ESTERQUATS FOR THE FLOTATION OF NON-SULFURFED MINERALS AND ORES AND THE FLOTATION PROCESS

Description

[0001] The present invention relates to novel ester quats obtainable by reacting di- or trialkanolamines with fatty acids and polycarboxylic acids and quaternizing the esters thus obtained, optionally after alkoxylation. The invention further relates to a process for the foam flotation of non-sulfide minerals and ores, and in particular the use of the ester quats as a collector in a foam flotation process.

[0002] Flotation is a separation technique commonly used in mineral processing. It separates the raw ores into valuable material and gangue. Non-sulfide minerals and ores within the scope of the present invention include, for example, calcite, apatite, fluorite, scheelite, barite, iron oxides and other metal oxides, such as the oxides of titanium and zirconium, as well as certain silicates and aluminosilicates.

[0003] In flotation-based processing, the mineral or ore is first crushed by dry or, preferably, wet grinding and suspended in water. The collector, often in conjunction with foamers and other auxiliary reagents such as pressure boosters or activators, is then added to the ore-water mixture to separate the valuable material from the unwanted gangue of the ore. After a specific reaction time of the reagents (conditioning), air is introduced into the suspension. Due to the cell geometry, the air is finely dispersed and generates a foam on the surface of the flotation cell.

[0004] The collector makes the surface of the minerals hydrophobic, causing them to adhere to the air bubbles when the air bubble and particles come into contact. The collectors selectively hydrophobize the minerals, so that in the case of direct flotation, the valuable minerals rise to the surface, and in the case of reverse flotation, the gangue particles collect on the surface. The solids-containing foam is scraped off the cell surface and transported further. The goal of flotation is to separate the valuable material of the minerals and ores from the gangue with the highest possible yield, while simultaneously achieving a high concentration of the valuable mineral.

[0005] In non-sulfide flotation, such as reverse calcite flotation, anionic, cationic, and ampholytic surfactants are primarily used as collectors. These surfactants often also have a foaming effect, eliminating the need for a separate foaming agent. Calcite is an important filler in the paper industry because it allows for the adjustment of the paper's whiteness and transparency. However, calcite minerals are often accompanied by silicates, iron oxides, and other constituents, which negatively impact purity and must therefore be removed.

[0006] WO-2008 / 089906 is considered to be the state of the art, in which the use of polymeric ester quats as collectors for silicates and magnesium salts in non-sulfide flotation is described as particularly effective.

[0007] DE-102008056338 teaches the use of a compound of A) at least one quaternary ammonium compound containing at least one organic residue with 1 to 36 carbon atoms bonded to the ammonium nitrogen atom, optionally containing heteroatoms, and B) at least one aminal lkoxy ester of formula (1) or a salt thereof wherein A, B independently of each other a C 2 to C 5 alkylene residue R 1< a C 8 to C 24 alkyl residue or -alkenyl residue R 2< , R 3< , R 4< independently of each other H or a C 8 to C 24 acyl residue, with the proviso that at least one of the residues R 2< , R 3< or R 4< represents a C 8 to C 24 acyl residue x, y, z independently of each other an integer from 0 to 50 with the proviso that x + y + z is an integer from 1 to 100, signify, in quantities of 10 to 5000 g / tonne ore as collector in silicate flotation.

[0008] The object of the present invention is to provide an improved collector for various flotation processes, with which it is possible to achieve better selectivity with the same amount of collector while maintaining a consistently high yield. In particular, the collector should be suitable for reverse calcite flotation and produce purer calcite with the lowest possible loss.

[0009] Surprisingly, it was found that ester quats, obtained by reacting di- or trialkanolamines with fatty acids and polycarboxylic acids and quaternizing the resulting esters—optionally after alkoxylation—in a known manner, represent an improved collector for various flotation processes. The new ester quats have proven surprisingly effective, particularly in reverse calcite flotation, and also exhibit very good biodegradability, which is of particular importance to calcite producers.

[0010] The present invention therefore relates to ester quats obtainable by reacting di- or trialkanolamines with a mixture of fatty acids and polycarboxylic acids, and subsequently quaternizing the esters thus obtained with an alkylating agent, wherein the di- or trialkanolamines correspond to formula (I) wherein R1< and R2< independently represent hydroxyalkyl groups with 1 to 20 carbon atoms, hydroxyalkenyl groups with 2 to 20 carbon atoms and 1, 2, or 3 double bonds, or addition products of 1 to 20 and preferably 2 to 5 moles of ethylene oxide to a hydroxyethyl group, and R3< represents hydrogen, an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms and 1, 2, or 3 double bonds, a hydroxyalkyl group with 1 to 20 carbon atoms, a hydroxyalkenyl group with 2 to 20 carbon atoms and 1, 2, or 3 double bonds, or addition products of 1 to 20 and preferably 2 to 5 moles of ethylene oxide to a hydroxyethyl group, and wherein the fatty acids correspond to formula (II), R 4 -COOH (II) wherein R 4< represents an aliphatic, linear or branched hydrocarbon residue with 5 to 29 carbon atoms and 0, 1, 2 or 3 double bonds, and where the polycarboxylic acids of formula (III) correspond wherein Y represents a carbon atom or a saturated or unsaturated aliphatic hydrocarbon group with 2 to 5 carbon atoms, which may carry one or more hydroxyl groups, and X represents hydrogen, a hydroxyl group, or a carboxylic acid group.

