DE102005030518B4 - Process for the preparation of mullite - Google Patents
Process for the preparation of mullite Download PDFInfo
- Publication number
- DE102005030518B4 DE102005030518B4 DE200510030518 DE102005030518A DE102005030518B4 DE 102005030518 B4 DE102005030518 B4 DE 102005030518B4 DE 200510030518 DE200510030518 DE 200510030518 DE 102005030518 A DE102005030518 A DE 102005030518A DE 102005030518 B4 DE102005030518 B4 DE 102005030518B4
- Authority
- DE
- Germany
- Prior art keywords
- mullite
- sio
- temperature
- sol
- green body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/16—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay
- C04B35/18—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay rich in aluminium oxide
- C04B35/185—Mullite 3Al2O3-2SiO2
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/62605—Treating the starting powders individually or as mixtures
- C04B35/62645—Thermal treatment of powders or mixtures thereof other than sintering
- C04B35/62655—Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3217—Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3231—Refractory metal oxides, their mixed metal oxides, or oxide-forming salts thereof
- C04B2235/3244—Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3418—Silicon oxide, silicic acids, or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
- C04B2235/54—Particle size related information
- C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
- C04B2235/5445—Particle size related information expressed by the size of the particles or aggregates thereof submicron sized, i.e. from 0,1 to 1 micron
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
- C04B2235/54—Particle size related information
- C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
- C04B2235/5454—Particle size related information expressed by the size of the particles or aggregates thereof nanometer sized, i.e. below 100 nm
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/74—Physical characteristics
- C04B2235/79—Non-stoichiometric products, e.g. perovskites (ABO3) with an A/B-ratio other than 1
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Nanotechnology (AREA)
- Physics & Mathematics (AREA)
- Structural Engineering (AREA)
- Inorganic Chemistry (AREA)
- Composite Materials (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Crystallography & Structural Chemistry (AREA)
- Thermal Sciences (AREA)
- Silicates, Zeolites, And Molecular Sieves (AREA)
- Compositions Of Oxide Ceramics (AREA)
Abstract
Verfahren
zur Herstellung von Mullit, bestehend aus den Schritten:
(i)
Suspendieren von Aluminiumoxidpulver in einem wäßrigen SiO2-Sol,
wobei die SiO2-Partikel einen Durchmesser von
5 bis 20 nm aufweisen,
(ii) Gefriergranulieren der in Schritt
(i) erhaltenen Suspension durch Versprühen der erhaltenen Suspension
bei einer Temperatur von mindestens –5°C, und
(iii) Sintern des
in Schritt (ii) erhaltenen Granulats oder eines daraus hergestellten
Grünkörpers bei
einer Temperatur zwischen 1050°C
und 1600°C.Process for the preparation of mullite, consisting of the steps:
(i) suspending alumina powder in an aqueous SiO 2 sol, the SiO 2 particles having a diameter of 5 to 20 nm,
(Ii) freeze granulating the obtained in step (i) suspension by spraying the resulting suspension at a temperature of at least -5 ° C, and
(iii) sintering the granules obtained in step (ii) or a green body produced therefrom at a temperature between 1050 ° C and 1600 ° C.
Description
Die vorliegende Erfindung betrifft ein Verfahren zur Herstellung von Mullit.The The present invention relates to a process for the preparation of Mullite.
Mullit (3Al2O3·2SiO2) ist ein wichtiger, kristalliner Bestandteil von Gefäß- und Baukeramiken und von feuerfesten Werkstoffen. Man unterscheidet Sinter-Mullit, der aus festen Ausgangsmaterialien durch eine Festkörperreaktion hergestellt wird, Schmelz-Mullit, der Phasen umfaßt, die aus Schmelzen und über eine nachfolgende definierte Erstarrung prozessiert werden, und chemischen Mullit, der über eine chemische Fällung und anschließende Kristallisation gebildet wird.Mullite (3Al 2 O 3 · 2SiO 2 ) is an important crystalline component of vitrified and structural ceramics and refractory materials. A distinction is made between sintered mullite prepared from solid starting materials by a solid state reaction, melt mullite comprising phases processed from melts and subsequent defined solidification, and chemical mullite formed by chemical precipitation and subsequent crystallization ,
Im allgemeinen wird Sinter-Mullit unter Verwendung herkömmlicher Pulvermischmethoden hergestellt, in denen Aluminumoxid- und Siliziumoxidpulver gemischt und bei hohen Tempe raturen von über 1600°C gesintert werden. Nach dem bekannten Verfahren hergestellte Mullit-Partikel weisen einen so großen Durchmesser auf, daß diese in einem weiteren Arbeitsschritt auf eine zur Verwendung geeigneten Größe gemahlen werden müssen, um hochfeine Pulver zu erhalten.in the Generally, sintered mullite is made using conventional Powder mixing methods are made in which alumina and silica powder mixed and sintered at high temperatures of over 1600 ° C. After this Mullite particles produced by known methods have such a large diameter on that this in a further step to a suitable for use Size ground Need to become, to get very fine powders.
