RU2702044C2 - Use of an emulsifier in a flotation agent composition - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: disclosed invention relates to a composition of a floatation agent used for froth flotation of non-sulphide ores, particularly phosphate ores. Flotation reagent composition suitable for use in froth flotation of non-sulphide ores contains a surface-active primary floatation agent selected from a group consisting of fatty acids, sulphonates, alkyl phosphates, alkyl sulphates and a secondary floatation agent containing a mixture of at least one compound (i) selected from a group of alkoxylates of branched fatty alcohols with 12–16 carbon atoms, having a branched degree of 1–3.5, with a degree of ethoxylation of up to 4, and at least one compound (ii) selected from a group of alkoxylates of non-ionic hydrocarbon compounds with a degree of ethoxylation higher than 3, where if both compounds (i) and (ii) are ethoxylated alcohols, the mixture has a bimodal distribution degree of ethoxylation.

EFFECT: higher efficiency of froth flotation.

4 cl, 2 dwg, 2 tbl

Description

FIELD OF THE INVENTION

The present invention relates to the use of emulsifiers in secondary flotation agent compositions containing branched alcohol and / or alkoxylate, and to the use of such compositions for foam flotation of non-sulfide ores, in particular phosphate ores, in combination with a primary flotation agent, which is an anionic or amphoteric surface active compound.

State of the art

Phosphate rocks contain minerals based on calcium phosphate, mainly in the form of apatite, usually together with other minerals, for example, silicate minerals and carbonate minerals such as calcite. Apatite is a generic name for a group of calcium phosphate-based minerals that also contain other elements or radicals, such as fluorapatite, chlorapatite, carbonyl-enriched hydroxylapatite, fluorapatite and hydroxylapatite-enriched carbonate.

It is well known to isolate valuable phosphate minerals from gangue using the foam flotation method, where phosphate minerals are enriched during flotation.

Good performance of the foam flotation process is achieved by combining, on the one hand, a good separation of valuable mineral from waste rock using selective flotation agent, and on the other hand, the characteristics foam. Characteristics of the foam include both quantity and stability of the foam. For the flotation method, it is important that the foam collapses as quickly as possible after it leaves the flotation chamber during the next stage of the enrichment method. Too stable a foam will cause both particle trapping and problems with pumping the foam product. Capture, especially on a large scale, will result in a decrease in selectivity (varietal content, extraction). Problems with pumping the foam product will make the flotation process technically impossible.

Flotation agent performance can be improved using combinations of flotation agents from the primary (main) flotation agent and a secondary flotation agent (additional flotation agent). In this document, the term “flotation agent composition” will be used to describe compositions containing both primary and secondary flotation agent.

For many decades, secondary flotation agents have been used together with primary ionic flotation agents in the flotation of salt-type minerals to improve the performance of the primary flotation agent. Nonyl phenol ethoxylates are the predominant non-ionic surfactants used as an additional flotation agent in combination with primary flotation agents such as sarcosine in the selective flotation of apatite from calcite-containing ores.

US patent No. 4814070 describes the flotation of non-sulfide ores, where alkyl sulfosuccinates based on propoxylated and ethoxylated C8-C22 fatty alcohols are used as a flotation agent. However, fatty alcohols having a high degree of branching are not discussed or described anywhere or in this document in the sense that they can be used without the sulfosuccinate functional group.

US Patent No. 4,789,466 describes the flotation of apatite ores using a flotation agent composition that contains two components, where one is an ethoxylated and propoxylated fatty alcohol and the other is a cationic, anionic or ampholytic surfactant, preferably a sulfosuccinamate surfactant. The surfactant is a primary flotation agent, and the alkoxylated fatty alcohol is a secondary flotation agent in the method of flotation of apatite ores. The degree of branching of the fatty alcohol used is either not described or fatty alcohols are used, which are known to have a degree of branching of 1 or less. In addition, US Patent No. '466 does not describe mixtures of two alkoxylated alcohols, where one is relatively highly branched and ethoxylated with 1-4 ethylene oxide groups and the other has more EO groups than the first alkoxylated alcohol. This document also does not describe the use of such mixtures as a secondary flotation agent in the flotation of apatite ores or does not speak about the advantages of this.

