Environment-friendly foaming agent for improving hydrophobic coal dust collection rate and preparation method of environment-friendly foaming agent

Abstract

The invention belongs to the technical field of foaming agents for underground dust removal of coal mines, and discloses an environment-friendly foaming agent for improving the hydrophobic coal dust collection rate and a preparation method thereof. Aiming at the defects that the existing petroleum-based coal dust foaming agent is poor in biodegradability and insufficient in hydrophobic coal dust capturing and foam stabilizing capability, the invention provides the foaming agent. The foaming agent is prepared from an environment-friendly main surfactant, a cocamidopropyl betaine auxiliary surfactant, a silane coupling agent modified diatomite foam stabilizer, a biodegradation aid, a pH regulator and deionized water according to a ratio. The preparation method comprises the following steps: firstly preparing the modified foam stabilizer, and then performing surface activity premixing, composite system construction, pH regulation and post-treatment to obtain a finished product. The foaming agent has the advantages of excellent environmental protection property, strong hydrophobic coal dust capturing capability, good foam stability, simple and controllable preparation process and easily available raw materials, is suitable for large-scale coal mine underground production, and can effectively solve the problem of coal mine underground coal dust treatment.

Description

Technical Field

[0001] This invention relates to the field of coal mine safety, specifically to a type of environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust and its preparation method. Background Technology

[0002] Throughout the entire process of coal mining, tunneling, transportation, and processing, a large amount of coal dust is generated. Hydrophobic coal dust, due to its highly hydrophobic surface, is difficult to wet effectively with traditional water-based dust collectors, thus remaining suspended in the air for extended periods and easily spreading over large areas. This problem not only severely deteriorates the underground working environment but also pollutes surrounding farmland and residential areas near ventilation shafts, further threatening the health of workers and increasing the risk of pneumoconiosis. It also poses a significant safety hazard of dust explosions, placing dual pressure on both safe production and environmental governance in the coal industry.

[0003] Existing foaming agents for coal dust capture mostly use petroleum-based surfactants as the main agent. These foaming agents have significant technical shortcomings: firstly, their biodegradability is poor, and they easily remain in water and soil after use, causing secondary pollution, which is inconsistent with current stringent environmental protection policies; secondly, these foaming agents have insufficient wettability and adsorption capacity for hydrophobic coal dust, and the foam itself has poor stability, making it difficult to achieve efficient and long-term capture of hydrophobic coal dust. Although some improved foaming agents have improved foam stability by adding organic foam stabilizers, the introduction of organic additives further reduces the overall environmental performance, and at the same time, they do not fundamentally solve the problem of targeted capture of hydrophobic coal dust.

[0004] Addressing this industry pain point, the development of a foaming agent that simultaneously achieves high environmental friendliness, strong foam stability, and excellent hydrophobic coal dust capture capability has become an urgent technical need in the field of coal dust control in underground coal mines. Summary of the Invention

[0005] The present invention aims to solve the problems mentioned in the background art by providing an environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust and its preparation method.

[0006] The specific technical solution is as follows: An environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust, comprising, by mass percentage: 5%-15% environmentally friendly main surfactant, 2%-8% auxiliary surfactant, 1%-5% modified mineral foam stabilizer, 0.5%-3% biodegradable aid, 0.1%-1% pH adjuster, with the balance being deionized water.

[0007] This scheme defines the basic raw material components and corresponding mass ratios of environmentally friendly foaming agents. The core is the combination of environmentally friendly primary surfactants, secondary surfactants, modified mineral foam stabilizers, biodegradable additives, pH adjusters, and deionized water. From the scheme's perspective, the introduction of environmentally friendly primary surfactants ensures the environmentally friendly properties of the foaming agent from the source; secondary surfactants synergistically enhance wetting ability with the primary surfactant; modified mineral foam stabilizers balance foam stability and coal dust adsorption; biodegradable additives further enhance environmental friendliness; and pH adjusters maintain system stability. The technical effects are: achieving a basic balance between the environmental performance and dust removal performance of the foaming agent, avoiding secondary pollution from traditional petroleum-based raw materials, initially capturing and fixing hydrophobic coal dust, and ensuring the basic stability of the foam system.

[0008] The aforementioned environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust comprises, wherein the environmentally friendly main surfactant is selected from at least one of alkyl glycosides and sodium methyl ester sulfonate; the auxiliary surfactant is cocamidopropyl betaine; the modified mineral foam stabilizer is silane coupling agent modified diatomaceous earth; the biodegradable aid is selected from at least one of polyaspartic acid and polyglutamic acid; and the pH adjuster is selected from at least one of citric acid and sodium bicarbonate.

