JP2002348187A - Explosive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop an explosive composition having enough explosive property, hardly being dissolved in water even in such a situation that water penetrates into bore holes. SOLUTION: The explosive composition consists of a porous prill ammonium nitrate having a bulk specific gravity of 0.50-0.75, fuel oil, and a sodium carboxymethyl cellulose or a sodium polyacrylate as the thickening stabilizer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to crushed stone, mining, coal mining,
The present invention relates to an explosive composition widely used for industrial blasting work such as digging on a steep road. More specifically, the present invention relates to a granular explosive composition that can be used by being directly loaded into a perforation or the like.

[0002]

2. Description of the Related Art As explosives used in industrial blasting operations, dynamite, hydrous explosives, nitrate explosives, and nitrate oil explosives (hereinafter referred to as ANFO explosives) are well known. Of these explosives, the ANFO explosive is an explosive that can be manufactured relatively easily, and is well known as an inexpensive and highly safe explosive compared to other industrial explosives. Also, ANF
The O explosive is composed of a fluid particulate material and can be directly poured into the perforation or loaded by a loading machine such as a loader. For these reasons, ANFO explosives are very widely used.

It is well known that the reactivity of porous prill ammonium nitrate (hereinafter referred to as porous prill nitrate) is considerably lower than that of explosive compounds such as nitroglycerin and nitroglycol. Therefore, ANFO explosives, in which porous prill nitrate often accounts for 90% by weight or more of the entire explosive as an oxidizing agent, are less powerful than other industrial explosives, but are widely used because they are inexpensive and stable. Have been. In addition, the detonation sensitivity is stipulated in the PVC method or the carton method as not to completely detonate with a No. 6 detonator. Due to its low sensitivity, storage and transport in a 25 kg heavy bag, for example, are permitted.

On the other hand, ammonium nitrate is about 1 at 0 ° C. per 100 g of water.
It dissolves in 20 g and at about 100 ° C. about 950 g, and is relatively easily dissolved in water. Therefore, in the case of ANFO explosives, if water is present in the blast holes, groundwater infiltrates, or water penetrates into the holes in rainy weather, ammonium nitrate easily dissolves in the holes and light oil separates. May lose explosive properties. Therefore, under such conditions, a package explosive such as water-resistant dynamite or a water-containing explosive is used, or an (packaged) ANFO explosive previously loaded in a waterproof packaging material such as a polytube pharmaceutical cylinder is used. Or be done.

[0005]

However, in the former case, the explosive used is more expensive than the ANFO explosive, and the blasting cost increases. Also, the latter case not only loses its significance of being easily loaded in bulk, but also creates a gap between the packaged explosive and the perforated wall,
A sufficient blasting effect cannot be obtained as compared with the case where the ANFO explosive is directly loaded into the perforation. In addition, the ANFO explosive packaged in such a polytube is damaged by the sharp stones of the perforated wall when charging the perforation into the perforation, and as a result, water penetrates into the inside of the package, so that the ANFO explosive absorbs moisture. Explosion performance may be lost. In order to solve these problems, a method of maintaining a certain level of water resistance by adding a thickening stabilizer or a plant mucilage to a conventional ANFO explosive has already been known. It has been confirmed that the explosion performance may be reduced. In view of these circumstances, the present invention makes use of the fluidity during the charging operation, which is an advantage of the ANFO explosive, and the simplicity of the manufacturing process as much as possible. It is an object of the present invention to provide a granular explosive that has a higher power and has a property of maintaining high explosive performance even under immersion conditions.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, an explosive composition containing a specific porous prill nitrate, a fuel oil and a thickening stabilizer has been developed by ANFO. Conventional ANFO explosives and ANs with certain water resistance, without compromising the inherent advantages of the explosives
The inventors have found that the water resistance and power are remarkably improved as compared with the FO explosive, and completed the present invention.