SE 409291 describes a foam flotation method for minerals containing calcium phosphate using an amphoteric surfactant as a primary flotation agent. The flotation ability of the primary flotation agent can be further enhanced by the presence of a secondary flotation agent, which is described as a polar, water-insoluble, hydrophobic substance that has an affinity for mineral particles that are coated with the primary flotation agent. Examples of polar components are, for example, water-insoluble soaps, such as calcium soaps, water-insoluble surfactant adducts of alkylene oxides, organic phosphate compounds, such as tributyl phosphate, and carbonic esters, such as tributyl ester of nitrilotriacetic acid. In the working examples, nonylphenol, which reacts with two moles of ethylene oxide, is used as a secondary flotation agent.

The secondary flotation agent described in SE'291 is still considered a good choice for ore processing, as it provides excellent recovery of minerals with a grade of P ₂ O ₅ above 30%. However, due to environmental problems, an intensive search has been made for the replacement of nonyl phenol ethoxylates for a long time.

EP 0 270 933 A2 describes, as flotation agents for the flotation of non-sulfide ores, mixtures that contain a polyethylene glycol alkyl or alkenyl ether with a hydrophobic group at the end and an anionic surfactant. The alkyl radicals or alkenyl ethers of polyethylene glycol having attached terminal groups in some embodiments are based on a fatty alcohol, preferably a C12-C18 fatty alcohol. In the Comparative Examples in EP 0 270 933, fatty alcohols without attached final groups are also used together with anionic surfactants. EP 0 270 933 does not describe the use of fatty alcohols having a branching degree of 1-3 and the molecules illustrated in EP'933, although they are more environmentally friendly than nonyl phenol ethoxylates, do not work as well as these nonyl phenol ethoxylates in as flotation agents for the flotation of non-sulfide ores from the point of view of the extraction of minerals with the desired high grade contents.

Thus, it is still needed in secondary flotation agents having better environmental properties than nonyl phenol ethoxylates, and which also work well.

Pending joint application PCT appl No. EP 2015/071003 describes the use of a secondary flotation agent suitable for use with the primary flotation agent of amphoteric or anionic type for foam flotation of non-sulfide ores in the extraction of oxides, carbonates, phosphates and other salt-type minerals, in particular minerals containing salt calcium phosphate, where the secondary flotation agent is a compound based on a branched fatty alcohol selected from the group of fatty alcohols with 12-16 carbon atoms having a degree of IMPLEMENT 1-3 and their alkoxylates with a degree of ethoxylation of up to 3.

SUMMARY OF THE INVENTION

The present invention has found that a secondary flotation agent that can be used in combination with a primary flotation agent of amphoteric or anionic type for foam flotation of non-sulfide ores, for the extraction of oxides, carbonates, phosphates and other salt-type minerals, in particular minerals containing calcium phosphate, where the secondary flotation agent is a mixture containing at least one compound (i) selected from the group of branched fatty alcohols with 12-16 carbon atoms having a degree of branching of 1-3.5, and their alk silates with a degree of ethoxylation (DE) of up to 4 and at least one compound (ii) selected from the group of alkoxylates of nonionic hydrocarbon compounds such as fatty amines, fatty alcohols, fatty (di) ethanolamides, fatty acids, triglycerides with a degree of ethoxylation (DE) above 3 and carbohydrate-based surfactants leads to the same good efficiency in the recovery of apatite in the presence of silicate and / or carbonate minerals as when using a secondary flotation agent containing only compound (i), and the same good environmental properties, in particular compared to nonylphenol ethoxylates, but that compound (ii) further has the advantage that it helps to emulsify compound (i) in the flotation agent composition, making it possible to more efficiently use compound (i), for example, using it in smaller quantities.

Description of drawings

Figure 1 is a distribution of the degree of ethoxylation in a mixture of the present invention.

Figure 2 is a flowchart of a flotation procedure.

