Environment-friendly composite flotation agent and application

Abstract

The invention belongs to the technical field of mineral separation, and particularly relates to an environment-friendly composite flotation agent and application, and the composite flotation agent comprises the following raw materials in percentage by mass: 36.0%-37.5% of oleic acid, 8%-9% of linoleic acid, 1%-2.5% of linolenic acid, 20%-22% of a surfactant, 0.5%-0.7% of an inhibitor, 1%-2% of tributyl citrate and the balance of a solvent. The prepared composite flotation agent is beneficial to flotation separation of gangue minerals and tungsten ores, has a good flotation effect on low-grade tungsten ores, and is green and environmentally friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing, and particularly relates to an environmentally friendly composite flotation agent and its application. Background Art

[0002] Patent CN108480055B discloses a scheelite flotation collector and its preparation method. The collector comprises the following components, by weight: 40-60 parts of a sulfonated unsaturated fatty acid, 10-20 parts of a hydroxy fatty acid, 5-10 parts of a hydroxamic acid, 5-10 parts of a diesel fuel, and 5-10 parts of a frother. The scheelite flotation collector of the present invention is used for scheelite flotation and exhibits excellent low-temperature resistance, selectivity, and collection capacity, enabling the production of high-grade, high-recovery scheelite concentrate. The scheelite flotation collector produced by this invention exhibits excellent solubility, strong collection capacity, selectivity, and low-temperature resistance, effectively improving mineral processing technical indicators and achieving significant economic benefits. It has promising market prospects, however, as diesel fuel is difficult to degrade and can easily pollute the environment.

[0003] Patent CN114522806B discloses a composite flotation collector, its application, and a method for flotation of scheelite. The composite flotation collector comprises a chelating collector, an oleic acid, sodium hexametaphosphate, and sodium silicate. The weight ratio of the chelating collector, oleic acid, sodium hexametaphosphate, and sodium silicate is 50:5-7.5:2-5:150-200. This composite flotation collector improves the collector's capture capacity and selectivity for the target mineral, meeting the required flotation performance. It also reduces the amount of sodium silicate used in flotation, thereby mitigating the impact of large amounts of sodium silicate as a depressant on tailings sedimentation. Furthermore, FeCl3, oleic acid, and sodium hexametaphosphate are low-cost and environmentally friendly. While this patent improves environmental friendliness, the actual biodegradability of sodium hexametaphosphate is poor, and long-term use can easily lead to phosphate enrichment in water bodies.

[0004] Therefore, there is an urgent need for a green, environmentally friendly, and effective flotation agent on the market. Summary of the Invention

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a composite flotation agent, which is not only green and environmentally friendly, but also can significantly improve the floatability difference between gangue minerals and tungsten minerals, thereby facilitating the flotation separation of gangue minerals and tungsten ores, and has a good flotation effect on low-grade tungsten ores.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention provides an environmentally friendly composite flotation agent, which comprises the following raw materials, calculated by weight percentage: 36.0%-37.5% of oleic acid, 8%-9% of linoleic acid, 1%-2.5% of linolenic acid, 20%-22% of surfactant, 0.5%-0.7% of inhibitor, 1%-2% of tributyl citrate, and the balance being solvent.

[0008] In some embodiments, the surfactant is a composition of alkyl glycoside, α-olefin sulfonate and lauryl alcohol polyoxyethylene ether, and the mass ratio of the three is (0.05-0.1): (0.05-0.12):1.

[0009] The present invention optimizes the compounding of specific surfactants. The hydrophilic glycoside group and the hydrophobic alkyl chain structure can be directionally adsorbed on the mineral-water interface, reducing surface energy and promoting the adhesion of bubbles to target mineral particles. The anionic characteristics of the α-olefin sulfonate give it excellent wettability and dispersibility, preventing mineral particle agglomeration through electrostatic repulsion. At the same time, mixed micelles are formed with the alkyl glycoside, further optimizing the gas-liquid interfacial tension. The lauryl alcohol polyoxyethylene ether can adjust the interfacial film strength, enhance the bubble stability, and synergistically improve the mineral carrying capacity of the flotation foam with the α-olefin sulfonate. The present invention further limits the ratio of the alkyl glycoside, the α-olefin sulfonate and the lauryl alcohol polyoxyethylene ether, and can achieve selectivity through differential adsorption of polar groups. The glycoside structure of the alkyl glycoside is preferentially adsorbed on the surface of oxygen-containing minerals, the sulfonic acid group of the α-olefin sulfonate targets metal oxides, and the ether bond of the lauryl alcohol polyoxyethylene ether and the hydrophobic chain strengthen the hydrophobic effect, synergistically improving the capture efficiency of the target mineral, inhibiting the floating of gangue, and enhancing the recovery rate of the mineral.

