EP2885080A1 - Collectors for ore enrichment - Google Patents

Abstract

The present invention relates to alcoxylated-fatty-polyamine-based collectors for the flotation enrichment of aqueous ore suspensions, and to the use of said alcoxylated-fatty-polyamine-based collectors in flotation processes for ore enrichment, more particularly in reverse flotation processes for the enrichment of ores containing silicates.

Description

 COLLECTORS FOR ENRICHMENT OF MINERALS

The present invention relates to the use of cationic collectors in flotation processes for the enrichment of ores, more particularly in reverse flotation processes for the enrichment of ores, especially for the enrichment of ores containing silicates .

Flotation consists of extracting minerals from ore suspensions, generally aqueous suspensions, making more hydrophobic (less wettable by water) particles to float, using reagents, generally called "collectors" . The direct flotation process refers to processes by which floated particles are valuable ores, while the reverse flotation process refers to processes by which floated particles are the impurities to be extracted from valuable ores.

The flotation process generally takes place in a cell containing an aqueous suspension of the ores to be treated and a generator of air bubbles. At least one collector is added and the collector or collectors adsorb on the surface of the particles of minerals or impurities to be removed (case of reverse flotation), increasing the attachment of the particles with the air bubbles during the collision. The combined air / particle bubbles, less dense than the pulp, rise to the surface, leading to the formation of a foam, which is collected by skimming or overflow.

 The flotation of minerals, such as the flotation of silica, silicates, feldspar, mica, clays, potash and other minerals, which carry a negative charge at the pH at which the flotation is carried out, is generally performed using cationic collectors. Cationic collectors are molecules that are at least partially positively charged when added in an aqueous environment at an appropriate pH.

Therefore, the term "cationic collectors" is included herein as organic collecting compounds containing at least one amino group. Such cationic collectors are already known, widely used, and include p. ex. fatty amines and their salts, fatty propylene polyamines and their salts, alkyl ether amines and alkyl ether diamines and their salts, quaternary ammonium salts, imidazoline derivatives, alkoxylated amines and the like.

More specifically, in the seventies, a combination of N-tallow-trimethylenediamine diacetate (Akzo Nobel's Duomac ^® T, CAS No. 61791-54-6) and a tertiary amine containing an alkyl group. fatty acids and two polyoxyethylene groups attached to a nitrogen (Ethomeen 18/60, adducts of 50 ethylene oxides from Akzo Nobel, CAS no. 99241 -69-7) were used to remove micaceous schist, pyrite and quartz of a calcite rock. These collectors, however, have the disadvantage of being solid, and must be dissolved in hot water before use.

 In order to avoid this problem, US Pat. No. 3,990,966 proposed the use of a flotation reagent chosen from 1-hydroxyethyl-2-heptadecenylglyoxalidine, 1-hydroxyethyl-2-alkylimidazolines and their salt derivatives. , for the removal of impurities from calcite.

 To separate the silica from other minerals such as iron ore or phosphates, etheramines and ether diamines and their salts are mentioned in US Pat. No. 4,319,987. These amines and diamines are mainly used in their forms. partially neutralized, in the form of acetates. The reason is the better solubility of the partially neutralized amino function.

[0009] U.S. Patent 5,261,539 proposed alkoxylated alkylguanidines in Cs C2 ₄ containing 1 to 10 alkoxy groups, alkoxylated fatty alkyl amines in Cs-C2 ₄ containing 1 to 6 alkoxy groups and mixtures thereof, as cationic collectors to remove quartz, micaceous minerals, chlorite, pyrite and other mineral impurities from finely ground calcium carbonate. This patent discloses higher calcium carbonate recoveries compared to Alkazene ^® , an imidazoline type collector.

US Pat. No. 4,995,965 claims a mixture containing at least one compound from the group comprising a hydroxypropylated quaternary ammonium compound, asymmetric dialkyldimethyl quaternary ammonium compounds and dialkylhexahydropyrimidine. Similarly, US Patent 5,540,337 claims a flotation material based on alkyloxyalkaneamines free of acrylonitrile.

 [0011] International Application WO 1994/026419 describes the combination of quaternary ammonium salts with an alkylene oxide adduct and an amine compound, for which the sum of all the alkylene oxide groups is 10. at 40. This combination makes it possible to obtain an improvement in the enrichment of calcium carbonate; leading to a very high yield and / or a high selectivity compared to the prior art, for example US 4,995,965.

 Another international application, WO 2007/122148, describes the combination of at least two collectors, belonging to the fatty quaternary ammonium salts or the quaternary ammonium compounds of bis-imidazoline, and more preferably a combination of two quaternary ammonium salts for the inverse foam flotation of a calcite ore.

 WO2008 / 084391 specifically claims a calcium carbonate purification process using as collector at least one compound which is a quaternary imidazolium methosulfate, more particularly the aminoethylimidazolium methylsulfate of 1-methyl- 2-noroléyl-3-oleic acid.

Even more recently, US patent application 2009/0152174 claims a mixture of alkyletheramine, alkyletherdiamine, alkylamine or a quaternary ammonium salt with a fatty triamine corresponding to the formula RN- [A]. -NH ₂ ] 2, for use as an improved collector for the flotation of silicates. Examples are given for reverse flotation of silicates in calcite. The most effective mixture indicated in the examples is a mixture of 29% fatty triamine with 71% of the standard quaternary ammonium salt (dicocoalkyldimethylammonium chloride).

A common feature of all known enrichment processes is that the collectors, which are inherently attached to the floated particles, remain in the residues. It is known that most amines and amine derivatives exhibit aquatic and environmental toxicity. In order to reduce the environmental impact, studies have been carried out to improve the performance of the flotation reagents, thus leading to a reduced dosage of the flotation reagents used. From the prior art, it is clearly taught to those skilled in the art that effective collectors for the flotation of silicates, especially in calcium carbonate ores, have been developed in recent years, these efficient collectors being mainly mixtures of cationic reagents containing at least one cationic molecule permanently charged (at least one quaternary nitrogen atom in the molecule).

 Apart from reducing the dosage of such amine collectors, another way to improve the situation with regard to environmental problems would be to use cationic molecules that are more environmentally friendly, that is to say. less toxic and / or biodegradable flotation reagents.

