Rock expanded ammonium nitrate explosive and preparation method thereof

Abstract

The invention discloses a rock expanded ammonium nitrate explosive and a preparation method thereof, and relates to the technical field of explosives, the rock expanded ammonium nitrate explosive comprises the following raw materials by weight: 70-90 parts of ammonium nitrate, 3-5 parts of a composite oil phase, 3-5 parts of wood flour, 8-12 parts of porous granular ammonium nitrate, and 0.01-0.1 part of an expanding agent; the swelling agent consists of microcrystalline wax, calcium stearate, a polyoxyethylene ether surfactant and a quaternary ammonium salt surfactant; the preparation method of the rock expanded ammonium nitrate explosive comprises the following steps: mixing ammonium nitrate with water to obtain a water phase; and mixing and puffing the water phase, the composite oil phase and the swelling agent, adding the wood flour and the porous granular ammonium nitrate, and uniformly mixing to obtain the rock expanded ammonium nitrate explosive. Through the design of the swelling agent, the free-running property and the viscosity of the rock expanded ammonium nitrate explosive are considered, and the powder return rate of the rock expanded ammonium nitrate explosive in the upward hole charging process is reduced.

Description

Technical Field

[0001] This invention relates to the field of explosives technology, and in particular to rock-expanded ammonium nitrate explosives and their preparation methods. Background Technology

[0002] Expanded ammonium nitrate explosives are widely used in rock blasting in open-pit mines, tunnels, and infrastructure projects. When used in complex charging conditions such as upward-facing holes, the explosives not only need to have sustainable detonation performance, but also need to be adaptable to the construction and loading process, such as "dispersion", "controllable adhesion" and "not easy to return to dust".

[0003] Existing rock-expanded ammonium nitrate explosives generally face the contradiction of "difficulty in balancing flowability and viscosity" when loaded into upward holes: on the one hand, in order to achieve continuous pumping, filling or free-flowing filling, the system needs to maintain a certain degree of flowability to avoid bridging or blockage at the delivery pipeline or orifice; on the other hand, upward hole loading requires the explosive to have sufficient viscosity or structure retention capacity after entering the hole to resist gravity fall, air disturbance in the hole and the influence of dust / debris on the hole wall, and reduce material scattering, slippage and stratification during the loading process.

[0004] Therefore, there is an urgent need to develop a rock-expanded ammonium nitrate explosive to better meet the comprehensive requirements of "dispersibility-viscosity-low powder return rate" in working conditions such as upward hole charging. Summary of the Invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes rock-expanded ammonium nitrate explosive and its preparation method. By designing the expansion agent, the flowability and viscosity of the rock-expanded ammonium nitrate explosive are balanced, and the return powder rate of the rock-expanded ammonium nitrate explosive during the upward hole loading process is reduced.

[0006] The present invention proposes a rock-expanded ammonium nitrate explosive, comprising the following raw materials in parts by weight: 70-90 parts ammonium nitrate, 3-5 parts composite oil phase, 3-5 parts wood flour, 8-12 parts porous granular ammonium nitrate, and 0.01-0.1 parts expansion agent;

[0007] The swelling agent is composed of microcrystalline wax, calcium stearate, polyoxyethylene ether surfactant, and quaternary ammonium salt surfactant.

[0008] Preferably, the mass ratio of the microcrystalline wax, calcium stearate, polyoxyethylene ether surfactant, and quaternary ammonium salt surfactant is 1:1-3:1-2:1-2.

[0009] Preferably, the polyoxyethylene ether surfactant is prepared as follows: fatty alcohol is etherified with ethylene oxide under the action of a catalyst, then esterified with maleic anhydride, and finally sulfonated with sodium sulfite to obtain the polyoxyethylene ether surfactant.

[0010] Preferably, the fatty alcohol comprises the following components in molar percentage: lauryl alcohol 40%-60%, myristyl alcohol 15%-25%, palmitol 10%-20%, and stearyl alcohol 10%-20%.

[0011] Preferably, the molar ratio of fatty alcohol, ethylene oxide, maleic anhydride and sodium sulfite is 1:0.8-1:0.8-1:0.9-1.

[0012] Preferably, the etherification reaction conditions are: temperature 80-90℃, time 4-6h;

[0013] And / or, the conditions for esterification reaction are: temperature 70-90℃, time 6-18h;

[0014] And / or, the sulfonation reaction conditions are: temperature 100-110℃, time 4-8h.

