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PROCESS TO TREAT PHOSPHATE ORES

20200222914 · 2020-07-16

    Inventors

    Cpc classification

    International classification

    Abstract

    The present invention relates to a process for treating non-sulfidic ores with a collector composition containing a primary and a secondary collector, wherein the primary collector is selected from the group of amphoteric and anionic surface active compounds and the secondary collector is an ethoxylated fatty acid wherein the average degree of ethoxylation is higher than 0 and less than 2, to collector compositions suitable for use in the above process, and to pulp comprising such collector compositions.

    Claims

    1. Process for treating non-sulfidic ores with a collector composition containing a primary and a secondary collector, containing between 3 and 60 wt % of secondary collector and between 40 and 97 wt % of primary collector, the wt % being based on total collector components, wherein the primary collector is selected from the group of amphoteric and anionic surface-active compounds and the secondary collector is an ethoxylated fatty acid wherein the average degree of ethoxylation is higher than 0 and less than 2.

    2. Process of claim 1, wherein the ethoxylated fatty acid is of the formula
    RC(O)O-(EO)n(I), wherein R is an alkyl or alkenyl group having 7 to 23 carbon atoms and EO is an ethyleneoxy unit; n is a number of higher than 0.5 and less than 2.

    3. Process of claim 2, wherein R is a hydrocarbyl group having 11 to 21 carbon atoms, can be linear or branched, contain 0 to 4 double bonds and may be substituted with up to 3 hydroxyl substituents.

    4. Process of claim 1, wherein the primary collector is an anionic surfactant selected from the group of fatty acids, alkyl benzene sulfonates, alkyl phosphates, alkyl sulfates, alkyl sulfosuccinamates, alkyl sulfosuccinates, alkyl lactylates, alkyl hydroxamates, N-acyl neutral amino acid, like N-acyl derivatives of sarcosine or N-acyl derivatives of glycine, or mixtures thereof.

    5. Process of claim 1, wherein the primary collector is an amphoteric surfactant of the following formula ##STR00003## wherein R is a hydrocarbon group having from 7 to 24 carbon atoms, and preferably from 10 to 18 carbon atoms; A is an oxyalkylene group having from 2 to 4 carbon atoms; R1 is selected from the group consisting of hydrogen and hydrocarbon groups having from 1 to 4 carbon atoms; Y.sup. is selected from the group consisting of COO.sup. and SO3.sup.; n is a number from 0 to 1; p is a number from 0 to about 5; and q is a number from 1 to 2.

    6. Process of claim 1, wherein more than one primary collector is used.

    7. Process of claim 1, wherein the ore is phosphate ore, preferably apatite ore.

    8. Process of claim 1, wherein the process is a direct flotation process.

    9. A process comprising the following steps: a) conditioning a pulped ore, wherein the ore comprises a non-sulfidic mineral, such as phosphate, and optionally flotation bath adjuncts, in an aqueous solution b) adding the collector composition as described in claim 1 b) optionally adding other flotation bath adjuncts or depressants to the pulp, and c) performing a froth flotation process to recover the mineral.

    10. A pulp comprising the crushed and ground non-sulfidic ore, such as phosphate, and a collector composition containing between 3 and 60 wt % of secondary collector and between 40 and 97 wt % of primary collector, the wt % being based on total collector components, wherein the primary collector is selected from the group of amphoteric and anionic surface-active compounds or mixtures thereof and the secondary collector is an ethoxylated fatty acid wherein the average degree of ethoxylation is higher than 0 and less than 2.

    11-15. (canceled)

    Description

    EXAMPLE 1 AND COMPARATIVE EXAMPLES 2 AND 3

    [0037] A phosphate ore containing 25-30% of apatite, 24-28% of silicates and ca 20% of iron oxides was crushed and ground to a desirable flotation size (K80=180 m). 500 g of the ore was placed into a 1.4 L Denver flotation cell, 500 ml of tap water (Stenungsund municipal water with hardness 4 dH) was added and the mixing started. Then 5 minutes conditioning with 25 ml of a 1 wt % aqueous starch solution was performed, the collector was added as a 1 wt % solution, and conditioning was continued for 2.5 minutes.

    [0038] In Example 1 according to the invention the primary collector is an alkyl amido sarcosinate compound ex Croda sold under the tradename Crodacinic 0 combined with tall oil fatty acid (TOFA), and an ethoxylated tall oil fatty acid obtained by ethoxylating tall oil fatty acid with 1 molar equivalent of ethylene oxide is added as secondary collector. In Examples 2 and 3, which are comparative, the collector composition instead of tall oil contains fatty acid ethoxylated with 1 molar equivalent of ethylene oxide, the same tall oil fatty acid ethoxylated with 10 equivalents of ethylene oxide as a secondary collector, or no secondary collector. The compositions are summarized in Table 1 below.

