JP2002338383A - Explosive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop an explosive composition which exhibits high explosion performance even under conditions of a relative small boring diameter like blasting in an underground space, such on a tunnel site or in a pit or mine and is capable of suppressing the amount of the ammonia to be produced in spite of contact with basic materials. SOLUTION: This explosion composition consists of a porous prill ammonium nitrate having a bulk specific gravity 0.50 to 0.75, fuel oil and a solid organic acid of an average grain size 0.01 to 3.0 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to explosive compositions. More specifically, the present invention relates to an explosive composition that can be widely used for industrial blasting applications such as quarrying, mining, coal mining, and digging.

[0002]

2. Description of the Related Art As explosives used in industrial blasting operations, there are well-known explosives such as ammonium nitrate explosives (hereinafter referred to as ANFO explosives), hydrous explosives, dynamite, and ammonium nitrate explosives.
Among these explosives, ANFO explosives are granular ammonium nitrate having pores (hereinafter referred to as porous prill nitrate).
Is a granular explosive mixed with light oil, and the raw material is inexpensive.
Due to its simple manufacturing method, it is marketed as an inexpensive explosive. Further, the ANFO explosive is an explosive that cannot be detonated with a single detonator, and is known as an insensitive and highly safe explosive as compared with other industrial explosives. In addition, ANFO
Since the explosive can be supplied in the form of granules, the explosive can be mechanically loaded into the perforation by using a loading machine or can be directly poured into the vertical hole, so that there is an advantage that the charging operation is simple. For these reasons, ANFO explosives are widely used.

[0003]

Since the ANFO explosive is a safe explosive as described above, it is only allowed to be packaged in double bags in Japan, and it has been approved in foreign countries to manufacture it at the site of use. In some countries. Further, as described above, since the charging operation is safe and inexpensive and the charging operation is simple, it has been used for blasting in a closed space such as a tunnel site or a mine pit.

[0004] However, since the ANFO explosive is generally used in bulk without being packaged like dynamite and hydrous explosives, the components of the explosive are directly exposed to the surrounding environment, and the ammonium nitrate contained in the ANFO explosive is reduced. May decompose. In particular, blasting sites such as tunnel excavation sites and underground mines use mortar (of cement) or concrete as a reinforcing agent for rock after blasting. On contact, toxic ammonia gas may be generated in the human body. When ammonia gas is generated, its toxicity and irritating odor make it difficult to continue work in the surroundings.

[0005] Furthermore, in the case of blasting in an underground space such as a tunnel excavation site or an underground mine, the drilling diameter for charging an explosive is relatively smaller than that in the case of blasting on the ground. The explosive velocity change with the diameter of the explosive is larger than that of the industrial explosives of the prior art.
There is a possibility that the explosive performance of the O explosive may not be fully utilized.

[0006]

Means for Solving the Problems The present inventors have developed an ANFO.
Granular explosives that suppress the generation of ammonia gas during explosive operations and exhibit high explosive behavior even in small pore sizes, making full use of the advantages of explosives such as fluidity during explosive operations and the simplicity of the manufacturing process As a result of intensive research to develop, the explosive composition consisting of a specific porous prill nitrate, fuel oil, and organic acid has the same fluidity as conventional ANFO explosives,
Along with suppressing the generation of ammonia gas,
Compared with the conventional ANFO explosive, it has been found that the power is remarkably improved even in a small hole diameter, and the present invention has been completed.

That is, according to the present invention, (1) the bulk specific gravity is 0.5
An explosive composition comprising: 0 to 0.75 porous prill ammonium nitrate; a fuel oil; and a solid organic acid having an average particle size of 0.01 to 3.0 mm. The explosive composition according to (1), which is 0.1 to 20% by weight of the entire explosive, (3) Porous prill ammonium nitrate has an oil absorption of 5.0 to 24.0% by weight and a hardness of 0.1 to 10%. The explosive composition according to any one of (1) to (2), which is 0%, and (4) the porous prill ammonium nitrate has a particle size of not less than 2.36 mm and 0.
The explosive composition according to any one of (1) to (3), wherein 98 mm or less of the explosive composition is 0.5% by weight or more and 1.0% by weight or less, respectively. The explosive composition according to any one of (1) to (4), which is a mixture with porous prill ammonium nitrate containing fine hollow particles therein, or a pulverized product thereof, and (6) the organic acid is a dicarboxylic acid. (1) The explosive composition according to (5), and (7) the explosive composition according to (1) to (6) to which metal powder is added as an additional fuel.

