A new type of composite floatation agent for coal mine and a preparation method thereof

Abstract

The application discloses a novel composite floatation agent for coal mines and a preparation method thereof, and relates to the technical field of floatation agents, and the technical scheme is that, at normal temperature, an emulsifier is mixed with water, and high-speed stirring is conducted until the emulsifier is completely dissolved; the floatation agent is slowly added into the mixed solution, stirring is conducted until a uniform dispersed emulsion is formed, a stabilizing agent is continuously added and stirring is conducted until the emulsion is stable; the stable emulsion is poured into a homogenizer, low pressure and high pressure are adjusted, and the novel composite floatation agent is prepared through one-time homogenization. The hydrophobic modified hydroxyethyl cellulose is compounded with other floatation agents, the hydrophobic functional groups play a role in collecting performance and have a synergistic effect, the cellulose functional groups effectively disperse solid particles of ore pulp, the contact area between minerals and bubbles is increased, the foam stability is enhanced, and the collecting performance is improved. Through optimization of emulsifier proportioning and homogenization and emulsification, the dispersivity and collecting effect of the floatation agent are significantly improved, the agent has strong stability and low viscosity, and is convenient for on-site use.

Description

Technical Field

[0001] This invention relates to the field of flotation agent technology, and in particular to a novel composite flotation agent for coal mines and its preparation method. Background Technology

[0002] Flotation technology in mineral processing is one of the most widely used separation technologies, extensively applied in the beneficiation and concentrate extraction of minerals such as coal and metallic ores. Flotation primarily relies on the use of flotation reagents to adjust the surface properties of minerals, promoting the binding of minerals with air bubbles, thereby achieving mineral separation. During the flotation process, flotation reagents, as key components, not only improve the surface properties of minerals, making them easier to float, but also directly affect the flotation efficiency and mineral recovery rate. The types and application methods of flotation reagents have always been an important research direction in mineral processing technology, especially in the coal mining industry. With the increasingly stringent requirements for coal beneficiation, the development of composite flotation reagents has gradually become a research hotspot in the industry.

[0003] Flotation reagents are classified according to their chemical properties and functions, typically including collectors, frothers, emulsifiers, and stabilizers. Among these, collectors and frothers are the core components of flotation reagents, directly determining mineral collection and bubble generation during the flotation process. Currently, commonly used collectors are mostly oil-based or fatty acid-based reagents, such as kerosene and light diesel oil. These reagents have strong hydrophobicity, enabling them to adsorb onto the mineral surface and form an oleophilic film, thereby improving the flotation properties of mineral particles. However, despite the important role these traditional reagents play in the flotation process, their physical and chemical limitations, particularly poor dispersibility and high reagent consumption, remain significant factors affecting flotation efficiency. Furthermore, due to their strong hydrophobicity, traditional flotation reagents have poor dispersibility, especially in poor water quality or with fine mineral particles, resulting in unsatisfactory collection effects, leading to low flotation efficiency and reduced economic benefits.

[0004] With increasing focus on flotation efficiency and economic benefits, the development of composite flotation reagents has emerged. Composite flotation reagents combine the advantages of multiple reagents, improving their dispersibility and stability in the slurry, thereby increasing flotation efficiency and mineral recovery. In recent years, research on composite flotation reagents has gradually increased, especially in the field of coal mine beneficiation. Due to their strong adaptability and low operating costs, composite flotation reagents have become a key research focus in flotation reagents. The advantage of composite flotation reagents lies in their ability to reduce the drawbacks of traditional reagents, such as high consumption, poor dispersibility, and potential environmental pollution, by optimizing the reagent composition. Therefore, composite flotation reagents are considered an important technological direction for solving the problems of efficiency and cost in coal mine flotation.

[0005] Although flotation technology is widely used in mineral processing, existing flotation reagents still have many problems in terms of type and performance, limiting the further development of flotation technology. Traditional flotation reagents are mostly based on oils and fatty acids. These reagents have strong hydrophobicity, resulting in poor dispersibility in the pulp. Especially when processing fine-grained coal, low-rank coal, and other minerals, the flotation effect is often unsatisfactory, with poor collection and selectivity, which in turn affects the improvement of mineral recovery and concentrate grade. Although composite flotation reagents have improved in reagent formulation, their problems of poor emulsification stability and poor dispersion effect have not been effectively solved, directly affecting the economic benefits of the flotation process.

