Preparation method of on-site mixed water-gel explosive

Abstract

The invention discloses a preparation method of an on-site mixed water-gel explosive, which comprises the following steps: preparing an aqueous phase solution from ammonium nitrate, calcium nitrate and an additive, adding a liquid fuel, a gelling agent and an auxiliary combustible agent into the aqueous phase solution to prepare a thickening mother solution, adding porous granular ammonium nitrate and the auxiliary combustible agent into the thickening mother solution, and uniformly stirring to prepare the on-site mixed water-gel explosive. According to the preparation method, the blank of preparation methods of low-density and low-detonation-velocity field mixed loading explosive varieties lacking is filled, meanwhile, high-energy materials with safety risks are not used, the production process is completed through self-heating of liquid ammonium nitrate, energy consumption is reduced, and the method is suitable for industrial production. In the whole production process, the stability of each intermediate product is good, and the transportation safety is relatively high.

Description

Technical Field

[0001] The invention relates to the technical field of manufacturing civilian explosives, and in particular to a method for preparing on-site mixed water gel explosives. Background Art

[0002] The main types of explosives mixed on site in my country are ammonium oil and emulsion. However, the ammonium oil explosives mixed on site are not water resistant and have a single density. At the same time, the density adjustment range of the emulsion explosives mixed on site is small, which is suitable for blasting rocks with medium hardness or above. However, large open-pit coal mines are mainly soft rocks, and there is a lack of low-density and low-detonation-velocity mixed explosives that match them.

[0003] At present, water gel explosives have a unique gel structure system, good integrity of the explosives and good water resistance. Maxim Company abroad has a large scale of on-site mixed water gel explosives application, while domestic water gel explosives are all packaged explosives. In view of this, the inventor has introduced a method for preparing water gel explosives for on-site mixing to fill the gap. Summary of the invention

[0004] Aiming at the problem that there is a lack of on-site mixed water gel explosives in China, the invention provides a preparation method of on-site mixed water gel explosives to fill the gap of the preparation method of low-density and low-detonation-velocity on-site mixed explosives.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A method for preparing on-site mixed water gel explosive, the method comprising the following steps:

[0007] S1: adding ammonium nitrate, calcium nitrate and additives into water, heating and stirring, and preparing an aqueous solution after they are completely dissolved;

[0008] S2: adding liquid fuel, gelling agent and auxiliary combustible agent into the aqueous phase solution and stirring to form a viscous colloid to obtain a thickened mother solution;

[0009] S3: adding porous granular ammonium nitrate and auxiliary combustible agent into the thickened mother liquor and stirring, so that the porous granular ammonium nitrate and auxiliary combustible agent are evenly dispersed in the thickened mother liquor to obtain a semi-finished product;

[0010] S4: adding a sensitizer and a cross-linking agent to the semi-finished product, and mixing them evenly to form an on-site mixed water gel explosive.

[0011] The additive is urea, which reduces the crystallization point of ammonium nitrate. The cross-linking agent is a mixed solution of sodium dichromate and phosphoric acid. During the preparation process of the water-gel explosive, no high-energy materials are contained. The obtained thickened mother liquor or semi-finished product can be transported by ton barrels or tank trucks and then sent to mixing trucks. At the same time, the obtained water-gel explosive has good water resistance, a large density adjustment range, and a high degree of matching with medium-soft rock. In addition, during the preparation process, liquid ammonium nitrate can be used for preparation, and the entire production process can be completed by self-heating of liquid ammonium nitrate; when solid ammonium nitrate is used for production, the water phase is heated to a maximum of 50°C, with lower energy consumption and more environmental protection.

[0012] The gelling agent, liquid fuel and auxiliary combustible agent are mixed and stirred to form a suspension and then added into the aqueous solution.

[0013] Furthermore, the liquid fuel is a water-soluble fuel, such as ethylene glycol, and the gelling agent is one of guar gum, sesbania gum, and polyacrylamide. Under the action of the cross-linking agent, they are mutually bonded and cross-linked to form a stable molecular structure in a network shape.

[0014] Furthermore, the liquid fuel is directly added to the aqueous solution, and the gelling agent and the auxiliary combustible agent are mixed into the solution using a water-powder mixer.

[0015] Compared with the traditional adding method, changing the adding method of the gelling agent can reduce the agglomeration of the gelling agent and improve the mixing effect of the water gel explosive.

[0016] Furthermore, the temperature of the aqueous solution is ≤50°C, and the temperature after adding the liquid fuel is also ≤50°C.

[0017] Controlling the temperature below 50°C can ensure that solid materials such as ammonium nitrate are completely dissolved, while also ensuring production safety.

[0018] Furthermore, the amount of sensitizer added is changed to adjust the charge density, and the density adjustment range is 0.3-1.25 g / cm 3 .