Mullit hat zahlreiche vorteilhafte Eigenschaften, die ihn zur Verwendung für Feuerfestmaterialien geeignet erscheinen lassen. Dabei sind insbesondere der hohe Schmelzpunkt, die geringe Deformation unter Last, die geringe Wärmeausdehnung, der hohe Schermodul und günstige Oxidations- und Korrosionseigenschaften auch unter extremen chemischen Bedingungen zu nennen. Zwei bekannte Arten von mullithaltigen Feuerfestmaterialien sind Schamotte und aluminiumoxidreiche Steine.mullite has many beneficial properties that make it suitable for use suitable for refractory materials let appear. In particular, the high melting point, the low deformation under load, the low thermal expansion, the high shear modulus and cheap Oxidizing and corrosion properties even under extreme chemical conditions to call. Two known types of mullite-containing refractory materials are chamotte and high alumina stones.
Weitere Anwendungsgebiete für Mullit liegen auf dem Gebiet von Strukturkeramiken, beispielsweise zur Herstellung von Tiegeln, Schutzrohren und Thermoelementröhrchen. Desweiteren sind Mullit-Schutzschichten bekannt, die auf Materialien mit geringer Oxidations- und Korrosionsbeständigkeit aufgetragen werden. Ein weiteres Einsatzgebiet sind Glaskeramiken, Porzellan und Katalysatorträger.Further Application areas for Mullite are in the field of structural ceramics, for example for the production of crucibles, thermowells and thermocouple tubes. Furthermore, mullite protective coatings based on materials are known be applied with low oxidation and corrosion resistance. Another field of application are glass ceramics, porcelain and catalyst carriers.
Aus
der
Die
Aus
Aus Kong Deyu et al., Preparation of nano-SiO2-coated Al2O3 concentrated suspension and its gel casting, Journal of the Chinese Ceramic Society, 2004, Band 32, Nr. 4, S. 442–447, ist ein Verfahren zur Herstellung von Mullit bekannt, bei dem Al2O3 in einem SiO2-Sol dispergiert wird. Das Produkt, das aus SiO2-beschichteten Al2O3-Teilchen besteht, wird durch „Gelcasting" weiter zu einem Grünkörper verarbeitet.From Kong Deyu et al., Preparation of nano-SiO 2 -coated Al 2 O 3 concentrated suspension and its casting, Journal of the Chinese Ceramic Society, 2004, Vol. 32, No. 4, pp. 442-447, is a A method for producing mullite is known in which Al 2 O 3 is dispersed in a SiO 2 sol. The product, which consists of SiO 2 -coated Al 2 O 3 particles, is further processed by gel casting into a green body.
Aus dem Artikel von Wu et al., Continuous Fiber reinforced mullite matrix composites by sol-gel processing. I. Farbication and Microstructures, Journal of Materials Science, Band 32, Nr. 13, S. 3361–3362, ist ein Verfahren zur Herstellung von keramischen Verbundmaterialien auf Basis einer Mullit-Matrix bekannt, wobei zur Bildung des Mullits SiO2-Sol mit alpha-Al2O3-Pulver oder AlO(OH)-Sol versetzt wird. Der dadurch erhaltene Verbundwerkstoff wird unter Heißpressen bei 1300°C bis 1550°C gebrannt.From the article by Wu et al., Continuous Fiber Reinforced mullite matrix composites by sol-gel processing. I. Farbication and Microstructures, Journal of Materials Science, Vol. 32, No. 13, pp. 3361-3362, a method for the production of ceramic composite materials based on a mullite matrix is known, wherein for forming the mullite SiO 2 sol with alpha-Al 2 O 3 powder or AlO (OH) sol is added. The resulting composite material is fired under hot pressing at 1300 ° C to 1550 ° C.