DETAILED DESCRIPTION OF THE INVENTION

In one aspect, the present invention relates to a mixture (secondary flotation agent) of at least one compound (i) selected from the group of branched fatty alcohols with 12-16 carbon atoms having a degree of branching of 1-3.5, and their alkoxylates with a degree of ethoxylation of up to 4 and at least one compound (ii) selected from surfactants based on carbohydrates and alkoxylates of nonionic hydrocarbon compounds with a degree of ethoxylation of more than 3, such as alkoxylates of hydrocarbon compounds from the group of fatty alcohols, fatty amines, fatty ethanolamides, fatty diethanolamides, fatty acids, triglycerides with a degree of ethoxylation greater than 3, where when both compounds (i) and (ii) are ethoxylated alcohols, the mixture has a bimodal distribution of the degree of ethoxylation.

It should be noted that a mixture of compounds (i) and (ii) in embodiments where both compounds are ethoxylated alcohol compounds has a bimodal distribution DE (bimodal means a statistical distribution with two maxima). Or, in other words, a mixture is not an initial mixture of several molecules, which is obtained when a single ethoxylation reaction occurs with a hydrocarbon compound, and where some more or less ethoxylated molecules always form, and where the DE distribution would be unimodal (i.e., had one maximum). Instead, in the present invention, the mixture is a mixture obtained by mixing two separately ethoxylated alcohol compounds (i) and (ii).

If both compounds (i) and (ii) are ethoxylated, the degree of ethoxylation of compound (ii) is preferably higher than that of compound (i).

In addition, the present invention relates to the use of a mixture of the above compounds (i) and (ii) as secondary flotation agents for foam flotation of non-sulfide ores, in particular for the extraction of minerals containing calcium phosphate, such as apatite, in combination with primary flotation agent, which is an amphoteric or anionic surfactant, and to compositions of flotation agents containing such primary and secondary flotation agents. Examples of other valuable minerals that can be extracted using this combination of primary and secondary flotation agents include scheelite, fluorite, calcite and dolomite.

In addition, the present invention relates to the use of compound (ii) as an emulsifier for compound (i) in a liquid, most obviously in a carrier fluid in which a flotation agent composition is present, or alternatively, it relates to a method for emulsifying compound (i) in liquids. This method of emulsifying compound (i) in a liquid comprises the step of adding compound (i) to a liquid and the step of adding compound (ii) to a liquid, where the stages can be carried out one after the other or simultaneously, optionally, by pre-mixing the compounds (i) and (ii ) In a preferred method, the compounds (i) and (ii) are first mixed, and the mixture thus obtained is then added to the carrier liquid. The carrier fluid for the flotation agent composition is preferably an aqueous liquid.

In preferred mixtures, the mass ratio of compound (i) to compound (ii) is from 30:70 to 99: 1, more preferably from 40:60 to 98: 2, even more preferably from 50:50 to 90:10.

By “branching degree” (DB), as used herein, is meant the total number of methyl groups present on the alkyl or alkenyl chain of the alcohol or its alkoxylate, minus one. The average number of methyl groups in the sample molecules can be easily determined using NMR spectroscopy. You must understand that the degree of branching (DB) in the C12-C16 branched fatty alcohol, which delivers a branched alkyl or alkenyl chain for compound (i), is the average degree of branching for the used fatty alcohol. Fatty alcohols are often available or used as a mixture of several components, and therefore DB should not be an integer. As a consequence, the degree of branching for compound (i) is the average degree of branching, where the average degree of branching is the statistical average value of the degree of branching of the sample molecules.

In a preferred embodiment, the DB in compound (i) is higher than 1, even more preferably higher than 1.5, most preferably higher than 2. In another more preferred embodiment, the DB is lower than 3.2, most preferably it is 3 or below. The molecular formula of the compounds of the secondary flotation agents (i) and (ii) in a preferred embodiment is

R-A (I),

where for compound (i) R is an alkyl or alkenyl group containing 12-16, preferably 12-15 carbon atoms and where said alkyl or alkenyl group has a degree of branching of 1-3, and where for compound (ii) R is any alkyl, aryl or alkenyl group, branched or linear, having 8-24 carbon atoms; A is selected from groups

