EP0930113A1 - Powder for protecting centrifugal moulds for cast iron pipes and process for producing said powder - Google Patents

Powder for protecting centrifugal moulds for cast iron pipes and process for producing said powder Download PDF

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Publication number
EP0930113A1
EP0930113A1 EP99420004A EP99420004A EP0930113A1 EP 0930113 A1 EP0930113 A1 EP 0930113A1 EP 99420004 A EP99420004 A EP 99420004A EP 99420004 A EP99420004 A EP 99420004A EP 0930113 A1 EP0930113 A1 EP 0930113A1
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Prior art keywords
powder
silicon
cast iron
product according
mineral
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EP99420004A
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German (de)
French (fr)
Inventor
Thomas Margaria
Rolnad Siclari
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Ferropem SAS
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Pechiney Electrometallurgie SAS
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Publication of EP0930113A1 publication Critical patent/EP0930113A1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal
    • B22D11/111—Treating the molten metal by using protecting powders
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D13/00—Centrifugal casting; Casting by using centrifugal force
    • B22D13/10—Accessories for centrifugal casting apparatus, e.g. moulds, linings therefor, means for feeding molten metal, cleansing moulds, removing castings
    • B22D13/101—Moulds
    • B22D13/102—Linings for moulds

Definitions

  • the invention relates to a powder product intended for the protection of molds (often referred to as "shells") for centrifugal casting cast iron pipes.
  • Products used for the protection (also called poteyage) of shells of centrifugal casting of cast iron pipes are in powder form containing an inoculating alloy intended for the treatment of the external surface of the pipe.
  • This alloy is most often based on ferro-silicon, possibly alloyed with calcium, aluminum and / or strontium and sometimes other elements such as manganese or zirconium.
  • Silicon and calcium can also be provided under form of a silicon-calcium alloy. They also contain mineral powders inert such as carbon, silica, fluorspar or other fluorinated compounds, including the role is to facilitate the detachment of the pipe at the end of casting.
  • the industrial synthesis of silicones is carried out from alkyl- or aryl-halosilanes, in particular dimethyldichlorosilane, obtained by reaction of a contact mass based on powdered metallurgical silicon with methyl chloride, at a temperature between 300 and 350 ° C, in the presence of a catalyst containing copper and optionally tin.
  • This reaction known under the name of Rochow reaction, is used worldwide and leaves significant quantities of residues, called spent contact masses, appearing in the form of sludges containing various metallic elements in the form of silicides, silicates or oxides.
  • spent masses which ceased to be reactive under the conditions of the Rochow reaction, remain reactive in air and their landfilling requires prior passivation treatment.
  • Elkem's patent application EP 0786532 describes the manufacture of briquettes made of residues based on silicon mixed with cardboard, hydraulic cement and a ferro-alloy, and usable as metallurgical additive.
  • Application EP 0794160 from the applicant describes the recycling of spent masses in the form of a refractory powder based on silicon nitride which, mixed with an organic binder, makes it possible to produce plugs for tap holes for blast furnaces or electric metallurgy ovens.
  • silicone production due to the significant development of silicone production, it remains necessary to find other possibilities for recycling used materials.
  • the waste masses recovered at the outlet of the reactor are first treated, for example by means of a sulfuric acid solution containing from 15 to 50% by weight of pure acid, at a temperature between 20 and 100 ° C. Tin and copper are eliminated in the form of sulfates which can be reused.
