METHOD FOR FLOTATION OF A SILICATE-CONTAINING IRON ORE

Abstract

The invention relates to a method for manufacturing a concentrate enriched in iron mineral content from an ore, which contains an iron mineral and silicate, by a reverse flotation, which method comprises the step of (c) adding a collector composition comprising (i) an amidoamine, which contains a compound of formula I

##STR00001## or a salt of a protonated compound of formula I and an anion; (ii) an ethoxylate, which contains a compound of formula II

R.sup.EO(CH.sub.2CH.sub.2O).sub.nH(II), wherein R.sup.E is a linear or mono-branched aliphatic C.sub.10-C.sub.20 alkyl or a linear aliphatic C.sub.10-C.sub.20 alkenyl, and n is an integer from 1 to 12,
to a prepared aqueous pulp of the ore and optionally one or more flotation auxiliary to obtain an aqueous mixture. Furthermore, the use of the collector composition as a flotation collector is described and the collector composition itself

Claims

1. A method for manufacturing a concentrate enriched in iron mineral content from an ore, which contains an iron mineral and silicate, by a reverse flotation, characterized that said method comprises the step of (c) adding a collector composition comprising (i) an amidoamine, which contains a compound of formula I ##STR00030## wherein R.sup.1 is a linear or branched aliphatic C.sub.7-C.sub.19 alkyl or a linear C.sub.7-C.sub.19 aliphatic alkenyl, R.sup.2 is a linear or branched aliphatic C.sub.2-C.sub.6 alkylene, R.sup.3 and R.sup.4 are independently from each other H, C.sub.1-C.sub.2 alkyl or a substituent of formula I-S
*-[(CH.sub.2).sub.pNH].sub.q(CH.sub.2).sub.pNH.sub.2(I-S) wherein p is 2, 3 or 4, q is 0, 1, 2 or 3, and * represents the connecting site of the substituent, or a salt of a protonated compound of formula I and an anion; (ii) an ethoxylate, which contains a compound of formula II
R.sup.EO(CH.sub.2CH.sub.2O).sub.nH(II), wherein R.sup.E is a linear or mono-branched aliphatic C.sub.10-C.sub.20 alkyl or a linear aliphatic C.sub.10-C.sub.20 alkenyl, n is an integer from 1 to 12, to a prepared aqueous pulp of the ore and optionally one or more flotation auxiliary to obtain an aqueous mixture.

2. The method according to claim 1, wherein the method comprises the steps of (a) providing the ore, which contains an iron mineral and silicate, (b) preparing from the provided ore by addition of water and optionally one or more flotation auxiliaries an aqueous pulp, (c) adding the collector composition to the prepared aqueous pulp of the ore and optionally one or more flotation auxiliaries to obtain an aqueous mixture, (d) aerating the aqueous mixture in a flotation cell to generate a froth, which is enriched in silicate content, and removing the generated froth from the flotation cell, (e) obtaining from the flotation cell the concentrate enriched in iron mineral content.

3. The method according to claim 1, wherein (i) the amidoamine contains different compounds of formula I, or salts of the protonated different compounds of formula I and an anion; (ii) the ethoxylate contains different compounds of formula II.

4. The method according to claim 1 wherein the amidoamine is obtainable by condensation of a fatty acid of formula I-FA with an amine of formula I-A ##STR00031## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and formula I-S, p, q and * are defined as in claim claim 1.

5. The method according to claim 1, wherein (ii) the ethoxylate is obtainable by ethoxylation of one equivalent of an alcohol of the formula II-AL
R.sup.EOH(II-AL), wherein R.sup.E is defined as in claim 1, with n equivalents of ethylene oxide, wherein n is defined as in claim 1.