[0009] This scheme clearly defines the specific types of raw materials, such as selecting alkyl glycosides or sodium fatty acid methyl ester sulfonate as the main surfactant, cocamidopropyl betaine as the auxiliary surfactant, and silane coupling agent modified diatomaceous earth as the foam stabilizer. This combination of specific raw materials exhibits clear performance compatibility. The main surfactants, such as alkyl glycosides, possess excellent biodegradability and wettability; cocamidopropyl betaine enhances the foaming properties and compatibility of the system; silane coupling agent modified diatomaceous earth forms a hydrophobic-hydrophilic amphiphilic structure; polyaspartic acid-based additives improve overall degradation efficiency; and citric acid and other pH adjusters provide mild adjustment capabilities. The technical effects are: precise raw material selection strengthens the synergistic effect between components, further enhancing the biodegradability of the foaming agent to reduce environmental burden, endowing the foaming agent with targeted adsorption capabilities for hydrophobic coal dust, optimizing the foaming and stability performance of the foam system, and maintaining a mild pH level to ensure the performance stability of each component.

[0010] The aforementioned environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust includes diatomaceous earth, silane coupling agent, and ethanol aqueous solution as raw materials for preparing the silane coupling agent modified diatomaceous earth. The mass ratio of silane coupling agent to diatomaceous earth is 1:8-1:12, and the volume ratio of ethanol to water in the ethanol aqueous solution is 1:1-1:2.

[0011] This scheme specifies the raw material ratio for silane coupling agent-modified diatomaceous earth, clarifying the mass ratio of silane coupling agent to diatomaceous earth and the volume ratio of ethanol-water solution. From the perspective of ratio design, this range ensures uniform and appropriate grafting of the silane coupling agent onto the diatomaceous earth surface, preventing insufficient modification due to insufficient coupling agent dosage or surface agglomeration due to excessive dosage. The ethanol-water solution ratio provides a suitable medium environment for the reaction between the coupling agent and diatomaceous earth. The technical effects are: it enables the modified diatomaceous earth surface to form a stable amphoteric structure, enhancing its dispersibility in the foam system, improving its adsorption capacity for hydrophobic coal dust, and simultaneously forming a supporting structure within the foam film to enhance its rupture resistance.

[0012] The aforementioned environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust includes a pH adjuster used to adjust the pH of the foaming agent system to 6.5-7.5. This scheme limits the pH of the foaming agent system to the range of 6.5-7.5. This range is a mild range from neutral to weakly acidic / alkaline. Components in the foaming agent, such as surfactants and biodegradable additives, are prone to hydrolysis or structural damage in strong acidic / alkaline environments, leading to performance degradation. The technical benefits are: maintaining the acid-base balance of the foaming agent system, preventing functional components from failing due to unsuitable acidic / alkaline environments, ensuring the consistency of the foaming agent's performance during storage and use, and reducing the risk of corrosion to the equipment used.

[0013] This invention also provides a method for preparing an environmentally friendly foaming agent to improve the capture rate of hydrophobic coal dust, comprising the following steps: (1) Preparation of modified mineral foam stabilizer: After drying, crushing and sieving diatomaceous earth, add ethanol aqueous solution for ultrasonic dispersion, then add silane coupling agent and stir to react. After reaction, filter, wash, dry, grind and sieve to obtain modified mineral foam stabilizer. (2) Premixing of main and auxiliary surfactants: Take environmentally friendly main surfactants and auxiliary surfactants according to the ratio, add them to deionized water accounting for 40%-50% of the total deionized water mass and stir to obtain a premixed solution; (3) Construction of composite system: Add modified mineral foam stabilizer and biodegradable agent to premixed liquid, heat and stir to obtain mixed system; (4) pH adjustment and post-treatment: Add pH adjuster to the mixed system to adjust pH, add the remaining deionized water and stir, let stand to defoam, and the environmentally friendly foaming agent is obtained.

