JPH11322481A - Explosive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an excellent antistatic effect without causing solidification of ammonium nitrate in an ANFO explosive by compounding a fatty acid amide in a compsn. comprising ammonium nitrate and fuel oil. SOLUTION: Ammonium nitrate, fuel oil and a fatty acid amide are incorporated into an explosive compsn. The fatty acid amide is preferably a >16C fatty acid amide or bisamide. The fatty acid amide is preferably incorporated by about 0.01 to 4.5 wt.% of the compsn. As for the ammonium nitrate, porous prill ammonium nitrate or a mixture of porous prill ammonium nitrate and its pulverized compd. is preferably used. The fatty acid amide is used as a lubricant to improve slipping property and blocking preventing property between substances. The fatty acid amide used is, for example, oleylamide, stear stearylamide, N,N'-methylene bis(stearylamide) or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to explosive compositions. More particularly, the present invention relates to an ammonium nitrate (ammonium nitrate) explosive composition which is widely used in industrial blasting operations such as crushed stone and mining, and is directly loaded into perforations of objects to be destroyed.

[0002]

2. Description of the Related Art Dynamite, hydrous explosives, nitric acid explosives, ANFO explosives and the like are well known as explosives used in industrial blasting operations. Explosives for crushed stone and mining
ANFO explosives are often used because of their advantages in that they are highly safe in production and handling, are inexpensive, and can be directly poured into perforations.

[0003] When the ANFO explosive is fed at a high speed by a pneumatic conveying type loading machine for loading into a blast hole or when pouring is loaded, friction between explosive particles or explosive particles and a hose wall surface or a material to be destroyed is destroyed. A large amount of static electricity is generated by friction with the wall. Once generated static electricity is A
The NFO explosives themselves, which gradually accumulate in blast holes, hoses and loaders, may cause an explosion accident due to discharge to an electric detonator.

Further, ammonium nitrate is used as the main component of the ANFO explosive and often accounts for 90% by weight or more of the explosive composition. As the nitrate, porous granular nitrate (hereinafter referred to as porous prill nitrate) is often used.
Since nitric acid has a property that its solubility in water rapidly increases at high temperatures, at high temperatures such as summer, the surface of nitric acid partially dissolves by moisture in the air, etc., and at low temperatures, crystals precipitate from the dissolved surface. By repeating this, there is a problem that the entire ANFO explosive is solidified (called solidification).

As countermeasures against static electricity, use of an anti-static detonator, a loading hose having conductivity, and the like have been performed. Also,
In general, water in a substance is effective in preventing the charge of the substance itself.
Explosives may be included. But,
The former is a passive measure premised on the generation of a large amount of static electricity and cannot be said to be a fundamental solution. Although the latter is effective as a countermeasure against static electricity, the addition of an aqueous solution often results in the promotion of solidification of the ANFO explosive.

[0006]

In ANFO explosives, it is desired to establish a measure for preventing charging efficiently without solidifying the ammonium nitrate used therein.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result of adding fatty acid amide as a compounding component of the ANFO explosive, solidification of the ANFO explosive was not caused. The present inventors have found that an excellent antistatic effect can be obtained, and have completed the present invention.

That is, the present invention provides an explosive composition comprising (1) ammonium nitrate, a fuel oil and a fatty acid amide, and (2) a fatty acid amide comprising C16 (having 1 carbon atom).
6) The above fatty acid amide or bisamide (1)
The explosive composition of (1) or (2), wherein the fatty acid amide is contained in the explosive composition in an amount of 0.01 to 4.5% by weight.
The explosive composition according to any one of (1) to (3), wherein (4) ammonium nitrate is porous prill ammonium nitrate,
(5) The explosive composition according to any one of (1) to (4), wherein the ammonium nitrate is a mixture of porous prill ammonium nitrate and a crushed product thereof.

Hereinafter, the present invention will be described in detail. The fatty acid amide used in the present invention is used as a lubricant to improve slip properties between substances and anti-blocking properties.
Fatty acid amides or bisamides having 6 (C16) or more are preferable, and fatty acid amides or bisamides having C16 (C16) to C38 (C38) are more preferably used. Specific examples of the fatty acid amide that can be used include oleic acid amide, stearic acid amide, N,
N'-methylenebis (stearylamide), N, N'-
It is an amide or bisamide of a higher fatty acid such as ethylenebis (stearylamide) or methylol stearylamide.

If the amount of the fatty acid amide used in the explosive composition of the present invention is too small, the antistatic effect is not sufficient, and if it is too large, the performance of the explosive may be reduced. The content is usually 0.01 to 4.5% by weight, preferably 0.1 to 3% by weight.

In the explosive composition of the present invention, it is preferable to use porous prill nitrate as ammonium nitrate. As porous prill nitrate, porous prill nitrate having an oil absorption of 5 to 24% by weight, an average particle diameter of 0.5 to 2.5 mm, and a hardness of 4 to 25 is preferable. Porous prill ammonium salt is usually contained in the explosive composition in an amount of 70 to 97% by weight, preferably 90 to 97% by weight.
９５95% by weight.

