Color optimization in the mechanochemical activation of clay

Abstract

The present invention relates to a method for mechanochemical activation and simultaneous color optimization of mineral materials, characterized in that the mechanochemical activation and simultaneous color optimization are performed in a first high-energy mill (40), and the mineral material is pulverized together with a solid reducing agent in the first high-energy mill (40).

Description

[Technical Field]

[0001] This invention relates to a method for optimizing color in the mechanochemical activation of clay. [Background technology]

[0002] Activated clay is well-established as an additive, particularly in the cement industry. Currently, the conventional method is the drying and firing of the clay, i.e., thermal activation. This requires energy for heating, and high temperatures can also cause undesirable changes in other materials.

[0003] Under firing conditions during thermal activation in an oxidizing atmosphere, naturally occurring iron compounds in clay are converted, particularly to red iron oxide. This results in a reddish coloration of activated clay, significantly reducing the market acceptance of cement produced in this manner. Iron content, or rather its strongly colored trivalent oxidation state (Fe 3+The iron content in fired clay greatly determines its color. Color is an important quality parameter for using these activated clays as components of cement, usually gray. Lower iron ("poor iron") clays can have an average Fe2O3 content of 2–9 wt%. In so-called "red clays," the Fe2O3 content can be up to 15–20%. During firing, these high iron content can result in a very severe and usually undesirable red discoloration of the artificial pozzolanes produced in this way and the composite cements made using them, while lower iron clays result in a pink color. For this reason, firing conditions, for example, with a reducing gas atmosphere are set in the firing or post-firing area of ​​a plant for the production of fired clay, in order to achieve the conversion of Fe2O3 to black magnetite Fe3O4, especially in red-colored minerals such as hematite. Similarly, setting reducing firing conditions requires easily combustible primary fossil fuels such as natural gas, crude oil, lignite, or hard coal, which are also expensive and CO2-intensive. Therefore, generating reduction firing conditions to alter the color is, in practice, contrary to the firing conditions for optimal fuel conversion. In particular, so-called secondary fuels require continuous oxidation firing conditions for effective firing, which in turn requires complex post-treatment of trivalent iron species to eliminate or reduce undesirable red coloration in the thermoactivated clay.

[0004] International Publication No. 2017 / 008863 discloses methods and plant equipment for processing and activating raw materials.

[0005] European Patent Application Publication No. 3 909 682 discloses a method and roller mill for thermomechanical activation of clay mixtures.

[0006] German Patent Application Publication No. 10 2015 106 109 discloses a method for the tribochemical activation of binders and additives.

[0007] A general overview of prior art can be found, for example, in the following scientific publications: Bolm,Carsten;Hernandez,Jose G.(2018):Mechanochemistry of Gaseous Reactants(Appl.Chem.Int.Ed.,58).http: / / dx.doi.org / 10.1002 / anie.201810902.

[0008] Fernandez,Rodrigo;Martirena,Fernando;Scrivener,Karen L.(2011):The origin of the pozzolanic activity of calcined clay minerals:A comparison between kaolinite,illite and montmorillonite.In:Cement and Concrete Research 2011(41), pp. 113-122.DOI:10.1016 / j.cemconres.2010.09.013.

[0009] Ilic, Biljana;Radonjanin,Vlastimir;Malesev,Mirjana;Zdujic,Miodrag;Mitrovic,Aleksandra(2016):Effects of mechanical and thermal activation on pozzolanic activity of kaolin containing mica.In:Applied Clay Science 2016(123), pp. 173-181.

[0010] Tole, Ilda; Habermehl-Cwirzen, Karin; Cwirzen, Andrzej (2019): Mechanochemical activation of natural clay minerals: an alternative to produce sustainable cementitious binders-review. In: Miner Petrol 2019(113), pp. 449-462. DOI: 10.1007 / s00710-019-00666-y.

[0011] Tole, Ilda;Habermehl-Cwirzen,Karin;Rajczakowska,Magdalena;Cwirzen,Andrzej(2018):Activation of a Raw Clay by Mechanochemical Process-Effects of Various Parameters on the Process Efficiency and Cementitious Properties.In:Materials(Basel,Switzerland)2018(11).DOI:10.3390 / ma11101860

[0012] German Patent Application Publication No. 10 2017 114 831 discloses a method for processing fly ash and a method for producing cement.

