JP2002356394A - Explosive composition and its manufacturing process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the detonation performance and the accuracy of design for blasting of a site-mixing emulsion explosive, to reduce its amount of use and to facilitate its safe preparation at the site. SOLUTION: The bulk density is made not more than 0.4-0.8 by adding a water-soluble acidic substance to an aqueous solution of an oxidizing agent in emulsion phase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an explosive composition for use in industrial blasting such as crushed stone, mining, and tunnel excavation, and a method for producing and using the same. More particularly, the present invention relates to an explosive composition excellent in gas foaming reaction, and a method for producing and using the same.

[0002]

2. Description of the Related Art Explosives can be loaded at a blasting site in Japan by manual loading by a worker in the case of a cartridge type explosive, or by manual loading by a liquid nitrous acid explosive (hereinafter, ANFO). Machine loading by loaders has been performed. However, by hand, it is necessary to approach the blast hole, and it is dangerous and the time required for loading is long, and ANFO has poor water resistance, poor reactivity, and crushing effect. Unfortunately, many improvements have been sought, such as aftergas blasting when underground blasting.

In response to this, recently, premixing bulk emulsion explosives manufactured as explosives at explosive manufacturing plants have been used at several sites,
Due to its fluidity, mechanical loading is being performed, and reductions in loading time, labor savings, and safety are being pursued. However, this premixing bulk emulsion explosive is often difficult to load into a blast hole with an appropriate amount, and explosives are often used more often than cartridge-type explosives, resulting in increased costs and destruction beyond the planned cross section. There are problems such as inviting.

[0004] In order to reduce the amount of explosive used, there is a method of reducing the bulk specific gravity of a bulk emulsion explosive. However, in order to reduce the bulk specific gravity, for example, when the added amount of hollow particles is increased, the viscosity increases. However, there is a problem that the fluidity is reduced and it is difficult to load the machine safely. It has been reported that the bulk specific gravity of a premixing bulk emulsion explosive manufactured as an explosive at this explosive manufacturing plant is about 1.15 to 1.25. Overseas, bulk emulsion explosives are already commonly used, but as a base material for bulk emulsion explosives, the emulsion phase (hereinafter referred to as EP), which is not explosive and is simply treated as a dangerous substance in many countries Is manufactured in a factory and mixed with an aqueous foaming agent solution at the blasting site to make fine bubbles contained in the EP and sensitize it, and a method for producing a site-mixing bulk emulsion explosive has been developed and used at many sites. ing. This method is an extremely safe technology because it is in a blast hole that changes into an explosive bulk emulsion explosive, and because EP is not explosive in production, transportation, and storage, etc. Are known.

[0005] Since the bulk mixing explosive of the present invention performs a foaming reaction after loading the machine and reduces the bulk specific gravity of the explosive, the bulk specific gravity can be reduced more than that of the premixing bulk emulsion explosive, and the minimum bulk specific gravity of the explosive is 0. About 0.8 to 1.2 are reported. However, this site-mixing bulk emulsion explosive also uses more than cartridge-type explosives,
When the mixing of EP and the foaming agent is not good or when the temperature at the time of foaming is low, sufficient bubbles are not generated, and there is a problem that a bulk emulsion explosive having poor reactivity is produced.

[0006]

The present invention relates to a bulk mixing explosive for cytomixing, and more particularly to an explosive composition capable of effectively promoting a foaming reaction during EP, having high reactivity and reducing the amount of explosive used. It is intended to provide a method.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by adding a water-soluble acidic substance to an aqueous solution of EP oxidizing agent, the foaming reaction is effectively promoted. The present invention was found to be able to perform the mixing more uniformly and safely by using a static mixer at the time of on-site mixing, and completed the present invention. The cytomixing emulsion explosive of the present invention is a cytomixing bulk emulsion explosive, wherein the pH of the oxidizing agent aqueous solution is 2 to 4.

