Special dust faller in tunnel construction environment and preparation method thereof

Abstract

The application discloses a special dust-settling agent under a tunnel construction environment and a preparation method thereof. The application relates to the field of dust-settling agent preparation under a tunnel construction environment, and solves the problems of high preparation cost, difficulty in large-scale production and limited dust-settling performance of the existing dust-settling agent preparation method. In the application, polyvinyl alcohol, guar gum and itaconic acid are subjected to graft copolymerization reaction under nitrogen protection at 60 DEG C-70 DEG C, N,N'-methylene bisacrylamide crosslinking agent is added to form a chemical crosslinking network, and then the chemical crosslinking network is compounded with a surfactant to obtain the dust-settling agent. The dust-settling agent does not need low-temperature freezing and thawing treatment, can significantly reduce equipment energy consumption and production cost, is convenient for industrialized production, has good film-forming property, moderate viscosity and long water-retention duration, and can efficiently inhibit diffusion of dust generated in tunnel construction.

Description

Technical Field

[0001] This invention relates to the field of dust suppressant preparation technology for tunnel construction environments, and particularly to a special dust suppressant for tunnel construction environments and its preparation method. Background Technology

[0002] Dust pollution generated during tunnel construction is a long-standing and urgent problem. During drilling and blasting or shield tunneling methods, processes such as rock crushing, spoil loading and unloading, and transportation generate large amounts of high-concentration mineral dust. This dust has a fine particle size and strong diffusion properties, seriously threatening the respiratory health of on-site construction workers, reducing equipment operating efficiency, and even posing safety hazards. To address this issue, the industry commonly uses dust suppressants to inhibit dust dispersion. Among various dust suppressant materials, bio-polysaccharide dust suppressants, represented by guar gum, are widely used due to their green, environmentally friendly, and biodegradable characteristics.

[0003] However, in existing technologies, to improve the mechanical properties and water retention of such dust suppressants, it is usually necessary to construct a stable three-dimensional network structure using physical cross-linking methods such as cryogenic freezing and thawing. While this method can achieve certain results under laboratory conditions, its preparation process is highly dependent on cryogenic equipment. This not only leads to high equipment costs and huge energy consumption but also greatly limits the efficiency of large-scale production of dust suppressants, making it difficult to meet the large-scale, immediate demand for dust suppressants at tunnel construction sites. Furthermore, hydrogels formed solely through physical cross-linking often suffer from poor solubility, poor flowability, and difficulty in quickly forming a uniform covering film on dust surfaces in practical applications, thus affecting the effectiveness and durability of dust suppression.

[0004] Therefore, it is necessary to propose a special dust suppressant for tunnel construction environments and its preparation method to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a special dust suppressant for tunnel construction environments and its preparation method, so as to solve the problems of high preparation cost, difficulty in large-scale production and limited dust suppression performance of existing dust suppressant preparation methods.

[0006] In a first aspect, the present invention provides a special dust suppressant for tunnel construction environments, comprising the following raw materials in parts by weight: Guar gum 0.1-1 part; Polyvinyl alcohol 0.1-1 part; Itaconic acid 0.5-5 parts; Sodium hydroxide 0.3-1.5 parts; Potassium persulfate 0.01-0.15 parts; 0.0001-0.005 parts of N,N'-methylenebisacrylamide; Surfactant 0.0001-0.0005 parts; 250-270 parts of deionized water.

[0007] Furthermore, the surfactant is any one or more of fatty alcohol polyoxyethylene ether, alkyl glycoside, and sodium dodecyl sulfate.

[0008] Secondly, the present invention provides a method for preparing a special dust suppressant for tunnel construction environments, comprising: Step 1: Provide the following raw materials in parts by weight: 0.1-1 parts guar gum, 0.1-1 parts polyvinyl alcohol, 0.5-5 parts itaconic acid, 0.3-1.5 parts sodium hydroxide, 0.01-0.15 parts potassium persulfate, 0.0001-0.005 parts N,N'-methylenebisacrylamide, 0.0001-0.0005 parts surfactant, and 250-270 parts deionized water; Add polyvinyl alcohol and deionized water to a beaker, heat in a water bath to 90°C and stir for 1 hour, then cool to 65°C to obtain mixture one; Step 2: Add guar gum to a beaker, stir to dissolve, add to mixture 1, stir evenly to obtain mixture 2; Step 3: Add sodium hydroxide to itaconic acid and mix thoroughly until the neutralization degree reaches 70%-80%, to obtain mixture 3; Step four: Add the mixture three drops to the mixture two, then add N,N'-methylenebisacrylamide, and stir for 20-30 minutes under nitrogen protection to obtain mixture four; Step 5: Add potassium persulfate to mixture 4 and react under nitrogen protection for 2-4 hours at a reaction temperature of 60-70°C to obtain mixture 5. Step six: After cooling the mixture, add the surfactant and mix evenly to obtain a special dust suppressant for tunnel construction environments.

