Amine and diamine compounds and their use for inverse froth flotation of silicate from iron ore

Abstract

The invention relates to a process for enriching an iron mineral from a silicate containing iron ore by inverse flotation comprising the addition of a collector or collector composition comprising at least one of the compounds of formulae ROXNH.sub.2 (Ia); ROXNH.sub.3.sup.+Y.sup. (Ib); ROXNHZNH.sub.2 (IIa); and ROXNHZNH.sub.3.sup.+Y.sup. (IIb), in which X is a linear or branched aliphatic alkylene group containing 2 to 6 carbon atoms; Z is a linear or branched aliphatic alkylene group containing 2 to 6 carbon atoms; Y is an anion; and R is an aliphatic group of the formula (I) C.sub.5H.sub.11CH(C.sub.3H.sub.7)CH.sub.2 (I) wherein the C.sub.5H.sub.11 moeity of the aliphatic group of the formula (I) comprises 70 to 99% by weight n-C.sub.5H.sub.11, and 1 to 30% by weight C.sub.2H.sub.5CH(CH.sub.3)CH.sub.2 and/or CH.sub.3CH(CH.sub.3)CH.sub.2CH.sub.2.
ROXNH.sub.2(Ia)
ROXNH.sub.3.sup.+Y.sup.(Ib)
ROXNHZNH.sub.2(IIa)
ROXNHZNH.sub.3.sup.+Y.sup.(IIb)
C.sub.5H.sub.11CH(C.sub.3H.sub.7)CH.sub.2(I)

Claims

1. A process for enriching an iron mineral from a silicate-containing iron ore, the process comprising: performing inverse flotation by adding, to the silicate-containing iron ore, a collector or collector composition comprising at least one selected from the group consisting of compounds of formulae:
ROXNH.sub.2(Ia);
ROXNH.sub.3.sup.+Y.sup.(Ib);
ROXNHZNH.sub.2(IIa); and
ROXNHZNH.sub.3.sup.+Y.sup.(IIb), wherein X is a linear or branched aliphatic alkylene group containing 2 to 6 carbon atoms; Z is a linear or branched aliphatic alkylene group containing 2 to 6 carbon atoms; Y.sup. is an anion; and R is an aliphatic group of formula (I):
C.sub.5H.sub.11CH(C.sub.3H.sub.7)CH.sub.2(I) wherein the C.sub.5H.sub.11 moiety of the aliphatic group of the formula (I) comprises: from 70 to 99% by weight of n-O.sub.5H.sub.11, and from 1 to 30% by weight of C.sub.2H.sub.5CH(CH.sub.3)CH.sub.2 and/or CH.sub.3CH(CH.sub.3)CH.sub.2CH.sub.2.

2. The process according to claim 1, wherein a C.sub.3H.sub.7 moiety of formula (I) is n-C.sub.3H.sub.7.

3. The process according to claim 1, wherein the collector or collector composition further comprises at least one selected from the group consisting of compounds of formulae:
ROXNH.sub.2(Ic);
ROXNH.sub.3.sup.+Y.sup.(Id);
ROXNHZNH.sub.2(IIc); and
ROXNHZNH.sub.3.sup.+Y.sup.(IId), wherein X is a linear or branched aliphatic alkylene group containing 2 to 6 carbon atoms; Z is a linear or branched aliphatic alkylene group containing 2 to 6 carbon atoms; Y.sup. is an anion; and R is an aliphatic C.sub.13H.sub.27 group and/or an aliphatic C.sub.15H.sub.31 group each with an average branching degree ranging from 0.1 to 0.9.

4. The process according to claim 1, wherein the collector or collector composition further comprises: at least one selected from the group consisting of compounds of formulae:
ROXNH.sub.2(Ie);
ROXNH.sub.3.sup.+Y.sup.(If);
ROXNHZNH.sub.2(IIe); and
ROXNHZNH.sub.3.sup.+Y.sup.(IIf), wherein X is a linear or branched aliphatic alkylene group containing 2 to 6 carbon atoms; Z is a linear or branched aliphatic alkylene group containing 2 to 6 carbon atoms; Y.sup. is an anion; and R is a linear aliphatic C.sub.12H.sub.25 group and/or a linear aliphatic C.sub.14H.sub.29 group.

