On-site mixed emulsion explosive for underground mine upward hole and preparation method of on-site mixed emulsion explosive

Abstract

The invention discloses an on-site mixed emulsion explosive for an underground mine upward hole and a preparation method of the on-site mixed emulsion explosive. The emulsion explosive comprises nitric acid, sodium nitrate or urea, water, a compound oil phase, a sensitizer, an accelerant, modified chitosan and sodium carboxymethyl cellulose. The preparation method of the emulsion explosive comprises the following steps: S1, uniformly mixing ammonium nitrate, sodium nitrate, water and a compound oil phase, and emulsifying to obtain an emulsion matrix; s2, preparation of sensitizer liquid: S21, mixing sodium nitrite with water to obtain a first mixed solution; s22, uniformly mixing the modified chitosan with the first mixed solution to obtain a second mixed solution; s23, uniformly mixing sodium carboxymethyl cellulose with the second mixed solution to obtain a sensitizer solution; and S3, separately conveying the accelerant liquid and the sensitizer liquid, and mixing the accelerant liquid and the sensitizer liquid with the emulsion matrix to prepare the emulsion explosive. According to the invention, the problem that the produced emulsion matrix is high in viscosity and difficult to convey due to the pursuit of high viscosity of the on-site mixed emulsion explosive in the use process is solved.

Description

Technical Field

[0001] The invention relates to the technical field of emulsion explosives, in particular to on-site mixed emulsion explosives for upholes in underground mines and a preparation method thereof. Background Art

[0002] The on-site mixed emulsion explosives for upward hole charging generally refer to bulk colloidal emulsion explosives suitable for charging upward fan-shaped medium-deep blastholes in underground mines. In the process of use, in addition to meeting the requirements of explosive explosion performance, it is also necessary to ensure a low rate of explosive drop and facilitate pumping of charging. The existing on-site mixed emulsion explosives for upward hole charging often produce high latex viscosity and high production pressure due to the pursuit of high viscosity during use, which is difficult to pump and transport through pipelines, affecting production capacity and work efficiency and bringing certain safety hazards.

[0003] After retrieval, the patent that publication number is CN102276373A discloses porous granular ammonium oil-fuel oil explosive adhesive, adds thickener polyacrylamide in the production process of explosive, realizes not falling medicine in the upward hole charging process, but the method can sharply improve matrix viscosity, reduces matrix fluidity, makes matrix pumping difficulty, greatly reduces production efficiency. Secondly, thickeners such as polyacrylamide can form water-insoluble gel colloid quickly because of swelling action in the process of mixing with water, and this colloid once forms, is difficult for pumping and mixing with emulsion explosive, thus is difficult to directly pump and mix with latex matrix in the blast hole of blasting scene. In addition, when thickener and bulk matrix are mixed by pumping, due to poor miscibility of thickener and bulk matrix, plus the lubrication of a large amount of water in thickener, latex matrix can be made to be difficult to adhere to and fall off in a large number in blast hole after a period of time. The patent with publication number CN108640806A discloses a novel colloidal emulsion explosive for underground mining. A microcapsule-coated thickener is added to the emulsion explosive. During the pumping and spraying charging process, the thickening microcapsules are subjected to extrusion, friction and spraying impact, and the microcapsules outside thereof are destroyed and the thickener is exposed, so that the viscosity of the underground mining emulsion explosive is enhanced after reaching the blast hole. However, the thickening microcapsules described in the patent are difficult to prepare, which increases the production cost of the emulsion explosive, and the physical destruction process of the thickening microcapsules is uncontrollable. In addition, the technology of rapid foaming and thickening with a low-viscosity matrix will have serious sensitization aftereffects when high-concentration strong acid is rapidly sensitized in actual applications, resulting in too low matrix density, a large number of invalid bubbles, and a serious impact on the blasting effect.

[0004] Therefore, there is an urgent need to develop a new on-site mixed emulsion explosive for use in underground mines, which can meet the fluidity of the matrix during pumping while ensuring the adhesion of the emulsion explosive after pumping. Summary of the invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes an on-site mixed emulsion explosive for upward holes in underground mines and a preparation method thereof, which solves the problem that the existing on-site mixed emulsion explosives suitable for charging upward blast holes pursue high viscosity during use, the latex matrix produced has high viscosity, the production pressure is high, and it is difficult to pump and transport through pipelines, thus affecting production capacity and work efficiency.

