DE102008001176B4 - Shaped body and method for producing a shaped body - Google Patents

Abstract

The present invention relates to a process for the production of a shaped body and a shaped body, in particular a mold plate, comprising the components cement, fly ash, aluminum oxide (AL2O3), iron oxide (Fe2O3) and anhydrite, wherein the constituents have the following composition: 20-40 wt. % Cement, 40-70% by weight flyash, 5-15% by weight alumina, 0-5% by weight iron oxide and 0-5% by weight anhydrite.

Description

The The present invention relates to a molding, in particular a molding plate, cement, fly ash, alumina and a method of manufacture of such moldings.

in the Building materials sector and in the construction industry are becoming increasingly demanding placed on the components used. In particular made of concrete Components are not just for load-bearing structures comprising reinforcing elements, but also serve as sound-absorbing elements, for example for noise barriers or similar Walls.

Sound-absorbing components are for example from the DE 20 2006 008 233 U1 . DE 103 38 213 A1 . DE 100 20 955 A1 or off DE 39 16 299 A1 known. Often, when using absorbent components, expanded glass, expanded glass granules or expanded clay granules are used in order to achieve the best possible noise suppression.

In the DE 197 28 525 C1 For example, a process for the production of hydrothermally hardened cellular concrete and molded articles made of cellular concrete is described. The solid components of the aerated concrete are composed mainly of cement, lime, hard coal fly ash and a pore-forming agent. The use of fly ash for the production of aluminosilicate binders, which also include a cement kiln dust fraction and a predetermined amount of blast furnace slag, is known from e.g. EP 1 091 914 B1 known.

Especially reduced when using the known components as a plate-shaped body their absorption capacity clear. Partially can the current requirements for sound absorption no more or only with the use of particularly thick absorption plates Fulfills become.

task Therefore, it is the object of the present invention to provide a shaped body, in particular a mold plate, available to provide, the absorption capacity is significantly improved.

Is solved the present task by a shaped body, in particular a mold plate, with the features of claim 1 and by a method for Production of moldings with the features of claim 9. The back related claims have each preferred embodiments of the molding or the manufacturing process on.

The molding according to the invention is based on a mixture with the components cement, fly ash, aluminum oxide (Al ₂ O ₃ ). The shaped article is produced by mixing this dry mixture with water. Preferably, the dry mixture has the additional constituents iron oxide (Fe ₂ O ₃ ) and / or anhydrite.

According to the invention Composition of the components of the dry mixture such that 20 Weight percent (wt%) to 40 wt% cement. The amount Fly ash is between 40% by weight and 70% by weight. Alumina lies at a level of from 5% to 15% by weight. The optional component Iron oxide accounts for up to 5% by weight. The optional component Anhydrite has a proportion of up to 5% by weight. A shaped body with These components are known in the art as hydrosilicate molded body (or. Hydrosilicate plate) and is a conglomerate of hydrogranates and Hydro silicates.

Of the Shaped body according to the invention has a lot positive properties in terms of its absorption capacity. He is not just for the airborne sound insulation suitable but also has very good (air) sound absorbing properties. Therefore, it is particularly suitable for use in the form of a mold plate for Sound reduction to be used. The airborne sound is through the mold plate according to the invention not only muted, but also absorbed. The hydrosilicate plate with the above Composition also has a very high resistance to aging, so they over themselves a period of several ten years has not changed.

In a particular embodiment is the proportion of cement in the molding in the range of 25% by weight to 35% by weight, preferably from 28% to 30% by weight. Especially preferred the proportion of cement is 29% by weight for such a plate.

Also preferred is an absorption plate whose proportion of fly ash in the range of 45% by weight to 65% by weight, preferably between 50% by weight and 55% by weight. Very much preferred is a content of 53.5% by weight of fly ash.

In a further preferred embodiment of the molding, the proportion of aluminum oxide (Al ₂ O ₃ ) is in the range from 8% by weight to 13% by weight, preferably from 10 to 12% by weight. Particularly preferred are 11% by weight Al ₂ O ₃ .

Likewise preferred is a molded article whose iron oxide content (Fe ₂ O ₃ ) is in the range from 1.5% by weight to 5% by weight, preferably from 2% by weight to 4% by weight. The proportion is particularly preferably 3.5% by weight.

The proportion of anhydrite in the overall composition of the molded article is preferably between 1.5% by weight and 5% by weight, preferably between 2% by weight and 4% by weight. The proportion of anhydrite is particularly preferably 3% by weight.

