Environment-friendly efficient dust suppressant based on block copolymer as well as preparation method and use method of environment-friendly efficient dust suppressant

Abstract

The invention discloses an environment-friendly high-efficiency dust suppressant based on a block copolymer as well as a preparation method and a use method thereof. The dust suppressant is prepared from the following raw materials in percentage by mass: 10 to 15 percent of PMAA-PEGME, 3 to 5 percent of an anti-freezing agent, 2 to 5 percent of natural vegetable gum, 5 to 10 percent of a mineral adsorbent, 0.5 to 1 percent of a surfactant, 0.1 to 0.3 percent of a preservative and the balance of deionized water. The method comprises the following steps: firstly measuring a contact angle theta of dust, then determining the adding proportion of the dust suppressant and water, then mixing and diluting the dust suppressant and water, adding the mixture into a spraying device, and spraying the mixture to a dust production source. The preparation method is simple, and the obtained dust suppressant can significantly improve the dust capturing and condensing effects, more rapidly form a protective film on the surface of dust, inhibit the diffusion and suspension of dust, and greatly improve the dust suppression effect; in addition, according to the using method, the adding proportion of the dust suppressant can be determined according to the contact angle theta of dust, and therefore the better dust suppression effect is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of dust prevention and control, and specifically relates to an environmentally friendly and efficient dust suppressant based on a block copolymer, and a preparation method and a use method thereof. Background Art

[0002] In recent years, a large amount of dust has been generated in coal crushing, screening, transportation and storage in coal preparation plants. Coal dust has brought many negative impacts on the occupational health of operators, plant environment, equipment maintenance and production safety, and has posed a serious threat to the safety of employees and property.

[0003] Studies have shown that in order to effectively reduce the spread and harm of dust, the application of chemical dust suppressants is considered to be an effective means of dust control in coal preparation plants. Various dust suppressants have been developed at home and abroad, and widely used ones include surfactants, natural polymers, inorganic salts, and acrylic polymers. Although these dust suppressants play an important role in suppressing dust spread and improving the safety of the working environment, they have also exposed many problems in actual application: for example, although surfactant dust suppressants can significantly reduce the hydrophobicity of dust, the dust suppression time is short and the cost of frequent use is high; although natural polymer dust suppressants are environmentally friendly, they are easily affected by temperature, and their high viscosity makes spraying difficult; inorganic salt dust suppressants are cheap, but they are highly corrosive and easily damage equipment, and the dust suppression layer is easily washed away by rain; acrylic polymer dust suppressants have good dust suppression effects, but their high cost limits their promotion and application in large-scale industrial production.

[0004] In summary, the existing dust suppression materials in coal preparation plants still have deficiencies in cost, performance, environmental adaptability, etc. In order to effectively control dust pollution in coal preparation plants and reduce the impact on the environment and equipment, it is urgent to develop new dust suppression materials, break the technical limitations of traditional dust suppressants, and find more efficient, environmentally friendly, and adaptable dust suppression materials and technologies to meet the actual needs of the complex production environment of coal preparation plants. Summary of the invention

[0005] The purpose of the present invention is to provide an environmentally friendly and efficient dust suppressant based on a block copolymer, and a preparation method and a use method thereof. The preparation method is simple, and the prepared dust suppressant can significantly improve the capture and agglomeration effect of dust, more quickly form a protective film on the surface of dust, inhibit the diffusion and suspension of dust, and greatly improve the dust suppression effect; in addition, the use method can determine the addition ratio of the dust suppressant according to the contact angle θ of the dust, thereby achieving a better dust suppression effect.

[0006] To achieve the above-mentioned purpose, the present invention provides an environmentally friendly and efficient dust suppressant based on block copolymers, wherein the dust suppressant is composed of the following raw materials in percentage by mass: PMAA-PEGME 10%-15%, antifreeze agent 3%-5%, natural plant gum 2%-5%, mineral adsorbent 5%-10%, surfactant 0.5%-1%, preservative 0.1%-0.3%, and the remaining component is deionized water.

[0007] Furthermore, the preparation process of PMAA-PEGME is as follows: using polyethylene glycol methyl ether as a hydrophilic segment precursor, methacrylic acid as a lipophilic segment precursor, azobisisobutyronitrile as an initiator, methacrylic anhydride or acryloyl chloride as an activator, thioglycolic acid as a chain transfer agent, and toluene as an anhydrous solvent, PMAA-PEGME is prepared by an active free radical polymerization method.

