Bonding composition for ore agglomerates

Abstract

The present invention relates to a binding composition for the manufacture of ore agglomerates comprising at least the following two different organic binders CP1 and P2:-a polymer composition CP1 comprising a nonionic or anionic water-soluble synthetic polymer P1, P2 having a weight average molecular weight of 500,000 to 3 million Daltons, 5-a nonionic or anionic water-soluble synthetic polymer P2 having a weight average molecular weight of greater than 2 million Daltons wherein the polymer composition CP1 and the polymer P2 are both present in the form of solid particles, wherein P1 is obtained from at least one non-ionic or anionic 10 monomer by a gel polymerization process in the presence of:-at least 1% by weight of a polymer P3 comprising at least one hydrophobic monomer, or-at least one hydrophobic monomer, said polymer composition CP1 comprising 0.1% to 20% by weight of at least one 15 hydrophobic monomer,-at least 1% by weight of a polymer P3 comprising at least one hydrophobic monomer, or-at least 1% by weight of a polymer composition CP2 comprising at least one hydrophobic monomer, the hydrophobic monomer is polymerized. The invention also relates to an ore aggregate containing from 2,000 to 50,000 ppm of such a binding composition.

Description

Technical Field

[0001] The present invention belongs to the technical field of ore agglomerates. The present invention relates to a binding composition which is particularly used to improve the agglomeration step for obtaining low-temperature ore agglomerates. The binding composition comprises a mixture of at least two organic polymer binders. The present invention also relates to an ore agglomerate containing the binding composition as a product. Prior Art

[0002] Most metals are obtained from ores that occur naturally underground or in mines. In the first stage of the metal recovery process, the element of interest, i.e., the metal (such as iron for steelmaking), is recovered from the ore melted in a blast furnace. For direct feeding into the blast furnace, the ore of the element of interest must be in a standard form with a relatively large size. If not, the ore particles need to be converted into agglomerates larger than the particle size. Agglomeration is a process based on the adhesion of ore particles to each other. There are five agglomeration techniques in metallurgy: briquetting, pelletizing, extrusion, granulation, and sintering. These techniques are known and described in many documents, such as the work "Agglomeration in Industry" by Wolfgang Pietsch, or, in particular, patent EP 0097486. Nowadays, the increasing use of low-quality ores forces manufacturers to grind the ores finer, which makes the agglomeration step essential.

[0003] In this agglomeration step, an adhesive or binding composition must be used to ensure that the agglomerates have good physical properties, such as mechanical strength. The "adhesive" or "binding composition" enables the optimization of the adhesion between ore particles, thereby forming agglomerates with sufficient mechanical properties to resist the vibrations and movements experienced during various processing operations.

[0004] Conventionally used adhesives include cement (Portland cement), clay, especially bentonite, starch, cellulose, molasses (optionally used in combination with lime), etc. There are some problems with using these adhesives because they contain a large amount of impurities harmful to industrial processes (such as sulfur impurities in the steel industry), and / or they result in poor physical properties of the agglomerates. In recent years, manufacturers have developed new binding compositions to counteract these adverse effects.

[0005] Documents US 5,002,607 and EP 2,548,978 describe methods for producing agglomerates using a binding composition comprising at least one organic synthetic polymer and at least one inorganic binder.

[0006] US 5,833,937 relates to a method which includes a binding step that comprises sequentially adding an anionic polymer solution and a cationic polymer solution to fine mineral powder.

[0007] Generally, the method for forming aggregates such as iron ore pellets is as follows: Add a binder to the crushed ore and stir in the presence of a small amount of water to form a wet mixture, then shovel up the mixture to form (wet) green pellets. Then, these green pellets are fired in a kiln with an inlet temperature of 200 - 400 °C and a final temperature approaching 1400 °C. For example, the document EP 0 225171 discloses such a process for forming iron ore pellets.

[0008] In order for the final aggregates to have good physical properties, the roasting step is crucial. However, in terms of fossil substances, this step is very energy-consuming. This has a considerable impact on both the ecology and economy of the aggregation equipment.

[0009] Given the current energy situation, it is crucial to find sustainable and effective solutions in order to obtain high-quality aggregates, that is, to meet the physical properties expected by this technology while taking into account productivity and energy savings.

[0010] In order to limit the environmental impact of the production of these aggregates, manufacturers have found a solution, that is, to agglomerate the ore at low temperature (i.e., the firing temperature does not exceed 250 °C). Unfortunately, based on the above-mentioned binder composition, this process cannot obtain the expected physical properties of the aggregates. The aggregates even crack before reaching production equipment such as blast furnaces. Their handling becomes difficult, and their storage is also difficult.

[0011] The present invention overcomes the disadvantages of the prior art by disclosing a binder composition for improving the agglomeration step, thereby allowing the production of ore aggregates with satisfactory physical properties at low temperature. Summary of the Invention

[0012] The present invention relates to a binder composition for generally producing ore aggregates at low temperature, which comprises at least the following two different organic binders (polymer composition CP1 and polymer P2, which have different organic binder functions):

[0013] - Polymer composition CP1, which comprises a non-ionic or anionic water-soluble synthetic polymer P1 with a weight-average molecular weight of 500,000 to 3 million Daltons,

[0014] - A non-ionic or anionic water-soluble synthetic polymer P2 with a weight-average molecular weight of greater than 2 million Daltons,

[0015] Both the polymer composition CP1 and the polymer P2 exist in the form of solid particles,

[0016] wherein P1 is obtained by a gel polymerization method from at least one non-ionic or anionic monomer in the presence of the following substances:

[0017] - a polymer P3 having a weight of at least 1% by weight relative to P1, the polymer P3 containing at least one hydrophobic monomer, or

[0018] - at least one hydrophobic monomer,

[0019] The polymer composition CP1 comprises 0.1% to 20% by weight of at least one hydrophobic monomer, and the hydrophobic monomer is polymerized.

[0020] Another aspect of the present invention relates to an ore aggregate which, relative to the weight of the ore aggregate, comprises 2,000 to 50,000 ppm of the binder composition. Summary of the Invention

[0022] Definitions and Generalizations

[0023] In the present application, the term "polymer" refers to homopolymers and copolymers of at least two different monomers.

[0024] As used herein, the term "water-soluble polymer" refers to a polymer which, when dissolved by stirring at a concentration of 20 g / L in deionized water at 25 °C for 4 hours, gives an aqueous solution free of insoluble particles. -1 When dissolved by stirring at a concentration of 20 g / L in deionized water at 25 °C for 4 hours, it gives an aqueous solution free of insoluble particles.

