Low-rank coal composite flotation reagent as well as preparation method and application thereof

Abstract

The invention discloses a low-rank coal composite flotation reagent and a preparation method and application thereof, and belongs to the technical field of coal flotation of mineral processing. The agent specifically comprises a composite collecting agent and a composite foaming agent, and the composite collecting agent comprises kerosene, n-dodecane, oleic acid, dimer acid, sodium stearate, terpilenol, diethyl phthalate, alkylphenol ethoxylates, span-80, trioctyl phosphate and 2-ethylhexanol. The composite foaming agent is prepared from the following components: terpilenol, terpenic oil, sec-octyl alcohol and sodium alpha-olefin sulfonate. Compared with a traditional single flotation reagent combination, the composite flotation reagent has a remarkable effect in fine coal flotation, and particularly when coal with the particle size smaller than 0.5 mm is treated, the flotation efficiency, the clean coal yield and the combustible body recovery rate can be effectively improved. More importantly, the medicament is stable at normal temperature, the layering phenomenon is avoided, the long-term effectiveness is ensured, and the medicament has extremely high industrial application potential.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal flotation in mineral processing, and specifically relates to a composite flotation reagent for low-rank coal, a preparation method thereof, and an application thereof. Background Art

[0002] As an important low-rank coal, the efficient development and utilization of long-flame coal is of far-reaching significance to national energy security and environmental protection. In coal separation technology, the flotation process has become an important means for separating low-rank coal due to its high efficiency and economy. However, traditional flotation reagents have problems such as poor adaptability, low flotation efficiency, and environmental pollution during the flotation process of long-flame coal. In recent years, composite flotation reagents have become a research hotspot due to their synergistic effects and multifunctionality. For example, Yang Chongyi et al. studied the influence of the compounding schemes of different surfactants on the coal flotation effect, and the results showed that the application of composite reagents could significantly increase the output ratio of clean coal. In the article "Synergistic effects of dodecane-castor oil acid mixture on the flotation responses of low-rank coal: A combined simulation and experimental study" by Xu et al., the influence of composite collectors on the flotation of low-rank coal was studied by combining theory and experiment, and it was found that the composite reagent could enhance the hydrophobicity of coal and enhance the diffusion and interaction of surfactant molecules at the interface between low-rank coal particles and water.

[0003] However, the research on composite flotation reagents for long-flame coal is still insufficient, and there is no systematic mechanism explanation yet. In view of this, the present invention is committed to exploring the specific influence of composite flotation reagents on the flotation performance of long-flame coal, aiming to lay a solid theoretical foundation for improving the flotation efficiency of long-flame coal and providing practical technical support.

[0004] Due to the characteristics of long-flame coal such as high volatile matter, high moisture content, and large variation in ash content, the selection of collectors and frothers is crucial during its flotation process. Traditional collectors such as diesel oil and kerosene can play a role to a certain extent, but due to the special surface properties of long-flame coal, the adaptability of these conventional collectors to long-flame coal is insufficient, resulting in a large amount of reagent waste and unsatisfactory flotation effects. Currently, commonly used frothers such as sec-octanol, when used for the flotation of long-flame coal, the foam stability and flotation selectivity generated are difficult to reach an ideal state. At the same time, the existing reagent preparation methods have problems such as complex processes and high costs, which limit their wide application in the long-flame coal flotation industry.

[0005] Currently, the mainstream preparation methods of composite collectors and frothers are as follows:

[0006] Preparation method of composite collector:

[0007] (1) Surfactant compounding: Select different types of surfactants, such as anionic surfactants (such as fatty acid salts, sulfonates, etc.) and non-ionic surfactants (such as polyoxyethylene ethers) for compounding. According to the principle of surfactant synergistic effect, the interaction between different surfactant molecules can change the adsorption form and adsorption amount on the coal surface, enhancing the collection performance for low-rank coal, etc.

[0008] (2) Adding functional additives: Add functional substances on the basis of traditional collectors, such as organic compounds containing elements such as nitrogen, phosphorus, and sulfur. These additives can undergo chemical reactions or form strong physical adsorption with specific active sites on the coal surface, enhancing the affinity between the collector and the coal surface. For example, adding nitrogen-containing amine compounds to hydrocarbon collectors such as diesel, and the amino group can undergo hydrogen bonding or acid-base neutralization with oxygen-containing functional groups on the surface of low-rank coal.

[0009] (3) Polymer modification: Modify traditional collectors using polymer compounds. Through chemical reactions such as grafting and copolymerization, introduce polymer chain segments with specific functions into the collector molecules. For example, graft copolymerize monomers such as acrylic acid with traditional collector molecules, so that the modified collector molecules have better dispersibility and adsorption selectivity. At the same time, the steric hindrance effect of the polymer chain can enhance the stability of the hydrophobic layer on the coal particle surface.

[0010] (4) Nanomaterial compounding: Compound nanomaterials with collectors. Nanomaterials have a high specific surface area and unique surface properties, which can improve the adsorption efficiency and uniformity of collectors on the coal surface. For example, mixing nanometer titanium dioxide with collectors, and the nanometer titanium dioxide can be adsorbed on the coal surface, changing the electron cloud distribution on the coal surface, enhancing the adsorption ability of collector molecules, and thus improving the collection effect.