  • the insoluble fraction that is to say the purified mass, is then dried and then takes the form of a powder with a particle size of less than 0.1 mm.
  • the content of non-oxidized silicon is very variable and this variability is a major obstacle to its recycling in industrial applications requiring a minimum of reproducibility.
  • the quality obtained should be checked at each stage of the process, which requires both an evaluation test of the inoculating power of the base material and a specific application test for the protection of centrifugal casting shells.
  • a melting crucible is treated in an induction furnace by adding 1 % by weight of base material, then poured into a sand mold to obtain test pieces of different thicknesses.
  • the quenching thickness that is to say the thickness of the skin of pearlitic structure around the core of the piece of ferritic structure, is checked on these test pieces, by optical microscopy.
  • liquid cast iron is poured into a fixed cylindrical mold with a vertical axis of porous sintered metal, the outer part of which is surrounded by an envelope waterproof allowing the vacuum to be drawn on the outside of the mold.
  • This device makes it possible to maintain the protective powder of product to be tested on the internal surface of the mold, and thus to prevent this powder from being swept away by the flow of liquid cast iron at the time of casting.
  • a cylindrical core of agglomerated sand placed in a coaxial position makes it possible to obtain the toric shape simulating that of a pipe.
  • the internal face of the mold is produced at an angle of 2 degrees to facilitate demolding.
  • the quality of the products tested is assessed in relation to the release time of the part under the sole action of gravity, and the depth of quenching observed on the outer skin of the part.
  • the test is carried out with a constant dosage of product to be tested of 200 g / m 2 .
  • the liquid cast iron required for the test is treated beforehand at 1550 ° C. by adding 14 g / kg of nickel-magnesium alloy cast iron to 15% magnesium.
  • the inoculating power of this alloy is tested by treating with 30 g of alloy 3 kg of Sorel cast iron melted at 1400 ° C in an induction furnace, and by casting this cast iron within 5 minutes following its treatment in a sand mold for obtain 20, 10, 5 and 2 mm thick test pieces.
  • test pieces is entirely perlitic for the two thinner ones, the perlite thickness being 3 mm on the 20 mm thick test piece and 4 mm on the 10 mm thick test piece.
  • a mixture consisting of 90% by weight of the preceding inoculating alloy and 10% of silica powder with a particle size between 50 and 100 ⁇ m is then prepared. This mixture is tested for shell protection in a vertical cylindrical mold with a diameter of 90 mm and a height of 130 mm, with a central graphite core with a diameter of 70 mm. The part obtained is released by gravity 20 s after the end of the casting and the thickness of perlite on the external surface is 2 mm.
  • Residues from the manufacture of dichloromethylsilane were collected at the outlet of a synthesis reactor and are treated with a sulfuric acid solution to remove the tin and copper.
  • the mixture is tested as an inoculant under the same conditions as in Example 1.
  • test pieces is completely perlitic for the thicknesses 2 and 5 mm, and that the thickness of perlite is respectively 3 and 2 mm for thicknesses of 10 and 20 mm.
  • the mixture without the addition of any other product, is then tested as a product for protecting the pipe casting shells under conditions identical to those of Example 1.
  • the casting is released from the mold 18 s after the end of the casting and the thickness of perlite on the external face is evaluated at 1.5 mm. It is therefore found that this product provides slightly better protection than that of Example 1.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mold Materials And Core Materials (AREA)
  • Silicon Compounds (AREA)

