METHOD FOR MANUFACTURING AN IRON MINERAL ENRICHED CONCENTRATE FROM AN ORE, AND USE OF A COMPOUND

Abstract

The invention relates to a method for manufacturing an iron mineral-enriched concentrate from an ore, containing an iron mineral and silicate, by reverse flotation, wherein the method comprises the step of (c) adding a compound of formula (i) wherein r1 is a linear c17 alkenyl, a linear c17 alkyl or a linear c15 alkyl, or a salt of a protonated compound of formula (i) and an anion, to an aqueous pulp prepared from the ore and, optionally, one or more flotation aids to obtain an aqueous mixture. For example, a mixture of compounds of formula (i) obtained by the reaction of fatty acids from soybean oil with n,n'-dimethylpropane-1,3-diamine is employed.

Description

METHOD FOR MANUFACTURING AN IRON MINERAL ENRICHED CONCENTRATE FROM AN ORE, AND USE OF A COMPOUND

[001] The present invention relates to a method for manufacturing an iron mineral-enriched concentrate from an ore containing an iron mineral and silicate, by reverse flotation using an amidoamine derivative. A further embodiment is the use of the amidoamine derivative as a flotation collector.

[002] A typical iron ore beneficiation process requires a flotation stage to remove silica (SiO2) from the valuable iron ore, for example, oxides such as hematite or magnetite, and thus obtain a high-grade iron ore concentrate. A high-grade iron ore concentrate allows for the production of high-quality steel. The removal of SiO2 from different ores by froth flotation in combination with hydrophobic amines is a well-known process. Negatively charged silicate particles can be hydrophobized using suitable amines. The injection of air into a flotation cell leads to the formation of hydrophobic gas bubbles, which can carry the hydrophobized silicate particles to the top of the flotation cell. The foam formed, which can be stabilized by a suitable chemical acting as a foam regulator, contains the hydrophobized silicate particles.Finally, the foam will be removed from the top and the enriched mineral will be left at the bottom of the flotation cell.

[003] US 2014-048454 refers to fatty starch amine collectors for the flotation beneficiation of aqueous ore suspensions, the use of said fatty starch amine collectors in flotation processes for ore beneficiation, more particularly in reverse flotation processes for the beneficiation of silicate-containing ore. In its examples, the following starch amine collectors are employed for a Petition 870210113640, dated 07 / 12 / 2021, page 12 / 44 / 24 reverse flotation of calcium carbonate at a neutral pH: rapeseed oil, N-(3(dimethylaminopropyl)amide (CAS No. 85408-42-0); tallow oil, N-(3(dimethylaminopropyl)amide (CAS No. 68650-79-3) and fish oil, N-(3(dimethylaminopropyl)amide (CAS No. 97552-95-9).

[004] US 2014-048453 refers to fatty alkoxylated polyamine collectors for the flotation beneficiation of aqueous ore suspensions, the use of said fatty alkoxylated polyamine collectors in flotation processes for ore beneficiation, more particularly in reverse flotation processes for the beneficiation of silicate-containing ores. In its examples, the following amidoamine collector is employed for reverse flotation of calcium carbonate at a neutral pH: rapeseed oil, N-(3-(dimethylaminopropyl)amide (CAS No. 85408-42-0).

[005] US 2014-144290 refers to collector compositions and methods for manufacturing and using them. The collector may include one or more etheramines and one or more amidoamines. A liquid suspension or paste comprising one or more particulates may be contacted with the collector to produce a treated mixture. A product may be recovered from the treated mixture that includes a purified liquid having a reduced concentration of particulates relative to the treated mixture, a purified particulate product having a reduced concentration of liquid relative to the treated mixture, or both. In their examples, the reverse flotation of an iron ore at a pH of 10.5 with SiO2 removal through frothing is shown inter alia with tallow fatty acid 1,3-diamine pentane amide or tallow fatty acid diethylenetriamine amide.

[006] US 2015-0096925 refers to collector compositions and methods for manufacturing and using them to purify one or more crude materials. The collector composition may include one or more amidoamines having the formula as represented below. Petition 870210113640, dated 07 / 12 / 2021, page 13 / 44 / 24 and one or more amines having the formula R6-NH2, wherein the weight ratio of the amidoamine to the amine may be from about 99:1 to about 1:99. In your example 1, a coconut fatty acid diethylenetriamine amidoamine neutralized with glacial acetic acid is used in a reverse flotation of a phosphate ore for silica removal at a neutral pH. In your example 2, a coconut fatty oil diethylenetriamine amidoamine neutralized with glacial acetic acid is used in a reverse flotation of a phosphate ore for silica removal at a neutral pH. In your example 3, a tallow fatty acid diethylenetriamine neutralized with glacial acetic acid is used for a reverse flotation of a phosphate ore for silica removal at a neutral pH. Other amidoamines employed similarly are lauric acid diethylenetriamine amidoamine and a rosin tetraethylenepentamine amidoamine.Some examples also come from a combination of an amidoamine with an amine, such as an etheramine composed of 95% by weight of 3-(8-methylnonoxy)propan-1-amine and 3% by weight of 8-methylnonan-1-ol, such as cocoamine or dodecylamine.

