Coal slime flotation collector, preparation method and application thereof

Abstract

The application discloses a slime flotation collector and a preparation method and application thereof, and belongs to the technical field of slime flotation reagent research and development. The slime flotation collector is prepared by grinding a mixture of carbon particles, non-polar hydrocarbon oil, a surfactant and heavy oil under an oxidation or reduction atmosphere. The slime flotation collector preparation process provided by the application can realize high-value utilization of the carbon particles, and the prepared slime flotation collector can improve the slime flotation performance and improve the slime flotation separation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of coal slime flotation reagent research and development technology, specifically relating to a coal slime flotation collector, its preparation method and application. Background Technology

[0002] Flotation reagents for coal slime are an essential class of reagents in the coal slime flotation separation process. With the development and utilization of low-quality coal, various flotation collectors have been developed and applied. These include polar and non-polar component compound collectors, solid nanoparticle collectors, and solid-liquid mixed collectors. The polar component in compound collectors is often one or more of anionic, cationic, and nonionic surfactants, while the non-polar component is often one or more of chain alkanes and alkenes. Solid nanoparticle collectors include polystyrene nanoparticles, nano-silica, and nano-carbon particles. Solid-liquid mixed collectors combine the synergistic modification effects of micro / nano-scale solid particles and liquid reagent molecules on the physical morphology and chemical properties of the coal surface. While increasing the surface roughness of the coal, they also enhance its hydrophobicity, thereby strengthening the flotation recovery of coal slime.

[0003] Mechanical grinding in chemical preparation promotes chemical transformation through mechanical force (grinding, crushing, etc.) without requiring the overall dissolution of reactants. The mechanochemical effects are mainly manifested in: 1. changes in particle size, specific surface area, and density; 2. changes in particle lattice distortion, amorphization, and lattice disorder; 3. the removal of water of crystallization from the particle structure, reduction of reaction activation energy, and breaking and rearrangement of chemical bonds. By utilizing mechanochemical effects to increase the variety of effective components in solid-liquid mixed collectors, enhance the hydrophobic modification effect of collectors on the coal surface, and improve the flotation separation effect of coal slime, not only can the high-value utilization of various carbonaceous solid waste resources be achieved, but the recovery and clean utilization of coal resources can also be improved.

[0004] Patent (CN110293005B) proposes a liquid-solid composite collector for coal slime flotation. It is formulated with 0.5-5% ultrafine coal-based particles and 90%-99.5% liquid collectors such as kerosene, diesel oil, and n-dodecane by mass percentage. This liquid-solid composite collector can improve the hydrophobicity of the coal surface during flotation, thus improving the flotation effect of coal slime. However, this liquid-solid composite collector has a relatively small composition, limiting its effectiveness in enhancing the flotation of low-quality coals with strong hydrophilicity.

[0005] Patent (CN108636615B) proposes a method for preparing a flotation collector for fine-particle coal. By adding candle ash, prepared from the incomplete combustion of a candle, to non-polar hydrocarbon oil, it is believed to aid in the rupture of the hydration film on the mineral surface and the dispersion of oil droplets during flotation, thereby significantly improving the flotation recovery effect of coal slime. However, the candle ash used in this invention is difficult to prepare and is only suitable for laboratory research, making industrial application difficult.

[0006] Patent (CN115106200A) discloses a method for preparing a compound collector for coal preparation. This collector comprises vegetable oil, alkane esters, aromatic esters, and long-chain acids. The collector contains both polar and non-polar groups. The polar groups adsorb onto oxygen-containing sites on the coal surface, while the non-polar groups adsorb onto hydrophobic sites, thereby effectively improving the flotation effect of coal slime. However, this compound collector only alters the chemical properties of the coal surface through the synergistic adsorption of the collector onto polar and non-polar sites, resulting in a single modification method and limited enhancement effect on coal slime flotation. Summary of the Invention

[0007] The purpose of this invention is to provide a coal slime flotation collector, its preparation method, and its application. Based on the synergistic adsorption of polar and non-polar components on the surface of heterogeneous coal and the physical regulation of coal surface morphology by micro-nano hydrophobic particles, and with the aid of mechanochemical effects, a method is proposed to prepare a carbon / oil mixed slurry as a coal slime flotation collector by mechanical grinding under an oxidizing or reducing atmosphere.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] One of the technical solutions of this invention is to provide a method for preparing a coal slime flotation collector, comprising the following steps:

[0010] The coal slime flotation collector is obtained by grinding a mixture of carbon particles, non-polar hydrocarbon oil, surfactant and heavy oil under an oxidizing or reducing atmosphere.

