JP2006256927A - Ammonium nitrate fuel oil explosive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ammonium nitrate fuel oil (ANFO) explosive prepared by mixing porous prill ammonium nitrate, fuel oil and a phlegmatizer used also as a specific gravity control agent wherein the detonation velocity is increased and the power is enhanced by solving a defect that the explosive is easily aggregated by static electricity to improve the dispersibility without damaging the advantages when an organic-based one is used as the phlegmatizer used also as the specific gravity control agent. <P>SOLUTION: In the ammonium nitrate fuel oil (ANFO) explosive prepared by mixing the porous prill ammonium nitrate, the fuel oil and the phlegmatizer used also as the specific gravity control agent, the phlegmatizer used also as the specific gravity control agent is an organic phlegmatizer used also as a specific gravity control agent coated with an antistatic agent. The ammonium nitrate fuel oil (ANFO) explosive is obtained by blending 6 wt% light oil in 94 wt% prill ammonium nitrate and further blending 2 wt% foaming polystyrene coated with the antistatic agent ANDO29A (brand name) at the outside rate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an industrial explosive used for blasting operations in mining and civil engineering construction work, and in particular, to an ammonium explosive explosive (hereinafter referred to as “ANFO explosive”) in which fuel oil is blended with nitrate.

  ANFO explosives based on porous prill ammonium nitrate are relatively easy to manufacture, are inexpensive and easy to load into blast holes, and are detonated by the Japanese Society of Fire Pharmacy (IV) ES-32 (2) In the PVC gutter test or carton test specified as the detonation test method, there is an advantage such as high safety because of the low sensitivity that does not completely explode with the No. 6 detonator, but the consumption cost is further reduced from the consumer. One way to reduce the cost is to reduce the bulk specific gravity of the ANFO explosive to reduce the amount of the ANFO explosive used per unit volume of the loading hole, that is, to improve the porosity of the porous prill ammonium nitrate. In addition, attempts have been made to reduce the density of ammonium nitrate particles by adding a foaming agent.

On the other hand, the decrease in the density of ammonium nitrate increases the specific surface area of the ammonium nitrate particles to increase the contact area between the porous prill ammonium nitrate and the fuel oil, thereby improving the reactivity of the ANFO explosive and increasing the sensitivity. Conventionally, to reduce the reactivity of ANFO explosives, glass hollow spheres (glass microballoons), inorganic hollow bodies such as panlite with a multi-bubble structure in which natural glass is expanded, organic hollow bodies such as exvancells and expanded polystyrene, etc. It has been disclosed in Patent Document 1 below that a specific gravity adjusting agent / desensitizing agent comprising the above has been used.
JP 2003-137684 A

  Among the above-mentioned desensitizing agents, the organic type has a wider range of adjustment of specific gravity than the inorganic type and has the advantage of good performance of the ANFO explosive, but the inorganic type is less charged and dispersible. On the other hand, there is a problem that it is easily charged and agglomerated due to static electricity, and its dispersibility is poor.

  An object of the present invention is to provide an ANFO explosive that solves the above problems without impairing the performance when an organic material is used as a specific gravity adjusting agent and desensitizing agent.

  The present invention relates to an ANFO explosive comprising porous prill nitrate, fuel oil, a specific gravity adjusting agent and a desensitizing agent, and an organic specific gravity adjusting agent which is coated with an antistatic agent in the specific gravity adjusting agent and desensitizing agent. It is a desensitizing agent.

  As the fuel oil used in the present invention, a light oil having a flash point of 50 ° C. or higher as defined in the JIS K 4801 ammonium nitrate explosive can be used, and as an organic specific gravity adjusting agent and desensitizing agent, For example, organic hollow bodies such as the above-mentioned expand cell and expanded polystyrene can be used.

  Further, as the antistatic agent, for example, PANDO29A (trade name) manufactured by Three Bond Co., Ltd., sorbitan trioleate (trade name “Leodor SP-030”) manufactured by Kao Corporation as shown in the following examples, and the like are used. Can do.

  According to the ANFO explosive of the present invention, the organic type used as the specific gravity adjusting agent and desensitizing agent can lower the bulk specific gravity compared to the inorganic type, and can be foamed, especially foaming. Since the bulk specific gravity can be further reduced, the range of adjustment of the specific gravity can be expanded, the dispersibility is improved by coating the antistatic agent, and the flammability is good, so the explosion speed is increased and the power is improved. There are effects such as being able to.

  Mixing 6% by weight of light oil with 94% by weight of prill nitrate manufactured by Mitsubishi Chemical Co., Ltd. and 2% by weight of expanded polystyrene made by Sekisui Chemical Co., Ltd. coated with antistatic agent PANDO29A (trade name) manufactured by ThreeBond Co., Ltd. An ANFO explosive was obtained by blending outside. And the bulk specific gravity of the obtained ANFO explosive was calculated | required as follows.