O- (PO) _x (EO) _y (PO) _z H, for compounds (i) and (ii),

(CO) N (CH ₂ CH ₂ O (PO) _x (EO) _y (PO) _z H) ₂ , for compound (ii),

(CO) NH (CH ₂ CH ₂ O (PO) _x (EO) _y (PO) _z H), for compound (ii),

(CO) O ((PO) _x (EO) _y (PO) _z H), for compound (ii),

N (PO) _x (EO) _y (PO) _z H) ₂ , for compound (ii),

(CO) O ((PO) _x (EO) _y (PO) _z OCH ₂ CH (O (PO) _x (EO) _y (PO) _z O (CO) R) CH ₂ O

((PO) _x (EO) _y (PO) _z O (CO) R), for compound (ii), and

O (C ₆ H ₁₁ O ₅ ) - (O- (C ₆ H ₁₁ O ₅ )) _m , for compound (ii),

where for compound (i), PO represents a propyleneoxy unit and EO represents an ethyleneoxy unit; x represents the number 0-2, preferably 0, y represents the number 0-4, preferably 0-3, more preferably 0-2.5, even more preferably 0-2.3, and most preferably 0 -2, and z is a number 0-2, preferably 0, and where for compound (ii), PO is a propyleneoxy unit and EO is an ethyleneoxy unit; x is a number 0-20, preferably 0, y is a number above 3 and up to 30, preferably 4-20, more preferably 5-15, even more preferably 7-12, z is a number 0-20 preferably 0 and m is an integer from 0 to 5.

The mixture may further comprise additional components, such as a liquid. In preferred embodiments, the implementation of such a liquid is an aqueous liquid, even more preferably, the liquid contains more than 95% water. In such mixtures, compound (ii) acts as an emulsifier for compound (i).

As is obvious from the formula (I), for the compound (i), alcohols per se and their alkoxylates can be used in mixtures of secondary flotation agents.

Alkoxylated products in accordance with formula (I) can be obtained using procedures well known in the art, by reacting the corresponding starting alcohol, acid, amide, amine or triglyceride with ethylene oxide or propylene oxide and ethylene oxide in the presence of an appropriate catalyst, for example, a conventional basic catalyst such as KOH, or the so-called narrow range catalyst (see, for example, Nonionic Surfactants: Organic Chemistry in Surfactant Science Series volume 72, 1998, pp 1-37 and 87-107, edited by Nico M. van Os; Marcel Dekker, Inc). If both propylene oxide and ethylene oxide are used, alkoxides may be added as blocks in any order, or they may be added randomly. Products obtained from reaction with ethylene oxide only are most preferred.

Preferred compounds (i) are alkoxylates of alcohols with a degree of ethoxylation up to 3. Preferred compounds (ii) are alkoxylates of alcohols with a degree of ethoxylation above 3, even more preferably above 4. In one embodiment, their degree of ethoxylation is up to 30, preferably , up to 20. For both compounds (i) and (ii), it is preferred that they have a degree of propoxylation of less than 2, even more preferably less than 1, most preferably about 0.

Carbohydrate-based surfactants, also referred to above as having the formulas RO- (C ₆ H ₁₁ O ₅ ), in a preferred embodiment, are surfactants that are generally non-ionic and which, in a preferred embodiment implementation, contain at least one unit selected from the group of carbohydrates, such as sorbitol (sorbitans), glucose (glycosides), sucrose and / or their esters, amides.

The primary flotation agents used in the foam flotation in accordance with the present invention can be either amphoteric or anionic surfactants. The following are some examples of formulas for primary flotation agents, but these should only be considered as suitable for use in the present invention and should not be construed as limiting.

In one embodiment, the primary flotation agent for the above foam flotation procedure has the formula

where R ₁ represents a hydrocarbyl group with 8-22, preferably with 12-18 carbon atoms; A represents an alkyleneoxy group containing 2-4, preferably 2, carbon atoms; p represents the number 0 or 1; q is a number from 0 to 5, preferably 0; R ₂ represents a hydrocarbyl group containing 1-4 carbon atoms, preferably 1 atom, or R ₂ represents a group

where r_one, A, p and q have the same meaning as above; Y^- selected from the group consisting of COO^- and SO₃ ^-preferably from COO^-; n represents the number 1 or 2, preferably 1; M represents a cation, which may be monovalent or divalent, and inorganic or organic, and r represents the number 1 or 2. The primary flotation agent can also be used in its acid form, where nitrogen is protonated and external no cation is required.