 DE 196 02 856 proposes the use of biodegradable quaternary ammonium esters, e.g. ex. esterquats. According to WO2007 / 122148 (see above), such esterquats degrade by hydrolysis and / or biologically during the flotation step.

However, this prior art teaches that, in the process of flotation of inverse calcite foam, fatty acids resulting from this degradation attach to calcite and also float the mineral, resulting in poor performance.

 There is therefore a continuing need to optimize or find alternatives to reverse silicate foam flotation, for example in the fortification of calcium carbonate ores.

 In the case of calcium carbonate, the effectiveness of the flotation step is evaluated by measuring the yield of the product, which must be as high as possible (low losses of calcite in the foam), and the amount of Insoluble materials in the acids in the products (remaining silicates), which should be as low as possible.

 A first object of the present invention is to provide an effective reagent for mineral mineral foam flotation, which is environmentally friendly, i.e. less toxic and / or more biodegradable than collectors already known in the state of the art.

Another object of the present invention is to provide an effective reagent (or collector) for the flotation of mineral ore foam, which is respectful of the environment, i.e. less toxic and / or more biodegradable than collectors already known in the state of the art, and which allows to obtain satisfactory enrichment yields. Other objects will be evidenced by the following description of the present invention.

It has now been discovered that the above objectives are achieved in whole or at least in part when a flotation of foam is carried out with the flotation reagent described below, also called "collector", the use of which being also an object of the present invention.

 It has indeed been found that particularly good results are obtained when the collector comprises at least one of the following compounds of formula (1) which comprises no quaternary ammonium atom.

According to a first aspect, the present invention relates to a collector for the enrichment by flotation of an aqueous suspension of ores, said collector comprising at least one compound of formula (1):

in which

 Ri represents a hydrocarbon group containing from 6 to 30 carbon atoms,

 Al represents an alkylene group containing from 1 to 6 carbon atoms,

E ₁ , E ₂ and E ₃ , which are identical or different from one another, are chosen independently from alkylene oxide groups containing from 1 to 6 carbon atoms,

N, n ₂ and n ₃ , which are identical or different from each other, and independently of each other, each represent an integer whose value is from 1 to 20, and

• p is 1, 2, 3 or 4.

The compounds of formula (1) may also be used in the form of their addition salts with one or more acids, said acid or acids being chosen from inorganic and organic acids, including, without being limited to, hydrochloric acid, acetic acid, phosphoric acid, sulfuric acid, alkane (eg, methane) sulfonic acid, toluene sulfonic acid and the like.

According to a preferred aspect of the present invention, the collector of the present invention comprises at least one compound of formula (1) as defined above, and is essentially free, more preferably is free, of any compound containing a quaternary ammonium.

The mixtures of compounds of formula (1) containing various radicals R 1 are included in the present invention, for example mixtures of compounds of formula (1) in which the various radicals R 1 contain from 16 to 18 carbon atoms.

 In the formula (1) above, and according to a first embodiment, R 1 is a linear hydrocarbon group, cyclic or branched, saturated or unsaturated, containing from 6 to 30, preferably from 8 to 26, more preferably preferred from 12 to 22 carbon atoms, said group optionally containing one or more rings.

 According to another embodiment, preferred compounds of formula (1) are those in which A 1 represents an alkylene group containing from 1 to 6 carbon atoms, preferably from 2 to 6 carbon atoms, more preferably 2, 3 or 4 carbon atoms. Preferred compounds of formula (1) are those wherein A 1 is propylene.

According to another preferred embodiment, E ₁ , E ₂ and E ₃ are chosen from methylene oxide - (CH ₂ -O) -, ethylene oxide - (CH ₂ -CH ₂ -O) ) -, propylene oxide - (CH ₂ -CH (CH ₃ ) -O) - and / or - (CH (CH ₃ ) -CH ₂ -O) -, and butylene oxide - (CH ( CH ₂ -CH ₃ ) -CH ₂ -O) - and / or - (CH ₂ -CH (CH ₂ -CH ₃ ) -O) -, E ₁ , E ₂ and E ₃ being connected to the nitrogen atom respective by their sp ₂ carbon atom. Preferably, E ₁ , E ₂ and E ₃ are selected from ethylene oxide - (CH ₂ -CH ₂ -O) -, and propylene oxide - (CH ₂ - CH (CH ₃ ) -O) and / or - (CH (CH ₃ ) -CH ₂ -O) -. More preferably, from 70 mole% to 100 mole% of all the alkylene oxide groups present in the compound of formula (1) are ethylene oxide groups, and 0 mole% to 30 mole%. moles are propylene oxide groups. Even more preferably, E ₁ , E ₂ and E ₃ are identical radicals and are selected from ethylene oxide and propylene oxide. Even more preferably, E ₁ , E ₂ and E ₃ are all identical radicals and are ethylene oxide groups. It should also be understood that E ₁ , E ₂ and E ₃ can each comprise two or more different alkylene oxide groups, which can be arranged in a sequenced or random distribution.

According to another embodiment, the compounds of formula (1) are those in which ni, n ₂ and n ₃ , which are identical or different, independently represent an integer whose value is from 1 to 10, so that more preferably 1 to 5, even more preferably 1 to 3. Preference is also given to compounds of formula (1) wherein the sum of n + n ₂ + n ₃ is strictly less than 10.

 In the compounds of formula (1) described above, p is preferably 1 or 2. More preferably, p is 1.

