Binding composition for ore aggregates

Abstract

The present invention relates to a binding composition for producing ore agglomerates, comprising at least two distinct organic binders CP1 and P2: a polymer composition CP1 comprising a nonionic or anionic, water-soluble synthetic polymer P1 having a weight-average molecular weight between 500,000 and 3 million daltons, and a nonionic or anionic, water-soluble synthetic polymer P2 having a weight-average molecular weight of more than 2 million daltons, both of which are in the form of solid particles, and P1 is obtained by a gel polymerization process of at least one nonionic or anionic monomer in the presence of at least 1% by weight of polymer P3, comprising at least one hydrophobic monomer, or at least one hydrophobic monomer, the polymer composition CP1 comprising from 0.1% to 20% by weight of at least one polymerized hydrophobic monomer. The present invention also relates to ore agglomerates comprising between 2,000 ppm and 50,000 ppm of this binding composition.

Description

[Technical Field]

[0001] The present invention relates to the technical field of ore agglomerates. The present invention relates to a binding composition for improving the agglomeration process, in particular to obtain ore cryo-agglomerates. The binding composition comprises a mixture of at least two organic polymer binders. The present invention also relates to ore agglomerates comprising the binding composition as a product. [Background technology]

[0002] Most metals are obtained from ores found naturally underground or in mines. In the first stage of metal recovery, the desired element, or metal (e.g., iron for steel), is recovered from the ore by melting it in a blast furnace. To be directly introduced into the blast furnace, the ore must be in a regular, sizable form. Otherwise, the ore particles must be converted into larger aggregates. Agglomeration is a process based on the adhesion of ore particles to each other. In metallurgy, there are five agglomeration techniques: briquetting, nodulation, extrusion, pelleting, and sintering. These techniques are known and described in many publications, including Wolfgang Pietsch's book "Agglomeration in Industry" and, in particular, European Patent No. 0,097,486. Today, the increasing use of lower-quality ores forces manufacturers to grind the ore more finely, making the agglomeration process essential.

[0003] This agglomeration process requires the use of binders or binding compositions to ensure good physical properties, such as the mechanical strength of the agglomerates. The "binders" or "binding compositions" make it possible to optimize the adhesion between the ore particles in order to form agglomerates with sufficient mechanical properties to be able to withstand the vibrations and movements experienced during the various handling operations.

[0004] Traditionally used binders include cement (Portland), clay, especially bentonite, starch, cellulose, molasses, optionally in combination with lime, etc. The use of these binders poses the problem of the presence of large amounts of impurities harmful to the industrial process (such as sulfur impurities in the steel industry) and / or resulting in aggregates with poor physical properties. In recent years, manufacturers have developed new binding compositions to address these undesirable effects. The documents U.S. Pat. No. 5,002,607 and EP 2,548,978 describe methods for producing aggregates using binding compositions comprising at least one organic synthetic polymer and at least one inorganic binder.

[0005] US Patent No. 5,833,937 relates to a method which includes a binding step in which a solution of an anionic polymer and a solution of a cationic polymer are added sequentially to mineral granules.

[0006] Typically, agglomerates such as iron ore pellets are formed by adding a binder to crushed ore and stirring in the presence of a small amount of water to form a wet mixture, which is then agitated to form (wet) green pellets. The green pellets are then fired in an oven from an inlet temperature of 200-400°C to a final temperature of near 1400°C. Such methods for forming iron ore pellets are disclosed, for example, in EP 0,225,171.

[0007] The calcination step is essential to ensure that the final agglomerates have good physical properties. However, this process is very energy intensive in terms of fossil materials. This has a major impact on the agglomeration plant, both ecologically and economically.

[0008] Considering the current energy situation, it is above all necessary to find sustainable and effective solutions that allow obtaining high-quality aggregates, i.e., respecting the physical properties expected from the technology, while simultaneously achieving productivity and energy savings.

[0009] One solution that manufacturers have found to limit the impact of producing such agglomerates is to agglomerate the ore at low temperatures, i.e., at firing temperatures not exceeding 250°C. Unfortunately, this type of method does not result in the expected physical properties of the agglomerates based on the binding composition described above. The agglomerates break before reaching the production facility, such as a blast furnace. They are difficult to handle and store. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] European Patent No. 0,097,486 [Patent Document 2] U.S. Patent No. 5,002,607 [Patent Document 3] European Patent No. 2,548,978 [Patent Document 4] U.S. Patent No. 5,833,937 [Patent Document 5] European Patent No. 0,225,171 [Non-patent literature]

[0011] [Non-Patent Document 1] "Agglomeration in Industry" by Wolfgang Pietsch Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention overcomes the shortcomings of the prior art by disclosing a binding composition that improves the agglomeration process so that ore agglomerates with satisfactory physical properties can be produced at low temperatures. [Means for solving the problem]

[0013] The present invention generally relates to a binding composition for producing ore aggregates at low temperatures, which comprises at least two distinct organic binders (a polymer composition CP1 and a polymer P2 having the function of distinct organic binders): a polymer composition CP1 comprising a nonionic or anionic water-soluble synthetic polymer P1 having a weight-average molecular weight between 500,000 and 3 million daltons, - nonionic or anionic water-soluble synthetic polymer P2 having a weight average molecular weight of more than 2 million daltons Including, The polymer composition CP1 and the polymer P2 are both present in the form of solid particles, P1 is - at least 1% by weight of a polymer P3 comprising at least one hydrophobic monomer, or at least one hydrophobic monomer, obtained by a gel polymerization process of at least one nonionic or anionic monomer in the presence of The polymer composition CP1 comprises 0.1% to 20% by weight of at least one polymerized hydrophobic monomer; Related to bonding compositions.

[0014] Another aspect of the invention relates to an ore agglomerate comprising between 2,000 ppm and 50,000 ppm of said binding composition relative to the mass of the ore agglomerate. DETAILED DESCRIPTION OF THE INVENTION

[0015] Definitions and Overview In this application, the term "polymer" refers to both homopolymers and copolymers of at least two distinct monomers.

[0016] As used herein, the term "water-soluble polymer" means a polymer that, when dissolved with stirring at 25°C for 4 hours, gives an aqueous solution in 1 L of deionized water at a concentration of 20 g / L that is free of insoluble particles.

[0017] "Anionic polymer" refers to a polymer containing at least one anionic monomer and, optionally, at least one nonionic monomer. "Nonionic polymer" refers to a polymer containing only one or more nonionic monomers. Generally, a polymer containing a monomer refers to a polymer obtained by polymerizing many molecules of that monomer.

[0018] As used herein, the term "hydrophilic monomer" means a monomer that has an octanol / water partition coefficient, Kow, of less than 1, determined at a temperature of 25°C and between pH 6 and 8.

