DE10011757A1 - Molded body has a water-containing component as hardener and an inorganic rock-like component containing thermally activated clay - Google Patents

Abstract

Molded body has an inorganic rock-like component and a water-containing component as hardener effecting a hardening reaction of the rock-like component in the alkali region. The rock-like component contains clay thermally activated at 450-950 [deg] C.

Description

Technical area

The invention relates to a molding compound or the compilation of the components consisting of several parts - for the manufacture of an inorganic molded body according to the preamble of claim 1, a method for producing an inorganic molded body and an inorganic molded body produced by this method. From generic molding compositions containing an inorganic stone-forming component and a water-containing second component as a hardener, which causes a hardening reaction of the stone-forming component in the alkaline range, compact moldings with a density of about 1,600 kg / m ³ and foamed products with densities of about 150 kg / m ³ to 800 kg / m ³ .

State of the art

Generic molding compounds and various areas of application for this are z. B. from EP 0 100 848 B, EP 0 148 280 B, DE 32 46 602 A, DE 32 46 619 C, DE 32 46 621 C, DE 33 03 409 C, EP 0 199 941 B, DE 35 12 516 C, EP 0 254 165 B, EP 0 374 195 B, EP 0 417 582 B, EP 0 417 583 B, DE 40 25 212 C, EP 0 561 978 B, EP 0 599 895 B and WO 93 21 126 A are known.

The following are particularly known as reactive solids that form the so-called stone-forming component:

• 1. finely divided, at least partially amorphous aluminosilicate with contents of amorphous silicon dioxide and aluminum moxide,
• 2. vitreous, amorphous electrostatic precipitator ash,
• 3. ground calcined bauxite,
• 4. electrostatic precipitator ash from lignite power plants,
• 5. Undissolved, amorphous SiO ₂ , in particular from an amorphous, disperse-powdery, dehydrated or water-containing silica or from high-temperature processes (Silica Fu me),
• 6. Metakaolin

The reactive solids mentioned under-react easier self-heating with alkali silicate solutions, whereby the Formation of solid moldings within 20-120 minutes is triggered. The reaction that takes place is also called Geopolymerization and the moldings formed in the process as Called geopolymers. Depending on the reactivity of the stone-forming Component must be the molding compound to start the reaction to a Can be heated to a temperature of 40-80 ° C.

_{An alkali silicate solution (water glass solution) with 1.2 to 2.5 mol SiO 2} per mole K ₂ O and / or Na ₂ O is known as a hardener that causes a hardening reaction of the stone-forming component in the alkaline range.

As far as light foamed moldings are to be Herge from the molding compositions, these can be used as foaming agents z. B. 10 wt .-% - contain _{H 2} O _2.

As fillers in the foamable and curable inorganic c masses are in particular mica and fine-grained valley used cumulatively.

The reactive known from the documents mentioned above Components have e.g. Sometimes only a small amount or depending on the batch strongly changing reactivity, e.g. Sometimes they are relatively expensive.

task

The object of the invention is therefore to provide a generic form mass, a molded body formed therefrom and a method its manufacture on the basis of an alternative stone-forming Component available.

Presentation of the invention

The invention solves this problem by means of a molding compound according to An Claim 1, preferably in conjunction with one or more of the Features of the subclaims, as well as by a method according to An claim 7 or by a molded body according to claim 9.

"Composition" in the context of the invention is the sum the not yet (completely) mixed components of the mold mass understood.

The core of the present invention is the use of clay, the was thermally treated in a certain temperature range de, as a reactive stone-forming component. This realization is surprising as far as it is known that normal sound that has not been treated in this temperature range Shows reactivity with an alkali silicate solution. Likewise with ground fired clay, such as B. brick flour, so at Tem Temperatures above 950 ° C fired and then ground Clay, not reactive with the hardener used according to the invention.

It is preferred as a starting point for reactive stone-forming Component a commercially available dried and ground clay used for a period of 30-120 min of a Tempe temperature above 450 ° C and below 950 ° C. Through this Temperature treatment obviously becomes a structural ver change in the clay components that subsequently lead to the the desired reactivity with the hardener. So much for the tone If it was not ground before thermal activation, it must possibly still be ground after the thermal treatment. the Average grain size should not exceed 50 μm, preferably not more than 15 μm and particularly preferably not more than 5 μm gene.

The temperature treatment (activation) is preferred for a Temperature of 480 ° C-800 ° C, particularly preferably between 500 ° C and 650 ° C and in particular below 600 ° C carried out. at an increase in the activation temperature to values above 500 ° C the reactivity of the activated clay no longer increases significantly lich on, while the treatment of the clay at higher tempera tures is associated with higher energy consumption. Exceeds the treatment temperature has a critical value of approx. 900 ° C, the sound is no longer responsive.

In addition to the clay activated as described, the stone-forming component can also contain other reactive components, in particular the already known reactive solids from the group consisting of

• 1. finely divided, at least partially amorphous aluminosilicate with contents of amorphous silicon dioxide and aluminum moxid, especially as electrostatic precipitator dust corundum production
• 2. vitreous, amorphous electrostatic precipitator ash,
• 3. ground calcined bauxite,
• 4. electrostatic precipitator ash from lignite power plants,
• 5. undissolved, amorphous SiO ₂ , in particular from an amorphous, disperse-powdery, dehydrated or water-containing silica or from high-temperature processes (silica fume) and
• 6. Metakaolin.