5. The process according to claim 1, wherein at least one of X and Z is an CH.sub.2CH.sub.2CH.sub.2 moiety.

6. The process according to claim 1, wherein Y.sup. is CH.sub.3CO.sub.2.sup..

7. The process according to claim 1, further comprising performing froth flotation.

8. The process according to claim 1, further comprising employing an additional frother.

9. The process according to claim 1, wherein the iron ore is haematite.

10. The process according to claim 1, further comprising adding a depressant.

11. The process according to claim 1, wherein the collector or the collector composition comprises at least one selected from the group consisting of compounds of formulae:
ROXNH.sub.2(Ia)
ROXNH.sub.3.sup.+Y.sup.(Ib).

12. The process according to claim 1, wherein R is an aliphatic Guerbet C.sub.10H.sub.21 group with an average degree of branching of between 1.01 and 1.60.

Description

EXAMPLES

Synthesis

(1) Following alcohols have been transformed into corresponding alkyl ether amines by conversion with acrylonitrile and reduction of nitrile group to amino group. Compounds were optionally treated with acetic acid afterwards. Alkyl ether diamines have been produced from corresponding alkyl ether amines by conversion with acrylonitrile and reduction of nitrile group to amino group. Compounds were optionally treated with acetic acid afterwards.

(2) TABLE-US-00001 TABLE 1 Alcohol Description nC10 n-C10H21OH, linear alcohol purchased by Aldrich (branching degree 0), not scope of the invention C10-Guerbet C.sub.5H.sub.11CH(C.sub.3H.sub.7)CH.sub.2OH with the restriction that for 70-99 weight % of compound C.sub.5H.sub.11 means n-C.sub.5H.sub.11 and for 1-30 weight % C.sub.5H.sub.11 means C.sub.2H.sub.5CH(CH.sub.3)CH.sub.2 and/or CH.sub.3CH(CH.sub.3)CH.sub.2CH.sub.2. Produced by BASF via dimerization of slightly branched C5-aldehyde via aldol reaction followed by hydrogenation. C13C15 C13C15 oxo-alcohol from BASF, produced by hydro- formylation of C12C14-alpha-olefin, primary alcohol with average branching degree ranging from 0.3 to 0.7 C12C14 linear fatty alcohol with 12 and 14 carbon atoms THV Tetrahydrolavandulol, 2-Isopropyl-5-methylhexan-1-ol (Guerbet-alcohol with branching degree 3)

(3) To illustrate synthesis route the examples employ conversion of alcohol mixture ROH 50 weight % C10-Guerbet/50 weight % C13C15.

Synthesis of C10-Guerbet/C13C15 ether amine

(4) a) Addition

(5) ##STR00001##

(6) In a 11 round bottom flask C10-Guerbet alcohol (159 g, 1.0 mol) and C13C15 alcohol (159 g, 0.75 mol) were stirred with NaOMe (30% solution in MeOH, 2.62 g, 0.015 mol at 21 C. Acrylonitrile (186 g, 3.5 mol) was added during 45 min in such a way that temperature was kept below 50 C. Reaction was stirred overnight. Excess of acrylonitrile was removed under vacuum (20 mbar) at 50 C. (and later at 75 C.) within 30 min. Ambosol (3 weight %) was added and mixture was filtrated (900 k Seitz filter).

(7) According to gas chromatogram (GC) mixture contains 1% alcohol and 99% addition product. Proton NMR (proton nmr in CDCl.sub.3: =0.85-1.70, m, 22.4; H (CH, CH2, CH3), =2.6, t, 2H (CH2CN), =3.2-3.5, m, 2H (CH2O), =3.6, m, 2H (CH2O)) confirmed the structure.

