DE2535302A1 - PROCESS FOR MANUFACTURING FIRED CERAMIC PRODUCTS WITH A CELLULAR STRUCTURE AND THE PRODUCTS OBTAINED THEREOF - Google Patents

Description

MÜLLEH-BOKE -GROENING 13IHJFIiL SCHÖN HERTEL

I * Λ Τ IO N T Λ NW A I.T K MÜNC1IKN - HHAUNHCiIWKIG - ΚΟΙ, Ν

G 2431 (Cas 3 8O3A)

L 7TH AUG. J975

GLAVERBEL-MECANIVER, Watermael-Boitsfort / Belgium

and
SOVITEC SA, Charleroi / Belgium

Process for the production of fired ceramic products with a cellular structure and the resulting products

Priority: August 9, 1974, Luxembourg, No. 70698

July 17, 1975, Great Britain Br. 30088/75

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BMO.NCIIKN BU SIElIKKTKTIi. 4 I-OII 8 (111720 KAUEL: UllKUÜl'AT TEL. <08U) 4710 71 »TELUX: Π-2Ϊ039

The invention relates to a method for producing fired Ceramic products or ceramic products with a cellular or cellular structure. The invention also relates to the ceramic products made in this way.

The term "ceramic" as used herein is not limited to clay and clay-based materials, which firing gives a permanent, hard form, but also for other inorganic, non-metallic substances, which can be made into durable objects by molding and firing.

Hard products with a cellular structure can be used in many ways, for example for thermal insulation and for Building purposes.

It is known to use different types of hard products with zelliger Produce structure by subjecting the material to a swelling process during the formation of the product. For example be on the known manufacturing procedures Referenced from foamed glass or clay products, in which by a heating treatment in the sintering or vitreous Mass gas bubbles are formed from air that was initially contained in the material, or from gas that was formed on the ground chemical decomposition of one or more constituents of the mass is released.

All known methods suffer from various disadvantages. They are used for the manufacture of mechanically strong cellular structures Not suitable for products and do not allow good control of the cell distribution properties. The products show generally have many intercommunicating pores and exhibit poor mechanical strength. The minor one Strength results from the fact that the gas tends to move away from where it was originally or was developed to penetrate into or through the cell matrix. This will either result in education caused by cracks in the matrix or the selection of the

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Matrix composition or physical dimensions and shape of the products are restricted.

The object of the invention now consists in specifying a method with which structures of different types are readily available Cellularity can be formed, and at the same time using different ceramic materials for Formation of the matrix, including those materials that give fired products with good mechanical strength, which are suitable, for example, for construction purposes, can be carried out.

The invention therefore relates to a process for the production of fired ceramic products with zelliger Structure, which is characterized in that one body or particles of a solid material which contain a gas or releasing a gas during heating to the temperature at which the ceramic material is fired and which during this heating change reversibly from the solid to a flowable state, in a mass the ceramic material distributed and the ceramic material with the bodies or particles distributed in it burns and then cools down.

This process leads to a product that has cells or cavities in those places where the distributed Bodies or particles were arranged. During the burning process, the material is subject to the dispersed body that is in a is transferred to the flowable state, the gas pressure exerted at these points and is thereby outwardly against the enveloping surface of the ceramic mass pressed.

The coating of the ceramic cell wall with the material the dispersed bodies or particles prevent or reduce the diffusion of the gas into the ceramic matrix. Therefore the tendency to form cracks is avoided or reduced. Depending on the type and amount of the die Distributed body of forming material can be the coatings

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on the cell walls contribute significantly to the mechanical strength of the end product.

The size and distribution of the cells or the cavities in the ceramic matrix can be determined by a suitable selection of the The size and distribution of the bodies or particles dispersed in the ceramic material prior to firing are reasonable narrow areas are predetermined. As a result, the process is versatile and enables the production of Ceramic products with different specific weights and / or different insulating properties.

In practicing the invention, it is suitable to use clay or clay-containing ceramic materials of the type suitable for used in the manufacture of bricks, blocks and other structural elements. The procedure can therefore be based on the Manufacture of fired elements are applied, which have good mechanical strength and which at the same time are relatively light in weight.

There are a variety of mineral compounds or compositions that which can be hardened by heating and which can be used in accordance with the invention. Lots of materials of this type are based on clay, silica, alumina or calcareous materials or magnesias. They include terracotta, earthenware and earthenware materials and stoneware materials.

The bodies that are dispersed in the mass of ceramic material can be granules or otherwise shaped pieces. she comprise a material that during firing in a flowable state, i.e. a liquid or plastic state, is transferred. This material flows in situ within the ceramic mass, partly due to the action of the originally contained in the bodies or during the Burning formed gas. The body can be designed in such a way that they under the action of the gas to a considerable extent swell or become inflated or otherwise

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significantly increase their volume.

According to preferred embodiments of the invention, the body are composed in such a way that they during burning only then pass into the flowable state after the ceramic material surrounding them hold together to such an extent that breaking open or the formation of cracks is prevented under the action of the forces caused by the trapped in the bodies Gas to be exercised.

It can thus be ensured that the matrix structure, even if not by applying external measures Expansion of the ceramic mass is prevented by the internal forces exerted by the gas will. In many cases there is a flow of material in the body from the center of the cells to the one around them Ceramic matrix. Furthermore, the final dimensions of the finished product can be predetermined within narrower limits will. In practicing the invention, however, such external ones can be used in any cases if desired Action to be taken. For example, you can use the ceramic mass appropriately increased during the firing or during at least the first part of the firing time Subject ambient pressure.

By a suitable selection of the ceramic composition can be achieved that the mass is able to to withstand internal forces exerted by the gas during an early stage of the combustion process, in which the ceramic mass is still at a relatively low temperature. Some hardening of the ceramic material can be reached before the firing stage.

The dispersed bodies preferably have a composition that results in at least one predominant A number of these bodies result in a continuous lining or an inner coating of the cells that are at the point this body are formed. This result can be done without

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further achieved through the use of bodies made of a material with temperature-dependent rheological properties so that the material while it is in the flowable state and subjected to the action of gas pressure is, results in a continuous cell lining or inner shell, which then maintains its uninterrupted Surface shape solidifies. The formation of cells or cavities, which are predominantly uninterrupted Having linings or inner coverings is advantageous, as this increases the thermal insulation properties and the strength of the product are promoted. Furthermore, the fact that the cell lining is not broken and is continuous, is an important factor in preventing the formation of cracks in the ceramic matrix, which be formed by an escape of the gas from the places of the dispersed bodies. Furthermore, the water permeability of the product is lower when the cells are lined in this way.

In certain embodiments of the invention the composition is an at least predominant number of the distributed body in such a way that after the flow of the material that occurs during firing, defining monocells in the fired product. Generally speaking, products that the monocells have better mechanical strength in relation to the amount of material from which these distributed bodies are formed. This monocell formation can be achieved if the physical form the body initially distributed in the ceramic mass is selected in a suitable manner, as will be explained in the following, for example, and / or if the material the body is brought to a sufficiently low viscosity during the burning and the expanded volume of gas sufficient to press the entire flowable material against the surrounding ceramic material until the flowable material solidifies.

