A white clay-based ANFO inert filler, its preparation method and application

Abstract

The invention provides a white mud-based ANFO inert filler, a preparation method thereof and an application. Calculated by weight parts, the raw materials for preparing the white mud-based ANFO inert filler include: 82-90 parts of white mud, 0.5-2.5 parts of pore-forming agent, and 3-15 parts of expanding agent; wherein, calculated by weight percentage, the white mud contains 10-15% of C, 55-75% of SiO2, the expanding agent includes Fe2O3, and the pore-forming agent includes SiC. The invention can solve the problem in the prior art that there is a lack of an inert filler that can reduce the density of ANFO, stabilize the detonation velocity, and not affect its sensitization degree and stability.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste resource utilization and industrial explosives, and in particular to a white mud-based ammonium nitrate oil explosive inert filler, a preparation method and application thereof. Background Art

[0002] High-step pre-splitting blasting is a commonly used technical means for controlled blasting of open-pit coal mine slopes. After the main blasting hole of the open-pit mine is blasted, a relatively complete smooth slope can be formed along the pre-splitting surface. At present, in order to ensure the pre-splitting effect, the measures taken are to load low-density ammonium oil explosives into the pre-splitting holes, while reducing the density and detonation velocity of the explosives, increasing the charge amount, so that the energy of the explosives acts evenly on the rock wall, and reducing the degree of damage to the surrounding rock medium when the explosives explode. The current method to reduce the density and detonation velocity of ammonium oil explosives is to add inert low-density materials to the explosives. This material does not participate in the reaction of the explosive components and does not affect the stability of the explosive components and the storage performance of the explosives.

[0003] The inert material used in the low-density ammonium nitrate oil explosive currently used in engineering blasting is expanded perlite, but due to its high oil absorption rate of about 130%, most of the diesel is absorbed by the expanded perlite, which reduces the sensitization of the explosive and affects the reaction between diesel and ammonium nitrate, resulting in frequent failure to detonate in actual applications, which not only wastes explosives but also reduces coal mining efficiency.

[0004] In view of this, it is necessary to provide an inert filling material for explosives with low oil absorption, which can reduce the density and stabilize the detonation velocity while not reducing the sensitization of the explosives and improving the stability of the explosives. Summary of the invention

[0005] The main purpose of the invention is to provide a white mud-based ammonium nitrate oil-fuel mixture inert filler, a preparation method and an application thereof, so as to solve the problem in the prior art that there is a lack of inert fillers that can reduce the density of ammonium nitrate oil-fuel mixture, stabilize the detonation velocity, and do not affect the sensitization and stability thereof.

[0006] In order to achieve the above-mentioned object, according to one aspect of the present invention, a white mud-based ammonium nitrate-fuel oil explosive inert filler is provided, wherein the raw materials for preparation thereof include, by weight: 82-90 parts of white mud, 0.5-2.5 parts of pore-forming agent, and 3-15 parts of expander; wherein, by weight percentage, the white mud contains C10-15%, SiO2 55-75%, the expander includes Fe2O3, and the pore-forming agent includes SiC.

[0007] Furthermore, in parts by weight, the raw materials for preparation include: 84-88 parts of white mud, 1.0-2.0 parts of pore-forming agent, and 3-10 parts of expansion agent.

[0008] Furthermore, the raw materials for preparation further include glass powder; preferably, the particle size of the glass powder is ≤ 200 mesh.

[0009] Furthermore, the particle size of the inert filler of the white mud-based ANFO is 0.5 - 2.5 mm.

[0010] Furthermore, the particle size of the pore-forming agent is ≤ 200 mesh; preferably, the expanding agent further includes alkali metal carbonates; preferably, the particle size of the expanding agent is ≤ 200 mesh.

[0011] To achieve the above object, according to one aspect of the present invention, there is provided a method for preparing the above-mentioned inert filler of the white mud-based ANFO, which includes: mixing white mud, a pore-forming agent, and an expanding agent and then granulating to obtain green pellets; and then performing calcination to obtain the inert filler of the white mud-based ANFO.

