Composition for producing components

Abstract

The invention relates to a composition for producing components, the composition containing solid constituents which comprise at least one base material and meta-clay, and containing an activation solution, wherein the activation solution comprises more than 5% by mass alkali silicates, the mass of the base material is 200% to 500% of the mass of the meta-clay and the ratio between the mass of the activation solution and the mass of the meta-clay is greater than 1.The invention further relates to a method for producing a component, in which, in a first step, a mixture of a composition that comprises solid constituents with at least one base material and meta-clay, and an activation solution is produced, characterized in that the activation solution comprises more than 5% by mass alkali silicates, the mass of the base material is 200% to 500% of the mass of the meta-clay and the ratio between the mass of the activation solution and the mass of the meta-clay is greater than 1, and, in a second step, the mixture is formed to a component by means of an extruder.

Description

[0001] Composition for the production of components

[0002] The invention relates to a composition for producing components, comprising solid components which have at least one base material and meta-clay, as well as an activation solution.

[0003] A variety of compositions and processes are known from the state of the art for producing building components such as bricks or walls. Bricks can, for example, be hewn directly from rock or formed and fired as clay or adobe bricks to achieve sufficient strength for constructing walls.

[0004] One known method for producing components is to produce a geopolymer composition and then extrude it to form a component. A special composition and a method for producing a geopolymer component are described in EP 2727894 B1. In this method, meta-clay, clay and an activating solution are first mixed together, the resulting composition is then extruded and the shaped component is finally dried. In the composition used, clay is added which has a mass of 5% to 40% by mass of the mass of the meta-clay. The ratio between the activating solution and the solid components, in particular the meta-clay and the clay, is between 0.25 and 0.85. The activating solution also contains sodium or potassium silicate in a proportion of between 0 and 20% by mass.This process can produce components with a strength of up to approximately 30 MPa.

[0005] A disadvantage of the known processes and compositions for the production of geopolymer components is their low strength, which is significantly lower than the strength that can be achieved, for example, with conventional fired bricks.

[0006] It is therefore an object of the invention to provide a composition which enables a higher strength of the finished component.

[0007] According to the invention, in a composition of the type mentioned at the outset, the activation solution contains more than 5% by mass of alkali silicates, the mass of the base material is 200% to 500% of the mass of the meta-clay and the ratio between the mass of the activation solution and the mass of the meta-clay is greater than 1.

[0008] According to the invention, the solid components therefore comprise meta-clay. Furthermore, the solid components comprise a base material which preferably consists either (only) of clay, (only) of sand, or clay and sand. The mass of the clay and / or the sand is furthermore 200% to 500% of the mass of the meta-clay. If the base material only comprises clay and no sand, the mass of the clay is 200% to 500% of the mass of the meta-clay. If the base material only comprises sand and no clay, the mass of the sand is 200% to 500% of the mass of the meta-clay. It is preferably provided that the base material comprises clay and sand or consists of clay and sand. It is particularly preferred that the ratio between the mass of clay and the mass of sand is between 0.2:1 and 4:1, preferably between 0.5:1 and 2:1, particularly preferably between 0.8:1 and 1.2:1, in particular approximately 1:1.

[0009] The composition can be mixed to form a substantially homogeneous mass, which is subsequently used to mold a component. The mass provided by the composition is also preferably kneadable to ensure good formability. The composition preferably contains no further components besides the explicitly listed components, in particular the base material, the meta clay, and the activation solution, except for minor impurities.

[0010] Clay (or clay minerals) comprises phyllosilicates, which have a layered crystal structure composed of silicon and oxygen, as well as hydrogen, and usually magnesium and aluminum. The silicate anions consist of layers of corner-sharing SiCh tetrahedra. These include, for example, mica, chlorite, smectite, and kaolin. The clay can be dried or moist before being mixed with the other components. Preferably, the clay is not thermally treated before being mixed with the other components of the composition according to the invention.