[007] There is still a need for improved methods in the reverse flotation of ores containing iron ore and silicate. Primarily, the quality of the ores has been decreasing. With a higher SiO2 content in the ore, the selective removal of silicate is more difficult than in the past with ores of lower SiO2 content. On the one hand, the loss of iron ore in the flotation process must be avoided, i.e., high recovery, and on the other hand, the SiO2 content must be reduced in a concentrate enriched in iron ore content to a low level, i.e., selectivity. Especially for direct reduction processes using the concentrate, a low SiO2 content is desirable. Typically, a mine as a processing site of Petition 870210113640, dated 07 / 12 / 2021, page 14 / 44 / 24, establishes that the ore will define a maximum level of residual SiO2 content that is allowed to remain in the concentrate at the end of the flotation process. This could be, for example, 2.5% by weight, especially 2.0% by weight. The goal is generally to achieve at least this maximum silica level without significantly losing any iron mineral content. Improved recovery combined with comparable or better selectivity reduces iron mineral losses in the tailings and leads to economic benefits.

[008] It is an object of the present invention to provide a method for manufacturing an iron mineral-rich concentrate with a high recovery of iron mineral from the applied ore and a low SiO2 content of the applied ore. Furthermore, it is attractive if a collector employed allows for reducing or even eliminating the need for a specific flotation aid. At the same time, it is an advantage if a material applied in the method can be economically manufactured in a chemically relatively pure and therefore homogeneous form, for example, because fewer side reactions can occur. A chemically relatively pure material offers, through combination with other materials, particularly other co-collectors, a precise fit for a specific ore.

[009] The objective is achieved, according to the invention, by a method for manufacturing an iron mineral-enriched concentrate from an ore containing an iron mineral and silicate, by reverse flotation, wherein the method comprises the step for (c) adding a compound of formula I (I) wherein R1 is a C17 linear alkenyl, a C17 linear alkyl or a C15 linear alkyl, or a salt of a protonated compound of formula I and an anion, to an aqueous pulp prepared from the ore and, optionally, Petition 870210113640, dated 07 / 12 / 2021, p. 15 / 44 / 24 one or more flotation aids to obtain an aqueous mixture.

[0010] Preferably, the method for manufacturing an iron mineral-enriched concentrate from an ore containing an iron mineral and silicate comprises the steps for (a) supplying the ore containing an iron mineral and silicate, (b) preparing an aqueous slurry from the supplied ore by adding water and, optionally, one or more flotation aids, (c) adding a compound of formula I (I) wherein R1 is a linear C17 alkenyl, a linear C17 alkyl or a linear C15 alkyl, or a salt of a protonated compound of formula I and an anion, to the prepared aqueous pulp of the ore and, optionally, one or more flotation aids to obtain an aqueous mixture, (d) aerating the aqueous mixture in a flotation cell to generate a foam, which is enriched in silicate content, and removing the foam generated from the flotation cell, (e) obtaining from the flotation cell the concentrate enriched in iron mineral content.

[0011] Steps (a), (b), (c), (d) and (e) describe reverse flotation in more detail.

[0012] The ore, which contains an iron and silicate mineral (SiO2), is, for example, from a magmatic deposit or a sedimentary deposit. Step (a) of ore provisioning includes, for example, also crushing or grinding, respectively, grinding the ore. In the case of an ore from a magmatic deposit, the step for ore provisioning includes, for example, also crushing the ore and Petition 870210113640, dated 07 / 12 / 2021, page 16 / 44 / 24 a crushing, respectively, grinding of the ore. In the case of an ore from a sedimentary deposit, the ore provisioning step comprises, for example, ore crushing, particularly ore crushing and wet crushing of the ore. Preferably, the ore provisioning step (a) results in ore particles that have a particle size allowing 60% to 100% by weight of the particles based on the total weight of the particles to pass through a 100 μm steel mesh sieve measured by standard dry sieving.

[0013] The ore contains for example 20% to 80% by weight of silicate based on the weight of the ore, particularly 25% to 75% by weight, very particularly 30% to 55% by weight and especially 30% to 40% by weight.

[0014] Preferably, the iron ore consists of 90% to 100% by weight of iron oxide based on all the iron minerals in the ore. Most preferably, the iron ore consists of at least 97% to 100% by weight of iron oxide, particularly preferably 99% to 100%. Typical iron oxides are hematite (Fe2O3 with 69.9% by weight iron content), magnetite (Fe3O4 with 72.4% by weight iron content) or a mixture of both. The weight of the iron content is similar to the weight content of Fe atoms.

[0015] A typical ore comprises between 40% and 70% by weight of hematite and 30% and 50% by weight of silica, particularly 45% to 65% by weight of hematite and 30% to 45% by weight of silica.

[0016] Preferred is an ore comprising iron ore, wherein more than 50% by weight of the iron ore comprised is an iron oxide, which is hematite. Much more preferably, more than 70% to 100% is an iron oxide, which is hematite.

[0017] The compound of formula I acts in the method as a collector for foam flotation.

[0018] The anion is the deprotonated form of an acid A(-H)p, in which Petition 870210113640, dated 07 / 12 / 2021, p. 17 / 44 / 24 H represents an acidic proton and p₀ the number of acidic protons of the acid A(H)p. Depending on the acid strength of the acid A(-H)p, some acidic protons of the acid A(-H)p may not be deprotonated in a salt with a compound of formula I.

[0019] A salt of a protonated compound of formula I and the anion is also expressed by the formula I-t1-1+ + (aY-)i / y(I-t1-1+), where A represents the anion, y is an integer that is at least 1, and y represents the negative charge of the anion. y is not greater than p, which is the number of acidic protons of the acid A(-H)p. An anion that is a deprotonated acid A(-H)p is preferred, where p is 1, 2, or 3, and y is 1 for p = 1, y is 1 or 2 for p = 2, and y is 1, 2, or 3 for p = 3.