Abstract

The use of a silicon alloy, obtained from the residues of a Rochow reaction, mixed with an inert material such as silica or fluorinated silica, for the protection of the shells of centrifuged flow moulds for cast iron tubes. The powder protective material comprises a mixture of mineral powder and an innoculating agent based on silicon.At least part of the silicon is provided by used residues from the synthesis of silicones from alkyl- or aryl-halogenosilanes. An Independent claim is also included for the preparation of these materials.

Description

Domaine de l'inventionField of the invention

L'invention concerne un produit sous forme de poudre destiné à la protection des moules (désignés souvent sous le nom de "coquilles") de coulée par centrifugation des tuyaux de fonte.The invention relates to a powder product intended for the protection of molds (often referred to as "shells") for centrifugal casting cast iron pipes.

Etat de la techniqueState of the art

Les produits utilisés pour la protection (on parle également de poteyage) des coquilles de coulée par centrifugation des tuyaux de fonte se présentent sous forme de poudre contenant un alliage inoculant destiné au traitement de la surface externe du tuyau. Cet alliage est le plus souvent à base de ferro-silicium, éventuellement allié à du calcium, de l'aluminium et/ou du strontium et parfois d'autres éléments tels que le manganèse ou le zirconium. Le silicium et le calcium peuvent aussi être apportés sous forme d'un alliage silicium-calcium. Ils contiennent également des poudres minérales inertes comme le carbone, la silice, le spath-fluor ou d'autres composés fluorés, dont le rôle est de faciliter le décollement du tuyau en fin de coulée. Ainsi, le brevet US 4058153 (Pont-à-Mousson) décrit l'utilisation, pour la coulée centrifuge de tuyaux de fonte, d'un poteyage constitué d'un mélange de silice et de bentonite, et d'une mince couche d'inoculant, par exemple du ferrosilicium.Products used for the protection (also called poteyage) of shells of centrifugal casting of cast iron pipes are in powder form containing an inoculating alloy intended for the treatment of the external surface of the pipe. This alloy is most often based on ferro-silicon, possibly alloyed with calcium, aluminum and / or strontium and sometimes other elements such as manganese or zirconium. Silicon and calcium can also be provided under form of a silicon-calcium alloy. They also contain mineral powders inert such as carbon, silica, fluorspar or other fluorinated compounds, including the role is to facilitate the detachment of the pipe at the end of casting. So the US patent 4058153 (Pont-à-Mousson) describes the use, for the centrifugal casting of cast iron, a coating made of a mixture of silica and bentonite, and a thin inoculant layer, for example ferrosilicon.

La synthèse industrielle des silicones est effectuée à partir d'alkyl- ou aryl-halogénosilanes, notamment de diméthyldichlorosilane, obtenu par réaction d'une masse de contact à base de silicium métallurgique en poudre avec du chlorure de méthyle, à une température comprise entre 300 et 350°C, en présence d'un catalyseur contenant du cuivre et éventuellement de l'étain. Cette réaction, connue sous le nom de réaction de Rochow, est mondialement utilisée et laisse des quantités importantes de résidus, appelés masses de contact usées, se présentant sous la forme de boues contenant divers éléments métalliques sous formes de siliciures, de silicates ou d'oxydes.
Ces masses usées, qui ont cessé d'être réactives dans les conditions de la réaction de Rochow, restent réactives à l'air et leur mise en décharge nécessite un traitement préalable de passivation. Les procédés sont nombreux et consistent généralement à oxyder le produit soit à l'air, soit en milieu aqueux. Ainsi, les brevets US 4892694 et US 5126203 de General Electric proposent de stabiliser les masses usées sous forme de pellets imprégnés d'un liant organique tel que la lignine. Le brevet US 5274158 de la même société propose de traiter les résidus par chauffage entre 900 et 1500°C sous atmosphère inerte et EP 0601796 de chauffer entre 400 et 800°C en atmosphère d'oxygène.
D'autres procédés ont été proposés pour essayer de recycler les masses usées en produits réutilisables en évitant leur mise en décharge. Ainsi, WO 95/27086 d'Elkem décrit le traitement des masses usées au four électrique à arc pour récupérer le silicium et le cuivre. La demande de brevet EP 0786532 d'Elkem décrit la fabrication de briquettes constituées de résidus à base de silicium mélangés à du carton, du ciment hydraulique et un ferro-alliage, et utilisables comme additif métallurgique. La demande EP 0794160 de la demanderesse décrit le recyclage des masses usées sous forme d'une poudre réfractaire à base de nitrure de silicium qui, mélangée à un liant organique, permet de réaliser des bouchons de trous de coulée pour les hauts-fourneaux ou les fours électriques de métallurgie. Il reste cependant nécessaire, à cause du développement important de la production de silicones, de trouver d'autres possibilités de recyclage des masses usées.The industrial synthesis of silicones is carried out from alkyl- or aryl-halosilanes, in particular dimethyldichlorosilane, obtained by reaction of a contact mass based on powdered metallurgical silicon with methyl chloride, at a temperature between 300 and 350 ° C, in the presence of a catalyst containing copper and optionally tin. This reaction, known under the name of Rochow reaction, is used worldwide and leaves significant quantities of residues, called spent contact masses, appearing in the form of sludges containing various metallic elements in the form of silicides, silicates or oxides.
These spent masses, which ceased to be reactive under the conditions of the Rochow reaction, remain reactive in air and their landfilling requires prior passivation treatment. The methods are numerous and generally consist in oxidizing the product either in air or in an aqueous medium. Thus, US Pat. Nos. 4,892,694 and 5,126,203 to General Electric propose stabilizing the spent masses in the form of pellets impregnated with an organic binder such as lignin. US patent 5,274,158 from the same company proposes to treat the residues by heating between 900 and 1,500 ° C. under an inert atmosphere and EP 0601,796 to heat between 400 and 800 ° C. in an oxygen atmosphere.
Other methods have been proposed to try to recycle the used masses into reusable products while avoiding their landfill. Thus, WO 95/27086 by Elkem describes the treatment of spent masses in an electric arc furnace to recover silicon and copper. Elkem's patent application EP 0786532 describes the manufacture of briquettes made of residues based on silicon mixed with cardboard, hydraulic cement and a ferro-alloy, and usable as metallurgical additive. Application EP 0794160 from the applicant describes the recycling of spent masses in the form of a refractory powder based on silicon nitride which, mixed with an organic binder, makes it possible to produce plugs for tap holes for blast furnaces or electric metallurgy ovens. However, due to the significant development of silicone production, it remains necessary to find other possibilities for recycling used materials.

