METHOD FOR FLOTATION OF A SILICATE-CONTAINING IRON ORE WITH A CATIONIC COLLECTOR

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 reverse flotation, which method comprises the step of (c) adding a compound of formula I wherein R.sup.1 is C.sub.9-C.sub.22 alkyl or alkenyl, which is linear or branched, R.sup.2 is H, C.sub.1-C.sub.4 alkyl, which is linear or branched, R.sup.3 is —X—NH.sub.2, H or C.sub.1-C.sub.4 alkyl, which is linear or branched, and X is C.sub.2-C.sub.4 alkylene, which is linear or branched, or a salt of a protonated compound of formula I and an anion, to a prepared aqueous pulp of the ore and optionally one or more flotation auxiliaries to obtain an aqueous mixture. Furthermore, a method for manufacturing a specific group of compounds of formula I, i.e. compounds of formula 1-X wherein R.sup.1 is C.sub.9-C.sub.15 alkyl, which is linear or branched, R.sup.2 is H, R.sup.3 is —X—NH.sub.2 and X is C.sub.2-C.sub.4 alkylene, which is linear or branched, is disclosed.

##STR00001##

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, method comprising: adding a compound of formula I ##STR00021## wherein R.sup.1 is C.sub.9-C.sub.22 alkyl or alkenyl, which is linear or branched, R.sup.2 is H, C.sub.1-C.sub.4 alkyl, which is linear or branched, R.sup.3 is —X—NH.sub.2, H or C.sub.1-C.sub.4 alkyl, which is linear or branched, and X is C.sub.2-C.sub.4 alkylene, which is linear or branched, or a salt of a protonated compound of formula I and an anion, to a prepared aqueous pulp of the ore and optionally one or more flotation auxiliaries to obtain an aqueous mixture.

2. The method according to claim 1, comprising: providing the ore, which contains the iron mineral and silicate, preparing from the provided ore by addition of water, and optionally one or more flotation auxiliaries, an aqueous pulp, adding the compound of formula I to the prepared aqueous pulp of the ore, and optionally one or more flotation auxiliaries, to obtain an aqueous mixture, 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, and obtaining from the flotation cell the concentrate enriched in iron mineral content.

3. The method according to claim 1, wherein R.sup.1 is C.sub.9-C.sub.15 alkyl, which is linear or branched, R.sup.2 is H, R.sup.3 is —X—NH.sub.2 and X is C.sub.2-C.sub.4 alkylene, which is linear or branched.

4. The method according to claim 1, wherein X is —CH.sub.2—CH.sub.2— or —CH.sub.2—CH.sub.2—CH.sub.2—.

5. The method according to claim 1, wherein R.sup.1 is C.sub.10-C.sub.14 alkyl, which is linear or branched.

6. The method according to claim 1, wherein the compound of formula I is compound (101) or compound (102) ##STR00022##

7. 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.

8. The method according to claim 1, wherein the compound of formula I is added in an amount between 10 g to 300 g per ton of the ore.

9. The method according to claim 1, wherein the adding is at a pH value between 8 and 12.

10. The method according to claim 2, wherein the one or more flotation auxiliaries comprises a depressing agent, a froth regulator, a co-collector or an extender oil.

11. The method according to claim 10, wherein the depressing agent comprises a starch.

12. A method of using the compound of formula I as defined in claim 1 or a salt of a protonated compound of formula I and an anion as defined in claim 1 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.

13. The method according to claim 12, wherein R.sup.1 is C.sub.9-C.sub.15 alkyl, which is linear or branched, R.sup.2 is H, R.sup.3 is —X—NH.sub.2 and X is C.sub.2-C.sub.4 alkylene, which is linear or branched.

14. A compound of formula I ##STR00023## wherein R.sup.1 is C.sub.9-C.sub.15 alkyl, which is linear or branched, R.sup.2 is H, R.sup.3 is —X—NH.sub.2 and X is C.sub.2-C.sub.4 alkylene, which is linear or branched, or a salt of a protonated compound of formula I and an anion.

15. A method for manufacturing a compound of formula I ##STR00024## wherein R.sup.1 is C.sub.9-C.sub.15 alkyl, which is linear or branched, R.sup.2 is H, R.sup.3 is —X—NH.sub.2 and X is C.sub.2-C.sub.4 alkylene, which is linear or branched, the method comprising: reacting a compound of formula INT-I-1 ##STR00025## and a base, or a compound of formula INT-I-2 ##STR00026## with a compound of the formula INT-II ##STR00027## to obtain the compound of formula I.