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Preferably, at least some of the bodies initially distributed in the ceramic mass must have a bubble shape. Such Bodies contain gas bubbles. The presence of trapped gas volumes favors the formation of uninterrupted Cell linings. The fact that the volume of gas is present in the bodies from the start of burning is so far favorable, since this prevents or reduces the penetration of the gas into the ceramic matrix. Compared to Bodies in which the gas is released through a chemical reaction, the time for the formation of the end products is in this Case lower. These bladder bodies can, for example, each have a multicellular shape, i.e. they can have a Contain multitude of small gas bubbles. In addition to closed cells, they can also be a number of open cells exhibit. The bodies can be bodies made of a pre-expanded material.

According to certain embodiments of the invention, it is in the case of the bodies initially distributed in the ceramic material around preformed unicellular bodies. By using such The body can produce the products described above, in which the cells predominantly consist of monocells exist, can be achieved very easily. A particular advantage of using preformed unicellular bodies is the fact that the number, size and distribution of cells in the final product are predetermined within narrow limits can.

A wide variety of methods are known for forming hollow unicellular bodies which are softened by heating can be, for example small spherical or non-spherical bodies called "microballoons" and those for use in the method according to the invention are suitable.

In certain embodiments of the method according to the invention at least some of the bodies initially distributed in the ceramic material consist of a solid foam. Also in

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in these cases the bodies contain trapped gas volumes from the beginning of the burning on. The body can move with it very easily Using known procedures.

Advantageously, there are at least a few the body around gaseous particles or pieces of expanded material. With the help of well-known flatulence methods one can body with a very suitable shape that contain gas volumes, e.g. bodies in the form of solid foams, easily produce and mix with the ceramic material.

According to certain embodiments of the invention contain at least some of the bodies dispersed in the ceramic material produce a substance that evolves a gas during firing. These embodiments have the advantage that it is not necessary in the manufacture of the body, a swelling or To cause foaming of the body or to apply other measures to ensure that the body is trapped Gas included. The gas is released during normal firing of the ceramic material. Thus, these Embodiments can be carried out with a lower energy consumption and at a lower cost. As suitable substances, which develop a gas during the burning process should be mentioned in particular: urea, biuret and dimethylolurea and various metal salts from the categories of carbonates, bicarbonates, nitrates, nitrites, sulfates, sulfites, carbamates, Oxalates, formates and benzoates, especially the sodium, potassium, ammonium, calcium, magnesium and aluminum salts of these categories. Other suitable organic compounds that are incorporated into the formation of the gas during the firing step are, for example, melamine, glycerine, pentaglycerine, mellitic acid, adipic acid, aniline-p-sulfonic acid, Tetrabromaniline, trimethylglycerine, aminoquinoline, 5-methyl-resorcinol, nitroaminobenzoic acid, pyridinedicarboxylic acid, Nitrobenzonitrile, thiophenecarboxylic acid, trihydroxyanthraquinone and "Carbowax 1000".

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The invention also relates to methods of those described above Kind in which at least some of the bodies in the shape in which they were initially distributed in the ceramic material contain a combustible material that burns during the burning stage. Because of this burn a gas is not only formed, which removes the solid body, which is in a flowable state, from the solid Material drifts outwards, but heat is released during firing in the ceramic mass. This warmth supports the firing of the ceramic material. As a result, the firing is accelerated, or you can lower the furnace temperature Reduce. The combustion gases can favorably affect the properties of the fired product. For example, carbon dioxide increases the thermal insulation capacity. As very suitable flammable substances in the bodies that can be incorporated, which are distributed in the ceramic material, are in particular carbon, fine coal, e.g. coal dust, graphite, coke, lignite, slate containing flammable residues, tar, Charcoal, wood, for example bits of wood or sawdust. Other suitable combustible materials can be found in the area of synthetic polymeric substances. In this context, for example, polystyrene, polyurethane, polyester, Vinyl polymers, phenolic resins and epoxy resins are referred to. Other combustible materials included in the above distributed bodies include soft rubber and derivatives thereof, bituminous materials, such as Asphalt, and carbohydrates and carbohydrate derivatives, for example sugar, glycol, glycerine, cellulose and starch, a.

It will be understood that when a combustible substance is used in the composition of the dispersed bodies, that is Gas released during combustion act on the constituent or constituents that make up the lining of the cells is, so that the distribution of these components on the cell inner walls is supported. If such a flammable Material is used, it is therefore not always necessary

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agile to add another gas-evolving substance or other gas-evolving substances. However, one can add one or more such substances if this is necessary for any reason, for example, to increase the amount of gas released or to cause gas evolution before the Fuel starts to burn.

In preferred embodiments of the method according to the invention at least some of the bodies distributed in the ceramic material before firing contain a glassy material, that softens and flows while burning. Bodies made of vitreous or vitreous material lead to a number of important advantages. The glassy materials have viscosities over a wide temperature range for the required material flow are suitable. This makes it easier to set up a firing program (temperature / time) that is also suitable for the ceramic material of the matrix.

Another advantage of using glass bodies is that the vitreous material softens at a temperature which is higher than the temperature at which the hardening is normally used in the manufacture of bricks and ceramic materials used in other components. Thus, when the glass softens, the ceramic matrix is in a state in which it is easily able to withstand the cracking caused by the gas pressure.

In some methods of the invention, at least some include the body in the form in which it was initially in the Ceramic material are distributed, particles of a vitreous material held together by a binder substance will. Such bodies can be made very easily. It is not necessary that the glass material, for example the particles of soda-lime glass, become soft during this production. The production can therefore be relatively occur at low temperatures, i.e. at temperatures

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which are significantly lower than those for the production of Foam glass used. The glass particles can be made from broken glass or other waste glass, for example be. In the individual bodies, the glass particles can be held together with the help of various types of binding agent. These binders contain water, which may contain other ingredients, various adhesives, sodium silicate, Potassium silicate and sodium and potassium hydroxide. Other suitable binders are synthetic polymers Substances, in particular phenolic resins, polystyrene, polyurethane, vinyl polymers, polyesters, polyethers, silicones, various polycondensation products, for example urea-formaldehyde resins and phenol-formaldehyde resins, and condensates of urethanes, epoxies, polyesters and polyamines.

It will be understood that various binders, including some of those mentioned above, may be used during the firing of the ceramic material, in which the bodies containing such binders are distributed, burn or release a gas. if it is desirable or necessary that a gas be released during the burning process, it is often sufficient to enter the body incorporate a suitable binder, which also serves this additional purpose, so that no further gas-forming or combustible material is necessary.

