An explosive with a strong acid suppression coating structure and its preparation method

Abstract

The present invention discloses an explosive with a strong acid-inhibiting coating structure and a preparation method thereof. The nano-Fe₂O₃ powder is dispersed in a hot solvent to form a uniform dispersion liquid, which is added to a supersaturated explosive suspension, stirred evenly to obtain a mixed slurry. Then, through a spray drying process, nitrogen is passed through for fine granulation, and finally, after washing and drying, an explosive with a strong acid-inhibiting coating structure is prepared. At the same time, the present invention also discloses an explosive with a strong acid-inhibiting coating structure, which realizes comprehensive functions such as acid inhibition, desensitization, and heat conduction through the coating structure prepared on the surface of the explosive, and solves the contradictory problem of poor safety of existing high-energy explosives.

Description

[0001] The present invention relates to the technical field of explosives, and particularly to an explosive with a strong acid-inhibiting coating structure and a preparation method thereof. Background Art

[0002] With the increasingly complex combat environment and the continuous enhancement of target protection capabilities, how to improve the safety performance and killing power of general-purpose blasting warheads is an urgent problem for weapon developers. Compared with other types of charges, pressed shaped charge explosives have better mechanical strength and environmental adaptability, are simple to prepare and load, and have the advantages of large-scale production and non-war reserve. After being pressed into shape, they can be easily loaded into warheads with relatively regular shapes, or directly pressed into the projectile body to form, and can be widely used in medium and large caliber and missile warhead charges, which can effectively improve the damage ability of our country's weapons and equipment.

[0003] 3-Nitro-1,2,4-triazol-5-one (3-nitro-1,2,4-triazol-5-one, abbreviated as NTO) has a high energy density, good thermal stability and appropriate mechanical sensitivity, and is a very promising insensitive energetic material. NTO-based explosives have been widely studied in various countries in recent years due to their advantages such as relatively low cost, low sensitivity and excellent performance. After years of development, they have now been successfully applied to solid ammunition and are widely used. However, due to the strong acidic property of the NTO molecule, when NTO comes into contact with metal, its acidity will corrode the metal shell, which will affect the safety of the long-term transportation and storage of the explosive and the stability of the explosive. Therefore, there is less research in the field of the formulation of pressed explosives based on NTO. If we want to utilize the advantages of NTO while avoiding the harm caused by its acidity, generally, a polymer binder is used to coat it to avoid direct contact with metal. For pressed explosives, high pressure is involved in the preparation process, and in this process, the phenomenon of NTO elemental separation from the polymer binder will occur, resulting in coating failure, which further increases the impact of corrosion on external metal materials. Therefore, personnel in the relevant technical fields and research institutions need to solve the problem of suppressing the acidity of NTO during its application to reduce the corrosion of the warhead metal. Summary of the Invention

[0004] To effectively solve the above problems, the present invention provides an explosive with a strong acid-inhibiting coating structure and a preparation method thereof. By utilizing the large specific surface area and a relatively large number of O-H bonds on the surface of nano-Fe2O3 powder, a strong intermolecular interaction occurs with NTO molecules, and a layer of nano-Fe2O3 powder with comprehensive acid buffering and heat conduction properties is uniformly coated on the surface of NTO. Through the spray drying process, while refining the NTO micron particles, the temperature is raised to achieve the full interaction between the NTO micron particles and the nano-Fe2O3 powder. Finally, a core-shell structure composite material with acid inhibition, heat conduction, and desensitization is obtained, improving the comprehensive safety performance of the explosive.