[0025] "Anionic polymer" refers to a polymer containing at least one anionic monomer and optionally containing at least one non-ionic monomer. "Non-ionic polymer" refers to a polymer containing only one or more non-ionic monomers. Generally, a polymer containing monomers refers to a polymer obtained by polymerization of molecules of a plurality of such monomers.

[0026] As used herein, the term "hydrophilic monomer" refers to a monomer which, when measured at a temperature of 25 °C and a pH value between 6 and 8, has an octanol / water partition coefficient Kow of less than 1.

[0027] The term "hydrophobic monomer" refers to a monomer which, when measured at a temperature of 25 °C and a pH value between 6 and 8, has an octanol / water partition coefficient Kow of greater than 1.

[0028] The octanol / water partition coefficient Kow is defined as follows:

[0029]

[0030] where [monomer]octanol = the equilibrium monomer concentration in n-octanol, in g / L; [monomer]water = the equilibrium monomer concentration in water, in g / L.

[0031] According to the present invention, "low temperature" means a temperature not exceeding 250 °C.

[0032] In the present application, the term "agglomerate" relates to a product produced by an agglomeration technique selected from granulation, sintering, spheronization, briquetting or extrusion.

[0033] The "solid particles" according to the invention are generally defined by their particle size. The median particle size (D 50 ) of a plurality of solid particles is defined as the maximum dimension of the particles (for spherical particles, it is the diameter), where half of the particle population is below this value. The particle size refers to the average diameter measured using a laser diffraction particle size analyzer according to conventional techniques known to those skilled in the art. An example of an instrument for measuring the average diameter is the Mastersizer from Malvern Instruments.

[0034] According to the invention, a numerical range includes a lower limit and an upper limit. Thus, the numerical ranges "between 0.1 and 1.0" and "0.1 to 1.0" include 0.1 and 1.0.

[0035] According to the invention, the weight-average molecular weight of a polymer is determined by measuring the intrinsic viscosity. The intrinsic viscosity can be measured by any method known to those skilled in the art. Specifically, it is calculated by a method of measuring viscosity in solution, including determining the reduced viscosity values at different concentrations according to a graphical method, which includes plotting the reduced viscosity values (ordinate) against the concentration (abscissa), and then extrapolating the curve to zero concentration. The intrinsic viscosity value can be read on the ordinate or using the least squares method.

[0036] Next, the weight-average molecular weight is determined by the Mark-Houwink equation:

[0037] [η]=KM α

[0038] where [η] represents the intrinsic viscosity of the polymer determined by the solution viscosity measurement method,

[0039] K represents an empirical constant,

[0040] M represents the molecular weight of the polymer,

[0041] α represents the Mark-Houwink coefficient.

[0042] α and K depend on the specific polymer-solvent system. Tables known to those skilled in the art give the values of α and K according to the polymer-solvent system.

[0043] Polymer composition CP1 and polymer P1

[0044] The binder composition according to the invention comprises a polymer composition CP1, which comprises a non-ionic or anionic water-soluble polymer P1, the weight-average molecular weight of which is from 500,000 to 3 million (= 3.106 )Dalton, more preferably from 500,000 to 2,500,000 Daltons, even more preferably from 500,000 to 2,000,000 Daltons.

[0045] Advantageously, the anionic monomers of the water-soluble polymer P1 are preferably selected from monomers having a vinyl functional group, in particular acrylic acid, maleic acid, fumaric acid, malonic acid, itaconic acid or allyl compounds. It may also contain at least one carboxylate, phosphonate, phosphate, sulfonate or other anionic group. Preferred monomers belonging to this category are, for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, acrylamidoundecanoic acid, 3-acrylamido-3-methylbutyric acid, maleic anhydride, 2-acrylamido-2-methylpropanesulfonic acid (ATBS), vinylsulfonic acid, vinylphosphonic acid, 2-sulfoethyl methacrylate, sulfopropyl methacrylate, sulfopropyl acrylate, 1-allylphosphonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanedisulfonic acid, its salts, and mixtures thereof. Preferably it is acrylic acid or itaconic acid. Even more preferably it is acrylic acid.

[0046] Thus, in a specific embodiment of the present invention, the anionic monomers can be salted.

[0047] "Salting" means that at least one acid functional group of the anionic monomer is replaced by a salt capable of neutralizing the negative charge of the acid functional group. In other words, the non-salted form corresponds to the acid form of the monomer, for example, R-C(=O)-OH in the case of a carboxylic acid functional group; while the neutralized form of the monomer corresponds to R-C(=O)-O - X + form, where X + corresponds to a positively charged salt. The neutralization of the acid functional group of the water-soluble polymer can be partial neutralization or complete neutralization. The salted form advantageously corresponds to a salt of an alkali metal (Li, Na, K, etc.), an alkaline earth metal (Ca, Mg, etc.) or ammonium (e.g., ammonium ion or tertiary ammonium). The preferred salt is sodium salt. The salting can be carried out before or after polymerization.

[0048] As explained above, this does not exclude the presence of at least one anionic monomer unit containing an (unneutralized) carboxylic acid functional group in the polymer P1. In other words, it is possible to have simultaneously an anionic monomer containing a carboxylic acid functional group and the same monomer containing a carboxylate functional group.

[0049] Even more preferably, the polymer P1 contains at least one anionic monomer containing a carboxylate functional group, and the carboxylate functional group is a salt of acrylic acid. Advantageously, the polymer P1 contains at least sodium acrylate as a monomer unit.

[0050] In a preferred embodiment of the present invention, the water-soluble polymer P1 does not contain monomer units having a sulfonic acid functional group or its salt, such as acrylamidotert-butylsulfonic acid (ATBS), allylsulfonic acid or methallylsulfonic acid.

[0051] Advantageously, the water-soluble polymer P1 contains less than 50 mol% of anionic monomers, preferably 10 to 40 mol%, more preferably 15 to 30 mol%.

[0052] Advantageously, the non-ionic monomers can be particularly selected from water-soluble vinyl monomers. The non-ionic monomers are selected from, for example, acrylamide, methacrylamide, N-vinylformamide (NVF), N-vinylacetamide, N-vinylpyridine, N-vinylpyrrolidone (NVP), N-vinylimidazole, N-vinylsuccinimide, acryloylmorpholine (ACMO), acryloyl chloride, glycidyl methacrylate, glycerol methacrylate, diacetoneacrylamide, (meth)acrylic acid hydroxyalkyl esters (alkyl is advantageously C1-C3), (meth)acrylic acid aminoalkyl esters (alkyl is advantageously C1-C3), aminoalkyl (meth)acrylamides (alkyl is advantageously C1-C3), (meth)acrylic acid thioalkyl esters (alkyl is advantageously C1-C3) and mixtures thereof. Preferably, at least one non-ionic monomer of the polymer P1 is acrylamide.