[0019] The term "hydrophobic monomer" refers to a monomer that has an octanol / water partition coefficient, Kow, greater than 1, determined at a temperature of 25°C and between pH 6 and 8.

[0020] The octanol / water partition coefficient, Kow, is defined as follows:

[0021]

number

[0022] where [monomer]octanol = equilibrium monomer concentration in n-octanol (g / L), [monomer]water = equilibrium monomer concentration in water (g / L).

[0023] According to the present invention, the term "low temperature" means a temperature not exceeding 250°C.

[0024] In this application, the term "agglomerate" relates to a product obtained from an agglomeration technique selected from among pelletizing, sintering, nodulating, briquetting or extrusion.

[0025] "Solid particles" according to the present invention are always defined by their size. The median diameter (D 50) is defined as the largest particle dimension (diameter for spherical particles) below which half of the particle population is. Particle size refers to the average diameter measured using a laser diffraction particle analyzer according to conventional techniques known to those skilled in the art. An example of an instrument for measuring average particle size is the Mastersizer from Malvern Instruments.

[0026] According to the present invention, a range of values ​​is inclusive of the lower and upper limits, so the value ranges "between 0.1 and 1.0" and "from 0.1 to 1.0" include the values ​​0.1 and 1.0.

[0027] According to the present invention, the weight average molecular weight of a polymer is determined by measuring its intrinsic viscosity. Intrinsic viscosity can be measured by any method known to those skilled in the art. In particular, it is calculated by measuring the viscosity in solution, which involves plotting the reduced viscosity value (vertical axis) as a function of concentration (horizontal axis) and extrapolating the curve to zero concentration to determine the reduced viscosity values ​​at different concentrations. The intrinsic viscosity value is read on the vertical axis or by the least squares method. The weight average molecular weight is then calculated using the Mark-Houwink equation. [η]=KM α where [η] represents the intrinsic viscosity of the polymer determined by solution viscosimetry, K represents an empirical constant, M represents the molecular weight of the polymer, α represents the Mark-Howink coefficient. α and K depend on the particular polymer-solvent system. Tables known to those skilled in the art provide values ​​of α and K for different polymer-solvent systems.

[0028] Polymer composition CP1 and polymer P1 The binding composition of the present invention has a mass average molecular weight of 500,000 Daltons to 3 million (=3×10 6) Daltons, more preferably between 500,000 and 2,500,000 Daltons, and even more preferably between 500,000 and 2,000,000 Daltons.

[0029] Advantageously, the anionic monomer of the water-soluble polymer P1 is preferably selected from the group consisting of monomers with a vinyl functionality, in particular acrylic, maleic, fumaric, malonic, itaconic, or allylic acid. It may also contain at least one carboxylate, phosphonate, phosphate, sulfonate, or other anionically charged group. Preferred monomers from this class are, for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, acrylamidoundecanoic acid, 3-acrylamido-3-methylbutanoic acid, maleic anhydride, 2-acrylamido-2-methylpropanesulfonic acid (ATBS), vinylsulfonic acid, vinylphosphonic acid, 2-sulfoethyl methacrylate, sulfopropyl methacrylate, sulfopropyl acrylate, allylphosphonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanedisulfonic acid, their salts, and mixtures thereof. Acrylic acid or itaconic acid is preferred. Even more preferred is acrylic acid.

[0030] Thus, in certain embodiments of the present invention, the anionic monomer may be salified.

[0031] By "salified" it is meant that at least one acid functional group of the anionic monomer has been replaced with a salt that neutralizes the negative charge of the acid functional group. In other words, the unsalified form corresponds to the acid form of the monomer, e.g., RC(=O)-OH in the case of a carboxylic acid functional group, and the neutralized form of the monomer corresponds to RC(=O)-O - X + Corresponding to the type, X +corresponds to a salt having a positive charge. The neutralization of the acid functions of the water-soluble polymer may be partial or total. The salified forms advantageously correspond to salts of alkali metals (Li, Na, K, etc.), alkaline earth metals (Ca, Mg, etc.) or ammonium (e.g., ammonium ion or tertiary ammonium). Preferred salts are sodium salts. Salification may occur before or after polymerization.

[0032] As mentioned above, this does not exclude the presence in polymer P1 of at least one anionic monomer unit (not neutralized) containing a carboxylic acid function, in other words, the simultaneous presence of an anionic monomer bearing a carboxylic acid function and the same monomer bearing a carboxylate function is also possible.

[0033] Even more preferably, the polymer P1 comprises at least one anionic monomer containing a carboxylate function that is the salt of acrylic acid.Advantageously, the polymer P1 comprises at least sodium acrylate as a monomer unit.

[0034] In a preferred embodiment of the present invention, the water-soluble polymer P1 does not contain any monomer units having a sulfonic acid functional group or a salt thereof, such as acrylamido tert-butyl sulfonic acid (ATBS), allyl sulfonic acid or methallyl sulfonic acid.

[0035] Advantageously, the water-soluble polymer P1 comprises less than 50 mol % of anionic monomers, preferably between 10 mol % and 40 mol %, more preferably between 15 mol % and 30 mol % of anionic monomers.

[0036] Advantageously, the nonionic monomer can be selected, in particular, from the group consisting of water-soluble vinyl monomers. The nonionic monomer can be selected, for example, from the group comprising acrylamide, methacrylamide, N-vinylformamide (NVF), N-vinylacetamide, N-vinylpyridine, N-vinylpyrrolidone (NVP), N-vinylimidazole, N-vinylsuccinimide, acryloylmorpholine (ACMO), acryloyl chloride, glycidyl methacrylate, glyceryl methacrylate, diacetone acrylamide, hydroxyalkyl(meth)acrylates (wherein the alkyl group is advantageously C1-C3), aminoalkyl(meth)acrylates (wherein the alkyl group is advantageously C1-C3), aminoalkyl(meth)acrylamides (wherein the alkyl group is advantageously C1-C3), thioalkyl(meth)acrylates (wherein the alkyl group is advantageously C1-C3), and mixtures thereof. Preferably, at least one nonionic monomer of the polymer P1 is acrylamide.

[0037] The polymer P1 advantageously comprises at least 50 mol %, preferably between 60 mol % and 90 mol %, and even more preferably between 70 mol % and 85 mol % of at least one nonionic monomer.

[0038] The sum of the monomers is equal to 100% of the polymer P1.

[0039] According to a preferred embodiment, the polymer P1 is non-ionic.