If a binder is used that does not allow gas formation during firing, and if the bodies do not have another The bodies should contain any component or no other components which lead to such gas formation be made to contain gas from the start. For example, you can use a binder that has a Porous or cellular matrix forms, or one can use hollow bodies use which comprise a shell consisting of glass particles held together by the binder. On the other hand, if a binder is used that burns during firing or evolves a gas, or if the body has one or more other components

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which lead to sufficient gas development, solid bodies initially distributed in the ceramic matrix or massive, i.e. non-porous and non-cellular bodies.

The invention also relates to methods in which at least some of the bodies in the form in which they are initially in the Ceramic material are distributed, consist of an expanded vitreous material. The puffing or expansion of these bodies happens very quickly. Furthermore, expanded glass bodies have a relatively high expansion capacity. It can do without Difficulty Objects or particles made of expanded glass getting produced.

In certain embodiments of the invention, at least some of the bodies are contained in the form in which they are initially included in the ceramic material are distributed, particles of substances that during firing with the formation of a glassy React material, whereby these particles are held together with the help of a binder. This represents a very useful alternative to the use of bodies containing glass particles. The glass is during the Firing of the ceramic material is formed and forms the lining of the cells in the fired product. If you have particles When used from glass-forming substances, any of the binder substances can be used as the binder for these particles use those mentioned above in relation to bodies, the particles of vitreous material in a binder contain.

The bodies that contain glass-forming substances and a binder may contain amounts of gas or may consist of one Be formed material that contains a gas-evolving component or components, as in Reference has been made to the bodies comprising particles of preformed glass in a binder.

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From the above statements with regard to the type of body distributed in the ceramic material, it is understood that it it is not necessary that all bodies distributed in a given ceramic mass are of the same type. It also lies within the scope of the invention to use a mixture of bodies of different composition. For example some of the bodies dispersed in a given ceramic mass may comprise glass particles in a binder, while the remainder is made up of particles of glass-forming substances in a binder. As another example, you can some bodies are bodies made of foamed glass, while others are glassy bodies in the same ceramic mass Material and a combustible or other gas-releasing component.

Soda-lime glass is advantageously used as the vitreous material. When using such a material, the temperature in the heated mass preferably reaches during firing Values above 600 C.

Preferably the gas-containing or gas-evolving ones have Body in the ceramic material of such a size, shape and composition that the cells have a size in the range of 0.1 mm to 10 mm in the fired product. This size range includes that Cell sizes most appropriate to obtain the greatest benefits of the invention. In general, the size is the original body closely related to the size of the cells or cavities formed in the corresponding places, the difference being dependent in part on the amount of material in the bodies that make up the cell lining is used. The expansion of the body (if any) during burning is of course also a factor that affects cell size.

Preferably the bodies are selected such that the cells in the final fired product are of a size in the range from 0.1 to 3 mm. This has been found to be optimal for many types of products.

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The bodies incorporated into a given mass of ceramic material to be fired preferably have substantially the same size. This condition favors the workability of the mass, i.e. its deformation into the desired shape. However, to achieve a favorable ratio between the specific gravity of the end product and its compressive strength a mixture of bodies of different Particle size can be used. In this case, the bodies preferably have a particle size such as Shape and composition so that the cells in the final fired product have a size distribution such that the largest cell size is no more than ten times the smallest cell size.

Preferably the particle size, shape and composition of the bodies are such that the total cell volume of the fired product is 30 to 60 % of the total volume of the product. By adhering to this condition, it is possible to give the end product a low specific weight and good thermal insulation properties and at the same time to achieve compressive strength appropriate for building purposes.

Preferably at least some of the are in the ceramic material dispersed body made of a glassy material, and the heating takes place during firing in such a way that the vitreous material chemically interacts with the ceramic material surrounding it reacted. This chemical reaction improves the properties of the end product. In particular, a Union of the matrix with the lining of the cells, which increases the mechanical strength of the product favored. In particularly important embodiments of the In the invention in which such a chemical reaction takes place, a ceramic material is used for the matrix based on one or more silicates. These processes result in an end product, the cell lining of which is gen have a very high hardness and high mechanical strength.

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In the process according to the invention, the ceramic material used is advantageously a material based on aluminum oxide (Al ₂ O ₃ ), silicon dioxide (SiO ^), a SiIicat or silicates, a heat-resistant oxide or several heat-resistant oxides or a compound or several compounds of one or more substances of this kind. These materials are generally the main constituents of clay or refractory materials commonly used in the manufacture of various ceramic products such as terracotta (bricks), refractory bricks and the like, for which the method is very well suited.

When the ceramic material with the gas containing or gas When it is mixed into the constituent bodies, it may be in a loose, solid state. In this way one easily achieves a good distribution of the bodies in the mass of ceramic material.

The mixture of the ceramic material and the gas-containing or gas-forming bodies distributed therein can be prior to Burning can be brought into a predetermined shape. This can be done with the material before or after adding the body Water or other liquid medium can be mixed in a sufficient amount to form a slurry or paste with a suitable consistency. This paste can be made differently with the help of a mold Produce shaped elements, for example rectangular blocks, bricks, slabs or panels, which are then prepared in advance can be dried after firing.

Furthermore, it is possible to convert the ceramic products produced according to the invention into the predetermined ones after their completion To cut shapes, for example into blocks, plates or panels.

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The invention also relates to fired ceramic products with a cellular structure, which are characterized in that that at least some of the cells in the matrix are made of the ceramic material are at least partially lined with a solid material that has a softening temperature or a Has softening range below the temperature to which the ceramic material is heated for firing got to.

These ceramic products have useful properties and especially a favorable compressive strength / weight ratio. The presence of the more or less thick Cell lining adds to the mechanical strength. This is in part a consequence of the behavior of the cells lining material during the firing of the ceramic product. Furthermore, the cell lining can own Strength, which depends on the material and shape, add to the strength of the overall product.

The ceramic products according to the invention can be used for various Applications are used. For example, you can use them in the form of blocks or bricks to create of partitions or load-bearing walls or interior partitions. The ceramic product possesses useful Thermal insulation properties and in certain cases too Sound insulation properties. The thermal insulation capacity depends on the number, the dimensions and the distribution of the cells in the ceramic matrix. The preferred ceramic products according to the invention show in comparison with FIG known cellular ceramic products have a low porosity or moisture permeability.

The lining of each or at least the majority of the cells is preferably continuous and uninterrupted. In other words, each of the cells is completely covered with the lining material. This uninterrupted Lining is essential to the strength of the product and also improves water impermeability.

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The cells are advantageously predominantly around monocells which are individually surrounded by the ceramic material. Such monocells improve the insulation properties of the product and, depending on the amount of material lining the cells, give the product a good mechanical strength.

In other very satisfactory embodiments of the Invention defines a preponderant number of the locations in the ceramic matrix where a quantity of the cell lining material If the cell lining material is present, a plurality of individual cells is present. Products of this Kinds can be made very easily. It is preferably the one which forms a large number of individual cells Cell lining material around solid foam bodies. These foam bodies behave during the burning of the Product in such a way that the formation of articles is favored which has a favorable combination of properties have, which can be assigned to the manner in which the material lining the cells at the points is distributed within the matrix on which the cells are present.