[0013] Chinese Patent No. 109954485 discloses a method for producing activated clay.

[0014] Czech Republic Patent No. 307528 discloses a method for processing kaolin, clay, or mixtures thereof.

[0015] Japanese Patent Publication No. 08-067803 discloses epoxy resin and its manufacturing method.

[0016] Chinese Patent No. 111 362 602 discloses a method for changing the color of a clay-containing cement material.

[0017] International Publication No. 97 / 01614 discloses clay activation with metal salts.

[0018] Russian Patent No. 2209824 discloses a method for producing slurry powder.

[0019] Internet URL: https: / / www.sciencedirect.com / science / article / pii / S0008884619311421 / pdfft?md5=d44e758bb1164f2d480c3a3ede769488&pid=1-s2.0-S0008884619311421-rnain.pdf [Discovered on 2024-05-13] SIMON BLOTEVOGEL: "Ability of the R3 test to evaluate differences in early age reactivity of 16 industrial ground granulated blast furnace slags (GGBS)", CEMENT AND CONCRETE RESEARCH., Vol.130, April 1, 2020 (2020-04-01), page 105998, XP93161349, US ISSN:0008-8846, DOI:10.1016 / j.cemconres.2020.105998 discloses the R3 trial.

[0020] TOLE ILDA ET AL: "Mechanochemical activation of natural clay minerals: an alternative for the production of sustainable cementitious binders - Review," MINERALOGY AND PETROLOGY, SPRINGER VIENNA, VIENNA, Vol. 113, No. 4, May 8, 2019 (2019-05-08), pages 449-462, XP036833323, ISSN: 0930-0708, DOI: 10.1007 / S00710-019-00666-Y [Discovered on May 8, 2019] discloses the mechanochemical activation of clay.

[0021] Since clay constitutes a complex system (especially when compared to the combustion of limestone), different activation methods result in different products (activated clay) with different properties. Similarly, the diversity of available clays means that not all methods can be used for all clays.

Prior Art Documents

Patent Documents

[0022] [[ID=...]] [[ID=...]]

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[0023] [Non-licensed Document 1] Bolm,Carsten;Hernandez,Jose G.(2018):Mechanochemistry of Gaseous Reactants(Appl.Chem.Int.Ed.,58).http: / / dx.doi.org / 10.1002 / anie.201810902 [Non-licensed Document 2] Fernandez, Rodrigo; Martirena, Fernando; Scrivener, Karen L. (2011): The origin of the pozzolanic activity of calcined clay minerals: A comparison between kaolinite, illite and montmorillonite. In: Cement and Concrete Research 2011(41),pp.113-122.DOI:10.1016 / j.cemconres.2010.09.013 [Non-licensed Document 3] Ilic,Biljana;Radonjanin,Vlastimir;Malesev,Mirjana;Zdujic,Miodrag;Mitrovic,Aleksandra(2016): Effects of mechanical and thermal activation on pozzolanic activity of kaolin containing mica.In:Applied Clay Science 2016(123),pp.173-181.DOI:10.1016 / j.clay.2016.01.029 [Non-Patent Document 4] Tole,Ilda;Habermehl-Cwirzen,Karin;Cwirzen,Andrzej(2019):Mechanochemical activation of natural clay minerals:an alternative to produce sustainable cementitious binders-review.In:Miner Petrol 2019(113),pp.449-462.DOI:10.1007 / s00710-019-00666-y [Non-Patent Document 5] Tole, Ilda;Habermehl-Cwirzen,Karin;Rajczakowska,Magdalena;Cwirzen,Andrzej(2018):Activation of a Raw Clay by Mechanochemical Process-Effects of Various Parameters on the Process Efficiency and Cementitious Properties.In:Materials(Basel,Switzerland)2018(11).DOI:10.3390 / ma11101860 [Non-Patent Document 6] https: / / www.sciencedirect.com / science / article / pii / S0008884619311421 / pdfft?md5=d44e758bb1164f2d480c3a3ede769488&pid=1-s2.0-S0008884619311421-rnain.pdf>[Discovered on 2024-05-13] SIMON BLOTEVOGEL: "Ability of the R3 test to evaluate differences in early age reactivity of 16 industrial ground granulated blast furnace slags (GGBS)", CEMENT AND CONCRETE RESEARCH., Vol.130, April 1, 2020 (2020-04-01), page 105998, XP93161349, US ISSN:0008-8846,DOI:10.1016 / j.cemconres.2020.105998 [Non-Patent Document 7] TOLE ILDA ET AL:"Mechanochemical activation of natural clay minerals:an alternative for the production of sustainable cementitious binders-Review,"MINERALOGY AND PETROLOGY,SPRINGER VIENNA,VIENNA,Vol.113,No.4,May 8,2019(2019-05-08),pages 449-462,XP036833323,ISSN:0930-0708,DOI:10.1007 / S00710-019-00666-Y[Discovered May 8, 2019] [Overview of the Initiative] [Problems that the invention aims to solve]