[0040] Preferably, polymer P1 is a copolymer of acrylamide and sodium acrylate, preferably comprising between 10 mol% and 40 mol%, even more preferably between 15 mol% and 30 mol% of sodium acrylate, the sum of the two monomers preferably being equal to 100% of polymer P1.

[0041] In one embodiment of the present invention, polymer P1 comprises hydrophobic monomers.

[0042] The hydrophobic monomers of the polymer P1 have a Kow partition coefficient greater than 1 and are preferably chosen from the following list of compounds: - (meth)acrylic acid esters with alkyl and / or arylalkyl and / or ethoxyl and / or propoxyl chains; (meth)acrylamide derivatives with alkyl and / or arylalkyl and / or dialkyl and / or ethoxyl and / or propoxyl chains; anionic hydrophobic derivatives of (meth)acryloyl; and anionic monomeric derivatives of (meth)acrylamide with hydrophobic chains; n-hexyl (meth)acrylate, n-octyl (meth)acrylate, octyl (meth)acrylamide, n-tert-butyl (meth)acrylamide, lauryl (meth)acrylate, lauryl (meth)acrylamide, myristyl (meth)acrylate, myristyl (meth)acrylamide, pentadecyl (meth)acrylate, pentadecyl (meth)acrylamide, cetyl (meth)acrylate, cetyl (meth)acrylamide, oleyl (meth)acrylate, oleyl (meth)acrylamide, erucyl (meth)acrylamide, erucyl (meth)acrylamide, and combinations thereof; - a hydrophobic monomer corresponding to the general formula: CH2=CR 1 -COO-(EO) n -(PO) m -R 2 where R 1 is hydrogen or methyl; n is a number at least equal to 2, preferably a number between 6 and 100, even more preferably a number between 10 and 40; m is a number between 0 and 50, preferably a number between 0 and 20; EO is an ethylene oxide group (—CH—CH—O—), PO is a propylene oxide group (—CH—CH(CH)—O—), and R 2 is C8~C 30 Alkyl group or C8-C 30 Arylalkyl groups, where n+m is preferably from 6 to 100 or from 10 to 40. These are preferably linear alkyl groups.

[0043] Among the hydrophobic monomers P1 having alkyl chains, in particular esters of (meth)acrylic acid and derivatives of (meth)acrylamide, the alkyl groups are advantageously C1 to C5, more advantageously C1 to C3. They are preferably linear alkyls. Thus, the dialkyl groups advantageously contain two alkyl groups of C1 to C5. The arylalkyl groups of these monomers are advantageously C8 to C 30 is.

[0044] More preferably, the hydrophobic monomers of P1 are selected from the following list of compounds: C8 to C 16 Halogen alkyl (preferably bromoalkylated) derivatives of methacrylamide dimethylaminopropyl containing alkyl chains, ethoxylated behenyl methacrylate, diethyl acrylamide, n-tert-butyl acrylamide and mixtures thereof.

[0045] Advantageously, according to a preferred embodiment, the polymer P1 is a C8-C 16 The composition comprises at least one hydrophobic monomer selected from haloalkyl derivatives of methacrylamide dimethylaminopropyl containing alkyl chains, ethoxylated behenyl methacrylate, diethyl acrylamide, n-tert-butyl acrylamide, and mixtures thereof.

[0046] Polymer P1 may be linear or structured. "Structured polymer" refers to a non-linear polymer with side chains that form a highly entangled state, resulting in a very high, low-gradient viscosity when the polymer is dissolved in water. This structuring results from the presence of at least one polyethylenically unsaturated monomer (i.e., having at least two unsaturated carbon-carbon functional groups), such as vinyl, allyl, acrylic, and epoxy functional groups. Examples include sodium allyl sulfonate, sodium methallyl sulfonate, sodium methallyl disulfonate, methylenebisacrylamide, diallylamine, triallylamine, triallylammonium chloride, and tetraallylammonium chloride. Structuring can also be achieved by the addition of at least one macroinitiator, such as polyperoxide or polyazo, or at least one transfer polyagent, such as polymercaptan.

[0047] The polymer P1 can also be structured using controlled radical polymerization (CRP) techniques, in particular those of the reversible addition-fragmentation chain transfer (RAFT) type.

[0048] The polymer P1 can be structured in a comb, star, or other structure known to those skilled in the art. The structured polymer P1 remains water-soluble.

[0049] Advantageously, the polymer P1 is structured in a star shape, ie it has a central part (called the core) and polymer-based arms radiating from said central part.

[0050] According to the present invention, the polymer composition CP1 is in the form of solid particles, and the median diameter by number of the solid particles (D 50 ) is generally greater than 500 micrometers (μm).

[0051] Preferably, the polymer P1 is at least 1% by weight of a polymer P3 of at least one hydrophobic monomer, or at least one hydrophobic monomer, obtained by a gel polymerization process of at least one nonionic or anionic monomer in the presence of Polymer composition CP1 comprises from 0.1% to 20% by weight of at least one polymerized hydrophobic monomer.

[0052] In one embodiment of the present invention, the polymer P1 is obtained by gel polymerization of at least one nonionic or anionic monomer in the presence of at least 1% by weight of a polymer P3 of at least one hydrophobic monomer, The polymer composition CP1 comprises 0.1% to 20% by weight of at least one hydrophobic monomer polymerized within the polymer P3. In this embodiment, the polymer composition CP1 consists of the polymer P1 and the polymer P3.

[0053] In another embodiment of the invention, the polymer P1 is obtained by a gel polymerization process of at least one nonionic or anionic monomer in the presence of at least one hydrophobic monomer, The polymer composition CP1 comprises 0.1% to 20% by weight of at least one hydrophobic monomer polymerized within the polymer P1. In this embodiment, the polymer P1 comprises at least a hydrophobic monomer. In this embodiment, the polymer composition CP1 consists of the polymer P1.

[0054] According to the present invention, "A and / or B" means either A, B, or A and B.

[0055] The gel polymerization of the method of the present invention is carried out free radically, which includes free radical polymerization using UV, azo, redox or thermal initiators, as well as controlled radical polymerization (CRP) techniques, particularly RAFT-type techniques.

[0056] At least one transfer agent can be used. This can be selected from sulfur compounds such as thioglycolic acid, mercapto alcohols, or dodecyl mercaptan; amines such as ethanolamine, diethanolamine, or morpholine; and phosphites such as sodium hypophosphite. In the case of RAFT-type polymerization, one or more specific polymerization regulators can be used, such as those containing a transfer group containing an -S-CS- functional group. Mention can be made in particular of compounds from the xanthate (-S-CS-O-), dithioester (-S-CS-carbon), trithiocarbonate (-S-CS-S-), or dithiocarbamate (-S-CS-nitrogen) families. Among compounds from the xanthate family, O-ethyl-S-(1-methoxycarbonylethyl)xanthate can be advantageously used due to its compatibility with acrylic monomers.

