Coal spraying type crusting dust suppressant

Abstract

The invention discloses a coal spraying type crusting dust suppressant, and belongs to the technical field of dust suppressant preparation. The coal spraying type crusting dust suppressant is prepared from the following raw materials: a fermented straw mixture, starch, alkali, sodium carboxymethyl cellulose, polyacrylamide, a solvent A, an auxiliary material and a solvent B, the auxiliary materials comprise liquid soap, glycerol, lauryl sodium sulfate, sodium alginate, rosin, modified polyvinyl alcohol and borax; the solvent A and the solvent B are water. The coal spraying type crusting dust suppressant can effectively reduce dust flying in the coal transportation process, the cost of the dust suppressant can be reduced, the environmental protection property of the dust suppressant is improved, the problems that a traditional dust suppressant is high in cost, few in raw material source, large in pollution and the like are effectively solved, and a new thought is provided for subsequent development of the dust suppressant.

Description

Technical Field

[0001] The invention relates to the technical field of dust suppressant preparation, in particular to a coal spraying type crust dust suppressant. Background Art

[0002] During coal transportation, dust on the surface of coal will be scattered or blown up due to train bumps and wind, which will not only cause environmental pollution, but also pose a threat to equipment and railway transportation safety. The scattered coal dust will aggravate the compaction of rails, increase the cost and difficulty of track maintenance, and even affect the normal operation of railway communication systems.

[0003] At present, the main methods to prevent the dust on the surface of coal from scattering or flying include watering, covering, closed transportation and chemical dust suppressant. Among them, the watering method is to reduce the flying of dust by sprinkling water on the surface of coal. This method is not effective in dry environment because water evaporates easily, and frequent watering is required, and it is difficult to achieve long-term and stable dust suppression effect; the covering method is to cover the coal with tools such as tarpaulins and dustproof nets, which can effectively isolate the wind and prevent the dust from flying. This method requires a lot of manpower and material resources and is difficult to implement in the automated loading and unloading system; the closed transportation method is to isolate the coal from the outside air by closing the carriage or using containers for transportation, thereby reducing the generation of dust. This method is difficult to fully match the existing automated loading and unloading system and has a limited scope of application; the chemical dust suppressant method is to spray dust suppressants on the surface of coal to form a strong adhesive solidified layer to prevent dust from escaping. This method is low-cost and does not interfere with the automated loading and unloading system. It is one of the more ideal dust suppression methods at present. However, the current chemical dust suppressants have problems such as low technical maturity (not verified by large-scale industrial applications), limited application scope (only applicable to specific types of coal transportation environments, and may not be suitable for other types of materials or environments), environmental protection effects need to be improved (environmental protection performance may still have room for improvement, especially in reducing pollutant emissions), complex technology (the preparation process is relatively complex, requiring special equipment and technical conditions, increasing production costs and technical barriers), high cost, low applicability (designed for specific types of coal transportation scenarios, and may not be effective for other types of coal or transportation conditions), etc., and poor moisture retention and dust suppression performance may cause accidents caused by dust pollution during transportation. Therefore, it is necessary to improve the existing dust suppressants to improve their moisture retention and dust suppression performance. Summary of the invention

[0004] The purpose of the present invention is to provide a coal spraying type crust dust suppressant to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention: A coal spraying type crust dust suppressant, the raw materials of which include a fermented straw mixture, starch, alkali, sodium carboxymethyl cellulose, polyacrylamide, solvent A, auxiliary materials and solvent B;

[0007] The auxiliary materials include: hand sanitizer, glycerol, sodium lauryl sulfate, sodium alginate, rosin, modified polyvinyl alcohol and borax;

[0008] The solvent A and the solvent B are water.

[0009] Furthermore, the mass ratio of the fermented straw mixture, starch and alkali is 27:70:1;

[0010] The mass ratio of the total mass of the fermented straw mixture, starch, and alkali to the mass ratio of sodium carboxymethyl cellulose and polyacrylamide is 7:2:1;

[0011] The mass ratio of the total mass of the fermented straw mixture, starch, alkali, sodium carboxymethyl cellulose, polyacrylamide and solvent A is 1:2;

[0012] The usage ratio of the hand sanitizer, glycerol and dodecyl sulfuric acid is 71.8 mL: 10 mL: 15 g;

[0013] The mass ratio of the total mass of the hand sanitizer, glycerol and sodium lauryl sulfate to the mass ratio of the solvent B is 1:99;

[0014] The ratio of the total mass of the fermented straw mixture, starch, alkali, sodium carboxymethyl cellulose, polyacrylamide to the total mass of hand sanitizer, glycerol and dodecyl sulfuric acid is 10:1;

[0015] The amounts of sodium alginate, rosin, modified polyvinyl alcohol and borax used in the coal spray crust dust suppressant are 30 g / L sodium alginate, 10 g / L rosin, 5 g / L modified polyvinyl alcohol and 10 g / L borax respectively.