[0006] The market offers a wide variety of emulsifiers, but most fail to achieve ideal emulsification when used in combination with flotation reagents. Common emulsification methods such as mechanical stirring and ultrasonic emulsification, while improving reagent dispersibility to some extent, result in poor post-emulsification stability, leading to stratification or sedimentation and reduced flotation efficiency. Furthermore, existing emulsifiers have limitations in adapting to different coal qualities and mineral characteristics, and their complex formulations require high-precision control, increasing both production costs and operational difficulty. Therefore, selecting suitable emulsifiers and optimizing the emulsification process are crucial factors affecting the effectiveness of composite flotation agents.

[0007] Although existing technologies have attempted to optimize the type and proportion of emulsifiers and adjust the emulsification process, many challenges remain. For example, during mechanical stirring or ultrasonic emulsification, the reagents exhibit poor stability, are prone to stratification, and require large quantities, posing environmental pollution risks. Existing emulsifiers have high requirements for water quality, resulting in poor stability in the pulp and affecting reagent release, further leading to unsatisfactory flotation results. Therefore, existing technologies still have significant shortcomings in improving the emulsification stability of flotation reagents, enhancing their dispersion in the pulp, and improving collection efficiency.

[0008] To address the shortcomings of existing technologies, this invention aims to solve the problems of poor emulsification, instability, and low flotation efficiency in flotation reagents. In particular, ensuring uniform dispersion and maintaining stability of flotation reagents in the pulp during preparation and use is crucial for improving flotation efficiency. Existing emulsifiers often fail to meet the requirements of specific coal qualities and mineral characteristics, resulting in poor dispersibility and unstable collection in the pulp, thus affecting flotation efficiency. Therefore, a new flotation reagent and preparation method are needed that can improve reagent dispersibility and stability while ensuring high collection and foaming properties, thereby significantly improving mineral recovery and concentrate grade, ultimately enhancing the economic benefits of the flotation process. Summary of the Invention

[0009] To achieve the above-mentioned objectives and address the aforementioned technical problems, this invention provides a novel composite flotation agent for coal mines, wherein the composite flotation agent comprises the following components in parts by weight:

[0010] 50-60 parts of flotation reagent

[0011] Emulsifier 0.2-1.0 parts

[0012] Stabilizer 0.2-1.0 parts

[0013] Water 38-59.6 parts.

[0014] Preferably, the flotation agent comprises: hydrophobically modified hydroxyethyl cellulose, No. 2 flotation oil, and tall oil, and the weight ratio of each component is (0.01-0.05):1:1.

[0015] Preferably, the emulsifier includes one or more of octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, and sodium lauryl ether sulfate.

[0016] Preferably, the stabilizer includes one or more of polyethylene glycol stearate, polyoxyethylene stearate, and polyoxypropylene ethylene glycerol ether.

[0017] This invention also provides a method for preparing a novel composite flotation agent for coal mines, the method comprising the following steps:

[0018] S1 is prepared by mixing 0.2-1.0 parts of emulsifier with 38-59.6 parts of water at room temperature, using a high-speed mixer at a speed of 500-700 rpm for 15-30 minutes until the emulsifier is completely dissolved, thus obtaining a mixture.

[0019] S2. Slowly add 50-60 parts of flotation agent to the mixture and stir for 5-10 minutes to form a uniformly dispersed emulsion. Continue to add 0.1-1.0 parts of stabilizer and stir for 10 minutes until the emulsion reaches a stable state to obtain a stable emulsion.

[0020] S3. The stable emulsion is poured into a homogenizer. First, the low pressure of the homogenizer is adjusted, and then the high pressure of the homogenizer is adjusted. The homogenization cycle is repeated once to obtain the novel composite flotation agent.

[0021] Preferably, the flotation agent in step S2 includes: hydrophobically modified hydroxyethyl cellulose, No. 2 flotation oil, and tall oil, and the weight ratio of each component is (0.01-0.05):1:1.

[0022] Preferably, the emulsifier includes one or more of octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, and sodium lauryl ether sulfate.

[0023] Preferably, the stabilizer includes one or more of polyethylene glycol stearate, polyoxyethylene stearate, and polyoxypropylene ethylene glycerol ether.

[0024] Preferably, the low pressure of the homogenizer is adjusted to 1-2 MPa, and the high pressure is adjusted to 10-15 MPa.

[0025] The beneficial effects of the technical solution provided by this invention are as follows:

[0026] Using hydrophobically modified hydroxyethyl cellulose as a flotation agent, when combined with other flotation agents, can not only leverage the collecting performance of the hydrophobic functional groups, but also achieve synergistic effects with other flotation agents. Furthermore, the introduction of its cellulose functional groups enables it to effectively disperse solid particles in the slurry, increase the contact area between mineral particles and bubbles, separate target minerals from other impurities, enhance foam stability, and improve collecting performance.