In producing the oxidizing agent aqueous solution, the pH value of the oxidizing agent aqueous solution is adjusted to the above-mentioned range of 2 to 4 using its own components such as ammonium nitrate, sodium nitrate, calcium nitrate and potassium nitrate. .
This pH value is preferably about 3. This pH adjustment is desirably performed by adding a water-soluble acidic substance to the oxidizing agent aqueous solution in the emulsion phase. The other site-mixing emulsion explosive of the present invention is a site-mixing bulk emulsion explosive characterized by having a bulk specific gravity at the time of detonation of 0.4 to 1.1 at 10 ° C. or lower. This bulk specific gravity is 0.4 to 0.8 at 10 ° C. or less.
Desirably less than.

[0009] Still another preferred embodiment of the present invention is a bulk explosive for site mixing, wherein a bulk specific gravity at the time of initiation of the explosion is less than 0.4 to less than 0.8 at 35 ° C or less. This bulk specific gravity is
Desirably, it is less than 0.4 to less than 0.6 at 35 ° C or less. The bulk specific gravity of the cytomixing bulk emulsion explosive is adjusted by increasing the concentration of the blowing agent in the aqueous foaming agent solution described below, or by adjusting the pH of the EP oxidizing agent aqueous solution by adding a water-soluble acidic substance.

[0010] The foaming reaction of the bulk mixing explosive is initiated by mixing EP with an aqueous solution of a foaming agent. Examples of the foaming agent include peroxides such as hydrogen peroxide and sodium nitrite. Nitrite, N,
Nitrosamines such as N 'dinitrosopentamethylenetetramine, alkali metal borates such as sodium borate,
There are bases such as carbonates including sodium carbonate. Particularly widely used are nitrous acid and its salts, which react under acidic conditions to generate nitrogen gas bubbles, with sodium nitrite being the most suitable blowing agent. Examples of the accelerator for the nitrite foaming reaction include thiocyanate, iodide, sulfamic acid or a salt thereof, thiourea, and urea.

In the explosive composition of the present invention, nitric acid, acetic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, etc. are added to the EP oxidizing agent aqueous solution in order to more effectively and surely promote the foaming reaction. Maleic acid, fumaric acid, citric acid,
Water-soluble acidic substances such as dicarboxylic acids such as malic acid, tartaric acid and glucaric acid can be added. In this,
In consideration of economy and the like, nitric acid, acetic acid, citric acid, malic acid, tartaric acid, and fumaric acid are preferable. If you want to add
It is added so that the pH of the oxidizing agent aqueous solution becomes 2 to 4. This pH value is preferably about 3.

Further, in order to sufficiently exhibit the performance of the explosive, it is appropriate that the foamed foam has a diameter of 20 μm to 800 μm, and needs to be uniformly dispersed in the explosive. is there. For that purpose, it is important to make the droplets of the aqueous foaming agent solution smaller and uniformly disperse them in the EP when mixing the EP with the aqueous foaming agent solution. E
Since P is a water-in-oil type emulsion, its surface is covered with an oil phase and is hardly mixed with an aqueous foaming agent solution.

[0013] Therefore, the mixing device to be mixed on site,
Special mixing equipment including safety is required. In the present invention,
Use a static mixer for safety. Examples of usable static mixers include orifice type, Kenix type, Hi-Mixer of Toray, and SMV of Sulzer.
Types, SMI type, SMF type, SMX type and SMXL type, ISG type and LPD type of Ross, stator tube type of TAH, spiral mixer, NRA type of Nippon Sosei Industries, etc.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the following, a description will be given of experiments on the presence / absence of addition of a water-soluble acidic substance, bulk specific gravity at the time of detonation, detonation / non-explosion, and bulk density and design accuracy of blasting.