6. The method according to claim 1, wherein the collector composition comprises (i) an amidoamine, which contains a compound of formula I ##STR00032## wherein R.sup.1 is a linear or branched aliphatic C.sub.11-C.sub.19 alkyl or a linear C.sub.11-C.sub.19 aliphatic alkenyl, R.sup.2 is a linear or branched aliphatic C.sub.2-C.sub.6 alkylene, R.sup.3 and R.sup.4 are independently from each other H, C.sub.1-C.sub.2 alkyl or a substituent of formula I-S
*-[(CH.sub.2).sub.pNH].sub.q(CH.sub.2).sub.pNH.sub.2(I-S) wherein p is 2, 3 or 4, q is 0, 1, 2 or 3, and * represents the connecting site of the substituent, or a salt of a protonated compound of formula I and an anion, and which is obtainable by condensation of a fatty acid of formula I-FA with an amine of formula I-A ##STR00033## (ii) an ethoxylate, which contains a compound of formula II
R.sup.EO(CH.sub.2CH.sub.2O).sub.nH(II) wherein R.sup.E is a linear or mono-branched aliphatic C.sub.10-C.sub.20 alkyl or a linear aliphatic C.sub.10-C.sub.20 alkenyl, n is an integer from 1 to 12, and which is obtainable by ethoxylation of one equivalent of an alcohol of formula II-AL
R.sup.EOH(II-AL) with n equivalents of ethylene oxide.

7. The method according to claim 1, wherein the collector composition comprises more parts by weight of the amidoamine than of the ethoxylate, and the sum of the amidoamine and the ethoxylate is 100 parts by weight.

8. The method according to claim 1 wherein the collector composition comprises (i) 65 to 99 parts by weight of the amidoamine, and (ii) 1 to 35 parts by weight of the ethoxylate, and the sum of the amidoamine and the ethoxylate is 100 parts by weight.

9. The method according to claim 1, wherein the collector composition comprises (i) 75 to 99 parts by weight of the amidoamine, and (ii) 1 to 25 parts by weight of the ethoxylate, and the sum of the amidoamine and the ethoxylate is 100 parts by weight.

10. The method according to claim 1 wherein the collector composition comprises (i) 85 to 99 parts by weight of the amidoamine, and (ii) 1 to 15 parts by weight of the ethoxylate, and the sum of the amidoamine and the ethoxylate is 100 parts by weight.

11. The method according to claim 1, wherein (a) R.sup.3 is H or C.sub.1-C.sub.2 alkyl, (b) p is 2 and q is 1, 2 or 3, (c) n is 1, 2, 3 or 4, (d) R.sup.E is a linear or mono-branched aliphatic C.sub.12-C.sub.18 alkyl or a linear aliphatic C.sub.18 alkenyl or any combination of (a) to (d).

12. (canceled)

13. (canceled)

14. (canceled)

15. The method according to claim 1, wherein in case the ethoxylate contains only compounds of formula II with the same RE, the same RE is linear, or in case the ethoxylate contains compounds of formula II with two or more different RE, an average degree of branching of RE for all the compounds of formula II is between 0 and 0.8.

16. The method according to claim 15, wherein R.sup.E is linear.

17. The method according to claim 1, wherein the anion is C.sub.1-C.sub.18 carboxylate, fluoride, chloride, bromide, iodide, sulfonate, hydrogensulfate, sulfate, dihydrogenphosphate, hydrogenphosphate, phosphate, nitrate, hydrofluorosilicate or fluorosilicate.

18. The method according to claim 1, wherein the collector composition is added in an amount between 10 g to 500 g per ton of the ore.

19. The method according to claim 1, wherein the pH value at step (c) is between 8 and 12.

20. The method according to claim 1, wherein the collector composition is added as an aqueous solution or suspension.

21. The method according to any preceding claim 1, wherein at step (b) one or more flotation auxiliary is added and one of the flotation auxiliary is a depressing agent, a froth regulator, a co-collector or an extender oil.

22. The method according to claim 21, wherein a depressing agent, which is starch, is added.

23. (canceled)

24. A collector composition, comprising (i) an amidoamine, which contains a compound of formula I ##STR00034## wherein R.sup.1 is a linear or branched aliphatic C.sub.7-C.sub.19 alkyl or a linear C.sub.7-C.sub.19 aliphatic alkenyl, R.sup.2 is a linear or branched aliphatic C.sub.2-C.sub.6 alkylene, R.sup.3 and R.sup.4 are independently from each other H, C.sub.1-C.sub.2 alkyl or a substituent of formula I-S
*-[(CH.sub.2).sub.pNH].sub.q(CH.sub.2).sub.pNH.sub.2(I-S) wherein p is 2, 3 or 4, q is 0, 1, 2 or 3, and * represents the connecting site of the substituent, or a salt of a protonated compound of formula I and an anion; (ii) an ethoxylate, which contains a compound of formula II
R.sup.EO(CH.sub.2CH.sub.2O).sub.nH(II) wherein R.sup.E is a linear or mono-branched aliphatic C.sub.10-C.sub.20 alkyl or a linear aliphatic C.sub.10-C.sub.20 alkenyl, and n is an integer from 1 to 12.

