A process for on-site mixing of biodiesel-based compound ammonium nitrate explosives

Abstract

This invention relates to the field of industrial explosives technology and discloses a field mixing process for biodiesel-based ammonium nitrate explosives. The process involves continuously conveying porous granular ammonium nitrate; injecting light diesel oil at the front end of the conveying process to allow it to penetrate the internal micropores; after 8-20 seconds of penetration, injecting preheated biodiesel (30-40°C) in the middle to later stages of the conveying process to form an oxygen-rich combustion layer on the outer surface of the particles; the biodiesel is premixed with a hydrophobic modifier. This invention solves the problem of insufficient internal sensitization caused by the high viscosity and poor permeability of biodiesel through stepwise mixing of diesel and biodiesel, combined with the interface control of the modifier. Furthermore, it utilizes the oxygen-containing characteristics of biodiesel and the hydrophobic network of the modifier to construct a stable oxygen-rich layer, improving oxygen balance, increasing the explosive energy release rate and moisture resistance, and making the explosive superior to or equivalent to the pure diesel process in terms of detonation velocity, saturation, storage stability, and initiation sensitivity.

Description

Technical Field

[0001] This invention relates to the field of industrial explosives technology, and in particular to a process for on-site mixing of biodiesel-based ammonium nitrate explosives. Background Technology

[0002] Porous granular ammonium nitrate explosives (ANFO) are composed of porous granular ammonium nitrate and fuel oils such as diesel. Due to their low cost, good flowability, and high safety, they are widely used in mixed blasting operations in large open-pit mines. In recent years, biomass fuel oil (CO) has been regarded as a potential oil phase material to replace or partially replace diesel due to its advantages such as renewability, low sulfur content, high flash point, and high combustion efficiency, and has attracted attention in the field of ammonium nitrate explosives.

[0003] Existing studies have explored the feasibility of biodiesel in ammonium nitrate (AM) explosives. For example, Chinese patent CN102320904A discloses the application of biodiesel in the production of porous granular AM explosives, and a method for preparing porous granular AM explosives at room temperature by completely or partially replacing light diesel oil with biodiesel. Chinese patent CN119241321A discloses safe and environmentally friendly porous granular AM explosives and their preparation method, and further proposes to use 3%-9% of biomass oils such as cashew nut shell oil in combination with porous granular ammonium nitrate. However, the introduction of biodiesel may affect the thermal stability of ammonium nitrate. The above studies have focused on substitution or premixing at the formulation level, without addressing the adaptive improvement of the on-site mixing process.

[0004] The paper "Research and Application of Biomass Fuel Oil in ANFO Explosives" published by Li Junjie et al. in *Engineering Blasting* reveals that CO / ANFO explosives have relatively weak performance in field blasting applications. This is mainly because the kinematic viscosity of CO is higher than that of diesel (DO), resulting in relatively low mixing uniformity between CO and porous granular ammonium nitrate (PPAN) during the preparation of ANFO explosives in mixed ANFO trucks. This leads to incomplete local detonation of CO / ANFO. If biodiesel is used to partially replace diesel for simple mixing, the amount of oil adsorbed by the micropores inside the ammonium nitrate particles will be insufficient, hindering the formation of hot spots and reducing detonation sensitivity and detonation velocity. At the same time, the oxygen-containing characteristics of biodiesel are not utilized in a targeted manner, the particle surface lacks an oxygen-rich combustion layer, the oxygen balance is difficult to optimize, and the explosive energy is not fully released. Summary of the Invention

[0005] The technical problem to be solved by this invention is: when using biodiesel to partially replace diesel to prepare on-site mixed porous granular ammonium nitrate explosives, how to overcome the defect that biodiesel is difficult to enter the micropores of porous ammonium nitrate due to its high viscosity and poor permeability, resulting in insufficient internal sensitization, and at the same time utilize the oxygen-containing characteristics of biodiesel to form an oxygen-rich combustion layer on the particle surface to optimize the oxygen balance in the detonation reaction zone. To this end, we propose an on-site mixing process for biodiesel-blended ammonium nitrate explosives.