[0008] Furthermore, the specific preparation process of the PMAA-PEGME is as follows: using methacrylic anhydride as an activator, activating the terminal hydroxyl group of polyethylene glycol methyl ether at 80-90°C for 6-8h, converting the terminal hydroxyl group of polyethylene glycol methyl ether into an acrylate group, then adding methacrylic acid, azobisisobutyronitrile, thioglycolic acid and toluene to mix, then carrying out a block copolymerization reaction at 60-80°C for 8-10h under nitrogen protection, removing the solvent by rotary evaporation or reduced pressure distillation after natural cooling, dissolving the reaction product in methanol or ether, and then dropping a large amount of icy ether to precipitate and obtain PMAA-PEGME.

[0009] Preferably, based on the mass of polyethylene glycol methyl ether, the amount of methacrylic anhydride is 10%-15% of the base mass, the amount of methacrylic acid is 20%-30% of the base mass, the amount of azobisisobutyronitrile is 0.5%-1% of the base mass, the amount of thioglycolic acid is 1%-2% of the base mass, and the amount of toluene is 10-15 times of the base mass.

[0010] Furthermore, the preparation process of the antifreeze agent is: using urea, ethylene glycol and propylene glycol as raw materials, and pressurizing and heating in an aqueous solution to produce a condensation reaction to prepare the antifreeze agent.

[0011] Furthermore, the specific preparation process of the antifreeze agent is: premixing ethylene glycol, propylene glycol and water for 5-8 minutes, then adding urea to dissolve to obtain a reaction solution; transferring the reaction solution to a pressure-resistant reactor, heating to 120-150° C., controlling the pressure at 0.5-1 MPa, reacting for 1-2 hours to promote the condensation reaction of ethylene glycol, propylene glycol and urea, and after the reaction is completed, slowly cooling and reducing the pressure to room temperature and normal pressure, filtering the solution and removing unreacted impurities to obtain the antifreeze agent.

[0012] Preferably, the molar ratio of urea, ethylene glycol and propylene glycol is 1:(1.5-2.5):(0.5-1.5), the mass fraction of urea in the reaction solution is 15%-25%, the mass fraction of ethylene glycol in the reaction solution is 35%-45%, and the mass fraction of propylene glycol in the reaction solution is 10%-25%.

[0013] Preferably, the natural plant gum is xanthan gum or guar gum; the mineral adsorbent is bentonite or expanded diatomaceous earth; the preservative is sodium benzoate or potassium sorbate; the surfactant is an anionic surfactant, and the anionic surfactant is sodium dodecylbenzene sulfonate or sodium alkyl sulfate.

[0014] To achieve the above object, the present invention also provides a method for preparing the above environmentally friendly and efficient dust suppressant based on the block copolymer, comprising the following steps:

[0015] S1. Weigh each component by mass percentage; put deionized water into a heating device, control the temperature at 40-50°C, then add PMAA-PEGME to the preheated deionized water, stir at a speed of 300-500rpm, stir for 30-40min, and stir evenly until completely dissolved;

[0016] S2, adding natural plant gum to the solution obtained in step S1, stirring at a speed of 150-200 rpm, stirring for 20-30 min, stirring until a viscous and uniform colloid is formed; then adding a mineral adsorbent to the colloid, stirring at a speed of 150-200 rpm, stirring for 10-20 min, stirring until the adsorbent is evenly distributed in the colloid;

[0017] S3, adding antifreeze to the sample obtained in step S2, stirring at a speed of 60-100 rpm, stirring for 5-10 min, stirring until the antifreeze is fully dissolved, and then adding surfactant, stirring at a speed of 100-150 rpm, stirring for 20-30 min;

[0018] S4, adding a preservative to the sample obtained in step S3, stirring at a speed of 60-100 rpm for 10-20 min, stirring until the preservative is completely dissolved, and then adjusting the pH value to 5.5-7.0 with a sodium hydroxide solution;

[0019] S5. Cool the sample obtained in step S4 to 25° C. at room temperature, and stir the sample during the cooling process to mix it evenly, thereby obtaining an environmentally friendly and efficient dust suppressant based on the block copolymer.