Description

[0183] A further embodiment of the invention is a use of a collector composition comprising [0184] (i) an amidoamine, which contains a compound of formula I

##STR00024## [0185] wherein [0186] R.sup.1 is a linear or branched aliphatic C.sub.7-C.sub.19 alkyl or a linear C.sub.7-C.sub.19 aliphatic alkenyl, [0187] R.sup.2 is a linear or branched aliphatic C.sub.2-C.sub.6 alkylene, [0188] R.sup.3 and R.sup.4 are independently from each other H, C.sub.1-C.sub.2 alkyl or a substituent of formula I-S

*-[(CH.sub.2).sub.pNH].sub.q(CH.sub.2).sub.pNH.sub.2(I-S), [0189] wherein [0190] p is 2, 3 or 4, [0191] q is 0, 1, 2 or 3, and [0192] * represents the connecting site of the substituent, or [0193] a salt of a protonated compound of formula I and an anion; [0194] (ii) an ethoxylate, which contains a compound of formula II

R.sup.EO(CH.sub.2CH.sub.2O).sub.nH(II), [0195] wherein [0196] R.sup.E is a linear or mono-branched aliphatic C.sub.10-C.sub.20 alkyl or a linear aliphatic C.sub.10-C.sub.20 alkenyl, [0197] n is an integer from 1 to 12,
as a flotation collector for manufacturing a concentrate enriched in iron mineral content from an ore, which contains an iron mineral and silicate, by a reverse flotation.

[0198] A further embodiment of the invention is a collector composition comprising [0199] (i) an amidoamine, which contains a compound of formula I

##STR00025## [0200] wherein [0201] R.sup.1 is a linear or branched aliphatic C.sub.7-C.sub.19 alkyl or a linear C.sub.7-C.sub.19 aliphatic alkenyl, [0202] R.sup.2 is a linear or branched aliphatic C.sub.2-C.sub.6 alkylene, [0203] R.sup.3 and R.sup.4 are independently from each other H, C.sub.1-C.sub.2 alkyl or a substituent of formula I-S

*-[(CH.sub.2).sub.pNH].sub.q(CH.sub.2).sub.pNH.sub.2(I-S), [0204] wherein [0205] p is 2, 3 or 4, [0206] q is 0, 1, 2 or 3, and [0207] * represents the connecting site of the substituent, or [0208] a salt of a protonated compound of formula I and an anion; [0209] (ii) an ethoxylate, which contains a compound of formula II

R.sup.EO(CH.sub.2CH.sub.2O).sub.nH(II) [0210] wherein [0211] R.sup.E is a linear or mono-branched aliphatic C.sub.10-C.sub.20 alkyl or a linear aliphatic C.sub.10-C.sub.20 alkenyl, and [0212] n is an integer from 1 to 12.

[0213] Preferably, the collector composition is part of an aqueous solution or suspension, which contains the collector composition and water.

[0214] The following examples illustrate further the invention without limiting it. Percentage values are percentage by weight if not stated differently.

[0215] A) amidoamine Collector

[0216] SOFA-1 is a distilled soy oil fatty acid grade with a specification of 0.1 wt. % saturated C.sub.14 carboxylic acid (e.g. tetradecanoic acid), 10-23 wt. % saturated C.sub.16 carboxylic acid (e.g. palmitic acid), 2-8 wt. % saturated C.sub.18 carboxylic acid (e.g. stearic acid), 24-34 wt. % mono-unsaturated C.sub.18 carboxylic acid (e.g. oleic acid), 38-50 wt. % di-unsaturated C.sub.18 carboxylic acid (e.g. linoleic acid) and 2-8 wt. % tri-unsaturated C.sub.18 carboxylic acid (e.g. linolenic acid).