[0011] Another aspect of the present invention relates to the use of the esterquats according to the invention as a collector in the flotation of non-sulfide minerals or ores.

[0012] Another object of the present invention relates to a process for the flotation of non-sulfide minerals or ores, in which the esterquat according to the invention is added as a collector.

[0013] Another object of the invention relates to a process for the production of ester quats, in which di- or trialkanolamines are reacted with a mixture of fatty acids and polycarboxylic acids and the resulting esters are optionally alkoxylated and subsequently quaternized in a known manner.

[0014] In the flotation process, the raw ore is first ground and then mixed with water to form a suspension. The collector according to the invention and, if necessary, further reagents are added to this mixture, and air is blown in, forming a foam layer in which the hydrophobic mineral particles are suspended.

[0015] Surprisingly, the new esterquats have been observed to be extremely effective collectors for the flotation of non-sulfide minerals and ores, particularly with regard to the presence of silicates and / or magnesium salts in the minerals or ores. The collectors according to the present invention are more effective compared to conventional esterquats with mono- and polycarboxylic acids, while exhibiting a very high degree of biodegradability. In particular, the products have proven very useful for the separation of silicate minerals from calcite by foam flotation.

[0016] Esterification with a mixture of fatty acids and polycarboxylic acids yields new ester quats of formula (1) which, surprisingly, are distinguished from prior art products not only by particularly good environmental compatibility but also by excellent yields in flotation.

[0017] The di- or trialkanolamines of formula (I) comprise as residues R 1< and R 2< preferably hydroxyalkyl residues with 2 to 5 carbon atoms, or hydroxyalkenyl residues with 2 to 5 carbon atoms and 1, 2 or 3 double bonds, or addition products of 2 to 5 mol of ethylene oxide to a hydroxyethyl residue.

[0018] R 3< preferably represents alkyl groups with 1 to 20 carbon atoms, alkenyl groups with 2 to 20 carbon atoms, hydroxyalkyl groups with 2 to 5 carbon atoms or hydroxyalkenyl groups with 2 to 5 carbon atoms and 1, 2, or 3 double bonds.

[0019] Preferred di- or trialkanolamines of formula (I) are methyldiethanolamine (MDA), diethanolamine (DEA), diethoxylated oleylamines and triethanolamine (TEA).

[0020] In a particularly preferred embodiment of the present invention, triethanolamine is used.

[0021] In the fatty acids of formula (II) R 4< preferably represents an aliphatic, linear or branched residue with 7 to 21 carbon atoms and 0, 1, 2 or 3 double bonds.

[0022] Preferred fatty acids are aliphatic carboxylic acids selected from the group consisting of caprylic acid, capric acid, lauric acid, undecylenic acid, isotridecanoic acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, isostearic acid, oleic acid, petroselinic acid, elaidic acid, petroselinic acid, linoleic acid, linolenic acid, elaeostearic acid, arachidic acid, gadoleic acid, behenic acid, erucic acid, and cetoleic acid, as well as their technical mixtures. These carboxylic acids are formed, for example, by the pressure cleavage of natural fats and oils, by the reduction of aldehydes from Roelen's oxo synthesis, or by the dimerization of unsaturated fatty acids. The aforementioned fatty acids can be used in their hydrogenated or partially hydrogenated form if they are unsaturated.

[0023] Technical fatty acid mixtures containing fatty acids with 12 to 18 carbon atoms, such as coconut oil, palm oil, palm kernel oil or tallow fatty acids, are also preferred.

[0024] The polycarboxylic acid of formula (III) preferably comprises as residue Y a saturated or unsaturated aliphatic hydrocarbon group with 3 or 4 carbon atoms, which may optionally bear one or more hydroxyl groups.

[0025] Preferred polycarboxylic acids are propane-1,2,3-tricarboxylic acid, aconitic acid, isocitric acid and especially citric acid.

[0026] The fatty acids and polycarboxylic acids can preferably be used in a molar ratio of fatty acid to polycarboxylic acid of 1:10 to 10:1. It has proven particularly advantageous to use a molar ratio of 1:1 to 8:1.

[0027] The di- or trialkanolamines on the one hand and the acids - i.e. fatty acids and polycarboxylic acids taken together - on the other hand can preferably be used in the molar ratio of di- or trialkanolamines to acids of 1:0.25 to 1:3.0, in particular in the molar ratio of 1:0.6 to 1:1.5.