According to a preferred embodiment, the compound of formula (1) above has one or more of the following characteristics:

 R 1 represents a linear or branched hydrocarbon group containing from 6 to 30 carbon atoms, preferably from 8 to 26, more preferably from 12 to 22 carbon atoms, optionally containing one or more unsaturations, in the form of a or more than one double and / or three

A 1 represents a linear or branched alkylene group containing from 1 to 6 carbon atoms, preferably from 2 to 6 carbon atoms, particularly preferably 2, 3 or 4 carbon atoms,

E ₁ , E ₂ and E ₃ , identical to or different from each other, are independently selected from the group ethylene oxide (EO), the propylene oxide group (OP) and the butylene oxide group (OB), preferably from the EO group and the OP group, more preferably, E i, E ₂ and E ₃ each represent an EO group,

N, n ₂ and n ₃ , which are identical or different, independently represent an integer whose value is from 1 to 20, preferably from 1 to 10, and the sum

P is 1, 2, 3 or 4, preferably 1 or 2, p being more preferably 1. According to another preferred embodiment, the compound of formula (1) above has one or more of the following characteristics:

 R 1 represents a linear alkyl group containing from 8 to 26, more preferably from 12 to 22 carbon atoms,

Al represents a linear alkylene group containing from 2 to 4 carbon atoms, for example a - (CH ₂ ) 3 (propylene) group,

E ₁ , E ₂ and E ₃ , identical to or different from each other, are independently selected from the group E E and the group OP, more preferably E ₁ , E ₂ and E ₃ each represent an EO group,

N, n ₂ and n ₃ , which are identical or different, independently represent an integer whose value is from 1 to 5, preferably from 1 to 3, and the sum ni + n ₂ + n ₃ ranges from 3 to 9 , for example the sum ni + n ₂ + n ₃ is 3,

 P is 1 or 2, and preferably 1.

 According to another preferred embodiment, the compound of formula (1) above has all the following characteristics:

 R 1 represents a linear alkyl group containing from 8 to 26, more preferably from 12 to 22 carbon atoms,

Al represents a linear alkylene group containing from 2 to 4 carbon atoms, for example a - (CH ₂ ) ₃ (propylene) group,

E ₁ , E ₂ and E ₃ , identical to or different from each other, are independently selected from the group E E and the group OP, more preferably E ₁ , E ₂ and E ₃ each represent an EO group,

N, n ₂ and n ₃ , which are identical or different, independently represent an integer whose value is from 1 to 5, preferably from 1 to 3, and the sum ni + n ₂ + n ₃ ranges from 3 to 9 , for example the sum ni + n ₂ + n ₃ is 3,

 P is 1 or 2, and preferably 1.

More preferably, the compounds of formula (1) are chosen from alkoxylated fatty C ₆ -C ₃ o -polyamine alkyls, and even more advantageously from ethoxylated or propoxylated fatty C ₆ -C ₃ o-diamino diamines. In the description of the present invention, "polyamine" refers to a compound comprising two or more amine groups, the amino groups being optionally substituted, i.e. that the two or more amino groups may be the same or different and may be primary, secondary or tertiary amine groups.

The compounds of formula (1) are commercially available or can be prepared by known preparation techniques.

For example, the compounds of formula (1) can easily be obtained by condensation of a fatty polyamine with one or more alkylene oxides. A typical example of a compound of formula (1) is an ethoxylated tallow diamine, for example a tallow diamine reacted with 3 molecules of ethylene oxide, typically N ', N', N'-tri hydroxyethyl-N-tallow (or arachidyl or behenyl) propylenediamine (tallow diamine or arachidyl- or behenyl-diamine with 3 moles of ethylene oxide), having a CAS No. 61790-85-0.

 This compound is particularly interesting because it is liquid at room temperature, easy to handle, easily dispersible in water, i.e. does not need to be totally or partially salified, at the dosage level used in the flotation process (typically from 10 ppm to 1000 ppm). Moreover, this compound is biodegradable.

 As other compounds of formula (1), there may be mentioned various compounds of alkoxylated propylenediamine, among which may be mentioned for example N, N ', N'-tri-hydroxyethyl-N-oleylpropylenediamine (No. CAS 103625-43-0), N, N ', N'-tri-hydroxyethyl-N-laurylpropylenediamine (CAS No. 25725-44-4), propoxylated N-tallow-alkyltrimethylenediamines (CAS No. 68603-75- 8), and the like.

The collector of the present invention, for the enrichment by flotation of aqueous suspensions of ores, may consist of one or more compounds of formula (1) as defined above, alone. Alternatively, one or more of the compounds of formula (1) may advantageously be formulated with any one or more conventional additives known in the field of flotation.

Nonlimiting examples of such additives are pH adjusting agents, such as sodium or potassium carbonate and sodium or potassium hydroxide; solvents (water, organic solvents and mixtures thereof); depressants, such as starch, quebracho, tannin, dextrin and guar gum, and polyelectrolytes, such as polyphosphates and waterglass, which have a dispersing effect, often combined with a depressing effect. Other additives Foaming agents (foaming agents), such as methylisobutylcarbinol, thethoxybutane, pine oil, terpineol and polypropylene oxide and its alkyl ethers, among which methylisobutylcarbinol, thethoxybutane, pine oil, terpineol are preferred foaming agents. As non-limiting examples, preferred conventional additives are generally foaming agents, of which terpineol is the most commonly used.

According to another preferred embodiment, the compound of formula (1) can also advantageously be formulated with any other conventional collector compound known in the field of flotation, provided that:

The collector mixtures of quaternary ammonium compounds with the compound (1) in which the sum ni + n ₂ + n ₃ is 10 or more and 40 or less, and

 The collecting mixtures of primary monoamines, of etheramines or of ether diamines with the compound (1),

are excluded from the present invention.

In the above definition, "etheramines" and "ether diamines" mean compounds comprising at least one ether group and respectively an NH ₂ terminal group and an NH ₂ terminal group, as well as another primary, secondary amine group. or tertiary.

 Examples of conventional collectors that can be used with the compound of formula (1) include, but are not limited to:

. alkoxylated fatty amines and their salts,

 • fatty poly (alkyleneamines) and their salts, e.g. ex. poly (ethyleneamines), poly (propyleneamines) and their salts, as well as their alkoxylated derivatives,

 . fatty amidopolyamines and their salts, as well as their alkoxylated derivatives,

Fatty amideopoly (alkyleneamines) and their salts, as well as their alkoxylated derivatives,

 Fatty imidazolines and their salts, as well as their alkoxylated derivatives,

• N-fatty alkylaminocarboxylic acids and their salts, e.g. ex. N-fatty alkylaminopropionic acids and their salts,