[0016] Furthermore, the method for preparing the fermented straw mixture comprises the following steps:

[0017] The agricultural waste is dried, ball-milled, and then soaked in water, and then ultrasonically treated. Subsequently, a microbial liquid is added for fermentation treatment. After washing, the waste is dried and ball-milled to obtain the fermented straw mixture.

[0018] Furthermore, the power of the ultrasonic treatment is 500 W and the time is 30 min; the cavitation effect of the ultrasonic wave can loosen the fiber structure of the straw, exposing more active sites, which is conducive to better combination with other raw materials.

[0019] The fermentation temperature is 30° C. and the fermentation time is 48 hours. During the fermentation process, microorganisms can decompose part of the lignin and cellulose in the agricultural waste to produce more small molecules, which can improve the compatibility of the agricultural waste with other raw materials and enhance the dust suppression effect.

[0020] Furthermore, the agricultural waste includes one or more of crop straw, bean pod skin and grain husk.

[0021] Furthermore, the preparation method of the modified polyvinyl alcohol (polymer) comprises the following steps:

[0022] The modified polyvinyl alcohol is obtained by mixing polyvinyl alcohol and an ionic liquid (such as 1-butyl-3-methylimidazolium chloride solution) for reaction (stirring at 60° C. for 2 hours to allow cross-linking reaction to occur between polyvinyl alcohol molecular chains).

[0023] Modified polyvinyl alcohol has better bonding strength, mechanical properties and stability. Through the mixed reaction with ionic liquid, cross-linking reaction occurs between the molecular chains of polyvinyl alcohol to form a more stable network structure. When the dust suppressant is applied to the surface of coal, this structure can better wrap the coal particles, enhance the bonding force between the particles and between the particles and the dust suppressant, effectively prevent the scattering of coal during transportation, loading and unloading, and reduce dust generation. The cross-linked molecular structure gives the modified polyvinyl alcohol better tensile and impact resistance. In actual use scenarios, when the coal pile is impacted by external forces (such as wind, loading and unloading collisions, etc.), the dust suppressant layer can better maintain its integrity and is not easy to break, thereby continuing to play a dust suppression role. This helps to maintain the stability of the surface of the coal pile and reduce dust flying caused by the destruction of the dust suppressant layer. Modified polyvinyl alcohol has good physical and chemical stability. When the coal is in a high temperature environment (such as exposed to the sun in summer or close to heating equipment), the modified polyvinyl alcohol in the dust suppressant will not soften, flow or lose its adhesive properties due to the increase in temperature, thereby ensuring that the dust suppressant can still effectively adhere to the coal surface under high temperature conditions, forming a stable dust suppression layer, and can play a better role in the dust suppressant.

[0024] Glycerol can be added selectively according to different situations. For example, glycerol can be added to inhibitors used for coal powder transportation or coal stacking in power plants in cold northern regions, but it is not needed in the south.

[0025] The coal spraying type crust dust suppressant of the present invention can be used in large-scale industrial applications, is suitable for various coal transportation environments, has high environmental protection, is simple in preparation method, is low in cost, and has excellent moisture retaining and dust suppressing effects, thus overcoming the problems existing in existing dust suppressants.

[0026] The second technical solution of the present invention is a method for preparing the above-mentioned coal spraying type crust dust suppressant, comprising the following steps:

[0027] The fermented straw mixture, starch and alkali are mixed evenly, and then sodium carboxymethyl cellulose and polyacrylamide are added. After mixing evenly, solvent A is added. After heating reaction, auxiliary materials and solvent B are added. After microwave-assisted blending, natural cooling is carried out (to avoid excessive cooling that causes uneven crusting or cracking), to obtain the coal spray crust dust suppressant.