[0217] A-1: Reaction Product of Soy Oil Fatty Acid and N,N-dimethylpropane-1,3-diamine (101)

##STR00026##

[0218] A stirred solution of distilled soy oil fatty acid (410 g SOFA-1, 1.5 mol, represented by R.sup.A1C(O)OH in the reaction scheme) is heated to 40 C. and N,N-dimethylpropane-1,3-diamine (199 g, 1.95 mol; molar ratio of R.sup.A1C(O)OH to N,N-dimethylpropane-1,3-diamine is 1 to 1.3) is added in 5 minutes. The addition causes an exothermic reaction due to a salt formation. After complete addition, the reaction mixture is quickly heated until 80 C. and then heated slowly until 150 C. in 1.5 hours. The mixture is kept at reflux at 150 C. for 1 hour. Afterwards, water is distilled. Then, the reaction temperature is slowly raised until 180 C. and is kept at this temperature for one hour. The acidic index is measured by titration with KOH solution (0.05 mol/L) to identify the end of the reaction by using 50 mL neutralized ethanol as solvent and phenolphthalein as indicator. After all the fatty acid is consumed as determined by a measured acidic index of 0 mg KOH/g, the mixture is cooled to 50 C. The reaction product (101) is obtained as a yellow brownish solid in a yield of 91%.

[0219] FT-IR v.sub.max (liquid film) main bands [cm.sup.1]: 3292.2, 3083.6, 2926.3, 2855.7, 1648.8, 1559, 1462.7

[0220] .sup.13C NMR (126 MHz, Chloroform-d): 173.04 (C-6), 130.19 (double bonds), 130.03 (double bonds), 129.97 (double bonds), 129.74 (double bonds), 128.05 (double bonds), 127.92 (double bonds), 58.60 (C-2), 45.39 (C-10, C-11), 39.19 (C-4), 36.95 (C-7), 31.93, 31.91, 31.53, 29.78, 29.75, 29.70, 29.67, 29.65, 29.53, 29.43, 29.36, 29.33, 29.18, 27.22 (C-21, C-24), 26.28 (C-3), 25.79 (C-34), 25.64, 22.69, 22.58, 14.11 (C-13).

[0221] A-2: Reaction Product of Soy Oil Fatty Acid and 1,3-diaminopropane (102)

##STR00027##

[0222] A stirred solution of distilled soy oil fatty acid (410 g SOFA-1, 1.5 mol, represented by R.sup.A1-C(O)OH in the reaction scheme) is heated to 40 C. and 1,3-diaminopropane (144 g, 1.95 mol; molar ratio of R.sup.A1-C(O)OH to 1,3-diaminopropane is 1 to 1.3) is added in 5 minutes. The addition causes an exothermic reaction due to a salt formation. After complete addition, the reaction mixture is quickly heated until 80 C. and then heated slowly until 180 C. in 1.5 hours. The mixture is kept at reflux at 180 C. for 2.5 hours. Afterwards, water is distilled. Then, the reaction mixture is kept under vacuum for one hour. The acidic index is measured by titration with KOH solution (0.05 mol/L) to identify the end of the reaction by using 50 mL neutralized ethanol as solvent and phenolphthalein as indicator. After all the fatty acid is consumed as determined by a measured acidic index of 0 mg KOH/g, the mixture is cooled to 50 C. The reaction product (102) is obtained as a yellow brownish solid. In the reaction scheme, N-(3-aminopropyl)amide derivatives are depicted. It is assumed that due to a further intramolecular condensation reaction, the reaction product contains also 2-R.sup.A1-1,4,5,6-tetrahydropyrimidine derivatives.

[0223] .sup.1H NMR (400.33 MHz, Chloroform-d): 6.28 (double bonds), 5.93 (double bonds), 5.65 (double bonds), 5.33 (double bonds), 3.31 (C12, C14), 3.25 (C5), 2.76 (CH.sub.2 besides CC), 2.15 (CH.sub.2 besides CO), 2.01 (CH.sub.2 besides CO), 1.77 (C6, C13), 1.59, 1.28, 0.88 (CH.sub.3 aliphatic chain).