• and the like Specific examples of cationic compounds that can be used with the compound of formula (1) as a collector according to the present invention include, but are not limited to, ethoxylated tallow monoamine, 1,3-propanediamine-N diacetate. (CAS No. 6891 1-78-4), compounds having CAS No. 91001 -82-0, such as N, N ', N'-trihydroxyethyl-N-behenyl-propylenediamine, fatty alkylimidazoline obtained by condensation of diethylenetriamine and an oleic fatty acid, isodecyloxypropyl-1,3-diaminopropane (CAS No. 72162-46-0), N, N-di (tallow carboxyethyl) -N-hydroxyethyl methylsulphate N-methylammonium (CAS No. 91 995-81-2), N-cocoaminopropionic acid (CAS No. 84812-94-2), N-laurylaminopropionic acid (CAS No. 1462- 54-0), N-myristyl-β-aminopropionic acid (CAS No. 14960-08-8), their addition salts with one or more acids, the sodium salt of N-lauryl- aminopropionic acid (CAS No. 3546-96-1), salt N-laurylaminaminopropionic acid triethanolamine (CAS No. 14171-00-7), triethanolamine salt of N-myristylaminopropionic acid (CAS No. 61791 -98-8), and the like as well as mixtures of two or more of the above compounds in all proportions.

Specific examples of cationic compounds which can be used with the compound of formula (1) as a collector according to the present invention also include, but are not limited to, dicocodimethylammonium chloride (CAS No. 61789-77-3). ), cocodimethylbenzylammonium chloride (CAS No. 61789-71 -7), tallow dimethylbenzylammonium chloride (CAS No. 61789-75-1), and the like, provided that the sum of ni + n ₂ + n ₃ in the compound of formula (1) is less than 10.

According to another preferred embodiment, the collector of the present invention comprises from 1% by weight to 100% by weight of at least one compound of formula (1), more preferably from 10% by weight to 100% by weight, typically from 20% by weight to 100% by weight, of at least one compound of formula (1), advantageously from 1% by weight to 99% by weight of at least one compound of formula (1) ), more preferably from 10% by weight to 99% by weight, typically from 20% by weight to 99% by weight of at least one compound of formula (1), based on the total amount of the compound (s) of formula (1) and other cationic compounds. According to a particularly advantageous embodiment of the present invention, the collector according to the present invention comprises at least one compound of formula (1) as described above, and at least one compound of formula (2):

in which

 R21 represents a hydrocarbon group containing from 6 to 30 carbon atoms

 R22 and R23, which are identical or different, each independently represent a hydrocarbon group containing from 1 to 6 carbon atoms

R2 ₄ represents hydrogen or a hydrocarbon group containing from 1 to 6 carbon atoms,

A ₂ represents an alkylene group containing from 1 to 6 carbon atoms, and

• q is 1, 2, 3 or 4.

 The mixtures of compounds of formula (2) containing various radicals R21 are included in the present invention, for example mixtures of compounds of formula (2) in which the various radicals R21 contain from 16 to 18 carbon atoms.

 In the above formula (2), R21 is a linear, cyclic or branched, saturated or unsaturated hydrocarbon group, preferably a linear or branched unsaturated hydrocarbon group, containing from 6 to 30, preferably from 8 to 26, of more preferably from 12 to 22 carbon atoms, said group optionally containing one or more rings.

The compounds of formula (2) may also be used in the form of their addition salts with one or more acids, said acid or acids being chosen from inorganic and organic acids, including, without being limited to, hydrochloric acid, acetic acid, phosphoric acid, sulfuric acid, alkane (eg, methane) sulfonic acid, toluene sulfonic acid and the like. Preferred compounds of formula (2) are those having one or more of the following characteristics:

• R ₂₂ and R ₂ 3, which are identical or different, each independently represent a hydrocarbon group containing 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and are preferably selected from methyl, ethyl, propyl and butyl,

• R ₂₂ and R ₂ 3 are the same,

R ₂₄ represents hydrogen,

A ₂ represents an alkylene group containing 1, 2, 3 or 4 carbon atoms, A ₂ is preferably ethylene or propylene, A ₂ is more preferably propylene, and

 Q is 1 or 2, q being preferably 1.

 The compounds of formula (2) are commercially available or may be prepared by known preparation techniques.

For example, the compounds of formula (2) can easily be obtained by condensation of an unsaturated fatty acid (eg rapeseed oil, tall oil) with an amine compound of formula (2 '). ):

wherein R _22, R ₂ 3, R _24, A ₂ and q are as defined above.

[0058] dimethylaminopropylamine condensation products with an unsaturated fatty acid Ci ₆ -C _8, such as rapeseed oil (CAS No. 85408-42-0) or tall oil (CAS No. 68650-79- 3) are particularly interesting because they are liquid at room temperature (easy to handle), easily dispersible in water, i.e. do not need to be totally or partially salified, at the dosage level used in the flotation process (typically from 10 ppm to 1000 ppm), and have the additional advantage of being biodegradable.

Other examples of compounds of formula (2) are the condensation products of dimethylaminopropylamine with a coconut, palm, tallow and / or oleic fatty acid, and / or with a Ci ₂ fatty acid (p (eg, lauric), and / or with a C 1 fatty acid (eg ricinoleic), and / or with a C ₂ -C ₂₂ fatty acid, and / or like. Other examples of compounds of formula (2) are those having the following CAS numbers: 68188-30-7, 69278-64-4, 691400-76-7, 165586-99-2, 226994-25-8, 97552 -95-9, which are respectively the condensation products of dimethylaminopropylamine with soybean oil, castor oil, peanut oil, almond oil, avocado, fish oil.

The collector according to the present invention thus preferably comprises, and more preferably consists of:

 At least one compound of formula (1) as defined above;

 Optionally, at least one compound of formula (2) as defined above;

 Optionally one or more additives conventionally used in the state of the art, and for example chosen from pH adjusting agents, depressants, polyelectrolytes, foaming agents and the like.

 More specifically, the collector according to the present invention preferably comprises, and more preferably consists of:

 At least one compound of formula (1) as defined above;

 At least one compound of formula (2) as defined above;

 Optionally one or more additives conventionally used in the state of the art, and for example chosen from pH adjusting agents, depressants, polyelectrolytes, foaming agents and the like.

 Even more specifically, the collector according to the present invention preferably comprises, and more preferably consists of:

 A compound of formula (1) as defined above;

 At least one compound of formula (2) as defined above;

 Optionally one or more additives conventionally used in the state of the art, and for example chosen from pH adjusting agents, solvents, depressants, polyelectrolytes, foaming agents and the like.

