EP0111616B1 - Use of additions to non-polluting foundry sands - Google Patents

Use of additions to non-polluting foundry sands Download PDF

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Publication number
EP0111616B1
EP0111616B1 EP83100419A EP83100419A EP0111616B1 EP 0111616 B1 EP0111616 B1 EP 0111616B1 EP 83100419 A EP83100419 A EP 83100419A EP 83100419 A EP83100419 A EP 83100419A EP 0111616 B1 EP0111616 B1 EP 0111616B1
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use according
carbon
carbon product
product
products
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EP0111616B2 (en
EP0111616A1 (en
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Ewald Schmidt
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Iko Industriekohle & Co KG Te Marl-Sinsen B GmbH
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SCHMIDT EWALD CARBOFORM CBF
Iko Industriekohle & Co KG GmbH
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives

Definitions

  • the present invention relates to the use of additives for foundry molding sand compositions which not only bring improved results in terms of foundry technology, but in particular meet the requirements from an environmental point of view in the workplace much better.
  • thermoplastic in unfoamed form as unsubstituted. polymerized hydrocarbon, e.g. B. consists of polymers of styrene, ethylene or propylene (see also DE-A-1 952 357).
  • Another proposal is to add resins to the foundry sand that are obtained as hydrocarbon polymers in the form of so-called petroleum resins during petroleum distillation (cf. DE-A-2 064 700).
  • the samples were kept at the respective temperature for 1 hour.
  • the effect of the carbon-containing additives used hitherto should be based on the volatilization of hydrocarbon compounds taking place under the conditions of the casting heat, after which the so-called glossy carbon separates above 650 ° C. after the formation of a reducing atmosphere.
  • the glossy carbon formed is intended to effect the separation between liquid metal and casting mold by encasing the grains of the casting mold sand.
  • the decomposition products and their composition of a gas coal and a hydrocarbon resin that occur during the thermal reaction in a reducing atmosphere are listed below.
  • the CHm i.e. the heavy hydrocarbons
  • the CHm is composed of:
  • the additives used according to the invention are carbon products which have a volatile content of 0.5 to 20%, preferably 0.5 to 10%, based on the Amount of carbon products freed of any mineral components present in the natural product.
  • the additives are advantageously present with a particle size of less than 1 mm, preferably less than 0.15 mm.
  • the so-called crystalline carbon products which generally contain less than 1% volatile constituents, are particularly suitable as such products. Since these products are generally relatively expensive products, organic carbon products can be mixed in, which can form crystalline carbons above 650 ° C in the reducing atmosphere formed during the casting process and have a volatile content of 1 to 20%. , preferably between 5 and 10%, provided that the total carbon product used according to the invention has volatile constituents only within the limits specified above and the maximum volatile constituent content of 20%, preferably 10%, is not exceeded.
  • naturally occurring graphite minerals generally contain considerable amounts of mineral constituents which must be separated from them before they can be used in known flotation or chemical treatment processes before they can be used as additives for foundry mold sands .
  • the product thus purified, which does not occur naturally in this pure form, is usually called. Inscribed "natural graphite”. (See tables 3 and 4 on page 6 ff.)
  • the thermal gas load during the casting process for the molding sands which contain the additives (carbon carriers) used according to the invention the amount of gas released is significantly lower.
  • the flames when pouring the hot liquid metal into the molds as is the case with the use of the known additives z. B. is based on gas coal and is done by igniting the released volatile constituents in the molding sand, no longer occurs when using molding sands with the carbon carriers used as additives according to the invention.
  • the amounts of carbon carriers added to regenerate the molding sand can be reduced by 25 to 50%, with the result that the environmental impact in the foundry is reduced to a minimum.
  • the combination of the crystalline carbon products with anthracite or lean coal as an admixed carbon product has proven to be particularly advantageous.
  • Anthracite and lean coal react during the casting process at low temperatures (150 to 400 ° C) with the atmospheric oxygen present in the mold cavity, and thus very quickly create a reducing atmosphere, which is a prerequisite for the fact that the crystalline carbon products now also have very low losses or suffer after the casting process.
  • the additives to foundry sand compositions used according to the invention form an ideal protective layer between the liquid metal and the molding sand composition, thus preventing reactions between the molten metal and the molding sand.
  • a further advantage when using the additives (carbon carriers) used according to the invention is the low water requirement of the molding sand according to the invention thus formed during the preparation process, since the additives (carbon carriers) used according to the invention have a substantially smaller surface area than the conventional carbon compounds.
  • the flow and compression behavior of the molding sand mixed with the additives used according to the invention is also improved, since the additives (carbon carriers) used according to the invention considerably reduce the frictional resistance of the quartz grains coated with clay.
  • the molding sand and the additives used according to the invention the environmental impact in the foundry is considerably reduced.
  • 70,000 t / year of carbon carriers additives to foundry sands on a carbon basis with a share of components that are volatile at casting temperatures of 38 to 40%, i.e. approx. 20,000 t / year of hydrocarbon compounds are used in the atmosphere submitted.
  • 20,000 t / year hydrocarbon compounds correspond, based on the volatile content of approx. 40%, to 10 612 000 m 3 gas, 85 400 kg tar and 272 000 kg benzene.
  • the sands were used as model sand without sieving.
  • Samples 1-5 show no leaf ribs, samples 6 and 7, on the other hand, have a strong tendency to leaf ribs, and samples 8 showed only weak roots.