[0057] The polymerization initiator used to obtain the polymer P1 may be any compound that dissociates into radicals under the polymerization conditions, such as, for example, organic peroxides, hydroperoxides, hydrogen peroxide, persulfates, azo compounds, and redox catalysts. The use of water-soluble initiators is preferred. In some cases, it may be advantageous to use a mixture of different polymerization initiators, for example, a mixture of azo compounds with redox catalysts.

[0058] The polymerization initiators are used in conventional amounts, which may vary, for example, from 0.0001 to 2% by weight, preferably from 0.001 to 1% by weight, relative to the monomers to be polymerized.

[0059] As the oxidizing component, the redox catalyst advantageously comprises at least one of the aforementioned compounds. As the reducing component, the redox catalyst is advantageously selected from ascorbic acid, glucose, sorbose, bisulfites, sulfites, thiosulfates, hyposulfites, pyrosulfites, alkali metal, iron(II) ion or silver ion forms, or metal salts such as sodium hydroxymethylsulfoxylate. Mohr's salt (NH4)2Fe(SO4)2,6H2O is preferably used as the reducing component of the redox catalyst.

[0060] As an example, based on the amount of monomer used in the polymerization, 1 mol% of the reducing component of the redox catalyst system is 5 × 10 -6 , 5 × 10 at 2 mol% of the oxidation component of the redox catalyst -5 In place of the oxidant component of the redox catalyst, one or more water-soluble azo initiators can also be used.

[0061] The polymerization of the water-soluble polymer P1 is carried out in the absence of oxygen by introducing, in the appropriate order, initiators known to those skilled in the art into the solution to be polymerized, either in a form soluble in an aqueous medium or in the form of a solution in an organic solvent.

[0062] All components are preferably soluble, more preferably soluble in water.

[0063] As soon as the polymerization begins, the reaction mixture is heated or increases in temperature (exothermic reaction) depending on the selected initiation conditions. Advantageously, the heat of polymerization released increases the temperature of the reaction mixture from 80° C. to 150° C., preferably from 80° C. to 100° C. The polymerization is advantageously carried out at atmospheric pressure. Those skilled in the art know how to select the appropriate equipment for an optimal polymerization.

[0064] At the end of the polymerization reaction, the polymer gel P1 is subjected to aging, usually for at least 60 minutes.

[0065] "Aging" means leaving the gel in the polymerization reactor at the final polymerization temperature.

[0066] The product obtained from the polymerization is generally a viscous polymer gel P1, which is then granulated. Granulation consists of cutting the gel into small pieces. Advantageously, according to the present invention, the average size of these gel pieces is less than 1 cm, more advantageously between 4 and 8 mm. Those skilled in the art know how to select the appropriate means for optimal granulation. The next step is to grind these gel pieces. The grinding step consists of breaking down large polymer particles into smaller ones. This can be done by shearing or by mechanically crushing the particles between two hard surfaces. Various types of equipment known to those skilled in the art can be used for this purpose, such as rotor mills, which use rotating parts to crush the particles on a compression blade, or roller mills, which crush the particles between two rotating rollers. Sieving, which follows grinding, aims to remove medium-sized particles, or too small or too large particles, depending on the specifications. The next step is drying the polymer P1. The drying means and its conditions (time + temperature) are routinely selected by those skilled in the art. Industrially, drying is advantageously carried out by means of a fluidized bed or rotor dryer using air heated to a temperature advantageously between 70°C and 200°C, the temperature of the air depending on the nature of the product and the drying time applied. The product obtained is polymer composition CP1. Polymer composition CP1 is then in powder form.

[0067] Polymer P3 According to one aspect of the present invention, the polymer P1 is preferably obtained by a gel polymerization method known to those skilled in the art in the presence of at least 1% by weight of the polymer P3 of at least one hydrophobic monomer. In addition to the hydrophobic monomer, the polymer P3 may also contain at least one hydrophilic monomer. In this case, the polymer composition CP1 consists of the polymer P1 and the polymer P3.

[0068] The hydrophilic monomers of polymer P3 have a Kow partition coefficient of less than 1 and are preferably selected from the group comprising acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N,N-dialkylacrylamide, N,N-dialkylmethacrylamide, alkoxylated esters of acrylic acid, alkoxylated esters of methacrylic acid, N-vinylpyridine, N-vinylpyrrolidone, hydroxyalkyl acrylates, hydroxyalkyl methacrylates, and mixtures thereof; monomers having a carboxylic acid functional group, including acrylic acid, methacrylic acid, itaconic acid, and maleic acid, and salts thereof; monomers having a sulfonic acid functional group, including acrylamido tert-butyl sulfonic acid (ATBS), allyl sulfonic acid, methallyl sulfonic acid, and salts thereof; monomers having a phosphonic acid functional group, and salts thereof; and mixtures thereof. Generally, the monomer salt is a salt of at least one alkali metal (preferably sodium), at least one alkaline earth metal (preferably calcium or magnesium), or at least one ammonium (preferably quaternary ammonium) salt.

[0069] The hydrophobic monomers of polymer P3 have a Kow partition coefficient greater than 1 and are preferably selected from the following list of compounds: - (meth)acrylic acid esters with alkyl and / or arylalkyl and / or ethoxyl and / or propoxyl chains; (meth)acrylamide derivatives with alkyl and / or arylalkyl and / or dialkyl and / or ethoxyl and / or propoxyl chains; anionic hydrophobic derivatives of (meth)acryloyl; and anionic monomeric derivatives of (meth)acrylamide with hydrophobic chains; n-hexyl (meth)acrylate, n-octyl (meth)acrylate, octyl (meth)acrylamide, n-tert-butyl (meth)acrylamide, lauryl (meth)acrylate, lauryl (meth)acrylamide, myristyl (meth)acrylate, myristyl (meth)acrylamide, pentadecyl (meth)acrylate, pentadecyl (meth)acrylamide, cetyl (meth)acrylate, cetyl (meth)acrylamide, oleyl (meth)acrylate, oleyl (meth)acrylamide, erucyl (meth)acrylamide, erucyl (meth)acrylamide, and combinations thereof; - a hydrophobic monomer corresponding to the general formula: CH2=CR 1 -COO-(EO) n -(PO) m -R 2 where R1 is hydrogen or methyl; n is a number at least equal to 2, preferably between 6 and 100, even more preferably between 10 and 40; m is a number between 0 and 50, preferably between 0 and 20, EO is an ethylene oxide group (-CH2-CH2-O-), PO is a propylene oxide group (-CH2-CH(CH3)-O-), and R 2 is C8~C 30 Alkyl group or C8-C 30 Arylalkyl groups, where n+m is preferably from 6 to 100 or from 10 to 40. These are preferably linear alkyl groups.