[0006] The on-site mixed emulsion explosive for uphole in underground mines provided by the present invention comprises the following raw materials in parts by weight: 60-80 parts of ammonium nitrate, 5-10 parts of sodium nitrate or urea, 12-18 parts of water, 5-8 parts of composite oil phase, 0.5-1.8 parts of sensitizer, 0.2-0.5 parts of accelerator, 0.5-5 parts of modified chitosan and 0.05-0.6 parts of sodium carboxymethyl cellulose.

[0007] Preferably, the accelerator is one or more of acetic acid, citric acid, phosphoric acid, oxalic acid, nitric acid and magnesium nitrate.

[0008] Preferably, the sensitizer is sodium nitrite.

[0009] Preferably, the method for preparing the modified chitosan comprises the following steps: Chitosan with a deacetylation degree of 55%-95% is dissolved in a mixed solution of weak acid and alcohol, stirred at 40-80°C for 15-30 minutes, then 10wt%-30wt% acetic anhydride solution is added, stirred for 15-45 minutes, and allowed to stand for 1-5 hours. Alkaline solution is slowly added dropwise to the mixed solution until the solution is completely precipitated, and surface-modified chitosan is obtained after filtration, washing and drying.

[0010] Preferably, the weak acid is one or more of acetic acid, citric acid, phosphoric acid, oxalic acid and formic acid.

[0011] Preferably, the alcohol is one or more of methanol, ethanol and isopropanol.

[0012] Preferably, the base is sodium hydroxide and / or potassium hydroxide.

[0013] Preferably, the mass ratio of chitosan to acetic anhydride is 1:0.05-1.

[0014] The method for preparing the above-mentioned on-site mixed emulsion explosive for upward holes in underground mines proposed by the present invention comprises the following steps: S1: Evenly mix ammonium nitrate, sodium nitrate, water and composite oil phase, and prepare latex matrix after emulsification; S2: preparation of sensitizer solution, which contains the following raw materials in percentage: sodium nitrite 20-30%, water 40-57%, modified chitosan 12-32%, sodium carboxymethyl cellulose 0.5-3%; S21: mixing sodium nitrite with water to obtain a first mixed solution; S22: mixing the modified chitosan with the first mixed solution and heating to 50-90° C., and mixing evenly to obtain a second mixed solution; S23: mixing sodium carboxymethyl cellulose and the second mixed solution and heating to 70-90° C., and mixing evenly to obtain a sensitizer solution; S3: The accelerant liquid and the sensitizer liquid are transported separately and mixed with the latex matrix to prepare the on-site mixed emulsion explosive for upward holes in underground mines.

[0015] Mechanism of action In underground mining blasting, the on-site mixed emulsion explosive for upward hole charging generally refers to the on-site mixed emulsion explosive suitable for underground upward blasthole charging. In the process of use, in addition to meeting the explosive performance of the explosive, it is also necessary to ensure a low rate of drug drop and facilitate the pumping and charging requirements. The present invention disperses the compound thickener in the weakly alkaline sensitizer (sodium nitrite) and stores it in the material box of the on-site mixed explosive vehicle to reduce the viscosity of chitosan and facilitate the pumping and mixing of the sensitizer liquid. The sensitizing promoter (acidic substance) is separated from the sensitizer liquid and stored in another material box. A low-viscosity latex matrix is ​​used at the blasting site to reduce the pumping pressure. During in-hole sensitization, the sensitizer liquid containing the compound thickener and the acid promoter are mixed with the latex matrix at the same time. The viscosity of chitosan increases after encountering acid, and the matrix is ​​rapidly thickened during the in-hole sensitization process. Sodium carboxymethyl cellulose containing alcoholic hydroxyl groups can delay the degradation of chitosan, improve the acid resistance of the prepared viscous explosive, and thus enhance the stability of the explosive. At the same time, the viscosity of sodium carboxymethyl cellulose increases after cooling in the hole, which promotes the further improvement of the viscosity of the explosive after cooling in the hole, and is more firmly attached to the hole wall, effectively solving the serious problem of charge return to the hole in underground mines. For low-temperature use environments, the low-temperature resistance of viscous explosives can be enhanced by increasing the ratio of sodium carboxymethyl cellulose to chitosan. Therefore, the viscous explosives prepared by this method can also maintain good performance in a low-temperature and acidic environment, and can remain stable within the range of pH 2-10, meeting the use conditions of emulsion explosives. The present invention uses a low-viscosity matrix during the pumping process, and the explosives in the blasthole play the function of a thickener after encountering an acidic accelerator, thereby solving the contradiction between the fluidity and viscosity of traditional on-site mixed emulsion explosives.

