Multi-component binder

Abstract

The invention relates to a multi-component binder which is flowable and solidifiable after the addition of water and forms strengthening phases when hardening. The multi-component binder comprises a first component containing clinker phases and a particulate second component, which has a pozzolanic effect; the second component is present in the form of secondary particles agglomerated from fine primary particles and is BET-surface area reduced with a BET surface area of in particular below 32 m2 / g, and has: an aluminum-containing silicate portion and a calcium-containing carbonate portion, which may also be present together in secondary particles; an X-ray amorphous portion of at least 25% and / or a reaction enthalpy according to ASTM C 1897 / 20 of at least 150 J / g; and bound water.

Description

[0001] MULTI-COMPONENT BINDER

[0002] This task concerns a multi-component binder which is flowable and solidifiable after the addition of water and hardens with the formation of strength-giving phases, with a first component containing clinker phases and a particulate second component with a pozzolanic effect.

[0003] The so-called cement clinker allows the strength-giving phases, so-called CSH and CASH phases, to form later when the binder is used via hydraulic reactions. The clinker phases from, for example, Portland cements (worldwide Portland cement demand is around 4 billion tonnes annually) often represent the main component of such binders. Just as Portland cements provide clinker phases for such binders, multi-component binders such as composite cements have additional components in the form of main cement components or minor components / additives for various purposes. Such additives for, for example, cements, concretes or other hydraulic binders or building materials are widely known in technology and serve to improve one or more properties of the building materials in use right down to the parts manufactured from them.They also provide a range of properties in addition to the by-products from other processes such as steel or energy production that have long been known in the historical development of building material systems based on such building materials and that continue to be used.

[0004] Bulk raw materials are available for the production of such multi-component binders, such as natural (trass, pumice, etc.) or artificial pozzolans (fly ash) or even slags (granulated blast furnace slag, low-density slag, etc.). Their use is regulated by standards. For example, the European cement standard DIN EN 197 represents the first European harmonized product standard, which, due to its classifications, still leaves scope for numerous different concrete standard-compliant implementations. For reasons of durability, the use of clays in numerous cement types is limited, either directly or indirectly via their content in limestone flour as a possible main cement component. For example, according to DIN EN 197-1, the clay content in the main cement component, limestone flour, determined using the methylene blue method according to DIN EN 933-9, must not exceed 1.20 g / 100 g.In addition, German and European regulations limit the clay content in aggregates to be used in concrete production to less than 0.5% and, in special cases, to less than 0.25%.

[0005] There are also artificially produced substances, e.g. as pozzolanic substances such as typical and commercially available microsilica, which are used as concrete additives or main cement components, with their very high SiO2 contents, e.g. of 97% (e.g. white microsilica Q1 from BCK Bau-Chemie-Kontor Vertriebs-GmbH).

[0006] A so-called EMC cement was developed at Lulea University of Technology in Sweden and presented at the ICCC in Montreal in 2006. By grinding a raw material consisting of Portland cement and silica dust in vibrating mills, a strength increase lasting several months was achieved, with compressive strength even up to 100% higher at one day of age. EP 0 517 869 B1 describes how a carbonate donor is added to a Portland cement-based system with the aim of quickly achieving higher strengths. Additives such as sodium carbonate, sodium sulfate, and calcium hydroxide are described in DE 4223494 C2, also for achieving high early strengths.

[0007] Treated glassy volcanic rocks such as air-dried pumicete can also act as additives or substitutes, but with significantly longer treatment times than suggested in DD 141788 A1 in connection with increasing the solubility of aluminum oxide from clays, namely preferably in the range of 8 to 16 hours, which eliminates the disadvantage of an otherwise very limited binding capacity of volcanic glasses and thus opens the way for such volcanic glasses to be used as cement additives, as described in DE 2816322.

[0008] Slags from other processes are also proposed as usable residual materials. For example, EP 3 322 534 B1 describes a process for the ultrafine grinding of LD steel mill slag. The grinding process, followed by classifying, is intended to release belite and alite surfaces from the finely ground slag particles. Furthermore, the resulting pressure comminution increases the reactive surface area and leads to increased hydraulic reactivity.

[0009] Similarly, US 66,30,022 B2 paves the way for crushed sands as a cement additive, which are produced during the production of granite gravel and would otherwise be disposed of as waste.

[0010] EP 2 253 600 A1 proposes supplementing cement clinker with calcined clays, such as metakaolin. For example, in the temperature range between 600°C and 920°C, the clay mineral kaolinite is transformed into a highly reactive pozzolanic substance, which can be classified as natural tempered pozzolan (Q). This is also considered to have a more favorable CO2 balance, because if one ton of cement clinker (which correlates with a release of 800 kg CO2, about 2 / 3 of which is due to the raw material from the deacidification of the main raw material limestone and about 1 / 3 of which is due to the fuel from the generation of the high process temperatures in the rotary kilns used) is replaced by calcined clay, the resulting converted value is only approximately 200-300 kg CO2 release per ton of calcined clay due to the required lower release of raw material-related CO2 and the lower energy required for clay calcination.Such calcination can be carried out in a calcining furnace after grinding, as disclosed in DE 10 2011 014 498 A1, or already in a mill through which hot gas continuously flows to thermally provide the calcination temperatures at temperatures of preferably between 500°C and 750°C, together with removal of the previously contained water of crystallization, as disclosed in EP 3 909 682 B1.

[0011] However, if one were to forego such thermal energy input and achieve increased hydraulic reactivity through mechanical fine grinding, as is the case with EMC cements, the evaluation of scientific laboratory tests already suggests that the required energy input, extrapolated to approximately 2.5 MWh per ton (assuming approximately 420 g of CO2 per kWh of electrical energy used today - UBA Electricity Mix Germany 2021), would lead to a significantly worse result of over one ton of CO2 release per ton of material. Furthermore, as described in Materials 2018, 11, 1860, llda Tole et al., undesirable effects occur that could negate the very high grinding fineness achieved for the desired increase in reactivity.Alternative main cement components such as fly ash, granulated and ground granulated blast furnace slag are also available as proven main cement components that can be used to reduce the clinker content in the multi-component binder if necessary.