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Abstract

1. The use of a carbon product or of several such products, containing volatile components to a total of 0.5-20% by weight, wherein with naturally occurring products containing mineral materials the content in volatile components is calculated to the natural product without the mineral components.

Description

Die vorliegende Erfindung betrifft die Verwendung von Zusätzen zu Gießereiformsandmassen, die nicht nur gießereitechnisch verbesserte Ergebnisse bringen, sondern insbesondere den Forderungen aus Umweltschutzsicht am Arbeitsplatz wesentlich besser nachkommen.The present invention relates to the use of additives for foundry molding sand compositions which not only bring improved results in terms of foundry technology, but in particular meet the requirements from an environmental point of view in the workplace much better.

Es ist bekannt, Formsanden, die zur Herstellung von Gußformen bestimmt sind, kohlenstoffhaltige Zusätze neben üblichen Bindemitteln, wie z. B. Bentonit, zuzugeben. Ein Beispiel hierfür ist Steinkohlestaub, der insbesondere zugesetzt wird, um die Oberflächengüte der erhaltenen Gußstücke zu verbessern (vgl. DE-A-1 952 357). Die Zugabe von Steinkohlenstaub erfolgt dabei in der Annahme, daß beim Gießen durch seine Gasbildung und die Umhüllung der Quarzkörner mit Kohle ein Anbrennen des Sandes am Gießstück vermieden und somit eine glatte und saubere Oberfläche erzeugt wird. Auch wurde gefunden, daß die Verwendung von Steinkohlenstaub im Formsand zum Ausgleich der Sandausdehnung und zur Vermeidung von Sandfehlern beiträgt. Ein anderer Vorschlag geht dahin, daß der Zusatz aus einem thermoplastischen Kunststoff in ungeschäumter Form als nichtsubstituierter. polymerisierter Kohlenwasserstoff, z. B. aus Polymeren des Styrols, Äthylens oder Propylens besteht (vgl. ebenso DE-A-1 952 357). Hierdurch wollte man die bisher verwendeten Kohlenstäube ersetzen und die beschriebenen thermoplastischen Kunststoffe einsetzen, insbesondere in der Annahme, daß hierdurch in Gießformen Glanzkohlenstoff unter dem Einfluß der Gießtemperatur gebildet wird, der die Körner des Formsandes mit einer Haut umgibt und die Quarzkörner der Formmasse umhüllt. Ein anderer Vorschlag geht dahin, dem Gießereisand Harze zuzusetzen, die als Kohlenwasserstoffpolymere in Form sogenannter Petrolharze bei der Erdöldestillation gewonnen werden (vgl. DE-A-2 064 700). Auch diese Lösung geht davon aus, daß unter den Bedingungen der Gießhitze eine teilweise Verflüchtigung der Zusätze stattfindet und anschließend Glanzkohlenstoff aus der Gasphase abgeschieden wird, der dann die Trennung zwischen Metall und Formstoff bewirkt. Jedoch sind die erreichten Ziele immer noch höchst unbefriedigend, insbesondere unter dem Gesichtspunkt des Umweltschutzes am Arbeitsplatz und im Allgemeinen. Die nachfolgende Tabelle 1 führt die bisher verwendeten Produkte auf und die nach standardisierten, international akzeptierten Meßmethoden, d. h. DIN 5172 gemessenen, bei der Gießhitze flüchtigen Bestandteile. Die nachfolgende Tabelle 2 gibt die aus verschiedenen Produkten zwischen 400 und 700 °C in oxidierender bzw. reduzierender Atmosphäre abgegebenen Gesamtmengen an flüchtigen Bestandteilen.
(Siehe Tabellen 1 und 2 Seite 3 ff.)