[0028] The esterification can be carried out in a manner known per se, for example as described in WO 91 / 01295. In an advantageous embodiment, the reaction is carried out at temperatures between 120 °C and 220 °C, and particularly from 140 °C to 200 °C, and pressures of 0.01 to 1 bar. A catalyst can be used to accelerate the esterification reaction. Suitable catalysts are acids, preferably hypophosphorous and phosphorous acids and their alkali salts, preferably sodium hypophosphite, which can be used in amounts of 0.001 to 0.5 wt%, and preferably in amounts of 0.005 to 0.15 wt% based on the starting materials.

[0029] It is possible to use mixtures of fatty acids and polycarboxylic acids for esterification, or to carry out the esterification with the two components one after the other.

[0030] With regard to particularly high color quality and stability, the co-use of alkali and / or alkaline earth borohydrides, such as potassium, magnesium, and especially sodium borohydride, in the esterification has proven advantageous. These compounds are typically used in amounts of 50 to 1000 ppm and especially 100 to 500 ppm – again based on the starting materials – as described in application DE-C1-44 09 322.

[0031] Treating the esters with peroxide compounds or a mixture of peroxide compounds and alkali boranates prior to quaternation also leads to high color quality and stability. Besides percarboxylic acids and percarbonates, hydrogen peroxide is preferably suitable as a peroxide compound. Alkali boranates include lithium, potassium, and preferably sodium boranate. Advantageously, the peroxide compounds and the alkali boranates are each used in amounts of 0.005 to 0.1, preferably 0.03 to 0.06 wt% – based on the esterification products – as described in DE 43 08 792.

[0032] Two alternative methods can be used to produce ester quats containing polyalkylene oxides. One option is to use ethoxylated alkanolamines. This has the advantage that the alkylene oxide distribution in the resulting ester quat is approximately the same with respect to the OH groups of the amine. However, a disadvantage is that the esterification becomes more difficult for steric reasons. The preferred method is therefore to alkoxylate the ester prior to quaternation. This can be done in a known manner, i.e., in the presence of basic catalysts and at elevated temperatures. Suitable catalysts include, for example, alkali and alkaline earth hydroxides and alcoholates, preferably sodium hydroxide and especially sodium methoxide. The amount used is typically 0.5 to 5% and preferably 1 to 3% by weight, based on the starting materials. When using these catalysts, primarily free hydroxyl groups are alkoxylated.

[0033] However, if calcined or fatty acid-hydrophobized hydrotalcites are used as catalysts, insertion of the alkylene oxides into the ester bonds also occurs. This method is preferred when an alkylene oxide distribution similar to that obtained with alkoxylated di- or trialkanolamines is desired. Ethylene oxide, propylene oxide, and mixtures thereof (random or block distribution) can be used as alkylene oxides. The reaction is typically carried out at temperatures in the range of 100 to 180 °C. The incorporation of an average of 1 to 10 moles of alkylene oxide per mole of ester increases the hydrophilicity of the ester quats, improves their solubility, and reduces their reactivity towards anionic surfactants.

[0034] The quaternization of the esters can be carried out in a manner known per se. Although the reaction with the alkylating agents can also be carried out in the absence of solvents, the co-use of at least small amounts of water or short-chain alcohols, preferably isopropyl alcohol, is recommended for the preparation of concentrates having a solids content of at least 40% and, in particular, at least 60% by weight. In this invention, the term short-chain alcohols means a carbon chain length of C1 to C10.

[0035] Suitable alkylating agents include alkyl halides such as methyl chloride, dialkyl sulfates such as dimethyl sulfate or diethyl sulfate, or dialkyl carbonates such as dimethyl carbonate or diethyl carbonate. Preferably, the alkylation is a methylation or an ethylation, particularly a methylation.

[0036] The esters and alkylating agents are typically used in a molar ratio—based on the nitrogen content of the ester—of approximately 1:0.50 to 1:1.05, preferably 1:0.90 to 1:0.98. The reaction temperature is usually between 40 and 110 °C, and particularly between 50 and 80 °C. Following the reaction, it is recommended to destroy any unreacted alkylating agent by adding, for example, ammonia, an alkanolamine, an amino acid, or an oligopeptide, as described, for example, in DE-A1-40 26 184.

[0037] In certain cases, it may be advantageous to modify, adapt, or even enhance the properties of esterquats by adding a defined co-collector, such as cationic or amphoteric surfactants.

[0038] Cationic surfactants that can be used as co-collectors should be selected from, in particular: primary aliphatic amines, alkylenediamines with alpha-branched alkyl groups, hydroxyalkyl-substituted alkylenediamines, water-soluble acid addition salts of these amines, quaternary ammonium compounds, in particular quaternized N,N-dialkylaminoalkylamines.

