Mechanochemically carbonated natural pozzolan, its preparation and use

Abstract

The present invention is applicable to a range of 0.5 to 50 m. 2 The present invention relates to a mechanically carbonated natural pozzolan having a specific surface area in the range of 0.1 to 1.5 μm / g. The present invention further relates to a method for producing the same and to its use, for example, as a filler or binder. The present invention further relates to compositions comprising a mechanically carbonated natural pozzolan and a further material selected from the group consisting of asphalt, cement, geopolymers, polymers, and combinations thereof, and methods for producing the same.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates to a mechanically carbonated natural pozzolan. The invention further relates to a method for producing the same and to its use, for example as a filler or binder. The invention further relates to compositions comprising the mechanically carbonated natural pozzolan and a further material selected from the group consisting of asphalt, cement, geopolymers, polymers, and combinations thereof, and methods for producing the same. [Background technology]

[0002] Background technology Concrete is a composite material containing a matrix of aggregate (typically rock material) and a binder (typically Portland cement or asphalt) that holds the matrix together. Concrete is the most frequently used building material and is said to be the second most widely used material on Earth after water.

[0003] In order to reduce the cost of concrete and the CO2 emissions generated by cement production worldwide, much research effort has been devoted to identifying inexpensive materials that can be used as fillers or alternative binders to replace binder components without adversely affecting the properties of concrete. Such secondary cementitious materials are an area of ​​widespread industrial interest.

[0004] An example of a widely used cement filler is limestone. For a comprehensive overview of fillers in cementitious materials, see John, Vanderley M., et al. "Fillers in cementitious materials—Experience, recent advances and future potential." Cement and Concrete Research 114 (2018): 65-78.

[0005] Portland cement production contributes approximately 8% of global carbon dioxide emissions. According to Vanderley et al., traditional mitigation strategies for CO2 emissions in the cement industry are not sufficient to ensure the necessary mitigation in a scenario of increasing cement demand. Currently, cement production is increasing due to a combination of increasing urbanization and the replacement of old infrastructure. Therefore, cement industry leaders consider the adoption of carbon capture and storage (CCS) an inevitable solution, despite its high cost and environmental risks. Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, there remains a need to develop affordable filler technologies that can combine both CO2 emission reductions through reduced cement production and CO2 emission reductions through carbon capture technologies, without adversely affecting the properties of concrete.

[0007] It is an object of the present invention to provide an improved filler for cement or asphalt binders.

[0008] It is a further object of the present invention to provide an improved filler for cement, geopolymer, or asphalt binder that is inexpensive to manufacture.

[0009] It is a further object of the present invention to provide an improved filler for cement, geopolymer, or asphalt binder that is produced using CO2 storage technology.

[0010] It is a further object of the present invention to provide an improved filler for cement, geopolymer, or asphalt binder that improves the compressive strength, strength activity index, and / or water demand properties of the resulting concrete. [Means for solving the problem]

[0011] Summary of the Invention In the first aspect, the present invention preferably provides a method for manufacturing a semiconductor device having a thickness of 0.05 to 50 m. 2 providing a mechanochemically carbonated natural pozzolan having a specific surface area in the range of 0.15 to 0.15 g / g, preferably obtainable by carbonation of a natural pozzolan precursor; the ratio of the total content of mechanochemically carbonated natural pozzolana to the total content of natural pozzolana precursors is at least 1.5:1, preferably at least 2:1, more preferably at least 2.5:1; and / or The ratio of the CO2 content of the mechanochemically carbonated natural pozzolan to the CO2 content of the natural pozzolan precursor is at least 1.1:1, preferably at least 1.3:1, and more preferably at least 1.4:1, where the CO2 content is measured by TGA using a temperature track as mass loss above 450°C, where the temperature is increased from room temperature to 800°C at a rate of 10°C / min.

[0012] EP 3744700B1 relates to the carbonation of recycled concrete fines, which are not natural pozzolans.

[0013] VIZCAYNO C ET AL: "Pozzolan obtained by mechanochemical and thermal treatments of kaolin," APPLIED CLAY SCIENCE, ELSEVIER, AMSTERDAM, NL, vol. 49 no. 4, (August 1, 2010, pp. 405-413), describes milling kaolin in an air atmosphere to increase its pozzolanic activity. As shown in the accompanying examples, the carbonated natural pozzolan of the present invention has surprisingly and significantly improved strength activity indices at 7 and 28 days compared to air-milled natural pozzolan.

[0014] In another aspect, the present invention provides a method for producing a mechanochemically carbonated natural pozzolan, said method comprising: a) providing a raw material comprising or consisting of a natural pozzolanic precursor; b) providing a gas comprising CO2, preferably comprising at least 0.5% CO2 by volume; c) introducing the raw material and the gas into a mechanical stirring unit; d) passing said raw material through a mechanical agitation operation in said mechanical agitation unit in the presence of said gas; The present invention provides a method comprising:

[0015] The raw material is a method for producing mechanochemically carbonated natural pozzolan, the method comprising: a) providing a solid raw material comprising or consisting of a natural pozzolan precursor; b) providing a gas comprising CO2, preferably comprising at least 0.5% CO2 by volume; c) introducing the solid raw material and the gas into a mechanical stirring unit; d) passing said solid raw material material through a mechanical stirring operation in said mechanical stirring unit in the presence of said gas to obtain said mechanochemically carbonated natural pozzolan; Preferably, the solid is used to provide a method comprising:

[0016] The method can be applied to various types of natural pozzolan precursors and advantageously results in unique mechanochemically carbonated natural pozzolans.

[0017] In another aspect, the present invention provides a mechanochemically carbonated natural pozzolan obtainable by the method for producing a mechanochemically carbonated natural pozzolan described herein.

[0018] As shown in the accompanying examples, it has been found that when such mechanochemically carbonated natural pozzolans described herein are used as fillers in cement, the compressive strength of the resulting concrete is surprisingly increased over that obtained for non-carbonated natural pozzolans, and in particular well above that of pure Portland cement. In particular, the setting time for strength development is significantly improved (shortened) compared to when non-mechanochemically carbonated natural pozzolans are used as fillers. Furthermore, much larger amounts of the present mechanochemically carbonated natural pozzolans can be used as fillers while still providing acceptable or even improved concrete performance.

[0019] It has further been found that the durability of concrete produced with the mechanochemically carbonated natural pozzolan is significantly increased. Without wishing to be bound by any particular theory, the inventors believe this is due to improved hydration at the micro- and sub-microscale, reduced chloride permeability, reduced concrete porosity, and / or passivation of free lime. Furthermore, the increased oxygen content compared to the untreated precursor or raw material may result in better dispersion in polar solvents and better compatibility with materials containing epoxy or carboxyl functionality.

[0020] Furthermore, as shown in the accompanying examples, water demand is reduced compared to pure cement, as well as compared to cement filled with non-carbonated natural pozzolana. This is particularly surprising in view of the reduced particle size of mechanochemically carbonated natural pozzolana compared to non-carbonated natural pozzolana. A reduced particle size is generally associated with increased water demand. A reduced water demand compared to untreated raw materials or pure cement can contribute to improved properties such as workability, compressive strength, permeability, water resistance, durability, weathering resistance, drying shrinkage, and cracking potential. For these reasons, limiting and controlling the amount of water in concrete is important for both constructability and service life. The present invention therefore allows for better control of water demand. Without wishing to be bound by any theory, it is believed that the mechanochemical process of the present invention may result in an increased amorphous content when analyzed by XRD, where at least some crystalline domains that may be present in the raw materials are maintained through the internal structure in the form of microcrystalline matter present in a more generalized disordered structure. This disordered macrostructure therefore promotes higher reactivity and improves cement hydration.

[0021] Furthermore, production of mechanochemically carbonated natural pozzolans relies on inexpensive CO2 capture technology platforms that can be produced in an economically feasible manner and operate with dilute CO2 streams, for example, directly at the point-source exhaust of a combustion plant, so as to produce a filler that combines the CO2 emission reductions achieved through reduced cement production and those achieved through CO2 sequestration. Thus, the mechanochemically carbonated natural pozzolans of the present invention, and in particular the mechanochemically carbonated natural pozzolans of the present invention, combine distinct mechanical properties with cost-effective CO2 capture technology, making them excellent fillers for many applications.

[0022] In another aspect, the present invention provides a composition comprising a mechanochemically carbonated natural pozzolan as described herein and an additional material selected from the group consisting of asphalt, cement, geopolymer, polymer, and combinations thereof.

[0023] In another aspect, the present invention provides a method for preparing a composition described herein, said method comprising: (i) providing a mechanochemically carbonated natural pozzolan as described herein; (ii) providing a further material selected from the group consisting of asphalt, cement, geopolymer, polymer, and combinations thereof; (iii) combining the mechanochemically carbonated natural pozzolan of step (i) with the material of step (ii); The present invention provides a method comprising:

[0024] In another aspect, the present invention is a method for preparing concrete or mortar, said method comprising: (i) providing a mechanochemically carbonated natural pozzolan as described herein and, optionally, a further material selected from the group consisting of asphalt, cement, geopolymer, and combinations thereof, in the form of a composition as described herein, wherein the further material is selected from the group consisting of asphalt, cement, geopolymer, and combinations thereof; (ii) providing a structural aggregate; (iii) contacting, preferably mixing, the mechanochemically carbonated natural pozzolan and further material of step (i) with the structural aggregate of step (ii) and, optionally, with water; The present invention provides a method comprising:

[0025] In another aspect, the present invention provides a concrete obtainable by the method for preparing a concrete described herein.