[0011] Preparation method of composite frother:

[0012] (1) Compound different-structured frothers: Select frothers with different chemical structures, such as alcohol frothers (such as amyl alcohol, octyl alcohol), ether frothers (such as polyethylene glycol ether), and ester frothers (such as ethyl acetate) for compounding. According to the "synergistic frothing effect", the adsorption and arrangement modes of different frothers at the gas-liquid interface are different. After compounding, the properties of bubbles can be optimized, such as generating bubbles with appropriate size and good stability. By adjusting the compounding ratio, the requirements of different coal qualities and flotation conditions can be met.

[0013] (2) Introduction of special functional groups: Chemically modify the frother molecules to introduce special functional groups. For example, introducing fluorine-containing functional groups into the frother molecules. Fluorine-containing groups have extremely low surface energy, which can significantly reduce the surface tension at the gas-liquid interface, making it easier to generate bubbles and improving their stability. At the same time, the presence of fluorine-containing functional groups can also improve the selectivity of the frother and reduce the flotation of gangue minerals.

[0014] (3) Polymer-modified frothers: Modify the frothers using polymers. Connect the frother molecules with polymer chains through polymerization reactions to form polymer-type frothers with special properties. For example, polymerizing acrylic acid with alcohol-based frothers, the resulting polymer-type frother has good water solubility and foaming properties, and its molecular chains can form a network structure on the surface of the bubbles, enhancing the stability and anti-deformation ability of the bubbles.

[0015] (4) Addition of auxiliary components: Add some auxiliary components to the frother, such as electrolytes, surface activity enhancers, etc. Electrolytes can affect the adsorption behavior of frother molecules at the gas-liquid interface by changing the ionic strength and surface potential of the solution; surface activity enhancers can act synergistically with frother molecules to further reduce the surface tension and improve the generation and stability of bubbles. For example, adding an appropriate amount of electrolytes such as sodium chloride can optimize the foaming performance of the frother, and adding a small amount of sodium dodecyl sulfate can enhance the surface activity of the frother.

[0016] Therefore, it is of great practical significance to develop a composite collector and frother with high efficiency, low cost and suitable for long-flame coal, as well as its preparation method. Summary of the Invention

[0017] Aiming at the deficiencies of the prior art, the present invention provides a composite flotation reagent for low-rank coal and its preparation method, aiming to solve the technical problems commonly existing in existing reagents, such as low flotation efficiency, large reagent consumption and complex operation processes, especially in the flotation operation of long-flame coal, problems such as poor matching between the collector and the frother, low output efficiency of clean coal, and relatively high ash content of clean coal.

[0018] A composite flotation reagent for low-rank coal, specifically a composite collector and a composite frother. The components of the composite collector, calculated by mass fraction, include 45% - 55% kerosene, 10% - 15% n-dodecane, 7% - 14% oleic acid, 2% - 6% dimer acid, 1% - 5% sodium stearate, 3% - 10% terpineol, 10% - 18% diethyl phthalate, 0.5% - 3% alkylphenol polyoxyethylene ether, 1.5% - 6% Span-80, 1% - 4% tributyl phosphate, 1% - 3% 2-ethylhexanol;

[0019] The components of the composite foaming agent, by mass fraction, include 40% - 60% terpineol, 40% - 60% pine oil alcohol, 10% - 15% sec-octyl alcohol, and 3% - 6% α-olefin sulfonate sodium.

[0020] The preparation method of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0021] (1) Solution preparation: According to the components of the composite collector and the composite foaming agent, they are proportioned respectively, and after mixing evenly, the collector solution and the foaming agent solution are obtained;

[0022] (2) Ultrasonic emulsification: The obtained collector solution and foaming agent solution are respectively placed under ultrasonic conditions for emulsification to obtain a collector mixture and a foaming agent mixture for standby;

[0023] (3) Deep emulsification: The collector mixture and the foaming agent mixture are respectively placed in a hydrothermal reaction kettle for heating, and then stirred for deep emulsification to obtain the composite collector and the composite foaming agent.

[0024] Among them:

[0025] In the step (2), the ultrasonic frequency is 15 kHz - 25 kHz, and the ultrasonic emulsification time is 0.5 h - 1 h.

[0026] In the step (3), the collector mixture and the foaming agent mixture are heated to 50 °C - 85 °C.

[0027] In the step (3), the stirring time during the deep emulsification process is 25 min - 60 min.

[0028] The application of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0029] S1. The low-rank coal blocks are crushed and ground to a particle size ≤ 0.5 mm, and the obtained coal powder is mixed with water for pulp preparation to obtain a coal pulp for standby;

[0030] S2. The coal pulp is placed in a flotation machine for pre-stirring, then the composite collector is added and stirred continuously, and then the composite foaming agent is added. After stirring, the air inlet valve is opened to inflate and scrape the foam until there is no obvious froth concentrate coal, and the flotation concentrate coal and tail coal are obtained;

[0031] S3. The obtained flotation concentrate coal and tail coal are respectively dried and weighed, and the concentrate coal yield, ash content, and combustible matter recovery rate are calculated.

[0032] Among them:

[0033] In the step S1, the concentration of the coal pulp is 100 g / L - 200 g / L, and the rotation speed of the flotation machine is 1800 r / min - 2000 r / min.