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

[0006] A preparation method of an explosive with a strong acid-inhibiting coating structure, comprising the following steps:

[0007] (1) Preparation of a supersaturated energetic material suspension: Take an excessive amount of NTO micron particles, add deionized water, and then stir and let stand. Take the supernatant to prepare a saturated NTO aqueous solution. Then take a quantitative amount of NTO micron particles and add a small amount of the NTO saturated solution to obtain a supersaturated NTO suspension;

[0008] (2) Preparation of a nano-Fe2O3 dispersion: Take a certain amount of nano-Fe2O3 powder and add deionized water and / or an anhydrous ethanol solution, stir, add a surfactant dropwise, and then ultrasonically disperse to prepare a nano-Fe2O3 dispersion;

[0009] (3) Preparation of an explosive with a strong acid-inhibiting coating structure: Pour the nano-Fe2O3 dispersion into a beaker containing the supersaturated NTO suspension and stir and mix. Then use the spray drying process for the mixed slurry of the supersaturated NTO suspension and the nano-Fe2O3 dispersion, and finally obtain the explosive with a strong acid-inhibiting coating structure after washing and drying.

[0010] Preferably, the size of the NTO micron particles in step (1) is in the range of 10 - 1000 μm.

[0011] Preferably, the purity of the NTO micron particles in step (1) is ≥ 98%.

[0012] Preferably, the mass-volume ratio of the excessive NTO micron particles to deionized water in step (1) is (15 - 50) g : (300 - 600) mL;

[0013] Preferably, the stirring speed in step (1) is 100 - 300 r / min, the stirring time is 5 - 30 min, and the standing time is 10 - 120 min;

[0014] Preferably, the mass - volume ratio of the quantitative NTO micron particles to a small amount of NTO saturated solution in step (1) is (5 - 20) g:(10 - 100) mL;

[0015] Preferably, the particle size of the nano - Fe₂O₃ powder in step (2) is 10 - 200 nm;

[0016] Preferably, the mass - volume ratio of the nano - Fe₂O₃ powder to deionized water and / or anhydrous ethanol solution in step (2) is (0.01 - 0.5) g:(10 - 100) mL, and the volume ratio of deionized water to anhydrous ethanol is 0.1 - 1;

[0017] Preferably, the stirring speed in step (2) is 150 - 550 r / min, and the stirring time is 10 - 30 min,

[0018] Preferably, the surfactant in step (2) is any one of cetyltrimethylammonium bromide, octadecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and dodecyltrimethylammonium bromide.

[0019] Preferably, the dosage of the surfactant in step (2) is 0.5 - 3% by mass fraction;

[0020] Preferably, the ultrasonic frequency and power in step (2) are 20 kHz and 800 W respectively, the ultrasonic time is 3 - 40 min, and the ultrasonic temperature is 35 - 75 °C;

[0021] Preferably, the mass ratio of the solids content in the supersaturated NTO suspension and the nano - Fe₂O₃ dispersion in step (3) is (5 - 20) g:(0.01 - 0.5) g;

[0022] Preferably, the stirring speed in step (3) is 200 - 700 r / min, and the stirring time is 5 - 30 min;

[0023] Preferably, nitrogen is introduced in the spray - drying process in step (3), and the flow rate is 4 - 10 L / min;

[0024] Preferably, the inlet temperature in the spray - drying process in step (3) is 80 - 120 °C;

[0025] Preferably, the inlet temperature in the spray - drying process in step (3) is 55 - 75 °C;

[0026] Preferably, in the washing process in step (3), a mixed solution of anhydrous ethanol and / or deionized water is used to wash 2 - 4 times, and the volume ratio of deionized water to anhydrous ethanol is (1 - 10):1;

[0027] Preferably, the drying condition in step (3) is vacuum drying at 50~105°C for 2~12h.

[0028] The above-mentioned explosive with a strong acid-inhibiting coating structure and its preparation method have the following beneficial effects compared with the prior art:

[0029] (1) For the explosive with a strong acid-inhibiting coating structure of the present invention, a novel composite coating structure is prepared on the surface of the explosive. By utilizing the high specific surface area and a large number of hydroxyl groups on the surface of nano-Fe2O3 powder, a strong interaction occurs with NTO containing more acidic N-H bonds in the molecule, forming a composite material with a core-shell structure, which can effectively inhibit the acidity on the surface of NTO, reduce the corrosion effect on the warhead shell material, and solve the problem of poor safety of the explosive.