[0020] The anion is, for example, C1-C18 carboxylate, fluoride, chloride, bromide, iodide, sulfonate, hydrogen sulfate, sulfate, dihydrogen phosphate, hydrogen phosphate, phosphate, nitrate, hydrofluorosilicate or fluorosilicate. The C1-C18 carboxylate is, for example, an aliphatic or olefinic carboxylate, preferably an aliphatic C1-C13 carboxylate, very preferably an aliphatic C1-C6 carboxylate, and especially formate, acetate or propionate. The preferred ones are C1-C18 carboxylate, fluoride, chloride, sulfonate, hydrogen sulfate, sulfate, dihydrogen phosphate, hydrogen phosphate, phosphate or nitrate. Very preferred is the aliphatic or olefinic C1-C18 carboxylate, particularly preferred is formate, acetate or propionate.

[0021] A method is preferred in which the anion is a C1-C18 carboxylate, fluoride, chloride, bromide, iodide, sulfonate, hydrogen sulfate, sulfate, dihydrogen phosphate, hydrogen phosphate, phosphate, nitrate, hydrofluorosilicate or fluorosilicate.

[0022] A condensation product of N',N'-dimethylpropane-1,3 Petition 870210113640, dated 07 / 12 / 2021, page 18 / 44 / 24. A condensation product of N',N'-dimethylpropane-1,3-diamine with rapeseed oil is known under CAS No. 85408-42-0. A condensation product of N',N'-dimethylpropane-1,3-diamine with tallow oil is known under CAS No. 68650-79-3. A condensation product of N',N'-dimethylpropane-1,3-diamine with fish oil is known under CAS No. 97552-95-9. A condensation product of N',N'-dimethylpropane-1,3-diamine (alternative name: 3-(dimethylamino)propylamine) with soybean oil is known under CAS No. 68188-30-7 and named in the CAS registry as amides, soy, N-[3-(dimethylamino)propyl.Soybean oil has distribution ranges of individual fatty acids, which is described in the literature, for example, as containing as main components about 8 to 14 mol% of palmitic acid, about 1 to 6 mol% of stearic acid, about 17 to 30 mol% of oleic acid, about 48 to 59 mol% of linoleic acid and about 4 to 11 mol% of linolenic acid - all based on the total molar amount of fatty acids, which is 100 mol%. For example, a specific distribution of the main fatty acid components of soybean oil is described in the literature cited as approximately 10 mol% palmitic acid, approximately 5 mol% stearic acid, approximately 21 mol% oleic acid, approximately 53 mol% linoleic acid, and approximately 8 mol% linolenic acid – based on the total molar quantity of fatty acids, which is 100 mol%.The meaning of "around" in the two previous sentences also refers to the small differences when considering % by weight versus % by mole. The molecular weight of the main components is not the same, but it is also not very different; therefore, as a first approximation, % by weight can be taken as % by mole and vice versa. The fatty acids from soybean oil can be distilled, which can lead to changes compared to the fatty acid distribution before distillation. Amoidoamine obtained from a condensation of N',N'-dimethylpropane-1,3-diamine with palmitic acid is known under CAS No. 39669-97-1, a chloride salt of protonated amidoamine under CAS No. 151190-60-2, a. Petition 870210113640, dated 07 / 12 / 2021, page 19 / 44 / 24 palmitate salt of protonated amidoamine under CAS No. 220820-88-2, an acetate salt of protonated amidoamine under CAS No. 83763-68-2. The amidoamine product obtained from a condensation of N',N'-dimethylpropane-1,3-diamine with stearic acid is known under CAS No. 7651-02-7, a chloride salt of protonated amidoamine under CAS No. 83607-13-0, a stearate acid salt of protonated amidoamine under CAS No. 127358-77-4, an acetate salt of protonated amidoamine under CAS No. 13282-70-7. The amidoamine product obtained from a condensation of N',N'-dimethylpropane-1,3-diamine with oleic acid is known under CAS No. 109-28-4, a bromide salt of protonated amidoamine under CAS No. 76959-11-0, an oleate salt of protonated amidoamine under CAS No. 70715-14-9, an acetate salt of protonated amidoamine under CAS No. 13282-68-3, a sulfate salt of two of the protonated amidoamines under CAS No. 1638206-65-1.The amidoamine product obtained from a condensation of N',N'-dimethylpropane-1,3-diamine with linoleic acid is known under CAS No. 81613-56-1, a linoleate salt of protonated amidoamine under CAS No. 651294-42-7, a 2-hydroxypropionate salt of protonated amidoamine under CAS No. 187939-51-1. The amidoamine product obtained from a condensation of N',N'-dimethylpropane-1,3-diamine with linolenic acid is known under CAS No. 122955-03-7.

[0023] A compound of formula I, where R1 is a linear C17 alkenyl, which is (8Z)-heptadec-8-enyl, is represented below. One chemical name is (Z)-N-[3-(dimethylamino)propyl]octadec9-enamide.

[0024] A compound of formula I, wherein R1 is a linear C17 alkenyl, which is (8Z,11Z)-heptadec-8,11-dienyl, is represented below. Petition 870210113640, dated 07 / 12 / 2021, page 20 / 44 / 24 and a chemical name is (9Z,12Z)-N-[3(dimethylamino)propyl]octadeca-9,12-dienamide.

[0025] A compound of formula I, where R1 is a linear C17 alkenyl, which is (8Z,11Z,14Z)-heptadec-8,11,14-trienyl, is represented below. One chemical name is (9Z,12Z,15Z)-N-[3(dimethylamino)propyl]octadeca-9,12,15-trienamide.

[0026] A compound of formula I, where R1 is a linear C17 alkyl, is represented below. THE One chemical name is N-[3(dimethylamino)propyl]octadecanamide.