[0015] Preferably, the quaternary ammonium salt surfactant is prepared as follows: lactobionic acid and N,N-dimethyldipropylenetriamine are refluxed in a solvent for 12-36 hours, and the intermediate product is then refluxed with bromooctane in a solvent for 40-50 hours to obtain the quaternary ammonium salt surfactant.

[0016] Preferably, the molar ratio of lactobionic acid to N,N-dimethyldipropylenetriamine is 1:1-1.5.

[0017] Preferably, the molar ratio of the intermediate product to bromooctane is 1:2-4.

[0018] The present invention proposes a method for preparing rock-expanded ammonium nitrate explosive, which is as described above. The method steps are as follows: ammonium nitrate is mixed with water to obtain an aqueous phase; then the aqueous phase, composite oil phase and expanding agent are mixed and expanded; then wood flour and porous granular ammonium nitrate are added and mixed evenly to obtain rock-expanded ammonium nitrate explosive.

[0019] Beneficial technical effects of the present invention:

[0020] The polyoxyethylene ether surfactant introduced into the swelling agent in this invention has a "gradient lipophilic" characteristic in its hydrophobic segments, which can simultaneously match the wetting requirements of different polarity / viscosity components in the composite oil phase; the hydrophilic end simultaneously possesses a hydration layer of EO segments and a strong hydrophilic group of sulfonate. This structure enables it to maintain effective interfacial activity and adsorption stability in the high ionic strength ammonium nitrate aqueous phase, and can form a denser and more elastic interfacial film in the "aqueous phase / composite oil phase" and "aqueous phase / ammonium nitrate particle surface", thereby obtaining more uniform microbubble nucleation and a more stable bubble film during the swelling stage, reducing the risk of bubble aggregation and collapse. Therefore, controllable swelling and viscosity establishment of the system can be achieved at a low addition amount, avoiding "agglomeration, clogging, and decreased fluidity" caused by simply relying on solid thickening.

[0021] This invention further designs a lactobionic quaternary ammonium salt surfactant: its polar head group is rich in hydroxyl / amide / amine groups and quaternary ammonium positive charge, exhibiting significant hydration and multi-site interaction capabilities, and can form a strongly adsorbed wetting-coating layer on the surface of ammonium nitrate (including porous granular ammonium nitrate); at the same time, the introduced alkyl segments can act as hydrophobic anchoring points, synergistically associating with the hydrophobic phase structure formed by the composite oil phase and microcrystalline wax / calcium stearate. This transforms the solid particle surface from a state of "dry, easily pulverized, and easily abraded" to a state of "directionally wetted surface with weak adhesion," significantly improving inter-particle contact behavior, reducing the tendency for dust formation and particle rebound during loading, and inhibiting the separation of wood flour / porous granular ammonium nitrate during mixing and transportation.

[0022] Furthermore, the anionic / cationic head groups of the polyoxyethylene ether surfactant and the quaternary ammonium salt surfactant of this invention make the micelles / aggregates more compact through electrostatic association. The EO hydration layer and the sugar acid polyhydroxy hydration layer together construct a high-strength hydration shell, enabling the aggregates to remain stable in a high-salt environment. At the same time, the mixed aggregates are more likely to form a "network-like / worm-like" structure with a certain degree of elasticity, giving the system typical shear thinning (easy to flow during filling) + static rebound (not easy to collapse in the pores) rheological characteristics. Thus, the expanded ammonium nitrate explosive maintains good flowability under shear conditions during transportation / filling, and quickly recovers a certain apparent viscosity and structural retention force after entering the pores, solving the contradiction in the prior art of "sacrificing flowability for viscosity / severe powder return for flowability". Detailed Implementation

[0023] The present invention will be further explained below with reference to specific embodiments.

[0024] Example 1

[0025] Ammonium nitrate is mixed with water to obtain an aqueous phase; then the aqueous phase, a commercially available composite oil phase, and an expanding agent are mixed and expanded, and wood flour and porous granular ammonium nitrate are added and mixed evenly to obtain rock-expanded ammonium nitrate explosive.

[0026] The rock-expanded ammonium nitrate explosive contains the following raw materials in parts by weight: 80 parts ammonium nitrate, 4 parts composite oil phase, 4 parts wood flour, 10 parts porous granular ammonium nitrate, and 0.05 parts expanding agent.

[0027] The swelling agent is composed of microcrystalline wax, calcium stearate, polyoxyethylene ether surfactant and quaternary ammonium salt surfactant in a mass ratio of 1:2:1.5:1.5.

[0028] The preparation method of polyoxyethylene ether surfactant is as follows: fatty alcohol is etherified with ethylene oxide under the action of a catalyst, then esterified with maleic anhydride, and finally sulfonated with sodium sulfite to obtain polyoxyethylene ether surfactant.

