Environmentally friendly antifreeze dust suppressant and preparation method thereof

Abstract

The present invention belongs to the field of dust suppressants, and relates to an environmentally friendly antifreeze dust suppressant and a preparation method thereof. The present invention is an environmentally friendly antifreeze dust suppressant for open-pit coal mines, which is prepared from raw materials of 4%-10% dust-fixing agent, 0.1%-1% wetting agent, 4%-10% antifreeze agent, and the remainder being water by mass percentage. The present invention prepares a hydrogel (dust-fixing agent) with a double network structure based on the hydrogen bond interaction between molecules; based on the concept of waste utilization and green development, shells are reacted with acetic acid to prepare an environmentally friendly antifreeze agent; and finally a wetting agent is added to increase the hydrophilicity and wettability of the surface of coal dust particles. The environmentally friendly antifreeze dust suppressant of the present invention is sprayed on coal to form a layer of solidified film with strength, which can effectively bond and consolidate coal dust to prevent coal dust from being raised for the second time, thereby achieving the effect of dust suppression and dust fixing. At the same time, the present invention effectively avoids the freezing of the dust suppressant in a low temperature environment.

Description

Technical Field

[0001] The invention relates to an environmentally friendly antifreeze type dust suppressant and a preparation method thereof, belonging to the field of dust suppressants. Background Art

[0002] Coal is the most abundant and widely distributed fossil fuel on earth, accounting for 25% of the world's non-renewable energy consumption. However, while coal is mined and used, it also brings serious dust pollution problems to the surrounding environment. Sprinkling water to suppress dust is usually used in open-pit mines. It is simple to operate and low in cost, but the effective dust suppression time is short and the dust suppression efficiency is low. In the cold season in the north, the lowest temperature reaches -30℃, and sprinkling water to suppress dust will cause the road surface to freeze, which is not conducive to driving safety.

[0003] In recent years, antifreeze has been widely developed to address the problem of dust suppressants freezing easily due to low temperatures in northern winter. Most of the antifreeze agents currently on the market use chlorides such as CaCl2 and MgCl2 as their main raw materials. The advantages are good antifreeze ability, abundant raw material sources and low prices; the disadvantages are that they are corrosive to infrastructure such as steel bars and concrete, and have a certain impact on vegetation such as trees and green spaces. For this reason, we propose an environmentally friendly antifreeze dust suppressant for open-pit coal mines, which can not only improve dust suppression efficiency and dust fixation effects, but also solve the problem of dust suppressant freezing in cold winter. At the same time, the dust suppressant is environmentally friendly and degradable, will not cause environmental pollution, and is in line with the concept of green development. Summary of the invention

[0004] In view of the above problems, the present invention provides an environmentally friendly antifreeze dust suppressant and a preparation method thereof. The dust suppressant is sprayed on coal to form a strong solidified film, achieving good dust suppression and dust fixation effects and preventing secondary dust. At the same time, it will not freeze in the cold winter and has strong antifreeze ability.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] An environmentally friendly antifreeze dust suppressant is prepared from the following raw materials in percentage by mass:

[0007] Dust fixer 4%-10%, wetting agent 0.1%-1%, antifreeze 4%-10%, the balance is water;

[0008] The dust-fixing agent is formed by the reaction of polyvinyl alcohol, xanthan gum, acrylic acid and ammonium persulfate; preferably, the mass ratio of the polyvinyl alcohol, xanthan gum, acrylic acid and ammonium persulfate is 1.5:0.1:6:0.15.

[0009] The antifreeze is formed by the reaction of shells and acetic acid; preferably, the mass ratio of the shells to acetic acid is 1:3.

[0010] Furthermore, the wetting agent is selected from at least one of alkyl glycoside and sodium dodecylbenzene sulfonate.

[0011] In addition, the present invention also provides a method for preparing the above-mentioned environmentally friendly antifreeze type dust suppressant, comprising the following steps:

[0012] (1) Preparation of dust-fixing agent:

[0013] a) When the temperature is 85°C, PVA is slowly and evenly added and dispersed, and then stirred at a constant temperature for 1.5 hours. The flexible PVA molecular chains are stretched out under high temperature heating and evenly dispersed in the solution.