[0006] To achieve the above objectives, this application adopts the following technical solution: Based on the above technical solution, a complete and detailed implementation method is provided, including a description of the materials used, and the experimental steps and principles to the greatest extent possible. These are not included in the examples, and the examples and comparative examples are separate parts, including the following steps: S1: Porous granular ammonium nitrate is continuously conveyed, and light diesel oil is sprayed into the porous granular ammonium nitrate at the front end of the conveying process, so that it preferentially penetrates into the internal micropores of the porous granular ammonium nitrate particles, and a penetration time of 8-20 seconds is allowed after the light diesel oil is sprayed in; S2: In the middle and later stages of the conveying process, preheated biodiesel to 30℃-40℃ is sprayed into the porous granular ammonium nitrate, so that it adheres to the outer surface of the particles to form an oxygen-rich combustion layer; the biodiesel is premixed with a hydrophobic modifier.

[0007] Preferably, the amount of light diesel oil injected accounts for 2.5%-3.5% of the total mass of the explosive, the amount of biodiesel injected accounts for 2.0%-3.0% of the total mass of the explosive, and the amount of porous granular ammonium nitrate accounts for 94%-95% of the total mass of the explosive.

[0008] Preferably, the light diesel oil is selected from commercially available No. 0 or No. -10 light diesel oil.

[0009] Preferably, the hydrophobic modifier is selected from one or more of silane coupling agents, surfactants, and nanoparticles.

[0010] Preferably, the amount of the nanoparticles added accounts for 0.5%-2.0% of the biodiesel mass.

[0011] Preferably, the amount of surfactant added accounts for 0.3%-1.5% of the biodiesel mass.

[0012] Preferably, the amount of the silane coupling agent added accounts for 0.3%-1.2% of the biodiesel mass.

[0013] Preferably, the biodiesel is ester-based biodiesel, which is a fatty acid methyl ester or ethyl ester produced by transesterification of vegetable oil, animal oil, waste oil or microbial oil.

[0014] Preferably, the injection point of the light diesel oil is located 0.3m-1.0m from the inlet at the front end of the screw conveyor; the injection point of the biodiesel is located 1.5m-3.5m downstream of the injection point of the light diesel oil.

[0015] Preferably, the injection pressure for conveying light diesel oil is 0.2-0.6 MPa; and the injection pressure for conveying biodiesel is 0.6-1.0 MPa.

[0016] The technical effects and advantages of this invention are as follows: This invention utilizes a stepwise mixing sequence of first permeating with diesel fuel and then coating with biodiesel. The low viscosity and high permeability of diesel fuel preferentially fill the internal micropores of porous ammonium nitrate. Preheated biodiesel then forms an oxygen-containing coating layer on the particle surface, achieving spatial functional separation of the two oil phases. Simultaneously, premixing a hydrophobic modifier into the biodiesel reduces surface tension at the oil-solid interface, enhances spreadability, and forms a hydrophobic network to inhibit water intrusion and oil phase migration. This process, without altering the main equipment structure of existing mixing vehicles, achieves both internal sensitization and surface functionalization by adjusting the injection timing, preheating temperature, and selectively adding modifiers. It also helps extend the storage stability of explosives, providing an industrially feasible process route for the partial replacement of diesel fuel with biodiesel. Attached Figure Description

[0017] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts: Figure 1 The diagram shows the detonation velocity and saturation of various embodiments and comparative examples of the present invention; Figure 2 This is a graph showing the detonation velocity and saturation at different preheating temperatures for Example 4 of the present invention; Figure 3 The images show the burst velocity diagrams of various embodiments and comparative examples of the present invention after 15 days of storage. Detailed Implementation

[0018] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0019] This invention provides a process for on-site mixing of biodiesel-based compound ammonium nitrate explosives, comprising the following steps: S1: Add porous granular ammonium nitrate to the hopper of the on-site mixing truck, start the screw conveyor, and control the conveying speed to 0.1m / s-0.5m / s, corresponding to a conveying capacity of 5t / h-30t / h. The ammonium nitrate particles remain loose and continuously flowing during the conveying process.

