Mechanochemically carbonated clay, its production method and use

Abstract

The present invention relates to mechanochemically carbonated clay. The present invention further relates to a method for producing the same and to uses thereof. The present invention further relates to a composition containing the mechanochemically carbonated clay and an additional material selected from the group consisting of asphalt, cement, polymers, and combinations thereof. The present invention further relates to concrete and a method for producing the same.

Description

[Technical Field]

[0001] Technical Field The present invention relates to mechanochemically carbonated clay. The present invention further relates to a method for producing the same and to uses thereof. The present invention further relates to a composition containing the mechanochemically carbonated clay and an additional material selected from the group consisting of asphalt, cement, geopolymers, polymers, and combinations thereof. The present invention further relates to concrete and a method for producing the same. [Background technology]

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

[0003] To reduce the cost of concrete and the CO2 emissions generated by global cement production, numerous research efforts have been made to identify 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 of interest to a wide range of industries.

[0004] An example of a widely used cement filler is limestone. A comprehensive overview of fillers in cementitious materials can be found in 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 insufficient to ensure the necessary mitigation in a scenario where cement demand increases. Currently, cement production is increasing due to a combination of increasing urbanization and the replacement of aging infrastructure. Therefore, cement industry leaders have considered the adoption of carbon capture and storage (CCS) as an inevitable solution, despite its high cost and environmental risks.

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

[0007] US Patent Application Publication No. 2012 / 0055376A1 describes reducing the CO2 footprint of concrete by partially replacing cement with a supplemental cementitious material containing calcined clay and ground carbonate-based material. Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of the present invention to provide an improved filler for cement, geopolymer, or asphalt binders.

[0009] It is a further object of the present invention to provide an improved filler for cement, geopolymer, or asphalt binder that is inexpensive to produce.

[0010] It is a further object of the present invention to provide an improved filler for cement, geopolymer, or asphalt binder produced using CO2 capture technology.

[0011] It is a further object of the present invention to provide an improved filler for cement, geopolymer, or asphalt binder that improves properties such as compressive strength, strength activity index, and / or water demand of the resulting concrete. [Means for solving the problem]

[0012] Summary of the Invention In a first aspect, the present invention provides a method for manufacturing a semiconductor device, preferably a semiconductor device, comprising: 2 / g, preferably obtained by carbonation of a clay precursor, mechanochemically carbonated clay, a ratio of the CO2 content of the mechanochemically carbonated clay to the CO2 content of the clay precursor of at least 1.1:1, preferably at least 1.15:1, more preferably at least 1.2:1, the CO2 content being determined as the mass loss above 450°C measured by TGA using a temperature trace from room temperature to 800°C at a rate of 10°C / min; and / or · the ratio of the total carbon content of the mechanochemically carbonated clay to the total carbon content of the clay precursor is at least 1.3:1, more preferably at least 1.35:1; To provide a mechanochemically carbonated clay.

[0013] VIZCAYNO C ET AL: "Pozzolan obtained by mechanochemical and thermal treatments of kaolin," APPLIED CLAY SCIENCE, ELSEVIER, AMSTERDAM, NL, vol. 49 no. 4, 1 August 2010, pages 405-413, describes the milling of kaolin in an air atmosphere to enhance its pozzolanic activity. As shown in the accompanying examples, e.g., Comparative Example C1 (for calcined clay milled in air) and Comparative Example D1 (for uncalcined clay milled in air), the carbonated clays of the present invention exhibited surprisingly significant improvements in strength activity index at 7 and 28 days compared to calcined and / or air-milled clays.

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

[0015] Since the raw material is preferably solid, the present invention provides a method for producing mechanochemically carbonated clay, comprising: a) providing a solid feedstock comprising or consisting of a clay precursor; b) supplying a gas comprising CO2, preferably a gas comprising at least 0.5% by volume of CO2; c) introducing the solid feedstock and the gas into a mechanical stirring unit; and d) subjecting the solid raw material to mechanical stirring in the presence of the gas in the mechanical stirring unit to obtain mechanochemically carbonated clay; The present invention provides a method comprising:

[0016] This method can be applied to various types of clay precursors and advantageously yields unique mechanochemically carbonated clays.

[0017] In another aspect, the present invention provides mechanochemically carbonated clays obtainable by the methods for making mechanochemically carbonated clays described herein.

[0018] As shown in the accompanying examples, it has been found that the use of such mechanochemically carbonated clays as described herein as fillers in cement surprisingly increases the compressive strength of the resulting concrete beyond that obtainable with non-carbonated clays, and particularly far beyond that of pure Portland cement. In particular, the setting time for strength development is significantly improved (reduced) compared to when non-mechanochemically carbonated clays are used as fillers. Furthermore, much larger amounts of this mechanochemically carbonated clay can be used as a filler while the properties of the concrete remain acceptable or even improved.

[0019] Furthermore, it has been found that the durability of concrete produced using the mechanochemically carbonated clay is significantly improved. Without wishing to be bound by any theory, the inventors believe this is due to improved hydration at the microscale and submicroscale, 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 is believed to improve dispersibility in polar solvents and compatibility with materials containing epoxy or carboxyl functionality.

[0020] Additionally, as shown in the accompanying examples, the water demand is reduced compared to pure cement and compared to cement filled with uncarbonated clay. This is particularly surprising considering the smaller particle size of mechanochemically carbonated clay compared to uncarbonated clay. A reduction in particle size is generally associated with an increase in water demand. A reduction in water demand compared to untreated raw materials or pure cement can contribute to improved properties such as workability, compressive strength, permeability, waterproofing, durability, weathering resistance, drying shrinkage, and cracking potential. For these reasons, limiting and controlling the amount of water in concrete is important for both workability and service life. Thus, the present invention 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 increases the amorphous content as analyzed by XRD, and maintains, via the internal structure, at least some crystalline domains that may be present in the raw materials in a microcrystalline form that maintains a more typical disordered structure. This disordered macrostructure therefore enhances reactivity and improves the hydration of the cement.

[0021] Additionally, because the production of mechanochemically carbonated clays relies on inexpensive CO2 capture technology platforms that can operate with dilute CO2 streams, such as those directly dependent on point source emissions from combustion plants, it can be produced in an economically viable manner, providing a filler that combines both the CO2 emission reductions achieved through reduced cement production and the CO2 emission reductions achieved through CO2 sequestration. Thus, the mechanochemically carbonated clays of the present invention, and in particular the mechanochemically carbonated clays of the present invention, combine unique 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 containing a mechanochemically carbonated clay as described herein and an additional material selected from the group consisting of asphalt, geopolymer, cement, polymer, and combinations thereof.

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

[0024] In another aspect, the present invention provides a method for producing concrete or mortar, comprising the steps of: (i) providing a mechanochemically carbonated clay as described herein and an additional material selected from the group consisting of asphalt, cement, geopolymer, and combinations thereof, optionally in the form of a composition as described herein, wherein the additional material is selected from the group consisting of asphalt, cement, geopolymer, and combinations thereof; (ii) providing construction aggregates; and (iii) contacting, preferably mixing, the mechanochemically carbonated clay and additional material of step (i) with the construction 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 or mortar obtainable by the method for making concrete described herein.