The reactivity of the activated clay and the compressive strength the molded body produced therefrom is approximately in the middle range rich in the above-mentioned reactive solids known per se or the molded body produced therefrom.

As a natural sediment, clay is available in almost unlimited quantities supply, so that the reactive solid obtained therefrom inexpensively is and light in large quantities with very uniform reaction vity can be established.

An alkali silicate solution with 1.2 to 2.5 moles of SiO ₂ per mole of K ₂ O or Na ₂ O is preferably used as the second component forming the hardener. In the alkali silicate solution, K ₂ O is preferred over Na ₂ O. The alkali silicate solutions should contain excess alkali. The pH value is preferably <13, the density between 1.2 and 1.7 kg / dm ³ . Such alkali silicate solutions are very preferably obtained by dissolving amorphous, disperse-powdery, water-containing silica, the so-called precipitated silica. A solution of the alkali metal hydroxide or solid alkali metal hydroxide with the addition of water is preferably reacted with the precipitated silica. Instead of the precipitated silica, amorphous SiO ₂ from high-temperature processes (silica fume) can also be used.

The molding composition according to the invention can optionally be further processed into compact moldings with a density of about 1.2 to 3 kg / dm ³ or into foamed open-pore or closed-pore moldings. In particular, hydrogen peroxide (H ₂ O ₂ ) or sodium perborate are used for foaming. When the molding compound is slightly heated, oxygen peroxide releases oxygen as a foaming agent; the heat release accelerates the setting reaction. By changing the amount of foaming agent used, molded bodies with densities of about 200 kg / m ³ to over 800 kg / m ^{3 can be} produced.

To improve the physical properties of the moldings Fillers can preferably be used per, in particular Talc, mica, cordierite chamotte and / or alkali-resistant inorganic fibers such as B. Zirconium Silicate Fibers.

A preferred field of application of the form according to the invention mass, in particular the invention containing a foaming agent molding compositions according to the invention, is the construction sector, in particular the Production of on the one hand viable and on the other hand good thermally insulating components and elements in the building rich. The combination with brick Construction elements, since the same thing for brick production material, namely clay, is used.

An advantageous application is the filling in of so-called th filling bricks with the foamable form according to the invention mass, and particularly preferably the molding material according to the Firing process in the cavities of the still 60 ° C to 110 ° C warm Filling brick is poured in, eliminating the residual heat of the brick to accelerate the foaming and setting reaction of the er inventive molding compound is used.

The invention is based on execution and Ver same examples and the drawing described in more detail.

Brief description of the drawing

It show thereby

Fig. 1 is a Füllziegel before filling with a molding composition OF INVENTION to the invention;

Fig. 2 shows a filler brick after filling with a foamed molding compound according to the invention.

Ways of Carrying Out the Invention and Comparative Examples example 1

For the preparation of the reactive component, han The usual dried and ground clay with a medium ren grain size (50 wt .-% value) of 0.51 µm in an oven for Exposed to a temperature of 480 ° C for 120 min. The single ones Clay particles had no tendency to agglomerate or to bake together.

Using this reactive component, a solid mixture of the following composition is homogenized in a high-performance batch mixer within 300 s:

Reactive component (clay treated at 480 ° C) 74% by weight talc 25 wt% Fibers 1% by weight

To produce a test foam body with a ^{volume of 1 dm 3,} 260 g of this solid mixture are added to 200 g of hardener and mixed thoroughly with a stirrer.

The liquid hardener is composed as follows:

SiO ₂ 26.0% by weight Na ₂ O 9.5% by weight

K ₂ O 13.5% by weight H ₂ O 51.0% by weight Density (20 ° C) 1.6 g / cm ³ _{SiO 2} / M ₂ O molar ratio 1.47: 1 (M = K or Na)

Then, with the agitator running, 13 ml of 10% by weight H 2 O _{2 are added to the mass.} The molding compound begins to foam up after about 10-20 s due to the decomposition of the hydrogen peroxide in a strongly alkaline environment. The mass is then exposed to a temperature of 60 ° C in a drying cabinet. The hardening reaction starts after approx. 20 minutes.

After the shaped body has hardened after about 50 minutes, it can can be taken out of the drying cabinet and removed from the mold. Final Finally, drying takes place for 6 hours at 90.degree.

After drying, the foamed molding was used for loading mood of physical properties a cube-shaped Test specimen manufactured with an edge length of 50 mm, whereby the surfaces carefully to increase reproducibility must be ground plane-parallel.