Objet de l'inventionSubject of the invention

L'invention a pour objet un produit en poudre pour la protection des moules de coulée centrifuge des tuyaux de fonte constitué d'un mélange de poudres minérales et d'un agent inoculant de la fonte à base de silicium, caractérisé en ce qu'une partie au moins du silicium provient des masses usées de silicium issues de la synthèse des alkyl- ou aryl-halogénosilanes. L'agent inoculant peut être à base de ferrosilicium ou d'un autre alliage de silicium comportant par exemple de l'aluminium, du calcium, du baryum, du strontium, du manganèse et/ou du zirconium.
L'invention concerne également un procédé de fabrication d'un produit en poudre pour la protection des moules de coulée centrifuge des tuyaux de fonte consistant à:

  • a) traiter une masse usée issue de la synthèse des alkyl- ou aryl-halogénosilanes pour en éliminer l'étain et éventuellement le cuivre,
  • b) ajouter à la masse traitée de la poudre de silicium ou d'alliage de silicium pour ajuster sa teneur en silicium à une valeur prédéterminée,
  • c) incorporer éventuellement au mélange, si sa teneur en silice est inférieure à une valeur prédéterminée, une poudre minérale inerte vis-à-vis des autres composants, telle que la silice, le carbone ou le spath-fluor.
    • The subject of the invention is a powdered product for the protection of centrifugal casting molds for cast iron pipes, consisting of a mixture of mineral powders and a silicon-based cast iron inoculating agent, characterized in that a at least part of the silicon comes from spent silicon masses from the synthesis of alkyl- or aryl-halosilanes. The inoculating agent may be based on ferrosilicon or on another silicon alloy comprising for example aluminum, calcium, barium, strontium, manganese and / or zirconium.
    The invention also relates to a method for manufacturing a powdered product for the protection of molds for centrifugal casting of cast iron pipes, comprising:
  • a) treating a spent mass resulting from the synthesis of alkyl- or aryl-halosilanes in order to eliminate the tin and optionally the copper,
  • b) adding silicon or silicon alloy powder to the treated mass to adjust its silicon content to a predetermined value,
  • c) optionally incorporating into the mixture, if its silica content is less than a predetermined value, an inert mineral powder with respect to the other components, such as silica, carbon or fluorspar.

