck- maßig ist es allerdings, daß das gewonnene Magnetmaterial frischem Ausgangsmaterial m bestimmten Teilmengen zugesetzt wird.The re-use of the magnetic material obtained can be carried out in such a way that the magnetic material obtained is used as the starting material during the known production of brand-new magnetic materials. However, it is expedient that the magnetic material obtained is added to fresh starting material in certain portions.
Vor der Durchfuhrung des erfmdungsgemäßen Verfahrens kann zunächst eine grobe Trennung des Magnetmaterials von den Produkten durch mechanische Einwirkung, beispielsweise gemäß dem aus der US 5,678,773 bekannten Verfahren, durchgeführt werden. Hierbei erfolgt zweckmaßigerweise auch eine Separation von Kunststoffen und Metallen. Vorzugsweise können die häufig sehr stark magnetisierten Dauermagnete vor der Zerkleinerung noch entmagnetisiert werden, was beispielsweise durch eine Erhitzung der Produkte oberhalb der Curie-Temperatur an Luft oder unter Luftabschluß (Pyrolyse) möglich ist.Before carrying out the method according to the invention, a rough separation of the magnetic material from the products can first be carried out by mechanical action, for example according to the method known from US Pat. No. 5,678,773. This also expediently separates plastics and metals. The often very strongly magnetized permanent magnets can preferably be demagnetized before comminution, which is possible, for example, by heating the products above the Curie temperature in air or with the exclusion of air (pyrolysis).
In der Regel sind die Dauermagnete mit Klebstoffen im Produkt fixiert bzw. es ist ein magnetischer Ruckschluß aus Eisen durch Klebung am Dauermagneten befestigt. Nach der mechanischen Trennung bzw. Zerkleinerung können die Magnete von anhaftenden Klebstoffruckstanden befreit werden. Für die Abtrennung anhaftender Klebstoffe können an sich bekannte chemische Losungsmittel eingesetzt werden. Eine alternative Vor- gehensweise kann darin bestehen, eine zusätzliche Abtrennung der Klebstoffruckstande von den Dauermagneten mittels einer Gluhbehandlung unter Luftabschluß (Pyrolyse) vorzunehmen. Das erfmdungsgemaße Verfahren laßt sich besonders zweckmäßig ohne einen solchen Schritt zur Abtrennung von anhaftenden Klebstoffen durchfuhren. Ein besonderer Vorteil des erfmdungsgemaßen Verfahrens ist es, daß das relativ teure Magnetmaterial nahezu pulverformig aus dem Verbundkorper zurückgewonnen werden kann, so daß es ohne bzw. mit einer geringen Zahl zusätzliche Prozeßschritte wieder pulvermetallurgisch zu neuen Magneten hoher Qualltat verarbeitet werden kann. Außerdem ist es mit dem erfmdungsgemaßen Ve-rfahren möglich, durch geeignete Wahl der Ver- produngsbedmgungen verschiedene Dauermagnetlegierungen, z. B. als Schrotte, zu trennen.As a rule, the permanent magnets are fixed in the product with adhesives, or a magnetic iron yoke is attached to the permanent magnet by gluing. After mechanical separation or shredding, the adhesive residues can be removed from the magnets. Known chemical solvents can be used to separate adhering adhesives. An alternative procedure can be to separate the adhesive residues from the permanent magnets by means of an annealing treatment with exclusion of air (pyrolysis). The method according to the invention can be carried out particularly expediently without such a step for separating adhering adhesives. A particular advantage of the method according to the invention is that the relatively expensive magnetic material can be recovered from the composite in almost powder form, so that it can be powder metallurgically processed to new magnets of high quality without or with a small number of additional process steps. In addition, with the method according to the invention, it is possible to select various permanent magnet alloys, eg. B. as scrap to separate.
Ein weiterer Vorteil ist, daß bei Durchfuhrung des erfin- dungsgemaßen Verfahrens eine hohe Ausbeute bei der Ruckgewinnung des teuren Magnetmaterials erreicht werden kann.A further advantage is that when the method according to the invention is carried out, a high yield can be achieved in the recovery of the expensive magnetic material.
Nachfolgend werden Ausfuhrungsbeispiele beschrieben, die zur Erläuterung der Erfindung dienen.Exemplary embodiments are described below, which serve to explain the invention.