 Even more specifically, the collector according to the present invention preferably comprises, and more preferably consists of:

 A compound of formula (1) as defined above;

A compound of formula (2) as defined above; Optionally one or more additives conventionally used in the state of the art, and for example chosen from pH adjusting agents, depressants, polyelectrolytes, foaming agents and the like.

 For example, the collector according to the present invention comprises, and preferably consists of:

 A compound of formula (1) as defined above;

 A compound of formula (2) as defined above.

 The ratio by weight between the compound (s) of formula (1) and the compound (s) of formula (2) in the collector of the present invention may vary in large proportions, without any specific limitation. According to a preferred embodiment, this weight ratio is from 1: 99 to 99: 1, more preferably from 20:80 to 80:20, even more preferably from 40:60 to 60:40. Particularly satisfactory results are obtained with a mixture of a weight ratio of 50:50 of at least one compound of formula (1) and at least one compound of formula (2), and typically with a mixture of a weight ratio of 50:50 of one or more compounds of formula (1) and one or more compounds of formula (2).

 Accordingly, and according to a second aspect, the present invention relates to the use of at least one collector, and preferably a collector, as defined above, for the direct or reverse flotation enrichment, of reverse preference, an aqueous suspension of ores containing minerals.

 The collector of the present invention is effective either in direct flotation processes or in reverse flotation processes. The collector of the present invention is particularly suitable for enriching aqueous suspensions of ores using the reverse flotation process.

The use of the present invention is particularly effective for the enrichment of all types of ores containing impurities, and more specifically for the enrichment of carbonates (calcium and / or magnesium carbonates), phosphates and phosphates. iron ores, enrichment of calcium carbonates being particularly preferred. The use of the present invention is particularly suitable for the enrichment of all types of calcium carbonates (natural or crushed), such as limestone, chalk, marble, calcite, carbonate-containing materials. calcium (minimum CaCO3 content 70%), calcium carbonates containing alkaline earth metals (eg calcium carbonate calcium or gaylussite), magnesium carbonates (eg calcium carbonates containing magnesium carbonate, such as dolomite), beryllium carbonates, strontium carbonates, barium carbonates, radium carbonates, and mixtures thereof.

 "Natural calcium carbonate" in the sense of the present invention is a calcium carbonate (calcite) obtained from natural sources, such as marble, limestone or chalk. For the purposes of the present invention, "ground calcium carbonate" (GCC) is a natural calcium carbonate which is machined by a wet and / or dry treatment such as grinding, sieving and / or fractionation, for example by a cyclone or classifier.

Other ores that can be efficiently enriched using the collectors of the present invention include wollastonite, barite, titanium oxides (eg, rutile, anatase, brookite), kaolin, kaolinitic clays ( soft white clay mainly composed of kaolinite), calcined kaolinitic clays, montmorillonite, sepiolite, talc, diatomaceous earth, aluminum oxide (eg. ex. α-ΑΙ _{February 03,} Y-Al2O3), the aluminum oxides containing other elements, such as sodium (eg diaoyudaoite), and other oxides, sulphates and sulphides, such as zinc oxides, zirconium dioxides, tin dioxide , lead carbonate, barium sulphate and zinc sulphide, including mixtures of two or more of the foregoing in all proportions.

The aforementioned ores are often defined as "white pigments". For the purposes of the present invention, a white pigment is a pigment which has a white color. The white color of the white pigments is mainly based on the relatively low absorption of light in combination with non-selective light scattering of visible light on the pigments. The White pigments in the present invention are inorganic white pigments that can be obtained naturally or synthetically.

The collectors according to the present are also effective for direct or inverse foam flotation of "non-white pigments" (as opposed to the white pigments listed above). Non-white pigments include, but are not limited to, minerals selected from phosphates, potassium chloride, ores containing a metal, "metal" meaning p. ex. iron, platinum, aluminum, nickel, copper and the like.

The minerals which are effectively removed, or at least whose content in ores is significantly reduced by flotation, may be of any type known to those skilled in the art, preferably provided that they are negatively charged to pH. which flotation is carried out. In general, said minerals include, but are not limited to, insoluble graphite, iron sulfides (eg, pyrite, marcasite, magnetopyrite, pyrrhotite, mackinawite), iron oxides (eg, wustite, magnetite) iron hydroxides and iron oxyhydroxides (eg, bernalite, goethite, lepidocrocite, feroxyhyte, ferrihydrite, schwertmannite, akaganite), silica, silicates (neosilicates, sorosilicates, cyclosilicates, inosilicates, phyllosilicates) , tectosilicates and / or amorphous silicates, such as zirconia, willemite, olivine, mullite, forsterite, aluminosilicates, fayalite, ilavite, gehlenite, epidote, kornérupine, benitonite , beryl, tourmaline, enstatite, wollastonite, rhodenite, diopside, amphibolite, grunerite, cummingtonite, actinolite, hornblende, talc, kaolin, kaolinitic clay, calcined kaolinitic clay, halloysite, d ickite, vermiculite, nontronite, sepiolite or montmorillonite, mica minerals, biotite, muscovite, phlogopite, lepidolite or glauconite, clinochlore, quartz, tridymite, cristobalite, feldspar minerals , diatomaceous earth or opal), mica, clays, potash (potassium chloride), and the like, as well as mixtures thereof. Preferably, the minerals that are effectively removed, or at least the ore content of which is significantly reduced, by direct or inverse, preferably inverse, foam flotation of ores, include silicates, preferably quartz minerals, such as quartz, tridymite and / or cristobalite, more preferably quartz, as well as mixtures of quartz and one or more additional silicates, even more preferably quartz alone.

 The use of the present invention is particularly well suited for the enrichment of calcium carbonate, and the minerals (impurities) that are effectively removed typically include silicates, preferably quartz.

 When one or more compounds of formula (1) are used with one or more other compounds as defined above, for example those of formula (2), they may be added separately, but are preferably added together under the form of an individual flotation reagent (collector).

