WO2017162563A2

WO2017162563A2 - Use of emulsifier in collector composition

Info

Publication number: WO2017162563A2
Application number: PCT/EP2017/056516
Authority: WO
Inventors: Henrik NORDBERG; Natalija Smolko-Schvarzmayr; Magnus Svensson
Original assignee: Akzo Nobel Chemicals International B.V.
Priority date: 2016-03-22
Filing date: 2017-03-20
Publication date: 2017-09-28
Also published as: BR112018015843B1; CA3016794A1; EP3433021A2; BR112018015843A2; RU2019107595A; RU2687665C1; RU2019107595A3; WO2017162563A3; EP3433021B1; ZA201804773B; CA3016794C; RU2702044C2

Abstract

The present invention relates to secondary collector mixtures containing at least one compound (i) selected from the group of branched fatty alcohols with 12-16 carbon atoms having a degree of branching (DB) of 1-3.5 and their alkoxylates 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 with a degree of ethoxylation of higher than 3 and carbohydrate-based surfactants, wherein if both compounds (i) and (ii) are ethoxylated alcohols, the mixture has a bimodal degree of ethoxylation distribution; to the use of compound (ii) as an emulsifier for compound (i) in a liquid; to collector compositions containing the secondary collector mixtures together with a primary collector that is an amphoteric or anionic surface-active compound; and to the use of the above compositions in a process for froth flotation of non-sulfidic ores.

Description

USE OF EMULSIFIER IN COLLECTOR COMPOSITION Field of Invention

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

Background of the invention

Phosphate rocks contain calcium phosphate minerals largely in the form of apatite, usually together with other minerals, e.g. silicate minerals and carbonate minerals, such as calcite. Apatite is a generic name for a group of calcium phosphate minerals also containing other elements or radicals, such as fluorapatite, chlorapatite, hydroxylapatite, carbonate-rich fluorapatite and carbonate-rich hydroxylapatite. It is well-known to separate the valuable phosphate minerals from the gangue by using a froth flotation process where the phosphate minerals are enriched in the float.

Good performance in a froth flotation process is achieved by a combination of, on the one hand, a good separation of the valuable mineral from the gangue by using a selective collector and, on the other hand, the froth characteristics. The froth characteristics include both the amount and the stability of the froth. It is important in the flotation process that the froth collapses as soon as possible after it leaves the flotation cell for the next step in the beneficiation process. A too stable froth will cause both entrainment of particles and froth product pumping problems. Entrainment, especially on a large scale, will result in decreased selectivity (grade, recovery). Problems with froth product pumping will make a process of flotation technically impossible. Collector performance may be improved by using collector combinations of a primary (main) collector and a secondary collector (co-collector). In this document the term "collector composition" shall be used to describe compositions containing both a primary and a secondary collector. For many decades secondary collectors have been used together with primary ionic collectors in salt-type mineral flotation to improve the performance of the primary collector. Nonylphenol ethoxylates have been the dominating nonionic surfactant used as a co-collector in a combination with sarcosine-type primary collectors in selective flotation of apatite from calcite-containing ores. US 4,814,070 discloses the flotation of non-sulfidic ores wherein alkyl sulfosuccinates based on propoxylated and ethoxylated C8-C22 fatty alcohols are employed as a collector. However, nowhere in this document are fatty alcohols having a high degree of branching mentioned nor is it disclosed or suggested that they can be used without the sulfosuccinate function. US 4,789,466 discloses the flotation of apatite ores with a collector composition that contains two components, wherein 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 the primary collector and the alkoxylated fatty alcohol the secondary collector in the apatite ore flotation process. The degree of branching of the used fatty alcohol is either not disclosed or fatty alcohols are applied which are known to have a degree of branching that is 1 or less. US '466 moreover does not disclose mixtures of two alkoxylated alcohols wherein one is relatively highly branched and ethoxylated with 1 to 4 ethylene oxide groups and the other has a higher amount of EO groups than the first alkoxylated alcohol. Nor does this document disclose the use of such mixtures as secondary collector in the flotation of apatite ores or suggest the benefits thereof. SE 409291 discloses a method for foam flotation of calcium phosphate- containing minerals, using an amphoteric surface-active compound as the primary collector. The primary collector's flotating ability may further be strengthened by the presence of a secondary collector, which is described as a polar, water-insoluble, hydrophobic substance having affinity to the mineral particles that have been coated by the primary collector. Examples of the polar components are e.g. water-insoluble soaps, such as calcium soaps, water- insoluble surface-active alkylene oxide adducts, organic phosphate compounds, such as tributyl phosphate, and esters of carbonic acids, such as tributyl ester of nitrilotriacetic acid. In the working examples nonylphenol that has been reacted with two moles of ethylene oxide was used as the secondary collector.

