JP2001181081A - Particle state explosive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a particle state explosive hardly generating the separation of its components by transportation, or the like, not causing deterioration of its performance and handling property with time, generating the same after gas components with those of the conventional ANFO explosive, after its blast and further capable of adjusting its specific gravity optionally, i.e., capable of controlling its exploding speed optionally. SOLUTION: This particle state explosive contains a porous prill ammonium nitrate, a fuel oil and an inorganic hollow material having 0.10-0.30 bulk specific gravity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to explosives. More specifically, the present invention relates to a granular explosive used for blasting operations such as quarrying, mining, tunneling, etc., and particularly for controlled blasting to minimize rock damage.

[0002]

2. Description of the Related Art It is well known that controlled blasting is performed by using an explosive in a small-diameter resin cylinder or an explosive in a plastic bag in a large perforation in order to obtain a decoupling effect. If there is no water in the hole, a granular explosive obtained by mixing styrofoam with an ammonium nitrate explosive (hereinafter referred to as ANFO explosive) may be used because it is inexpensive and easy to load.

[0003]

When control blasting is performed,
It is most efficient and economical to load a granular explosive in a case where there is no water in the hole, by blowing it with compressed air in a horizontal hole, and by flowing it in a free flow in a vertical hole.

However, granular explosives obtained by mixing styrofoam with ANFO explosives are: (1) Since the specific gravity of styrofoam is extremely lower than that of porous prill ammonium nitrate (hereinafter referred to as "porous prill nitrate"), the components are not transported or charged. Separation (porous prill nitrate and styrofoam are locally unevenly distributed) is likely to occur, resulting in uneven crushing or detonation interruption. (2) When a certain time has passed after the production, the styrofoam is attacked by the fuel oil in the ANFO explosive, and becomes viscous, sticking the whole explosive and losing fluidity.
(3) After blasting, there is a problem that cyan is generated in gas from styrofoam and ammonium nitrate, and the fact is that it is not widely used.

[0005]

In order to solve the above-mentioned problems, if porous prill nitrate, a fuel substance and an inorganic hollow body are mixed to form a granular explosive, separation of components is extremely unlikely to occur. Without deterioration and loss of liquidity,
Further, it is known that cyan is not generated in the post-gas (Japanese Patent Laid-Open No. Hei 8-26877). The present inventors have assiduously studied and found that even if an inorganic hollow body having a smaller bulk specific gravity is mixed and used, component separation hardly occurs and an explosive with more stable performance can be obtained, leading to the present invention. Things.

That is, the present invention relates to (1) porous prill ammonium nitrate, a fuel substance and a bulk specific gravity of 0.10 to 0.3.
A granular explosive comprising an inorganic hollow body having a particle diameter of 0, (2) an inorganic hollow body having an average particle size of 0.2 to 4.5.
mm, the granular explosive according to (1).

Hereinafter, the present invention will be described in detail. Porous prill nitrate used as an essential component of the granular explosive of the present invention has a bulk specific gravity of 0.60 to 0.80, preferably 0.65 to 0.75, and an oil absorption of 5 to 24%, preferably 10 to 10. -22%, hardness 0.1-20.0%, preferably 0.1-10.0%, average particle size 0.5-3.0m
m, preferably 1.0 to 2.5 mm of porous prill nitrate. In the granular explosive of the present invention, porous prill ammonium nitrate is usually 25 to 90 wt. %, Preferably 5
0 to 80 wt. % Contained in granular explosives.

[0008] 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 of 80 mm on the bottom of the funnel and the support base, volume 100 cm3
Is installed so that the distance from the top of the cup is 45mm,
100 g of porous prill nitrate of the sample is put into the funnel, and the damper is slid to drop the porous prill nitrate of the sample 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 completing the above measurement, the bulk specific gravity is calculated by the following equation (1).

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

[0010] The oil absorption rate of porous prill nitrate is measured by immersing a fixed amount of porous prill nitrate in light oil for a certain period of time, filtering by suction, and observing the adsorption amount of light oil from the weight difference before and after the test. Is done. Specifically, 50 g of porous prill nitrate ammonium as a sample 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 apparatus. 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, the ratio (%) of the light oil adsorption (g) to 50 g of the original sample nitrate is displayed as the oil absorption (%). The calculation formula is as shown in the following formula (2).

[0011] Oil absorption (%) = light oil adsorption (g) / sample 50 (g) x 100 (2)

The oil absorption rate of porous prilled ammonium nitrate is mainly determined by the pore volume and effective diameter distributed inside the grains. For example, if the pore volume is large, the space capable of holding light oil inside the grains is reduced. Since it becomes large, the oil absorption rate becomes large.