    • Description de l'inventionDescription of the invention

    Si elles contiennent de l'étain provenant du catalyseur utilisé dans la réaction de Rochow, les masses usées récupérées à la sortie du réacteur sont d'abord traitées, au moyen, par exemple, d'une solution d'acide sulfurique contenant de 15 à 50% en poids d'acide pur, à une température comprise entre 20 et 100°C. L'étain et le cuivre sont éliminés sous forme de sulfates qui peuvent être réutilisés. La fraction insoluble, c'est-à-dire la masse épurée est ensuite séchée et se présente alors sous la forme d'une poudre de granulométrie inférieure à 0,1 mm.
    Selon l'origine de la masse usée et des conditions de la réaction, la teneur en silicium non oxydé est très variable et cette variabilité est un obstacle majeur à son recyclage dans des applications industrielles exigeant un minimum de reproductibilité. Pour réaliser un produit de protection des moules de coulée des tuyaux de fonte, qui présente des propriétés d'emploi analogues à ceux couramment utilisés, il est nécessaire de corriger le titre en silicium par ajout de ferrosilicium ou d'un alliage de silicium contenant jusqu'à 5% d'un ou plusieurs éléments tels que le calcium, l'aluminium, le baryum, le strontium, le manganèse ou le zirconium, de manière à maintenir un pouvoir inoculant à peu près constant vis-à-vis de la fonte.
    On prépare ensuite le mélange final, d'une granulométrie inférieure à 200 µm, par addition d'une poudre minérale inerte contenant par exemple du carbone, du spath-fluor ou d'autres composés fluorés ou de la silice, en tenant compte de la silice déjà apportée par la masse usée, qui peut dans certains cas se révéler suffisante et éviter ainsi toute addition.
    Pour réaliser avec succès ces deux opérations successives de mélange, il convient de contrôler à chaque étape du procédé la qualité obtenue, ce qui exige de disposer à la fois d'un test d'évaluation du pouvoir inoculant du matériau de base et d'un test d'application spécifique pour la protection des coquilles de coulée centrifuge.
    Pour tester le pouvoir inoculant du matériau de base, c'est-à-dire le mélange de la masse usée épurée et de l'alliage inoculant au silicium d'appoint, on traite en four à induction un creuset de fonte par addition de 1% en poids de matériau de base, puis on coule dans un moule en sable pour obtenir des éprouvettes de différentes épaisseurs. On contrôle sur ces éprouvettes, par microscopie optique, l'épaisseur de trempe, c'est-à-dire l'épaisseur de la peau de structure perlitique autour du coeur de la pièce de structure ferritique.
    Pour évaluer de manière spécifique l'adéquation du produit final à la protection des coquilles de coulée des tuyaux, on coule de la fonte liquide dans un moule cylindrique fixe à axe vertical en métal fritté poreux, dont la partie extérieure est entourée d'une enveloppe étanche permettant le tirage au vide sur la partie extérieure du moule. Ce dispositif permet de maintenir sur la surface interne du moule la poudre protectrice de produit à tester, et d'éviter ainsi que cette poudre ne soit balayée par le flot de fonte liquide au moment de la coulée. Un noyau cylindrique en sable aggloméré placé en position coaxiale permet d'obtenir la forme torique simulant celle d'un tuyau. La face interne du moule est réalisée avec un angle de 2 degrés pour faciliter le démoulage. La qualité des produits testés est appréciée par rapport au temps de démoulage de la pièce sous la seule action de la gravité, et de la profondeur de trempe observée sur la peau extérieure de la pièce. Le test est réalisé avec un dosage constant de produit à tester de 200 g/m2. La fonte liquide nécessaire au test est traitée préalablement à 1550°C par ajout de 14 g/kg de fonte d'alliage nickel-magnésium à 15% de magnésium.    If they contain tin from the catalyst used in the Rochow reaction, the waste masses recovered at the outlet of the reactor are first treated, for example by means of a sulfuric acid solution containing from 15 to 50% by weight of pure acid, at a temperature between 20 and 100 ° C. Tin and copper are eliminated in the form of sulfates which can be reused. The insoluble fraction, that is to say the purified mass, is then dried and then takes the form of a powder with a particle size of less than 0.1 mm.
    Depending on the origin of the spent mass and the reaction conditions, the content of non-oxidized silicon is very variable and this variability is a major obstacle to its recycling in industrial applications requiring a minimum of reproducibility. To produce a protection product for the molds for casting cast iron pipes, which has properties of use similar to those commonly used, it is necessary to correct the silicon title by adding ferrosilicon or a silicon alloy containing up to '' at 5% of one or more elements such as calcium, aluminum, barium, strontium, manganese or zirconium, so as to maintain an almost constant inoculating power with respect to cast iron .
    The final mixture is then prepared, with a particle size of less than 200 μm, by adding an inert mineral powder containing, for example carbon, fluorspar or other fluorinated compounds or silica, taking into account the silica already supplied by the spent mass, which in certain cases may prove to be sufficient and thus avoid any addition.
    To successfully carry out these two successive mixing operations, the quality obtained should be checked at each stage of the process, which requires both an evaluation test of the inoculating power of the base material and a specific application test for the protection of centrifugal casting shells.
    To test the inoculating power of the base material, that is to say the mixture of the purified spent mass and the alloy inoculating with extra silicon, a melting crucible is treated in an induction furnace by adding 1 % by weight of base material, then poured into a sand mold to obtain test pieces of different thicknesses. The quenching thickness, that is to say the thickness of the skin of pearlitic structure around the core of the piece of ferritic structure, is checked on these test pieces, by optical microscopy.
    To specifically assess the suitability of the final product for the protection of the casting shells of pipes, liquid cast iron is poured into a fixed cylindrical mold with a vertical axis of porous sintered metal, the outer part of which is surrounded by an envelope waterproof allowing the vacuum to be drawn on the outside of the mold. This device makes it possible to maintain the protective powder of product to be tested on the internal surface of the mold, and thus to prevent this powder from being swept away by the flow of liquid cast iron at the time of casting. A cylindrical core of agglomerated sand placed in a coaxial position makes it possible to obtain the toric shape simulating that of a pipe. The internal face of the mold is produced at an angle of 2 degrees to facilitate demolding. The quality of the products tested is assessed in relation to the release time of the part under the sole action of gravity, and the depth of quenching observed on the outer skin of the part. The test is carried out with a constant dosage of product to be tested of 200 g / m 2 . The liquid cast iron required for the test is treated beforehand at 1550 ° C. by adding 14 g / kg of nickel-magnesium alloy cast iron to 15% magnesium.