[0026] In another aspect, the present invention provides a method for producing a pozzolana comprising the steps of: as a filler, preferably in a material selected from the group consisting of asphalt, geopolymers, cement, mortar, polymers, and combinations thereof; As a partial replacement for asphalt, geopolymers, or cement in concrete or mortar, To increase the compressive strength of concrete or mortar, To improve the durability of concrete or mortar, To reduce the expansion of concrete, To improve the durability of concrete or mortar by reducing chloride permeability and / or porosity, To improve the strength activity index of concrete or mortar, and / or To reduce the water demand of concrete or mortar, Preferably, Incidentally, to improve the strength activity index of concrete and reduce the water demand of concrete, or Concomitantly, to improve the strength activity index of the mortar and reduce the water demand of the mortar. Provide use. DETAILED DESCRIPTION OF THE INVENTION

[0027] Description of the embodiment As used herein, the word "comprise" and variations thereof, such as "comprises" and "comprising," are to be interpreted in an open, inclusive sense, meaning that the described embodiments include the recited features, but do not exclude the presence of other features unless doing so would render the embodiment inoperable.

[0028] As used herein, the terms "one embodiment," "particular embodiment," "embodiment," and the like should be interpreted to mean that a particular feature, structure, or feature described in connection with an embodiment is included in at least one embodiment. Thus, the appearances of such terms in various places throughout this specification do not necessarily all refer to the same embodiment. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. For example, certain features of the present disclosure that are described herein in the context of individual embodiments are also expressly contemplated in combination in a single embodiment.

[0029] As used herein, the singular forms "a," "an," and "the" should be construed to include plural references unless the context clearly dictates otherwise. It should also be noted that the term "or" is generally used in its broadest sense, i.e., meaning "and / or," unless the context clearly dictates otherwise.

[0030] Throughout this specification, whenever a compound is referred to as a salt, this should be taken to include the anhydrous form of the compound as well as any solvates (particularly hydrates).

[0031] The term "mechanochemically carbonated natural pozzolan" is used herein to mean a natural pozzolan obtainable by the mechanochemical carbonation method of the present invention.

[0032] In accordance with the present invention, BET surface areas referred to herein are measured at a temperature of 77 K using a sample mass of 0.1 to 0.5 g. BET surface areas referred to herein are measured using nitrogen. A preferred analytical method for measuring BET surface area involves heating the sample to 400°C for a desorption cycle prior to surface area analysis. A suitable, and therefore preferred, analytical instrument for measuring BET surface area is a Micromeritics Gemini VII 2390 surface analyzer, preferably equipped with a Micromeritics FlowPrep 060 flow gas degassing unit.

[0033] As used herein, TGA refers to thermogravimetric analysis, a technique known to those skilled in the art. In the context of the present invention, a preferred TGA setup for measuring the CO2 content of raw and carbonated materials is a Setaram TAG 16 TGA / DSC dual chamber balance, using 0.1-2 mg samples. In accordance with the present invention, TGA is performed under an inert atmosphere, such as nitrogen or argon.

[0034] According to the present invention, particle size distribution characteristics referred to herein, such as D10, D50, and D90, as well as specific surface area (except when explicitly referred to as BET surface area), are measured using a light scattering particle size analyzer that utilizes the Fraunhofer theory of light scattering, such as a Brookhaven Laser Particle Sizer, Model Microbrook 2000LD, or another instrument of equal or better sensitivity, and report the data using a volume-equivalent sphere model. As known to those skilled in the art, D50 is the mass median diameter, i.e., the diameter at which 50% of the sample's mass is made up of smaller particles. Similarly, D10 and D90 represent the diameter at which 10% or 90% of the sample's mass is made up of smaller particles.

[0035] The total carbon (TC) content referred to herein is preferably measured according to the method described in Soil Sampling and Methods of Analysis, 2nd Ed., CRC Press (2008) (page 244), further incorporated herein by reference. The total carbon (TC) content is always expressed herein as % by weight based on the total weight of the composition being measured, i.e., based on the total weight of the clay precursor or based on the total weight of the carbonated clay.

[0036] In accordance with the present invention, the compressive strength, strength activity index, and water demand referred to herein are measured in accordance with ASTM C311 / C311M-22.

[0037] For the purposes of this disclosure, the ideal gas law is assumed such that the volume percent of a gas is considered to be equal to the mole percent.

[0038] Mechanochemically carbonated natural pozzolans In the first aspect, the present invention preferably provides a method for manufacturing a semiconductor device having a thickness of 0.05 to 50 m. 2 The mechanochemically carbonated natural pozzolan material has a specific surface area in the range of 0.15 to 0.15 g / g. The mechanochemically carbonated natural pozzolan material is obtainable by carbonation of a natural pozzolan precursor.

[0039] The mechanochemically carbonated natural pozzolan preferably has a CO2 content of greater than 0.5 wt. % (by total weight of the mechanochemically carbonated natural pozzolan), preferably greater than 0.6 wt. % (by total weight of the mechanochemically carbonated natural pozzolan), more preferably greater than 0.7 wt. % (by total weight of the mechanochemically carbonated natural pozzolan), where the CO2 content is measured as mass loss above 450°C by TGA-MS using a temperature trajectory where the temperature is increased from room temperature to 800°C at a rate of 10°C / min and then decreased to room temperature at a rate of 10°C / min.

[0040] In a preferred embodiment of the present invention, the mechanochemically carbonated natural pozzolan meets the strength requirements set forth in ASTM C618-12a (2012) and CSA A3001-18 (2018).

[0041] In an embodiment of the invention, the mechanochemically carbonated natural pozzolan has a viscosity of at least 0.2 m 2 / g, preferably at least 0.5m 2 / g, more preferably at least 0.7m 2 / g specific surface area.

[0042] In a preferred embodiment of the present invention, the mechanochemically carbonated natural pozzolan is 2 / g, preferably less than 30m 2 / g, more preferably less than 10m 2 / g. For example, the specific surface area is less than 50 m 2 / g, less than 48m 2 / g, less than 46m 2 / g, less than 44m 2 / g, less than 42m 2 / g, less than 40m 2 / g, less than 38m 2 / g or less, 36m 2 / g, less than 34m 2 / g, less than 32m 2 / g or less, 30m 2 / g, less than 28m 2 / g or less, 26m 2 / g or less, 24m 2 / g or less, 22m 2 / g or less, 20m 2 / g or less, 18m 2 / g or less, 16m 2 / g or less, 14m 2 / g or less, 12m 2 / g, less than 10m 2 / g or less, 8m 2 / g or less, 6m 2 / g or less.

[0043] In a highly preferred embodiment, the mechanochemically carbonated natural pozzolan is 2 / g, preferably less than 3m 2 / g, more preferably less than 2m 2 For example, mechanochemically carbonated natural pozzolans have a specific surface area of ​​less than 5.0 m 2 / g, less than 4.5m 2 / g, less than 4.0m 2 / g, less than 3.5m 2 / g or less, 3.0m 2 / g or less, 2.5m 2 / g or less, 2.0m 2 / g or less, 1.5m 2 / g or less.

[0044] The inventors have observed that mechanochemically carbonated natural pozzolans having a specific surface area within the ranges specified herein have particular properties when considering performance, handling, etc., compared to their untreated precursors, or even carbonated materials with other surface areas. Thus, in accordance with a highly preferred embodiment of the present invention, the mechanochemically carbonated natural pozzolans have a specific surface area of ​​0.2 to 50 m 2 / g, preferably 0.5 to 30m 2 / g, more preferably 0.7 to 10m 2 / g specific surface area, e.g., 0.7 to 50 m 2 / g, preferably 0.7 to 30m 2 / g, more preferably 0.7 to 10m 2 Specific surface area in the range of 0.7~5.0m / g 2 / g, preferably 0.7 to 3.0 m 2 / g, more preferably 0.7 to 2.0 m 2 Specific surface area in the range of 0.5~50m / g 2 / g, preferably 0.5 to 30m 2 / g, more preferably 0.5 to 10m 2 Specific surface area in the range of 0.5~5.0m / g 2 / g, preferably 0.5 to 3.0 m 2 / g, more preferably 0.5 to 2.0 m 2 / g range.

[0045] In an embodiment of the invention, the mechanochemically carbonated natural pozzolan has one, two or three, preferably three, of the following characteristics: D10 in the range of 0.005 to 10 μm, preferably 0.01 to 5 μm, most preferably 0.1 to 3 μm; D50 in the range of 0.1 to 50 μm, preferably 0.5 to 35 μm, most preferably 1 to 15 μm; D90 in the range of 0.5 to 300 μm, preferably 1 to 300 μm, most preferably 15 to 300 μm.

[0046] An embodiment of the invention provides a mechanochemically carbonated natural pozzolan as described herein, obtainable by concomitant carbonation and size reduction of a natural pozzolan precursor, wherein the ratio of the D50 of the carbonated natural pozzolan to the D50 of the natural pozzolan precursor is less than 0.5:1, preferably less than 0.1:1, more preferably less than 0.05:1. Preferably, the mechanochemically carbonated natural pozzolan is obtainable by carbonation of a natural pozzolan precursor, wherein the ratio of the total content of the mechanochemically carbonated natural pozzolan to the total content of the natural pozzolan precursor is at least 1.5:1, preferably at least 2:1, more preferably at least 2.5:1. Similarly, the mechanochemically carbonated natural pozzolan is preferably obtainable by carbonation of a natural pozzolan precursor, wherein the ratio of the CO2 content of the mechanochemically carbonated natural pozzolan to the CO2 content of the natural pozzolan precursor is at least 1.1:1, preferably at least 1.3:1, and more preferably at least 1.4:1, where the CO2 content is measured by TGA using a temperature trajectory as mass loss above 450°C, the temperature being increased at a rate of 10°C / min from room temperature to 800°C. The inventors have observed that methods in which the ratio is at least 1.5:1, preferably at least 2:1, and more preferably at least 2.5:1, gave even better results when the raw materials comprise volcanic ash, and are therefore preferred when the raw materials comprise volcanic ash.