[0009] Furthermore, in step one, the surfactant is any one or more of fatty alcohol polyoxyethylene ether, alkyl glycoside, and sodium dodecyl sulfate.

[0010] Furthermore, in step one, the stirring rate is 400 rpm to 600 rpm.

[0011] Furthermore, in step five, the reaction temperature is 60℃-70℃.

[0012] The beneficial effects of this invention are as follows: By chemically grafting and copolymerizing guar gum, polyvinyl alcohol, and itaconic acid, this invention further enhances the adsorption and agglomeration of dust particles and exhibits excellent water retention properties. The film-forming properties of polyvinyl alcohol and the cross-linking ability of the dicarboxyl groups in itaconic acid are organically combined, giving the dust suppressant of this invention excellent film-forming performance. After spraying, the dust suppressant can form a dense, continuous polymer film on the dust surface, effectively binding dust particles and inhibiting their diffusion, forming a dense and durable cured film. Furthermore, itaconic acid has advantages such as being non-toxic, environmentally friendly, and biodegradable, and will not remain in the environment for a long time after spraying, avoiding secondary environmental pollution. In summary, this invention achieves a synergistic effect of multiple functions such as film formation, agglomeration, and water retention through graft copolymerization of guar gum, polyvinyl alcohol, and itaconic acid. The synthesized dust suppressant raw materials are green, environmentally friendly, and biodegradable, suitable for spraying in tunnel construction environments, and improving work efficiency. This invention requires no cryogenic freezing equipment; the polymerization reaction can be completed under conventional heating conditions of around 60℃-70℃. The reaction cycle is short (several hours), and the equipment investment and energy consumption are significantly lower than those of the freeze-thaw method, making it possible for the large-scale, low-cost application of dust suppressants as bulk consumables. Excellent film-forming properties and hardness: This invention forms a stable covalent network through MBA chemical crosslinking, resulting in a dust suppressant with excellent film-forming properties, capable of forming a dense and durable cured film with adjustable and high hardness. Designable and durable water retention performance: The dust suppressant prepared by this invention exhibits regular and excellent staged water retention performance, demonstrating long-lasting dust suppressing capabilities. Attached Figure Description

[0013] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0014] Figure 1 This is a flowchart illustrating the preparation method of the special dust suppressant for tunnel construction environments according to the present invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. The technical solutions provided by various embodiments of this invention will be described in detail below with reference to the accompanying drawings.

[0016] Please see Figure 1This invention uses deionized water as a solvent, guar gum and polyvinyl alcohol as the backbone, itaconic acid as the monomer, potassium persulfate as the initiator, and N,N'-methylenebisacrylamide as the crosslinking agent to synthesize a product and compound it with a surfactant to obtain a special dust suppressant for tunnel construction environments. This invention focuses on the synthesis of a special dust suppressant for tunnel construction environments. Based on the biopolysaccharide guar gum and polyvinyl alcohol with excellent film-forming properties, this invention chemically modifies them to obtain a dust suppressant with moderate viscosity, good moisturizing effect, good film-forming properties, and is non-toxic and biodegradable.

[0017] This application provides a special dust suppressant for tunnel construction environments. The special dust suppressant comprises the following raw materials in parts by weight: 0.1-1 parts guar gum; 0.1-1 parts polyvinyl alcohol; 0.5-5 parts itaconic acid; 0.3-1.5 parts sodium hydroxide; 0.01-0.15 parts potassium persulfate; 0.0001-0.005 parts N,N'-methylenebisacrylamide; 0.0001-0.0005 parts surfactant; and 250-270 parts deionized water.

[0018] Example 1: The dust suppressant for tunnel construction environments in this embodiment comprises, by weight, 0.5 parts guar gum; 0.5 parts polyvinyl alcohol; 2 parts itaconic acid; 0.98 parts sodium hydroxide; 0.06 parts potassium persulfate; 0.001 parts N,N'-methylenebisacrylamide; 0.0001 parts surfactant; and 250 parts deionized water.

