A magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and controlling waste rock mountain fires, and its preparation method and application

Abstract

The present invention discloses a magnetic, temperature-sensitive dual-responsive controlled-release microcapsule material for preventing and controlling gangue mountain fires, and a preparation method and application thereof. The method mainly uses gangue flame retardant as core material, temperature-sensitive high molecular polymer as wall material, and introduces magnetic nanoparticles into the wall material to achieve controllable movement. The specific preparation method includes: mixing flame retardant, emulsifier and deionized water to obtain core material liquid; mixing temperature-sensitive high molecular polymer, nano-scale magnetic particles, emulsifier and deionized water to obtain wall material emulsion; mixing the core material liquid and the wall material emulsion, washing, filtering and drying, to obtain magnetic, temperature-sensitive dual-responsive controlled-release microcapsules. The magnetic, temperature-sensitive dual-responsive controlled-release microcapsule material for preventing and controlling gangue mountain fires prepared by the present invention can move autonomously under the action of a magnetic field, and actively release gangue flame retardant after reaching a set temperature, thereby achieving a precise fire extinguishing function.

Description

Technical Field

[0001] The invention relates to the technical field of fire prevention and extinguishing in coal mine waste rock piles, and in particular to a magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and controlling fires in waste rock piles, and a preparation method and application thereof. Background Art

[0002] The gangue produced by coal washing in coal mines has formed a huge number of gangue mountains due to long-term accumulation, with a cumulative weight of more than 5 billion tons, and it is growing rapidly at a rate of 370-550 million tons per year. Under suitable environmental conditions, spontaneous combustion occurs inside the gangue mountain, and toxic and harmful gases are emitted to pollute the environment, making it difficult to repair and manage the gangue mountain. After spontaneous combustion occurs inside the gangue mountain, the burning fire area will migrate with changes in climatic conditions, accumulation status, ventilation air volume, etc., so it is difficult to accurately locate the fire extinguishing position. The commonly used grouting fire extinguishing method requires a large amount of materials and is prone to slurry flow, while the workload of partially digging up the gangue mountain and injecting fire extinguishing materials is huge, and after the fire extinguishing materials are injected, the materials may fail and cause re-ignition.

[0003] A capsule is a container consisting of an inner core wrapped in a shell layer of a certain thickness, which can separate the internal protective material from the external environment to prevent the internal material from being destroyed. Therefore, capsule materials are gradually being widely used. At present, there is no literature report on the application of capsule materials in the field of coal mine waste rock pile fire prevention and extinguishing technology. Summary of the invention

[0004] The purpose of the present invention is to provide a magnetic and temperature-sensitive dual-responsive controlled-release microcapsule material for preventing and controlling waste rock mountain fires, and a preparation method and application thereof. The preparation method is simple and convenient, and the raw material cost is low. The prepared microcapsule material can move autonomously through the control of a magnetic field, and is applied to the prevention and control of waste rock mountain fires. When the waste rock mountain spontaneously combusts, the magnetism of the rock is stimulated to form a local magnetic field. The prepared microcapsules are driven by the magnetic field to move in a directional manner to the high-temperature fire zone. When a certain temperature is reached, the temperature-sensitive capsule wall ruptures to release the flame retardant, thereby achieving precise fire extinguishing.

[0005] To achieve the above object, the present invention is implemented by the following technical solutions:

[0006] The present invention provides a method for preparing a magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and controlling gangue mountain fires, which is characterized by comprising the following steps:

[0007] (1) Mix the gangue flame retardant, emulsifier and deionized water in a certain proportion, and mechanically stir for 30-35 minutes under heating in a water bath at 50-65° C. to form a core material liquid;

[0008] (2) mixing a thermosensitive polymer, magnetic nanoparticles, an emulsifier and deionized water in a certain proportion, and mechanically stirring the mixture in a water bath at 50-60° C. for 30-35 minutes to obtain a wall material emulsion;

[0009] (3) adding a certain amount of core material liquid dropwise to the wall material emulsion, and stirring uniformly in a water bath at 50-70° C. to prepare a mixed liquid;

[0010] (4) The mixed solution is poured into a fixed mold, and washed repeatedly with ethanol and deionized water for 3-5 times, and filtered and dried to obtain a magnetic and temperature-sensitive dual-responsive controlled-release microcapsule material for preventing and controlling waste rock mountain fires.

[0011] Furthermore, in step S1, the mass ratio of the gangue flame retardant, the emulsifier and the deionized water is 1:1:(8-10).

[0012] Furthermore, in step S2, the mass ratio of the magnetic nanoparticles, the thermosensitive high molecular polymer, the emulsifier and the deionized water is 1:(2-3):(2-3):(5-8).

[0013] Furthermore, in step S3, the mass ratio of the core material liquid to the wall material emulsion is 1:(3-5).

[0014] Furthermore, the gangue flame retardant is one or both of calcium silicate and magnesium silicate.

[0015] Furthermore, in step S2, the high molecular polymer is one of N-isopropylacrylamide, polyethylene glycol-polyacrylic acid, and poly(N-isopropylacrylamide-co-acrylic acid); the magnetic nanoparticles are one or more of iron oxide nanoparticles, cobalt magnetic nanoparticles, iron-nickel alloy nanoparticles, and neodymium iron boron alloy nanoparticles.