Bulk specific gravity 50 g of a sample was weighed and loaded into a 100 ml measuring cylinder, and then the measuring cylinder was dropped (tapped) from a height of about 50 mm above a rubber plate having a thickness of about 6 mm. After repeating this tapping 50 times, the volume of the sample was read from the scale of the graduated cylinder, and the bulk specific gravity was determined from the following equation (1).
Bulk specific gravity g / ml = Weighed value (g) / Volume (ml) (1)

  Next, the above-mentioned ANFO explosive was subjected to the drop sensitivity test, friction sensitivity test and electrostatic sensitivity test according to the applicant's in-house regulations specified in JIS K 4810: 2003 as follows. Asked.

Drop drop sensitivity test A sample is placed between two cylindrical rollers and placed on the anvil of the test machine. An iron drop is dropped on the sample to determine the sensitivity of the explosive from the relationship between drop height and explosion state. 1 shows a grade table defined in JIS K4810.

  At each drop height, the test is performed 6 times in succession, and the grading is, for example, 1-6 times when the iron hammer is dropped from a height of 20 cm, and the iron hammer is dropped from a height of 15 cm. Assuming that the number of explosions when dropped is 0, from Table 1, the drop sensitivity of the explosive of the sample is grade 4.

Friction sensitivity test The sample is sandwiched between a magnetic friction rod and a friction plate attached to a testing machine, and the frictional motion is performed with a load applied. The friction sensitivity of the explosive is determined from the relationship between the load and the explosion state. Table 2 shows the grade table specified in JIS K4810.

  The experiment was performed six times for each load, and the grading is 39.2N, for example, when the number of explosions is 1 or more, and 19.6N is 0. From Table 2, the sensitivity of the sample is 3 Class.

Electrostatic Sensitivity As shown in FIG. 1, using a fixed electrode device in which the upper electrode is a spherical electrode 1 having a diameter of 3 mm in high-strength brass and the lower electrode is a flat electrode 2 made of high-strength brass, a thickness is formed on the lower electrode. A flat plate 4 having a hole 3 having a diameter of 4 mm is placed in the center of a sheet made of Teflon (registered trademark) having a width of 0.5 mm and a width of 20 mm, and the sample is filled in the hole 3. Then, a Mylar tape (not shown) with a pinhole on it is placed and pasted so that the pinhole is located at the center of the hole, and the discharge energy is adjusted to 0.1-1 mm with the height gauge scale. The discharge energy is divided into 1 to 5 ranks, ranked according to the discharge energy up to the explosion state, and rank 5 that does not ignite when discharge energy of 100 mJ or more is discharged. .

  Next, for the above-mentioned ANFO explosive obtained in the examples, the explosion speed was measured by the ion gap method according to the explosion speed test specified in JIS K 4810: 2003 as follows.

Explosive speed test As shown in FIG. 2, the bottom of a steel pipe 6 having an inner diameter of 36 mm and a length of 250 mm is covered with a cardboard 7 and fixed with paper tape, and then the above ANFO explosive 9 obtained in the embodiment is tapped in the steel pipe. While filling up to the height of the steel pipe, it was detonated with No. 6 electric detonator 8 using 50 g of Super Zeramite (trade name), which is a booster manufactured by Chuka Kayaku Co., Ltd. The explosion speed was measured by two ion gaps 13 inserted into the steel pipe 6 with an interval of 100 mm.

Next, an initiation sensitivity test was conducted to determine whether or not to initiate the explosion with the No. 6 electric detonator 8 according to a PVC rain gutter test defined as a detonation initiation test method in the standard of pyrotechnic association (IV) ES-32 (2).
The above results are shown in Table 3 below.

Comparative example

The ANFO explosive compounded with 94% by weight of prill nitrate and 6% by weight of light oil is the same as the prill nitrate used in the examples, and its bulk specific gravity, drop sensitivity, friction sensitivity, electrostatic sensitivity, explosion speed, initiation sensitivity by No. 6 electric detonator Was obtained in the same manner as in Example.
The above results are shown in Table 3 below.

  As can be seen from Table 3, the ANFO explosive of the example had a lower bulk specific gravity than the ANFO explosive of the comparative example, but the explosion speed was improved by 10 several percent, and otherwise, there was no change.

The figure which shows the instrument used for the electrostatic sensitivity test. Sectional drawing of the sample used for the explosion speed test and the initiation sensitivity test by No. 6 electric detonator.

Explanation of symbols

1. ・ Spherical electrode 2 ・ ・ Plate electrode 3 ・ ・ Hole 4 ・ ・ Plate 6 ・ ・ Steel tube 7 ・ Cardboard 8 ・ No.6 electric detonator 9 ・ ANFO explosive 11 ・ ・ Booster 13 ・ ・ Ion gap

Claims (1)

  In ANFO explosives that are composed of porous prill nitrate, fuel oil, specific gravity adjusting agent and desensitizing agent, the above specific gravity adjusting agent and desensitizing agent is an organic specific gravity adjusting agent and desensitizing agent coated with an antistatic agent. An anti-nitrile explosive characterized by being.

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