JP2002047089A - Water resistant granular explosive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an explosive composition having water resistance, excellent in handleability like a conventional ANFO(ammonium nitrate/fuel oil) explosive, and having the same explosive performance as the conventional one. SOLUTION: The porous prill of ammonium nitrate including fine hollow particles in its substrate is coated with a polymer which is in a liquid or emulsified state by heat melting during a coating process and is solidified after coating, and is mixed with a fuel oil, if necessary to obtain the objective water resistant granular explosive composition.

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 a water-resistant granular explosive composition which is widely used in industrial blasting operations such as crushed stone, mining, coal mining, and excavation, and can be used by directly loading it into a perforation or the like.

[0002]

2. Description of the Related Art Dynamite, hydrous explosives, nitrate explosives, and nitrate oil explosives (hereinafter referred to as ANFO explosives) are well known as explosives used for industrial blasting operations and the like.
Of these explosives, ANFO explosives are relatively easy to manufacture and are less expensive than other industrial explosives.
It is well known as a highly safe explosive. Also, AN
The FO explosive is composed of a fluid granular material, and has a feature that it can be directly poured into a perforation or loaded by a loading machine such as a loader. For these reasons, ANFO explosives are very widely used.

[0003]

The main component of the ANFO explosive is porous granular (hereinafter, referred to as porous prill) ammonium nitrate (hereinafter, referred to as ammonium nitrate), and often accounts for 90% by weight or more of the entire explosive. The ANFO explosive is an explosive in which a liquid fuel component such as light oil is mixed with the porous prill nitrate. On the other hand, nitric acid is about 12
0 g and about 950 g at 100 ° C., and it is very soluble in water.

[0004] Therefore, in the case of ANFO explosives, when water is present in the blast hole, groundwater infiltrates, or when water penetrates into the hole in rainy weather, ammonium nitrate easily dissolves in the hole. Explosive properties may be lost due to light oil separation. Therefore, under such conditions, a package explosive such as a 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. Often done. However, in the former case, the explosive used is more expensive than the ANFO explosive, and the blasting cost increases. The latter case not only loses the advantage of the ANFO explosive that it can be easily loaded in bulk, but also creates a gap between the packaged explosive and the perforated wall, and the ANFO explosive in the perforated hole.
Compared to the case of loading explosives directly, a sufficient blasting effect cannot be obtained. In addition, the ANFO explosive packaged in such a polytube is damaged by the sharp stones of the perforated wall when charging into the perforation, and as a result, water penetrates into the inside of the package, and the ANFO explosive absorbs moisture. Explosion performance may be lost. In order to solve the above-mentioned problems, explosives obtained by adding a water-absorbing agent to ANFO explosives have been developed and put into practical use (JP-A-2000-16891). However, when using them, it is necessary to once remove water from the inside of the perforation by using a drainage pump or the like, which increases the number of steps in the charging operation. An explosive composition that maintains water resistance by coating a granular explosive containing porous prill nitrate and fuel oil using a solid polymer has been developed.
We have not yet reached the equivalent of an NFO explosive.

[0005]

SUMMARY OF THE INVENTION The present inventors have determined that water and infiltration present in the perforations can be used without impairing the advantages of the ANFO explosive, which can be used in bulk, has fluidity, and is easy to handle. As a result of intensive studies to develop a granular explosive with excellent water resistance that can be used without removing water, it is in the form of a liquid or emulsion by heating and melting during the coating process as porous prill nitrate. ,
And coated with a polymer that solidifies after coating,
A particulate explosive composition containing porous prilled ammonium nitrate containing fine hollow particles (optionally containing fuel oil) is disclosed in ANF
The conventional A
The present invention has been found to have excellent water resistance as compared to NFO explosives and to exhibit the same explosive performance, and thus has completed the present invention.