[0053] The polymer P1 advantageously contains at least 50 mol%, preferably 60 to 90 mol%, even more preferably 70 to 85 mol% of at least one non-ionic monomer.

[0054] The sum of the monomers is equal to 100% of the polymer P1.

[0055] According to a preferred embodiment, the polymer P1 is non-ionic.

[0056] Preferably, the polymer P1 is a copolymer of acrylamide and sodium acrylate, which preferably contains 10 to 40 mol%, even more preferably 15 to 30 mol% of sodium acrylate, and the sum of the two monomers is preferably equal to 100% of the polymer P1.

[0057] In an embodiment of the present invention, the polymer P1 contains hydrophobic monomers.

[0058] The hydrophobic monomers of the polymer P1 have a Kow partition coefficient greater than 1 and are preferably selected from the following compounds:

[0059] -(Meth)acrylates having an alkyl and / or aralkyl and / or ethoxylated and / or propoxylated chain; (meth)acrylamide derivatives having an alkyl and / or aralkyl and / or dialkyl and / or ethoxylated and / or propoxylated chain; anionic hydrophobic derivatives of (meth)acryloyl; and anionic monomer derivatives of (meth)acrylamide having a hydrophobic chain;

[0060] -n-hexyl (meth)acrylate, n-octyl (meth)acrylate, octyl (meth)acrylamide, n-tert-butyl (meth)acrylamide, lauryl (meth)acrylate, (laurylmethyl)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, brassidyl (meth)acrylamide, brassidyl (meth)acrylamide and combinations thereof;

[0061] -A hydrophobic monomer corresponding to the following general formula

[0062] CH2=CR 1 -COO-(EO) n -(PO) m -R 2 ,

[0063] wherein R 1 is hydrogen or methyl; n is a number of at least 2, preferably from 6 to 100, even more preferably from 10 to 40; m is a number from 0 to 50, preferably from 0 to 20, EO is an ethylene oxide group (-CH2-CH2-O-), PO is a propylene oxide group (-CH2-CH(CH3)-O-), R 2 is a C8-C 30 alkyl or a C8-C 30 aralkyl, and n + m is preferably from 6 to 100 or from 10 to 40. They are preferably straight-chain alkyls.

[0064] Among the hydrophobic monomers having an alkyl chain in P1, especially in (meth)acrylates and (meth)acrylamide derivatives, the alkyl is advantageously C1-C5, more advantageously C1-C 3。 They are preferably straight-chain alkyls. Thus, dialkyl contains two alkyls, advantageously C1-C5. The aralkyl of these monomers is advantageously C8-C 30 .

[0065] More preferably, the hydrophobic monomers of P1 are selected from the following compounds: those containing a C8-C 16Halogenated alkyl (preferably bromoalkylated) derivatives of methacrylamidodimethylaminopropyl of the alkyl chain, ethoxylated behenyl methacrylate, diethylacrylamide, n-tert-butylacrylamide, and mixtures thereof.

[0066] Advantageously, according to a preferred embodiment, polymer P1 comprises at least one hydrophobic monomer selected from the group consisting of C8-C 16 Halogenated alkyl derivatives of methacrylamidodimethylaminopropyl of the alkyl chain, ethoxylated behenyl methacrylate, diethylacrylamide, n-tert-butylacrylamide, and mixtures thereof.

[0067] Polymer P1 can be linear or structured. A "structured polymer" refers to a non-linear polymer having side chains such that when the polymer is dissolved in water, a strongly entangled state is obtained, resulting in a very high low-shear viscosity. Structuring can be achieved by 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. For example, sodium allylsulfonate, sodium methallylsulfonate, sodium methallyldisulfonate, methylene bisacrylamide, diallylamine, triallylamine, triallylammonium chloride, or tetraallylammonium chloride can be mentioned. Structuring can also be achieved by at least one macroinitiator (such as a polyperoxide or a polyazo compound) or at least one transfer polymerization agent (such as a polythiol).

[0068] Polymer P1 can also be structured using controlled radical polymerization (CRP) techniques, more specifically a technique of the reversible addition-fragmentation chain transfer (RAFT) type.

[0069] Polymer P1 can be structured into a comb shape, a star shape, or any other structure known to those skilled in the art. The structured polymer P1 remains water-soluble.

[0070] Advantageously, polymer P1 is structured into a star shape, i.e., it has a central part (referred to as the core) and arms based on polymers that radially extend from the central part.

[0071] According to the present invention, the polymer composition CP1 is in the form of solid particles, and the median particle size (D 50 ) of a plurality of solid particles is generally greater than 500 micrometers (μm).

[0072] Preferably, polymer P1 is obtained by a gel polymerization method of at least one nonionic or anionic monomer in the presence of:

[0073] - a polymer P3 of at least 1% by weight of at least one hydrophobic monomer, or

[0074] - At least one hydrophobic monomer,

[0075] The polymer composition CP1 comprises from 0.1% to 20% by weight of at least one hydrophobic monomer, which is polymerized.

[0076] In one embodiment of the invention, the polymer P1 is obtained by a gel polymerization process of at least one non-ionic 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 comprising from 0.1% to 20% by weight of at least one hydrophobic monomer, which is polymerized within the polymer P3. In this embodiment, the polymer composition CP1 consists of the polymer P1 and the polymer P3.

[0077] In another embodiment of the invention, the polymer P1 is obtained by a gel polymerization process of at least one non-ionic or anionic monomer in the presence of at least one hydrophobic monomer, the polymer composition CP1 comprising from 0.1% to 20% by weight of at least one hydrophobic monomer, which is polymerized within the polymer P1. In this embodiment, the polymer P1 comprises the at least one hydrophobic monomer. In this embodiment, the polymer composition CP1 consists of the polymer P1.

[0078] According to the invention, "A and / or B" means A, or B, or A and B.

[0079] The gel polymerization in the process of the invention is carried out in a radical manner. This includes radical polymerization using ultraviolet light, azo, redox or thermal initiators, as well as controlled radical polymerization (CRP) techniques, especially polymerization of the RAFT type.