In the most preferred product of the invention, the material lining the cells is a glassy material. That vitreous material or the vitreous material is particularly well suited to bring about the properties mentioned above, The vitreous material can form continuous uninterrupted linings that the trapped gas during the Tightly enclose the firing, which results in a substantial improvement in the strength of the end product Has.

According to very important embodiments of the ceramic products according to the invention, the cells are expanded by bodies Glass formed, which are distributed in the ceramic matrix. By using such bodies you can get the special benefits of the glass linings can be achieved easily and at very low cost.

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The material lining the cells is preferably soda-lime glass. This material is used for the sake of Cost and its softening properties during heating s to the temperature obtained during firing suitable ceramic materials is achieved, is preferred.

The gas in the cells of the fired product can be a gas that improves the insulation properties influenced. For example, the cells can contain carbon dioxide which favors the thermal insulation properties of the product. The type of gas and its pressure depends on the type of material incorporated into the ceramic matrix to form the lined cells and the firing conditions away. For example, the gas can be generated by burning a component which is initially in the ceramic matrix distributed bodies or formed by reaction between different solid components of such bodies, or as in the case of foam glass, the gas can be present in the bodies in the form of pores or cells.

The fired ceramic products of the present invention are characterized according to particular embodiments, that the cells have a size in the range of 0.1 to 10 mm. Most preferably, the cells have a size im Range from 0.1 to 3.0 mm. If the other conditions are kept constant, the products that meet these conditions show generally the most favorable relationship between specific weight and compressive strength.

The invention also relates to fired ceramic products of the type defined above in which the range of cell size is such that the largest cell size is not is more than ten times the smallest cell size. This creates a favorable relationship between the compressive strength and the specific weight of the product.

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Another factor that affects the compressive strength of the product, is the ratio of the total cell volume to the total volume of the finished product. Preferably own the cells have a volume which represents 30 to 60% of the total volume of the product. The relation between the compressive strength of the product, its specific weight and its thermal insulation properties, if the other parameters are kept constant, this is best if this condition is observed.

Finally, the invention relates to fired ceramic products of the type described above, which are used as cell lining material contain a vitreous material that has chemically reacted with the surrounding ceramic material. The appearance such a chemical reaction generally promotes the ultimate strength of the product. The cell lining possesses a vitroceramic nature with considerable rigidity and is forming a monolithic structure connected to the matrix.

A ceramic material is preferably used on the basis of aluminum oxide, silicon dioxide, silicate (s), a refractory oxide or refractory oxides or one Compound or compounds of one or more such substances. Such ceramic materials are for products on best suited for building and other such purposes. The advantages of these ceramic materials arise especially when the cell linings are glassy in nature.

The fired ceramic products according to the invention can have any physical form depending on the intended use. For example, closes the invention such products in the form of blocks or bricks suitable for building purposes, or in the form of panels or panels used for cladding or to create lightweight partitions.

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Further embodiments, advantages and objects of the invention result from the following examples, in which reference is made to the attached schematic figures:

Fig. 1 shows an enlarged sectional view of a portion of a ceramic product before firing,

Fig. 2 shows a similar view of the same area of the ceramic product after firing;

3 shows an enlarged sectional view of part of another fired ceramic product according to the invention;

Fig. 4 is a similar view of a portion of another fired ceramic product according to the invention and

Fig. 5 is a similar view of part of another ceramic product according to the invention.

example 1

Bricks according to the invention are prepared from a clay or a clay-containing material which contains 40% by weight Kaolinite, 40% by weight quartz sand, 8% by weight lime, 4% by weight iron oxide and various secondary substances such as Contains mica or feldspar. This clay-containing material is dried, ground and then mixed with 25% by volume of water mixed to form a paste. Then 900 (bulk volume) expanded glass granules with a particle size are mixed in the range of 2 to 6 mm with 500 l of the paste. The glass granules are granules made of expanded soda-lime glass of the following composition:

72% SiO ₂ , 14% Na ₂ O, 8% CaO, 4% MgO, 0.9% Al ₃ O ₃ , remainder: impurities.

The mixture obtained in this way is kneaded and then extruded into a strand with a rectangular cross-section, after which the strand is cut lengthways into individual bricks ..

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The bricks are placed in a drying device and dried for 7 days. Own in this state the dried bricks have the internal structure shown in Fig. 1 of the accompanying drawings, the comprises the clay-containing matrix 1 in which granules 2 of expanded glass are distributed. These bricks will then placed in a conventional brick kiln, in which they are gradually heated to a temperature of 1100 C in the course of 24 hours, with the remainder Water evaporates from the bricks. The bricks are kept at 1100 C for 12 hours and then slowly cooled to room temperature. The total treatment time from the beginning of the heating in the oven to the end of the The cooling period is 48 hours.

During the heating of the bricks to a temperature of more than 500 C, physical and chemical reactions occur, which transform the kaolinite through molecular dissociation and harden the clay-containing matrix firmly. The glass the puffed granules soften and become fluid when the temperature reaches 750 ° C, followed by this softening the pressure exerted by the gas within the granules causes migration of the glass to the periphery of that by the granules occupied places causes, so that viscous envelopes or cell linings on the surrounding ceramic material form. At an even higher temperature, the glass of the shell material unites with the silicates of the hard ones Matrix, which increases the strength of the end product. During the firing, the clay-containing matrix, before the pressure is transferred to the matrix due to the softening of the glass, sufficiently hard and coherent, so that it can resist cracking under the action of the pressure exerted by the gas that is contained in the glass granules.

After cooling, the bricks are cut up and it is found that they are predominantly those indicated in FIG have a cellular structure. Inside the hard ceramic

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Matrix 3 gas-containing monocells 4 are distributed. Each of these cells is covered with a covering layer 5 made of glassy silicates lined. In most cases this layer is chemically connected to the matrix 3 and therefore does not show a well-defined one outer boundary layer. This boundary layer is therefore shown in the drawing by a dashed line. During the firing of the bricks, their lime content decreases, with the result that the bricks have a have very good weather resistance.

The total cell volume is about 60% of the total volume of bricks, which are much lighter in weight than non-cellular bricks of the same composition and the same size. However, the bricks have a high compressive strength. For the applied Materials and process conditions becomes a brick / Volume ratio of 60% as optimal for a combination of a favorable weight reduction and a good mechanical Strength. The specific gravity of non-cellular bricks of the same composition is 1.7 g / ccm, while the specific gravity of the cellular bricks produced according to this example Is 0.83 g / ccm. The cellular bricks have good insulation properties. They have a coefficient of thermal conductivity of not more than 0.25 kcal / m / h / C, while the corresponding value for the non-cellular bricks 0.65 kcal / m / h / ° C. The compressive strength of the cellular bricks is more than 150 kg / cm, while that of the non-cellular bricks is only 120 kg / cm amounts to.