    TABLE-US-00001 TABLE 1 Composition of collector mixtures used in the flotations Amount of flotation aids in the collector mixture, weight % Crodacinic TOFA O TOFA + 1EO TOFA + 10EO Example 1 40 40 20 Comparative 40 40 20 Example 2 Comparative 50 50 Example 3

    [0039] After the conditioning steps tap water was added, so that a total volume of 1.4 L was obtained, the pH of the flotation mixture was adjusted to 9.5 with a 5% NaOH aqueous solution, and the flotation was started. The experiment was performed at RT (201 C.). The rougher flotation, followed by one cleaning step, was performed. All fractions (tailings, middlings and concentrate) were collected and analyzed. The results are summarized in Tables 2 and 3 below. In FIG. 1 the flotation steps performed and the different fractions collected are illustrated schematically.

    [0040] Results

    TABLE-US-00002 TABLE 2 Flotation results presented as P.sub.2O.sub.5 recovery and grade. Collector Amount of phosphate as P.sub.2O.sub.5 composition Fraction grade, % recovery, % Example 1 Rougher tailings 26.62 90.4 Middlings 31.69 84.7 concentrate 34.29 78.4 Comparative Rougher tailings 27.54 88.8 Example 2 Middlings 32.57 82.7 concentrate 34.92 75.1 Comparative Rougher tailings 24.84 91.2 Example 3 Middlings 29.48 86.6 concentrate 32.15 81.7

    TABLE-US-00003 TABLE 3 selectivity factor at grade Collector Selectivity factor at grade composition 27.6% of P.sub.2O.sub.5 29.8% P.sub.2O.sub.5 Example 1 4.9 3.2 Comparative 4.5 3.2 Example 2 Comparative 4.0 2.2 Example 3

    [0041] The selectivity factor is calculated according to the following equation:

    [00001] Selectivity .Math. .Math. factor = reduction .Math. .Math. of .Math. .Math. waste .Math. .Math. ( % ) 100 - recovery .Math. .Math. of .Math. .Math. apatite .Math. .Math. ( % ) , .Math. Where Reduction .Math. .Math. of .Math. .Math. waste .Math. .Math. ( % ) = waste .Math. .Math. in .Math. .Math. fraction .Math. .Math. ( % ) waste .Math. .Math. in .Math. .Math. the .Math. .Math. feed .Math. .Math. ( % ) * 100

    [0042] The selectivity factor should be as high as possible, which is clearly the case for Example 1 according to the present invention over the scope of several P.sub.2O.sub.5 grades. Accordingly, using a fatty acid having a low degree of ethoxylation in line with the present invention as a secondary collector proves advantageous for the selectivity in a phosphate flotation process compared to using a secondary collector that has a higher degree of ethoxylation or no secondary collector.

    EXAMPLE 4 AND COMPARATIVE EXAMPLES 5

    [0043] A phosphate ore containing 25-30% of apatite, 24-28% of silicates and ca 20% of iron oxides was crushed and ground to a desirable flotation size (K80=180 m). 500 g of the ore was placed into a 1.4 L Denver flotation cell, 500 ml of tap water (Stenungsund municipal water with hardness 4 dH) was added and the mixing started. Then 5 minutes conditioning with 25 ml of a 1 wt % aqueous starch solution was performed, the collector was added as a 1 wt % solution, and conditioning was continued for 2.5 minutes.

    [0044] In Example 4 according to the invention the primary collector is an alkyl amido glycinate compound prepared according to WO2015/000931 combined with tall oil fatty acid (TOFA), and an ethoxylated tall oil fatty acid obtained by ethoxylating tall oil fatty acid with 1 molar equivalent of ethylene oxide is added as secondary collector. In Example 5 which is comparative, the collector composition contains no secondary collector. The compositions are summarized in Table 4 below.

    TABLE-US-00004 TABLE 4 Composition of collector mixtures used in the flotations Amount of flotation aids in the collector mixture, weight % TOFA alkyl amido glycinate TOFA + 1EO Example 4 40 40 20 Comparative 50 50 Example 5

    [0045] After the conditioning steps tap water was added so that a total volume of 1.4 L was obtained, the pH of the flotation mixture was adjusted to 9.5 with a 5% NaOH aqueous solution, and the flotation was started. The experiment was performed at RT (201 C.). The rougher flotation, followed by one cleaning step, was performed. All fractions (tailings, middlings and concentrate) were collected and analyzed. The results are summarized in Tables 5 and 6 below. In FIG. 1 the flotation steps performed and the different fractions collected are illustrated schematically.

    [0046] Results

    TABLE-US-00005 TABLE 5 Flotation results presented as P.sub.2O.sub.5 recovery and grade. Amount of phosphate as Recovery at Collector P.sub.2O.sub.5 grade 33% of composition Fraction grade, % recovery, % P2O5, % Example 4 Rougher 26.68 92.5 80 tailings Middlings 31.97 84.7 concentrate 34.59 73.3 Comparative Rougher 26.04 92.9 78 Example 5 tailings Middlings 31.13 86.3 concentrate 33.5 77

    TABLE-US-00006 TABLE 6 selectivity factor at grade Collector Selectivity factor at grade 31% composition of P2O5 Example 4 2.5 Comparative 2.0 Example 5