[0034] In the step S2, the pre-stirring time is 2 min to 4 min, the addition amount of the composite collector is 30 μL / L to 100 μL / L, and the stirring time is 2 min to 4 min.

[0035] In the step S2, the addition amount of the composite foaming agent is 10 μL / L to 40 μL / L, and after adding, stir for 2 min to 4 min.

[0036] In the step S3, the yield of the flotation clean coal is 35% to 55%, the ash content is 10% to 15%, and the combustible recovery rate is 70% to 77%.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] 1. Innovative collector and foaming agent design: The present invention innovatively uses a non-polar base oil with excellent hydrophobicity as the collector, and introduces a high-surface-activity substance, terpineol, as the foaming agent. Under the synergistic effect of the activator and the emulsifier, through the normal-temperature emulsification technology, a novel composite flotation reagent is successfully prepared. The preparation process is simple and efficient, without complex operation procedures, with low cost, and has great potential for industrial promotion.

[0039] 2. Significantly improved flotation efficiency: Compared with the traditional single flotation reagent combination (such as kerosene + sec-octanol), the composite flotation reagent prepared by the present invention shows a significant improvement in flotation efficiency during the flotation of fine coal with a particle size < 0.5 mm.

[0040] 3. Optimized reagent stability and wide raw material sources: Compared with the composite reagents on the existing market, the composite flotation reagent of the present invention not only has a simple preparation process, but also has a wide variety of raw material sources. More importantly, the present invention overcomes the problem of insufficient reagent stability, can remain stable at room temperature, avoid stratification, and shows good reagent selectivity and collection performance.

[0041] 4. Convenient and efficient application: The composite flotation reagent prepared by the present invention is extremely convenient to use, and can be directly added and used without additional dispersion and emulsification equipment. The dosage of the reagent is relatively small, but the flotation effect is more significant, showing high flexibility and practicability. Specific embodiments

[0042] Example 1

[0043] A low-rank coal composite flotation reagent, specifically a composite collector and a composite frother. The components of the composite collector, by mass fraction, include 45% kerosene, 10% n-dodecane, 8% oleic acid, 4% dimer acid, 3% sodium stearate, 7% terpineol, 14% diethyl phthalate, 0.5% alkylphenol polyoxyethylene ether, 3.5% Span-80, 3% tributyl phosphate, and 2% 2-ethylhexanol;

[0044] The components of the composite frother, by mass fraction, include 40% terpineol, 40% pine oil, 15% sec-octanol, and 5% α-olefin sulfonate.

[0045] The preparation method of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0046] (1) Solution preparation: According to the components of the composite collector and the composite frother, they are proportioned respectively, and after mixing evenly, a collector solution and a frother solution are obtained;

[0047] (2) Ultrasonic emulsification: The obtained collector solution and frother solution are respectively placed under ultrasonic conditions for emulsification. The ultrasonic frequency is 15 kHz, and the ultrasonic emulsification time is 1 h to obtain a collector mixture and a frother mixture for standby;

[0048] (3) Deep emulsification: The collector mixture and the frother mixture are respectively placed in a hydrothermal reaction kettle and heated to 65 °C, and then stirred for 30 min for deep emulsification to obtain a composite collector and a composite frother.

[0049] The application of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0050] S1. The low-rank coal blocks are crushed and ground to a particle size ≤ 0.5 mm, and the obtained coal powder is mixed with water for pulp preparation to obtain a coal slurry with a concentration of 108 g / L for standby;

[0051] S2. The coal slurry is placed in a flotation machine with a rotation speed of 1900 r / min for pre-stirring for 3 min, and then a composite collector is added and stirred continuously. The addition amount of the composite collector is 50 μL / L, and the stirring time is 3 min. Then a composite frother is added and stirred continuously. The addition amount of the composite frother is 10 μL / L, and the stirring time is 3 min; After stirring, the air inlet valve is opened to inflate and scrape the foam until there is no obvious froth clean coal, and flotation clean coal and tail coal are obtained;

[0052] S3. The obtained flotation clean coal and tail coal are respectively dried and weighed. The yield of the obtained flotation clean coal is 35.69%, the ash content is 13.21%, and the combustible matter recovery rate is 72.47%.

[0053] Example 2

[0054] A low-rank coal composite flotation reagent, specifically a composite collector and a composite foaming agent. The components of the composite collector are as follows by mass fraction: kerosene 50%, n-dodecane 10%, oleic acid 12%, dimer acid 4%, sodium stearate 2%, terpineol 5%, diethyl phthalate 11%, alkylphenol polyoxyethylene ether 1.5%, Span-80 1.5%, trioctyl phosphate 2%, 2-ethylhexanol 1%.

[0055] The components of the composite foaming agent are as follows by mass fraction: terpineol 40%, pine oil 47%, sec-octanol 10%, α-olefin sulfonate 3%.

[0056] The preparation method of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0057] (1) Solution preparation: Mix the components of the composite collector and the composite foaming agent respectively according to the ratio, and after mixing evenly, obtain the collector solution and the foaming agent solution.

[0058] (2) Ultrasonic emulsification: Place the obtained collector solution and foaming agent solution under ultrasonic conditions for emulsification respectively. The ultrasonic frequency is 15 kHz, and the ultrasonic emulsification time is 1 h to obtain the collector mixture and the foaming agent mixture for standby.

