Method For Flotation Of A Phosphate-Containing Ore

Abstract

The invention relates to a method for manufacturing a concentrate enriched in a phosphate mineral content from an ore, which contains a phosphate mineral and a non-phosphate mineral, by a flotation, which method comprises the step of adding a surfactant system comprising (A) a fatty acid, (B) a blend of ethoxylated and non-ethoxylated alcohols, which is obtainable by blending (i) a reaction product of a first C.sub.12-C.sub.16 aliphatic alcohol having an average degree of branching of 1.9 to 3.5 and 10 to 20 equivalents of ethylene oxide, and (ii) a second C.sub.12-C.sub.16 aliphatic alcohol having an average degree of branching of 1.9 to 3.5, wherein the amount of (i) is 80 to 95 wt. % and the amount of (ii) is 5 to 20 wt. % and wt. % is based on the overall weight of the mixture of ethoxylated and non-ethoxylated alcohols, to a prepared aqueous pulp of the ore and optionally one or more flotation auxiliaries to obtain an aqueous mixture. Furthermore, a use of the surfactant system as flotation collector is disclosed.

Claims

1. A method for manufacturing a concentrate enriched in phosphate mineral content from an ore, wherein the ore contains a phosphate mineral and a nonphosphate mineral, by a flotation, comprising: (c) adding a surfactant system comprising components: (A) a fatty acid, (B) a blend of ethoxylated and non-ethoxylated alcohols, which is obtainable by blending components (i) a reaction product of a first C.sub.12-C.sub.16 aliphatic alcohol having an average degree of branching of 1.9 to 3.5 and 10 to 20 equivalents of ethylene oxide, and (ii) a second C.sub.12-C.sub.16 aliphatic alcohol having an average degree of branching of 1.9 to 3.5, wherein the amount of (i) is about 80 wt. % to about 95 wt. % and the amount of (ii) is about 5 wt. % to about 20 wt. % and wt. % is based on the overall weight of the mixture of ethoxylated and non-ethoxylated alcohols, 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, further comprising: (a) providing the ore, wherein the ore contains the phosphate mineral and the non-phosphate mineral; (b) preparing from the provided ore by addition of water and optionally one or more flotation auxiliaries an aqueous pulp; and (d) aerating the aqueous mixture in a flotation cell to generate a froth, wherein the froth contains the concentrate enriched in phosphate mineral content.

3. The method according to claim 1, wherein the weight ratio between component (A) and component (B) is about 1 to about 3.

4. The method according to claim 1, wherein the amount of (i) is 83 to 93 wt. % and the amount of (ii) is 7 to 17 wt. %.

5. The method according to claim 1, wherein component (i) is a reaction product of the first C.sub.12-C.sub.16 aliphatic alcohol having an average degree of branching of 1.9 to 3.5 and 10 to 14 equivalents of ethylene oxide.

6. The method according to claim 1, wherein the average degree of branching of the first C.sub.12-C.sub.16 aliphatic alcohol is between 2.0 and 2.5.

7. The method according to claim 1, wherein the first C.sub.12-C.sub.16 aliphatic alcohol and the second C.sub.12-C.sub.16 aliphatic alcohol are the same C.sub.12-C.sub.16 aliphatic alcohol.

8. The method according to claim 1, wherein in the blend of ethoxylated and non-ethoxlyated alcohols, the specific ratio between the number of molecules of the sum of the first C.sub.12-C.sub.16 aliphatic alcohol and second C.sub.12-C.sub.16 aliphatic alcohol in relation to the number of molecules of the sum of the first C.sub.12-C.sub.16 aliphatic alcohol, the second C.sub.12-C.sub.16 aliphatic alcohol and ethoxylated first C.sub.12-C.sub.16 alcohols and the number of molecules of the most occurring ethoxylated first C.sub.12-C.sub.16 aliphatic alcohol with the same number of oxyethylene groups in relation to the number of molecules of the sum of the first C.sub.12-C.sub.16 aliphatic alcohol, the second C.sub.12-C.sub.16 aliphatic alcohol and ethoxylated first C.sub.12-C.sub.16 alcohols is above 2.5 and below 6.