[0047] In an embodiment of the present invention, the mechanochemically carbonated natural pozzolan has a total carbon content of at least 0.1% by weight, preferably at least 0.15% by weight, and more preferably at least 0.16% by weight. The inventors have observed that mechanochemically carbonated natural pozzolans (especially zeolites) having a total carbon content of at least 0.25% by weight, preferably at least 0.3% by weight, and more preferably at least 0.35% by weight, result in surprisingly large improvements in water demand. Thus, in a preferred embodiment, the mechanochemically carbonated natural pozzolan has a total carbon content of at least 0.25% by weight, preferably at least 0.3% by weight, and more preferably at least 0.35% by weight, and the natural pozzolan is preferably a zeolites.

[0048] Without wishing to be bound by any theory, the inventors believe that the increased specific surface area imparted by the dry mechanochemical carbonation method of another aspect of the invention (described elsewhere herein) is associated with the observed beneficial properties (such as superior strength activity index and reduced water demand), particularly when the natural pozzolan is volcanic ash. Accordingly, embodiments of the invention provide mechanochemically carbonated natural pozzolans as described herein, obtainable by concomitant carbonation and increased specific surface area of ​​a natural pozzolan precursor, wherein the ratio of the specific surface area of ​​the mechanochemically carbonated natural pozzolan to the specific surface area of ​​the natural pozzolan precursor is at least 1.2:1, preferably at least 1.4:1, and more preferably at least 1.6:1. A highly preferred embodiment of the present invention provides a mechanochemically carbonated natural pozzolan as described herein, obtainable by concomitant carbonation and increase in the specific surface area of ​​a natural pozzolan precursor, wherein the ratio of the specific surface area of ​​the mechanochemically carbonated natural pozzolan to the specific surface area of ​​the natural pozzolan precursor is at least 3.2:1, preferably at least 10:1, more preferably at least 20:1, and the natural pozzolan precursor is preferably volcanic ash.

[0049] Without wishing to be bound by any theory, the inventors believe that the increased BET surface area imparted by the dry mechanochemical carbonation process of another aspect of the invention (described elsewhere herein) is associated with the observed beneficial properties, such as superior strength activity index and reduced water demand. Accordingly, embodiments of the invention provide mechanochemically carbonated natural pozzolans as described herein, obtainable by concomitant carbonation and increased BET surface area of ​​natural pozzolan precursors, wherein the ratio of the BET surface area of ​​the mechanochemically carbonated natural pozzolan to the BET surface area of ​​the natural pozzolan precursor is at least 2:1, preferably at least 5:1, and more preferably at least 10:1.

[0050] Without wishing to be bound by any theory, the inventors believe that the increase in specific surface area imparted by the dry mechanochemical carbonation process of another aspect of the invention (described elsewhere herein) may significantly contribute to the observed increase in pore number due to the decrease in average pore width and increase in total pore surface area. Accordingly, embodiments of the invention provide a mechanochemically carbonated natural pozzolan obtainable by concomitant carbonation and increase in specific surface area of ​​a natural pozzolan precursor, wherein the BJH desorption cumulative surface area of ​​the pores of the mechanochemically carbonated natural pozzolan is at least 110%, preferably at least 120%, and more preferably at least 150% of the BJH desorption cumulative surface area of ​​the pores of the natural pozzolan precursor, and the desorption average pore width (BET 4V / A) of the mechanochemically carbonated natural pozzolan is 90% or less, preferably 85% or less, and more preferably 80% or less of the desorption average pore width (BET 4V / A) of the natural pozzolan precursor.

[0051] In the present invention, the mechanochemically carbonated natural pozzolan has a strength activity index (SAI) at 7 days that is at least 75%, preferably at least 80%. The inventors have observed that the mechanochemical process of the present invention makes it possible to obtain carbonated natural pozzolans with excellent 7-day SAI. Thus, in a highly preferred embodiment, the mechanochemically carbonated natural pozzolan has an SAI at 7 days that is at least 90%, preferably at least 98%, more preferably at least 120%.

[0052] In an embodiment of the invention, the mechanochemically carbonated natural pozzolan has a Strength Activity Index (SAI) at 28 days of at least 75%, preferably at least 80%, more preferably at least 85%. The inventors have observed that the mechanochemical process of the invention makes it possible to obtain carbonated natural pozzolans with excellent SAI at 28 days. Thus, in a highly preferred embodiment, the mechanochemically carbonated natural pozzolan has an SAI at 28 days of at least 100%, preferably at least 105%, more preferably at least 120%.

[0053] In an embodiment of the invention, the mechanochemically carbonated natural pozzolan has a water demand that is less than 98%, preferably less than 97.5%, more preferably less than 97%. The inventors have observed that the mechanochemical process of the invention makes it possible to obtain carbonated natural pozzolans with a water demand that is less than 94%, preferably less than 93%, more preferably less than 92%. In a highly preferred embodiment, the mechanochemically carbonated natural pozzolan has a water demand that is less than 91%, preferably less than 90%, more preferably less than 89%, and the natural pozzolan is preferably a zeolite.

[0054] Natural pozzolans include volcanic ash, volcanic rock, perlite, pumice, obsidian, slag, tuff (e.g., rhyolitic tuff, dacite tuff, basaltic tuff, trachytic tuff, sclerite tuff, digenetic lithoid tuff), andesite, clinoptiololite, heulandite, augite, apatite, titanite, biotite, lanthanum, sapphire, sodalite, magnetite, muscovite, chabazite, analcime, hematite, cristobalite, leucite, scoria, illite, mica, hornblende, mordenite, andesite, basalt, diatomite, tripoliticite, tuff, and opaline shale. Preferably, the mineral is selected from basalt, volcanic rock, perlite, and zeolite.

[0055] In a preferred embodiment of the invention, the natural pozzolan precursor comprises CaO and / or Ca(OH), preferably the natural pozzolan precursor comprises at least 0.1 wt. % (by total weight of the natural pozzolan precursor) of CaO and / or Ca(OH), preferably at least 0.5 wt. % (by total weight of the natural pozzolan precursor) of CaO and / or Ca(OH).

[0056] Method for producing mechanochemically carbonated natural pozzolan and mechanochemically carbonated natural pozzolan obtainable thereby Without wishing to be bound by any theory, the inventors believe that the dry mechanochemical carbonation process of the present invention imparts unique and desirable properties to the carbonated natural pozzolans obtainable by this process. For example, the unique surface area and pore properties imparted by the dry mechanochemical carbonation process of the present invention are believed to be important for achieving the material's surprising performance, for example, in concrete.

[0057] In a further aspect, the present invention provides a method for producing a mechanochemically carbonated natural pozzolan, said method comprising: a) providing a raw material comprising or consisting of a natural pozzolanic precursor; b) providing a gas comprising CO2, preferably comprising at least 0.5% CO2 by volume; c) introducing the raw material and the gas into a mechanical stirring unit; d) passing said raw material materials through a mechanical stirring operation in said mechanical stirring unit in the presence of said gas to obtain said mechanochemically carbonated natural pozzolan; The present invention provides a method comprising:

[0058] The raw material is a method for producing mechanochemically carbonated natural pozzolan, the method comprising: a) providing a solid raw material comprising or consisting of a natural pozzolan precursor; b) providing a gas comprising CO2, preferably comprising at least 0.5% CO2 by volume; c) introducing the solid raw material and the gas into a mechanical stirring unit; d) passing said solid raw material material through a mechanical stirring operation in said mechanical stirring unit in the presence of said gas to obtain said mechanochemically carbonated natural pozzolan; Preferably it is a solid raw material, so as to very preferably provide a method comprising:

[0059] Natural pozzolans include volcanic ash, volcanic rock, perlite, pumice, obsidian, slag, tuff (e.g., rhyolitic tuff, dacite tuff, basaltic tuff, trachytic tuff, sclerite tuff, digenetic lithoid tuff), andesite, clinoptiololite, heulandite, augite, apatite, titanite, biotite, lanthanum, sapphire, sodalite, magnetite, muscovite, chabazite, analcime, hematite, cristobalite, leucite, scoria, illite, mica, hornblende, mordenite, andesite, basalt, diatomite, tripoliticite, tuff, and opaline shale. Preferably, the mineral is selected from basalt, volcanic rock, perlite, and zeolite.

[0060] Natural pozzolans include volcanic ash, volcanic rock, perlite, pumice, obsidian, slag, tuff (e.g., rhyolitic tuff, dacite tuff, basaltic tuff, trachytic tuff, sclerite tuff, digenetic lithoid tuff), andesite, clinoptiololite, heulandite, augite, apatite, titanite, biotite, glaucoma, sapphire, sodalite, magnetite, muscovite, chabazite, analcime, hematite, cristobalite, leucite, illite, mica, hornblende, mordenite, andesite, basalt, diatomite, tripoliticite, tuff, and opaline shale. Preferably, the natural pozzolans are selected from the group consisting of augite, volcanic ash, volcanic rock, augite, apatite, titanite, nautilus, and sodalite. These preferred natural pozzolans have been found to be exceptionally susceptible to carbonation, which provides significant performance benefits when considered for use as a supplemental cementitious material in concrete.

[0061] Process Description The term "raw material" should be interpreted as a material consisting of or including a natural pozzolan precursor. The natural pozzolan can be mixed with other materials (e.g., fly ash) to form the raw material, or the natural pozzolan can consist essentially of the natural pozzolan. The term "precursor" is used to refer to the natural pozzolan before it is subjected to the mechanochemical carbonation of the present invention. However, it is preferred that the raw material consists essentially of the natural pozzolan precursor and, optionally, water, as this makes it possible to optimize the process conditions and achieve the desired properties of the carbonated natural pozzolan without having to consider the properties of other materials present in the raw material.