[0014] This scheme defines the overall preparation process of the foaming agent, divided into four core steps: preparation of modified mineral foam stabilizers, premixing of primary and secondary surfactants, construction of the composite system, pH adjustment, and post-treatment. The step-by-step preparation design avoids problems such as agglomeration and reaction interference that occur when components are directly mixed. Modifying the foam stabilizer before subsequent compounding ensures the functional integrity of the stabilizer, while premixing the surfactants provides a stable foundation for the subsequent composite system. The technical advantages are: the orderly preparation steps ensure the full preservation of the performance of each functional component, achieving uniform fusion and synergistic effects among the components; the overall process requires no special equipment, facilitating mass production in coal mines; and it also guarantees the uniformity of the finished foaming agent's performance.

[0015] The above-mentioned method for preparing an environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust includes the following steps: In step (1), the diatomaceous earth is dried at a temperature of 105-110℃ for 2-3 hours and then pulverized and passed through a 200-300 mesh sieve; the ultrasonic dispersion time is 15-20 minutes; after the silane coupling agent is added, the mixture is stirred at 300-400 r / min at 50-70℃ for 2-4 hours; the filter cake is washed with deionized water 3-5 times, dried at 100-105℃ for 4-6 hours, ground, and then passed through a 300 mesh sieve.

[0016] This scheme defines specific process parameters for the preparation of modified mineral foam stabilizers, including the drying temperature and time of diatomaceous earth, sieve mesh size, ultrasonic dispersion time, reaction temperature, and rotation speed. These parameters ensure that the diatomaceous earth is thoroughly dried to remove impurities and moisture, that fine sieving increases its specific surface area, and that suitable ultrasonic and stirring conditions ensure a complete and uniform reaction between the silane coupling agent and the diatomaceous earth. The technical effects are: the prepared modified mineral foam stabilizer possesses a stable physical structure and surface properties, fully utilizing its dual functions of adsorbing coal dust and stabilizing foam, while ensuring the fineness and dispersibility of the stabilizer powder, preventing agglomeration in the foam system.

[0017] The above-mentioned method for preparing environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust includes step (2) where the stirring temperature is 30-40℃, the stirring speed is 200-300r / min, and the stirring time is 15-30min.

[0018] This scheme specifies the temperature, stirring speed, and time parameters for premixing the primary and secondary surfactants. A temperature of 30-40℃ ensures rapid dissolution of the surfactants without structural damage due to excessive temperature. Appropriate stirring speed and duration allow for thorough mixing of the primary and secondary surfactants to form a homogeneous system. The technical effects are: promoting the formation of a synergistic wetting and foaming system between the primary and secondary surfactants, improving overall foaming capacity and wetting effect on coal dust; and the uniformity of the premixed solution lays a stable foundation for the subsequent addition of other components.

[0019] The above-mentioned method for preparing environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust includes step (3) where the temperature is raised to 45-55℃, the stirring speed is 400-500r / min, and the stirring time is 30-60min.

[0020] This scheme limits the temperature and rotation speed parameters for constructing the composite system. A temperature of 45-55℃ improves the dissolution and dispersion efficiency of the modified mineral foam stabilizer and biodegradable additive in the premix, while a rotation speed of 400-500 r / min ensures uniform dispersion of each component. The technical effects are: it allows the modified mineral foam stabilizer, biodegradable additive, and main and auxiliary surfactant system to fully integrate, strengthening the synergistic effect between components, further improving the environmental performance, coal dust adsorption performance, and foam stability of the foaming agent, and avoiding problems such as excessively high local component concentrations or uneven distribution.

[0021] The above-mentioned method for preparing an environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust includes step (4) where the pH of the system is adjusted to 6.5-7.5; after adding deionized water, the system is stirred at 200 r / min for 10-20 min at 25-30℃.

[0022] This scheme defines the target pH range for adjustment and the stirring conditions after water addition. Adjusting the pH to 6.5-7.5 maintains a mild and stable system, while low-temperature, low-speed stirring after water addition ensures a uniform concentration distribution. The technical benefits are: ensuring the overall stability of the foaming agent system, preventing performance issues caused by localized concentration differences, maintaining the activity of each functional component, and ensuring the foaming agent can stably perform its dust removal and environmental protection functions in subsequent use.

[0023] The above-mentioned method for preparing an environmentally friendly foaming agent to improve the capture rate of hydrophobic coal dust includes a step (4) in which the settling and defoaming time is 30-60 minutes. This method limits the settling and defoaming time range. During the preparation process, excess bubbles will be generated due to stirring. These bubbles will affect the uniformity of the finished foaming agent. A settling time of 30-60 minutes allows the excess bubbles to escape naturally. The technical effect is: to remove the ineffective bubbles generated during the preparation process, to ensure the uniformity of the finished foaming agent system, to avoid residual bubbles interfering with the foam generation and stabilization effect during subsequent use, and to improve the reliability of the foaming agent in practical applications.