[0012] Furthermore, after obtaining the green pellets, the surface of the green pellets is coated with glass powder, and then calcination is performed to obtain the inert filler of the white mud-based ANFO; preferably, by weight, the water content of the green pellets is 31 - 35%.

[0013] Furthermore, the calcination includes a first calcination and a second calcination performed in sequence; preferably, the temperature of the first calcination is 450 - 500 °C and the time is 20 - 30 min; preferably, the temperature of the second calcination is 1100 - 1200 °C and the time is 20 - 30 min.

[0014] According to another aspect of the present invention, there is provided an application of the above-mentioned inert filler of the white mud-based ANFO in ANFO.

[0015] Applying the technical solution of the present invention, there is provided an inert filler that can reduce the density of ANFO, stabilize the detonation velocity, and improve the stability of the explosive. Due to the low oil absorption rate of the inert filler of the present invention, the diesel in the explosive is mainly adsorbed on the surface of porous granular ammonium nitrate, and still undergoes an oxidation-reduction reaction with ammonium nitrate during detonation. Therefore, it will not significantly reduce the sensitization degree of the explosive to cause misfire. Specific Embodiments

[0016] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0017] To solve the problems in the prior art as described above, according to one aspect of the present invention, a white mud-based ANFO inert filler is provided. Calculated by weight parts, the raw materials for its preparation include: 82-90 parts of white mud, 0.5-2.5 parts of pore-forming agent, and 3-15 parts of swelling agent; wherein, calculated by weight percentage, the white mud contains 10-15% of C and 55-75% of SiO2, the swelling agent includes Fe2O3, and the pore-forming agent includes SiC.

[0018] The inert filler according to the present invention uses white mud as the basic component. The carbon content in the white mud is about 10-15 wt%. These carbons can reduce Fe2O3 in the swelling agent to generate CO and / or CO2 gas and FeO. FeO has a strong fluxing effect, which can melt SiO2 in the white mud to produce oxygen ions; the oxygen ions further react with SiC at high temperature to generate CO and / or CO2 gas; the white mud used in the present invention has a high silicon content and can generate a liquid phase with appropriate viscosity in the presence of high temperature and Fe2O3, enclosing the gas substances generated in the high-temperature reaction inside the melt, and finally enabling the gas to form an independent pore structure inside.

[0019] The alumina contained in the white mud can also provide a certain strength for the filler.

[0020] Due to the characteristics of the white mud component, spontaneous combustion will occur during the high-temperature reaction process, so sufficient internal heat can be provided, which can reduce the calcination energy consumption and at the same time realize the recovery of surplus heat.

[0021] Through the synergistic effect of each component, the inert filler of the present invention has an appropriate loose bulk density (0.4-0.65 g / cm 3 ), a lower oil absorption rate (<5%, by weight), and a higher strength (>5 N), which very well matches the usage requirements of existing industrial explosives and has broad application prospects. In addition, the white mud in the inert filler of the present invention belongs to solid waste, has a wide source and low cost, which is not only beneficial to the resource utilization of solid waste but also convenient for industrial production.

[0022] Specifically, the weight percentage of white mud is 82-90%. When it is higher than this weight part, it is difficult to form more internal pores and a stable skeleton structure; on the contrary, if it is lower than this weight part, it is difficult to exert the beneficial effects of white mud.

[0023] The addition amount of the pore-forming agent should not be too much. When it is higher than this ratio, a large amount of SiO2 protective film will be generated on the surface, which prevents the diffusion of gas and instead cannot generate a large number of air holes; when it is lower than this ratio, a large amount of gas cannot be generated, and enough pore-like structures cannot be formed, and the prepared filler has a large density and cannot fully achieve the effect of low explosive density.

