JPH07223887A - Hardly electrified self-flowing explosive composition - Google Patents

Abstract

PURPOSE:To obtain a hardly electrified, water-resistant and self-flowing explosive composition having enhanced water resistance and hardly electrifying properties. CONSTITUTION:This composition comprises a powdery or a granular mixture composed of an ammonium nitrate fuel oil (ANFO) explosive or ammonium nitrate and/or other oxidizing agents, a microcrystalline wax or a paraffin wax which has >=60 deg.C melting point and is solid at normal temperature and a metallic salt of a fatty acid. The powdery or granular mixture and the metallic salt of the fatty acid are coated with the microcrystalline wax or paraffin wax which has >=60 deg.C melting point and is a solid at normal temperature in a molten state. The metallic salt of the fatty acid is calcium stearate or a mixture of the calcium stearate with an alkaline earth metallic salt of stearic acid such as barium stearate, magnesium stearate or zinc stearate and the amount thereof is <=0.5wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-flowing type explosive composition having water resistance and antistatic property.

[0002]

The most popular powdered or granular self-flowing explosive is the ANFO explosive, which is widely used in the lithotripsy industry. Recently, it has also been used in mines with advanced ventilation.

However, the ANFO explosive has drawbacks such as lack of water resistance and low specific gravity. Therefore, when it is used in wet or water holes, its component, ammonium nitrate, dissolves in water and explodes. It often loses its sex and becomes non-explosive.

Therefore, in order to overcome it, a blasting agent called a heavy ANFO explosive, which is a mixture of ANFO explosive and an emulsion composition, has been put on the market and widely used in various countries.

[0005]

However, although this explosive agent overcomes its drawbacks as compared with conventional ANFO explosives, it is expensive and is for site mixing, so after mixing, within the same day. Although there is no problem as long as it is used, considering the actual situation in Japan, site mixing is not possible, and separation starts while the manufactured product is stored in the explosive store, resulting in deterioration of performance or non-explosion. Sometimes it becomes.

On the other hand, the conventional self-flowing explosive composition is
It is known that water is mixed with wax or the like instead of light oil which is a fuel for FO explosives (see Japanese Patent Laid-Open No. 2-221178).

This is a powdery or granular explosive composition itself which is rendered water repellent in order to make the powdery or granular explosive composition itself water resistant. The simplest method of coating the powdery or granular explosive composition with wax is taken as the means.

However, although this conventional self-flowing explosive composition has water resistance, it hardly functions with respect to charging property. The present inventor presupposes that work is performed by an ANFO loader (automatic loading device) that has been conventionally used, rather than an explosive that does not match the actual situation in Japan, such as the heavy ANFO explosive described above. It has been completed by proceeding with research on powdery or granular explosive compositions that can be easily loaded into boreholes, have water resistance, and are hardly charged.

The present invention has been made on the basis of such knowledge, and an object thereof is to provide a hardly-charged water-resistant self-flowing explosive composition having improved water resistance and hardly-charged property.

[0010]

The invention of claim 1 is ANFO.
A powdery or granular mixture of explosives or ammonium nitrate and / or other oxidizers, a microcrystalline wax and / or paraffin wax having a melting point of 60 ° C. or higher and solid at room temperature, and a fatty acid metal salt.

According to the second aspect of the present invention, the powdery or granular mixture of ANFO explosive or ammonium nitrate and / or other oxidant has a melting point of 60 ° C. or higher and solid microcrystalline wax and / or paraffin wax in a molten state. It is coated.

According to the invention of claim 3, the powdery or granular mixture of ANFO explosive or ammonium nitrate and / or other oxidizing agent and the fatty acid metal salt are microcrystalline wax and / or paraffin having a melting point of 60 ° C. or higher and solid at room temperature. The wax is coated in a molten state.

According to a fourth aspect of the present invention, the fatty acid metal salt is calcium stearate or a mixture of calcium stearate and an earth stearate metal salt such as barium stearate, magnesium stearate or zinc stearate.

According to a fifth aspect of the present invention, the proportion of the fatty acid metal salt is 0.5% by weight or less.

[0015]

First, as described above, it is obvious that the powdery or granular explosive composition itself is made water repellent in order to make the powdery or granular explosive composition itself water resistant. The easiest way is to coat the granular explosive composition with wax.

Ammonium nitrate, which is the main component of the explosive, has an oxygen balance of +0.20, and by adjusting the amount of the wax to be coated, the oxygen balance can be adjusted to a preferable value for the explosive composition.

The explosive composition thus obtained can impart water resistance, but when the ANFO explosive is loaded using the ANFO loader, the particles themselves are charged with static electricity due to fluid friction between the particles. . This charge can sometimes reach a sufficient amount of energy to detonate an electric detonator.