Schließlich ist aus dem Artikel von Wheat et al., Synthesis of Mullit by a freeze-dry process, Ceramurgia International, Januar-März 1979, Band 5, Nr. 1, S. 42–44, ein Verfahren zur Synthese von Mullit bekannt, bei dem SiO2-Sol mit einer geeigneten Menge Al2(SO4)3-Lösung versetzt wird, um die Stöchiometrie von Mullit zu erhalten. Die Lösung wird in flüssigen Stickstoff eingesprüht, gefriergetrocknet und das Produkt bei 1400°C gebrannt.Finally, from the article by Wheat et al., Synthesis of Mullite by a freeze-dry process, Ceramurgia International, January-March 1979, Vol. 5, No. 1, pp. 42-44, a process for the synthesis of mullite is known, adding a suitable amount of Al 2 (SO 4 ) 3 solution to the SiO 2 sol to obtain the stoichiometry of mullite. The solution is sprayed into liquid nitrogen, freeze-dried and the product fired at 1400 ° C.
Der vorliegenden Erfindung liegt die Aufgabe zugrunde, ein Verfahren zur Herstellung von Mullit bzw. eines Mullit-Grünkörpers oder nicht gesinterten Mullit-Granulats bereitzustellen, das die Nachteile des Stands der Technik überwindet. Insbesondere soll ein Verfahren bereitgestellt werden, mit dem auf einfache Art und Weise, ohne aufwendige Ausrüstung, umweltfreundlich und mit geringem Energieaufwand Mullit hergestellt werden kann.Of the The present invention is based on the object, a method for the production of mullite or a mullite green body or non-sintered mullite granules to provide that overcomes the disadvantages of the prior art. In particular, a method is to be provided with which simple Way, without expensive equipment, environmentally friendly and Mullite can be produced with low energy expenditure.
Diese Aufgabe wird erfindungsgemäß gelöst durch ein Verfahren zur Herstellung von Mullit, umfassend die Schritte:
- (i) Suspendieren von Aluminiumoxidpulver in einem wäßrigen SiO2-Sol, wobei die SiO2-Partikel einen Durchmesser von 5 bis 20 nm aufweisen,
- (ii) Gefriergranulieren der in Schritt (i) erhaltenen Suspension durch Versprühen der erhaltenen Suspension bei einer Temperatur von mindestens –5°C, und
- (iii) Sintern des in Schritt (ii) erhaltenen Granulats oder eines daraus hergestellten Grünkörpers bei einer Temperatur zwischen 1050°C und 1600°C.
- (i) suspending alumina powder in an aqueous SiO 2 sol, the SiO 2 particles having a diameter of 5 to 20 nm,
- (Ii) freeze granulating the obtained in step (i) suspension by spraying the resulting suspension at a temperature of at least -5 ° C, and
- (iii) sintering the granules obtained in step (ii) or a green body produced therefrom at a temperature between 1050 ° C and 1600 ° C.
Dabei ist bevorzugt, daß der Grünkörper durch Verpressen des in Schritt (ii) erhaltenen Granulats hergestellt wird.there is preferred that the Green body through Compressing the granules obtained in step (ii) becomes.
Im Rahmen der vorliegenden Erfindung wird unter einem Grünköper ein Körper verstanden, der aus einem Pulver oder Granulat gepreßt (trockengepreßt, kaltisostatisch, etc.) oder aus einem Schlicker gegossen und anschließend getrocknet wird.in the Frame of the present invention is under a green body body understood that pressed from a powder or granules (dry pressed, cold isostatic, etc.) or poured from a slurry and then dried becomes.
Bevorzugt weisen die SiO2-Partikel einen Durchmesser von 8 bis 15 nm auf.The SiO 2 particles preferably have a diameter of 8 to 15 nm.
Eine Ausführungsform ist dadurch gekennzeichnet, daß die Partikel des Aluminiumoxidpulvers einen Durchmesser von 400 bis 700 nm aufweisen.A embodiment is characterized in that the Particles of alumina powder have a diameter of 400 to 700 nm.