[0015]

EXAMPLE As an oxidizing agent aqueous solution, ammonium nitrate (7
4.5% by weight) and water (20% by weight) were dissolved and mixed at 75 ° C. Further, light oil (4% by weight) and sorbitan sesquioleate (1.5% by weight) were mixed as a fuel phase and heated to 70 ° C. Thereafter, the oxidizing agent aqueous solution and the fuel phase were emulsified to obtain EPs of Examples 1 to 10. In particular, in Examples 2 to 10, the acidic substances shown in Table 1 were added to and dissolved in the oxidant aqueous solution immediately before emulsification of the oxidant aqueous solution and the fuel phase so that the pH became about 3.

[0016] Sodium nitrite was dissolved in water to produce an aqueous foaming agent solution. Table 1 shows the concentration of sodium nitrite.
A steel pipe having an inner diameter of about 43 mmφ was used as a blast hole, and a bulk emulsion explosive loading device of ORICA was used for loading. In addition, a static mixer was installed at the end of the loading device hose for mixing the EP and the aqueous foaming agent solution. At the bottom of the steel pipe, 100 g of a cartridge-type wet explosive (trade name "Sanbex Enoki") was loaded as a booster, and the bulk emulsion explosives of Examples and Comparative Examples were loaded on the steel pipe. After 30 minutes, the length of the explosive was measured, and the bulk specific gravity of the explosive was calculated. In addition, a detonation test was performed to confirm whether or not the booster was detonated. Table 1 shows the results.

[0017]

Comparative Example EP was prepared in the same manner as in the example. However, no water-soluble acidic substance was added. An ignition test similar to that of the example was performed. Table 1 shows the results.

[0018]

[Field Example] In a tunnel of hard rock having a cross section of about 50 m 2, it was blasted using a site-mixing bulk emulsion explosive having a bulk specific gravity of 0.6 at the time of detonation. The number of holes and the charge length after foaming were the same as in the comparative example. This blast was performed 10 times, and the average flea trace rate was measured and calculated to be 60%. In addition, the length of progress per blast was almost the same as the field comparison example. The flea mark ratio is a ratio of a mark (flea mark) in which the outermost blast hole remains in a semi-cylindrical shape after blasting, and is calculated by the following formula. Flea mark rate = (cumulative flea mark length) / (one blast progress length × number of outermost holes) × 100 The fact that flea marks are left means that it is crushed at the section to be crushed. It can be said that as the flea trace rate is larger, the crushing is performed at the section to be crushed and the blast design accuracy is higher.

[0019]

[Comparative Example on Site] The blasting was performed under the same conditions as in Example 1 on site except that the bulk specific gravity of the cytomixing bulk emulsion explosive was 0.9. The post-flea rate after 10 blasts was 30%.

[0020]

[Table 1]

From Table 1, it can be seen that the explosive composition of the present invention performs a sufficient foaming reaction up to a bulk specific gravity that can be detonated even at a low temperature. Also, from Table 1 and the results of the field tests, it can be seen that the bulk specific gravity of the bulk emulsion explosive was sufficiently reduced, and optimum blasting could be performed.

[0022]

According to the present invention, the foaming reaction in a low-temperature environment is improved, the bulk specific gravity of the bulk emulsion explosive is reduced, the explosive consumption is reduced, and safe on-site production is made possible. .

Claims (7)

[Claims] 1. An explosive for mixing a bulk emulsion, wherein the pH of the aqueous oxidizing agent solution is 2 to 4. 2. The explosive according to claim 1, wherein a water-soluble acidic substance is added to an aqueous solution of the oxidizing agent in the emulsion phase. 3. A bulk mixing explosive for cytomixing, wherein the bulk specific gravity at the time of initiation is 0.4 to 1.1 at 10 ° C. or lower. 4. A bulk mixing explosive for cytomixing, wherein the bulk specific gravity at the time of detonation is not more than 0.4 to less than 0.8 at 35 ° C. or less. 5. The explosive according to claim 1, which is produced by mixing using a static mixer. 6. A method of manufacturing a bulk explosive for cytomixing, wherein the explosive for cytomixing according to claim 1 is mixed and manufactured using a static mixer. Method. 7. A blasting method which is carried out by using the bulk mixing explosive according to any one of claims 1 to 5.