[0026] In another aspect, the present invention provides a method for producing a mechanochemically carbonated clay as described herein, 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, geopolymer, 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, To simultaneously improve the strength activity index of concrete and reduce the water demand of concrete; or ·To simultaneously improve the strength activity index of mortar and reduce the water demand of mortar; Provide use. DETAILED DESCRIPTION OF THE INVENTION

[0027] Description of the embodiment As used herein, the word "comprise" and its variations, such as "comprises" and "comprising," are to be interpreted in an open and inclusive sense, meaning that the described embodiment includes the recited features but does not exclude the presence of other features unless it renders the embodiment impracticable.

[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 characteristic 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 separate embodiments are expressly contemplated as being combined in a single embodiment.

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

[0030] Throughout this specification, references to compounds that are salts should always be taken to include the anhydrous form of the compound as well as solvates (especially hydrates).

[0031] The terms "clay precursor" and "clay" as used herein should be interpreted as a solid material containing at least 50% by weight of hydrous aluminum phyllosilicate, preferably at least 75% by weight of hydrous aluminum phyllosilicate, more preferably at least 90% by weight of hydrous aluminum phyllosilicate. The hydrous aluminum phyllosilicate is preferably selected from the kaolin group, the smectite group, the vermiculite group, or mixtures thereof. The clay may be calcined or uncalcined.

[0032] The term "mechanochemically carbonated clay" is used herein to refer to clay obtained by the mechanochemical carbonation process of the present invention.

[0033] According to the present invention, the BET surface area referred to herein is determined at a temperature of 77 K using a sample mass of 0.1 to 0.5 g. The BET surface area referred to herein is determined using nitrogen. A preferred analytical method for determining the 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 determining the BET surface area is a Micromeritics Gemini VII 2390 surface analyzer, preferably equipped with a Micromeritics FlowPrep 060 flow gas degassing unit.

[0034] As used herein, TGA refers to thermogravimetric analysis, a technique known to those skilled in the art. A preferred TGA configuration for determining the CO2 content of raw and carbonated materials in the context of this invention 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 in an inert atmosphere such as nitrogen or argon.

[0035] According to the present invention, particle size distribution characteristics such as D10, D50, and D90, as well as specific surface area (unless explicitly stated to be BET surface area) referred to herein are determined by measuring with a laser light scattering particle size analyzer utilizing Fraunhofer light scattering theory, such as a Brookhaven laser particle size analyzer, model Microbrook 2000LD, or other instrument with equivalent or greater sensitivity, and reporting the data using a volume-equivalent sphere model. As known to those skilled in the art, D50 is the median diameter by mass, 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.

[0036] The total carbon (TC) content referred to herein is preferably determined according to the method described in Soil Sampling and Methods of Analysis, 2nd Ed., CRC Press (2008), p. 244 et seq., which is incorporated by reference. The total carbon (TC) content is always expressed herein as a weight percent based on the total weight of the composition being measured, i.e., the total weight of the clay precursors or the total weight of the carbonated clay.

[0037] In accordance with the present invention, the compressive strength, strength activity index, and water demand referred to herein are determined in accordance with ASTM C311 / C311 M-22. As will be apparent to those skilled in the art, in conducting these tests, a clay precursor or carbonated clay of the present invention was used in place of the "fly ash or natural pozzolan" specified in the standard.

[0038] For purposes of this disclosure, the ideal gas law is assumed so that volume percent of a gas is considered to be equivalent to mole percent.

[0039] Mechanochemically carbonated clay In a first aspect, the present invention provides a method for manufacturing a semiconductor device, preferably a semiconductor device, comprising: 2 The mechanochemically carbonated clay has a specific surface area of less than 1 / g. The mechanochemically carbonated clay preferably has a CO2 content of greater than 0.8 wt% (based on the total weight of the mechanochemically carbonated clay), preferably greater than 1 wt% (based on the total weight of the mechanochemically carbonated clay), and more preferably greater than 1.5 wt% (based on the total weight of the mechanochemically carbonated clay), where the CO2 content is determined as the mass loss at a temperature above 450°C, measured by TGA using a temperature trace in which the temperature is increased from room temperature to 800°C at a rate of 10°C / min. The mechanochemically carbonated clay is obtained by carbonation of a clay precursor.

[0040] In a preferred embodiment, the mechanochemically carbonated clay meets the strength requirements set forth in ASTM C618-12a(2012).

[0041] In a preferred embodiment of the present invention, the mechanochemically carbonated clay has a surface area of at least 0.6 m 2 / g, preferably at least 0.7m 2 / g, more preferably at least 0.8m 2 / g specific surface area.

[0042] In a preferred embodiment of the present invention, the mechanochemically carbonated clay has a particle size of 50 μm 2 / g, preferably less than 30 μm 2 / g, more preferably less than 15 μm 2 / g. For example, mechanochemically carbonated clays have specific surface areas up to 50 m 2 / g, up to 48m 2 / g, up to 46m 2 / g, up to 44m 2 / g, up to 42m 2 / g, up to 40m 2 / g, up to 38m 2 / g, up to 36m 2 / g, up to 34m 2 / g, up to 32m 2 / g, up to 30m 2 / g, up to 28m 2 / g, up to 26m 2 / g, up to 24m 2 / g, up to 22m 2 / g, up to 20m 2 / g, up to 18m 2 / g, up to 16m 2 / g, up to 15m 2 / g, up to 12m 2 / g, up to 10m 2 / g, up to 8m 2 / g, up to 6m 2 / g, up to 4m 2 / g, up to 2m 2 / g.

[0043] In a highly preferred embodiment of the present invention, the mechanochemically carbonated clay has a particle size of 5 μm 2 / g, preferably less than 3 μm 2 / g, more preferably less than 2 μm 2 / g. For example, mechanochemically carbonated clays 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 clays having specific surface areas within the ranges specified herein have particular properties, such as performance and handling characteristics, compared to their untreated precursors, and also compared to carbonated materials having other surface areas. Thus, in accordance with a highly preferred embodiment of the present invention, mechanochemically carbonated clays have specific surface areas within the range specified in accordance with the combination of the upper and lower limits set forth herein, e.g., 0.3 to 50 m. 2 / g, preferably 0.3 to 30m 2 / g, more preferably 0.3 to 10m 2 Specific surface area in the range of 0.4~50m / g 2 / g, preferably 0.4 to 30m 2 / g, more preferably 0.4 to 10m 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 0.3~5.0m / g 2 / g, preferably 0.3 to 3.0 m 2 / g, more preferably 0.3 to 2.0m 2 Specific surface area in the range of 0.4~5.0m / g 2 / g, preferably 0.4 to 3.0 m 2 / g, more preferably 0.4 to 2.0 m 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 embodiments of the present invention, the mechanochemically carbonated clay has one, two, or three, preferably three, of the following characteristics: D10 in the range of 0.005 to 3 μm, preferably 0.01 to 2 μm, most preferably 0.1 to 1.4 μm; D50 in the range of 0.1 to 30 μm, preferably 0.5 to 15 μm, most preferably 1 to 10 μm; D90 in the range of 0.5 to 100 μm, preferably 1 to 80 μm, most preferably 5 to 70 μm.