[0011] Preferably, the oxidizing or reducing atmosphere includes an air atmosphere, an oxygen atmosphere, an ammonia atmosphere, or a water vapor atmosphere.

[0012] The purpose of introducing an oxidizing or reducing atmosphere during the mechanical grinding process in this invention is to utilize the principles of mechanochemistry to provide some polar and non-polar molecules, promote oxidation or reduction reactions at the particle-oil interface during high-energy grinding, and induce surface modification of carbon particles and diversification of liquid components.

[0013] Preferably, by mass fraction, the mixture contains 0.2 to 10 parts carbon particles, 50 to 99 parts non-polar hydrocarbon oil, 0.2 to 30 parts surfactant, and 1 to 40 parts heavy oil.

[0014] Preferably, the carbon particles have a particle size of <0.5mm and a fixed carbon content of >90wt.%.

[0015] More preferably, the carbon particles include one or more of graphite, pitch residue, coal slime, coal chemical slag, and biochar.

[0016] Preferably, the nonpolar hydrocarbon oil includes one or more of C10-C22 hydrocarbon oils; the surfactant includes one or more of fatty acids, aromatic esters and amino acids; the heavy oil is a mixture of saturated hydrocarbons, unsaturated hydrocarbons and aromatic hydrocarbons, wherein substances with a carbon chain length greater than 17 account for more than 50%.

[0017] Preferably, the grinding is performed until the diameter of the carbon particles in the mixture does not exceed 100 micrometers.

[0018] The second technical solution of the present invention is to provide a coal slime flotation collector prepared according to the above-mentioned method for preparing coal slime flotation collectors.

[0019] The third technical solution of the present invention provides an application of the above-mentioned coal slime flotation collector in coal slime flotation.

[0020] In use, the coal slime flotation collector is used directly as a collector for coal slime flotation; or the coal slime flotation collector is diluted with non-polar hydrocarbon oil and then used as a collector for coal slime flotation.

[0021] Preferably, when diluted with non-polar hydrocarbon oil, the volume ratio of the coal slime flotation collector to the non-polar hydrocarbon oil is 1:0.01 to 99.

[0022] The beneficial technical effects of the present invention are as follows:

[0023] Under the impact of mechanical grinding energy and an oxidizing / reducing atmosphere, not only is the particle size of carbon significantly reduced, but some non-polar hydrocarbon oils, surfactants, or heavy oils also extract from the newly formed surface of the carbon particles, resulting in a mechanochemical reaction. Some organic components from the carbon surface enter the liquid. The smaller, hydrophobic carbon particles can then be adsorbed onto the coal surface through hydrophobic interactions during subsequent flotation, increasing the surface roughness of the coal, promoting adhesion between coal and air bubbles, and enhancing coal flotation recovery. The organic components extracted into the liquid, in conjunction with non-polar hydrocarbon oils, surfactants, and heavy oils, are adsorbed on the heterogeneous surface of the coal, improving the hydrophobicity of the coal surface and ultimately enhancing the flotation recovery of coal slime.

[0024] The coal slime flotation collector preparation process provided by this invention not only enables the high-value utilization of carbon particles, but also improves the coal slime flotation performance and increases the coal slime flotation separation efficiency. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating the preparation process of the coal slime flotation collector in Example 1.