[0080] At least one transfer agent can be used. It can be selected in particular from sulfur compounds such as mercaptoacetic acid, mercaptoalcohol 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 with an -S-CS- functional group. Compounds of the xanthate (-S-CS-O-), dithiocarboxylate (-S-CS-carbon), trithiocarbonate (-S-CS-S-) or dithiocarbamate (-S-CS-nitrogen) type can be mentioned in particular. Among the compounds of the xanthate type, O-ethyl-S-(1-methoxycarbonylethyl)xanthate can be advantageously used because of its compatibility with acrylic monomers.

[0081] The polymerization initiator used to obtain polymer P1 can be any compound that dissociates into free radicals under polymerization conditions, such as: organic peroxides, hydroperoxides, hydrogen peroxide, persulfates, azo compounds, and redox catalysts. Water-soluble initiators are preferably used. In some cases, it is advantageous to use a mixture of multiple polymerization initiators, such as a mixture of a redox catalyst and an azo compound.

[0082] The polymerization initiator is used in a usual amount. For example, relative to the monomers to be polymerized, the amount can be 0.0001 to 2% by weight, preferably 0.001 to 1% by weight.

[0083] As the oxidant component, the redox catalyst preferably contains at least one of the above compounds. As the reducing component, the redox catalyst is preferably selected from ascorbic acid, glucose, sorbose, bisulfite, sulfite, thiosulfate, dithionite, metabisulfite, alkali metals, metal salts (such as salts in the form of iron(II) ions or silver ions), or sodium hydroxymethanesulfinate. The reducing component of the redox catalyst preferably used is Mohr's salt (NH4)2Fe(SO4)2·6H2O.

[0084] For example, based on the amount of monomers used in the polymerization reaction, 1 mol% of the reducing component of the redox catalyst system and 2 mol% of the oxidizing component of the redox catalyst can be used at 5x10 -6 One or more water-soluble azo initiators can also be used instead of the oxidant component of the redox catalyst. -5 The polymerization of the water-soluble polymer P1 is carried out under anaerobic conditions, where the initiator is introduced into the solution to be polymerized in a suitable order known to those skilled in the art. The initiator can be introduced in the form of a solution in an aqueous medium or in the form of a solution in an organic solvent.

[0085] All components are advantageously dissolved, and more preferably dissolved in water.

[0086] At the beginning of the polymerization reaction, the reaction mixture is heated or warmed up according to the selected starting conditions (exothermic reaction). Advantageously, due to the heat released by the polymerization reaction, the temperature of the reaction mixture rises from 80°C to 150°C, preferably from 80°C to 100°C. The polymerization reaction is advantageously carried out under atmospheric pressure. Those skilled in the art know how to select suitable equipment to achieve the best polymerization reaction.

[0087] At the end of the polymerization reaction, the polymer gel P1 is allowed to age, generally for at least 60 minutes.

[0088]

[0089] ​"Aging" means leaving the gel in the polymerization reactor at the final polymerization temperature.

[0090] The polymerization product obtained is usually a viscous polymer gel P1, which is then granulated. Granulation involves cutting the gel into small pieces. According to the present invention, the average size of these gel pieces is advantageously less than 1 cm, more advantageously 4 to 8 mm. Those skilled in the art know how to select suitable means to achieve the best granulation effect. The next step is to grind these gel pieces. The grinding step involves breaking large polymer particles into smaller particles. This can be achieved by shearing or mechanically crushing the particles between two hard surfaces. Different types of equipment known to those skilled in the art can be used for this purpose, such as a rotor mill (where the particles are crushed on the pressing blades of a rotating part) or a roll mill (where the particles are crushed between two rotating rolls). Then, the sieving after grinding aims to remove medium-sized particles, too small particles or too large particles according to the specifications. The next step is to dry the polymer P1. The drying means and its conditions (time + temperature) are the conventional choices of those skilled in the art. Industrially, drying is advantageously carried out using a fluidized bed or a rotary dryer, advantageously using air heated to a temperature of 70 °C to 200 °C, and the temperature of the air depends on the nature of the product and the drying time applied. The resulting product is a polymer composition CP1. The polymer composition CP1 is subsequently in powder form.

[0091] Polymer P3

[0092] According to one aspect of the present invention, the polymer P1 is preferably characterized in that it is prepared by a gel polymerization method known to those skilled in the art in the presence of a polymer P3 of at least one hydrophobic monomer at least 1% by weight. 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.

[0093] The hydrophilic monomer of the polymer P3 has a Kow partition coefficient of less than 1 and is preferably selected from 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 esters of acrylic acid, hydroxyalkyl esters of methacrylic acid and mixtures thereof; monomers having a carboxylic acid functional group and their salts, including acrylic acid, methacrylic acid, itaconic acid and maleic acid; monomers having a sulfonic acid functional group and their salts, including acrylamidotert-butylsulfonic acid (ATBS), allylsulfonic acid and methallylsulfonic acid and their salts; monomers having a phosphonic acid functional group and their salts; and mixtures thereof. Usually, 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).

[0094] The hydrophobic monomers of polymer P3 have a Kow partition coefficient greater than 1 and are preferably selected from the following compounds:

[0095] -(meth)acrylates having an alkyl and / or aralkyl and / or ethoxylated and / or propoxylated chain; (meth)acrylamide derivatives having an alkyl and / or aralkyl and / or dialkyl and / or ethoxylated and / or propoxylated chain; anionic hydrophobic derivatives of (meth)acryloyl; and anionic monomer derivatives of (meth)acrylamide with a hydrophobic chain;

[0096] -n-hexyl (meth)acrylate, n-octyl (meth)acrylate, octyl (meth)acrylamide, tert-butyl (meth)acrylamide, lauryl (meth)acrylate, (laurylmethyl)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, brassidyl (meth)acrylamide, brassidyl (meth)acrylamide and combinations thereof;

[0097] -a hydrophobic monomer corresponding to the following general formula

[0098] CH2=CR 1 -COO-(EO) n -(PO) m -R 2 ,

[0099] wherein R 1 is hydrogen or methyl; n is a number of at least 2, preferably from 6 to 100, even more preferably from 10 to 40; m is a number from 0 to 50, preferably from 0 to 20, EO is an ethylene oxide group (-CH2-CH2-O-), PO is a propylene oxide group (-CH2-CH(CH3)-O-), and R 2 is a C8-C 30 alkyl or a C8-C 30 aralkyl, and n + m is preferably from 6 to 100 or from 10 to 40. They are preferably straight-chain alkyls.

[0100] Among the hydrophobic monomers of P3 having an alkyl chain, especially in (meth)acrylates and (meth)acrylamide derivatives, the alkyl is advantageously C1-C5, more advantageously C1-C3. They are preferably straight-chain alkyls. Thus, dialkyl contains two alkyls, advantageously C1-C5. The aralkyl of these monomers is advantageously C8-C 30 .