[0020] S2: After the screw conveyor is started, the diesel fuel injection system is turned on at a distance of 0.3m-1.0m from the front end of the conveyor. Light diesel fuel is sprayed onto the flowing ammonium nitrate particles through a pressure atomizing nozzle at a pressure of 0.2MPa-0.6MPa.

[0021] S3: After the light diesel oil is injected, maintain a penetration time of 8-20 seconds to allow the diesel oil to fully penetrate into the internal micropores of the porous granular ammonium nitrate particles.

[0022] S4: Utilize the existing oil phase preheating device in the blending vehicle, such as an electric heating belt, engine waste heat exchanger, or hot water jacket, to heat the biodiesel to 30℃-40℃. After preheating, its kinematic viscosity decreases from 30 mmHg. 2 / s-45mm 2 / s decreased to approximately 10mm 2 / s-20mm 2 / s, add a hydrophobic modifier to the preheated biodiesel, and stir or circulate to mix evenly.

[0023] S5: At a distance of 1.5m-3.5m downstream of the diesel injection point, turn on the biodiesel injection system, using a pressure atomizing nozzle with an injection pressure of 0.6MPa-1.0MPa, and spray the preheated biodiesel containing the modifier onto the surface of the ammonium nitrate particles that have adsorbed diesel. When a modifier is added, the injection pressure can be appropriately reduced to 0.4MPa-0.9MPa without reducing the uniformity of coating.

[0024] S6: After being fully agitated and mixed by the screw conveyor, porous granular ammonium nitrate explosive with internal microporous adsorption of diesel oil and an external surface coated with an oxygen-rich layer is obtained at the discharge port, which can be directly unloaded into the blast hole for blasting operations.

[0025] Specifically, the porous granular ammonium nitrate is an industrial-grade product with the molecular formula NH4NO3. Its particle size is typically 0.5mm-2.5mm, and the particles have a well-developed microporous structure with a pore size distribution mainly between 10μm and 100μm. The bulk density is 0.75g / cm³. 3 -0.85g / cm 3 The amount used accounts for 94%-95% of the total mass of explosives.

[0026] The light diesel oil is selected from commercially available No. 0 or No. -10 light diesel oil, with a kinematic viscosity of 2.0 mm at 40°C. 2 s-4.5mm 2 / s, flash point ≥60℃, No. 0 diesel pour point ≤0℃, No. -10 diesel pour point ≤-10℃, the amount used accounts for 2.5%-3.5% of the total mass of explosives; the main function of light diesel is as a highly permeable fuel, preferentially entering the micropores of ammonium nitrate particles to form sensitized hot spots.

[0027] The biodiesel is ester-based biodiesel, which is fatty acid methyl ester or ethyl ester produced by transesterification of vegetable oil, animal oil, waste oil, or microbial oil, and has a kinematic viscosity of 30 mmHg at 40°C. 2 / s-45mm 2 / s, flash point ≥130℃, acid value ≤2.0mgKOH / g, moisture content ≤0.05%, oxygen content about 10%-11%, and dosage accounts for 2.0%-3.0% of the total mass of the explosive; the main function of biodiesel is as an oxygen-containing fuel, which is coated on the surface of ammonium nitrate particles to form an oxygen-rich combustion layer.

[0028] The light diesel oil is injected at a lower pressure of 0.4MPa-0.6MPa to form larger droplets with an average particle size of 100μm-150μm, which facilitates its spread on the surface of ammonium nitrate particles and its natural absorption into micropores by capillary action. The biodiesel is injected at a higher pressure of 0.6MPa-0.8MPa to form fine droplets with an average particle size of 50μm-80μm, which increases the uniformity of surface coverage.