[0024] The weight parts of the swelling agent are 3 to 15 parts. With such a weight percentage of the swelling agent, it can not only fully react with the unburned carbon in the white mud to generate sufficient gas, but also the formed product FeO has a strong fluxing effect to promote the melting of SiO2 in the white mud, enabling the reaction system to form a liquid phase with an appropriate viscosity and promoting the formation of an independent pore structure in the system. When higher than this ratio, the fluxing effect is too strong, and too much liquid phase is formed in the system, causing the generated gas to escape from the system, which instead increases the density of the filler; when lower than this ratio, the swelling effect is not achieved, and less liquid phase is formed in the system, also increasing the density of the filler.

[0025] In a preferred embodiment, in order to better achieve the reduction of density and the stabilization of detonation velocity without affecting the sensitization, based on weight parts, the preparation raw materials include: 84 to 88 parts of white mud, 1.0 to 2.0 parts of pore-forming agent, and 3 to 10 parts of swelling agent.

[0026] In a preferred embodiment, the preparation raw materials include: 88 parts of white mud, 2 parts of pore-forming agent, and 10 parts of swelling agent. Through experimental exploration, this preferred ratio can provide more excellent properties, including a more suitable bulk density, strength, and oil absorption rate.

[0027] For the purpose of reducing the oil absorption rate of the inert filler and increasing its strength, in a preferred embodiment, the preparation raw materials further include glass powder; preferably, the particle size of the glass powder is below 200 mesh. In some embodiments of the present invention, the ratio of the amount of glass powder to the total weight of white mud, pore-forming agent, and swelling agent is 100:(7 - 13). In actual operation, after mixing white mud, pore-forming agent, and swelling agent to granulate to obtain green pellets, the amount of glass powder should be such that a uniform coating can be formed on the surface of the green pellets.

[0028] The particle size of the glass powder is preferably within the above range, which is more conducive to mixing evenly with other raw materials and more fully realizing its function. At high temperatures, the glass powder will melt and seal the pores formed by the filler, which is beneficial to reducing the oil absorption rate.

[0029] In a preferred embodiment, the particle size of the inert filler of white mud-based ANFO is 0.5 to 2.5 mm. Such a preferred particle size is more conducive to mixing the filler with porous granular ammonium nitrate to prepare a uniform explosive. If the particle size is higher than this range, the filler is more likely to concentrate on the upper layer of the explosive; conversely, if the particle size is lower than this range, the filler is prone to agglomeration, resulting in a non-uniform explosive with unstable performance. In actual applications, preferably, the average value of the particle size is 1.0 to 2.0 mm.

[0030] In a preferred embodiment, the particle size of the pore former is below 200 mesh. The particle size of the above-mentioned preferred pore former is conducive to mass transfer reaction and forms stable and uniform pores. If the particle size is higher than this range, the contact surface between reactants is reduced, the mass transfer reaction is too slow, and it is difficult to form a relatively stable pore structure.

[0031] In a preferred embodiment, the expanding agent further includes alkali metal carbonates; preferably, the particle size of the expanding agent is below 200 mesh. The particle size of the preferred expanding agent within the above range is more conducive to the reaction.

[0032] According to another aspect of the present invention, there is also provided a method for preparing the above-mentioned inert filler for white mud-based ammonium nitrate fuel oil explosive, which includes: mixing white mud, pore former, and expanding agent and then granulating to obtain green pellets; secondly, performing roasting to obtain the inert filler for white mud-based ammonium nitrate fuel oil explosive.

[0033] During the roasting process, the unburned carbon in the white mud reacts with the expanding agent, part of the SiO2 forms a liquid phase, dissolves to generate oxygen ions and reacts with the pore former, part of the SiO2 is transformed from an amorphous state to a lower-density cristobalite phase, and part of the SiO2 forms a stable aluminosilicate structure with alumina, improving the strength of the filler.

[0034] In a typical embodiment of the present invention, after roasting, preferably, it is naturally cooled to room temperature (15 - 35 °C). When using a rapid cooling method, it may cause the pellets to explode, reducing the strength of the filler.