[0101] More preferably, the hydrophobic monomer of P3 is selected from the following compounds: haloalkyl (preferably bromoalkylated) derivatives of methacrylamidodimethylaminopropyl containing a C8-C 16 alkyl chain, ethoxylated behenyl methacrylate, diethylacrylamide, n-tert-butylacrylamide, and mixtures thereof.

[0102] The polymer P3 contains 10 to 100% by weight, even more preferably 10 to 90% by weight of at least one hydrophobic monomer.

[0103] Advantageously, the polymer P3 is a terpolymer of diethylacrylamide, n-tert-butylacrylamide, and sodium 2-acrylamido-2-methylpropanesulfonate.

[0104] In a preferred embodiment, the polymer P3 is functionalized at the end of the polymer chain with at least one group selected from the following: hydroxyl, cyano, amine, phosphate, phosphonate, sulfate, sulfonate, xanthate, trithiocarbonate, dithiocarbamate, and dithioester. The chain of the polymer P3 may also be non-functionalized.

[0105] Preferably, the polymer P3 does not contain any carbon-carbon double bonds.

[0106] According to this aspect of the invention, the polymer P1 is obtained under the following conditions:

[0107] - Prepare an aqueous solution of the polymer P1, which solution contains 1 to 25% by weight, advantageously 2 to 20% by weight, even more advantageously 3 to 15% by weight of the polymer P3, where % is expressed by weight relative to the total weight of the aqueous solution, the polymer P3 contains monomers selected from the above list; some water; and optionally additives, and the total mass concentration of the monomers is 10 to 60% by weight, advantageously 20 to 55% by weight, even more advantageously 25 to 50% by weight relative to the total weight of the aqueous solution. Dissolve the polymerization compound in the aqueous medium to be polymerized, for example, under stirring. The starting temperature of this solution (also called the material to be polymerized) is adjusted to between -20°C and 50°C. Advantageously, the starting temperature is adjusted to between -5°C and 30°C, and even more advantageously between 0°C and 20°C. Those skilled in the art know how to determine the pH value to be achieved, as well as the amount and selection of the pH regulator, based on the chemical properties of the polymer to be synthesized and the properties of the monomers (non-ionic, anionic, etc.).

[0108] - After dissolution, degas to eliminate any traces of residual oxygen, thanks to at least one inert gas. Usually, an inert gas is passed through the solution. Inert gases suitable for this purpose are, for example, nitrogen, carbon dioxide, or noble gases such as neon or helium. Argon can also be used.

[0109] The hydrophilic monomers present in polymer P3 can promote the dissolution of polymer P3 in water, even when it mainly contains hydrophobic monomers. In this case, the hydrophilic monomers act as cosolvents for polymer P3. Thus, the polymerization solution does not contain any insoluble components. Generally, polymer P1 is water-soluble, while polymer P3 is not necessarily water-soluble.

[0110] According to a second aspect of the present invention, polymer P1 is obtained by a gel polymerization method in the presence of at least one hydrophobic monomer. In this specific case, polymer P1 contains, in addition to its anionic and / or nonionic water-soluble monomers as described above, at least one hydrophobic monomer.

[0111] The hydrophobic monomers are generally selected from the same list of hydrophobic monomers as described above for P3. To this end, 1% to 20% of at least one hydrophobic monomer is preferably introduced into the polymer mass of P1. However, it is preferred that polymers P3 and P1 do not contain any cationic monomers or any zwitterionic monomers.

[0112] According to this aspect of the invention, optionally, such or these hydrophobic monomers are brought into contact with one or more surfactants.

[0113] A "surfactant" refers to a substance capable of emulsifying oil in water. Generally, surfactants are considered to refer to compounds with a hydrophilic-lipophilic balance (HLB) value greater than or equal to 10.

[0114] The hydrophilic-lipophilic balance value (HLB) of a compound is a measure of its hydrophilic or lipophilic degree, as described by Griffin in 1949, which is determined by calculating values for different regions of the molecule. Griffin assigned a dimensionless number between 0 and 20 to provide information about water solubility and oil solubility. A substance with an HLB value of 10 is distributed between two phases such that the hydrophilic groups (molecular weight Mh) protrude completely into the water, while the hydrophobic groups (molecular weight Mp) are adsorbed in the non-aqueous phase. The HLB value of a substance with a total molecular weight of M and a hydrophilic part molecular weight of Mh is given by the following formula:

[0115] HLB = 20(Mh / Mp)

[0116] The surfactant can be any suitable surfactant selected from anionic surfactants, cationic surfactants, nonionic surfactants, and combinations thereof. In some embodiments, the surfactant can be present in dimer form. For example, the surfactant can comprise 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 surfactant mixture can be selected from the following 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 oleyl alcohol; heptaethoxylated lauryl alcohol; castor oil ethoxylated with 40 moles of ethylene oxide; polyethoxylated alkylphenols; polyethoxylated cetyl ethers; quaternary amine derivatives; sodium dodecyl sulfate; condensation products of fatty alcohols and ethylene oxide; condensation products of alkylphenols and ethylene oxide; condensation products of amino fatty acids having 5 or more ethylene oxide units; triphenylvinylphenol ethylene oxide; alkyl polyglucosides; amine oxides, glucamides; alkylbenzene sulfonates, water-soluble surfactant polymers. Preferably, less than 10% by weight of the surfactant is added to the polymer material.

[0117] Polymer P2

[0118] The adhesive composition according to the present invention, in addition to the polymer composition CP1 comprising polymer P1, further comprises a nonionic or anionic water-soluble synthetic polymer P2 having a weight-average molecular weight greater than two million (2.10 6 ) Daltons. The weight-average molecular weight of the water-soluble polymer P2 is more preferably greater than five million Daltons. The weight-average molecular weight of the water-soluble polymer P2 is generally less than forty million Daltons. The polymer P2 comprises at least one nonionic or anionic monomer.

[0119] Preferably, the weight-average molecular weight of polymer P2 is greater than the weight-average molecular weight of polymer P1.

[0120] The nonionic and anionic monomers are preferably selected from the same compounds as mentioned above for P1. Advantageously, the anionic monomers can be salted as described above.

[0121] Preferably, the water-soluble polymer P2 contains 5% to 100 mol%, more preferably 10% to 70 mol%, even more preferably 20% to 50 mol% of at least one anionic monomer.

[0122] Advantageously, the water-soluble polymer P2 does not contain monomer units or their salts having a sulfonic acid functional group, such as acrylamidotert-butylsulfonic acid (ATBS), allyl sulfonic acid, and methallyl sulfonic acid.