[0224] A-3: Reaction Product of Soy Oil Fatty Acid and 1,3-diaminopentane

##STR00028##

[0225] A stirred solution of distilled soy oil fatty acid (410 g SOFA-1, 1.5 mol, represented by R.sup.A1C(O)OH in the reaction scheme) is heated to 40 C. and 1,3-diaminopentane (199 g, 1.95 mol; molar ratio of R.sup.A1C(O)OH to 1,3-diaminopentane is 1 to 1.3) is added in 5 minutes. The addition causes an exothermic reaction due to a salt formation. After complete addition, the reaction mixture is quickly heated until 80 C. and then slowly heated until 150 C. in 1.5 hours. The mixture is kept at reflux at 150 C. for one hour. Afterwards, water is distilled. Then, the reaction temperature is slowly raised until 180 C. and kept at this temperature for 2.5 hours. The acidic index is measured by titration with KOH solution (0.05 mol/L) to identify the end of the reaction by using 50 mL neutralized ethanol as solvent and phenolphthalein as indicator. After all the fatty acid is consumed as determined by a measured acidic index of 0 mg KOH/g, the mixture is cooled to 50 C. The reaction product is obtained as a yellow brownish solid. In the reaction scheme above, expected N-(3-aminopentyl)amide derivatives (103) are depicted. It is assumed that the reaction product contains also N-(3-amino-1-ethyl-propyl)amide derivatives. It is further assumed that due to a further intramolecular condensation reaction, the reaction product contains also 2-R.sup.A1-4-ethyl-1,4,5,6-tetrahydropyrimidine derivatives or 2-R.sup.A1-6-ethyl-1,4,5,6-tetrahydro-pyrimidine derivatives. However, as the expected N-(3-aminopentyl)amide derivatives (103) is not identifiable in the .sup.1H NMR data shown below, example A-3 is disregarded.

[0226] .sup.1H NMR (400.33 MHz, Chloroform-d): 6.28 (double bonds), 5.93 (double bonds), 5.66 (double bonds), 5.33 (double bonds), 3.36 (C-8), 3.30 (C-3), 2.76 (CH.sub.2 besides CC), 2.38, 2.14, 2.04, 1.99, 1.73, 1.61, 1.45, 1.25, 0.96 (C-9, CH.sub.3 aliphatic chain), 0.88 (CH.sub.3 aliphatic chain).

[0227] A-4: Reaction Product of Soy Oil Fatty Acid and Diethylenetriamine (104)

##STR00029##

[0228] A stirred solution of distilled soy oil fatty acid (410 g SOFA-1, 1.5 mol, represented by R.sup.A1C(O)OH in the reaction scheme) is heated to 40 C. and diethylenetriamine (155 g, 1.5 mol; molar ratio of R.sup.A1C(O)OH to diethylenetriamine is 1 to 1) is added in 5 minutes. The addition causes an exothermic reaction due to a salt formation. After complete addition, the reaction mixture is heated until 80 C. automatically, and then heated slowly until 180 C. in 1.5 hours. The mixture is kept at reflux at 180 C. for two hours and water is distilled. Then, the reaction mixture is kept under vacuum (700 mm Hg respectively 93 kPa below atmospheric pressure) for one hour. The acidic index is measured by titration with KOH solution (0.05 mol/L) to identify the end of the reaction by using 50 mL neutralized ethanol as solvent and phenolphthalein as indicator. After all the fatty acid is consumed as determined by a measured acidic index of 0 mg KOH/g, the mixture is cooled to 50 C. The reaction product (104) is obtained as a yellow brownish solid. In the reaction scheme, N-[2-(2-aminoethylamino)ethyl]amide derivatives are depicted. It is assumed that due to a further intramolecular condensation reaction, the reaction product contains also 2-(2-R.sup.A1-4,5-dihydroimidazol-1-yl)ethanamine derivatives.

[0229] .sup.1H NMR (400.33 MHz, Chloroform-d): 6.86 (double bonds), 6.25 (double bonds), 6.01 (double bonds), 5.35 (double bonds), 3.68 (C21), 3.39 (C4, C20), 3.28, 3.19 (C8, C11, C15), 3.12, 2.84 (C12, C14), 2.77 (C5, C7 +CH.sub.2 besides CC), 2.17 (C23, C24), 2.04 (CH.sub.2 besides CO), 1.62 (CH.sub.2-chain), 1.31 (CH.sub.2-chain), 1.25 (CH.sub.2-chain), 0.97 (CH.sub.3 aliphatic chain), 0.88 (CH.sub.3 aliphatic chain).