[0029] The fatty alcohol comprises the following components in molar percentage: lauryl alcohol 50%, myristyl alcohol 20%, palmitol 15%, and stearyl alcohol 15%; the catalyst is potassium hydroxide, added at 2% of the total mass of the fatty alcohol; the molar ratio of fatty alcohol, ethylene oxide, maleic anhydride, and sodium sulfite is 1:0.9:0.9:0.95; the etherification reaction conditions are: temperature 85℃, time 5h; the esterification reaction conditions are: temperature 80℃, time 12h; and the sulfonation reaction conditions are: temperature 105℃, time 6h.

[0030] The preparation method of quaternary ammonium salt surfactant is as follows: lactobionic acid and N,N-dimethyldipropylenetriamine are refluxed in a solvent for 24 h, and the intermediate product is then refluxed with bromooctane in a solvent for 45 h to obtain quaternary ammonium salt surfactant.

[0031] The molar ratio of lactobionic acid to N,N-dimethyldipropylenetriamine is 1:1.2; the molar ratio of the intermediate product to bromooctane is 1:3.

[0032] Example 2

[0033] Ammonium nitrate is mixed with water to obtain an aqueous phase; then the aqueous phase, a commercially available composite oil phase, and an expanding agent are mixed and expanded, and wood flour and porous granular ammonium nitrate are added and mixed evenly to obtain rock-expanded ammonium nitrate explosive.

[0034] The rock-expanded ammonium nitrate explosive contains the following raw materials in parts by weight: 70 parts ammonium nitrate, 3 parts composite oil phase, 3 parts wood flour, 8 parts porous granular ammonium nitrate, and 0.01 parts expanding agent.

[0035] The swelling agent is composed of microcrystalline wax, calcium stearate, polyoxyethylene ether surfactant and quaternary ammonium salt surfactant in a mass ratio of 1:1:1:1.

[0036] The preparation method of polyoxyethylene ether surfactant is as follows: fatty alcohol is etherified with ethylene oxide under the action of a catalyst, then esterified with maleic anhydride, and finally sulfonated with sodium sulfite to obtain polyoxyethylene ether surfactant.

[0037] The fatty alcohol comprises the following components in molar percentage: lauryl alcohol 40%, myristyl alcohol 20%, palmitol 20%, and stearyl alcohol 20%; the catalyst is potassium hydroxide, added at 2% of the total mass of the fatty alcohol; the molar ratio of fatty alcohol, ethylene oxide, maleic anhydride, and sodium sulfite is 1:0.8:0.8:0.9; the etherification reaction conditions are: temperature 80℃, time 6h; the esterification reaction conditions are: temperature 70℃, time 18h; and the sulfonation reaction conditions are: temperature 100℃, time 8h.

[0038] The preparation method of quaternary ammonium salt surfactant is as follows: lactobionic acid and N,N-dimethyldipropylenetriamine are refluxed in a solvent for 12 h, and the intermediate product is then refluxed with bromooctane in a solvent for 40 h to obtain quaternary ammonium salt surfactant.

[0039] The molar ratio of lactobionic acid to N,N-dimethyldipropylenetriamine is 1:1; the molar ratio of the intermediate product to bromooctane is 1:2.

[0040] Example 3

[0041] Ammonium nitrate is mixed with water to obtain an aqueous phase; then the aqueous phase, a commercially available composite oil phase, and an expanding agent are mixed and expanded, and wood flour and porous granular ammonium nitrate are added and mixed evenly to obtain rock-expanded ammonium nitrate explosive.

[0042] The rock-expanded ammonium nitrate explosive contains the following raw materials in parts by weight: 90 parts ammonium nitrate, 5 parts composite oil phase, 5 parts wood flour, 12 parts porous granular ammonium nitrate, and 0.1 parts expanding agent.

[0043] The swelling agent is composed of microcrystalline wax, calcium stearate, polyoxyethylene ether surfactant and quaternary ammonium salt surfactant in a mass ratio of 1:3:2:2.

[0044] The preparation method of polyoxyethylene ether surfactant is as follows: fatty alcohol is etherified with ethylene oxide under the action of a catalyst, then esterified with maleic anhydride, and finally sulfonated with sodium sulfite to obtain polyoxyethylene ether surfactant.