Therefore, in order to reduce the amount of electrification or to prevent almost electrification, each component is coated with a fuel which becomes liquid when heated at room temperature. The fuel, which is solid at room temperature and becomes liquid when heated, refers to microcrystalline wax and / or paraffin wax having a melting point of 60 ° C. or higher and solid at room temperature.

Further, a water repellent fatty acid metal salt, especially calcium stearate, or calcium stearate and barium stearate was added to microcrystalline wax and / or paraffin wax having a melting point of 60 ° C. or higher at room temperature in combination. By coating a powdered or granular explosive composition with a substance, it is possible to impart far superior antistatic properties to conventional ANFO explosives.

As a concrete method, for example, there is the following method. The powdery or granular explosive composition and the fatty acid metal salt are separately stirred and heated, and when the temperature reaches the melting point of the wax or higher, the previously melted wax is added and sufficiently mixed at the temperature higher than the melting point of the wax. .

The powdery or granular explosive composition and the fatty acid metal salt are heated with stirring, and when the temperature exceeds the melting point of the wax, the wax which has been melted in advance is added,
Mix well at a temperature above the melting point of the wax.

Solid waxes are individually added to the powdery or granular explosive composition and the fatty acid metal salt at room temperature, and the mixture is heated with stirring and sufficiently mixed when the temperature reaches the melting point of the wax or higher.

At room temperature, powdery or granular explosive composition, fatty acid metal salt and solid wax are added and heated with stirring, and when the temperature reaches the melting point of the wax or higher, sufficient mixing is performed.

[0024]

EXAMPLES The present invention will be described in detail below with reference to examples. Tables 1 to 4 show the compounding compositions, their ratios, and characteristics of this example.

In Tables 1 to 4, sample Nos. 6 to 14 and 17
-18, 20-23, 25-30, 32, 33 are examples of the present invention, and sample Nos. 0-5, 15-16, 19, 24, 31 are comparative examples.
Sample No. 0 is 94% by weight of prilled ammonium nitrate (manufactured by Mitsubishi Kasei Co., Ltd.), 5.9% by weight of No. 2 light oil (manufactured by Nippon Oil Co., Ltd.), and an antistatic agent (NONION NS-206 manufactured by NOF CORPORATION). It is a conventional ANFO explosive with 0.1% by weight added.

In Samples Nos. 1 to 33, ammonium nitrate was heated with stirring, and when the temperature reached the melting point of the wax or higher, the wax which had been melted in advance was added, and the mixture was sufficiently mixed at the temperature higher than the melting point of the wax for trial manufacture. did.

Sample Nos. 6-18, 20-23, 25-30, 32, 33
Then, the stearic acid metal salt was mixed in advance with ammonium nitrate while stirring. Each composition in Table 1 and Table 2 will be described.

The prilled ammonium nitrate is manufactured by Mitsubishi Kasei Co., Ltd. The wax item Hi-mic 2065 is Microcrystalline wax manufactured by Nippon Seiro Co., Ltd., biscuware 195A is Microcrystalline wax manufactured by Barico, Petronauber C is oxidized wax manufactured by Barico, and paraffin 150 is manufactured by Nippon Seiro. Paranox 205, a paraffin wax manufactured by Wax Co., Ltd., is a synthetic wax manufactured by Nippon Oil Co., Ltd.

Calcium stearate in the item of water repellent,
Barium stearate, magnesium stearate, zinc stearate, copper stearate and stearic acid are all reagents.

Each composition in Tables 3 and 4 will be described. Prilled ammonium nitrate is manufactured by Mitsubishi Kasei Co., Ltd., granular ammonium nitrate is manufactured by Mitsubishi Kasei Co., Ltd.,
Sodium perchlorate is a reagent, and sodium nitrate is a product of Mitsubishi Kasei.

Carbon balloon A200 of the item of specific gravity adjusting agent
The Expancel 551DE80 manufactured by Kureha Chemical Co., Ltd.
Expancel Co., Ltd., phenol resin BJ-0930
Is an acrylonitrile resin F manufactured by Union Carbide
80ED is manufactured by Matsumoto Yushi Co., Ltd., and GMB K-25 is manufactured by 3M Company.

Calcium stearate and barium stearate are reagents. Each item in Tables 1 to 4 will be described. The density was calculated from the ratio of the net weight of the contents to the volume of the steel pipe, by pouring the sample into an explosive steel pipe with an inner diameter of 53 mm and a length of 350 mm, capping it when the mouth was filled.

The electrostatic charge amount was tested according to the industrial explosive standard ES-81. Room temperature 24-26 ° C, humidity 42-46% RH,
Numerical values were taken 10 times each in the maximum absolute value in the sample, and + and-were given according to the polarity. The electric field strength meter is made by Hugle
del 12C, capacitance meter set is made by Advantech, Faraday cage, amplifier, electrometer TR8031, TR84 respectively
01 and TR8411.