Compounds in accordance with formula (II) can easily be obtained in high yield from commercially available starting materials using known procedures. US patent No. 4358368 describes some methods of obtaining compounds, where R ₁ represents a hydrocarbyl group with 8-22 carbon atoms (column 6, line 9 - column 7, line 52), and in US patent No. 4828687 (column 2, line 2 - column 2, line 31) describes compounds where R ₂ represents

присоединенную к соединению формулы (II) через метиленовую группу.

attached to the compound of formula (II) through a methylene group.

In another embodiment, the primary flotation agent has the formula (III)

where R ₂ represents a hydrocarbyl group with 8-22, preferably 12-18, carbon atoms, D represents -CH ₂ - or CH ₂ CH ₂ -, k represents the number 0-4, preferably 0-3, and most preferably 0-2, and M is hydrogen or a cation, such as a sodium or potassium cation.

These products are well known and are obtained commercially using methods well known in the art. Products where D is —CH ₂ - are obtained by reaction between a fatty amine and chloroacetic acid or its salts, and products where D is —CH ₂ CH ₂ - are obtained by reaction between a fatty amine and acrylic acid or its complex esters, in the latter case, the reaction is followed by hydrolysis.

In another embodiment, the primary flotation agent is selected from anionic surfactants, such as fatty acids (with a C8-C24 acyl group), sulfonates, alkyl phosphates, alkyl sulfates, and compounds of formula (IV)

where R represents a hydrocarbyl group containing 7-23, preferably 11-21 carbon atoms, optionally substituted; R_one represents H or CH₃preferably H; R₂ represents H or a C1-C4 alkyl group, preferably H; R₃ represents H or CH₃, preferably CH₃; n represents the number 1-20; p represents the number 1-3, preferably 1; X represents H⁺ or a cation that is organic or inorganic, and m is the valency of the cation and is a number of 1-2, preferably 1. The cation is preferably selected from the group consisting of an alkali metal cation, an alkaline earth metal cation, ammonium and a substituted ammonium group containing one or more C_one-C₃ alkyl and / or hydroxylalkyl groups.

For the preparation of compounds of formula (IV), see the description in WO 2015/000931 (corresponding to PCT / EP2014 / 064014).

You can also get a mixture of the above compounds as a primary flotation agent. In the case of mixing amphoteric and anionic surfactants as the primary flotation agent, it is preferable to have up to 20% by weight of the anionic surfactant per amount of amphoteric surfactant.

In another aspect, the present invention relates to a method for foam flotation of non-sulfide ores, in particular phosphate ores, for the extraction of apatite minerals, in this method the mixture of flotation agents described above is used.

Such a foam flotation method for phosphate ores may typically include the steps of:

a) conditioning the crushed ore, where the ore contains a phosphate-containing mineral and gangue minerals in an aqueous medium, optionally conditioning the mixture with a flotation aid (in some embodiments, a depressant); and optionally, adjusting the pH;

b) adding an aqueous composition (in some embodiments, an aqueous emulsion) containing the primary and secondary flotation agents described herein, and optionally adjusting the pH;

c) optionally adding a foaming agent; and

d) implementing a foam flotation process for recovering a phosphate-containing mineral (s).

In another aspect, the present invention relates to a composition of a flotation agent containing a primary flotation agent, as defined herein, and a mixture of a secondary flotation agent, as defined herein.

The mass ratio of the primary flotation agent and the secondary flotation agent, both in flotation agent compositions and in flotation processes, is preferably 15:85, more preferably 20:80, most preferably 25:75 to 99: 1, preferably 98: 2, most preferably 97: 3. All mass relationships in this document relate to the ratio of active materials, unless otherwise stated.

The amount of flotation agent composition added to the ore will typically be in the range of 10 to 1000 g / ton of dry ore, preferably in the range of 20 to 500, more preferably 100 to 400 g / ton of dry ore.

Additional flotation additives that may be present in the flotation process are depressants such as polysaccharide, alkaline starch or dextrin, filler oils, foaming agents / foam regulators such as pine oil, MIBC (methyl isobutyl carbinol) and alcohols such as hexanol, and alcohol ethoxylates / propoxylates, inorganic dispersants such as sodium silicate (water glass) and soda ash, and pH adjusters.

The pH during the flotation process will preferably be in the range of 8-11.

The present invention will now be illustrated by the following examples.