[0019] In this embodiment, a method for preparing a special dust suppressant for tunnel construction environments includes the following steps: Step 1: Add polyvinyl alcohol and deionized water to a beaker, heat in a water bath to 90°C and stir for 1 hour, then cool to 65°C to obtain mixture 1.

[0020] Specifically, the stirring rate is 400 rpm.

[0021] Step 2: Add guar gum to a beaker, stir to dissolve, add to mixture 1, stir well to obtain mixture 2.

[0022] Step 3: Slowly add sodium hydroxide to itaconic acid and mix thoroughly until the degree of neutralization reaches 80%, resulting in mixture 3.

[0023] Step four: Slowly add mixture three to mixture two, then add N,N'-methylenebisacrylamide, and stir for 20 minutes under nitrogen protection to obtain mixture four.

[0024] Step 5: Add potassium persulfate to mixture 4 and react under nitrogen protection for 2.5 h to obtain mixture 5.

[0025] Specifically, the reaction temperature is 65°C.

[0026] Step six: Cool the mixture to room temperature, add the surfactant, mix well, and obtain a special dust suppressant for tunnel construction environments.

[0027] Example 2: The dust suppressant for tunnel construction environments in this embodiment comprises, by weight, 0.6 parts guar gum; 0.4 parts polyvinyl alcohol; 3 parts itaconic acid; 1.48 parts sodium hydroxide; 0.06 parts potassium persulfate; 0.0015 parts N,N'-methylenebisacrylamide; 0.0002 parts surfactant; and 250 parts deionized water.

[0028] In this embodiment, a method for preparing a special dust suppressant for tunnel construction environments includes the following steps: Step 1: Add polyvinyl alcohol and deionized water to a beaker, heat in a water bath at 90°C and stir for 1 hour, then cool to 65°C to obtain mixture 1.

[0029] Specifically, the stirring speed is 500 rpm. Step 2: Add guar gum to a beaker, stir to dissolve, add to mixture 1, stir well to obtain mixture 2.

[0030] Step 3: Slowly add sodium hydroxide to itaconic acid and mix thoroughly until the degree of neutralization reaches 80%, resulting in mixture 3.

[0031] Step four: Slowly add mixture three to mixture two, then add N,N'-methylenebisacrylamide, and stir for 30 minutes under nitrogen protection to obtain mixture four.

[0032] Step 5: Add potassium persulfate to mixture 4 and react under nitrogen protection for 2.5 h to obtain mixture 5.

[0033] Specifically, the reaction temperature is 65°C.

[0034] Step six: Cool the mixture to room temperature, add the surfactant, mix well, and obtain a special dust suppressant for tunnel construction environments.

[0035] Example 3: The dust suppressant for tunnel construction environments in this embodiment comprises, by weight, 0.4 parts guar gum; 0.6 parts polyvinyl alcohol; 1 part itaconic acid; 0.49 parts sodium hydroxide; 0.01 parts potassium persulfate; 0.0005 parts N,N'-methylenebisacrylamide; 0.0004 parts surfactant; and 250 parts deionized water.

[0036] In this embodiment, a method for preparing a special dust suppressant for tunnel construction environments includes the following steps: Step 1: Add polyvinyl alcohol and deionized water to a beaker, heat in a water bath at 90°C and stir for 1 hour, then cool to 65°C to obtain mixture 1.

[0037] Specifically, the stirring speed is 450 rpm. Step 2: Add guar gum to a beaker, stir to dissolve, add to mixture 1, stir well to obtain mixture 2.

[0038] Step 3: Slowly add sodium hydroxide to itaconic acid and mix thoroughly until the degree of neutralization reaches 80%, resulting in mixture 3.

[0039] Step four: Slowly add mixture three to mixture two, then add N,N'-methylenebisacrylamide, and stir for 25 minutes under nitrogen protection to obtain mixture four.

[0040] Step 5: Add potassium persulfate to mixture 4 and react under nitrogen protection for 2.5 h to obtain mixture 5.

[0041] Specifically, the reaction temperature is 65°C.

[0042] Step six: Cool the mixture to room temperature, add the surfactant, mix well, and obtain a special dust suppressant for tunnel construction environments.

[0043] The water retention capacity of the special dust suppressant for tunnel construction environments prepared according to this invention was tested. Coal powder sprayed with the dust suppressant was placed indoors, and its water retention rate was tested. The coal powder was dried in a 50°C vacuum drying oven. The initial mass W0 of the sample and petri dish was weighed, and the mass of the sprayed dust suppressant was recorded as W1. The sample mass was recorded at intervals, recorded as W2, for a total recording time of 24 hours. The water retention rate within 24 hours was obtained using the following formula: W b =1— (1) In equation (1), W b W0 represents the sample moisture content (%); W1 represents the mass of the sample and petri dish (g); W2 represents the mass of the sample after the required interval (g). The results of the water retention test are shown in Table 1 below.

