USE OF AN ORGANIC ADDITIVE DURING THE GRINDING OF RAW CLAY MATRIX

Abstract

The invention relates to the use of an organic additive during the grinding of at least one raw clay matrix, characterized in that the organic additive comprises a deflocculating polymer having a molecular mass of at least 1000 g / mol and at least three negatively charged groups at a pH greater than 7. The invention also relates to a raw clay matrix ground according to the invention and a construction binder using such clay. Figure to be published with the abstract: Figure 1

Description

Title of the invention: USE OF A ORGANIC ADDITIVE DURING GRINDING FROM A RAW CLAY MATRIX technical field

[0001] The invention relates to the field of construction. In particular, the invention relates to the use of an organic additive during grinding in combination with at least one raw clay matrix. Thus, the invention also relates to a method for preparing a composition for construction binder and a method for preparing a construction binder.

[0002] The invention further relates to a construction binder composition comprising a raw clay matrix that has been ground in the presence of an organic additive according to the invention. The invention also relates to a construction binder and a construction material formed from this ground raw clay matrix. Previous technique

[0003] Cement is the second most consumed resource in the world, with over 4 billion tons produced annually worldwide. This consumption is constantly increasing, driven by the growing demand for housing and infrastructure. Cement is notably used in the manufacture of masonry elements that rely on cementitious materials as binders. Due to the ongoing development of new infrastructure in most countries of the world, there is a continuous demand for the supply of construction binders, particularly raw materials for the production of Portland cement. However, the production and use of Portland cement is associated with a high environmental footprint. The cement used in construction is generally Portland cement. It is a hydraulic binder that, when mixed with water, hardens and sets.After hardening, cement retains its strength and stability, even when exposed to water. A wide variety of cements are used worldwide. However, all conventional cements contain clinker, with the percentage varying from 5% for some blast furnace cements to a minimum of 95% for Portland cement, which is currently the most widely used cement in the world. Clinker is produced by firing a mixture composed of approximately 80% limestone and 20% aluminosilicates (such as clays). This firing process, called clinkerization, is generally carried out at a temperature exceeding 1200°C, making cement production a highly energy-intensive process. Furthermore, the chemical conversion of limestone into lime... It also releases carbon dioxide. As a result, the cement industry generates approximately 8% of global CO2 emissions.

[0004] Indeed, it is estimated that the manufacture of a Portland-type construction binder generates on average 0.8 kg of CO2 per kg of Portland cement clinker produced. Various solutions have therefore been developed to try to replace, at least partially, certain components of the construction binders used in the production of Portland-type cements. These solutions primarily aim to reduce the carbon footprint.

[0005] Until recently, clay was avoided because even low concentrations were sufficient to interact negatively with superplasticizers such as PCEs used in concrete. Thus, in concrete, raw clays were long considered an impurity introduced, for example, by aggregates (e.g., sand). A low clay content inhibits the effect of plasticizers and superplasticizers and negatively impacts the water demand of concrete. This leads to a significant increase in the amount of water required to achieve a given flow rate, resulting in a loss of mechanical performance in the hardened product. However, it has recently been shown that preparing construction binders from raw clay, added even before the addition of fillers, can enable the generation of construction materials with high levels of mechanical strength (WO22157209, EP3932886, WO20178538, WO20141285).

[0006] New methods using clay have been proposed to improve the mechanical properties of clay-based construction materials while maintaining a low carbon footprint. For example, international patent application WO2022 / 200284 proposes using a milling additive during the grinding of clay with a clay matrix, preferably one that has undergone heat treatment between 500 and 1200°C. However, this solution remains unsatisfactory because the clay used is heat-treated, thus increasing its environmental impact. Furthermore, the proposed materials exhibit a maximum compressive strength at 28 days of 12.6 MPa, which does not meet industry requirements.

[0007] Since then, new construction binders and materials containing a significant amount of raw clay have been under development, making it possible to achieve considerably reduced carbon footprints. However, in order to promote their widespread adoption, these low-carbon solutions must exhibit high early-age mechanical strength so that industrial processes can replace Portland cement with these low-carbon solutions without adverse effects.

[0008] Thus, there is a need for new raw clay-based building materials with improved mechanical properties at an early age (i.e. within the first 24 hours or after a few hours). Summary of the invention

[0009] The invention aims to overcome these drawbacks. The following presents a simplified summary of selected aspects, embodiments, and examples of the present invention in order to provide a basic understanding of the invention. However, this summary does not constitute an exhaustive overview of all aspects, embodiments, and examples of the invention. Its sole purpose is to present selected aspects, embodiments, and examples of the invention in a concise form as an introduction to the more detailed description of the aspects, embodiments, and examples of the invention that follows the summary.

[0010] The invention relates in particular to the use of an organic additive during the grinding of at least one raw clay matrix, characterized in that the organic additive comprises a deflocculating polymer having a molecular mass of at least 1000 g / mol and at least 3 negatively charged groups at a pH greater than 7.

[0011] The applicant has selected an organic additive capable, when used during the grinding of a raw clay matrix, of improving the performance of the boryized raw clay matrix used for the manufacture of a construction binder and subsequently a construction material. In particular, it improves the shrinkage performance of a construction material using this ground raw clay matrix according to the invention.

[0012] Depending on other optional features of the use of the organic additive, the latter may optionally include one or more of the following features, alone or in combination: - the deflocculant polymer has a molecular mass of at least 2000 g / mol, preferably at least 5000 g / mol, more preferably at least 9000 g / mol, even more preferably at least 14000 g / mol, for example at least 22000 g / mol; - the deflocculant polymer has at least 5, preferably at least 7, more preferably at least 9, even more preferably at least 10 negatively charged groups at a pH greater than 7; - negatively charged groups at a pH greater than 7 are sulfonate and / or carboxylate groups, preferably sulfonates; the deflocculant polymer has a molecular mass to number of negatively charged groups ratio at a pH greater than 7, less than or equal to 2000; the deflocculant polymer has a molecular mass to number of negatively charged groups ratio at a pH greater than 7, is greater than or equal to 200; the deflocculant polymer has a polydispersity index of less than 5, preferably less than 4 and more preferably less than 3; the deflocculant polymer comprises one or more poly(oxyethylene) or poly(oxypropylene) chains, the poly(oxyethylene) or poly(oxypropylene) chains having a molecular mass of at least 200 g / mol; the deflocculant polymer has a ratio of at least 2:1 between the number of sulfonate functions and the number of uncharged side chains; The deflocculant polymer was formed from monomers containing a melamine sulfonate group; more preferably, the main chain of the deflocculant polymer comprises melamine sulfonate groups linked by covalent bonds; even more preferably, the main chain of the deflocculant polymer comprises a repeated sequence of melamine sulfonate nuclei linked by covalent bonds. the grinding is a dry grinding, that is to say that during grinding the raw clay matrix has a water content of less than or equal to 5%; preferably less than or equal to 3%, more preferably less than or equal to 2%, even more preferably less than or equal to 1%. the grinding additive is added in the form of a powder, a solution or a sprayed suspension onto the raw clay matrix at the grinding input; the grinding additive also contains alkanolamines and / or triethanolamines such as triisopropanolamine (TIPA), triethanolamine (TEA), and diethanolisopropanolamine (DEIPA); the grinding is carried out on one or more raw clay matrices and at least one raw clay matrix contains nodules of material with a MOHS hardness greater than or equal to 5, preferably greater than 5. This typically corresponds to the presence of quartz or feldspar nodules. The grinding is carried out on several raw clay matrices, and at least one raw clay matrix contains nodules of material with a MOHS hardness greater than or equal to 5, preferably greater than 5 (this typically corresponds to the presence of quartz or feldspar nodules), while at unless a raw clay matrix contains no nodules of material with a MOHS hardness greater than or equal to 5. - The organic additive is added to a first raw clay matrix, and then said first raw clay matrix is ​​co-ground with another raw clay matrix. Alternatively, or in combination, the organic additive is added to a first raw clay matrix, and then said first raw clay matrix is ​​co-ground with other constituents of the construction binder, such as one or more activators and / or one or more precursors.