[0010] In some embodiments, the inhibitor is modified starch.

[0011] In some embodiments, the method for preparing the modified starch comprises the following steps:

[0012] (1) Add N-acetylglycine to DMF, stir at 0-5°C for 20-30 minutes, then add anhydrous potassium carbonate, stir for 3-6 minutes, then add propylene bromide dropwise, continue stirring for 25-35 minutes, then heat to 30-35°C, react for 47-49 hours, column chromatography, and dry to obtain compound 1;

[0013] (2) Compound 1 obtained in step (1) and lauroyl chloride were added to ethanol, and triethylamine was added in batches at 2-8°C, and the reaction was continued for 10-12 hours to obtain compound 2;

[0014] (3) adding starch, acrylic acid and sulfuric acid to tetrahydrofuran, reacting at 60-70° C. for 5-6 hours, filtering, washing and drying to obtain pretreated starch;

[0015] (4) The pretreated starch obtained in step (3), compound 2 obtained in step (2), and an initiator are added to ethanol, reacted at 60-70° C. for 1-2 hours, and then epichlorohydrin is added and the reaction is continued for 1-2 hours to obtain modified starch.

[0016] The starch used in traditional flotation agents is mostly natural starch or simply oxidized starch, which has weak adsorption capacity and poor selectivity, and is easily inactivated under acidic or high temperature conditions. The present invention, by modifying starch, enables it to have selective adsorption, foam stability control and environmental compatibility during the mineral flotation process. The possible reason is that hydrophobic segments are added to the modified starch. The hydrophobic segments can preferentially adsorb on silicon-containing gangue minerals, while the anionic groups can be targeted and adsorbed on the surface of metal oxide minerals through electrostatic effects. This "dual-functional adsorption mechanism" significantly improves mineral separation efficiency and improves ore grade. In addition, epichlorohydrin is used as a cross-linking agent to form a three-dimensional network structure, which significantly improves the thermal stability and shear resistance of starch, avoids degradation caused by mechanical agitation during the flotation process, and the product has no phosphorus residue, which is more environmentally friendly. In addition, epichlorohydrin can be lightly cross-linked with surfactants to form a micellar network, further enhancing foam stability.

[0017] In some embodiments, the mass ratio of N-acetylglycine to allyl bromide in step (1) is 1:(0.2-0.5).

[0018] In some embodiments, the mass ratio of starch to acrylic acid in step (3) is 1:(0.5-1).

[0019] In some embodiments, the mass ratio of the pretreated starch to compound 2 in step (4) is 1:(0.1-0.4).

[0020] In some embodiments, the mass ratio of the pretreated starch to epichlorohydrin in step (4) is 1:(0.02-0.08).

[0021] The second invention of the present invention provides an application of an environmentally friendly composite flotation agent, comprising the following steps:

[0022] S1. Grind and sieve the raw ore, add water to adjust the tungsten ore content to 25-35 wt%, and add sodium hydroxide to adjust the pH to 8-9 to obtain a slurry;

[0023] S2. Add an inhibitor to the slurry obtained in step S1 and stir for 5-10 minutes. Then add oleic acid, linoleic acid, and linolenic acid and stir for 10-15 minutes. Finally, add a surfactant, tributyl citrate, and a solvent and continue stirring for 5-10 minutes. After aeration and bubbling, flotation and scraping are performed at room temperature. The foam product is the concentrate.

[0024] In some embodiments, the total amount of the flotation agent is 300-600 g / t of raw ore.