Figure imgb0001
Figure imgb0002
 It is known to use molding sands intended for the production of molds, carbon-containing additives in addition to conventional binders, such as, for. B. bentonite. An example of this is hard coal dust, which is added in particular to improve the surface quality of the castings obtained (cf. DE-A-1 952 357). The addition of hard coal dust takes place on the assumption that when casting due to its gas formation and the coating of the quartz grains with coal, burning of the sand on the casting is avoided and a smooth and clean surface is thus produced. It was also found that the use of hard coal dust in the molding sand helps to compensate for the expansion of the sand and to avoid sand defects. Another suggestion is that the addition of a thermoplastic in unfoamed form as unsubstituted. polymerized hydrocarbon, e.g. B. consists of polymers of styrene, ethylene or propylene (see also DE-A-1 952 357). This was intended to replace the coal dust used previously and to use the thermoplastic materials described, in particular on the assumption that glossy carbon is thereby formed in casting molds under the influence of the casting temperature, which surrounds the grains of the molding sand with a skin and envelops the quartz grains of the molding composition. Another proposal is to add resins to the foundry sand that are obtained as hydrocarbon polymers in the form of so-called petroleum resins during petroleum distillation (cf. DE-A-2 064 700). This solution also assumes that, under the conditions of the casting heat, some of the additives volatilize and then carbon is separated from the gas phase, which then causes the separation between metal and molding material. However, the goals achieved are still highly unsatisfactory, particularly in terms of environmental protection in the workplace and in general. Table 1 below lists the products used to date and the constituents which are volatile in the heat of pouring, measured using standardized, internationally accepted measurement methods, ie DIN 5172. Table 2 below shows the total amounts of volatile constituents released from various products between 400 and 700 ° C in an oxidizing or reducing atmosphere.
(See tables 1 and 2 page 3 ff.)
Figure imgb0001
Figure imgb0002

Die Proben wurden bei der jeweiligen Temperatur 1 h gehalten.The samples were kept at the respective temperature for 1 hour.

Nach allen bisherigen Verfahren soll die Wirkung der bisher verwendeten kohlenstoffhaltigen Zusätze auf der unter den Bedingungen der Gießhitze stattfindenden Verflüchtigung von Kohlenwasserstoffverbindungen beruhen, wonach sich nach Bildung einer reduzierenden Atmosphäre der sogenannte Glanzkohlenstoff oberhalb von 650 °C abscheidet. Der gebildete Glanzkohlenstoff soll die Trennung zwischen flüssigem Metall und Gießformmasse bewirken, indem er die Körner des Gießformsandes umhüllt.According to all previous processes, the effect of the carbon-containing additives used hitherto should be based on the volatilization of hydrocarbon compounds taking place under the conditions of the casting heat, after which the so-called glossy carbon separates above 650 ° C. after the formation of a reducing atmosphere. The glossy carbon formed is intended to effect the separation between liquid metal and casting mold by encasing the grains of the casting mold sand.

Nachfolgend werden die Zersetzungsprodukte und deren Zusammensetzung einer Gaskohle und eines Kohlenwasserstoffharzes aufgeführt, die während der thermischen Umsetzung in reduzierender Atmosphäre anfallen.The decomposition products and their composition of a gas coal and a hydrocarbon resin that occur during the thermal reaction in a reducing atmosphere are listed below.

A) Ausbringen an Gas, Benzol und Teer aus einer Gaskohle mit 33 % flüchtigen BestandteilenA) Application of gas, benzene and tar from a gas coal with 33% volatile components

Figure imgb0003
Figure imgb0003

Das CHm (d.h. die schweren Kohlenwasserstoffe) setzt sich zusammen aus :The CHm (i.e. the heavy hydrocarbons) is composed of:

Durchschnittliche Analyse des Gases.

Figure imgb0004
Average analysis of the gas.
Figure imgb0004

B) Analysenangaben der flüchtigen Bestandteile von Teer: im Siedebereich vonB) Analysis data for the volatile constituents of tar: in the boiling range of

  • 0-170 °C Benzol - Toluol - Xylol - Phenol - Pyridin0-170 ° C benzene - toluene - xylene - phenol - pyridine
  • 170-230 °C Naphthalin - Phenol - Kresol - Basen170-230 ° C naphthalene - phenol - cresol - bases
  • 230-270 °C Kreosot - Naphthalin - neutrale Öle230-270 ° C creosote - naphthalene - neutral oils
  • 270-350 °C Anthracen - Phenantren - Korbazol ca. 0,5 % Benzopyren-3,4270-350 ° C anthracene - phenantrene - korbazole approx. 0.5% benzopyrene-3.4
  • Pech : freier Kohlenstoff - Phenantren - Chrysen ca. 1,0 % Benzopyren-3,4Bad luck: free carbon - phenantrene - chrysene approx. 1.0% benzopyrene-3.4
  • Siedepunkt des Benzopyren-3,4 liegt bei 495,5 °CBoiling point of benzopyrene-3.4 is 495.5 ° C
  • Siedepunkt des Benzopyren-1,2 liegt bei 492,9 °CBoiling point of benzopyrene-1,2 is 492.9 ° C
C) Thermische Zersetzung eines Kohlenwasserstoffharzes bei 1 000 °C, Analyse der hierbei anfallenden flüchtigen BestandteileC) Thermal decomposition of a hydrocarbon resin at 1000 ° C, analysis of the volatile constituents

