EP0116272B1 - Manufacturing process of silicon and iron free blast material for surface treatment - Google Patents

Manufacturing process of silicon and iron free blast material for surface treatment Download PDF

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Publication number
EP0116272B1
EP0116272B1 EP84100095A EP84100095A EP0116272B1 EP 0116272 B1 EP0116272 B1 EP 0116272B1 EP 84100095 A EP84100095 A EP 84100095A EP 84100095 A EP84100095 A EP 84100095A EP 0116272 B1 EP0116272 B1 EP 0116272B1
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Prior art keywords
iron
raw material
magnetic separation
weight
maximum
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EP84100095A
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German (de)
French (fr)
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EP0116272A3 (en
EP0116272A2 (en
Inventor
Willy Dr.-Ing. Ulrich
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ASIKOS STRAHLMITTEL GMBH TE DINSLAKEN, BONDSREPUBL
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Krupp-Steag Strahlmittel GmbH
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B31/00—Machines or devices designed for polishing or abrading surfaces on work by means of tumbling apparatus or other apparatus in which the work and/or the abrasive material is loose; Accessories therefor
    • B24B31/12—Accessories; Protective equipment or safety devices; Installations for exhaustion of dust or for sound absorption specially adapted for machines covered by group B24B31/00
    • B24B31/14—Abrading-bodies specially designed for tumbling apparatus, e.g. abrading-balls
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C11/00—Selection of abrasive materials or additives for abrasive blasts

Definitions

  • the invention relates to a method according to the preamble of claim 1.
  • abrasives are used for the surface treatment, especially of austenitic steels, which are almost iron-free, such as aluminum oxide, zircon sand and glass beads.
  • the iron oxide content is limited to a maximum of 0.1% by weight.
  • the object of the invention is to enable the production of a further silicon-free and iron-free abrasive which is also particularly suitable for the surface treatment of austenitic steels and is not very expensive.
  • the melting chamber slag granulate obtained in hard coal furnaces is to be used as the starting material.
  • the melting chamber slag granules are comminuted to the desired grain size before the resulting raw material with a total iron content of at most about 7% by weight, in the present mainly in the form of iron silicate and iron aluminate, is essentially freed from the iron present in metallic form by magnetic separation becomes.
  • Magnetic separation in which a thin raw material layer is preferably passed over magnetic drums, can be carried out in one or more stages depending on the layer thickness and the grain size distribution present; in many cases, a single-stage magnetic separation is sufficient to achieve or fall below the required metallic iron content of at most 0.1% by weight.
  • the surprising result achieved with the proposed method is that the above-mentioned maximum proportion of metallic iron can be maintained with the specified, less complex measures, although the total iron content of the raw material present after comminution is several times the factor 10 greater than the maximum proportion to be observed.
  • the surface effect achieved by means of the blasting agent can be adjusted by changing the grain size distribution of the blasting agent; a lower roughness depth can be achieved in particular by reducing the maximum permissible grain size.
  • the process can in particular be carried out in such a way that the desired grain fractions are sieved off only after magnetic separation; However, it is also possible to screen the raw material before carrying out the magnetic separation and to separate the resulting grain fractions from one another using suitable magnetic separators. Grain screening can take place, in particular, in the fractions that comply with the regulation according to DIN 8201 for aluminum oxide.
  • the method can in particular also be carried out in such a way that the melt chamber slag granules are comminuted into a raw material with a grain size of at most 0.25 mm before magnetic separation (claim 2); the melting chamber slag granulate is preferably comminuted as a raw material to a grain size which is predominantly in the range between 0.06 and 0.25 mm (claim 3).
  • An expedient development of the method according to the invention consists in that the layer of raw material subjected to magnetic separation has a thickness of at most five times, preferably two to three times, the maximum grain size (claim 5).
  • the layer in question should be set as thin as possible in order to be able to carry out the deposition of metallic iron as effectively as possible and, if possible, already in a single deposition stage.
  • the layer thickness can be adjusted in particular by suitable coordination between the amount of comminuted raw material fed in and the speed of the magnetic separator (s).
  • the abrasive produced from hard coal furnaces according to the teaching of the invention using melting chamber slag granules has the following typical chemical composition; the individual components are each given in% by weight:
  • the particle size distribution of the abrasive is as follows:
  • the abrasive therefore consists of approximately 70% grains in the range between 0.5 mm and 0.1 mm.
  • an abrasive of the listed composition has a significantly larger total iron content than, for example, zircon sand used for comparison (total iron content only about 0.2% by weight), its use for blasting stainless steels on these does not lead to extraneous rust formation if the melt chamber slag granulate serving as the starting material , which has been converted into a sufficiently comminuted raw material, the metallic iron is essentially removed beforehand by magnetic separation.
  • the manufacturing method according to the invention described at the outset can in particular be further developed in that the raw material is additionally subjected to a drying process at a suitable point in time, in particular also simultaneously with or after the magnetic deposition.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Glass Compositions (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