[0070] Among the hydrophobic monomers P3 having alkyl chains, in particular esters of (meth)acrylic acid and derivatives of (meth)acrylamide, the alkyl groups are advantageously C1 to C5, more advantageously C1 to C3. They are preferably linear alkyls. Thus, the dialkyl groups advantageously contain two alkyl groups of C1 to C5. The arylalkyl groups of these monomers are advantageously C8 to C6. 30 is.

[0071] More preferably, the hydrophobic monomer of P3 is selected from the following list of compounds: C8 to C 16 Halogen alkyl (preferably bromoalkylated) derivatives of methacrylamide dimethylaminopropyl containing alkyl chains, ethoxylated behenyl methacrylate, diethyl acrylamide, n-tert-butyl acrylamide and mixtures thereof.

[0072] Polymer P3 comprises between 10% and 100% by weight, even more preferably between 10% and 90% by weight, of at least one hydrophobic monomer.

[0073] Advantageously, polymer P3 is a terpolymer of diethylacrylamide, n-tert-butylacrylamide and sodium 2-acrylamido-2-methylpropanesulfonate.

[0074] In a preferred embodiment, the polymer P3 is functionalized at the end of the polymer chain with at least one group selected from hydroxyl, cyano, amine, phosphate, phosphonate, sulfate, sulfonate, xanthate, trithiocarbonate, dithiocarbamate and dithioester. The polymer P3 may also be chain-unfunctionalized.

[0075] Preferably, polymer P3 does not contain any carbon-carbon double bonds.

[0076] According to this aspect of the invention, the polymer P1 is obtained according to the following conditions: - An aqueous solution of polymer P1 is prepared by adding between 1% and 25% by weight, preferably between 2% and 20% by weight, and more preferably between 3% and 15% by weight of polymer P3, where % is expressed by weight relative to the total weight of the aqueous solution, and comprising a monomer selected from the list above; a quantity of water; and optionally additives, the total weight concentration of the monomers being between 10% and 60% by weight, preferably between 20% and 55% by weight, and more preferably between 25% and 50% by weight, relative to the total weight of the aqueous solution. The polymerization compounds are dissolved, for example, with stirring, in the aqueous polymerization medium. This solution, also called the polymerization charge, is adjusted to a starting temperature between -20°C and 50°C. Advantageously, this starting temperature is adjusted between -5°C and 30°C, more advantageously between 0°C and 20°C. Those skilled in the art know how to determine the pH to be reached, as well as the amount and choice of pH adjusters, depending on the nature of the monomers (nonionic, anionic, etc.) and the chemical nature of the polymer to be synthesized. - Degassing after dissolution to remove traces of residual oxygen with at least one inert gas, which is usually passed through the solution. Suitable inert gases for this purpose are, for example, nitrogen, carbon dioxide, or noble gases such as neon or helium. Argon can also be used.

[0077] The hydrophilic monomers present in polymer P3 can facilitate the solubilization of polymer P3 in water, even when polymer P3 is primarily composed of hydrophobic monomers. In this case, the hydrophilic monomers act as cosolvents for polymer P3. Therefore, the polymerization solution contains no insoluble components. While polymer P1 is generally water-soluble, polymer P3 is not necessarily water-soluble.

[0078] According to a second aspect of the invention, the polymer P1 is obtained by a gel polymerization method in the presence of at least one hydrophobic monomer. In this particular case, the polymer P1 comprises, in addition to the anionic and / or nonionic water-soluble monomers mentioned above, at least one hydrophobic monomer.

[0079] The hydrophobic monomers are generally selected from the same list of hydrophobic monomers cited above for polymer P3. To do this, preferably 1% to 20% of at least one hydrophobic monomer is introduced into the polymerization charge of P1. However, preferably, polymers P3 and P1 do not contain cationic or zwitterionic monomers.

[0080] According to this aspect of the invention, optionally, the or these hydrophobic monomers are contacted with one or more surfactants.

[0081] A "surfactant" is an agent that can emulsify oil in water. Generally, surfactants are considered to be compounds with an HLB of 10 or higher.

[0082] The hydrophilic-lipophilic balance (HLB) of a chemical compound is a measure of how hydrophilic or lipophilic the compound is, and is determined by calculating the values ​​of various regions of the molecule, as described by Griffin in 1949. Griffin assigned dimensionless numbers between 0 and 20 to provide information about the solubility in water and oil. A substance with an HLB value of 10 distributes between the two phases so that its hydrophilic groups (molecular weight Mh) protrude completely into the water and its hydrophobic groups (molecular weight Mp) adsorb to the non-aqueous phase. The HLB value of a substance with a total molecular weight M and a hydrophilic portion of molecular weight Mh is given by the following formula: HLB=20(Mh / Mp)

[0083] The surfactant may be any suitable surfactant selected from anionic surfactants, cationic surfactants, nonionic surfactants, and combinations thereof. In some embodiments, the surfactant may exist as a dimer. For example, the surfactant may include one polar head group and two nonpolar tail groups, or two polar head groups and one nonpolar tail group, or two polar head groups and two nonpolar tail groups. The surfactant or mixture of surfactants can be chosen from the following list of compounds: ethoxylated sorbitan esters such as ethoxylated sorbitan oleate with 20 moles of ethylene oxide (EO210), sorbitan laurate with 20 moles of ethylene oxide or ethoxylated sorbitan monostearate with 20 moles of ethylene oxide; decaethoxylated oleodecyl alcohol; heptaethoxylated lauryl alcohol; castor oil ethoxylated with 40 moles of ethylene oxide; polyethoxylated alkylphenols; polyethoxylated cetyl ethers; derivatives of quaternary amines; sodium lauryl sulfate; condensation products of fatty alcohols with ethylene oxide; condensation products of alkylphenols with ethylene oxide; amino fatty acid condensation products with 5 or more ethylene oxide units; tristerylphenol ethylene oxide; alkyl polyglucosides; amine oxides, glucamides; salts of alkylbenzenesulfonic acid, water-soluble surface-active polymers. Preferably, less than 10% by weight of surfactant is added to the polymerization charge.

[0084] Polymer P2 The binder composition according to the invention comprises a polymer composition CP1 containing a polymer P1 as well as a polymer having a weight average molecular weight of 2 million (2×10 6 The water-soluble polymer P2 preferably has a weight-average molecular weight of more than 5 million daltons. The water-soluble polymer P2 generally has a weight-average molecular weight of less than 40 million daltons. The polymer P2 comprises at least one nonionic or anionic monomer.