[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.
Porous prill nitrate which is between 8 and 0.70 is used.
Porous prill nitrate is 65-65% of the total explosive composition.
It is used in an amount of 96% by weight, preferably 75 to 95% by weight. Further, the porous prill nitrate used in the explosive composition of the present invention has an oil absorption of 5.0 to 24.0% by weight, preferably 7 to 20% by weight, and a hardness of 0.1 to 10% by weight.
It is preferably 0% by weight, preferably 0.1 to 5.0% by weight. Further, as the porous prill ammonium nitrate used in the explosive composition of the present invention, those having a particle diameter of not less than 2.36 mm and not more than 0.98 mm are not less than 0.5% by weight and not more than 1.0% by weight, respectively. Is preferred. 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 ^{−3 to} 10.0% by weight, preferably 0.03 to 5.0% by weight. Porous prill ammonium 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, the porous prill ammonium nitrate having the above-mentioned particle size and the pulverized product thereof can be mixed at an arbitrary ratio. Preferably, the mixing ratio of the pulverized product to the porous prill nitrate is 20 to 80% by weight.

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 table 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,
100 g of the sample porous prill nitrate is put into the funnel, and the damper is slid to drop the sample porous prill nitrate into the cup. 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 rate of ammonium nitrate is measured by immersing a fixed amount of sample nitric acid in light oil for a certain period of time, then 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 mm in diameter and 50 mm in depth.
It is put in a glass filter (11G-1) of 1 mm, weighed with an upper plate direct reading 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, after suctioning with a vacuum pump for 5 minutes (flow rate: about 30 l / min), the glass filter containing the sample ammonium adsorbed with light oil is weighed with an upper plate direct balance. Here, the increased amount is the absorbed amount of light oil. After the above measurement is completed, the original sample
The ratio (%) of the light oil adsorption (g) to g 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 (12 mm inner diameter,
(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. Specific 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 2.5 to 25% by weight of the entire explosive composition,
Preferably it is in the range of 4 to 10% by weight.

The solid organic acid used in the explosive composition of the present invention may be any organic acid that can decompose porous prill nitrate and suppress the generation of ammonia gas. Considering the use of a machine such as a loading machine, a weak acid is preferred. Also,
In consideration of the oxygen balance of the entire explosive composition, the organic acid preferably has a small number of carbon atoms, and preferably has 1 to 10 carbon atoms.
Specific examples of organic acids that can be used include dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, citric acid, malic acid, tartaric acid, and glucaric acid. As the organic acid used in the explosive of the present invention, all of the above can be used, but in consideration of economy, inexpensive ones are preferable, and dicarboxylic acids, particularly fumaric acid, citric acid, malic acid, and tartaric acid are preferable. .

The organic acid used in the explosive composition of the present invention has a problem that if its particle size is too large, it does not show a sufficient effect, and if it is too small, it becomes difficult to handle.
0.01-3.0 mm, preferably 0.05-1.0 m
An average particle diameter of m is used.

If the amount of the organic acid used in the explosive composition of the present invention is too small, no effect is exhibited, and if it is too large, the performance of the explosive deteriorates and the cost of the explosive composition increases. Therefore, it is preferably used in the range of 0.1 to 20% by weight, more preferably 1.0 to 15% by weight of the whole explosive composition.

The explosive composition of the present invention may, if necessary,
Measures can be taken to prevent static electricity. For example, a water-soluble or oil-soluble antistatic agent (JP-A-55-51794)
Surfactants known as JP-A No. 11-147784 and starches (JP-A-10-291883).
) And fatty acid amides (JP-A-11-322481).

As is well known to those skilled in the art, the explosive composition of the present invention may optionally contain an oxidizing agent other than porous prill nitrate,
It is possible to add additional powdered fuels such as, for example, potassium nitrate and perchlorate, as well as wood flour, aluminum flour or other additives.

In addition, an oxidizing agent other than porous prill ammonium nitrate such as powdery ammonium nitrate, sodium nitrate and ammonium perchlorate can be added.

The explosive composition of the present invention is produced by uniformly mixing the above-mentioned porous prill nitrate, fuel oil and organic acid with a mixer such as a kneader or a rotary mixer. At this time, the fuel oil may be added after mixing the porous prill nitrate and the organic acid, or the organic acid may be mixed after mixing the fuel oil and the porous prill nitrate. 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. Further, if necessary, it is also possible to perform stirring and mixing while applying heat.

The explosive composition of the present invention has excellent handling properties similar to conventional ANFO explosives, and can be used with conventional ANFO explosives even when blasting in small holes in underground spaces such as tunnel sites and underground mines. In addition to showing significantly higher explosive performance, even if basic substances are present in the surroundings, the organic acid in the explosive composition suppresses the generation of ammonia gas and does not make the working environment around explosive handling uncomfortable Has features.

[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” indicates “parts by weight”.

Example 1 3.6% by weight and 0.7% by weight of oil having a bulk specific gravity of 0.73, an oil absorption of 11.7% by weight, a hardness of 1.0% by weight and a particle size of not less than 2.36 mm and not more than 0.98 mm, respectively. 0.0 parts by weight, 85 parts of porous prill nitrate containing 0.05% by weight of fine hollow particles, and 5 parts of No. 2 light oil were mixed at room temperature with a rotary mixer (concrete mixer) at 60 rotations per minute for 2 minutes, Thereafter, malic acid 5 in the form of fine particles having an average particle size of 0.3 mm
Were mixed at the same rotation speed for 1 minute to obtain 100 parts of the explosive composition of the present invention.