[0020] To achieve the above object, the present invention also provides a method for using the above environmentally friendly and efficient dust suppressant based on the block copolymer, comprising the following steps:

[0021] (1) Use a dust sampler to collect dust at the work site;

[0022] (2) using a contact angle tester to measure the contact angle θ of the dust sample, and using the measured contact angle θ to characterize the hydrophobicity of the dust;

[0023] (3) According to the contact angle θ of the dust sample, determine the addition ratio of dust suppressant and water. The specific addition ratio is as follows:

[0024] When the contact angle is 0<θ≤40°, the dust suppressant addition ratio ω is controlled between 1% and 3%, which can be calculated using the formula ω=2%+(1-cosθ)×1%;

[0025] When the contact angle is 40<θ≤80°, the dust suppressant addition ratio ω is controlled between 2% and 5%, which can be calculated using the formula ω=3%+(1-cosθ)×2%;

[0026] When the contact angle is 80<θ≤120°, the dust suppressant addition ratio ω is controlled between 3% and 8%, which can be calculated using the formula ω=5%+(1-cosθ)×3%;

[0027] When the contact angle is 120<θ≤160°, the dust suppressant addition ratio ω is controlled between 4% and 10%, which can be calculated using the formula ω=6%+(1-cosθ)×4%;

[0028] When the contact angle is 160<θ≤180°, the dust suppressant addition ratio ω is controlled between 5% and 12%, which can be calculated using the formula ω=7%+(1-cosθ)×5%;

[0029] (5) According to the dust suppressant addition ratio ω determined in step (3), the environmentally friendly and efficient dust suppressant based on the block copolymer is mixed and diluted with water and added to a spraying device, and the diluted dust suppressant is sprayed to the dust source by spraying.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] (1) In the dust suppressant provided by the present invention, the PMAA segment contains a large number of carboxyl groups, which can effectively adsorb the positively charged particles on the surface of the coal dust; its adsorption helps to improve the dust suppressant's fixation effect on dust particles; the presence of the PEGME segment gives the copolymer excellent hydrophilicity, which can reduce the surface tension of water, thereby enhancing the spreading effect of water on the surface of the coal dust; the PMAA segment can increase the viscosity of the solution, so that it forms a thicker wet film on the dust surface, thereby prolonging the duration of the dust suppression effect; PMAA-PEGME is relatively rarely used and has good environmental degradability, and will not cause additional environmental pollution. The PMAA part can remain relatively stable in an acidic or alkaline environment, which has certain advantages for an acidic or alkaline mine environment.

[0032] (2) The dust suppressant provided by the present invention significantly improves the capture and agglomeration effect of dust through the synergistic effect of the block copolymer PMAA-PEGME and the mineral adsorbent, thereby more quickly forming a protective film on the dust surface, inhibiting the diffusion and suspension of dust, and greatly improving the dust suppression effect; in addition, its good wettability enables it to evenly adhere to the dust particles to achieve comprehensive dust suppression.

[0033] (3) The dust suppressant provided by the present invention uses natural plant gum and degradable block copolymer as main components, does not contain toxic and harmful substances, ensures that it will not have adverse effects on the human body and the ecological environment during the application process, reduces secondary pollution to the environment, and meets the requirements of green environmental protection; at the same time, it can be naturally degraded after use, avoiding the burden of solid waste treatment and effectively reducing environmental pressure.

[0034] (4) Antifreeze agent is specially added to the dust suppressant provided by the present invention, which can maintain good fluidity and effectiveness in low temperature environment and can still be used normally below zero degrees, thereby ensuring continuous dust suppression effect under winter construction conditions and meeting the operation requirements in cold environment.

[0035] (5) The dust suppressant provided by the present invention contains mineral adsorbents and natural colloidal components, which can form a stable colloidal layer on the dust particles, thereby extending the duration of the dust suppression effect; the colloidal layer can form a solid protective film after air drying, effectively reducing the secondary flying of dust, thereby effectively reducing the frequency of use, reducing the cost of maintenance and re-spraying, and providing a lasting dust suppression effect. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with specific embodiments.

[0037] The PMAA-PEGME in the present invention is fully called polymethacrylic acid-polyethylene glycol methyl ether block copolymer.

[0038] Example 1

[0039] The invention discloses an environmentally friendly and efficient dust suppressant based on a block copolymer. The dust suppressant is composed of the following raw materials in percentage by mass: 10% PMAA-PEGME, 5% antifreeze agent, 3% natural plant gum (guar gum), 8% mineral adsorbent (bentonite), 0.5% surfactant (sodium dodecylbenzene sulfonate), 0.2% preservative (sodium benzoate), and the remaining component is deionized water.