[0046] In embodiments of the present invention, there is provided a mechanochemically carbonated clay as described herein obtained by simultaneous carbonation and size reduction of a clay precursor, wherein the ratio of D50 of the mechanochemically carbonated clay to D50 of the clay precursor is less than 0.5:1, preferably less than 0.1:1, more preferably less than 0.05:1.

[0047] In some embodiments of the present invention, the mechanochemically carbonated clay has a total carbon content of at least 0.75% by weight, preferably at least 0.85% by weight, and more preferably at least 0.9% by weight. The inventors have observed that mechanochemically carbonated clays having a total carbon content of at least 1% by weight, preferably at least 1.5% by weight, and more preferably at least 2% by weight, provide even better results. Thus, in a preferred embodiment, the mechanochemically carbonated clay has a total carbon content of at least 1% by weight, preferably at least 1.5% by weight, and more preferably at least 2% by weight, providing even better results. Preferably, the mechanochemically carbonated clay is obtained by carbonation of a clay precursor in which the ratio of the total carbon content of the mechanochemically carbonated clay to the total carbon content of the clay precursor is at least 1.3:1, more preferably at least 1.35:1. The inventors have observed that methods in which the ratio is at least 1.4:1, preferably at least 1.6:1, and more preferably at least 1.8:1, provide even better results, and are therefore preferred. Similarly, the mechanochemically carbonated clay is preferably obtained by carbonation of a clay precursor in which the ratio of the CO2 content of the mechanochemically carbonated clay to the CO2 content of the clay precursor is at least 1.1:1, preferably at least 1.15:1, more preferably at least 1.2:1, where the CO2 content is determined as the mass loss above 450°C, measured by TGA using a temperature trace in which the temperature is increased from room temperature to 800°C at a rate of 10°C / min. More preferably, the ratio of the CO2 content of the mechanochemically carbonated clay to the CO2 content of the clay precursor is at least 1.5:1, preferably at least 1.75:1, more preferably at least 2:1, where the CO2 content is determined as the mass loss above 450°C, measured by TGA using a temperature trace in which the temperature is increased from room temperature to 800°C at a rate of 10°C / min.

[0048] Without wishing to be bound by any theory, the inventors believe that the increase in specific surface area provided 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 clays as described herein obtained by the simultaneous carbonation and increase in specific surface area of a clay precursor, wherein the ratio of the specific surface area of the mechanochemically carbonated clay to the specific surface area of the clay precursor is at least 1.2:1, preferably at least 1.4:1, and more preferably at least 1.6:1.

[0049] Without wishing to be bound by any theory, the inventors believe that the increased BET surface area provided 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 clays as described herein obtained by the simultaneous carbonation and BET surface area increase of a clay precursor, wherein the ratio of the BET surface area of the mechanochemically carbonated clay to the BET surface area of the clay precursor is at least 2:1, preferably at least 3:1, and more preferably at least 3.5:1.

[0050] Without wishing to be bound by any theory, the inventors believe that the increase in BET surface area provided by the dry mechanochemical carbonation process of another aspect of the invention (described elsewhere herein) can be primarily attributed to the increase in the number of pores observed due to the decrease in average pore width and the increase in total pore surface area. Accordingly, embodiments of the invention provide mechanochemically carbonated clays obtained by the simultaneous carbonation and BET surface area increase of a clay precursor, wherein the BJH desorption cumulative surface area of the pores of the mechanochemically carbonated clay 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 clay precursor, and the desorption average pore width (BET 4V / A) of the mechanochemically carbonated clay 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 clay precursor.

[0051] According to the present invention, mechanochemically carbonated clays typically have 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 results in carbonated clays with excellent 7-day SAI. Thus, in a preferred embodiment, the mechanochemically carbonated clays have a 7-day SAI of at least 105%, preferably at least 110%, and more preferably at least 125%.

[0052] In embodiments of the present invention, the mechanochemically carbonated clay has a 28-day Strength Activity Index (SAI) of at least 75%, preferably at least 95%, and more preferably at least 100%. The inventors have observed that the mechanochemical process of the present invention results in carbonated clays with excellent 28-day SAI. Thus, in preferred embodiments, the mechanochemically carbonated clay has a 28-day SAI of at least 110%, preferably at least 115%, and more preferably at least 125%.

[0053] In some embodiments of the present invention, the mechanochemically carbonated clay has a water demand of less than 97%, preferably less than 96%, and more preferably less than 95%. The inventors have observed that the mechanochemical process of the present invention results in carbonated clays with extremely low water demands. Thus, in a preferred embodiment, the mechanochemically carbonated clay has a water demand of less than 93%, preferably less than 91%.

[0054] In a preferred embodiment of the present invention, the clay precursor comprises CaO and / or Ca(OH), preferably the clay precursor comprises at least 0.1 wt. % CaO and / or Ca(OH) (based on the total weight of the clay precursor), preferably at least 0.5 wt. % CaO and / or Ca(OH) (based on the total weight of the clay precursor).

[0055] Method for producing mechanochemically carbonated clay and mechanochemically carbonated clay obtained 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 clay obtained thereby. For example, the unique surface area and pore characteristics provided by the dry mechanochemical carbonation process of the present invention are believed to be important for realizing the surprising performance of the material in, for example, concrete.

[0056] In a further aspect, the present invention provides a method for producing a mechanochemically carbonated clay, comprising the steps of: a) providing a feedstock comprising or consisting of a clay precursor; b) supplying a gas comprising CO2, preferably a gas comprising at least 0.5% by volume of CO2; c) introducing the raw material and the gas into a mechanical stirring unit; and d) subjecting the raw material to mechanical stirring in the presence of the gas in the mechanical stirring unit to obtain mechanochemically carbonated clay; The present invention provides a method comprising:

[0057] The raw material is preferably a solid raw material, and therefore the present invention very preferably relates to a method for producing mechanochemically carbonated clay, comprising the steps of: a) providing a solid feedstock comprising or consisting of a clay precursor; b) supplying a gas comprising CO2, preferably a gas comprising at least 0.5% by volume of CO2; c) introducing the solid feedstock and the gas into a mechanical stirring unit; and d) subjecting the solid raw material to mechanical stirring in the presence of the gas in the mechanical stirring unit to obtain mechanochemically carbonated clay; The present invention provides a method comprising:

[0058] Process Description The term "feedstock" should be interpreted as a material consisting of or including a clay precursor. The clay may be mixed with other materials to form the feedstock (such as when shale is used as the feedstock), or may consist essentially of clay. The term "precursor" is used to refer to the clay prior to undergoing the mechanochemical carbonation of the present invention. Preferably, however, the feedstock consists essentially of the clay precursor and optional water, which allows the process conditions to be optimized to achieve the desired carbonated clay properties without considering the properties of other materials present in the feedstock.

[0059] Given the guidance provided in this disclosure, it is within the ability of one skilled in the art to adjust the relevant process parameters to obtain mechanochemically carbonated clays having the properties enumerated herein.

[0060] The gas provided in step (b) may be any gas stream containing CO2, such as ordinary air, a waste gas stream having a low CO2 concentration, or a concentrated CO2 stream.

[0061] In embodiments of the methods described herein, the gas provided in step (b) is ordinary air.