[0027] By optimizing the composition and ratio of the emulsifier and employing a homogenized emulsification method, the dispersion and collection effect of flotation reagents in the pulp were successfully improved. The reagent preparation can be carried out at room temperature, and the resulting composite flotation agent has a stability of up to one year and a low viscosity (≤30 mPa·s), facilitating on-site pumping.

[0028] When used, the comprehensive reagent consumption is ≤180g / t raw coal, the yield of flotation clean coal can reach more than 80%, the ash content of flotation clean coal is between 10-12%, and the ash content of tailings can reach more than 70%. It has excellent flotation performance and can save about 50% of kerosene consumption.

[0029] The reagent preparation is simple, highly operable, and environmentally friendly, non-toxic, odorless, free of impurities and sediment, easy to defoam, and does not affect the operation of circulating water. This will help improve the economic efficiency and environmental performance of mineral processing, providing a new technical means for mineral flotation processes in coal mines. Attached Figure Description

[0030] Figure 1 The image shows a product from an embodiment of the present invention.

[0031] Figure 2 These are application scenario photos of embodiments of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] Example 1

[0034] New composite flotation agent for coal mines:

[0035] The composite flotation agent is prepared according to the following ratio: 60 parts flotation agent, 0.5 parts emulsifier, 38.5 parts water, and 1 part stabilizer. The flotation agent is prepared by hydrophobically modified hydroxyethyl cellulose, No. 2 flotation oil, and tall oil in a weight ratio of 0.05:1:1.

[0036] At room temperature, sodium lauryl ether sulfate and water are first stirred in a high-speed mixer at a speed of 500 rpm for 30 minutes until the emulsifier is completely dissolved. The stirring speed is maintained, and the flotation agent is slowly added. After stirring for 10 minutes, a uniformly dispersed emulsion is formed. Polyethylene glycol stearate is then added, and stirring is continued for another 10 minutes to obtain a temporarily stable emulsion.

[0037] The emulsion was immediately poured into a homogenizer. The low pressure of the homogenizer was first adjusted to 0.8, 2, and 3 MPa, and then the high pressure of the homogenizer was adjusted to 8, 10, 15, and 20 MPa. The homogenization cycle was repeated once to obtain a new type of composite flotation agent.

[0038] Table 1 Experimental parameters and data

[0039]

[0040]

[0041] As can be seen from the table, when the homogenizer is at a low pressure of 1 and 2 MPa, the dynamic viscosity of the homogenized product is generally lower than that at low pressures of 0.8 and 3 MPa, and no stratification occurs after standing for 24 hours. However, when the high pressure is 8 MPa, a skin is easily formed on the surface. As the high pressure increases, the viscosity gradually increases. Therefore, the preferred low pressure and high pressure are 1-2 MPa and 10-15 MPa, respectively.

[0042] The experiment also found that as the number of homogenization cycles increased, the viscosity of the product increased slightly, but the stability was not significantly enhanced. Therefore, one homogenization cycle is sufficient.

[0043] Example 2:

[0044] The composite flotation agent is prepared according to the following ratio: 40-60 parts flotation agent, 0.5 parts emulsifier, 38.5-58.5 parts water, and 1.0 part stabilizer. The flotation agent is prepared by mixing hydrophobically modified hydroxyethyl cellulose, No. 2 flotation oil, and tall oil in a weight ratio of 0.05:1:1.

[0045] At room temperature, sodium lauryl ether sulfate and water were first mixed in a high-speed mixer at 500 rpm for 30 minutes until the emulsifier was completely dissolved. Maintaining this mixing speed, the flotation agent was slowly added, and after 10 minutes of mixing, a uniformly dispersed emulsion was formed. Polyethylene glycol stearate was then added, and mixing continued for another 10 minutes to obtain a temporarily stable emulsion. The emulsion was immediately poured into a homogenizer. The low pressure of the homogenizer was first adjusted to 2 MPa, and then the high pressure was adjusted to 15 MPa. The homogenization cycle was repeated once to obtain the novel composite flotation agent.

[0046] The following experimental data were obtained from the flotation experiment of the new composite flotation agent in the coal slurry water of Yangcheng Coal Mine.

[0047] Table 2 Experimental parameters and data

[0048]

[0049]

[0050] In the table, FF-1, FF-2 and FF-3 are flotation agents in this invention, with contents of 40 parts, 50 parts and 60 parts, respectively.

