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

Abstract

Compounds of the 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 an aliphatic alkylene group containing 2 to 6 carbon atoms; Z is an aliphatic alkylene group containing 2 to 6 carbon atoms; Y.sup. is an anion; and R is an aliphatic iso C.sub.13H.sub.27-group with average branching degree ranging from 1.5 to 3.5. The compounds are particularly suitable as flotation collectors for enriching an iron mineral from a silicate-containing iron ore.

Claims

1. A process for enriching an iron mineral from a silicate-containing iron ore, the process comprising: performing inverse flotation with a collector or collector formulation comprising at least one compound of any of formulae (Ia), (Ib), (IIa) and (IIb), to at least partially separate a silicate-containing mineral from the silicate-containing iron ore and provide an iron-enriched mineral:
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 an aliphatic alkylene group containing 2 to 6 carbon atoms; Z is an aliphatic alkylene group containing 2 to 6 carbon atoms; Y.sup. is an anion; and R is an aliphatic iso C.sub.13H.sub.27-group with an average branching degree ranging from 2.0 to 2.5.

2. The process according to claim 1, wherein at least one of X and Z is a linear or branched alkylene group.

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

4. The process according to claim 1, wherein Y.sup. of the compounds of formulae:
ROXNH.sub.3.sup.+Y.sup.(Ib); and
ROXNHZNH.sub.3.sup.+Y.sup.(IIb), is CH.sub.3CO.sub.2.sup..

5. The process according to claim 1, wherein the collector or collector formulation comprises at least one compound selected from the group consisting of compounds of formulae (Ia) and (Ib) in combination with at least one compound selected from the group consisting of compounds of formulae (IIa) and (IIb).

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

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

8. The process according to claim 7, wherein the additional frother is either a branched aliphatic alcohol with 10 or less carbon atoms; and/or an alkyl ethoxylate.

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 10, wherein the depressant is a starch.

12. The process according to claim 1, wherein R has an average degree of branching from 2.0 to 2.4.

13. The process according to claim 1, wherein the inverse flotation is carried out at a pH of from 9.8 to 10.7.

14. The process according to claim 1, wherein the collector or collector formulation further comprises 20-50% by weight of acetic acid.

15. The process according to claim 1, wherein the inverse flotation comprises five froth steps.

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 nC.sub.13H.sub.27OH linear alcohol purchased by Aldrich (branching degree 0), not scope of the invention TDN Tridecanol N from BASF (iC.sub.13H.sub.27OH), produced by trimerization of butene followed by hydroformylation, primary alcohol with average branching degree ranging from 2.0 to 2.4 TMN 3,6,8,8-Tetramethylnonan-1-ol (branching degree 4), not scope of the invention

Synthesis of TDN Ether Amine

a) Addition

(3) ##STR00001##

(4) In a 1 l round bottom flask Tridekanol N (300 g, 1.5 mol) was stirred with NaOMe (30% solution in MeOH, 2.25 g, 0.013 mol at 21 C. acrylonitrile (159 g, 3.0 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).

(5) According to gas chromatogram (GC) mixture contains 3.5% Tridekanol N and 96.4% addition product. Proton NMR confirmed the structure (proton nmr in CDCl.sub.3: =0.65-1.80, m, 25H (CH, CH2, CH3), =2.6, t, 2H (CH2CN), =3.5, t, 2H (CH2O), =3.6, t, 2H (CH2O)).

b) Reduction

(6) ##STR00002##

(7) In a 300 ml autoclave tetrahydrofuran (25 g) was stirred with Raney-Cobalt (2.5 g) was flushed 3 times with nitrogen and stirred (500 rpm). Hydrogen (16.2 l) was added until pressure reached 50 bar and reactor was heated to 120 C. During 80 min reaction product from addition step of Tridekanol N and acrylic nitrile (80 g, 0.316 mol) was added continuously (flow rate 1 ml/min). Pressure was increased to 62 bar. Additional hydrogen was added (39.9 l) until pressure of 280 bar was reached. Mixture was stirred for 6 h under these conditions. Pressure was kept at 280 bar (14.86 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: =0.65-1.65, m, 25H (CH, CH2, CH3), =1.72, t, 2H (CH2), =2.8, t, 2H (CH2), =3.4, t, 2H (CH2O), =3.5, t, 2H (CH2O)) following values were achieved: 2.6% un-reacted nitrile 4.2% alcohol Tridekanol N 90% alkyl ether amine 2% side-product (dimer).

c) Partial Protonation

(8) ##STR00003##

(9) TDN-oxypropylamine (150 g, 0.583 mol) was stirred in a flask at room temperature. Acetic acid (7 g, 0.117 mol) was added drop-wise and stirred for 10 min. A homogeneous solution was observed, which stayed clear and liquid during storage for >6 months.