That is, the present invention includes (1) a water-resistant granular explosive composition comprising micro hollow particles and containing porous prill ammonium nitrate coated with a solid polymer, and (2) micro hollow particles. And a water-resistant granular explosive composition containing porous prill ammonium nitrate coated with a solid polymer and a fuel oil, and (3) an oil absorption rate of porous prill ammonium nitrate containing fine hollow particles of 5.0 to 20.0%. Yes and hardness 1
The bulk specific gravity of the water-resistant granular explosive composition according to (1) or (2), which is 0.0% or less, and (4) the bulk specific gravity of the porous prill ammonium nitrate including the fine hollow particles, is 0.55 to 0.7.
8. The water-resistant granular explosive composition according to any one of (1) to (3), wherein (5) the particle size of the porous prill ammonium nitrate containing the fine hollow particles is 2.36 mm or more and 0.98 mm. The present invention relates to the water-resistant granular explosive composition according to any one of (1) to (4), wherein the following are 1.0% by weight or more and 1.0% by weight or less, respectively.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the explosive composition of the present invention, the fine hollow particles are contained in an amount of 1.0 × 10 ^{−6 to} 10.0% by weight, preferably 1.0 × 10 ^{−3 to} 10.0% by weight based on the amount of porous prill nitrate. Is used. These fine hollow particles are mainly used as a specific gravity adjusting agent and the like, and specific examples of the fine hollow particles that can be used include:
There are natural or synthetic porous materials such as resin microballoons, glass balloons, hollow metal particles, and shirasu balloons, and these are used alone or in combination of two or more. In the present invention, resin microballoons are preferred among the above. Porous prill ammonium containing fine hollow particles used in the explosive composition of the present invention has an oil absorption of 5.0 to 20.0%,
Preferably, it has a hardness of 7.0 to 18.0% and a hardness of 10.0% or less, preferably 5.0% or less. The explosive composition of the present invention has a bulk specific gravity of 0.55 to 0.5.
Porous prill ammonium nitrate containing 78, preferably 0.60 to 0.73, hollow microparticles is used. Furthermore,
Porous prill ammonium containing fine hollow particles used in the explosive composition of the present invention has a particle size of 2.36.
mm and 0.98 mm or less, respectively.
It is preferably 0% by weight or more and 1.0% by weight or less.

[0008] The oil absorption of porous prill nitrate is determined by immersing a fixed amount of sample (porous prill nitrate) in light oil for a certain period of time, performing suction filtration, and calculating the adsorption amount of light oil from the weight difference before and after the test. Is measured by Specifically, 50 g of porous prill nitrate is placed in a glass filter (11G-1) having a diameter of 40 mm and a depth of 50 mm, weighed with a direct balance on an upper plate, 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 fine rod to achieve mixed contact between porous prill nitrate and light oil. 5
After standing for 1 minute, open the external cock attached to the glass filter and let light oil flow naturally for 2 minutes. Subsequently, after suctioning with a vacuum pump for 5 minutes (flow rate: about 30 l / min), the glass filter in which the porous prill nitrate of the sample to which light oil has been adsorbed 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 ratio (%) of the light oil adsorption (g) to 50 g of the original sample, porous prill nitrate, is indicated as the oil absorption (%). The calculation formula is as shown in the following formula (1). Oil absorption rate (%) = light oil adsorption (g) / sample 50 (g) x 100 (1)

The hardness of porous prill nitrate is measured by mechanically pulverizing a certain amount of porous prill nitrate under a predetermined condition using a hardness measuring device and measuring the amount of 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 a sample (porous prill nitrate) from which powder has been removed by a 35 mesh sieve is dropped from a funnel through a sample injection tube into a flow pipe, and is injected with compressed air (4 kg / cm ² ) flowing from an inlet into the porous prill ammonium nitrate. Through the flow pipe to collide with the inner wall of the pulverizing pipe to powder the porous prill nitrate. Porous prill nitrate 35mes after shipping
h, and the amount (N) of +35 mesh is weighed and expressed as a ratio (%) of the powdered amount to the original 100 g of porous prill nitrate. The calculation formula is as shown in the following formula (2). Hardness (%) = 100 (g) −N (g) (2)

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 was dropped from a certain height into a cylindrical cup placed on a support base using a funnel having a damper at a lower part supported by a support rod, and was raised on the cup. After removing the porous prill nitrate, it is measured by weighing the porous prill nitrate in the cup. Specifically, the upper end diameter is 90 mm, and the lower end diameter is 15
mm, a funnel with a height of 115 mm, the distance between the lower end of the funnel and the upper end of the cup with a depth of 80 mm on the support base and a volume of 100 cm ³ is 45 mm, 100 g of porous prill nitrate is put in the funnel, and the damper is placed. Slide to drop the porous prill nitrate sample into the glass. Carefully take care not to vibrate, and use a spatula to remove the porous prilled nitric acid raised on the glass so that it is level with the top of the glass. The porous prill nitrate adhered to the outside of the cup is removed, and the weight of the porous prill nitrate in the cup is weighed by a direct reading balance. After completing the above measurement, the bulk specific gravity is calculated by the following equation (3). Bulk specific gravity = sample weight (g) / 100 (cm ³ ) (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 weight of the residue on the sieve net for each sieve.