1. Manufacturing process for a silicosis and iron-free blast material for surface treatment, in particular of Austenitic steels, with a maximum grain size of 0.5 mm, made of crushed smelter slag granulate from hard coal combustion, characterized by crushing of the smelter slag granulate to the desired size before the raw material (with a maximum total iron content of approximately 7 % by weight, primarily occuring as iron silicate and iron aluminate) undergoes magnetic separation, resulting in a maximum metallic iron content of 0.1 % by weight.

Description

Die Erfindung betrifft ein Verfahren gemäß Oberbegriff von Patentanspruch 1.The invention relates to a method according to the preamble of claim 1.

Zur Zeit werden für die Oberflächenbehandlung insbesondere von austenitischen Stählen ausschließlich Strahlmittel eingesetzt, die wie Elektrokorund, Zirkonsand und Glasperlen nahezu eisenfrei sind. Der Eisenoxidanteil ist dabei begrenzt auf höchstens 0,1 Gew.-%.At the moment, only abrasives are used for the surface treatment, especially of austenitic steels, which are almost iron-free, such as aluminum oxide, zircon sand and glass beads. The iron oxide content is limited to a maximum of 0.1% by weight.

Aus «Stahl und Eisen" 75 (1955), Seiten 1115 bis 1117, ist es bereits bekannt, Strahlmittel aus feuerfester Schlacke zu bestimmten Zwecken auf eine Korngröße auch unterhalb von 0,5 mm zu zermahlen. Durch den Zerkleinerungsvorgang wird dabei bereits der Endzustand des Strahlmittels hinsichtlich Zusammensetzung und Eigenschaften herbeigeführt.From "Stahl und Eisen" 75 (1955), pages 1115 to 1117, it is already known to grind fireproof slag abrasives for certain purposes to a grain size below 0.5 mm. The crushing process already results in the final state of the Abrasive brought about in terms of composition and properties.

Der Erfindung liegt die Aufgabe zugrunde, die Herstellung eines weiteren silikose- und eisenfreien Strahlmittels zu ermöglichen, welches ebenfalls insbesondere zur Oberflächenbehandlung von austenitischen Stählen geeignet und wenig kostenaufwendig ist. Als Ausgangsmaterial soll das in Steinkohlenfeuerungen anfallende Schmelzkammerschlackengranulat Verwendung finden.The object of the invention is to enable the production of a further silicon-free and iron-free abrasive which is also particularly suitable for the surface treatment of austenitic steels and is not very expensive. The melting chamber slag granulate obtained in hard coal furnaces is to be used as the starting material.

Die gestellte Aufgabe wird durch ein Verfahren gelöst, welches die Merkmale des Patentanspruchs 1 aufweist. Danach findet die Zerkleinerung des Schmelzkammerschlackengranulats auf die gewünschte Korngröße statt, bevor das dabei entstandene Rohmaterial mit einem Gesamteisengehalt von höchstens etwa 7 Gew.-%, vorliegend überwiegend in Form von Eisensilikat und Eisenaluminat, durch Magnetabscheidung im wesentlichen von dem in metallischer Form vorliegenden Eisen befreit wird.The stated object is achieved by a method which has the features of patent claim 1. Thereafter, the melting chamber slag granules are comminuted to the desired grain size before the resulting raw material with a total iron content of at most about 7% by weight, in the present mainly in the form of iron silicate and iron aluminate, is essentially freed from the iron present in metallic form by magnetic separation becomes.

