A composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, and its preparation method and application

Abstract

The present invention relates to the field of mineral flotation technology, and specifically to a composite nanoparticle collector for low-rank coal flotation that has both pore sealing and collision enhancement, as well as a preparation method and application thereof. Compared with conventional low-rank coal flotation collectors, the composite nanoparticle collector in the present invention synergistically improves the flotation efficiency of low-rank coal by enhancing collision and pore sealing. The composite nanoparticle collector has a smaller particle size and a larger specific surface area, which significantly increases the probability of collision and adhesion between the collector and the particles, shortens the adhesion time, and is beneficial to improving the flotation effect of low-rank coal. At the same time, the solidifying agent is melted by heating in a water bath and then rapidly cooled and solidified into nano-solid particles with a smaller particle size. During the flotation process of low-rank coal, it can spontaneously enter the complex pores and crack structures on the surface of the low-rank coal to produce a pore sealing effect; thereby significantly reducing the specific surface area of ​​the low-rank coal particles, achieving efficient adhesion between the collector and the coal particles, and greatly reducing the amount of collector used.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral flotation, and in particular to a composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement functions, as well as a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Low-rank coal refers to lignite, long flame coal, non-caking coal, weakly caking coal and some gas coal with a low degree of metamorphism. Low-rank coal produces a large amount of coal slime during the mining and sorting process. Flotation is one of the most widely used and efficient coal preparation methods for sorting fine-grained coal slime.

[0004] However, when flotating low-rank coal slime, challenges such as low efficiency, large reagent dosage, and poor floatability are encountered. This is because: the surface of low-rank coal contains abundant oxygen-containing functional groups and a dense hydration layer. This structure hinders the diffusion and adhesion of traditional collectors. At the same time, the complex pore and crack structure on the surface of low-rank coal is conducive to the infiltration and absorption of water molecules, resulting in an increase in the capillary effect and hydration phenomenon, which in turn causes a decrease in flotation efficiency and a significant increase in reagent consumption. In addition, the collector in the slurry cannot be completely dispersed due to insufficient stirring conditions, which affects its uniform distribution in the slurry. Unevenly distributed collectors will affect the final flotation effect. Emulsifying the collector can improve the dispersion of the collector, increase the contact area with coal particles, and achieve better flotation recovery effects with less oil consumption. However, conventional emulsions currently have large particle sizes (micrometers and above), resulting in poor emulsion stability and prone to sedimentation and phase separation. Improving emulsion stability requires significantly increasing the concentration of surfactants or adding additional polymer stabilizers, which also increases production costs. Therefore, it is necessary to develop a nanoscale collector system suitable for the efficient flotation of low-rank coal to address current issues such as low flotation efficiency, large reagent dosage, and poor floatability. Summary of the Invention

[0005] In order to overcome the above problems, the present invention provides a composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, as well as its preparation method and application. The composite nanoparticle collector provided by the present invention effectively solves the problem of low collision adhesion efficiency caused by the excessively large dispersed particle size and poor stability of hydrocarbon oil collectors.

[0006] In a first aspect of the present invention, a composite nanoparticle collector for low-rank coal flotation having both pore sealing and collision enhancement properties is provided, comprising the following raw materials in the following weight percentages:

[0007] Collecting agent 2-10%, curing agent 2-10%, surfactant 5-10%, and the rest is water.

[0008] A second aspect of the present invention provides a method for preparing the composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, comprising the following steps:

[0009] The curing agent is placed in a container and heated to melt it; a collecting agent and a surfactant are added to the melted curing agent liquid and stirred for the first time; water is then added and stirred for the second time; after the stirring is completed, the mixed liquid is transferred to a glass bottle and sealed, the bottle is quickly rinsed with cold water, and then placed in a refrigerator for cooling. After cooling, it is taken out to obtain a composite nanoparticle collector.

[0010] The composite nanoparticle collector comprises nanoemulsion and nano solid particles.

[0011] The third aspect of the present invention provides the use of the composite nanoparticle collector for low-rank coal flotation having both pore sealing and collision enhancement in the flotation of low-rank coal.