Synthesis of TDN Ether Diamine

a) Addition

(10) ##STR00004##

(11) Tridecyloxypropylamine based on TDN (74 g, 0.28 mol) was stirred in a round bottom flask at 21 C. Acrylonitrile (16 g, 0.30 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: =0.65-1.65, m, 25H (CH, CH2, CH3), =1.75, t, (CH2), =2.5, t, (CH2CN), =2.75, t, (CH2), S=2.95, t, (CH2), =3.4, t, (CH2O), =3.5, t, (CH2O)) following values were achieved: 4.8% Tridekanol N 24.8% unreacted alkyl ether amine 2% alkyl ether nitrile 64.4% desired adduct.

b) Reduction

(12) ##STR00005##

(13) In a 300 ml autoclave tetrahydrofuran (25 g) was stirred with Raney-Cobalt (2.5 g) was flushed 3 times with nitrogen and stirred (500 rpm). Hydrogen (15.9 l) was added until pressure reached 50 bar and reactor was heated to 120 C. During 85 min reaction product from step before (80 g, 0.316 mol) was added continuous (flow rate 1 ml/min). Additional hydrogen was added (41.3 l) until pressure of 280 bar was reached. Mixture was stirred for 6 h under these conditions. Pressure was kept at 280 bar (5.99 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: =0.65-1.65, m, 25H (CH, CH2, CH3), =1.65, q, (CH2), =1.75, t, (CH2), =2.65, m, (CH2), 5=2.75, t, (CH2), =3.4, t, (CH2O), =3.5, t, (CH2O)) following values were achieved: 4.5% alcohol Tridekanol N 10% unreacted nitrile 21.6% alkyl ether amine 62.8% alkyl ether diamine no side-product observed.

c) Partial Protonation

(14) TDN-oxypropyl-1,3-propandiamine (314 g, 1.0 mol) was stirred in a flask at room temperature. Acetic acid (3 g, 0.05 mol) was added drop-wise and stirred for 10 min. A homogeneous solution was observed, which stayed clear and liquid during storage for >6 months.

(15) The other samples were produced in similar way like TDN-oxypropylamine or TDN-oxypropyl-1,3-propandiamine.

Flotation Test

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

(17) 500 g of dried iron ore (hematite) were poured in a 11 flotation vessel of a lab flotation cell (MN 935/5, HUMBOLDT WEDAG). 11 tab 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). The results are shown in table 2.

(18) 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.