Bevorzugt ist vorgesehen, daß das Versprühen in Schritt (ii) bei einer Temperatur von mindestens –20°C oder tiefer durchgeführt wird.Prefers is provided that the spray in step (ii) at a temperature of at least -20 ° C or lower carried out becomes.
Besonders bevorzugt ist, daß das Gefriergranulieren in Schritt (ii) ein Einsprühens der erhaltenen Suspension in einem mit flüssigem Stickstoff gefüllten Behälter umfaßt.Especially it is preferred that the Freeze granulation in step (ii) spraying the resulting suspension in one with liquid Nitrogen filled container includes.
Auch wird vorgeschlagen, daß das Sintern bei einer Temperatur zwischen 1100 und 1200°C durchgeführt wird.Also It is suggested that the Sintering is carried out at a temperature between 1100 and 1200 ° C.
Zum Versprühen der erhaltenen Suspension kann ferner vorgesehen sein, diese in einem Sprühturm zu verdüsen, dessen Innenraumtemperatur beispielsweise unter –20°C liegt. Die Vorteile bei der Verwendung von flüssigem Stickstoff sind, daß nur äußerst kleine Eiskristalle entstehen und der Einfrierprozeß sehr schnell abläuft. Die Trocknung des Granulats kann beispielsweise auch in einem Wirbelstromtrockner bei vorzugsweise etwa 60 bis etwa 120°C erfolgen. Optional erfolgt das Trocknen des Granulats unter Vakuum.To the spray The obtained suspension may further be provided in a spray tower to thaw, whose interior temperature is below -20 ° C, for example. The advantages of using from liquid Nitrogen is that only extremely small Ice crystals are formed and the freezing process is very fast. The Drying of the granules can, for example, in an eddy current dryer preferably at about 60 to about 120 ° C take place. Optional drying the granules under vacuum.
Aus dem Granulat oder Grünkörper kann durch Sintern bei einer Temperatur zwischen 1050°C und 1600°C ein erfindungsgemäßer Mullit hergestellt werden.Out the granules or green body can through Sintering at a temperature between 1050 ° C and 1600 ° C, an inventive mullite getting produced.
Überraschenderweise wurde festgestellt, daß mit dem erfindungsgemäßen Verfahren ein Mullit-Grünkörper bei geringen Temperaturen von 1050°C bis 1600°C gesintert werden kann, was gegenüber den herkömmlichen Verfahren, bei denen das Sintern regelmäßig bei Temperaturen über 1600°C durchgeführt wird, zu deutlichen Energieeinsparungen führt. Ferner ist das erfindungsgemäße Verfahren auf einfache Art und Weise, das heißt insbesondere ohne aufwendige Herstellung der Ausgangsprodukte oder komplizierte Prozeßführung, durchführbar. Das erfindungsgemäße Verfahren kann in einer einfachen Apparatur durchgeführt werden. Da als Ausgangskomponente lediglich wäßriges Silika-Sol und Aluminiumoxidpulver eingesetzt werden, ist das Verfahren auch äußerst umweltfreundlich, im Vergleich zu ebenfalls bekannten Sol-Gel-Verfahren, die mit Tetraethoxyorthosilan arbeiten.Surprisingly was found to be with the method according to the invention a mullite green body at low temperatures of 1050 ° C up to 1600 ° C can be sintered, which is opposite the conventional one Processes in which sintering is carried out regularly at temperatures above 1600 ° C, leads to significant energy savings. Furthermore, the method according to the invention in a simple way, that is, in particular, without consuming Production of raw materials or complex process control, feasible. The inventive method can be carried out in a simple apparatus. Da as the starting component only aqueous silica sol and alumina powder are used, the process is also extremely environmentally friendly, in comparison to likewise known sol-gel process, which with tetraethoxyorthosilane work.
Wesentliche Vorteile des erfindungsgemäßen Verfahrens liegen darin, daß durch die Auswahl entsprechender Ausgangsstoffe Mullite höchster Reinheit hergestellt werden können, ebenso wie gezielte Mullitphasen und Mischkristalle. Schließlich ist mit dem erfindungsgemäßen Verfahren eine gezielte Einstellung der Partikelgrößen möglich.basics Advantages of the method according to the invention lie in that through the selection of appropriate starting materials Mullite highest purity can be produced as well as targeted mullite phases and mixed crystals. Finally, with the method according to the invention a targeted adjustment of particle sizes possible.