[0039] Suitable primary aliphatic amines are primarily C8-C22 fatty amines derived from fatty acids of natural fats and oils. Typical examples include n-octylamine, n-decylamine, n-dodecylamine, n-tetradecylamine, n-hexadecylamine, n-octadecylamine, n-eicosylamine, n-docosylamine, n-hexadecenylamine, and n-octadecenylamine. These amines can be used individually as co-collectors, although amine mixtures with alkyl and / or alkenyl groups from the fatty acid fraction of animal or vegetable fats and oils are more commonly used.

[0040] Suitable alkyl-substituted alkylenediamines for use as co-collectors correspond to formula (IV), in the R 6< and R 7< represent linear or branched alkyl or alkenyl groups and are in the n2 to 4 range.

[0041] The preparation of these compounds and their use in flotation is described in DD 64275.

[0042] Suitable hydroxyalkyl-substituted alkylenediamines for use as co-collectors correspond to formula (V), in the R 8< and R 9< represent hydrogen and / or linear alkyl groups with 1 to 18 carbon atoms, the sum of the carbon atoms of R 8< + R 9< is 9 to 18, and n2 is 4.

[0043] The preparation of compounds of formula (V) and their use in flotation is described in DE-AS 2547987.

[0044] The amine compounds mentioned above can be used as such or in the form of their water-soluble salts. In certain cases, the salts are obtained by neutralization with equimolar amounts, excesses, or deficiencies of acid. Suitable acids include, for example, sulfuric acid, phosphoric acid, acetic acid, and formic acid.

[0045] Suitable quaternary ammonium compounds for use as co-collectors correspond to formula (VI), in which R 10< is a linear alkyl group with 1 to 18 carbon atoms, R 11< is an alkyl group with 1 to 18 carbon atoms or a benzyl group, and R 12< and R 13< can be the same or different and each represent an alkyl group with 1 to 2 carbon atoms, and X represents a halide anion, in particular a chloride ion.

[0046] Quaternary ammonium compounds are preferred in which R 10< is an alkyl group with 8 to 18 carbon atoms and R 11< , R 12< and R 13< are the same and represent either methyl or ethyl groups, and X is a chloride ion.

[0047] The particularly preferred cationic co-collectors comprise quaternized N,N-dialkylaminoalkylamides, preferably conforming to formula (VII), in the R 14< -CO represents an aliphatic, linear or branched acyl group with 6 to 22 carbon atoms, preferably with 12 to 18 carbon atoms, and containing 0, 1, 2 or 3 double bonds, [A] represents a linear or branched alkylene group with 1 to 4, preferably 2 or 3, carbon atoms, R 15< , R 16< and R 17< may be the same or different and each represent a methyl or ethyl group, and X is a halide or an alkyl sulfate, in particular methosulfate anion.

[0048] Coconut fatty acid N,N-dimethylaminopropylamide is preferred. These products can also be prepared by known methods, e.g., by reamidation of N,N-dimethylaminopropane with hydrogenated coconut glycerides and subsequent quaternation using dimethyl sulfate. Preferably, a mixture of collector and co-collector is prepared by mixing the esters and the N,N-dialkylalkylamides and then jointly quaternizing them.

[0049] According to the invention, the ampholytic surfactants that can be used as co-collectors contain at least one anionic and one cationic group in the molecule. Preferably, the anionic groups are sulfonic acid or carboxyl groups, and the cationic groups are amino groups, preferably secondary or tertiary amino groups. Suitable ampholytic surfactants are selected in particular from Sarcosides, taurides, N-substituted aminopropionic acids and N-(1,2-dicarboxyethyl)-N-alkylsulfosuccinic acid esters.

[0050] Suitable sarcosides for use as co-collectors correspond to formula (VIII) in which R 18< is an alkyl group with 7 to 21 carbon atoms, preferably 11 to 17 carbon atoms.

[0051] These sarcosides are known compounds that can be obtained using established methods. Their use in flotation is described by H. Schubert in "Aufbereitung fester mineralischer Rohstoffe (Dressing fester mineralischer Rohstoffe)", 2nd edition, Leipzig 1977, pp. 310-311, and the references cited therein.

[0052] Suitable taurides for use as co-collectors correspond to formula (IX) in the R 19< is an alkyl group with 7 to 21 carbon atoms, preferably 11 to 17 carbon atoms.

[0053] These taurides are known compounds that can be obtained by known methods. The use of taurides in flotation is known; see H. Schubert, loc. cit.

[0054] Preferred N-substituted aminopropionic acids suitable for use as co-collectors correspond to formula (X) in the n0 is a number from 1 to 4, and R 20< represents an alkyl or acyl group with 8 to 22 carbon atoms.

[0055] The aforementioned N-substituted aminopropionic acids are also known compounds that can be obtained by known methods. Their use as collectors in flotation is described by H. Schubert, loc. cit. and in Int. J. Min. Proc. 9 (1982), pages 353–384.

[0056] According to the invention, suitable N-(1,2-dicarboxyethyl)-N-alkylsulfosuccinic acid esters for use as a co-collector correspond to formula (XI) in the R 21< stands for an alkyl group with 8 to 22 carbon atoms, preferably 12 to 18 carbon atoms, and M stands for a hydrogen ion, an alkali metal cation or an ammonium ion, preferably a sodium ion.