The total content of each of the compound (s) of formula (1) and of the compound or compounds of formula (2), which may represent the total amount, by weight, of the collector according to the invention, for use in the process of flotation enrichment of an aqueous suspension of ores according to the present invention may vary within wide limits depending on the nature of the ores to be purified and the nature and amount of impurities contained therein. Generally, the total amount of collector is from 10 ppm to 5000 ppm by weight, preferably from 50 ppm to 1000 ppm, for example from 200 ppm to 500 ppm, based on the amount of ore (s) to be enriched.

 The use according to the invention of a collector comprising one or more compounds of formula (1) for the reverse flotation in ore beneficiation leads to impurities (residues) floated at least partially biodegradable, non-toxic or at least only slightly toxic. This represents a real improvement in comparison with the known collectors of the prior art. Such residues comprising floated impurities, preferably silicates, and at least one compound of formula (1) form another object of the present invention.

The invention will be further illustrated by the following examples, which show the performance of collectors in the process of flotation of silicates in calcium carbonate ores.

Examples

Flotation experiments in the laboratory are performed in an Outotec flotation cell, filled with 2 L of water. Calcium carbonate (800 g) is added to obtain a suspension at 30% by weight. The calcium carbonate sample used for the experiment contains between 2.5% by weight and 3% by weight of impurities. The flotation experiment takes place at neutral pH.

The flotation reagent (collector) is weighed and added directly into the flotation cell. The quantity introduced is expressed in ppm by weight relative to the initial amount of CaCO3 introduced into the suspension. The suspension is stirred for 5 min (conditioning time) at 1200 rpm without air bubbles, followed by 20 to 30 min maximum flotation. Air is finally bubbled into the suspension, the air flow being set at 3 L-min ^"1 .

 The purified carbonate sample is filtered, weighed after drying and analyzed. An attack of hydrochloric acid is followed by a second drying and weighing in order to measure the amount of acid-insoluble compounds (the remaining silicates). The attack of HCI aims to obtain complete dissolution of the calcium carbonate by appropriate dissolution with a concentrated solution of hydrochloric acid (typically 10%). The remaining minerals that are not digested correspond to the silicates (impurities).

 The foam is also rinsed and filtered. It is then dried, weighed, attacked with HCl, dried and weighed again to deduce the amount of impurities and losses of calcium carbonate.

The following collectors are used:

 Collector A (comparative) = dicoco chloride, dimethylammonium, CAS No. 61789-77-3, 75% by weight in isopropanol (15% by weight) and water (10% by weight);

 • B-collector (comparative) = coconut chloride, dimethylbenzylammonium CAS No. 61789-71 -7, 50% by weight in water;

 • Collector C (comparative) = mixture of

 o 82% by weight of the collector A,

o 6% by weight of ethoxylated tallow monoamine (CAS No. 61791-26-2 obtained by ethoxylation of a tallow fatty amine with 20 moles of ethylene oxide per mole of amine); o 12% by weight of 1,3-propanediamine-N-tallow diacetate, CAS No. 6891-78-4, diluted to 36% by weight in a 50/50% by weight mixture of water and 2-butoxy ethanol (CAS No. 11-176-2);

 Collector D (according to the invention, general formula (1)) = N, N ', N'-tri-hydroxyethyl-

N-tallow-propylenediamine, CAS RN 61790-85-0;

 Collector E (general formula (2)) = rapeseed oil, N- (3- (dimethylamino) propyl) amide, CAS no 85-408-42-0;

 Collector F (according to the invention, general formula (1)) = N, N ', N'-tri-hydroxyethyl-N-oleylpropylenediamine, CAS No. 103625-43-0;

 Collector G (according to the invention, general formula (1)) = N, N ', N'-tri-hydroxyethyl-N-coco-propylenediamine, CAS No. 25725-44-4;

 H collector (according to the invention, general formula (1)) = N-tallow alkyl, ethoxylated trimethylenediamine, obtained by ethoxylation of N-tallow-1,3-propylenediamine with 7 moles of ethylene oxide per mole of diamine ;

Collector I (according to the invention, general formula (1)) = ethoxylated N-arachidylbéhénylpropylènediamine, obtained by ethoxylation of N-arachidylbéhényl-1,3-propanediamine with 7 moles of ethylene oxide per mole of diamine;

 J collector (comparative) = N-tallow-alkyl, ethoxylated propylenediamine, (CAS RN 61790-85-0), obtained by ethoxylation of N-tallow-1,3-propylenediamine with 12 moles of ethylene oxide per mole diamine;

K-collector (general formula (2)) = tallol, N- (3- (dimethylamino) propyl)) amide, (CAS No. 68650-79-3);

 L collector (general formula (2)) = fish oil, N- (3- (dimethylamino) propyl) amide, (CAS No. 97552-95-9);

 M collector (according to the invention, general formula (2)) = coconut, N- (3- (dimethylamino) propyl)) amide, (CAS No. 1335203-24-1);

N-collector (comparative) = isodecyloxypropyl-1,3-diaminopropane (CAS No. 72162-46-0);

O collector (comparative) = mixture of 10% by weight of propan-2-ol and 90% by weight of N, N-di (tallow carboxyethyl) -N-hydroxyethyl-N-methylammonium methylsulfate; • Collector P (comparative) = mixture of:

 38% by weight of the collector A;

 o 56% by weight of a collector which is a mixture of 75% by weight of hydrogenated tallow dimethylbenzylammonium chloride (CAS No. 61789-75-1) in 15% by weight of propan-2-ol and 10% by weight of water weight;

o 6% by weight of a 50/50 wt% mixture of Hydrosol A200 ^® and 2-ethylhexanol (CAS No. 104-76-7);

 • Q collector (comparative) = mixture of 65% by weight of N-coco-β-aminopropionic acid (CAS no. 84812-94-2), 10% by weight of N-cocoamine (CAS RN 61788- 46-3) and 25% by weight of propan-2-ol.

Calcium carbonate enrichment tests

 Flotation of calcium carbonate is carried out as described above, using the collectors A, C, D and E mentioned above, at various concentrations. The results are shown in Table 1 below.

 - Table 1 -

These results clearly show that the collectors D and E, although they contain no quaternary ammonium group, have very good results in comparison with the standard collector A, a quaternary ammonium salt (dicoco chloride, dimethylammonium) , which is commonly used for this type of flotation. It is possible to carry out the flotation at 500 ppm with a mixture of the collectors D and E, while at this dosage, the foaming properties of the collector A are not sufficiently satisfactory to obtain adequate industrial collection of impurities.

