Powdery emulsion explosive taking eutectic inorganic salt as internal phase and preparation method thereof

Abstract

The invention discloses a powdery emulsion explosive with eutectic inorganic salt as an internal phase and a preparation method, and relates to the technical field of powdery emulsion explosives, the powdery emulsion explosive comprises the following raw materials by weight: 90-110 parts of eutectic inorganic salt and 5-7 parts of a composite oil phase; wherein the eutectic inorganic salt is prepared by recrystallizing ammonium nitrate and sodium chloride. Ammonium nitrate and sodium chloride are combined in a recrystallization manner, so that sodium chloride is uniformly distributed in ammonium nitrate crystals in a lattice doping manner, a molecular-level dispersion effect is realized, and the flame inhibitor is more uniformly dispersed in an inner phase; secondly, the eutectic inorganic salt has a synergistic decomposition peak at 210-240 DEG C, and chloride ions are released in advance to interact with active groups generated by explosion; under the combined action of the two factors, sodium chloride is used as a flame inhibitor to play a role more effectively at the flame front, the flame temperature is reduced, and flame propagation is inhibited.

Description

Technical Field

[0001] The present invention relates to the technical field of powdered emulsion explosives, in particular to a powdered emulsion explosive with a eutectic inorganic salt as an internal phase and a preparation method thereof. Background Art

[0002] The application of permissible powdered emulsion explosives for coal mines stems from the multiple demands for safety, efficiency, and environmental adaptability in underground coal mines. The formulation of permissible explosives for coal mines not only meets the explosive power requirements for coal mine blasting projects, but also considers the safety of explosions in environments containing gas and combustible dust. This resolves the conflict between gas / coal dust explosion risks and efficient blasting, making them an indispensable blasting material in highly gassy mines.

[0003] The current powdered emulsion explosives permitted for use in coal mines are water-in-oil emulsions, consisting of an aqueous oxidizer solution as the internal phase and an organic fuel and emulsifier as the composite oil phase. Sodium chloride is often added to this internal phase as a flame extinguisher. The high temperature generated at the moment of explosive detonation vaporizes the sodium chloride, which absorbs heat as it vaporizes and reacts with the active free radicals generated by the explosion, thereby lowering the flame temperature and inhibiting flame propagation. However, in explosives production, mechanical stirring of the sodium chloride after addition to the aqueous oxidizer solution results in uneven sodium chloride dispersion in the internal phase of the finished explosive, leading to localized flame extinguisher deficiency. Furthermore, sodium chloride's high vaporization temperature (above 1400°C) weakens its flame-extinguishing effectiveness.

[0004] When preparing the internal phase of powdered emulsion explosives permitted for use in coal mines, 4% to 7% water is typically added. This low water content requires the internal phase to be heated to above 130°C during the emulsion matrix preparation process. Otherwise, substances such as ammonium nitrate, sodium nitrate, and sodium chloride cannot fully dissolve in the water. Excessively high internal phase preparation temperatures not only compromise the intrinsic safety of explosives during large-scale industrial production but also increase energy consumption during the heating process.

[0005] Unlike finished emulsion explosives or on-site mixed emulsion explosives, powdered emulsion explosives require the internal phase to crystallize and solidify quickly because of its solid state. The faster the crystallization and solidification speed, the higher the production efficiency. If the water content in the internal phase increases, the crystallization speed will be reduced, affecting the solidification effect.

[0006] When preparing the external phase, the composite oil phase material must be heated to a temperature above 120°C. The heating temperature of the composite oil phase material should be close to that of the internal phase solution to prevent the internal phase from entering the composite oil phase due to a large temperature difference, causing the internal phase temperature to drop and causing solute precipitation in the aqueous solution. Furthermore, heating the composite oil phase material to a higher temperature not only reduces the emulsification efficiency of the emulsifier in the composite oil phase, but also consumes more energy for heating and reduces the inherent safety of the explosives production process. Summary of the Invention

[0007] Based on the technical problems existing in the background art, the present application provides a powdered emulsion explosive with eutectic inorganic salt as an internal phase and a preparation method, which has low energy consumption in the preparation process, high intrinsic safety, simple explosive preparation process, low raw material cost, good flame-out effect, large power, and can be applied to coal mine blasting engineering in underground coal mines.