That is, according to the present invention, (1) the bulk specific gravity is 0.5
An explosive composition comprising 0 to 0.75 of porous prilled ammonium nitrate, a fuel oil and a thickening stabilizer, (2) the thickening stabilizer has a particle size of 0.01 to 3 mm (1) The explosive composition according to (1) or (2), wherein the content of the thickening stabilizer is 2.0 to 20.0% by weight of the entire explosive composition. object,
(4) Porous prill ammonium nitrate has an oil absorption of 5.
The explosive composition according to any one of the above (1) to (3), which has a hardness of 0 to 24.0% and a hardness of 0.1 to 10.0.
(5) Particle size of all porous prill ammonium nitrate
The explosive according to any one of the above (1) to (4), wherein the explosive having a size of 36 mm or more and the content of 0.98 mm or less are contained in proportions of 0.5% by weight or more and 1.0% by weight or less, respectively. The explosive according to any one of (1) to (5), wherein the composition, (6) the porous prill ammonium nitrate, is a mixture with porous prill ammonium nitrate containing fine hollow particles in a substrate, or a pulverized product thereof. The composition, (7) the explosive composition according to any one of the above (1) to (6), wherein the 0.2% by weight aqueous solution of the thickening stabilizer has a viscosity of 20 to 10000 mPa · s at 20 ° C. The present invention relates to the explosive composition according to any one of the above (1) to (7), wherein the thickening stabilizer is sodium carboxymethylcellulose, sodium polyacrylate, or a mixture thereof.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The porous prill nitrate used in the explosive composition of the present invention has a bulk specific gravity of 0.55 to 0.75, preferably 0.5 to 0.75.
Those that are between 8 and 0.70 are used. Porous prill nitrate is generally used in the range of 65 to 96% by weight, preferably 75 to 95% by weight, based on the entire explosive composition.
Further, the porous prill nitrate used in the explosive composition of the present invention has an oil absorption of usually 5.0 to 24.0%, preferably 7 to 20%, and a hardness of usually 0.1 to 10.0%, preferably Is preferably 0.1 to 5.0%. Further, as porous prill nitrate used in the explosive composition of the present invention, those having a particle size of not less than 2.36 mm and 0.96 mm
The following are preferably 0.5% by weight or more and 1.0% by weight or less, respectively. Further, as the porous prill nitrate used in the explosive composition of the present invention, a porous prill nitrate containing fine hollow particles in the porous prill nitrate is used, and the fine hollow particles are 1.0 × with respect to the porous prill nitrate. It is preferable that it is contained in the porous prill nitrate in the range of 10 ^{-6 to} 10.0% by weight, preferably 0.05 to 10.0% by weight, and porous prill nitrate obtained by pulverizing the same can also be used. In the explosive composition of the present invention, the fine hollow particles contained in the porous prill ammonium nitrate are mainly used as a specific gravity adjuster or the like, and specific examples of the fine hollow particles that can be used include resin microballoons, There are natural or synthetic porous substances such as glass balloons, metal hollow particles, and shirasu balloons, and these are used alone or in combination of two or more. In the explosive composition of the present invention, among the above, resin microballoons are preferred.

In the explosive composition of the present invention, porous prill nitrate (preferably, porous prill nitrate having the above-mentioned particle size distribution) and its pulverized product can be mixed in any ratio, but preferably, porous prill nitrate is used. Is 20 to 80% by weight. As described above, the porous prill nitrate can be crushed by itself or mixed with a crushed product to have a desired bulk specific gravity.

The bulk specific gravity of porous prill nitrate is JIS K
It is measured according to the method specified in -6721. That is, a certain amount of porous prill nitrate of a sample is dropped from a certain height into a cylindrical cup set on a support base using a funnel having a damper at a lower part supported by a support rod, and placed on the cup. After removing the ammonium nitrate of the raised sample porous prill, it is measured by weighing the sample of porous prill nitrate in the cup. Specifically, the upper end diameter 90
mm, the lower end 15mm in diameter, 115mm in height funnel,
Depth 80 mm above funnel bottom and support table, volume 100 cm ³
Is installed so that the distance from the top of the cup is 45mm,
Put 100g of porous prill nitrate sample into the funnel,
Slide the damper to drop the sample of porous prill nitrate into the glass. Carefully take care not to vibrate, and use a spatula to remove the porous prilled ammonium salt of the sample raised on the cup so that it is horizontal at the same height as the top of the cup. The porous prill nitrate of the sample adhering to the outside of the cup is removed, and the weight of the porous prill nitrate of the sample in the cup is weighed with a direct reading balance. After the above measurement, the bulk specific gravity is calculated by the following equation (1).

Bulk specific gravity = sample weight (g) / 100 (cm ³ ) (1)

The oil absorption of porous prilled ammonium nitrate is measured by immersing a fixed amount of sample nitric acid in light oil for a certain period of time, performing suction filtration, and observing the adsorption amount of light oil from the weight difference before and after the test. Specifically, 50 g of sample nitrate is 40 m in diameter.
m, placed in a glass filter (11G-1) having a depth of 50 mm, weighed with an upper plate direct balance, and set in a vacuum device. Next, 40 ml of light oil is poured into the glass filter, and the mixture is thoroughly stirred with a thin rod to achieve mixed contact between ammonium nitrate and light oil. After standing for 5 minutes, the cock provided at the lower part of the glass filter is opened, and light oil is allowed to flow naturally for 2 minutes. Subsequently, suction with a vacuum pump for 5 minutes (flow rate: about 30 l / mi)
After n), the glass filter containing the sample ammonium adsorbed with light oil is weighed with an upper direct reading balance. Here, the increased amount is the absorbed amount of light oil. After the above measurement, the ratio (%) of the light oil adsorption (g) to 50 g of the original sample nitrate is indicated as the oil absorption (%). The calculation formula is as shown in the following formula (2).