Figure imgb0005
Figure imgb0005
Figure imgb0006
Figure imgb0006

Wie ersichtlich werden bei Verwendung der vorbekannten Zusatzstoffe flüchtige Bestandteile abgegeben, die unter Umweltschutzgesichtspunkten äußerst schädliche Bestandteile enthalten, wie die heute als krebserzeugende Mittel in anderen technischen Bereichen z. B. als Lösungsmittel nicht mehr zugelassenen Aromaten Benzol, Toluol und Xylol. (Vgl. R.W. Schimberg et al., Belastung von Eisengießereiarbeitern durch mutagene polycyclische aromatische Kohlenwasserstoffe, Staub-Reinhalt. Luft Bd. 41 (1981) S. 421-424). Auch die beim Gießvorgang entstehenden Gase enthalten am Arbeitsplatz untragbar hohe Gehalte an Kohlenmonoxid.As can be seen, when using the known additives, volatile constituents are released which contain extremely harmful constituents from an environmental point of view, such as those which are used today as carcinogens in other technical areas, e.g. B. Aromatic benzene, toluene and xylene no longer approved as solvents. (See R.W. Schimberg et al., Exposure of iron foundry workers to mutagenic polycyclic aromatic hydrocarbons, cleanliness of dust. Luft Bd. 41 (1981) pp. 421-424). The gases generated during the casting process also contain unbearably high levels of carbon monoxide in the workplace.

Entgegen der bisherigen Annahme der Voraussetzung für die Wirksamkeit der bisher verwendeten kohlenstoffhaltigen Zusätze zu Gießereiformsanden stellen die erfindungsgemäß verwendeten Zusätze Kohlenstoffprodukte dar, die einen Gehalt an flüchtigen Bestandteilen von 0,5 bis 20 %, vorzugsweise 0,5 bis 10%, aufweisen bezogen auf die Menge des von gegebenenfalls im Naturprodukt anwesenden mineralischen Bestandteilen befreiten Kohlenstoffprodukte. Vorteilhaft liegen die Zusätze mit einer Teilchengröße von kleiner als 1 mm, vorzugsweise kleiner als 0,15 mm vor. Insbesondere sind als derartige Produkte die sogenannten kristallinen Kohlenstoffprodukte geeignet, die im allgemeinen unter 1 % flüchtige Bestandteile enthalten. Da es sich bei diesen Produkten im allgemeinen um relativ teure Produkte handelt, können organische Kohlenstoffprodukte zugemischt werden, die in der während des Gießvorganges gebildeten reduzierenden Atmosphäre oberhalb von 650 °C selbst kristalline Kohlenstoffe bilden können und einen Anteil an flüchtigen Bestandteilen von 1 bis 20 %, vorzugsweise zwischen 5 und 10 % aufweisen, vorausgesetzt, daß das erfindungsgemäß verwendete Gesamtkohlenstoffprodukt flüchtige Bestandteile nur innerhalb der vorstehend angegebenen Grenzen aufweisen und der maximale Gehalt an flüchtigen Bestandteilen von 20 %, vorzugsweise 10 %, nicht überschritten wird.Contrary to the previous assumption of the prerequisite for the effectiveness of the previously used carbon-containing additives for foundry molding sands, the additives used according to the invention are carbon products which have a volatile content of 0.5 to 20%, preferably 0.5 to 10%, based on the Amount of carbon products freed of any mineral components present in the natural product. The additives are advantageously present with a particle size of less than 1 mm, preferably less than 0.15 mm. The so-called crystalline carbon products, which generally contain less than 1% volatile constituents, are particularly suitable as such products. Since these products are generally relatively expensive products, organic carbon products can be mixed in, which can form crystalline carbons above 650 ° C in the reducing atmosphere formed during the casting process and have a volatile content of 1 to 20%. , preferably between 5 and 10%, provided that the total carbon product used according to the invention has volatile constituents only within the limits specified above and the maximum volatile constituent content of 20%, preferably 10%, is not exceeded.

Beispiele für erfindungsgemäß verwendbare kristalline Kohlenstoffprodukte und für zumischbare Kohlenstoffprodukte sind in Tabelle 3, bei den beim Vergießen von im Sand der Gießereiformen auftretenden Temperaturen abgegebenen flüchtigen Bestandteile in Tabelle 4 aufgeführt.Examples of crystalline carbon products which can be used according to the invention and of admixable carbon products are listed in Table 3, and the volatile constituents given off when casting temperatures in the sand of the foundry molds are listed in Table 4.