[0024] The objective of this invention is to enable color optimization in a simple manner, and therefore, in particular, to enable the use of clays with high iron content that would otherwise be unusable. [Means for solving the problem]

[0025] This objective is achieved by a method having the features disclosed in claim 1. Advantageous further embodiments arise from the dependent claims, the following description, and the drawings. [Modes for carrying out the invention]

[0026] The method according to the present invention is used for the mechanochemical activation and simultaneous color optimization of mineral materials. Therefore, the objective is, on the one hand, to mechanochemically activate the mineral material in a first high-energy mill rather than through a thermal process. On the other hand, the objective is to achieve color optimization simultaneously with activation, without performing this in subsequent steps, as is usually the case with thermal activation. Therefore, simultaneous activation and color optimization in a single grinding procedure, and thus in a single mechanical unit, is essential. Mechanochemical activation and simultaneous color optimization are performed in the first high-energy mill.

[0027] For this purpose, the mineral material is ground together with a solid reducing agent in a first high-energy mill.

[0028] Mechanochemical activation consists of three phases or stages: In the first stage, particle size decreases (almost linearly) with respect to energy input. Simply put, the more it is ground, the finer the product becomes (Rittinger zone). However, there is a limit to this; below this particle size, further progress is almost impossible. After this point, with further energy input (aggregation zone), a second stage is reached where the particle size does not change any further. In this stage, the crystalline structure is destroyed by loosening of atomic bonds; individual atoms or entire groups of atoms are replaced by other atoms or other groups of atoms. Especially at the particle surface, high energy transfer and subsequent chemical reactions alter the initial crystalline structure, bond type, and oxidation state of atoms. Therefore, for economic reasons, the transition from the first to the second stage is avoided during normal grinding, where only surface formation is achieved. However, this process is necessary for mechanochemical activation. Further increasing the energy input can reach a third stage (aggregation zone) where an increase in particle size due to the aggregation of nanoparticles can be observed, which has a positive effect on the workability of activated clay-based cement in mortar and concrete. Therefore, it is much more likely that this zone can be avoided during normal grinding, as better results in terms of particle size distribution can be achieved at a lower cost.

[0029] However, it has been found that high energy input, i.e., in the second stage, brings about a change in the material itself, and in the case of clay, it brings about activation, i.e., reactivity that makes it possible to use the material as a binder component (and therefore as a clinker substitute), similar to thermal activation. Therefore, with such high energy input, it is possible to omit the subsequent heat treatment.

[0030] However, in this case, it has been found that the energy requirements for purely mechanochemical activation can be higher than those for thermal activation. Therefore, the method according to the present invention initially appears to be at a disadvantage compared to conventional thermal activation. However, perhaps despite the relatively high energy requirements, the method according to the present invention has been found to be advantageous, particularly for the activation of clay. Thermal activation usually has several drawbacks, especially for complex starting materials such as clay. On the one hand, for example, substances in gaseous form can escape from the clay at high temperatures, which is known to require more expensive exhaust gas purification, particularly with additional CO2 sequestration (carbon capture) that may be needed in the future. This can be avoided by not using higher temperatures. On the other hand, coloring components such as iron compounds are often oxidized at high activation temperatures, and in the case of iron, this results in the undesirable red coloration of the product. In contrast, co-grinding with a solid reducing agent makes it possible to use already strongly colored materials, particularly those containing Fe2O3, such as clay known as "red clay," as starting materials and even process them into color-neutral products. This increases the energy requirements of the actual activation process in the method according to the present invention, but it simplifies the exhaust gas treatment and avoids a separate process with subsequent reductions. Therefore, the entire activation procedure for producing marketable binders can be simplified in an efficient manner. Furthermore, different clay minerals have different optimal activation temperatures. For example, minerals of the kaolin and chlorite groups are activated at significantly lower temperatures than minerals of the mica group (muscovite, illite, etc.). If the optimal activation temperature of kaolinite is selected for the thermal activation of clay containing minerals from these groups, minerals such as muscovite and illite remain unactivated. However, if the significantly higher activation temperatures of muscovite and illite are selected for thermal activation, the formation of new mineral phases, particularly spinel, leads to excessive combustion of kaolinite, resulting in deactivation. However, this distinction of clay minerals regarding optimal activation temperatures is eliminated by mechanochemical activation.