[0123] Polymer P2 is linear or structured. The structure of polymer P2 can be structured as described above for P1. The structured P2 polymer still remains water-soluble.

[0124] Polymer P2 exists in the form of solid particles such as powders or microbeads. The powder of polymer P2 can be obtained by gel polymerization, precipitation polymerization or polymerization in an aqueous solution, followed by drum drying, spray drying or radiation drying (such as wave micro-drying or fluidized bed drying). The powder form can also be obtained by water-in-oil emulsion polymerization (inverse emulsion), followed by a distillation / concentration step and spray drying of the resulting liquid.

[0125] The P2 polymer microbeads are advantageously obtained by inverse suspension polymerization.

[0126] Preferably, polymer P2 is in the form of a powder obtained by gel polymerization or in the form of microbeads obtained by inverse suspension polymerization.

[0127] According to the present invention, polymer P2 is in the form of solid particles such that the median size (D 50 ) of a plurality of solid particles is greater than 500 micrometers (μm).

[0128] Particularly preferably, polymer P2 is a copolymer containing 5 to 100 mol% of sodium acrylate.

[0129] The binding composition according to the present invention

[0130] In order to achieve the agglomeration of ores at low temperatures, the binding composition of the present invention comprises at least two polymers having different organic binder functions: polymer compositions CP1 and P2.

[0131] According to a preferred embodiment of the present invention, the binding composition contains at least 50% by weight of polymer composition CP1.

[0132] According to a preferred embodiment of the present invention, the binding composition comprises only two different organic binders: polymer compositions CP1 and P2. According to this preferred embodiment, the binding composition preferably comprises 75 to 90% by weight of polymer composition CP1 and 10 to 25% by weight of polymer P2. The sum of the weight ratios of CP1 + P2 is equal to 100%.

[0133] According to another embodiment of the present invention, the binding composition may further comprise at least one other component of a different nature, thereby improving the physical properties of the agglomerates and even further enhancing the binding force of the composition.

[0134] One of these components can be an organic binder different from CP1 and P2, such as an epoxy resin, a polyphenol resin or a formaldehyde resin. Preferably RolkemTM Brand resin.

[0135] Thus, according to another aspect of the present invention, the binding composition comprises less than 40% by weight of the polymer composition CP1, 1 to 25% by weight of the polymer P2, and at least 50% by weight of another organic binder different from CP1 and P2, and the sum of the weight percentages of the components is equal to 100%.

[0136] The binding composition may further comprise an inorganic binder, which is advantageously in the form of solid particles and is hereinafter denoted as LI. The inorganic binder LI may be selected from sodium carbonate, sodium bicarbonate, sodium phosphate, sodium silicate, urea, calcium oxide, bentonite, and mixtures thereof. The preferred LI inorganic binder is sodium silicate. According to the present invention, the binder LI may be present in the form of solid particles such that the median size (D 50 ) is between 500 and 5000 microns, more preferably between 500 and 2000 microns.

[0137] Thus, according to an alternative embodiment of the present invention, the binding composition comprises at least 50% by weight of the inorganic binder LI, 10% to 49% by weight of the polymer composition CP1, and 0.5% to 5% by weight of the polymer P2, wherein the sum of the weight percentages of CP1 + P2 + LI is equal to 100%.

[0138] Another embodiment of the present invention relates to a binding composition comprising 10 to 40% by weight of the inorganic binder LI, 5 to 20% by weight of the polymer composition CP1, at least 50% by weight of another organic binder different from P1 and P2, and less than 5% by weight of the polymer P2, and the sum of the weight percentages of the components is equal to 100%.

[0139] The binding composition according to the present invention is formed by mixing its components, and each component is in powder form.

[0140] The binding composition particularly preferably contains less than 0.1% by weight of sulfur element.

[0141] Agglomerate

[0142] The last aspect of the present invention relates to an ore agglomerate, which advantageously contains 2,000 to 50,000 ppm of the binding composition relative to the weight of the ore agglomerate.

[0143] The agglomerate is generally formed as follows: Under stirring, in the presence of a small amount of water, the binding composition is added to the ground ore to form a wet mixture. Then, the mixture is agglomerated using a preferred agglomeration technique (granulation, sintering, spheronization, extrusion, or briquetting). Then, the obtained agglomerate is fired in a furnace at no more than 250°C.

[0144] Depending on the desired application, the agglomerates can be subjected to additional subsequent physical and / or chemical treatments, as is known to those skilled in the art. Examples

[0145] The following examples contribute to best illustrating the advantages of the present invention in a clear and non-limiting manner.

[0146] I. Synthesis of Polymer P1 and Polymer Composition CP1:

[0147] Example 1 (P1a: Comparative Example): Synthesis of a low molecular weight acrylamide homopolymer P1a by an aqueous solution route

[0148] Polymer P1a was synthesized by an aqueous liquid phase free radical polymerization method using an aqueous material containing 40.0% by weight of acrylamide monomer. The specific steps were as follows: In a 1 L jacketed reactor, 133 g of water and 6 g of sodium hypophosphite were introduced in sequence. The pH value of the aqueous phase was adjusted to between 2.0 and 3.0 using a dilute sulfuric acid solution. Then, the material was heated to between 79 and 81 °C using the jacketed reactor. When the aqueous material reached the temperature, 800 g of a 50% by weight aqueous acrylamide solution was poured in within 120 minutes. At the same time, a 6.5% by weight aqueous sodium persulfate solution was poured in within 130 minutes. After the addition of sodium persulfate was completed, the reaction was allowed to stand at the same temperature for 1 hour to reduce the content of residual monomers. The resulting polymer P1a was in the form of a viscous liquid and contained 40% by weight of the polymer. The molecular weight of polymer P1a was 100,000 Daltons.

[0149] Example 2 (CP1b and P1b: The present invention): Synthesis of polymer composition CP1b containing acrylamide / sodium acrylate copolymer P1b by adding 2% by weight of polymer P3 (which contains 83% by weight of hydrophobic monomers) to the polymer material.

[0150] In the first step, polymer P3 with the following weight composition was synthesized in an aqueous solution by a free radical polymerization reaction: 5% N-tert-butylacrylamide, 78% diethylacrylamide, 17% 2-acrylamido-2-methylpropanesulfonic acid sodium salt.