[0012] A fourth aspect of the present invention provides a method for flotation of low-rank coal, comprising:

[0013] The concentration of the low-rank coal slurry is adjusted, and then the composite nanoparticle collector for low-rank coal flotation with both sealing and collision enhancement is added. After being evenly mixed with the slurry, a frother is added, and after stirring and mixing, aeration flotation is performed.

[0014] The beneficial effects of the present invention are:

[0015] (1) In the present invention, the curing agent is melted by heating, and then the collecting agent and the surfactant are added. The first stirring is performed while heating, and then water is added and the second stirring is performed while heating. After stirring and homogenizing, the hot mixed liquid is transferred to a glass bottle and sealed. The bottle is quickly rinsed with cold water and then placed in a refrigerator for cooling, thereby forming a composite nanoparticle collector in the form of a nanoemulsion and nano solid particles. Compared with conventional low-rank coal flotation collectors, the composite nanoparticle collector prepared by the present invention synergistically improves the flotation efficiency of low-rank coal by strengthening collision and sealing pores. Specifically, the composite nanoparticle collector prepared by the present invention has a smaller particle size and a larger specific surface area, which significantly increases the probability of collision and adhesion between the collector and the particles, shortens the adhesion time, and is conducive to improving the flotation effect of low-rank coal. At the same time, the curing agent is melted by heating in a water bath and then rapidly cooled and solidified into nano-solid particles with smaller particle size. During the flotation process of low-rank coal, it can spontaneously enter the complex pores and crack structures on the surface of the low-rank coal, producing a sealing effect; thereby significantly reducing the specific surface area of ​​the low-rank coal particles, achieving efficient adhesion between the collector and the coal particles, and greatly reducing the amount of collector used.

[0016] (2) The composite nanoparticle collector prepared by the present invention has a smaller particle size, which makes the emulsion have higher stability and long-term preservation ability, and can be stably preserved for more than 3 months. In actual production practice, even after high-speed stirring such as slurry mixing or large-scale water dilution, it can still maintain a small nano size, excellent stability and application performance, which provides convenience for mineral flotation, especially low-rank coal flotation production process.

[0017] (3) The composite nanoparticle collector designed in the present invention is suitable for different types of minerals, and its particle size, hydrophobicity, and collision adhesion efficiency can be individually adjusted according to the properties of different coal mines, showing excellent adaptability and flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0019] Figure 1 This is a cryo-etching scanning electron microscope image of the composite nanoparticle collector prepared in Example 1;

[0020] Figure 2 The macroscopic morphology and particle size distribution of the composite nanoparticle collector prepared in Example 1 are shown. DETAILED DESCRIPTION

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] A first typical embodiment of the present invention provides a composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, which is composed of the following raw materials in the following weight percentages:

[0024] Collecting agent 2-10%, curing agent 2-10%, surfactant 5-10%, and the rest is water.

[0025] In one or more embodiments, the collecting agent is one or more of diesel, kerosene, gasoline, and fatty acid esters.

[0026] Preferably, the fatty acid esters include methyl oleate, ethyl oleate, methyl octanoate, ethyl octanoate, and the like.

[0027] In one or more embodiments, the curing agent is one of beeswax, solid paraffin, and liquid paraffin.

[0028] In one or more embodiments, the surfactant is one or more of a nonionic surfactant and an anionic-nonionic surfactant;

[0029] Preferably, the nonionic surfactant includes fatty alcohol polyoxyethylene ether, preferably AEO-7, and the anionic-nonionic surfactant includes fatty alcohol polyoxyethylene ether carboxylate, fatty alcohol polyoxyethylene ether sulfonate, alkyl naphthol polyoxyethylene ether sulfonate, alkyl naphthol polyoxyethylene ether carboxylate, etc.