[0031] Coloring components such as iron compounds are often oxidized at higher activation temperatures, and in the case of iron, this leads to an undesirable increase in the red coloration of the product. In contrast to the thermal activation of clay, in which the clay mineral is dehydroxylated and the resulting water completely escapes, the mechanochemical method according to the present invention demonstrates that the water and hydroxyl groups of the clay mineral are retained in the mineral structure and become available for reaction with solid metals such as aluminum powder or zinc powder. The hydrogen produced during this reaction enables the conversion of Fe2O3 to Fe3O4 in the clay mineral, in particular, according to the following chemical reaction. 2 Al + 3 H2O → Al2O3 + 3 H2 9 Fe2O3 + 3 H2 → 6 Fe3O4 + 3 H2O Total: 2 Al + 9 Fe2O3 → Al2O3 + 6 Fe3O4

[0032] As can be seen from the reaction equation, this is an autocatalytic reaction. This means that the water required for the first reaction step is not completely consumed.

[0033] According to the present invention, the kinetics of the chemical reduction reaction from Fe2O3 to Fe3O4 are improved by the availability of water molecules or hydroxyl groups required for the reduction reaction in the clay mineral, making the color optimization method particularly efficient. This effect is based on the high energy level during mechanochemical activation and the resulting surface chemistry. However, after thermal activation, the water or hydroxyl groups required for such conversion are absent. The strong mixing effect of the materials during mechanochemical activation is due to the high speed of the agitator in the first high-energy mill.

[0034] According to the present invention, the mechanochemical activation of the mineral material causes an increase in the R3 value (7d), determined for the evaluation of reactivity or pozzolanic properties according to ASTM C1897-20, by at least 150 J / g, preferably at least 250 J / g, compared to the starting material. Therefore, the activation is high enough to allow the activated material to be used as an auxiliary cementitious material (SCM). The ASTM C1897-20 standard is a standard commonly used in the cement industry to test the reactivity of cement additives and characterize their setting behavior.

[0035] In a further embodiment of the present invention, grinding and mechanochemical activation are performed at a minimum of 100 kW / m². 3 Preferably at least 200 kW / m 3 This is done by the energy input per unit volume of the grinding chamber. A typical value for a ball mill, as an example of an ultrafine mill, is usually 20 kW / m³. 3 It is close to and therefore remarkably low (and energy efficient). In this regard, the grinding chamber volume is understood to be the grinding chamber volume available within the first high-energy mill, i.e., the free volume when there is no material in the first high-energy mill, for example, no balls. Therefore, components belonging to the mill, such as shafts that are movable inside, are not part of the grinding chamber volume because this volume cannot be occupied by material.

[0036] In a further embodiment of the present invention, size-selective separation into coarse and fine fractions is performed after grinding. The fine fraction is returned to a first high-energy mill, and the coarse fraction is removed as a product. The separation is performed, for example, using a separator. In this case, the fine fraction is returned because activation is associated with an increase in particle size. This is fundamentally different from conventional separation and recirculation in mills where the coarse fraction is usually recirculated.

[0037] In a further embodiment of the present invention, the second size-selective separation is performed such that the size boundary between the second coarse fraction and the second fine fraction corresponds to the smallest particle size achievable with a second high-energy mill multiplied by 2.

[0038] In a further embodiment of the present invention, the first high-energy mill is operated continuously. This means that mineral material is continuously supplied to the first high-energy mill, and at the same time, activated mineral material is continuously removed. Therefore, preferably, the first high-energy mill operates as a continuous mill having an input side and an output side.