9. The method according to claim 1, wherein the first C.sub.12-C.sub.16 aliphatic alcohol is isotridecanol.

10. The method according to claim 1, wherein component (A) is added in an amount between 10 g to 1000 g per ton of the ore.

11. The method according to claim 1, wherein component (B) is added in an amount between 10 g to 500 g per ton of the ore.

12. The method according to claim 1, wherein the pH value at step (c) is between 8 and 11.

13. The method according to claim 1, wherein at step (b) one or more flotation auxiliaries are added and one of the flotation auxiliaries is a depressing agent, a froth regulator, a further anionic surfactant different to component (A), a further nonionic co-collector different to components (i) or (ii) or an extender oil.

14. The method according to claim 13, wherein one of the flotation auxiliaries is a depressing agent, which is sodium silicate.

15. A method of using a surfactant system comprising components (A) a fatty acid, (B) a blend of ethoxylated and non-ethoxylated alcohols, which is obtainable by blending components (i) a reaction product of a first C.sub.12-C.sub.16 aliphatic alcohol having an average degree of branching of 1.9 to 3.5 and 10 to 20 equivalents of ethylene oxide, and (ii) a second C.sub.12-C.sub.16 aliphatic alcohol having an average degree of branching of 1.9 to 3.5, wherein the amount of (i) is about 80 wt. % to about 95 wt. % and the amount of (ii) is about 5 wt. % to about 20 wt. % and wt. % is based on the overall weight of the mixture of ethoxylated and non-ethoxylated alcohols, as a flotation collector for manufacturing a concentrate enriched in phosphate mineral content from an ore, which contains a phosphate mineral and a non-phosphate mineral, by a flotation.

16. A blend of ethoxylated and non-ethoxylated alcohols, comprising a reaction product of: (i) a first C.sub.12-C.sub.16 aliphatic alcohol having an average degree of branching of 1.9 to 3.5 and 10 to 20 equivalents of ethylene oxide, and (ii) a second C.sub.12-C.sub.16 aliphatic alcohol having an average degree of branching of 1.9 to 3.5, wherein the amount of (i) is 80 to 95 wt. % and the amount of (ii) is 5 to 20 wt. % and wt. % is based on the overall weight of the mixture of ethoxylated and non-ethoxylated alcohols.

Description

[0100] FIGS. 1 to 4 are attached and described below.

[0101] FIG. 1 shows a distribution of relative ESI MS signal intensities in percentage on y-axis versus ethoxylation numbers of the phthalic acid mono ester component on x-axis of the derivatized material from A-2 [“iC.sub.13-3EO”].

[0102] FIG. 2 shows a distribution of relative ESI MS signal intensities in percentage on y-axis versus ethoxylation numbers of the phthalic acid mono ester component on x-axis of the derivatized material from A-3 [“iC.sub.13-10EO”].

[0103] FIG. 3 shows a distribution of relative ESI MS signal intensities in percentage on y-axis versus ethoxylation numbers of the phthalic acid mono ester component on x-axis of the derivatized material from A-4 [“0.4 iC.sub.13-3EO+0.6 iC.sub.13-10EO”].

[0104] FIG. 4 shows a distribution of relative ESI MS signal intensities in percentage on y-axis versus ethoxylation numbers of the phthalic acid mono ester component on x-axis of the derivatized material from A-5 [“0.13 iC.sub.13-0EO+0.87 iC.sub.13-10EO”].

[0105] The following examples illustrate further the invention without limiting it. Percentage values are percentage by weight if not stated differently. Part values are parts by weight if not stated differently.

[0106] A) Isotridecanol, its Ethoxylates and Mixtures Thereof

[0107] A-1 (comparative): isotridecanol with an average degree of branching of 2.2 [“iC.sub.13-OEO”], which is obtained by oligomerizing a butene isomer mixture, separating out a trimer fraction and hydroformylating the separated trimer fraction.

[0108] The ethoxylation reaction at A-2 and A-3 is conducted in a pressurized reactor using a double metal cyanide (DMC) catalyst.

[0109] A-2 (comparative): reaction product containing A-1 and isotridecanol ethoxylates obtained by reaction of A-1 with 3 equivalents of ethylene oxide [“iC.sub.13-3EO” ]

[0110] Percentage of molecule numbers of single components are provided as described under B) by transfer.