[0013] According to another aspect, the invention relates to a ground raw clay matrix obtained following use according to the invention. In particular, it relates to a ground raw clay matrix having a D10 of between 3 and 9 pm, a D50 of between 15 and 250 pm, and a D90 of between 110 and 180 pm (inclusive).

[0014] According to another aspect, the invention relates to a method for manufacturing a construction binder comprising: - a grinding step of a raw clay matrix in the presence of an organic additive, the organic additive comprising a deflocculating polymer having a molecular mass of at least 1000 g / mol and at least 3 negatively charged groups at a pH greater than 7; - a step of mixing the crushed raw clay matrix with other constituents of the construction binder, for example mixing with at least one precursor and / or mixing the crushed raw clay matrix with at least one activator.

[0015] In another aspect, the invention relates to a construction binder obtainable by a construction binder manufacturing process according to the invention. In particular, the invention relates to a construction binder comprising a raw clay matrix ground according to the invention, as well as one or more activators and / or one or more precursors. Preferably, said raw clay matrix ground according to the invention having a particle size profile as described below. Brief description of the drawings

[0016] Other features and advantages of the invention will be better understood from the following description and with reference to the accompanying drawings, given by way of illustration and not limitation.

[0017] [Fig.1] Fig.1 represents a schematic illustration of a process for manufacturing a construction binder composition according to an embodiment of the present invention.

[0018] [Fig. 2] [Fig. 2] represents a schematic illustration of a process for manufacturing a construction material according to an embodiment of the present invention. Description of embodiments

[0019] Below, we describe a summary of the invention and the associated vocabulary, before presenting the disadvantages of the prior art, and finally showing in more detail how the invention remedies them.

[0020] The term “binder” or “construction binder” in the context of the invention can be understood as a formulation that ensures the agglomeration of materials, particularly during the setting and subsequent hardening of a construction material. Thus, it specifically ensures the agglomeration of sand and other constituents of the construction material with the constituents of the binder. The binder according to the invention is, in particular, a hydraulic binder, meaning that hardening occurs upon contact with water.

[0021] The term "clay matrix," as used in the invention, may refer to one or more rock materials based on hydrated silicates or aluminosilicates with a lamellar structure, said clay matrix being composed of fine particles generally resulting from the alteration of silicates with a three-dimensional framework, such as feldspars. A clay matrix may thus comprise a mixture of such rock materials, which may, for example, consist of kaolinite, illite, smectite, bentonite, chlorite, vermiculite, or mixtures thereof. Furthermore, a clay matrix may include silts.

[0022] For the purposes of this invention, the term "raw clay matrix" may refer to a clay matrix that has not undergone a calcination step. Thus, it may also be called an uncalcined clay matrix. For example, this corresponds to a clay matrix that has not been subjected to a temperature rise exceeding 300°C, preferably exceeding 200°C, and more preferably exceeding 150°C. Indeed, the raw clay matrix may undergo a heating-drying step requiring a temperature rise generally equal to or less than 150°C, but no calcination step. A raw clay matrix may preferably comprise a mixture of rock materials, which may, for example, include kaolinite, illite, smectite, micas such as muscovite, bentonite, chlorite, vermiculite, or mixtures thereof, as well as silts.

[0023] In the following description, the term "% by weight" in relation to the binder composition, the binder itself, or the construction material, shall be understood as a proportion relative to the dry weight of the composition, the binder, or the construction material, respectively. The dry weight may, for example, correspond to the weight before the addition of water, for example, necessary for the Construction material formation. When % weight values ​​are given as ranges, the bounds are included unless otherwise specified.

[0024] For the purposes of this invention, a "flocculant" can refer to a compound capable of dissociating aggregates and colloids, particularly those in aqueous suspension. Flocculant agents have, for example, been used in drilling or oil extraction to make clay more fluid and facilitate extraction or drilling. The term "organic deflocculant" can refer to a deflocculant comprising at least one carbon atom and preferably at least one carbon-oxygen bond. The term "polymer deflocculant" can, for the purposes of this invention, refer to a deflocculant agent comprising at least one repeating monomer.

[0025] The term "monomer" corresponds, in the sense of the invention, to a molecule or chemical compound that can assemble repeatedly to form a larger polymeric structure.

[0026] The term "oligomer" corresponds, in the sense of the invention, to a molecule or a chemical compound formed by the bonding of at least two monomers, but with a number of repetitions less than that required to be considered a polymer.

[0027] The term “polymer” refers, in the context of this invention, to a macromolecule composed of numerous identical monomer units chemically bonded to one another repeatedly, thus forming a large structure with a high molecular weight. For example, a polymer may comprise at least 10 monomers.

[0028] For the purposes of this invention, a "main chain," also referred to as a backbone, can correspond to the continuous sequence of covalent bonds linking the monomers together to form the polymer. This linear or sometimes branched structure constitutes the framework of a polymer, upon which the various physical, chemical, and mechanical properties of the material are based.

[0029] For the purposes of this invention, a "side chain" of a polymer can correspond to the functional groups or polymer segments that are attached to the main chain but are not an integral part of the repeating sequence of monomers constituting the main backbone. These side chains can vary in length, chemical structure, and functionality.

[0030] For the purposes of the invention, the expression "melamine core" can correspond to a molecular fragment derived from melamine, a trimeric organic compound with the molecular formula C3H6N6. Thus, a melamine core generally comprises a triazine ring that can be substituted.

[0031] For the purposes of the invention, the expression "melamine sulfonate" may correspond to a functionalized derivative of melamine where one or more sulfonate groups (-SO3- ) are linked directly or indirectly to the nitrogen of the amine groups of the melamine molecule.

[0032] The terms "group", "functional group" or "chemical group" correspond to the meaning of the invention and are a set of atoms linked in a molecule which confers specific properties and reactivities to that molecule.

[0033] The term "negatively charged group" corresponds, in the sense of the invention, to a group comprising at least one atom which has at least one negative charge due to the presence of additional ions or electrons.

[0034] For the purposes of this invention, the expression "average molar / molecular mass" can refer to a statistical measurement of the average mass of molecules in a sample of a polymer. Preferably, for the purposes of this invention, the average molecular mass corresponds to the average molecular mass by weight (Mw). It is preferably measured according to the specifications of ISO 16014:2019.

[0035] The term "D50" corresponds to the median diameter for which 50% (by volume or mass, preferably by mass) of the grains, particles, aggregates, or sediments are smaller than a given diameter. For example, if a sieving and sedimentation analysis method indicates a D50 of 5.8 mm, then 50% of the particles in the sample (by volume or mass, preferably by mass) are larger than 5.8 mm. D50 is generally used to represent the particle size of a group of particles. D50 is preferably measured according to ASTM D422-63 or ASTM D6913-04(2009), or, in particular for fine particles, ISO 13320:2020 (e.g., D10 or <65 µm).The terms "particle size distribution," "particle size profile," or "particle size distribution" can refer to parameter values ​​related to particle size distribution, for example, in raw clay matrix or raw soil. Many parameters relate to particle size distribution, such as D50, D10, and D90.

[0036] The term "substantially equal" in the meaning of the invention corresponds to a value varying by less than 20% from the compared value, preferably by less than 10%, even more preferably by less than 5%.

[0037] The construction industry must evolve its concrete manufacturing processes in order to offer concretes

[0038] The invention proposes using an organic additive during the grinding of a raw clay matrix intended for use in a construction binder. Indeed, the applicant has discovered, surprisingly, that the use of an organic additive, preferably comprising a deflocculating polymer with specific characteristics, during the grinding step with a raw clay matrix makes it possible to obtain a construction material with improved shrinkage properties.