[0040] The specific preparation process of PMAA-PEGME in this embodiment is as follows: using methacrylic anhydride as an activator, activating the terminal hydroxyl group of polyethylene glycol methyl ether at 80°C for 7h, dissolving and mixing the polyethylene glycol methyl ether terminal modification, methacrylic acid, initiator (azobisisobutyronitrile), chain transfer agent (thioglycolic acid) and anhydrous solvent (such as toluene), then performing block copolymerization at 70°C for 9h under nitrogen protection, removing the solvent by rotary evaporation or reduced pressure distillation after natural cooling, dissolving the reaction product in methanol or ether, and then dropping a large amount of ice ether to precipitate to obtain PMAA-PEGME. The amount of toluene is 1000mL (866g), the amount of polyethylene glycol methyl ether is 87g, the amount of methacrylic anhydride is 9.3g, the amount of methacrylic acid is 18.5g, the amount of azobisisobutyronitrile is 0.78g, and the amount of thioglycolic acid is 1.42g.

[0041] The specific preparation process of the antifreeze agent in this embodiment is as follows: 19.8g of ethylene glycol, 9.2g of propylene glycol and 13.2g of water are premixed for 5 minutes, and then 10.5g of urea is added to dissolve, and the mixture is transferred to a pressure-resistant reactor, heated to 130°C, and the pressure is controlled at 0.8MPa. The reaction is carried out for 1.5h to promote the condensation reaction of ethylene glycol, propylene glycol and urea. After the reaction is completed, the temperature and pressure are slowly lowered to room temperature and normal pressure, and the solution is filtered and unreacted impurities are removed to obtain the antifreeze agent.

[0042] The method for preparing an environmentally friendly and efficient dust suppressant based on a block copolymer in this embodiment comprises the following steps:

[0043] S1. Weigh each component according to the above mass percentage; put deionized water into a heating device, control the temperature at 40°C, then add PMAA-PEGME to the preheated deionized water, stir at 400 rpm, stir for 35 min, and stir evenly until completely dissolved;

[0044] S2, adding natural plant gum to the solution obtained in step S1, stirring at a speed of 180 rpm, stirring for 25 min, stirring until a viscous and uniform colloid is formed; then adding a mineral adsorbent to the colloid, stirring at a speed of 200 rpm, stirring for 18 min, stirring until the adsorbent is evenly distributed in the colloid;

[0045] S3, adding antifreeze to the sample obtained in step S2, stirring at a speed of 90 rpm for 8 min, stirring until the antifreeze is fully dissolved, and then adding surfactant, stirring at a speed of 130 rpm for 25 min;

[0046] S4, adding a preservative to the sample obtained in step S3, stirring at a speed of 90 rpm for 15 min, stirring until the preservative is completely dissolved, and then adjusting the pH value to 6.5 with a sodium hydroxide solution;

[0047] S5. Cool the sample obtained in step S4 to 25° C. at room temperature, and stir the sample during the cooling process to mix it evenly, thereby obtaining an environmentally friendly and efficient dust suppressant based on the block copolymer.

[0048] The method for using the environmentally friendly and efficient dust suppressant based on the block copolymer in this embodiment comprises the following steps:

[0049] (1) Use a dust sampler to collect dust at the work site;

[0050] (2) using a contact angle tester to measure the contact angle θ of the dust sample, and using the measured contact angle θ to characterize the hydrophobicity of the dust;

[0051] (3) According to the contact angle θ of the dust sample, determine the addition ratio of dust suppressant and water. The specific addition ratio is as follows:

[0052] When the contact angle is 0<θ≤40°, the dust suppressant addition ratio ω is controlled between 1% and 3%, which can be calculated using the formula ω=2%+(1-cosθ)×1%;

[0053] When the contact angle is 40<θ≤80°, the dust suppressant addition ratio ω is controlled between 2% and 5%, which can be calculated using the formula ω=3%+(1-cosθ)×2%;

[0054] When the contact angle is 80<θ≤120°, the dust suppressant addition ratio ω is controlled between 3% and 8%, which can be calculated using the formula ω=5%+(1-cosθ)×3%;

[0055] When the contact angle is 120<θ≤160°, the dust suppressant addition ratio ω is controlled between 4% and 10%, which can be calculated using the formula ω=6%+(1-cosθ)×4%;

[0056] When the contact angle is 160<θ≤180°, the dust suppressant addition ratio ω is controlled between 5% and 12%, which can be calculated using the formula ω=7%+(1-cosθ)×5%;

[0057] According to the dust suppressant addition ratio ω determined in step (3), the environmentally friendly and efficient dust suppressant based on the block copolymer is mixed with water and diluted and then added to the spraying device, and the diluted dust suppressant is sprayed to the dust source by spraying.