    ExemplesExamples Exemple 1Example 1

    On effectue un premier essai en préparant une poudre de granulométrie comprise entre 50 et 200 µm d'un alliage de composition suivante (en poids): Si = 62,4%    Ca = 2,1%   Ba = 1,85%   Al = 0,91%   Mn = 0,26%   Zr = 0,11% solde Fe.
    Le pouvoir inoculant de cet alliage est testé en traitant avec 30 g d'alliage 3 kg de fonte Sorel fondue à 1400°C dans un four à induction, et en coulant cette fonte dans les 5 minutes suivant son traitement dans un moule en sable pour obtenir des éprouvettes d'épaisseur 20, 10, 5 et 2 mm. On constate que la structure des éprouvettes est entièrement perlitique pour les deux plus minces, l'épaisseur de perlite étant de 3 mm sur l'éprouvette d'épaisseur 20 mm et de 4 mm sur l'éprouvette d'épaisseur 10 mm.
    On prépare ensuite un mélange constitué de 90% en poids de l'alliage inoculant précédent et de 10% de poudre de silice de granulométrie comprise entre 50 et 100 µm. Ce mélange est testé en protection de coquilles dans un moule cylindrique vertical de diamètre 90 mm et de hauteur 130 mm, avec un noyau central en graphite de diamètre 70 mm. La pièce obtenue se démoule par gravité 20 s après la fin de la coulée et l'épaisseur de perlite sur la surface extérieure est de 2 mm.    A first test is carried out by preparing a powder with a particle size between 50 and 200 μm of an alloy of the following composition (by weight): Si = 62.4% Ca = 2.1% Ba = 1.85% Al = 0 , 91% Mn = 0.26% Zr = 0.11% balance Fe.
    The inoculating power of this alloy is tested by treating with 30 g of alloy 3 kg of Sorel cast iron melted at 1400 ° C in an induction furnace, and by casting this cast iron within 5 minutes following its treatment in a sand mold for obtain 20, 10, 5 and 2 mm thick test pieces. It can be seen that the structure of the test pieces is entirely perlitic for the two thinner ones, the perlite thickness being 3 mm on the 20 mm thick test piece and 4 mm on the 10 mm thick test piece.
    A mixture consisting of 90% by weight of the preceding inoculating alloy and 10% of silica powder with a particle size between 50 and 100 μm is then prepared. This mixture is tested for shell protection in a vertical cylindrical mold with a diameter of 90 mm and a height of 130 mm, with a central graphite core with a diameter of 70 mm. The part obtained is released by gravity 20 s after the end of the casting and the thickness of perlite on the external surface is 2 mm.