[0019] The sensitizer is a mixed solution of sodium thiocyanate and sodium nitrite.

[0020] Furthermore, the chemical formula of the calcium nitrate is Ca(NO3)2·4H2O, which is an auxiliary oxidant.

[0021] The calcium nitrate acts as an auxiliary oxidant and reduces the crystallization point of ammonium nitrate. Reducing the crystallization point of ammonium nitrate can prevent ammonium nitrate from crystallizing under low temperature conditions, improve the stability of water gel explosives, and further improve the water resistance of explosives.

[0022] Furthermore, the on-site mixed water gel explosive prepared by the preparation method is composed of the following raw materials by mass fraction: ammonium nitrate: 45-70%; calcium nitrate: 10-20%; liquid fuel: 7-20%; water: 9-15%; gelling agent: 0.7-1.0%; additives: 0.2-0.5%.

[0023] Compared with the prior art, the preparation method of on-site mixed water gel explosive disclosed in the present invention fills the blank of on-site mixed water gel explosive; at the same time, the process flow of the preparation method is simple, which is basically similar to the existing emulsion explosive production process flow, and the equipment used is universal with the emulsion explosive production equipment, and the existing emulsion explosive production line or ground station can be simply modified to put into production; the preparation method of the present invention can use liquid ammonium nitrate for preparation, and the entire production process can be completed by self-heating of the liquid ammonium nitrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a preparation flow chart of a method for preparing on-site mixed water gel explosive using a water-powder mixer;

[0025] Figure 2 The present invention is a flow chart of the preparation of a method for preparing on-site mixed water gel explosives, wherein the gelling agent, the auxiliary combustible agent and the liquid fuel are mixed and stirred;

[0026] Figure 3 This is the experimental effect diagram of direct addition of gelling agent.

[0027] Figure 4 This is a test result diagram of the gelling agent added after being mixed with liquid fuel. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0029] Please refer to the instruction manual Figure 1 and Figure 2 The present invention discloses a method for preparing a mixed water gel explosive on site, comprising the following steps:

[0030] S1: adding ammonium nitrate, calcium nitrate, sodium nitrate and additives into water and stirring to dissolve, and preparing an aqueous phase solution after they are completely dissolved;

[0031] S2: adding liquid fuel, gelling agent and auxiliary combustible agent to the aqueous solution obtained in step S1 and stirring to form a viscous colloid to obtain a thickened mother solution;

[0032] S3: adding the porous granular ammonium nitrate to the thickened mother liquor obtained in step S2 and stirring, so that the porous granular ammonium nitrate is evenly dispersed in the thickened mother liquor to obtain a semi-finished product;

[0033] S4: adding a sensitizer and a cross-linking agent to the prepared semi-finished product, and mixing them evenly to form the on-site mixed water gel explosive.

[0034] Preferably, the liquid fuel is directly added to the aqueous solution, and the gelling agent is mixed into the solution using a water-powder mixer.

[0035] More preferably, the gelling agent is added to the liquid fuel, stirred evenly to form a suspension, and then added to the aqueous solution.

[0036] Gelling agent addition experiment

[0037] The test steps and results are as follows:

[0038] Weigh 2800g of ammonium nitrate, 1200g of calcium nitrate, 30g of additives, and 810g of water, mix and stir, and after the solid materials are completely dissolved, divide the aqueous phase solution into two parts, A and B, for later use;

[0039] Accurately weigh two portions of 64g guar gum and set aside;

[0040] Add 492 g of liquid fuel to the A# aqueous phase solution, stir and mix evenly, then slowly add the weighed guar gum to the solution while stirring;

[0041] The weighed guar gum was mixed with 492 g of liquid fuel and stirred until a suspension was formed, and then added to the B# aqueous phase solution and stirred evenly;

[0042] After a viscous colloid is formed, observe the mixing effect of the gelling agent. Figure 3 and 4 , the results are as follows:

[0043] A# A large amount of lumpy gelling agent can be seen with the naked eye, and the mixing effect is poor.

[0044] B# has no obvious lumpy gelling agent and has excellent mixing effect.

[0045] The method for preparing the on-site mixed water gel explosive of the present invention can significantly improve the agglomeration phenomenon of the gelling agent during the addition process, thereby improving the stability of the water gel explosive and avoiding the decrease in water resistance of the explosive due to agglomeration of the gelling agent. Specific embodiment 1

[0047] Taking the production of 1000kg on-site mixed water-gel explosives as an example, solid ammonium nitrate is selected to prepare the aqueous solution. The raw material ratio, by weight percentage, is: 35% ammonium nitrate, 12% calcium nitrate, 11% ethylene glycol, 2% rice husk powder, 11% water, 0.8% gelling agent, 0.2% additive, and 28% porous granular ammonium nitrate.

[0048] The first step is to mix ammonium nitrate, calcium nitrate, water and additives according to a proportion, heat and stir to prepare an aqueous solution, and set the temperature to 50°C.