[0012] Another binder system is described in DE 4313148 A1, in which a sulfate carrier and a setting retarder as well as additives in the form of microsilica or metakaolin as a rebound reducing additive (for shotcrete), as well as sodium citrate and lignin sulfate are added to Portland cement, deliberately avoiding aluminate-containing setting accelerators.

[0013] DE 21 2012 000 163 U1 discloses a concrete additive with a pozzolanic carrier made of spherical fly ash for a photocatalytic material. The addition of halides is initially described in EP 1 719 742 A1 as being particularly effective for accelerating the formation of CSH phases. However, this document proposes ultrafine calcium hydroxide with a very high specific surface area and small grain sizes for the formation of high early strengths.

[0014] Each of the binders listed above has its own specific advantages and disadvantages depending on its composition.

[0015] The invention is based on the object of advantageously developing a multi-component binder of the type mentioned at the outset, in particular with a view to a suitable combination of a satisfactory achievable compressive strength and durability with, at the same time, acceptable manufacturing costs.

[0016] This object is achieved by the invention by providing a multi-component binder of the type mentioned at the outset, which is essentially characterized in that the second component is in the form of secondary particles agglomerated from fine primary particles, BET-surface-reduced, with a BET surface area of ​​in particular less than 32 m 2 / g, has an aluminum-containing silicate component and a calcium-containing carbonate component, also present together in secondary particles, has an X-ray amorphous content of at least 25% as determined by diffractrometry and / or a reaction heat development according to ASTM C 1897 / 20 (R3 test) of at least 150 J / g, and has bound water. The properties listed here refer to the second component as such and not to the binder as a whole.

[0017] Thus, the invention provides a multi-component binder which, among other things, may have a comparatively low Portland cement clinker content and yet achieves attractive mechanical strengths, good processability and also good durability properties.

[0018] According to the invention, the second component thus contains bound water. Determined by mass loss due to water release during thermogravimetric analysis (DIN 51006:2005-07) in the temperature range between 130°C and 400°C, the water content is preferably at least 0.8%. However, even higher water contents are more preferably present, namely at least in the form of a water loss determined in this way of more than 1.2%, more preferably more than 1.6%, even more preferably more than 2%, and also more than 2.5%, even more than 3%. Values ​​of more than 3.4%, even more than 3.8%, and even more than 4.2% are also conceivable. However, the water content determined in this way should preferably not exceed 15%, more preferably 10%, even more preferably 8%, and in particular not exceed 6%. When using the binder, it has proven advantageous if water is at least partially present not only on the outside of the binder particles orthe second component, but water molecules are already bound within these secondary particles by agglomeration. This may contribute to early CSH phase formation when the binder is used, as well as advantageous processing properties. The bound water may have resulted from mechanical dehydroxylation and its incorporation may also occur by dehydroxylation. Such bound water (H2O molecules) is no longer present in calcined clays due to the high temperatures applied during their production. If a thermogravimetric analysis of such a calcined clay shows a loss of mass, this is due to incomplete dehydroxylation.

[0019] In addition to the agglomeration provided for in the invention, there is a binding effect of the primary particles in the form of atomic bonds that goes beyond the adhesion caused by Van der Wals forces.

[0020] Preferably, the BET surface area (BET surface area determination according to Brunauer, Emmet, Teller, nitrogen BET, standard determination according to DIN 66131) is below 32 m 2 / g, even below 30 m 2 / g, even below 28 m 2 / g, even below 26 m 2 / g. This further reduces the water demand of the multi-component binder, insofar as it is attributable to the pozzolanic second component. The second component (considered alone) preferably has a Puntke water demand of more than 20%, preferably more than 22%, in particular more than 25% and / or not higher than 45%, more preferably not higher than 42%, in particular not higher than 40%. However, the BET surface area of ​​the second component should preferably not be less than 4m 2 / g, more preferably not less than 5m 2 / g, in particular not less than 6m 2 / g. The particle size of the primary particles, on the other hand, can be in the range of no more than 300 nanometers, even less than 250 nm, or even 200 nm.

[0021] The reaction heat evolution of the second component (during hydration over 7 days according to ASTM C1897-20) is preferably at least 180 J / g, more preferably at least 210 J / g, especially at least 240 J / g. The X-ray amorphous fraction determined by diffraction (Rietveld XRD (internal standard)) is preferably at least 28%, more preferably at least 31%, especially at least 34%. This fraction can preferably even be at least 40%, even more than 44%.

[0022] In a preferred embodiment, the second component has an activity index SAhs according to EN 450-1 of at least 78%, and in particular the SAhs measured in percent with the reaction heat development r measured in J / g according to ASTM C1897-20 in the relationship fr r+65 - t < SAl28< fr r+65+t stands, with f r in the range [0.08; 0.14], in particular [0.1; 0.12] and t equal to 15, preferably equal to 10, in particular equal to 7, and / or with the amorphous fraction x measured in percent in the relationship fx-x+65 - 1 < SAI 28 < fx-x+65+t stands, with f x in the range [0.75; 0.85], in particular [0.78; 0.82] and t equal to 15, preferably equal to 10, in particular equal to 7. In a further preferred embodiment, it is provided that the second component has an activity index SAI28 according to EN 450-1 of at least 84%, more preferably even at least 88%. However, even higher values ​​of 96%, even over 100%, can be achieved, which are also preferred. These SAI28 values ​​refer to the second component alone, when determined according to the determinant standard, and are independent of the composition of other binder components of the binder.