[0027] A compound of formula I, where R1 is a linear C15 alkyl, is represented below. THE One chemical name is N-[3(dimethylamino)propyl]hexadecanamide.

[0028] Preferred is a method in which linear C17 alkenyl is (8Z)heptadec-8-enyl, (8Z,11Z)-heptadec-8,11-dienyl or (8Z,11Z,14Z)-heptadec8,11,14-trienyl. Petition 870210113640, dated 07 / 12 / 2021, p. 21 / 44 / 24

[0029] Preferred is a method in which, in step c), a compound of formula I is added, in which R1 is linear C17 alkenyl.

[0030] A preferred method is in which, in step c), a mixture comprising different compounds of formula I or salts of the different protonated compounds of formula I and anions is added.

[0031] A method is preferred, wherein in step c) a mixture comprising different compounds of formula I or salts of different protonated compounds of formula I and anions are added, and the mixture comprises (i) 50 mol% to 100 mol% of a compound of formula I, wherein R1 is linear C17 alkenyl, or a salt of the protonated compound of formula I and an anion, wherein the amount of (i) is based on all compounds of formula I and salts of protonated compounds of formula I, which is 100 mol%. Much preferred is an amount of 60 mol% to 100 mol%, particularly preferred is an amount of 70 mol% to 100 mol%, and especially preferred is an amount of 72 mol% to 95 mol%.

[0032] A preferred method is wherein in step c) a mixture comprising different compounds of formula I or salts of different protonated compounds of formula I and anions are added, and the mixture comprises (i) 50 mol% to 98 mol% of a compound of formula I, wherein R1 is C17 linear alkenyl, or a salt of the protonated compound of formula I and an anion, (ii) 1 mol% to 25 mol% of a compound of formula I, wherein R1 is C15 linear alkyl, or a salt of the protonated compound of formula I and an anion, and (iii) 1 mol% to 25 mol% of a compound of formula I, wherein R1 is C17 linear alkyl, or a salt of the protonated compound of formula I. Petition 870210113640, dated 07 / 12 / 2021, p. 22 / 44 / 24 and an anion, where the total amount of (i), (ii) and (iii) is 100% by mole based on all compounds of formula I and salts of the protonated compounds of formula I.

[0033] A preferred method is wherein in step c) a mixture comprising different compounds of formula I or salts of different protonated compounds of formula I and anions are added, and the mixture comprises (i) 65 to 91 mol% of a compound of formula I, wherein R1 is C17 linear alkenyl, or a salt of the protonated compound of formula I and an anion, (ii) 8 to 22 mol% of a compound of formula I, wherein R1 is C15 linear alkyl, or a salt of the protonated compound of formula I and an anion, and (iii) 1 to 6 mol% of a compound of formula I, wherein R1 is C17 linear alkyl or a salt of the protonated compound of formula I and an anion, wherein the total amount of (i), (ii) and (iii) is 100 mol% based on all compounds of formula I and salts of protonated compounds of formula I.

[0034] A preferred method is wherein in step c) a mixture comprising different compounds of formula I or salts of different protonated compounds of formula I and anions are added, and the mixture comprises (i) 67 to 91 mol% of a compound of formula I, wherein R1 is linear C17 alkenyl, or a salt of the protonated compound of formula I and an anion (ii) 8 to 21 mol% of a compound of formula I, wherein R1 is linear C15 alkyl, or a salt of the protonated compound of formula I and an anion, and Petition 870210113640, dated 07 / 12 / 2021, p. 23 / 44 / 24 (iii) 2 to 6 mol% of a compound of formula I, wherein R1 is linear C17 alkyl or a salt of the protonated compound of formula I and an anion, wherein the total amount of (i), (ii) and (iii) is 100 mol% based on all compounds of formula I and salts of the protonated compounds of formula I.

[0035] A preferred method is one in which, in step c), a mixture comprising different compounds of formula I or salts of the different protonated compounds of formula I and anions are added, and for the total amount of compounds of formula I, wherein R1 is linear C17 alkenyl, the molar ratio of monounsaturated linear C17 alkenyl to polyunsaturated linear C17 alkenyl is from 0.5 to 0.83.

[0036] A method is preferred, in which at step c) a mixture comprising different compounds of formula I or salts of the different protonated compounds of formula I and anions is added and the mixture is obtained by condensing soybean oil fatty acids with N',N'-dimethylpropane-1,3-diamine under removal of water. Much preferably, the mixture is the reaction product obtained in example A-1.

[0037] In step c), adding a compound of formula I or adding a salt of the protonated compound of formula I are two options. In view of the total amount of chemicals added, adding a compound of formula I without an anion is more attractive to reduce the total amount of chemicals added. Particularly, if a desired pH value of the reverse flotation is between 8 and 12, very particularly between 9 and 12 and especially between 9 and 11.

[0038] Preferred is a method in which, in step c), a compound of formula I is added.

[0039] The compound of formula I is preferably added in a quantity of 10 g 500 g per tonne of ore. The calculation is based on dry ore. The quantity is most preferably Petition 870210113640, dated 07 / 12 / 2021, p. 24 / 44 / 24 of 30 ga 300 g per ton of ore, particularly preferably 40 ga 280 g per ton of ore, especially 70 ga 270 g per ton of ore and very especially 170 ga 260 g per ton of ore.

[0040] Preferred is a method in which the compound of formula I is added in an amount between 10 g and 500 g per tonne of ore.

[0041] Preferred is a method in which the compound of formula I is added in an amount between 30 g and 300 g per tonne of ore.