[0028] Further, the heating reaction is to react at 60-70°C for 1-2h, and then at 80-90°C for 1-2h. Preliminary reaction (60-70°C, 1-2h) This stage mainly involves starch gelatinization and preliminary reaction with other substances. Starch begins to gelatinize at 60-70°C to form a viscous colloid, which wraps around the surface of agricultural waste particles, increasing the viscosity and adhesion of the system. At the same time, within this temperature range, small molecules produced by microbial fermentation begin to react chemically with starch, alkali (sodium hydroxide) and active ingredients in agricultural waste to form a preliminary network structure, laying the foundation for further subsequent reactions. For example, during starch gelatinization, the starch molecular chain gradually unfolds, and the contact area with other raw materials increases, which promotes the chemical reaction between each other and improves the stability of the system. Deep reaction (80-90°C, 1-2h), as the temperature rises to 80-90°C, the chemical reaction rate accelerates, and the reaction between the raw materials is more sufficient. Starch and alkali further react to form more stable chemical bonds, enhancing the bonding strength. Cellulose and other components in agricultural waste are further degraded and modified under high temperature and alkaline conditions, and better integrated with other components, improving the comprehensive performance of dust suppressants. For example, at this temperature, the crystalline structure of cellulose is destroyed, some glycosidic bonds are broken, and more soluble sugars and oligosaccharides are generated. These substances work synergistically with other raw materials to enhance the film-forming and adsorption properties of dust suppressants.

[0029] Furthermore, the power of the microwave-assisted blending is 800 W, and the heating is intermittent, heating for 30 seconds, stopping for 10 seconds, and repeating 3 times.

[0030] Microwave-assisted blending can increase the movement speed of raw material molecules: make the raw material molecules move quickly and promote uniform mixing between the raw materials.

[0031] Microwave-assisted blending can enhance reaction efficiency: speed up chemical reactions and increase reaction rates.

[0032] Microwave-assisted blending can improve mixing uniformity: breaking the agglomeration state of the raw materials, allowing different raw material molecules to collide and diffuse more fully with each other, and achieving more uniform dispersion.

[0033] Microwave-assisted blending can optimize the uniformity of product structure: a more uniform structure can be formed during the subsequent reaction and curing process. For example, in the preparation of coal spray-type crust suppressant, the dust suppressant can form a uniform film layer or crust on the coal surface, thereby enhancing its resistance to damage.

[0034] Microwave-assisted blending can improve performance stability: make the interaction between the components more sufficient and stable, and make the product performance more stable under different environmental conditions (such as temperature, humidity changes, etc.).

[0035] Microwave-assisted blending can improve the hydrophilicity and biodegradability of dust suppressants.

[0036] After drying, ball milling, ultrasonic treatment and fermentation of agricultural waste, starch and alkali are added and heated to react, at this time, a certain degree of preliminary crusting will be formed. During the heating process, the starch gelatinizes, interacts with agricultural waste and other components, and begins to form a viscous substance, initially building a relatively loose structural framework with certain adhesion and stability, which can play a preliminary role in agglomerating and fixing coal particles. For example, in laboratory simulation experiments, a thin layer of viscous substance can be seen on the surface of coal samples after processing in the main material preparation stage, which can maintain a certain morphological integrity under slight vibration. When auxiliary materials (such as hand sanitizer, glycerol, sodium dodecyl sulfate, sodium alginate, rosin, modified polyvinyl alcohol, borax, etc.) are added, the crusting process is further developed and strengthened.

[0037] Thickeners such as sodium alginate, rosin and modified polyvinyl alcohol increase the viscosity of the solution, making the system thicker, further filling and reinforcing the initially formed crust structure. The film-forming property of sodium alginate allows it to form a continuous film on the surface of coal, which can enhance the dust suppressant's wrapping and bonding of coal particles; the viscosity and adsorption capacity of rosin help to improve the firmness of the crust and better absorb coal dust; modified polyvinyl alcohol improves the stability and strength of the overall structure.

[0038] Borax can "solidify" part of the solvent, accelerate the crusting process, and make the crust layer form faster and reach a certain hardness. It participates in the construction of the crust structure, and works synergistically with other ingredients to improve the strength and stability of the crust, so that the crust can better resist the influence of external factors (such as wind, vibration, etc.).

[0039] When starch is heated to a certain temperature (about 60°C), it will gelatinize, turning the starch solution into a viscous, uniform, transparent paste solution. After comparing different types of edible starch and soluble starch, it was found that under the same conditions, edible starch (corn starch or potato starch) slurry has stronger gelatinization properties, higher viscosity, and better covering effect. The addition of alkali (such as sodium hydroxide, which can promote the gelatinization of starch and the solidification of dust suppressants) is because starch is more conducive to gelatinization in an alkaline environment.