[0011] For the purposes of this invention, meta-clay refers to clay that has been treated at high temperatures (approximately 500°C to 900°C) to remove bound water and alter the structure or crystal lattice. Meta-clay consists predominantly of reactive silicon dioxide and aluminum oxide. A well-known example of this is meta-kaolin, which is kaolin treated at approximately 550°C to 850°C.

[0012] By mixing the composition according to the invention, a geopolymer is formed due to a chemical reaction between the solid components, in particular the meta-clay, and the activation solution. The geopolymer according to the invention has the property of exhibiting high compressive strength, for example, approximately 60 MPa (N / mm), after a curing period (approximately 14 days) following the molding of a component. 2). Furthermore, it is not necessary to actively apply heat or pressure during curing. Curing can therefore take place in ambient air. Preferably, curing takes place at an air temperature of at least 20°C and at least 50% relative humidity (rH). Curing is particularly preferably carried out at an air temperature of 20°C-30°C and a relative humidity of 50% to 90%, preferably 50% to 80%.

[0013] It is preferably provided that the base material comprises sand, preferably quartz sand, wherein the mass of the sand is preferably 10% to 500%, particularly preferably 100% to 300% of the mass of the meta-clay. This further increases the strength of the composition in the dried-out state. The solid components, in particular the clay and the meta-clay and optionally the sand, are preferably in powder form when mixed with the activating solution. The sand can be dry or moist before being mixed with the other components. The sand, in particular the quartz sand, preferably has a grain size of 0.05 to 0.5 mm, particularly preferably 0.1 to 0.2 mm.

[0014] The moisture content of the individual components, in particular clay and / or sand, can be determined before or during the preparation of the composition and the recipe of the composition can be adjusted if necessary, for example by adding more or less water to the activation solution.

[0015] The base material may also be or comprise one or more of the following materials:

[0016] ■ Wood (materials), such as o Veneer strips o Veneer residues o Wood shavings (preferably 100 to 200 mm long, 10 to 50 mm wide and 0.6 to 1.5 mm thick) o Wood chips (preferably 0.5 to 3 cm long) o Wood chips, wood chips, wood veneer

[0017] ■ Plastic (residues), such as o Finely ground plastic powder (preferably with grain sizes of 0.15 to 0.50 mm) o Plastic granulate, ground or extruded (preferably with grain sizes of 1 to 5 mm) o Chopped plastic shreds

[0018] ■ Recycled materials, such as o from plastics o from building materials, ceramics, road surfaces and / or metals o from mineral construction waste (preferably ground to grain sizes of 0.1 to 50 mm)

[0019] ■ Mineral lightweight fillers, such as o Glass beads o Polystyrene, e.g. expanded polystyrene EPS ("Styrofoam") or extruded polystyrene XPS o PU foam (leftovers) o Fillers for lightweight materials such as foam, expanded clay, expanded glass, expanded slate, foam glass, perlite, vermiculite, cellulose fibers or flakes, expanded plastics

[0020] ■ Glass (remains), such as o broken glass o optical functional elements such as glass spheres as

[0021] reflectors

[0022] ■ Fibres, such as mineral wool, glass fibres, carbon fibres, wood wool, plant fibres, straw, hair

[0023] ■ Waste from the food industry (preferably difficult to compost), such as kernels and shells

[0024] The activating solution is preferably a liquid. This allows for easy mixing with the solid components of the composition.

[0025] In addition to the alkali silicates, the activation solution preferably comprises a hydroxide, particularly preferably potassium hydroxide and / or sodium hydroxide, and / or rubidium hydroxide and / or cesium hydroxide.

[0026] Furthermore, it is preferably provided that the alkali silicates are sodium silicates and / or potassium silicates. Alternatively or additionally, the alkali silicates can also comprise lithium silicates. The use of sodium silicates, potassium silicates, and / or lithium silicates (water glass) in liquid form enables simple alkaline activation of the solid components of the composition according to the invention. Although lithium water glass has the best reactivity, it is more expensive than sodium water glass and potassium water glass.