[0062] In view of the guidance provided in this disclosure, it is within the ability of one skilled in the art to adapt the relevant process parameters so as to obtain a mechanochemically carbonated natural pozzolan having the properties recited herein.

[0063] The gas provided in step (b) may be any gas stream containing CO2, such as normal air, a waste gas stream with a low CO2 concentration, or a concentrated CO2 stream.

[0064] In embodiments of the methods described herein, the gas provided in step (b) is ordinary air.

[0065] In a highly preferred embodiment of the method described herein, the gas provided in step (b) is combustion flue gas, in particular flue gas from fossil fuel combustion, wood pellet combustion, biomass combustion, or municipal waste combustion. The fossil fuel combustion may be coal, petroleum, petroleum coke, natural gas, shale oil, bitumen, tar sands oil, or heavy oil combustion, or any combination thereof. The combustion flue gas may optionally be treated to reduce its SO2 and / or NOx content.

[0066] The CO concentration of the gas provided in step (b) is preferably at least 0.1% by volume, more preferably at least 0.5% by volume. Typical CO concentrations in combustion flue gases are in the range of 1-15% by volume, for example 2-10% by volume, and it is preferred that the gas provided in step (b) has a CO concentration in the range of 1-15% by volume, for example 2-10% by volume. In alternative embodiments of the invention, the gas provided in step (b) comprises at least 80% by volume of CO, preferably at least 95% by volume. In some embodiments of the invention, the gas provided in step (b) comprises at least 80% by volume of CO, preferably at least 95% by volume of CO, and less than 1000 ppm (v / v) of HO, preferably less than 100 ppm (v / v) of HO. In some embodiments, the gas provided in step (b) comprises at least 0.1% by volume of CO and 5-25% by volume of HO. For example, in the case of flue gas, the gas provided in step (b) preferably comprises CO in the range of 1-15% by volume, such as 2-10% by volume, and 5-25% by volume, such as 15-20% by volume, of HO. The gas is typically not in a supercritical state, as this is not required for the mild mechanochemical carbonation process of the present invention. Therefore, in any embodiment of the present invention, it is highly preferred that the gas is not in a supercritical state.

[0067] Some embodiments of the invention provide the process described herein, with the proviso that the temperature and pressure during step (d) are such that the pressure is less than the saturated vapor pressure of water at the temperature in the mechanically stirred unit.

[0068] The phrase "in the presence of said gas" in step (d) should be interpreted to mean that the atmosphere inside the mechanically stirred unit consists essentially of the gas provided in step (b) at the start of step (d). It will be understood by those skilled in the art that the composition of the gas will change as the reaction progresses unless the reactor (mechanically stirred unit) is continuously purged or refilled.

[0069] Generally, step (d) can be carried out at atmospheric pressure, below atmospheric pressure, or above atmospheric pressure. Generally, step (d) is preferably carried out at atmospheric pressure or above atmospheric pressure. Accordingly, step (d) is preferably carried out at a pressure of at least about 100 kPa (e.g., at least 101.325 kPa). In a preferred embodiment of the present invention, step (d) is carried out at a pressure greater than about 300 kPa (e.g., 303.975 kPa), preferably about 600 kPa (e.g., 607.95 kPa). In an alternative embodiment of the present invention, step (d) is carried out at a pressure less than about 100 kPa (e.g., at least 101.325 kPa), such as less than 50 kPa or less than 10 kPa. It will be understood by those skilled in the art that the pressure of the gas (if not actively maintained) will vary as the reaction progresses. In these embodiments, it should be understood that the pressure within the mechanically agitated unit will be as specified herein when step (d) begins. In some embodiments, the pressure within the mechanically agitated unit will be as specified herein throughout step (d).

[0070] In highly preferred embodiments of the methods described herein, step (d) is carried out at a pressure below the critical pressure of carbon dioxide. Furthermore, the inventors have discovered that very high pressures are not required to prepare the carbonated glassy solids of the present invention, allowing the method to be carried out in a very energy-efficient manner. Accordingly, step (d) is preferably carried out at a pressure of less than 10,000 kPa, preferably less than 5,000 kPa, more preferably less than 2,500 kPa, and most preferably less than 1,000 kPa. It will be understood by those skilled in the art that the pressure of the gas (if not actively maintained) will vary as the reaction progresses. In these embodiments, it should be understood that the pressure within the mechanically agitated unit will be as specified herein at at least one point in time during step (d), e.g., when step (d) is initiated. In some embodiments, the pressure within the mechanically agitated unit will be as specified herein throughout most or nearly all of step (d).

[0071] In an embodiment of the invention, step (d) is carried out for at least 1 minute, preferably at least 30 minutes, such as at least 1 hour, at least 4 hours, or at least 8 hours.

[0072] In a preferred embodiment of the present invention, step (d) is substantially free of CO2 solubilizers, such as glycerin (propane-1,2,3-triol), which act to increase the solubility of carbon dioxide in aqueous solutions and allow for the formation of carbonate concentrations for sequestering carbon dioxide.

[0073] To stimulate carbonation, step (d) is carried out at a temperature below 150°C, preferably below 100°C, preferably below 90°C, more preferably below 80°C, and most preferably below 75°C. In a highly preferred embodiment of the invention, step (d) is carried out at a temperature in the range of 45-85°C, preferably 55-70°C. In a preferred embodiment of the invention, no active heating is applied, and therefore any increase in temperature is due to friction resulting from mechanical agitation or to exothermic reactions that occur during mechanochemical carbonation. The temperature is preferably measured on the solid material in the reactor (i.e., the mechanical agitation unit) during the process.

[0074] The low temperature requirements of the process mean that no fossil fuels are required, and electrical heating means (or low calorific value green fuel sources) can realistically be used to provide heat when the friction generated by mechanical agitation is insufficient to reach a desired temperature, such as above 45° C. In this way, fossil fuels can be avoided throughout the production chain.

[0075] As with any chemical process, the appropriate reaction time is highly dependent on the desired degree of carbonation, the desired surface area, as well as the applied pressure, temperature, and mechanical and chemical agitation, and can be readily determined by sampling the material and monitoring the reaction in the usual manner, for example, by BET analysis, particle size analysis, specific surface area, and total carbon content measurements as described herein.

[0076] The inventors have further discovered that the mechanochemical carbonation processes described herein can be advantageously carried out without the use of additional oxidizing agents, such as acids. Accordingly, the mechanochemical carbonation processes described herein are preferably carried out without the use of strong acids, and preferably without the use of any additional oxidizing agents other than the gas provided in step (b).

[0077] In a preferred embodiment of the present invention, the mechanical agitation operation in step (d) comprises grinding, milling, mixing, stirring (such as low-speed or high-speed stirring), shearing (such as high-torque shearing), shaking, blending, disintegrating, pulverizing, crushing, fine grinding, fluidized bed, or ultrasonic treatment, preferably grinding, milling, mixing, stirring (such as low-speed or high-speed stirring), shearing (such as high-torque shearing), or ultrasonic treatment. The inventors have discovered that the mechanochemical carbonation process is facilitated when the mechanochemical agitation operation in step (d) is carried out in the presence of grinding or milling media, preferably balls or beads. Preferred materials are stainless steel or aluminum oxide. In such a highly preferred embodiment, the mechanical agitation operation may simply be rotation of a mechanical agitation unit containing the solid raw materials, grinding or milling media, and gas. For example, grinding or milling media can be made from steel (e.g., AISI H13, modified H10), aluminum oxide, chrome white cast iron (e.g., ASTM A532), molybdenum steel (e.g., AISI M2, M4, M-42), chromium-based steel (e.g., H11, H12, H13 CPM V9, ZDP-189), or other media with a target HRC hardness of 60. Such grinding media can be utilized with or without surface treatments such as nitriding and carburizing. This can be conveniently performed in a rotating drum. It will be appreciated that the products obtainable by the process of the present invention when performed in a rotating drum can also be obtained using alternative grinding or milling techniques known to those skilled in the art.

[0078] In a preferred embodiment of the present invention, step (d) is carried out in the presence of a catalyst, preferably a metal oxide catalyst, such as a transition metal oxide catalyst. Examples of suitable catalysts are selected from the group consisting of iron oxide, cobalt oxide, ruthenium oxide, titanium oxide, nickel oxide, aluminum oxide, and combinations thereof.

[0079] Thus, as can be seen from the above, in a highly preferred embodiment of the present invention, step (d) comprises grinding, milling, mixing, stirring (such as slow or high speed stirring), shearing (such as high torque shear), shaking, blending, disintegrating, pulverizing, crushing, pulverizing, fluidized bed, or sonication, preferably grinding, milling, mixing, stirring (such as slow or high speed stirring), shearing (such as high torque shear), or sonication, in the presence of grinding or milling media, and a metal oxide catalyst.

[0080] The inventors have discovered that in terms of the efficiency of mechanochemical carbonation (e.g., reaction time, CO absorption, and particle size reduction), it is advantageous to use a medium as described hereinabove that includes (e.g., is coated with) the metal oxide catalyst on one or more surfaces that come into contact with the raw materials, and / or to use a mechanical agitation unit (or part thereof) that includes (or is coated with) the metal oxide catalyst, as described hereinabove. As explained elsewhere herein, the mechanical agitation operation may simply be the rotation of a mechanical agitation unit containing the raw materials or natural pozzolanic precursors for mechanochemical carbonation, grinding or milling media, metal oxide catalyst, and gas. This may conveniently be carried out in a rotating drum.