[0008] The present application provides a powdered emulsion explosive with eutectic inorganic salt as an internal phase, which comprises the following raw materials in parts by weight: eutectic inorganic salt 90-110 parts, composite oil phase 5-7 parts.

[0009] The eutectic inorganic salt is prepared by recrystallization of ammonium nitrate and sodium chloride.

[0010] Preferably, the mass ratio of ammonium nitrate to sodium chloride in the eutectic inorganic salt is 1:0.1-0.15.

[0011] Preferably, the composite oil phase comprises the following raw materials in parts by weight: solid paraffin 1-3 parts, microcrystalline wax 1-3 parts, emulsifier 1-2 parts.

[0012] Preferably, the emulsifier is a polyisobutylene succinimide emulsifier or a polyisobutylene succinic anhydride emulsifier.

[0013] The present application provides a preparation method of a powdered emulsion explosive with eutectic inorganic salt as an internal phase, and the powdered emulsion explosive is as described above, and the method steps are as follows:

[0014] S1: Dissolve ammonium nitrate and sodium chloride in water and recrystallize to obtain eutectic inorganic salt;

[0015] S2: Heat treatment of eutectic inorganic salt to obtain molten eutectic inorganic salt;

[0016] S3: Sequentially add the composite oil phase and the molten eutectic inorganic salt into the emulsifier for emulsification to obtain an emulsion matrix;

[0017] S4: After the emulsion matrix is cooled, crystallized and solidified, the emulsion matrix is stirred to form a powder, and the powder is sieved and loaded with explosives to obtain a coal mine permissible powdered emulsion explosive with molten eutectic inorganic salt as an internal phase.

[0018] Preferably, the temperature of water in S1 is 60-80℃.

[0019] Preferably, the temperature of heating treatment in S2 is 105-115℃.

[0020] Preferably, the emulsification time in S3 is 3-5min.

[0021] The present application provides the above-mentioned powdered emulsion explosive with eutectic inorganic salt as an internal phase for use in coal mine blasting engineering in underground coal mines.

[0022] Beneficial technical effects of the present invention:

[0023] (1) The present invention enhances the flame extinguishing effect of sodium chloride. First, unlike the traditional simple mechanical stirring, ammonium nitrate and sodium chloride are combined in a recrystallization manner, so that sodium chloride is evenly distributed in the ammonium nitrate crystal in the form of lattice doping, achieving a molecular-level dispersion effect, making the flame extinguisher more evenly dispersed in the internal phase; secondly, compared with the melting temperature (about 700°C) and vaporization temperature (above 1400°C) of sodium chloride element, the eutectic prepared by ammonium nitrate and sodium chloride in a certain proportion in the present invention has a synergistic decomposition peak at 210°C-240°C (C80 data, Figure 2 Peak E (the peak of the synergistic decomposition exotherm of the eutectic) releases chloride ions in advance, interacting with the reactive groups generated by the explosion. These two factors work together to make sodium chloride a more effective flame suppressant at the flame front, lowering flame temperature and inhibiting flame propagation.

[0024] (2) The present invention reduces the heating temperature for the preparation of explosives. The composite salt formed by recrystallization of ammonium nitrate and sodium chloride in a certain proportion is heated to a molten state as the dispersed phase of the explosive. It only needs to be heated to 105-115°C (C80 data, Figure 2 Peak D is the melting peak of the eutectic. Figure 3 The melting peak D of standard ammonium nitrate is approximately 175°C, indicating that ammonium nitrate and sodium chloride form a new low-melting eutectic during the recrystallization process during pretreatment. However, in the current preparation of powdered emulsion explosives permitted for coal mining, the dispersed phase must be heated to above 130°C to completely dissolve the ammonium nitrate, sodium nitrate, and sodium chloride in the solution due to the low water content. Lowering the dispersed phase heating temperature not only improves the intrinsic safety of the explosives preparation process but also saves energy.