[0023] In a preferred embodiment, it is provided that the second component has a value of less than 1.2 g / 100 g in a methylene blue test (DIN EN 933-9), and in particular between the methylene blue value m measured in g / 100 g and the SAI28 measured in percent, the relationship f m m+104 - tm < SAI 28 < f m m+104+tm applies, with f m in the range [-24; -16], in particular [-22; -18] and tm is 20, preferably 16, in particular 12.

[0024] In a preferred embodiment, the mass loss w measured in percent is calculated with the SAI measured in percent 28 in this context fw W+70 - tw < SAI 28 < f w w+70+tw stands, with f w in the range [5; 11], in particular [7; 10] and tw equal to 15, preferably equal to 12, in particular equal to 10, and / or with the amorphous fraction x measured in percent in the relationship f xw x -0.9 - txw < w < f xwx -0.9+txw stands, with f xw in the range [0.05; 0.11], in particular [0.06; 0.1] and txw equal to 1.2, preferably equal to 0.8, in particular equal to 0.6.

[0025] In a preferred embodiment, the second component has a reactive SiO2 content according to DIN EN 197-1 of greater than 12%, preferably greater than 15%, more preferably greater than 20%, even greater than 25%, preferably greater than 28%, in particular greater than 32%, and in particular the reactive Al2O3 content is at least 10%. Thus, the hydraulic binder, thanks to the very high pozzolanic activity achieved by the second component, can meet the normative and building regulations requirements of the European cement standard even in larger quantities and can be used accordingly.

[0026] In a preferred embodiment, it is provided that the X-ray amorphous portion is an X-ray amorphous portion generated at least in part by an increase in the internal energy of the material experiencing the energy input, caused by mechanically induced energy input simultaneously at the same point of action on the silicate portion and the carbonate portion.

[0027] The mechanically induced increase in internal energy is reflected in a partial phase transformation and / or the formation of defect structures in the mineral phases. The massive generation of crystal defects, up to and including complete amorphization of the material, leads to a correspondingly large increase in internal energy. Thus, mechanically induced energy components stored in the solid are available. It has been recognized that through intimate mixing and the shared energy input, a synergistic interaction is achieved between the components, for example, clay minerals and limestone / dolomite components, which positively influences reactivity beyond their separate processing and mixing.

[0028] In a further preferred embodiment, the material undergoing the energy input contains crystalline quartz, as a natural component or added before or during the exposure.

[0029] The presence of such mechanically induced energy components stored in the solid can be detected, for example, by solution calorimetry according to DIN EN 196-8, which is based on the complete dissolution of the material in a hydrofluoric acid-nitric acid mixture. Comparing these solution calorimetric results with those of the starting material ground to analytical fineness for only 3 minutes in a laboratory vibrating disc mill yields the so-called excess enthalpy, or the free perturbation enthalpy AH*, which is a measure of the energy components actually mechanically induced and stored in the solid. For the second component of the multi-component binder according to the invention, the excess enthalpy is at least 50 J / g, preferably at least 100 J / g, in particular at least 150 J / g.

[0030] In this respect, the pozzolanic properties of the second component derive, at least in part, from the increase in internal energy experienced at the point of impact. The manner in which the mechanically induced energy input is achieved is not particularly limited and depends, among other things, on the type of impact site. The external energy input provided for this purpose can be adjusted via the amplitudes and speeds or accelerations of grinding media, depending on the grinding or milling technology used. For technical implementation, the expert has access to mechanoreactors in the form of various grinding systems for the impact site, with high-energy grinding systems being preferred. For example, this could be a micromill in the form of a vibrating mill, a planetary ball mill, or an agitated ball mill.A particularly preferred grinding technique for this purpose is the agitated ball mill, in particular the horizontal agitated ball mill. Such a agitated ball mill could have a length-to-diameter ratio of at least 2.3, preferably at least 2.5, in particular at least 2.6, and / or less than 5.2, more preferably less than 5, in particular less than 4.8.

[0031] Grinding media could be filled in a bulk volume, based on the grinding chamber volume, of at least 48 vol%, preferably at least 54 vol%, more preferably at least 60 vol%, in particular at least 72 vol%, and / or with a proportion of not more than 96 vol%, more preferably not more than 88 vol%, even more preferably not more than 78 vol%, in particular not more than 69 vol%. The space actually available for the material to be treated is naturally higher than the remaining percentage, since the filling degree for a simple bed must also be taken into account in the calculated remaining grinding chamber volume (even with a theoretical grinding chamber volume completely filled with bulk volume, free space still remains, even assuming the closest packing of spheres in the bed).There are no particular restrictions regarding the grinding media; however, grinding media made of iron or an iron alloy such as steel are preferred. Grinding media made of aluminum oxide or other ceramic materials, such as zirconium oxide, can also be used. There are also no particular restrictions regarding the grinding media dimensions; preferred diameters are in the range of greater than 0.8 mm, preferably greater than 1 mm, in particular greater than 1.2 mm and / or less than 12 mm, more preferably less than 10 mm, in particular less than 9.2 mm. Alternatively, ceramic grinding media, for example, could also be used.

[0032] With regard to the peripheral speed of the impact tool of the agitator ball mill, peripheral speeds of preferably at least 1.8 m / s, more preferably at least 2.6 m / s, even more preferably at least 3.2 m / s, in particular at least 3.6 m / s are contemplated. On the other hand, it is also preferred that this peripheral speed is not higher than 6.4 m / s, more preferably not higher than 5.8 m / s, in particular not higher than 5.1 m / s, and furthermore not higher than 4.4 m / s. The external energy input, which initially results in fine grinding to very small primary particles and then also in the mechanically induced increase in internal energy, is coordinated with the exposure time in such a way that the inventive BET surface area-reducing agglomeration to secondary particles takes place.It is understood that the transition to agglomeration after the initial formation of the finest primary particles due to mechanical (comminution) action (and an intermediate aggregation phase before the onset of agglomeration) depends on the starting material, but can be determined in a conventional, expert manner, similar to the determination of the particle fineness threshold in the so-called Rittinger zone during mechanical activation. Mechanical action for the mechanically induced energy input is preferably carried out via a dry treatment.