[0081] As will be clear from the description of the present invention, in a highly preferred embodiment, step (d) is a substantially dry process. While the presence of some moisture is acceptable and beneficial to carbonation efficiency, it is highly preferred that step (d) is not carried out with an aqueous solution or slurry. The inventors have discovered that carrying out step (d) on a solid greatly improves energy efficiency (since there is no need to subsequently remove water) and imparts unique properties to the resulting mechanochemically carbonated natural pozzolan, resulting in a material that is substantially different from, for example, aqueous carbonated materials. This is also reflected in its unique properties when used, for example, as a filler in concrete. In an embodiment of the present invention, the solid raw materials preferably have a water content of less than 30% by weight (by total weight of the solid raw materials), preferably less than 20% by weight.

[0082] According to a highly preferred embodiment of the present invention, the raw material provided in step (a) is a solid raw material. It is highly preferred that the solid raw material provided in step (a) has a moisture content of less than 30% by weight (based on the total weight of the solid raw materials), preferably less than 20% by weight, and more preferably less than 15% by weight. In terms of carbonation efficiency, it is preferred that the solid raw material have a moisture content of at least 2% by weight (based on the total weight of the solid raw materials), preferably at least 5% by weight, and more preferably at least 10% by weight. At a moisture content of less than 30% by weight (based on the total weight of the solid raw materials), the raw material still appears and behaves like a solid. In some embodiments of the present invention, the solid raw material may have a moisture content of less than 10% by weight (based on the total weight of the solid raw materials), less than 5% by weight, or less than 2% by weight. It is preferred that the solid raw material have a moisture content as specified herein at at least one point in time during step (d), for example, when starting step (d). In some embodiments, the moisture content of the raw material remains as specified herein throughout most or almost all of step (d).

[0083] Based on the guidance provided herein, it is within the routine ability of one of ordinary skill in the art to adjust the moisture content of the feedstock, such as before and / or during step (d), by, for example, spray-spraying the solid feedstock with an aqueous composition, such as water.

[0084] In other embodiments, the feedstock provided in step (a) is an aqueous slurry, solution, or suspension, e.g., an aqueous slurry. The aqueous slurry, solution, or suspension feedstock provided in step (a) may have a water content of greater than 50% by weight (by total weight of the aqueous slurry, solution, or suspension feedstock), e.g., greater than 70% by weight. The aqueous slurry, solution, or suspension feedstock preferably has a water content as specified herein at at least one point in time during step (d), e.g., when step (d) is initiated. In some embodiments, the water content of the aqueous slurry, solution, or suspension feedstock is as specified herein throughout most or nearly all of step (d).

[0085] In some embodiments, step (d) is followed by a dewatering step to reduce the moisture content of the resulting mechanochemically carbonated natural pozzolan.

[0086] In particular, the inventors have discovered that it is important to carry out step (d) so that a certain degree of carbonation, size reduction, and / or surface area increase is effective during step (d), i.e., during the combined carbonation and mechanical agitation. This results in a material that is significantly different from, for example, a material that is carbonated after being milled. To achieve these effects, it is preferred that step (a) of the present method comprises providing a solid raw material as described previously herein, and that step (d) is carried out on the solid raw material provided in step (a).

[0087] Therefore, in a highly preferred embodiment: the ratio of the total carbon content of the mechanochemically carbonated natural pozzolan obtained in step (d) to the total carbon content of the natural pozzolan precursor of step (a) is at least 1.5:1, preferably at least 2:1, more preferably at least 2.5:1; and preferably, the carbonation, size reduction, and / or surface area increase is carried out during step (d) so that the ratio of the CO content of the mechanochemically carbonated natural pozzolan obtained in step (d) to the CO content of the natural pozzolan precursor of step (a) is at least 1.1:1, preferably at least 1.3:1, more preferably at least 1.4:1, wherein the CO content is measured by TGA using a temperature track as mass loss above 450°C, the temperature being increased from room temperature to 800°C at a rate of 10°C / min.

[0088] As shown in the examples, certain materials have additional improved strength and / or water demand properties. Thus, in some preferred embodiments of the present invention, the method comprises: the ratio of the CO2 content of the mechanochemically carbonated natural pozzolan obtained in step (d) to the CO2 content of the natural pozzolan precursor of step (a) is at least 1.5:1, preferably at least 2:1, more preferably at least 2.5:1, the CO2 content being measured by TGA using a temperature track as mass loss above 450°C, the temperature being increased from room temperature to 800°C at a rate of 10°C / min; the ratio of D50 of the mechanochemically carbonated natural pozzolan obtained in step (d) to D50 of the natural pozzolan precursor of step (a) is less than 0.8:1, preferably less than 0.75:1, more preferably less than 0.5:1; the ratio of the specific surface area of ​​the mechanochemically carbonated natural pozzolan obtained in step (d) to the specific surface area of ​​the natural pozzolan precursor of step (a) is at least 2:1, preferably at least 3:1, more preferably at least 10:1; and wherein the natural pozzolan precursor is preferably volcanic ash.

[0089] Those skilled in the art will understand that when the material of step (a) is fed to step (d), it means that the carbonation, size reduction, and / or surface area described above occurs during step (d).

[0090] Without wishing to be bound by any theory, the inventors believe that the increased BET surface area imparted by the dry mechanochemical carbonation process is associated with the observed beneficial properties, such as superior strength activity index and reduced water demand. Thus, a highly preferred embodiment of the invention provides a process in which carbonation and increased BET surface area are carried out during step (d) such that the ratio of the BET surface area of ​​the mechanochemically carbonated natural pozzolan to the BET surface area of ​​the natural pozzolan precursor is at least 2:1, preferably at least 5:1, and more preferably at least 10:1.

[0091] In particularly preferred embodiments of the method of the present invention, the BJH desorption cumulative surface area of ​​the pores of the mechanochemically carbonated natural pozzolan obtained in step (d) is at least 110%, preferably at least 120%, more preferably at least 150% of the BJH desorption cumulative surface area of ​​the pores of the natural pozzolan precursor, and the desorption average pore width (BET 4V / A) of the mechanochemically carbonated natural pozzolan obtained in step (d) is at most 90%, preferably at most 85%, more preferably at most 80% of the desorption average pore width (BET 4V / A) of the natural pozzolan precursor.

[0092] In an embodiment of the invention, the methods described herein do not include a solid-liquid separation step after step (d) selected from filtration, decantation, and gravity separation (e.g., using a cyclone). Preferably, the methods of the invention do not include any solid-liquid separation step after step (d).

[0093] In an embodiment of the invention, the methods described herein do not include a size selection step, such as a screening or sieving step, after step (d).

[0094] Properties of natural pozzolanic precursors used in the mechanochemical carbonation process of the present invention In a preferred embodiment of the method described herein, the natural pozzolan precursor has a specific surface area of less than 20 m 2 / g, preferably less than 10 m 2 / g, more preferably less than 2 m 2 / g, and is a particulate solid material.

[0095] In a highly preferred embodiment of the present invention, the natural pozzolan precursor has one, two, or three, preferably three, of the following characteristics: · D10 within the range of 0.1 to 100 μm, preferably 0.1 to 75 μm, most preferably 0.1 to 50 μm; · D50 within the range of 5 to 200 μm, preferably 10 to 200 μm, most preferably 10 to 150 μm; · D90 within the range of 10 to 750 μm, preferably 20 to 500 μm, most preferably 40 to 300 μm.

[0096] In a preferred embodiment, the natural pozzolan precursor is selected from intermediate (containing 52 - 66 wt% SiO2), acidic (containing more than 66 wt% SiO2), basic (containing 45 - 52 wt% SiO2), or superbasic (containing less than 45 wt% SiO2) natural pozzolans.

[0097] While not wishing to be bound by any theory, it is believed that the presence of at least some alkaline earth metal oxides or hydroxides promotes carbonation. Thus, according to an embodiment or a preferred embodiment of the present invention, the natural pozzolan precursor has, in total, at least 0.01 wt%, preferably 0.05 wt%, of alkaline earth metal oxides and hydroxides as described herein. In a preferred embodiment of the present invention, the natural pozzolan precursor provided in step (a) contains CaO and / or Ca(OH)2, and preferably, the natural pozzolan precursor contains at least 0.1 wt% (based on the total weight of the natural pozzolan precursor) of CaO and / or Ca(OH)2, preferably at least 0.5 wt% (based on the total weight of the natural pozzolan precursor) of CaO and / or Ca(OH)2.

[0098] Properties of mechanochemically carbonated natural pozzolana obtained in step (d) In a preferred embodiment of the method for producing mechanochemically carbonated natural pozzolan described herein, the carbonated natural pozzolan obtained in step (d) has a pH of 0.05 to 50 ml. 2 The mechanochemically carbonated natural pozzolan obtained in step (d) preferably has a CO2 content of more than 0.5 wt. % (by total weight of the mechanochemically carbonated natural pozzolan), preferably more than 0.6 wt. % (by total weight of the mechanochemically carbonated natural pozzolan), more preferably more than 0.7 wt. % (by total weight of the mechanochemically carbonated natural pozzolan), the CO2 content being measured by TGA-MS using a temperature trajectory as mass loss above 450°C, the temperature being increased from room temperature to 800°C at a rate of 10°C / min and then decreased to room temperature at a rate of 10°C / min.

[0099] In a preferred embodiment of the method for producing mechanochemically carbonated natural pozzolan described herein, the carbonated natural pozzolan obtained in step (d) has a pH of 0.05 to 50 ml. 2 / g The mechanochemically carbonated natural pozzolan obtained in step (d) preferably has a CO2 content of more than 1 wt. % (by total weight of the mechanochemically carbonated natural pozzolan), preferably more than 2 wt. % (by total weight of the mechanochemically carbonated natural pozzolan), more preferably more than 3 wt. % (by total weight of the mechanochemically carbonated natural pozzolan), the CO2 content being measured by TGA-MS using a temperature trajectory as mass loss above 450°C, the temperature being increased from room temperature to 800°C at a rate of 10°C / min and then decreased to room temperature at a rate of 10°C / min.