The charging energy is E max = 1 from the maximum potential V max and the maximum charged charge Q max in each sample 10 times.
Maximum charging energy E max based on / 2Q max · V max
I asked.

The method of measuring the explosive velocity of an explosive sample is as follows. The sample was filled in a steel pipe having an inner diameter of 53 mm, a wall thickness of 3.9 mm and a length of 350 mm, and was embedded in sand 20 cm, and an explosive of 30 mm in diameter and 100 g of emulsion explosive (Nippon Koki Co., Ltd .: 1EA) was used as a booster. Explosion speed is 5 from the bottom of the steel pipe
An optical fiber was inserted at a position of 0 and 150 mm for measurement.

The method of measuring the explosive property of an explosive sample is as follows. J sample with inner diameter of 35.7 mm, wall thickness of 3.5 mm and length of 1000 mm
It was filled in an IS steel pipe, embedded in sand in 20 cm, and detonated by using an emulsion explosive with a diameter of 30 mm and 100 g (Nippon Koki Co., Ltd .: 1EA) as a booster. As for the explosive property, the detonator wire of 25 grains is inserted into the bottom of the steel pipe by 30 mm, and the steel wire is attached to the detonator wire at the other end, and the explosive wire explodes due to the explosion of the sample. When it was completed, it was judged that the sample had transmitted.

The method of measuring the dissolution rate is as follows. sample
Wrap 200g in gauze, soak in 300g of water in a 500cc beaker,
After the lapse of 30 minutes, the whole gauze was taken out, the insoluble matter in the beaker was taken out, and then a floating hydrometer was put in the solution to measure the specific gravity of the solution (this is referred to as dx).

Further, the specific gravity of the solution when completely dissolving the same amount of ammonium nitrate and water as the sample (this is defined as dmax) was measured, and the dissolution rate (%) was calculated using the following formula. Dissolution rate (%) = 100 × (dx-do) / (dmax-do)
) Here, do represents the specific gravity of water.

Next, Tables 1 to 4 will be described. Table 1
~ Sample Nos. 1 to 16 in Table 2 show how the chargeability and water resistance vary depending on the type of stearate.

From these results, it can be seen that calcium stearate is extremely effective for water resistance, and that the water resistance is almost saturated when the amount of calcium stearate is around 0.5% by weight.

Therefore, calcium stearate is
Addition of 0.5% by weight or more is not so important for water resistance, and even the performance of explosives may be deteriorated.
On the other hand, from the viewpoint of antistatic property, it was found that the effect of barium stearate was outstanding, and it was shown that the amount of barium stearate of 0.1% by weight was sufficient.

Other stearates, such as magnesium and zinc, are effective for the antistatic property, but stearic acid containing copper ions and stearic acid itself are recognized to have a remarkable effect from the viewpoint of water resistance and antistatic property. There wasn't.

Samples Nos. 1 to 5 were prepared by investigating which waxes are effective for both of them, paying attention to water resistance and antistatic property. It can be seen that the waxes that reduce the electrostatic charge amount are Hi-mic 2065, Paranock 205, and Paraffin 150.

On the other hand, from the viewpoint of the dissolution rate, Hi-mic 2065, Paranock 205 and Paraffin 150 were Hi-mic 2065.
Proves to be effective. However, even in sample No. 1 using Hi-mic 2065, the water resistance and antistatic property were not sufficient.

Sample Nos. 6 to 16 were Hi-mic 2065, and calcium stearate, barium stearate, magnesium stearate, zinc stearate, copper stearate, and stearic acid were used to impart water resistance and antistatic properties. Is added for comparison.

From this, it is found that calcium stearate is most effective in terms of the dissolution rate, and from the viewpoint of charging energy, calcium stearate, barium stearate, magnesium stearate, and zinc stearate are effective. It can be seen that the water resistance is insufficient.

Samples Nos. 6 to 10 were prepared by investigating the amount of calcium stearate added. From this, addition of 0.3% by weight or more of calcium stearate does not significantly contribute to the poor electrification resistance and water resistance, and it is also included in explosives. It is understood that the inclusion of an inactive component causes a decrease in explosive performance, which is not preferable.

Therefore, as an example, it is understood that when calcium stearate having a water resistance effect and barium stearate having an antistatic effect are used in combination, both effects are exhibited, and a composition meeting the object of the present invention is obtained. This is sample Nos. 17 and 18 in Table 3.

Sample Nos. 19 to 27 are those in which granular ammonium nitrate was used instead of prill ammonium nitrate. Sample No. 20 is a mixture of calcium stearate and barium stearate used as a mixture of stearates, and has improved water resistance and antistatic property.