[0014] b) Then, at 75°C, an appropriate amount of XG was slowly and evenly added and dispersed into the above solution, and stirred at a constant temperature for 1.5 hours. During this process, the flexible polymer chain (PVA) diffused into the structured polymer (XG), and a large number of -OH groups in the chemical structures of the two interacted with each other by hydrogen bonds to form the first layer of network structure.

[0015] c) The temperature is reduced to 55°C, and under nitrogen protection, AA and NaOH with a neutralization degree of 70% are added. After 10 minutes, ammonium persulfate (APS) is added as an initiator. After about 1 hour, the reaction is completed to obtain PVA-XG-PAA. During this process, the AA added to the solution will be evenly dispersed in the first layer of the network structure. The APS added subsequently decomposes free radicals under heating, which can induce the polymerization reaction of AA to form polyacrylic acid chains. The polyacrylic acid chain continues to grow during the reaction, gradually penetrating the first layer of the network structure, and the -COOH on it interacts with the -OH on PVA and XG through hydrogen bonds to form a second layer of the network structure, thereby obtaining a hydrogel with a double network structure.

[0016] d) finally drying and grinding into white powder to obtain a dust-fixing agent;

[0017] (2) Preparation of antifreeze:

[0018] (a) The shells are first rinsed with clean water to remove the pigment layer and soluble organic matter on the shell surface; dried, crushed and dried at 110°C to remove water, and the off-white shell powder is used for later use;

[0019] (b) heating acetic acid to 60° C., gradually adding shell powder while stirring, and continuing to add shell powder until bubbles are generated, until the shell powder no longer decomposes after adding a small amount of shell powder, continuing to stir at constant temperature for 30 minutes, filtering to remove insoluble matter, and obtaining a clear calcium acetate solution;

[0020] (c) heating the calcium acetate solution to evaporate and concentrate, and when solid precipitates in the solution, cooling the solution to rapidly solidify the solution to obtain a white block of calcium acetate, drying and dehydrating the solution in a drying oven at 120° C. for 30 min, and crushing the solution to obtain a white powdery antifreeze;

[0021] (3) Preparation of environmentally friendly antifreeze dust suppressant:

[0022] Mix the dust-fixing agent, wetting agent, antifreeze agent and water, and stir at a constant temperature for 30 minutes to obtain an environmentally friendly antifreeze dust suppressant.

[0023] The method of using the invention is spraying, and the amount of the dust suppressant used is 0.3-0.5 kg / m2.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The dust-fixing agent of the present invention is a hydrogel with a double network structure. The double network hydrogel is formed by the interpenetration and cross-linking of a rigid network and a flexible network. It not only has high viscoelasticity and good water retention, but also the double network structure ensures the mechanical strength and good tensile properties of the hydrogel, breaking through the shortcomings of poor mechanical properties of traditional single network hydrogels. The tensile strength and compressive strength can both reach the order of megapascals, which is incomparable to single network hydrogels. In addition, the double network hydrogel also has the advantages of biocompatibility and green environmental protection. Polyvinyl alcohol, xanthan gum, and acrylic acid contain abundant hydroxyl and carboxyl groups, which can electrostatically interact with the N-containing functional groups in coal and hydrogen bond with the O-containing functional groups in coal. Therefore, the dust-fixing agent can well bond and consolidate the coal dust and enhance the agglomeration effect. As the outside air absorbs heat, the moisture attached to the surface of the coal dust gradually evaporates, thereby continuously reducing the moisture content. The dust-fixing agent finally forms a hard solidified layer that can retain a certain amount of moisture, prevent the solidified layer from cracking after drying, reduce the moisture evaporation rate, and enhance the dust suppression effect; at the same time, the raw materials of the dust-fixing agent are widely available, environmentally friendly, and pollution-free to the environment;

[0026] Antifreeze is made by the reaction of CaCO3 in shells and acetic acid. It has strong anti-freeze ability and has basically no corrosion to metal and concrete materials. It also prevents the dust suppressant from freezing even in the cold winter. It also complies with the concept of waste utilization and environmental protection and green development.