Die Magnetabscheidung, bei welcher eine dünne Rohmaterialschicht vorzugsweise über Magnettrommeln geführt wird, kann je nach der Schichtdicke und der vorliegenden Korngrößenverteilung ein- oder mehrstufig durchgeführt werden; in vielen Fällen ist bereits eine einstufige Magnetabscheidung ausreichend, um den erforderlichen Gehalt an metallischem Eisen von höchstens 0,1 Gew.-% zu erreichen oder zu unterschreiten. Das mit dem vorgeschlagenen Verfahren erzielte überraschende Ergebnis besteht darin, daß sich mit den angegebenen, wenig aufwendigen Maßnahmen der erwähnte Höchstanteil an metallischem Eisen einhalten läßt, obwohl der Gesamteisengehalt des nach Zerkleinerung vorliegenden Rohmaterials um das Mehrfache des Faktors 10 größer ist als der einzuhaltende Höchstanteil.Magnetic separation, in which a thin raw material layer is preferably passed over magnetic drums, can be carried out in one or more stages depending on the layer thickness and the grain size distribution present; in many cases, a single-stage magnetic separation is sufficient to achieve or fall below the required metallic iron content of at most 0.1% by weight. The surprising result achieved with the proposed method is that the above-mentioned maximum proportion of metallic iron can be maintained with the specified, less complex measures, although the total iron content of the raw material present after comminution is several times the factor 10 greater than the maximum proportion to be observed.

Darüber hinaus haben Korrosionsversuche mit bestrahlten austenitischen Stählen erkennen lassen, daß die Behandlung mit dem auf diese Weise hergestellten eisenfreien Strahlmittel nicht zu einer Fremdrostbildung führt. Das nach der Lehre der Erfindung hergestellte Strahlmittel ist also geeignet, die eingangs erwähnten bekannten Strahlmittel zu ersetzen.In addition, corrosion tests with irradiated austenitic steels have shown that treatment with the iron-free abrasive produced in this way does not lead to the formation of extraneous rust. The blasting medium produced according to the teaching of the invention is therefore suitable for replacing the known blasting medium mentioned at the outset.

Die mittels des Strahlmittels erzielte Oberflächenwirkung (Rauhtiefe der bestrahlten Oberfläche) kann dadurch angepaßt werden, daß die Korngrößenverteilung des Strahlmittels verändert wird; eine geringere Rauhtiefe kann insbesondere dadurch erzielt werden, daß die maximal zulässige Korngröße herabgesetzt wird.The surface effect achieved by means of the blasting agent (surface roughness of the irradiated surface) can be adjusted by changing the grain size distribution of the blasting agent; a lower roughness depth can be achieved in particular by reducing the maximum permissible grain size.

Das Verfahren kann insbesondere in der Weise durchgeführt werden, daß die gewünschten Kornfraktionen erst nach der Magnetabscheidung abgesiebt werden; es ist jedoch auch möglich, das Rohmaterial vor der Durchführung der Magnetabscheidung abzusieben und die dabei entstandenen Kornfraktionen getrennt voneinander über geeignete Magnetabscheider zu führen. Die Kornabsiebung kann insbesondere in den Fraktionen erfolgen, die der Vorschrift gemäß DIN 8201 für Elektrokorund entsprechen.The process can in particular be carried out in such a way that the desired grain fractions are sieved off only after magnetic separation; However, it is also possible to screen the raw material before carrying out the magnetic separation and to separate the resulting grain fractions from one another using suitable magnetic separators. Grain screening can take place, in particular, in the fractions that comply with the regulation according to DIN 8201 for aluminum oxide.