 Collectors D and E do not require any partial salification before use, unlike the commercial etheramine and ether-diamine collectors.

The results obtained with the collector D at 500 ppm are comparable to an improved formulation of the standard collector C which is a mixture of a quaternary ammonium salt, diamine diacetate and a highly ethoxylated fatty monoamine. The collector D is biodegradable, while the formulation C contains a product which has poor biodegradability. The results given in Table 2 below show the effect of the amount of collector used:

 - Table 2 -

This example shows that the collector D is still active at 300 ppm while at the same dosage flotation can not take place with the collector C: not enough foam.

The results presented in Table 3 below make it possible to compare the efficiency of various collectors containing a component or mixtures of components, and provide comparative data for the collector mixtures D and E, according to their ratio. in weight. - Table 3 -

At a dosage of 500 ppm, in comparison with the collector E, the collector D leads to a very small amount of remaining impurities (acid-insoluble fraction of 0.1% by weight). The collector D, however, seems less selective (higher losses of CaCO3). The use of a mixture of the D and E collectors leads to a smaller quantity of impurities (0.08% instead of 0.1%), while maintaining the losses of calcium carbonate at a reasonable level ( <3%). The use of collectors containing a compound of formula (1) according to the invention provides even better results when combined / combined with a compound of formula (2). Collectors D and E are biodegradable.

It is still possible to perform a flotation at a dosage of 300 ppm with the collector D or mixtures of the collectors D and E, while the collector E alone can be considered insufficient foaming at this level of dosage. Again, better results are obtained for the mixtures, especially the 50/50 and 75/25% by weight mixtures of D and E, compared with the collectors used alone: the losses of CaCO3 are lower when mixtures are used, compared to D alone, the level of impurities is lower for the mixtures, in comparison with E alone.

 The results presented in Table 4 below illustrate the use of conventional additives (typically a foaming agent) with a collector according to the invention.

 - Table 4 -

This example clearly shows that the collector of the present invention can advantageously be formulated with well known conventional additives, such as a well-known foaming agent, terpineol in this example.

 At the same dosage level, the formulation of 90% by weight of D + 10% by weight of terpineol collects more impurities than the collector D alone, while the losses of calcite are only slightly increased.

Other results are presented in Table 5 below, indicating the role of the number of alkyleneoxy chains in the collector of general formula (1).

 - Table 5 -

Insoluble fraction

 Calcite:

 Dosage: in acid =

 Loss in the

 Collector mg collector quantity remaining

 foam (%

/ kg of CaCO ₃ of impurities (%

 weight)

 weight)

 D 300 2.71 0.70

 F 300 2.52 0.37

 H 200 1, 22 1, 68

 I 300 2.21 0.72

 Too much

J 200 Too much foam This example shows that particularly good results are obtained with the collector F. Without being bound to the theory, it seems that the efficiency of the collector depends on the length of the chains and the ethoxylation level of the collector. The highly ethoxylated diamines (see manifold J containing 12 ethylene oxides per mole of diamine) can not provide satisfactory reflective effect when used alone because of their excessive foaming behavior. Moreover, the collector J is not biodegradable.

The results of Table 6 below show that the collector according to the present invention is much more effective than a conventional collector already known for the flotation of silicates (collector N), such as an ether diamine: no need to salification, better purity, while maintaining losses of CaCO ₃ at a reasonable level. Furthermore, the foam obtained with the collector N is very liquid, which makes the collection of impurities difficult.

 - Table 6 -

Additional comparative results are presented in Table 7 below, showing that a collector according to the invention (collector D + collector E) provides better results than another type of biodegradable collector. The collector O is also not very foaming, leading to a crust above the foam, which could lead to problems on an industrial scale during skimming. - Table 7 -

 The comparative results provided in Table 8 below clearly show that the biodegradable mixture of D and E according to the present invention makes it possible to obtain better results (losses much lower, with better purity) than a compound. quaternary ammonium compound according to WO 2007/122148.

 - Table 8 -

 The comparative results provided in Table 9 below show that a collector according to the present invention containing 3 ethyleneoxy groups mixed with a quaternary ammonium compound, or an N-alkylaminopropionic acid leads to satisfactory results. terms of enrichment.

 - Table 9 -

Insoluble fraction

Dosage: Calcite:

 in acid = mg of loss in the

 Collector quantity remaining collector / kg foam (%

of impurities (% in of CaC0 ₃ weights)

 weight)

 D 300 2.71 0.7

90% by weight D +

 300 3.07 0.40

 10% by weight B

 90% by weight D +

 300 4.1 0.47

10% by weight Q J 300 Too much foam Too much foam

90% by weight D +

 300 Too much foam Too much foam 10% by weight B

An improved purity is obtained by mixing the collectors D and B (90/10% by weight) or D and Q (90/10% by weight), in comparison with D alone, however with a quantity of ore loss. of slightly higher interest. In comparison, the use of a collector comprising a highly ethoxylated molecule (collector J) mixed with the same quaternary ammonium compound (collector B) does not improve the flotation results.