[0024] The present invention has the following beneficial effects: 1. Outstanding environmental performance: This solution controls the environmental properties from the source of raw materials. The main and auxiliary surfactants and biodegradable additives are all biodegradable and contain no petroleum-based harmful components. Furthermore, the biodegradable additives can enhance the degradation efficiency in the natural environment. Therefore, the foaming agent will not cause secondary pollution after use and can meet the industry's environmental emission standards, making it suitable for application scenarios with stringent environmental requirements such as green mines.

[0025] 2. Excellent hydrophobic coal dust capture ability: The hydrophobic-hydrophilic bipolar structure of the modified mineral foam stabilizer can achieve targeted adsorption of hydrophobic coal dust, while the composite surfactant can effectively wet the coal dust surface. The two form a synergistic effect, which greatly improves the capture effect of hydrophobic coal dust and can solve the industry problem of insufficient capture of hydrophobic coal dust by traditional foaming agents.

[0026] 3. Good foam stability: The layered structure of modified diatomite forms a support network within the foam membrane, which enhances the toughness and rupture resistance of the foam membrane, prolongs the foam's lifespan, and achieves long-term capture of coal dust. It eliminates the need for frequent replenishment of foaming agent, reducing the consumption of chemicals and the frequency of operations on site.

[0027] 4. Strong adaptability to underground coal mines: The preparation process of this solution is clear and the parameters are controllable. No special equipment is required in each step. All raw materials used are common and readily available, and the production cost is controllable. At the same time, the process can achieve large-scale batch production, and the finished product has uniform performance, which can meet the large-scale application needs of coal dust control in underground coal mines. Attached Figure Description

[0028] Figure 1 A flowchart illustrating a method for preparing an environmentally friendly foaming agent to improve the capture rate of hydrophobic coal dust, as provided in an embodiment of the present invention. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the scope of this application. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0031] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0032] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] Reference Figure 1 The following three embodiments are provided in this specific implementation.

[0034] Example 1 I. Technical Solution

[0035] 1. Raw material composition and proportion (by mass percentage): 10% of environmentally friendly main surfactant alkyl glycoside, 5% of auxiliary surfactant cocamidopropyl betaine, 3% of modified mineral foam stabilizer silane coupling agent modified diatomaceous earth, 1.5% of biodegradable aid polyaspartic acid, 0.5% of pH adjuster citric acid, and the balance is 80% deionized water.

[0036] The raw material ratio for preparing silane coupling agent modified diatomaceous earth is as follows: the mass ratio of silane coupling agent to diatomaceous earth is 1:10, and the volume ratio of ethanol to water in the ethanol aqueous solution is 1:1.

[0037] 2. Preparation process 2.1 Preparation of modified mineral foam stabilizer: Diatomaceous earth was dried at 105℃ for 2h, pulverized and passed through a 200-mesh sieve. 10g of the sieved diatomaceous earth was added to 50mL of the above-mentioned ethanol aqueous solution and ultrasonically dispersed for 15min. 1g of silane coupling agent KH550 was added and stirred at 350r / min at 60℃ for 3h. After the reaction, the mixture was filtered, the filter cake was washed 4 times with deionized water, dried at 100℃ for 5h, and ground through a 300-mesh sieve to obtain the modified mineral foam stabilizer.

[0038] 2.2 Premixing of main and auxiliary surfactants: Take the alkyl glycoside and cocamidopropyl betaine in the above ratio, add 32g of deionized water (accounting for 40% of the total deionized water mass), and stir at 250r / min for 20min at 35℃ to obtain the premixed solution.

[0039] 2.3 Construction of composite system: Modified mineral foam stabilizer and polyaspartic acid were added to the premixed liquid, the temperature was raised to 50℃, and the mixture was stirred at 450r / min for 45min to obtain the mixed system.

[0040] 2.4 pH adjustment and post-treatment: Add citric acid to the mixed system to adjust the pH to 7.0, add 48g of remaining deionized water, stir at 200r / min for 15min at 28℃, let stand for defoaming for 45min to obtain the finished foaming agent.