Der Ausdruck « Naturgraphit » ist hierbei so zu verstehen, daß die natürlich vorkommenden Graphitmineralien im allgemeinen beträchtliche Mengen an mineralischen Bestandteilen enthalten, welche vor ihrer Verwendbarkeit in bekannten Flotations- oder chemischen Behandlungsverfahren , hiervon getrennt werden müssen, bevor sie als Zusätze zu Gießereiformsande brauchbar sind. Das so gereinigte, nicht in dieser reinen Form in der Natur vorkommende Produkt wird üblicherweise als . « Naturgraphit » bezeichnet.
(Siehe Tabellen 3 und 4 Seite 6 ff.)

Figure imgb0007
Figure imgb0008
 The term "natural graphite" is to be understood here to mean that the naturally occurring graphite minerals generally contain considerable amounts of mineral constituents which must be separated from them before they can be used in known flotation or chemical treatment processes before they can be used as additives for foundry mold sands . The product thus purified, which does not occur naturally in this pure form, is usually called. Inscribed "natural graphite".
(See tables 3 and 4 on page 6 ff.)
Figure imgb0007
Figure imgb0008

Hieraus ist ersichtlich, daß bei der thermischen Belastung während des Gießprozesses bei den Formsanden, welche die erfindungsgemäß verwendeten Zusätzen (Kohlenstoffträgern) enthalten die abgegebene Gasmenge deutlich geringer ist. Allgemein ist zu beobachten, daß die Stichflammen beim Eingießen des heißen flüssigen Metalls in die Gießformen, wie es bei Verwendung der vorbekannten Zusätze z. B. auf Basis von Gaskohle üblich ist und durch Entzünden der freiwerdenden flüchtigen Bestandteile im Formsand geschieht, bei Verwendung von Formsanden mit den erfindungsgemäß als Zusätze verwendeten Kohlenstoffträgern nicht mehr auftritt. Die Zugabemengen an Kohlenstoffträgern zur Regenerierung des Formsandes können dazu um 25 bis 50 % reduziert werden, mit dem Ergebnis, daß die Umweltbelastung in der Gießerei auf ein Minimum herabgesetzt wird. Zahlreiche Gasuntersuchungen haben bestätigt, daß beim Einsatz von Kohlenstoffträgern mit einem Gehalt an flüchtigen Bestandteilen von 8 bis 10% waf, neben der Reduzierung der Kohlenwasserstoffverbindungen der Gehalt an Kohlenmonoxid in der Atmosphäre an der Gießstrecke und Auspackstation auf ca. 20 ppm herabgesetzt wird. Beim Einsatz von Kohlenstoffträgern mit einem Gehalt von flüchtigen Bestandteilen von 40 bis 45 % waf steigt der CO-Wert dort auf 80 bis 100 ppm, womit der MAK-Grenzwert von 50 ppm deutlich überschritten wird. Im Hinblick auf die bisherigen Lehren im Stand der Technik ist es überraschend, daß trotz der in den Zusätzen enthaltenen stark verringerten Mengen an flüchtigen Bestandteilen gerade die Oberfläche des Gießstücks frei von Fehlern ist, wie Bandrippen und dergl., die Trennung zwischen Formsand und Gießstück einwandfrei verläuft, und dies bei stark verringerter Menge an Zusatz zum Formsand.From this it can be seen that the thermal gas load during the casting process for the molding sands which contain the additives (carbon carriers) used according to the invention, the amount of gas released is significantly lower. In general, it can be observed that the flames when pouring the hot liquid metal into the molds, as is the case with the use of the known additives z. B. is based on gas coal and is done by igniting the released volatile constituents in the molding sand, no longer occurs when using molding sands with the carbon carriers used as additives according to the invention. The amounts of carbon carriers added to regenerate the molding sand can be reduced by 25 to 50%, with the result that the environmental impact in the foundry is reduced to a minimum. Numerous gas tests have confirmed that when using carbon carriers with a volatile content of 8 to 10%, in addition to reducing the hydrocarbon compounds, the carbon monoxide content in the atmosphere at the casting line and unpacking station is reduced to approximately 20 ppm. When using carbon carriers with a volatile content of 40 to 45% waf, the CO value increases to 80 to 100 ppm, which clearly exceeds the MAK limit of 50 ppm. In view of the previous teachings in the prior art, it is surprising that despite the greatly reduced amounts of volatile constituents contained in the additives, the surface of the casting is free from defects such as ribbon ribs and the like. The separation between molding sand and casting is flawless runs, and this with a greatly reduced amount of addition to the molding sand.