Examples

Example 1

General flotation procedure

Phosphate ore containing 20-25% of apatite, 30-40% of silicates and about 20% of iron oxides is broken into pieces and crushed to the desired flotation size (K80 = 110 μm).

Three alkoxylates are prepared by reacting Exxal 13 alcohol (from Exxon), which has DB 3, with ethylene oxide in an amount of 1.5, 5 and 8.5 equivalents, respectively, with respect to the molar amount of alcohol.

500 g of ore is placed in a Denver 1.4-liter flotation chamber, 500 ml of process water (25 mg / L Ca ²⁺ , 40 mg / L Mg ²⁺ ) is added and mixing is started. Then, conditioning is carried out for 5 minutes with 1000 g / ton of a 1% (w / w) starch aqueous solution, a flotation agent (600 g / ton (or a mixture of primary acyl glycidal flotation agent and secondary flotation agents) is added to the flotation chamber), as 1% aqueous solution, and continue conditioning for 2.5 minutes. After the conditioning step, tap water is added so that a total volume of 1.4 L is obtained, the pH of the flotation mixture is adjusted to 9.5 with a 10% aqueous NaOH solution and flotation begins. The experiment is carried out at room temperature (RT) (20 ± 1 ° C). A coarser flotation is carried out, followed by three stages of purification. All fractions (tails, intermediate and concentrate) are collected and analyzed. Refer to Figure 2 regarding the general procedure, which follows.

The flotation results and the composition of the preparation of the used flotation agent are shown in Table 1.

Table 1. The flotation results, presented as the extraction and varietal content of P ₂ O ₅ .

The amount of alcohol + XEO, g / ton The average degree of ethoxylation The amount of acyl glycide,
g / ton 2nd cleaner
concentrate 3rd cleaner concentrate 1,5EO 5EO 8.5EO Extraction
% Varietal content
% Recovery% Varietal content
% Comparison 1 0 0 0 0 600 82.8 32,7 78.6 34.1 The present invention 150 0 150 5 300 81.6 33,2 79.5 34.2 Comparison 2 0 300 0 5 300 76.6 33,4 72,4 35.0

As can be seen from Table 1, flotation results can only be improved by using a mixture of two non-ionic surfactants as a secondary flotation agent. Figure 1 graphically shows the distribution of the degree of ethoxylation for the preparation of the present invention and for comparative preparation 2. The results clearly show that the distribution with two peaks plays a crucial role in flotation. In combination with the primary flotation agent, a mixture of two ethoxylated alcohols with a degree of ethoxylation of 1.5 and 8.5, respectively, provides much better recovery than one ethoxylated alcohol with a degree of ethoxylation of 5.

Example 2

The formation and stability of the emulsion is examined by preparing 5% by weight aqueous solutions as follows: five (5) g of a surfactant or mixture of surfactants is added to a 150-ml beaker, diluted with 95 g of water and mixed vigorously. After 5 minutes, stirring is stopped. Visual observation of the prepared solutions is carried out after 1, 2, 3, 4, 5, 10 and 60 minutes.

The results are shown in Table 2 below.

Table 2. Results on the formation and stability of the emulsion for a mixture of two alcohol ethoxylates

Mass ratio
1,5EO: 8.5EO With stirring 1 min 2 minutes 3 min 4 min 5 minutes 10 min 60 min 100: 0 2 p 2 p 2 p 2 p 2 p 2 p 2 p 2 p 90:10 Em Em 2 p 2 p 2 p 2 p 2 p 2 p 80:20 Em Em Em Em 2 p 2 p 2 p 2 p 50:50 Em Em Em Em Em Em Em 2 p

Em means emulsion, 2p means 2 phases

Table 2 shows that the addition of a compound having an ethoxylation degree higher than 3 to the alcohol ethoxylate, which has an ethoxylation degree of only 1.5, significantly helps in the formation of an emulsion. The additional addition of a more ethoxylated product, for example, up to 50% by weight, makes the emulsion much more stable.