[0041] II. Working Principle 1. Function of modified mineral foam stabilizer: Silane coupling agent is grafted onto the surface of diatomaceous earth to form a hydrophobic-hydrophilic bipolar structure. The hydrophobic end can bind to the surface of hydrophobic coal dust to achieve targeted adsorption, while the hydrophilic end can be anchored in the foam film. At the same time, the layered structure of diatomaceous earth forms a support network in the foam film, delaying foam rupture.

[0042] 2. Synergistic effect of surfactants: Alkyl glycosides and cocamidopropyl betaine form mixed micelles, which significantly reduce the surface tension of the aqueous solution and improve the foaming ability. At the same time, cocamidopropyl betaine can enhance the compatibility of the system and strengthen the wetting and encapsulation effect on coal dust.

[0043] 3. Environmental protection and system stabilization effects: Polyaspartic acid can promote the microbial degradation of foaming agents in the natural environment and avoid secondary pollution; citric acid adjusts the pH of the system to the neutral range, ensuring the structural stability of each component and preventing its hydrolysis and failure.

[0044] III. Technical Effects 1. Because it uses alkyl glycosides as the environmentally friendly main surfactant and is combined with polyaspartic acid biodegradable additive, the foaming agent has excellent biodegradability and leaves no environmental residue after use.

[0045] 2. The amphoteric structure of the modified mineral foam stabilizer enables targeted adsorption of hydrophobic coal dust. Combined with the wetting and encapsulating effects of the main and auxiliary surfactants, it significantly improves the capture effect of hydrophobic coal dust.

[0046] 3. The supporting effect of the layered structure of diatomaceous earth and the foaming ability of surfactants work synergistically to give the foam good stability, achieve long-term dust removal, and avoid frequent replenishment of foaming agent.

[0047] 4. The preparation process parameters are all within the scope of the claims, the components are mixed evenly, the finished product has uniform performance, and it can meet the needs of mass production in underground coal mines.

[0048] IV. Experimental Data Biodegradation rate: 93%; Foam half-life: 125 min; Hydrophobic coal dust capture rate: 89%; The pH value of the system was 7.0 (no significant fluctuation after standing for 30 days).

[0049] Example 2

[0050] I. Technical Solution

[0051] 1. Raw material composition and proportion (by mass percentage): 8% of the environmentally friendly main surfactant sodium fatty acid methyl ester sulfonate, 3% of the auxiliary surfactant cocamidopropyl betaine, 2% of the modified mineral foam stabilizer silane coupling agent modified diatomaceous earth, 1% of the biodegradable aid polyglutamic acid, 0.3% of the pH adjuster sodium bicarbonate, and the balance is 85.7% deionized water.

[0052] The raw material ratio for preparing silane coupling agent modified diatomaceous earth is as follows: the mass ratio of silane coupling agent to diatomaceous earth is 1:12, and the volume ratio of ethanol to water in the ethanol aqueous solution is 1:2.

[0053] 2. Preparation process 2.1 Preparation of modified mineral foam stabilizer: Diatomaceous earth was dried at 110℃ for 3h, pulverized and passed through a 300-mesh sieve. 12g of the sieved diatomaceous earth was added to 60mL of the above-mentioned ethanol aqueous solution and ultrasonically dispersed for 20min. 1g of silane coupling agent KH570 was added and stirred at 300r / min at 55℃ for 4h. After the reaction, the mixture was filtered, the filter cake was washed 5 times with deionized water, dried at 105℃ for 4h, and ground through a 300-mesh sieve to obtain the modified mineral foam stabilizer.

[0054] 2.2 Premixing of main and auxiliary surfactants: Take the sodium fatty acid methyl ester sulfonate and cocamidopropyl betaine in the above ratio, add 34.28g of deionized water (accounting for 40% of the total deionized water mass), and stir at 200r / min for 30min at 30℃ to obtain the premixed solution.

[0055] 2.3 Construction of composite system: Modified mineral foam stabilizer and polyglutamic acid were added to the premixed liquid, the temperature was raised to 45℃, and the mixture was stirred at 400r / min for 60min to obtain the mixed system.

[0056] 2.4 pH adjustment and post-treatment: Add sodium bicarbonate to the mixture to adjust the pH to 6.8, add 51.42g of remaining deionized water, stir at 200r / min for 20min at 25℃, let stand for defoaming for 30min to obtain the finished foaming agent.

[0057] II. Working Principle Environmental protection and wetting effect of the main surfactant: Sodium fatty acid methyl ester sulfonate is a biodegradable surfactant. Its hydrophilic group can combine with water molecules, and its hydrophobic group can penetrate to the surface of hydrophobic coal dust, destroy the hydrophobic interface of coal dust particles, and achieve preliminary wetting.