Example 2

Example 1 is repeated using the following modifications. The dried milled clayey material is mixed with sodium carbonate before adding the expanded glass granules and the water, whereby the latter Substance used in an amount of 1 part by weight per 1000 parts by weight of the clay-containing material. The sodium carbonate

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is used to improve the flowability of the paste formed admitted. The expanded glass granules with a particle size in the range from 6 to 10 mm have the same composition as those used in Example 1 and are used in relation to the clayey material in the same ratio, as indicated in Example 1, added and mixed intimately with the material. The dry mixture formed is then after processed the procedure described in Example 1 using 25% by volume of water to form a paste. To After kneading, the paste is shaped into bricks, which are then, as described in Example 1, dried and fired , however, a firing temperature of 950 C is maintained for 40 hours. After cooling down, the Bricks cut up, and it is found that they predominantly have a cellular structure, as shown in Fig.3 is reproduced. At the location of each glass body in the fired clay matrix 6 there is a group of gas-filled Cells 7, which are formed by glass walls or glass layers 8, which in turn contain a gas-filled cell 9. The total cell volume, expressed as a percentage of the total product volume, is approximately 55%. The specific Weight of the bricks is the same as that produced according to Example 1, while having a compressive strength in the range of 130 kg / cm. During firing, the matrix becomes hard enough and holds up well enough together to withstand the internal forces exerted by the gas so that the matrix does not crack occurs.

Example 3

Refractory bricks are prepared by burning a mixture of clay and fireclay grains, which are used in a weight ratio of 50:50, at a high temperature.

The composition of the clay is similar to that given in Example 1, although this clay does not contain lime. In which Fireclay is crushed pre-fired clay,

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which serves to reduce the plasticity of the mass. After firing, the brick has the following composition:

53.2% by weight SiO ₂ , 42.1% by weight Al ₂ O ₃ , 2.08% by weight Fe ^ OV, remainder: impurities.

The starting materials mentioned are processed into a paste according to the procedure of Example 1, i.e. by using the material is comminuted and the solid is kneaded with 20% by volume of water. Then expanded glass granules are formed with a particle size in the range from 0.2 to 2 mm added and distributed in the paste, per volume of the Paste 1 bulk volume of the granules used. The glass has the same composition as that used in Example 1 Material. The mixture obtained is shaped into bricks in a press.

After drying for a month, the bricks are placed in a kiln at a high temperature, in which the bricks are gradually heated to a temperature of 1200 C. There are similar physical ones and chemical reactions like those given in Example 1, including hardening of the clay-containing matrix, starting at around 500 C, and softening and expanding the Glass granules that set in at around 750 ° C. The one after the end of the firing process and the subsequent cooling The bricks obtained are cut up and show a structure of the type shown in Fig. 4. Inside The fired clay matrix 10 contains cells 11, each of which has a glass lining 12. These linings are uninterrupted and continuous, which is important for the strength of the bricks. Furthermore, a such continuous lining increases the impermeability to water. There could be no cracking in the ceramic matrix can be determined, indicating that the matrix is not exposed to any significant internal gas pressure at the location of the cells before it was held together firmly enough to withstand such pressure.

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The bricks have a cell volume of 45%, based on the total volume of the bricks. The bricks have a specific gravity of 1.2 g / cc compared to 2.0 g / cc for non-cellular bricks of the same Composition, a thermal conductivity of 0.5 kcal / m / c / hour compared to 1.0 kcal / m / ° c / h. in the case of the non-cellular Bricks, and a compressive strength of 275 kg / cm compared to 250 kg / cm with the non-cellular bricks is achieved.

Example 4

This example illustrates the manufacture of insulating ceramic panels with light weight necessary for the manufacture or lining the inner walls of a fireplace are suitable.

The panels, which have dimensions of 60 40 χ 4 cm, is obtained starting from fireclay concrete.

The chamotte concrete is prepared from a mixture of the following composition: 80% by weight molochite chamotte and 20% by weight of a refractory concrete, which consists of hydrated calcium aluminates and is sold under the name "Secar" by the Societe des Ciments Lafarge (147 Avenue General De Gaulle, Neuilly-sur-Seine / France). The composition of the molochite (apart from impurities) is the following: 54% by weight SiO ₂ , 42% by weight Al ₃ O ₃ , 1.7% by weight alkali and 0.7% by weight iron oxide.

After the above-mentioned composition has been mixed and kneaded with 20% by volume of water, 900 l (bulk volume) of expanded glass beads are added to 600 l of the moist paste. The glass beads have a particle size in the range from 0.1 to 1 mm. The glass has the following composition: 73% by weight SiO ₃ , 15% by weight Na ₂ O, 10% by weight CaO, 1% by weight Al ₂ O ₃ , 0.05% by weight Fe ₃ O ₃ , remainder: Impurities. The paste is formed into molds to make the panels to be produced. The unfired products are then used during

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Dried in a dryer for 15 days.

The dried, unfired panels are then fired in an oven in which their temperature is gradually increased to 1300 ° C. over the course of 20 hours, after which this temperature is maintained for a further 24 hours. The panels are then slowly cooled to room temperature. The panels retain their physical shape and dimensions during firing. It can be seen that the panels have an internal structure which corresponds to that shown in FIG. The uninterrupted glass linings 12 are, as in the case of the previous example, in firm contact with the fired concrete matrix surrounding them at all points in which no crack formation can be observed. The cell / panel volume ratio is 55 %. The fired panels have a specific weight of 1.0 g / ccm and a thermal conductivity of 0.4 kcal / m / h / C. The corresponding values for non-cellular panels that only consist of the same matrix material are: Specific weight 1.9 g / ccm, thermal conductivity 1.0 kcal / m / h / ° C.

The boards are resistant to high temperatures and very good for lining suitable for the vertical and top walls of a fireplace. The handling and attachment of the panels is due to their light weight very simple and convenient. Your thermal insulation properties allow heat to be retained in the middle of the stove.

The panels produced according to this example can, after further treatments, for example after enamelling, used as decorative panels for cladding walls and for other purposes.

Example 5

This example concerns the manufacture of cladding panels from lightweight stone material. Preparing the stone slabs starting from a natural clay containing mica

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of the following composition: 3% by weight kaolinite, 33% by weight Mica and 33% by weight quartz sand. Such clays can be found in different natural geological locations, for example in France in the area of St Amand. After firing, the material has the following chemical Composition:

72% by weight SiO ₂ , 23% by weight Al ₂ O ₃ , 3% by weight K ₃ O, 1% by weight CaO, 1% by weight MgO and 1% by weight Fe ₃ O ₃ .

After the clay has dried and crushed, 10% by volume of water is added to form a slightly moist paste. While the paste is being kneaded, expanded glass granules with a particle size in the range from 100 μm to 1 mm are added, 1 bulk volume of the granules being used per volume of the paste. The glass of these granules has the following composition:

54.5% by weight SiO ₂ , 7.5% by weight B ₂ O ₃ , 17.4% by weight CaO, 14.3% by weight Al ₀ O ₃ , 4.8% by weight MgO, remainder: impurities .