[0027] The wetting agent can increase the hydrophilicity and wettability of the surface of the coal dust particles, so that the dust suppressant can penetrate well into the gaps between the coal dust particles and fill the gaps between the coal dust particles;

[0028] The environmentally friendly antifreeze dust suppressant of the present invention has moderate viscosity and can be well sprayed on coal through a nozzle to form a strong solidified film, effectively bonding and consolidating the coal dust, and having excellent water retention performance to prevent the coal dust from being raised again; it can penetrate into the gaps between coal dust particles and fill the gaps between coal dust particles; and the present invention will not freeze in cold weather. The raw materials of the environmentally friendly antifreeze dust suppressant of the present invention are all environmentally friendly materials, green and degradable, and have no pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1The viscosity test results of different groups of dust suppressants are shown;

[0030] Figure 2 The test results of wind erosion resistance of different groups of dust suppressants;

[0031] Figure 3 The test results of water retention rate of different groups of dust suppressants;

[0032] Figure 4 The antifreeze test results of different groups of dust suppressants are shown;

[0033] Figure 5 These are the compressive strength test results of different groups of dust suppressants. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, the embodiments are exemplary only and do not constitute any limitation to the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solution of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the scope of protection of the present invention.

[0035] Example 1 An environmentally friendly antifreeze dust suppressant and its preparation method

[0036] The environmentally friendly antifreeze dust suppressant is a mixed aqueous solution composed of the following components in percentage by mass:

[0037] Dust-fixing agent: polyvinyl alcohol 0.78%, xanthan gum 0.052%, acrylic acid 3.12%, ammonium persulfate 0.078%;

[0038] Wetting agent: 0.1% alkyl glycoside;

[0039] Antifreeze: 1% shell powder, 3% acetic acid;

[0040] The balance is water.

[0041] The preparation method of the environmentally friendly antifreeze dust suppressant comprises the following steps:

[0042] (1) Preparation of dust-fixing agent: In a water bath at 85°C, slowly and evenly add and disperse PVA, and then stir at a constant temperature for 1.5 hours; then adjust the water bath temperature to 75°C, slowly and evenly add and disperse XG, and stir at a constant temperature for 1.5 hours; finally, lower the water bath temperature to 55°C, add AA under nitrogen protection, and add APS as an initiator after 10 minutes. After about 1 hour, a reaction product is obtained; dry and grind into a white powder to obtain a dust-fixing agent;

[0043] (2) Preparation of antifreeze:

[0044] (a) Rinse the shells with clean water to remove the pigment layer and a small amount of soluble organic matter on the shell surface. Dry them, crush them and dry them at 110℃ for 1 hour to remove water; the off-white shell powder is used for later use;

[0045] (b) heating acetic acid to 60° C., gradually adding shell powder while stirring, and continuing to add shell powder until bubbles are generated, until the shell powder no longer decomposes after adding a small amount of shell powder, continuing to stir at constant temperature for 30 minutes, filtering to remove insoluble matter, and obtaining a clear calcium acetate solution;

[0046] (c) heating the calcium acetate solution to evaporate and concentrate, and when a small amount of solid precipitates out of the solution, cooling the solution, causing the solution to solidify rapidly to obtain a white block of calcium acetate, which is placed in a drying oven at 110 to 130° C. for drying and dehydration for 30 min, and then crushed to obtain a white powdery antifreeze agent;

[0047] (3) Preparation of environmentally friendly antifreeze dust suppressant: Mix dust fixer, wetting agent, antifreeze agent and water, stir at constant temperature for 30 minutes, and obtain the finished product.