[0058] The dual function of modified foam stabilizers: Diatomaceous earth modified with silane coupling agent KH570 has surface active groups that can enhance the bonding force with the foam film and improve the foam toughness; at the same time, its porous structure can adsorb coal dust particles and prevent dust particles from escaping.

[0059] Mild system protection: Sodium bicarbonate is a weak alkaline regulator that can stabilize the pH of the system in the weak neutral range, which avoids the corrosion of equipment by strong acids and prevents the hydrolysis of surfactants caused by strong alkalis. At the same time, polyglutamic acid can further improve the biodegradation rate of foaming agent.

[0060] III. Technical Effects 1. The combination of sodium fatty acid methyl ester sulfonate and polyglutamic acid gives the foaming agent outstanding biodegradability, with no secondary pollution to soil and water, making it suitable for coal mine operation scenarios with stringent environmental protection requirements.

[0061] 2. Low-dose modified mineral foam stabilizers can achieve the dual effects of foam stabilization and coal dust adsorption, reducing raw material costs while ensuring dust removal efficiency.

[0062] 3. The use of a weakly alkaline pH adjuster and foaming agent results in extremely low corrosiveness to dust removal equipment, extending equipment lifespan. Furthermore, the system exhibits strong storage stability and shows no stratification failure even after long-term storage.

[0063] 4. The low temperature and low speed conditions of the preparation process can reduce production energy consumption and are suitable for the production conditions of small and medium-sized enterprises.

[0064] IV. Experimental Data Biodegradation rate: 92%; Foam half-life: 122 min; Hydrophobic coal dust capture rate: 88%; Corrosion rate of equipment: 0.002 mm / a (for carbon steel).

[0065] Example 3

[0066] I. Technical Solution

[0067] 1. Raw material composition and proportion (by mass percentage): 5% environmentally friendly main surfactant alkyl glycoside + 5% sodium fatty acid methyl ester sulfonate (total 10%), 8% auxiliary surfactant cocamidopropyl betaine, 5% modified mineral foam stabilizer silane coupling agent modified diatomaceous earth, 2% biodegradable aid polyaspartic acid + 1% polyglutamic acid (total 3%), 1% pH adjuster citric acid, and the balance is 73% deionized water.

[0068] The raw material ratio for preparing silane coupling agent modified diatomaceous earth is as follows: the mass ratio of silane coupling agent to diatomaceous earth is 1:8, and the volume ratio of ethanol to water in the ethanol aqueous solution is 1:1.5.

[0069] 2. Preparation process 2.1 Preparation of modified mineral foam stabilizer: Diatomaceous earth was dried at 108℃ for 2.5h, pulverized and passed through a 250-mesh sieve. 10g of the sieved diatomaceous earth was added to 50mL of the above-mentioned ethanol aqueous solution and ultrasonically dispersed for 18min. 1.2g of silane coupling agent KH560 was added and stirred at 70℃ and 400r / min for 2h. After the reaction, the mixture was filtered, the filter cake was washed 3 times with deionized water, dried at 102℃ for 6h, and ground through a 300-mesh sieve to obtain the modified mineral foam stabilizer.

[0070] 2.2 Premixing of main and auxiliary surfactants: Take the alkyl glycoside, sodium fatty acid methyl ester sulfonate and cocamidopropyl betaine in the above ratio, add 29.2g of deionized water (accounting for 40% of the total deionized water mass), and stir at 300r / min for 15min at 40℃ to obtain the premixed solution.

[0071] 2.3 Construction of composite system: Modified mineral foam stabilizer, polyaspartic acid and polyglutamic acid were added to the premixed liquid, the temperature was raised to 55℃, and the mixture was stirred at 500 r / min for 30 min to obtain the mixed system.

[0072] 2.4 pH adjustment and post-treatment: Add citric acid to the mixture to adjust the pH to 7.2, add 43.8g of remaining deionized water, stir at 200r / min for 10min at 30℃, let stand for 60min to defoam, and obtain the finished foaming agent.

[0073] II. Working Principle Synergistic effect of compound surfactants: The high foaming properties of alkyl glycosides and the strong wetting properties of sodium fatty acid methyl ester sulfonate complement each other. When combined with a high dose of cocamidopropyl betaine, a dense and tough foam layer can be formed to achieve all-round encapsulation of coal dust.