[0035] In a preferred embodiment, the surface of the green pellets is coated with glass powder and then roasted to obtain the inert filler for white mud-based ammonium nitrate fuel oil explosive; preferably, by weight, the water content of the green pellets is 31 - 35%. In a typical embodiment of the present invention, the green pellets are placed in an excess of glass powder, so that the glass powder forms a coating layer on the surface of the green pellets, then the excess glass powder is sieved off, and then roasting is performed. The glass powder plays a role in sealing pores and increasing strength. The above-mentioned preferred conditions are more conducive to the formation of a uniform and tight coating layer of glass powder on the surface of the green pellets.

[0036] In practical applications, preferably, granulation is performed using a granulator, and then screening is carried out to obtain green pellets with a target particle size range.

[0037] For the purpose of more complete roasting, in a preferred embodiment, the roasting includes a first roasting and a second roasting carried out in sequence; preferably, the temperature of the first roasting is 450 - 500 °C and the time is 20 - 30 min; preferably, the temperature of the second roasting is 1100 - 1200 °C and the time is 20 - 30 min. In such a preferred roasting treatment, the first roasting is also called pre-roasting, the purpose of which is to reduce the cracking of the material balls caused by the sharp temperature change after entering the high temperature, and at the same time gradually generate gas in the material balls; the purpose of the second roasting is to make the substances in the material balls react, and at the same time form a liquid phase on the surface to seal the gas in the pores.

[0038] In a preferred embodiment, in the stage of rising from room temperature to the first roasting temperature and the stage of rising from the first roasting temperature to the second roasting temperature, the heating rate is independently 5 - 10 °C / min for each. Such a heating rate is more conducive to complete roasting.

[0039] According to another aspect of the present invention, there is provided an application of the above-mentioned white mud-based ANFO inert filler in ANFO.

[0040] The following further describes the present application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.

[0041] In the following embodiments, the white mud is derived from the high-silicon tail slag produced by the "one-step acid leaching method for extracting alumina" from fly ash, in which the weight content of C is 12% and the weight content of SiO2 is 55%.

[0042] Example 1

[0043] Weigh and mix white mud, SiC powder (280 mesh), and Fe2O3 (200 mesh) in a weight ratio of 90.5:2.5:7, then place the mixture in a high-speed granulator for granulation, and then screen to obtain raw material balls with a size of 0.5 - 2.5 mm. Coat a layer of glass powder (particle size 250 mesh) on the surface of the raw material balls, and the weight ratio of the glass powder to the raw material balls is 100:9. Then pre-roast at 450 °C for 30 min, and finally roast at 1100 °C for 20 min with a heating rate of 5 °C / min. After natural cooling, a white mud-based inert filler is obtained, with a loose bulk density of 0.55 g / cm 3 , a strength of 15.2 N, and an oil absorption rate of 3.5 wt%.

[0044] Apply the white mud-based inert filler to ANFO, and use a 110 PVC pipe for charging. The composition of ANFO is: porous granular ammonium nitrate 89 wt%, diesel 6 wt%, and white mud-based inert filler 5 wt%; its detonation velocity is 2220 m / s.

[0045] Example 2

[0046] It is different from Example 1 in that white mud, SiC powder (particle size 280 mesh), and Fe2O3 (200 mesh) are weighed and mixed evenly according to a weight ratio of 87.5:2.5:10.

[0047] A white mud-based inert filler is obtained, and its loose bulk density is 0.44 g / cm 3 , the strength is 13.7 N, and the oil absorption rate is 3.8 wt%.

[0048] The white mud-based inert filler is applied to ammonium nitrate fuel oil explosive, and the composition of the ammonium nitrate fuel oil explosive is the same as that in Example 1; its detonation velocity is 1934 m / s.

[0049] Example 3:

[0050] It is different from Example 1 in that white mud, SiC powder (particle size 280 mesh), and Fe2O3 (200 mesh) are weighed and mixed evenly according to a weight ratio of 82.5:2.5:15.

[0051] A white mud-based inert filler is obtained, and its loose bulk density is 0.48 g / cm 3 , the strength is 9.8 N, and the oil absorption rate is 4.7 wt%.