[0100] In preferred embodiments of the present invention, the carbonated natural pozzolan obtained in step (d) meets the strength requirements set forth in ASTM C618-12a (2012) and CSA A3001-18 (2018). In certain embodiments, the methods described herein do not include a size selection step, such as a screening or sieving step, after step (d), and the carbonated natural pozzolan obtained in step (d) meets the strength requirements set forth in ASTM C618-12a (2012) and CSA A3001-18 (2018).

[0101] In an embodiment of the present invention, the mechanochemically carbonated natural pozzolan obtained in step (d) has a carbonation rate of at least 0.2 m 2 / g, preferably at least 0.5m 2 / g, more preferably at least 0.7m 2 / g specific surface area.

[0102] In a preferred embodiment of the present invention, the carbonated natural pozzolan obtained in step (d) is 2 / g, preferably less than 30m 2 / g, more preferably less than 10m 2 For example, the mechanochemically carbonated natural pozzolan obtained in step (d) has a specific surface area of ​​less than 50 m 2 / g, less than 48m 2 / g, less than 46m 2 / g, less than 44m 2 / g, less than 42m 2 / g, less than 40m 2 / g, less than 38m 2 / g or less, 36m 2 / g, less than 34m 2 / g, less than 32m 2 / g or less, 30m 2 / g, less than 28m 2 / g or less, 26m 2 / g or less, 24m 2 / g or less, 22m 2 / g or less, 20m 2 / g or less, 18m 2 / g or less, 16m 2 / g or less, 14m 2 / g or less, 12m2 / g, less than 10m 2 / g or less, 8m 2 / g or less, 6m 2 / g or less.

[0103] In a highly preferred embodiment, the carbonated natural pozzolan obtained in step (d) is 5 ml 2 / g, preferably less than 3m 2 / g, more preferably less than 2m 2 For example, mechanochemically carbonated natural pozzolans have a specific surface area of ​​less than 5.0 m 2 / g, less than 4.5m 2 / g, less than 4.0m 2 / g or less, 3.5m 2 / g or less, 3.0m 2 / g or less, 2.5m 2 / g or less, 2.0m 2 / g or less, 1.5m 2 / g or less.

[0104] The inventors have observed that mechanochemically carbonated natural pozzolans having a specific surface area within the ranges specified herein have particular properties when considering performance, handling, etc., compared to their untreated precursors, or even carbonated materials with other surface areas. Thus, according to a highly preferred embodiment of the present invention, the mechanochemically carbonated natural pozzolans obtained in step (d) have a specific surface area of ​​0.2 to 50 m 2 / g, preferably 0.5 to 30m 2 / g, more preferably 0.7 to 10m 2 / g specific surface area, e.g., 0.7 to 50 m 2 / g, preferably 0.7 to 30m 2 / g, more preferably 0.7 to 10m 2 Specific surface area in the range of 0.7~5.0m / g 2 / g, preferably 0.7 to 3.0 m 2 / g, more preferably 0.7 to 2.0 m 2 Specific surface area in the range of 0.5~50m / g 2 / g, preferably 0.5 to 30m 2 / g, more preferably 0.5 to 10m 2Specific surface area in the range of 0.5~5.0m / g 2 / g, preferably 0.5 to 3.0 m 2 / g, more preferably 0.5 to 2.0 m 2 / g range.

[0105] In an embodiment of the invention, the carbonated natural pozzolan obtained in step (d) has one, two or three, preferably three, of the following characteristics: D10 in the range of 0.005 to 10 μm, preferably 0.01 to 5 μm, most preferably 0.1 to 3 μm; D50 in the range of 0.1 to 50 μm, preferably 0.5 to 35 μm, most preferably 1 to 15 μm; D90 in the range of 0.5 to 300 μm, preferably 1 to 300 μm, most preferably 15 to 300 μm.

[0106] In an embodiment of the present invention, the mechanochemically carbonated natural pozzolan obtained in step (d) has a total carbon content of at least 0.1% by weight, preferably at least 0.15% by weight, and more preferably at least 0.16% by weight. The inventors have observed that mechanochemically carbonated natural pozzolans (especially zeolites) having a total carbon content of at least 0.25% by weight, preferably at least 0.3% by weight, and more preferably at least 0.35% by weight, provide surprisingly significant improvements in water demand. Thus, in a preferred embodiment, the mechanochemically carbonated natural pozzolan obtained in step (d) has a total carbon content of at least 0.25% by weight, preferably at least 0.3% by weight, and more preferably at least 0.35% by weight, providing even better results. Here, the mechanochemically carbonated natural pozzolan is preferably a zeolites.

[0107] According to the present invention, the mechanochemically carbonated natural pozzolan obtained in step (d) has a strength activity index (SAI) at 7 days of at least 75%, preferably at least 80%. The inventors have observed that the mechanochemical process of the present invention makes it possible to obtain carbonated natural pozzolans with excellent 7-day SAI. Thus, in a highly preferred embodiment, the mechanochemically carbonated natural pozzolan obtained in step (d) has an SAI at 7 days of at least 90%, preferably at least 98%, more preferably at least 120%.

[0108] In an embodiment of the invention, the mechanochemically carbonated natural pozzolan obtained in step (d) has a Strength Activity Index (SAI) at 28 days of at least 75%, preferably at least 80%, more preferably at least 85%. The inventors have observed that the mechanochemical process of the invention makes it possible to obtain carbonated natural pozzolans with excellent SAI at 28 days. Thus, in a highly preferred embodiment, the mechanochemically carbonated natural pozzolan obtained in step (d) has an SAI at 28 days of at least 100%, preferably at least 105%, more preferably at least 120%.

[0109] In an embodiment of the invention, the mechanochemically carbonated natural pozzolan obtained in step (d) has a water demand that is less than 98%, preferably less than 97.5%, more preferably less than 97%. The inventors have observed that the mechanochemical process of the invention makes it possible to obtain carbonated natural pozzolans with a water demand that is less than 94%, preferably less than 93%, more preferably less than 92%. In a highly preferred embodiment, the mechanochemically carbonated natural pozzolan obtained in step (d) has a water demand that is less than 91%, preferably less than 90%, more preferably less than 89%, and the natural pozzolan is preferably a zeolite.

[0110] Mechanochemically carbonated natural pozzolans obtainable by the methods described herein The inventors have discovered that the mechanochemical carbonation described herein imparts unique properties to the resulting mechanochemically carbonated natural pozzolan, resulting in a material that is substantially different from, for example, aqueously carbonated materials. This is reflected in its unique properties when used, for example, as a filler in concrete. In particular, the inventors have discovered that it is important to carry out step (d) so that a certain degree of carbonation, size reduction, and / or surface area increase is effective during step (d), i.e., during the combined carbonation and mechanical agitation. This results in a material that is significantly different from, for example, materials carbonated in an aqueous environment, or even materials carbonated after milling.

[0111] Thus, in another aspect, the present invention provides a mechanochemically carbonated natural pozzolan obtainable by the method for producing a mechanochemically carbonated natural pozzolan described herein.

[0112] As will be appreciated by those skilled in the art in view of the present disclosure, the mechanochemically carbonated natural pozzolans of the present invention combine unique mechanical properties with a cost-effective approach to CO sequestration, making them excellent fillers for many applications.

[0113] Compositions containing mechanochemically carbonated natural pozzolana and methods for preparing same Thus, in another aspect, the present invention provides a composition comprising a mechanochemically carbonated natural pozzolan as described herein and a further material selected from the group consisting of asphalt, cement, geopolymer, polymer, and combinations thereof, preferably cement, more preferably Portland cement.

[0114] In an embodiment, the further material is a polymer selected from thermoplastic polymers and thermosetting polymers. In a preferred embodiment, the further component is an epoxide resin, a phenol-formaldehyde resin, a polyalkylene terephthalate (preferably polyethylene terephthalate), a polyalkylene adipate terephthalate (preferably polybutylene adipate terephthalate), a polyalkylene isosorbide terephthalate (preferably polyethylene isosorbide terephthalate), a polyalkylene aromatic polyamide (preferably polyethylene aromatic polyamide), polyacrylonitrile, polyacetal, a polyimide, an aromatic polyester, or a polyisoprene (preferably cis-1,4-polyisoprene). , polyethylene, polypropylene, polyurethane, polyisocyanurate, polyamide, polyether, polyester, polyhydroxyalkanoate, polylactic acid, polylactic-co-glycolic acid, polyvinylidene fluoride, polyvinyl acetate, polyvinyl chloride, polystyrene, polytetrafluoroethylene, acrylonitrile-butadiene-styrene, nitrile rubber, styrene butadiene, ethylene vinyl acetate, copolymers thereof, and combinations thereof, more preferably polyolefins, such as polypropylene, polyethylene, copolymers thereof, and combinations thereof. As used herein, the term "polymer" includes copolymers, such as block copolymers.

[0115] In a highly preferred embodiment, the further material is selected from cement, asphalt, geopolymer, or combinations thereof.

[0116] According to the present invention, the cement may be a hydraulic or non-hydraulic cement. In a preferred embodiment, the cement is a hydraulic cement such as Portland cement. In a highly preferred embodiment of the present invention, the cement is one of the cements defined in EN197-1 (2011), preferably Portland cement as defined in EN197-1 (2011).

[0117] In an embodiment of the invention, the composition comprises more than 0.1 wt.-% (by total weight of the composition), preferably more than 1 wt.-%, more preferably more than 5 wt.-% of mechanochemically carbonated natural pozzolan and / or more than 0.1 wt.-% (by total weight of the composition), preferably more than 1 wt.-%, more preferably more than 20 wt.-% of further materials.