[0040] After the addition of auxiliary materials, the crust structure is transformed from a preliminary loose framework to a more dense, tough and stable whole. A more complex network structure is formed inside, and the various components are intertwined and synergistic, which improves the crust's ability to resist damage. Scanning electron microscopy observations show that the surface of the crust layer after adding auxiliary materials is smoother and flatter, the pores are significantly reduced, and the structure is more uniform and dense.

[0041] The crust reinforced with auxiliary materials can more effectively prevent the flying and scattering of coal dust. In actual application scenarios, such as the bumps and vibrations during coal transportation, and the wind blowing during open-air stacking, the crust layer can remain intact, reducing the generation and spread of dust. Experimental data show that in simulated transportation and stacking experiments, the dust emission of coal treated with dust suppressants after adding auxiliary materials is significantly reduced by about 50-70% compared with coal treated only with the main materials, effectively protecting the environment and reducing coal losses.

[0042] The step-by-step encrustation method of the present invention ensures the stability and effectiveness of the dust suppressant during long-term use. Whether in the short-term coal transportation process or in the long-term open-air storage scenario, the encrustation layer can continue to play a dust suppression role, reduce the frequency of maintenance and replenishment of dust suppressants, and reduce costs. For example, after the coal piles that have been stacked for a long time at the coal port are treated, the surface encrustation remains good during the observation period of several months, and dust pollution is effectively controlled.

[0043] The dust suppressant prepared by the present invention can optimize the crusting performance by adjusting the type and amount of auxiliary materials according to different coal characteristics and use environments.

[0044] Thickeners such as sodium alginate, rosin and modified polyvinyl alcohol can increase the viscosity of the system.

[0045] As the viscosity increases, the dust suppressant can better wrap the coal dust particles, making the bonding force between the particles stronger. For example, during the coal transportation process, the bumps and vibrations of the vehicle will cause the coal particles to rub and collide with each other. If the viscosity of the dust suppressant is insufficient, the dust particles will easily break away from the crust layer and fly.

[0046] The increased viscosity helps form a more stable and continuous crust layer on the surface of the coal. This crust can resist the erosion of coal by external factors (such as wind, rain, etc.) and reduce the release of dust. For example, in an open-air coal yard, the crust layer formed by high-viscosity dust suppressants can remain intact in windy weather, effectively preventing dust from being blown up by the wind.

[0047] The increase in viscosity has significant benefits for coal spray crust dust suppressants in terms of improving dust suppression effects, enhancing adhesion and anti-interference capabilities, etc., which helps to better achieve dust control during coal transportation and storage, and reduce environmental pollution and resource waste.

[0048] Sodium alginate is a natural polysaccharide extracted from seaweed, which has good film-forming and thickening properties. When it is used in conjunction with straw, alkali, starch, modified polyvinyl alcohol, etc., it can form a tough and breathable film on the surface of coal to enhance the dust suppression effect. Rosin is a natural resinous substance with viscosity and flammability. It can be filled in the network structure formed by starch and modified polyvinyl alcohol to increase the viscosity of the dust suppressant and improve the adsorption capacity of coal dust. And because sodium alginate and rosin are flammable themselves, they will burn during the coal combustion process and will not affect the quality of the coal.

[0049] The third technical solution of the present invention: an application of the above-mentioned coal spray-type crust dust suppressant in coal dust suppression.

[0050] Furthermore, the application method comprises: diluting the coal spray-type crust dust suppressant and water in a mass ratio of 1:10 to 1:20 to prepare a working solution suitable for spraying;

[0051] The working fluid is evenly sprayed on the coal surface through a dedicated spraying system to ensure that all areas to be dust suppressed are covered. The spray pressure and flow rate are adjusted according to the humidity, particle size and transportation speed of the coal to achieve the best dust suppression effect;

[0052] After spraying, the moisture content and dust emission of the coal surface should be monitored regularly to ensure that the dust suppression effect reaches the expected target;

[0053] According to the coal consumption and the use of dust suppressant, new dust suppressant should be added in time, and the spraying system should be cleaned regularly to keep it in good working condition.