[0062] In a highly preferred embodiment of the method described herein, the gas provided in step (b) is flue gas, particularly flue gas from fossil fuel combustion, wood pellet combustion, biomass combustion, or municipal waste combustion. The fossil fuel combustion may be coal, petroleum coke, oil, natural gas, shale oil, bitumen, tar sands oil, or heavy oil combustion, or any combination thereof. The flue gas may optionally be treated to reduce its water content, SO2 content, and / or NOx content.

[0063] The CO concentration in 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 flue gases range from 1 to 15% by volume, e.g., 2 to 10% by volume, so the gas provided in step (b) preferably has a CO concentration in the range of 1 to 15% by volume, e.g., 2 to 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 to 25% by volume of HO. For example, in the case of exhaust gas, the gas provided in step (b) preferably comprises CO in the range of 1-15 vol%, e.g., 2-10 vol%, and HO in the range of 5-25 vol%, e.g., 15-20 vol%. The gas is typically not in a supercritical state, as supercritical conditions are 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.

[0064] In some embodiments of the present invention, the methods described herein are provided with the proviso that the temperature and pressure during step (d) are less than the saturated vapor pressure of water at the temperature in the mechanically stirred unit.

[0065] The phrase "in the presence of said gas" in step (d) should be interpreted to mean that when step (d) is initiated, the atmosphere within the mechanically stirred unit consists essentially of the gas provided in step (b). Those skilled in the art will understand that the composition of the gas will change as the reaction progresses unless the reactor (mechanically stirred unit) is continuously purged or refilled.

[0066] Typically, step (d) can be carried out at atmospheric pressure, below atmospheric pressure, or above atmospheric pressure. Typically, step (d) is preferably carried out at atmospheric pressure or above. Thus, 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 greater than 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), for example, less than 50 kPa or less than 10 kPa. Those skilled in the art will appreciate that the pressure of the gas will change (if not actively maintained) as the reaction progresses. In these embodiments, it should be understood that when step (d) is initiated, the pressure within the mechanical stirring unit is as defined herein. In some embodiments, throughout most or substantially all of step (d), the pressure within the mechanical agitation unit is as defined herein.

[0067] 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 produce the mechanochemically carbonated clays 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. Those skilled in the art will appreciate that the gas pressure will change (if not actively maintained) as the reaction progresses. In these embodiments, it should be understood that the pressure within the mechanically agitated unit is as defined herein at at least one point during step (d), e.g., when step (d) is initiated. In some embodiments, the pressure within the mechanically agitated unit is as defined herein throughout most or substantially all of step (d).

[0068] In a highly preferred embodiment of the method described herein, 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 to promote carbonation. 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 performed, and the temperature increase is due to friction from mechanical agitation or the exothermic reaction that occurs during mechanochemical carbonation. The temperature is preferably determined by the solid material in the reactor (i.e., the mechanical agitation unit) during processing.

[0069] In embodiments 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.

[0070] 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 function to increase the solubility of carbon dioxide in aqueous solutions and allow for the formation of carbonate concentrations for sequestering carbon dioxide.

[0071] The low temperature requirements of the process mean that no fossil fuels are required and, where the friction generated by mechanical agitation is insufficient to reach a target temperature such as above 45°C, it is feasible to use electrical heating means (or low calorific value green fuel sources) to provide heat, thus avoiding fossil fuels throughout the production chain.

[0072] As with any chemical process, the appropriate reaction time will depend largely on the degree of carbonation desired, the surface area desired, and the applied pressure, temperature, and mechanochemical agitation, and can be readily determined by periodically sampling the material and following the progress of the reaction via, for example, BET analysis, particle size analysis, and total carbon determination as described herein.

[0073] The inventors have further found that the mechanochemical carbonation processes described herein can be advantageously carried out without the use of an additional oxidizing agent, such as an acid. Accordingly, the mechanochemical carbonation processes described herein are preferably carried out without the use of a strong acid, and preferably without the use of an additional oxidizing agent other than the gas provided in step (b).

[0074] 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, pulverizing, powdering, crushing, disintegration, 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 found that the mechanochemical carbonation process is accelerated 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 of the present invention, 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, the 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 obtained by the process of the present invention, when performed in a rotating drum, may also be obtained using alternative grinding or milling techniques known to those skilled in the art.

[0075] 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.

[0076] Thus, as can be appreciated 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, micronizing, pulverizing, crushing, disintegrating, fluidized bed or sonicating in the presence of grinding or milling media and a metal oxide catalyst, preferably grinding, milling, mixing, stirring (such as slow or high speed stirring), shearing (such as high torque shear) or sonicating.

[0077] The inventors have found that it is advantageous in terms of mechanochemical carbonation efficiency (e.g., reaction time, CO2 absorption, particle size reduction) to employ a medium as described herein above that includes the metal oxide catalyst (e.g., as a coating), and / or to employ a mechanical agitation unit (or part thereof) that includes (or includes as a coating) the metal oxide catalyst on one or more surfaces that come into contact with the feedstock, e.g., during step (d). As described elsewhere herein, the mechanical agitation operation may simply be the rotation of a mechanical agitation unit that includes the feedstock or clay precursor for mechanochemical carbonation, grinding or milling media, metal oxide catalyst, and gas. This can be conveniently performed in a rotating drum.

[0078] As will be apparent from the present specification, in highly preferred embodiments, step (d) is a substantially dry process. It is highly preferred that step (d) is not performed with an aqueous solution or slurry, although the presence of some moisture is acceptable and beneficial to carbonation efficiency. The inventors have found that performing step (d) on a solid material provides significant energy efficiency (since there is no need to subsequently remove water) and imparts unique properties to the resulting mechanochemically carbonated clay, resulting in a material that is substantially different from, for example, aqueous carbonated materials. This is also reflected in their unique properties when used, for example, as a filler in concrete. In several embodiments of the present invention, the solid raw material preferably has a moisture content of less than 30% by weight (based on the total weight of the solid raw material), preferably less than 20% by weight.

[0079] According to a highly preferred embodiment of the present invention, the feedstock provided in step (a) is a solid feedstock. The solid feedstock provided in step (a) highly preferably has a moisture content of less than 30 wt. %, preferably less than 20 wt. %, more preferably less than 15 wt. % (based on the total weight of the solid feedstock). From the standpoint of carbonation efficiency, the solid feedstock preferably has a moisture content of at least 2 wt. %, preferably at least 5 wt. %, more preferably at least 10 wt. % (based on the total weight of the solid feedstock). At a moisture content of less than 30 wt. % (based on the total weight of the solid feedstock), the feedstock remains solid and behaves like a solid. In some embodiments of the present invention, the solid feedstock may have a moisture content of less than 10 wt. %, less than 5 wt. %, or less than 2 wt. % (based on the total weight of the solid feedstock). The solid feedstock preferably has a moisture content as defined herein at at least one point during step (d), for example, when step (d) is initiated. In some embodiments, the moisture content of the feedstock remains as defined herein throughout most or substantially all of step (d).

[0080] Based on the guidance provided herein, it is within the ordinary skill of one of ordinary skill in the art to adjust the moisture content of the feedstock, for example, by spraying an aqueous composition such as water onto the solid feedstock prior to and / or during step (d).