Die Kombination der kristallinen Kohlenstoffprodukte mit Anthrazit- bzw. Magerkohlen als Zumischkohlenstoffprodukt hat sich als besonders vorteilhaft erwiesen. Anthrazit- und Magerkohlen reagieren während des Gießprozesses bereits bei niedrigen Temperaturen (150 bis 400 °C) mit dem im Formhohlraum vorliegenden Luftsauerstoff, und schaffen somit sehr schnell eine reduzierende Atmosphäre, die Voraussetzung dafür ist, daß die kristallinen Kohlenstoffprodukte nun auch sehr geringe Verluste während oder nach dem Gießprozeß erleiden.The combination of the crystalline carbon products with anthracite or lean coal as an admixed carbon product has proven to be particularly advantageous. Anthracite and lean coal react during the casting process at low temperatures (150 to 400 ° C) with the atmospheric oxygen present in the mold cavity, and thus very quickly create a reducing atmosphere, which is a prerequisite for the fact that the crystalline carbon products now also have very low losses or suffer after the casting process.

Die erfindungsgemäß verwendeten Zusätze zu Gießereisandmassen bilden eine ideale Schutzschicht zwischen dem flüssigen Metall und der Formsandmasse, womit Reaktionen zwischen der Metallschmelze und dem Formsand verhindert werden.The additives to foundry sand compositions used according to the invention form an ideal protective layer between the liquid metal and the molding sand composition, thus preventing reactions between the molten metal and the molding sand.

Ein weiterer Vorteil bei Einsatz der erfindungsgemäß verwendeten Zusätze (Kohlenstoffträger) ist der geringe Wasserbedarf des so gebildeten erfindungsgemäßen Formsandes während des Aufbereitungsprozesses, da die erfindungsgemäß eingesetzten Zusätze (Kohlenstoffträger) gegenüber den herkömmlichen Kohlenstoffverbindungen eine wesentlich geringere Oberfläche aufweisen.A further advantage when using the additives (carbon carriers) used according to the invention is the low water requirement of the molding sand according to the invention thus formed during the preparation process, since the additives (carbon carriers) used according to the invention have a substantially smaller surface area than the conventional carbon compounds.

Das Fließ- und Verdichtungsverhalten des mit den erfindungsgemäß verwendeten Zusätzen versetzten Formsandes wird ebenfalls verbessert, da die erfindungsgemäß eingesetzten Zusätze (Kohlenstoffträger) den Reibungswiderstand der mit Ton umhüllten Quarzkörner erheblich herabsetzt.The flow and compression behavior of the molding sand mixed with the additives used according to the invention is also improved, since the additives (carbon carriers) used according to the invention considerably reduce the frictional resistance of the quartz grains coated with clay.

Neben den aufgeführten gießereitechnischen Vorteilen, des Formsandes und der erfindungsgemäß eingesetzten Zusätze wird die Umweltbelastung in der Gießerei erheblich verringert. Zur Zeit werden allein in der Bundesrepublik Deutschland ca. 70000 t/Jahr an Kohlenstoffträgern = Zusätzen zu Gießereisanden auf Kohlenstoffbasis mit einem Anteil an bei Vergießtemperaturen flüchtigen Bestandteilen um 38 bis 40 % eingesetzt, d. h. es werden ca. 20000 t/Jahr Kohlenwasserstoffverbindungen in die Atmosphäre abgegeben. 20 000 t/Jahr Kohlenwasserstöffverbindungen entsprechen, ausgehend vom Anteil an flüchtigen Bestandteilen von ca. 40 %,10 612 000 m3 Gas, 85 400 kg Teer und 272 000 kg Benzol.In addition to the listed technical foundry advantages, the molding sand and the additives used according to the invention, the environmental impact in the foundry is considerably reduced. In the Federal Republic of Germany alone, around 70,000 t / year of carbon carriers = additives to foundry sands on a carbon basis with a share of components that are volatile at casting temperatures of 38 to 40%, i.e. approx. 20,000 t / year of hydrocarbon compounds are used in the atmosphere submitted. 20,000 t / year hydrocarbon compounds correspond, based on the volatile content of approx. 40%, to 10 612 000 m 3 gas, 85 400 kg tar and 272 000 kg benzene.

VersuchsberichtTest report

Für die Versuche wurden folgende Sandmischungen hergestellt :

Figure imgb0009
The following sand mixtures were produced for the tests:
Figure imgb0009

Es wurden 8 Mischungen hergestellt:

  • Mischungen 1-5 : Kohlenstoffträger = Naturgraphit mit unterschiedlichen Oberflächen
  • Mischung 6 : Kohlenstoffträger = reines Bitumen
  • Mischung 7 : Kohlenstoffträger = Gemisch aus hochflüchtiger Kohle + Bitumen
  • Mischung 8 : Kohlenstoffträger = Gemisch aus niederflüchtiger Kohle + Bitumen
8 mixtures were made:
  • Mixtures 1-5: carbon carrier = natural graphite with different surfaces
  • Mixture 6: carbon carrier = pure bitumen
  • Mixture 7: carbon carrier = mixture of highly volatile coal + bitumen
  • Mixture 8: carbon carrier = mixture of low-volatile coal + bitumen

Die Sandmischungen weisen folgende Sandwerte auf :

  • Mischung H2 = Druckfestigkeit Verdichtbarkeit Prüfkörpergewicht
    (Siehe Tabelle Seite 9 f.)
    Figure imgb0010
The sand mixtures have the following sand values:
  • Mixture H 2 = compressive strength compressibility test specimen weight
    (See table on page 9 f.)
    Figure imgb0010

Für alle Versuche wurde ein spezielles Modell ausgesucht, damit Vergleiche möglich sind.A special model was selected for all tests so that comparisons are possible.