[0039] In further embodiments of the present invention, the first high-energy mill is selected from the group including vibratory mills, planetary ball mills, and agitator bead mills. Preferably, the first high-energy mill is selected from the group including planetary ball mills and agitator bead mills. These types of mills have been proven particularly suitable for mechanochemical activation because they can achieve particularly high energy densities. A dry agitator bead mill is particularly preferred as the first high-energy mill.

[0040] In a further embodiment of the present invention, an agitator bead mill having a length-to-diameter ratio of 2.5:5 is selected.

[0041] In a further embodiment of the present invention, the first high-energy mill is filled with a grinding medium packing level of 50% to 95% volume, preferably 60% to 70% volume. Here, the bulk volume of the grinding medium is related to the volume of the first high-energy mill. The packing level is about 64% for simple packing and only about 74% for the densest ball packing, so even a theoretical grinding medium packing level of 100% leaves a corresponding empty space that can be occupied, for example, by the mineral material to be activated. However, since the packing level of the grinding medium packing is highly dependent on the shape and uniformity of the grinding medium, it is simpler from a practical standpoint to relate the grinding medium packing level to the bulk volume rather than the actual (filled) volume.

[0042] In further embodiments of the present invention, a grinding medium made of iron or an iron alloy, or a grinding medium made of aluminum or an aluminum alloy is selected. Preferably, a grinding medium made of iron or an iron alloy is selected. In particular, a grinding medium made of steel is selected.

[0043] In further embodiments of the present invention, a ceramic grinding medium is selected.

[0044] In a further embodiment of the present invention, a grinding medium having a diameter of 1 mm to 10 mm is selected.

[0045] In a further embodiment of the present invention, the agitator bead mill is operated at a peripheral speed of 2 m / s to 6 m / s, preferably 3 m / s to 5 m / s, and particularly preferably 3.5 m / s to 4.5 m / s.

[0046] In a further embodiment of the present invention, the agitator bead mill operates with gas volume flow and material flow. The ratio of gas volume flow to material flow is 0.0001 m 3 / kg~5m 3 / kg, preferably 0.1m 3 / kg~2m 3 It is set to be / kg.

[0047] In a further embodiment of the present invention, the mineral material is dried and ground to a residual moisture content of less than 1% by weight and a particle size of less than 2 mm before being introduced into the first high-energy mill.

[0048] In further embodiments of the present invention, the mineral material is selected from the group comprising clay, ash, particularly fly ash, lime cement clinker, spent concrete fine powder, slag, silicate sheets, and silicate skeletons. Particularly preferred mineral materials are clay or a mixture of clay and one or more additional materials selected from the group comprising ash, particularly fly ash, fine cement clinker, spent concrete fine powder, slag, silicate sheets, silicate skeletons, and limestone.

[0049] In further embodiments of the present invention, the mineral material is mechanically activated with 0.1 to 50% by weight of quartz or corundum.

[0050] In further embodiments of the present invention, the material is analyzed after activation and color optimization to determine the activation. For the analysis, one or more methods are selected from the group including IR spectroscopy, RAMAN spectroscopy, X-ray diffraction analysis, thermal-fluctocalorimetry, thermogravimetric analysis, scanning electron microscopy, particle size and / or particle shape analysis, NMR spectroscopy, and color measurement. One or more methods selected from the group including IR spectroscopy, RAMAN spectroscopy, X-ray diffraction analysis, thermal-fluctocalorimetry, and color measurement are particularly preferred for the analysis.

[0051] In further embodiments of the present invention, the gas selected and used for the gas flow through the first high-energy mill is a gas comprising one or more gases selected from the group comprising nitrogen, argon, carbon dioxide, water vapor, carbon monoxide, hydrogen, and hydrocarbons, particularly methane, ethane, propane, and butane. Particularly preferably, the gas comprises mainly nitrogen, carbon dioxide, or water vapor (more than 50% by volume). Particularly preferably, the gas comprises less than 1% by volume, preferably less than 0.1% by volume, of oxygen.

[0052] In further embodiments of the present invention, a metal having an electronegativity of less than 1.8, preferably less than 1.7, is selected as the reducing agent. This ensures reliable reduction of iron trivalent.

[0053] In a further embodiment of the present invention, a metal having a lower (more negative) normal potential than iron is selected as the reducing agent.