Der Schritt des Gefriergranulierens liefert ein Granulat. Dieses Granulat kann ohne weiteren Verfahrensschritt zu Mullit-Granulat gesintert und anschließend zu einem Grünkörper aus Mullit mit anschließender Sinterung weiterverarbeitet werden, um einen Mullit-Formkörper zu ergeben. Andererseits kann das durch das Gefriergranulieren erhaltene Granulat zunächst, insbesondere durch Trockenpressen, in einen Grünkörper gebildet und anschließend gesintert werden, um ebenfalls einen Mullit-Formkörper zu ergeben.Of the Freeze granulation step delivers granules. This granulate can be sintered without further process step to mullite granules and subsequently to a green body Mullite with subsequent Sintering be further processed to a mullite molding result. On the other hand, the granules obtained by freeze granulation first, especially by dry pressing, formed in a green body and then sintered to give also a mullite molding.
Die Vorteile des erfindungsgemäßen Verfahrens scheinen unter anderem darin begründet zu sein, daß das eingesetzte Silika-Sol einen äußerst kleinen Partikeldurchmesser aufweist.The Advantages of the method according to the invention Among other things, this seems to be due to the fact that the used Silica sol a very small Particle diameter has.
Nach dem Sintern liegt der erhaltene Mullit in hochfeiner Pulverform vor und kann ohne weitere Zwischenschritte für die Herstellung von Keramikbauteilen und dergleichen verwendet werden.To sintering, the resulting mullite is in a very fine powder form before and can without further intermediate steps for the production of ceramic components and the like can be used.
Neben der Herstellung eines 3/2-Mullits (3Al2O3·2SiO2) können je nach Mischungsverhältnis auch andere bekannte Mullite, wie 2/1-Mullit (2Al2O3·SiO2) hergestellt werden. Ferner können dem erfindungsgemäßen Mullit Zuschlagstoffe beigemischt werden, insbesondere Metalloxide, wie ZrO2, um beispielsweise ein Zirkoniamullit (z. B. 46% Al2O3, 17% SiO2, 37% ZrO2) herzustellen. Der so herstellbare Zirkoniamullit wird bevorzugt in der glas- und metallverarbeitenden Industrie eingesetzt.In addition to the preparation of a 3/2 mullite (3Al 2 O 3 .2SiO 2 ), depending on the mixing ratio, it is also possible to prepare other known mullites, such as 2/1-mullite (2Al 2 O 3 .SiO 2 ). In addition, it is possible to admix additives to the mullite according to the invention, in particular metal oxides such as ZrO 2 , in order to produce, for example, a zirconium gemulite (eg 46% Al 2 O 3 , 17% SiO 2 , 37% ZrO 2 ). The Zirkoniamullit thus produced is preferably used in the glass and metal processing industry.
Claims (7)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE200510030518 DE102005030518B4 (en) | 2005-06-29 | 2005-06-29 | Process for the preparation of mullite |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE200510030518 DE102005030518B4 (en) | 2005-06-29 | 2005-06-29 | Process for the preparation of mullite |
Publications (2)
Publication Number | Publication Date |
---|---|
DE102005030518A1 DE102005030518A1 (en) | 2007-01-04 |
DE102005030518B4 true DE102005030518B4 (en) | 2008-07-31 |
Family
ID=37545012
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE200510030518 Expired - Fee Related DE102005030518B4 (en) | 2005-06-29 | 2005-06-29 | Process for the preparation of mullite |
Country Status (1)
Country | Link |
---|---|
DE (1) | DE102005030518B4 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017064177A1 (en) * | 2015-10-13 | 2017-04-20 | Ceramtec Gmbh | Production of ceramics without piezo-electric properties in an aqueous environment |
CN111108077A (en) | 2017-09-26 | 2020-05-05 | 德尔塔阀门公司 | Hydrogel injection molding formulations for ceramic products |
CN113429983B (en) * | 2021-06-23 | 2022-05-10 | 应急管理部天津消防研究所 | High-fire-resistance transparent fireproof gel, preparation method thereof and composite fireproof glass |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0543581A1 (en) * | 1991-11-16 | 1993-05-26 | Foseco International Limited | Ceramic material |