[0016] Furthermore, in steps S1 and S2, the emulsifier is one or more of lecithin, fish gelatin, gelatin, and sodium carboxymethyl cellulose.

[0017] Furthermore, the stirring speed is 1000-2000 rpm.

[0018] The invention also provides a magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and treating waste rock mountain fires.

[0019] The present invention also provides an application of a magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and controlling waste rock mountain fires, and the application of the microcapsule material in preventing and controlling waste rock mountain fires.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) When spontaneous combustion occurs in the waste rock pile, the rock magnetism is stimulated to form a local magnetic field. The controlled-release microcapsules prepared by the present invention move autonomously to the high-temperature fire zone through the control of the magnetic field, thereby achieving precise fire extinguishing;

[0022] (2) After the controlled-release microcapsule material prepared by the present invention reaches the high-temperature area, the temperature-sensitive wall material senses the temperature and can quickly rupture when the set temperature is exceeded, releasing the gangue flame retardant to achieve rapid fire extinguishing;

[0023] (3) The raw materials used in the present invention are low in cost and the operation process is simple and convenient; the prepared capsule wall material has high strength and stability and can cope with other complex environmental conditions in the waste rock heap. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Magnetic hysteresis regression line spectrum of the magnetic and temperature-sensitive dual-response controlled-release microcapsules prepared in Example 1;

[0025] Figure 2 This is a thermogravimetric curve of the magnetic and temperature-sensitive dual-responsive controlled-release microcapsules prepared in Example 1;

[0026] Figure 3 This is a graph of gas content during the gangue combustion process before and after the magnetic and temperature-sensitive dual-responsive controlled-release microcapsules prepared in Example 1. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] A method for preparing a magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and controlling gangue mountain fires comprises the following steps:

[0030] (1) 10 g of magnesium silicate, 10 g of sodium carboxymethyl cellulose and 80 g of deionized water were mixed in a certain proportion, and mechanically stirred for 30 min in a 50° C. water bath to form a core material liquid;

[0031] (2) 5 g of iron oxide nanoparticles, 10 g of N-isopropylacrylamide, 10 g of lecithin and 25 g of deionized water were mixed and mechanically stirred at 50° C. in a water bath for 30 min to obtain a wall material emulsion;

[0032] (3) 10 g of the core material liquid was added dropwise to 30 g of the wall material emulsion, and the mixture was stirred evenly in a 65° C. water bath to prepare a mixed solution;

[0033] (4) The mixed solution is poured into a fixed mold, washed repeatedly with ethanol and deionized water for three times, filtered and dried to obtain a magnetic and temperature-sensitive dual-responsive controlled-release microcapsule material for preventing and controlling waste rock mountain fires.

[0034] Figure 1 This is the hysteresis regression line spectrum of the magnetic and temperature-sensitive dual-responsive controlled-release microcapsules prepared in this example. It can be seen from the figure that the coercive force and remanence of the dual-responsive microcapsules are almost zero, indicating that the capsules have good superparamagnetism, and the saturation magnetization intensity is about 7.6emu·g -1 .

[0035] Figure 2 This is the thermogravimetric analysis diagram of the magnetic and temperature-sensitive dual-responsive controlled-release microcapsules prepared in this embodiment. It can be seen from the figure that the initial thermal decomposition temperature is higher than 350°C, which indicates that the microcapsules have good thermal stability and will not change their state due to environmental abnormalities, and can meet the application requirements under complex waste rock heap environmental conditions.

[0036] Figure 3 This is a graph of the gas content in the gangue combustion process before and after the magnetic and temperature-sensitive dual-responsive controlled-release microcapsules prepared in this embodiment. It can be seen from the graph that when the temperature reaches the microcapsule rupture temperature, the gangue flame retardant is rapidly released, and the CO2 and CO contents increase at a very small rate, indicating that the gangue flame retardant has good flame retardant properties and can be effectively used in gangue mountain fire prevention and control.

[0037] Example 2

[0038] A method for preparing a magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and controlling gangue mountain fires comprises the following steps:

[0039] (1) 10 g of magnesium silicate, 10 g of lecithin and 90 g of deionized water were mixed in a certain proportion, and mechanically stirred for 30 min in a 50° C. water bath to form a core material liquid;

[0040] (2) 6 g of cobalt magnetic nanoparticles, 15 g of polyethylene glycol-polyacrylic acid, 15 g of lecithin and 32 g of deionized water were mixed, and mechanically stirred for 33 min in a water bath at 50° C. to obtain a wall material emulsion;

[0041] (3) 12 g of the core material liquid was added dropwise to 40 g of the wall material emulsion, and the mixture was stirred evenly in a 65° C. water bath to prepare a mixed solution;

[0042] (4) The mixed solution is poured into a fixed mold, washed repeatedly with ethanol and deionized water for three times, filtered and dried to obtain a magnetic and temperature-sensitive dual-responsive controlled-release microcapsule material for preventing and controlling waste rock mountain fires.