[0025] (3) The present invention accelerates the crystallization and solidification of the internal phase of the powdered emulsion explosive. Compared with the current powdered emulsion explosive formula permitted for use in coal mines, the explosive formula of the present invention contains no moisture, which results in a faster crystallization of the emulsion matrix. Complete crystallization and solidification can be achieved in approximately 20 minutes, shortening the overall preparation time of the explosive. Furthermore, the emulsion matrix has a better solidification effect, which helps improve the overall quality of the powder.

[0026] (4) The application reduces the heating temperature of the preparation of the composite oil phase. The solid paraffin, microcrystalline wax, polyisobutylene succinimide or polyisobutylene succinic anhydride emulsifier is mixed in a certain proportion and then heated to 95-105 DEG C as the external phase. The temperature difference between the internal phase and the external phase at this temperature is small, which avoids the precipitation of solutes in the internal phase when the dispersed phase solution enters the continuous phase due to the large temperature difference. Compared with the current heating temperature (more than 120 DEG C) of the composite oil phase in the preparation process of the coal mine permissible powdered emulsion explosive, the lower heating temperature of the composite oil phase can improve the emulsification efficiency of the emulsifier and improve the quality of the emulsion matrix. The lower heating temperature of the composite oil phase can not only improve the intrinsic safety in the explosive production process, but also save energy and reduce emissions. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The preparation process flow chart of the powdered emulsion explosive with the eutectic inorganic salt as the internal phase is provided for the application.

[0028] Figure 2 The C80 heat flow curve diagram of the eutectic inorganic salt is provided for the application.

[0029] Figure 3 The C80 heat flow curve diagram of the ammonium nitrate is provided for the application. DETAILED DESCRIPTION

[0030] The application will be further described below in combination with specific examples.

[0031] Example 1

[0032] The formula of the industrial production of 100 kg of the coal mine permissible powdered emulsion explosive with the eutectic composite salt as the internal phase in a molten state is: ammonium nitrate 85 kg, sodium chloride 9 kg, and composite oil phase 6 kg. Among them: the composite oil phase is solid paraffin 3 kg, microcrystalline wax 2 kg, and polyisobutylene succinimide 1 kg.

[0033] Reference Figure 1 According to the above components and mass ratio, the preparation operation steps are as follows:

[0034] Firstly, 85 kg of ammonium nitrate and 9 kg of sodium chloride are weighed, dissolved in water, recrystallized, and then 94 kg of eutectic composite salt is obtained and added to a ball mill for pulverization.

[0035] Secondly, the powdered composite salt is heated to 105-115 DEG C to obtain the molten eutectic composite salt as the internal phase.

[0036] Thirdly, the solid paraffin 3 kg, microcrystalline wax 2 kg, and polyisobutylene succinimide 1 kg are mixed and heated to 95-105 DEG C to obtain the composite oil phase.

[0037] In the fourth step, under the shearing action of the emulsifier, the molten eutectic composite salt is slowly added to the composite oil phase and the emulsification is continued for 3-5 minutes to obtain an emulsified matrix.

[0038] In the fifth step, after the emulsified matrix is ​​cooled, crystallized and solidified, it is made into powder by low-speed stirring, sieved and then charged, thereby obtaining a powdered emulsion explosive for coal mines with a molten eutectic composite salt as an internal phase.