The hardness of porous prill nitrate is measured by mechanically pulverizing a fixed amount of a sample of porous prill ammonium nitrate under a predetermined condition using a hardness measuring device, and observing the pulverized amount. 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 m inside diameter)
m, length 52 mm) and a sample pulverizing tube (inner diameter 50 mm, length 315 mm) connected vertically to the flow tube. Sample nitrate 100 with powder removed by 35 mesh sieve
g from the funnel into the flow tube through the sample injection tube,
With the compressed air (4 kg / cm ² ) flowing from the inflow hole, the sample passes through the flow pipe and collides with the inner wall of the pulverizing tube to pulverize the sample nitrate. The sample ammonium nitrate after the flow is sieved with 35 mesh, the amount (N) of +35 mesh is weighed, and is displayed as a ratio (%) of the amount of powder to 100 g of the original sample ammonium nitrate. The calculation formula is as shown in the following formula (3).

Hardness (%) = 100 (g) −N (g) (3)

The average particle size of the porous prill nitrate is measured from a weight distribution of each of the predetermined amounts of porous prill nitrate through various sieves having different sieves. The calculation formula is (4) below
According to the formula.

D = Σ (X × R / 100) (4) where D = average particle size (mm) X = average size of sieve mesh (mm) R = residue weight on sieve mesh (%)

Next, as the fuel oil contained as an essential component in the granular explosive of the present invention, it is preferable to use a fuel oil which is liquid at the time of mixing. Specific examples of usable fuel oils include mineral oils such as light oil and kerosene, vegetable oils such as soybean oil, rapeseed oil and castor oil, and animal oils such as tallow and squalene. In addition, alcohols such as methyl alcohol and ethyl alcohol, paraffin wax,
Waxes such as microcrystalline wax and nitro compounds such as dinitrotoluene and dinitroxylene can be used alone or as a mixture as 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 present invention, the fuel oil is usually contained in the granular
~ 25.0 wt. %, Preferably 3.0 to 15.0 w
t. %.

The inorganic hollow material used as an essential component of the granular explosive of the present invention has a bulk specific gravity of 0.10.
~ 0.30, more preferably 0.20 ~ 0.30. The inorganic hollow body used for the granular explosive of the present invention preferably has an average particle size of 0.2 to 4.5 mm. The inorganic hollow material used in the granular explosive of the present invention may be any component as long as it has the above bulk specific gravity, but from the economical viewpoint, natural balloons such as shirasu balloon and perlite are used. It is preferable to use an inorganic hollow body.

In the granular explosive of the present invention, if the amount of the inorganic hollow material used is small, the crushing effect as an explosive is large, and if the amount is large, the crushing effect is reduced. %, Preferably 15 to 50 wt. %
Contained in granular explosives.

The granular explosive of the present invention can be obtained by simultaneously mixing porous prill nitrate, and, if necessary, heating a liquid fuel oil and an inorganic hollow body, to obtain a granular explosive. And then adding an inorganic hollow body. The average particle size of the granular explosive of the present invention is usually about 0.4 to 4.0 mm because the particle size of the used porous prilled ammonium nitrate and inorganic hollow body is maintained almost as it is.

If necessary, the granular explosive of the present invention may be provided with measures for preventing generation of static electricity. For example, water-soluble and oil-soluble antistatic agents (JP-A-55-51794, JP-A-11-147784, JP-A-11-278974)
), And additives such as starches (JP-A-10-291883) and fatty acid amides (JP-A-11-322481).

The granular explosive of the present invention may further comprise an oxidizing agent other than porous prill nitrate, such as potassium nitrate or perchlorate, or powdered fuel such as wood powder or aluminum powder, or sodium polyacrylate, if necessary. Thickening stabilizers (JP-A-8-295588), and organic acids known as ammonia gas inhibitors (JP-A-11-7).
9878) and other additives such as a water absorbing agent. In the granular explosive of the present invention, additives other than the essential components are appropriately added within a range that does not impair the effects of the present invention.

The granular explosive of the present invention contains, as essential components, porous prill nitrate, fuel oil, and an inorganic hollow body having a bulk specific gravity of 0.10 to 0.30. No characteristic change occurs, and no cyan is generated in the gas after blasting, which is suitable for controlled blasting. Further, the granular explosive of the present invention has a feature that the specific gravity can be adjusted over a wide range and arbitrarily, and the power of the explosive can be arbitrarily controlled.

[0024]

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 Porous prill nitrate (bulk specific gravity 0.76, oil absorption 14%,
Transfer 76.4 parts of 7.0% of hardness (average particle size: 1.43 mm) to a concrete mixer at room temperature, and then use No. 2 light oil at room temperature.
6 parts, 20.0 parts of a shirasu balloon having a bulk specific gravity of 0.18 and an average particle diameter of 1.60 mm were added and mixed at a speed of 80 rotations per minute for 5 minutes to obtain a granular explosive of the present invention (specific gravity of 0.6).
5) was obtained.