[0030] (2) For the preparation method of the explosive with a strong acid-inhibiting coating structure of the present invention, it is prepared by adopting a spray drying process. The process is simple, the operation is safe, it has mature preparation process parameters, is easy to scale up for engineering, has a good application prospect, and currently this preparation method has strong universality and is suitable for surface coating of NTO explosives with different morphologies and particle sizes.

[0031] (3) For the explosive with a strong acid-inhibiting coating structure of the present invention, by using the spray drying process and regulating parameters, refined NTO micron particles can be obtained, and a layer of nano-Fe2O3 powder is uniformly coated on the surface of NTO. On the basis of effectively inhibiting the acidity of NTO, it plays a role in reducing sensitivity and optimizing the thermal conductivity of the explosive, realizing the comprehensive optimization of the performance of NTO explosive particles. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0033] Figure 1 It is the preparation flow chart of the present invention;

[0034] Figure 2 It is the structural schematic diagram of the explosive of the present invention;

[0035] Figure 3a It is the microscopic morphology diagram of untreated NTO particles;

[0036] Figure 3b It is the scanning electron microscope image of the core-shell structure of Fe2O3 powder-coated NTO micron particles. Detailed Embodiments

[0037] The present invention will be described in detail below in conjunction with embodiments and the accompanying drawings. It should be understood, however, that the embodiments and the drawings are only used for an exemplary description of the present invention and do not constitute any limitation to the protection scope of the present invention. All reasonable transformations and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0038] As Figure 1 shown, the present invention provides a method for preparing an explosive with a strong acid-inhibiting coating structure, and the method comprises the following steps:

[0039] (1) Preparation of a supersaturated energetic material suspension: Take NTO micron particles, add deionized water, then stir and let stand, and take the supernatant to prepare a saturated NTO aqueous solution. Then take a quantitative amount of NTO micron particles and add a small amount of the NTO saturated solution to obtain a supersaturated NTO suspension;

[0040] (2) Preparation of a nano-Fe2O3 dispersion: Take a certain amount of nano-Fe2O3 powder and add deionized water and / or an anhydrous ethanol solution, stir, dropwise add a surfactant, and then ultrasonically disperse to prepare a nano-Fe2O3 dispersion;

[0041] (3) Preparation of an explosive with a strong acid-inhibiting coating structure: Pour the nano-Fe2O3 dispersion into a beaker containing the supersaturated NTO suspension and stir and mix. Then use the spray drying process for the mixed slurry of the supersaturated NTO suspension and the nano-Fe2O3 dispersion, and finally obtain an explosive with a strong acid-inhibiting coating structure through filtration, washing, and drying.

[0042] According to the present invention, the size of the NTO micron particles is in the range of 10 - 1000 μm, and the purity of the NTO micron particles ≥ 98%.

[0043] Preferably, the mass-volume ratio of the excessive NTO micron particles to deionized water in step (1) is (15 - 50) g : (300 - 600) mL; the stirring speed is 100 - 300 r / min, the stirring time is 5 - 30 min, and the standing time is 10 - 120 min; the mass-volume of the quantitative NTO micron particles and the small amount of the NTO saturated solution is (5 - 20) g : (10 - 100) mL.

[0044] According to the present invention, the particle size of the nano-Fe2O3 powder described in step (2) is 10 to 200 nm; the mass-volume ratio of the nano-Fe2O3 powder to deionized water and / or absolute ethanol solution is (0.01 to 0.5) g : (10 to 100) mL, and the volume ratio of deionized water to absolute ethanol is 0.1 to 1; the stirring speed is 150 to 550 r / min, and the stirring time is 10 to 30 min; the surfactant is any one of cetyltrimethylammonium bromide, octadecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and dodecyltrimethylammonium bromide; the dosage of the surfactant is 0.5 to 3% by mass fraction;

[0045] According to the present invention, the ultrasonic frequency and power for the nano-Fe2O3 powder are 20 kHz and 800 W respectively, the ultrasonic time is 3 to 40 min, and the ultrasonic temperature is 35 to 75 °C.