[0016] Beneficial technical effects (1) The on-site mixed emulsion explosive for upward hole charging of the present invention isolates the thickener from the latex matrix, thereby reducing the viscosity of the matrix during pumping, alleviating the pumping pressure and increasing the output.

[0017] (2) The present invention dissolves chitosan in a weakly alkaline sodium nitrite solution after surface modification, disperses the modified chitosan in a weakly alkaline sensitizer, reduces the viscosity of chitosan, and facilitates the pumping and mixing of the sensitizer liquid containing a thickener and the matrix. At the same time, the water content of the explosive is not increased, and the detonation performance of the explosive is not affected.

[0018] (3) The present invention avoids the step of adding an additional viscosity agent at the operation site during the mixing process, making the operation easier, saving energy and improving efficiency. At the same time, it simplifies the design of the on-site mixing emulsion explosive vehicle, and is particularly suitable for the on-site mixing operation in underground mines.

[0019] (4) The present invention improves the sensitizer formula and adds a certain amount of sodium carboxymethyl cellulose to delay the degradation of chitosan, thereby improving the acid resistance of the prepared sticky explosive and further enhancing the stability of the explosive. It is found that the viscosity of the prepared sticky explosive does not decrease when stored at room temperature for more than 30 days.

[0020] (5) In the process of in-pore sensitization of the present invention, chitosan contacts with an acidic accelerator, and the viscosity increases, thereby achieving in-pore thickening of the emulsion explosive, thereby resolving the contradiction between the fluidity and adhesion of conventional emulsion explosives.

[0021] (6) The viscosity of the sodium carboxymethyl cellulose of the present invention increases after the temperature in the hole decreases, which promotes further increase in the viscosity of the explosive after cooling in the hole, making it more firmly attached to the hole wall, and effectively solving the serious problem of explosive return in the hole in underground mines.

[0022] (7) For low-temperature use environments, the low-temperature resistance of sticky explosives can be enhanced by increasing the ratio of sodium carboxymethyl cellulose to chitosan. The sticky explosives prepared by this method can maintain good performance even in low-temperature and acidic environments, and can remain stable within the pH range of 2-10, meeting the use conditions of emulsion explosives. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of the preparation process of on-site mixed emulsion explosives. DETAILED DESCRIPTION

[0024] The present invention will be further explained below in conjunction with specific embodiments.

[0025] The composite oil phase in the embodiment of the present invention was purchased from Shanxi Jiulian Hongyuan Chemical Co., Ltd.; chitosan was commercially available.

[0026] Example 1 The on-site mixed emulsion explosive for upward holes in underground mines provided by the present invention comprises the following raw materials by weight: 65 kg of ammonium nitrate, 8 kg of sodium nitrate, 16.5 kg of water, 6 kg of composite oil phase, 0.8 kg of sensitizer, 0.4 kg of acetic acid, 3 kg of modified chitosan and 0.3 kg of sodium carboxymethyl cellulose.

[0027] The method for preparing the on-site mixed emulsion explosive for upward holes in underground mines proposed by the present invention comprises the following steps: S1: Evenly mix ammonium nitrate, sodium nitrate, water and composite oil phase, and prepare latex matrix after emulsification; S2: Sodium nitrite is mixed with water to obtain a first mixed solution, modified chitosan is mixed with the first mixed solution and heated to 70° C., and mixed evenly to obtain a second mixed solution; sodium carboxymethyl cellulose is mixed with the second mixed solution and heated to 80° C., and mixed evenly to obtain a sensitizer solution; S3: Mixing the latex matrix, the accelerator and the sensitizer liquid to prepare the on-site mixed emulsion explosive for the uphole in the underground mine, wherein the accelerator and the sensitizer liquid are transported separately.