EXAMPLE 2 0.7% by weight and 0.6% by weight of oil having a bulk specific gravity of 0.67, an oil absorption of 17.3% by weight, a hardness of 6.4% by weight and a particle size of not less than 2.36 mm and not more than 0.98 mm, respectively. In a horizontal kneader equipped with sigma wings at room temperature, 91 parts of 0.0% by weight of porous prill nitrate and 10 parts of finely divided fumaric acid having an average particle size of 0.2 mm are added at room temperature, and 6 parts of No. 2 light oil is further added. 8 per minute
The mixture was mixed at 0 rotation for 5 minutes to obtain 100 parts of the explosive composition of the present invention.

Example 3 87 parts of the same porous prill ammonium nitrate as in Example 1 and 10 parts of microparticulate malic acid having an average particle diameter of 0.3 mm were placed in a rotary mixer (concrete mixer) at room temperature, and 8 parts per minute.
While rotating at 0 speed, 3 parts of No. 2 light oil was added and mixed for 5 minutes to obtain 100 parts of the explosive composition of the present invention.

Comparative Example 1 Those having a bulk specific gravity of 0.78, an oil absorption of 12.0%, a hardness of 5.5%, and a particle size of not less than 2.36 mm and not more than 0.98 mm were 0.0% by weight and 6.0%, respectively. 94 parts by weight of porous prill nitrate and 6 parts of No. 2 light oil are put into a rotary mixer (concrete mixer) at room temperature, mixed at a speed of 80 rotations per minute for 5 minutes, and 100 parts of explosive composition for comparison (ANF)
O explosives). (Explosive described in JP-A-11-79878)

Performance Test (1) Measurement of Amount of Ammonia Gas Generated 100 g of each of the explosive compositions obtained in Examples 1 to 3 and Comparative Example 1 were filled into a closed glass container having a content of 1 liter, and each container was charged into each container. After adding 100 g of cement and sealing, 1
Shake the container vigorously for minutes to mix. After 10 minutes, the ammonia gas generated in the container was adsorbed to 100 ml of distilled water, titrated with 1N hydrochloric acid using methyl orange as an indicator, and the amount of ammonia gas generated was quantitatively compared.

(2) Explosion speed test 1 Each of the explosive compositions obtained in Examples 1 to 3 and Comparative example 1 was filled into a steel tube having an inner diameter of 50 mm in an amount of 600 g, and the explosive speed was measured using a 50 g pentolite as a booster. .

(3) Explosion Speed Test 2 Each of the explosive compositions obtained in Examples 1 to 3 and Comparative Example 1 was filled in a steel tube having an inner diameter of 34 mm, and the explosion was measured using a 20 g pentrite as a booster, and the explosion speed was measured.

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

Table 1 shows the results of these tests.

Table 1 Example 1 Example 2 Example 3 Comparative Example 1 Explosion speed 1 3310 3290 3280 3150 (m / sec) Explosion speed 2 3120 3110 3110 2850 (m / sec) Ammonia generation amount 3.2 1.0 0.0 5 50 (mol / l) Flowability Good Good Good Good

Table 1 shows that, compared to the explosive composition of Comparative Example 1,
The explosive composition of the present invention has fluidity similar to that of a conventional ANFO explosive, significantly reduces the amount of ammonia gas generated, and has a significantly improved power even in a small hole diameter compared to a conventional ANFO explosive. It is clear that you are.

[0042]

EFFECTS OF THE INVENTION As with the conventional ANFO explosive, the conventional ANF has excellent handleability and can be used under the condition that the pore size is relatively small.
An explosive composition was obtained, in which the power was significantly improved as compared with the O explosive, and the amount of generated ammonia was suppressed even when contacted with a basic substance.

Claims (7)

[Claims] 1. A porous prill ammonium nitrate having a bulk specific gravity of 0.50 to 0.75, a fuel oil and an average particle diameter of 0.01
An explosive composition comprising a solid organic acid having a size of about 3.0 mm. 2. The explosive composition according to claim 1, wherein the content of the organic acid is 0.1 to 20% by weight of the whole explosive. 3. Porous prill ammonium nitrate has an oil absorption of 5.0 to 24.0% by weight and a hardness of 0.1 to 10.
The explosive composition according to any one of claims 1 to 2, which is 0%. 4. The porous prill ammonium nitrate having a particle size of not less than 2.36 mm and not more than 0.98 mm has a particle size of not less than 0.5% by weight and not more than 1.0% by weight, respectively. Explosive composition according to claim 1 5. 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.
An explosive composition according to any one of claims 1 to 4. 6. The explosive composition according to claim 1, wherein the organic acid is a dicarboxylic acid. 7. The explosive composition according to claim 1, wherein a metal powder is added as an additional fuel.