[0039] Thus, the invention relates to the use of an organic additive during grinding with at least one raw clay matrix. The use of an organic additive comprising a deflocculating polymer with particular characteristics allows, for example, the formation of an improved construction binder and construction materials incorporating this binder with improved shrinkage properties.

[0040] According to a first aspect, the invention relates to the use of an organic additive during the grinding of at least one raw clay matrix. Preferably, the organic additive comprises a deflocculating polymer, said deflocculating polymer having a molecular mass of at least 1000 g / mol and at least 3 negatively charged groups at a pH greater than 7. Organic additive

[0041] Advantageously, an organic additive used according to the present invention comprises at least one deflocculating polymer. Furthermore, an organic additive may comprise at least one other organic or inorganic compound other than the at least one deflocculating polymer, as will be described below. deflocculating polymer

[0042] The use of one or more deflocculant(s) can improve the performance of the material formed from the raw clay matrix thus ground.

[0043] A deflocculant polymer used according to the invention may have a molecular mass of at least 1000 g / mol, preferably at least 2000 g / mol, more preferably at least 5000 g / mol, even more preferably at least 9000 g / mol, and even more preferably at least 14000 g / mol. For example, the deflocculant polymer used may have a molecular mass of at least 22000 g / mol.

[0044] The deflocculant polymer used may have at least 5 negatively charged groups, preferably at least 7 negatively charged groups, more preferably at least 9 negatively charged groups, even more preferably at least 10 negatively charged groups.

[0045] Preferably, the negatively charged groups of the deflocculant polymer used can be selected from sulfonate and / or carboxylate groups, preferably sulfonates.

[0046] Furthermore, the deflocculant polymer used may comprise one or more poly(oxyethylene) or poly(oxypropylene) chains. Preferably, these poly(oxyethylene) and poly(oxypropylene) chains have a molecular mass of at least 200 g / mol. These side chains may have a molecular mass of at least 300 g / mol, for example, at least 500 g / mol.

[0047] The deflocculant polymer used may comprise one or more side chains bearing unsaturations. Thus, the polymer used may comprise side chains having at least one unsaturation, preferably at least two unsaturations.

[0048] Preferably, the deflocculating polymer may have been formed from monomers that may include a melamine sulfonate group.

[0049] Advantageously, the deflocculating polymer may have a ratio between its molecular mass and its number of negatively charged groups less than or equal to 2000, preferably less than or equal to 1800, more preferably less than or equal to 1600 and even more preferably less than or equal to 1400. Indeed, this is particularly advantageous when used with raw clay matrices.

[0050] Advantageously, the deflocculating polymer has a ratio of its molecular mass to its number of negatively charged groups at a pH greater than 7, greater than or equal to 200, preferably greater than or equal to 220, more preferably greater than or equal to 240, and even more preferably greater than or equal to 260. Indeed, this is particularly advantageous when used with raw clay matrices.

[0051] In addition, the deflocculating polymer may have a polydispersity index of less than 5, preferably less than 4 and more preferably less than 3.

[0052] Advantageously, the deflocculating polymer has sulfonate functions. Furthermore, the deflocculating polymer may have a ratio of at least 2:1 between the number of sulfonate functions and the number of uncharged side chains.

[0053] Preferably, the deflocculant polymer comprises monomers containing a melamine core, said deflocculant polymer having a main chain formed of a repeating sequence in which the melamine cores are linked together by covalent bonds. The deflocculant polymer may also comprise monomers containing a naphthalene core, said deflocculant polymer having a main chain formed of a repeating sequence in which the naphthalene cores are linked together by covalent bonds. Thus, the deflocculant polymer may be selected from polymelamine sulfonate or polynaphthalene sulfonate, with a density of at least 1000 g / mol and comprising at least 3 negatively charged groups at a pH greater than 7. Other organic compound

[0054] An organic additive used according to the invention may further comprise at least one other organic compound, which would not be a deflocculating polymer according to the invention.

[0055] For example, at least one other compound used in the organic additive may be selected from alkanolamines, glycols, glycerol, sugars, sugar acids, carboxylic acids or their salts, superabsorbent polymers, or a mixture thereof.

[0056] For example, the alkanolamines used according to the invention can be selected from monoethanolamine, diethanolamine, triethanolamine (TEA), diethanolisopropanolamine (DEIPA), ethanoldiisopropanolamine (EDIPA), isopropanolamine, diisopropanolamine, triisopropanolamine (TIPA), N-methyldiisopropanolamine (MDIPA), N-methyldiethanolamine (MDEA), tetrahydroxyethylethylenediamine (THEED), tetrahydroxyisopropylethylenediamine (THIPD), as well as mixtures of two or more of these alkanolamines.

[0057] Preferably, the alkanolamines used according to the invention can be selected from: triisopropanolamine (TIPA), N-methyldiisopropanolamine (MDIPA), N-methyldiethanolamine (MDEA), tetrahydroxyethylethylenediamine (THEED), diethanolisopropanolamine (DEIPA), tetrahydroxyisopropyl ethylenediamine (THIPD), as well as mixtures of two or more of these alkanolamines.

[0058] More preferably, an organic additive may further comprise alkanolamines selected from triethanolamines such as triisopropanolamine (TIPA), triethanolamine (TEA), and / or diethanolisopropanolamine (DEIPA).

[0059] Examples of suitable glycols for the organic additive are monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, polyethylene glycol (e.g., PEG 200), neopentyl glycol, hexylene glycol, propylene glycol, dipropylene glycol, and polypropylene glycol. It is also possible to use mixtures of two or more different glycols, as well as at least one glycol and glycerol.

[0060] Examples of sugars that can be incorporated into the organic additive used during milling include monosaccharides and disaccharides. Suitable examples include allose, altrose, arabinose, cellobiose, chitobiose, fructose, galactose, glucose, glyceraldehyde, gulose, idose, isomaltose, lactose, lactulose, lyxose, maltose, mannobiose, mannose, palatinose, raffinose, ribose, sucrose, sorbose, tallose, threose, trehalose, xylose, xylobiose, and mixtures thereof.

[0061] In the context of the present invention, a "sugar acid" is a monosaccharide possessing a carboxyl group. Examples of sugar acids useful in the context of the present invention include, but are not limited to, ascorbic acid, galacturonic acid, gluconic acid, glucuronic acid, glyceric acid, iduronic acid, mucic acid, neuramine, saccharic acid, tartaric acid, and xylonic acid. The sugar acid may be in the form of a free acid or a salt.

[0062] Carboxylic acids that can be used in the organic additive in combination with the deflocculating polymer and are particularly preferred are acid Oxalic acid, malonic acid, adipic acid, lactic acid, citric acid, and tartaric acid. Carboxylic acid can exist as a free acid or as a salt.

[0063] According to some embodiments, the sugar acid salts and / or carboxylic acid salts may be salts with metals from groups Ia, Ia, Ib, IIb, IVb, VIIIb of the periodic table of elements. Preferred sugar acid salts and / or carboxylic acid salts are salts of alkali metals, alkaline earth metals, iron, cobalt, copper, or zinc.

[0064] Examples of superabsorbent polymers useful in the context of the present invention include, but are not limited to, natural polymers such as starch, cellulose (including cellulose ether), chitin or collagen, alginates, and synthetic polymers such as poly(hydroxyethyl methacrylate), poly(ethylene glycol) or poly(ethylene oxide) or ionic synthetic polymers such as polyacrylic acid (PAA), polymethacrylic acid (PMAA), polyacrylamides (PAM), polylactic acid (PLA), polyethyleneimine, polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP).

[0065] Superabsorbent polymers particularly suitable within the framework of the present invention are ionic superabsorbent polymers, in particular those based on polyacrylamide modified with acrylic acid, which can be of linear or cross-linked structure.