[0049] The second step is to mix the gelling agent, rice husk powder and ethylene glycol according to the proportion, stir to form a suspension, then add it into the aqueous phase solution and stir for 15 minutes to obtain a viscous thickening mother solution.

[0050] The third step is to add the porous granular ammonium nitrate weighed according to the ratio into the thickened mother liquor, and stir for 15 to 20 minutes to evenly mix the porous granular ammonium nitrate and the thickened mother liquor to obtain a semi-finished product.

[0051] Step 4: Add 3% of the sensitizer and 2% of the cross-linking agent into the semi-finished product and mix them evenly to obtain the on-site mixed water gel explosive. Specific embodiment 2

[0053] Taking the production of 1000kg limited-production mixed water-gel explosives as an example, 95% concentration of liquid ammonium nitrate is selected to prepare the aqueous phase solution. The raw material ratio is: 40% liquid ammonium nitrate, 12% calcium nitrate, 12% ethylene glycol, 1% straw powder, 9% water, 0.8% gelling agent, 0.2% additive, and 25% porous granular ammonium nitrate.

[0054] The first step is to mix liquid ammonium nitrate, calcium nitrate, water and additives according to a proportion, stir to obtain an aqueous solution, and set the insulation temperature to 50°C.

[0055] Step 2: Add ethylene glycol into the aqueous solution according to the proportion and stir to mix.

[0056] The third step is to use a water-powder mixer to add the gelling agent and straw powder into the solution and stir for 15 minutes to obtain a viscous thickening mother solution.

[0057] Step 4: Add the porous granular ammonium nitrate weighed according to the ratio into the thickened mother liquor, stir for 15 to 20 minutes to evenly mix the porous granular ammonium nitrate and the thickened mother liquor to obtain a semi-finished product.

[0058] Step 5: Add 3% of sensitizer and 2% of cross-linking agent into the semi-finished product and mix them evenly to obtain on-site mixed water gel explosive.

[0059] The present invention provides a method for preparing on-site mixed explosives, which has the following beneficial effects:

[0060] The preparation method of the present invention has a simple process flow, which is basically similar to the process flow of emulsion explosive production. The equipment used is common to the emulsion explosive production equipment, and the existing emulsion explosive production line or ground station can be put into production by simple modification.

[0061] The preparation method of the present invention can be prepared using liquid ammonium nitrate, and the entire production process can be completed by self-heating of the liquid ammonium nitrate; when solid nitric acid is used for production, the water phase is heated to a maximum of 50° C., and the energy consumption is low and more environmentally friendly.

[0062] The thickening mother solution and semi-finished product prepared by the invention have the characteristics of good stability, long storage period and high transportation safety.

[0063] The on-site mixed water gel explosive prepared by the invention fills the blank of domestic on-site mixed water gel explosive, and has the characteristics of good water resistance, large density adjustment range and high matching degree with medium soft rock.

[0064] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for preparing on-site mixed water gel explosive, characterized in that: The preparation method comprises the following steps: S1: adding ammonium nitrate, calcium nitrate and additives into water, heating and stirring, and preparing an aqueous solution after they are completely dissolved; S2: adding liquid fuel, gelling agent and auxiliary combustible agent into the aqueous phase solution and stirring to form a viscous colloid to obtain a thickened mother solution; S3: adding porous granular ammonium nitrate and auxiliary combustible agent into the thickened mother liquor and stirring, so that the porous granular ammonium nitrate and auxiliary combustible agent are evenly dispersed in the thickened mother liquor to obtain a semi-finished product; S4: adding a sensitizer and a cross-linking agent to the semi-finished product, and mixing them evenly to form an on-site mixed water gel explosive.

2. The method for preparing the on-site mixed water gel explosive according to claim 1, wherein: In the step S2, The gelling agent, liquid fuel and auxiliary combustible agent are mixed and stirred to form a suspension and then added into the aqueous solution.

3. The method for preparing the on-site mixed water gel explosive according to claim 1, characterized in that: In the step S2, Liquid fuel is directly added into the aqueous solution, and gelling agent and auxiliary combustible agent are mixed into the solution using a water-powder mixer.

4. The method for preparing the on-site mixed water gel explosive according to claim 1, wherein: In the step S2, The temperature of the aqueous phase solution is ≤50°C, and the temperature is also ≤50°C after adding the liquid fuel.

5. The method for preparing on-site mixed water gel explosive according to claim 1, characterized in that: In the step S4, The charge density can be adjusted by changing the amount of sensitizer added. The density adjustment range is 0.3~1.25g / cm 3 .

6. The method for preparing on-site mixed water gel explosive according to claim 1, characterized in that: The chemical molecular formula of the calcium nitrate is Ca(NO3)2·4H2O, and it is an auxiliary oxidant.

Images