[0081] In another embodiment, the feedstock provided in step (a) is an aqueous slurry, solution, or suspension, such as an aqueous slurry. The feedstock aqueous slurry, solution, or suspension provided in step (a) can have a water content of more than 50 wt. % (based on the total weight of the feedstock aqueous slurry, solution, or suspension), for example, more than 70 wt. %. The feedstock aqueous slurry, solution, or suspension preferably has a water content as defined herein at at least one point during step (d), for example, at the start of step (d). In some embodiments, the water content of the feedstock aqueous slurry, solution, or suspension is as defined herein throughout most or substantially all of step (d).

[0082] In some embodiments, step (d) is followed by a dehydration step to reduce the water content of the resulting mechanochemically carbonated glassy solid.

[0083] In particular, the inventors have found that it is important that step (d) is carried out in a manner that results in some degree of carbonation, size reduction, and / or surface area increase during step (d), i.e., the combination of carbonation and mechanical agitation. This results in a material that is significantly different from, for example, material that has been ground and then carbonated. To achieve these effects, it is preferred that step (a) of the method comprises providing a solid feedstock as described hereinabove, and that step (d) is carried out on the solid feedstock provided in step (a).

[0084] Thus, in a highly preferred embodiment of the present invention, carbonation, size reduction, and / or surface area increase is effected during step (d), resulting in the following characteristics: the ratio of the CO2 content of the mechanochemically carbonated clay obtained in step (d) to the CO2 content of the clay precursor of step (a) is at least 1.1:1, preferably at least 1.15:1, more preferably at least 1.2:1, wherein the CO2 content is determined as the mass loss above 450°C measured by TGA using a temperature trace from room temperature to 800°C at a rate of 10°C / min; the ratio of D50 of the mechanochemically carbonated clay obtained in step (d) to D50 of the clay precursor of step (a) is less than 0.9:1, preferably less than 0.85:1, more preferably less than 0.8:1; the ratio of the specific surface area of the mechanochemically carbonated clay obtained in step (d) to the specific surface area of the clay precursor of step (a) is at least 1.15:1, preferably at least 1.2:1, more preferably at least 1.25:1; The method of the present invention is provided having one, two or all three of the following, preferably all three:

[0085] As shown in the examples, certain materials also have improved strength and / or water demand properties. Thus, in some particularly preferred embodiments of the present invention, carbonation, size reduction, and / or surface area increase are provided during step (d), resulting in the following characteristics: the ratio of the CO2 content of the mechanochemically carbonated clay obtained in step (d) to the CO2 content of the clay precursor of step (a) is at least 1.5:1, preferably at least 1.75:1, more preferably at least 2:1, wherein the CO2 content is determined as the mass loss above 450°C measured by TGA using a temperature trace in which the temperature is increased from room temperature to 800°C at a rate of 10°C / min; the ratio of D50 of the mechanochemically carbonated clay obtained in step (d) to D50 of the clay precursor of step (a) is less than 0.8:1, preferably less than 0.75:1, more preferably less than 0.1:1; the ratio of the specific surface area of the mechanochemically carbonated clay obtained in step (d) to the specific surface area of the clay precursor of step (a) is at least 2:1, preferably at least 5:1, more preferably at least 10:1; The method of the present invention is provided having one, two or all three of the following, preferably all three:

[0086] The inventors have observed that it is preferred for the process of the invention that the carbonation is carried out during step (d) so that the ratio of the total carbon content of the mechanochemically carbonated clay obtained in step (d) to the total carbon content of the clay precursor of step (a) is at least 1.3: 1, more preferably at least 1.35: 1. The inventors have observed that processes in which said ratio is at least 1.4: 1, preferably at least 1.6: 1, more preferably at least 1.8: 1, give even better results and are therefore preferred.

[0087] Without wishing to be bound by any theory, the inventors believe that the increase in BET surface area provided by the dry mechanochemical carbonation process is related to the observed beneficial properties, such as superior strength activity index and reduced water demand. Thus, in a highly preferred embodiment of the present invention, there is provided a process in which carbonation and an increase in BET surface area are provided during step (d) such that the ratio of the BET surface area of the mechanochemically carbonated clay to the BET surface area of the clay precursor is at least 2:1, preferably at least 3:1, more preferably at least 3.5:1.

[0088] Those skilled in the art will appreciate that since the material of step (a) is fed to step (d), this means that carbonation, size reduction, and / or the surface area as defined above is achieved during step (d).

[0089] In a particularly preferred embodiment of the method of the present invention, the BJH desorption cumulative surface area of the pores of the mechanochemically carbonated clay 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 clay precursor, and the desorption average pore width (4V / A by BET) of the mechanochemically carbonated clay obtained in step (d) is at most 90%, preferably at most 85%, more preferably at most 80% of the desorption average pore width (4V / A by BET) of the clay precursor.

[0090] In embodiments of the present invention, the methods described herein do not comprise a solid-liquid separation step selected from filtration, decantation, and gravity separation (e.g., using a cyclone) after step (d), and preferably the methods of the present invention do not comprise any solid-liquid separation step after step (d).

[0091] In embodiments of the present invention, the methods described herein do not include a size selection step, such as a screening or sieving step, after step (d).

[0092] Properties of the clay precursor used in the mechanochemical carbonation method of the present invention In a preferred embodiment of the method described herein, the clay precursor is 20 μm 2 less than / g, preferably 10 μm 2 less than / g, more preferably 2 μm 2 and is a particulate solid material having a specific surface area less than / g.

[0093] In a highly preferred embodiment of the present invention, the clay precursor has one, two, or three, preferably three, of the following characteristics: · D10 within the range of 0.1 to 50 μm, preferably 0.1 to 20 μm, most preferably 0.1 to 10 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 1000 μm, preferably 20 to 750 μm, most preferably 40 to 500 μm.

[0094] In a preferred embodiment of the present invention, the clay precursor contains CaO and / or Ca(OH)2, preferably the clay precursor contains at least 0.1 wt% CaO and / or Ca(OH)2 (based on the total weight of the clay precursor), preferably at least 0.5 wt% CaO and / or Ca(OH)2 (based on the total weight of the clay precursor).

[0095] Properties of the mechanochemically carbonated clay obtained in step (d) In a preferred embodiment of the method for producing the carbonated clay described herein, the carbonated clay obtained in step (d) is 50 m 2The mechanochemically carbonated clay obtained in step (d) preferably has a CO2 content of more than 0.8 wt% (based on the total weight of the mechanochemically carbonated clay), preferably more than 1 wt% (based on the total weight of the mechanochemically carbonated clay), more preferably more than 1.5 wt% (based on the total weight of the mechanochemically carbonated clay), where the CO2 content is determined as the mass loss at temperatures above 450°C measured by TGA using a temperature trace in which the temperature is increased from room temperature to 800°C at a rate of 10°C / min.

[0096] In preferred embodiments, the mechanochemically carbonated clay obtained in step (d) meets the strength requirements set forth in ASTM C618-12a(2012). In certain embodiments, the methods described herein do not include a size separation step, such as a screening or sieving step, after step (d), and the carbonated clay obtained in step (d) meets the strength requirements set forth in ASTM C618-12a(2012).