As the solid polymer used as a coating agent in the explosive composition of the present invention, any substance can be used as long as it forms a film on the surface of porous prill nitrate and has water resistance. Two or more types are used in combination. Further, the solid polymer used in the explosive composition of the present invention is preferably a solid polymer which is in the form of a molten liquid or an emulsion during the coating step, and which solidifies after coating. Specific examples of solid polymers that can be used include fluoroolefin resins, aromatic vinyl resins, polyvinyl acetate resins, styrene / butadiene resins, acrylic resins, polyurethane resins, polyester resins, epoxy ester resins, polyethylene resins, and the like. Resins, styrene / butadiene copolymer rubber, butadiene rubber, acrylonitrile / butadiene copolymer rubber,
Rubbers such as acrylic rubber are exemplified. In the present invention, among these, acrylic resins, styrene / butadiene resins, polyurethane resins, styrene / butadiene copolymer rubbers, and acrylonitrile / butadiene copolymer rubbers are preferred.

The amount of the solid polymer used in the explosive composition of the present invention is 2.5 to 50.0% by weight, preferably 7 to 5% by weight, based on the amount of porous prill nitrate containing fine hollow particles.
４40.0% by weight.

In the explosive composition of the present invention, a fuel oil is used if necessary. As the fuel oil, any flammable organic substance that is liquid at the time of mixing can be used. Specific examples of preferred fuel oil include light oil, mineral oil such as kerosene, soybean oil, rapeseed oil, castor oil and the like. Vegetable oil, tallow,
Animal oils such as squalene; In addition, if necessary, alcohols such as methyl alcohol and ethyl alcohol, waxes such as paraffin wax and microcrystalline wax, and nitro compounds such as dinitrotoluene and dinitroxylene can be used alone or as a mixture 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.

In the explosive composition of the present invention, the amount of the fuel oil optionally used is usually 2.5 to 25.0% by weight, preferably 4.0 to 10.0% by weight of the whole explosive composition.
% By weight.

The explosive composition of the present invention can be subjected to measures for preventing static electricity generation, if necessary. For example, water-soluble and oil-soluble antistatic agents (JP-A-55-51794, JP-A-11-147784, JP-A-11-278974)
), Additives such as starches (JP-A-10-291883) and fatty acid amides.

The explosive composition of the present invention is prepared by mixing and mixing porous prill ammonium nitrate containing fine hollow particles in a substrate and a solid polymer in a heated molten state or as an emulsion by a mixer such as a kneader or a high-speed mixer. By doing so, porous prill nitrate coated with the solid polymer is obtained.

The explosive composition of the present invention containing fuel oil can be obtained by stirring and mixing porous prill nitrate containing fine hollow particles and fuel oil with a mixer such as a kneader or a high-speed mixer as described above.

The explosive composition of the present invention, which further contains other additives, comprises a porous prill nitrate containing fine hollow particles in a mixer such as a kneader or a high-speed mixer and coated with a solid polymer; The explosive composition of the present invention can be obtained by stirring and mixing the same. It should be noted that other mixers other than those described above can also be used as long as they have stirring and mixing functions.

The explosive composition of the present invention can be used in bulk and has fluidity, like the conventional ANFO explosive.
It is excellent in handleability and can be used without removing water present in the perforation and intruding water. Further, by using porous prill nitrate containing fine hollow particles in a substrate, the explosion performance is improved while maintaining water resistance.

[0022]

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 following examples, parts show parts by weight.

Example 1 A resin microballoon containing 0.03% by weight, an oil absorption of about 11.7%, a hardness of 1.0%, a bulk specific gravity of 0.76,
A sigma blade heated to 90 ° C. was heated to 90 ° C. with 70.5 parts of porous prill nitrate having a particle diameter of 2.36 mm or more and 0.98 mm or less, 3.6% by weight and 0.3% by weight, respectively. 100 in a horizontal kneader container per minute
While stirring at a rotating speed, 29.5 parts of ethylene homopolymer (manufactured by Toyo Petrolite Co., Ltd.) melted at 100 ° C. was added to obtain 100 parts of the explosive composition of the present invention.

Example 2 Resin microballoons containing 0.10% by weight, an oil absorption of about 12.5%, a hardness of 3.0%, a bulk specific gravity of 0.68,
71.4 parts of porous prill nitrate having a particle size of 2.36 mm or more and 0.98 mm or less of 53.3% by weight and 0.0% by weight, respectively, were placed in a container of a high-speed mixer heated to 50 ° C. While stirring at a speed of 150 revolutions per minute, 48.6 parts of a latex of a styrene-butadiene copolymer rubber having a solid component of 50.0% by weight was added, and the explosive composition 95.7 of the present invention was added. Got a part.

Example 3 The same porous prill nitrate (72.3 parts) as in Example 1 was added to 90
Into a high-speed mixer vessel heated to
3. Ethoxylated alcohol (manufactured by Toyo Petrolite Co., Ltd.) melted at 100 ° C. while stirring at a speed of 00 rotations.
6 parts were added to obtain a granular explosive composition. Polyurethane melted at 130 ° C (Nihon Polyurethane Industry Co., Ltd.)
23.1 parts) to obtain 100 parts of the explosive composition of the present invention.