[0066] Advantageously, an organic additive according to the invention comprises at least 70% by dry weight of a deflocculant polymer, preferably at least 75% by dry weight of a deflocculant polymer, and more preferably at least 80% by weight of a deflocculant polymer. An organic additive according to the invention comprises 100% by dry weight of a deflocculant polymer, preferably up to 95% by dry weight of a deflocculant polymer, and more preferably up to 90% by weight of a deflocculant polymer. An organic additive according to the invention comprises from 70% to 100% by dry weight of a deflocculant polymer, preferably from 75% to 95% by dry weight of a deflocculant polymer, and even more preferably from 80% to 90% by weight of a deflocculant polymer.

[0067] An organic additive used according to the invention comprises 0% by weight of at least one other organic or inorganic compound, preferably at least 5% by weight of at least one other organic or inorganic compound, and more preferably at least 10%. An organic additive used according to the invention comprises at most 30% by weight of at least one other organic or inorganic compound, preferably at most 25% by weight of at least one other organic or inorganic compound, and more preferably at most 20%. An organic additive used according to the invention comprises from 0% to 30% by weight of at least one other organic or inorganic compound, preferably from 5% to 25% by weight of at least one other organic or inorganic compound and more preferably from 10% to 20%.

[0068] Organic additives are added to the raw clay matrix before and / or during grinding in a total quantity of between 0.001 and 3% by weight, preferably between 0.002 and 1% by weight, and more preferably between 0.01 and 0.1% by weight, in each case relative to the total dry weight of the raw clay matrix. Raw clay matrix

[0069] As mentioned previously, the invention relates to the use of an organic additive during the grinding of a raw clay matrix.

[0070] The raw clay matrix used may, for example, comprise at least one mineral species selected from: Illite, Kaolinite, Smectite, Bentonite, Vermiculite, Chlorite, Montmorillonite, Muscovite, Halloysite, Sepiolite, and Attapulgite. For example, the raw clay matrix may comprise at least 5%, preferably at least 15%, and even more preferably at least 20% by weight of a mineral species selected from: Illite, Kaolinite, Smectite, Bentonite, Vermiculite, Chlorite, Montmorillonite, Muscovite, Halloysite, Sepiolite, and Attapulgite.

[0071] Preferably, the raw clay matrix used may comprise at least two types of clay selected from: Illite, Kaolinite, Smectite, Bentonite, Vermiculite, Chlorite, Montmorillonite, Muscovite, Halloysite, Sepiolite, and Attapulgite. This includes so-called interstratified clays, which are complex combinations of several clays. Even more preferably, the raw clay matrix comprises at least one mineral species selected from: Kaolinite, Illite, Smectite, Bentonite, Chlorite, Montmorillonite, and Vermiculite.

[0072] Table 1 below presents the chemical characteristics of these mineral species. [Tables 1] Matrix A clayey C rue Type of clay Composition Illite (K,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] Smectite (Na,Ca)o,3(Al,Mg)2Si4010(OH)2, n H2O Kaolinite Al2Si2O5(OH)4 Bentonite (Na,Ca)o.3(Al,Mg)2Si4010(OH)2 Vermiculite (Mg,Ca)o,7(Mg,Fe,Al)6(Al,Si)8°22(OH)4nH20 Chlorite (Fe,Mg,Al)6(Si,Al)4°10(OH)8 Muscovite KAl2(AlSi3O10) (OH,F)2 Halloysite Al2Si2O5(OH)4 Sepiolite Mg4Si6O15(OH)2, n H2O Attapulgite (Mg,Al,Fe3+)5[Si8O20](OH)2 (OH2)4n H2O

[0073] According to a preferred mode, the raw clay matrix used comprises at least two different types of clays and will include smectite (Smectite, Bentonite, Montmorillonites), kaolinite, and / or illite.

[0074] In particular, a raw clay matrix according to the present invention may comprise at least 25% kaolinite and / or illite. Raw clay matrices comprising a majority of kaolinite and / or illite are preferred within the scope of the present invention. This may, for example, correspond to a clay matrix comprising more than 25% kaolinite and more than 25% illite, or a clay matrix comprising more than 40% kaolinite and more than 10% illite. Thus, a raw clay matrix according to the present invention will preferably comprise at least 50% by dry weight of kaolinite and / or illite, and more preferably at least 70% by dry weight of kaolinite and / or illite.

[0075] The raw clay matrix may contain a CaO content greater than or equal to 2%. Preferably, the raw clay matrix contains a CaO content greater than or equal to 4%, more preferably greater than or equal to 6%, even more preferably greater than or equal to 8%, for example greater than or equal to 10%. The CaO content can be measured, for example, by X-ray diffraction, X-ray fluorescence spectrometry, or atomic absorption spectrometry.

[0076] The raw clay matrix may have a K2O content of 5% or less. Preferably, the raw clay matrix has a K2O content of 3% or less, more preferably 2% or less, and even more preferably 1.5% or less. The K2O content can be measured, for example, by X-ray diffraction, X-ray fluorescence spectrometry, or atomic absorption spectrometry.

[0077] The raw clay matrix may contain an amount of Na2O less than or equal to 2%. Preferably, the raw clay matrix contains an amount of Na2O less than or equal to 1.5%, more preferably less than or equal to 1%, and even more preferably less than or equal to 0.5%. The amount of Na2O is measured, for example, by X-ray diffraction, X-ray fluorescence spectrometry, or atomic absorption spectrometry.

[0078] The raw clay matrix may have a SiO2 content greater than or equal to 30%. Preferably, the raw clay matrix has a SiO2 content greater than or equal to 35%, more preferably greater than or equal to 40%, even The preferred concentration is greater than or equal to 45%, for example greater than or equal to 48%. The amount of SiO2 is measured, for example, by X-ray diffraction, X-ray fluorescence spectrometry, or atomic absorption spectrometry.

[0079] More preferably, the raw clay matrix used according to the invention comprises nodules of material with a high hardness, generally composed of quartz or feldspars, having a hardness greater than or equal to 5 on the Mohs scale.

[0080] The nodules can be qualified (measured by their hardness) and quantified using scanning electron microscopy (SEM), X-ray diffraction (XRD), or micro-computed tomography (Micro-CT). Thus, a clay particularly suited to the invention can be selected based on its mineralogical composition. It will be characterized in particular by the presence of quartz and / or feldspar nodules with high hardness. For example, the presence of nodules with a Mohs hardness greater than or equal to 5, preferably greater than or equal to 6. Indeed, the inventors have shown that the presence of nodules with such hardness in the clay matrix, combined with the use of an organic additive according to the invention, allows for a reduction in the energy allocated to grinding and the quantity of organic additive, while maintaining equivalent performance of the construction binder.This leads to a construction binder with an even lower carbon footprint.

[0081] The type of clay can be determined by methods known to a person skilled in the art. In particular, X-ray diffractometry can be used. For example, the following conditions can be used:

[0082] - Apparatus: Diffractometer, for example a BRUKER D8 ADVANCE® (Bragg-Brentano geometry); for example, with the following settings: Copper Tube (X Kal ~ 1.54 Å); Generator power: 40 kV, 40 mA; Primary optics: fixed slit 0.16°; Soller slit 2.5°; Secondary optics: Soller slit 2.5°; LynXeye XE-T® detector

[0083] - Acquisition parameters: Scanning from 4 to 90°20; Scanning speed of 0.03°20 / second, Counting time: 480 seconds per step; Rotating sample.

[0084] Preferably, the raw clay matrix used in the context of the invention comprises at least 20% by weight of Smectite, Illite, and / or Kaolinite, for example, at least 30% by weight of Smectite, Illite, and / or Kaolinite, preferably at least 40% by weight of Smectite, Illite, and / or Kaolinite, more preferably at least 50% by weight of Smectite, Illite, and / or Kaolinite, and even more preferably at least 60% by weight of Smectite, Illite, and / or Kaolinite. The weight percentage corresponds to the cumulative percentage of Smectite, Illite, and Kaolinite.