The paste prepared with the grains of expanded glass dispersed therein is placed in molds of suitable shape and pressed in two stages. In the first stage, a pressure of 10 kg / cm is applied to avoid any trapped To expel air. In the second stage the pressure is increased to 150 kg / cm. This pressure can be applied in a vacuum will. The unfired panels are then stacked in a ventilation room and there for several days heated.

After this drying treatment, the unfired Plates loaded onto trolleys and introduced into a known tunnel oven, in which the plates progressively up a temperature between 1250 and 1300 ° C, i.e. the firing temperature necessary for the production of stoneware will. Firing at this temperature is carried out for about 30 hours, after which the plates are slowly brought to room temperature be cooled down.

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The internal structure of the stone slabs finally obtained corresponds to that indicated in FIG. In the stone matrix there are cells 14, each of which has an uninterrupted glass lining 15 which contains small cells 16. the Linings are supported at all points by the surrounding stone matrix 13. The panels are free inside of cracks. They show a low specific weight (1.4 g / ccm, compared to 2.25 g / ccm for plates without the expanded glass granules were produced), although they are waterproof and wear-resistant - have the characteristic of common stone products of this type. The cell / plate volume ratio is about 42%. The panels have a compressive strength of 250 kg / cm.

The light stone slabs can be used to clad walls and as floor coverings, they can also be used for Lining of autoclaves that are used in the chemical industry are used.

The method described in these examples can be used to advantage for the production of other stone articles, no matter which deformation methods are used. For example, one can use this method for the production of Use ceramic drainage pipes or sanitary stoneware.

Example 6

This example concerns the production of sanitary stoneware, i.e. basins or sink units made of fine, hard material calcareous earthenware.

A starting paste is prepared using a mixture containing 3 8% by weight of a clay from Provins, France, Contains 25% by weight kaolin, 21% by weight quartz sand, 10% by weight calcined flint and 6% by weight lime. This mixture is finely ground and then mixed with 30% by volume of water to form a slurry.

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Hollow glass spheres (for example "microballoons") with a diameter between 0.5 and 2 mm are then added to the slurry, for which 1000 l (bulk volume) of the spheres are used per 1300 l of the slurry. The composition of the glass is as follows: 74.7% by weight SiO ₂ , 6.4% by weight Na ₂ O 0.5% by weight K ₂ O, 5.6% by weight Al ₂ O ₃ , 9, 6% by weight B ₂ O ₃ and 0.9% by weight CaO, remainder: impurities. The slurry is intimately mixed with a small amount of sodium carbonate and sodium silicate to facilitate removal of the mass from the molds to be used.

The mixture is brought into the desired shape using conventional techniques. One leaves the surface of the molded Objects solidify before the objects are removed from the molds and dried.

After drying, the shaped objects are fired in a tunnel kiln, in which their temperature slowly rises II80 C is brought. Then they will be during at least Maintained at this temperature for 24 hours. The fired items that have predominantly a structure such as they are reproduced in FIG. 4, have a ratio of the volume of the lines / volume of the objects of about 40%. The objects are then enamelled in the usual way.

The presence of microcells formed by the walls of the hollow glass spheres in the structure of the finished stoneware Significantly reduces the weight of the products, making them easier to transport and install. the Products have a specific weight of 1.3 g / ccm compared to 2.0 g / ccm in the case of products in which Inside no glass-lined cells are distributed.

Example 7

Example 1 is repeated using the following changes. The used granules contain expanded glass per 1000 l (bulk volume) of the glass granules 50 kg

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Carbon. The firing program used includes a progressive increase in the temperature of the bricks during 24 hours at 1000 C. Apart from these conditions, the composition of the unfired bricks is the same and their subsequent treatment exactly as specified in Example 1 conditions. The in burns while it is burning the carbon contained in the glass granules dispersed in the clay matrix slowly developing a considerable amount of heat and gas. The heat developed in the bricks in this way supports the firing process and enables it a reduction in the fuel consumption of the furnace.

Examination of the internal structure of the fired bricks shows that the structure is variable. At many There are glass bodies inside the brick, whereby the bricks have a structure as in Example 1 is described with reference to FIG. 2, while the remaining locations are predominantly those in Example 3 shows the structure explained with reference to FIG. The cell / brick volume ratio is about 60%. The ceramic matrix shows no detectable cracks.

The finished bricks have essentially the same specific weight and the same thermal conductivity and the same compressive strength as the bricks produced according to Example 1. Due to the lower of energy to be supplied externally during the * burning, the production costs are somewhat lower in the case of this example than in the case of the bricks produced according to Example 1.

Example 8

Bricks are prepared using the clay or clay material described in the example. After drying and Crush the material and mix it with 25% by volume of water to form a paste. This paste is made in a kneading device introduced, after which one compound

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solid bodies containing glass particles and carbon particles and which have a particle size in the range from 2 to 6 mm, in an amount of 900 l (bulk volume) of the body for every 500 liters of paste added. The bodies consist of glass grains with a particle size between 60 and 150 μm, an equal amount by weight of carbon particles same particle size and 3% by weight calcium carbonate as a binder. The calcium carbonate serves both as a binder for the particles as well as a gas releasing agent or propellant.

The bricks made from the kneaded paste are dried and then fired, for which the in Example 7 complies with the specified conditions. As described in this example, physical and chemical reactions take place, which when heated to more than 500 C lead to strong solidification lead to the clayey matrix. During the firing of the bricks, the binder decomposes in the distributed ones Bodies producing carbon dioxide. The carbon burns with a corresponding amount of heat the places where it is distributed in the matrix. As in the previous example, the glass softens after the temperature has reached 750 C, after which a migration of the glass in the fluid state towards the cell walls takes place so that the cells of the fired product are provided with a continuous glass lining.

The fired bricks have an internal structure similar to that of the material in the previous example is, in which case there is a cell / brick volume ratio of about 55%. Most cells have a chemical bond with the glass lining the surrounding ceramic matrix takes place. No detectable cracks can be found in the ceramic matrix.

As in the case of the previous example, the Heat development within the bricks during firing, a significant saving in fuel consumption.

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need of the oven. The bricks of this example can be made at an even lower cost than the bricks of the previous one Example be produced, since one comminuted to produce the body to be distributed in the ceramic matrix Use broken glass or other crushed waste glass.

Example 9

This example concerns the manufacture of lightweight ceramic tiles or floor tiles. These products are obtained from a natural clay consisting of equal parts by weight of kaolinite, quartz sand and mica, which is fired to a material with the following composition: 70% by weight SiO ₂ , 18% by _{weight Al 2} O ₃ , 4% by weight -% K ₂ O, 5% by weight MgO, 1% by weight CaO and 2% by weight Fe ₃ O ₃ . After drying and crushing the clay, it is mixed with 10% by volume of water to form a relatively moist paste and kneaded with an equal volume of composite bodies, which have a particle size in the range from 100 μm to 1 mm and consist of agglomerated glass components and a gas-evolving component Means exist. The glass components are sand, sodium carbonate and borax in amounts that are suitable for forming a glass with the following composition: 72% by weight SiO ₂ , 12% by weight B ₅ O ₃ , 13% by weight Na ₂ O and lesser amounts of impurities. As a gas-generating agent, sodium nitrate is present in an amount of 2% by weight, based on the glass components.