[0058] Example 2

[0059] The invention discloses an environmentally friendly and efficient dust suppressant based on a block copolymer. The dust suppressant is composed of the following raw materials in percentage by mass: 15% PMAA-PEGME, 3% antifreeze agent, 5% natural plant gum (xanthan gum), 5% mineral adsorbent (expanded diatomaceous earth), 1% surfactant (sodium alkyl sulfate), 0.1% preservative (potassium sorbate), and the remaining component is deionized water.

[0060] The specific preparation process of PMAA-PEGME, the specific preparation process of the antifreeze agent, the preparation method and the use method of the environmentally friendly and efficient dust suppressant based on the block copolymer in this example are all consistent with those in Example 1.

[0061] Example 3

[0062] The invention discloses an environmentally friendly and efficient dust suppressant based on a block copolymer. The dust suppressant is composed of the following raw materials in percentage by mass: 12% PMAA-PEGME, 4% antifreeze agent, 4% natural plant gum (guar gum), 6% mineral adsorbent (bentonite), 0.7% surfactant (sodium dodecylbenzene sulfonate), 0.3% preservative (sodium benzoate), and the remaining component is deionized water.

[0063] The specific preparation process of PMAA-PEGME, the specific preparation process of the antifreeze agent, the preparation method and the use method of the environmentally friendly and efficient dust suppressant based on the block copolymer in this example are all consistent with those in Example 1.

[0064] Example 4

[0065] The invention discloses an environmentally friendly and efficient dust suppressant based on a block copolymer. The dust suppressant is composed of the following raw materials in percentage by mass: 10% PMAA-PEGME, 5% antifreeze agent, 2% natural plant gum (xanthan gum), 10% mineral adsorbent (expanded diatomaceous earth), 0.6% surfactant (sodium alkyl sulfate), 0.2% preservative (potassium sorbate), and the remaining component is deionized water.

[0066] The specific preparation process of PMAA-PEGME, the specific preparation process of the antifreeze agent, the preparation method and the use method of the environmentally friendly and efficient dust suppressant based on the block copolymer in this example are all consistent with those in Example 1.

[0067] The contact angle of test dust 1 was measured by a contact angle tester to be 35°, and the contact angle of test dust 2 was 80°. Calculation showed that the required dust suppressant addition ratio for test dust 1 was 2.18%, and the required dust suppressant addition ratio for test dust 2 was 3.36%.

[0068] The dust suppressants prepared in Examples 1-4 were mixed with water in proportion and sprayed onto the surfaces of test dust 1 and test dust 2, respectively, and the dust suppression rate, dust suppression durability and moisture resistance tests were performed, respectively. The test results are shown in Table 1 below:

[0069] (1) Dust suppression rate test: The dust suppression rate can be calculated by setting the dust suppression agent spraying amount and spraying interval to be the same and measuring the dust concentration before and after spraying the dust suppression agent.

[0070] (2) Dust suppression persistence test: Dust suppression persistence refers to the ability of dust suppression effect to last over time. It can be evaluated by measuring the dust concentration after spraying multiple times at the same time interval to evaluate the effectiveness of dust suppressants within a certain time range. It is calculated by the ratio of the time when the dust concentration remains below 50% of the initial spraying concentration to the total evaluation time.

[0071] (3) Moisture resistance test: Moisture resistance refers to the ability of a dust suppressant to maintain its dust suppression effect in a humid environment, reflecting the stability of the dust suppressant when the humidity changes. The higher the moisture resistance, the more stable the dust suppressant effect in a humid environment. This index is evaluated by measuring the change in dust suppression effect in an environment with increased humidity. In this experimental example, it is calculated by the ratio of the dust suppression rate under standard humidity (RH 50%) and high humidity (RH 90%) environments.

[0072] Comparative Example 1 refers to spraying pure water onto the surfaces of test dust 1 and test dust 2 respectively.