[0039] Example 2

[0040] The formula for industrial production of 100 kg of a powdered emulsion explosive for coal mining with a molten eutectic complex salt as the internal phase is: 84 kg of ammonium nitrate, 9 kg of sodium chloride, and 7 kg of a composite oil phase. The composite oil phase consists of 4 kg of solid paraffin, 2 kg of microcrystalline wax, and 1 kg of polyisobutylene succinic anhydride.

[0041] Reference Figure 1 According to the above components and mass ratios, the preparation steps are as follows:

[0042] In the first step, 85 kg of ammonium nitrate and 9 kg of sodium chloride were weighed, added to water and fully dissolved and then recrystallized to obtain 94 kg of eutectic composite salt, which was added to a ball mill and fully crushed.

[0043] In the second step, the powdered composite salt is heated to 105° C.-115° C. to obtain a molten eutectic composite salt as an inner phase.

[0044] In the third step, 4 kg of solid paraffin wax, 2 kg of microcrystalline wax, and 1 kg of polyisobutylene succinic anhydride were weighed, mixed, and heated to 95° C.-105° C. to prepare a composite oil phase.

[0045] In the fourth step, under the shearing action of the emulsifier, the molten eutectic composite salt is slowly added to the composite oil phase and the emulsification is continued for 3-5 minutes to obtain an emulsified matrix.

[0046] In the fifth step, after the emulsified matrix is ​​cooled, crystallized and solidified, it is made into powder by low-speed stirring, sieved and then charged, thereby obtaining a powdered emulsion explosive for coal mines with a molten eutectic composite salt as an internal phase.

[0047] Example 3

[0048] The formula for industrial production of 100 kg of a powdered emulsion explosive for coal mining with a molten eutectic complex salt as the internal phase is: 83 kg of ammonium nitrate, 10 kg of sodium chloride, and 7 kg of a composite oil phase. The composite oil phase consists of 3 kg of solid paraffin wax, 3 kg of microcrystalline wax, and 1 kg of polyisobutylene succinic anhydride.

[0049] Reference Figure 1 According to the above components and mass ratios, the preparation steps are as follows:

[0050] In the first step, 85 kg of ammonium nitrate and 9 kg of sodium chloride were weighed, added to water and fully dissolved and then recrystallized to obtain 94 kg of eutectic composite salt, which was added to a ball mill and fully crushed.

[0051] In the second step, the powdered composite salt is heated to 105° C.-115° C. to obtain a molten eutectic composite salt as an inner phase.

[0052] In the third step, 3 kg of solid paraffin wax, 3 kg of microcrystalline wax, and 1 kg of polyisobutylene succinic anhydride were weighed, mixed, and heated to 95° C.-105° C. to prepare a composite oil phase.

[0053] In the fourth step, under the shearing action of the emulsifier, the molten eutectic composite salt is slowly added to the composite oil phase and the emulsification is continued for 3-5 minutes to obtain an emulsified matrix.

[0054] In the fifth step, after the emulsified matrix is ​​cooled, crystallized and solidified, it is made into powder by low-speed stirring, sieved and then charged, thereby obtaining a powdered emulsion explosive for coal mines with a molten eutectic composite salt as an internal phase.

[0055] The properties of the products prepared in Examples 1-3 are shown in Table 1. The detonation velocity test method references the standard number GB / T 13228-2015. The force test method references the standard number GB / T 12440-1990. The impact sensitivity test method references the standard number WJ / T 9038.1-2004. The friction sensitivity test method references the standard number WJ / T 9052.1-2006.

[0056] Table 1 Properties of powdered emulsion explosives

[0057] index Example 1 Example 2 Example 3 <![CDATA[炸药密度(g / m 3 )]]> 1.40 1.40 1.42 <![CDATA[装药密度(g / m 3 )]]> 0.90 0.90 0.90 Explosive speed (m / s) 3280 3172 2926 Sharpness (mm) 10.3 10.0 9.2 Impact sensitivity 0% chance of ignition 0% chance of ignition 0% chance of ignition friction sensitivity 0% chance of ignition 0% chance of ignition 0% chance of ignition

[0058] The test results in Table 1 show that as the content of sodium chloride, an inert substance, in the explosives gradually increases, the detonation velocity and force of the explosives decrease, but the decrease is small, indicating that the sodium chloride content has little effect on the explosive's power. The impact and friction sensitivities remain constant and zero for all three example explosive formulations, indicating low mechanical sensitivity and high safety.