[0059] (3) Deep emulsification: Place the collector mixture and the foaming agent mixture in a hydrothermal reaction kettle and heat to 65 °C, then stir for 30 min for deep emulsification to obtain the composite collector and the composite foaming agent.

[0060] The application of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0061] S1. Crush and grind the low-rank coal blocks to a particle size of ≤ 0.5 mm, add water to the obtained coal powder for pulp preparation, and obtain a coal slurry with a concentration of 108 g / L for standby.

[0062] S2. Place the coal slurry in a flotation machine with a rotation speed of 1900 r / min for pre-stirring. The pre-stirring time is 3 min, then add the composite collector and continue to stir. The addition amount of the composite collector is 50 μL / L, and the stirring time is 3 min. Then add the composite foaming agent and continue to stir. The addition amount of the composite foaming agent is 15 μL / L, and the stirring time is 3 min. After stirring, open the air inlet valve to inflate and scrape the foam until there is no obvious froth clean coal, and obtain the flotation clean coal and tail coal.

[0063] S3. Dry and weigh the obtained flotation clean coal and tail coal respectively. The yield of the obtained flotation clean coal is 39.98%, the ash content is 11.2%, and the combustible matter recovery rate is 75.61%.

[0064] Example 3

[0065] A low-rank coal composite flotation reagent, specifically a composite collector and a composite foaming agent. The components of the composite collector are calculated by mass fraction, including 50% kerosene, 10% n-dodecane, 14% oleic acid, 3% dimer acid, 1% sodium stearate, 6% terpineol, 10% diethyl phthalate, 0.5% alkylphenol polyoxyethylene ether, 1.5% Span-80, 2% tributyl phosphate, and 2% 2-ethylhexanol;

[0066] The components of the composite foaming agent are calculated by mass fraction, including 40% terpineol, 47% pine oil, 10% - 15% sec-octanol, and 3% α-olefin sulfonate.

[0067] The preparation method of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0068] (1) Solution preparation: According to the components of the composite collector and the composite foaming agent, they are proportioned respectively, and after mixing evenly, a collector solution and a foaming agent solution are obtained;

[0069] (2) Ultrasonic emulsification: The obtained collector solution and foaming agent solution are respectively placed under ultrasonic conditions for emulsification. The ultrasonic frequency is 25 kHz, and the ultrasonic emulsification time is 1 h to obtain a collector mixture and a foaming agent mixture for standby;

[0070] (3) Deep emulsification: The collector mixture and the foaming agent mixture are respectively placed in a hydrothermal reaction kettle and heated to 60 °C, and then stirred for 30 min for deep emulsification to obtain a composite collector and a composite foaming agent.

[0071] The application of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0072] S1. The low-rank coal blocks are crushed and ground to a particle size ≤ 0.5 mm, and the obtained coal powder is mixed with water for pulp preparation to obtain a coal slurry with a concentration of 150 g / L for standby;

[0073] S2. The coal slurry is placed in a flotation machine with a rotation speed of 1900 r / min for pre-stirring, and the pre-stirring time is 2 min. Then, a composite collector is added and stirred continuously. The addition amount of the composite collector is 50 μL / L, and the stirring time is 4 min. Then, a composite foaming agent is added and stirred continuously. The addition amount of the composite foaming agent is 15 μL / L, and the stirring time is 3 min; After stirring, the air inlet valve is opened to inflate and scrape the foam until there is no obvious foam clean coal to obtain flotation clean coal and tail coal;

[0074] S3. The obtained flotation clean coal and tail coal are respectively dried and weighed. The yield of the obtained flotation clean coal is 44.67%, the ash content is 13.12%, and the combustible matter recovery rate is 75.62%.

[0075] Example 4

[0076] A low-rank coal composite flotation reagent, specifically a composite collector and a composite frother. The components of the composite collector are calculated by mass fraction and include 45% kerosene, 10% n-dodecane, 14% oleic acid, 6% dimer acid, 1% sodium stearate, 10% terpineol, 10% diethyl phthalate, 0.5% alkylphenol polyoxyethylene ether, 1.5% Span-80, 1% tributyl phosphate, and 1% 2-ethylhexanol;

[0077] The components of the composite frother are calculated by mass fraction and include 40% terpineol, 47% pine oil, 10% sec-octanol, and 3% α-olefin sulfonate.

[0078] The preparation method of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0079] (1) Solution preparation: Mix according to the components of the composite collector and the composite frother respectively, and after mixing evenly, obtain the collector solution and the frother solution;

[0080] (2) Ultrasonic emulsification: Place the obtained collector solution and frother solution under ultrasonic conditions for emulsification respectively. The ultrasonic frequency is 25 kHz, and the ultrasonic emulsification time is 0.75 h to obtain the collector mixture and the frother mixture for standby;

[0081] (3) Deep emulsification: Place the collector mixture and the frother mixture in a hydrothermal reaction kettle and heat to 65 °C, then stir for 40 min for deep emulsification to obtain the composite collector and the composite frother.