-
2005
- 2005-06-29 DE DE200510030518 patent/DE102005030518B4/en not_active Expired - Fee Related
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0543581A1 (en) * | 1991-11-16 | 1993-05-26 | Foseco International Limited | Ceramic material |
Non-Patent Citations (3)
Title |
---|
KONG DEYU u.a.: Preparation of nano-SiO2-coated AI203 concentrated suspension and its gel casting. Journal of the Chinese Ceramic Society, 2004, Vol. 32, No. 4, S. 442-447. (abstract) INSPEC (online). In: EPOQUE, Accession No. 8122299 * |
Wheat T.A., Sallam E.M.H., Chaklader A. C.D.: Synthesis of mullite by a freeze-dry process. Ceramurgia International, Januar-März 1979, Vol.5, No. 1, S. 42-44, (abstract) INSPEC (online). In: EPOQUE, Accession No. 1455580 * |
WU J.: JONES F.R., JAMES P.F.: Continuous fibre reinforced mullite matrix composites by sol-gel processing. I. Fabrication and microstructures Journal of Materials Science, Vol. 32, No. 13, S. 3361-3362. (abstract) INSPEC (online). In: EPOQUE, Accession No. 5654547 * |
Also Published As
Publication number | Publication date |
---|---|
DE102005030518A1 (en) | 2007-01-04 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP3371129B1 (en) | Sintered zirconia mullite refractory composite material, method for the production thereof and use of the same | |
DE3022213A1 (en) | CERAMIC MOLDED BODY WITH EUTECTICAL STRUCTURAL COMPONENTS AND METHOD FOR THE PRODUCTION THEREOF | |
EP1671766A2 (en) | Method of making a ceramic crucible | |
EP3383565B1 (en) | Method for producing refractory composite particles and feeder elements for the foundry industry, corresponding feeder elements and uses | |
DE2134072A1 (en) | Process for the production of objects from silicon nitride | |
WO2006034836A1 (en) | Porous structure | |
DE2724352A1 (en) | METHOD FOR MANUFACTURING A MOLDED BODY FROM A CERAMIC MATERIAL | |
EP3630701A1 (en) | Method for producing insulating material or an insulating product for the refractory industry, corresponding insulating materials and products, and uses | |
DE102005030518B4 (en) | Process for the preparation of mullite | |
DE69631093T2 (en) | INORGANIC, POROUS SUPPORT FOR A FILTRATION MEMBRANE AND PRODUCTION METHOD | |
EP3492437B1 (en) | Composite material comprising at least one first material and particles, whereby the particles have a negative thermal expansion coefficient alpha, and adhesive material comprising the composite material | |
EP0406549A2 (en) | Process for producing carbon bonded refractory ceramic bodies | |
EP1611066B1 (en) | Method for producing a siliceous granular material | |
DE102006011224B4 (en) | Slip and ceramic composite produced therewith | |
DE60301068T2 (en) | FIRE-RESISTANT BASED ON POLYCRYSTALLINE ALUMINUM OXIDE | |
DE3536407C2 (en) | ||
EP2748119B1 (en) | Titanium diboride granules as erosion protection for cathodes | |
DE4225623A1 (en) | Process for the preparation of powdery materials for the injection molding of ceramic materials and their use | |
EP0479253B1 (en) | Process for the production of large sized bodies serving as lining, especially for a soda-lime-silica melting plant | |
DE3744692C2 (en) | Silicon nitride powder and process for its preparation | |
DE2300547B2 (en) | Process for the production of a ceramic material | |
DE2357733A1 (en) | Fibre reinforced ductile metal or alloy - prepd from a mixt of metal and fibre-forming substance which is compacted and hot deformed | |
DE1471418C (en) | Process for the production of refractory materials based on zirconium oxide and aluminum oxide | |
DD290773A7 (en) | PORCELAIN SINTERED MATERIAL OF HIGH STRENGTH AND METHOD FOR THE PRODUCTION THEREOF | |
DE2846839A1 (en) | Dispenser nozzle for continuously cast steel - has outer sheath of chamotte or alumina with sialon insert |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
OP8 | Request for examination as to paragraph 44 patent law | ||
8364 | No opposition during term of opposition | ||
R119 | Application deemed withdrawn, or ip right lapsed, due to non-payment of renewal fee |
Effective date: 20120103 |