[0030] A second typical embodiment of the present invention provides a method for preparing the composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, comprising the following steps:

[0031] The curing agent is placed in a container and heated to melt it; a collecting agent and a surfactant are added to the melted curing agent liquid and stirred for the first time; water is then added and stirred for the second time; after the stirring is completed, the mixed liquid is transferred to a glass bottle and sealed, the bottle is quickly rinsed with cold water, and then placed in a refrigerator for cooling. After cooling, it is taken out to obtain a composite nanoparticle collector.

[0032] The composite nanoparticle collector comprises nanoemulsion and nano solid particles.

[0033] In one or more embodiments, the temperature for heating to melt the curing agent is 40-90°C, preferably 80°C.

[0034] In one or more embodiments, the first stirring speed is 400-600 r / min, and the stirring time is 5-10 min.

[0035] In one or more embodiments, the second stirring speed is 800-1200 r / min, and the stirring time is 10-20 min.

[0036] In one or more embodiments, to prevent the curing agent from solidifying during the stirring process, water bath heating is performed simultaneously during the first and second stirring processes. The water bath heating temperature is 40-90° C., preferably 80° C. Water bath heating can enhance the molecular activity of the curing agent and allow it to be fully miscible with the collecting agent; it can also enhance the emulsification effect of the surfactant molecules, thereby improving the emulsification effect.

[0037] In one or more embodiments, the cooling time in the refrigerator is 10 to 20 minutes. After the heating process is completed, the reaction system is rapidly cooled to form a composite nanoparticle collector in the form of a nanoemulsion and nano solid particles.

[0038] In one or more embodiments, the particle size of the composite nanoparticle collector used in the low-rank coal flotation with both pore sealing and collision enhancement is 10 to 70 nm.

[0039] A third typical embodiment of the present invention provides the use of the composite nanoparticle collector for low-rank coal flotation having both pore sealing and collision enhancement in low-rank coal flotation.

[0040] A fourth typical embodiment of the present invention provides a method for flotation of low-rank coal, comprising:

[0041] The concentration of the low-rank coal slurry is adjusted, and then the composite nanoparticle collector for low-rank coal flotation with both sealing and collision enhancement is added. After being evenly mixed with the slurry, a frother is added, and after stirring and mixing, aeration flotation is performed.

[0042] In one or more embodiments, the concentration of the low-rank coal slurry is 80-90 g / L, preferably 80 g / L.

[0043] In one or more embodiments, the amount of composite nanoparticle collector used for low-rank coal flotation with both pore sealing and collision enhancement is 17.50-18.50 kg, preferably 18 kg, per ton of low-rank coal slime. It should be noted that the composite nanoparticle collector contains a significant amount of water (over 70%), and the actual amount of collector used should be less than 10%.

[0044] In one or more embodiments, the foaming agent is octanol, and the amount is 500 g per ton of dry coal to be floated; after the foaming agent is added, the slurry is mixed for 30 seconds, and aeration flotation is performed.

[0045] In one or more embodiments, the inflation volume is 0.1m 3 / h, the stirring speed is 1800r / min, and the flotation time is about 3min.

[0046] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0047] Example 1

[0048] A composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, comprising the following raw materials in the following weight percentages:

[0049] The composition includes 5% collector agent, 3.5% curing agent, 8.5% surfactant, and 83% water. The collector agent is diesel, the curing agent is beeswax, and the surfactant is AEO-7.

[0050] Specific preparation method:

[0051] (1) Weigh each component by mass: 5 parts diesel, 3.5 parts beeswax, 8.5 parts AEO-7, and 83 parts water.

[0052] (2) The weighed beeswax was placed in a beaker and heated in a water bath (70°C) until melted. Diesel and AEO-7 were added to the melted beeswax in sequence and mixed evenly using a magnetic stirrer (speed of 600 r / min, stirring time of 5 min). While stirring, the mixture was heated in a water bath (temperature of 70°C).

[0053] (3) adding water to the mixed oil phase prepared in step (2), and dispersing the mixed oil phase in water using a magnetic stirrer (rotation speed of 1000 r / min, stirring time of 15 minutes), while heating in a water bath (temperature of 70° C.) while stirring. After stirring, the mixed solution is transferred to a glass bottle, sealed, and quickly rinsed with cold water. The bottle is then placed in a refrigerator and cooled for 15 minutes to prepare a uniform and stable composite nanoparticle collector comprising a nanoemulsion and nano solid particles.