[0057] The aforementioned N-(1,2-dicarboxyethyl)-N-alkylsulfosuccinic acid esters are known compounds that can be obtained by known methods. Their use as collectors in flotation is also known; see H. Schubert, loc. cit.

[0058] Preferably, the esterquats and the co-collectors according to the invention are used in a weight ratio of about 10:90 to about 90:10, preferably about 25:75 to about 75:25 and most preferably about 40:60 to about 60:40.

[0059] To achieve economically viable results in the flotation of non-sulfide minerals or ores, the collectors or mixtures of collectors and co-co ...

[0060] The quantities in which the collectors are used according to the invention are regulated by the type of minerals or ores and depend on the initial content of the valuable minerals. Accordingly, the specific quantity can vary within wide limits. In general, the collectors and collector / co- ...

[0061] Typical steps in the flotation process generally include, firstly, the dry or preferably wet grinding of the minerals or ores, the suspension of the resulting ground mineral or ore in water in the presence of the flotation reagents, and preferably, after a contact time of the flotation reagents, the injection of air into the apparatus. The nature of the starting materials and the flotation aids are illustrated in more detail below.

[0062] Floatable minerals and ores can be divided into two groups: polar and nonpolar materials. Since nonpolar minerals and ores are difficult to hydrate, they are classified as hydrophobic. Examples of nonpolar minerals include graphite, molybdenite, diamond, coal, and talc, which are already floatable in their naturally occurring state. In contrast, polar minerals and ores have strong covalent or ionic surface bonds that are accessible through rapid hydrogenation by water molecules in the form of multilayers. These starting materials are, for example, B. Calcite, malachite, azurite, chrysocolla, wulfenite, cerussite, witherite, magnesite, dolomite, smithsonite, rhodochrosite, siderite, magnetite, monazite, hematite, goethite, chromite, pyrolusite, borax, wolframite, columbite, tantalite, rutile, zircon, hemimorphite, beryl, mica, biotite, quartz, Feldspar, kyanite and garnet.The flotation of non-sulfide, but polar minerals and ores is a preferred objective of the present invention.

[0063] The flotation behavior of the individual mineral components can be controlled to some extent by the particle size distribution of the ground mineral. Conversely, the particle size can also influence the choice of collector or collector / co-collector mixture. Generally speaking, however, as particle size increases, the particles must also be more hydrophobized before they float, which is achieved by a higher dosing rate. As a general rule, the ores must be ground so finely that the individual particles consist of only one type of mineral, either the valuable minerals or the impurities. The ideal particle size usually needs to be determined depending on the specific mineral. In this case, a particle size distribution of approximately 5 to 500 µm has proven effective, although in some cases a narrower particle size distribution may be more practical.

[0064] For example, silicate-rich ores can be excellently flotationed using the flotation collectors of the present invention if less than 40 wt.% (weight percent), preferably 30 wt.%, and particularly preferably less than 15 wt.% of the mineral or ore to be flotationed is smaller than 250 µm. To achieve optimal flotation, it has been found that the fraction larger than 125 µm should be less than 15 wt.%, preferably less than 10 wt.%, and most preferably less than 5 wt.% of the mineral or ore. The lower limit of the particle size is determined both by the possibility of mechanical size reduction and by the properties of the mineral constituents during flotation. Generally, the proportion of particles with a diameter smaller than 50 µm should be 30 or even 40 wt.%. However, according to the present invention, it is particularly advantageous if more than 40 wt.% of the particles with a diameter smaller than 50 µm is less than 250 µm.-% of the particles are smaller than 45 µm.

[0065] Additional reagents that modify the surface tension or surface chemistry of the minerals or ore can be used for flotation. Besides the collectors and co-collectors already mentioned above, foamers, pH regulators, activators, and pressure boosters are also used as needed.

[0066] In certain cases, however, it may be necessary or at least advantageous to use a foaming agent, depending on the flotation method employed. The addition of a foaming agent is necessary when the foaming properties of the collector or the collector / co-collector mixture are insufficient to produce a sufficiently thick foam layer that remains stable enough during the flotation process to collect the mineral particles. Suitable foaming agents include aliphatic alcohols, natural oils, glycols, and glycol ethers.

[0067] In specific cases, however, it may be necessary or at least advantageous, depending on the flotation method used, to employ a suppressor. The addition of a suppressor is necessary when the flotation of certain minerals must be inhibited to achieve the desired yield and concentration. Natural polysaccharides such as guar gum, starch, and cellulose are used as suppressors. Quebracho, tannin, dextrin, and other chemical derivatives can also be used, particularly derivatives of starch, guar gum, and cellulose molecules, whose hydroxyl groups can possess a wide range of anionic, cationic, and non-ionic functions.