The secondary collector disclosed in SE'291 is still considered a good choice in treating ores, as it provides for an excellent mineral recovery at a P2O₅ grade of higher than 30%. However, due to environmental concerns, an intense search for a replacement of nonylphenol ethoxylates has been ongoing for a long time.

EP 0 270 933 A2 discloses mixtures as collectors for flotation of non-sulfidic ores that contain an alkyl or alkenyl polyethylene glycol ether that is end-capped with a hydrophobic group and an anionic tenside. The end-capped alkyl or alkenyl polyethylene glycol ether in some embodiments is based on a fatty alcohol, preferably a C12 to C18 fatty alcohol. In comparative Examples in EP 0 270 933 also non-end-capped fatty alcohols are used together with anionic tensides. In EP 0 270 933 no disclosure is made of using fatty alcohols having a degree of branching of 1 to 3, and the molecules exemplified in the EP'933 document, though more environmentally friendly than nonylphenol ethoxylates, do not perform as well as these nonylphenol ethoxylates as collectors for flotation of non-sulfidic ores in terms of mineral recovery at the desired high grades.

Thus, there is still a need for secondary collectors having a better environmental profile than nonylphenol ethoxylates that perform equally well. Co-pending patent application PCT appl # EP 2015/071003 discloses the use of a secondary collector, suitable for use with a primary collector of the amphoteric or anionic type, for the froth flotation of non-sulfidic ores to recover oxides, carbonates, phosphates and other salt-type minerals, especially calcium phosphate-containing minerals, in which the secondary collector is a branched fatty alcohol-based compound selected from the group of fatty alcohols with 12- 16 carbon atoms having a degree of branching of 1 -3, and their alkoxylates with a degree of ethoxylation of up to 3.

Summary of the invention It has been found in the present invention that a secondary collector which can be used in combination with a primary collector of the amphoteric or anionic type for the froth flotation of non-sulfidic ores to recover oxides, carbonates, phosphates and other salt-type minerals, especially calcium phosphate- containing minerals, wherein the secondary collector 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 alkoxylates 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) of higher than 3, and carbohydrate-based surfactants, leads to similar good efficiency in recovering apatite in the presence of silicate and/or carbonate minerals as when using a secondary collector only containing compound (i), and to the same good environmental profile especially when compared to nonylphenol ethoxylates, but that additionally compound (ii) has as a benefit that it helps to emulsify compound (i) in the collector composition, enabling compound (i) to be used more efficiently, like in a smaller amount.

Description of the drawings Figure 1 is the distribution of the degree of ethoxylation in a mixture according to the invention

Figure 2 is a schematic flow chart of a flotation procedure

Detailed description of the invention In one aspect, the invention relates to (a secondary collector) mixture 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 carbohydrate-based surfactants and alkoxylates of nonionic hydrocarbon compounds with a degree of ethoxylation of more than 3, such as alkoxylates of hydrocarbon compounds of the group of fatty alcohols, fatty amines, fatty ethanolamides, fatty diethanolamides, fatty acids, triglycerides with a degree of ethoxylation of more than 3, wherein when both compounds (i) and (ii) are ethoxylated alcohols, the mixture has a bimodal degree of ethoxylation distribution.