[0046] In the present invention, the mass ratio of the solids content in the supersaturated NTO suspension and the nano-Fe2O3 dispersion described in step (3) is (5 to 20) g : (0.01 to 0.5) g; the stirring speed is 200 to 700 r / min, and the stirring time is 5 to 30 min;

[0047] Specifically, according to the present invention, the inlet temperature in the spray drying process described in step (3) is 80 to 120 °C; the outlet temperature is 55 to 75 °C; nitrogen is introduced into the system at a flow rate of 4 to 10 L / min; it is washed 2 to 4 times with a mixed solution of absolute ethanol and / or deionized water; vacuum drying is carried out at 50 to 105 °C, and the drying time is 2 to 12 h.

[0048] By preparing a new composite coating structure on the surface of the explosive, using the high specific surface area and a large number of O-H bonds of the nano-Fe2O3 powder, a strong interaction is generated with the NTO molecules, thereby effectively inhibiting the escape process of H+ ions on the surface of the NTO molecules, thereby reducing the acidity of NTO, reducing the harm to the metal material of the warhead shell. On the other hand, using the spray drying process, the NTO micron particles are refined to obtain a composite material in which the nano-Fe2O3 powder coating is uniformly distributed on the surface of the NTO micron particles, as Figure 2 shown, 1 represents the nano-Fe2O3 powder, and 2 represents the micron NTO crystal particles; the sensitivity of the explosive is effectively reduced and the thermal conductivity is optimized, endowing the composite material with excellent comprehensive performance. As Figure 3a is the microscopic morphology diagram of the untreated NTO particles; as Figure 3b is the scanning electron microscope image of the core-shell structure of the Fe2O3 powder-coated NTO micron particles.

[0049] Example 1:

[0050] According to the technical solution of the present invention, a method for preparing an explosive with a strong acid-inhibiting coating structure includes the following steps:

[0051] (1) Preparation of supersaturated energetic material suspension: Take 15 g of NTO micron particles, add 300 mL of deionized water, then stir at a stirring speed of 100 r / min for 10 min, let stand for 10 min, and take the supernatant to prepare a saturated NTO aqueous solution. Then take 5 g of NTO micron particles and add 10 mL of NTO saturated solution to obtain a supersaturated NTO suspension;

[0052] (2) Preparation of nano-Fe2O3 dispersion: Take 0.3 g of nano-Fe2O3 powder with a particle size of 10 nm, then add 30 mL of deionized water, stir at a speed of 550 r / min for 30 min, add cetyltrimethylammonium bromide with a mass fraction of 1%, and then perform ultrasonic dispersion at a frequency of 20 kHz and a power of 800 W for 30 min. The ultrasonic temperature is 60 °C to prepare a nano-Fe2O3 dispersion;

[0053] (3) Preparation of an explosive with a strong acid-inhibiting coating structure: Pour the nano-Fe2O3 dispersion into a beaker containing the supersaturated NTO suspension, stir at a speed of 500 r / min for 20 min to obtain a well-mixed slurry of the supersaturated NTO suspension and the nano-Fe2O3 dispersion. Using the spray drying process, set the inlet temperature to 110 °C and the outlet temperature to 70 °C, introduce nitrogen into the system at a flow rate of 4 L / min, and finally wash 3 times with a mixed solution of deionized water and absolute ethanol with a volume ratio of 1:1, and vacuum dry at 60 °C for 6 h to finally obtain an explosive with a strong acid-inhibiting coating structure.

[0054] Example 2

[0055] According to the technical solution of the present invention, a method for preparing an explosive with a strong acid-inhibiting coating structure includes the following steps:

[0056] (1) Preparation of supersaturated energetic material suspension: Take 30 g of NTO micron particles, add 400 mL of deionized water, then stir at a stirring speed of 200 r / min for 20 min, let stand for 20 min, and take the supernatant to prepare a saturated NTO aqueous solution. Then take 8 g of NTO micron particles and add 15 mL of NTO saturated solution to obtain a supersaturated NTO suspension;