[0082] The application of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0083] S1. Crush and grind the low-rank coal blocks to a particle size ≤ 0.5 mm, add water to the obtained coal powder for pulp preparation, and obtain a coal slurry with a concentration of 108 g / L for standby;

[0084] S2. Place the coal slurry in a flotation machine with a rotation speed of 1900 r / min for pre-stirring, the pre-stirring time is 3 min, then add the composite collector and continue stirring. The addition amount of the composite collector is 80 μL / L, and the stirring time is 3 min. Then add the composite frother and continue stirring. The addition amount of the composite frother is 30 μL / L, and the stirring time is 4 min; after stirring, open the air inlet valve to inflate and scrape the foam until there is no obvious foam clean coal, and obtain the flotation clean coal and tail coal;

[0085] S3. Dry and weigh the obtained flotation clean coal and tail coal respectively. The yield of the obtained flotation clean coal is 51.34%, the ash content is 13.67%, and the combustible matter recovery rate is 70.93%.

[0086] Example 5

[0087] A low-rank coal composite flotation reagent, specifically a composite collector and a composite foaming agent. The components of the composite collector are calculated by mass fraction and include 45% kerosene, 15% n-dodecane, 14% oleic acid, 3% dimer acid, 1% sodium stearate, 8% terpineol, 10% diethyl phthalate, 0.5% alkylphenol polyoxyethylene ether, 1.5% Span-80, 1% tributyl phosphate, and 1% 2-ethylhexanol;

[0088] The components of the composite foaming agent are calculated by mass fraction and include 47% terpineol, 40% pine oil, 10% sec-octanol, and 3% α-olefin sulfonate.

[0089] The preparation method of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0090] (1) Solution preparation: According to the components of the composite collector and the composite foaming agent, they are proportioned respectively, and after mixing evenly, a collector solution and a foaming agent solution are obtained;

[0091] (2) Ultrasonic emulsification: The obtained collector solution and foaming agent solution are respectively placed under ultrasonic conditions for emulsification. The ultrasonic frequency is 20 kHz, and the ultrasonic emulsification time is 1 h to obtain a collector mixture and a foaming agent mixture for standby;

[0092] (3) Deep emulsification: The collector mixture and the foaming agent mixture are respectively placed in a hydrothermal reaction kettle and heated to 55 °C, and then stirred for 50 min for deep emulsification to obtain a composite collector and a composite foaming agent.

[0093] The application of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0094] S1. The low-rank coal blocks are crushed and ground to a particle size ≤ 0.5 mm, and the obtained coal powder is mixed with water for pulp preparation to obtain a coal slurry with a concentration of 200 g / L for standby;

[0095] S2. The coal slurry is placed in a flotation machine with a rotation speed of 2000 r / min for pre-stirring. The pre-stirring time is 4 min, and then a composite collector is added and stirred continuously. The addition amount of the composite collector is 100 μL / L, and the stirring time is 2 min. Then a composite foaming agent is added and stirred continuously. The addition amount of the composite foaming agent is 40 μL / L, and the stirring time is 2 min; After stirring, the air inlet valve is opened to inflate and scrape the foam until there is no obvious froth clean coal, and flotation clean coal and tail coal are obtained;

[0096] S3. The obtained flotation clean coal and tail coal are respectively dried and weighed. The yield of the obtained flotation clean coal is 49.33%, the ash content is 14.27%, and the combustible recovery rate is 70.21%.

[0097] Example 6

[0098] A low-rank coal composite flotation reagent, specifically a composite collector and a composite frother. The components of the composite collector, calculated by mass fraction, include 55% kerosene, 10% n-dodecane, 7% oleic acid, 5% dimer acid, 2% sodium stearate, 7% terpineol, 10% diethyl phthalate, 0.5% alkylphenol polyoxyethylene ether, 1.5% Span-80, 1% tributyl phosphate, and 1% 2-ethylhexanol;

[0099] The components of the composite frother, calculated by mass fraction, include 40% terpineol, 47% pine oil, 10% sec-octanol, and 3% α-olefin sulfonate.

[0100] The preparation method of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0101] (1) Solution preparation: According to the components of the composite collector and the composite frother, respectively, make the ratios, mix them evenly to obtain the collector solution and the frother solution;

[0102] (2) Ultrasonic emulsification: Place the obtained collector solution and frother solution under ultrasonic conditions for emulsification respectively. The ultrasonic frequency is 25 kHz, and the ultrasonic emulsification time is 1 h to obtain the collector mixture and the frother mixture for standby;

[0103] (3) Deep emulsification: Place the collector mixture and the frother mixture in a hydrothermal reaction kettle and heat to 70 °C, then stir for 30 min for deep emulsification to obtain the composite collector and the composite frother.

[0104] The application of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0105] S1. Crush and grind the low-rank coal blocks to a particle size ≤ 0.5 mm, add water to the obtained coal powder for pulp preparation to obtain a coal slurry with a concentration of 108 g / L for standby;

[0106] S2. Place the coal slurry in a flotation machine with a rotation speed of 1800 r / min for pre-stirring. The pre-stirring time is 3 min, then add the composite collector and continue stirring. The addition amount of the composite collector is 100 μL / L, and the stirring time is 3 min. Then add the composite frother and continue stirring. The addition amount of the composite frother is 40 μL / L, and the stirring time is 3 min; After stirring, open the air inlet valve to inflate and scrape the foam until there is no obvious froth clean coal to obtain the flotation clean coal and tail coal;

[0107] S3. Dry and weigh the obtained flotation clean coal and tail coal respectively. The yield of the obtained flotation clean coal is 54.22%, the ash content is 13.09%, and the combustible matter recovery rate is 73.55%.