[0043] Example 3

[0044] A method for preparing a magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and controlling gangue mountain fires comprises the following steps:

[0045] (1) 5 g of calcium silicate, 5 g of fish gelatin and 50 g of deionized water were mixed in a certain proportion, and mechanically stirred for 35 min in a 55° C. water bath to form a core material liquid;

[0046] (2) 3 g of iron-nickel alloy nanoparticles, 8 g of poly (N-isopropylacrylamide-co-acrylic acid), 9 g of fish gelatin and 20 g of deionized water were mixed and mechanically stirred at 55° C. in a water bath for 35 min to obtain a wall material emulsion;

[0047] (3) Add 5 g of the core material liquid dropwise to 20 g of the wall material emulsion and stir evenly in a 60°C water bath to prepare a mixed solution;

[0048] (4) The mixed solution is poured into a fixed mold, washed repeatedly with ethanol and deionized water for three times, filtered and dried to obtain a magnetic and temperature-sensitive dual-responsive controlled-release microcapsule material for preventing and controlling waste rock mountain fires.

[0049] Example 4

[0050] A method for preparing a magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and controlling gangue mountain fires comprises the following steps:

[0051] (1) 8 g of calcium silicate, 8 g of gelatin and 65 g of deionized water were mixed in a certain proportion, and mechanically stirred for 32 min in a 65° C. water bath to form a core material liquid;

[0052] (2) 10 g of NdFeB alloy nanoparticles, 25 g of N-isopropylacrylamide, 25 g of gelatin and 60 g of deionized water were mixed, and mechanically stirred for 32 min in a water bath at 60° C. to obtain a wall material emulsion;

[0053] (3) 15 g of the core material liquid was added dropwise to 75 g of the wall material emulsion, and the mixture was stirred evenly in a 65° C. water bath to prepare a mixed solution;

[0054] (4) The mixed solution is poured into a fixed mold, washed repeatedly with ethanol and deionized water for three times, filtered and dried to obtain a magnetic and temperature-sensitive dual-responsive controlled-release microcapsule material for preventing and controlling waste rock mountain fires.

[0055] The capsule materials prepared in Examples 2-4 respectively have good superparamagnetism and good thermal stability. They will not change their state with environmental abnormalities and can meet the application requirements under complex gangue mountain environmental conditions. In addition, from the gas content in the gangue combustion process before and after the dual-response controlled-release microcapsules, it can be seen that when the temperature reaches the microcapsule rupture temperature, the gangue flame retardant is rapidly released, and the CO2 and CO contents increase at a very small rate, indicating that the gangue flame retardant has good flame retardant properties and can be effectively used in gangue mountain fire prevention and control.

Claims

1. A method for preparing a magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and controlling gangue mountain fires, characterized in that: The steps include: S1. Mix the gangue flame retardant, emulsifier and deionized water in a certain proportion, and mechanically stir for 30-35 minutes under heating in a water bath at 50-65°C to form a core material liquid; the mass ratio of the gangue flame retardant, emulsifier and deionized water is 1:1:(8-10); the gangue flame retardant is one or two of calcium silicate and magnesium silicate; S2. Mix a thermosensitive polymer, magnetic nanoparticles, an emulsifier and deionized water in a certain proportion, and mechanically stir for 30-35 minutes under heating in a water bath at 50-60°C to obtain a wall material emulsion; the mass ratio of the magnetic nanoparticles, the thermosensitive polymer, the emulsifier and the deionized water is 1:(2-3):(2-3):(5-8); the thermosensitive polymer is one of N-isopropylacrylamide, polyethylene glycol-polyacrylic acid, and poly(N-isopropylacrylamide-co-acrylic acid); the magnetic nanoparticles are one or more of iron oxide nanoparticles, cobalt magnetic nanoparticles, iron-nickel alloy nanoparticles, and neodymium iron boron alloy nanoparticles; S3, adding a certain amount of core material liquid dropwise to the wall material emulsion, and stirring evenly under heating in a water bath at 50-70°C to prepare a mixed liquid; the mass ratio of the core material liquid to the wall material emulsion is 1:(3-5); S4. Pour the mixed solution into a fixed mold, wash it repeatedly with ethanol and deionized water for 3-5 times, filter and dry to obtain a magnetic and temperature-sensitive dual-responsive controlled-release microcapsule material for preventing and controlling waste rock mountain fires.

2. The method for preparing the magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and controlling fires in waste rock mountains according to claim 1, characterized in that: In steps S1 and S2, the emulsifier is one or more of lecithin, fish gelatin, gelatin, and sodium carboxymethyl cellulose.

3. A method for preparing a magnetic and temperature-sensitive dual-response controlled-release microcapsule material for preventing and controlling gangue mountain fires according to claim 1 or 2, characterized in that: The stirring speed is 1000-2000rmp.

4. A magnetic and temperature-sensitive dual-responsive controlled-release microcapsule material for preventing and controlling waste rock mountain fires prepared by the preparation method according to any one of claims 1 to 3.

5. Use of the microcapsule material prepared according to claim 4 in preventing and controlling fires in waste rock piles.

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