    Exemple 2Example 2

    Des résidus de la fabrication de dichlorométhylsilane ont été récupérés à la sortie d'un réacteur de synthèse et sont traités par une solution d'acide sulfurique pour en éliminer l'étain et le cuivre. La fraction insoluble recueillie et séchée se présente sous la forme d'une poudre de granulométrie inférieure à 50 µm, de composition (en poids): Si = 38%   FeSi2,4 = 21%   SiO2 = 24%   C = 9%   SiC = 3%    Al2O3 = 2%   Ti = 1%
    On mélange 40 g de cette poudre avec 60 g de ferro-silicium 75% de composition (en poids): Si = 76,3%   Al = 0,78%   Ca = 0,4%   le solde étant essentiellement du fer. Le mélange est testé en tant qu'inoculant dans les mêmes conditions que dans l'exemple 1. On constate que la structure des éprouvettes est totalement perlitique pour les épaisseurs 2 et 5 mm, et que l'épaisseur de perlite est respectivement de 3 et 2 mm pour les épaisseurs de 10 et 20 mm.
    Le mélange, sans ajout d'aucun autre produit, est ensuite testé comme produit de protection des coquilles de coulée de tuyaux dans des conditions identiques à celles de l'exemple 1. La pièce coulée se démoule 18 s après la fin de la coulée et l'épaisseur de perlite sur la face externe est évaluée à 1,5 mm. On constate donc que ce produit assure une protection légèrement meilleure que celui de l'exemple 1.    Residues from the manufacture of dichloromethylsilane were collected at the outlet of a synthesis reactor and are treated with a sulfuric acid solution to remove the tin and copper. The insoluble fraction collected and dried is in the form of a powder with a particle size less than 50 μm, of composition (by weight): Si = 38% FeSi 2.4 = 21% SiO 2 = 24% C = 9% SiC = 3% Al 2 O 3 = 2% Ti = 1%
    40 g of this powder are mixed with 60 g of ferro-silicon 75% of composition (by weight): Si = 76.3% Al = 0.78% Ca = 0.4% the balance being essentially iron. The mixture is tested as an inoculant under the same conditions as in Example 1. It can be seen that the structure of the test pieces is completely perlitic for the thicknesses 2 and 5 mm, and that the thickness of perlite is respectively 3 and 2 mm for thicknesses of 10 and 20 mm.
    The mixture, without the addition of any other product, is then tested as a product for protecting the pipe casting shells under conditions identical to those of Example 1. The casting is released from the mold 18 s after the end of the casting and the thickness of perlite on the external face is evaluated at 1.5 mm. It is therefore found that this product provides slightly better protection than that of Example 1.

    Claims (13)