[0057] (2) Preparation of nano-Fe2O3 dispersion: Take 0.2 g of nano-Fe2O3 powder with a particle size of 20 nm, then add 50 mL of deionized water, stir at a speed of 500 r / min for 30 min, add octadecyltrimethylammonium bromide with a mass fraction of 1.5%, and then perform ultrasonic dispersion at a frequency of 20 kHz and a power of 800 W for 20 min. The ultrasonic temperature is 65 °C to obtain the nano-Fe2O3 dispersion;

[0058] (3) Preparation of an explosive with a strong acid-inhibiting coating structure: Pour the nano-Fe2O3 dispersion into a beaker containing a supersaturated NTO suspension, stir at a speed of 600 r / min for 15 min to obtain a well-mixed slurry of the supersaturated NTO suspension and the nano-Fe2O3 dispersion. Using the spray drying process, set the inlet temperature to 120 °C and the outlet temperature to 75 °C. Pass nitrogen into the system at a flow rate of 5 L / min. Finally, filter and wash 4 times with a mixed solution of deionized water and absolute ethanol with a volume ratio of 2:1, and vacuum dry at 65 °C for 8 h to finally obtain an explosive with a strong acid-inhibiting coating structure.

[0059] Example 3

[0060] According to the technical solution of the present invention, a method for preparing an explosive with a strong acid-inhibiting coating structure includes the following steps:

[0061] (1) Preparation of a supersaturated energetic material suspension: Take 35 g of NTO micron particles, add 350 mL of deionized water, then stir at a stirring speed of 300 r / min for 30 min, let it stand for 30 min, and take the supernatant to prepare a saturated NTO aqueous solution. Then take 15 g of NTO micron particles and add 50 mL of the NTO saturated solution to obtain a supersaturated NTO suspension;

[0062] (2) Preparation of nano-Fe2O3 dispersion: Take 0.3 g of nano-Fe2O3 powder with a particle size of 30 nm, then add 30 mL of deionized water, stir at a speed of 500 r / min for 30 min, add octadecyltrimethylammonium bromide with a mass fraction of 2%, and then perform ultrasonic dispersion at a frequency of 20 kHz and a power of 800 W for 40 min. The ultrasonic temperature is 70 °C to obtain the nano-Fe2O3 dispersion;

[0063] (3) Preparation of an explosive with a strong acid-inhibiting coating structure: Pour the nano-Fe₂O₃ dispersion into a beaker containing a supersaturated NTO suspension, stir at a speed of 700 r / min for 25 min to obtain a well-mixed slurry of the supersaturated NTO suspension and the nano-Fe₂O₃ dispersion. Using the spray drying process, set the inlet temperature at 95 °C and the outlet temperature at 65 °C, introduce nitrogen into the system at a flow rate of 6 L / min, and finally filter and wash twice with a mixed solution of deionized water and absolute ethanol with a volume ratio of 4:1. After vacuum drying at 60 °C for 8 h, an explosive with a strong acid-inhibiting coating structure is finally obtained.

[0064] Example 4

[0065] According to the technical solution of the present invention, a method for preparing an explosive with a strong acid-inhibiting coating structure includes the following steps:

[0066] (1) Preparation of a supersaturated energetic material suspension: Take 40 g of NTO micron particles, add 500 mL of deionized water, and then stir at a stirring speed of 300 r / min for 30 min. After standing for 60 min, take the supernatant to prepare a saturated NTO aqueous solution. Then take 10 g of NTO micron particles and add 40 mL of the NTO saturated solution to obtain a supersaturated NTO suspension;

[0067] (2) Preparation of the nano-Fe₂O₃ dispersion: Take 0.5 g of nano-Fe₂O₃ powder with a particle size of 60 nm, and then add it to a mixed solution of 100 mL of deionized water and absolute ethanol (volume ratio 1:1), stir at a speed of 500 r / min for 20 min, add dodecyltrimethylammonium bromide with a mass fraction of 3%, and then perform ultrasonic dispersion at a frequency of 20 kHz and a power of 800 W for 30 min. The ultrasonic temperature is 60 °C to prepare the nano-Fe₂O₃ dispersion;

[0068] (3) Preparation of an explosive with a strong acid-inhibiting coating structure: Pour the nano-Fe₂O₃ dispersion into a beaker containing a supersaturated NTO suspension, stir at a speed of 500 r / min for 30 min to obtain a well-mixed slurry of the supersaturated NTO suspension and the nano-Fe₂O₃ dispersion. Using the spray drying process, set the inlet temperature at 105 °C and the outlet temperature at 75 °C, introduce nitrogen into the system at a flow rate of 7 L / min, and finally filter and wash three times with a mixed solution of deionized water and absolute ethanol with a volume ratio of 5:1. After vacuum drying at 80 °C for 10 h, an explosive with a strong acid-inhibiting coating structure is finally obtained.