Example 2 Porous prill nitrate (bulk specific gravity 0.68, oil absorption 24%,
57.0 parts of hardness 12.0%, average particle size 1.50 mm) and 40.0 parts of a shirasu balloon having a bulk specific gravity of 0.30 and an average particle size of 3.0 mm were transferred to a horizontal kneader equipped with a sigma wing at room temperature. Add 3.0 parts of No. 2 light oil at room temperature and add 10 parts per minute.
The mixture was mixed at 0 speed for 3 minutes to obtain a granular explosive of the present invention (specific gravity 0.56).

Example 3 61.5 parts of porous prill nitrate (the same as in Example 1) was transferred to a horizontal kneader equipped with a sigma wing heated to 90 ° C., and heated to 90 ° C. to form liquid dinitrotoluene.
5 parts were added and mixed at a speed of 80 revolutions per minute for 5 minutes. Thereafter, 30.0 parts of perlite having a bulk specific gravity of 0.30 and an average particle size of 0.5 mm and 20% of dimethyldiallylammonium chloride / acrylamide copolymer were added to this mixture.
0.3 part of an aqueous solution (Kayacryl Resin EC-315: manufactured by Nippon Kayaku Co., Ltd.) was added and mixed at the same rotation speed for 1 minute to obtain a granular explosive of the present invention (specific gravity: 0.69).

Comparative Example 1 Porous prill nitrate (bulk specific gravity 0.78, oil absorption 12.0
%, Hardness 5.5%, average particle size 1.20 mm) 94.0 parts of light oil No. 2 at room temperature was mixed with 94.0 parts in the same manner as in Example 1,
A comparative granular explosive (specific gravity 0.87) was obtained. (Explosive described in JP-A-8-26877)

Comparative Example 2 Porous prill nitrate (bulk specific gravity: 0.69, oil absorption: 23.0)
%, Hardness 11.5%, average particle size 1.50 mm) 91.4
Parts, 6.0 parts of No. 2 light oil at room temperature and average particle size of about 2.0 mm
2.8 parts of styrene foam was mixed in the same manner as in Example 1,
A comparative granular explosive (specific gravity 0.83) was obtained (Japanese Unexamined Patent Application Publication No.
Explosives described in -26877).

(1) Measurement of Explosion Speed 200 g of each of the granular explosives obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was poured into a steel pipe having an inner diameter of 35 mm and a thickness of 3.5 mm, and a 40 g pentlite was used as a booster. It detonated and measured the explosion speed. At the time of the explosion velocity measurement, the presence or absence of cyan in the rear gas was checked using a detector tube. (2) Shaking separation test With respect to Examples 1 to 3 and Comparative Example 2, 1 kg thereof was placed in a 2 liter plastic container, and shaken (Retsch).
(Manufactured by GmbH) and shaking at a shaking intensity of 60 for 1 hour to examine whether or not the components were separated. (3) Time-lapse test (evaluation of fluidity and measurement of explosion velocity) After storing the granular explosives of Examples 1 to 3 and Comparative Example 2 for 3 months, they were taken out and evaluated for the presence or absence of fluidity, in the same manner as in (1). The explosion velocity was measured.

Table 1 shows the test results.

Table 1 Performance test Example 1 Example 2 Example 3 Explosion velocity (m / sec) 2200 1650 1860 Cyan Not detected Not detected Not detected Shaking separation None None None Over time: Fluid Fluid Fluid Fluid Explosion speed (m / sec) 2180 1680 1850 Comparative example 1 Comparative example 2 Explosion speed (m / sec) 2950 1720 Cyan component-detection Shaking separation-Styrofoam separated at the top Time: fluidity Styrofoam sticks No fluidity Explosion speed (m / sec) 2930 1330

It is known that the low blast speed is proportional to the controlled blasting effect. Comparing the blast speeds of Examples 1 to 3 with Comparative Example 1, the granular explosive of the Example is an explosive suitable for controlled blasting. I understand. In addition, although the explosion speed of Comparative Example 2 was sufficiently low, cyan components were detected, component separation in the shaking separation test, and deterioration in handleability and performance over time were observed, and the original characteristics of the ANFO explosive were impaired. I understand.

[0034]

The specific gravity can be arbitrarily adjusted, that is, the explosion speed can be arbitrarily controlled, and a granular explosive which does not generate cyan components in the post-gas, hardly separates components, and does not change with time can be obtained. Was.

Claims (2)

[Claims] 1. A granular explosive comprising a porous prill ammonium nitrate, a fuel substance and an inorganic hollow body having a bulk specific gravity of 0.10 to 0.30. 2. The inorganic hollow body has an average particle size of 0.2 to 4.5.
The granular explosive according to claim 1, which is in mm.