[0054] Figure 1 This is a cryo-etching scanning electron microscope image of the composite nanoparticle collector prepared in this example;

[0055] Figure 2 The particle size diagram of the composite nanoparticle collector prepared in this embodiment is shown in FIG. Figure 2 It can be seen from the figure that the particle size of the composite nanoparticle collector prepared in this embodiment is 10-70 nm, and the average particle size is 36.74 nm.

[0056] Example 2

[0057] A composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, comprising the following raw materials in the following weight percentages:

[0058] The composition includes 3.5% collector agent, 5% curing agent, 8.5% surfactant, and 83% water. The collector agent is diesel, the curing agent is beeswax, and the surfactant is AEO-7.

[0059] Specific preparation method:

[0060] (1) Weigh each component by mass: 3.5 parts diesel, 5 parts beeswax, 8.5 parts AEO-7, and 83 parts water.

[0061] (2) The weighed beeswax was placed in a beaker and heated in a water bath (80°C) until melted. Diesel and AEO-7 were added to the melted beeswax in sequence and mixed evenly using a magnetic stirrer (speed of 600 r / min, stirring time of 5 min). While stirring, the mixture was heated in a water bath (temperature of 80°C).

[0062] (3) adding water to the mixed oil phase prepared in step (2), and dispersing the mixed oil phase in water using a magnetic stirrer (rotation speed of 1000 r / min, stirring time of 15 minutes), while heating in a water bath (temperature of 80° C.) while stirring. After stirring, the mixed solution is transferred to a glass bottle, sealed, and quickly rinsed with cold water. The bottle is then placed in a refrigerator and cooled for 15 minutes to prepare a uniform and stable composite nanoparticle collector comprising a nanoemulsion and nano solid particles.

[0063] Example 3

[0064] A composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, comprising the following raw materials in the following weight percentages:

[0065] The composition includes 2% collector agent, 6.5% curing agent, 8.5% surfactant, and 83% water. The collector agent is diesel, the curing agent is beeswax, and the surfactant is AEO-7.

[0066] Specific preparation method:

[0067] (1) Weigh each component by mass: 2 parts diesel, 6.5 parts beeswax, 8.5 parts AEO-7, and 83 parts water.

[0068] (2) The weighed beeswax was placed in a beaker and heated in a water bath (85°C) until melted. Diesel and AEO-7 were added to the melted beeswax in sequence and mixed evenly using a magnetic stirrer (speed of 600 r / min, stirring time of 5 min). While stirring, the mixture was heated in a water bath (temperature of 85°C).

[0069] (3) adding water to the mixed oil phase prepared in step (2), and dispersing the mixed oil phase in water using a magnetic stirrer (rotation speed of 1000 r / min, stirring time of 15 minutes), while heating in a water bath (temperature of 85° C.) while stirring. After stirring, the mixed solution is transferred to a glass bottle, sealed, and quickly rinsed with cold water. The bottle is then placed in a refrigerator and cooled for 15 minutes to prepare a uniform and stable composite nanoparticle collector comprising a nanoemulsion and nano solid particles.

[0070] Example 4

[0071] A composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, comprising the following raw materials in the following weight percentages:

[0072] The composition includes 5% collector agent, 3.5% curing agent, 8.5% surfactant, and 83% water. The collector agent is diesel, the curing agent is solid paraffin, and the surfactant is AEO-7.

[0073] Specific preparation method:

[0074] (1) Weigh each component by mass: 5 parts diesel, 3.5 parts paraffin wax, 8.5 parts AEO-7, and 83 parts water.

[0075] (2) The weighed solid paraffin was placed in a beaker and heated in a water bath (60°C) until melted. Diesel and AEO-7 were added to the melted solid paraffin in sequence and mixed evenly using a magnetic stirrer (speed of 600 r / min, stirring time of 5 min). While stirring, the mixture was heated in a water bath (temperature of 60°C).