[0074] The enhancing effect of compound biodegradable additives: The broad-spectrum degradability of polyaspartic acid combined with the rapid degradability of polyglutamic acid can ensure the degradation efficiency of foaming agents under different environmental conditions; at the same time, the two can synergistically disperse and modify diatomaceous earth, preventing its aggregation.

[0075] The powerful effect of high-dose modified foam stabilizer: The high proportion of silane coupling agent modified diatomaceous earth can form a dense support network in the foam film. At the same time, its large number of adsorption sites can achieve batch capture of hydrophobic coal dust, improving the overall dust removal efficiency.

[0076] III. Technical Effects 1. The dual compound system of main surfactant and biodegradable additive enables the foaming agent to have excellent foaming ability, wetting ability and biodegradability at the same time, and outstanding comprehensive environmental protection and dust removal performance.

[0077] 2. The addition of high-dose modified mineral foam stabilizer significantly improves foam stability and coal dust adsorption capacity, making it suitable for operation scenarios with high coal dust concentration and achieving efficient dust removal in one go.

[0078] 3. Citric acid stabilizes the pH of the system in the neutral to slightly alkaline range, ensuring the compatibility of the compound components. The finished product has no stratification or precipitation and has a long storage period.

[0079] 4. The high temperature and high speed stage of the preparation process can promote the full integration of the compound components, resulting in strong consistency of finished product performance and making it suitable for large-scale standardized production.

[0080] IV. Experimental Data Biodegradation rate: 95%; Foam half-life: 130 min; Hydrophobic coal dust capture rate: 91%; Storage stability: No stratification or sedimentation was observed after 6 months of standing.

[0081] In summary, the working principle of the environmentally friendly foaming agent and its preparation method for improving the capture rate of hydrophobic coal dust provided in this specific embodiment is as follows: 1. The dual-action principle of modified mineral foam stabilizers: First, diatomaceous earth is modified with silane coupling agents through a specific process, so that the surface of diatomaceous earth forms a hydrophobic-hydrophilic bipolar structure. The hydrophobic end can form an affinity with the hydrophobic coal dust surface, realizing the targeted adsorption of coal dust; the hydrophilic end can anchor inside the foam film. At the same time, the layered structure of diatomaceous earth itself can build a support network in the foam film, delaying foam rupture, thus achieving both coal dust adsorption and ensuring long-term foam stability.

[0082] 2. Synergistic wetting and foaming principle of surfactants: When environmentally friendly main surfactant and auxiliary surfactant cocamidopropyl betaine are compounded, they can form mixed micelles, which can significantly reduce the surface tension of the aqueous solution. This can not only improve the overall foaming ability and form a dense foam layer, but also enhance the wetting and encapsulation effect on hydrophobic coal dust, destroy the hydrophobic interface of coal dust particles, and make coal dust easier to be adhered and captured by foam.

[0083] 3. Environmental performance guarantee principle: The main and auxiliary surfactants are all biodegradable and free of petroleum-based harmful substances. At the same time, they are combined with polyaspartic acid or polyglutamic acid biodegradable additives, which can further promote the microbial degradation of foaming agents in the natural environment. The overall environmental performance is guaranteed from both the selection of raw materials and the combination of functional additives, avoiding environmental residues after use.

[0084] 4. System stability assurance principle: The pH of the foaming agent system is adjusted to a mild range of 6.5-7.5 by using citric acid or sodium bicarbonate pH adjusters. This avoids problems such as surfactant hydrolysis and damage to the modified diatomaceous earth structure caused by strong acid and alkaline environments, ensuring the structural and performance stability of each functional component. At the same time, the orderly preparation process can achieve uniform mixing of each component, ensuring the uniform performance of the finished foaming agent.

[0085] The specific technical effects are as follows: 1. Outstanding environmental performance: This solution controls the environmental properties from the source of raw materials. The main and auxiliary surfactants and biodegradable additives are all biodegradable and contain no petroleum-based harmful components. Furthermore, the biodegradable additives can enhance the degradation efficiency in the natural environment. Therefore, the foaming agent will not cause secondary pollution after use and can meet the industry's environmental emission standards, making it suitable for application scenarios with stringent environmental requirements such as green mines.

[0086] 2. Excellent hydrophobic coal dust capture ability: The hydrophobic-hydrophilic bipolar structure of the modified mineral foam stabilizer can achieve targeted adsorption of hydrophobic coal dust, while the composite surfactant can effectively wet the coal dust surface. The two form a synergistic effect, which greatly improves the capture effect of hydrophobic coal dust and can solve the industry problem of insufficient capture of hydrophobic coal dust by traditional foaming agents.