[0085] In particular, a clay matrix according to the invention may comprise between 20 and 80% by weight of Smectite, Illite and / or Kaolinite, preferably between 30 and 70% by weight of Smectite, Illite and / or Kaolinite, or between 40 and 60% by weight of Smectite, Illite and / or Kaolinite, preferably between 40 and 60% by weight of Smectite, Illite and / or Kaolinite. Preferably, the Smectite may be Montmorillonite.

[0086] Advantageously, the raw clay matrix used for grinding may comprise at least 2% by weight of silt particles, preferably at least 4% by weight, and more preferably at least 6% by weight. For example, the raw clay matrix may comprise at most 50% by weight of silt particles, preferably at most 30% by weight, and more preferably at most 20% by weight. The silt particles are, in particular, particles having a diameter between 2 µm and 200 µm.

[0087] The raw clay matrix used for grinding may contain at least 1% by weight of sand, preferably at least 2% by weight, and more preferably at least 3% by weight. For example, the raw clay matrix may contain at most 70% by weight of sand, preferably at most 50% by weight, and more preferably at most 40% by weight. For example, the raw clay matrix used may contain from 1% to 70% by weight of sand particles, preferably from 2% to 50% by weight, and more preferably from 3% to 40% by weight. The sand corresponds in particular to particles having a diameter between 63 µm and 2 mm.

[0088] The raw clay matrix used for grinding can preferably correspond at least in part to excavated clay soil, preferably uncalcined excavated clay soil, such as treated raw excavated clay soil.

[0089] At least one raw clay matrix is ​​ground in the presence of the organic additive, and advantageously, at least two raw clay matrices can be ground in the presence of the organic additive. Thus, within the scope of the invention, at least two raw clay matrices with different particle size profiles are used for grinding. For example, a first raw clay matrix and a second raw clay matrix may have two distinct D50 values. For example, the first raw clay matrix may have a D50 greater than 1000 µm and a second raw clay matrix may have a D50 less than 1000 µm. Preferably, the first raw clay matrix may have a D50 greater than 1000 µm and a second raw clay matrix may have a D50 less than 500 µm.Preferably, the first raw clay matrix may have a D50 greater than 800 pm and a second raw clay matrix may have a D50 less than 400 pm. Preferably, the first raw clay matrix may have a D50. one greater than 400 pm and a second raw clay matrix may have a D50 less than 400 pm.

[0090] As described above, the raw clay matrix is ​​ground with an organic additive, said organic additive comprising at least one deflocculating polymer. It should be noted that the raw clay matrix used may have undergone other treatment selected from: sorting, sieving, and / or drying. Advantageously, the grinding can be carried out with a mill or crusher such as, for example, a hammer mill, a ball mill, or a rod mill.

[0091] Thus, according to another aspect, the invention relates to a ground raw clay matrix. This ground raw clay matrix was ground in the presence of an organic additive comprising a deflocculating polymer having a molecular mass of at least 1000 g / mol and at least 3 negatively charged groups at a pH greater than 7.

[0092] This crushed raw clay matrix comprising an organic additive according to the invention can have a particle size profile particularly suitable for the preparation of a construction binder. The particle size profile is measured by D50, which is preferably measured according to ASTM D422-63 or ASTM D6913-04(2009), or, in particular for fine particles, according to ISO 13320:2020 (e.g., D10 or <65 pm).

[0093] In particular, the ground raw clay matrix comprising an organic additive according to the invention may have a D90 of 200 pm or less. Preferably, a D90 of 180 pm or less, more preferably a D90 of 160 pm or less, and even more preferably a D90 of 150 pm or less. The ground raw clay matrix comprising an organic additive according to the invention may have a D90 of 100 pm or more. Preferably, a D90 of 110 pm or more, more preferably a D90 of 115 pm or more, and even more preferably a D90 of 120 pm or more. The ground raw clay matrix comprising an organic additive according to the invention may have a D90 ranging from 100 to 200 pm. Preferably, a D90 ranging from 110 to 180 pm, more preferably a D90 ranging from 115 to 160 pm, and more preferably a D90 ranging from 120 to 150 pm.

[0094] In particular, the crushed raw clay matrix comprising an organic additive according to the invention may have a D50 less than or equal to 500 pm. Preferably, a D50 less than or equal to 400 pm, more preferably a D50 less than or equal to 250 pm, and more preferably a D50 less than or equal to 100 pm or even more preferably less than or equal to 50 pm, more preferably less than or equal to 45 pm.

[0095] The crushed raw clay matrix comprising an organic additive according to the invention may have a D50 greater than or equal to 5 pm. Preferably, a D50 greater than or equal to 10 pm, more preferably a D50 greater than or equal to 15 pm, and Preferably, a D50 greater than or equal to 20 pm, and even more preferably greater than 40 pm. This helps to limit the stress on industrial production equipment dedicated to grinding.

[0096] The crushed raw clay matrix comprising an organic additive according to the invention can have a D50 ranging from 10 to 500 µm. Preferably, a D50 ranging from 15 to 250 µm, more preferably a D50 ranging from 20 to 150 µm, and even more preferably a D50 ranging from 20 to 50 µm. The presence of clay crushed to achieve such diameters can improve the performance of the construction binder and the construction material according to the invention.

[0097] In particular, the ground raw clay matrix comprising an organic additive according to the invention may have a D10 less than or equal to 10 pm. Preferably, a D10 less than or equal to 9 pm, more preferably a D10 less than or equal to 8 pm, and even more preferably a D10 less than or equal to 7 pm. The ground raw clay matrix comprising an organic additive according to the invention may have a D10 greater than or equal to 2 pm. Preferably, a D10 greater than or equal to 3 pm, more preferably a D10 greater than or equal to 4 pm. The ground raw clay matrix comprising an organic additive according to the invention may have a D10 ranging from 2 to 10 pm. Preferably, a D10 from 3 to 9 pm, more preferably a D10 from 4 to 8 pm, and more preferably a D10 from 4 to 7 pm.

[0098] The raw clay matrix ground according to the invention is particularly suitable for manufacturing a composition for a construction binder or for manufacturing a construction binder. Advantageously, as illustrated in the examples, the raw clay matrix ground according to the invention has a D10 ranging from 3 to 9 µm, a D50 ranging from 15 to 250 µm, and a D90 ranging from 110 to 180 µm. Preferably, the raw clay matrix ground according to the invention has a D10 ranging from 4 to 8 µm, a D50 ranging from 20 to 150 µm, and a D90 ranging from 115 to 160 µm. Even more preferably, the raw clay matrix ground according to the invention has a D10 ranging from 4 to 7 pm, a D50 ranging from 20 pm to 50 pm and a D90 ranging from 120 to 150 pm.

[0099] Thus, according to another aspect, the invention relates to a construction binder composition comprising the raw clay matrix ground according to the invention. In particular, the invention relates to a construction binder comprising the raw clay matrix ground according to the invention.

[0100] To form a construction binder, the raw clay matrix ground according to the invention can be supplemented in particular by at least one precursor and / or at least one activator.

[0101] Thus, a binder composition according to the invention may comprise, in addition to the ground raw clay matrix: one or more precursors, one or more activators, a or several fillers, one or more additives such as air-entraining agents, retarders, accelerators, shrinkage-reducing admixtures, and / or viscosity-modifying admixtures.

[0102] In particular, the construction binder composition according to the invention may comprise one or more precursors and / or one or more activators. Preferably, a construction binder according to the invention may comprise one or more precursors and one or more activators.

[0103] Thus, according to another aspect, the invention relates to a construction material obtained from a composition according to the invention and more particularly from a construction binder according to the invention.

[0104] In particular, the present invention relates to a construction material characterized in that it comprises a ground raw clay matrix. This ground raw clay matrix was ground in the presence of an organic additive comprising a deflocculating polymer having a molecular mass of at least 1000 g / mol and at least 3 negatively charged groups at a pH greater than 7.

[0105] Preferably, the construction material comprises at least 10% by dry weight of raw clay matrix ground according to the invention relative to the dry weight of the construction binder.