(8) b) Reduction

(9) ##STR00002##

(10) In a 300 ml autoclave tetrahydrofuran (35 g) was stirred with Raney-Cobalt (3.6 g) was flushed 3 times with nitrogen and stirred (500 rpm). Hydrogen (16.4 l) was added until pressure reached 50 bar and reactor was heated to 120 C. Product from addition step of C10-Guerbet/C13C15 and acrylonitrile (120 g, 0.51 mol) was added continuously (flow rate 1 ml/min). Pressure was increased to 60 bar. Additional hydrogen was added (17.7 l) until pressure of 280 bar was reached. Mixture was stirred for 6 h under these conditions. Pressure was kept at 280 bar (19.72 l were added). Reactor was cooled to room temperature and pressure gently released. Autoclave was flushed with nitrogen (10 bar). Catalyst was removed by filtration (Seitz K 900). According to amine titer, GC and proton NMR (proton nmr in CDCl.sub.3: =0.8-1.7, m, 22.4; H (CH, CH2, CH3), =1.72, t, 2H (CH2), =2.8, t, 2H (CH2), =3.15-3.4, m, 2H (CH2O), =3.5, m, 2H (CH2O)) following values were achieved: 1.5% un-reacted nitrile 2.5% alcohol 94% alkyl ether amine 1.5% side-product (dimer).
c) Partial Protonation

(11) ##STR00003##

(12) C10-Guerbet/C13C15-oxypropylamine (12 g, 0.050 mol) was stirred in a flask at room temperature. Acetic acid (0.6 g, 0.010 mol) was added drop-wise and stirred for 10 min. A homogeneous solution was observed, which stayed clear and liquid during storage for >3 months.

Synthesis of C10-Guerbet/C13C15 ether diamine

(13) a) Addition

(14) ##STR00004##

(15) C10-Guerbet/C13C15-oxypropylamine (270 g, 1.08 mol) was stirred in a round bottom flask at 21 C. Acrylonitrile (63 g, 1.19 mol) was added during 15 min in such a way that temperature was kept below 50 C. Reaction was stirred for 3 h. Excess of acrylonitrile was removed under vacuum (20 mbar) at 50 C. (and later at 75 C.) within 30 min. According to amine titer, GC and proton NMR (proton nmr in CDCl.sub.3: =0.8-1.70, m, 22.4H (CH, CH2, CH3), =1.75, t, (CH2), =2.5, t, (CH2CN), =2.75, t, (CH2), =2.95, t, (CH2), =3.15-3.4, m, (CH2O), =3.5, m, (CH2O)) following values were achieved: 2.7% alcohol 2.7% unreacted alkyl ether amin 7.6% side product 87% desired adduct.
b) Reduction

(16) ##STR00005##

(17) In an autoclave tetrahydrofuran (110 g) was stirred with Raney-Cobalt (13 g) was flushed 3 times with nitrogen and stirred (500 rpm). Hydrogen (123.7 l) was added until pressure reached 50 bar and reactor was heated to 120 C. Addition product of acrylonitrile and C10-Guerbet/C13C15-oxypropylamine (323 g, 1.109 mol) was added continuously (flow rate 6 ml/min). Pressure increased to 68 bar. Additional hydrogen was added until pressure of 280 bar was reached. Mixture was stirred for 6 h under these conditions. Pressure was kept at 280 bar (2.47 l were added). Reactor was cooled to room temperature and pressure gently released. Autoclave was flushed with nitrogen (10 bar). Catalyst was removed by filtration (Seitz K 900). According to amine titer, GC and proton NMR (proton nmr in CDCl.sub.3: =0.85-1.60, m, 22.4H (CH, CH2, CH3), =1.65, q, (CH2), =1.75, t, (CH2), =2.70, m, (CH2), =2.75, t, (CH2), =3.15-3.4, m, (CH2O), =3.45, t, (CH2O)) following values were achieved: 4% alcohol 5.5% alkyl ether amine 84.5% alkyl ether diamine 6% side-product.
c) Partial Protonation

(18) C10-Guerbet/C13C15-oxypropyl-1,3-propandiamine (80 g, 0.27 mol) was stirred in a flask at room temperature. Acetic acid (0.8 g, 0.0135 mol) was added drop-wise and stirred for 10 min. A homogeneous solution was observed, which stayed clear and liquid during storage for >3 months.

(19) The other samples were produced in similar way like C10-Guerbet/C13C15-oxypropylamine or C10-Guerbet/C13C15-oxypropyl-1,3-propandiamine.

(20) Flotation Test

(21) Following flotation protocol was applied for the different collectors.