[0045] The fatty alcohol comprises the following components in molar percentage: lauryl alcohol 60%, myristyl alcohol 15%, palmitol 15%, and stearyl alcohol 10%; the catalyst is potassium hydroxide, added at 2% of the total mass of the fatty alcohol; the molar ratio of fatty alcohol, ethylene oxide, maleic anhydride, and sodium sulfite is 1:1:1:1; the etherification reaction conditions are: temperature 90℃, time 4h; the esterification reaction conditions are: temperature 90℃, time 6h; and the sulfonation reaction conditions are: temperature 110℃, time 4h.

[0046] The preparation method of quaternary ammonium salt surfactant is as follows: lactobionic acid and N,N-dimethyldipropylenetriamine are refluxed in a solvent for 36 h, and the intermediate product is then refluxed with bromooctane in a solvent for 50 h to obtain quaternary ammonium salt surfactant.

[0047] The molar ratio of lactobionic acid to N,N-dimethyldipropylenetriamine is 1:1.5; the molar ratio of the intermediate product to bromooctane is 1:4.

[0048] Comparative Example 1

[0049] The swelling agent in this scheme is composed of microcrystalline wax, calcium stearate and polyoxyethylene ether surfactant in a mass ratio of 1:3:4, and all other conditions are the same as in Example 1.

[0050] Comparative Example 2

[0051] The swelling agent in this scheme is composed of microcrystalline wax, calcium stearate and quaternary ammonium salt surfactant in a mass ratio of 1:3:4, and all other conditions are the same as in Example 1.

[0052] Comparative Example 3

[0053] The bulking agent in this scheme is composed of microcrystalline wax and calcium stearate in a mass ratio of 1:3, and all other conditions are the same as in Example 1.

[0054] The flowability and return rate of the rock-expanded ammonium nitrate explosives prepared in Example 1 and Comparative Examples 1-3 were tested, and the test results are shown in Table 1.

[0055] Flowability is characterized by bulk density and tested according to "GJB 5891.2-2006 Test Methods for Pyrotechnic Agents";

[0056] The method for testing the angle of repose is in accordance with the "Guidelines for Determination of Powder Flowability".

[0057] Table 1 Performance test results of rock-expanded ammonium nitrate explosive

[0058]

[0059] As can be seen from the test results of Example 1 in Table 1, the bulk density of the rock-expanded ammonium nitrate explosive prepared by the present invention is 0.60 g / cm³. 3 It exhibits good flowability, and the return powder rate of the rock-expanded ammonium nitrate explosive is only 8.5%, indicating that the present invention achieves a balance between the flowability and viscosity of the rock-expanded ammonium nitrate explosive through the design of the expanding agent, thereby reducing the return powder rate of the rock-expanded ammonium nitrate explosive during the upward hole loading process.

[0060] The experimental results of Comparative Examples 1 and 3 show that the polyoxyethylene ether surfactant of the present invention can effectively reduce the powder return rate of rock-expanded ammonium nitrate explosive. This is because the hydrophobic segments of the polyoxyethylene ether surfactant exhibit a "gradient oleophilic" characteristic, which can simultaneously match the wetting requirements of different polarity / viscosity components in the composite oil phase; the hydrophilic end simultaneously possesses a hydration layer of EO segments and a strong hydrophilic group of sulfonate. This structure enables it to maintain effective interfacial activity and adsorption stability in the high ionic strength ammonium nitrate aqueous phase, and can form a denser and more elastic interfacial film in the "aqueous phase / composite oil phase" and "aqueous phase / ammonium nitrate particle surface", thereby obtaining more uniform microbubble nucleation and a more stable bubble film during the expansion stage, reducing the risk of bubble coalescence and collapse. Therefore, controllable expansion and viscosity establishment of the system can be achieved at a lower addition amount, avoiding "agglomeration, clogging, and decreased fluidity" caused by simply relying on solid thickening.

[0061] The experimental results of Comparative Examples 2 and 3 show that the lactobionic acid-based quaternary ammonium salt surfactant of the present invention can also effectively reduce the powder return rate of rock-expanded ammonium nitrate explosive. This is because its polar head group is rich in hydroxyl / amide / amine groups and quaternary ammonium positive charge, and has significant hydration and multi-point action capabilities, which can form a strongly adsorbed wetting-coating layer on the surface of ammonium nitrate (including porous granular ammonium nitrate). At the same time, the introduced alkyl segments can act as hydrophobic anchoring points, and synergistically associate with the hydrophobic phase structure formed by the composite oil phase and microcrystalline wax / calcium stearate. This transforms the surface of solid particles from a state of "dry, easy to pulverize, and easy to rub" to a state of "the surface is directionally wetted and has weak adhesion", significantly improving the contact behavior between particles, reducing the tendency of dust formation and particle rebound during the loading process, and inhibiting the separation of wood flour / porous granular ammonium nitrate during mixing and transportation.