[0118] In an embodiment of the invention, the composition comprises less than 60% (by total weight of the composition), preferably less than 50%, more preferably less than 45% by weight of mechanochemically carbonated natural pozzolan and / or less than 95% by weight (by total weight of the composition), preferably less than 90% by weight, more preferably less than 80% by weight of further materials.

[0119] In an embodiment of the present invention, there is provided a composition wherein the weight:weight ratio of mechanochemically carbonated natural pozzolan to further material is in the range of 1:9 to 2:1, preferably in the range of 1:8 to 1:1, more preferably in the range of 1:6 to 5:6.

[0120] In an embodiment of the invention, the composition comprises 5 to 70% by weight (by total weight of the composition), preferably 10 to 60% by weight, more preferably 20 to 50% by weight of mechanochemically carbonated natural pozzolan and 30 to 95% by weight (by total weight of the composition), preferably 40 to 90% by weight, preferably 50 to 80% by weight of further materials.

[0121] In an embodiment of the invention, the composition comprises less than 5 wt. % water (by total weight of the composition), preferably less than 1 wt. %, more preferably less than 0.1 wt. % water, suitably measured as mass loss up to 120° C. as measured by TGAMS using a temperature trajectory ramp from room temperature to 800° C. at a rate of 10° C. / min.

[0122] In an embodiment of the invention, the composition consists of a mechanochemically carbonated natural pozzolan and a further ingredient.

[0123] In another aspect, the present invention provides a method for preparing a composition described herein, said method comprising: (i) providing a mechanochemically carbonated natural pozzolan as described herein, preferably a mechanochemically carbonated natural pozzolan as described herein; (ii) providing a further material selected from the group consisting of asphalt, cement, geopolymer, polymer, and combinations thereof; (iii) combining the mechanochemically carbonated natural pozzolan solids of step (i) with the material of step (ii); The present invention provides a method comprising:

[0124] Method for preparing concrete or mortar Thus, in another aspect, the present invention provides a method for preparing concrete or mortar, comprising the steps of: (i) providing a mechanochemically carbonated natural pozzolan as described herein and, optionally, a further material selected from the group consisting of asphalt, cement, geopolymer, and combinations thereof, in the form of a composition as described herein, wherein the further material is selected from the group consisting of asphalt, cement, geopolymer, and combinations thereof; (ii) providing a structural aggregate; (iii) contacting, preferably mixing, the mechanochemically carbonated natural pozzolan and further material of step (i) with the structural aggregate of step (ii) and, optionally, with water; The present invention provides a method comprising:

[0125] In a preferred embodiment of the present invention, step (iii) further comprises contacting, preferably mixing, the mechanochemically carbonated natural pozzolan and further material of step (i) with the structural aggregate of step (ii) and water. According to the present invention, the mechanochemically carbonated natural pozzolan and further material of step (i), the structural aggregate of step (ii), and water can be contacted, preferably mixed, substantially simultaneously or in stages, where the composition of step (i) is first contacted, preferably mixed, with the water, and thereafter contacted, preferably mixed, with the structural aggregate of step (ii).

[0126] In another aspect, the present invention provides a concrete or mortar obtainable by the method for preparing a concrete or mortar described herein.

[0127] In another aspect, the present invention provides a method for producing a pozzolana comprising the steps of: as a filler, preferably in a material selected from the group consisting of asphalt, cement, geopolymers, mortar, polymers, and combinations thereof; As a partial replacement for asphalt, geopolymers, or cement in concrete or mortar, To increase the compressive strength of concrete or mortar, To improve the durability of concrete or mortar, To reduce the expansion of concrete, To improve the durability of concrete or mortar by reducing chloride permeability and / or porosity, To improve the strength activity index of concrete or mortar, and / or To reduce the water demand of concrete or mortar, Preferably, Incidentally, to improve the strength activity index of concrete and reduce the water demand of concrete, or Concomitantly, to improve the strength activity index of the mortar and reduce the water demand of the mortar. Provide use. [Example]

[0128] Example Measurements of particle size distribution and specific surface area were performed on a Brookhaven Laser Particle Sizer, Model Microbrook 2000LD, using the Fraunhofer theory of light scattering and reporting data using the volume-equivalent sphere model.

[0129] Compressive strength, strength activity index, and water demand were measured according to ASTM C311 / C311M-22.

[0130] CO2 content was measured as mass loss above 450 °C by TGA using a Setaram TAG 16 TGA / DSC dual chamber balance loaded with 0.1–2 mg of sample under an inert nitrogen atmosphere, with a temperature trajectory ramped from room temperature to 800 °C at a rate of 10 °C / min.

[0131] The total carbon content was measured according to the method described in Soil Sampling and Methods of Analysis, 2nd Ed., CRC Press (2008) (pp. 244 ff.).

[0132] The pozzolan precursor obtained from a commercial source was used in the mechanochemical process after passing through a conventional grinding mill.

[0133] Example 1 Sample A Mechanochemically carbonated natural pozzolan was produced by inserting 5 kg of natural pozzolan precursor (zeolite), pretreated by conventional milling, into a pressure cell containing 150 kg of milling media (10 mm ceramic ball bearings). The cell was pressurized with flue gas (8-10% CO2 by volume; 18-20% H2O by volume; 2-3% O2 ​​by volume; 67-72% N2 by volume) to an internal pressure of 448 kPa and rotated with a rotor at 38 RPM for 4 days to obtain mechanochemically carbonated natural pozzolan. The reaction was initiated at room temperature, with no heating or cooling applied. The ceramic bearings contained 92% Al2O3 by weight to also function as a catalyst. The properties of the milled natural pozzolan precursor (A1) and the resulting mechanochemically carbonated natural pozzolan (A2) are shown in the table below.

[0134] Sample B Mechanochemically carbonated natural pozzolan was produced by inserting 10 kg of natural pozzolan precursor (perlite) into a pressure cell containing 150 kg of milling media (10 mm ceramic ball bearings). The cell was pressurized with flue gas (8-10% CO2 by volume; 18-20% H2O by volume; 2-3% O2 ​​by volume; 67-72% N2 by volume) to an internal pressure of 448 kPa and rotated with a rotor at 38 RPM for 2 days to obtain mechanochemically carbonated natural pozzolan. The material was used as received. The reaction was initiated at room temperature, and no heating or cooling was applied. The ceramic bearings had an Al2O3 content of 92 wt% to also function as a catalyst. A portion of the natural pozzolan precursor was passed through conventional milling to serve as a comparative example. The properties of the milled natural pozzolan comparison (B1) and the resulting mechanochemically carbonated natural pozzolan (B2) are shown in the table below.

[0135] Sample C Mechanochemically carbonated natural pozzolan was produced by inserting 10 kg of natural pozzolan precursor (volcanic ash) into a pressure cell containing 100 kg of milling media (ceramic ball bearings, 25.4 mm in size). The cell was pressurized with flue gas (8-10% CO2 by volume; 18-20% H2O by volume; 2-3% O2 ​​by volume; 67-72% N2 by volume) to an internal pressure of 448 kPa and rotated with a rotor at 38 RPM for 2 days to obtain mechanochemically carbonated natural pozzolan. The material was used as received. The reaction was initiated at room temperature, and no heating or cooling was applied. The ceramic bearings had an Al2O3 content of 92% by weight to also function as a catalyst. A portion of the natural pozzolan precursor was passed through conventional milling to serve as a comparative example. The properties of the milled natural pozzolan comparison (C1) and the resulting mechanochemically carbonated natural pozzolan (C2) are shown in the table below.

[0136] Sample D Mechanochemically carbonated natural pozzolan was produced by inserting 8.0 kg of natural pozzolan precursor (basalt) into a pressure cell containing 100 kg of milling media (ceramic ball bearings, 25.4 mm in size). The cell was pressurized with flue gas (8-10% CO2 by volume; 18-20% H2O by volume; 2-3% O2 ​​by volume; 67-72% N2 by volume) to an internal pressure of 448 kPa and rotated with a rotor at 38 RPM for 2 days to obtain mechanochemically carbonated natural pozzolan. The material was used as received. The reaction was initiated at room temperature, and no heating or cooling was applied. The ceramic bearings had an Al2O3 content of 92% by weight to also function as a catalyst. A portion of the natural pozzolan precursor was passed through conventional milling to serve as a comparative example. The properties of the milled natural pozzolan comparison (D1) and the resulting mechanochemically carbonated natural pozzolan (D2) are shown in the table below.

[0137] Sample E Mechanochemically carbonated natural pozzolan was produced by inserting 5.0 kg of natural pozzolan precursor (basalt) into a pressure cell containing 100 kg of milling media (ceramic ball bearings, 25.4 mm in size). The cell was pressurized with flue gas (8-10% CO2 by volume; 18-20% H2O by volume; 2-3% O2 ​​by volume; 67-72% N2 by volume) to an internal pressure of 448 kPa and rotated with a rotor at 38 RPM for 2 days to obtain mechanochemically carbonated natural pozzolan. The material was used as received. The reaction was initiated at room temperature, and no heating or cooling was applied. The ceramic bearings had an Al2O3 content of 92% by weight to also function as a catalyst. A portion of the natural pozzolan precursor was passed through conventional milling to serve as a comparative example. The properties of the milled natural pozzolan comparison (E1) and the resulting mechanochemically carbonated natural pozzolan (E2) are shown in the table below.

[0138] Sample F Mechanochemically carbonated natural pozzolan was produced by inserting 10.0 kg of natural pozzolan precursor (basalt) into a pressure cell containing 100 kg of milling media (ceramic ball bearings, 25.4 mm in size). The cell was pressurized with flue gas (8-10% CO2 by volume; 18-20% H2O by volume; 2-3% O2 ​​by volume; 67-72% N2 by volume) to an internal pressure of 448 kPa and rotated with a rotor at 38 RPM for 2 days to obtain mechanochemically carbonated natural pozzolan. The material was used as received. The reaction was initiated at room temperature, and no heating or cooling was applied. A portion of the natural pozzolan precursor was passed through conventional milling to serve as a comparative example. The ceramic bearings had an Al2O3 content of 92% by weight to also function as a catalyst. The properties of the milled natural pozzolan comparison (F1) and the resulting mechanochemically carbonated natural pozzolan (F2) are shown in the table below.