[0028] Example 2 The on-site mixed emulsion explosive for upward holes in underground mines provided by the present invention comprises the following raw materials by weight: 60 kg of ammonium nitrate, 8 kg of sodium nitrate, 18 kg of water, 5 kg of mixed oil phase, 0.4 kg of sodium nitrite, 0.2 kg of citric acid, 0.5 kg of modified chitosan and 0.05 kg of sodium carboxymethyl cellulose.

[0029] The preparation method of the on-site mixed emulsion explosive for upward holes in underground mines in this embodiment is the same as that in Example 1.

[0030] Example 3 The on-site mixed emulsion explosive for upward holes in underground mines provided by the present invention comprises the following raw materials by weight: 80 kg of ammonium nitrate, 10 kg of sodium nitrate, 18 kg of water, 8 kg of mixed oil phase, 0.9 kg of sodium nitrite, 0.5 kg of oxalic acid, 5 kg of modified chitosan, and 0.6 kg of sodium carboxymethyl cellulose.

[0031] The preparation method of the on-site mixed emulsion explosive for upward holes in underground mines in this embodiment is the same as that in Example 1.

[0032] Comparative Example 1 The on-site mixed emulsion explosive for upward holes in underground mines proposed in this scheme contains the following raw materials by weight: 65 kg of ammonium nitrate, 8 kg of sodium nitrate, 16.5 kg of water, 6 kg of composite oil phase, 0.8 kg of sensitizer, 0.4 kg of acetic acid, and 3 kg of modified chitosan.

[0033] The preparation method of the on-site mixed emulsion explosive for upward holes in underground mines in this embodiment is the same as that in Example 1.

[0034] Application Examples Taking Example 1 as an example, the on-site preparation and hole filling process of the emulsion explosive for the downhole in the underground mine proposed by the present invention is as follows: Add the latex matrix and the prepared accelerator into the matrix box and accelerator box of the on-site emulsion explosive mixing vehicle, respectively, and add the modified chitosan and sensitizer into the sensitizer box. The mixing vehicle drives to the blasting operation surface, and the lifting arm device lifts the pipe delivery device, drug delivery pipe and nozzle to the vicinity of the blast hole. The nozzle is aimed at the blast hole, the pipe delivery device is started, and the drug delivery pipe is pushed to the bottom of the blast hole. The charge amount is set according to the depth of the blast hole. The on-site pharmaceutical process is as follows Figure 1 As shown, start the charging procedure, open the latex valve, accelerator valve, and sensitizer valve, and start the latex pump (screw pump), accelerator pump, and sensitizer pump. The latex matrix, accelerator, and sensitizer are quantitatively delivered according to the system setting ratio, the latex pump flow is automatically counted according to the latex matrix mass flowmeter, and the sensitizer and accelerator are measured by the flowmeter. The latex matrix is ​​a low-viscosity matrix, which ensures that the latex matrix is ​​smoothly transported in the drug delivery tube. The latex matrix, accelerator, and sensitizer containing thickener are fully mixed through the static mixer at the end. After the mixed fluid is pushed into the blasthole, the sensitizer and accelerator, and the thickener and accelerator react fully, and after uniform sensitization and thickening, a mixed emulsion explosive for the underground mine upward hole is formed. During the charging process, the tube feeder and the reel will automatically retract the tube according to the set charging speed, and the charging amount will be automatically measured, and the machine will automatically stop when the set value is reached. After the blasthole charging is completed, the charging tube is recovered for the cycle loading of the next blasthole. The test results show that the emulsion explosive mixed on-site in the underground mine can be pumped smoothly under a pressure of 1MPa. After the charge is sprayed through the pumping hose, it can quickly achieve final setting within 10-20 seconds. After 3 hours of charging in a 20-meter hole, the return rate is less than 6%. After sampling and storage for 30 days, the emulsion explosive is still sticky.