[0013] Oil absorption rate (%) = light oil adsorption (g) / ammonium nitrate sample 50 (g) x 100 (2)

The oil absorption rate of ammonium nitrate mainly depends on the volume and effective diameter of the pores distributed inside the particles. For example, if the pore volume is large, the space for retaining light oil inside the particles is large. Therefore, the oil absorption rate becomes large.

The hardness of porous prill nitrate is measured by mechanically pulverizing a fixed amount of porous prill ammonium nitrate under a predetermined condition using a hardness measuring device and measuring the amount of the pulverized ammonium nitrate. The apparatus used for the measurement is a funnel for sample injection, a flow pipe (inner diameter 16 mm, length 175 mm) connected to the compressed air inlet (inner diameter 4 mm, length 55 mm), and the upper part of these connections and the funnel are connected vertically. Sample injection tube (inner diameter 12 mm,
(Length: 52 mm) and a sample pulverizing tube (inner diameter: 50 mm, length: 315 mm) vertically connected to the flow tube.

100 g of porous prill nitrate from which powder was removed with a 35 mesh sieve was dropped from a funnel through a sample injection tube into a flow tube, and compressed air (4 kg) flowing from an inflow hole was introduced.
/ Cm ² ), the sample collides with the inner wall of the pulverizing tube through the flow tube to pulverize the porous prill nitrate. Porous prill ammonium nitrate after sifting is sieved with 35 mesh, and +35 m
The amount of esh (N) is weighed, and the original porous prill nitrate 10
It is expressed as the ratio (%) of the amount of powder to 0 g. The calculation formula is as shown in the following formula (3).

Hardness (%) = 100 (g) −N (g) (3)

Particle size distribution of porous prill ammonium nitrate (% by weight)
Is measured by passing a certain amount of porous prill nitrate through various sieves having different sieves, and measuring the residual weight on the sieve net for each sieve.

As the fuel oil used in the explosive composition of the present invention, it is preferable to use a fuel oil which is liquid at the time of mixing. Examples of usable fuels include mineral oils such as light oil and kerosene, vegetable oils, animal oils and the like.

In addition, methyl alcohol,
Alcohols such as ethyl alcohol, waxes such as paraffin wax and microcrystalline wax, and nitro compounds such as dinitrotoluene and dinitroxylene can be used alone or in combination as a fuel oil.
High melting point fuel oils can be used by mixing with porous prill nitrate above the temperature at which it becomes liquid.

The amount of the fuel oil used in the explosive composition of the present invention is usually in the range of 2.5 to 25% by weight, preferably 4 to 10% by weight of the whole explosive.

The thickening stabilizer used in the explosive composition of the present invention is, for example, a stabilizer, a gelling agent, a thickening agent, a water absorbing agent, etc. used in the food industry, etc. Moisture of the added substance system when added causes thickening or gelation, preventing separation and sedimentation of the substance dispersed in the system, and stabilizing the entire system. Any synthetic substance can be used, and these can be used alone or in combination of two or more. Specific examples of the thickening stabilizer that can be used include sodium alginate, sodium carboxymethylcellulose, sodium polyacrylate, methylcellulose, sodium starch glycolate and the like. In the explosive composition of the present invention, all of the above substances are effective, but sodium carboxymethylcellulose and sodium polyacrylate are particularly preferable.

The thickening stabilizer used in the explosive composition of the present invention has a problem that if the particles are too large, only a partial effect is exhibited, and if the particles are too fine, it is difficult to handle.
Preferably 0.01 to 3 mm, more preferably 0.0
Those having a size of 5 to 1.0 mm are used.

If the amount of the thickening stabilizer used in the explosive composition of the present invention is too small, the effect does not appear, and if it is too large, the performance as an explosive may be reduced or the cost may be increased. , Preferably 1 to 30% by weight, more preferably 2 to 20% by weight, based on the entire explosive.
Used in the range.