It should be noted that the mixture of compounds (i) and (ii) - in the embodiments wherein both compounds are ethoxylated alcohol compounds - has a bimodal DE distribution (bimodal meaning a statistical distribution with two maxima). Or in other words, the mixture is not an inherent mixture of more than one molecule that is obtained when a single ethoxylation reaction is performed with a hydrocarbon compound and wherein always some lower and higher ethoxylated molecules are formed and wherein the DE distribution would be unimodal (i.e. have a single 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, preferably the degree of ethoxylation of compound (ii) is higher than that of compound (i). Additionally, the invention relates to the use of the mixture of the above compounds (i) and (ii) as secondary collectors for the froth flotation of non- sulfidic ores, especially to recover calcium phosphate-containing minerals, such as apatite, in combination with a primary collector which is an amphoteric or anionic surfactant and to collector compositions containing such primary and secondary collectors. Examples of other valuable minerals that may be recovered using this combination of primary and secondary collectors include scheelite, fluorspar, calcite and dolomite.

Furthermore, the invention relates to the use of compound (ii) as an emulsifier for compound (i) in a liquid, most prominently a carrier liquid in which a collector composition is present, or alternatively, it relates to a process to emulsify compound (i) in a liquid. This process to emulsify a compound (i) in a liquid contains a step of adding compound (i) to the liquid and a step of adding a compound (ii) to the liquid, wherein the steps may be done one after the other or simultaneously, optionally by premixing compounds (i) and (ii). In a preferred process compounds (i) and (ii) are first mixed and the so obtained mixture is added to the carrier liquid. The carrier liquid for the collector composition is preferably an aqueous liquid.

In preferred mixtures the ratio of compound (i) to compound (ii) on a weight basis 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 "the degree of branching" (DB) as used herein is meant the total number of methyl groups present on the alkyl or alkenyl chain of the alcohol or alkoxylate thereof, minus one. The mean number of methyl groups in the molecules of a sample can easily be determined by NMR spectroscopy. It should be understood that the degree of branching (DB) in the C12-C16 branched fatty alcohol that delivers the branched alkyl or alkenyl chain for compound (i) is an average degree of branching for the fatty alcohol used. Fatty alcohols are oftentimes available or applied as a mixture of several components and therefore DB does not have to be an integer. Consequently, the degree of branching for compound (i) is an average degree of branching, wherein the average degree of branching is the statistical mean of the degree of branching of the molecules of a sample. In a preferred embodiment the DB in compound (i) is higher than 1 , even more preferably it is higher than 1 .5, most preferably higher than 2. In another more preferred embodiment the DB is lower than 3.2, most preferred it is 3 or lower.The molecular formula of the secondary collector compounds (i) and (ii) in a preferred embodiment is R-A (I), wherein for compound (i) R is an alkyl or alkenyl group having 12-16, preferably 12-15, carbon atoms and where said alkyl or alkenyl group has a degree of branching of 1 -3, and wherein for compound (ii) R is any alkyl, aryl or alkenyl group branched or linear having 8-24 carbon atoms; A is selected from the groups

O-(PO)x(EO)y(PO)_zH, for compounds (i) and (ii)

(CO)N(CH₂CH2O(PO)x(EO)_y(PO)_zH)₂, for compound (ii)

(CO)NH(CH₂CH₂O(PO)x(EO)_y(PO)_zH), for compound (ii)

(CO)O((PO)x(EO)y(PO)_zH), for compound (ii) N(PO)x(EO)y(PO)_zH)₂, for compound (ii)

(CO)O((PO)x(EO)_y(PO)_zOCH₂CH(O(PO)x(EO)_y(PO)zO(CO)R)CH₂O((PO)x(EO)_y( PO)zO(CO)R), for compound (ii), and

O(C₆Hi iO5)-(O-(C6Hi iO₅))m, for compound (ii) wherein for compound (i) PO is a propyleneoxy unit and EO is an ethyleneoxy unit; 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 wherein 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 higher than 3 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 of 0 to 5.

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

As is evident from formula (I) for compound (i), the alcohols as such, as well as their alkoxylates, may be used in the secondary collector mixtures.