The kneaded paste is molded into the desired shape of the plates by applying a pressure of 100 kg / cm or deformed floor slabs. After removal from the molds, the unfired products are stored in one for 15 days Dried airy storage room.

The dried panels are then fired in a conventional tunnel kiln, in which the products are gradually added be heated to a temperature of 1300 ° C, i.e. the

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Formation of ceramic products required firing temperature. During the firing, the glass components melt and form a viscous glass that under the action of the gas formed by the decomposition of sodium nitrate at the interfaces of the places within the ceramic matrix where the dispersed bodies were located. The firing temperature of 1300 C is maintained for 36 hours, after which the products are slowly cooled to room temperature.

When examined, the fired products obtained show a structure that in part consists of groups of cells of the Has type as described in Example 2 with reference to FIG. 3, and partially mono cells with small Has cells in the lining layer, as in Example 5 are described with reference to FIG. The products are light in weight and very good suitable for cladding walls or for use as floor coverings for buildings. They have a cell / product volume ratio of about 45%.

The process of this example can also be used for the production of other objects, for example ceramic pipes or sanitary products, be used. The fired ceramic products can, if necessary, be enamelled on the surface will.

Example 10

This example concerns the production of lightweight ceramic insulation panels, which are suitable for the interior lining of stoves or ovens. The plates have the dimensions 50 50 χ 5 cm and are built on the basis of fireclay concrete.

The fireclay concrete is a mixture of 80% quartz aggregates and molochite, which is a clayey fireclay (composition 54% by weight SiO ₂ , 42% by weight

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^A1 2 ° 3 » ^{1) 7} % by weight alkali, 0.7% by weight iron oxide plus impurities) and 20% fireclay concrete, as it is called" Secar "by the Societe des Ciments Lafarge, Neuilly-sur-Seine , France.

After mixing and kneading these ingredients with 20% by volume of water, small bodies containing glass-forming substances and having a particle size in the range from 200 μm to 2 mm are distributed in a ratio of 750 1 (bulk volume) of the body per 600 1 of the Paste in the paste. The glass components are sand, sodium carbonate, calcium carbonate, dolomite and feldspar, which are present in such amounts that a glass of the following composition results after firing: 73.6% by weight SiO ₂ , 17.2% by weight Na ₂ O, 5.37% by weight CaO, 3.67% by weight MgO and 0.9% by weight AlpO-, remainder: impurities. The composition from which the small bodies are formed also contains wood chips in an amount of 60 kg per 100 kg of the glass-forming substances.

The paste with the small bodies scattered in it is shaped into the desired panels, after which the shaped unfired objects are dried for 8 days.

After drying, the objects are placed in an oven, in which they are gradually heated to a temperature of 1300 C. which is then maintained for 24 hours. The fired products will then slowly rise Cooled to room temperature.

The refractory concrete hardens during firing. The wood chips burn with the development of considerable gas and gas Heat quantities. At higher temperatures, the glass-forming substances melt and form a viscous glass, the under the action of the pressure of said gas is pressed against the periphery of the places in the ceramic matrix of the bodies is occupied. Investigation of the burned

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Products shows that they have a structure that is predominantly corresponds to that described in Example 2 with reference to FIG. The cell / product volume ratio is about 50%. The plates have a specific gravity of 1.2 g / cc compared to 2.0 g / cc for the non-cellular ones Slabs made of the same refractory concrete, and have a thermal conductivity of 0.5 kcal / m / h / ° C while the non-cellular plates have a corresponding value of 1.0.

The heat released by the combustion of the wood chips inside the products favors the even firing treatment of the entire ceramic mass.

In a modification of the above procedure, polystyrene granules are used in place of the wood chips. In a similar way You can also use various other combustible plastic materials.

Due to their low weight and their insulating properties, the panels are very good for laying floors and suitable for cladding the walls and ceilings of houses.

Example 11

This example concerns the manufacture of lightweight ceramic tiles or floor tiles. The plates are obtained from a natural clay which contains equal amounts of kaolinite, quartz sand and mica and which can be fired into a ceramic material with the following composition: 70% by weight SiO ₂ , 18% by weight Al ₂ O ₃ , 4% by weight -% K ₂ O, 5% by weight MgO, 1% by weight CaO and 2% by weight Fe ₂ O ₃ .

After drying and crushing, the clay is 10% by volume Water mixed and made into a paste. During the process of kneading the paste, small compound ones are made Bodies containing glass granules are added to the paste in an equal volume (bulk volume). the

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Composite bodies have a particle size in the range from 100 ρ to 1 mm and consist of glass granules with a particle size in the range from 20 to 100 μm, urea, sodium silicate (38 ° Be) and water. The urea is present in an amount of 2% by weight, based on the weight of the glass, while 6 l of the sodium silicate solution and 4.5 l of water are used per 20 kg of glass. The glass has the following composition: 70.4% by weight SiO ₂ , 12.78% by _{weight Na 2} O, 12.14% by weight CaO, 1.77% by weight MgO, 1.92% by weight Al ₂ Oo, remainder: impurities.

The paste with the small composite bodies dispersed therein is then made suitable under a pressure of 100 kg / cm molded forms pressed. After this deformation, the unfired, molded panels are in one for 15 days Dried airy storage room.

The panels are then fired in a conventional manner in a tunnel kiln in which the panels are progressively raised to a temperature of 1300 ° C, i.e. the firing temperature that is necessary for the formation of the ceramic products. During the When the products are heated to the firing temperature, the urea distributed in the small bodies decomposes with the formation of gas. At the same time or at a later point in time, the glass in the shell of this hollow body softens, whereupon the granules melt together. The softened glass is pressed outwards under the pressure of the gas trapped in the bodies, so that the glass of each body eventually forms a monolithic glass envelope that is within the ceramic matrix forms a cell as shown in Figs.

The plates have a low specific weight (1.5 g / ecm compared to 2.2 g / ccm in the case of plates made in No distended bodies inside) and a compressive strength of 225 kg / cm. The cell ratio is about

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Example 12

By modifying the procedure described in Example 11, lightweight ceramic panels are made. According to this amendment as described in Example 11, small composite bodies are produced from a composition, which contains glass granules, urea, sodium silicate and water, whereupon the granules undergo an initial swelling treatment be subjected to a heating zone in which the bodies are heated to a temperature of 1050 ° C. During this heating the urea decomposes, releasing gas. During this pretreatment, the glass in the envelopes softens the glass granule and is driven outwards under the pressure of the enclosed gas. The sodium silicate connects chemically with the glass. The bodies are cooled while the glass solidifies. The obtained pretreated Bodies are hollow and each include a hollow glass envelope. These pre-inflated bodies then become equal Manner how the small composite bodies of Example 11 are used, i.e., the pre-inflated hollow bodies introduced into the paste, which is then shaped, dried and fired as described in Example 11.