[0111] Relative intensity of A-1, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.0—OH: 36.2%

[0112] Relative intensity of the most intensive ethoxylated component, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.1—OH:

[0113] 18.1%

[0114] 36.2% divided by 18.1%: 2.0

[0115] A-3 (comparative): reaction product containing A-1 and isotridecanol ethoxylates obtained by reaction of A-1 with 10 equivalents of ethylene oxide [“iC.sub.13-10EO” ]

[0116] Percentage of molecule numbers of single components are provided as described under B) by transfer. [0117] relative intensity of A-1, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.0—OH: 11.6% [0118] relative intensity of the most intensive ethoxylated component, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.5—OH or iC.sub.13—(O—CH.sub.2CH.sub.2)s-OH or iC.sub.13—(O—CH.sub.2CH.sub.2).sub.7—OH: 7.3% [0119] 11.6% divided by 7.3%: 1.6

[0120] A-4 (comparative): blend of 4 parts of A-2 and 6 parts of A-3 obtained by mixing of 4 parts of A2 and 6 parts of A-3 [“0.4 iC.sub.13-3EO+0.6 iC.sub.13-10EO” ]

[0121] Percentage of molecule numbers of single components are provided as described under B) by transfer. [0122] relative intensity of A-1, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.0—OH: 28.7% [0123] relative intensity of the most intensive ethoxylated component, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.1—OH: 14.4% [0124] 28.7% divided by 14.4%: 2.0

[0125] A-5 (according to invention): blend of 1.3 parts of A-1 and 8.7 parts of A-3 obtained by mixing of 1.3 parts of A-1 and 8.7 parts of A-3 [“0.13 iC.sub.13-0EO+0.87 iC.sub.13-10EO” ]

[0126] Percentage of molecule numbers of single components are provided as described under B) by transfer. [0127] relative intensity of A-1, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.0—OH: 23.1% [0128] relative intensity of the most intensive ethoxylated component, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.7—OH: 6.4% [0129] 23.1% divided by 6.4%: 3.6

[0130] B) Mass Spectroscopy of Alcoholic Components

[0131] ESI MS (electro spray ionization mass spectroscopy) analysis of derivatized A-2, A-3, A-4 and A-5 is determined for a quantitative fractional distribution of non-ethoxylated and ethoxylated isotridecanol components. The hydroxyl functional groups of the non-ethoxylated and ethoxylated isotridecanol components are derivatized with phthalic anhydride to overcome the ESI discrimination of the low molecular weight components and the problem of multiple charged formation of the higher molecular weight components of ethoxylated alcohols in the positive ionization mode. A sample is derivatized with a derivatizating solution, which consists of 1 M phthalic anhydride and pyridine in acetonitrile. 50 μL of the sample is added into 1 mL derivatizating solution. Afterwards, this mixture is kept at 100° C. for 2 h. After cooling down to room temperature, 50 μL of the mixture is diluted with 950 μL acetonitrile. An aliquot is injected in a HPLC (high pressure liquid chromatography) MS, equipped with a combination of XSelect HSS PFP (150×3 mm, 3.5 μm) and LiChrospher 100 RP 8 (125×3 mm, 5 μm) (TM Merck) using a water methanol gradient with 0.1% formic acid as modifier. The column oven is set to 50° C. The derivatized components are detected with a high-resolution mass spectrometer using electrospray ionization in negative mode. The resulting carboxylate derivatives iC.sub.13—(O—CH.sub.2CH.sub.2).sub.n—O—(COC.sub.6H.sub.4—COOH) with n=0, 1, 2, . . . are measured in the negative ionization mode without the above-mentioned issues. The derivatization scheme of iC.sub.13(O—CH.sub.2—CH.sub.2).sub.n—OH with n=0, 1, 2, . . . is depicted below

##STR00001##

[0132] The advantage of introducing a negative charge by derivatization is that the response factor for every component of the distribution is the same. Dividing the absolute ESI MS signal intensity for a component by the sum of all absolute ESI MS signal intensities provides a relative ESI MS signal intensity for the component, which is stated as percentage. Accordingly, a relative ESI MS signal intensity for a component correlates to the number of all molecules of the component in relation to the number of all molecules of all components. With a derivatization being quantitative or at least not discriminating between different amounts of ethoxy-units in a molecule, the calculated relative ESI MS signal intensity for the phthalic acid mono ester can be transferred to the correlations of non-derivatized components iC.sub.13—(O—CH.sub.2CH.sub.2).sub.n—OH with n=0, 1, 2, . . . .