[0073] Comparative Example 2 refers to spraying a polyoxyethylene ether mining dust suppressant produced by a certain manufacturer onto the surfaces of test dust 1 and test dust 2 respectively.

[0074] Table 1 Dust suppression test data for test dust 1 and test dust 2

[0075]

[0076] For the coal dust with a lower contact angle of 35°, the dust suppression rate of the four embodiments is higher than that of the coal dust group with a contact angle of 80°. This is because the surface of the coal dust with a lower contact angle is more easily wetted and covered by the dust suppressant, which enhances the dust suppression effect. The dust suppression rate of the coal dust group with a contact angle of 80° is slightly lower, but the effects of the four embodiments are still better than those of Comparative Examples 1 and 2.

[0077] The dust suppression durability of the 35° coal dust group with a lower contact angle is relatively high. Among the four examples, Example 2 has the highest durability of 75%. The dust suppression durability of the 80° coal dust group is slightly lower, but Examples 2 and 4 still perform better.

[0078] In the two groups of coal dust, the moisture resistance of the four embodiments is significantly better than that of the comparative example. The moisture resistance of the 35° coal dust group is slightly higher, indicating that under the condition of lower contact angle, the dust suppressant is more stable in a high humidity environment, while in the 80° coal dust group, although the moisture resistance of each embodiment is slightly reduced, it is still above 87%.

[0079] In summary, the environmentally friendly and efficient dust suppressant based on block copolymer provided by the present invention has better dust suppression durability and moisture resistance in high humidity and dusty environments such as coal preparation plants, and can significantly improve the effectiveness and stability of dust control.

Claims

1. An environmentally friendly and efficient dust suppressant based on block copolymers, characterized in that: The dust suppressant is composed of the following raw materials in percentage by mass: 10%-15% of PMAA-PEGME, 3%-5% of antifreeze agent, 2%-5% of natural plant gum, 5%-10% of mineral adsorbent, 0.5%-1% of surfactant, 0.1%-0.3% of preservative, and the remaining component is deionized water.

2. The environmentally friendly and efficient dust suppressant based on block copolymer according to claim 1, characterized in that: The preparation process of the PMAA-PEGME is as follows: using polyethylene glycol methyl ether as a hydrophilic segment precursor, methacrylic acid as a lipophilic segment precursor, azobisisobutyronitrile as an initiator, methacrylic anhydride or acryloyl chloride as an activator, thioglycolic acid as a chain transfer agent, and toluene as an anhydrous solvent, and preparing the PMAA-PEGME through an active free radical polymerization method.

3. The environmentally friendly and efficient dust suppressant based on block copolymer according to claim 2, characterized in that: The specific preparation process of the PMAA-PEGME is as follows: using methacrylic anhydride as an activator, activating the terminal hydroxyl group of polyethylene glycol methyl ether at 80-90°C for 6-8h, converting the terminal hydroxyl group of polyethylene glycol methyl ether into an acrylate group, then adding methacrylic acid, azobisisobutyronitrile, thioglycolic acid and toluene to mix, then carrying out a block copolymerization reaction at 60-80°C for 8-10h under nitrogen protection, removing the solvent by rotary evaporation or reduced pressure distillation after natural cooling, dissolving the reaction product in methanol or ether, and then dropping a large amount of icy ether to precipitate and obtain PMAA-PEGME.

4. The environmentally friendly and efficient dust suppressant based on block copolymer according to claim 3, characterized in that: Taking the mass of polyethylene glycol methyl ether as a reference, the amount of methacrylic anhydride is 10%-15% of the reference mass, the amount of methacrylic acid is 20%-30% of the reference mass, the amount of azobisisobutyronitrile is 0.5%-1% of the reference mass, the amount of thioglycolic acid is 1%-2% of the reference mass, and the amount of toluene is 10-15 times of the reference mass.

5. An environmentally friendly and efficient dust suppressant based on a block copolymer according to claim 1 or 2, characterized in that: The preparation process of the antifreeze agent is as follows: urea, ethylene glycol and propylene glycol are used as raw materials, and the antifreeze agent is prepared by pressurizing and heating in an aqueous solution to cause a condensation reaction.