The alkoxylated products according to formula (I) may be produced by procedures well-known in the art by reacting the appropriate starting alcohol, acid, amide, amine or triglyceride with ethylene oxide, or propylene oxide and ethylene oxide, in the presence of a suitable catalyst, e.g. a conventional basic catalyst, such as KOH, or a so-called narrow range catalyst (see e.g. 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, the alkoxides may be added as blocks in either order, or may be added randomly. The products obtained from reaction with only ethylene oxide are the most preferred.

Preferred compounds (i) are alcohol alkoxylates with a degree of ethoxylation of up to 3. Preferred compounds (ii) are alcohol alkoxylates with a degree of ethoxylation of higher than 3, even more preferred higher than 4. In an 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 of about 0. Carbohydrate-based surfactants, also referred to above as being of the formula R-O-(C6HiiO₅) in a preferred embodiment, are surfactants that are generally nonionic and that in a preferred embodiment contain at least one unit chosen from the group of carbohydrates, such as sorbitol (sorbitans), glucose (glycosides), sucrose and/or their esters, amides.

The primary collectors used in the froth flotation according to the present invention may be either amphoteric or anionic surface-active compounds. Below some examples of formulae for the primary collectors are given, but these should only be considered as suitable for the invention, and are not to be regarded as limiting.

In one embodiment the primary collector for the above-mentioned froth flotation procedure has the formula (II)

wherein Ri is a hydrocarbyl group with 8-22, preferably 12-18, carbon atoms; A is an alkyleneoxy group having 2-4, preferably 2, carbon atoms; p is a number 0 or 1 ; q is a number from 0 to 5, preferably 0; R2 is a hydrocarbyl group having 1 - 4 carbon atoms, preferably 1 , or R₂ is the group

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

The compounds according to formula (II) can easily be produced in high yield from commercially available starting materials using known procedures. US 4,358,368 discloses some ways to produce the compounds where Ri is a hydrocarbyl group with 8-22 carbon atoms (col 6, line 9 - col 7, line 52), and in US 4,828,687 (col 2, line 2 - col 2, line 31 ) compounds where R₂ is

attached to the compound of formula (II) via the methylene group, are described. In another embodiment the primary collector has the formula (III)

wherein R₂ is a hydrocarbyl group with 8-22, preferably 12-18, carbon atoms, D is -CH₂- or -CH₂CH₂- , k is 0-4, preferably 0-3, and most preferably 0-2, and M is hydrogen or a cation, such as sodium or potassium. These products are well known and are produced commercially by methods well known in the art. The products where D is -CH₂- are prepared by the reaction between a fatty amine and chloroacetic acid or its salts, and the products where D is -CH₂CH₂- are prepared by the reaction between a fatty amine and acrylic acid or esters thereof, in the latter case the reaction is followed by hydrolysis. In a further embodiment the primary collector is selected from anionic surface- active compounds such as fatty acids (with a C8 to C24-acyl group), sulfonates, alkyl phosphates, alkyl sulfates and compounds of formula (IV)

where R is a hydrocarbyl group having from 7-23, preferably 1 1 -21 , carbon atoms, optionally substituted; Ri is H or CH₃, preferably H; R₂ is H or a C1 -C4 alkyl group, preferably H; R₃ is H or CH₃, preferably CH₃; n is a number 1 -20; p is a number 1 -3, preferably 1 ; X is H⁺ or a cation which is organic or inorganic, and m represents the valency of the cation and is a number 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 having one or more Ci to C₃ alkyl and/or hydroxyalkyl groups.

For the production of compounds of formula (IV) see the description in WO 2015/000931 (corresponding to PCT/EP2014/064014). Also it is possible to have mixtures of the above compounds as a primary collector. In the case of mixing amphoteric and anionic surface-active compounds as the primary collector, it is preferred to have up to 20 weight % of anionic surfactant on the amount of amphoteric surfactant.

In another aspect, the invention relates to a method for froth flotation of non- sulfidic ores, especially phosphate ores, to recover apatite minerals, in which method the collector mixture described above is used.

Such froth flotation method for phosphate ores may typically comprise the steps of: a) conditioning a pulped ore, wherein the ore comprises 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 the secondary collector described herein, and, optionally, adjusting the pH c) optionally, adding a frother; and d) performing a froth flotation process to recover the phosphate-containing mineral(s).