[0026] Figure 2Images of the kerosene used in Example 1, the prepared coal slime flotation collector, and the liquid obtained after centrifugation of the coal slime flotation collector, wherein a) is an image of kerosene, b) is an image of the coal slime flotation collector, and c) is an image of the coal slime flotation collector after centrifugation.

[0027] Figure 3 This is a particle size distribution diagram of the particles in the coal slime flotation collector prepared in Example 1. Detailed Implementation

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0029] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0031] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0032] Example 1

[0033] Preparation of coal slime flotation collector (see preparation flow chart) Figure 1 ):

[0034] Prepare 5 parts by weight of carbon particles (non-sticky coal particles with a particle size <0.5mm and a fixed carbon content >90wt.%), 90 parts of non-polar hydrocarbon oil (kerosene), 3 parts of surfactant (Triton X100), and 2 parts of commercially available heavy oil with a carbon chain length greater than 17 accounting for more than 50%; after mixing, mechanically grind in air for 1 hour to make the carbon particle diameter not exceed 100 micrometers, and use it directly as a collector for coal slime flotation.

[0035] Figure 2Images of the kerosene used in Example 1, the prepared coal slime flotation collector, and the liquid obtained after centrifugation of the coal slime flotation collector, wherein a) is an image of kerosene, b) is an image of the coal slime flotation collector, and c) is an image of the coal slime flotation collector after centrifugation.

[0036] from Figure 2 As can be seen, kerosene is a colorless liquid, while the coal slime flotation collector prepared in this invention is a black suspension. The liquid separated by centrifugation is a light green liquid. Fourier transform infrared spectroscopy analysis shows that it contains some alcohols and aromatic hydrocarbons.

[0037] Figure 3 This is a particle size distribution diagram of the particles in the coal slime flotation collector prepared in Example 1.

[0038] like Figure 3 As shown, the particle size distribution of the coal slime flotation collector prepared by this invention is between 100-3000 nm.

[0039] Coal slime flotation process flow:

[0040] (1) Add weakly caking coal with a particle size of less than 0.5 mm into the flotation cell, add tap water to adjust the slurry, and stir for 1 min;

[0041] (2) Add the collector to the slurry in step (1), stir for 3 minutes, then add the foaming agent 200 g / t (compared to the amount of dry coal slime), and stir for 0.5 minutes.

[0042] (3) Introduce air bubbles into the slurry from step (2) for flotation. The flotation time is 3 minutes. Collect the particles that float to the surface and the particles that remain in the slurry, as the final clean coal and tailings products.

[0043] Compared with traditional non-polar hydrocarbon oil (kerosene) collectors, the coal slime flotation collector prepared in this embodiment increases the clean coal yield by 15.31%, 30.17%, 45.54%, and 66.38% respectively when the collector addition amount is 500, 1000, 1500, or 2000 g / t (compared to the amount of dry coal slime), while keeping the clean coal ash content basically unchanged.

[0044] Example 2

[0045] Preparation of coal slime flotation collector:

[0046] Prepare, by weight, 2 parts of carbon granules (1 / 3 coking coal with a particle size < 5 mm and a fixed carbon content > 90 wt.%), 95 parts of non-polar hydrocarbon oil (diesel), 2 parts of surfactant (sodium cocoyl glycinate), and 1 part of commercially available heavy oil with a carbon chain length greater than 17 accounting for more than 50%; mix and then heat in a steam atmosphere (relative water content 8 g / m³). 3 The carbon particles are mechanically ground for 0.5 hours to ensure that the diameter of the carbon particles does not exceed 100 micrometers, and then used directly as a flotation collector for coal slime.

[0047] Coal slime flotation process flow:

[0048] (1) Add lignite with a particle size of less than 0.5 mm into the flotation cell, add tap water to adjust the slurry, and stir for 1 min;

[0049] (2) Add the collector to the slurry in step (1), stir for 3 minutes, then add the foaming agent methyl isobutyl methanol at a dosage of 1000 g / t (compared to the dosage of dry coal slime), and stir for 0.5 minutes.

[0050] (3) Introduce air bubbles into the slurry from step (2) for flotation. The flotation time is 3 minutes. Collect the particles that float to the surface and the particles that remain in the slurry, as the final clean coal and tailings products.