[0068] To adjust the rheological behavior of the collectors, the addition of solvent in an amount of 5 to 50 wt.%, preferably in an amount of 5 to 40 wt.%, and most preferably in an amount of 5 to 30 wt.%, is helpful in flotation according to the present invention. Suitable solvents are, for example, aliphatic alcohols with short chain lengths. Thus, the flotation aids according to the present invention can contain small amounts of glycols, for example ethylene glycol, propylene glycol, or butylene glycol, as well as monohydric linear or branched alcohols, for example ethanol, n-propanol, or isopropanol.

[0069] A further object of the present invention is the use of esterquats as a collector for the foam flotation of non-sulfide minerals or ores. According to the invention, the collectors are used in the flotation of non-sulfide minerals or ores containing, among other things, quartz, kaolin, mica, phlogopite, feldspar, silicates, and iron oxides. Examples Production example 1

[0070] 528 g (1.9 mol) of partially hydrogenated palm oil fatty acid, 212 g (1.1 mol) of citric acid, and 0.3 g of hypophosphoric acid were placed in a reactor with stirring and heated to 120 °C at a reduced pressure of 20 mbar. Subsequently, 447 g (3 mol) of triethanolamine were added portionwise, raising the temperature to 130 °C. After the addition was complete, the mixture was heated to 160 °C, the pressure was reduced to 3 mbar, and the mixture was stirred under these conditions for at least 10 h until the acid number had decreased to below 5 mg KOH / g and a typical consistency was achieved. The mixture was then cooled to 60 °C, the vacuum was broken by introducing nitrogen, and 0.6 g of hydrogen peroxide in the form of a 30 wt% aqueous solution was added.For the quaternation, the resulting ester was dissolved in 376 g of isopropyl alcohol and, over a period of 1 h, 357 g (2.83 mol) of dimethyl sulfate (DMS) were added at a rate such that the temperature did not exceed 65 °C. After the addition was complete, the mixture was stirred for a further 2.5 h, during which time the residual DMS content and total nitrogen content were regularly checked by sampling. The reaction was stopped once a constant total nitrogen content was reached and no DMS was detected. A product with a solids content of 80 wt% was obtained. Production example 2

[0071] 902 g (3.2 mol) of oleic acid, 113 g (0.65 mol) of aconitic acid, and 0.9 g of hypophosphorous acid were placed in a reactor with stirring and heated to 100 °C under a reduced pressure of 20 mbar. Subsequently, 447 g (3 mol) of triethanolamine were added dropwise, raising the temperature to 120 °C. After the addition was complete, the mixture was heated to 200 °C, the pressure was reduced to 3 mbar, and the mixture was stirred under these conditions for at least 6 h until the acid number had decreased to below 5 mg KOH / g and a typical consistency was achieved. The mixture was then cooled to 60 °C, the vacuum was broken by introducing nitrogen, and 0.6 g of hydrogen peroxide in the form of a 30 wt% aqueous solution was added.For the quaternation, the resulting ester was dissolved in 736 g of isopropyl alcohol and 357 g (2.83 mol) of dimethyl sulfate were added over 1 h at a rate that kept the temperature below 65 °C. After the addition was complete, the mixture was stirred for a further 2.5 h, with regular sampling to check the residual DMS content and total nitrogen content. The reaction was stopped when a constant total nitrogen content was reached and no DMS was detected. A product with a solids content of 70 wt% was obtained. Production example 3

[0072] 590 g (2.1 mol) of distilled mixed fatty acids (mainly C16-C20) and 230 g (1.2 mol) of citric acid were placed in a reactor with stirring and heated to a maximum of 120 °C. Subsequently, 447 g (3 mol) of triethanolamine were added dropwise, raising the temperature to a maximum of 130 °C. After the addition was complete, the mixture was heated to 180 °C and stirred under these conditions for at least 10 h until the acid number had decreased to below 5 mg KOH / g and a typical consistency was achieved. For quaternation, the resulting ester was dissolved in 610 g of isopropyl alcohol and 357 g (2.83 mol) of dimethyl sulfate were added over 1 h at a rate such that the temperature did not exceed 65 °C. After the addition was completed, the mixture was stirred for a further 2.5 hours, during which the residual DMS content and total nitrogen content were regularly checked by taking samples.The reaction was stopped after a constant total nitrogen content was reached and no DMS was detected. A product with a solids content of 70 wt% was obtained. Production example 4

[0073] 28 g (0.2 mol) of caprylic acid and 23 g (0.12 mol) of citric acid were placed in a reactor with stirring and heated to a maximum of 120 °C. Subsequently, 192 g (0.45 mol) of Genamin C050 (a C12 / C14 amine with 5 mol of ethylene oxide) were added dropwise, causing the temperature to rise to a maximum of 130 °C. After the addition was complete, the mixture was heated to 180 °C and stirred under these conditions for at least 10 h until the acid number had decreased to below 5 mg KOH / g and a typical consistency was achieved. For quaternation, the resulting ester was dissolved in 286 g of isopropyl alcohol and 53.7 g (0.43 mol) of dimethyl sulfate were added over 1 h at a rate such that the temperature did not exceed 65 °C. After the addition was completed, the mixture was stirred for a further 2.5 hours, during which the residual DMS content and total nitrogen content were regularly checked by taking samples.The reaction was stopped after a constant total nitrogen content was reached and no DMS was detected. A product with a solids content of 50 wt% was obtained. Comparison example [WO2008089906]