[0027] It is preferably provided that the activation solution comprises potassium hydroxide and potassium silicate. An activation solution comprising potassium hydroxide and potassium silicate preferably contains no further hydroxide and no further silicate. Furthermore, it is preferably provided that the activation solution comprises sodium hydroxide and sodium silicate. An activation solution comprising sodium hydroxide and sodium silicate preferably contains no further hydroxide and no further silicate.

[0028] Preferably, the activation solution contains between 20% and 90% by mass, particularly preferably between 40% and 80%, and especially approximately 50% to 70% by mass of alkali silicates. In these ranges, the achievable strength of the final product, i.e., a component, is at its highest.

[0029] Furthermore, it is preferably provided that the base material comprises clay, wherein the mass fraction of the clay is preferably 200% to 400%, particularly preferably 250% to 350%, of the mass fraction of the meta-clay. With this ratio between clay and meta-clay, there is a favorable ratio between reactive material and fillers in order to be able to produce a stable component. In order to further increase the strength of the component formed, it is preferably provided that the ratio between the mass of the activating solution and the mass of the meta-clay is between 1.1 and 1.6, particularly preferably between 1.25 and 1.35. In addition, this ratio has a positive effect on the flowability of the composition and thus the ease of processing the composition.

[0030] Furthermore, it is preferably provided that the ratio between the mass of the activation solution and the mass of the solid components is between 0.2 and 0.4, particularly preferably between 0.25 and 0.35. With this ratio, good kneadability of the composition can be achieved, which improves its processability into a component.

[0031] In a preferred embodiment, the meta-clay comprises meta-kaolin. It is particularly preferred that the meta-clay be meta-kaolin. Meta-kaolin is proven and well-suited for use in geopolymers.

[0032] The activation solution preferably contains water (H2O). This serves to improve miscibility and bonding of the individual components of the composition during mixing.

[0033] The composition preferably comprises, based on the total mass of the composition, 50% to 70% by mass of base material, 5% to 20% by mass of meta clay, 5% to 20% by mass of alkali silicates, 0% to 10% by mass of hydroxide and 0% to 25% by mass of water. The invention further relates to a process for producing a component, in which in a first step a mixture of a composition comprising solid components which have at least a base material and meta clay, and an activating solution is produced, wherein the activating solution has more than 5% by mass of alkali silicates, the mass of the base material is 200% to 500% of the mass of the meta clay and the ratio between the mass of the activating solution and the mass of the meta clay is greater than 1, and in a second step the mixture is shaped into a component using an extruder.

[0034] The composition according to the invention is first combined and mixed to form a substantially homogeneous mixture. In order to remove air bubbles from the composition, it is preferably provided that the composition is subjected to vibration and / or negative pressure after mixing. The composition is then formed into the desired shape using an extruder (or an extrusion press). For example, the extruder is used to form an endless profile of a component such as a brick, which is then cut off at regular intervals to form individual bricks.

[0035] After the component has been formed, it is preferably provided that the component is cured in a third step following the second step. Curing preferably takes place in ambient air, i.e. without the addition of heat or pressure. This makes it particularly easy to produce a component such as a brick which also has high compressive strength. It is preferably provided that the curing takes place at an air temperature of at least 20 °C and at least 50% air humidity (rH; relative humidity). Curing is particularly preferably carried out at an air temperature of 20 °C-30 °C and a relative humidity of 50% to 90%, preferably 50% to 80%. Under these conditions, curing is quick, cost-effective and cracks in the components are avoided.

[0036] Preferably, the mixing in the first step of the process is carried out as follows. First, the alkali silicate is mixed with water. A hydroxide is then dissolved in the alkali silicate-water mixture to obtain the activation solution.