[0035] The viscosity of the viscous explosive obtained in Comparative Example 1 decreased significantly after being placed at room temperature for 24 hours due to the acid-promoted degradation of chitosan, and the viscous explosive no longer met the requirements for use in upward holes.

[0036] According to the national standard method, the high and low temperature detonation test, detonation velocity, intensity and appearance judgment were carried out on the on-site mixed emulsion explosives prepared in the above Examples 1-3 and Comparative Example 1. The test results are shown in Table 1.

[0037] Table 1 Performance parameters of field mixed emulsion explosives for upward holes in underground wells It can be seen that the underground upward hole mixed emulsion explosive in the embodiment has excellent detonation performance and meets the storage stability requirements.

[0038] The present invention has been described in detail above in conjunction with the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the field without departing from the purpose of the present invention.

Claims

1. On-site mixed emulsion explosive for use in underground mines, characterized in that: The invention comprises the following raw materials in parts by weight: 60-80 parts of ammonium nitrate, 5-10 parts of sodium nitrate or urea, 12-18 parts of water, 5-8 parts of composite oil phase, 0.5-1.8 parts of sensitizer, 0.2-0.5 parts of accelerator, 0.5-5 parts of modified chitosan and 0.05-0.6 parts of sodium carboxymethyl cellulose.

2. The on-site mixed emulsion explosive for uphole use in underground mines according to claim 1, characterized in that: The accelerator is one or more of acetic acid, citric acid, phosphoric acid, oxalic acid, nitric acid and magnesium nitrate.

3. The on-site mixed emulsion explosive for uphole use in underground mines according to claim 1, characterized in that: The sensitizer is sodium nitrite.

4. The on-site mixed emulsion explosive for uphole use in underground mines according to claim 1, characterized in that: The method steps for preparing the modified chitosan are as follows: Chitosan with a deacetylation degree of 55%-95% is dissolved in a mixed solution of weak acid and alcohol, stirred at 40-80°C for 15-30 minutes, then 10wt%-30wt% acetic anhydride solution is added, stirred for 15-45 minutes, and allowed to stand for 1-5 hours. Alkaline solution is slowly added dropwise to the mixed solution until the solution is completely precipitated, and surface-modified chitosan is obtained after filtration, washing and drying.

5. The on-site mixed emulsion explosive for uphole use in underground mines according to claim 4, characterized in that: The weak acid is one or more of acetic acid, citric acid, phosphoric acid, oxalic acid and formic acid.

6. The on-site mixed emulsion explosive for uphole use in underground mines according to claim 4, characterized in that: The alcohol is one or more of methanol, ethanol and isopropanol.

7. The on-site mixed emulsion explosive for uphole use in underground mines according to claim 4, characterized in that: The alkali is sodium hydroxide and / or potassium hydroxide.

8. The on-site mixed emulsion explosive for uphole use in underground mines according to claim 4, characterized in that: The mass ratio of chitosan to acetic anhydride is 1:0.05-1.

9. The method for preparing the on-site mixed emulsion explosive for uphole use in underground mines according to any one of claims 1 to 8, characterized in that: The steps are as follows: S1: Evenly mix ammonium nitrate, sodium nitrate, water and composite oil phase, and prepare latex matrix after emulsification; S2: Preparation of sensitizer solution S21: mixing sodium nitrite with water to obtain a first mixed solution; S22: mixing the modified chitosan with the first mixed solution and heating to 50-90° C., and mixing evenly to obtain a second mixed solution; S23: mixing sodium carboxymethyl cellulose and the second mixed solution and heating to 70-90° C., and mixing evenly to obtain a sensitizer solution; S3: The accelerant liquid and the sensitizer liquid are transported separately and mixed with the latex matrix to prepare the on-site mixed emulsion explosive for upward holes in underground mines.

10. The method for preparing on-site mixed emulsion explosive for uphole drilling in underground mines according to claim 9, characterized in that: The sensitizer solution contains the following raw materials in percentage: 20-30% sodium nitrite, 40-57% water, 12-32% modified chitosan and 0.5-3% sodium carboxymethyl cellulose.

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