(22) 500 g of dried iron ore (hematite) were poured in a 1 l flotation vessel of a lab flotation cell (MN 935/5, HUMBOLDT WEDAG). 1 l tap water was added and the resulting slurry was homogenized by stirring for two minutes (3000 rpm). 25 mL of a 1 weight % freshly prepared corn starch solution (=500 g/t ore) were mixed in. Subsequently, 25 L of the liquid collector were injected (=50 g/t ore), pH was adjusted to 10 (with 50 weight-% NaOH solution) and the slurry was conditioned for 5 minutes. The air flow was started (80 L/h) and the froth was collected until no stable froth was formed. The air flow was stopped and another 25 L of collector were added and conditioned for 5 minutes, before the air flow was restarted. This procedure was repeated until five addition steps were carried out. The flotation froth of each step was dried, weighted and the obtained minerals characterized by elementary analysis via X-ray fluorescence (XRF).

(23) It can be seen from the test work that the collectors according to the invention provide a better all-round combination of increased removal of silicate and increased retention of the iron mineral.

(24) TABLE-US-00002 TABLE 2 Fe.sub.rec SiO.sub.2 pH weight g weight % Fe Fe.sub.rec. (Residue) Si SiO.sub.2 (Residue) SiO.sub.2 rec. Flotigam EDA Froth 1 10.6 2 0.4% 7.2% 0.1% 99.9% 40.9% 87.5% 33.4% 1.0% iC12oxypropylamine + Froth 2 10.4 3 0.6% 7.2% 0.1% 99.8% 40.9% 87.5% 33.1% 1.5% 50% acetic acid Froth 3 10.3 10 2.0% 7.2% 0.3% 99.5% 40.9% 87.5% 32.0% 5.2% (Comparative Froth 4 10.3 21 4.2% 4.2% 0.4% 99.1% 43.4% 92.8% 29.2% 11.5% monoamine) Froth 5 10.2 22 4.4% 3.9% 0.4% 98.8% 43.4% 92.8% 26.1% 12.0% Residue 447 88.5% 50.4% 98.8% 12.2% 26.1% 68.7% Total 505 100.0% 45.2% 100.0% 15.7% 33.6% 100.0% Aerosurf MG-83 Froth 1 10.6 8 1.6% 12.4% 0.4% 99.6% 36.9% 78.9% 34.3% 3.6% iC13oxypropyl-1,3- Froth 2 10.4 6 1.2% 17.0% 0.5% 99.1% 33.5% 71.7% 33.8% 2.4% propan diamine + Froth 3 10.3 14 2.8% 16.4% 1.0% 98.1% 34.3% 73.4% 32.6% 5.8% 5% acetic acid Froth 4 9.8 55 10.9% 4.7% 1.1% 96.9% 42.9% 91.8% 24.9% 28.6% (Comparative Froth 5 9.8 103 20.4% 9.1% 4.2% 92.8% 39.7% 84.9% 5.6% 49.5% diamine) Residue 319 63.2% 65.4% 92.8% 2.6% 5.6% 10.0% Total 505 100.0% 44.5% 100.0% 16.3% 35.0% 100.0% Product 1 Froth 1 10.2 9 1.8% 6.5% 0.2% 99.8% 40.9% 87.5% 31.7% 4.8% 1:1 (C10-Guerbetoxypropylamine + Froth 2 10.2 41 8.1% 6.5% 1.1% 98.6% 41.5% 88.8% 26.6% 22.0% C 12/14- Froth 3 9.9 50 9.9% 3.6% 0.8% 97.9% 43.7% 93.5% 18.3% 28.3% oxypropylamine) + Froth 4 9.8 35 6.9% 4.5% 0.7% 97.2% 43.0% 92.0% 11.3% 19.5% 20% acetic acid Froth 5 9.8 23 4.6% 6.6% 0.6% 96.6% 41.6% 89.0% 6.2% 12.4% Residue 347 68.7% 66.5% 96.6% 2.9% 6.2% 13.0% Total 505 100.0% 47.3% 100.0% 15.3% 32.7% 100.0% Product 2 Froth 1 10.4 0 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 33.7% 0.0% 1:1 (C10-Guerbetoxypropylamine + Froth 2 10.4 25 5.0% 4.5% 0.5% 99.5% 43.0% 92.0% 30.7% 13.6% C 13/15- Froth 3 10.4 64 12.8% 4.3% 1.2% 98.3% 43.3% 92.6% 21.0% 35.1% oxypropylamine) + Froth 4 9.9 50 10.0% 3.7% 0.8% 97.5% 43.8% 93.7% 11.0% 27.7% 5% acetic acid Froth 5 9.9 22 4.4% 7.4% 0.7% 96.8% 41.3% 88.3% 6.0% 11.5% Residue 340 67.9% 65.3% 96.8% 2.8% 6.0% 12.1% Total 501 100.0% 45.8% 100.0% 15.8% 33.7% 100.0%