[0076] (3) adding water to the mixed oil phase prepared in step (2), and dispersing the mixed oil phase in water using a magnetic stirrer (rotation speed of 1000 r / min, stirring time of 15 minutes), while heating in a water bath (temperature of 60° C.) while stirring. After stirring, the mixed solution is transferred to a glass bottle, sealed, and quickly rinsed with cold water. The bottle is then placed in a refrigerator and cooled for 15 minutes to prepare a uniform and stable composite nanoparticle collector comprising a nanoemulsion and nano solid particles.

[0077] Example 5

[0078] A composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, comprising the following raw materials in the following weight percentages:

[0079] The composition comprises 3.5% collecting agent, 5% curing agent, 8.5% surfactant and 83% water, wherein the collecting agent is diesel, the curing agent is beeswax and the surfactant is sodium lauryl polyoxyethylene ether carboxylate.

[0080] Specific preparation method:

[0081] (1) Weigh each component by mass: weigh 3.5 parts of diesel, 5 parts of beeswax, 8.5 parts of sodium lauryl polyoxyethylene ether carboxylate, and 83 parts of water.

[0082] (2) The weighed beeswax was placed in a beaker and heated in a water bath (80°C) until melted. Diesel oil and sodium lauryl polyoxyethylene ether carboxylate were added to the melted beeswax in sequence, and the three were mixed evenly using a magnetic stirrer (speed of 600 r / min, stirring time of 5 min), and heated in a water bath (temperature of 80°C) while stirring.

[0083] (3) adding water to the mixed oil phase prepared in step (2), and dispersing the mixed oil phase in water using a magnetic stirrer (rotation speed of 1000 r / min, stirring time of 15 minutes), while heating in a water bath (temperature of 80° C.) while stirring. After stirring, the mixed solution is transferred to a glass bottle, sealed, and quickly rinsed with cold water. The bottle is then placed in a refrigerator and cooled for 15 minutes to prepare a uniform and stable composite nanoparticle collector comprising a nanoemulsion and nano solid particles.

[0084] Example 6

[0085] A composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, comprising the following raw materials in the following weight percentages:

[0086] The composition comprises 3.5% collecting agent, 5% curing agent, 8.5% surfactant and 83% water, wherein the collecting agent is diesel, the curing agent is beeswax and the surfactant is sodium dodecylnaphthol polyoxyethylene ether carboxylate.

[0087] Specific preparation method:

[0088] (1) Weigh each component by mass: weigh 3.5 parts of diesel, 5 parts of beeswax, 8.5 parts of sodium lauryl naphthol polyoxyethylene ether carboxylate, and 83 parts of water.

[0089] (2) The weighed beeswax was placed in a beaker and heated in a water bath (80°C) until melted. Diesel oil and sodium dodecylnaphthol polyoxyethylene ether carboxylate were added to the melted beeswax in sequence. The three were mixed evenly using a magnetic stirrer (speed of 600 r / min, stirring time of 5 min), and heated in a water bath (temperature of 80°C) while stirring.

[0090] (3) adding water to the mixed oil phase prepared in step (2), and dispersing the mixed oil phase in water using a magnetic stirrer (rotation speed of 1000 r / min, stirring time of 15 minutes), while heating in a water bath (temperature of 80° C.) while stirring. After stirring, the mixed solution is transferred to a glass bottle, sealed, and quickly rinsed with cold water. The bottle is then placed in a refrigerator and cooled for 15 minutes to prepare a uniform and stable composite nanoparticle collector comprising a nanoemulsion and nano solid particles.

[0091] Example 7

[0092] A composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, comprising the following raw materials in the following weight percentages:

[0093] The composition includes 3.5% collecting agent, 5% curing agent, 8.5% surfactant, and 83% water. The collecting agent is diesel, the curing agent is liquid paraffin, and the surfactant is AEO-7.