[0054] Effect of coal humidity on spray parameters:

[0055] (1) Humidity range classification and characteristics

[0056] Coal humidity can be roughly divided into low humidity (less than 10%), medium humidity (10-30%) and high humidity (greater than 30%). Low-humidity coal has a dry surface and strong water absorption, so dust suppressants are easily absorbed, but it is also easy for the crust layer to dry out and crack due to lack of moisture. Medium-humidity coal is in a relatively ideal state, and it is relatively easy for dust suppressants to adhere and solidify on its surface. High-humidity coal has more moisture on its surface, which may affect the adhesion effect of dust suppressants and easily dilute the dust suppressants.

[0057] (2) Spray parameters at different humidity

[0058] Low-humidity coal: The spray pressure can be controlled at 0.3-0.5MPa. The lower pressure helps the dust suppressant to slowly and evenly penetrate into the coal particles, avoiding the surface dust from being blown away due to excessive pressure. The flow rate can be set to 8-12L / min to ensure that there is enough dust suppressant covering the coal surface to form a stable crust layer. For example, in some coal yards in arid areas, the humidity of the coal is low. After spraying with such parameters, the thickness of the crust layer is uniform, which can effectively suppress the flying of dust, and the dust suppression rate can reach more than 85%.

[0059] Medium-humidity coal: The spray pressure is more suitable at 0.2-0.4MPa. At this time, the dust suppressant can adhere to the coal surface well and form a continuous film layer. The flow rate can be adjusted to 6-10L / min, which can not only meet the dust suppression needs but also avoid waste. In actual coal mine transportation, medium-humidity coal is more common. After spraying according to this parameter, the crust layer on the surface of the coal is well intact during transportation. After a certain distance of transportation, the crust layer shedding rate is less than 10%.

[0060] High humidity coal: Due to the high surface moisture, a higher spray pressure is required to penetrate the water layer so that the dust suppressant can contact the coal particles. The pressure can be increased to 0.4-0.6MPa. However, the flow rate should be appropriately reduced to 4-8L / min to prevent excessive dilution of the dust suppressant. For example, in the coal storage area of ​​the port, some coal may be subject to high humidity. With this parameter combination, the dust suppressant can form an effective crust on the surface of the coal, suppress dust emission, and maintain a certain dust suppression effect after rain.

[0061] Effect of coal particle size on spray parameters:

[0062] (1) Particle size range classification and characteristics

[0063] Coal particle size can be divided into small particle size (less than 6mm), medium particle size (6-50mm) and large particle size (greater than 50mm). Small particle size coal has a large surface area and small pores; medium particle size coal has a moderate particle size and a relatively smooth surface; large particle size coal has a rough surface and large pores.

[0064] (2) Spray parameters at different particle sizes

[0065] Small-particle coal: Due to its large surface area, it requires more dust suppressant coverage, and the spray flow rate should be large, which can be set to 10-15L / min. At the same time, in order to prevent the dust suppressant from being unable to enter the pores, the spray pressure should not be too high, 0.2-0.3MPa is more appropriate. In some small coal mines where fine coal is stacked after screening, after spraying with this parameter, the dust suppressant can fully fill the pores between coal particles, forming a dense crust layer, effectively preventing dust from escaping, and reducing dust emissions by about 90%.

[0066] Medium-sized coal: The spray pressure is within the range of 0.3-0.5 MPa, which can make the dust suppressant adhere to the coal surface better, and the flow rate can be controlled at 8-12 L / min. During the transportation and storage of medium-sized coal, the dust suppressant forms a uniform film layer on the coal surface when sprayed according to this parameter. The crust layer has good impact resistance and wind erosion resistance. Under the simulated wind force, the dust loss rate is less than 5%.

[0067] Large-particle coal: Large-particle coal has a rough surface, and a higher spray pressure is required to ensure that the dust suppressant infiltrates the surface. The pressure can be between 0.4 and 0.6 MPa. The flow rate is adjusted according to the coal stacking density and coverage requirements, generally 6 to 10 L / min. In the raw coal storage area of ​​large open-pit coal mines, after large-particle coal is sprayed with these parameters, the dust suppressant can penetrate into the pores and cracks on the surface of the coal to form a strong crust. Even during mechanical loading and unloading, the crust layer can maintain good integrity and reduce dust generation.

[0068] Effect of coal transport speed on spray parameters:

[0069] (1) Speed ​​range classification and impact

[0070] Coal transportation speed can be divided into low speed (less than 80km / h), medium speed (80-120km / h) and high speed (greater than 120km / h). The faster the transportation speed, the faster the dust suppressant needs to form effective coverage on the coal surface, and the uniformity and stability must be ensured.