[0097] In a preferred embodiment of the present invention, the mechanochemically carbonated clay obtained in step (d) has a surface area of at least 0.6 m 2 / g, preferably at least 0.7m 2 / g, more preferably at least 0.8m 2 / g specific surface area.

[0098] In a preferred embodiment of the present invention, the mechanochemically carbonated clay obtained in step (d) has a particle size of 50 μm 2 / g, preferably less than 30 μm 2 / g, more preferably less than 15 μm 2 For example, the mechanochemically carbonated clay obtained in step (d) has a specific surface area of up to 50 m 2 / g, up to 48m 2 / g, up to 46m 2 / g, up to 44m 2 / g, up to 42m 2 / g, up to 40m 2 / g, up to 38m 2 / g, up to 36m 2 / g, up to 34m 2 / g, up to 32m 2 / g, up to 30m 2 / g, up to 28m 2 / g, up to 26m 2 / g, up to 24m 2 / g, up to 22m 2 / g, up to 20m 2 / g, up to 18m 2 / g, up to 16m 2 / g, up to 15m 2 / g, up to 12m 2 / g, up to 10m 2 / g, up to 8m 2 / g, up to 6m 2 / g, up to 4m 2 / g, up to 2m 2 / g.

[0099] In a highly preferred embodiment of the present invention, the mechanochemically carbonated clay obtained in step (d) has a particle size of 5 μm 2 / g, preferably less than 3 μm 2 / g, more preferably less than 2 μm 2 / g. For example, mechanochemically carbonated clays 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.

[0100] The inventors have observed that mechanochemically carbonated clays having a specific surface area within the ranges specified herein have certain properties, such as performance and handling characteristics, compared to the untreated precursor and also compared to carbonated materials having other surface areas. Thus, according to a highly preferred embodiment of the present invention, the mechanochemically carbonated clay obtained in step (d) has a specific surface area within the range specified in accordance with the combination of the upper and lower limits set forth herein, for example, 0.6 to 50 m. 2 / g, preferably 0.6 to 30m 2 / g, more preferably 0.6 to 10m 2 Specific surface area in the range of 0.8~50m / g 2 / g, preferably 0.8 to 30m 2 / g, more preferably 0.8 to 10m 2 Specific surface area in the range of / g; 1~50m 2 / g, preferably 1 to 30m 2 / g, more preferably 1 to 10m 2 Specific surface area in the range of 0.6~5.0m / g 2 / g, preferably 0.6 to 3.0 m 2 / g, more preferably 0.6 to 2.0 m 2 Specific surface area in the range of 0.8~5.0m / g 2 / g, preferably 0.8 to 3.0 m 2 / g, more preferably 0.8 to 2.0 m 2 Specific surface area in the range of / g; 1~5.0m 2 / g, preferably 1 to 3.0 m 2 / g, more preferably 1 to 2.0 m 2 / g range.

[0101] In embodiments of the present invention, the mechanochemically carbonated clay obtained in step (d) has one, two or three, preferably three, of the following characteristics: D10 in the range of 0.005 to 3 μm, preferably 0.01 to 2 μm, most preferably 0.1 to 1.4 μm; D50 in the range of 0.1 to 30 μm, preferably 0.5 to 15 μm, most preferably 1 to 10 μm; D90 in the range of 0.5 to 100 μm, preferably 1 to 80 μm, most preferably 5 to 70 μm.

[0102] In some embodiments of the present invention, the mechanochemically carbonated clay obtained in step (d) has a total carbon content of at least 0.75% by weight, preferably at least 0.85% by weight, more preferably at least 0.9% by weight. The inventors have observed that mechanochemically carbonated clays having a total carbon content of at least 1% by weight, preferably at least 1.5% by weight, more preferably at least 2% by weight, provide even better results. Thus, in a preferred embodiment, the mechanochemically carbonated clay obtained in step (d) has a total carbon content of at least 1% by weight, preferably at least 1.5% by weight, more preferably at least 2% by weight, which provides even better results.

[0103] According to the present invention, the mechanochemically carbonated clay obtained in step (d) typically 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 results in carbonated clays with excellent 7-day SAI. Thus, in a preferred embodiment, the mechanochemically carbonated clay obtained in step (d) has a 7-day SAI of at least 105%, preferably at least 110%, and more preferably at least 125%.

[0104] In embodiments of the present invention, the mechanochemically carbonated clay obtained in step (d) has a 28-day Strength Activity Index (SAI) of at least 75%, preferably at least 95%, and more preferably at least 100%. The inventors have observed that the mechanochemical process of the present invention results in carbonated clays with excellent 28-day SAI. Thus, in a preferred embodiment, the mechanochemically carbonated clay obtained in step (d) has a 28-day SAI of at least 110%, preferably at least 115%, and more preferably at least 125%.

[0105] In some embodiments of the present invention, the mechanochemically carbonated clay obtained in step (d) has a water demand of less than 97%, preferably less than 96%, more preferably less than 95%. The inventors have observed that the mechanochemical process of the present invention produces carbonated clays with extremely low water demands. Thus, in a preferred embodiment, the mechanochemically carbonated clay obtained in step (d) has a water demand of less than 93%, preferably less than 91%.

[0106] Mechanochemically carbonated clay obtained by the method described herein The inventors have found that the mechanochemical carbonation described herein imparts unique properties to the resulting mechanochemically carbonated clays, resulting in materials that are substantially different from, for example, aqueous carbonated materials. This is reflected in their unique properties when used, for example, as a filler in concrete. In particular, the inventors have found that it is important that step (d) is conducted in a manner that results in a degree of carbonation, size reduction, and / or surface area increase during step (d), i.e., the combination of carbonation and mechanical agitation. This results in a material that is significantly different from, for example, materials carbonated in an aqueous environment, or even from materials that have been ground and subsequently carbonated.

[0107] Thus, in another aspect, the present invention provides a mechanochemically carbonated clay obtainable by the method for producing a mechanochemically carbonated clay described herein.

[0108] In light of this disclosure, one of skill in the art will appreciate that the mechanochemically carbonated clays of the present invention combine unique mechanical properties with a cost-effective approach to CO2 sequestration, making them excellent fillers for many applications.

[0109] Compositions containing mechanochemically carbonated clay and methods for producing same Thus, in another aspect, the present invention provides a composition containing a mechanochemically carbonated clay as described herein and an additional material selected from the group consisting of asphalt, cement, geopolymer, polymer, and combinations thereof, preferably cement, more preferably Portland cement.

[0110] In some embodiments of the present invention, the additional material is a polymer selected from thermoplastic polymers and thermosetting polymers. In a preferred embodiment of the present invention, the additional component is selected from the group consisting of epoxide resins, phenol-formaldehyde resins, polyalkylene terephthalates (preferably polyethylene terephthalate), polyalkylene adipate terephthalates (preferably polybutylene adipate terephthalate), polyalkylene isosorbide terephthalates (preferably polyethylene isosorbide terephthalate), polyalkylene aromatic polyamides (preferably polyethylene aromatic polyamides), polyacrylonitrile, polyacetal, polyimides, aromatic polyesters, polyisoprenes (preferably cis-1,4-polyisoprenes), polyethylene The polymer is preferably selected from the group consisting of 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 from the group consisting of polyolefins such as polypropylene and polyethylene, copolymers thereof, and combinations thereof. As used herein, the term "polymer" includes copolymers, such as block copolymers.