[0033] Within the scope of the invention, it has thus been recognized that it can be advantageous to allow the action to take place beyond a point at which the limiting fineness of an initially occurring particle reduction is reached, for which, correlating with extremely high BET surface areas, the form which actually causes the very high hydraulic activity desired is already present, which, however, requires further energy input in terms of energy input technology.

[0034] The mechanical action leading to the mechanically induced energy input results, among other things, in pressure, shear, and friction forces between colliding surfaces (of the material and the boundary of the impact site and / or other collision partners such as grinding media). With the high-energy mills described here, a satisfactorily high normal component of the collision momentum of such colliding impact events is achieved. The mechanical stress on the material allows a satisfactory increase in internal energy with a surprisingly low specific total external energy input of preferably no more than 1200 kWh per ton of material of the second component, in particular no more than 1000 kWh per ton, which represents only a fraction of the values ​​considered necessary for pure grinding to the limiting fineness alone, namely up to an estimated 2500 kWh per ton.Within the scope of the invention, it was thus also recognized that, not least due to the difficulty of direct comparability of scientific studies, the properties usually measured or calculated on phase-pure model substances are unsuitable for describing such processes on an industrial scale. Furthermore, it was recognized that the mechanically induced energy input by simultaneously acting on the silicate and carbonate components of the starting material at the same point of action leads to an increase in reactivity that goes beyond the filler effect of limestone flour or silicate components. In this respect, a satisfactory increase in performance can be achieved simply by combining clay-like and limestone-containing components in the starting raw material.

[0035] In this context, the water content of the second component is due to mechanical dehydroxylation of clay minerals / sheet silicates, which are preferably present in the starting material, at the site of exposure. During the mechanical action, hydroxyl ions of the clay minerals are converted into water molecules through a prototropic process, which attach to the mechanically activated particles and are incorporated into the second component through agglomeration.

[0036] In this respect, the second component has the property of a water-containing xerogel with regard to the water bound therein, and therefore the second component is occasionally referred to below as a clay-based xerogel.

[0037] In a preferred embodiment, it is provided that the exposure site for producing the clay-based xerogel is an achievable volume of at least 2000 l, preferably at least 4000 l, in particular at least 10,000 l, of which at least 10%, preferably at least 15%, in particular at least 20% and / or at most 60%, further preferably at most 50%, in particular at most 40% is simultaneously accessible to the material experiencing the energy input.

[0038] In a preferred embodiment, the exposure site is a location where, in addition to the mechanically induced energy input, a fine grinding of the (layered) silicate portion and / or carbonate portion takes place starting from a starting material supplied to the exposure site, and in particular, it is an exposure site with an average residence time of the silicate portion and the carbonate portion that does not exceed one hour, preferably does not exceed 50 minutes, in particular does not exceed 40 minutes. In this context, it has been recognized that for the production of the second component of multi-component binders according to the invention, no exposure at the exposure site for several hours or even days is required.In a preferred embodiment, the exposure site is a site of exposure in a particularly moving atmosphere, and / or a site of exposure at a temperature of no more than 250°C, preferably no more than 170°C, more preferably no more than 140°C, in particular no more than 120°C. The temperature at the exposure site is a result of the mechanical action (intrinsic heat of the grinding process); active thermal heating is not envisaged, since according to the invention, bound water is intended to remain in the material of the second component. In this context, it has been recognized that despite the removal of vaporous water due to a moving atmosphere, in contrast to a constant atmospheric presence including collected vaporous water, the retention of the water bound in the second component is not hindered.Thus, the invention specifically does not relate to calcined clays or clays that have been subjected to an active thermal treatment typically used for their calcination. Regardless of the location(s) of exposure (or outside of the location(s), the material of the second component should not be exposed to higher temperatures, not even higher than those specified above (in the same preferred range).

[0039] With regard to the atmosphere, it is preferred that a gas stream is used, wherein ambient air can be used or one or more gases of the gas stream can be selected from the group nitrogen, argon, carbon dioxide, water vapor, carbon monoxide, hydrogen, hydrocarbon, in particular methane, ethane, propane and / or butane. In a preferred variant, the predominant gas component (in vol.%) is nitrogen, carbon dioxide and / or water vapor. It is further preferred that the gas contains no more than 1.2 vol.%, more preferably no more than 0.6 vol.%, even more preferably no more than 0.2 vol.%, in particular no more than 0.09 vol.% oxygen.

[0040] If, for example, a stirred ball mill is fed with such a gas volume flow for the atmosphere being formed, a ratio of gas volume flow to material flow of more than 0.001 m 3 / kg, preferably more than 0.001 m3 / kg, more preferably more than 0.11 m 3 / kg, whereby this ratio is preferably not more than 5 m 3 / kg, more preferably not more than 3 m 3 / kg, in particular not more than 1.9 m 3 / kg. Nevertheless, it could be provided to keep the exposure site at a temperature of not less than 84°C, more preferably not less than 92°C, in particular not less than 102°C.

[0041] In a preferred embodiment, the silicate portion as well as the carbonate portion originates from a starting material supplied to the site of action, in particular a silicate portion or carbonate portion formed by grinding there, and the starting material consists at least partially and preferably predominantly of a preferably pretreated clay material, in particular at least 25 wt.%, preferably at least 35 wt.%, and particularly preferably at least 40 wt.% of clay minerals, including all amorphous constituents of the clay material belonging to the group of kaolinites, illites, smectites, chlorites, pyrophyllites, or the vermiculite group, or mixtures thereof. Although kaolinite is a favorable clay mineral from the perspective of the invention, variants are also conceived in which the kaolinite content in the second component can be less than 15%, even less than 13%, or even less than 10%.