[0085] Preferably, polymer P2 has a weight average molecular weight greater than the weight average molecular weight of polymer P1.

[0086] The nonionic and anionic monomers are preferably chosen from the same compounds as those mentioned above for P1. Advantageously, the anionic monomers may be salified as previously described.

[0087] Preferably, the water-soluble polymer P2 comprises between 5 mol % and 100 mol %, more preferably between 10 mol % and 70 mol %, even more preferably between 20 mol % and 50 mol % of at least one anionic monomer.

[0088] Advantageously, the water-soluble polymer P2 does not contain monomer units having sulfonic acid functional groups or salts thereof, such as acrylamido tert-butylsulfonic acid (ATBS), allylsulfonic acid and methallylsulfonic acid.

[0089] The polymer P2 is linear or structured. The polymer P2 may be structured as described above for P1. The structured polymer P2 remains water-soluble.

[0090] The polymer P2 is present in the form of solid particles, for example in the form of a powder or microbeads. The powder of the polymer P2 can be obtained by gel polymerization, precipitation polymerization or polymerization in aqueous solution followed by drum drying, spray drying or radiation drying, such as microdrying by wave or drying in a fluidized bed. The powder form can also be obtained by water-in-oil emulsion polymerization (inverse emulsion polymerization) followed by a distillation / concentration step and spray drying of the resulting liquid.

[0091] The P2 polymer microbeads are advantageously obtained by inverse suspension polymerization.

[0092] Preferably, the polymer P2 is in the form of a powder resulting from gel polymerization or microbeads resulting from inverse suspension polymerization.

[0093] According to the invention, the polymer P2 is in the form of solid particles, the median diameter by number of the solid particles (D 50 ) is greater than 500 micrometers (μm).

[0094] Particularly preferably, the polymer P2 is a copolymer containing between 5 mol % and 100 mol % sodium acrylate.

[0095] Bonding compositions according to the present invention For the purpose of ore agglomeration at low temperatures, the binding composition according to the invention comprises at least two polymers with distinct organic binder functional groups: polymer compositions CP1 and P2.

[0096] According to a preferred embodiment of the invention, the bonding composition comprises at least 50% by weight of the polymer composition CP1.

[0097] According to a preferred embodiment of the present invention, the bonding composition comprises only two separate organic binders, polymer compositions CP1 and P2. According to this preferred embodiment, the bonding composition preferably comprises between 75% and 90% by weight of polymer composition CP1 and between 10% and 25% by weight of polymer P2. The total weight of CP1 + P2 is equal to 100%.

[0098] According to another embodiment of the invention, the bonding composition may also comprise at least one other component of a different nature, which makes it possible to improve the physical properties of the aggregate and further increase the bonding strength of said composition.

[0099] One of these components may be an organic binder other than CP1 and P2, such as an epoxy resin, a polyphenol resin, or a formaldehyde resin. Rolkem™ brand resins are preferred.

[0100] Thus, according to another aspect of the invention, the bonding composition comprises less than 40% by weight of polymer composition CP1, between 1% and 25% by weight of polymer P2, and at least 50% by weight of another organic bonding agent other than CP1 and P2, the total weight of the components being equal to 100%.

[0101] The binding composition may also comprise an inorganic binder, hereinafter designated LI, advantageously in the form of solid particles. The inorganic binder LI may be selected from sodium carbonate, sodium bicarbonate, sodium phosphate, sodium silicate, urea, calcium oxide, bentonite and mixtures thereof. A preferred inorganic binder LI is sodium silicate. According to the invention, the binder LI may be present in the form of solid particles, the median diameter (D 50 ) is between 500 micrometers and 5000 micrometers, more preferably between 500 micrometers and 2000 micrometers.

[0102] Thus, according to an alternative embodiment of the invention, the bonding composition comprises at least 50% by weight of an inorganic binder LI, between 10% and 49% by weight of a polymer composition CP1, and between 0.5% and 5% by weight of a polymer P2, the total weight of CP1+P2+LI being equal to 100%.

[0103] Another embodiment of the invention relates to a bonding composition comprising between 10% and 40% by weight of an inorganic binder LI, between 5% and 20% by weight of a polymer composition CP1, at least 50% by weight of an organic binder other than P1 and P2, and less than 5% by weight of a polymer P2, the total weight of the components being equal to 100%.

[0104] The bonding composition according to the present invention is formed by mixing its components, each of which is in powder form.

[0105] The bonding composition particularly preferably contains less than 0.1% by weight of elemental sulfur.

[0106] aggregate A final aspect of the invention relates to ore agglomerates advantageously containing between 2,000 ppm and 50,000 ppm of binding composition relative to the mass of said ore agglomerates.

[0107] Agglomerates are generally formed by adding the binding composition to the crushed ore under agitation in the presence of a small amount of water to form a wet mixture. This mixture is then agglomerated using a preferred agglomeration technique (pelletizing, sintering, nodulating, extrusion, or briquetting). The resulting agglomerates are then calcined in an oven at a temperature not exceeding 250°C.

[0108] The agglomerates may be subjected to further subsequent physical and / or chemical treatments depending on the desired application, as known to those skilled in the art. [Example]

[0109] The following examples serve to best illustrate the advantages of the present invention in a clear and non-limiting manner.

[0110] I. Synthesis of polymer P1 and polymer composition CP1:

[0111] (Example 1) (P1a: Counterexample): Synthesis of low molecular weight acrylamide homopolymer P1a via aqueous liquid route Polymer P1a is synthesized by aqueous liquid radical polymerization from an aqueous charge containing 40.0% by weight of acrylamide monomer according to the following protocol: 133 g of water and 6 g of sodium hypophosphite are introduced sequentially into a 1 L jacketed reactor. The pH of the aqueous phase is adjusted to a pH value between 2.0 and 3.0 using a dilute solution of sulfuric acid. The charge is then heated to a temperature between 79 and 81 °C using a jacketed reactor. Once the aqueous charge has reached temperature, 800 g of a 50% by weight aqueous solution of acrylamide is poured in over 120 minutes. In parallel, a 6.5% by weight aqueous solution of sodium persulfate is poured in over 130 minutes. Once the sodium persulfate injection is complete, the whole is allowed to react at the same temperature for 1 hour to reduce the level of residual monomer. Polymer P1a is obtained in the form of a viscous liquid containing 40% by weight of polymer. The molecular weight of polymer P1a is 100,000 daltons.

[0112] (Example 2) (CP1b and P1b: present invention): A polymer composition CP1b containing an acrylamide / sodium acrylate copolymer P1b is synthesized by the gel route by adding polymer P3 containing 83% by weight of hydrophobic monomers to the 2% by weight polymerization charge.