Description

[0094] FIGS. 1 to 8 are attached and described below.

[0095] FIG. 1 shows a .sup.1H-NMR spectrum in CDCl.sub.3 of the material obtained at A-2.

[0096] FIG. 2 shows a .sup.1H-NMR spectrum between around 0.5 ppm and around 4.0 ppm of the material obtained at A-2 in CDCl.sub.3. FIG. 2 is an enlarged extract from FIG. 1.

[0097] FIG. 3 shows a .sup.13C-NMR spectrum in CDCl.sub.3 of the material obtained at A-2.

[0098] FIG. 4 shows a .sup.1H-NMR spectrum in CDCl.sub.3 of the material obtained at A-3.

[0099] FIG. 5 shows a .sup.13C-NMR spectrum in CDCl.sub.3 of the material obtained at A-3.

[0100] FIG. 6 shows a .sup.1H-NMR spectrum in CDCl.sub.3 of the material obtained at A-4.

[0101] FIG. 7 shows a .sup.1H-NMR spectrum between around 2.30 ppm and around 2.95 ppm of the material obtained at A-4 in CDCl.sub.3. FIG. 7 is an enlarged extract from FIG. 6.

[0102] FIG. 8 shows a .sup.13C-NMR spectrum in CDCl.sub.3 of the material obtained at A-4.

[0103] The following examples illustrate further the invention without limiting it. Percentage values are percentage by weight if not stated differently.

[0104] A) Employed Collectors and Precursor

A-1: N′-(isotridecoxypropyl)propane-1,3-diamine

[0105] ##STR00017##

[0106] Isotridecanol N (degree of branching ˜2.2) is reacted in a Michael addition with acrylonitrile in a molar ratio of 1:1. This is followed by hydrogenating the intermediate over Raney cobalt to generate 3-isotridecoxypropan-1-amine. In a following stage, additional acrylonitrile is added in a molar ratio of 1:1 and reacted in a Michael addition. Afterwards, a hydrogenation over Raney cobalt is conducted. The obtained material contains as measured by gas chromatography 2.9% isotridecanol N, 11.7% isotridecoxypropane-1-amine, 78.1% N′-(isotridecoxypropyl)propane-1,3-diamine (as depicted as compound (301)) and 4.0% N′-[3-(3-tridecoxypropylamino)propyl]propane-1,3-diamine. The obtained material is used in as comparative material A-1. The obtained material is a common type of amine collector for iron ore benefication as described in WO 2012-139985 and acts by removing silica in an inverse flotation process.

A-2: 1-Chloro-3-(dodecylamino)propan-2-ol

[0107] ##STR00018##

[0108] A stirred solution of dodecylamine (200 g, 1.08 mol) in isopropanol (540 mL) is cooled to 15° C. and epichlorohydrin (100 g, 1.08 mol) is added dropwise. The addition rate is adjusted so that the reaction mixture does not exceed 30° C. After complete addition, the reaction mixture is stirred for 18 h at ambient temperature and then cooled in an ice bath. The white precipitate is collected by filtration, washed with cold isopropanol and dried under vacuum. 1-Chloro-3-(dodecylamino)propan-2-ol (116 g, 38%/depicted as compound (201)/CAS-No. 1191-55-5) is obtained as a white solid.

[0109] .sup.1H-NMR (500 MHz) and .sup.13C-NMR (125 MHz) spectra of the white solid are measured in CDCl.sub.3. FIG. 1 and FIG. 2 depict the .sup.1H-NMR spectra. FIG. 3 depicts the .sup.13C-NMR spectrum.

A-3: 1-((2-aminoethyl)amino)-3-(dodecylamino)propan-2-ol

[0110] ##STR00019##

[0111] Material obtained from A-2 (100 g, 0.36 mol calculated based on 1-chloro-3-(dodecylamino)propan-2-ol) and ethane-1,2-diamine (108 g, 1.80 mol) are dissolved in ethanol (800 mL). A solution of sodium methylate in methanol (25.3 weight-%, 81.3 g, 0.38 mol) is added dropwise at ambient temperature and the mixture is stirred overnight. The obtained suspension is filtered and the filter cake is washed with ethanol. The combined filtrates are concentrated under reduced pressure and the residue is dried under vaccuum (95° C., 15 mbar) to obtain a material consisting mainly of 1-((2-aminoethyl)amino)-3-(dodecylamino)propan-2-ol (97.8 g, 90% calculated based on 1-((2-aminoethyl)amino)-3-(dodecylamino)propan-2-ol/depicted as compound (101)) as a white solid.