[0052] The white mud-based inert filler is applied to ammonium nitrate fuel oil explosive, and the composition of the ammonium nitrate fuel oil explosive is the same as that in Example 1; its detonation velocity is 2041 m / s.

[0053] Example 4:

[0054] It is different from Example 1 in that white mud, SiC powder (particle size 280 mesh), and Fe2O3 (200 mesh) are weighed and mixed evenly according to a weight ratio of 84.5:0.5:15.

[0055] A white mud-based inert filler is obtained, and its loose bulk density is 0.56 g / cm 3 , the strength is 15.2 N, and the oil absorption rate is 3.5 wt%.

[0056] The white mud-based inert filler is applied to ammonium nitrate fuel oil explosive, and the composition of the ammonium nitrate fuel oil explosive is the same as that in Example 1; its detonation velocity is 2306 m / s.

[0057] Example 5

[0058] It is different from Example 1 in that white mud, SiC powder (particle size 280 mesh), and Fe2O3 (200 mesh) are weighed and mixed evenly according to a weight ratio of 88:2:10.

[0059] A white mud-based inert filler is obtained, and its loose bulk density is 0.4 g / cm 3 , the strength is 13.2 N, and the oil absorption rate is 3.8 wt%.

[0060] The white mud-based inert filler is applied to ANFO, and the composition of ANFO is the same as that in Example 1; its detonation velocity is 1892 m / s.

[0061] Example 6

[0062] The difference from Example 5 is that the particle size of the green pellets is 3 - 5 mm.

[0063] The white mud-based inert filler is obtained, with a loose bulk density of 0.35 g / cm 3 , a strength of 13.9 N, and an oil absorption rate of 3.5 wt%.

[0064] The white mud-based inert filler is applied to ANFO, and the composition of ANFO is the same as that in Example 1; its detonation velocity is tested three times, which are 1560 m / s, 1934 m / s, and 1700 m / s respectively, and the average detonation velocity is 1731 m / s.

[0065] Example 7

[0066] The difference from Example 1 is that after making the green balls, they are directly calcined without being coated with glass powder.

[0067] The white mud-based inert filler is obtained, with a loose bulk density of 0.52 g / cm 3 , a strength of 4.8 N, and an oil absorption rate of 23.5 wt%. The white mud-based inert filler is applied to ANFO, and the composition of ANFO is the same as that in Example 1; its detonation velocity is 1902 m / s.

[0068] Example 8

[0069] The difference from Example 5 is that the particle size of SiC powder is 150 mesh and the particle size of Fe2O3 powder is 150 mesh.

[0070] The white mud-based inert filler is obtained, with a loose bulk density of 0.62 g / cm 3 , a strength of 14.4 N, and an oil absorption rate of 3.2 wt%. The white mud-based inert filler is applied to ANFO, and the composition of ANFO is the same as that in Example 1; its detonation velocity is 2521 m / s.

[0071] Example 9

[0072] The difference from Example 5 is that the temperature of the first calcination is 300 °C and the time is 15 min, and the temperature of the second calcination is 900 °C and the time is 15 min.

[0073] The white mud-based inert filler is obtained, with a loose bulk density of 0.85 g / cm 3 , a strength of 4.5 N, and an oil absorption rate of 24.4 wt%.

[0074] The white clay-based inert filler is applied to ammonium nitrate fuel oil explosive, and the composition of the ammonium nitrate fuel oil explosive is the same as that in Example 1; its detonation velocity is 2772 m / s.

[0075] Comparative Example 1

[0076] The purchased expanded perlite has a loose bulk density of 0.13 g / cm 3 , a strength of 1.2 N, and an oil absorption rate of 132 wt%.

[0077] It is applied to ammonium nitrate fuel oil explosive, and the composition of the ammonium nitrate fuel oil explosive is the same as that in Example 1, and the explosive fails to detonate. Its addition amount is reduced to 0.6%, and three detonation velocity tests are carried out, which are 1620 m / s, 2112 m / s, and 1918 m / s respectively, with an average of 1883 m / s.