[0108] Comparative Example 1

[0109] A single flotation reagent for low-rank coal uses kerosene as the single collector and sec-octanol as the single frother.

[0110] The application of the above single flotation reagent for low-rank coal specifically includes the following steps:

[0111] S1. Crush and grind low-rank coal blocks to a particle size ≤ 0.5 mm, add water to the obtained coal powder for pulp preparation, and obtain a coal slurry with a concentration of 108 g / L for standby;

[0112] S2. Place the coal slurry in a flotation machine with a rotation speed of 1900 r / min for pre-stirring for 3 min. Then add a composite collector and continue stirring. The addition amount of the composite collector is 50 μL / L, and the stirring time is 3 min. Then add a composite frother and continue stirring. The addition amount of the composite frother is 15 μL / L, and the stirring time is 3 min; After stirring, open the air inlet valve to introduce air and scrape the foam until there is no obvious froth concentrate, obtaining flotation concentrate and tail coal;

[0113] S3. Dry and weigh the obtained flotation concentrate and tail coal respectively. The yield of the obtained flotation concentrate is 6.22%, the ash content is 47.09%, and the combustible matter recovery rate is 4.47%.

[0114] Comparative Example 2

[0115] A single flotation reagent for low-rank coal uses kerosene as the single collector and terpineol as the single frother.

[0116] The application of the above single flotation reagent for low-rank coal specifically includes the following steps:

[0117] S1. Crush and grind low-rank coal blocks to a particle size ≤ 0.5 mm, add water to the obtained coal powder for pulp preparation, and obtain a coal slurry with a concentration of 108 g / L for standby;

[0118] S2. Place the coal slurry in a flotation machine with a rotation speed of 1900 r / min for pre-stirring for 3 min. Then add a composite collector and continue stirring. The addition amount of the composite collector is 50 μL / L, and the stirring time is 3 min. Then add a composite frother and continue stirring. The addition amount of the composite frother is 15 μL / L, and the stirring time is 3 min; After stirring, open the air inlet valve to introduce air and scrape the foam until there is no obvious froth concentrate, obtaining flotation concentrate and tail coal;

[0119] S3. Dry and weigh the obtained flotation concentrate and tail coal respectively. The yield of the obtained flotation concentrate is 8.22%, the ash content is 34.01%, and the combustible matter recovery rate is 11.47%.

[0120] Comparative Example 3

[0121] A low-rank coal single flotation reagent uses oleic acid as the single collector and terpineol as the single frother.

[0122] The application of the above low-rank coal single flotation reagent specifically includes the following steps:

[0123] S1. Crush and grind the low-rank coal blocks to a particle size of ≤ 0.5 mm, add water to the obtained coal powder for pulp preparation, and obtain a coal slurry with a concentration of 108 g / L for standby;

[0124] S2. Place the coal slurry in a flotation machine with a rotational speed of 1900 r / min for pre-stirring for 3 min. Then add a composite collector and continue stirring. The addition amount of the composite collector is 50 μL / L, and the stirring time is 3 min. Then add a composite frother and continue stirring. The addition amount of the composite frother is 15 μL / L, and the stirring time is 3 min. After stirring, open the air inlet valve to introduce air and scrape the foam until there is no obvious froth concentrate, obtaining flotation concentrate and tail coal;

[0125] S3. Dry and weigh the obtained flotation concentrate and tail coal respectively. The yield of the obtained flotation concentrate is 17.98%, the ash content is 12.89%, and the combustible matter recovery rate is 29.76%.

[0126] Comparative Example 4

[0127] A low-rank coal single flotation reagent uses oleic acid as the single collector and pine oil as the single frother.

[0128] The application of the above low-rank coal single flotation reagent specifically includes the following steps:

[0129] S1. Crush and grind the low-rank coal blocks to a particle size of ≤ 0.5 mm, add water to the obtained coal powder for pulp preparation, and obtain a coal slurry with a concentration of 108 g / L for standby;

[0130] S2. Place the coal slurry in a flotation machine with a rotational speed of 1900 r / min for pre-stirring for 3 min. Then add a composite collector and continue stirring. The addition amount of the composite collector is 50 μL / L, and the stirring time is 3 min. Then add a composite frother and continue stirring. The addition amount of the composite frother is 15 μL / L, and the stirring time is 3 min. After stirring, open the air inlet valve to introduce air and scrape the foam until there is no obvious froth concentrate, obtaining flotation concentrate and tail coal;

[0131] S3. Dry and weigh the obtained flotation concentrate and tail coal respectively. The yield of the obtained flotation concentrate is 10.2%, the ash content is 20.89%, and the combustible matter recovery rate is 16.40%.

[0132] Comparative Example 5

[0133] A single flotation reagent for low-rank coal, using fatty acid methyl ester as the single collector and pine oil as the single frother.