[0037] Next, the solid components, namely a base material, especially clay and sand, are mixed with the meta-clay until a substantially homogeneous mass of solid components is formed. This step can be performed simultaneously, after, or before the preparation of the activation solution.

[0038] After the activation solution and the solid components have been prepared, the activation solution is added to the solid components and mixed until a substantially homogeneous and malleable mass is formed. This mass can then be used to manufacture a component.

[0039] Alternatively, the individual components of the composition may be mixed together in a different order to obtain a substantially homogeneous mass.

[0040] The invention is explained in more detail below with reference to an exemplary embodiment shown schematically in the drawing. Fig. 1 shows a schematic representation of a process according to the invention, which is essentially the same for the production of all three examples.

[0041] Fig. 1 shows a schematic representation of the sequence of a method according to the invention for producing a composition according to the invention. In section 1, an activating solution is produced. In section 2, solid components are produced. The mixing of the activating solution (section 1) and the mixing of the solid components (section 2) can take place simultaneously or at different times, for example one after the other. Then, in section 3, the activating solution from section 1 and the solid components from section 2 are combined. In section 4, a shape is formed from the composition formed in section 3, for example using a mold or an extruder. The shape is then cured in section 5.

[0042] Three examples of this procedure are described below.

[0043] Example 1

[0044] In the first step (1), 1.535 kg of potassium silicate is mixed with 0.768 kg of water. Subsequently, 1.075 kg of potassium hydroxide is dissolved in the potassium silicate-water mixture to obtain an activation solution. This activation solution contains approximately 45% by mass of alkali silicates in the form of potassium silicate.

[0045] Furthermore, the solid components, namely 2.205 kg of metakaolin, 5.066 kg of clay, and 5.066 kg of quartz sand, are mixed together in a forced-action mixer in the second section 2 until a substantially homogeneous mass is formed. The mass of clay and sand (quartz sand) amounts to approximately 460% of the mass of the meta-clay in the form of metakaolin.

[0046] The activation solution is then added to the solid portion in the third section 3 and mixed until a substantially homogeneous and kneadable mass is formed (first process step). The ratio between the mass of the activation solution (3.378 kg) and the mass of the meta-clay in the form of metakaolin (2.205 kg) is approximately 1.53. The ratio between the mass of the activation solution (3.378 kg) and the mass of the solid portion (12.337 kg) is approximately 0.27.

[0047] This malleable mass can now be used to manufacture a component. In this example, the mass is fed into the feeder of an extruder in the fourth section (second process step). In the extruder's vacuum chamber, the mass is deaerated, and a strand is extruded through the extruder's die. This strand is cut into smaller components, such as bricks, after exiting the extruder.

[0048] The resulting components are then cured in the fifth stage (third process step) at a minimum of 20°C and a minimum of 50% relative humidity. After 28 days, the compressive strength is determined, which is approximately 60 MPa.

[0049] Example 2

[0050] In the first step, 1.520 kg of sodium silicate is mixed with 0.520 kg of water. Then, 0.200 kg of sodium hydroxide is dissolved in the sodium silicate-water mixture to obtain an activation solution. This activation solution contains approximately 68% by mass of alkali silicates in the form of sodium silicate.

[0051] Furthermore, the solid components, namely 1,800 kg of metakaolin, 3,600 kg of clay, and 0,900 kg of quartz sand (with a grain size of 0.1 to 0.2 mm), are mixed together, for example, in a forced-action mixer in the second section 2, until a substantially homogeneous mass is formed. The mass of clay and sand (quartz sand) amounts to approximately 270% of the mass of the meta-clay in the form of metakaolin.

[0052] The activation solution is then added to the solid portion in the third section 3 and mixed until a substantially homogeneous and kneadable mass is formed (first process step). The ratio between the mass of the activation solution (2.240 kg) and the mass of the meta-clay in the form of metakaolin (1.800 kg) is approximately 1.24. The ratio between the mass of the activation solution (2.240 kg) and the mass of the solid portion (6.300 kg) is approximately 0.36.