[0094] Specific preparation method:

[0095] (1) Weigh each component by mass: 3.5 parts diesel, 5 parts liquid paraffin, 8.5 parts AEO-7, and 83 parts water.

[0096] (2) Liquid paraffin was placed in a beaker and heated in a water bath (50°C) until melted. Diesel and AEO-7 were added to the melted liquid paraffin in sequence and mixed evenly using a magnetic stirrer (speed of 600 r / min, stirring time of 5 min). While stirring, the mixture was heated in a water bath (temperature of 50°C).

[0097] (3) adding water to the mixed oil phase prepared in step (2), and dispersing the mixed oil phase in water using a magnetic stirrer (rotation speed of 1000 r / min, stirring time of 15 minutes), while heating in a water bath (temperature of 50° C.) while stirring. After stirring, the mixed solution is transferred to a glass bottle, sealed, and quickly rinsed with cold water. The bottle is then placed in a refrigerator and cooled for 15 minutes to prepare a uniform and stable composite nanoparticle collector comprising a nanoemulsion and nano solid particles.

[0098] Experimental Example 1

[0099] (1) Flotation test

[0100] The flotation of low-rank coal using the composite nanoparticle collector prepared by the present invention comprises the following steps:

[0101] The concentration of the coal ore pulp to be floated is adjusted to 80g / L, different collectors are added, stirred and mixed, and then waited for 2 minutes, and then the frother is added, stirred and mixed, and then waited for 30 seconds, and then aerated flotation is performed. The aeration volume is 0.1m 3 / h, the stirring speed was 1800r / min, and the flotation time was approximately 3 minutes. The amount of the composite nanoparticle collector prepared in Examples 1 to 4 was 18kg per ton of low-rank coal slime. It should be noted that the composite nanoparticle collector contains approximately 83% water by mass, and the actual amount of collecting agents used accounts for 2% to 5% of the composite nanoparticle collector. In the experiment, control sample 1 used conventional flotation agent diesel at a dosage of 3000g / t, and the frother was fixed to octanol at a dosage of 500g / t.

[0102] It should be noted that the coal sample used in the test was subbituminous coal with an ash content of 17.48%. After crushing, screening, blending, and fractionation, the raw coal was prepared to a particle size of less than 0.5 mm according to the "Method for Preparation of Coal Samples" (GB474-1984). Performance testing was conducted in accordance with the "Coal Preparation Laboratory Unit Flotation Test Method" (GB4758-1984). The final test results are shown in Table 1.

[0103] Table 1 Flotation performance test results of low-rank coal

[0104] Test items Clean coal yield / % Clean coal ash content / % Flotation perfection index / % Combustible material recovery rate / % Example 1 81.26 12.82 26.25 85.88 Example 2 87.47 12.28 31.53 92.98 Example 3 82.98 12.58 28.19 87.89 Example 4 83.52 12.47 29.01 88.59 Control sample 1 64.72 13.29 18.80 68.01

[0105] As can be seen from Table 1, compared with the test results of control sample 1, the ash content of the clean coal obtained after using the composite nanoparticle collector prepared in Examples 1 to 4 of the present invention decreased by 0.5 to 1%. At the same time, the clean coal productivity and flotation efficiency were also improved, further verifying the advantage of the composite nanoparticle collector in low-rank coal selectivity, thereby effectively improving the flotation performance of low-rank coal.

[0106] (2) BET surface area tests were conducted on coal samples before and after treatment with different collectors. The experimental steps included: preparing the coal slurry to a concentration of 80 g / L, adding different collectors, and stirring the mixture evenly with a magnetic stirrer at a speed of 600 r / min for 5 min. After stirring, the filter cake obtained by filtration was placed in a 30°C oven for vacuum drying. The dried samples were then tested using a BET surface area and pore size analyzer (V-Sord 2800TP, Beijing Guoyi Precision Measurement Technology Co., Ltd.). Specific test results are shown in Table 2.