[0134] The application of the above single flotation reagent for low-rank coal specifically includes the following steps:

[0135] S1. Crush and grind low-rank coal blocks to a particle size of ≤0.5 mm, add water to the obtained coal powder for pulp preparation, and obtain a coal slurry with a concentration of 108 g / L for standby;

[0136] S2. Place the coal slurry in a flotation machine with a rotational speed of 1900 r / min for pre-stirring for 3 min. Then add a composite collector and continue stirring. The addition amount of the composite collector is 50 μL / L, and the stirring time is 3 min. Then add a composite frother and continue stirring. The addition amount of the composite frother is 15 μL / L, and the stirring time is 3 min; after stirring, open the air inlet valve to introduce air and scrape the foam until there is no obvious froth clean coal, and obtain flotation clean coal and tail coal;

[0137] S3. Dry and weigh the obtained flotation clean coal and tail coal respectively. The yield of the obtained flotation clean coal is 14.27%, the ash content is 14.99%, and the combustible matter recovery rate is 24.48%.

[0138] Comparative Example 6

[0139] A composite flotation reagent for low-rank coal, specifically a single collector and a composite frother. The single collector is kerosene.

[0140] The components of the composite frother are calculated by mass fraction, including 40% terpineol, 47% pine oil, 10% sec-octanol, and 3% α-olefin sulfonate.

[0141] The preparation method of the above composite frother for low-rank coal specifically includes the following steps:

[0142] (1) Solution preparation: Mix according to the components of the composite collector and the composite frother respectively, and after mixing evenly, obtain a collector solution and a frother solution;

[0143] The application of the above single collector and composite frother for low-rank coal specifically includes the following steps:

[0144] S1. Crush and grind low-rank coal blocks to a particle size of ≤0.5 mm, add water to the obtained coal powder for pulp preparation, and obtain a coal slurry with a concentration of 108 g / L for standby;

[0145] S2. Place the coal slurry in a flotation machine with a rotation speed of 1900 r / min for pre-stirring for 3 min. Then add a composite collector and continue stirring. The addition amount of the composite collector is 50 μL / L, and the stirring time is 3 min. Then add a composite frother and continue stirring. The addition amount of the composite frother is 15 μL / L, and the stirring time is 3 min. After stirring, open the air inlet valve to introduce air and scrape the foam until there is no obvious froth clean coal, obtaining flotation clean coal and tail coal;

[0146] S3. Dry and weigh the obtained flotation clean coal and tail coal respectively. The yield of the obtained flotation clean coal is 28.1%, the ash content is 19.81%, and the combustible matter recovery rate is 63.05%.

[0147] Comparative Example 7

[0148] A low-rank coal composite flotation reagent, specifically a composite collector and a single frother. The components of the composite collector are calculated by mass fraction, including 50% kerosene, 10% n-dodecane, 14% oleic acid, 3% dimer acid, 1% sodium stearate, 6% terpineol, 10% diethyl phthalate, 0.5% alkylphenol polyoxyethylene ether, 1.5% Span-80, 2% tributyl phosphate, and 2% 2-ethylhexanol;

[0149] The single frother is terpineol.

[0150] The preparation method of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0151] (1) Solution preparation: Mix according to the components of the composite collector and the composite frother respectively, and mix evenly to obtain a collector solution and a frother solution;

[0152] (2) Ultrasonic emulsification: Place the obtained collector solution and frother solution under ultrasonic conditions for emulsification. The ultrasonic frequency is 25 kHz, and the ultrasonic emulsification time is 1 h to obtain a collector mixture and a frother mixture for standby;

[0153] (3) Deep emulsification: Place the collector mixture and the frother mixture in a hydrothermal reaction kettle and heat to 65 °C, then stir for 30 min for deep emulsification to obtain a composite collector and a composite frother.

[0154] The application of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0155] S1. Crush and grind low-rank coal blocks to a particle size of ≤0.5 mm, add water to the obtained coal powder for pulp preparation, and obtain a coal slurry with a concentration of 108 g / L for standby;

[0156] S2. Place the coal slurry in a flotation machine with a rotational speed of 1900 r / min for pre-stirring for 3 min. Then add the composite collector and continue stirring. The addition amount of the composite collector is 50 μL / L, and the stirring time is 3 min. Then add the composite foaming agent and continue stirring. The addition amount of the composite foaming agent is 15 μL / L, and the stirring time is 3 min. After stirring, open the air inlet valve to introduce air and scrape the foam until there is no obvious froth concentrate coal, obtaining the flotation concentrate coal and tail coal;

[0157] S3. Dry and weigh the obtained flotation concentrate coal and tail coal respectively. The yield of the obtained flotation concentrate coal is 29.77%, the ash content is 22.16%, and the combustible matter recovery rate is 55.32%.

[0158] Comparative Example 8

[0159] A low-rank coal composite flotation reagent, specifically a composite collector and a single foaming agent. The components of the composite collector are calculated by mass fraction, including 50% kerosene, 10% n-dodecane, 14% oleic acid, 5% dimer acid, 1% sodium stearate, 4% terpineol, 10% diethyl phthalate, 0.5% alkylphenol polyoxyethylene ether, 1.5% Span-80, 2% tributyl phosphate, 2% 2-ethylhexanol;

[0160] The single foaming agent is sec-octanol.