The viscosity of the thickening stabilizer used in the explosive composition of the present invention is measured, for example, by dissolving a certain amount of the thickening stabilizer in water and reaching a certain temperature by using a DV type viscometer. Can be measured. Specifically, 0.4 g of the thickening stabilizer is precisely weighed in a 300 ml Erlenmeyer flask, and water is gradually added to bring the total amount to 200 g. After leaving for 1 hour, the mixture is completely melted using a glass rod, sealed, and placed in a thermostat at 20 ° C. After confirming that the temperature of the solution reached 20 ° C., about 3
Shake the Erlenmeyer flask for 0 seconds and transfer to a beaker. After stirring with a glass rod, use a DV type viscometer for 1
The viscosity is measured at a rotation speed of 60 rotations per minute. As the thickening stabilizer used in the present invention, the viscosity of a 0.2% by weight aqueous solution at 20 ° C. is preferably 20 to 10000 mPa · s as measured by a DV-type rotational viscometer at 60 rpm.
More preferably, those having 20 to 4000 mPa · s are used.

The explosive composition of the present invention can be subjected to measures for preventing generation of static electricity, if necessary. For example, various surfactants known as water-soluble or oil-soluble antistatic agents (JP-A-55-51794, JP-A-11-147784), starches (JP-A-10-291883),
Additives such as fatty acid amides (JP-A-11-322481) can be added.

The explosive composition of the present invention may optionally contain an oxidizing agent other than porous prill ammonium nitrate, for example, potassium nitrate or perchlorate, or a powdered fuel such as wood powder or aluminum powder, or other additives. It is possible.

The explosive composition of the present invention is prepared by uniformly mixing the porous prill nitrate and the fuel oil, the thickening stabilizer and, if necessary, other additives in the above-mentioned ratio with a mixer such as a kneader or a rotary mixer. Manufactured by
At this time, the fuel oil may be added after mixing the porous prill nitrate and the thickening stabilizer, or the fuel oil and the porous prill nitrate may be mixed and then the thickening stabilizer may be mixed. Further, a metal powder or an additive can be further added. In addition, other mixers can be used as long as they have stirring and mixing functions.

The explosive composition of the present invention prevents dissolution of ammonium nitrate by the thickening stabilizer in the explosive composition without impairing the original advantages of the ANFO explosive and even when water enters the perforations. And has the property of being very powerful compared to conventional ANFO explosives.

[0030]

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, parts are parts by weight.

Example 1 A material having a bulk specific gravity of 0.63, an oil absorption of 16.8%, a hardness of 3.4%, a particle size of not less than 2.36 mm and a particle size of not more than 0.98 mm were 0.7% by weight and 0%, respectively. 80 parts by weight of porous prill nitrate (80 parts) and 5 parts of No. 2 light oil were mixed at room temperature using a rotary mixer (concrete mixer) at a speed of 60 rotations per minute for 3 minutes, and then the average particle size was about 0.2 mm.
And the viscosity at 20 ° C. of the 0.2% by weight aqueous solution is 4
5 parts of 0 mPa · s sodium carboxymethylcellulose, 5 parts of sodium polyacrylate having an average particle size of about 0.1 mm and a 0.2% by weight aqueous solution having a viscosity of 500 mPa · s at 20 ° C. for 1 minute Mix and
100 parts of the explosive composition of the present invention were obtained.

Example 2 Bulk specific gravity of 0.58, oil absorption of 12.0%, hardness of 3.0%, particle size of not less than 2.36 mm and not more than 0.98 mm were 53.3% by weight and 0%, respectively. 85% by weight of porous prill nitrate containing 0.30% by weight of fine hollow particles and 0.2% by weight of an average particle size of about 0.2 mm.
10 parts of sodium polyacrylate having a viscosity of 480 mPa · s at 20 ° C. of the aqueous solution is placed in a horizontal kneader container equipped with a sigma blade at room temperature, and 5 parts of No. 2 light oil is further added. The mixture was mixed at a speed for 5 minutes to obtain 100 parts of the explosive composition of the present invention.

Example 3 87 parts of the same porous prill nitrate as in Example 2 and No. 2 light oil 3
Parts at room temperature using a rotary mixer (concrete mixer) at a speed of 80 revolutions per minute for 3 minutes, then the viscosity at 20 ° C. of a 0.2% by weight aqueous solution having an average particle size of about 0.1 mm Was added simultaneously and mixed at the same rotation speed for 1 minute to obtain 100 parts of the explosive composition of the present invention.