[0151] In the second step, polymer P1b was synthesized from an aqueous material containing 2 wt% of polymer P3 by a gel route and a free radical polymerization method according to the following protocol: 20 g of polymer P3 composition (361 g of a 5.5 wt% aqueous solution of polymer P3), 79 g of acrylic acid, 403 g of a 50 wt% aqueous acrylamide solution, and 70 g of sodium chloride were introduced into a 1.5 L beaker. 87 g of a 50 wt% aqueous sodium hydroxide solution was used to neutralize the material to a pH between 6.5 and 7.5. Then the material was cooled to 0 °C and then placed in a Dewar flask. Then 1.5 g of azobisisobutyronitrile was introduced into the material, which was then homogenized for 20 seconds at a speed of 500 rpm using a manual stirrer and then degassed for 20 minutes under nitrogen bubbling.

[0152] Then 0.3 g of sodium hypophosphite and 3.8 mg of diethylenetriaminepentaacetic acid (DTPA) were added to the material, and the reaction was initiated by sequentially adding 11.4 mg of sodium persulfate and then 8.2 mg of Mohr's salt. The reaction time was 60 minutes and the final temperature was 94 °C. The resulting polymer P1b was in gel form. Thus, it could be granulated and then dried in an air stream at 70 °C for 60 minutes to obtain a polymer composition CP1b. Then the dry granules of the polymer composition CP1b were ground to obtain a powder with a particle size less than 1.7 mm. The resulting polymer composition CP1b was 100% water-soluble and contained polymer P1b with a molecular weight of 1,250,000 Da.

[0153] II. Synthesis of polymer P2:

[0154] Example 3 (P2a: Comparative example): Synthesis of polymer P2a

[0155] Polymer P2a was synthesized from an aqueous material containing 30.6 wt% monomers by a gel route and a free radical polymerization process according to the following protocol: 79 g of acrylic acid, 403 g of a 50 wt% aqueous acrylamide solution, and 70 g of sodium chloride were introduced into a 1.5 L beaker. 87 g of a 50 wt% aqueous sodium hydroxide solution was used to neutralize the material to a pH between 6.5 and 7.5. Then the material was cooled to 0 °C and then placed in a Dewar flask. Subsequently, 1.5 g of azobisisobutyronitrile was introduced into the material, which was then homogenized for 20 seconds at a speed of 500 rpm using a manual stirrer and then degassed for 20 minutes under nitrogen bubbling.

[0156] Then, 0.23 g of sodium hypophosphite and 3.8 mg of diethylenetriaminepentaacetic acid (DTPA) were added to the material, and the reaction was initiated by sequentially adding 11.4 mg of sodium persulfate and then 8.2 mg of Mohr's salt. The reaction time was 60 minutes and the final temperature was 94 °C. The resulting polymer P2a was in the form of a gel. Thus, it could be granulated and then dried in an air stream at 70 °C for 60 minutes. Then, the dry granules of polymer P2a were ground to obtain a powder with a particle size of less than 1.7 mm. The resulting polymer P2a was 100% water-soluble and had a molecular weight of 1,800,000 Da.

[0157] Example 4 (P2b: of the present invention): Synthesis of polymer P2b

[0158] By the gel route, through a free radical polymerization process, polymer P2b was synthesized from an aqueous material containing 30.0 wt% monomers according to the following protocol: 65 g of acrylic acid, 430 g of a 50 wt% aqueous acrylamide solution, and 70 g of sodium chloride were introduced into a 1.5 L beaker. 72 g of a 50 wt% aqueous sodium hydroxide solution was used to neutralize the material to a pH between 6.5 and 7.5. Then, the material was cooled to 0 °C and placed in a Dewar flask. Subsequently, 1.5 g of azobisisobutyronitrile was introduced into the material, which was then homogenized for 20 s at 500 rpm using a manual stirrer and then degassed for 20 minutes under nitrogen bubbling.

[0159] Then, 20 mg of sodium hypophosphite and 3.8 mg of diethylenetriaminepentaacetic acid (DTPA) were added to the material, and the reaction was initiated by sequentially adding 11.4 mg of sodium persulfate and then 8.2 mg of Mohr's salt. The reaction time was 60 minutes and the final temperature was 94 °C. The resulting polymer P2b was in the form of a gel. Thus, it could be granulated and then dried in an air stream at 70 °C for 60 minutes. Then, the dry granules of polymer P2b were ground to obtain a powder with a particle size of less than 1.7 mm. The resulting polymer P2b was 100% water-soluble and had a molecular weight of 12,000,000 Da.

[0160] III. Manufacture of agglomerates

[0161] In the following examples, iron ore agglomerates were prepared using the binder compositions described herein, the specific composition and dosage of which are shown in Table 2. In addition, a composition according to the present invention ("the present invention") and a comparative example composition ("CEx") outside the scope of the present invention were also prepared. The binder dosages (expressed as weight percentages) given in Table 2 are based on the total weight of the iron ore concentrate. The iron ore concentrate used in the examples of Table 2 was hematite concentrate.

[0162] Table 1 below shows the properties of the elements that may be present in the binder composition.

[0163] Table 1: Organic and inorganic binders

[0164]

[0165] To prepare the above-mentioned agglomerates, in the first step, the binder composition is mixed with the dry concentrate and homogenized with the required amount of water (water content between 2% and 5% by weight). Use a mixer of type

[0166] (concentrate amount up to 3 kg) and a Hobart-type mixer (concentrate amount exceeding 3 kg) to mix the concentrate with the binder composition. 3 After mixing for 2 to 4 minutes, the concentrate is poured into the feed hopper of a tangential wheel compactor, which can be SAHUT-CONREUR, EURAGGLO or KOMAREK. The final agglomerates are recovered at the outlet of the compactor, with a size between 3.5 and 4.5 cm and a volume between 8 and 10 cm

[0167] The number of drops and the dry strength of the obtained agglomerates were measured for each case, and the results are summarized in Table 2.

[0168] As explained in Table 2, different comparative binder compositions (CEx 1 to CEx 10) and binder compositions according to the present invention (C1 to C5) were prepared. They are all composed of an inorganic binder LI and two organic binders (i.e., the previously synthesized polymer composition CP1 and polymer P2). In each case, the binder composition was produced by blending the mixture to homogenize the three components.

[0169] The process for preparing ore agglomerates is well known to those skilled in the art. Different green ore agglomerates were prepared to test different binder compositions.

[0170] Wet number of drops (NWD)

[0171] The method for determining the wet number of drops is as follows: The agglomerates are repeatedly dropped from a height of 46 cm onto a horizontally placed steel plate until visible cracks appear on the surface of the pellets. Thus, the number of times the pellet drops to its fracture / cracking point is determined. This measurement is carried out on 20 pellets. The average value of these 20 measurements is called the wet number of drops (NWD).