[0048] Example 2 An environmentally friendly antifreeze dust suppressant and its preparation method

[0049] The environmentally friendly antifreeze dust suppressant is a mixed aqueous solution composed of the following components in percentage by mass:

[0050] Dust-fixing agent: polyvinyl alcohol 1.94%, xanthan gum 0.13%, acrylic acid 7.74%, ammonium persulfate 0.194%;

[0051] Wetting agent: sodium dodecylbenzene sulfonate 1%;

[0052] Antifreeze: 1% shell powder, 3% acetic acid;

[0053] The balance is water.

[0054] The preparation method of the environmentally friendly antifreeze dust suppressant comprises the following steps:

[0055] (1) Preparation of dust-fixing agent: In a water bath at 85°C, slowly and evenly add and disperse PVA, and then stir at a constant temperature for 1.5 hours; then adjust the water bath temperature to 75°C, slowly and evenly add and disperse XG, and stir at a constant temperature for 1.5 hours; finally, lower the water bath temperature to 55°C, add AA under nitrogen protection, and add APS as an initiator after 10 minutes. After about 1 hour, a reaction product is obtained; dry and grind into a white powder to obtain a dust-fixing agent;

[0056] (2) Preparation of antifreeze:

[0057] (a) Rinse the shells with clean water to remove the pigment layer and a small amount of soluble organic matter on the shell surface. Dry them, crush them and dry them at 110℃ for 1 hour to remove water; the off-white shell powder is used for later use;

[0058] (b) heating acetic acid to 60° C., gradually adding shell powder while stirring, and continuing to add shell powder until bubbles are generated, until the shell powder no longer decomposes after adding a small amount of shell powder, continuing to stir at constant temperature for 30 minutes, filtering to remove insoluble matter, and obtaining a clear calcium acetate solution;

[0059] (c) heating the calcium acetate solution to evaporate and concentrate, and when a small amount of solid precipitates out of the solution, cooling the solution, causing the solution to solidify rapidly to obtain a white block of calcium acetate, which is placed in a drying oven at 110° C. for drying and dehydration for 30 min, and then crushed to obtain a white powdery antifreeze;

[0060] (3) Preparation of environmentally friendly antifreeze dust suppressant: Mix dust fixation agent, wetting agent, antifreeze agent and part of water, stir at constant temperature for 30 minutes, and obtain the finished product.

[0061] Example 3 An environmentally friendly antifreeze dust suppressant and its preparation method

[0062] The environmentally friendly antifreeze dust suppressant is a mixed aqueous solution composed of the following components in percentage by mass:

[0063] Dust-fixing agent: polyvinyl alcohol 0.78%, xanthan gum 0.052%, acrylic acid 3.12%, ammonium persulfate 0.078%;

[0064] Wetting agent: 0.1% alkyl glycoside, 0.1% sodium dodecylbenzene sulfonate;

[0065] Antifreeze: 1% shell powder, 3% acetic acid;

[0066] The balance is water.

[0067] The preparation method of the environmentally friendly antifreeze dust suppressant comprises the following steps:

[0068] (1) Preparation of dust-fixing agent: In a water bath at 85°C, slowly and evenly add and disperse PVA, and then stir at a constant temperature for 1.5 hours; then adjust the water bath temperature to 75°C, slowly and evenly add and disperse XG, and stir at a constant temperature for 1.5 hours; finally, lower the water bath temperature to 55°C, add AA under nitrogen protection, and add APS as an initiator after 10 minutes. After about 1 hour, a reaction product is obtained; dry and grind into a white powder to obtain a dust-fixing agent;

[0069] (2) Preparation of antifreeze:

[0070] (a) Rinse the shells with clean water to remove the pigment layer and a small amount of soluble organic matter on the shell surface. Dry them, crush them and dry them at 110℃ for 1 hour to remove water; the off-white shell powder is used for later use;

[0071] (b) heating acetic acid to 60° C., gradually adding shell powder while stirring, and continuing to add shell powder until bubbles are generated, until the shell powder no longer decomposes after adding a small amount of shell powder, continuing to stir at constant temperature for 30 minutes, filtering to remove insoluble matter, and obtaining a clear calcium acetate solution;