[0029] The hydrophobic modifier is selected from one or more of silane coupling agents, surfactants, and nanoparticles, and its addition amount accounts for 0.5%-2.0% of the biodiesel mass; the modifier is uniformly dispersed in preheated biodiesel without causing significant thickening or stratification.

[0030] Specifically, the surfactants are selected from sorbitan monooleate (Span-80), polyoxyethylene sorbitan monooleate (Tween-80), and their compound systems. Span-80 and Tween-80 are recognized in the field as excellent water-in-oil or oil-in-water surfactants that can be uniformly dispersed in biodiesel. When biodiesel is sprayed onto the surface of ammonium nitrate particles, the surfactant molecules are anchored in the oil film through hydrophobic alkyl chains, and the polar head groups are adsorbed on the polar surface of ammonium nitrate to form a directional monolayer, which reduces the contact angle of the oil-solid interface and makes the coating layer thinner and more continuous. The amount of surfactant added accounts for 0.3%-1.5% of the biodiesel mass.

[0031] The nanoparticles are selected from hydrophobically modified nano-silica or hydrophobically modified bentonite. Nano-silica has a high specific surface area and good dispersibility. After hydrophobic modification, its surface changes from hydrophilic to hydrophobic, which can be uniformly dispersed in biodiesel. During spraying, the nanoparticles are distributed inside the oil film and at the oil-solid interface, forming a hydrophobic layer with a micro-nano composite structure on the surface of ammonium nitrate particles, effectively preventing water molecules from approaching the surface of ammonium nitrate. In addition, the nanoparticles embedded in the oil film play an anchoring role, which can reduce the migration and aggregation of biodiesel during long-term storage. The amount of nanoparticles added accounts for 0.5%-2.0% of the biodiesel mass.

[0032] The silane coupling agent is selected from either γ-aminopropyltriethoxysilane (KH-550) or γ-(methacryloyloxy)propyltrimethoxysilane (KH-570). The silane coupling agent has a dual-reaction function. One end can chemically bond with the polar groups on the surface of ammonium nitrate, and the other end is compatible with the long-chain alkyl groups in biodiesel, forming a covalently linked hydrophobic molecular layer on the surface of ammonium nitrate particles. Compared with physical adsorption, the hydrophobic layer provided by chemical bonding has higher stability and durability. The amount of crosslinking agent added accounts for 0.3%-1.2% of the biodiesel mass.

[0033] The core mechanism of this invention, which involves first permeating with diesel fuel and then coating functional zones with biodiesel, is as follows: Porous ammonium nitrate micropores have strong capillary adsorption force. The light diesel oil injected first has low viscosity and low surface tension, so it spreads and penetrates into the micropores quickly. After the micropores are occupied by diesel oil, the biodiesel injected later has high surface tension and high viscosity, so it cannot replace the diesel oil into the pores. Instead, it can only coat the outer surface of the particles, forming a functional zone where the internal diesel oil is sensitized and the external biodiesel is oxygen-enriched. If the oil is injected simultaneously or in reverse order, the biodiesel will block the orifice or compete for adsorption, resulting in insufficient oil inside and uneven oil layer outside.

[0034] After the addition of hydrophobic modifiers, it migrates to the oil-solid interface: surfactants reduce the contact angle, making the coating layer thinner and more continuous; nanoparticles or crosslinking agents form a hydrophobic network, improving moisture resistance, while anchoring the oil film, preventing migration and agglomeration, and extending the shelf life.

[0035] Furthermore, the effect of the modifier is synergistic with the injection sequence. Only when diesel is added first and then biodiesel can the modifier accurately act on the biodiesel layer on the outer surface, without interfering with the micropore filling of the internal diesel, and fully exert its function of reducing interfacial tension and forming a hydrophobic network. If the sequence is reversed, the modifier will preferentially adsorb onto the surface of ammonium nitrate, forming a hydrophobic film, which will hinder the subsequent diesel from entering the micropores, resulting in insufficient internal sensitization. If the two types of oil are injected at the same time, the modifier will intensify the surface occupation of biodiesel in the competitive adsorption, further reducing the diesel penetration.