[0042] In a preferred embodiment, a starting material for forming the second component can thus be a clay material. Within the scope of the invention, clay is not defined in terms of grain size, but rather includes the presence of silicate minerals such as phyllosilicates or framework silicates. Examples of starting materials can thus include the aforementioned two-layer clay minerals, three-layer clay minerals, or even four-layer clay minerals, as far as phyllosilicates are concerned, but also various framework silicates. In this respect, the starting material can also contain so-called associated phases such as quartz or various iron oxides or iron oxide hydroxides.Such starting materials in the form of clay material are preferably already present at the impact site in a crushed, dried, and pre-crushed (coarsely crushed) form, in a manner typical for pretreatment prior to use in one of the mills available for the impact site. The mill can then grind to finer primary particles, agglomerate to secondary particles, and increase the internal energy through further energy input. It is understood that this process could also be divided between two or more locations (mills), such as a mill cascade. However, this process preferably takes place in a single mill.

[0043] In this context, it has been recognized that the increased pozzolanic effect achieved by calcined clays can be dispensed with and satisfactory pozzolanic reactivity can still be achieved. Furthermore, it has been recognized that good durability aspects of structures manufactured with a multicomponent binder according to the invention can also be achieved using clay-containing starting materials.

[0044] In a preferred embodiment, the increase in internal energy is at least 50 J per gram of the material at the site of impact, preferably more than 100 J / g, more preferably more than 150 J / g, in particular more than 200 J / g. Even higher values ​​of more than 300 J / g, more than 400 J / g, or even more than 500 J / g are also conceivable with an even higher energy input.

[0045] In a preferred embodiment, it is provided that the second component has a weight ratio of carbonate content calculated in [CO2] to a silicate content calculated in [SiOa] of at least 10%, preferably at least 20%, in particular at least 30% and / or at most 2, more preferably 1.5, in particular at most 1.

[0046] The carbonate content, preferably at least 5% by weight in absolute terms, can consist partly of calcite and / or dolomite and preferably consists predominantly of dolomite. In this context, it is preferred that, if a clay component of the starting material (which could otherwise also form the starting material as a whole) does not reach such a preferred carbonate content, the starting material also has one additional carbonate component. Due to the mechanically induced action at the site of action, defect structures are also created in such calcium-containing carbonates, possibly even leading to the formation of amorphous carbonate phases (ACC, amorphous calcium carbonate). The starting material, which is mechanically acted upon at the site of action, could also contain other materials, etc.a as additionally added materials, for example more than 0.12 wt% hard rock, preferably also at least 0.4 wt% quartz and / or corundum, whereby this proportion should preferably not be more than 50 wt%, in particular not more than 48 wt%, e.g. at least 5 wt% crystalline quartz can be added additionally.

[0047] In addition, the action at the site of action could be carried out using a solid or liquid reducing agent, for example to prevent oxidation of iron, for example, or to bring about a reduction of trivalent iron. Such a reducing agent could, for example, be in the form of metals or coal dust, or in the form of liquid hydrocarbons. Such an addition could also be used to adjust the visual appearance of the second component, for example, a desired shade of gray. In one proposed design, it is envisaged that a quantity of a carbonate material added separately to the clay material of the starting material contributes to the ratio of carbonate content to silicate content.

[0048] In a preferred embodiment, the point of action is a grinding chamber of a mill operated in continuous operation, in particular a stirred ball mill of a particularly horizontal design, which has a power of at least 200 kW per m 3grinding chamber volume, preferably with a throughput of at least 60 kg per hour, more preferably of at least 120 kg per hour, even more preferably of at least 180 kg per hour, in particular of at least 240 kg per hour and in particular with an energy supply (external total energy consumption) of more than 200 kWh, even more than 300 kWh, possibly even more than 400 kWh, but preferably also less than 1200 kWh per ton of treated material. In addition, throughputs of more than 480 kg / h, even more than 1 t / h, even more than 2 t / h are envisaged. In this respect, contrary to expected assumptions of very high energy consumption even for achieving the smallest primary particles, the energy consumption for producing the multi-component binder, in particular its second component, can be at least kept within limits and thus an overall reduction in CO2 emissions can be achieved.In this context, it has also been recognized that batch operation is also unnecessary for the provision of extremely high BET surface areas, and that the second component of such multi-component binders can even be achieved if the (starting) material undergoing the exposure passes the exposure site at a high throughput as stated above, i.e., already on the order of industrial throughputs. In this context, it has also been recognized that, surprisingly, a scale effect also occurs, which becomes noticeable at such high throughputs in the form of significant increases in specific throughput without any significant loss of performance in product quality.

[0049] In particular, if the point of action is the mill volume (grinding chamber volume) of a continuous agitator ball mill, per m 3Mill volume, an energy input is provided by means of a power of preferably at least 100 kW, more preferably at least 160 kW, more preferably at least 200 kW, in particular at least 240 kW. In addition, it is preferred that such an introduced energy input does not exceed 800 kW / m 3 , more preferably not more than 750 kW / m 3 , in particular not more than 700 kW / m 3Such a stirred ball mill could be a vertical stirred ball mill or a horizontal stirred ball mill, with the horizontal stirred ball mill being again preferred. When using, for example, a stirred ball mill, the second component is preferably the material obtained at the outlet end of the impact site without re-entering the impact site (without recirculation and repeated passage). According to the invention, screening by means of various screening systems and recirculation of material below a certain degree of comminution preferably does not take place, at least in one variant. In another variant, screening could take place downstream of the outlet end of the impact site, but rather the coarse fraction would be recirculated, not as is otherwise usual, but the fine fraction.This variant allows even greater flexibility for the process parameters used to achieve the desired lower BET surface area of ​​the second component.

[0050] In principle, however, it is conceivable to have another upstream action site in which grinding to particles takes place at least partially, e.g. close to the limit fineness, even starting from already crushed material.