[0133] FIG. 1 to FIG. 4 depict distributions of relative ESI MS signal intensities in percentage on y-axis versus ethoxylation numbers of the phthalic acid mono ester components on x-axis of the derivatized material from A-2 to A-5.

[0134] FIG. 1 depicts the ESI MS signal intensities of the phthalic acid mono esters of the alcoholic components of A-2.

[0135] Relative intensity of the phthalic acid mono ester of A-1, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.0—O—(CO—C.sub.6H.sub.4—COOH)):

[0136] 36.2%

[0137] Relative intensity of the most intensive phthalic acid mono ester of an ethoxylated component, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.1—O—(CO—C.sub.6H.sub.4—COOH): 18.1%

[0138] 36.2% divided by 18.1%: 2.0

[0139] FIG. 2 depicts the ESI MS signal intensities of the phthalic acid mono esters of the alcoholic components of A-3 as described under B).

[0140] Relative intensity of the phthalic acid mono ester of A-1, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.0—OH: 11.6%

[0141] Relative intensity of the most intensive phthalic acid mono ester of an ethoxylated component, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.5—O—(CO—C.sub.6H.sub.4—COOH) or iC.sub.13—(O—CH.sub.2CH.sub.2).sub.6—O—(CO—C.sub.6H.sub.4—COOH) or iC.sub.13—(OCH.sub.2CH.sub.2).sub.7—O—(CO—C.sub.6H.sub.4—COOH): 7.3%

[0142] 11.6% divided by 7.3%: 1.6

[0143] FIG. 3 depicts the ESI MS signal intensities of the phthalic acid mono esters of the alcoholic components of A-4 as described under B).

[0144] Relative intensity of the phthalic acid mono ester of A-1, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.0—O—(CO—C.sub.6H.sub.4—COOH):

[0145] 28.7%

[0146] Relative intensity of the most intensive phthalic acid mono ester of an ethoxylated component, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.1—O—(CO—C.sub.6H.sub.4—COOH): 14.4%

[0147] 28.7% divided by 14.4%: 2.0

[0148] FIG. 4 depicts the ESI MS signal intensities of the phthalic acid mono esters of the alcoholic components of A-5 as described under B).

[0149] Relative intensity of the phthalic acid mono ester of A-1, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.0—O—(CO—C.sub.6H.sub.4—COOH):

[0150] 23.1%

[0151] Relative intensity of the most intensive phthalic acid mono ester of an ethoxylated component, i.e. iC.sub.13—(O—CH.sub.2CH.sub.2).sub.7—O—(CO—C.sub.6H.sub.4—COOH): 6.4% 23.1% divided by 6.4%: 3.6

TABLE-US-00001 TABLE B-1 numerical values of A-2 to A-5 at FIG. 1 to FIG. 4 relative intensity [%] ethoxylation A-2 .sup.a) A-3 .sup.a) A-4 .sup.a) A-5 .sup.b) number (FIG. 1) (FIG. 2) (FIG. 3) (FIG. 4) 0 36.2 11.6 28.7 23.1 1 18.1 5.8 14.4 5.0 2 14.4 6.0 11.9 5.2 3 10.5 6.5 9.3 5.7 4 7.2 7.0 7.1 6.1 5 4.8 7.3 5.5 6.3 6 3.1 7.3 4.3 6.3 7 2.0 7.3 3.6 6.4 8 1.4 7.1 3.1 6.2 9 0.9 6.7 2.7 5.8 10 0.6 6.0 2.2 5.2 11 0.4 5.2 1.8 4.5 12 0.2 4.3 1.5 3.7 13 x .sup.c) 3.4 1.1 3.0 14 2.0 0.8 2.3 15 2.0 0.6 1.7 16 1.4 0.4 1.2 17 1.0 0.3 0.8 18 0.6 0.2 0.6 19 0.4 x .sup.c) 0.4 20 0.2 0.2 21 x .sup.c) x .sup.c) Footnotes: .sup.a) comparative .sup.b) according to invention .sup.c) numerical values below 0.2% not listed