[0071] (2) Spray parameters at different speeds

[0072] Low-speed transportation: The spray pressure is 0.2-0.3MPa. The low pressure is enough to make the dust suppressant evenly adhere to the coal surface. The flow rate can be set to 6-8L / min. In some short-distance transportation scenarios within coal mines, the coal transportation speed is slow. With this parameter spraying, the dust suppressant can form a good crust layer on the coal surface, and the crust layer is not easily damaged during transportation, effectively suppressing dust generation and keeping the dust concentration in the transportation environment at a low level.

[0073] Medium-speed transportation: The spray pressure is adjusted to 0.3-0.4MPa and the flow rate is 8-10L / min. Medium-speed transportation is more common in coal railway transportation or medium-scale conveyor belt transportation. Such parameter settings can ensure that the dust suppressant quickly forms a stable crust layer on the coal surface, adapt to the vibration and airflow during transportation, ensure the dust suppression effect, and reduce pollution to the railway or surrounding environment.

[0074] High-speed transportation: In order to make the dust suppressant cover the coal surface in a short time, the spray pressure needs to be increased to 0.4-0.5MPa and the flow rate needs to be increased to 10-15L / min. In modern large-scale coal port loading and unloading and high-speed conveyor belt transportation, these parameters are used during high-speed transportation. The dust suppressant can quickly form a continuous and tough crust layer on the coal surface, effectively preventing dust from flying during high-speed movement and protecting the environment around the port and transportation line.

[0075] In practical applications, it is necessary to flexibly adjust the spray pressure and flow parameters according to the specific humidity, particle size and transportation speed of the coal to achieve the best dust suppression effect. At the same time, factors such as the cost of dust suppressants and the operating efficiency of the equipment should also be considered to achieve efficient, economical and environmentally friendly coal dust control.

[0076] The present invention discloses the following technical effects:

[0077] (1) The coal-spraying type dust suppressant of the present invention can effectively reduce the flying dust during coal transportation, reduce the cost of the dust suppressant, and improve the environmental friendliness of the dust suppressant. It effectively solves the problems of high cost, limited raw material sources, and high pollution of traditional dust suppressants, and provides a new idea for the subsequent development of dust suppressants.

[0078] (2) In specific implementation, the raw material ratio and preparation process can be appropriately adjusted according to actual conditions to adapt to different coal types and transportation environments. In addition, the present invention can further optimize the formula and preparation process according to the needs of actual application scenarios to achieve better dust suppression effect and environmental protection.

[0079] (3) The coal spraying type crust suppressant of the present invention can reduce the amount of non-combustible additives used, thereby solving the problem that the use of dust suppressants during coal transportation causes the ash content of coal to increase and the calorific value of coal to decrease.

[0080] (4) The coal spraying type crust dust suppressant of the present invention effectively solves the problem that the existing dust suppressants have poor moisture retention and dust suppression effects during use, reduces coal losses during transportation, and can reduce safety risks during transportation, which is also beneficial to environmental protection and reduction of environmental pollution.

[0081] (5) The present invention adheres to the basic idea of ​​"treating waste with waste" and prepares a green and environmentally friendly coal dust suppressant, which is non-toxic and harmless to human body and environment during preparation and use, and has high dust suppression efficiency and dust suppression cycle. DETAILED DESCRIPTION

[0082] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0083] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0084] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0085] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0086] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0087] The “parts” described in the following examples are all “parts by mass”.

[0088] The preparation method of the modified polyvinyl alcohol used in the following embodiments of the present invention is: polyvinyl alcohol (molecular weight of 10000), 1-butyl-3-methylimidazolium tetrafluoroborate and deionized water are mixed in a mass ratio of 40:5:80, stirred at 60°C for 2h to allow cross-linking reaction to occur between the polyvinyl alcohol molecular chains, and then dried to obtain modified polyvinyl alcohol.

[0089] Example 1

[0090] Preparation method of coal spraying type crust dust suppressant:

[0091] (1) Agricultural waste, rice husks, and cottonseed husks (the mass ratio of agricultural waste straw, rice husks, and cottonseed husks is 3:2:1) from which moldy substances have been removed are crushed by a crusher to a particle size of less than 5 mm and then dried. The particles are then placed in a simple ball mill modified by welding an electric wire winder and a stainless steel tank and processed for 20 minutes to reduce the particle diameter to about 100 nm, thereby obtaining agricultural waste powder.