[0036] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art should understand that various modifications and changes can be made to the present invention without departing from the technical principles of the present invention, and these modifications and changes should also fall within the scope of protection of the present invention.

[0037] Example 1 S1: Based on 100% of the total explosive mass, 94.5 kg of porous granular ammonium nitrate, with a particle size of 0.8 mm-2.0 mm, an oil absorption rate of 8.5%, a loose density of 0.80 g / cm³, and a moisture content of ≤0.3%; 3.0 kg of light diesel oil, using No. 0 light diesel oil, with a kinematic viscosity of 2.8 mm² / s at 40℃ and a flash point of 65℃; and 2.5 kg of biodiesel, using fatty acid methyl esters made from waste oil, with a kinematic viscosity of 38 mm² / s at 40℃, an acid value of 1.5 mg KOH / g, a flash point of 145℃, and an oxygen content of 10.5%.

[0038] S2: Add porous granular ammonium nitrate into the hopper of the on-site mixing truck, start the screw conveyor, set the conveying speed to 0.25m / s, and the total length of the screw conveyor is 4.5m. The ammonium nitrate particles remain loose and continuously flowing during the conveying process.

[0039] S3: The first set of pressure atomizing nozzles is set at a distance of 0.4m from the feed inlet of the screw conveyor. When the porous granular ammonium nitrate is conveyed to this position, the diesel injection system is turned on and 3.0kg of light diesel oil is evenly sprayed onto the surface of the flowing ammonium nitrate particles at an injection pressure of 0.5MPa. After the diesel oil is injected, the ammonium nitrate particles continue to be conveyed forward.

[0040] S4: Before injecting the biodiesel, the biodiesel is heated to 35°C using the electric heating device on the mixing vehicle. After preheating, the kinematic viscosity of the biodiesel is reduced to approximately 12 mmHg. 2 / s, add 1.0% of the biodiesel mass of hydrophobic modifier, namely hydrophobically treated nano-silica with an average particle size of 20nm, and stir to mix evenly.

[0041] S5: A second set of pressure atomizing nozzles is installed 2.8m away from the feed inlet of the screw conveyor. This nozzle is located downstream of the diesel nozzle. When the ammonium nitrate particles that have completed diesel permeation are transported to this position, the biodiesel injection system is turned on to spray 2.5kg of preheated biodiesel onto the particle surface at an injection pressure of 0.5MPa.

[0042] S6: After being tumbled and mixed in the subsequent section of the screw conveyor, porous granular ammonium nitrate explosives with internal micropores adsorbing diesel and external surface coated with biodiesel are obtained at the discharge port. The discharged explosives are directly loaded into sampling bags.

[0043] Example 2 This embodiment provides a process for on-site mixing of biodiesel-based ammonium nitrate explosives. The difference from Embodiment 1 is that the porous granular ammonium nitrate is 94.0%, light diesel oil is 3.5%, and biodiesel is 2.5%, while the rest is the same as in Embodiment 1.

[0044] Example 3 This embodiment provides a process for on-site mixing of biodiesel-based ammonium nitrate explosives. The difference from Embodiment 1 is that the porous granular ammonium nitrate is 95.0%, light diesel oil is 3.0%, and biodiesel is 2.0%, while the rest is the same as in Embodiment 1.

[0045] Example 4 This embodiment provides a process for on-site mixing of biodiesel-based ammonium nitrate explosives. The difference from Embodiment 1 is that only the preheating temperature of the biodiesel is changed, set to 25℃, 30℃, 40℃, and 45℃ respectively. The rest is the same as in Embodiment 1.

[0046] Example 5 This embodiment provides a process for on-site mixing of biodiesel-based ammonium nitrate explosives. The difference from Embodiment 1 is that no hydrophobic modifier is added, while the rest is the same as in Embodiment 1.