Example 4 A resin microballoon containing 0.25% by weight, an oil absorption of about 12.4%, a hardness of 3.6%, a bulk specific gravity of 0.63,
Porous prill ammonium nitrate (EXPAN100: Sasol C) having a particle size of not less than 2.36 mm and not more than 0.98 mm is 30.4% by weight and 0.0% by weight, respectively.
chemical IndustriesLimited
67.1 parts was placed in a container of a horizontal kneader equipped with a sigma wing heated to 90 ° C., and stirred at a speed of 80 revolutions per minute, and melted at 100 ° C. with microcrystalline wax (Toyo Petrolite (Toyo Petrolite) 4.3 parts) was added to obtain a granular explosive composition. This was put into a container of a high-speed mixer heated to 50 ° C., and 28.6 parts of an acrylic emulsion (manufactured by JSR Corporation) having a solid content of 50.0% by weight was stirred while stirring at a speed of 200 revolutions per minute. Was added to obtain 85.7 parts of the explosive composition of the present invention.

Comparative Example 1 Porous prill nitrate (bulk specific gravity 0.78, particle size 2.36)
mm and 0.98 mm or less respectively have a content of 0.0% by weight and 6.0% by weight, an oil absorption of 12.0%,
94.0 parts of No. 2 light oil at room temperature were mixed at room temperature in the same manner as in Example 1 to 94.0 parts of hardness (5.5%) to obtain 100 parts of comparative granular explosive (specific gravity 0.87). (JP-A-8-2
Explosives described in 6877)

Evaluation Test (1) Fluidity and Water Resistance Test Each of the explosive compositions obtained in Examples 1 to 4 and Comparative Example 1 was
3 pieces each in a transparent acrylic tube with an inner diameter of 50 mm filled with water.
The water resistance was evaluated by pouring 00 g, evaluating the fluidity, and observing the state of immersion and floating.

(2) Explosive speed test 1 Each of the explosive compositions obtained in Examples 1 to 4 and Comparative Example 1 was
Fill 300g each into 50mm inside diameter steel pipe, 50g
Was used as a booster to measure the explosion velocity.

(3) Explosion speed test 2 Each of the explosive compositions obtained in Examples 1 to 4 and Comparative Example 1 was
Each 300 g was poured into a steel pipe having an inner diameter of 50 mm into which water was poured, and immersed in water for 1 hour. After that, 50 g of a water-containing explosive (described above) was used as a booster, and the explosion speed was measured.

The results are shown in Table 1.

Table 1 Table 1 Evaluation Test Results Example 1 Example 2 Example 3 Flowability Good Good Good Water Resistance (after 1 hour) About 14% of the entire explosive composition of the entire explosive composition Approximately 12% is floating Approximately 15% is floating Explosion speed test 1 (m / sec) 2940 3100 3010 Explosion speed test 2 (m / sec) 2620 2920 2730 Example 4 Comparative Example 1 Flowability Good Good Waterproof (after 1 hour) Approximately 10% of the entire explosive composition is suspended 100% is suspended / dissolved Explosive speed test 1 (m / sec) 3210 3350 Explosive speed test 2 (m / sec) 2850 Non-explosion

From the above results, it is clear that the explosive composition of the present invention has the same fluidity as the conventional ANFO explosive (Comparative Example 1), and can be directly poured and charged. Further, it has superior water resistance as compared with the explosive of Comparative Example 1, and has almost the same explosive performance. When the explosive of Comparative Example 1 becomes non-explosive when detonated in that state after being further submerged for one hour, it is clear that the explosive composition of the present invention maintains sufficient explosive performance. is there.

[0034]

According to the present invention, an explosive composition having the same handling properties as that of the conventional ANFO explosive and having sufficient water resistance and explosive performance in water can be obtained.

Claims (5)

[Claims] 1. A water-resistant granular explosive composition comprising fine hollow particles and containing porous prill ammonium nitrate coated with a solid polymer. 2. A water-resistant granular explosive composition comprising fine hollow particles and coated with a solid polymer coated with porous prill ammonium nitrate and a fuel oil. 3. The method according to claim 1, wherein the oil absorption of the porous prill ammonium nitrate containing the fine hollow particles is 5.0 to 20.0% and the hardness is 10.0% or less. Water resistant granular explosive composition 4. The water-resistant granular explosive composition according to any one of claims 1 to 3, wherein the bulk specific gravity of the porous prill ammonium nitrate containing the fine hollow particles is 0.55 to 0.78. 5. The porous prill ammonium nitrate containing fine hollow particles has a particle size of not less than 2.36 mm and 0.9.
The water-resistant granular explosive composition according to any one of claims 1 to 4, wherein the composition having a size of 8 mm or less is 1.0% by weight or more and 1.0% by weight or less, respectively.