Claims

1. Collector for the enrichment by flotation of an aqueous suspension of ores, said collector comprising at least one compound of formula (1): in which  Ri represents a hydrocarbon group containing from 6 to 30 carbon atoms,  Al represents an alkylene group containing from 1 to 6 carbon atoms, E ₁ , E ₂ and E ₃ , which are identical or different from one another, are chosen independently from alkylene oxide groups containing from 1 to 6 carbon atoms, N, n ₂ and n ₃ , which are identical or different from each other, and independently of each other, each represent an integer whose value is from 1 to 20, and • p is 1, 2, 3 or 4. Collector according to claim 1, having one or more of the following characteristics:  R 1 represents a linear or branched hydrocarbon group containing from 6 to 30 carbon atoms, preferably from 8 to 26, more preferably from 12 to 22 carbon atoms, optionally containing one or more unsaturations, in the form of a or more than one double and / or three  A 1 represents a linear or branched alkylene group containing from 1 to 6 carbon atoms, preferably from 2 to 6 carbon atoms, particularly preferably 2, 3 or 4 carbon atoms, E ₁ , E ₂ and E ₃ , which are identical or different from one another, are chosen independently from the group ethylene oxide (EO), the oxide group propylene (OP) and the butylene oxide (OB) group, preferably from the EO group and the OP group, more preferably, E ₁ , E ₂ and E ₃ each represent an EO group, N, n ₂ and n ₃ , which are identical or different, independently represent an integer whose value is from 1 to 20, preferably from 1 to 10, and the sum  P is 1, 2, 3 or 4, preferably 1 or 2, p being more preferably 1. 3. Collector according to claim 1 or 2, having one or more of the following characteristics:  R 1 represents a linear alkyl group containing from 8 to 26, more preferably from 12 to 22 carbon atoms, Al represents a linear alkylene group containing from 2 to 4 carbon atoms, for example a - (CH ₂ ) 3 (propylene) group, E ₁ , E ₂ and E ₃ , identical to or different from each other, are independently selected from the group E E and the group OP, more preferably E ₁ , E ₂ and E ₃ each represent an EO group, N, n ₂ and n ₃ , which are identical or different, independently represent an integer whose value is from 1 to 5, preferably from 1 to 3, and the sum ni + n ₂ + n ₃ ranges from 3 to 9 , for example the sum ni + n ₂ + n ₃ is 3,  P is 1 or 2, and preferably 1. Collector according to one of Claims 1 to 3, having all of the following characteristics:  R 1 represents a linear alkyl group containing from 8 to 26, more preferably from 12 to 22 carbon atoms, Al represents a linear alkylene group containing from 2 to 4 carbon atoms, for example a - (CH ₂ ) ₃ (propylene) group, E ₁ , E ₂ and E ₃ , identical to or different from each other, are independently selected from the group E E and the group OP, more preferably E ₁ , E ₂ and E ₃ each represent an EO group, N, n ₂ and n ₃ , which are identical or different, independently represent an integer whose value is from 1 to 5, preferably from 1 to 3, and the sum ni + n ₂ + n ₃ ranges from 3 to 9 , for example the sum ni + n ₂ + n ₃ is 3,  P is 1 or 2, and preferably 1. 5. Collector according to any one of claims 1 to 4, comprising at least one compound of formula (1) and one or more collectors chosen from: . alkoxylated fatty amines and their salts,  Fatty poly (alkyleneamines) and their salts, as well as their alkoxylated derivatives, fatty amidopolyamines and their salts, as well as their alkoxylated derivatives, Fatty amideopoly (alkyleneamines) and their salts, as well as their alkoxylated derivatives,  Fatty imidazolines and their salts, as well as their alkoxylated derivatives, • N-fatty alkylaminocarboxylic acids and their salts,  • and the like Collector according to any one of claims 1 to 5, also comprising at least one compound of formula (2): in which  R21 represents a hydrocarbon group containing from 6 to 30 carbon atoms,  R22 and R23, which are identical or different, each independently represent a hydrocarbon group containing from 1 to 6 carbon atoms, R2 ₄ represents hydrogen or a hydrocarbon group containing from 1 to 6 carbon atoms, A ₂ represents an alkylene group containing from 1 to 6 carbon atoms, and • q is 1, 2, 3 or 4. The collector of claim 6, wherein the compound of formula (2) has one or more of the following characteristics: • R ₂₂ and R ₂ 3, which are identical or different, each independently represent a hydrocarbon group containing 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and are preferably selected from methyl, ethyl, propyl and butyl, • R ₂₂ and R ₂ 3 are the same, R ₂₄ represents hydrogen, A ₂ represents an alkylene group containing 1, 2, 3 or 4 carbon atoms, A ₂ is preferably ethylene or propylene, A ₂ is more preferably propylene, and  Q is 1 or 2, q being preferably 1. 8. Collector according to any one of claims 6 and 7, comprising and preferably consisting of:  At least one compound of formula (1);  Optionally, at least one compound of formula (2);  Optionally one or more additives conventionally used in the state of the art, and for example chosen from pH adjusting agents, depressants, polyelectrolytes, foaming agents and the like. 9. A collector according to any one of claims 6 to 8, comprising and preferably consisting of:  At least one compound of formula (1);  At least one compound of formula (2);  Optionally one or more additives conventionally used in the state of the art, and for example chosen from pH adjusting agents, depressants, polyelectrolytes, foaming agents and the like. 10. Use of a collector according to any one of claims 1 to 9 for the enrichment by flotation of an aqueous suspension of ores containing minerals. 11. Use according to claim 10, wherein the ores are selected from calcium carbonates, magnesium carbonates, phosphates and iron ores. 12. Use according to any one of claims 10 or 1 1, wherein the ores are selected from limestone, chalk, marble, calcite, materials containing calcium carbonate, calcium carbonates containing alkaline metals -terrous, magnesium carbonates, beryllium carbonates, strontium carbonates, barium carbonates, radium carbonates, and mixtures thereof. 13. Use of a collector according to claim 10, wherein the ores are selected from wollastonite, barite, titanium oxides, kaolin, kaolinitic clays, calcined kaolinitic clays, montmorillonite, sepiolite, talc. , diatomaceous earths, aluminum oxides, aluminum oxides containing other elements, as well as other oxides, sulphates and sulphides, such as zinc oxides, zirconium dioxides, tin, lead carbonate, barium sulphate and zinc sulphide, including mixtures of two or more of the foregoing in all proportions. 14. Use of a collector according to claim 10, wherein the ores are selected from phosphates, potassium chloride, metal-containing ores, "metal" meaning iron, platinum, aluminum, nickel, copper and the like. 15. Use according to any one of claims 10 to 14, wherein the total content of the collector is in the range of 10 ppm to 5000 ppm by weight, preferably 50 ppm to 1000 ppm, for example 200 ppm to 500 ppm of the ore (s) to be enriched. Use according to any one of claims 10 to 15, wherein the minerals include insoluble graphite, iron sulfides, iron oxides, iron hydroxides and iron oxyhydroxides, silica, silicates, mica, clays, potash and the like, and mixtures thereof, preferably quartz. 17. Residues comprising floated impurities, preferably silicates, and at least one compound of formula (1) as defined in any one of claims 1 to 9.