[0172] Dry compressive strength (DCS)

[0173] Twenty pellets with a size between 3.5 and 4.5 cm and a volume between 8 and 10 cm 3The green pellets are placed in an oven at 105 °C and dried for 2 to 4 hours until completely dry. After drying, the dried pellets are individually placed in a measuring device of the standard SCAINE brand. The maximum force applied when the pellet breaks is measured. The average value of 20 measurements is called the "dry compressive strength" (DCS).

[0174] Table 2: Amounts of binder and minerals in each agglomerate, and measurements of the physical properties of said agglomerates

[0175]

[0176] The application requirements for cold agglomeration require the dry hardness of the agglomerates to be greater than 250 kg so that manufacturers can directly add these agglomerates to furnaces with extremely high temperatures (blast furnaces and electric furnaces).

[0177] Table 2 shows that the agglomerates of Examples C1 to C4 using the binder composition according to the present invention are better compacted and have higher compressive resistance than the agglomerates of CEx 1 to CEx 5 in the comparative tests.

[0178] For manufacturers, effective compaction provides very important surface conditions for the agglomerates because the elements (cells) of the compaction wheel will not be blocked by fresh, uncompacted materials. In addition, good compaction can avoid the appearance of granular and / or non-smooth surfaces, which will lead to an increase in the abrasion index, thereby reducing the marketable size of the pellets and increasing the amount of dust in the furnace and during handling. The compressive resistance and plasticity of the agglomerates can avoid breakage, thereby reducing the drop index.

[0179] Compared with the tests of the comparative binder compositions CEx 1 to CEx 5, the dry compressive strength of the tests of the agglomerate compositions C1 to C4 according to the present invention has been improved. This parameter is crucial for manufacturers because it enables an understanding of the behavior of the agglomerates in extremely high-temperature furnaces: an increased dry compressive strength will prevent the agglomerates from breaking in the columns of blast furnaces and / or electric furnaces, thereby preventing a decrease in productivity due to the presence of an excessive fine powder content.

[0180] The number of drops of the agglomerates is also very important for the application of cold agglomeration to avoid breakage of the agglomerates before they are completely dry, which will lead to an increase in fine particles and a decrease in the dry strength of the agglomerates.

[0181] In contrast, binder compositions C1, C2, and C3 enable the attainment of the values required for cold agglomeration applications. In addition, it has also been observed that the selection of the molecular weights of polymers P1 and P2 is crucial for obtaining good physical properties. The binder composition according to the present invention can exhibit its effectiveness even at lower dosages, which is important for manufacturers because it can reduce the logistics and production costs of the agglomerates prepared by the cold agglomeration method.

[0182] Tests on the comparative adhesive compositions CEx 1 to CEx 5 have shown that it is necessary to use the adhesive compositions of the polymer compositions CP1 and P2 according to the invention.

Claims

1. A binding composition for manufacturing ore agglomerates, which comprises at least two different organic binders CP1 and P2 as follows: - A polymer composition CP1, which comprises a nonionic or anionic water-soluble synthetic polymer P1 with a weight-average molecular weight of 500,000 to 3 million Daltons, - A nonionic or anionic water-soluble synthetic polymer P2 with a weight-average molecular weight greater than 2 million Daltons, wherein both the polymer composition CP1 and the polymer P2 exist in the form of solid particles, wherein P1 is obtained by a gel polymerization method from at least one nonionic or anionic monomer in the presence of: - At least 1 wt% of a polymer P3, the polymer P3 containing at least one hydrophobic monomer, or - At least one hydrophobic monomer, the polymer composition CP1 contains 0.1 wt% to 20 wt% of at least one hydrophobic monomer, and the hydrophobic monomer is polymerized.

2. The adhesive composition according to claim 1, characterized in that, The binding composition contains at least 50 wt% of the polymer composition CP1.

3. The adhesive composition according to any one of the preceding claims, characterized in that, The polymer P1 contains at least 50 mol% of at least one nonionic monomer.

4. The adhesive composition according to any one of the preceding claims, characterized in that, The polymer P1 is nonionic.

5. The adhesive composition according to any one of claims 3 or 4, characterized in that The nonionic monomers of P1 are selected from acrylamide, methacrylamide, N-vinylformamide (NVF), N-vinylacetamide, N-vinylpyridine, N-vinylpyrrolidone (NVP), N-vinylimidazole, N-vinylsuccinimide, acryloylmorpholine (ACMO), acryloyl chloride, glycidyl methacrylate, glycerol methacrylate, diacetoneacrylamide, (meth)acrylic acid hydroxyalkyl ester, (meth)acrylic acid aminoalkyl ester, aminoalkyl (meth)acrylamide, (meth)acrylic acid thioalkyl ester, and mixtures thereof.

6. The adhesive composition according to any one of claims 3 to 5, characterized in that, At least one nonionic monomer of the polymer P1 is acrylamide.

7. The adhesive composition according to any one of the preceding claims, characterized in that, The polymer P1 is a copolymer of acrylamide and sodium acrylate.

8. The adhesive composition according to any one of the preceding claims, characterized in that, Polymer P1 contains at least one hydrophobic monomer selected from: haloalkyl derivatives of methacrylamidodimethylaminopropyl containing a C8-C 16 alkyl chain, ethoxylated behenyl methacrylate, diethylacrylamide, N-tert-butylacrylamide, and mixtures thereof.

9. The adhesive composition according to any one of the preceding claims, characterized in that, The polymer P3 contains 10 to 90 wt% of at least one hydrophobic monomer.

10. The adhesive composition according to any one of the preceding claims, characterized in that, The polymer P3 is a terpolymer of diethylacrylamide, N-tert-butylacrylamide, and sodium 2-acrylamido-2-methylpropanesulfonate.

11. The adhesive composition according to any one of the preceding claims, 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 ester, phosphonate ester, sulfate ester, sulfonate ester, xanthate ester, trithiocarbonate, dithiocarbamate, and dithioester.

12. The adhesive composition according to any one of the preceding claims, characterized in that, The polymer P3 does not contain carbon-carbon double bonds.

13. The adhesive composition according to any one of the preceding claims, characterized in that, The polymer P2 is a copolymer containing 5 to 100 mol% of sodium acrylate.

14. The adhesive composition according to any one of the preceding claims, characterized in that, The weight-average molecular weight of the polymer P2 is greater than that of the polymer P1.

15. An ore agglomerate, which contains 2,000 to 50,000 ppm of the binding composition according to any one of the preceding claims, based on the weight of the ore agglomerate.

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