[0111] In a highly preferred embodiment, the additional material is selected from cement, asphalt, geopolymer, or combinations thereof.

[0112] According to the present invention, the cement may be a hydraulic cement or a non-hydraulic cement. In a preferred embodiment of the present invention, 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 specified in EN197-1(2011), preferably Portland cement specified in EN197-1(2011).

[0113] In embodiments of the present invention, the composition contains at least 0.1 wt. %, preferably at least 1 wt. %, more preferably more than 5 wt. % mechanochemically carbonated clay (based on the total weight of the composition), and / or at least 0.1 wt. %, preferably more than 1 wt. %, more preferably more than 20 wt. % additional material (based on the total weight of the composition).

[0114] In embodiments of the present invention, the composition contains less than 60 wt. %, preferably less than 50 wt. %, more preferably less than 45 wt. % mechanochemically carbonated clay (based on the total weight of the composition), and / or less than 95 wt. %, preferably less than 90 wt. %, more preferably less than 80 wt. % additional material (based on the total weight of the composition).

[0115] In embodiments of the present invention, there is provided a composition in which the weight:weight ratio of mechanochemically carbonated clay to additional material is in the range of 1:9 to 2:1, preferably in the range of 1:8 to 1:1, and more preferably in the range of 1:6 to 5:6.

[0116] In embodiments of the present invention, the composition contains 5-70 wt. %, preferably 10-60 wt. %, more preferably 20-50 wt. % mechanochemically carbonated clay (based on the total weight of the composition) and 30-95 wt. %, preferably 40-90 wt. %, preferably 50-80 wt. % additional material (based on the total weight of the composition).

[0117] In embodiments of the present invention, the composition contains less than 5 wt. % water (based on the total weight of the composition), preferably less than 1 wt. %, and more preferably less than 0.1 wt. % water, which can be suitably determined as the mass loss to 120° C. as measured by TGAMS using a temperature trace from room temperature to 800° C. at a rate of 10° C. / min.

[0118] In embodiments of the present invention, the composition comprises a mechanochemically carbonated clay and an additional material.

[0119] In another aspect, the present invention provides a method for making the compositions described herein, comprising: (i) providing a mechanochemically carbonated clay as described herein, preferably a mechanochemically carbonated clay as described herein; (ii) providing an additional material selected from the group consisting of asphalt, cement, geopolymer, polymer, and combinations thereof; and (iii) combining the mechanochemically carbonated clay of step (i) with the material of step (ii); The present invention provides a method comprising:

[0120] Concrete or mortar manufacturing method Thus, in another aspect, the present invention provides a method for producing concrete or mortar, comprising the steps of: (i) providing a mechanochemically carbonated clay as described herein and an additional material selected from the group consisting of asphalt, cement, geopolymer, and combinations thereof, optionally in the form of a composition as described herein, wherein the additional material is selected from the group consisting of asphalt, cement, geopolymer, and combinations thereof; (ii) providing construction aggregates; and (iii) contacting, preferably mixing, the mechanochemically carbonated clay and additional material of step (i) with the construction aggregate and optional water of step (ii); The present invention provides a method comprising:

[0121] In another aspect, the present invention provides a concrete or mortar obtainable by the method for making concrete described herein.

[0122] In a preferred embodiment of the present invention, step (iii) further comprises contacting, preferably mixing, the mechanochemically carbonated clay and additional materials of step (i) with the construction aggregate and water of step (ii). According to the present invention, the mechanochemically carbonated clay and additional materials of step (i) and the construction aggregate and water of step (ii) may be contacted, preferably mixed, substantially simultaneously, or may be contacted, preferably mixed, in a stepwise manner, where the composition of step (i) is first contacted, preferably mixed, with water and then contacted, preferably mixed, with the construction aggregate of step (ii).

[0123] In another aspect, the present invention provides a method for producing a mechanochemically carbonated clay as described herein, 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, geopolymer, 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, To simultaneously improve the strength activity index of concrete and reduce the water demand of concrete; or ·To simultaneously improve the strength activity index of mortar and reduce the water demand of mortar; Provide use. [Example]

[0124] Example The BET surface area (SSA), BJH desorption cumulative surface area of the pores, and desorption average pore width (4V / A by BET) were determined using sample masses of 0.5–1 g at a temperature of 77 K. The samples were heated to 400 °C for the desorption cycle before surface area analysis.

[0125] Particle size distribution and specific surface area measurements were performed on a Brookhaven Laser Particle Sizer, model Microbrook 2000LD, which utilizes Fraunhofer light scattering theory and reports data using the volume-equivalent sphere model.

[0126] Compressive strength, strength activity index, and water demand were measured in accordance with ASTM C311 / C311M-22, and those skilled in the art will appreciate that in performing these tests, a clay precursor or carbonated clay of the present invention was used in place of the "fly ash or natural pozzolan" specified in the standard.

[0127] The CO2 content was determined as the mass loss above 450 °C measured by TGA using a temperature trace where the temperature was increased from room temperature to 800 °C at a rate of 10 °C / min. A Setaram TAG 16 TGA / DSC dual chamber balance was used using 0.1–2 mg samples in an inert nitrogen atmosphere.

[0128] Example 1 Sample A Mechanochemically carbonated clay was produced by placing 0.4 kg of clay precursor (uncalcined clay) in a pressure cell containing 2 kg of primary grinding media (5 mm stainless steel ball bearings) and 5 kg of secondary grinding media (1 mm stainless steel ball bearings). The cell was pressurized with concentrated CO2 gas and rotated on a roller at 65 RPM for 5 days to obtain mechanochemically carbonated clay. The clay precursor was used as received. The reaction was initiated at room temperature and no heating or cooling was performed. The properties of the clay precursor (A1) and the resulting mechanochemically carbonated clay (A2) are shown in the table below.

[0129] Sample B Mechanochemically carbonated clay was produced by placing 5 kg of clay precursor (calcined clay, origin different from Sample A) in a pressure cell containing 150 kg of grinding media (10 mm ceramic bearings). The cell was pressurized with exhaust gas (8-10 vol% CO2, 18-20 vol% H2O, 2-3 vol% O2, 67-72 vol% N2) to an initial pressure of 448 kPa and rotated on a roller at 38 RPM for 3 days to obtain mechanochemically carbonated clay. The clay precursor was used as received. The reaction was initiated at room temperature without heating or cooling. The ceramic bearings had an Al2O3 content of 92 wt% and therefore also functioned as a catalyst. The properties of the clay precursor (B1) and the resulting mechanochemically carbonated clay (B2) are shown in the table below.

[0130] Sample C Mechanochemically carbonated clay was produced by placing 10 kg of clay precursor (calcined clay, origin different from Samples A or B) in a pressure cell containing 100 kg of grinding media (25.4 mm ceramic bearings). The cell was pressurized with exhaust gas (8-10 vol% CO2, 18-20 vol% H2O, 2-3 vol% O2, 67-72 vol% N2) to an initial pressure of 441 kPa and rotated on a roller at 38 RPM for 2 days to obtain mechanochemically carbonated clay. The clay precursor was used as received. The reaction was initiated at room temperature without heating or cooling. The ceramic bearings had an Al2O3 content of 92 wt% and therefore also served as a catalyst. For comparative purposes, a portion of the clay precursor was subjected to conventional milling. The properties of the milled clay precursor (C1) and the resulting mechanochemically carbonated clay (C2) are shown in the table below.