[0113] In the first step, polymer P3 having a composition of 5% by weight of n-tert-butylacrylamide, 78% by weight of diethylacrylamide, and 17% by weight of sodium 2-acrylamido-2-methylpropanesulfonate is synthesized by radical polymerization in an aqueous solution.

[0114] In the second step, polymer P1b is synthesized by radical polymerization via gel route from an aqueous charge containing 2% by weight of polymer P3 according to the following protocol: 20 g of polymer P3 composition (361 g of a 5.5% by weight aqueous solution of polymer P3), 79 g of acrylic acid, 403 g of acrylamide at 50% by weight in water, and 70 g of sodium chloride are introduced into a 1.5 L beaker. The charge is neutralized with 87 g of sodium hydroxide at 50% by weight in water to a pH between 6.5 and 7.5. The charge is then cooled to 0°C and placed in a Dewar flask. 1.5 g of azobisisobutyronitrile are then introduced into the charge, which is then homogenized with a hand mixer at 500 rpm for 20 seconds and then degassed for 20 minutes under nitrogen bubbling.

[0115] Then, 0.3 g of sodium hypophosphite and 3.8 mg of diethylenetriaminepentaacetic acid (DTPA) are added to the charge, followed by the successive addition of 11.4 mg of sodium persulfate and then 8.2 mg of Mohr's salt to initiate the reaction. The reaction time is 60 minutes, with a final temperature of 94°C. The resulting polymer P1b is in the form of a gel. It can then be granulated and then dried in an air stream at 70°C for 60 minutes to obtain polymer composition CP1b. The dried granules of polymer composition CP1b are then milled to obtain a powder with a particle size of less than 1.7 mm. The resulting polymer composition CP1b is 100% water-soluble and contains polymer P1b with a molar mass of 1,250,000 Da.

[0116] II. Synthesis of polymer P2:

[0117] (Example 3) (P2a: Counterexample): Synthesis of polymer P2a Polymer P2a is synthesized by radical polymerization via gel route from an aqueous charge containing 30.6% by weight of monomers according to the following protocol: 79 g of acrylic acid, 403 g of acrylamide at a concentration of 50% by weight in water, and 70 g of sodium chloride are introduced into a 1.5 L beaker. The charge is neutralized with 87 g of sodium hydroxide at a concentration of 50% by weight in water so that the pH is between 6.5 and 7.5. The charge is then cooled to 0 °C and placed in a Dewar flask. 1.5 g of azobisisobutyronitrile are then introduced into the charge, which is homogenized with a hand mixer at 500 rpm for 20 seconds and then degassed for 20 minutes under nitrogen bubbling.

[0118] Then, 0.23 g of sodium hypophosphite and 3.8 mg of diethylenetriaminepentaacetic acid (DTPA) are added to the charge, followed by the successive addition of 11.4 mg of sodium persulfate and then 8.2 mg of Mohr's salt to initiate the reaction. The reaction time is 60 minutes, with a final temperature of 94°C. The resulting polymer P2a is in the form of a gel. It can then be granulated and then dried in an air stream at 70°C for 60 minutes. The dried granules of polymer P2a are then milled to obtain a powder with a particle size of less than 1.7 mm. The resulting polymer P2a is 100% water-soluble and has a molar mass of 1,800,000 Da.

[0119] (Example 4) (P2b: present invention): Synthesis of polymer P2b Polymer P2b is synthesized by a radical polymerization method via gel route from an aqueous charge containing 30.0% by weight of monomers according to the following protocol: 65 g of acrylic acid, 430 g of acrylamide at a concentration of 50% by weight in water, and 70 g of sodium chloride are introduced into a 1.5 L beaker. The charge is neutralized with 72 g of sodium hydroxide at a concentration of 50% by weight in water so that the pH is between 6.5 and 7.5. The charge is then cooled to 0 °C and placed in a Dewar flask. 1.5 g of azobisisobutyronitrile are then introduced into the charge, which is homogenized with a hand mixer at 500 rpm for 20 seconds and then degassed under nitrogen bubbling for 20 minutes.

[0120] Then, 20 mg of sodium hypophosphite and 3.8 mg of diethylenetriaminepentaacetic acid (DTPA) are added to the charge, followed by the successive addition of 11.4 mg of sodium persulfate and then 8.2 mg of Mohr's salt to initiate the reaction. The reaction time is 60 minutes, with a final temperature of 94°C. The resulting polymer P2b is in the form of a gel. It can then be granulated and then dried in an air stream at 70°C for 60 minutes. The dried granules of polymer P2b are then milled to obtain a powder with a particle size of less than 1.7 mm. The resulting polymer P2b is 100% water-soluble and has a molar mass of 12,000,000 Da.

[0121] III. Preparation of Aggregates In the following examples, iron ore agglomerates were prepared using the binding compositions described herein, with the exact compositions and amounts shown in Table 2. Compositions according to the invention ("Invention") and counter-example ("CEx") compositions outside the scope of the invention were also prepared. The amount of binder (wt %) shown in Table 2 is based on the total weight of the iron ore concentrate. The iron ore concentrate used in the examples in Table 2 is hematite ore concentrate.

[0122] Table 1 below shows the nature of the components that may be present in the binding composition.

[0123] [Table 1]

[0124] In a first step, to prepare the agglomerates, the binding composition is mixed with the dried ore concentrate and homogenized with the required amount of water (water content between 2% and 5% by weight). The ore concentrate is mixed with the binding composition using a KitchenAid® type mixer (for up to 3 kg of concentrate) and a Hobart® type mixer (for more than 3 kg of concentrate).

[0125] After a mixing time of between 2 and 4 minutes, the ore concentrate is deposited into the inlet hopper of a tangential wheel compactor, which may be either a SAHUT-CONREUR, EURAGGLO, or KOMAREK. 3 10cm from 3 The finished aggregates, with a volume between 0.5 and 0.6 cm and a size between 3.5 and 4.5 cm, are collected at the exit of the compactor. To ensure complete drying, these aggregates are placed in an oven at 105°C for 2 to 4 hours (if more inorganic binder is known, the heating time should be extended).

[0126] In each case, the number of falling aggregates and dry strength of the resulting aggregates were measured, and the results are summarized in Table 2.

[0127] As illustrated in Table 2, different comparative bonding compositions (CEx1 to CEx10) and those according to the invention (C1 to C5) were produced. They all consist of an inorganic binder LI and two organic binders, the previously synthesized polymer composition CP1 and polymer P2. In each case, the bonding compositions were produced by blending through a mixture that allowed homogenization of the three components.