The oil absorption rate of ammonium nitrate is measured by immersing a fixed amount of sample nitric acid in light oil for a fixed period of time, filtering by suction, and measuring 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 apparatus. Inject 40 ml of light oil into a glass filter, stir well with a fine rod, and mix and contact ammonium nitrate and light oil. After leaving for 5 minutes, open the lower cock attached to the glass filter,
Let light oil flow naturally for 2 minutes. Subsequently, after suctioning with a vacuum pump for 5 minutes (flow rate of about 30 ml / min), the glass filter containing the sample nitric acid adsorbing light oil is weighed with an upper plate direct balance. The increase is the light oil adsorption. 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 (1).

Oil absorption rate (%) = light oil adsorption (g) / sample 50 (g) × 100 (1)

The oil absorption rate of ammonium nitrate mainly depends on the pore volume and effective diameter distributed inside the grains.
For example, if the pore volume is large, the space that can hold light oil inside the grains becomes large, so that the oil absorption rate becomes large.

The average particle size of ammonium nitrate is measured from a weight distribution of each of a certain amount of ammonium nitrate through various sieves having different sieves. The calculation formula is as shown in the following formula (2).

D = Σ (X × R / 100) (2) where D = average particle size (mm) X = average size of sieve mesh (mm) R = residue weight on sieve mesh (%)

The hardness of the porous prill ammonium nitrate is measured by mechanically crushing a fixed amount of a sample of the porous prill ammonium nitrate under a predetermined condition using a hardness measuring device, and observing the amount of the crushed sample. The apparatus used for the measurement is a pan (200 mm in diameter) that rotates together with a rotation axis fixed horizontally on a vertical rotation axis that rotates through a speed reducer, and a non-rotating grinding dish (190 mm in diameter) that is dropped on the pan. , Weight 1
715 g). 50 g of sample nitrate is placed in a tray of a hardness measuring device, spread evenly over the entire surface of the plate, and a grinding plate is superimposed thereon, and the device is started. 40r. p. m
After starting for 15 seconds, the apparatus is stopped, and after stopping, the tray is taken out, the sample in the sieve is put into a predetermined sieve, and shaken for 1 minute using a shaker. Then, a crushed product passed through a sieve is collected, weighed, and displayed as a ratio (%) of the crushed amount (g) to 50 g of the original sample nitrate. The calculation formula is as shown in the following formula (3).

Hardness (%) = Amount of crush (g) / Sample 50 (g) × 100 (3)

The ammonium nitrate used in the explosive composition of the present invention may be a mixture of granular ammonium nitrate and crushed ammonium nitrate. In this case as well, porous prill nitrate is used as ammonium nitrate, and pulverized porous prill nitrate may be used as a pulverized product of ammonium nitrate. The pulverized product of porous prill nitrate can be obtained, for example, by pulverizing porous prill nitrate having an oil absorption of 5 to 24% using a general pulverizer such as a ball mill or an edge runner that pulverizes a solid into a powder. The average particle size of the pulverized product is 0.01 to 0.5
mm, preferably 0.01 to 0.3 mm.

In the present invention, porous prill ammonium nitrate and its pulverized product can be mixed in any ratio.
The mixing ratio is usually 20 to 80% by weight for the former and 8 for the latter.
0 to 20% by weight.

As the fuel oil used in the explosive of the present invention, a fuel oil which is liquid at the time of mixing is used. Specific examples of fuel oils that can be used include mineral oils such as No. 2 light oil and kerosene,
Animal oils and the like. Further, 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 in combination as a fuel oil depending on the use.
Fuel oils with a high melting point can be used by mixing with ammonium nitrate above the temperature at which it becomes liquid.

In the present invention, the fuel oil amount is usually 2.5 to 25% by weight, preferably 4 to 10% by weight in the explosive composition.
% By weight.

As is well known to those skilled in the art, the explosive of the present invention may contain, if necessary, an oxidizing agent other than ammonium nitrate or a crushed product thereof, for example, potassium nitrate or perchlorate, and additionally powder such as wood powder or Al powder. It is possible to add fuel or other additives.

In the explosive of the present invention, the fatty acid amide is dissolved or dispersed in fuel oil and mixed with porous prill nitrate using a mixer such as a kneader or a rotary mixer, or mixed with porous prill nitrate and light oil using a similar mixer. After that, the fatty acid amide is added and mixed. Other mixers can of course be used as long as they have stirring and mixing functions. When using fuel oil with a high melting point,
It is preferable to use a mixer equipped with a heating and warming device.

The explosive composition of the present invention exhibits an excellent antistatic effect and has a characteristic that it is extremely hard to solidify even at high temperature and high humidity.

[0026]

EXAMPLES 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 and% is% by weight.