[0051] In a preferred embodiment, the second component has a particle size distribution according to photo-optical analysis (CCD cameras / CAMSIZER) of Q3(10): < 4.5 pm; Q3(50): < 15 pm; Q3(90): < 40 pm. 90% of the sample volume therefore consists of particles with a diameter of < 40 pm. In addition to or independently of the particle size distribution, the particles of the second component have an average sphericity value (SPHT3) of greater than 0.84. Volumetric parameters Q3(10), Q3(50), and Q3(90) mean that 10%, 50%, and 90% of the sample volume consists of particles with a smaller diameter than the respective value. The sphericity SPHT3 describes the roundness of the particles and has a maximum value of 1. Sphericity SPHT3 indicates the roundness, which is determined from the particle circumference U and the particle area A. Perfect circles or spheres have a sphericity equal to 1. For all other shapes, the sphericity is < 1 (SPHT = 4WVU2).

[0052] In a preferred embodiment, the first component is present in a weight proportion of at least 30% and the second component in a weight proportion of at least 5%, preferably at least 10%, more preferably at least 15%, in particular at least 20%, but preferably no more than 60%, in particular no more than 50%. The multi-component binder could contain limestone powder as a third component, preferably at least 2%, more preferably at least 5%, in particular at least 10%. In this case, the multi-component binder has a limestone component in the form of at least two distinguishable reactive qualities, namely that of the third component and that of the carbonate portion of the second component.

[0053] Such provision of different reactive qualities can also be sought for the silicate portion. In this context, it is contemplated that the multi-component binder may comprise a fourth component, optionally with a pozzolanic effect. This fourth component could be in the form of microsilica, calcined clay, or yet another component and / or mixtures thereof, and preferably present in a proportion of at least 2%, in particular at least 5%. Further components may also be included (S preferably in a proportion of no more than 40%, Q preferably in a proportion of no more than 20%, V preferably in a proportion of no more than 30%, W preferably in a proportion of no more than 30%, T preferably in a proportion of no more than 30%, and / or D preferably in a proportion of no more than 10%, and in each case, if used, preferably in a proportion of at least 5%).

[0054] Furthermore, the invention also independently protects the material constituting this second component and thus also relates to a material that can be used as a cement component, in particular as a main cement component, in the form of a pozzolanic particulate material that is in the form of secondary particles agglomerated from fine primary particles with a BET surface area reduced and preferably less than 32 m 2 / g, has an aluminum-containing silicate portion and a calcium-containing carbonate portion, also present together in secondary particles, has an X-ray amorphous portion of at least 25% and / or a reaction heat development according to ASTM C 1897 / 20 of at least 150 J / g, and has bound water. It is understood that all the features and properties set out above for the second component of a binder according to the invention also apply to the particulate material forming this second component on its own and are thus disclosed.

[0055] This material could be used as a cement component, in particular as a main cement component, but also generally as a pozzolanic additive in the building materials sector, for example for mortar or as a stand-alone addition to concrete mixtures or otherwise. For this purpose, the invention also protects a deposit containing a quantity of not less than 2 tons, preferably not less than 4 tons, in particular not less than 10 tons of this material. Further features, details and advantages of the invention will become apparent from the following description with reference to the accompanying figures, of which

[0056] Fig. 1 shows a relationship between SAhs and the reaction heat development of pozzolanic materials (or the second component),

[0057] Fig. 2 shows a relationship between SAI28 and the X-ray amorphous fraction of pozzolanic materials,

[0058] Fig. 3 shows a relationship between SAhs and methylene blue values ​​of pozzolanic materials,

[0059] Fig. 4 shows a relationship between thermogravimetric water loss and SAI28 pozzolanic materials,

[0060] Fig. 5 shows a relationship between thermogravimetric water loss and the X-ray amorphous fraction of pozzolanic materials, and

[0061] Fig. 6 shows a 5000x and 10,000x magnified image of agglomerated particles of the pozzolanic material.

[0062] A first embodiment is a multi-component binder with 55% (always wt.%) CEM I Portland cement corresponding to a clinker content of 50%, a content of the second component of 25%, as well as 19% limestone flour and small residual components of conventional additives.

[0063] The composition of the starting material for the formation of the second component was a clay with: 51.7% SiO2, 13.6% AI2O3, 6.8% Fe2O3, 6.2% CaO, 2.9% K2O, 5.9% MgO, 0.3% Na2O, 0.7% TiO2 and residues totaling approximately 11.9%, where the % is to be understood as wt% containing ignition loss (including - 8.1% CO2).

[0064] A mineralogical analysis of this clay from the first embodiment (XRD Rietveld analysis (internal standard)) revealed a total clay mineral content of just under 44%, expressed as a percentage, including approximately 4.8% kaolin, 19.7% muscovite, 1.6% illite, 15.3% chloride, and 2.2% montmorillonite. The other phases comprised 23.7% quartz, 17.1% dolomite, and 1.2% calcite, with an amorphous fraction of just under 14%. Various parameters were determined experimentally for the second component (clay-based xerogel) of the first embodiment, produced from this starting material. The result was an SAI28 of 106%. The proportion of reactive SiO2 (EN 197-1) was 30.2%.

[0065] This clay-based xerogel of the first embodiment has a latent heat of hydration (ASTM C1897-20) of 330 J / g. The amorphous fraction according to XRD of the clay-based xerogel in this embodiment was 50%, and the methylene blue test yielded 0.2 g / 100 g. The water content of this clay-based xerogel of the first embodiment was 2.6%. The water content of the xerogel according to Puntke is 33%.

[0066] A second embodiment uses the clay-based xerogel of the first embodiment, but the multi-component binder mixture consists of 55% Portland cement (CEM), corresponding to a clinker content of approximately 50%, the clay-based xerogel as above in a proportion of 13%, as well as 19% limestone flour and 13% granulated blast furnace slag. In another variant, also with the same second component, the proportion was 25%, with a 75% proportion of CEM / Portland cement.