In yet another aspect the invention pertains to a collector composition comprising a primary collector as defined herein and a secondary collector mixture as defined herein.

The weight ratio between the primary collector and the secondary collector in both the collector compositions and the flotation processes is preferably from 15:85, more preferably 20:80, most preferably 25:75 to 99:1 , preferably 98:2, most preferably 97:3. All weight ratios herein refer to the ratio of active materials, unless stated otherwise.

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

Further flotation aids that may be present in the flotation process are depressants, such as a polysaccharide, alkalized starch or dextrin, extender oils, frothers/froth regulators, such as pine oil, MIBC (methylisobutyl carbinol) and alcohols such as hexanol and alcohol ethoxylates/propoxylates, inorganic dispersants, such as silicate of sodium (water glass) and soda ash, and pH- regulators. The pH during the flotation process will preferably be in the range of 8-1 1 . The present invention is further illustrated by the following examples. EXAMPLES Example 1 General flotation procedure

A phosphate ore containing 20-25% of apatite, 30-40% of silicates and c. 20% of iron oxides was crushed and ground to a desirable flotation size (Κ80=1 10μηη). Three alkoxylates were prepared by reacting the alcohol Exxal 13 (ex Exxon), which has a DB of 3, with ethylene oxide in an amount of 1 .5, 5 and 8.5 equivalents, respectively, on the molar amount of the alcohol.

500 g of the ore were placed in a 1 .4L Denver flotation cell, 500 ml of process water (25mg/l Ca²⁺, 40mg/l Mg²⁺) were added and the mixing was started. Then 5 minutes conditioning with 1000g/t of a 1 %(w/w) aqueous starch solution was performed, the collector (600g/t (or a mixture of primary acylglycide collector and secondary collectors)) was added to the flotation cell as a 1 % aqueous solution and conditioning was continued for 2.5 minutes. After the conditioning steps tap water was added so that a total volume of 1 .4L was obtained, the pH of the flotation mixture was adjusted to 9.5 with a 10% NaOH aqueous solution and the flotation was started. The experiment was performed at RT (20±1 °C). The rougher flotation, followed by three cleaning steps, was performed. All fractions (tailings, middlings and concentrate) were collected and analysed. Reference is made to Figure 2 for the general procedure that was followed.

The flotation results and the composition of the collector formulation used are displayed in Table 1 . Table 1 . Flotation results presented as P2O₅ recovery and grade.

Amount of Average degree Amount of 2^na cleaner concentrate 3^ra cleaner concentrate alcohol+XEO, g/t of ethoxylation acylglycide,

1.5EO 5EO 8.5EO g/t Recovery, % Grade, % Recovery, % Grade, %

Comparison 0 0 0 0 600 82.8 32.7 78.6 34.1 1

Invention 150 0 150 5 300 81.6 33.2 79.5 34.2

Comparison 0 300 0 5 300 76.6 33.4 72.4 35.0

As one can see from Table 1 , the flotation results can be improved only if use is made of the mixture of two nonionic surfactants as a secondary collector . In Figure 1 the distribution of the degree of ethoxylation for the formulation according to the invention and the comparison 2 formulation are graphically represented. The results clearly show that the double peak distribution plays a crucial role in the flotation. In a combination with the primary collector the mixture of two ethoxylated alcohols with a degree of ethoxylation equal to 1 .5 and 8.5, respectively, provides much better recovery than the single ethoxylated alcohol with a degree of ethoxylation equal to 5.

Example 2

The emulsion formation and stability were tested by preparing aqueous 5 w% solutions as follows: five (5) g of the surfactant or surfactant mixture were added to 150 ml beaker, diluted with 95 g of water and vigorously mixed. After 5 min the mixing was stopped. Visual observation of the prepared solutions was done after 1 , 2, 3, 4, 5, 10 and 60 min.

The results are given in Table 2 below. Table 2 Emulsion formation and stability results of mixture of the two alcohol ethoxylates

Em means emulsion, 2p means 2 phases

From Table 2 it is clear that adding a compound having a degree of ethoxylation of higher than 3 to an alcohol ethoxylate that only has a degree of ethoxylation of 1 .5 helps considerably to form an emulsion. Adding more of the higher ethoxylated product such as up to 50 wt% makes the emulsion much more stable.