[0054] In a further embodiment of the present invention, a metal from the group comprising aluminum, zinc, magnesium, and calcium is selected as the reducing agent. These metals have proven to be suitable for various reasons. First, these elements are not harmful in the finished cement product and are usually present anyway. Second, these metals such as aluminum are readily and cheaply available. Furthermore, these metals are particularly suitable for the method according to the present invention.

[0055] In a further embodiment of the present invention, 0.01 to 1 mol of reducing agent is added per 1 kg of the mineral material added.

[0056] In a further embodiment of the present invention, the amount of the reducing agent is selected such that the electrons released by the oxidation of the metal correspond to 0.03 to 0.33 times the amount of Fe 3+ contained in the mineral material. Theoretically, it would be sufficient to convert 1 / 3 of all iron atoms to divalent iron to form magnetite. However, it has been shown that even 10% results in a decolorization that gives an acceptable product. This means that within this range, product optimization (from acceptable to optimal) can be achieved at a cost that depends on the target market (the lower, the cheaper).

[0057] In a further embodiment of the present invention, the reducing agent is added with a particle size of less than 100 μm. Preferably, the reducing agent is added with a particle size exceeding 0.1 μm.

[0058] In a further embodiment of the present invention, the reducing agent is added by abrasion of the grinding medium. For this purpose, a grinding medium made of aluminum is preferably used. This is preferable when the amount of reducing agent required is small, i.e., especially in the case of low-iron clay.

[0059] In further embodiments of the present invention, the reducing agent is selected from the group comprising tin(II) sulfate (ZnSO4), antimony trioxide (Sb2O3), iron(II) sulfate (FeSO4), iron(II) sulfate monohydrate (FeSO4·H2O), and iron(II) sulfate heptahydrate (FeSO4·7H2O). Particularly preferred, the reducing agent is selected from the group comprising tin(II) sulfate and antimony trioxide (Sb2O3).

[0060] In further embodiments of the present invention, elemental carbon from the group including coal, graphite, anthracite, carbon black, or petroleum coke is selected as a reducing agent in the presence of carbon dioxide.

[0061] In further embodiments of the present invention, elemental carbon from the group including coal, graphite, anthracite, carbon black, or petroleum coke is selected as a reducing agent in the presence of a carbonate from the group including dolomite, magnesite, calcite, aragonite, iron carbonate, or alkali carbonate.

[0062] In a further embodiment of the present invention, the method includes a control circuit that controls the amount of reducing agent added. Thus, the amount of reducing agent added is actively controlled. The Lab color value (also known as CIELAB or L*a*b*) of the activated material produced by this method is determined. In Lab color values, the lightness value L* is perpendicular to the color plane (a*, b*) and is standardized by EN ISO 11664-4 "Colorimetry -- Part 4: CIE 1976 L*a*b* color space". When the a* value exceeds 3, the amount of reducing agent added increases, and when the a* value falls below 1, the amount of reducing agent added decreases. This optimizes the product for market acceptance and minimizes the consumption of the reducing agent. Active control also allows for optimal adaptation to the normally fluctuating compositions of natural clays, for example.

[0063] In a further embodiment of the present invention, the method includes a control circuit that controls the amount of reducing agent added. Therefore, the amount of reducing agent added is actively controlled. The Lab color value (also known as CIELAB or L*a*b*) of the activated material produced by this method is determined. In Lab color values, the lightness value L* is perpendicular to the color plane (a*, b*) and is standardized by EN ISO 11664-4 "Colorimetry -- Part 4: CIE 1976 L*a*b* color space". (a*) 2 If the color index, determined as the square root of the sum of (a*) and (b*)2, is greater than 5, preferably greater than 10, the amount of reducing agent added increases. Therefore, (a*) 2 If the color index, determined as the square root of the sum of (b*)2, is less than 10, preferably less than 5, the amount of reducing agent added is reduced.

[0064] In further embodiments of the present invention, partial thermal activation is performed before mechanochemical activation. Preferably, the thermal activation is performed at a temperature below 600°C, particularly preferably below 500°C. For example, a temperature of 900°C is common for pure thermal activation. On the one hand, this saves energy and thus reduces the energy requirements for mechanochemical activation at least partially. On the other hand, the reduction in the maximum temperature also has further positive effects, such as reducing the thermoformation of nitrogen oxides or avoiding changes in undesirable products, such as color changes due to oxidation of coloring components.