[0025] In some embodiments, the flotation scraping time is 5-8 minutes, and the frequency is 30-40 times / min.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention prepares an environmentally friendly composite flotation agent by using oleic acid, linoleic acid, linolenic acid, surfactants, inhibitors and other additives. The dosage of the agent is small, green and environmentally friendly, has a good flotation effect on low-grade tungsten ore, and can significantly improve the grade and recovery rate of tungsten ore.

[0028] 2. The present invention reduces surface energy, promotes the adhesion of bubbles to target mineral particles, enhances bubble stability, improves the capture rate of target minerals, inhibits the floating of gangue, and enhances the recovery rate of minerals by compounding specific surfactants such as alkyl glycosides, α-olefin sulfonates, and lauryl alcohol polyoxyethylene ether.

[0029] 3 The present invention modifies starch to make it have both inhibitory and dispersing functions. It can selectively adsorb and have compatibility during the mineral flotation process, thereby enhancing the selective inhibition of gangue minerals, solving the problem of difficult separation of tungsten ore and gangue minerals, and solving the problem of easy degradation of ordinary starch in the flotation process and low tungsten ore recovery rate. DETAILED DESCRIPTION

[0030] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following examples and comparative examples are intended only to illustrate the present invention and are not intended to limit the present invention. Other combinations and various modifications within the scope of the present invention may be made without departing from the spirit or scope of the present invention.

[0031] To facilitate those skilled in the art in practicing the present invention, some of the raw materials and manufacturers of the examples and comparative examples are described as follows: oleic acid CAS: 112-80-1; linoleic acid CAS: 60-33-3; linolenic acid CAS: 463-40-1; the starch used is corn starch; the model of the alkyl glycoside is Glucopon 225DK (BASF); sodium α-olefin sulfonate CAS: 68439-57-6 is purchased from Jinan Duanxing Chemical Technology Co., Ltd.; the model of lauryl alcohol polyoxyethylene ether is AEO-9, purchased from Sunda Chemical (Nantong) Co., Ltd.

[0032] Other compounds and related reagents used can be purchased from the market.

[0033] Preparation Example 1

[0034] The preparation method of modified starch-1 comprises the following steps:

[0035] (1) 10 g of N-acetylglycine was added to 500 ml of DMF and stirred at 2°C for 25 min. Then, 1 g of anhydrous potassium carbonate was added and stirred for 5 min. Then, 4 g of propylene bromide was added dropwise and stirred for 30 min. The temperature was then raised to 32°C and the reaction was continued for 48 h. The mixture was purified by column chromatography and dried to obtain compound 1.

[0036] (2) 10 g of compound 1 obtained in step (1) and 14 g of lauroyl chloride were added to 200 ml of anhydrous dichloromethane, and 5 g of triethylamine was added in two equal batches at 5° C. The reaction was continued for 11 h, and the mixture was subjected to column chromatography and dried to obtain compound 2;

[0037] (3) adding 10 g corn starch, 7 g acrylic acid, and 1 g 85 wt% sulfuric acid to 200 ml tetrahydrofuran, reacting at 65° C. for 5.5 h, filtering, washing, and drying to obtain pretreated starch;

[0038] (4) 10 g of the pretreated starch obtained in step (3), 3 g of compound 2 obtained in step (2), and 0.1 g of azobisisobutyronitrile were added to 100 ml of anhydrous ethanol, and the mixture was reacted at 65° C. for 1.5 h. Then, 0.5 g of epichlorohydrin was added and the reaction was continued for 1.5 h to obtain modified starch-1.

[0039] Preparation Example 2

[0040] The preparation method of modified starch-2 is the same as that of Preparation Example 1, except that the amount of bromopropylene added in step (1) is 12 g.

[0041] Preparation Example 3

[0042] The preparation method of modified starch-3 is the same as that of Preparation Example 1, except that the amount of compound 2 added in step (4) is 5 g.

[0043] Preparation Example 4

[0044] The preparation method of modified starch-4 is the same as that of Preparation Example 1, except that the amount of epichlorohydrin added in step (4) is 1 g.