[0107] Table 2 Test results of low-rank coal surface pore structure before and after the action of different collectors

[0108]

[0109]

[0110] As can be seen from Table 2, compared with the test results of control sample 1, the specific surface area, total adsorption pore volume and average pore diameter of the low-rank coal samples treated with the composite nanoparticle collectors prepared in Examples 1 to 4 of the present invention are greatly reduced, indicating that the composite nanoparticle collectors can spontaneously enter the complex pore structure on the surface of the low-rank coal, produce the effect of sealing the pores and significantly reducing the drug consumption.

[0111] (3) Stability testing

[0112] The composite nanoparticle collector prepared in Example 1 has a particle size of 10 to 70 nm, with an average particle size of 36.74 nm. After being placed at room temperature for 3 months, the particle size of the composite nanoparticle collector is still between 10 and 70 nm, with an average particle size of 40.23 nm, indicating that the composite nanoparticle collector prepared by the present invention has excellent stability and long-term storage capacity, and can be stably stored for more than 3 months. In actual production practice, even after high-speed stirring such as slurry mixing or dilution with a large amount of water (10 times the volume of water), the particle size of the composite nanoparticle collector can still be maintained below 100 nm. It has a small nanometer size, excellent stability and application performance, and provides convenience for mineral flotation, especially low-rank coal flotation production process.

[0113] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A composite nanoparticle collector for low-rank coal flotation with both pore sealing and collision enhancement, characterized in that: It is composed of the following raw materials in percentage by weight: Collecting agent 2~10%, curing agent 2~10%, surfactant 5~10%, and the rest is water; The collecting agent is one or more of diesel, kerosene, gasoline, and fatty acid esters; The curing agent is one of beeswax, solid paraffin and liquid paraffin; The surfactant is one or more of a nonionic surfactant and an anionic-nonionic surfactant; The composite nanoparticle collector comprises a nanoemulsion and nano solid particles; the particle size of the composite nanoparticle collector is 10-70 nm.

2. The method for preparing the composite nanoparticle collector according to claim 1, characterized in that: The following steps are involved: The curing agent is placed in a container and heated to melt it; a collecting agent and a surfactant are added to the melted curing agent liquid and stirred for the first time; water is then added and stirred for the second time; after the stirring is completed, the mixed liquid is transferred to a glass bottle and sealed, the bottle is quickly rinsed with cold water, and then placed in a refrigerator for cooling. After cooling, it is taken out to obtain a composite nanoparticle collector.

3. The preparation method according to claim 2, wherein The temperature for heating to melt the curing agent is 40~90℃.

4. The preparation method according to claim 3, wherein The temperature at which the curing agent is heated to melt is 80°C.

5. The preparation method according to claim 2, wherein The first stirring speed is 400-600 r / min, and the stirring time is 5-10 min; Alternatively, the second stirring speed is 800~1200 r / min, and the stirring time is 10~20 min.

6. The preparation method according to claim 2, wherein During the first and second stirring processes, water bath heating is performed simultaneously at a temperature of 40-90°C. Alternatively, cool in the refrigerator for 10 to 20 minutes.

7. The preparation method according to claim 6, wherein During the first stirring and the second stirring, water bath heating was performed simultaneously, and the water bath heating temperature was 80°C.

8. Use of the composite nanoparticle collector according to claim 1 and / or the composite nanoparticle collector prepared by the preparation method according to any one of claims 2 to 7 in the flotation of low-rank coal.

9. A method for flotation of low-rank coal, characterized in that: include: The concentration of the low-rank coal slurry is adjusted, and then the composite nanoparticle collector according to claim 1 and / or the composite nanoparticle collector prepared by the preparation method according to any one of claims 2 to 7 is added. After being evenly mixed with the slurry, a foaming agent is added, and after stirring and mixing, aeration flotation is performed.

10. The method according to claim 9, wherein The addition amount of composite nanoparticle collector for low-rank coal flotation with both sealing and collision enhancement is 17.50~18.50 kg per ton of low-rank coal slime.

11. The method according to claim 10, wherein The addition amount of composite nanoparticle collector for low-rank coal flotation with both sealing and collision enhancement is 18 kg per ton of low-rank coal slime.

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