Beispiel 1 :Example 1 :
Ein Lautsprecher für Audio- oder Videogerate, welcher rezy- kliert werden soll, aus einem scheibenförmigen Nd-Fe-B-A loudspeaker for audio or video equipment, which is to be recycled, from a disk-shaped Nd-Fe-B-
Dauermagneten, einem ferromagnetischen Ruckschluß m Form eines Eisentopfes und einer Eisenplatte, sowie einer Cu-Spule, und einem Lautsprecherkorb mit einer Membran, wobei der scheibenförmige Dauermagnet eine Masse von 7,1 g hat, wird einer mehrstufigen thermischen Behandlung unterzogen: a) Gluhung unter Argon-Atmosphare 1 h bei 350°C (oberhalb der Curietemperatur des Dauermagneten) . Dabei werden organische Bestandteile des Lautsprechers pyrolysiert und der Dauermagnet entmagnetisiert. b) Abkühlung auf Raumtemperatur, anschließendes Halten der Lautsprecher unter Wasserstoffgas bei einem Druck von 1 bar für eine Zeit von 2 h. Dabei absorbiert die Nd-Fe-B-Legierung Wasserstoff und versprödet, so daß der Dauermagnet zu einem Pulver zerfallt. c) Gluhung der Lautsprechersysteme bei 450°C ca. 5 h unter Vakuum, bis ein Vakuum von 0,1 mbar erreicht ist. d) Sieben mit einem Sieb der Maschenweite 2 mm nach der ther-' mischen Behandlung zur Trennung der pulverförmigen Bestandteile von den massiven Bestandteilen. Die groben Bestandteile bestehen vorzugsweise aus metallischen Teilen wie dem Eisen- topf; durch Magnetspearation können ferro- und unmagnetische grobe Bestandteile weiter separiert werden. e) Sichtendes verbleibenden Pulvers zur Trennung von leichteren, meist nicht-metallischen Bestandteilen. Das so erhaltene Pulver besteht zu 32,3% aus Seltenen Erden (Nd, Pr, Dy) zu 1,0% aus B und zu 66,7% aus Fe . Es werden durchschnittlich 6,8 g des Nd-Fe-B-Magneten zurückgewonnen, was einer Ausbeute von 95,8% entspricht. f) Mahlen, Sieben und Mischen des erhaltenen Materials mit Nd-Fe-B-Pulver geeigneter Zusammensetzung, Pressen zu Form- teilen und Sintern in der an sich bekannten pulvermetallurgi- schen Herstellungsweise zur Herstellung neuer Nd-Fe-B- Magneten.Permanent magnets, a ferromagnetic yoke in the form of an iron pot and an iron plate, as well as a Cu coil, and a loudspeaker basket with a membrane, the disk-shaped permanent magnet having a mass of 7.1 g, is subjected to a multi-stage thermal treatment: a) glowing under Argon atmosphere 1 h at 350 ° C (above the Curie temperature of the permanent magnet). Organic components of the loudspeaker are pyrolyzed and the permanent magnet demagnetized. b) cooling to room temperature, then holding the loudspeakers under hydrogen gas at a pressure of 1 bar for a period of 2 h. The Nd-Fe-B alloy absorbs hydrogen and becomes brittle, so that the permanent magnet breaks down into a powder. c) Annealing the speaker systems at 450 ° C for about 5 hours under vacuum until a vacuum of 0.1 mbar is reached. d) sieving with a sieve of mesh size 2 mm after the thermal 'mix treatment for separating the pulverulent constituents of the solid ingredients. The coarse components preferably consist of metallic parts such as the iron pot; Magnetic separation can further separate ferro- and non-magnetic coarse components. e) Sifting the remaining powder to separate lighter, mostly non-metallic components. The powder thus obtained consists of 32.3% of rare earths (Nd, Pr, Dy), 1.0% of B and 66.7% of Fe. An average of 6.8 g of the Nd-Fe-B magnet is recovered, which corresponds to a yield of 95.8%. f) Grinding, sieving and mixing the material obtained with Nd-Fe-B powder of suitable composition, pressing into shaped parts and sintering in the powder metallurgy production method known per se for the production of new Nd-Fe-B magnets.
Beispiel 2Example 2
Es wird wie in Beispiel 1 vorgegangen, jedoch mit folgenden Unterschieden:The procedure is as in Example 1, but with the following differences:
Die Trennung des Dauermagnetmaterials erfolgt direkt nach der Versprödungsbehandlung. Es wird ein granulat- bzw. pulverför- miges Material erhalten, das die Magnetlegierung zu 93, 8% enthält .The permanent magnet material is separated immediately after the embrittlement treatment. A granular or powdery material is obtained which contains 93.8% of the magnetic alloy.
Beispiel 3:Example 3:
Die Lautsprecher, welche Dauermagnete des Typs Nd-Fe-B enthalten, werden in einem Vakuumbehälter unter einer Wasserstoffatmosphäre von 1 bar bei Raumtemperatur 3 h gehalten. Anschließend werden die Membranen mechanisch entfernt und die Lautsprecher auf einem Rüttelsieb mit einer Maschenweite von 10 mm 30 min lang bewegt. Der abgetrennte Anteil (< 5 mm) enthält die Nd-Fe-B-Legierung zu 88,2%. Beispiel 4 :The loudspeakers, which contain permanent magnets of the Nd-Fe-B type, are kept in a vacuum container under a hydrogen atmosphere of 1 bar at room temperature for 3 hours. The membranes are then removed mechanically and the loudspeakers are moved on a vibrating sieve with a mesh size of 10 mm for 30 minutes. The separated portion (<5 mm) contains the Nd-Fe-B alloy to 88.2%. Example 4:
Ein Schrott enthält Dauermagnete des Typs Nd-Fe-B und des Typs Sm-Co in unbekanntem Verhältnis. Die Dauermagnete sind auf Keramikplatten aufgeklebt. Die Verbundkörper werden 3 h in einer Wasserstoffatmosphäre von 1 bar bei Raumtemperatur gehalten .- ^ach Sieben auf einem Rüttelsieb können von einem Teil der Verbundkörper die Magnete vollständig entfernt werden. In dem abgesiebten Anteil beträgt der Sm-Gehalt <0,3% und der Nd-Gehalt 32,1%, so daß eine vollständige Trennung der Magnetsorten gelungen ist.A scrap contains permanent magnets of the type Nd-Fe-B and the type Sm-Co in an unknown ratio. The permanent magnets are glued to ceramic plates. The composite bodies are kept in a hydrogen atmosphere of 1 bar at room temperature for 3 hours. After sieving on a vibrating screen, the magnets can be completely removed from part of the composite bodies. In the screened portion, the Sm content is <0.3% and the Nd content is 32.1%, so that a complete separation of the magnet types has been achieved.