6. The environmentally friendly and efficient dust suppressant based on block copolymer according to claim 5, characterized in that: The specific preparation process of the antifreeze agent is: premixing ethylene glycol, propylene glycol and water for 5-8 minutes, then adding urea to dissolve to obtain a reaction solution; transferring the reaction solution to a pressure-resistant reactor, heating to 120-150° C., controlling the pressure at 0.5-1 MPa, reacting for 1-2 hours to promote the condensation reaction of ethylene glycol, propylene glycol and urea, and slowly cooling and depressurizing to room temperature and normal pressure after the reaction is completed, filtering the solution and removing unreacted impurities to obtain the antifreeze agent.

7. The environmentally friendly and efficient dust suppressant based on block copolymer according to claim 6, characterized in that: The specific preparation process of the antifreeze agent is as follows: the molar ratio of urea, ethylene glycol and propylene glycol is 1:(1.5-2.5):(0.5-1.5), the mass fraction of urea in the reaction liquid is 15%-25%, the mass fraction of ethylene glycol in the reaction liquid is 35%-45%, and the mass fraction of propylene glycol in the reaction liquid is 10%-25%.

8. An environmentally friendly and efficient dust suppressant based on a block copolymer according to claim 1 or 2, characterized in that: The natural plant gum is xanthan gum or guar gum; the mineral adsorbent is bentonite or expanded diatomaceous earth; the preservative is sodium benzoate or potassium sorbate; the surfactant is an anionic surfactant, and the anionic surfactant is sodium dodecylbenzene sulfonate or sodium alkyl sulfate.

9. A method for preparing an environmentally friendly and efficient dust suppressant based on a block copolymer as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Weigh each component by mass percentage; put deionized water into a heating device, control the temperature at 40-50°C, then add PMAA-PEGME to the preheated deionized water, stir at a speed of 300-500rpm, stir for 30-40min, and stir evenly until completely dissolved; S2, adding natural plant gum to the solution obtained in step S1, stirring at a speed of 150-200 rpm, stirring for 20-30 min, stirring until a viscous and uniform colloid is formed; then adding a mineral adsorbent to the colloid, stirring at a speed of 150-200 rpm, stirring for 10-20 min, stirring until the adsorbent is evenly distributed in the colloid; S3, adding antifreeze to the sample obtained in step S2, stirring at a speed of 60-100 rpm, stirring for 5-10 min, stirring until the antifreeze is fully dissolved, and then adding surfactant, stirring at a speed of 100-150 rpm, stirring for 20-30 min; S4, adding a preservative to the sample obtained in step S3, stirring at a speed of 60-100 rpm for 10-20 min, stirring until the preservative is completely dissolved, and then adjusting the pH value to 5.5-7.0 with a sodium hydroxide solution; S5. Cool the sample obtained in step S4 to 25° C. at room temperature, and stir the sample during the cooling process to mix it evenly, thereby obtaining an environmentally friendly and efficient dust suppressant based on the block copolymer.

10. A method for using the environmentally friendly and efficient dust suppressant based on a block copolymer as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Use a dust sampler to collect dust at the work site; (2) using a contact angle tester to measure the contact angle θ of the dust sample, and using the measured contact angle θ to characterize the hydrophobicity of the dust; (3) According to the contact angle θ of the dust sample, determine the addition ratio of dust suppressant and water. The specific addition ratio is as follows: When the contact angle is 0<θ≤40°, the dust suppressant addition ratio ω is controlled between 1% and 3%, which can be calculated using the formula ω=2%+(1-cosθ)×1%; When the contact angle is 40<θ≤80°, the dust suppressant addition ratio ω is controlled between 2% and 5%, which can be calculated using the formula ω=3%+(1-cosθ)×2%; When the contact angle is 80<θ≤120°, the dust suppressant addition ratio ω is controlled between 3% and 8%, which can be calculated using the formula ω=5%+(1-cosθ)×3%; When the contact angle is 120<θ≤160°, the dust suppressant addition ratio ω is controlled between 4% and 10%, which can be calculated using the formula ω=6%+(1-cosθ)×4%; When the contact angle is 160<θ≤180°, the dust suppressant addition ratio ω is controlled between 5% and 12%, which can be calculated using the formula ω=7%+(1-cosθ)×5%; (4) According to the dust suppressant addition ratio ω determined in step (3), the environmentally friendly and efficient dust suppressant based on the block copolymer is mixed and diluted with water and added to a spraying device, and the diluted dust suppressant is sprayed to the dust source by spraying.

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