Especially preferred is an embodiment of the molding or the mold plate with the composition of 29% by weight of cement, 53.5 wt% fly ash, 11 wt% wt%, 3.5 wt% iron oxide and 3 wt% Anhydrite. Such a mold plate has very good properties in terms of absorbency of sound and is very resistant to aging.

When Fly ash is doing this in thermal power plants while solid, disperse (particulate, particulate or dusty) residue. The particle size of the fly ash is between about 1 micron and 1 millimeter. Is preferred doing high quality fly ash, as known in the building materials industry is and is used.

In an embodiment has the shaped body inner capillary channels which are formed from individual isotropic capillaries. These preferably pull long-chain capillaries or capillary channels the entire shaped body. Under capillary channels are preferably arbitrarily shaped, elongated recesses understood, preferably from a plurality of cavities through their connection be formed. Preferably, the capillary channels are open towards the outside and (inside) connected to each other. Such a shaped body made of cellular concrete has a lot inside because of its isotropic capillaries good absorption properties. Airborne sound impinging on the molding gets into the capillary channels initiated and recorded by them. A reflection of the airborne sound on the surface of the molding is thus significantly reduced. The largest part of the sound occurs in the moldings and is quasi absorbed. Again emerging from the molding Sound is very much reduced and runs quasi in the connected capillary dead. An escape of the sound or even a reflection of the sound The plate is diffused, so that the impression a sound reduction or insulation he follows. The sound absorption coefficient α of the shaped body lies in the frequency range from 600 hertz greater than 60%, in the range between 800 and 1050 Hertz greater 80% percent.

in the Within the scope of the invention, it has been found that the molding is not has only very good sound-absorbing properties. Due to the Isotropic capillaries in the cellular concrete is also the shaped body suitable for humidification and / or dehumidification. The capillary channels can have a size Absorb amount of moisture and give it back slowly and slowly to the environment. The water absorption capacity of the molding according to the invention is at about 600 liters per cubic meter. By the moisture absorption and the storage of moisture, for example, the plate for Humidification and dehumidification of rooms be used. The molded body thus creates a very pleasant room climate. Possible areas of application of the material are therefore also the mold control.

in the Within the scope of the invention, it has been found that in the case of a shaped body with about 6.5 kilograms mass of moisture content in the dry state at 0.9 Volume percent is. After storage at 23 degrees Celsius room temperature and 80 percent relative humidity to mass constancy results in a mean equilibrium moisture content of 1.7 percent by volume.

in the Framework of the invention was about In addition, it has been found that the shaped bodies are also suitable for hydroponics, since they have a very high water absorption capacity.

Of the has shaped body according to the invention about that In addition the advantage that he has very good environmental compatibility having. In particular, he is for Allergic people very well suited because no allergy-producing substances be used. The molded body is therefore particularly suitable for use in home construction for sound insulation or for dehumidifying basements.

Of the moldings let yourself Simply recycle it after use as it contains no pollutants. In its Composition, it already corresponds to the cycle of economic and waste law, so that the moldings easy the recycling cycle supplied can be.

by virtue of the aforementioned properties of the fiber-free hydrosilicate plate is their field of application diverse. For example, it is possible Shaped body in Area of the road, Railway and aviation use; they are great as Noise barriers.

Furthermore can they as wall coverings for the salt protection can be used. Other applications are in the field of acoustic walls or acoustic ceilings. As broadband absorbers, they can be slotted with, perforated or raised surface structures be equipped to over to absorb a wide frequency range sound. Because of your Material properties, they are also suitable to be used in exhaust mufflers (for example as a core material).

In a preferred embodiment of the molded article, its density is between 100 and 400 Kilograms per cubic meter, preferably between 200 and 300 kilograms per cubic meter. In a particularly preferred embodiment, the density is 230 to 270 kilograms per cubic meter. Its compressive strength is approximately in the range of 1.0 to 1.5 Newton per square millimeter (N / mm ² ), the bending strength is in the range of 0.5 to 1 N / mm ² .

at The use as a building material is to be noted that the molding is not is flammable and thus categorized into class A1.

One Another advantage of the molding according to the invention is that in particular The absorption panels are very easy to work. The plates can Depending on the application, glued, screwed or poured. For example, you can they because of their inherent stability be clamped between two brackets, in particular when used as noise barriers be used.

to solution The above object is a method according to the invention for the production of moldings proposed. In particular, moldings according to the invention or Produce mold plates. The production of the shaped body takes place in several steps. The components are cement, fly ash and alumina mixed in a mixer. The mixture is batchwise. Especially ferric oxide and / or anhydrite are preferably added as further components given. The exact composition of each component depends on the properties of the molding but defined within the scope of the above-mentioned composition, the proportion of fly ash dominates. Of course, more can Components should be included.