[0065] In a further embodiment, the present invention relates to a binder manufactured according to the method of the present invention.

[0066] The method according to the present invention will be described in more detail below with reference to exemplary embodiments shown in the drawings. [Brief explanation of the drawing]

[0067] [Figure 1] A flowchart is shown.

[0068] A very schematic diagram of this method is shown in Figure 1. The clay is taken from clay store 10 as a mineral material for activation and color optimization. This is Fe 3+ The substance passes through a chemical analysis sensor 20 to determine its content. 3+ The content is sent to the control unit 70. The control unit 70 regulates the input of aluminum from the aluminum store 30 to the clay. The clay-aluminum mixture is transferred to the first high-energy mill 40, where it is pulverized and activated and color optimized in the process, i.e., simultaneously. The material coming out of the first high-energy mill 40 is inspected in a color analyzer 50, the L*a*b* color value is determined and sent to the control unit 70. The finished product is transferred to the product store 60.

[0069] Alternatively, instead of chemical analysis 20, a further color analysis corresponding to color analysis 50 can be used. Thus, it is possible to greatly simplify the procedure. The color value of clay is used, and Fe 3+ The content is assigned to the color value based on experience. Therefore, this method can be implemented without any other modifications. [Explanation of Symbols]

[0070] 10 Clay storage section 20 Chemical analysis 30 Aluminum storage section 40. First High-Energy Mill 50 color analysis 60 Product silos 70 Control Unit

Claims

1. A method for mechanochemical activation and simultaneous color optimization of a mineral material, wherein the mechanochemical activation and simultaneous color optimization are performed in a first high-energy mill, the mineral material is pulverized in the first high-energy mill together with a solid reducing agent, and the mechanochemical activation of the mineral material causes an increase of at least 150 J / g, preferably at least 250 J / g, in the R3 value (7d) according to ASTM C1897-20.

2. The method according to claim 1, wherein a metal having an electronegativity of less than 1.8 is selected as the solid reducing agent.

3. The method according to claim 1, wherein a metal having a normal potential lower (more negative) than iron is selected as the solid reducing agent.

4. The method according to claim 1, wherein a metal from the group including aluminum, zinc, magnesium, and calcium is selected as the solid reducing agent.

5. The method according to claim 1, wherein 0.01 to 1 mol of a solid reducing agent is added per 1 kg of mineral material to be added.

6. The amount of the solid reducing agent is such that the electrons released by the oxidation of the metal are contained in the mineral material Fe ３＋ The method according to claim 1, wherein the amount is selected to correspond to 0.03 to 0.33 times the amount of the present.

7. The method according to claim 1, wherein the solid reducing agent is added in a particle size of less than 100 μm.

8. The method according to claim 1, wherein the solid reducing agent is added by the abrasion of the grinding medium.

9. where the solid reducing agent is tin(II) sulfate (ZnSO ４ ), antimony trioxide (Sb ２ O ３ ), iron(II) sulfate (FeSO ４ ), iron(II) sulfate monohydrate (FeSO ４ ·H ２ O), and iron(II) sulfate heptahydrate (FeSO ４ ·7H ２ O), the method according to claim 1, selected from the group comprising

10. The method according to claim 1, wherein elemental carbon from the group including coal, graphite, anthracite, carbon black, or petroleum coke is selected as the solid reducing agent from the group including coal, graphite, anthracite, carbon black, or petroleum coke in the presence of carbon dioxide.

11. The method according to claim 1, wherein elemental carbon from the group including coal, graphite, anthracite, carbon black, or petroleum coke is selected as the solid reducing agent in the presence of a carbonate from the group including dolomite, magnesite, calcite, aragonite, iron carbonate, or alkali carbonate.

12. The method according to any one of claims 1 to 11, wherein the method comprises a control circuit, the amount of the solid reducing agent added is controlled, for example, the L*a*b* color value is determined from the activated material produced by the method, the amount of the solid reducing agent added is increased when the a* value exceeds 2, and the amount of the solid reducing agent added is decreased when the a* value falls below 1.

13. The method according to any one of claims 1 to 11, wherein partial thermal activation is performed before the mechanochemical activation.

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