Example 1 93.7 parts of porous prill nitrate having an oil absorption of about 10%, an average particle diameter of about 1.2 mm and a hardness of about 12 were transferred to a horizontal kneader equipped with a sigma blade at room temperature, and subjected to fatty acid amide (manufactured by Kao Corporation). Then, 6 parts of No. 2 light oil in which 0.3 part of fatty acid amide S (trade name) was dissolved was added and mixed at 80 rpm for 5 minutes to obtain an explosive composition of the present invention.

EXAMPLE 2 93.7 parts of the same porous prill nitrate as in Example 1 were transferred to a rotary mixer (concrete mixer) at room temperature.
N'-ethylenebis (stearylamide) (manufactured by Kao Corporation,
6 parts of No. 2 light oil in which 0.3 part of Kaowax EB-FF (trade name) was dissolved was added and mixed at 70 rpm for 5 minutes to obtain an explosive composition of the present invention.

Example 3 50 parts of the same porous prill ammonium nitrate as in Example 1 and 43.9 parts of its pulverized product (average particle size: 0.1 mm) were transferred to a horizontal kneader equipped with sigma blades at room temperature. Add 8 parts
Mix for 5 minutes at 0 rpm. Thereafter, 0.1 part of a fatty acid amide (the above-mentioned fatty acid amide S) was added and mixed at the same rotation speed for 2 minutes to obtain an explosive composition of the present invention.

Comparative Example 1 94 parts of the same porous prill nitrate as in Example 1 was transferred to a horizontal kneader equipped with a sigma wing at room temperature, and 6 parts of No. 2 light oil was added and mixed at 80 rpm for 5 minutes to obtain a comparative explosive. Was.

For each of the explosives obtained in Examples and Comparative Examples, the degree of solidification, electrostatic potential and explosion velocity were measured.

The sample used for measuring the degree of solidification has an inner diameter of 50 m.
Each explosive is placed in a cylindrical container made of PVC, 300 mm high and 300 mm high.
While putting a 2.7kg load on it,
This was obtained by repeating a cycle of heating at a temperature of 40 ° C. for 8 hours and then cooling at 20 ° C. for 16 hours once.

The degree of solidification is measured by using bolts and nuts so that the rod moves only vertically in a column installed on a table that does not move even if a load is applied to the end of the rod having a length of 500 mm. The above-described sample was placed at a position 100 mm from the end, a load was gradually applied to the side opposite to the fixed end, and the load was measured by reading the load at which the shape of the sample collapsed. Therefore, it is evaluated that the larger the measured value is, the more solidified it is.

At a temperature of 10 ° C. and an absolute humidity of 5 g · H ₂ O / kg · air, the electrostatic potential was measured by laying a policyt on an aluminum spout having a length of 1820 mm and inclined at 45 degrees and placing the policyt on the upper end of the spout. 500 g of each explosive is poured out from the attached hopper at a rate of 100 g / sec, and a diameter of 60 m is provided at a position 700 mm from the upper end of the spout.
100m perpendicular to the back of the spout
The measurement was performed by reading the electrostatic potential generated in the policy using a current collecting potential measuring instrument (KS-525, manufactured by Kasuga Electric) having the sensor fixed at a distance of m. The above is based on the Pharmaceutical Society of Japan standard (ES-81).

The measurement of the explosion velocity is performed according to the standard of the Pharmaceutical Society of Japan (ES-
41 (1)), and 150 g of each explosive is 0.88 in specific gravity
35mm inside diameter, 3mm thick, 230m long
m, put it in a steel tube and use it as a booster
Was carried out by the Doitlish method.

Table 1 shows the measurement test results of the solidification degree, electrostatic potential and explosion velocity of each explosive.

[0037]

Table 1 Performance of each explosive composition Solidification degree (kg) Electrostatic potential (-kV) Explosion speed (m / sec) Example 1 0.5 10 2880 Example 2 0.3 12 2850 Example 30 0.7 20 2890 Comparative Example 1 7.0 100 2850

As is clear from Table 1, the degree of solidification is very strong in Comparative Example 1, whereas Examples 1 to 3 cannot be said to be solidified. Regarding the electric potential, the higher antistatic property in Examples 1 to 3 is apparent as compared with the comparative example. Further, as is clear from Examples 1 to 3, the explosion velocity has no negative influence due to the addition of the fatty acid amide.

[0039]

According to the present invention, it is possible to obtain an explosive composition which has high antistatic properties and has a characteristic that it hardly solidifies even at high temperature and high humidity.

Claims (5)

[Claims] 1. An explosive composition comprising ammonium nitrate, a fuel oil and a fatty acid amide. 2. The explosive composition according to claim 1, wherein the fatty acid amide is a fatty acid amide or a bisamide having C16 (C16) or more. 3. The method of claim 1, wherein the fatty acid amide is contained in the explosive composition in an amount of 0.01 to 0.01%.
The explosive composition according to any one of claims 1 to 2, comprising 4.5% by weight. 4. The explosive composition according to claim 1, wherein the ammonium nitrate is porous prill ammonium nitrate. 5. The explosive composition according to claim 1, wherein the ammonium nitrate is a mixture of porous prill ammonium nitrate and a pulverized product thereof.