Claims

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 alkoxylates 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 of higher than 3 and carbohydrate-based surfactants, wherein if both compounds (i) and (ii) are ethoxylated alcohols, the mixture has a bimodal degree of ethoxylation distribution.

Mixture of claim 1 wherein 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 of more than 3; and carbohydrate-based surfactants.

Mixture according to claim 1 or 2 where the molecular formula of compounds (i) and (ii) is formula (I)

R-A (I)

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

O-(PO)x(EO)_y(PO)_zH, for compounds (i) and (ii)

(CO)N(CH₂CH2O(PO)x(EO)_y(PO)_zH)₂, for compound (ii)

(CO)NH(CH₂CH₂O(PO)x(EO)_y(PO)_zH), for compound (ii)

(CO)O((PO)x(EO)_y(PO)_zH), for compound (ii)

N(PO)x(EO)_y(PO)_zH)₂, for compound (ii)

(CO)O((PO)x(EO)_y(PO)_zOCH₂CH(O(PO)x(EO)y(PO)_zO(CO)R)CH₂O ((PO)x(EO)y(PO)_zO(CO)R), for compound (ii), and

0(C₆Hi i05)-(0-(C6Hii0₅))m, for compound (ii)

wherein 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 higher than 3 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 of 0 to 5.

4. Mixture of any one of claims 1 to 3 additionally containing a liquid wherein compound (ii) is an emulsifier for compound (i) in the liquid

5. Use of the mixture according to any one of claims 1 to 4 as secondary collectors for the froth flotation of non-sulfidic ores, in combination with a primary collector selected from the group of amphoteric and anionic surface-active compounds.

6. Use according to claim 5 wherein said primary collector is an amphoteric surface-active compound selected from the group consisting of compounds having the formula (II)

wherein Ri is a hydrocarbyl group with 8-22, preferably 12-18, carbon atoms; A is an alkyleneoxy group having 2-4 carbon atoms; p is a number 0 or 1 ; q is a number from 0 to 5, preferably 0, F¾ is a hydrocarbyl group having 1 -4 carbon atoms, preferably 1 , or R₂ is the group

wherein Ri, A, p and q have the same meaning as above, Y^" is selected from the group consisting of COO^" and SO3^", preferably COO^"; n is a number 1 or 2, preferably 1 ; M is a cation which may be monovalent or divalent and inorganic or organic, and r is a number 1 or 2; or where compound (II) is in its acidic protonated form without an external cation (M^r+) 1/r; and compounds having the formula (III)

wherein R₂ is a hydrocarbyl group with 8-22, preferably 12-18, carbon atoms, D is -CH₂- or -CH₂CH₂- , k is 0-4, preferably 0-3, and most preferably 0-2, and M is hydrogen or a cation, such as sodium or potassium, and anionic surface-active compound selected from the group consisting of fatty acids, sulfonates, alkyi phosphates, alkyi sulfates and compounds of formula (IV)

wherein R is a hydrocarbyl group having from 7-23, preferably 1 1 -21 , carbon atoms, optionally substituted; Ri is H or CH₃, preferably H; R₂ is H or a C1 -C4 alkyl group, preferably H; R₃ is H or CH₃, preferably CH₃; n is a number 1 -20; p is a number 1 -3, preferably 1 ; X is H⁺ or a cation which is organic or inorganic, and m represents the valency of the cation and is a number 1 -2, preferably 1 , and mixtures thereof.

7. Use according to any one of the preceding claims 5 or 6 wherein the weight ratio between the primary collector and the secondary collector is between 15:85 and 99:1 .

8. Use according to any one of the preceding claims 5 to 7 wherein the non- sulfidic ore is a calcium phosphate-containing ore. 9. A process for the froth flotation of non-sulfidic ores using a collector composition comprising a primary collector selected from the group of amphoteric and anionic surface-active compounds and a secondary collector that contains the mixture according to any one of claims 1 to 4. 10. A process according to claim 9 which comprises the steps of

i) conditioning a pulped non-sulfidic ore, wherein the ore comprises a phosphate-containing mineral, and gangue minerals with the collector composition and optionally other flotation aids, and

ii) performing a froth flotation process to recover the phosphate- containing mineral(s).