Die verbleibenden Verbundplatten mit Dauermagneten werden einer Glühung unter Wasserstoff 1 bar bei 850°C unterzogen. Nach Abkühlung auf Raumtemperatur sind die Dauermagnete von den Keramikplatten getrennt. Eine chemische Analyse ergibt, daß die Dauermagnete sämtlich aus Sm-Co-Magneten bestehen; der Nd-Gehalt beträgt <0,1%.The remaining composite plates with permanent magnets are subjected to annealing under hydrogen 1 bar at 850 ° C. After cooling to room temperature, the permanent magnets are separated from the ceramic plates. A chemical analysis shows that the permanent magnets are all made of Sm-Co magnets; the Nd content is <0.1%.
Die so rezyklierten Sm-Co-Magnete lassen sich leicht zu Pulver mahlen. Durch Zumischen von frischer Sm-Co-Legierung lassen sich wieder vollwertige Sm-Co-Magnete herstellen.The recycled Sm-Co magnets can be easily ground into powder. By adding fresh Sm-Co alloy, it is possible to produce full-fledged Sm-Co magnets again.
Alle Prozentangaben in den vorangegangenen Beispielen bezie- hen sich auf Gewichtsanteile in Bezug auf das Gesamtgewicht des Pulvermaterials. All percentages in the preceding examples relate to parts by weight in relation to the total weight of the powder material.

Claims

Patentansprüche claims
1. Verfahren zur Wiederverwendung von Dauermagneten umfassend die Schritte: - Abtrennung des Magnetmaterials von einem Verbundkörper unter Einwirkung eines gasförmigen Materials, welches das'ϊfagnetmaterial durch dessen Einwirkung versprödet wobei ggf. vor und/oder während und/oder nach der Einwirkung des gasförmigen Materials eine mechanische Ein- Wirkung auf den Verbundkörper erfolgt, welche den Vorgang der Abtrennung unterstützt,1. A method for reusing permanent magnets comprising the steps: - Separation of the magnetic material from a composite body under the action of a gaseous material which embrittles the magnetic material by its action, possibly before and / or during and / or after the action of the gaseous material there is mechanical action on the composite body, which supports the process of separation,
Wiederverwendung des gewonnen Magnetmaterials zur Herstellung von fabrikneuen Dauermagneten.Reuse of the obtained magnetic material for the production of brand new permanent magnets.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß das Magnetmaterial ein Dauermagnetmaterial ist.2. The method according to claim 1, characterized in that the magnetic material is a permanent magnet material.
3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß das Magnetmaterial Seltene Erden enthält.3. The method according to claim 1 or 2, characterized in that the magnetic material contains rare earths.
4. Verfahren nach mindestens einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß das gasförmige Material Wasserstoff ist.4. The method according to at least one of claims 1 to 3, characterized in that the gaseous material is hydrogen.
5. Verfahren nach mindestens einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß das gasförmige Material bei einer Temperatur im Bereich von 20°C bis 850 °C einwirkt.5. The method according to at least one of claims 1 to 4, characterized in that the gaseous material acts at a temperature in the range from 20 ° C to 850 ° C.
6. Verfahren nach mindestens einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß das gasförmige Material bei einem Druck im Bereich von 0,1 bar bis 150 bar einwirkt.6. The method according to at least one of claims 1 to 5, characterized in that the gaseous material acts at a pressure in the range of 0.1 bar to 150 bar.
7. Verfahren nach mindestens einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß das nach der Abtrennung des Magnetmaterials eine Entfernung des gasförmigen Materials mittels einer Temperaturbehandlung bei einer Temperatur im Bereich von 200 bis 850 °C erfolgt, wobei diese Temperaturbehandlung unter Vakuum oder einer Edelgas-Athmosphäre durchgeführt wird. 7. The method according to at least one of claims 1 to 6, characterized in that after the separation of the magnetic material, the gaseous material is removed by means of a temperature treatment at a temperature in the range from 200 to 850 ° C, this temperature treatment being carried out under vacuum or an inert gas atmosphere.
PCT/DE1999/003077 1998-09-24 1999-09-24 Method for reusing permanent magnets WO2000017894A1 (en)

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