In front or while Mixing the dry components is added to the mixture of water. Prefers the proportion of water is about 2/3 of the mass of the mixture from the dry individual components. Before granted the share of water between 50 and 75 percent by weight to the sum of the individual Components.

in the further process step, a foaming agent is added. This is preferably carried out in a (horizontal) agitator, preferably a Includes screw mixer with a worm wheel.

Of the Foaming agent is preferably a sugar-based synthetic product, which is added slowly. The foaming agent thus comprises glucose derivatives and is preferably hydrophobic. For example, the foaming agent can based on an oleic acid and partly has a protein base, ie includes proteins. The dosage of the foaming agent takes place in dependence of the desired volume weight. The use of a foaming agent makes the formation of individual promoted and supported (gas or) air-containing cells (pores).

Either the component water as well as the foaming agent are used as long added until a desired one Volume is reached. Once a homogeneous mixing and the desired Volume is present, the mixture is poured into a mold and subsequently at a predefined preheating temperature tempered until the mixture forms a dimensionally stable blank. In a further step, the blank is removed from the mold and a heat treatment at a predetermined process temperature and a predetermined one Process pressure over a defined time exposed to form a molding. The finished molding can then continue are processed.

By the inventive method Is it possible, from the above components to form shaped bodies, the large-celled Have capillaries in open cells. The resulting during manufacture Isotropic capillaries in a cellular concrete form the basis for the very good absorption properties, which allow both to absorb sound as well as big ones Take in amounts of moisture and slowly bring them back to their Environment.

According to the invention open-cell structure of the finished material formed by that the manufacturing process takes place in several stages. After the formation of the mixture and filling in a form is preferred in a first process stage by the Use of ferrite-containing raw materials a stable chain of hydrogranates educated. In this process stage, which takes place before tempering is the stuffed in a mold Mixture for at least 30 minutes, preferably at least 45 minutes and especially preferably at least 60 minutes at a predetermined temperature stored. Very preferred is an intermediate storage of at least 90 minutes. Storage at temperatures between 20 to 40 degrees Celsius can be stored in a special heat chamber or in a warehouse occur. In special cases Interim storage should not take more than 90 minutes. In terms of an economic Process flow is the storage temperature depending on the composition of the Components to choose and to optimize.

In a second stage after storage, the mixture filled in molds is tempered. Preferably, the tempering takes place in a heat chamber whose temperature is about 10 to 50 degrees Celsius warmer than the introduced into the heat chamber mixture. Preferably, the temperature of the Warming chamber 10 to 30 degrees Celsius warmer than the mixture in the mold, which is also referred to as green body. The tempering process preferably takes place at an atmospheric humidity of 50 to 80 percent, which is preferably kept constant by regulation of the heating chamber.

The Process stage of the tempering takes at least 12 hours, preferably at least 24 hours and most preferably at least 36 hours. In a particularly preferred embodiment of the Procedure is the mixture for at least 48 hours in the warming room brought in. Inside the heat chamber form during the tempering process in the mixture further hydro grenade, the harder become. By hardening of the cement (for example in the form of tobermorite) increase the cells in the mixture by about 7 to 25 volume percent. By the warming increases the enclosed in the individual cells (pores) air, the trying to evaporate. The individual cell walls are broken up; it capillaries form. In this process step, so the air in the big one Heated number of existing pores, which expands and connects and opens the cells. This will an extreme capillary structure with preferably long-chain capillaries educated. At the same time, while the process stage of tempering the actual mass of the mixture in a natural Strength process solidified. From the mixture is a dimensionally stable Blank.

In a preferred third stage of the manufacturing method according to the invention the blank is subjected to a heat treatment undergone in an autoclave (hardening kettle). The heat treatment is preferably carried out at a pressure of about 8 to 20 bar. Especially Preferably, the pressure is between 10 and 14 bar. By the pressure in the autoclave, the breakup of the individual cells is promoted, so that the crosslinking of the cells to a capillary structure and to several cavities supports becomes. The individual cavities are while gas-containing, preferably containing air.

In a preferred embodiment This third stage of the manufacturing process can be two sections include, in each case a temperature change with different rates of change can be provided.

In front the heat treatment of the blank and after tempering, the blanks of the forms, the for the manufacturing process of tempering were necessary, turned off. For the production of mold plates, the moldings are cut accordingly.