[0161] The preparation method of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0162] (1) Solution preparation: Make the ratio according to the components of the composite collector and the composite foaming agent respectively, and mix evenly to obtain the collector solution and the foaming agent solution;

[0163] (2) Ultrasonic emulsification: Place the obtained collector solution and foaming agent solution under ultrasonic conditions for emulsification respectively. The ultrasonic frequency is 25 kHz, and the ultrasonic emulsification time is 1 h to obtain the collector mixture and the foaming agent mixture for standby;

[0164] (3) Deep emulsification: Place the collector mixture and the foaming agent mixture in a hydrothermal reaction kettle and heat to 65 °C, then stir for 30 min for deep emulsification to obtain the composite collector and the composite foaming agent.

[0165] The application of the above low-rank coal composite flotation reagent specifically includes the following steps:

[0166] S1. Crush and grind the low-rank coal blocks to a particle size ≤ 0.5 mm, add water to the obtained coal powder for pulp preparation, and obtain a coal slurry with a concentration of 108 g / L for standby;

[0167] S2. Place the coal slurry in a flotation machine with a rotational speed of 1900 r / min for pre-stirring. The pre-stirring time is 3 min. Subsequently, add a composite collector and continue stirring. The addition amount of the composite collector is 50 μL / L, and the stirring time is 3 min. Then add a composite frother and continue stirring. The addition amount of the composite frother is 15 μL / L, and the stirring time is 3 min. After stirring, open the air inlet valve to introduce air and scrape the foam until there is no obvious froth concentrate coal, obtaining flotation concentrate coal and tail coal;

[0168] S3. Dry and weigh the obtained flotation concentrate coal and tail coal respectively. The yield of the obtained flotation concentrate coal is 19.03%, the ash content is 24.16%, and the combustible matter recovery rate is 53.93%.

Claims

1. A composite flotation agent for low-rank coal, characterized in that: Specifically, it is a composite collector and a composite foaming agent. The components of the composite collector, calculated by mass fraction, include kerosene 45% to 55%, n-dodecane 10% to 15%, oleic acid 7% to 14%, dimer acid 2% to 6%, sodium stearate 1% to 5%, terpineol 3% to 10%, diethyl phthalate 10% to 18%, alkylphenol polyoxyethylene ether 0.5% to 3%, Span-80 1.5% to 6%, trioctyl phosphate 1% to 4%, and 2-ethylhexanol 1% to 3%; The components of the composite foaming agent include, by mass fraction, 40% to 60% of terpineol, 40% to 60% of pine oil, 10% to 15% of secondary octanol, and 3% to 6% of sodium α-olefin sulfonate.

2. The method for preparing a composite flotation agent for low-rank coal according to claim 1, characterized in that: The specific steps include: (1) Solution preparation: The composite collector and the composite foaming agent are respectively prepared in proportion and mixed evenly to obtain a collector solution and a foaming agent solution; (2) Ultrasonic emulsification: The obtained collector solution and foaming agent solution are respectively placed under ultrasonic conditions for emulsification to obtain a collector mixed solution and a foaming agent mixed solution for standby use; (3) Deep emulsification: The collector mixture and the foaming agent mixture are placed in a hydrothermal reactor for heating, and then stirred for deep emulsification to obtain a composite collector and a composite foaming agent.

3. The method for preparing a composite flotation agent for low-rank coal according to claim 2, characterized in that: In the step (2), the ultrasonic frequency is 15kHz to 25kHz, and the ultrasonic emulsification time is 0.5h to 1h.

4. The method for preparing a composite flotation agent for low-rank coal according to claim 2, characterized in that: In the step (3), the collector mixture and the foaming agent mixture are heated to 50°C to 85°C.

5. The method for preparing a composite flotation agent for low-rank coal according to claim 2, characterized in that: In the step (3), the stirring time during the deep emulsification process is 25 min to 60 min.

6. The use of a composite flotation agent for low-rank coal according to claim 1, characterized in that: The specific steps include: S1. The low-rank coal blocks are crushed and ground to a particle size of ≤0.5 mm, and the resulting coal powder is slurried with water to obtain a coal slurry for standby use; S2. The coal slurry is placed in a flotation machine for pre-stirring, and then a composite collector is added to continue stirring, and then a composite frother is added. After stirring, the air valve is opened to air-scrape the foam until there is no obvious foam clean coal, and the flotation clean coal and tail coal are obtained; S3. Dry and weigh the obtained flotation clean coal and tail coal respectively, and calculate the clean coal yield, ash content and combustible recovery rate.

7. The use of a composite flotation agent for low-rank coal according to claim 5, characterized in that: In step S1, the concentration of the coal slurry is 100 g / L to 200 g / L, and the rotation speed of the flotation machine is 1800 r / min to 2000 r / min.

8. The use of a composite flotation agent for low-rank coal according to claim 5, characterized in that: In the step S2, the pre-stirring time is 2 min to 4 min, the added amount of the composite collector is 30 μL / L to 100 μL / L, and the stirring time is 2 min to 4 min.

9. The use of a composite flotation agent for low-rank coal according to claim 5, characterized in that: In the step S2, the amount of the composite foaming agent added is 10 μL / L to 40 μL / L, and the mixture is stirred for 2 min to 4 min after being added.

10. The use of a composite flotation agent for low-rank coal according to claim 5, characterized in that: In step S3, the yield of the flotation clean coal is 35% to 55%, the ash content is 10% to 15%, and the recovery rate of combustibles is 70% to 77%.