The physical properties were:

Density: 530 g / dm ³
Compressive strength (similar to DIN 52105): 2.8 N / mm ²

Example 2

To produce a compact, ie unfoamed, molded body, the reactive component was first produced as in Example 1 by heat treatment at 480.degree. A solid component was first mixed from 66.6% by weight of this reactive component and 33.3% by weight of ground cordierite chamotte as filler. 60% by weight of this solid mixture was mixed with 40% by weight of the hardener according to Example 1 and the molding composition was cured in a drying oven heated to 50 ° C. within 60 minutes. As a result of the exothermic reaction, the temperature in the middle of the sample rose to approx. 58 ° C. The cured compact molding had a compressive strength of 17.5 N / mm ² .

(Comparative) Examples 3 to 12

To determine the Tem ten tests were carried out as follows (comparative examples 3 to 7, Examples 8 to 11 and Comparative Example 12) with ver different activation temperatures of the clay carried out.

First, as in Example 1, the clay was exposed to an activation temperature given in Table 1 for 120 minutes in each case to produce the reactive component. With the solids produced in this way, a molding composition was produced as in Example 1 with the addition of talc and fibers and the hardener given in Example 1 and with the addition of the amount of H _{2 O given in Example 1 as a foaming agent.} The molding compositions according to Experiments 1 to 10 were each heated to a temperature of 60.degree. In experiments 1 to 5 (comparative examples 3 to 7) and in comparative example 12, there was no curing in each case. In tests 6 to 9 (examples 8 to 11), within the typical test scatter, there was approximately the same compressive strength of 2.4 to 2.9 N / mm ² .

Table 1

Example 13

To produce a thermally insulated component, a filler brick 1 ( FIG. 1) is first fired from clay at 1000 ° C. in a manner known per se. After firing, the filling brick 1 is initially cooled down to a temperature ϑ of 95 ° C.

Then a foamable molding compound 3 according to Example 1, but with the amount of H ₂ O ₂ increased to 20 ml, is poured into the cavities 2 , 2 ', the amount initially filling about 20% of the volume of the cavities. Due to the residual heat of the filling brick 1, the molding compound 3 foams up quickly and, after a short time, completely fills the cavities 2 , 2 '. Any remaining mass is sheared off. After about 45 minutes, the molding compound 3 has hardened. Finally, the residual water remaining in the hardened molding compound 3 is expelled in a drying oven.

Claims (10)

1. Molding compound or a set of components consisting of several parts for the production of an inorganic molding,

• - with an inorganic, stone-forming component and
• - As a hardener of a water-containing second component, which causes a hardening reaction of the stone-forming component in the alkaline range,

characterized in that the stone-forming component contains a thermally activated clay at a temperature between 450 ° C and 950 ° C. 2. Molding compound or composed of several parts position of the components according to claim 1, characterized records that the clay at a temperature of 470 ° C to 950 ° C, preferably between 480 ° C and 700 ° C, especially be was preferably treated up to 650 ° C and a medium grain size <50 µm, preferably <5 µm. 3. Molding compound or composed of several parts together position of the components according to one of claims 1 or 2, characterized in that it additionally contains H ₂ O ₂ or Na trium perborate as a foaming agent. 4. Molding compound or composed of several parts together position of the components according to one of claims 1 to 3, characterized in that an alkali silicate solution with 1.2-2.5 moles of SiO ₂ per mole of K ₂ O as the water-containing second Kom component (hardener) and / or Na ₂ O, a density of 1.2 to 1.7 kg / dm ³ and a pH value <13 is used. 5. Molding compound or composed of several parts together position of the components according to one of claims 1 to 4, characterized in that the stone-forming component additionally has one or more solids reactive with the hardener from the group consisting of

• 1. finely divided, at least partially amorphous Alumosi likat with contents of amorphous silicon dioxide and aluminum oxide, in particular as electrostatic precipitator dust from the production of electrical corundum
• 2. vitreous, amorphous electrostatic precipitator ash,
• 3. ground calcined bauxite,
• 4. electrostatic precipitator ash from lignite power plants,
• 5. undissolved, amorphous SiO ₂ , in particular from an amorphous, disperse-powdery, dehydrated or water-containing silica or from high-temperature processes (silica fume),
• 6. Metakaolin

contains. 6. Molding compound or composed of several parts together position of the components according to one of claims 1 to 5, characterized in that they also contain one or more solids from the group consisting of as a filler

• 1. Talc
• 2. Mica
• 3. Cordierite chamot
• 4. Alkali-resistant inorganic fibers

contains. 7. Process for the production of an inorganic shaped body, characterized by the use

• - A clay thermally activated at a temperature between 450 ° C and 950 ° C as a stone-forming component
• - and an alkali silicate solution with 1.2-2.5 mol SiO ₂ per mol K ₂ O and / or Na ₂ O, a water content of 45-75% by weight and a pH value <13 as hardener.

8. The method according to claim 7, marked by the use of H ₂ O ₂ or sodium perborate as a foaming agent. 9. Moldings made using

• - an inorganic, stone-forming component and
• - As a hardener of a water-containing second component, which causes a hardening reaction of the stone-forming component in the alkaline range,

characterized in that the stone-forming component contains a thermally activated clay at a temperature between 450 ° C and 950 ° C. 10. Use of a molding compound according to claim 3, characterized ge indicates that the molding compound is in the cavities of bricks products and using the residual heat is cured by the firing process.