Die Sande wurden als Modellsand ohne Aufsiebung eingesetzt.The sands were used as model sand without sieving.

Beim Abgießen aller Kästen zeigte sich, daß bei den Proben 6, 7 und 8 eine stärkere Flammbildung auftrat.When all the boxes were poured off, it was found that samples 6, 7 and 8 showed greater flame formation.

GasanalyseGas analysis

Probennahme

  • 1 Gießstrecke vor dem Abgießen
  • 2 Gießstrecke während des Abgießens
  • 3 Auspackstation während des Auspackens
    Figure imgb0011
Sampling
  • 1 pouring line before pouring
  • 2 casting line during pouring
  • 3 Unpacking station during unpacking
    Figure imgb0011

AuspackverhaltenUnpacking behavior

Die Gußstücke bzw. Proben wurden unter gleichen Bedingungen ausgepackt. Die Proben 1-8 konnten wie folgt beurteilt werden :

  • Probe 1 praktisch keine Geruchsbildung
  • Probe 2 praktisch keine Geruchsbildung
  • Probe 3 praktisch keine Geruchsbildung
  • Probe 4 praktisch keine Geruchsbildung
  • Probe 5 praktisch keine Geruchsbildung
  • Probe 6 sehr starke Geruchsbildung
  • Probe 7 starke Geruchsbildung
  • Probe 8 starke Geruchsbildung
The castings or samples were unpacked under the same conditions. Samples 1-8 could be assessed as follows:
  • Sample 1 practically no odor
  • Sample 2 practically no odor
  • Sample 3 practically no odor
  • Sample 4 practically no odor
  • Sample 5 practically no odor
  • Sample 6 very strong odor
  • Sample 7 strong odor
  • Sample 8 strong odor

Gußstücke nach dem StrahlenCastings after blasting

Zunächst wurden die allgemeinen Gußoberflächen beurteilt.First the general cast surfaces were assessed.

Proben 1-8 saubere OberflächenSamples 1-8 clean surfaces

Das Gußstück neigt zur Blattrippenbildung und es konnte festgestellt werden, daß die Blattrippenbildung steigt, je höher die flüchtigen Bestandteile im Kohlenstoffträger sind.The casting tends to form leaf ribs and it has been found that the higher the volatile constituents in the carbon carrier, the more the leaf ribs form.

Die Proben 1-5 zeigen keine Blattrippen, dagegen Proben 6 und 7 starke Blattrippenneigung und bei der Probe 8 waren nur schwache Ansätze von Blattrippen zu verzeichnen.Samples 1-5 show no leaf ribs, samples 6 and 7, on the other hand, have a strong tendency to leaf ribs, and samples 8 showed only weak roots.

Claims (8)

1. The use of a carbon product or of several such products, containing volatile components to a total of 0.5-20 % by weight, wherein with naturally occurring products containing mineral materials the content in volatile components is calculated to the natural product without the mineral components.
2. The use according to claim 1 characterised in that the carbon product or products is fine-grain or coarse crystalline carbon product, lampblack, pyrographite, pyrocarbon product, anthrazite coal or non- coking coal.
3. The use according to claim 1 or 2, characterised in that the additive product is present in a particle size of less than 1 mm.
4. The use according to claim 2 or 3, characterised in that the carbon product is a crystalline carbon product.
5. The use according to claim 4, characterised in that the crystalline carbon product was prepared from hydrocarbon-containing compounds in a reducing atmosphere at a temperature between 650 and 1,000 °C.
6. The use according to claim 4, characterised in that the crystalline carbon product is a natural graphite.
7. The use according to claim 6, characterised in that the natural graphite has a surface of 0.4-15 m2.
8. The use according to claim 4, characterised in that the crystalline carbon product consists of synthetic graphites.
EP83100419A 1982-12-15 1983-01-18 Use of additions to non-polluting foundry sands Expired - Lifetime EP0111616B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83100419T ATE22021T1 (en) 1982-12-15 1983-01-18 USE OF ADDITIVES FOR ECO-FRIENDLY FOUNDRY MOLDING SANDS.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3246324A DE3246324C2 (en) 1982-12-15 1982-12-15 Use of carbon products as an additive to clay-bound foundry molding sand masses
DE3246324 1982-12-15