[0139] Sample G Mechanochemically carbonated natural pozzolan was produced by inserting 8.6 kg of natural pozzolan precursor (basalt) into a pressure cell containing 100 kg of milling media (ceramic ball bearings, 25.4 mm in size). The cell was pressurized with flue gas (8-10% CO2 by volume; 18-20% H2O by volume; 2-3% O2 ​​by volume; 67-72% N2 by volume) to an internal pressure of 448 kPa and rotated with a rotor at 38 RPM for 2 days to obtain mechanochemically carbonated natural pozzolan. The material was used as received. The reaction was initiated at room temperature, and no heating or cooling was applied. The ceramic bearings had an Al2O3 content of 92% by weight to also function as a catalyst. A portion of the natural pozzolan precursor was passed through conventional milling to serve as a comparative example. The properties of the milled natural pozzolan comparison (G1) and the resulting mechanochemically carbonated natural pozzolan (G2) are shown in the table below.

[0140] Sample H Mechanochemically carbonated natural pozzolan was produced by inserting 10.0 kg of natural pozzolan precursor (tuff) into a pressure cell containing 100 kg of milling media (ceramic ball bearings, 25.4 mm in size). The cell was pressurized with flue gas (8-10% CO2 by volume; 18-20% H2O by volume; 2-3% O2 ​​by volume; 67-72% N2 by volume) to an internal pressure of 448 kPa and rotated with a rotor at 38 RPM for 2 days to obtain mechanochemically carbonated natural pozzolan. The material was used as received. The reaction was initiated at room temperature, and no heating or cooling was applied. The ceramic bearings had an Al2O3 content of 92% by weight to also function as a catalyst. A portion of the natural pozzolan precursor was passed through conventional milling to serve as a comparative example. The properties of the milled natural pozzolan comparison (H1) and the resulting mechanochemically carbonated natural pozzolan (H2) are shown in the table below.

[0141] [Table 1]

[0142] As can be observed from the Strength Activity Index (SAI) and water demand measurements, the mechanochemically carbonated natural pozzolan of the present invention unexpectedly results in reduced water demand and increased strength compared to the milled control sample and also compared to the Portland cement control.

Claims

1. 1. A mechanochemically carbonated natural pozzolanic material obtainable by carbonation of a natural pozzolanic precursor, said mechanochemically carbonated natural pozzolanic material having a carbonation rate of 0.5 to 50 m / s. ２ / g, the ratio of the total carbon content of the mechanochemically carbonated natural pozzolan to the total carbon content of the natural pozzolan precursor is at least 1.5:1, preferably at least 2:1, more preferably at least 2.5:1; and / or the CO of the mechanochemically carbonated natural pozzolan ２ content of the natural pozzolan precursor ２ The ratio of CO to CO content is at least 1.1:1, preferably at least 1.3:1, more preferably at least 1.4:1, ２ The content was measured by TGA using a temperature track as mass loss above 450°C, the temperature of which was increased from room temperature to 800°C at a rate of 10°C / min. Mechanochemically carbonated natural pozzolanic material.

2. 2. The mechanochemically carbonated natural pozzolan according to claim 1, having one, two or three, preferably all three, of the following characteristics: D10 in the range of 0.005 to 10 μm, preferably 0.01 to 5 μm, most preferably 0.1 to 3 μm; D50 in the range of 0.1 to 50 μm, preferably 0.5 to 35 μm, most preferably 1 to 15 μm; A D90 in the range of 0.5 to 300 μm, preferably 1 to 300 μm, most preferably 15 to 300 μm.

3. More than 0.5 wt. %, preferably more than 0.6 wt. %, more preferably more than 0.7 wt. % CO (by total weight of said mechanochemically carbonated natural pozzolan) ２ The CO ２ 3. The mechanochemically carbonated natural pozzolan of claim 1 or 2, wherein the content is measured by TGA-MS using a temperature track as mass loss above 450°C, the temperature being increased from room temperature to 800°C at a rate of 10°C / min and then decreased to room temperature at a rate of 10°C / min.

4. 4. The mechanochemically carbonated natural pozzolan according to any one of claims 1 to 3, having a total carbon content of at least 0.25% by weight, preferably at least 0.3% by weight, more preferably at least 0.35% by weight, wherein the natural pozzolan is a zeolite.

5. 5. The mechanochemically carbonated natural pozzolan according to any one of claims 1 to 4, having a Strength Activity Index (SAI), measured according to ASTM C311 / C311M-22 at 7 days, of at least 90%, preferably at least 98%, more preferably at least 120%, and having an SAI at 28 days of at least 100%, preferably at least 105%, more preferably at least 120%.

6. 1. A method for producing a mechanochemically carbonated natural pozzolan, said method comprising: a) providing a raw material comprising or consisting of a natural pozzolan precursor; b) at least 0.5% by volume of CO ２ providing a gas comprising: c) introducing the raw material and the gas into a mechanical stirring unit; d) passing said raw material through a mechanical agitation operation in said mechanical agitation unit in the presence of said gas; A method comprising:

7. The natural pozzolan precursor is 20 m ２ / g, preferably less than 10m ２ / g, more preferably less than 2m ２ 7. The method of claim 6, wherein the particulate material has a specific surface area of ​​less than 1 / g.

8. 8. The method according to claim 6 or 7, wherein the gas provided in step (b) is combustion flue gas, preferably from fossil fuel combustion, wood pellet combustion, biomass combustion, or municipal waste combustion.

9. The step (d) at a pressure of less than 10,000 kPa, preferably less than 5,000 kPa, more preferably less than 2,500 kPa, and most preferably less than 1,000 kPa, and At temperatures below 150°C, preferably below 100°C The method according to any one of claims 6 to 8, wherein the method is carried out

10. 10. The method according to any one of claims 6 to 9, wherein the raw material provided in step (a) is a solid raw material having a moisture content of less than 30 wt.% (total weight of solid raw material), preferably less than 20 wt.%, more preferably less than 15 wt.%.

11. the ratio of the total carbon content of the mechanochemically carbonated natural pozzolan obtained in step (d) to the total carbon content of the natural pozzolan precursor of step (a) is at least 1.5:1, preferably at least 2:1, more preferably at least 2.5:1; and preferably CO2 of the mechanochemically carbonated natural pozzolan obtained in step (d). ２ the CO content of the natural pozzolan precursor of step (a) ２ content ratio of at least 1.2:1, preferably at least 1.3:1, more preferably at least 1.4:1, carbonation, size reduction, and / or surface area increase occurs during step (d); The CO ２ The content was measured by TGA using a temperature track as the mass loss above 450°C, the temperature being increased from room temperature to 800°C at a rate of 10°C / min. The method according to any one of claims 6 to 10.

12. 12. The method according to any one of claims 6 to 11, wherein carbonation, size reduction and / or surface area increase is carried out during step (d) so that the method has one, two or all three, preferably all three, of the following characteristics: CO2 of the mechanochemically carbonated natural pozzolan obtained in step (d) ２ the CO content of the natural pozzolan precursor of step (a) ２ The ratio of CO to CO content is at least 1.5:1, preferably at least 2:1, more preferably at least 3:1, ２ The content was measured by TGA using a temperature track as the mass loss above 450°C, the temperature being increased from room temperature to 800°C at a rate of 10°C / min; the ratio of D50 of the mechanochemically carbonated natural pozzolan obtained in step (d) to D50 of the natural pozzolan precursor of step (a) is less than 0.8:1, preferably less than 0.75:1, more preferably less than 0.5:1; the ratio of the specific surface area of ​​the mechanochemically carbonated natural pozzolan obtained in step (d) to the specific surface area of ​​the natural pozzolan precursor of step (a) is at least 2:1, preferably at least 3:1, more preferably at least 10:

1.

13. A mechanochemically carbonated natural pozzolan obtainable by the method according to any one of claims 6 to 12.

14. 14. A composition comprising the mechanochemically carbonated natural pozzolan of any one of claims 1 to 5 or 13 and a further material selected from the group consisting of asphalt, geopolymer, cement, polymer, and combinations thereof, preferably cement, more preferably Portland cement.

15. 1. A method for preparing concrete or mortar, said method comprising: (i) providing a mechanochemically carbonated natural pozzolan according to any one of claims 1 to 5 or 13, and optionally a further material selected from the group consisting of asphalt, cement, geopolymer, and combinations thereof, in the form of a composition according to claim 14, wherein the further material is selected from the group consisting of asphalt, cement, geopolymer, and combinations thereof; (ii) providing a structural aggregate; (iii) contacting, preferably mixing, the mechanochemically carbonated natural pozzolan and the further material of step (i) with the structural aggregate of step (ii) and, optionally, with water; A method comprising:

16. of the mechanochemically carbonated natural pozzolan according to any one of claims 1 to 5 or 13, as a filler, preferably in a material selected from the group consisting of asphalt, cement, geopolymers, mortar, polymers, and combinations thereof; As a partial replacement for asphalt, geopolymers, or cement in concrete or mortar, - To increase the compressive strength of concrete or mortar, - To improve the durability of concrete or mortar, To improve the durability of concrete or mortar by reducing chloride permeability and / or porosity; - for improving the strength activity index of concrete or mortar, and / or - To reduce the water demand of concrete or mortar, Preferably, - incidentally to improve the strength activity index of concrete and reduce the water demand of concrete, or - concomitantly to improve the strength activity index of the mortar and reduce the water demand of the mortar; use.

Images