[0059] Figure 2 and Figure 3The C80 heat flow curves for eutectic inorganic salts and ammonium nitrate, respectively, were measured from room temperature to 300°C at a heating rate of 0.8°C / min in air. Recrystallization of ammonium nitrate and sodium chloride in a specific ratio yields a low-melting-point eutectic with a melting point of approximately 110°C, which is approximately 60°C lower than the melting point of ammonium nitrate (170°C) and lower than the internal heating temperature (above 130°C) currently used in the preparation of permissible emulsion explosives for coal mines. The decomposition exothermic peak temperature of ammonium nitrate is approximately 285°C, while the decomposition exothermic peak of the recrystallized product of sodium nitrate and sodium chloride is approximately 220°C, a decrease of approximately 65°C. This facilitates the early release of chloride ions and enhances the flame extinguishing effect.

[0060] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents, and all should be included in the scope of protection of the present application.

Claims

1. A powdered emulsion explosive with a eutectic inorganic salt as an internal phase, characterized in that: The raw materials include the following parts by weight: 90-110 parts of eutectic inorganic salt and 5-7 parts of composite oil phase; Wherein, the eutectic inorganic salt is prepared by recrystallization of ammonium nitrate and sodium chloride.

2. The powdered emulsion explosive with eutectic inorganic salt as internal phase according to claim 1, characterized in that: The mass ratio of ammonium nitrate to sodium chloride in the eutectic inorganic salt is 1:0.1-0.

15.

3. The powdered emulsion explosive with eutectic inorganic salt as internal phase according to claim 1, characterized in that The composite oil phase comprises the following raw materials in parts by weight: 1-3 parts of solid paraffin, 1-3 parts of microcrystalline wax, and 1-2 parts of emulsifier.

4. The powdered emulsion explosive with eutectic inorganic salt as internal phase according to claim 3, characterized in that: The emulsifier is a polyisobutylene succinimide emulsifier or a polyisobutylene succinic anhydride emulsifier.

5. A method for preparing a powdered emulsion explosive with a eutectic inorganic salt as an internal phase, wherein the powdered emulsion explosive is as described in any one of claims 1 to 4, characterized in that: The steps are as follows: S1: dissolving ammonium nitrate and sodium chloride in water and recrystallizing to obtain a eutectic inorganic salt; S2: heating the eutectic inorganic salt to obtain a molten eutectic inorganic salt; S3: sequentially adding the composite oil phase and the molten eutectic inorganic salt into an emulsifier for emulsification to prepare an emulsified matrix; S4: After the emulsion matrix is ​​cooled, crystallized and solidified, the emulsion matrix is ​​stirred to form a powder, which is sieved and then charged to obtain a powdered emulsion explosive for coal mines with a molten eutectic inorganic salt as an internal phase.

6. The method for preparing a powdered emulsion explosive with a eutectic inorganic salt as an internal phase according to claim 5, characterized in that: The temperature of water in S1 is 60-80℃.

7. The method for preparing a powdered emulsion explosive with a eutectic inorganic salt as an internal phase according to claim 5, characterized in that: The temperature of the heating treatment in S2 is 105-115°C.

8. The method for preparing a powdered emulsion explosive with a eutectic inorganic salt as an internal phase according to claim 5, characterized in that: The emulsification time in S3 is 3-5 minutes.

9. Use of the powdered emulsion explosive with a eutectic inorganic salt as an internal phase according to any one of claims 1 to 4 in underground coal mine blasting engineering.

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