[0128] Methods for making ore agglomerates are generally known to those skilled in the art. Different green ore agglomerates were produced to test different binding compositions.

[0129] Number of wet drops (NWD) The wet drop count was determined by repeatedly dropping an agglomerate from a height of 46 cm onto a horizontal steel plate until a visible crack appeared on the pellet surface. The number of drops required for the pellet to reach the break / crack point was determined. This measurement was performed on 20 pellets. The average of the 20 measurements is called the wet drop count (NWD).

[0130] Dry compressive strength (DCS) 8cm 3 10cm from 3Twenty unfired pellets, each measuring 3.5 cm to 4.5 cm in volume, were placed in a 105°C oven for 2 to 4 hours to dry thoroughly. After drying, the dried pellets were placed individually in a standard SCAINE brand measuring device. The maximum force required to crack the pellet was determined. The average of these 20 measurements is called the "Dry Compressive Strength" (DCS).

[0131] [Table 2]

[0132] Cold agglomeration applications require the agglomerates to have a dry hardness of more than 250 kg, so that manufacturers can add these agglomerates directly to very high temperature furnaces (blast furnaces and electric furnaces).

[0133] Table 2 shows that the aggregates of Examples C1 to C4, which use the binding composition according to the invention, compact better and have a higher resistance than the aggregates of Comparative Examples CEx1 to CEx5.

[0134] Effective compaction provides a very important aggregate surface condition for manufacturers, since the cells of the rolling wheels are not blocked by the freshly obtained uncompacted material. In addition, good compaction avoids the occurrence of grainy and / or uneven surfaces that cause an increase in the abrasion index, which leads to a decrease in the marketable particle size of the pellets and an increase in the dust content in the oven and during handling. The resistance and plasticity of the aggregates make it possible to avoid breakage and therefore reduce the tumbling index.

[0135] The dry compressive strength for the tests of the aggregate compositions C1 to C4 according to the invention is improved compared to the tests of the comparative bonded compositions CEx1 to CEx5. This parameter is essential for manufacturers, as it allows them to know the behavior of the aggregates in the furnaces at very high temperatures, and an increase in the dry compressive strength will prevent the aggregates from breaking in the columns of the blast furnace and / or electric furnace, and therefore the loss of productivity due to the presence of an excessive content of fines.

[0136] The number of agglomerate drops is also very important in cold agglomeration applications to avoid agglomerate breakage before complete drying, which would lead to increased fines and reduced agglomerate dry strength.

[0137] In comparison, the binder compositions C1, C2 and C3 make it possible to obtain the required values ​​in cold agglomeration applications. It can also be seen that the choice of molecular weight of the polymers P1 and P2 is important in order to have good physical properties. The binder compositions according to the invention show their effectiveness even at low application rates, which is important for manufacturers, since the cold agglomeration method makes it possible to reduce the logistics and production costs of the agglomerates.

[0138] Testing of the comparative bonding compositions CEx1 to CEx5 shows that it is essential to work with bonding compositions of the polymer compositions CP1 and P2 according to the invention.

Claims

1. A binding composition for producing ore agglomerates, comprising at least two distinct organic binders CP1 and P2: a polymer composition CP1 comprising a nonionic or anionic water-soluble synthetic polymer P1 having a weight-average molecular weight between 500,000 and 3 million daltons, a nonionic or anionic water-soluble synthetic polymer P2 having a weight average molecular weight of more than 2 million daltons, Including, The polymer composition CP1 and the polymer P2 are both present in the form of solid particles, P1 is - at least 1% by weight of a polymer P3 comprising at least one hydrophobic monomer, or - at least one hydrophobic monomer obtained by a gel polymerization process of at least one nonionic or anionic monomer in the presence of Polymer composition CP1 comprises 0.1% to 20% by weight of at least one polymerized hydrophobic monomer. Binding composition.

2. 2. The bonding composition according to claim 1, characterized in that it comprises at least 50% by weight of the polymer composition CP1.

3. 3. A bonding composition according to claim 1, characterized in that the polymer P1 comprises at least 50 mol % of at least one non-ionic monomer.

4. 4. The bonding composition according to claim 1, wherein the polymer P1 is non-ionic.

5. 5. The bonding composition according to claim 3 or 4, characterized in that the nonionic monomer P1 is selected from the group comprising acrylamide, methacrylamide, N-vinylformamide (NVF), N-vinylacetamide, N-vinylpyridine, N-vinylpyrrolidone (NVP), N-vinylimidazole, N-vinylsuccinimide, acryloylmorpholine (ACMO), acryloyl chloride, glycidyl methacrylate, glyceryl methacrylate, diacetone acrylamide, hydroxyalkyl(meth)acrylates, aminoalkyl(meth)acrylates, aminoalkyl(meth)acrylamides, thioalkyl(meth)acrylates and mixtures thereof.

6. 6. A bonding composition according to claim 3, wherein at least one nonionic monomer of the polymer P1 is acrylamide.

7. 7. A bonding composition according to claim 1, wherein the polymer P1 is a copolymer of acrylamide and sodium acrylate.

8. The polymer P1 is C 8 ~C 16 8. A bonding composition according to any one of claims 1 to 7, characterized in that it comprises at least one hydrophobic monomer chosen from haloalkyl derivatives of methacrylamidodimethylaminopropyl containing alkyl chains, ethoxylated behenyl methacrylate, diethylacrylamide, n-tert-butylacrylamide and mixtures thereof.

9. 9. A bonding composition according to claim 1, characterized in that the polymer P3 comprises between 10% and 90% by weight of at least one hydrophobic monomer.

10. 10. A bonding composition according to claim 1, characterized in that the polymer P3 is a terpolymer of diethylacrylamide, n-tert-butylacrylamide and sodium 2-acrylamido-2-methylpropanesulfonate.

11. 11. A bonding composition according to claim 1, characterized in that the polymer P3 is functionalized at the end of the polymer chain with at least one group selected from hydroxyl, cyano, amine, phosphate, phosphonate, sulfate, sulfonate, xanthate, trithiocarbonate, dithiocarbamate and dithioester.

12. 12. The bonding composition according to claim 1, wherein the polymer P3 does not contain any carbon-carbon double bonds.

13. 13. A bonding composition according to claim 1, characterized in that the polymer P2 is a copolymer containing between 5 mol% and 100 mol% sodium acrylate.

14. 14. The bonding composition according to claim 1, wherein the polymer P2 has a weight average molecular weight greater than the weight average molecular weight of the polymer P1.

15. 15. An ore aggregate comprising between 2,000 ppm and 50,000 ppm of the binding composition of any one of claims 1 to 14, based on the mass of the ore aggregate.

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