Comparative Example 1 Bulk specific gravity 0.78, oil absorption 12.0%, hardness 5.5%, particles having a particle size of not less than 2.36 mm and not more than 0.98 mm were 0.0% by weight and 6%, respectively. In a rotary mixer (concrete mixer), 94 parts of 0.0% by weight of porous prill nitrate and 6 parts of No. 2 light oil are mixed for 4 minutes at a speed of 60 rotations per minute, and 100 parts of a comparative explosive composition (ANF)
O explosives). (Explosive described in JP-A-12-16891)

Comparative Example 2 85.0 parts of porous prill nitrate and 5 parts of No. 2 light oil as in Comparative Example 1 were mixed at room temperature with a rotary mixer (concrete mixer)
Then, the mixture was mixed at a speed of 60 rotations per minute for 3 minutes, and then 15 parts of sodium carboxymethylcellulose as in Example 3 were mixed in the same manner as in Example 3 to obtain 100 parts of a comparative explosive composition. (Japanese Patent Laid-Open No. 2000-16891
No.)

Performance Test (1) Explosion Speed Test 1 Each of the explosive compositions obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was filled into a steel pipe having an inner diameter of 50 mm in an amount of 600 g, and a 50 g pentlite was used as a booster to initiate an explosion. The explosion speed was measured.

(2) Explosion speed test 2 No. for standard qualification Using the filter paper of No. 2, a paper cylinder having an inner diameter of 50 mm was prepared, and 600 g of each of the explosive compositions obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was poured into this paper cylinder to form a cartridge. This was placed in a steel pipe having an inner diameter of 65 mm, water was poured into the steel pipe and immersed in water. After soaking in water for 2 hours and 6 hours, detonate 50 g of pentrite as a booster,
The explosion speed was measured.

(3) Fluidity test Each of the explosive compositions obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was directly poured into a PVC pipe having an inner diameter of 60 mm and a length of 1 m to observe and evaluate the fluidity. .

Table 1 shows the results of these tests.

Table 1 Example 1 Example 2 Example 3 Comparative Example 1 Explosion velocity test 1 (m / sec) 3270 3280 3250 2950 Explosion velocity test 2 (m / sec) (2 hours in water) 3220 3240 3210 Non-explosion (6 in water) Time) 3180 3190 3170 Non-explosion Flowability Good Good Good Good Comparative Example 2 Explosion speed test 1 (m / sec) 2500 Explosion speed test 2 (m / sec) (2 hours in water) 2450 (6 hours in water) 2320 Good flowability

From Table 1, the explosive composition of Comparative Example 1 (conventional A
It is apparent that the explosive composition of the present invention has a significantly improved explosive speed as compared with (NFO explosive), and can sufficiently maintain the explosive performance even under conditions where water enters from the surroundings. Furthermore, compared to the explosive composition of Comparative Example 2, the detonation speed is significantly improved, the drop in explosion performance is extremely small under conditions where water enters from the surroundings, and the fluidity of the conventional ANF
It is clear that it is equivalent to an O explosive.

[0042]

According to the present invention, an explosive composition having significantly improved power as compared with the conventional ANFO explosive, and having a significantly smaller decrease in explosive performance under immersion conditions than the conventional water-resistant ANFO explosive can be obtained.

Claims (8)

[Claims] 1. An explosive composition comprising a porous prill ammonium nitrate having a bulk specific gravity of 0.50 to 0.75, a fuel oil and a thickening stabilizer. 2. The explosive composition according to claim 1, wherein the particle diameter of the thickening stabilizer is 0.01 to 3 mm. 3. The explosive composition according to claim 1, wherein the content of the thickening stabilizer is 2.0 to 20.0% by weight of the whole explosive composition. 4. The explosive composition according to claim 1, wherein the porous prill ammonium nitrate has an oil absorption of 5.0 to 24.0% and a hardness of 0.1 to 10.0. 5. The total porous prilled ammonium nitrate having a particle size of not less than 2.36 mm and not more than 0.98 mm is contained in a proportion of not less than 0.5% by weight and not more than 1.0% by weight, respectively. The explosive composition according to any one of claims 1 to 4. 6. The explosive composition according to any one of claims 1 to 5, wherein the porous prill ammonium nitrate is a mixture of porous prill ammonium nitrate containing fine hollow particles in a substrate or a pulverized product thereof. 7. A 20% by weight aqueous solution of a thickening stabilizer at 20 ° C.
The explosive composition according to any one of claims 1 to 6, wherein the pressure is 20 to 10000 mPa · s. 8. The explosive composition according to claim 1, wherein the thickening stabilizer is sodium carboxymethylcellulose, sodium polyacrylate, or a mixture thereof.