[0051] With increasing flotation reagent content, the collection capacity gradually increases, the yield of flotation clean coal increases, and the flotation indicators improve. The yield of flotation clean coal can reach over 80%, and the ash content of flotation clean coal is between 10-12%, while the ash content of tailings can reach over 70%. FF-2 and FF-3 show better overall flotation performance than diesel-based flotation reagents. Furthermore, this composite flotation reagent exhibits good stability, low viscosity, and requires less emulsifier, resulting in lower cost. Further increasing the flotation reagent content will continuously increase the cost of emulsifiers and reagents; therefore, the optimal flotation reagent content is 50-60 parts.

[0052] Example 3:

[0053] The composite flotation agent is prepared according to the following ratio: 60 parts flotation agent, 0.5 parts emulsifier, 1.0 part stabilizer, and 58.5 parts water. The flotation agent is prepared by mixing hydrophobically modified hydroxyethyl cellulose, No. 2 flotation oil, and tall oil in a weight ratio of (0.01-0.05):1:1.

[0054] At room temperature, sodium dodecyl sulfonate and water were first stirred in a high-speed mixer at 500 rpm for 30 minutes until the emulsifier was completely dissolved. Maintaining this stirring speed, the flotation agent was slowly added, and after stirring for 10 minutes, a uniformly dispersed emulsion was formed. Polyoxypropylene ethylene glycerol ether was then added, and stirring continued for another 10 minutes, resulting in a temporarily stable emulsion with a total mass of 500 g. The emulsion was immediately poured into a homogenizer. The low pressure of the homogenizer was first adjusted to 2 MPa, and then the high pressure was adjusted to 15 MPa. The homogenization cycle was repeated once to obtain the novel composite flotation agent.

[0055] The effects of different contents of hydrophobically modified hydroxyethyl cellulose on product parameters and flotation performance (flotation agent addition amount 800g / t) were compared, as shown in the table below. Among them, the ratio of No. 25 black reagent to No. 2 flotation oil to tall oil (by weight) was used for comparison group 1; the ratio of ethyl cellulose to No. 2 flotation oil to tall oil (by weight) was used for comparison group 2; and the ratio of hydrophobically modified hydroxyethyl cellulose to No. 2 flotation oil to tall oil was used for comparison group 1 to group 5.

[0056] Table 3 Experimental parameters and data

[0057]

[0058] Experiments revealed that when the weight ratio of hydrophobically modified hydroxyethyl cellulose (HHC): No. 2 flotation oil: tall oil was 0:1:1, 0.008:1:1, and 0.055:1:1, the clean coal yield was lower than the other three groups. When the proportion of HHC was low, the flotation agent had poor dispersion in the coal seam, weakening its ability to remove impurities and the stability of the foam. Conversely, when the proportion of HHC was high, the hydrophilic groups in HHC hindered the interaction between the flotation agent and the mineral surface, reducing the floatability of the effective minerals. Therefore, the addition of HHC can improve the collection performance of the flotation oil, and the ideal weight ratio of HHC to No. 2 flotation oil and tall oil is (0.01-0.05):1:1.

[0059] Example 4:

[0060] The composite flotation agent is prepared according to the following ratio: 60 parts flotation agent, 0.2-1.0 parts emulsifier, 38-38.8 parts water, and 1.0 part stabilizer. The flotation agent is prepared by hydrophobically modified hydroxyethyl cellulose, No. 2 flotation oil, and tall oil in a weight ratio of 0.05:1:1.

[0061] At room temperature, 0.8, 1, 2.5, 5, and 6 g of sodium dodecyl sulfonate and water were first mixed in proportion using a high-speed mixer at 500 rpm for 30 minutes until the emulsifier was completely dissolved. Maintaining this mixing speed, the flotation agent was slowly added, and after 10 minutes of mixing, a uniformly dispersed emulsion was formed. Polyoxypropylene ethylene glycerol ether was then added, and mixing continued for another 10 minutes, resulting in a temporarily stable emulsion with a total mass of 500 g. The emulsion was immediately poured into a homogenizer. The low pressure of the homogenizer was first adjusted to 2 MPa, and then the high pressure was adjusted to 15 MPa. The homogenization cycle was repeated once to obtain the novel composite flotation agent.

[0062] The effects of different emulsifier contents on product parameters and flotation performance (flotation agent addition amount 800g / t) are compared in the table below.