(25) As one can see in table 2 commercial available Flotigam EDA used in example lead after 5 times flotation of iron ore to a residue still containing a relative high content of SiO2 (26.1%). In order to receive lower values of SiO2 in a residue after 5 times flotation one would need the more selective but also much more expensive and more complex alkyl ether diamines Aerosurf MG 83.

(26) Surprisingly it was found that a combination of claimed compounds similar level of SiO.sub.2 to the Aerosurf MG 83 can be reached. In case of product 2 a SiO.sub.2 residual content of 6.0% was reached. The residual silica content is similar to that of Aerosurf MG 83 (5.6% SiO2), but the recovery rate of precious Fe was much higher for the inventive product (residue: 96.8% Fe compared to residue 92.8% Fe, for the Aerosurf MG 83). The advantage of the claimed combinations of alkyl ether amines is that one has a liquid sample, which is capable to reach similar low level of SiO2 level in treated ore, while loss of Fe is much lower compared to much more expensive and more complex to produce alkyl ether diamines.

(27) TABLE-US-00003 TABLE 3 SiO2 SiO2 pH weight g weight % Fe Ferec. Frec (Residue) Si SiO2 (Residue) rec. nC10oxypropylamine + Froth 1 10.6 0 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 33.2% 0.0% 50 mol % acetic acid Froth 2 10.6 21 4.2% 5.7% 0.5% 99.5% 41.9% 89.6% 30.8% 11.3% Froth 3 10.5 23 4.6% 4.0% 0.4% 99.1% 43.2% 92.4% 27.7% 12.7% Froth 4 10.5 26 5.2% 4.5% 0.5% 98.6% 43.2% 92.4% 23.8% 14.4% Froth 5 10.3 25 5.0% 5.6% 0.6% 98.0% 42.2% 90.3% 19.7% 13.5% Residue 407 81.1% 55.2% 98.0% 9.2% 19.7% 48.0% Total 502 100.0% 45.7% 100.0% 15.5% 33.2% 100.0% C10- Froth 1 10.2 0 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 33.4% 0.0% Guerbetoxypropylamine + Froth 2 10.1 0 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 33.4% 0.0% 50 mol % acetic acid Froth 3 10.1 0 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 33.4% 0.0% Froth 4 10.1 33 6.6% 2.2% 0.3% 99.7% 44.7% 95.6% 29.0% 18.9% Froth 5 10.1 21 4.2% 2.1% 0.2% 99.5% 44.8% 95.8% 25.9% 12.1% Residue 445 89.2% 50.4% 99.5% 12.1% 25.9% 69.0% Total 499 100.0% 45.2% 100.0% 15.6% 33.4% 100.0% THVoxypropylamine + Froth 1 10.4 0 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 30.0% 0.0% 50 mol % acetic acid Froth 2 10.4 0 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 30.0% 0.0% Froth 3 10.3 0 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 30.0% 0.0% Froth 4 10.3 13 2.6% 2.5% 0.1% 99.9% 44.7% 95.6% 28.3% 8.2% Froth 5 10.2 8 1.6% 2.6% 0.1% 99.8% 44.8% 95.8% 27.2% 5.1% Residue 481 95.8% 49.3% 99.8% 12.7% 27.2% 86.7% Total 502 100.0% 47.3% 100.0% 14.0% 30.0% 100.0%

(28) As one can see in table 3 C10-based alkyl ether amines can be used in general to remove larger parts of SiO2 within a precleaning step. In this step removal of significant loss of SiO2 is the goal at almost no loss of precious Fe. Collector based on linear C10-alcohol has two disadvantages. First of all it is solid. One needs a separate heating unit to keep it liquid for easy dosage. Second disadvantage can be seen in FE3-AH 182. While final SiO2 level in precleaning step is much lower compared to the other examples in table 3, loss of Fe is highest (2%). In case of the claimed compounds the loss of Fe is much lower (0.5% Fe max).