[0042] The pH value in steps (c) and (d) of the method is preferably adjusted with a pH regulator to a specific pH value, typically to a pH value between 8 and 12, particularly between 9 and 11. A pH regulator is typically a strong base, for example sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate. Preferably, the pH value of the aqueous pulp is between 8 and 12, particularly between 9 and 11. Preferably, step (c), i.e., adding the compound of formula to the aqueous pulp, occurs at a pH value between 8 and 12, particularly between 9 and 11. Preferably, the pH value of the aqueous mixture is between 8 and 12, particularly between 9 and 11. Preferably, step (d), i.e., aerating the aqueous mixture, occurs at a pH value between 8 and 12, particularly between 9 and 11. Preferably, (e), i.e., obtaining the concentrate enriched in iron mineral content, occurs at a pH value between 8 and 12, particularly between 9 and 11.Regulating the pH value ensures that the ore, especially the ore particles, exhibit the correct surface charge.

[0043] A method is preferred in which the pH value in step (c) is between 8 and 12.

[0044] A method is preferred in which the pH value in step (c) and in step (b) is between 8 and 12.

[0045] Preferred is a method, in which the pH value in step (c) and in Petition 870210113640, dated 07 / 12 / 2021, page 25 / 44 / 24 stage (d) is between 8 and 12.

[0046] A method is preferred in which the pH value in step (c), in step (b) and in step (d) is between 8 and 12.

[0047] A method is preferred in which the pH value in step (c), in step (b), in step (d) and in step (e) is between 8 and 12.

[0048] A flotation aid is, for example, a depressant, a foam regulator, a coco-collector or an extender oil.

[0049] A depressant helps prevent the flotation of an ore ingredient, which is undesirable for obtaining part of the foam, or generally supports the selectivity of the concentrate manufacturing method. A depressant is, for example, a hydrophilic polysaccharide, particularly a starch or sodium silicate. The starch is, for example, a native starch or a modified starch. A native starch is, for example, a starch from corn, wheat, oats, barley, rice, millet, potato, pea, tapioca, or cassava. The native starch is preferably pre-gelatinized, that is, heated to gelatinize the starch. A modified starch is a degraded starch, which has a reduced weighted average molecular weight compared to the original starch, a chemically modified starch, or a degraded and chemically modified starch. Starch degradation is, for example, possible by oxidation or treatment with acid, base, or enzymes.Degradation typically leads to an increased content of oligosaccharides or dextrins. A chemical modification is the functionalization of a starch by the covalent bonding of a chemical group to the starch. A chemically modified starch can be obtained, for example, by esterification or etherification of a starch. Esterification of an acid with a starch is, for example, carried out with an anhydride of the acid or a chloride of the acid. Etherification of a starch is, for example, possible with an organic reagent containing a reactive epoxide functionality. Preferred is a depressant agent, which is a native starch, particularly a pre-gelatinized starch. An agent. Petition 870210113640, dated 07 / 12 / 2021, p. 26 / 44 / 24: Depressant is preferably added in a quantity of 100 to 3000 g per ton of ore. The calculation is based on dry ore. The quantity is most preferably 300 g to 2200 g per ton of ore, particularly preferably 400 g to 1900 g per ton of ore, especially 500 g to 1700 g per ton of ore, and most especially 600 g to 1400 g per ton of ore.

[0050] A foam regulator helps improve the efficiency of the manufacturing method by interfering with foam generation. A property of foam is, for example, foam height, respectively, foam volume or foam stability, i.e., the time to collapse after stopping aeration. A foam regulator is, for example, pine oil, methylisobutyl carbinol, C6-C12 alcohol, particularly 2-ethylhexanol or hexanol, an alcoholic ester, particularly a mixture comprising 2,2,4-trimethyl-1,3-pentandiol-monoisobutyrate, terpineol, triethoxybutane, an alkoxylated alcohol, particularly an ethoxylated and / or propoxylated alcohol, polyethylene glycol or polypropylene glycol.

[0051] A cococollector is a surfactant compound that is different from a compound of formula I. A cococollector is, for example, cationic, non-ionic or anionic, preferably cationic or non-ionic and very preferably cationic. A cationic cococollector is, for example, C9-C18 alkylamine, 2-(C9-C18 alkylamino)ethyl-1-amine, N'-(C9-C18 alkyl)propane-1,3-diamine, 3-(C9-C18 alkoxy)propyl-1-amine, N'-(3-(C9-C18 alkoxy)propyl)propane-1,3-diamine. A non-ionic cococollector is, for example, a branched C9-C15 alkyl alcohol, or a branched and ethoxylated C9-C15 alkyl alcohol with 2 to 4 moles of ethylene oxide. In the case of a coco-collector as a flotation aid, the coco-collector can be added together with the compound of formula I. In this case, this part of step (b) occurs simultaneously with step (c).

[0052] It is still attractive, if the method does not require adding a Petition 870210113640, dated 07 / 12 / 2021, page 27 / 44 / 24 cocolector.

[0053] A preferred method is one in which an amine of formula R2NH2, wherein R2 is a C1-C24 alkyl, a phenyl, a benzyl, a C1-C24 alkenyl, a heterocyclyl, an unsubstituted aryl or an aryl substituted with one or more C1-C8 alkyl substituents, is contained in a weight ratio of less than 1 to 100, 100 being the weight amount of all compounds of formula I. Much preferred, the method is free from adding an amine of formula R2-NH2. Particularly preferred, the method is free from adding an amine of formula R2-NH2 or a salt of a protonated amine of formula R2-NH2 and an anion.