The internal structure of the stone slabs obtained corresponds predominantly to that shown in FIGS. The plates are free of internal cracks and have a compressive strength of 250 kg / cm.

The method described can be used to advantage in the manufacture of other stone products or sanitary products will.

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Claims (39)

Claims 1. A method for the production of fired ceramic products with a cellular structure, characterized in that that bodies made of a solid material which contain a gas or are heated to the temperature in which the ceramic material is fired, release a gas and which is reversible from the during heating solid in a flowable state, distributed in a mass of the ceramic material and the ceramic material burns with the bodies scattered in it and then cools down. 2. The method according to claim 1, characterized in that the bodies are composed such that they during of firing only pass into the flowable state after the ceramic material surrounding them has settled has solidified to such an extent that it is able to withstand the forces causing the formation of fractures or cracks to resist exerted by the gas trapped in these bodies. 3. The method according to claim 1 or 2, characterized in that the bodies are composed so that at least a vast majority of the bodies in the cells that are formed at the sites of these bodies are uninterrupted Form continuous linings or cladding layers. 4. The method according to claim 3, characterized in that at least a predominant number of the body in such a way is composed that it flows into the fired after the flow of the material, which takes place during firing Form product monocells. 5. The method according to any one of the preceding claims, characterized in that at least some of the body 609808/0 9 53 in the form in which they are initially distributed in the ceramic material have a bubble shape. 6. The method according to claim 5, characterized in that at least some of the bodies in the form in which they are initially are distributed in the ceramic material, are deformed into unicellular bodies. 7. The method according to any one of the preceding claims, characterized characterized in that at least some of the bodies are initially distributed in the ceramic material consist of a solid foam. 8. The method according to any one of the preceding claims, characterized characterized in that at least some of the bodies in the form in which they are initially distributed in the ceramic material are particles or pieces of an expanded material containing gas. 9. The method according to any one of the preceding claims, characterized in that at least some of the body in the Form in which they are initially distributed in the ceramic material, contain a substance which during the Burning develops a gas. 10. The method according to any one of the preceding claims, characterized in that at least some of the body in the Form in which they are initially distributed in the ceramic material, contain a combustible material that during burns during the burning process. 11. The method according to any one of the preceding claims, characterized in that at least some of the bodies are glassy Contain material that softens and flows during firing. 609808/0953 12. The method according to claim 11, characterized in that at least some of the bodies in the form in which they are initially dispersed in the ceramic material comprise particles of a vitreous material supported by a binder substance be held together. 13. The method according to claim 11 or 12, characterized in that that at least some of the bodies in the form in which they are "initially distributed in the ceramic material, made of expanded consist of glassy material. 14. The method according to any one of the preceding claims, characterized in that at least some of the body in the Form in which they are initially distributed in the ceramic material, held together with a binder Include particles of substances which react during firing to form a glassy material. 15. The method according to any one of claims 11 to 14, characterized in that soda-lime glass is used as the vitreous material used. 16. The method according to claim 15, characterized in that the ceramic material during firing on a Heated to a temperature of more than 600 ° C. 17. The method according to any one of the preceding claims, characterized in that the body is of such a size The shape and composition are such that the cells formed in the fired product range in size from 0.1 mm to 10 mm. 18. The method according to claim 17, characterized in that the bodies have such a size, shape and composition that the cells formed in the fired product have a size in the range from 0.1 to 3 mm . 609808/0 953 19. The method according to claims 17 or 18, characterized in, that the bodies are of such a size, shape and composition that those in the fired product cells formed have a size in a range where the largest cell size is not more than ten times the smallest cell size. 20. The method according to any one of claims 17 to 19, characterized in that that the size, shape and composition of the body is such that the total cell volume in the Fired product is 30 to 60% of the total volume of the product. 21. The method according to any one of the preceding claims, characterized characterized in that at least some of the bodies distributed in the ceramic material are made of a vitreous material and the heating during the firing takes place in such a way that the vitreous material of the body is chemically reacts with the surrounding ceramic material. 22. The method according to claim 21, characterized in that the ceramic material is a material on the basis of a or more silicates. 23. The method according to any one of the preceding claims, characterized in that a material is used as the ceramic material based on aluminum oxide, silicon dioxide, one or more silicates, one or more fire-resistant Oxides or one or more compounds of one or more substances of this type are used. 24. Fired ceramic product with a cellular structure, thereby characterized in that at least some of the cells in the matrix of the ceramic material are at least partially covered with a are lined with solid material that has a softening temperature or a softening range below the Has temperature to which the ceramic material had to be heated for the purpose of firing. 609808/0953 25. Fired ceramic product according to claim 24, characterized in that that the lining of at least a majority of the cells is uninterrupted and continuous is. 26. Fired ceramic product according to claim 24 or 25, characterized characterized in that the cells are predominantly monocells, which are individually from the ceramic material are wrapped. 27. Fired ceramic product according to claim 24 or 25, characterized in that in a predominant number the places within the ceramic matrix where a quantity of the material lining the cells is present, this amount of the material lining the cells forms a multitude of individual cells. 28. Fired ceramic product according to claim 27, characterized in that that the amounts of the material lining the cells, which defines a plurality of individual cells, are in the form of solid foam bodies. 29. Fired ceramic product according to one of claims 24 to 28, characterized in that the cell lining Material a glassy material is present. 30. Fired ceramic product according to claim 29, characterized in that characterized in that the cells are defined by bodies of expanded glass distributed in the ceramic matrix are. 31. Fired ceramic product according to claim 29 or 30, characterized in that the lining material Soda-lime glass is present. 32. Fired ceramic product according to one of claims 24 to 31, characterized in that the cells have a size in the range from 0.1 to 10 mm. fi D 9 B 0 8/0 9 5 3 33. Fired ceramic product according to claim 32, characterized in that that the cells have a size in the range of 0.1 to 3.0 mm. 34. Fired ceramic product according to claim 32 or 33, characterized in that the range of the cell size is such is that the largest cell size is no more than ten times the smallest cell size. 35. Fired ceramic product according to one of claims 24 to 34, characterized in that the total volume of Cells make up 30 to 60% of the total volume of the product. 36. Fired ceramic product according to one of claims 24 to 35, characterized in that the cell lining Material is a vitreous material that chemically reacts with the ceramic material surrounding it Has. 37. Fired ceramic product according to one of claims 24 to 36, characterized in that the ceramic material a material based on alumina, silica, one or more silicates, one or more heat-resistant oxides or one or more compounds of one or more substances of this type. 8. Fired ceramic product according to one of Claims 24 to 37, characterized in that it is in the form of a block, a brick, a plate or a board Has. 39. Fired ceramic product with cellular structure, available according to a method of claims 1 to 23. 609808/0953 Blank page