[0067] Third embodiment: In this embodiment, the composition with regard to the components of the multi-component binder is as in the first embodiment.

[0068] The composition of the starting material for the formation of the second component was clay as in the first embodiment, but the second component (hereinafter clay-based xerogel) of the third embodiment has the following values ​​compared to the above measured values ​​of the clay-based xerogel of the first embodiment in corresponding measurements due to a different energy input (changed (halved) throughput):

[0069] The resulting SAI28 was 110%. The proportion of reactive SiO2 (EN 197-1) was 35%.

[0070] The clay-based xerogel of the third embodiment has a heat of hydration (R3 test according to ASTM C 1897-20) of approximately 431 J / g. The amorphous fraction according to XRD of the clay-based xerogel in this embodiment was 57%, and the methylene blue test yielded approximately 0.13 g / 100 g. The water content of this clay-based xerogel of the third embodiment was 2.4%. The water content of the xerogel according to Puntke was determined to be 34%.

[0071] In a fourth embodiment, the composition of the multi-component binder components is the same as that of the second embodiment.

[0072] The composition of the starting material for the formation of the second component was a clay with: 23.0% SiC>2, 8.8% AI2O3, 3.9% Fe2O3, 30.7% CaO, 1.9% K2O, 1.5% MgO, <0.1% Na2O, 0.4% TiO2 and residues totaling approximately 29%, where the % is to be understood as weight% containing loss on ignition.

[0073] For the second component (hereinafter clay-based xerogel) of the fourth embodiment, a SAI 28 of 95%. The proportion of reactive SiO2 (EN 197-1) was 24%. The clay-based xerogel of the fourth exemplary embodiment had a heat of hydration (R3 test according to ASTM C 1897-20) of 198 J / g. The amorphous fraction according to XRD of the clay-based xerogel in this example was 55%; the methylene blue test resulted in 0.33 g / 100 g. The water content of this clay-based xerogel of the fourth exemplary embodiment was 3.9%. The water content of the xerogel according to Puntke was determined to be 34%.

[0074] To produce the clay-based xerogel of the first embodiment, a horizontal agitated ball mill with a grinding chamber volume of 300 l and a raw material feed rate of 100 kg per hour was operated. The grinding media filling ratio was 65%, with steel balls (6 mm diameter) used as the grinding media. The agitated ball mill had a length-to-diameter ratio of 4 and was operated at a peripheral speed of 4 m / s, with a gas flow to material flow ratio of approximately 0.01 m 3 / kg. With a grinding media filling level of 65%, the agitated ball mill was operated at a power of 350 kW per cubic meter. The residence time in the grinding chamber was 30 minutes, and the material temperature was controlled by exhaust air to a maximum of 80°C. The specific external mechanical energy input, i.e., the energy generated by the mill during continuous operation of the agitated ball mill, was 1090 kWh per ton of material.

[0075] For the third embodiment, the clay-based xerogel (the second component) was also produced using a horizontal agitator ball mill, but with different settings, essentially doubling the energy input by halving the feed rate. For the fourth embodiment, the starting material for producing the clay-based xerogel was treated as in the first embodiment.

[0076] Further embodiments with varied parameters regarding the control of throughput and corresponding energy input are not explicitly listed; measurement results from them are shown in Figures 1 to 5.

[0077] Fig. 1 provides examples of clay-based xerogels with reference to heat of hydration according to ASTM C 1897 / 20 (abscissa with unit [J / g]) and SAhs according to EN 450-1 (ordinate). In Fig. 2, the amorphous fraction according to XRD Rietveld (internal standard) is plotted in percent on the abscissa, with the ordinate remaining the same as in Fig. 1.

[0078] Also in Figures 3 and 4, the ordinate denotes SAhs, in Fig. 3 the methylene blue value m according to DIN EN 933-9 is given in the abscissa, whereas in Fig. 4 the mass loss reflecting the water content is given in percent in the abscissa.

[0079] Fig. 5 shows exemplary embodiments with regard to the amorphous fraction (abscissa, in percent) and the mass loss (ordinate, in percent).

[0080] In a further embodiment, a starting material is predominantly that of the first embodiment or the fourth embodiment, but modified by an additional addition of 5 wt% quartz relative to the clay in one variant to increase the SiO2 content, and addition of relative 5 wt% of a carbonate (e.g. calcite and / or dolomite mixture) in another variant to increase the relative proportion of the carbonate content.

[0081] The enlarged images in Fig. 6 of particles of the second component (the clay-based xerogel) clearly show the agglomerated structure of the particles consisting of very fine particles.

[0082] The binders according to the invention with the clay-based xerogel also achieve remarkable results in use, as can be seen from the concrete data presented below. For this purpose, a binder composition as in the first exemplary embodiment was used, with a clay-based xerogel produced from a starting material according to the first exemplary embodiment and having a SAhs of 99 (120) for the following example values. In concrete tests, values ​​of FM [M-percent] of 1.3 (1.1), a5 [mm] of 520 (520), a density [kg / dm 3] of 2.37 (2.35) and an LP content [V percent] of 1.9 (2.0). A strength development in [MPa] of 11.8 (11.6) was achieved after one day, 19.4 (22.9) after two days, 36.9 (49.5) after seven days, and 49.6 (65.3) after 28 days. The invention thus enables novel cements and concretes with satisfactory concrete properties, in particular strengths, even when using the clay-based xerogel according to the invention as the main cement component.

[0083] The invention is not limited to the compositions and manufacturing parameters specifically and exemplarily presented in the embodiments. Rather, the individual features of the above description and the following claims, individually and in combination, represent the representation of the invention recognizable to a person skilled in the art for implementing the invention in its various embodiments.