[0054] A method is preferred in which an etheramine is contained in a weight ratio of less than 20 to 100, with 100 being the weight amount of all compounds of formula I. Much preferred is a method in which an etheramine is contained in a weight ratio of less than 1 to 100, with 100 being the weight amount of all compounds of formula I. Particularly preferred is the method that is free from adding an etheramine. Especially preferred is the method that is free from adding an etheramine or a salt of a protonated etheramine and an anion. An etheramine is here understood to be a molecule comprising the structural element alkyl-O-alkylene-NH-..., for example, molecules described by alkyl-O-alkylene-NH2 or alkyl-O-alkylene-NH-alkylene-NH2.

[0055] An extender oil is, for example, kerosene.

[0056] A method is preferred in which, in step (b), one or more flotation aids are added and one of the flotation aids is a depressant, a foam regulator, a coco-collector or an extender oil.

[0057] A method is preferred in which one of the flotation aids added in step (b) is a depressant.

[0058] A method is preferred in which one of the flotation aids Petition 870210113640, dated 07 / 12 / 2021, page 28 / 44 / 24 added in step (b) is a depressant and one of the flotation aids is a cocolector, which is added in step (b) before step (c) or is added simultaneously with the compound of formula I.

[0059] The addition of corn starch, generally considered a depressant, is a common practice. It has been found that adding a compound of formula I as obtained in example A-1 provides better results in the absence of pregelatinized corn starch versus the presence of pregelatinized corn starch. Preferably, the method is free of the addition of pregelatinized corn starch, very preferably free of the addition of corn starch, particularly free of the addition of starch, and very particularly free of the addition of a hydrophilic polysaccharide.

[0060] Preferred is a method that is exempt from adding cornstarch.

[0061] In the method of manufacturing a concentrate, conventional reverse flotation plant equipment can be used. Preferably, the compound of formula I and, optionally, a flotation aid, which is a cocolector, is or are added to the aqueous pulp, which is already in the flotation cell, which is used to aerate the mixture in step (d).

[0062] After adding a compound of formula I to the aqueous pulp, the resulting aqueous mixture is preferably maintained, particularly under agitation, for a conditioning period before aerating the aqueous mixture. This allows the compound of formula I and optionally a flotation aid, which is a co-collector, to condition the ore, particularly the ore particles, in the aqueous mixture. The conditioning period lasts, for example, one minute or up to 10 or 15 minutes.

[0063] When aerating the aqueous mixture, air is typically injected into the base of the flotation cell. Air bubbles are formed and rise to the surface, generating foam on the surface. Air injection can be continued until no more bubbles are formed. Petition 870210113640, dated 07 / 12 / 2021, page 29 / 44 / 24 form more foam. This can last, for example, one minute or up to 15 or 20 minutes. The foam is removed.

[0064] To obtain concentrate enriched with iron mineral content, aeration is normally stopped. Concentrate enriched with iron mineral content normally sinks to the bottom of the flotation cell.

[0065] In some cases, it may be desirable to treat the iron mineral-enriched concentrate in a similar manner again. For example, steps (c) and (d) are repeated as step (dc) followed by step (dd) before step (e) is carried out.

[0066] The iron mineral-enriched concentrate preferably contains at least 60% by weight of Fe atoms based on the total weight of the iron mineral-enriched concentrate, most preferably at least 65% by weight. The weight of the Fe atoms is similar to the weight of the iron content. The iron mineral-enriched concentrate preferably contains less than 2.5% by weight of SiO2 based on the total weight of the iron mineral-enriched concentrate, most preferably less than 2.1% by weight and particularly preferably 2.0% or less than 1.9% by weight of SiO2. The iron mineral-enriched concentrate preferably contains at least 60% by weight of Fe atoms and less than 2.5% by weight of SiO2 based on the total weight of the iron mineral-enriched concentrate, most preferably at least 65% by weight of Fe atoms and less than 2.1% by weight of SiO2.

[0067] The preferences described above for the method of manufacturing a concentrate or for the added compound of formula I are described for the method. These preferences also apply to another embodiment of the invention.

[0068] An additional embodiment of the invention is the use of a Petition 870210113640, dated 07 / 12 / 2021, p. 30 / 44 / 24 composed of formula I (I) where R1 is a C17linear alkenyl, a C17linear alkyl or a C15linear alkyl, or a salt of a protonated compound of formula I and an anion, as a flotation collector for making an iron mineral-enriched concentrate from an ore containing an iron mineral and silicate, by reverse flotation.

[0069] Figures 1 to 4 are attached and described below.

[0070] Figure 1 shows an IR spectrum of the material obtained in example A-1. The x-axis shows the wavelength in cm-1 and the y-axis shows the transmission in percentage.

[0071] Figure 2 shows a 13C-NMR spectrum of the material obtained in example A-1 in CDCl3.

[0072] Figure 3 shows a 1H-NMR spectrum of the material obtained in example A-1 in CDCl3.

[0073] Figure 4 shows a 1H-NMR spectrum between about 0.7 ppm and about 5.6 ppm of the material obtained in example A-2 in CDCl3. Figure 4 is an enlarged extract of Figure 3.