[0106] Aggregates

[0107] A construction material according to the present invention may comprise aggregates.

[0108] Classically, aggregates can correspond to natural aggregates, artificial aggregates or recycled aggregates.

[0109] Aggregates may also include mineral aggregates, i.e., mainly composed of mineral matter, and / or plant aggregates, i.e., mainly composed of matter of plant origin. Aggregates may also include marine aggregates, i.e., mainly composed of organic or inorganic matter from the seabed, such as siliceous aggregates and / or calcareous substances (e.g., maerl and shell sands).

[0110] Mineral aggregates can, for example, correspond to sand, gravel, pebbles, fillers (or fine materials), powders, fossilized waste and combinations thereof.

[0111] Plant aggregates may, for example, consist of wood (chips or fibers), hemp, straw, hemp shives, miscanthus, sunflower, cattail, maize, flax, rice husks, wheat husks, rapeseed, seaweed, bamboo, cellulose wadding, defibrated fabric and combinations thereof

[0112] In particular, when the building material according to the invention comprises plant aggregates, said material preferably comprises at least 0.1% by weight of plant aggregates, preferably at least 0.2% by weight of plant aggregates, more preferably at least 0.5% by weight of plant aggregates, and even more preferably at least 0.7% by weight of plant aggregates.

[0113] According to another aspect, the invention relates to a method for manufacturing 100 of a composition for construction binder according to the invention.

[0114] In some cases the construction binder will be directly incorporated into a construction material. In other applications, a construction binder composition can be prepared extemporaneously.

[0115] The manufacturing process 100 according to the invention can be implemented with devices or systems commonly used for the manufacture of construction binders or construction materials.

[0116] As illustrated in [Fig.1], the manufacturing process 100 according to the invention comprises the following steps: a grinding step 130 of a raw clay matrix in the presence of an organic additive, the organic additive comprising a deflocculating polymer having a molecular mass of at least 1000 g / mol and at least 3 negatively charged groups at a pH greater than 7. Preferably, the deflocculating polymer comprises monomers containing a sulfonate function.

[0117] In addition, the manufacturing process 100 may include the following steps: a step of acquiring 110 the characteristic values ​​of the raw clay matrix, a step of processing 120 the raw clay matrix, a step of mixing 140 with other constituents of the construction binder, and a step of adding additives 150.

[0118] The manufacturing process 100 according to the invention may include a step 110 for acquiring characteristic values ​​of the raw clay matrix. This acquisition step 110 may be implemented using an analyzer. An analyzer may be selected from: a spectrometer (infrared, NMR, Raman, X-ray fluorescence, mass spectrometer), an X-ray diffractometer, a microscope (transmission, scanning), and / or other optical sensors. In particular, this step may include measuring the LOI value and / or the contents of Al₂O₃, CaO, Fe₂O₃, K₂O, MgO, Na₂O, SiO₂, SO₃, and TiO₂ in the raw clay matrix. Specifically, it may include measuring the contents of CaO, K₂O, and / or Na₂O in the raw clay matrix or measuring the LOI value of the raw clay matrix.

[0119] The acquisition step 110 may also include the use of conventional methods for studying particle distribution. These may include the use of sieves and sedimentation (e.g., hygrometer, pipette method) and be carried out, for example, following the instructions of ASTM D422-63, ASTM D6913-04, ISO 13320:2020, NF X31-107 and possibly NF EN 933-1.

[0120] The acquisition step 110 can be followed by a step adapting the amount of deflocculant polymer used or its molecular structure. This generally allows to improve the performance of the construction binder produced by taking into account the characteristics of the raw clay matrix. This can increase the mechanical strength of the construction binder produced.

[0121] As illustrated in [Fig.1], the manufacturing process 100 according to the invention may include a treatment step 120 of the raw clay matrix.

[0122] As illustrated in [Fig. 1], the manufacturing process 100 according to the invention may include a treatment step 120 of the raw clay matrix. In particular, the treatment step 120 of the raw clay matrix may include a modification of the contents of the different particle size fractions of the raw clay matrix.

[0123] The treatment step 120 generally allows the raw material to be prepared in such a way that the construction binder has a reduced curing time and improved mechanical performance.

[0124] In particular, the raw clay matrix may advantageously have been pretreated. Preferably, the pretreatment is selected from: initial grinding, sorting, sieving and / or drying of the clay matrix. Preferably, the pretreatment is selected from: initial grinding, sorting, sieving and / or drying of the raw clay matrix. The pretreatment may, for example, include fractionation.

[0125] The treatment step 120 can generally be carried out with lump breakers, dryers, screens, and / or crushers.

[0126] Drying can, in particular, allow a reduction in the moisture content of the raw clay matrix without raising the temperature above 500°C. The dryer can, for example, be selected from a rotary dryer.

[0127] The dried raw clay matrix can advantageously undergo a screening step, for example, within a screen. This step will preferably remove aggregates with a diameter greater than or equal to 2 cm, and more preferably those with a diameter greater than or equal to 1 cm. The screen can, for example, be selected from a rotary screen.

[0128] A manufacturing process 100 according to the invention comprises a grinding step 130 of a raw clay matrix in the presence of an organic additive as described above.

[0129] Grinding can, for example, be carried out using a hammer mill, a ball mill, or a rod mill. As will be detailed, the grinding can be performed in such a way as to control the D50 of the materials used.

[0130] Preferably, during the formation of the construction binder composition, the raw clay matrix may have a D50 less than or equal to 500 pm, preferably less than or equal to 250 pm, more preferably less than or equal to 100 pm or even more preferably less than or equal to 50 pm, more preferably less than 45 pm.

[0131] The organic additive comprises a deflocculant polymer having a molecular mass of at least 1000 g / mol and at least three negatively charged groups at a pH greater than 7. Advantageously, the deflocculant polymer may comprise sulfonate functional groups. It may also comprise monomers containing a melamine ring, said deflocculant polymer having a main chain formed of a repeating sequence in which the melamine rings are linked together by covalent bonds.

[0132] In particular, this grinding step 130 can be carried out a few moments before the use of the construction binder composition and its mixing with the other constituents of the construction binder. Alternatively, the grinding step 130 can be carried out well in advance, and the construction binder composition thus formed is kept in a dry state for subsequent mixing with other components of the construction binder or aggregates. Preferably, the process according to the invention uses a binder composition formed extemporaneously. Alternatively, the process according to the invention uses a binder formed at least 6 hours, preferably at least 24 hours, before its use and, for example, at another site.

[0133] As illustrated in [Fig. 1], the manufacturing process 100 according to the invention may include a step 140 of mixing the ground raw clay matrix with other constituents of a construction binder. This may, for example, include mixing with at least one precursor and / or at least one activator.

[0134] The mixing step 140 can generally be carried out with a mixing device such as a mixer or blender, for example a powder blender.

[0135] In particular, as detailed later, the mixing step 140 may include the use of hoppers, weighing means, volumetric dosing means, transport means such as augers and / or aerodynamic systems, mixer and / or blender.

[0136] The mixing step 140 is generally carried out over a sufficient period to create an intimate mixture between the different components of the binder composition. The parameters for achieving such a result may vary depending on the components of the binder.

[0137] The mixing step 140 may include mixing the constituents of the binder composition for at least 5 seconds, preferably for at least 10 seconds, more preferably for at least 20 seconds, and even more preferably for at least 30 seconds. The mixing will generally take place over a period of 20 minutes or less, preferably for no more than 15 minutes, more preferably for no more than 10 minutes, and even more preferably for no more than 5 minutes.

[0138] In particular, the mixing step 140 can be carried out in several substeps. For example, initially, the mixing process 140 may include premixing a ground raw clay matrix and an activation composition, preferably an alkaline activation composition. Furthermore, during this premixing, the process according to the invention may advantageously include the addition of a calcined metal oxide composition. Preferably, this premix is ​​not hydrated. Alternatively, the mixing process 140 may include premixing a ground raw clay matrix and an activation composition, preferably an alkaline activation composition.