    Produit en poudre pour la protection des moules de coulée centrifuge de tuyaux en fonte, constitué d'un mélange de poudres minérales et d'un agent inoculant de la fonte à base de silicium, caractérisé en ce qu'une partie au moins du silicium provient de masses usées de silicium issues de la synthèse des alkyl- ou aryl-halogénosilanes.Powder product for the protection of centrifugal pipe molds cast iron, consisting of a mixture of mineral powders and an inoculating agent of cast iron based on silicon, characterized in that at least part of the silicon comes from spent silicon masses from the synthesis of alkyl- or aryl-halosilanes. Produit selon la revendication 1, caractérisé en ce que l'agent inoculant est du ferrosilicium.Product according to claim 1, characterized in that the inoculating agent is ferrosilicon. Produit selon la revendication 1, caractérisé en ce que l'agent inoculant est un alliage de silicium comportant 5% au plus de l'un au moins des éléments aluminium, calcium, baryum, strontium, manganèse et zirconium.Product according to claim 1, characterized in that the inoculating agent is a silicon alloy comprising not more than 5% of at least one of the elements aluminum, calcium, barium, strontium, manganese and zirconium. Produit selon l'une des revendications 1 à 3, caractérisé en ce que la poudre minérale est de la silice.Product according to one of claims 1 to 3, characterized in that the powder mineral is silica. Produit selon la revendication 4, caractérisé en ce que toute la silice provient de la masse usée.Product according to claim 4, characterized in that all of the silica comes from the used mass. Produit selon l'une des revendications 1 à 3, caractérisé en ce que la poudre minérale contient du carbone.Product according to one of claims 1 to 3, characterized in that the powder mineral contains carbon. Produit selon l'une des revendications 1 à 3, caractérisé en ce que la poudre minérale contient un composé fluoré tel que le spath-fluor.Product according to one of claims 1 to 3, characterized in that the powder mineral contains a fluorinated compound such as fluorspar. Produit selon l'une quelconque des revendications 1 à 7, caractérisé en ce que sa granulométrie est inférieure à 200 µm. Product according to any one of Claims 1 to 7, characterized in that its particle size is less than 200 µm. Procédé de préparation d'un produit en poudre pour la protection des moules de coulée centrifuge des tuyaux de fonte, consistant à: a) traiter une masse usée issue de la synthèse des alkyl- ou aryl-halogénosilanes pour en éliminer l'étain et éventuellement le cuivre, b) ajouter à la masse traitée de la poudre de silicium ou d'alliage de silicium pour ajuster sa teneur en silicium à une valeur prédéterminée, c) incorporer éventuellement au mélange, si sa teneur en silice est inférieure à une valeur prédéterminée, une poudre minérale inerte vis-à-vis des autres composants. Process for the preparation of a powdered product for the protection of molds for centrifugal casting of cast iron pipes, comprising: a) treating a spent mass resulting from the synthesis of alkyl- or aryl-halosilanes in order to eliminate the tin and optionally the copper, b) adding silicon or silicon alloy powder to the treated mass to adjust its silicon content to a predetermined value, c) optionally incorporate into the mixture, if its silica content is less than a predetermined value, an inert mineral powder with respect to the other components. Procédé selon la revendication 9 caractérisé en ce que l'alliage de silicium est du ferrosilicium.Process according to Claim 9, characterized in that the silicon alloy is ferrosilicon. Procédé selon l'une des revendications 9 ou 10, caractérisé en ce que l'alliage de silicium contient au plus 5% en poids de l'un au moins des éléments aluminium, calcium, baryum, strontium, manganèse et zirconium.Method according to one of claims 9 or 10, characterized in that the alloy of silicon contains at most 5% by weight of at least one of the aluminum elements, calcium, barium, strontium, manganese and zirconium. Procédé selon l'une des revendications 9 à 11, caractérisé en ce que la poudre minérale incorporée est de la silice, du carbone ou un composé fluoré tel que le spath-fluor.Method according to one of claims 9 to 11, characterized in that the powder incorporated mineral is silica, carbon or a fluorinated compound such as fluorspar. Procédé selon l'une des revendications 9 à 12, caractérisé en ce que la poudre a une granulométrie inférieure à 200 µm.Method according to one of claims 9 to 12, characterized in that the powder has particle size less than 200 µm.
    EP99420004A 1998-01-16 1999-01-12 Powder for protecting centrifugal moulds for cast iron pipes and process for producing said powder Withdrawn EP0930113A1 (en)

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    FR9800628A FR2773728B1 (en) 1998-01-16 1998-01-16 POWDER PRODUCT FOR THE PROTECTION OF CENTRIFUGAL CAST MOLDS FROM CAST IRON AND POTENTIAL PREPARATION METHOD
    FR9800628 1998-01-16

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    CN106312070A (en) * 2016-08-09 2017-01-11 兰州理工大学 Carbon-based parting agent for sintering graphite jig by metallic matrix diamond tool and preparation method and using method thereof
    EP1575724B1 (en) * 2002-01-25 2018-08-01 Ferropem Products for the protection of continuous cast moulds for cast-iron pipes

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    CN100352576C (en) * 2006-05-23 2007-12-05 武汉重工铸锻有限责任公司 Molding sand and preparation method
    CN105081257A (en) * 2015-08-05 2015-11-25 苏州好洁清洁器具有限公司 Composite aluminum alloy pipe
    CN105886883B (en) * 2016-05-31 2017-08-04 含山县兴达球墨铸铁厂 Inovulant and preparation method thereof and the application in spheroidal graphite cast-iron

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    US6338753B1 (en) 2002-01-15
    FR2773728B1 (en) 2000-03-17
    FR2773728A1 (en) 1999-07-23
    JPH11277210A (en) 1999-10-12

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