The molded article produced by the production process according to the invention or the molding plate is distinguished by the fact that a solid solution is formed between four different compounds which, for example, are preferably hydrogranates. A fixed position solution is a grid structure in which the individual components always have the same position and neighborhood. The four compounds of the fixed solution are:
C ₃ FH ₆
C ₃ FS ₃ (Andradite)
C ₃ AH ₆
C ₃ AF ₃ (Grossular, Grosulartrit)

Here, the placeholder C stands for calcium (Ca), A for aluminum ₂ (Al ₂ ), H for water (H ₂ O), F for iron ₂ (Fe ₂ ) and S for a silicon oxide (Si ₃ O ₄ ). For example, for Andradit the formula: Ca ₃ Fe ₂ Si ₃ O ₁₂ results, for Grosulartrit (CA ₃ Al ₂ Si ₃ O ₁₂ ).

The Invention will be described below with reference to those in the figures preferred embodiments explained in more detail. The Particularities shown therein may be individual or in combination used to further preferred embodiments of the invention to accomplish. The described embodiments do not provide restriction the generality of the subject matter defined in the claims or method dar. It show:

1 a schematic diagram of the method according to the invention; and

2 additional optional process steps.

1 shows the process flow of the manufacturing method according to the invention. In one with 1 designated filling station, the components of cement, fly ash, alumina, iron oxide and anhydrite in a container 2 filled. About a pipeline 3 Water is added to the ingredients. In the container 2 is a stirrer 4 arranged, by means of which a matrix mixture of the components and water is produced. The mixture is placed in a vertical mixer 5 with a vertical worm wheel 6 filled from formed stirrer, which is operated by a motor. A foaming agent is via a foam gun 7 the vertical mixer 5 fed. The mixture is mixed in the vertical mixer until the volume of the mixture has reached a certain, predetermined volume. The foaming agent and water can be replenished as needed to increase the volume.

In a filling station 8th the mixture is filled into individual molds that are stored in a storage station 9 be stored. The storage takes place at temperatures between 20 and 40 degrees Celsius for preferably 45 to 90 minutes. From the storage station 9 become the filled molds with the mixture in a preheat chamber 10 in which the mixture is stored for at least 12 hours. The preheat chamber can be heated and operated with a predetermined humidity, which is between 50 and 95 degrees of humidity, more preferably 80 degrees does not exceed atmospheric humidity. The air within the preheat chamber is recirculated to provide constant temperature and humidity conditions.

In the preheating chamber, during the preheating process (tempering), the volume within the cells of the mixture increases by 7 to 25 volume percent. At the end of the tempering process, a dimensionally stable blank has emerged from the mixture, which is in a stripping station 11 is turned off from the molds. The blanks are placed in an intermediate processing station 12 processed in an intermediate processing step, for example, a block-like molded body is cut into sheets of desired thickness and size. Preferably, the plates have a thickness of 20 to 40 millimeters.

Subsequently, the plates are stored at a distance on a rack or stacked on top of each other. The usually mobile frame is in an autoclave together with the spaced plates in a next processing step 13 introduced, in which a heat treatment of the processed blank takes place. The individual plates are exposed at a pressure of 10 to 14 bar a temperature between 140 and 200 degrees Celsius (° C). The hydrothermal heat treatment in the autoclave preferably takes place in two process sections:
In the first process section, the temperature (preferably starting from room temperature) is increased by about 20 ° C. per hour until a temperature of about 140 ° C. is reached. During this phase of the temperature rise further hydrogrencates and capillaries are formed in the blank. Individual cells literally burst and connect with each other to form long-chained channels.

In a second section of the heat treatment becomes a temperature increase with a temperature change between 23 ° C per hour and 30 ° C per hour, preferably with a temperature change of 25 ° C per hour instead of. The temperature is increased until a final temperature of at least 170 ° C, preferably at least 180 ° C and more preferably at least 190 ° C is achieved. Preferably lies the final temperature below 200 ° C, preferably below 195 ° C.

in the first process section is preferably a final temperature (intermediate end temperature) of at least 120 ° C and at most 150 ° C, preferred at the most 140 ° C reached.

To the second process section of the heat treatment has the material his desired Strength achieved and can be used.

2 shows further optional manufacturing steps or stations: In a further step is in a drying station 14 The shaped body is dried before being stored 17 is stored for delivery.

Optionally, the molding after drying in the drying station 14 in a kiln 15 at a temperature between 1000 ° C and 1400 ° C for a predetermined time, preferably several hours, fired. Due to the firing process, a ceramic product can be formed from the shaped body.