[0092] (2) The agricultural waste powder is subjected to ultrasonic pretreatment (power of 400 W, time of 30 min) to obtain pretreated agricultural waste powder.

[0093] (3) The pretreated agricultural waste powder was soaked in water (the ratio of the pretreated agricultural waste powder to water was 1:2), and then ultrasonically treated for 30 minutes with a power of 500 W to obtain a straw mixture.

[0094] (4) The straw mixture was mixed with microbial liquid (crude fiber degrading bacteria, microbial agent purchased from Guangzhou Weiyuan Biotechnology Co., Ltd., product number: WYCP-FSJ-002, diluted 1000 times before use) at a mass ratio of 1:20, fermented at 30°C for 48 hours, filtered to remove the foam, washed three to five times and dried, and then added to a simple ball mill and processed for 20 minutes to obtain the fermented straw mixture powder.

[0095] (5) The fermented straw mixture powder, starch and sodium hydroxide are mixed in a mass ratio of 27:70:3 to obtain a mixed powder.

[0096] (6) After mixing the mixed powder, sodium carboxymethyl cellulose and polyacrylamide (molecular weight of 8 million) in a mass ratio of 7:2:1, add aqueous solvent A (the mass ratio of the total mass of the mixed powder, sodium carboxymethyl cellulose and polyacrylamide to the mass ratio of aqueous solvent A is 1:2) and stir continuously to make the mixture uniform, then heat to 70°C and stir continuously for 2 hours, continue to heat to 80°C, react for 1 hour, and then add auxiliary materials (auxiliary materials include: Libai hand sanitizer, glycerol, sodium lauryl sulfate, sodium alginate, rosin, modified polyvinyl alcohol and borax; wherein the amount ratio of Libai hand sanitizer, glycerol and sodium lauryl sulfate is 71.8mL:10mL:15g; the total mass ratio of the mixed powder, sodium carboxymethyl cellulose and polyacrylamide to the total mass ratio of Libai hand sanitizer, glycerol and sodium lauryl sulfate is 10:1); The contents of sodium alginate, rosin, modified polyvinyl alcohol and borax in the coal spray-type crust dust suppressant are 30 g / L sodium alginate, 10 g / L rosin, 5 g / L modified polyvinyl alcohol and 10 g / L borax) and aqueous solvent B (the mass ratio of the total mass of Liby hand sanitizer, glycerol and sodium dodecyl sulfate to the aqueous solvent B is 1:99), and microwave-assisted blending is adopted (intermittent heating in a microwave oven with a power of 800 W, heating for 30 seconds, stopping for 10 seconds, and repeating 3 times), then the heating is stopped immediately, the container is removed to avoid the residual heat from continuing to heat the container, and it is left to cool naturally, and it is packaged after vacuum dehydration treatment (the packaging material should be a non-hygroscopic and wear-resistant material, such as a plastic barrel or a woven bag, to ensure the quality stability of the dust suppressant during transportation and storage), so as to obtain a coal spray-type crust dust suppressant.

[0097] Comparative Example 1

[0098] Same as Example 1, except that sodium alginate is replaced with modified polyvinyl alcohol of equal mass.

[0099] Comparative Example 2

[0100] Same as Example 1, except that the addition of borax is omitted.

[0101] Comparative Example 3

[0102] The same as Example 1, except that step (4) is not performed.

[0103] Comparative Example 4

[0104] The same as Example 1, except that the modified polyvinyl alcohol is replaced by polyacrylamide (molecular weight of 8 million) of equal mass.

[0105] Comparative Example 5

[0106] Same as Example 1, except that starch is replaced with lotus root starch of equal mass.

[0107] Comparative Example 6

[0108] Same as Example 1, except that sodium carboxymethyl cellulose is replaced with an equal mass of polyvinyl alcohol (molecular weight of 10000).

[0109] Effect Example 1

[0110] The coal spray-type crust dust suppressant prepared in Example 1 or Comparative Examples 1 to 6 is diluted with water at a mass ratio of 1:20 to prepare a dust suppressant working solution;

[0111] The coal (humidity of the coal is 20%, and the particle size is 20-40 mm) is loaded into 8 identical train carriages (13 meters long and 2.9 meters wide). The coal pile area in each carriage is 37.7 m 2 ;

[0112] The dust suppressant working liquid is evenly sprayed on the coal surface through a special spraying system to ensure that all areas to be dust suppressed are covered (i.e. the amount of dust suppressant is 15g / m 2 For coal, 300 mL of dust suppressant working liquid is sprayed per square meter), the spray pressure of the dust suppressant working liquid is 0.4 MPa and the flow rate is 10 L / min.