[0230] B) Non-Ionic Collector

[0231] B-1: C13-C15 oxo-alcohol 3EO (201) (for Inventive Example)

[0232] 50% aqueous KOH (3.9 g) are added to C.sub.13-C.sub.15 oxo-alcohol (535 g=2.5 mol, primary alcohol, C.sub.13 to C.sub.15 molar ratio around 1, linear compounds and mono-branched compounds, average degree of branching around 0.6) and water is removed at 100 C. and 20 mbar over 2 h. The mixture is transferred into a 5 L reactor which is flushed three times with nitrogen and heated to 130 C. under 2 bar pressure. Ethylene oxide (330 g=7.5 mol) is added as follows: 80 g are injected over the first 15 min and the rest over 4 h. The reaction mixture is stirred over 2 h at 130 C., then cooled to ambient temperature. The catalyst is neutralized with acetic acid (2.1 g). The obtained product (201) is used without further purification.

[0233] B-2: C.sub.16-C.sub.18:1 Linear Alcohol 2EO (202) (for Inventive Example)

[0234] 50% aqueous KOH (3.9 g) are added to a distilled tallow oleic alcohol (665 g=2.5 mol, tallow oleic alcohol is based on a natural raw material, the molar ratio between cetyl alcohol [hexadecane-1-ol, 242.4 g/mol] and oleyl alcohol [(Z)-octadec-9-en-1-ol, 268.5 g/mol] is 10 cetyl alcohol to 90 oleyl alcohol based on 100 for the molar sum of all cetyl alcohol and all oleyl alcohol [average molecular weight 265.9 g/mol], the amount of ethylene oxide has accordingly to be adjusted for a respective ratio of equivalents of ethylene oxide to one equivalent of hydroxy group of the alcohol) and water is removed at 100 C. and 20 mbar over 2 h. The mixture is transferred into a 5 L reactor which is flushed three times with nitrogen and heated to 130 C. under 2 bar pressure. Ethylene oxide (220 g=5 mol) is added as follows: 80 g were injected over the first 15 min and the rest over 4 h. The reaction mixture is stirred over 2 h at 130 C., then cooled to ambient temperature. The catalyst is neutralized with acetic acid (2.1 g). The obtained product (202) is used without further purification.

[0235] B-3: iso-C.sub.13 oxo-alcohol 3 EO (203) (for Comparative Example)

[0236] 50% aqueous KOH (3.9 g) are added to iso-tridecanol (500 g=2.5 mol, primary iso-C13 oxo-alcohol, which is obtained from trimerization of butene followed by hydroformylation, double-branched compounds and triple-branched compounds, average degree of branching between 2.0 and 2.5) and water is removed at 100 C. and 20 mbar over 2 h. The mixture is transferred into a 5 L reactor which is flushed three times with nitrogen and heated to 130 C. under 2 bar pressure. Ethylene oxide (330 g=7.5 mol) is added as follows: 80 g are injected over the first 15 min and the rest over 4 h. The reaction mixture is stirred over 2 h at 130 C., then cooled to ambient temperature. The catalyst is neutralized with acetic acid (2.1 g). The obtained product (203) is used without further purification.

[0237] C) Flotation Auxiliary

[0238] St-1: Causticized Starch

[0239] 4 g corn starch and 50 g of distilled water are added in a 600 mL beaker. 1 g of an aqueous 50 wt. % NaOH solution is added and energetically mixed for 10 minutes until it acquires a gel appearance. 345 g of distilled water are added to the mixture and a homogenization is made with a magnetic stirrer for 5 minutes to obtain a solution of causticized starch St-1.

[0240] D) Collector Solution

[0241] An aqueous collector solution is prepared by dissolving an amidoamine, i.e. the obtained reaction product, and optionally a non-ionic collector, i.e. the obtained reaction product, in a relative weight ratio, as stated in table D-1 in water in an amount to obtain a 1 wt. % aqueous collector solution.