[0074] The following examples better illustrate the invention without limiting it. Percentage values ​​are percentages by weight unless otherwise stated. A) collector employed A-1: Product of the reaction of N,N-dimethylpropane-1,3-diamine and soybean oil fatty acid (101) + - h2o (101) Petition 870210113640, dated 07 / 12 / 2021, p. 31 / 44 / 24

[0075] A stirred solution of distilled soybean oil fatty acid (416 g, 1.5 mol, RA1-C(= O)OH, with a fatty acid composition of 0.89% C12, 0.45% C14, 18.20% C16, 4.71% C18, 29.55% C18 monounsaturated, 43.19% C18 diunsaturated, 3.01% C18 triunsaturated) is heated to 40°C and N',N'-dimethylpropane-1,3-diamine (199 g, 1.95 mol; molar ratio of RA1-C(= O)OH to H2N-CH2-CH2-CH2-N(CH3)2 is 1 to 1.3) is added over 5 minutes. The addition causes an exothermic reaction due to the formation of a salt. After complete addition, the reaction mixture is automatically heated to 80°C and then slowly heated to 150°C over 1.5 hours. The mixture is refluxed at 150°C for 1 hour. After this step, the water is distilled. The reaction temperature is slowly raised to 180°C and maintained at this temperature for one hour. The acid value is measured by titration to identify the end of the reaction. After all the fatty acid has been consumed, the mixture is cooled to 50°C.The reaction product (101) is obtained as a yellowish-brown solid (91% yield, there are fatty acids remaining in the reaction product because some of the amine is lost with the distillation of water).

[0076] Content of unreacted fatty acids: 13 mg KOH / g of (101) measured by titration with KOH solution (0.05%) and phenolphthalein indicator. 13 mg formally corresponds to 65 mg of oleic acid per g of product.

[0077] FT-IR vmax (liquid film, obtained by heating and transforming into a liquid for measurement) main bands: 3292.2, 3083.6, 2926.3, 2855.7, 1648.8, 1559, 1462.7 cm-1

[0078] 13C-NMR (126 MHz, CDCL): 173.04 (C-6), 130.19 (double links), 130.03 (double links), 129.97 (double links), 129.74 (double links), 128.05 (double links), 127.92 (double links), 58.60 (C-2), 45.39 (C-10, C-11), 39.19 (C-4), 36.95 (C-7), 31.93, 31.91, 31.53, 29.78, 29.75, 29.70, 29.67, 29.65, 29.53, 29.43, 29.36, 29.33, 29,18, 27,22 (C-21, C Petition 870210113640, dated 07 / 12 / 2021, p. 32 / 44 / 24 24), 26,28 (C-3), 25,79 (C-34), 25,64, 22,69, 22,58, 14,11 (C-13). The unassigned carbon signs belong to the aliphatic fatty acid chains.

[0079] 1H-NMR (500 MHz, CDCk): 7.05 (s, 1H, NH), 5.45 - 5.24 (m, 2H, H-double bonds), 3.39 - 3.27 (m, 2H, H-4), 2.86 - 2.70 (m, 1H, H-34), 2.37 (t, J (H-3) = 6.4 Hz, 2H, H-2,), 2.21 (s, 6H, H-10, H-11), 2.14 (t, 2H, H7), 2.09 - 1.89 (m, 3H, H-21, H-24), 1.63 (q, J (H-2, H -4) = 6.2 Hz, H, H3), 1.60 (s wide, 2H, H-8) 1.50 - 1.08 (m, 17H, aliphatic protons), 1.01 - 0.79 (m, 3H, H13). The intensity ratio between the CH3 group of fatty acids (0.9 ppm) and the double bond hydrogen signals (5.4 ppm) is approximately 3:2.2. Consequently, there is more than one double bond on average per fatty acid unit.

[0080] The FT-IR spectrum of the reaction product (101) is shown in Figure 1. The 13C-NMR spectrum of the reaction product (101) is shown in Figure 2. The 1H-NMR spectrum is shown in Figure 3 and an enlarged extract is shown in Figure 4. A-2: 3-iso-nonoxypropan-1-amine (etheramine) (201) [comparative] B) Flotation

[0081] 750 g of ore (based on hematite, 43.58% Fe, 37.64% The ore (SiO2; 0.52% Al2O3) is placed in a 1.5 L flotation cell in a flotation machine. 400 mL of distilled water is added at room temperature (~21°C), resulting in the formation of a 65% solids pulp. This pulp is conditioned with pre-gelatinized corn starch (665 g / t calculated as dry starch per dry ore) for 5 minutes or without starch, respectively, at an agitation of 1000 rpm as established in Table B-1. After 5 minutes, the pH is adjusted to 10.2 with an aqueous solution of sodium hydroxide (5%). A collector is added as established in Table B-1 (calculated as collector substance per dry ore) in the form of an aqueous solution (1% collector substance) prepared in distilled water. The pH is adjusted to 10.2 Petition 870210113640, dated 07 / 12 / 2021, page 33 / 44 / 24 with an aqueous solution of sodium hydroxide (5%). The pulp is subsequently conditioned for 1 minute under the same agitation. After conditioning, the vessel volume is filled with distilled water to 2 cm below the rim level under agitation at 1000 rpm. The pH is corrected to 10.2 again before the start of flotation with an aqueous solution of sodium hydroxide (5%). Flotation is initiated by opening the aeration. The flotation cell is self-aerating and does not have an external air supply. The airflow is not measured. The foam is collected by regular manual scraping in a 2 l tray until completely exhausted. The foam containing solids collected in the tray and the remaining cellular fraction are separately dehydrated, dried, weighed, and the Fe and SiO2 content of both are analyzed by XRF measurement on a molten lithium borate-based bead. The results are listed in Table B-1. Table B-1: Example No. Collector Quantity of collector [g / t] Quantity of pregelatinized corn starch [g / t] Degree of concentration of Fe c) [percentage by weight of Fe atom] Degree of concentration of SiO2 d) [percentage by weight of SiO2] Fe recovery e) [percentage by weight of Fe atom] B-1-1a) (201) 156 665 65.2 2.8 70.4 B-1-2a) (201) 156 - 36.7 35.5 7.17 B-1-3 b) (101) 400 665 65.3 2.6 66.2 B-1-4b) (101) 250 - 67.3 1.8 69.5 Support notes: a) comparative b) according to the invention c) Degree of concentration of Fe means the content of Fe atoms in the cellular fraction. d) Degree of SiO2 concentration means the SiO2 content in the cellular fraction. (e) Recovery is the ratio between the total amount of Fe atoms contained in the cell fraction and the total amount of Fe atoms contained in the ore used as starting material. The results in Table B-1 show that a degree of Petition 870210113640, dated 07 / 12 / 2021, page 34 / 44 / 24. A concentrated, targeted solution with a lower SiO2 content (2.6%) in example B-1-3 is achieved compared to example B-1-1 with its SiO2 content (2.8%), and > 65% Fe is found in both examples. Example B-1-2 shows that the comparative etheramine does not work without pre-gelatinized starch, while example B-1-4 shows even better results without pre-gelatinized starch compared to example B-1-3 regarding SiO2 content (1.8%) and Fe (67.3%).