[0112] .sup.1H-NMR (500 MHz) and .sup.13C-NMR spectra (125 MHz) of the white solid are measured in CDCl.sub.3. FIG. 4 depicts the .sup.1H-NMR spectra. FIG. 5 depicts the .sup.13C-NMR spectrum.

A-4: 1-((3-aminopropyl)amino)-3-(dodecylamino)propan-2-ol

[0113] ##STR00020##

[0114] Material obtained from A-2 (100 g, 0.36 mol calculated based on 1-chloro-3-(dodecylamino)propan-2-ol) and propane-1,3-diamine (133 g, 1.79 mol) are dissolved in ethanol (800 mL). A solution of sodium methylate in methanol (25.3 weight-%, 81.3 g, 0.38 mol) is added dropwise at ambient temperature and the mixture is stirred overnight. The obtained suspension is filtered and the filter cake is washed with ethanol. The combined filtrates are concentrated under reduced pressure and the residue is dried under vaccuum (95° C., 15 mbar) to obtain a product consisting mainly of 1-((3-aminopropyl)amino)-3-(dodecylamino)propan-2-ol (102 g, 90% calculated based on 1-((3-aminopropyl)amino)-3-(dodecylamino)propan-2-ol/depicted as compound (102)) as a white solid.

[0115] .sup.1H-NMR (500 MHz) and .sup.13C-NMR (125 MHz) spectra of the white solid are measured in CDCl.sub.3. FIG. 6 and FIG. 7 depict the .sup.1H-NMR spectra. FIG. 8 depicts the .sup.13C-NMR spectrum.

[0116] B) Flotation

[0117] The following examples illustrate further the invention without limiting it. Percentage values are percentage by weight if not stated differently.

[0118] 500 g of ore (hematite based, 63% Fe.sub.2O.sub.3[44% Fe atom], 34% SiO.sub.2), which is ground to such a particle size that 80% passes 100 m (measured by standard dry sieving), is placed in a 1.5 flotation cell of a Denver D10 flotation machine. 500 mL of distilled water is added at ambient temperature (˜21° C.), which results in the formation of a 50% solids. This pulp is conditioned with pregelatinized corn starch in an amount of 1000 g/t (calculated based on ton of dry ore) calculated as dry starch for 3 minutes at 1000 rpm. Afterwards, the pH is adjusted to 9.5 with aqueous 5% sodium hydroxide solution. A collector as stated in table B-1 in an amount of 70 g/t (calculated based on ton of dry ore) is added in form of a 1% aqueous solution, which is prepared with distilled water. The pH is adjusted to 10.5 with aqueous 5% sodium hydroxide solution and the pulp is further conditioned for 1 minute under the same rotation. After conditioning, the vessel volume is filled with distilled water until 2 cm below the lip level under a rotation of 1000 rpm. The pH is again adjusted to 10.5 with aqueous 5% sodium hydroxide solution. Afterwards, the aeration is opened and the froth is collected in a 2 L tray until complete exhaustion. The collected and solids-bearing froth in the tray and the remaining cell fraction are separately dewatered, dried and weighed. Fe— and SiO.sub.2-content of both are analyzed by EDXRF measurement on a lithium borate based fused bead. The results are listed in table B-1.

TABLE-US-00001 TABLE B-1 Fe conc. grade .sup.c) SiO.sub.2 conc. Fe recovery .sup.e) [Fe atom grade .sup.d) [Fe atom SiO.sub.2 weight in per- [SiO.sub.2 weight weight in per- loss .sup.f) example collector cent] in percent] cent] [%] B-1 .sup.a) A-1 70 1.2 91.5 97.9 B-2 .sup.b) A-3 70 1.4 93.5 96.6 B-3 .sup.b) A-4 69 1.8 93.8 97.9 Food notes: .sup.a) comparative .sup.b) according to invention .sup.c) Fe conc. grade means Fe atom content in cell fraction .sup.d) SiO.sub.2 conc. grade means SiO.sub.2 content in cell fraction .sup.e) recovery is the ratio between the overall amount of Fe atom contained in the cell fraction and the overall amount of Fe atom contained in the ore employed as starting material .sup.f) SiO.sub.2 loss is the amount of SiO.sub.2 removed from the cell fraction and expressed in percentage based on the amount of SiO.sub.2 contained in the ore employed as starting material

[0119] The results in table B-1 shows that a targeted concentrate grade of <2.0% SiO.sub.2 and >67% Fe is met for B-1, B-2 and B-3. At this desired grade, the examples B-2 and B-3 provide a higher recovery of valuable iron ore concentrate.