[0047] Comparative Example 1 This comparative example provides a process for on-site mixing of biodiesel-based ammonium nitrate explosives. The difference from Example 1 is that only a diesel nozzle is used, all diesel is injected at once, the injection pressure is 0.5 MPa, no preheating is required, no biodiesel is added, and the conveying speed is 0.25 m / s. The rest is the same as in Example 1.

[0048] Comparative Example 2 This comparative example provides a process for on-site mixing of biodiesel-based ammonium nitrate explosives. The difference from Example 1 is that only a biodiesel nozzle is used, the biodiesel is directly injected at room temperature, the injection pressure is 0.5 MPa, no preheating is required, and no diesel fuel is added. The rest is the same as in Example 1.

[0049] Comparative Example 3 This comparative example provides a process for on-site mixing of biodiesel-based ammonium nitrate explosives. The difference from Example 1 is that the biodiesel nozzle is first opened, the biodiesel is preheated to 35°C, and the injection pressure is 0.5 MPa. After about 10 seconds of conveying, the diesel nozzle is opened at a distance of 2.8 m from the feed inlet to inject light diesel oil. The rest is the same as in Example 1.

[0050] Comparative Example 4 This comparative example provides a process for on-site mixing of biodiesel-based ammonium nitrate explosives. The difference from Example 1 is that only a biodiesel nozzle is used, but the biodiesel is preheated to 35°C and injected in one go. The rest is the same as in Example 1.

[0051] Comparative Example 5 This comparative example provides a process for on-site mixing of biodiesel-based ammonium nitrate explosives. The difference from Example 1 is that the diesel nozzle and the biodiesel nozzle are set in the same position, and the two injection systems are turned on simultaneously. Otherwise, it is the same as Example 1.

[0052] Comparative Example 6 This comparative example provides a process for on-site mixing of biodiesel-based ammonium nitrate explosives. The difference from Example 1 is that after the diesel is injected, there is no penetration waiting time; the biodiesel nozzle is opened only after a 2-second interval. The rest is the same as in Example 1.

[0053] Comparative Example 7 This comparative example is based on the scheme described in Example 1 of Chinese Patent Publication No. CN102320904A. At room temperature, biodiesel and light diesel oil are mixed in any proportion to partially replace light diesel oil or engine oil. Explosives are produced by mixing biodiesel at room temperature with light diesel oil and engine oil in a weight ratio of 6.0% oil and 94.0% porous granular ammonium nitrate. The heating temperature of the biodiesel is controlled at 40°C.

[0054] Comparative Example 8 This comparative example follows the scheme described in Example 1 of Chinese Patent Publication No. CN119241321A. The safe and environmentally friendly porous granular ammonium nitrate explosive is prepared from 30 kg of cashew nut shell oil and its derivatives and 970 kg of porous granular ammonium nitrate, specifically prepared as follows: S1: Accurately weigh the biomass oilseeds and porous ammonium nitrate according to the above-mentioned mass; S2: Add porous granular ammonium nitrate to a device with a stirrer, and add cashew shell oil and its derivatives to a device with heating and spray feeding functions; S3: Heat cashew shell oil and its derivatives to 25°C, and simultaneously turn on the device stirring and device spray feeding switch. After thorough mixing, porous granular ammonium frying explosive is obtained.

[0055] To verify the technical effect of the present invention, the performance of biodiesel compound ammonium nitrate explosives of Examples 1-4 and Comparative Examples 1-8 were tested on-site according to the following methods.

[0056] Experimental Example 1 According to GB / T 13228-2015 "Method for Determination of Detonation Velocity of Industrial Explosives", the prepared explosive sample was loaded into a paper tube with a diameter of 90 mm and a charge length of 500 mm. The explosive was detonated using an electric detonator. The time it took for the detonation wave to travel the distance between two target lines was recorded using a detonation velocity meter. The detonation velocity was calculated. Each group of samples was tested 3 times and the arithmetic mean was taken.