Das Verfahren läßt sich insbesondere auch in der Weise ausführen, daß das Schmelzkammerschlackengranulat vor der Magnetabscheidung in ein Rohmaterial mit einer Korngröße von höchstens 0,25 mm zerkleinert wird (Patentanspruch 2); vorzugsweise wird das Schmelzkammerschlackengranulat als Rohmaterial auf eine Korngröße zerkleinert, die überwiegend im Bereich zwischen 0,06 bis 0,25 mm liegt (Patentanspruch 3).The method can in particular also be carried out in such a way that the melt chamber slag granules are comminuted into a raw material with a grain size of at most 0.25 mm before magnetic separation (claim 2); the melting chamber slag granulate is preferably comminuted as a raw material to a grain size which is predominantly in the range between 0.06 and 0.25 mm (claim 3).

Besonders vorteilhaft ist die Verwendung von Rohmaterial, dessen Gesamteisengehalt vor der Magnetabscheidung nicht höher liegt als etwa 6, vorzugsweise 5,5 Gew.-% (Patentanspruch 4).It is particularly advantageous to use raw material, the total iron content of which before the magnetic separation is no higher than about 6, preferably 5.5% by weight (claim 4).

Eine zweckmäßige Weiterbildung des erfindungsgemäßen Verfahrens besteht darin, daß die der Magnetabscheidung unterworfene Schicht Rohmaterial eine Dicke allenfalls in der Größenordnung der fünffachen, vorzugsweise der zweibis dreifachen, maximalen Korngröße aufweist (Patentanspruch 5).An expedient development of the method according to the invention consists in that the layer of raw material subjected to magnetic separation has a thickness of at most five times, preferably two to three times, the maximum grain size (claim 5).

Allgemein gesprochen sollte die in Rede stehende Schicht möglichst dünn eingestellt werden, um die Abscheidung metallischen Eisens möglichst wirksam und möglichst bereits in einer einzigen Abscheidungsstufe vornehmen zu können. Die Schichtdicke kann insbesondere durch geeignete Abstimmung zwischen der Zuführmenge an zerkleinertem Rohmaterial und der Geschwindigkeit des bzw. der Magnetabscheider eingestellt werden.Generally speaking, the layer in question should be set as thin as possible in order to be able to carry out the deposition of metallic iron as effectively as possible and, if possible, already in a single deposition stage. The layer thickness can be adjusted in particular by suitable coordination between the amount of comminuted raw material fed in and the speed of the magnetic separator (s).

Das nach der Lehre der Erfindung unter Verwendung von Schmelzkammerschlackengranulat aus Steinkohlenfeuerungen hergestellte Strahlmittel weist die folgende typische chemische Zusammensetzung auf; die einzelnen Bestandteile sind dabei jeweils in Gew.-% angegeben:

Figure imgb0001
Figure imgb0002
 The abrasive produced from hard coal furnaces according to the teaching of the invention using melting chamber slag granules has the following typical chemical composition; the individual components are each given in% by weight:
Figure imgb0001
Figure imgb0002

Die Korngrößenverteilung des Strahlmittels ist die folgende:

Figure imgb0003
The particle size distribution of the abrasive is as follows:
Figure imgb0003

Das Strahlmittel besteht also zu etwa 70% aus Körnungen im Bereich zwischen 0,5 mm und 0,1 mm.The abrasive therefore consists of approximately 70% grains in the range between 0.5 mm and 0.1 mm.

Obwohl ein Strahlmittel der aufgeführten Zusammensetzung einen erheblich größeren Gesamteisenanteil aufweist als beispielsweise zum Vergleich benutzter Zirkonsand (Gesamteisenanteil nur etwa 0,2 Gew.-%), führt seine Verwendung zum Strahlen von nichtrostenden Stählen an diesen nicht zur Fremdrostbildung, wenn dem als Ausgangsmaterial dienenden Schmelzkammerschlackengranulat, welches in ein ausreichend zerkleinertes Rohmaterial umgewandelt worden ist, vorher durch Magnetabscheidung das metallische Eisen im wesentlichen entzogen wird.Although an abrasive of the listed composition has a significantly larger total iron content than, for example, zircon sand used for comparison (total iron content only about 0.2% by weight), its use for blasting stainless steels on these does not lead to extraneous rust formation if the melt chamber slag granulate serving as the starting material , which has been converted into a sufficiently comminuted raw material, the metallic iron is essentially removed beforehand by magnetic separation.