[0072] (c) transferring the prepared clear calcium acetate solution into an evaporating dish, heating and evaporating the solution to concentrate the solution, cooling the solution to rapidly solidify the solution to obtain a white block of calcium acetate, placing the solution in a drying oven at 110-130° C. for drying and dehydration for 30 min, and crushing the solution to obtain a white powdery antifreeze agent;

[0073] (3) Preparation of environmentally friendly antifreeze dust suppressant: Mix dust fixation agent, wetting agent, antifreeze agent and part of water, stir at constant temperature for 30 minutes, and obtain the finished product.

[0074] Comparative Example 1: (without polyvinyl alcohol) antifreeze dust suppressant

[0075] The mixed aqueous solution is composed of the following components in percentage by mass:

[0076] Dust-fixing agent: xanthan gum 0.052%, acrylic acid 3.12%, ammonium persulfate 0.078%;

[0077] Wetting agent: 0.1% alkyl glycoside;

[0078] Antifreeze: 1% shell powder and 3% acetic acid.

[0079] The preparation method is the same as Example 1.

[0080] Comparative Example 2: (without acrylic acid) antifreeze dust suppressant

[0081] The mixed aqueous solution is composed of the following components in percentage by mass:

[0082] Dust-fixing agent: polyvinyl alcohol 0.78%, xanthan gum 0.052%, ammonium persulfate 0.078%;

[0083] Wetting agent: 0.1% alkyl glycoside;

[0084] Antifreeze: 1% shell powder and 3% acetic acid.

[0085] The preparation method is the same as Example 1.

[0086] Comparative Example 3: (without wetting agent) antifreeze dust suppressant

[0087] The mixed aqueous solution is composed of the following components in percentage by mass:

[0088] Dust-fixing agent: polyvinyl alcohol 0.78%, xanthan gum 0.052%, acrylic acid 3.12%, ammonium persulfate 0.078%;

[0089] Antifreeze: 1% shell powder and 3% acetic acid.

[0090] The preparation method is the same as Example 1.

[0091] Comparative Example 4: (without antifreeze) dust suppressant

[0092] The mixed aqueous solution is composed of the following components in percentage by mass:

[0093] Dust-fixing agent: polyvinyl alcohol 0.78%, xanthan gum 0.052%, acrylic acid 3.12%, ammonium persulfate 0.078%;

[0094] Wetting agent: 0.1% alkyl glycoside;

[0095] The preparation method is the same as Example 1.

[0096] Performance testing of dust suppressants

[0097] The dust suppressants prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests, mainly testing their wind erosion resistance, water retention, compressive strength and antifreeze properties. The test results are shown in Table 1. Figure 1-5 .

[0098] Table 1 Performance test comparison table of dust suppressants

[0099]

[0100] As can be seen from Table 1, the environmentally friendly antifreeze dust suppressants obtained in Examples 1, 2 and 3 of the present invention all have wind erosion resistance of more than 95%, moisture retention rates of more than 90%, and have good dust suppression and dust fixation effects.

[0101] from Figure 1 It can be seen that Example 2 has the highest viscosity (42.74), while Comparative Example 2 has the lowest viscosity (21.56). The acrylic acid content in Example 2 is the highest, while no acrylic acid is added in Comparative Example 2. Therefore, it can be inferred that acrylic acid is the main factor affecting the viscosity of the environmentally friendly antifreeze dust suppressant of the invention.

[0102] from Figure 2 and Figure 5 It can be seen that the viscosity, wind erosion resistance and compressive strength of Comparative Examples 1 and 2 are the lowest. The reason is that no polyvinyl alcohol is added in Comparative Example 1, and no acrylic acid is added in Comparative Example 2. Finally, only a single-network hydrogel (dust-fixing agent) can be formed. The single-network hydrogel has problems such as poor mechanical properties and uneven network structure. It will break under lower stress or strain. Therefore, the shell formed after interaction with coal dust is easily destroyed, and the dust-fixing effect is poor.