[0078] It can be found through actual experiments that in Comparative Example 1, even if the explosion can occur after significantly reducing the addition amount of expanded perlite, the detonation velocity is unstable, and misfires often occur in actual applications. This not only wastes explosives but also reduces the coal mining efficiency and increases the open-pit coal mine mining cost.

[0079] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0080] The present invention prepares an inert filler for ammonium nitrate fuel oil explosive with a low oil absorption rate, which not only reduces the density and stabilizes the detonation velocity but also is beneficial to improving the stability of the explosive.

[0081] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, 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 white mud-based ANFO inert filler, characterized in that, On a weight parts basis, the preparation raw materials include: 82-90 parts of white mud, 0.5-2.5 parts of pore former, and 3-15 parts of expanding agent; wherein, by weight percentage, the white mud contains 10-15% of C, 55-75% of SiO₂, the expanding agent includes Fe₂O₃, and the pore former includes SiC; the preparation raw materials further include glass powder, and the dosage thereof is in a ratio of 100:(7-13) to the total weight of the white mud, the pore former, and the expanding agent. The loose bulk density of the inert filler of the white mud-based ANFO is 0.4 - 0.65 g / cm 3 , by weight, the oil absorption rate is < 5%, and the strength is > 5 N.

2. The inert filler of the white mud-based ANFO according to claim 1, characterized in that, On a weight parts basis, the preparation raw materials include: 84-88 parts of the white mud, 1.0-2.0 parts of the pore former, and 3-10 parts of the expanding agent.

3. The inert filler of the white mud-based ANFO according to claim 2, characterized in that, On a weight parts basis, the preparation raw materials include: 88 parts of the white mud, 2 parts of the pore former, and 10 parts of the expanding agent.

4. The inert filler for ammonium nitrate fuel oil explosive based on white mud according to any one of claims 1 to 3, characterized in that, The particle size of the glass powder ≤ 200 mesh.

5. The inert filler of the white mud-based ANFO according to any one of claims 1 to 3, characterized in that The particle size of the inert filler of the white mud-based ammonium nitrate fuel oil explosive is 0.5-2.5 mm.

6. The inert filler of the white mud-based ANFO according to any one of claims 1 to 3, characterized in that The particle size of the pore former ≤ 200 mesh.

7. The inert filler of the white mud-based ammonium nitrate fuel oil explosive according to claim 6, characterized in that The expanding agent further includes alkali metal carbonates.

8. The inert filler of the white mud-based ANFO according to claim 6, characterized in that The particle size of the expanding agent ≤ 200 mesh.

9. A preparation method of an inert filler for white mud-based ammonium nitrate fuel oil explosive according to any one of claims 1 to 8, characterized in that, Including: Mix the white mud, pore former, and expanding agent and then granulate to obtain green pellets. Secondly, conduct roasting to obtain the inert filler of the white mud-based ammonium nitrate fuel oil explosive.

10. The preparation method of the inert filler for ammonium oil explosive based on white mud according to claim 9, characterized in that, After obtaining the green pellets, coat the surface of the green pellets with glass powder, and then conduct the roasting to obtain the inert filler of the white mud-based ammonium nitrate fuel oil explosive.

11. The preparation method of the inert filler of the white mud-based ammonium explosive according to claim 10, characterized in that, By weight, the water content of the green pellets is 31-35%.

12. The preparation method of the inert filler of white mud-based ammonium nitrate fuel oil explosive according to claim 9, characterized in that, The roasting includes a first roasting and a second roasting carried out in sequence.

13. The preparation method of the inert filler of white mud-based ammonium nitrate fuel oil explosive according to claim 12, characterized in that, The temperature of the first roasting is 450-500 °C, and the time is 20-30 min.

14. The preparation method of the inert filler of the white mud-based ANFO according to claim 12, characterized in that, The temperature of the second roasting is 1100-1200 °C, and the time is 20-30 min.

15. Application of the inert filler of the white mud-based ammonium nitrate fuel oil explosive according to any one of claims 1 to 8 in ammonium nitrate fuel oil explosive.