[0074] In a stirred reactor, 567 g (2.1 mol) of partially hydrogenated palm fatty acid, 219 g (1.5 mol) of adipic acid, and 0.3 g of hypophosphoric acid were placed in the reactor under stirring and heated to 70 °C at a reduced pressure of 20 mbar. Subsequently, 447 g (3 mol) of triethanolamine were added portionwise, causing the temperature to rise to a maximum of 120 °C. After the addition was complete, the mixture was heated to 160 °C, the pressure was reduced to 3 mbar, and the mixture was stirred under these conditions for 2.5 h until the acid number had decreased to a value below 5 mg KOH / g.

[0075] The mixture was then cooled to 60 °C, the vacuum was broken by introducing nitrogen, and 0.6 g of hydrogen peroxide in the form of a 30 wt% aqueous solution was added. For quaternation, the resulting ester was dissolved in 376 g of isopropyl alcohol and, over a period of 1 h, 357 g (2.83 mol) of dimethyl sulfate (DMS) were added at a rate such that the temperature did not rise above 65 °C. After completion of the addition, the mixture was stirred for a further 2.5 h, during which time the residual DMS content and

[0076] The total nitrogen content was regularly checked by taking samples. The reaction was stopped after a constant total nitrogen content was reached and no DMS was detected. A product with a solids content of 80 wt% was obtained. Application examples

[0077] The following examples demonstrate the superior efficacy of the novel esterquats of the invention compared to prior art collector components from WO-2008 / 089906, particularly in comparison to conventional polymeric esterquats synthesized with mono- and diaacids. The tests were conducted under laboratory conditions, and therefore the parameters used may differ from those encountered in practice. The quantities of reagents specified refer to the active substance.

[0078] Flotation under laboratory conditions was carried out according to the state of the art. The separation of the acid-insoluble minerals, which are silicates, from calcite by reverse flotation is achieved by feeding the ground starting material into a flotation cell. In the flotation cell, the starting material is suspended in water. After adding a silicate collector and allowing a conditioning period, the flotation begins. The silicates collect in the foam phase, while the calcite remains in the flotation cell.

[0079] The following examples illustrate the effectiveness of the collectors of the present invention compared to conventional polymeric ester quats synthesized with mono- and diaacids in the flotation of silicate-containing calcite minerals. The results are shown in Table 1. Grain size distribution: 60 wt.% of all particles > 45 µm Acid-insoluble 2.8 to 3.5 wt.% Calcite: approx. 96.5 - 97.2 wt.% Table 1: Calcite Flotation Test Results Test results Dosage g / t Mass of mountains Mass Concentrate Concentrate content HCl-Insoluble Calcite loss (Active salary) [g] [g] [%] [%] Comparison example 510 268.8 1447.2 0.01 13.9 425 204.3 1511.7 0.03 10.1 310 128.7 1587.3 0.07 5.6 Production example 1 510 106.1 1609.9 0.01 8.7 425 73.2 1642.8 0.05 2.4 310 58.8 1657.3 0.13 1.6 Production example 2 425 178.5 1537.5 0.01 8.6 320 110.9 1605.1 0.04 4.6 Production example 3 370 189.0 1527.0 0.01 9.2 280 133.9 1582.1 0.01 5.9 210 68.5 1647.6 0.05 2.5 Production example 4 645 136.3 1579.7 0.02 6.1 510 106.1 1609.9 0.02 4.3 325 65.4 1650.6 0.09 1.9

[0080] Calcite loss represents the amount of calcite that is carried away during reverse flotation along with silicates, iron oxides, and other impurities. The content of HCl-insoluble solids in the concentrate represents the impurities of silicates, iron oxides, etc., present in the purified calcite. The goal is to minimize both calcite loss and the content of HCl-insoluble solids in the concentrate.

[0081] The products of production examples 1-4 allow for improved reverse calcite flotation compared to the reference example. This is also shown graphically in Figure 1 shown.