[0113] After spraying the dust suppressant working solution, the car was left to stand for 2 hours before starting the transportation test. The transportation speed was 80 km / h. The coal loss rate was measured after 12 hours of transportation. The car without dust suppressant spraying was used as the control group. The results are shown in Table 1.

[0114] Coal loss rate = (mass after standing for 2 hours - mass after transporting for 12 hours) / mass after standing for 2 hours × 100%.

[0115] Table 1 Coal loss rate measured after 48 hours of transportation

[0116] Grouping Coal loss rate (wt.%) Example 1 0.15 Comparative Example 1 0.26 Comparative Example 2 0.17 Comparative Example 3 0.35 Comparative Example 4 0.27 Comparative Example 5 1.24 Comparative Example 6 0.42 Control group 3.52

[0117] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A coal spraying type crust dust suppressant, characterized in that: The raw materials include fermented straw mixture, starch, alkali, sodium carboxymethyl cellulose, polyacrylamide, solvent A, auxiliary materials and solvent B; The auxiliary materials include: hand sanitizer, glycerol, sodium lauryl sulfate, sodium alginate, rosin, modified polyvinyl alcohol and borax; The solvent A and the solvent B are water.

2. The coal spraying type crust dust suppressant according to claim 1, characterized in that: The mass ratio of the fermented straw mixture, starch and alkali is 27:70:1; And / or, the mass ratio of the total mass of the fermented straw mixture, starch, alkali to the mass ratio of sodium carboxymethyl cellulose and polyacrylamide is 7:2:1; and / or, the mass ratio of the total mass of the fermented straw mixture, starch, alkali, sodium carboxymethyl cellulose, polyacrylamide and solvent A is 1:2; and / or, the usage ratio of the hand sanitizer, glycerol and dodecyl sulfuric acid is 71.8 mL: 10 mL: 15 g; and / or, the mass ratio of the total mass of the hand sanitizer, glycerol and sodium lauryl sulfate to the mass ratio of the solvent B is 1:99; and / or, the ratio of the total mass of the fermented straw mixture, starch, alkali, sodium carboxymethyl cellulose, polyacrylamide to the total mass of hand soap, glycerol and dodecyl sulfuric acid is 10:1; And / or, the amounts of sodium alginate, rosin, modified polyvinyl alcohol and borax in the coal spray crust dust suppressant are 30 g / L sodium alginate, 10 g / L rosin, 5 g / L modified polyvinyl alcohol and 10 g / L borax, respectively.

3. The coal spraying type crust dust suppressant according to claim 1, characterized in that: The method for preparing the fermented straw mixture comprises the following steps: The agricultural waste is dried, ball-milled, and then soaked in water, and then ultrasonically treated. Subsequently, a microbial liquid is added for fermentation treatment. After washing, the waste is dried and ball-milled to obtain the fermented straw mixture.

4. The coal spraying type crust dust suppressant according to claim 3, characterized in that: The power of the ultrasonic treatment is 500W and the time is 30min; And / or, the fermentation temperature is 30° C. and the fermentation time is 48 hours.

5. The coal spraying type crust dust suppressant according to claim 1, characterized in that: The preparation method of the modified polyvinyl alcohol comprises the following steps: The polyvinyl alcohol and the ionic liquid are mixed and reacted to obtain the modified polyvinyl alcohol.

6. A method for preparing the coal spraying type dust suppressant according to any one of claims 1 to 5, characterized in that: The following steps are involved: The fermented straw mixture, starch and alkali are mixed evenly, and then sodium carboxymethyl cellulose and polyacrylamide are added. After mixing evenly, solvent A is added. After heating reaction, auxiliary materials and solvent B are added. After microwave-assisted blending, the coal spray-type crust dust suppressant is obtained.

7. The preparation method according to claim 6, characterized in that: The heating reaction is firstly carried out at 60-70° C. for 1-2 hours, and then at 80-90° C. for 1-2 hours.

8. The preparation method according to claim 6, characterized in that: The power of the microwave-assisted blending was 800 W, and the heating was intermittent, heating for 30 seconds, stopping for 10 seconds, and repeated 3 times.

9. Use of the coal spraying type crust suppressant according to any one of claims 1 to 5 in coal dust suppression.