Publications (3)

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EP0111616A1 EP0111616A1 (en) 1984-06-27
EP0111616B1 true EP0111616B1 (en) 1986-09-10
EP0111616B2 EP0111616B2 (en) 1992-10-21

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EP (1) EP0111616B2 (en)
AT (1) ATE22021T1 (en)
DE (1) DE3246324C2 (en)
DK (1) DK162265C (en)
GR (1) GR79166B (en)
IE (1) IE54891B1 (en)

Cited By (1)

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Publication number Priority date Publication date Assignee Title
DE3704726A1 (en) * 1987-02-14 1988-08-25 Iko Gmbh & Co Kg METHOD FOR ACCELERATING THE WATER ADDITION OF BENTONITE, IN PARTICULAR AS AN ADDITIVE FOR MOLDED SAND

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3614397A1 (en) * 1986-04-28 1987-10-29 Wolfgang Caspers Process for reducing emissions, in particular emissions of hydrocarbon compounds, during the casting of metals
US5094289A (en) * 1990-09-19 1992-03-10 American Colloid Company Roasted carbon molding (foundry) sand and method of casting
US5215143A (en) * 1992-11-16 1993-06-01 American Colloid Company Non-porous carbon molding (foundry) sand and method of casting
PT1417059E (en) * 2001-08-14 2005-05-31 Climarotec Ges Raumklimatische METHOD AND CASE OF METAL FUNDING TO REDUCE THE EMISSION OF POLLUTANT SUBSTANCES IN FOUNDRY FACTORIES
DE10205158A1 (en) 2002-02-07 2003-08-21 Iko Minerals Gmbh Process for producing a molding sand, particularly in a cycle, for foundry purposes
DE102009041677A1 (en) 2009-09-16 2011-03-24 Süd-Chemie AG Foundry additive based on graphite

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DE1169087B (en) * 1957-11-05 1964-04-30 Sulzer Ag Use of additives to the casting molding compound to protect the edge zone of steel castings against edge decarburization
DE1952357A1 (en) * 1969-10-17 1971-04-29 Ravensberger Eisenhuette Styrene ethylene or propylene polymers - replacing carbon dust in casting mould comps
DE1925589A1 (en) * 1969-05-20 1970-11-26 Heinze & Co Dr Moulding material for the making of cores - and moulds used in the casting of metal
DE2064700A1 (en) * 1970-12-31 1972-07-27 Schuiling Metall Chemie N.V., Hengelo (Niederlande) Molding material set for foundry sands
CH555789A (en) * 1971-06-10 1974-11-15 Fischer Ag Georg PROCESS FOR MANUFACTURING MOLDED CARBON BODIES, IN PARTICULAR CASTING CHILLES.
DE2501872B1 (en) * 1975-01-15 1976-04-08 Mannesmann Ag Refractory ceramic compsn esp for casting moulds - contg carbon silicon, fused lime, opt binder and metal oxide
DE2638042A1 (en) * 1975-09-17 1977-03-24 Fischer Ag Georg PROCESS FOR TREATMENT OF POROESE, GRAY BASE MATERIALS, IN PARTICULAR FOR THE PRODUCTION OF FOUNDRY SANDS
JPS5817145B2 (en) * 1978-12-05 1983-04-05 品川白煉瓦株式会社 graphite refractories
IT1209745B (en) * 1980-01-21 1989-08-30 Ind Chimica Carlo Laviosa Spa GRANULAR MATERIAL FOR THE PREPARATION OF FOUNDRY FORMING LANDS AND ITS PRODUCTION PROCESS

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3704726A1 (en) * 1987-02-14 1988-08-25 Iko Gmbh & Co Kg METHOD FOR ACCELERATING THE WATER ADDITION OF BENTONITE, IN PARTICULAR AS AN ADDITIVE FOR MOLDED SAND
DE3704726C3 (en) * 1987-02-14 1998-01-08 Iko Gmbh & Co Kg Process for accelerating water adsorption of bentonite used as an additive for foundry mold sands

Also Published As

Publication number Publication date
DK575683A (en) 1984-06-16
IE832968L (en) 1984-06-22
GR79166B (en) 1984-10-02
EP0111616B2 (en) 1992-10-21
IE54891B1 (en) 1990-03-14
EP0111616A1 (en) 1984-06-27
DE3246324A1 (en) 1984-07-19
DK575683D0 (en) 1983-12-14
DK162265B (en) 1991-10-07
DK162265C (en) 1992-03-16
ATE22021T1 (en) 1986-09-15
DE3246324C3 (en) 1994-07-14
DE3246324C2 (en) 1994-07-14

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