[0044] Table 1. Results of water retention test The viscosity and hardness of the special dust suppressant for tunnel construction environments prepared according to this invention were tested. The viscosity of the dust suppressant solution in the example was tested using a digital viscometer. An appropriate amount of sieved (200 mesh) coal powder was weighed, poured into a 6cm petri dish, and compacted by vibration at a rate of 2L / m³. 2Equal volumes of the dust suppressant solution from the example were sprayed onto the dust surface and allowed to air dry at room temperature. The hardness of the coal dust was then measured using an LXD-A type hardness tester. The viscosity and hardness test results are shown in Table 2 below.

[0045] Table 2 Viscosity and Hardness Test Results Based on the test data of water retention, viscosity, and hardness, the dust suppressant for tunnel construction of this invention has a simple preparation process and is easy to operate. Upon initial spraying, the dust suppressant forms a uniform wet layer on the dust surface, exhibiting good initial water retention and quickly locking in moisture to effectively suppress dust. Furthermore, the water retention rate remains above 78% after 8 hours of spraying and still reaches above 36% after 24 hours, demonstrating excellent sustained water retention capacity. Simultaneously, the viscosity design of this dust suppressant is reasonable, ensuring both fluidity and atomization uniformity during spraying while avoiding nozzle clogging due to excessive viscosity or excessive runoff due to excessively low viscosity. Hardness test results show that the hard shell layer formed after drying and curing of the dust suppressant has suitable mechanical strength, effectively resisting airflow disturbances and slight rolling, meeting the durability requirements of the dust suppression layer in the tunnel construction environment. In summary, this invention achieves efficient and long-lasting dust suppression while ensuring good construction performance.

[0046] The embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention.

Claims

1. A special dust suppressant for use in tunnel construction environments, characterized in that, Including the following parts by weight of raw materials: Guar gum 0.1-1 part; Polyvinyl alcohol 0.1-1 part; Itaconic acid 0.5-5 parts; Sodium hydroxide 0.3-1.5 parts; Potassium persulfate 0.01-0.15 parts; 0.0001-0.005 parts of N,N'-methylenebisacrylamide; Surfactant 0.0001-0.0005 parts; 250-270 parts of deionized water.

2. The special dust suppressant for tunnel construction environments according to claim 1, characterized in that, The surfactant is any one or more of fatty alcohol polyoxyethylene ether, alkyl glycoside, and sodium dodecyl sulfate.

3. A method for preparing a special dust suppressant for tunnel construction environments, characterized in that, include: Step 1: Provide the following raw materials in parts by weight: 0.1-1 parts guar gum, 0.1-1 parts polyvinyl alcohol, 0.5-5 parts itaconic acid, 0.3-1.5 parts sodium hydroxide, 0.01-0.15 parts potassium persulfate, 0.0001-0.005 parts N,N'-methylenebisacrylamide, 0.0001-0.0005 parts surfactant, and 250-270 parts deionized water; Add polyvinyl alcohol and deionized water to a beaker, heat in a water bath to 90°C and stir for 1 hour, then cool to 65°C to obtain mixture one; Step 2: Add guar gum to a beaker, stir to dissolve, add to mixture 1, stir evenly to obtain mixture 2; Step 3: Add sodium hydroxide to itaconic acid and mix thoroughly until the degree of neutralization reaches 70%-80%, to obtain mixture 3; Step four: Add the mixture three drops to the mixture two, then add N,N'-methylenebisacrylamide, and stir for 20-30 minutes under nitrogen protection to obtain mixture four; Step 5: Add potassium persulfate to mixture 4 and react under nitrogen protection for 2-4 hours at a reaction temperature of 60-70°C to obtain mixture 5. Step six: After cooling the mixture, add the surfactant and mix evenly to obtain a special dust suppressant for tunnel construction environments.

4. The method for preparing a special dust suppressant for tunnel construction environments according to claim 3, characterized in that, In step one, the surfactant is any one or more of fatty alcohol polyoxyethylene ether, alkyl glycoside, and sodium dodecyl sulfate.

5. The method for preparing a special dust suppressant for tunnel construction environments according to claim 3, characterized in that, In step one, the stirring speed is 400 rpm to 600 rpm.

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