TABLE-US-00001 TABLE D-1 collector amidoamine non-ionic solution No. collector amount .sup.c) collector amount .sup.c) D-1-1 .sup.a) (101) 100 D-1-2 .sup.b) (101) 90 (201) 10 D-1-3 .sup.a) (102) 100 D-1-4 .sup.b) (102) 90 (201) 10 D-1-5 .sup.b) (102) 98 (202) 2 D-1-6 .sup.a) (104) 100 D-1-7 .sup.b) (104) 90 (201) 10 D-1-8 .sup.b) (104) 98 (202) 2 D-1-9 .sup.a) (104) 90 (203) 10 Footnote: .sup.a) comparative .sup.b) inventive .sup.c) parts by weight based on 100 parts by weight of the sum of the amidoamine and if present of the non-ionic collector

[0242] E) Calculation of Selectivity

[0243] A measure of selectivity for the valuable mineral and against the gangue can be Separation Efficiency (SE) defined as SE=Rv-RG, with Rv being recovery of the valuable element and RG being the recovery of gangue as described in Separation Efficiency by Norman F. Schulz, Society of Mining Engineers of AIME, pre-print No. 69-B-44, paper to be presented at the Annual Meeting of the American Institute of Mining, Metallurgical and Petroleum Engineers, Washington, D.C., 1969 (available in digitalized form for example at www.911metallurgist.com/separation-efficiency/). The same calculation can be made from element assays of the concentrate and tailings fraction and represented as

[00001]$SE=100\frac{c_m}{f}\left[\frac{\left(f-t\right)\left(c-f\right)}{\left(c-t\right)\left(c_m-f\right)}\right]=100\frac{f-t}{c-t}\left[\frac{c}{f}-\frac{c_m-c}{c_m-f}\right]$

where [0244] c: atom content of desired element [wt. %] in the concentrate [0245] cm: atom content of desired element [wt. %] in the mineral being concentrated [0246] f: atom content of desired element [wt. %] in the feed [0247] t: atom content of desired element [wt. %] in the tailings

[0248] The value of Separation Efficiency for an ideal separation is 100, however the real values are below that. The closer it is to 100, the better the separation and the recovery of valuable element.

[0249] In case of itabirite ore, the desired element is iron (Fe) and the mineral being concentrated is haematite Fe.sub.2O.sub.3 with an atom content of iron in the mineral of 69.9%. The gangue in an itabirite ore consists predominantly of quartz (SiO.sub.2), which is determined as Si by WDXRF and recalculated as SiO.sub.2 in the concentrate. For a calculation of Separation Efficiency, only the iron content of the fraction is used.

[0250] F) Flotation

[0251] F-1: Flotation of an Itabirite Type Iron Ore

[0252] 500 g ground itabirite type iron ore (iron mainly contained as haematite, 43.9 wt. % Fe and 33.9 wt. % SiO.sub.2) and 333 mL distilled water are placed in a 1.5 L flotation cell in a CDC flotation machine and agitated at 1000 rpm. The slurry is conditioned with causticized starch solution St-1 in an amount corresponding to 500 g starch per ton of dried ore (25 g of a causticized starch solution St-1 with 1 wt. % concentration) for 3 min. The pH is kept at 9.8 using 5 wt. % aqueous NaOH solution. Subsequently, approximately 7.5 or 10 g of 1 wt. % collector solution as described in the tables F-1-1 and F-1-2 corresponding to approximately 150 or 200 g collector per ton of dried ore is added to the slurry and conditioned for 1 min.

[0253] After conditioning, further 600 mL distilled water are added and the slurry is aerated at 1 L/min until the completion of the flotation (3 min). The froth fraction is collected and aeration stopped. The water level is maintained during the entire flotation time. The remaining cell fraction (further described as concentrate) and separated froth (further described as tailings) are dried in an oven at 100 C., weighed, homogenized, and their contents of Fe and Si are determined using EDXRF in a lithium borate fused bead matrix. The Si content is recorded as SiO.sub.2. The results are listed in tables F-1-1 and F-1-2.