1 1. A process according to claim 9 or 10 wherein said primary collector is an amphoteric surface-active compound selected from the group consisting of compounds having the formula (II)

wherein Ri is a hydrocarbyl group with 8-22, preferably 12-18, carbon atoms; A is an alkyleneoxy group having 2-4 carbon atoms; p is a number 0 or 1 ; q is a number from 0 to 5, preferably 0; R₂ is a hydrocarbyl group having 1 -4 carbon atoms, preferably 1 , or R₂ is the group

wherein Ri, A, p and q have the same meaning as above, Y^" is selected from the group consisting of COO^" and SO3^", preferably COO^"; n is a number 1 or 2, preferably 1 ; M is a cation which may be monovalent or divalent and inorganic or organic, and r is a number 1 or 2; or where compound (II) is in its acidic protonated form without an external cation (M^r+) 1/r; and compounds of formula (III)

wherein R₂ is a hydrocarbyl group with 8-22, preferably 12-18, carbon atoms, D is -CH₂- or -CH₂CH₂- , k is 0-4, preferably 0-3, and most preferably 0-2, and M is hydrogen or a cation, such as sodium or potassium; or an anionic surface-active compound selected from the group consisting of fatty acids, sulfonates, alkyi phosphates, alkyi sulfates and compounds of formula (IV)

wherein R is a hydrocarbyl group having from 7-23, preferably 1 1 -21 , carbon atoms, optionally substituted; Ri is H or CH₃, preferably H; R₂ is H or a C1 -C4 alkyi group, preferably H; R₃ is H or CH₃, preferably CH₃; n is a number 1 -20; p is a number 1 -3, preferably 1 ; X is H⁺ or a cation which is organic or inorganic, and m represents the valency of the cation and is a number 1 -2, preferably 1 ; and mixtures thereof.

12. A process according to any one of claims 9 to 1 1 wherein the weight ratio between the primary collector and the secondary collector is from 15:85 to 99:1 .

13. A collector composition comprising a surface-active primary collector selected from the group consisting of fatty acids, sulfonates, alkyi phosphates, alkyi sulfates, compounds of formula (II)

wherein Ri , A, p and q have the same meaning as above, Y^" is selected from the group consisting of COO^" and SO3^", preferably COO^"; n is a number 1 or 2, preferably 1 ; M is a cation which may be monovalent or divalent and inorganic or organic, and r is a number 1 or 2; or where compound (II) is in its acidic protonated form without an external cation (M^r+) 1/r; compounds of formula (III)

wherein R₂ is a hydrocarbyl group with 8-22, preferably 12-18, carbon atoms, D is -CH₂- or -CH₂CH₂- , k is 0-4, preferably 0-3, and most preferably 0-2, and M is hydrogen or a cation, such as sodium or potassium;

and compounds of formula (IV)

wherein R is a hydrocarbyl group having from 7-23, preferably 1 1 -21 , carbon atoms, optionally substituted; Ri is H or CH₃, preferably H; R₂ is H or a C1 -C4 alkyl group, preferably H; R₃ is H or CH₃, preferably CH₃; n is a number 1 -20; p is a number 1 -3, preferably 1 ; X is H⁺ or a cation which is organic or inorganic, and m represents the valency of the cation and is a number 1 -2, preferably 1 ; and mixtures thereof; and a secondary collector that contains the mixtures according to one of claims 1 to 4.

14. A composition according to claim 13 wherein the weight ratio between the primary collector and the secondary collector is between 15:85 and 99:1 .

15. Process to emulsify a compound (i) in a liquid wherein the process contains a step of adding compound (i) to the liquid and a step of adding a compound (ii) to the liquid, wherein the steps may be done one after the other or simultaneously, optionally by premixing compounds (i) and (ii), wherein compounds (i) and (ii) are as defined in any one of claims 1 to 3.