[0045] Example 1

[0046] An environmentally friendly composite flotation agent comprises the following raw materials, calculated by weight percentage: 37% oleic acid, 8.5% linoleic acid, 2% linolenic acid, 21% surfactant, 0.6% modified starch-1, 1.5% tributyl citrate, and the balance is water.

[0047] The surfactant is a composition of alkyl glycoside, sodium α-olefin sulfonate and lauryl alcohol polyoxyethylene ether, and the mass ratio of the three is 0.08:0.08:1.

[0048] Example 2

[0049] An environmentally friendly composite flotation agent comprises the following raw materials, calculated by weight percentage: 36.0% oleic acid, 8% linoleic acid, 1% linolenic acid, 20% surfactant, 0.5% modified starch-1, 1% tributyl citrate, and the balance being water.

[0050] The surfactant is a composition of alkyl glycoside, sodium α-olefin sulfonate and lauryl alcohol polyoxyethylene ether, and the mass ratio of the three is 0.05:0.05:1.

[0051] Example 3

[0052] An environmentally friendly composite flotation agent comprises the following raw materials, calculated by weight percentage: 37.5% oleic acid, 9% linoleic acid, 2.5% linolenic acid, 22% surfactant, 0.7% modified starch-1, 2% tributyl citrate, and the balance is water.

[0053] The surfactant is a composition of alkyl glycoside, sodium α-olefin sulfonate and lauryl alcohol polyoxyethylene ether, and the mass ratio of the three is 0.1:0.12:1.

[0054] Example 4

[0055] An environmentally friendly composite flotation agent, the specific implementation method is the same as that of Example 1, except that an equal amount of modified starch-1 is replaced by modified starch-2.

[0056] Example 5

[0057] An environmentally friendly composite flotation agent, the specific implementation manner is the same as that of Example 1, except that an equal amount of modified starch-1 is replaced by modified starch-3.

[0058] Example 6

[0059] An environmentally friendly composite flotation agent, the specific implementation manner is the same as that of Example 1, except that an equal amount of modified starch-1 is replaced by modified starch-4.

[0060] Example 7

[0061] An environmentally friendly composite flotation agent, the specific implementation method is the same as that of Example 1, except that an equal amount of modified starch-1 is replaced by starch.

[0062] Example 8

[0063] An environmentally friendly composite flotation agent, the specific implementation manner is the same as that of Example 1, except that the mass ratio of the composition of alkyl glycoside, sodium α-olefin sulfonate and lauryl alcohol polyoxyethylene ether is 0.12:0.08:1.

[0064] Performance Testing

[0065] The composite flotation agents of each embodiment were applied to a low-grade scheelite for flotation test. The WO grade of the ore was 0.39%, and the total amount of flotation agent was 500 g / t of ore. The specific steps were as follows:

[0066] S1. Grind 1000 g of raw ore through a 200-mesh sieve, add water to adjust the tungsten ore content to 30 wt%, and add sodium hydroxide to adjust the pH to 9 to obtain a slurry;

[0067] S2, step S1 to obtain slurry, add modified starch, stir 8min, then add oleic acid, linoleic acid, linolenic acid, stir 13min, finally add surfactant and tributyl citrate and water and continue stirring for 8min, after inflation bubbling, flotation scraping foam at a frequency of 35 times / min for 7min under normal temperature conditions, filter the foam product, dry to obtain concentrate. Detect the grade of WO3 in tungsten ore after primary flotation and calculate the recovery of WO3.

[0068] The test results are shown in Table 1.

[0069] Table 1

[0070] Group grade% Recovery rate (%) Example 1 10.98 89.74 Example 2 10.94 89.67 Example 3 10.97 89.72 Example 4 8.77 81.34 Example 5 9.05 83.68 Example 6 10.15 85.34 Example 7 8.02 77.69 Example 8 8.31 79.22