[0057] Experimental Example 2 According to GB / T 12440-1990 "Test for the Brutality of Explosives - Lead Compression Method", the lead compression method was adopted. The lead column size was Φ60mm×60mm, the explosive charge was 50g, and No. 8 detonator was used for detonation. The compression of the lead column was measured. Each group was tested 3 times and the arithmetic mean was taken.

[0058] Experimental Example 3 The oxygen balance (OB, %) is calculated based on the molecular formula or empirical formula of the explosive. The calculation formula is as follows:

[0059] Where O, C, and H are the atomic molar numbers of oxygen, carbon, and hydrogen in the explosive, respectively, and M is the mass of the explosive in grams. For mixed systems, the mass is weighted according to the mass of each component.

[0060] Experiment Example 4 The prepared explosive samples were placed in sealed plastic bags and stored at room temperature for 15 days. Samples were taken every 5 days, and the detonation velocity was tested according to the above method. The trend of detonation velocity change and whether there was clumping or oil seepage on the particle surface were observed.

[0061] Experimental Example 5 The sample was placed in a humidity chamber with a relative humidity of 80% and a temperature of 25℃ for 7 days. After removal, the detonation velocity was measured according to Experiment 1, and the detonation velocity retention rate was calculated using the formula shown below:

[0062] Where R is the detonation velocity retention rate; V0 is the initial detonation velocity; V t The burst speed after storage for t days.

[0063] Example 6 The ultimate detonation charge method was adopted. The sample was loaded into a paper tube and detonated with No. 8 detonators of different charges. The detonation sensitivity was characterized by the minimum detonator charge that could stably detonate the sample. The smaller the value, the higher the sensitivity.

[0064] The samples from Examples 1-5 and Comparative Examples 1-8 were tested according to the methods of Experimental Examples 1-6, and the results are shown in Table 1 and 2. Figure 1-3 As shown.

[0065] Table 1. Explosion performance and storage stability test results of each embodiment and comparative example.

[0066] From the data in Table 1, the detonation velocity of Example 1 was 4520 m / s and the saturation was 20.1 mm; the detonation velocity of Example 5 was 4380 m / s and the saturation was 19.2 mm, with a difference of approximately 3.2% and 4.7% respectively. Regarding the maximum initiating charge, Example 1 used 290 mg, while Example 5 used 320 mg. The moisture resistance was 96% for Example 1 and 91% for Example 5. After 15 days of storage, the detonation velocity decayed to 30 m / s for both. Comparing Example 1 with Comparative Examples 3 and 5 reveals that, under incorrect timing, the addition of the modifier resulted in lower performance than Example 5. This indicates that the modifier must be added in the order of diesel fuel followed by biodiesel to exert a positive effect; incorrect timing can interfere with diesel fuel penetration and produce negative effects. The difference between Example 1 and Example 5 shows that the addition of the hydrophobic modifier had a measurable impact on detonation velocity, saturation, initiation sensitivity, and moisture resistance.

[0067] The detonation velocity and saturation of Example 5 were 4380 m / s and 19.2 mm, respectively; those of Comparative Example 1 were 4050 m / s and 17.2 mm, with a difference of approximately 8.1% and 11.6%; those of Comparative Example 2 were 3650 m / s and 14.8 mm, with a difference of approximately 20.0% and 29.7%; those of Comparative Example 7 were 3735 m / s and 15.0 mm, with a difference of approximately 17.3% and 28.0%; and those of Comparative Example 8 were 3800 m / s and 15.5 mm, with a difference of approximately 15.3% and 23.9%.

[0068] In Example 4, the detonation velocity increased with temperature from 25°C to 35°C, reaching 4380 m / s at 35°C; it decreased to 4300 m / s at 40°C and to 4200 m / s at 45°C, and slight oil seepage occurred after storage.