Claims

CLAIMS 1. Method for manufacturing an iron mineral-enriched concentrate from an ore containing an iron mineral and silicate, by reverse flotation, wherein the method comprises the steps for (a) providing the ore containing an iron mineral and silicate, (b) preparing from the provided ore by adding water and, optionally, one or more flotation aids, an aqueous slurry, and wherein the method is characterized in step (C), in which (c) a compound of formula I (I) where R1 is a linear C17 alkenyl, a linear C17 alkyl or a linear C15 alkyl, or a salt of a protonated compound of formula I and an anion, is added to an aqueous slurry prepared from the ore and, optionally, one or more flotation aids to obtain an aqueous mixture.

2. Method according to claim 1, characterized in that the method further comprises the steps for (d) aerating the aqueous mixture obtained in claim 1 in a flotation cell to generate a foam, which is enriched in silicate content, and removing the generated foam from the flotation cell, and (e) obtaining, from the flotation cell, the concentrate enriched in iron mineral content.

3. Method according to claim 1 or 2, characterized in that linear C17 alkenyl is (8Z)-heptadec-8-enyl, (8Z,11Z)heptadec-8,11-dienyl or (8Z,11Z,14Z)-heptadec-8,11,14-trienyl.

4. Method according to any of the preceding claims, characterized in that in step c) a mixture comprising different compounds of formula I or salts of the different protonated compounds of formula I and anions is added.

5. Method according to claim 4, characterized in that the mixture comprises (i) 50 mol% to 98 mol% of a compound of formula I, wherein R1 is linear C17 alkenyl, or a salt of the protonated compound of formula I and an anion, (ii) 1 mol% to 25 mol% of a compound of formula I, wherein R1 is linear C15 alkyl, or a salt of the protonated compound of formula I and an anion, and (iii) 1 mol% to 25 mol% of a compound of formula I, wherein R1 is linear C17 alkyl, or a salt of the protonated compound of formula I and an anion, wherein the total amount of (i), (ii) and (iii) is 100 mol% based on all compounds of formula I or salts of the different protonated compounds of formula I and anions.

6. Method according to claim 4 or 5, characterized in that the mixture comprises (i) 65 to 91 mol% of a compound of formula I, wherein R1 is linear C17 alkenyl, (ii) 8 to 22 mol% of a compound of formula I, wherein R1 is linear C15 alkyl, and (iii) 1 to 6 mol% of a compound of formula I, wherein R1 is linear C17 alkyl, wherein the total amount of (i), (ii) and (iii) is 100 mol% based on all compounds of formula I or salts of the different protonated compounds of formula I and anions.

7. Method according to any of claims 4 to Petition 870260010023, dated 02 / 02 / 2026, page 13 / 19 3 / 4 6, characterized in that in the total amount of compounds of formula I, where R1 is linear C17 alkenyl, the molar ratio between monounsaturated linear C17 alkenyl to polyunsaturated linear C17 alkenyl is from 0.5 to 0.

83.

8. Method according to any of the preceding claims, characterized in that in step c) a mixture comprising different compounds of formula I or salts of the different protonated compounds of formula I and anions is added and the mixture is obtained by condensation of soybean oil fatty acids with N',N'-dimethylpropane-1,3-diamine under removal of water.

9. A method according to any of the preceding claims, characterized in that the anion is a C1-C18 carboxylate, fluoride, chloride, bromide, iodide, sulfonate, hydrogen sulfate, sulfate, dihydrogen phosphate, hydrogen phosphate, phosphate, nitrate, hydrofluorosilicate, or fluorosilicate.

10. A method according to any of the preceding claims, characterized in that the compound of formula I is added in an amount between 10 g and 500 g per ton of ore.

11. Method according to any of the preceding claims, characterized in that the pH value in step (c) is between 8 and 12.

12. Method according to any of the preceding claims, characterized in that in step (b) one or more flotation aids are added and one of the flotation aids is a depressant, a foam regulator, a coco-collector or an extender oil.

13. A method according to any of the preceding claims, characterized in that it is free from the addition of corn starch.

14. Use of a compound of formula I as defined in claim 1 or a salt of a protonated compound of formula I and an anion Petition 870260010023, dated 02 / 02 / 2026, page 14 / 19 4 / 4 as defined in claim 1, characterized in that it is used as a flotation collector for manufacturing an iron mineral-enriched concentrate from an ore containing an iron mineral and silicate, by adding it to an aqueous slurry prepared from a provided ore, containing added water and, optionally, one or more flotation aids in reverse flotation.

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