[0069] Example 5

[0070] According to the technical solution of the present invention, a method for preparing an explosive with a strong acid-inhibiting coating structure includes the following steps:

[0071] (1) Preparation of supersaturated energetic material suspension: Take 50 g of NTO micron particles, add 600 mL of deionized water, and then stir at a stirring speed of 300 r / min for 30 min. After standing for 120 min, take the supernatant to prepare a saturated NTO aqueous solution. Then take 20 g of NTO micron particles and add 100 mL of NTO saturated solution to obtain a supersaturated NTO suspension;

[0072] (2) Preparation of nano-Fe2O3 dispersion: Take 0.4 g of nano-Fe2O3 powder with a particle size of 120 nm, and then add it to a mixed solution of 80 mL of deionized water and absolute ethanol (volume ratio 2:1). Stir at a speed of 400 r / min for 30 min, add tetrabutylammonium bromide with a mass fraction of 2%, and then perform ultrasonic dispersion at a frequency of 20 kHz and a power of 800 W for 30 min. The ultrasonic temperature is 65 °C to prepare a nano-Fe2O3 dispersion;

[0073] (3) Preparation of an explosive with a strong acid-inhibiting coating structure: Pour the nano-Fe2O3 dispersion into a beaker containing the supersaturated NTO suspension, stir at a speed of 700 r / min for 20 min to obtain a well-mixed slurry of the supersaturated NTO suspension and the nano-Fe2O3 dispersion. Using the spray drying process, set the inlet temperature to 100 °C and the outlet temperature to 70 °C. Pass nitrogen into the system at a flow rate of 8 L / min. Finally, after filtration, wash 4 times with a mixed solution of deionized water and absolute ethanol with a volume ratio of 4:1, and dry in vacuum at 90 °C for 12 h to finally obtain an explosive with a strong acid-inhibiting coating structure.

[0074] It can be seen from the microscopic morphology diagram of the NTO micron particles and the explosive with a strong acid-inhibiting coating structure prepared in Example 3 in Figure 3 that through the preparation method provided by the present invention, the particle size of the NTO micron particles is reduced, and the surface of the NTO is completely and uniformly coated with nano-Fe2O3 powder to form a core-shell structure.

[0075] Take 5 g of NTO micron particles and the explosives with a strong acid-inhibiting coating structure prepared in Examples 1-5 in 100 mL of deionized water, stir and then stand for 30 min, take the supernatant to test its pH value, and the test results are shown in Table 1.

[0076] From the results in Table 1, it can be obtained that through the preparation method provided by the present invention, the acidity of the composite material with a coating layer prepared is significantly reduced compared with the NTO micron particles, and the acidity of the NTO is effectively inhibited.

[0077] Table 1 pH values of NTO and explosives with a strong acid-inhibiting coating structure

[0078] Sample solution (5 g / 100 mL) pH value (average value obtained three times) Example 1 6.21 Example 2 6.14 Example 3 6.07 Example 4 5.96 Example 5 5.89 NTO 3.6

[0079] The above specific description further details the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above is only a specific embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of an explosive with a strong acid-inhibiting coating structure, characterized in that, By utilizing the large specific surface area and numerous O-H bonds on the surface of nano-Fe2O3 powder, strong intermolecular interactions occur with NTO molecules, and a layer of nano-Fe2O3 powder with comprehensive acid buffering and heat conduction properties is uniformly coated on the surface of NTO. Through the spray drying process, while refining the NTO micron particles, heating is carried out to achieve the full interaction between the NTO micron particles and the nano-Fe2O3 powder. Finally, a core-shell structure composite material with acid inhibition, heat conduction, and sensitivity reduction is obtained.