[0051] Compared with traditional non-polar hydrocarbon oil (diesel) collectors, the coal slime flotation collector prepared in this embodiment increased the clean coal yield by 15.77%, 23.28%, 29.54%, and 38.27% respectively when the collector addition amount was 5000, 10000, 15000, or 20000 g / t (compared to the amount of dry coal slime); and reduced the clean coal ash content by 2.47%, 4.34%, 5.71%, and 5.64% respectively.

[0052] Example 3

[0053] Preparation of coal slime flotation collector:

[0054] Prepare 10 parts by weight of charcoal particles (particle size < 5 mm, fixed carbon content > 90 wt.%), 80 parts of non-polar hydrocarbon oil (kerosene), 5 parts of surfactant (sodium oleate), and 5 parts of commercially available heavy oil with a carbon chain length greater than 17 accounting for more than 50% of the total. After mixing, mechanically grind the mixture for 2 hours under an ammonia atmosphere to ensure that the diameter of the charcoal particles does not exceed 100 micrometers. Then dilute the mixture 5 times with diesel oil and use it as a collector for coal slime flotation.

[0055] Coal slime flotation process flow:

[0056] (1) Add coking coal with a particle size of less than 0.5 mm into the flotation cell, add tap water to adjust the slurry, and stir for 3 minutes;

[0057] (2) Add the collector to the slurry from step (1) and stir for 3 minutes;

[0058] (3) Introduce air bubbles into the slurry from step (2) for flotation. The flotation time is 3 minutes. Collect the particles that float to the surface and the particles that remain in the slurry, as the final clean coal and tailings products.

[0059] Compared with traditional non-polar hydrocarbon oil (kerosene) collectors, the coal slime flotation collector prepared in this embodiment increased the clean coal yield by 2.68%, 2.27%, and 3.42% when the collector addition amount was 200, 500, or 800 g / t (compared to the amount of dry coal slime); and reduced the clean coal ash content by 0.57%, 1.07%, and 1.09%, respectively.

[0060] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a coal slime flotation collector, characterized in that, Includes the following steps: The coal slime flotation collector is obtained by grinding a mixture of carbon particles, non-polar hydrocarbon oil, surfactant and heavy oil under an oxidizing or reducing atmosphere. The oxidizing or reducing atmosphere includes an air atmosphere, an oxygen atmosphere, an ammonia atmosphere, or a water vapor atmosphere. By mass percentage, the mixture contains 0.2 to 10 parts carbon particles, 50 to 99 parts non-polar hydrocarbon oil, 0.2 to 30 parts surfactant, and 1 to 40 parts heavy oil. The nonpolar hydrocarbon oil includes one or more of C10-C22 hydrocarbon oils; the surfactants include one or more of fatty acids, aromatic esters and amino acids; the heavy oil is a mixture of saturated hydrocarbons, unsaturated hydrocarbons and aromatic hydrocarbons, wherein substances with a carbon chain length greater than 17 account for more than 50%.

2. The method for preparing the coal slime flotation collector according to claim 1, characterized in that, The carbon particles have a particle size of <0.5mm and a fixed carbon content of >90wt.%.

3. The method for preparing the coal slime flotation collector according to claim 2, characterized in that, The types of carbon particles include one or more of graphite, pitch residue, coal slime, coal chemical slag, and biochar.

4. The method for preparing the coal slime flotation collector according to claim 1, characterized in that, The grinding process involves grinding until the diameter of the carbon particles in the mixture does not exceed 100 micrometers.

5. A coal slime flotation collector prepared by the method of preparing the coal slime flotation collector according to any one of claims 1 to 4.

6. The application of the coal slime flotation collector according to claim 5 in coal slime flotation.

7. The application according to claim 6, characterized in that, The coal slime flotation collector is used directly as a collector for coal slime flotation; or the coal slime flotation collector is diluted with non-polar hydrocarbon oil and then used as a collector for coal slime flotation.

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