[0139] A manufacturing process 100 according to the invention includes a step of adding additives 150. The additives are, for example, those described above.

[0140] According to another aspect, the invention relates to a method for manufacturing 200 of a construction material according to the invention.

[0141] The manufacturing process 200 according to the invention can be implemented with devices or systems commonly used for the manufacture of construction binders or construction materials.

[0142] As illustrated in [Fig.2], the manufacturing process 200 of a construction material according to the invention comprises the following steps: a construction binder formation step 210 and an aggregate addition step 230.

[0143] In addition, the manufacturing process 200 of a construction material according to the invention may include a step of adding 220 water.

[0144] The construction binder formation step 210 can be carried out using the construction binder composition. Alternatively, the construction binder composition can be manufactured during the construction binder formation process.

[0145] The step of adding aggregates 230 can be carried out with the aggregates described above. EXAMPLES

[0146] The invention is described in more detail below with reference to the following experimental examples. These examples are provided for illustrative purposes only and are not intended to be limiting unless otherwise stated. Thus, the invention should in no way be interpreted as being limited to the following illustrative examples, but rather as encompassing all the variations that become evident from the teaching provided herein.

[0147] Comparative additives

[0148] For comparison purposes, comparative organic additives are used.

[0149] In particular, the following organic additives are used: - A: triisopropanolamine; - B: ribose; - C: triisopropanolamine + ribose.

[0150] Synthesis of deflocculating polymers comprising naphthalene sulfonate cores forming the main chain

[0151] Deflocculating polymers comprising naphthalene nuclei can be formed by condensation between formaldehyde and a substituted or unsubstituted naphthalene, thus making it possible to form a polymer with a main chain made up of naphthalene nuclei.

[0152] Deflocculating polymers containing naphthalene-based monomers, having a main chain with repeating sequences of covalently linked naphthalene nuclei, are synthesized by a series of three steps. The first step consists of attaching methoxyl (-CH2OH) groups to the active positions of naphthalene by reaction with formaldehyde in an alkaline medium, preferably at a pH of 8-10.

[0153] Next, sulfonation is carried out by adding sodium bisulfite in an alkaline medium, with sulfonation of only one of the methoxyl groups occurring at a pH of 10.

[0154] Finally, condensation polymerization is carried out, which can be interrupted to reach a degree of polymerization corresponding to an average molecular mass of 2,000 to 25,000 g / mol.

[0155] This step is preferably carried out at a pH of 5-6 and at a temperature of 80°C, followed by neutralization, for example by the addition of NaOH.

[0156] Synthesis of deflocculating polymers comprising melamine cores forming the main chain

[0157] Deflocculating polymers comprising melamine groups can be formed by condensation between formaldehyde and a substituted or unsubstituted melamine. This makes it possible to form a deflocculating polymer comprising a main chain formed by a chain of melamine groups or nuclei.

[0158] In particular, deflocculating polymers comprising monomers containing a melamine core, said deflocculating polymer having a main chain formed of a repeating sequence where the melamine cores are linked together by covalent bonds, can be formed by condensation between formaldehyde and melamines through three steps: - Fixation of methoxyl groups -CH2OH onto amine groups -NH2 of melamine by reaction with formaldehyde in an alkaline medium. Preferably, at pH 8-10; - Fixation of sulfonates. This is carried out by the addition of sodium bisulfite in an alkaline medium. The sulfonation of only one of the methoxyl groups... produced when one mole of sulfonate is added per mole of melamine at pH=10; - Condensation polymerization. Condensation can be stopped for a degree of polymerization n between 4 and 25, or for example an average molecular mass of 2,000 to 25,000 g.mol'. Condensation is preferably carried out at pH 5-6 and 80°C followed by neutralization, for example by the addition of NaOH, in order to generate a deflocculating polymer mixture with a slightly basic pH.

[0159] Characterization of the clay matrix

[0160] The raw clay matrix is ​​analyzed by X-ray fluorescence according to the indications of standards NF EN 196-2 and NF EN 15309

[0161] X-ray fluorescence tests on compressed beads or pellets are carried out to determine the chemical composition of a sample, that is, to quantify its major elements and possibly its trace elements. The samples analyzed have a particle size < 1 mm and are dried. The dried clay matrix is ​​then formed into a bead or pellet.

[0162] The results obtained in percentage of oxides concern the major elements: Al, Ca, Cr, Fe, K, Mg, Na, P, Pb, Si, Ti, V and W. The loss on ignition (LOI) measured during the preparation of the samples makes it possible to predict the potential presence of organic matter, carbonates and / or sulfates, which are elements that can be impactful.

[0163] Preparation of the clay matrix

[0164] The clay matrix is ​​screened and sieved to 10 mm. The moisture content of the clay is measured as described in ISO 12570:2000.

[0165] In order to illustrate the effect of the initial particle sizes and typologies of raw clay matrices on the mechanical properties of construction binders, two clay matrices (Al and A2) are used and their properties are presented in Tables 2 and 3 below. [Tables 2] Clay matrix D10 D50 D90 MOHS hardness Al 10 70 180 2 to 3 A2 5 40 130 5 to 7 [Tables 3] Matrix Arg ilous LOI A12O 3 CaO Fe2O 3 k2o MgO Na2O SiO 2 so3 TiO 2 Al 7.67 10.9 6.3 9.9 1.95 6.27 2.12 48.95 3.3 1.34 A2 12.12 9.4 10.1 7.3 1.56 4.33 1.32 47.71 4.21 0.92

[0166] Methodology for measuring the mechanical properties of construction binders

[0167] The construction binders described in Table 3 above are prepared in test specimens and their mechanical resistance is measured at different times.

[0168] Mechanical resistance of a test specimen means its resistance to compression, such compression being measured according to standard NF EN 771-3+A1 / CN and is expressed in Mega Pascal (MPa).

[0169] Withdrawal calculation

[0170] Shrinkage is calculated according to the cement test standard from NF EN 197-1, classic method for cements and carried out on standardized mortar.

[0171] Preparation of a crushed raw clay matrix

[0172] Dry grinding is carried out between a prepared raw clay matrix and a deflocculating polymer according to the invention in predetermined quantities. In some cases, several raw clay matrices are combined during the grinding step. The results presented relate to an addition before grinding, but similar results are obtained when the addition occurs during grinding.

[0173] Preparation of a construction binder and then of a material for a construction binder

[0174] The ground raw clay matrix described above is combined in a mixer with blast furnace slag and an activator (e.g., clinker) and water. The mixtures are prepared such that the construction binder comprises 40% by weight of ground raw clay matrix; 25% by weight of blast furnace slag; 35% by weight of CEM I (a mixture of 95% clinker and 5% gypsum on average).

[0175] Alternatively, the preparation of the composition is directly followed by the preparation of the binder. In this case, a dry premixing is carried out between a raw clay matrix ground according to the invention in predetermined quantities, then the slag, CEM I / Portland cement and water are added.

[0176] The mixture is blended at a low speed, approximately 60 revolutions per minute, for 30 seconds. Then, sand is added and the mixture is blended at a higher speed, approximately 120 revolutions per minute, for one minute. The water-to-dry-matter mass ratio of the construction binder is adjusted to a value between 0.4 and 0.6. In one particular example, the construction material, a mortar, comprises 25% by weight of binder and 75% by weight of sand; this mixture is then supplemented with water to achieve a water-to-dry-matter mass ratio of 0.45.

[0177] The mortar made from the construction binder thus produced is then poured into a mold and left to mature at room temperature, i.e., approximately 20 degrees Celsius, for twenty-eight days in water. Alternatively, the mortar can be poured in a mold and then left to mature for less than 24 hours in a curing stage, at room temperature, i.e., approximately 25 degrees Celsius, or preferably under heat treatment. During this curing stage, the mold can be sealed or the top layer of the building material can be coated with a curing compound to limit / prevent evaporation.