[0062] The experimental results of Example 1 and Comparative Examples 1 and 2 show that the polyoxyethylene ether surfactant and quaternary ammonium salt surfactant in the expanding agent of the present invention have a synergistic promoting effect on improving the powder return rate of rock-expanded ammonium nitrate explosives during orifice loading, while maintaining the good flowability of the rock-expanded ammonium nitrate explosives. This is because the anionic / cationic head groups of the polyoxyethylene ether surfactant and the quaternary ammonium salt surfactant of the present invention make the micelles / aggregates more compact through electrostatic association. The EO hydration layer and the sugar acid polyhydroxy hydration layer together construct a high-strength hydration shell, which makes the aggregates remain stable in a high-salt environment. At the same time, the mixed aggregates are more likely to form a "network-like / worm-like" structure with a certain degree of elasticity, giving the system typical shear thinning (easy to flow during loading) + static rebound (not easy to collapse in the orifice) rheological characteristics. Thus, the expanded ammonium nitrate explosives maintain good flowability under the shear conditions of conveying / filling, and quickly recover a certain apparent viscosity and structural retention force after entering the orifice, solving the contradiction of "sacrificing flowability for viscosity / severe powder return for flowability" in the prior art.

[0063] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application. The scope of this application is defined by the appended claims and their equivalents, all of which should be included within the protection scope of this application.

Claims

1. A rock-expanded ammonium nitrate explosive, characterized in that, It contains the following raw materials in parts by weight: 70-90 parts ammonium nitrate, 3-5 parts composite oil phase, 3-5 parts wood flour, 8-12 parts porous granular ammonium nitrate, and 0.01-0.1 parts swelling agent; The swelling agent is composed of microcrystalline wax, calcium stearate, polyoxyethylene ether surfactant, and quaternary ammonium salt surfactant.

2. The rock-expanded ammonium nitrate explosive according to claim 1, characterized in that, The mass ratio of the microcrystalline wax, calcium stearate, polyoxyethylene ether surfactant, and quaternary ammonium salt surfactant is 1:1-3:1-2:1-2.

3. The rock-expanded ammonium nitrate explosive according to claim 1, characterized in that, The preparation method of the polyoxyethylene ether surfactant is as follows: fatty alcohol is etherified with ethylene oxide under the action of a catalyst, then esterified with maleic anhydride, and finally sulfonated with sodium sulfite to obtain the polyoxyethylene ether surfactant.

4. The rock-expanded ammonium nitrate explosive according to claim 3, characterized in that, The fatty alcohol comprises the following components in molar percentage: lauryl alcohol 40%-60%, myristyl alcohol 15%-25%, palmitol 10%-20%, and stearyl alcohol 10%-20%.

5. The rock-expanded ammonium nitrate explosive according to claim 3, characterized in that, The molar ratio of fatty alcohol, ethylene oxide, maleic anhydride and sodium sulfite is 1:0.8-1:0.8-1:0.9-1.

6. The rock-expanded ammonium nitrate explosive according to claim 3, characterized in that, The conditions for the etherification reaction are: temperature 80-90℃, time 4-6h; And / or, the conditions for esterification reaction are: temperature 70-90℃, time 6-18h; And / or, the sulfonation reaction conditions are: temperature 100-110℃, time 4-8h.

7. The rock-expanded ammonium nitrate explosive according to claim 1, characterized in that, The preparation method of the quaternary ammonium salt surfactant is as follows: lactobionic acid and N,N-dimethyldipropylenetriamine are refluxed in a solvent for 12-36 h, and the intermediate product is then refluxed with bromooctane in a solvent for 40-50 h to obtain the quaternary ammonium salt surfactant.

8. The rock-expanded ammonium nitrate explosive according to claim 7, characterized in that, The molar ratio of lactobionic acid to N,N-dimethyldipropylenetriamine is 1:1-1.

5.

9. The rock-expanded ammonium nitrate explosive according to claim 7, characterized in that, The molar ratio of the intermediate product to bromooctane is 1:2-4.

10. A method for preparing rock-expanded ammonium nitrate explosive, wherein the rock-expanded ammonium nitrate explosive is as described in any one of claims 1-9, characterized in that, The steps are as follows: Ammonium nitrate is mixed with water to obtain an aqueous phase; then the aqueous phase, composite oil phase and expanding agent are mixed and expanded, and wood flour and porous granular ammonium nitrate are added and mixed evenly to obtain rock-expanded ammonium nitrate explosive.

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