Das eingangs geschilderte erfindungsgemäße Herstellverfahren kann insbesondere dadurch weiter ausgestaltet sein, daß das Rohmaterial zu einem geeigneten Zeitpunkt, insbesondere auch gleichzeitig mit oder nach der Magnetabscheidung, zusätzlich einem Trocknungsvorgang unterworfen wird.The manufacturing method according to the invention described at the outset can in particular be further developed in that the raw material is additionally subjected to a drying process at a suitable point in time, in particular also simultaneously with or after the magnetic deposition.

Das unter Verwendung des Schmelzkammerschlackengranulats hergestellte Strahlmittel ist auch silikosefrei, da es einen Si02- bzw. Quarzgehalt von etwa 0,4 bis 0,5% aufweist. Zulässig ist ein Gehalt an freier, kristalliner Kieselsäure = Quarz bis zu 2%.The blasting agent produced using the melt chamber slag granulate is also free of silicosis, since it has an SiO 2 or quartz content of approximately 0.4 to 0.5%. A content of free, crystalline silica = quartz is allowed up to 2%.

Claims (5)

1. Manufacturing process for a silicosis and iron-free blast material for surface treatment, in particular of Austenitic steels, with a maximum grain size of 0.5 mm, made of crushed smelter slag granulate from hard coal combustion, characterized by crushing of the smelter slag granulate to the desired size before the raw material (with a maximum total iron content of approximately 7% by weight, primarily occuring as iron silicate and iron aluminate) undergoes magnetic separation, resulting in a maximum metallic iron content of 0.1 % by weight.
2. Process according to claim 1, characterized by the smelter slag granulate being crushed before magnetic separation into a raw material with a maximum grain size of 0.25 mm.
3. Process according to either of the claims 1 or 2, characterized by the smelter slag granulate as the raw material being crushed before magnetic separation into grains with a size primarily ranging between 0.06 and 0.25 mm.
4. Process according to one of the claims 1 to 3, characterized by the total iron content of the raw material prior to magnetic separation being not more than approximately 6%, preferably 5.5% by weight.
5. Process according to one of the claims 1 to 4, characterized by the layer of raw material subjected to magnetic separation being at most in the order of five times (preferably two to three times) thicker than the maximum grain size.
EP84100095A 1983-01-15 1984-01-07 Manufacturing process of silicon and iron free blast material for surface treatment Expired EP0116272B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84100095T ATE42055T1 (en) 1983-01-15 1984-01-07 PROCESS FOR THE MANUFACTURE OF A SILICOSE-FREE AND IRON-FREE ABRASIVE FOR SURFACE TREATMENT.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3301172 1983-01-15
DE3301172A DE3301172C1 (en) 1983-01-15 1983-01-15 Process for the production of a silicon and iron-free abrasive for surface treatment

Publications (3)

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EP0116272A2 EP0116272A2 (en) 1984-08-22
EP0116272A3 EP0116272A3 (en) 1986-08-20
EP0116272B1 true EP0116272B1 (en) 1989-04-12

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4343371C1 (en) * 1993-12-18 1994-09-29 Mineralienwerke Kuppenheim Gmb Process for dry cleaning of façades
JP4049848B2 (en) * 1997-07-29 2008-02-20 Ｊｆｅマテリアル株式会社 Abrasive
IT201800005627A1 (en) * 2018-05-23 2019-11-23 PROCEDURE FOR OBTAINING ABRASIVE MATERIALS FROM INERT AGGREGATES ARISING FROM METALLURGIC WASTE
US12091605B2 (en) * 2021-04-14 2024-09-17 Harsco Technologies LLC Demetallized slag for abrasives and/or roofing granules and related methods

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL297592A (en) * 1900-01-01
NL9082C (en) * 1900-01-01
GB1136396A (en) * 1965-07-23 1968-12-11 Fisons Ltd Treating steel making slag
JPS54146096A (en) * 1978-05-08 1979-11-14 Sumitomo Metal Ind Ltd Sand material for sand blast use

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EP0116272A3 (en) 1986-08-20
EP0116272A2 (en) 1984-08-22
DE3301172C1 (en) 1984-08-16
ATE42055T1 (en) 1989-04-15

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