Claims (23)

1. Flotation agent composition suitable for use in the foam flotation process of non-sulfide ores, containing a surface-active primary flotation agent selected from the group consisting of fatty acids, sulfonates, alkyl phosphates, alkyl sulfates, compounds of formula (II)

, where R ₁ represents a hydrocarbyl group with 8-22, preferably with 12-18 carbon atoms; A represents an alkyleneoxy group containing 2-4 carbon atoms; p represents the number 0 or 1; q is a number from 0 to 5, preferably 0; R ₂ represents a hydrocarbyl group containing 1-4 carbon atoms, preferably 1 atom, or R ₂ represents a group

where R ₁ , A, p and q have the same meaning as above, Y ^{- is} selected from the group consisting of COO ^- and SO ₃ ^- , preferably from COO ^- ; n represents the number 1 or 2, preferably 1; M represents a cation, which may be monovalent or divalent and inorganic or organic, and r represents the number 1 or 2; or where compound (II) is in its protonated form without an external cation (M ^{r +} ) 1 / r; from compounds of formula (III)

, where R ₂ represents a hydrocarbyl group with 8-22, preferably with 12-18 carbon atoms, D represents -CH ₂ - or -CH ₂ CH ₂ -, k represents 0-4, preferably 0-3, and most preferably 0-2 and M represents hydrogen or a cation, such as a sodium or potassium cation; and from compounds of formula (IV)

, where R represents a hydrocarbyl group containing 7-23, preferably 11-21 carbon atoms, optionally substituted; R_one represents H or CH₃preferably H; R₂ represents H or a C1-C4 alkyl group, preferably H; R₃ represents H or CH₃, preferably CH₃; n represents the number 1-20; p represents the number 1-3, preferably 1; X represents H⁺ or a cation that is organic or inorganic, and m is the valency of the cation and is a number 1-2, preferably 1; and from mixtures thereof; and a secondary flotation agent that contains mixtures of at least one compound (i) selected from the group of alkoxylates of branched fatty alcohols with 12-16 carbon atoms having a branching degree of 1-3.5, with a degree of ethoxylation of up to 4, and at least one compound (ii) selected from the group of alkoxylates of nonionic hydrocarbon compounds with a degree of ethoxylation above 3, where, if both compounds (i) and (ii) are ethoxylated alcohols, the mixture has a bimodal distribution of the degree of ethoxylation. 2. The composition according to claim 1, where the compound (ii) is selected from the group of alkoxylates of nonionic hydrocarbon compounds from the group of fatty alcohols, fatty amines, fatty ethanolamides, fatty diethanolamides, fatty acids and triglycerides with a degree of ethoxylation greater than 3. 3. The composition according to claim 1 or 2, where the molecular formula of compounds (i) and (ii) is the formula (I) R-A (I), where for compound (i) R is an alkyl or alkenyl group containing 12-16, preferably 12-15 carbon atoms, and where said alkyl or alkenyl group has a degree of branching 1-3, and where for compound (ii) R is any alkyl, aryl or alkenyl group, branched or linear, having 8-24 carbon atoms; A is selected from groups O- (PO) _x (EO) _y (PO) _z H for compounds (i) and (ii), (CO) N (CH ₂ CH ₂ O (PO) _x (EO) _y (PO) _z H) ₂ for compound (ii), (CO) NH (CH ₂ CH ₂ O (PO) _x (EO) _y (PO) _z H) for compound (ii), (CO) O ((PO) _x (EO) _y (PO) _z H) for compound (ii), N (PO) _x (EO) _y (PO) _z H) ₂ for compound (ii), (CO) O ((PO) _x (EO) _y (PO) _z OCH ₂ CH (O (PO) _x (EO) _y (PO) _z O (CO) R) CH ₂ O and ((PO) _x (EO) _y (PO) _z O (CO) R) for compound (ii), where PO is a propyleneoxy unit and EO is an ethyleneoxy unit, and for compound (i) x is a number 0-2, preferably 0, y is a number 0-4, preferably 0-3, more preferably 0-2.5 , even more preferably 0-2.3, and most preferably 0-2, and z is a number 0-2, preferably 0, and for compound (ii) x is a number 0-20, preferably 0, y is a number above 3 and up to 30, preferably 4-20, more preferably 5-15, even more preferably 7-12, z represents oh number 0-20, preferably 0. 4. The composition according to any one of claims 1 to 3, where the mass ratio of the primary flotation agent and the secondary flotation agent is in the range between 15:85 and 99: 1.

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