[0152] C) flotation

[0153] In a continuous flotation process, apatite is enriched by flotation from an ore feed containing an equivalent of 7.5% P.sub.2O.sub.5 as fluorapatite, and 11% CO.sub.2 as calcite and dolomite, ground to 38% passing a 71 μm sieve (80% passing 200 μm sieve). In the continuous beneficiation process, the ore is being wet ground in a ball mill to the desired size, followed by a wet magnetic separation to remove ferromagnetic components (primarily magnetite Fe.sub.3O.sub.4). The non-magnetic residue is conditioned as an aqueous pulp containing 1000 parts of solids and 1000 parts of water (the approximate ionic content of the water is provided in table C-1) as well as 0.36 parts of sodium carbonate, 0.28 parts of sodium silicate as a depressant, 0.06 parts of a heavy distillation fraction from the industrial manufacturing of 2-ethylhexanol as a froth regulator, 0.15 parts of distilled tall oil fatty acid from northern pine wood as the main collector as well as an amount of a co-collector, i.e. 0.145 parts or 0.128 parts as indicated in table C-2. The distilled tall oil fatty acid and the co-collector are mixed and diluted with water (the approximate ionic content of the water is provided in table C-1) to a concentration of 1.5 wt. % before addition. The ore slurry is subjected to froth flotation in a continuous process consisting of a two rougher stages, two cleaner stages and two scavengers with an average residence time of 4 min. The pH is controlled at 9 by adding sodium carbonate as a solution. The collector and co-collector are primarily added to the rougher stage, although a part of the collector and co-collector addition is diverted to the scavenger stage if needed. Water is circulated in the process (the approximate ionic content of the water is provided in table C-1). The mass throughput of concentrate of the second cleaner stage as well as of the final flotation tailings is determined via ultrasonic mass flow detectors, while the phosphate content is determined by generating a borate fluxed pellet and determining phosphorus content of the pellet from the characteristic X-ray fluorescence signal from which the concentrate grade can be calculated as wt. % (P.sub.2O.sub.5). Data are taken every 3 hours for tailings, concentrate and intermediate fractions. The process control is achieved by a skilled person interpreting the data and changing the collector, co-collector and depressant addition until a steady state is reached. After the process reached the steady state, the data are averaged over a period of 11 days. From these data, an average phosphate recovery is calculated with a reliability far exceeding the data obtained in a single lab scale test, since minor deviations resulting from fluctuations in ore compositions or process parameter variations are averaged out. Results are provided in table C-2.

TABLE-US-00002 TABLE C-1 approximate ionic content of the applied water dissolved suspended carbonates solids solids pH Ca.sup.2+ Mg.sup.2+ including HCO.sub.3.sup.− SO.sub.4.sup.2− Cl.sup.− 740 mg/L 15 mg/L 9 24 mg/L 30 mg/L 350 mg/L 240 mg/L 9 mg/L

TABLE-US-00003 TABLE C-2 flotation with recovery and grade amount of distilled tall co-collector oil fatty acids recovery of [wt. % based [wt. % based P.sub.2O.sub.5 in grade of on dry ore after on dry ore after concentrate concentrate example co-collector magnetic separation] magnetic separation] [%] [wt. % P.sub.2O.sub.5] C-2-1 .sup.a) A-4 0.0145 0.015 76.8 37.1 [“0.4 iC.sub.13-3EO + 0.6 iC.sub.13-10EO”] C-2-2 .sup.b) A-5 0.0128 0.015 77.7 36.9 [“0.13 iC.sub.13-0EO + 0.87 iC.sub.13-10EO”] Footnotes: .sup.a) comparative .sup.b) according to invention

[0154] The results in table C-2 shows at example C-2-2 an increase in average phosphate recovery by 1.1% units versus example C-2-1 at a nearly constant concentrate grade. Furthermore, the amount of co-collector is at the same time reduced by 10% versus example C-2-1.