[0071] From the comparison of the experimental data of Examples 1-3 in Table 1, it can be seen that the composite flotation agent can improve the grade and recovery rate of tungsten ore; compared with Example 1, Examples 4 and 5 show that the ratio of N-acetylglycine to propylene bromide and the ratio of pretreated starch to compound 2 are changed, which may lead to the weakening of the electrostatic repulsion with the gangue powder, the floating of the gangue, and the reduction of the grade and recovery rate of the tungsten ore; compared with Example 1, Example 6 shows that the change in the ratio of pretreated starch to epichlorohydrin may lead to excessive cross-linking of the two, the weakening of the inhibitory effect of the modified starch, and the decrease of the grade and recovery rate of the tungsten ore, which may lead to the reduction of the grade and recovery rate of the tungsten ore; compared with Example 1, Example 7 shows that the use of conventional starch has weak adsorption capacity and poor selectivity, and the grade and recovery rate of the tungsten ore are reduced; compared with Example 1, Example 8 shows that the change in the ratio of surfactant leads to a change in selective adsorption, and the grade and recovery rate of the tungsten ore are reduced.

[0072] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An environmentally friendly composite flotation agent, characterized in that: The invention comprises the following raw materials based on 100% by mass: 36.0%-37.5% of oleic acid, 8%-9% of linoleic acid, 1-2.5% of linolenic acid, 20%-22% of surfactant, 0.5%-0.7% of inhibitor, 1%-2% of tributyl citrate, and the balance is solvent.

2. The environmentally friendly composite flotation agent according to claim 1, characterized in that: The surfactant is a composition of alkyl glucoside, α-olefin sulfonate and lauryl alcohol polyoxyethylene ether, and the mass ratio of the three is (0.05-0.1): (0.05-0.12):

1.

3. The environmentally friendly composite flotation agent according to claim 1, characterized in that: The inhibitor is modified starch.

4. The environmentally friendly composite flotation agent according to claim 3, characterized in that: The preparation method of the modified starch comprises the following steps: (1) Add N-acetylglycine to DMF, stir at 0-5°C for 20-30 minutes, then add anhydrous potassium carbonate, stir for 3-6 minutes, then add propylene bromide dropwise, continue stirring for 25-35 minutes, then heat to 30-35°C, react for 47-49 hours, column chromatography, and dry to obtain compound 1; (2) Compound 1 obtained in step (1) and lauroyl chloride were added to dichloromethane, and triethylamine was added in batches at 2-8°C. The reaction was continued for 10-12 hours, column chromatography was performed, and the mixture was dried to obtain compound 2; (3) adding starch, acrylic acid and sulfuric acid to tetrahydrofuran, reacting at 60-70° C. for 5-6 hours, filtering, washing and drying to obtain pretreated starch; (4) The pretreated starch obtained in step (3), compound 2 obtained in step (2), and an initiator are added to ethanol, reacted at 60-70° C. for 1-2 hours, and then epichlorohydrin is added and the reaction is continued for 1-2 hours to obtain modified starch.

5. The environmentally friendly composite flotation agent according to claim 4, characterized in that: The mass ratio of N-acetylglycine to propylene bromide in step (1) is 1:(0.2-0.5).

6. The environmentally friendly composite flotation agent according to claim 4, characterized in that: The mass ratio of the pretreated starch to compound 2 in step (4) is 1:(0.1-0.4).

7. The environmentally friendly composite flotation agent according to claim 4, characterized in that: The mass ratio of the pretreated starch to epichlorohydrin in step (4) is 1:(0.02-0.08).

8. Use of the environmentally friendly composite flotation agent according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Grind and sieve the raw ore, add water to adjust the tungsten ore content to 25-35 wt%, and add sodium hydroxide to adjust the pH to 8-9 to obtain a slurry; S2. Add an inhibitor to the slurry obtained in step S1 and stir for 5-10 minutes. Then add oleic acid, linoleic acid, and linolenic acid and stir for 10-15 minutes. Finally, add a surfactant, tributyl citrate, and a solvent and continue stirring for 5-10 minutes. After aeration and bubbling, flotation and scraping are performed at room temperature. The foam product is filtered and dried to obtain a concentrate.

9. The use of the environmentally friendly composite flotation agent according to claim 8, characterized in that: The total amount of the flotation agent is 300-600g / t of raw ore.

10. The use of the environmentally friendly composite flotation agent according to claim 8, characterized in that: The flotation scraping time is 5-8 minutes, and the frequency is 30-40 times / min.