Other than sample No. 20, barium stearate was not added to some of them, but the effect of slightly antistatic property was recognized, and it was found that the effect of improving water resistance was greater than that.

Basically, since Sample Nos. 19 to 27 are granular ammonium nitrate, there are no bubbles that should be hot spots necessary for detonation propagation, and it can be said that they are not explosive. Therefore, when granular ammonium nitrate is used, it becomes explosive by adding the foaming agent. For example, the half-explosion of Sample Nos. 20, 22, 23, and 27 is equivalent to that, and the explosive property is obtained by increasing the power of the booster, increasing the drug diameter, or increasing the degree of sealing. By the way, if the booster is changed to RDX 50g pellets (BAM type steel pipe sample booster), for example, Sample No. 23 can obtain an explosion velocity of 3560 m / sec.

Sample Nos. 28 to 30 are those in which sodium perchlorate was added as an oxidizing salt in addition to the above. The explosion rate was not so high, but it was explosive and the effect of adding sodium perchlorate was high. Has been obtained.

It is assumed that a higher explosion speed can be obtained by increasing the diameter of the medicine, strengthening the booster, or increasing the degree of sealing as in the above case. Sample Nos. 31 and 32 are those in which prill ammonium nitrate and granular ammonium nitrate are used in combination, and they have an explosive property even without adding a foaming agent.

Sample No. 33 is obtained by adding sodium nitrate to Sample Nos. 31 and 32 to adjust the oxygen balance. In this example, ammonium nitrate was heated with stirring, and when the temperature was higher than the melting point of the wax, the wax that had been melted in advance was added, and the mixture was thoroughly mixed at a temperature higher than the melting point of the wax to make a trial product. Even when a solid wax was added to ammonium nitrate, heated while stirring, and sufficiently mixed at a temperature higher than the melting point of the wax for trial production, no difference in water resistance was observed.

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

[Table 3]

[0058]

[Table 4]

[0059]

As described above, according to the present invention, by adding a fatty acid metal salt to a water-resistant self-flowing explosive composition, the water-proof self-flowing explosive composition is remarkably water resistant as compared with a conventional electrostatic self-flowing explosive composition. And the antistatic property can be improved.

Therefore, the electrostatic charge amount due to the flow friction between particles of the explosive composition at the time of loading by the ANFO loader is reduced or hardly charged, and the borehole can be easily loaded.

According to the invention, microcrystalline wax and / or paraffin wax, which is solid at room temperature and has a melting point of 60 ° C. or higher, is coated in a molten state with a powdery or granular mixture of ANFO explosive or ammonium nitrate and / or other oxidant. Therefore, the coated wax does not remelt even during storage in the explosive store, and therefore does not solidify in the explosive store and lose the self-flow property. The molten wax is coated with the oxidant as evenly as possible, so that the mixing balance of the oxidant and the fuel is maintained, the explosion efficiency is maintained, and the water-soluble oxidant is coated with the wax. This improves the water resistance.

Further, according to the present invention, in addition to the above-mentioned reason, the water resistance is further improved by mixing the fatty acid metal salt with calcium stearate, and any of barium stearate, magnesium stearate and zinc stearate is further improved. Mixing one of them with calcium stearate also contributes to the improvement of the antistatic effect other than water resistance.

Claims (5)

[Claims] 1. An ANFO explosive or a powdery or granular mixture of ammonium nitrate and / or other oxidizing agent, a microcrystalline wax and / or paraffin wax having a melting point of 60 ° C. or higher and solid at room temperature, and a fatty acid metal salt. An antistatic water-resistant self-flowing explosive composition characterized by: 2. A powdery or granular mixture of ANFO explosives or ammonium nitrate and / or other oxidizers is coated with molten microcrystalline wax and / or paraffin wax in a molten state at a room temperature and a melting point of 60 ° C. or higher. The antistatic water resistant self-flowing explosive composition according to claim 1. 3. A powdery or granular mixture of ANFO explosives or ammonium nitrate and / or other oxidizers and fatty acid metal salts are microcrystalline wax and / or paraffin wax in the molten state, which have a melting point of 60 ° C. or higher and are solid at room temperature. The antistatic water-resistant self-flowing explosive composition according to claim 1, which is coated. 4. The fatty acid metal salt is calcium stearate or a mixture of calcium stearate and a stearic acid earth metal salt such as barium stearate, magnesium stearate, or zinc stearate. The antistatic water resistant self-flowing explosive composition described in 2 or 3. 5. The hardly-charged, water-resistant, self-flowing explosive composition according to claim 1, wherein the proportion of the fatty acid metal salt is 0.5% by weight or less.