[0087] 3. Good foam stability: The layered structure of modified diatomite forms a support network within the foam membrane, which enhances the toughness and rupture resistance of the foam membrane, prolongs the foam's lifespan, and achieves long-term capture of coal dust. It eliminates the need for frequent replenishment of foaming agent, reducing the consumption of chemicals and the frequency of operations on site.

[0088] 4. Strong adaptability to underground coal mines: The preparation process of this solution is clear and the parameters are controllable. No special equipment is required in each step. All raw materials used are common and readily available, and the production cost is controllable. At the same time, the process can achieve large-scale batch production, and the finished product has uniform performance, which can meet the large-scale application needs of coal dust control in underground coal mines.

[0089] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. An environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust, characterized in that, By mass percentage, its raw material components include: 5%-15% environmentally friendly main surfactant, 2%-8% auxiliary surfactant, 1%-5% modified mineral foam stabilizer, 0.5%-3% biodegradable aid, 0.1%-1% pH adjuster, and the balance being deionized water.

2. The environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust according to claim 1, characterized in that, The environmentally friendly main surfactant is selected from at least one of alkyl glycosides and sodium fatty acid methyl ester sulfonate; the auxiliary surfactant is cocamidopropyl betaine; and the modified mineral foam stabilizer is silane coupling agent modified diatomaceous earth. The biodegradable agent is selected from at least one of polyaspartic acid and polyglutamic acid; the pH adjuster is selected from at least one of citric acid and sodium bicarbonate.

3. The environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust according to claim 2, characterized in that, The raw materials for preparing the silane coupling agent modified diatomaceous earth include diatomaceous earth, silane coupling agent and ethanol aqueous solution, wherein the mass ratio of silane coupling agent to diatomaceous earth is 1:8-1:12, and the volume ratio of ethanol to water in the ethanol aqueous solution is 1:1-1:

2.

4. The environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust according to claim 1, characterized in that, The pH adjuster is used to adjust the pH of the foaming agent system to 6.5-7.

5.

5. A method for preparing an environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust as described in any one of claims 1-4, characterized in that, Includes the following steps: (1) Preparation of modified mineral foam stabilizer: After drying, crushing and sieving diatomaceous earth, add ethanol aqueous solution for ultrasonic dispersion, then add silane coupling agent and stir to react. After reaction, filter, wash, dry, grind and sieve to obtain modified mineral foam stabilizer. (2) Premixing of main and auxiliary surfactants: Take environmentally friendly main surfactants and auxiliary surfactants according to the ratio, add them to deionized water accounting for 40%-50% of the total deionized water mass and stir to obtain a premixed solution; (3) Construction of composite system: Add modified mineral foam stabilizer and biodegradable agent to premixed liquid, heat and stir to obtain mixed system; (4) pH adjustment and post-treatment: Add pH adjuster to the mixed system to adjust pH, add the remaining deionized water and stir, let stand to defoam, and the environmentally friendly foaming agent is obtained.

6. The method for preparing the environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust according to claim 5, characterized in that, In step (1), the diatomaceous earth is dried at 105-110℃ for 2-3 hours and then pulverized and passed through a 200-300 mesh sieve. The ultrasonic dispersion time is 15-20 minutes. After the silane coupling agent is added, the mixture is stirred at 300-400 r / min at 50-70℃ for 2-4 hours. The filter cake is washed with deionized water 3-5 times, dried at 100-105℃ for 4-6 hours, ground, and then passed through a 300 mesh sieve.

7. The method for preparing the environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust according to claim 5, characterized in that, In step (2), the stirring temperature is 30-40℃, the stirring speed is 200-300r / min, and the stirring time is 15-30min.

8. The method for preparing the environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust according to claim 5, characterized in that, In step (3), the temperature is raised to 45-55℃, the stirring speed is 400-500r / min, and the stirring time is 30-60min.

9. The method for preparing the environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust according to claim 5, characterized in that, In step (4), adjust the pH of the system to 6.5-7.5; after adding deionized water, stir at 200 r / min for 10-20 min at 25-30℃.

10. The method for preparing the environmentally friendly foaming agent for improving the capture rate of hydrophobic coal dust according to claim 5, characterized in that, In step (4), the standing defoaming time is 30-60 minutes.

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