[0131] Sample D Mechanochemically carbonated clay was produced by placing 5 kg of clay precursor (uncalcined clay, same origin as Sample C) in a pressure cell containing 100 kg of grinding media (25.4 mm ceramic bearings). The cell was pressurized with exhaust gas (8-10 vol% CO2, 18-20 vol% H2O, 2-3 vol% O2, 67-72 vol% N2) to an initial pressure of 448 kPa and rotated on a roller at 38 RPM for 2 days to obtain mechanochemically carbonated clay. The clay precursor was used as received. The reaction was initiated at room temperature without heating or cooling. The ceramic bearings had an Al2O3 content of 92 wt% and therefore also served as a catalyst. For comparative purposes, a portion of the clay precursor was subjected to conventional milling. The properties of the milled clay precursor (D1) and the resulting mechanochemically carbonated clay (D2) are shown in the table below.

[0132] Sample E Mechanochemically carbonated clay was produced by placing 1 kg of clay precursor (uncalcined shale raw material) pretreated by calcination (1000 °C) followed by conventional grinding into a pressure cell containing 17.5 kg of grinding media (10 mm ceramic bearings). The cell was pressurized to an initial pressure of 441 kPa with exhaust gas (8-10 vol% CO2, 18-20 vol% H2O, 2-3 vol% O2, 67-72 vol% N2) and rotated on a roller at 38 RPM for 2 days to obtain mechanochemically carbonated clay. The reaction was initiated at room temperature without heating or cooling. The ceramic bearings had an Al2O3 content of 92 wt% and therefore also functioned as a catalyst. The properties of the ground and calcined clay precursor (E1) and the resulting mechanochemically carbonated clay (E2) are shown in the table below.

[0133] [Table 1]

[0134] For sample A, the BET surface areas of the precursor and carbonated materials were 6.6 m, respectively. 2 / g and 24.9m 2 / g, indicating that the majority of the surface area increase provided by the method of the present invention can be attributed to changes in pore surface area.

[0135] As observed from Strength Activity Index (SAI) and water demand measurements, the mechanochemically carbonated clays of the present invention unexpectedly exhibit reduced water demand and increased strength compared to controls of untreated clay, ground clay, calcined clay, and Portland cement.

Claims

1. Mechanochemically carbonated clay obtained by carbonation of a clay precursor and having a specific surface area of less than 50 m ２ / g, wherein CO of the mechanochemically carbonated clay ２ CO content vs. the clay precursor ２ the ratio of the CO content is at least 1.1:1, preferably at least 1.15:1, more preferably at least 1.2:1; ２ The content is determined as the mass loss above 450°C as measured by TGA using a temperature trace in which the temperature is increased from room temperature to 800°C at a rate of 10°C / min; and / or the ratio of the total carbon content of the mechanochemically carbonated clay to the total carbon content of the clay precursor is at least 1.3:1, more preferably at least 1.35:1; Mechanochemically carbonated clay.

2. Features include: D10 in the range of 0.005 to 3 μm, preferably 0.01 to 2 μm, most preferably 0.1 to 1.4 μm; D50 in the range of 0.1 to 30 μm, preferably 0.5 to 15 μm, most preferably 1 to 10 μm; D90 in the range of 0.5 to 100 μm, preferably 1 to 80 μm, most preferably 5 to 70 μm; 2. The mechanochemically carbonated clay of claim 1, having one, two or three, preferably all three, of:

3. More than 0.8 wt. % CO (based on the total weight of the mechanochemically carbonated clay), preferably more than 1 wt. % CO (based on the total weight of the mechanochemically carbonated clay). ２ The CO ２ 3. A mechanochemically carbonated clay according to claim 1 or 2, wherein the content is determined as the mass loss at temperatures above 450°C measured by TGA using a temperature trace in which the temperature is increased from room temperature to 800°C at a rate of 10°C / min.

4. A mechanochemically carbonated clay according to any one of claims 1 to 3, having a total carbon content of at least 0.75% by weight, preferably at least 0.85% by weight, more preferably at least 0.9% by weight.

5. 5. A mechanochemically carbonated clay according to any one of claims 1 to 4, having a Strength Activity Index SAI at 7 days, determined according to ASTM C311 / C311M-22 of at least 105%, preferably at least 110%, more preferably at least 125%, and a Strength Activity Index SAI at 28 days, determined according to ASTM C311 / C311M-22 of at least 110%, preferably at least 115%, more preferably at least 125%.

6. 1. A method for producing mechanochemically carbonated clay, comprising: a) providing a raw material comprising a clay precursor; b) at least 0.5% by volume of CO ２ supplying a gas comprising: c) introducing the raw material and the gas into a mechanical stirring unit; and d) subjecting said raw material to a mechanical stirring operation in said mechanical stirring unit in the presence of said gas; A method comprising:

7. The clay 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 a flue gas, preferably a flue gas 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

10. 10. The method of any one of claims 6 to 9, wherein the feedstock provided in step (a) is a solid feedstock and has a moisture content of less than 30 wt.%, preferably less than 20 wt.%, more preferably less than 15 wt.% (based on the total weight of the solid feedstock).

11. so that the ratio of the total carbon content of the mechanochemically carbonated clay obtained in step (d) to the total carbon content of the clay precursor of step (a) is at least 1.3:1, more preferably at least 1.35:1, and the following characteristics: CO of the mechanochemically carbonated clay obtained in step (d) ２ CO content of the clay precursor in step (a) ２ the ratio of the CO content is at least 1.1:1, preferably at least 1.15:1, more preferably at least 1.2:1, ２ The content is determined as the mass loss above 450°C measured by TGA using a temperature trace where the temperature is increased from room temperature to 800°C at a rate of 10°C / min; the ratio of D50 of the mechanochemically carbonated clay obtained in step (d) to D50 of the clay precursor of step (a) is less than 0.9:1, preferably less than 0.85:1, more preferably less than 0.8:1; the ratio of the specific surface area of the mechanochemically carbonated clay to the specific surface area of the clay precursor is at least 1.15:1, preferably at least 1.2:1, more preferably at least 1.25:1; 11. The method according to any one of claims 6 to 10, wherein the carbonation, size reduction and / or surface area increase during step (d) is effected so as to have one, two or all three of the following, preferably all three:

12. 11. The method according to any one of claims 6 to 10, wherein the mechanochemically carbonated clay obtained in step (d) has a water demand determined according to ASTM C311 / C311M-22 of less than 93%, preferably less than 91%.

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

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

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

16. The mechanochemically carbonated clay 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, geopolymer, 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; - to reduce the expansion of concrete; - for improving the strength activity index of concrete or mortar; and / or - To reduce the water demand of concrete or mortar, Preferably, - to simultaneously improve the strength activity index of concrete and reduce the water demand of the concrete; or - To simultaneously improve the strength activity index of the mortar and reduce the water demand of the mortar; use.

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