(19) TABLE-US-00002 TABLE 2 weight weight Fe.sub.rec SiO.sub.2 pH g % Fe Fe.sub.rec. (Residue) Si SiO.sub.2 (Residue) SiO.sub.2 rec. Flotigam EDA Froth 1 10.5 8 1.6% 25.3% 1.1% 98.9% 24.8% 53.1% 43.7% 1.9% iC12oxypropylamine + Froth 2 10.4 51 10.1% 15.8% 4.3% 94.7% 34.4% 73.6% 40.3% 17.0% 50% acetic acid Froth 3 10.3 57 11.3% 10.2% 3.1% 91.6% 38.7% 82.8% 34.0% 21.3% (Comparative) Froth 4 10.0 28 5.5% 7.6% 1.1% 90.5% 40.1% 85.8% 30.0% 10.9% Froth 5 9.9 42 8.3% 9.3% 2.1% 88.4% 39.3% 84.1% 22.9% 16.0% Residue 319 63.2% 52.3% 88.4% 10.7% 22.9% 33.0% Total 505 100.0% 37.4% 100.0% 20.5% 43.8% 100.0% Aerosurf MG-83 Froth 1 10.3 63 12.5% 9.9% 3.2% 96.8% 38.8% 83.0% 38.4% 23.5% iC13oxypropyl-1,3- Froth 2 10.2 151 29.9% 11.4% 8.9% 87.8% 38.1% 81.5% 16.1% 55.4% propan diamine + Froth 3 9.5 31 6.1% 18.7% 3.0% 84.8% 32.6% 69.7% 9.7% 9.7% 5% acetic acid Froth 4 9.4 51 10.1% 51.3% 13.6% 71.3% 11.7% 25.0% 5.9% 5.7% (Comparative) Froth 5 9.0 9 1.8% 59.2% 2.8% 68.5% 6.8% 14.5% 5.6% 0.6% Residue 200 39.6% 66.1% 68.5% 2.6% 5.6% 5.0% Total 505 100.0% 38.2% 100.0% 20.6% 44.0% 100.0% Lilaflot D 817M Froth 1 10.2 47 9.3% 9.7% 2.4% 97.6% 38.8% 83.0% 39.3% 17.9% iC12oxypropyl-1,3- Froth 2 10.0 43 8.5% 11.9% 2.7% 95.0% 37.5% 80.2% 35.0% 15.8% propan diamine + Froth 3 9.6 11 2.2% 7.5% 0.4% 94.5% 40.9% 87.5% 33.6% 4.4% 20-40% acetic Froth 4 9.6 16 3.2% 10.5% 0.9% 93.6% 38.7% 82.8% 31.6% 6.1% acid Froth 5 9.5 16 3.2% 16.5% 1.4% 92.3% 34.6% 74.0% 29.7% 5.4% (Comparative) Residue 371 73.6% 47.7% 92.3% 13.9% 29.7% 50.5% Total 504 100.0% 38.1% 100.0% 20.3% 43.4% 100.0% Tridecyl- Froth 1 10.7 0 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 43.5% 0.0% oxypropylamine # + Froth 2 10.7 19 3.8% 14.4% 1.4% 98.6% 35.3% 75.5% 42.2% 6.5% 50% acetic acid Froth 3 10.6 77 15.2% 5.5% 2.2% 96.4% 42.2% 90.3% 33.2% 31.7% Froth 4 10.1 113 22.4% 5.0% 2.9% 93.5% 42.7% 91.3% 10.9% 47.0% Froth 5 10.1 28 5.5% 16.1% 2.3% 91.2% 34.9% 74.7% 4.3% 9.5% Residue 268 53.1% 66.5% 91.2% 2.0% 4.3% 5.2% Total 505 100.0% 38.7% 100.0% 20.3% 43.5% 100.0% Tridecyloxypropyl- Froth 1 10.2 23 4.6% 2.9% 0.3% 99.7% 40.6% 86.9% 39.9% 9.4% 1,3-propan- Froth 2 10.2 141 27.9% 4.9% 3.6% 96.1% 40.0% 85.6% 21.0% 56.8% diamine # + Froth 3 9.9 61 12.1% 4.6% 1.5% 94.6% 42.3% 90.5% 5.9% 26.0% 20% acetic acid Froth 4 9.8 15 3.0% 15.0% 1.2% 93.4% 34.7% 74.2% 2.0% 5.2% Froth 5 9.8 17 3.4% 59.0% 5.2% 88.2% 6.0% 12.8% 1.3% 1.0% Residue 248 49.1% 68.3% 88.2% 0.6% 1.3% 1.5% Total 505 100.0% 38.0% 100.0% 19.7% 42.0% 100.0% 3,6,8,8-tetra- Froth 1 10.4 0 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 42.4% 0.0% methylnonan-1- Froth 2 10.3 0 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 42.4% 0.0% amine + Froth 3 10.3 109 21.7% 5.4% 3.0% 97.0% 42.1% 90.1% 29.2% 46.1% 50% acetic acid Froth 4 10.0 67 13.3% 4.8% 1.6% 95.4% 42.6% 91.1% 16.4% 28.7% (based on TMN) Froth 5 9.9 34 6.8% 7.1% 1.2% 94.2% 41.0% 87.7% 8.1% 14.0% (Comparative) Residue 292 58.2% 63.5% 94.2% 3.8% 8.1% 11.2% Total 502 100.0% 39.2% 100.0% 19.8% 42.4% 100.0% 50% (Tridecyl- Froth 1 10.5 39 7.7% 3.0% 0.5% 99.5% 44.3% 94.8% 22.3% oxypropylamine # + Froth 2 10.3 110 21.7% 5.2% 2.4% 97.1% 42.7% 91.3% 8.0% 60.6% 50% acetic acid) + Froth 3 9.9 14 2.8% 7.9% 0.5% 96.6% 40.8% 87.3% 4.7% 7.4% 50% (Tridecyloxy- Froth 4 9.9 10 2.0% 34.0% 1.4% 95.2% 22.8% 48.8% 3.4% 2.9% propyl- Froth 5 9.8 6 1.2% 34.0% 0.9% 94.3% 22.8% 48.8% 2.6% 1.8% 1,3-propandiamine # + Residue 327 64.6% 67.9% 94.3% 1.2% 2.6% 5.1% 5% acetic acid) Total 506 100.0% 46.5% 100.0% 15.3% 32.8% 100.0% # average branching degree ranging from 2.0 to 2.4.