[0103] from Figure 3 It can be seen that the water retention rate of comparative example 3 is the lowest. The reason is that no wetting agent is added in comparative example 3, and the dust suppressant cannot wet the surface of the coal dust well, and cannot penetrate the coal dust well to fill the gaps between the coal dust particles. Therefore, after spraying for a period of time, the water evaporates quickly.

[0104] from Figure 4 It can be seen that the antifreeze property of Comparative Example 4 is the worst. The reason is that no antifreeze agent is added in Comparative Example 4, so the dust suppressant cannot withstand a lower temperature.

[0105] To sum up, only the environmentally friendly antifreeze dust suppressant prepared by mixing the dust fixer, antifreeze agent and wetting agent prepared by polyvinyl alcohol, xanthan gum and acrylic acid can have excellent water retention, wind erosion resistance, antifreeze and compressive strength at the same time, and can withstand low temperatures without freezing in the cold winter in the north, and maintain good dust suppression and dust fixation performance.

[0106] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An environmentally friendly antifreeze dust suppressant, characterized in that: The environmentally friendly antifreeze dust suppressant is prepared from the following raw materials in percentage by mass: 4%-10% dust fixer, 0.1%-1% wetting agent, 4%-10% antifreeze agent, and the balance is water; the dust fixer is formed by the reaction of polyvinyl alcohol, xanthan gum, acrylic acid and ammonium persulfate; The mass ratio of the polyvinyl alcohol, xanthan gum, acrylic acid and ammonium persulfate is 1.5:0.1:6:0.15; The antifreeze agent is formed by the reaction of shells and acetic acid; the mass ratio of the shells to the acetic acid is 1:3; The method for preparing the environmentally friendly antifreeze dust suppressant comprises the following steps: (1) Preparation of dust-fixing agent a) When the temperature is 85°C, PVA is slowly and evenly added and dispersed, and then stirred at constant temperature for 1.5 hours. The flexible PVA molecular chains are stretched out under high temperature heating and evenly dispersed in the solution; b) slowly and evenly adding and dispersing XG into the solution of step a) at 75° C. and stirring at constant temperature for 1.5 h; c) The temperature was lowered to 55°C, and under nitrogen protection, AA and NaOH with a neutralization degree of 70% were added. After 10 minutes, ammonium persulfate (APS) was added as an initiator. After 1 hour, the reaction was completed to obtain PVA-XG-PAA; d) finally drying and grinding into white powder to obtain a dust-fixing agent; (2) Preparation of antifreeze: (a) The shells are first rinsed with clean water to remove the pigment layer and soluble organic matter on the shell surface; dried, crushed and dried at 110°C to remove water, and the off-white shell powder is used for later use; (b) heating acetic acid to 60° C., gradually adding shell powder while stirring, and continuing to add shell powder until bubbles are generated, until the shell powder no longer decomposes after adding a small amount of shell powder, continuing to stir at constant temperature for 30 minutes, filtering to remove insoluble matter, and obtaining a clear calcium acetate solution; (c) heating the calcium acetate solution to evaporate and concentrate, and when solid precipitates in the solution, cooling the solution to rapidly solidify the solution to obtain a white block of calcium acetate, drying and dehydrating the solution in a drying oven at 120° C. for 30 min, and crushing the solution to obtain a white powdery antifreeze; (3) Preparation of environmentally friendly antifreeze dust suppressant: Mix the dust-fixing agent, wetting agent, antifreeze agent and water, and stir at a constant temperature for 30 minutes to obtain the environmentally friendly antifreeze dust suppressant.

2. The environmentally friendly antifreeze dust suppressant according to claim 1, characterized in that: The wetting agent is selected from at least one of alkyl glycoside and sodium dodecylbenzene sulfonate.

3. The environmentally friendly antifreeze dust suppressant as claimed in claim 1 or 2, which is used by spraying.

4. The environmentally friendly antifreeze dust suppressant as claimed in claim 1 or 2, wherein the dosage is 0.3-0.5 kg / m2.

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