Claims

1. Esterquats obtainable by reacting di- or trialkanolamines with a mixture of fatty acids and polycarboxylic acids and quaternizing the resultant esters subsequently with an alkylating agent, where the di- or trialkanolamines conform to the formula (I) in which R1 and R2 independently of one another are hydroxyalkyl radicals having 1 to 20 carbon atoms, hydroxyalkenyl radicals having 2 to 20 carbon atoms and 1, 2, or 3 double bonds, or adducts of 1 to 20 mol of ethylene oxide onto a hydroxyethyl radical, and R3 is hydrogen, an alkyl radical having 1 to 20 carbon atoms, an alkenyl radical having 2 to 20 carbon atoms and 1, 2, or 3 double bonds, a hydroxyalkyl radical having 1 to 20 carbon atoms, a hydroxyalkenyl radical having 2 to 20 carbon atoms and 1, 2, or 3 double bonds, or adducts of 1 to 20 mol of ethylene oxide onto a hydroxyethyl radical, and where the fatty acids conform to the formula (II),         R4-COOH     (II) in which R4 is an aliphatic, linear or branched hydrocarbon radical having 5 to 29 carbon atoms and 0, 1, 2, or 3 double bonds, characterized in that the polycarboxylic acids conform to the formula (III) in which Y is a carbon atom or a saturated or unsaturated, aliphatic hydrocarbon group having 2 to 5 carbon atoms and optionally carrying one or more hydroxyl groups, and X is hydrogen, a hydroxyl or a carboxylic acid group.

2. Esterquats according to Claim 1, characterized in that the di- or trialkanolamines of the formula (I) comprise as radicals R1 and R2, independently of one another, hydroxyalkyl radicals having 2 to 5 carbon atoms or hydroxyalkenyl radicals having 2 to 5 carbon atoms and 1, 2, or 3 double bonds, or adducts of 2 to 5 mol of ethylene oxide onto a hydroxyethyl radical.

3. Esterquats according to Claim 1 and / or 2, characterized in that R3 represents alkyl radicals having 1 to 20 carbon atoms, alkenyl radicals having 2 to 20 carbon atoms, hydroxyalkyl radicals having 2 to 5 carbon atoms, or hydroxyalkenyl radicals having 2 to 5 carbon atoms and 1, 2, or 3 double bonds.

4. Esterquats according to Claim 1, characterized in that the di- or trialkanolamines of the formula (I) are selected from the group consisting of methyldiethanolamine (MDA), diethanolamine (DEA), diethoxylated oleylamines, and triethanolamine (TEA).

5. Esterquats according to one or more of Claims 1 to 4, characterized in that in the fatty acids of the formula (II), R4 is an aliphatic, linear or branched radical having 7 to 21 carbon atoms and 0, 1, 2, or 3 double bonds.

6. Esterquats according to one or more of Claims 1 to 4, characterized in that the fatty acids of the formula (II) are selected from the group consisting of caprylic acid, capric acid, lauric acid, undecylenic acid, isotridecanoic acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, isostearic acid, oleic acid, petroselinic acid, elaidic acid, linoleic acid, linolenic acid, eleostearic acid, arachidic acid, gadoleic acid, behenic acid, erucic acid, and cetoleic acid, and also technical mixtures thereof.

7. Esterquats according to one or more of Claims 1 to 6, characterized in that the polycarboxylic acid of the formula (III) comprises as radical Y a saturated or unsaturated aliphatic hydrocarbon group having 3 or 4 carbon atoms and optionally carrying one or more hydroxyl groups.

8. Esterquats according to one or more of Claims 1 to 6, characterized in that the polycarboxylic acid is selected from the group consisting of propane-1,2,3-tricarboxylic acid, aconitic acid, isocitric acid and, in particular, citric acid.

9. Esterquats according to one or more of Claims 1 to 8, characterized in that the fatty acids and the polycarboxylic acids are used in a molar ratio of 1:10 to 10:1.

10. Esterquats according to one or more of Claims 1 to 9, characterized in that the di- or trialkanolamines on the one hand and the total amount of the fatty acids and polycarboxylic acids on the other hand are used in a molar ratio of 1:0.25 to 1:3.0.

11. Esterquats according to one or more of Claims 1 to 9, characterized in that an alkylating agent selected from the group consisting of alkyl halides, dialkyl sulfates, and dialkyl carbonates is used.

12. Esterquats according to Claim 11, characterized in that alkyl is methyl or ethyl.

13. Use of esterquats according to one or more of Claims 1 to 12 as collectors for the froth flotation of non-sulfidic minerals and ores, characterized in that the ore is a calcite mineral.

14. Method for flotation of calcite mineral, wherein the calcite mineral is mixed with water and an esterquat according to one or more of Claims 1 to 12 to form a suspension, air is introduced into the suspension, and the floated froth is removed.

15. Method according to Claim 14, characterized in that quaternized N,N-dialkylaminoalkylamides of the formula (VII), in which R14-CO is an aliphatic, linear or branched acyl radical having 6 to 22 carbon atoms and containing 0, 1, 2, or 3 double bonds, [A] is a linear or branched alkylene radical having 1 to 4 carbon atoms, R15, R16 and R17 may be identical or different and each denote a methyl or ethyl radical, and X is a halide or an alkylsulfate anion, are used as co-collectors.

16. Method according to Claim 15, characterized in that the esterquat according to one or more of Claims 1 to 12 and the co-collector of formula (VII) are used in a weight ratio of 10:90 to 90:10.