[0178] Table 4 below presents, for different formulations of construction binders including five comparative formulations (REFO, REF1, REF2, REF3, REF4) and two formulations according to the invention (EXP1, EXP2). [Tables 4] Composition Name Organic Additive Total Quantity of Organic Additive (on clay) Raw Clay Matrix Used REFO-Al Na (no deflocculant polymer) 0% Al REFO-A2 Na (no deflocculant polymer) 0% A2 REF1 - Al A - triisopropanolamine - added during grinding 3% Al REF2-A1 B - ribose - added during grinding 3% Al REF3-A1 C - triisopropanolamine + ribose - added during grinding 3% (1.5% + 1.5%) Al REF4-A1 PNS - added after grinding 3% Al REF1-A2 A - triisopropanolamine - added during grinding 3% A2 REF2-A2 B - ribose - added during grinding 3% A2 REF3-A2 C - triisopropanolamine + Ribose - added during grinding 3% (1.5% + 1.5%) A2 REF4 - A2 PNS - added after grinding 3% A2 EXP1 - Al PNS - 6000 g / mol - added during grinding 3% Al EXP1 - A2 PNS - 9000 g / mol - added during grinding 3% A2 EXP2 - Al PMS - 6000 g / mol - added during grinding 3% Al EXP2 - A2 PMS - 9000 g / mol - added during grinding 3% A2

[0179] Methodology for measuring the mechanical properties of construction binders:

[0180] Once curing is complete, the mechanical strength is measured. The mechanical strength of a construction binder is understood to be its compressive strength, such compression being measured according to standard NF EN 196-1, for a prism with sides of 40 millimeters and a length of 160 millimeters and is expressed in Mega Pascals (MPa).

[0181] Comparison of construction binders according to the invention with known construction binders

[0182] Table 5 below shows the results of the mechanical resistances at 1 day and at 28 days as well as the shrinkage at 90 days according to the formulations used during grinding. [Tables 5] ID Rclj (MPa) Rc 28j (MPa) Shrinkage 90j (mm) REF0-A1 <10 <25 < -2200 REF1 - Al <72 25 <x<45 -2200<x<-2000 REF2-A1 <72 25<x<45 -2200<x<-2000 REF3-A1 <72 25<x<45 -2200<x<-2000 REF4-A1 <72 35<x<45 -2200<x<-2000 EXP1- Al > 12 >45 > -1800 EXP2- Al >12 >45 > -1800 REF0- A2 <10 <20 < -2800 REF1- A2 <10 20 <x<35 -2800<x<-2000 REF2- A2 <10 20<x<35 -2800<x<-2000 REF3- A2 <10 20<x<35 -2800<x<-2000 REF4- A2 <10 30<x<35 -2800<x<-2000 EXP1- A2 > 12 >45 >-1300 EXP2- A2 >12 >50 > -1750

[0183] Comparing the mechanical properties of the construction material prepared from ground raw clay matrix in the absence of organic additive (REF0, REF4) and in the presence of organic additive (REF1, REF2, REF3, EXP1, EXP2), Table 5 above illustrates that the presence of the tested deflocculants in the organic additive used during grinding (EXP1 and EXP1) brings an improvement in shrinkage for both clays tested (Al and A2).

[0184] Comparison of the performance of organic additives according to clays illustrates that the addition of a deflocculant polymer according to the invention makes it possible to improve the mechanical properties of the construction material for clay 1 and for clay 2.

[0185] The improvement provided by the PMS is particularly strong on clay 2

[0186] The study of formulations according to the present invention illustrates that the grinding of a raw clay matrix in the presence of a deflocculating polymer meeting certain characteristics makes it possible to achieve shrinkage values ​​at 90 days of less than 2000 mm (for Al and A2 clays).

[0187] The invention can be the subject of numerous variations and applications other than those described above. In particular, unless otherwise indicated, the various structural and functional features of each of the embodiments described above should not be considered as combined and / or closely and / or inextricably linked to one another, but rather as mere juxtapositions. Furthermore, the structural and / or functional features of the various embodiments described above may be the subject, in whole or in part, of any different juxtaposition or any different combination.

Claims

Demands

1. Use of an organic additive during the grinding of at least one raw clay matrix, characterized in that the organic additive comprises a deflocculating polymer having a molecular mass of at least 1000 g / mol and at least 3 negatively charged groups at a pH greater than 7.

2. Use of an organic additive according to claim 1, characterized in that the deflocculating polymer has a molecular mass of at least 2000 g / mol, preferably at least 5000 g / mol, more preferably at least 9000 g / mol, even more preferably at least 14000 g / mol, for example at least 22000 g / mol,

3. Use of an organic additive according to any one of claims 1 or 2, characterized in that the deflocculating polymer has at least 5, preferably at least 7, more preferably at least 9, even more preferably at least 10 negatively charged groups at a pH greater than 7.

4. Use of an organic additive according to any one of claims 1 to 3, characterized in that the deflocculating polymer has a molecular mass to number of negatively charged groups ratio at a pH greater than 7, less than or equal to 2000.

5. Use of an organic additive according to any one of claims 1 to 4, characterized in that the deflocculating polymer has a molecular mass to number of negatively charged groups ratio at a pH greater than 7, greater than or equal to 200.

6. Use of an organic additive according to any one of claims 1 to 5, characterized in that the deflocculating polymer comprises one or more poly(oxyethylene) or poly(oxypropylene) chains, the poly(oxyethylene) or poly(oxypropylene) chains having a molecular mass of at least 200 g / mol.

7. Use of an organic additive according to any one of claims 1 to 6, characterized in that the deflocculating polymer was formed from monomers comprising a melamine sulfonate group.

8. Use of an organic additive according to any one of claims 1 to 7, characterized in that the grinding is a grinding dry, that is to say that during grinding the raw clay matrix has a water content of less than or equal to 5%.

9. Use of an organic additive according to any one of claims 1 to 8, characterized in that the organic additive further comprises alkanolamines and / or triethanolamines such as triisopropanolamine (TIPA), triethanolamine (TEA), and diethanolisopropanolamine (DEIPA).

10. Use of an organic additive according to any one of claims 1 to 9, characterized in that the grinding is carried out on one or more raw clay matrices and in that at least one raw clay matrix comprises nodules of material with a MOHS hardness greater than or equal to 5.

11. Use of an organic additive according to any one of claims 1 to 9, characterized in that the grinding is carried out on several raw clay matrices and in that at least one raw clay matrix has nodules of material with a MOHS hardness greater than or equal to 5 while at least one raw clay matrix does not have nodules of material with a MOHS hardness greater than or equal to 5.

12. Use of an organic additive according to any one of claims 1 to 11, characterized in that the organic additive is added to a first raw clay matrix and then said first raw clay matrix is ​​co-milled with another raw clay matrix.

13. Crushed raw clay matrix obtained following use according to any one of claims 1 to 12.

14. Clay matrix according to claim 13 characterized in that it has a D10 between 3 and 9 pm, a D50 between 15 and 250 pm, and a D90 between 110 and 180 pm.

15. A process (100) for manufacturing a construction binder comprising: - a step of grinding (130) a raw clay matrix in the presence of an organic additive, the organic additive comprising a deflocculating polymer having a molecular mass of at least 1000 g / mol and at least 3 negatively charged groups at a pH greater than 7; - a step of mixing (140) the ground raw clay matrix with other constituents of the construction binder,

16. for example mixing with at least one precursor and / or mixing of the crushed raw clay matrix with at least one activator. Construction binder capable of being obtained by the manufacturing process according to claim 15, said binder comprising a construction binder comprising a ground raw clay matrix having a D10 of between 3 and 9 pm, a D50 of between 15 and 250 pm, and a D90 of between 110 and 180 pm; an organic additive comprising a deflocculating polymer having a molecular mass of at least 1000 g / mol and at least 3 negatively charged groups at a pH greater than 7; as well as one or more activators and / or one or more precursors.

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