[0069] The detonation velocity of Comparative Example 3 was 3920 m / s, and that of Comparative Example 5 was 3860 m / s, both lower than that of Example 5 (4380 m / s). The detonation velocity of Comparative Example 6 was 4020 m / s, also lower than that of Example 5.

[0070] The detonation velocities of Comparative Examples 7 and 8 were 3735 m / s and 3800 m / s, respectively; the saturation was 15.0 mm and 15.5 mm, respectively; the maximum initiation charge was 520 mg and 510 mg, respectively; the detonation velocity decay after 15 days of storage was 255 m / s and 240 m / s, respectively; and the moisture resistance was 67% and 71%, respectively. The corresponding values ​​for Example 1 were 4520 m / s, 20.1 mm, 290 mg, 30 m / s decay, and 96%, respectively.

[0071] The detonation velocities of Examples 2 and 3 were 4350 m / s and 4320 m / s, respectively, both lower than the 4520 m / s of Example 1.

[0072] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A process for on-site mixing and loading of biodiesel-based ammonium nitrate explosives, characterized in that, Includes the following steps: S1: The porous granular ammonium nitrate is continuously conveyed. Light diesel oil is sprayed into the porous granular ammonium nitrate at the front end of the conveyor, so that it can preferentially penetrate into the internal micropores of the porous granular ammonium nitrate particles. After the light diesel oil is sprayed, it undergoes a penetration time of 8-20 seconds. S2: In the later stage of transportation, preheated biodiesel to 30℃-40℃ is sprayed into porous granular ammonium nitrate, so that it adheres to the outer surface of the particles to form an oxygen-rich combustion layer; the biodiesel is premixed with a hydrophobic modifier.

2. The on-site mixing process for biodiesel-based compound ammonium nitrate explosives according to claim 1, characterized in that: The amount of light diesel oil injected accounts for 2.5%-3.5% of the total mass of the explosive, the amount of biodiesel injected accounts for 2.0%-3.0% of the total mass of the explosive, and the amount of porous granular ammonium nitrate accounts for 94%-95% of the total mass of the explosive.

3. The on-site mixing process for biodiesel-based compound ammonium nitrate explosives according to claim 1, characterized in that: The light diesel oil is selected from commercially available No. 0 or No. -10 light diesel oil.

4. The on-site mixing process for biodiesel-based compound ammonium nitrate explosives according to claim 1, characterized in that: The hydrophobic modifier is selected from one or more of silane coupling agents, surfactants, and nanoparticles.

5. The on-site mixing process for biodiesel-based compound ammonium nitrate explosives according to claim 4, characterized in that: The amount of the nanoparticles added accounts for 0.5%-2.0% of the biodiesel mass.

6. The on-site mixing process for biodiesel-based compound ammonium nitrate explosives according to claim 4, characterized in that: The amount of surfactant added is 0.3%-1.5% of the biodiesel mass.

7. The on-site mixing process for biodiesel-based ammonium nitrate explosives according to claim 4, characterized in that: The amount of the silane coupling agent added is 0.3%-1.2% of the biodiesel mass.

8. The on-site mixing process for biodiesel-based compound ammonium nitrate explosives according to claim 1, characterized in that: The biodiesel is ester-based biodiesel, which is a fatty acid methyl ester or ethyl ester produced by transesterification of vegetable oil, animal oil, waste oil or microbial oil.

9. The on-site mixing process for biodiesel-based compound ammonium nitrate explosives according to claim 1, characterized in that: The injection point of the light diesel oil is located 0.3m-1.0m from the feed inlet at the front end of the screw conveyor; the injection point of the biodiesel is located 1.5m-3.5m downstream of the injection point of the light diesel oil.

10. The on-site mixing process for biodiesel-based compound ammonium nitrate explosives according to claim 1, characterized in that: The injection pressure for transporting light diesel oil is 0.2-0.6 MPa; the injection pressure for transporting biodiesel is 0.6-1.0 MPa.

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