Claims

Claims 1. Multi-component binder which is flowable and settable after addition of water and hardens to form strength-giving phases, with a first component containing clinker phases and a pozzolanic particulate second component, characterized in that the second component is in the form of secondary particles agglomerated from fine primary particles, BET-surface-reduced with a BET surface area of ​​in particular less than 32 m 2 / g, has an aluminum-containing silicate portion and a calcium-containing carbonate portion also present together in secondary particles, has an X-ray amorphous portion of at least 25% and / or a reaction heat development according to ASTM C 1897 / 20 of at least 150 J / g, and has bound water.

2. Binder according to claim 1, wherein the second component has an activity index SAI28 according to DIN EN 450-1 of at least 78%, and in particular the SAI28 measured in percent with the reaction heat development r measured in J / g in the relationship f r r+65 - t < SAI28 < fr r+65+t stands, with f r in the range [0.08; 0.14], in particular [0.1; 0.12] and t equal to 15, preferably equal to 10, in particular equal to 7, and / or with the amorphous fraction x measured in percent in the relationship f x x+65 - 1 < SAI28 < fx-x+65+t, with f x in the range [0.75; 0.85], in particular [0.78; 0.82] and t is 15, preferably 10, in particular 7.

3. Binder according to claim 1 or 2, in which the second component has a value of less than 1.2 g / 100 g in a methylene blue test, and in particular between the methylene blue value m measured in g / 100 g and the SAI28 measured in percent, the relationship f m-rn+104 - tm < SAI28 ^ fm m+104+tm applies, with f m in the range [-24; -16], in particular [-22; -18] and tm is 20, preferably 16, in particular 12.

4. Binder according to one of the preceding claims, in which the bound water correlates with a thermogravimetrically determined mass loss from 130°C to 400°C of at least 1%, preferably at least 2%, in particular at least 3%.

5. Binder according to one of the preceding claims, in which the mass loss w measured in percent is related to the SAI28 measured in percent in the relationship fw-w+70 - tw < SAI28 < fw w+70+tw, with f w in the area [5; 11], especially [7; 10] and tw is 15, preferably 12, in particular 10, and / or with the amorphous fraction x measured in percent in the relationship f xw x -0.9 - txw < w< f xw x -0.9+txw, with f xwin the range [0.05; 0.11], in particular [0.06; 0.1] and txw equal to 1.2, preferably equal to 0.

8.

6. Binder according to one of the preceding claims, in which the second component has a proportion of reactive SiC>2 according to DIN EN 197-1 of greater than 12%, preferably greater than 15%, in particular greater than 20%, in particular a proportion of reactive AI2O3 is at least 10%.

7. Binder according to claim 1, wherein the X-ray amorphous portion is an X-ray amorphous portion generated at least in part by an increase in the internal energy of the particles of the second component by means of mechanically induced energy input onto the silicate portion and the carbonate portion simultaneously at the same point of action.

8. Binder according to claim 7, wherein the exposure site comprises an achievable volume of at least 2000 l, preferably at least 4000 l, in particular at least 6000 l, of which at least 10%, preferably at least 15%, in particular at least 20% and / or at most 60%, further preferably at most 50%, in particular at most 40% is simultaneously accessible to the material experiencing the energy input.

9. Binder according to claim 7 or 8, wherein the exposure site is a site at which, in addition to the mechanically induced energy input, a fine grinding of the silicate portion and / or carbonate portion takes place starting from a starting material supplied to the exposure site, and in particular is an exposure site with an average residence time of the silicate portion and the carbonate portion which does not exceed one hour, preferably does not exceed 50 minutes, in particular does not exceed 40 minutes.

10. Binder according to one of claims 7 to 9, in which the exposure site is an exposure site under an atmosphere which is in particular in motion, and / or an exposure site under a temperature of not higher than 250°C, preferably not higher than 170°C, more preferably not higher than 140°C, in particular not higher than 120°C.

11. Binder according to one of claims 7 to 10, in which the silicate portion as well as the carbonate portion are portions originating from a starting material supplied to the site of action, and the starting material is at least partially and preferably predominantly consists of a clay material, in particular at least 25% by weight, preferably at least 35% by weight and particularly preferably at least 40% by weight of clay minerals including all amorphous constituents of the clay material belonging to the group of kaolinites, illites, smectites, chlorites, pyrophyllites or the vermiculite group, or mixtures thereof.

12. Binder according to one of claims 7 to 11, wherein the increase in internal energy is at least 50 J per gram of the material at the site of action, preferably more than 100 J / g, in particular more than 200 J / g.

13. Binder according to one of the preceding claims, in which the second component has a weight ratio of carbonate content calculated in [CO2] to a silicate content calculated in [SiO2] of at least 10%, preferably at least 20%, in particular at least 30% and / or at most 2, more preferably at most 1.5, in particular at most 1.

14. Binder according to claim 13, in which the ratio of carbonate content to silicate content is determined by an amount of a carbonate material added separately to the clay material of the starting material at least before the clay material reaches the point of action.

15. Binder according to one of claims 7 to 14, in which the place of action is the grinding chamber of a mill operated in continuous operation, in particular a stirred ball mill of in particular horizontal design, which has a power of at least 100 kW per m 3 Grinding chamber volume, preferably with a throughput of at least 60 kg per hour, and preferably with an energy supply of more than 200 kWh, but preferably also less than 1200 kWh per ton of treated material.

16. Binder according to one of the preceding claims, in which the first component is present in a weight proportion of at least 20%, in particular at least 30%, and the second component is present in a weight proportion of at least 5%, preferably of at least 10%, more preferably at least 15%, in particular of at least 20%.

17. Material usable as a cement constituent in the form of the second component of a multi-component binder according to one of the preceding claims.

18. Deposit comprising a quantity of not less than 2 tonnes, preferably not less than 4 tonnes, in particular not less than 10 tonnes of a material according to claim 17.

19. Concrete material with a multi-component binder according to one of claims 1 to 16.

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