2. The preparation method of an explosive with a strong acid-inhibiting coating structure according to claim 1, characterized in that, Specifically, it includes the following steps: (1) Preparation of supersaturated energetic material suspension: Take an excessive amount of NTO micron particles, add deionized water, then stir and let stand, and take the supernatant to prepare a saturated NTO aqueous solution; then take a quantitative amount of NTO micron particles and add them to the NTO saturated solution to obtain a supersaturated NTO suspension. (2) Preparation of nano-Fe2O3 dispersion: Add nano-Fe2O3 powder to deionized water and / or absolute ethanol solution, stir, add a surfactant dropwise, and then perform ultrasonic dispersion to prepare a nano-Fe2O3 dispersion. (3) Preparation of an explosive with a strong acid-inhibiting coating structure: Pour the nano-Fe2O3 dispersion into a beaker containing the supersaturated NTO suspension and stir to mix; then use the spray drying process for the mixed slurry of the supersaturated NTO suspension and the nano-Fe2O3 dispersion, and finally obtain an explosive with a strong acid-inhibiting coating structure after washing and drying.

3. The preparation method of an explosive with a strong acid-inhibiting coating structure according to claim 2, characterized in that, The size of the NTO micron particles is in the range of 10 - 1000 μm, and the purity is ≥98%.

4. The preparation method of an explosive with a strong acid-inhibiting coating structure according to claim 2, characterized in that, The mass-volume ratio of the excessive NTO micron particles to deionized water is 15 - 50 g: 300 - 600 mL, the stirring speed is 100 - 300 r / min, the stirring time is 5 - 30 min, and the standing time is 10 - 120 min.

5. The preparation method of an explosive with a strong acid suppression coating structure according to claim 2, characterized in that, The mass-volume of the quantitative NTO micron particles to the NTO saturated solution is 5 - 20 g: 10 - 100 mL.

6. The preparation method of an explosive with a strong acid suppression coating structure according to claim 2, characterized in that, The particle size of the nano-Fe2O3 powder is in the range of 10 - 200 nm, the mass-volume ratio of the nano-Fe2O3 powder to deionized water and / or absolute ethanol solution is 0.01 - 0.5 g: 10 - 100 mL, the volume ratio of deionized water to absolute ethanol is 0.1 - 1, the stirring speed is 150 - 550 r / min, and the stirring time is 10 - 30 min.

7. The preparation method of an explosive with a strong acid-inhibiting coating structure according to claim 2, characterized in that, The surfactant is any one of cetyltrimethylammonium bromide, octadecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and dodecyltrimethylammonium bromide, and the dosage is 0.5 - 3% mass fraction of the nano-Fe2O3 dispersion. The frequency and power of ultrasonic dispersion are 20 kHz and 800 W respectively, the ultrasonic time is 3 - 40 min, and the ultrasonic temperature is 35 - 75 °C.

8. The preparation method of an explosive with a strong acid suppression coating structure according to claim 2, characterized in that, The mass ratio of the solids content in the supersaturated NTO suspension and the nano-Fe2O3 dispersion is 5 - 20 g: 0.01 - 0.5 g, the stirring speed is 200 - 700 r / min, and the stirring time is 5 - 30 min.

9. The preparation method of an explosive with a strong acid suppression coating structure according to claim 2, characterized in that, In the spray drying process, nitrogen is introduced with a flow rate of 4 - 10 L / min, the inlet temperature is 80 - 120 °C, the outlet temperature is 55 - 75 °C, and it is washed 2 - 4 times with a mixed solution of absolute ethanol and / or deionized water. The volume ratio of deionized water to absolute ethanol is 1 - 10:

1. The drying is carried out under vacuum at 50 - 105 °C, and the drying time is 2 - 12 h.

10. An explosive with a strong acid-inhibiting coating structure, characterized in that, It is prepared by using the preparation method according to any one of claims 1 - 9.

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