[0063] Table 4 Experimental parameters and data

[0064] Serial Number Emulsifier addition amount / g Dynamic viscosity / mPa·s (25℃) Stability (after standing for 7 days) Coal yield / % 1 0.8 18.33 Layering / 2 1 26.67 No layering 85.75 3 2.5 28.33 No layering 85.80 4 5 31.67 No layering 85.85 5 6 41.67 No layering 85.80

[0065] Experiments revealed that when the amount of emulsifier added was small, the product would separate into layers. As the amount added increased, the dynamic viscosity of the product gradually increased, which was not conducive to field use. Regarding the effect on clean coal yield, it can be seen that increasing the amount of emulsifier would increase the dispersion of the flotation agent and enhance the foaming effect. The clean coal yield would also increase with the increase of emulsifier. When a certain amount of emulsifier was added, the clean coal yield would decrease slightly. This is because excessive foaming would cause the tailings to be floated out. Therefore, the ideal amount of emulsifier added was determined to be 1-5g, which is equivalent to a mass fraction of 0.2-1.0 parts.

[0066] Example 5:

[0067] The composite flotation agent is prepared according to the following ratio: 60 parts flotation agent, 0.5 parts emulsifier, and 38.5-39.3 parts stabilizer. The flotation agent is prepared by hydrophobically modified hydroxyethyl cellulose, No. 2 flotation oil, and tall oil in a weight ratio of 0.05:1:1.

[0068] At room temperature, 1.5g of sodium dodecyl sulfonate, 1.0g of octylphenol polyoxyethylene ether, and water were first stirred in a high-speed mixer at 500 rpm for 30 minutes until the emulsifier was completely dissolved. Maintaining this stirring speed, the flotation agent was slowly added, and after stirring for 10 minutes, a uniformly dispersed emulsion was formed. Then, 0.8, 1, 2.5, 5, and 6g of stearic acid polyoxyethylene ether were added, and stirring continued for another 10 minutes to obtain a temporarily stable emulsion. The emulsion was immediately poured into a homogenizer. The low pressure of the homogenizer was first adjusted to 2MPa, and then the high pressure was adjusted to 15MPa. The homogenization cycle was repeated once to obtain the novel composite flotation agent.

[0069] The effects of different emulsifier contents on product parameters and flotation performance (flotation agent addition amount 800g / t) are compared in the table below.

[0070] Table 5 Experimental parameters and data

[0071] Serial Number stabilizer addition amount / g Dynamic viscosity / mPa·s (25℃) Stability (after standing for 7 days) Coal yield / % 1 0.8 38.33 No layering 85.65 2 1 28.33 No layering 85.75 3 2.5 26.67 No layering 85.80 4 5 26.67 No layering 85.85 5 6 25.00 Layering /

[0072] The addition of stabilizers plays a role in regulating the balance between emulsification and stratification to a certain extent. When foaming is excessive, stabilizers have a certain defoaming effect, and when stratification is severe, they can assist in emulsification. Experiments have shown that as the amount of stabilizer increases, the dynamic viscosity of the product gradually decreases. Stratification occurs when the stabilizer dosage is above 5g, while when the dosage is below 1g, the product viscosity is high and the clean coal yield is low. Therefore, the ideal stabilizer dosage is 1-5g, which translates to a mass fraction of 0.2-1.0 parts.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A novel composite flotation agent for coal mines, characterized in that, The composite flotation agent is composed of the following components in parts by weight: 50-60 parts of flotation reagent Emulsifier 0.2-1.0 parts Stabilizer 0.2-1.0 parts Water 38-59.6 parts The flotation agent comprises: hydrophobically modified hydroxyethyl cellulose, No. 2 flotation oil, and tall oil, with a weight ratio of (0.01-0.05):1:1 for each component. The preparation method of the novel composite flotation agent for coal mines includes the following steps: (1) At room temperature, mix the emulsifier with water and stir with a high-speed mixer at a speed of 500-700 rpm for 15-30 minutes until the emulsifier is completely dissolved to obtain a mixture; (2) Slowly add the flotation agent to the mixture and stir for 5-10 minutes to form a uniformly dispersed emulsion. Continue to add the stabilizer and stir for 10 minutes until the emulsion reaches a stable state to obtain a stable emulsion. (3) Pour the stable emulsion into a homogenizer, first adjust the low pressure of the homogenizer, then adjust the high pressure of the homogenizer, and homogenize and circulate once to obtain the novel composite flotation agent. The low pressure of the homogenizer is adjusted to 1-2 MPa, and the high pressure is adjusted to 10-15 MPa.

2. The novel composite flotation agent for coal mines according to claim 1, characterized in that, The emulsifier includes one or more of octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, and sodium lauryl ether sulfate.

3. The novel composite flotation agent for coal mines according to claim 1 or 2, characterized in that, The stabilizer includes one or more of polyethylene glycol stearate, polyoxyethylene stearate, and polyoxypropylene ethylene glycerol ether.

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