[0053] This malleable mass can now be used to manufacture a component. In this example, the mass is fed into the feeder of an extruder in the fourth section (second process step). In the extruder's vacuum chamber, the mass is deaerated, and a strand is extruded through the extruder's die, which is then cut into smaller components, such as Mauser blocks.

[0054] The resulting components are then cured in the fifth stage (third process step) at a minimum of 20°C and at least 50% relative humidity. After 28 days, the compressive strength is determined, which is approximately 55 MPa.

[0055] Example 3

[0056] In the first step, 3.700 kg of potassium silicate is mixed with 0.700 kg of water. Then, 0.500 kg of potassium hydroxide is dissolved in the potassium silicate-water mixture to obtain an activation solution. This activation solution contains approximately 76% by mass of alkali silicates in the form of potassium silicate.

[0057] Furthermore, the solid components, namely 4,500 kg of metakaolin and 13,500 kg of quartz sand (with a grain size of 0.1 to 0.2 mm), are mixed together, for example, in a forced mixer in the second section 2, until a substantially homogeneous mass is formed. The mass of the quartz sand is approximately 300% of the mass of the meta-clay in the form of metakaolin.

[0058] The activation solution is then added to the solid portion in the third section 3 and mixed until a substantially homogeneous and kneadable mass is formed (first process step). The ratio between the mass of the activation solution (4,900 kg) and the mass of the meta-clay in the form of metakaolin (4,500 kg) is approximately 1.09. The ratio between the mass of the activation solution (4,900 kg) and the mass of the solid portion (18,000 kg) is approximately 0.27.

[0059] This malleable mass can now be used to manufacture a component. In this example, in section 4 (second process step), the mass is metered into a mold, e.g., for a brick, and compacted and deaerated on a vibrating table.

[0060] The resulting components are finally cured in the fifth section 5 (third process step) at at least 20°C and at least 50% rH (relative humidity).

[0061] After 28 days, the compressive strength is determined, which is approximately 65 MPa.

Claims

Patent claims:

1. Composition for producing components, comprising solid components which have at least one base material and meta-clay, and an activating solution, characterized in that the activating solution has more than 5% by mass of alkali silicates, the mass of the base material is 200% to 500% of the mass of the meta-clay and the ratio between the mass of the activating solution and the mass of the meta-clay is greater than 1.

2. Composition according to claim 1, characterized in that the base material comprises sand, the mass of the sand preferably being 10% to 500% of the mass of the meta-clay.

3. Composition according to claim 1 or 2, characterized in that the alkali silicates are sodium silicates and / or potassium silicates.

4. Composition according to claim 1, 2 or 3, characterized in that the activating solution contains between 20% and 90% by mass, particularly preferably between 30% and 50% by mass, of alkali silicates.

5. Composition according to one of claims 1 to 4, characterized in that the base material comprises clay, wherein the mass fraction of the clay is preferably 200% to 400% of the mass fraction of the meta-clay. 6 . Composition according to one of claims 1 to 5 , characterized in that the ratio between the Mass of the activating solution and the mass of the meta-clay is between 1.1 and 1.6, particularly preferably between 1.25 and 1.

35.

7. Composition according to one of claims 1 to 7, characterized in that the meta-clay comprises meta-kaolin.

8. A method for producing a component, in which in a first step a mixture of a composition comprising solid components which have at least a base material and meta-clay, and an activating solution is produced, characterized in that the activating solution has more than 5% by mass of alkali silicates, the mass of the base material is 200% to 500% of the mass of the meta-clay and the ratio between the mass of the activating solution and the mass of the meta-clay is greater than 1, and in a second step the mixture is shaped into a component using an extruder.

9. Method according to claim 8, characterized in that the component is cured in a third step following the second step.

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