TABLE-US-00002 TABLE F-1-1 example No. F-1-1-1 .sup.a) F-1-1-2 .sup.b) F-1-1-3 .sup.a) F-1-1-4 .sup.b) F-1-1-5 .sup.b) collector D-1-1 D-1-2 D-1-3 D-1-4 D-1-5 solution collector (101) (101) + (102) (102) + (102) + (201) (201) (202) amount .sup.c) 100 90:10 100 90:10 98:2 dosage [g/t] 200 150 150 150 150 SE .sup.d) 83.9 85.9 81.6 83.8 87.4 Fe grade 66.9 66.5 67.1 66.9 67.0 conc. .sup.e) [wt. %] SiO.sub.2 conc. .sup.f) 1.04 1.93 0.73 0.71 1.31 wt. %] Fe tailings .sup.g) 10.0 6.9 12.5 10.0 6.5 [wt. %] SiO.sub.2 86.4 91.4 82.7 84.5 91.3 tailings .sup.h) [wt. %] Fe recovery 92.4 95.2 90.6 92.0 94.8 in conc. .sup.i) [%] observations j) j) Footnotes: .sup.a) comparative .sup.b) inventive .sup.c) relative weight parts of amidoamine collector and non-ionic collector based on the sum of 100 parts for the amidoamine collector and - if present - the non-ionic collector .sup.d) Separation Efficiency .sup.e) weight percentage of Fe in the cell concentrate .sup.f) weight percentage of SiO.sub.2 in the cell concentrate .sup.g) weight percentage of Fe in the tailings (separated froth) .sup.h) weight percentage of SiO.sub.2 in the tailings (separated froth) .sup.i) recovery of Fe in the cell concentrate based on overall Fe in the ore j) higher but still acceptable SiO.sub.2 content in concentrate offset by lower Fe losses into tailings

TABLE-US-00003 TABLE F-1-2 example No. F-1-2-1 .sup.a) F-1-2-2 .sup.b) F-1-2-3 .sup.b) F-1-2-4 .sup.a) collector D-1-6 D-1-7 D-1-8 D-1-9 solution collector (104) (104) + (104) + (104) + (201) (202) (203) amount .sup.c) 100 90:10 98:2 90:10 dosage [g/t] 200 150 200 200 SE .sup.d) 76.4 83.9 83.2 75.9 Fe grade conc. .sup.e) 67.2 67.4 67.3 67.2 [wt. %] SiO.sub.2 conc. .sup.f) 0.77 0.85 1.03 0.83 [wt. %] Fe tailings .sup.g) 17.0 10.9 11.4 17.4 [wt. %] SiO.sub.2 tailings .sup.h) 76.1 84.2 83.4 74.0 [wt. %] Fe recovery in 83.3 91.2 90.4 84.6 conc. .sup.i) [%] observations j) j) k) Footnotes: .sup.a) comparative .sup.b) inventive .sup.c) relative weight parts of amidoamine collector and non-ionic collector based on the sum of 100 parts for the amidoamine collector and - if present - the non-ionic collector .sup.d) Separation Efficiency .sup.e) weight percentage of Fe in the cell concentrate .sup.f) weight percentage of SiO.sub.2 in the cell concentrate .sup.g) weight percentage of Fe in the tailings (separated froth) .sup.h) weight percentage of SiO.sub.2 in the tailings (separated froth) .sup.i) recovery of Fe in the cell concentrate based on overall Fe in the ore j) higher but still acceptable SiO.sub.2 content in concentrate offset by lower Fe losses into tailings k) not acceptable results due to high Fe loss into tailings and lower SE compared with the amidoamine itself

[0254] The results in tables F-1-1 and F-1-2 show that the use of inventive collector compositions comprising amidoamine collector and non-ionic collector result in an improved separative performance in comparison to a use of the amidoamine collector alone. The comparison of the results of the inventive example F-1-2-2 versus the comparative examples F-1-2-1 and F-1-2-4 show that not each non-ionic collector is suitable for a combination with an amidoamine collector respectively that an average degree of branching above 1 is detrimental for the combination. Concerning a SiO.sub.2 content in the concentrate, it is noted that each mine site establishes its commercially acceptable upper limit, for example <2 wt. % SiO.sub.2 in the concentrate. The Fe grade conc. values are influenced by the wt. % SiO.sub.2 in the concentrate, which means that if the commercially acceptable upper limit of SiO.sub.2 content in the concentrate is reached, the Fe recovery is decisive for a performance of a collector.