Another process step may be a finishing station 16 include, in which the individual moldings or mold plates are aftertreated. This may include, for example, aging as well as finishing or special treatment such as coating or grinding or the like. Also, the moldings present as blocks can be shrunk. In the finishing station 16 or in the storage station 17 The mold plates are provided with special brackets so that they can be installed on site without unnecessary assembly steps.

Claims (18)

Moldings, prepared from a water-reacted dry mix which 20-40 % By weight of cement, 40-70 % By weight fly ash and 5-15 Wt% alumina. moldings according to claim 1, characterized in that the dry mix in addition to to 5% by weight of iron oxide and / or up to 5% by weight of anhydrite. moldings according to claim 1 or 2, characterized in that the proportion of cement in the range of 25% to 35% by weight, preferably 28% by weight is up to 30% by weight, very preferably 29% by weight, and / or the proportion of fly ash in the range from 45% to 65% by weight, preferably from 50% to 55% by weight, very preferably 53.5% by weight. Shaped body according to one of the preceding claims 1 to 3, characterized in that the proportion of aluminum oxide in the range of 8 wt% to 13 wt%, preferably from 10 wt% to 12 % By weight, more preferably 11% by weight. moldings according to claim 2, characterized in that the proportion of iron oxide in the range from 1.5% to 5% by weight, preferably from 2% to 4% by weight is particularly preferably 3.5% by weight, and / or the proportion of Anhydrite in the range of 1.5% to 5% by weight, preferably 2% by weight to 4% by weight, more preferably 3% by weight. moldings according to one of the preceding claims, characterized that he has inner capillary channels having. moldings according to one of the preceding claims, characterized that its density is between 100 and 400 kilograms per cubic meter, preferably from 200 to 300 kilograms per cubic meter and especially preferably between 230 and 270 kilograms per cubic meter. Shaped body according to one of the preceding claims, characterized in that it has a lattice structure in which the compounds Ca ₃ Fe ₂ (H ₂ O) ₆ Ca ₃ Fe ₂ (Si ₃ O ₄ ) ₃ Ca ₃ Al ₂ (H ₂ O) ₆ Ca ₃ Al ₂ (Fe ₂ ) ₃ always have the same position and neighborhood. Process for the production of moldings with the following steps: - mixing a dry mixture containing at least the components cement, alumina and flyash in a mixer to form a mixture; - Add by Water before or during of mixing; - Add one Foaming agent to the mixture; - pour the mixture into one Shape; - tempering of the mold filled Mixture at a predefined preheat temperature until the mixture forms a dimensionally stable blank; - Remove the blank the form; - hydrothermal heat treatment of the blank to process by means of process temperature and process pressure in one Process time to form a molding. Method according to claim 9, characterized by the next step: Adding iron oxide and / or Anhydrite. Method according to claim 9 or 10, characterized that the drying out of the heat-treated Moldings for at least 24 hours. Method according to one of claims 9 to 11, characterized that, the dried moldings with a firing temperature between 900 and 1400 degrees Celsius are fired to ceramic moldings. Method according to one of claims 9 to 12, characterized that the mixture of components in an agitator with a foaming agent is mixed, with the agitator preferred comprises a screw mixer with a worm wheel. Method according to one of claims 9 to 13, characterized that the tempering takes place with a preheating temperature in a heating chamber, their temperature is 10-30 Degrees Celsius warmer is as the temperature of the introduced form and / or where the preheat at least 12 hours, preferably at least 24 hours, very preferred at least 36 or more preferably at least 48 hours. Method according to one of the preceding claims 9 to 14, characterized in that before the tempering with a preheating the filled into a mold Mixture for at least 30 minutes, preferably at least 45 minutes, especially preferably at least 60 minutes, and most preferably at least 90 Stored at a temperature between 20 and 40 degrees Celsius becomes. Method according to one of claims 9 to 15, characterized that the heat treatment the blank in an autoclave at a pressure of 8-20 bar, is preferably carried out at a pressure of 10-14 bar. Method according to claim 16, characterized in that that the heat treatment of the blank comprises a first process phase in which a temperature increase from 20 degrees Celsius per hour to a final temperature of at least 120 degrees and at most 150 degrees Celsius, preferably at most 140 degrees Celsius, performed becomes. Method according to claim 17, characterized in that that the heat treatment of the blank comprises a second process phase in which the temperature by 25 degrees Celsius per hour to at least 170 degrees Celsius, preferred at least 180 degrees, more preferably at least 190 degrees Celsius, elevated becomes.