JP2002029877A - Water resistant granular explosive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop an explosive composition which is excellent in handling quality, such as usability in bulk like the conventional ANFO explosives and possession of a flow property, and has water resistance. SOLUTION: This water resistant explosive composition is prepared by coating an explosive composition containing porous prill ammonium sulfate or fuel oil at need with a polymer which is in the form of liquid or emulsion by heat melting in a coating process and solidifies after coating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to crushed stone, mining, coal mining,
The present invention relates to an explosive composition widely used for industrial blasting work such as digging on a steep road. More specifically, the present invention relates to a water-resistant granular explosive composition that can be used by being directly loaded into a perforation or the like.

[0002]

2. Description of the Related Art As explosives used in industrial blasting operations, dynamite, hydrous explosives, nitrous acid explosives, and nitrate oil explosives (hereinafter referred to as ANFO explosives) are well known. Of these explosives, the ANFO explosive is an explosive that can be manufactured relatively easily, and is well known as an inexpensive and highly safe explosive compared to other industrial explosives. Also, ANF
The O explosive is composed of a fluid particulate material and can be directly poured into the 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
It dissolves at 0 g and at about 100 ° C. about 950 g, and is very easily dissolved 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. Is done. However, in the former case, the explosive used is more expensive than the ANFO explosive, and the blasting cost increases. Also, in the latter case, not only does it lose the advantage that it can be easily loaded in bulk, but also a gap is created between the packaged explosive and the perforated wall, and the ANFO explosive is directly loaded into the perforated hole. As compared with the case, a sufficient blasting effect cannot be obtained. Also,
ANFO explosives packaged in such a polytube are:
When charging into the perforation, damage is caused by the sharp stones of the perforation wall, etc., and as a result, water penetrates into the inside of the package, and therefore ANF
O explosives may absorb moisture and lose explosive performance. In order to solve the above problems, explosives obtained by adding a water-absorbing agent to ANFO explosives have been developed and put into practical use (JP-A-2000-2000).
-16891). However, when using them, it is necessary to once remove water from the inside of the perforation by a drainage pump, and the number of steps in the charging operation increases.

[0005]

Means for Solving the Problems The present inventors have made the most of the advantage of the ANFO explosive, which can be used in bulk, have fluidity, and have excellent handleability, and have the water and water existing in the perforation. As a result of intensive research to develop a granular explosive with water resistance that can be used without removing intruding water, it is in the form of a liquid or emulsion by heating and melting during the coating process, and solid after coating. Porous prill nitrate coated with a polymer to be converted,
Or, if necessary, an explosive composition containing a fuel oil may be an ANF
The conventional A
The present inventors have found that they have superior water resistance as compared with NFO explosives, and have completed the present invention.

That is, the present invention relates to (1) a water-resistant granular explosive composition comprising (1) a porous prill ammonium nitrate coated with a solid polymer, (2) a porous prill ammonium nitrate coated with a solid polymer, and a fuel oil. (3) The water-resistant granular explosive composition according to (1) or (2), wherein the coating amount of the solid polymer to the porous prill ammonium nitrate is 2.5 to 40.0% by weight. (4) The water-resistant granular explosive composition according to any one of (1) to (3), wherein the form of the polymer in the coating step is a molten liquid or an emulsion, 5) The solid polymer is an acrylic resin, a styrene / butadiene resin,
The water-resistant granular explosive composition according to any one of (1) to (4), which is a polyurethane resin, a styrene-butadiene copolymer rubber, an acrylonitrile-butadiene copolymer rubber, or a mixture thereof. About.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The porous prill nitrate used in the explosive composition of the present invention preferably has an oil absorption of 5.0 to 24.0% and an average particle size of 0.5 to 2.5 mm.

The oil absorption rate of porous prill nitrate is measured 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 done. Specifically, 50 g of sample 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 the following formula (1). Oil absorption rate (%) = light oil adsorption (g) / sample 50 (g) x 100 (1)

The average particle size of the porous prill ammonium nitrate is measured from a weight distribution of each of the predetermined amounts of porous prill ammonium nitrate through various sieves having different sieves. The calculation formula is as the following formula (2). D = Σ (X × R / 100) (2) where D = average particle size (mm) X = average opening of sieve mesh (mm) R = residue weight on sieve mesh (%)

[0010] The hardness of porous prill ammonium 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 measuring the amount of the pulverized ammonium nitrate. The equipment used for measurement is a funnel for sample injection,
A flow pipe (inside diameter 16 mm, length 175 mm) connected to the compressed air inflow hole (inside diameter 4 mm, length 55 mm), and a sample injection tube (inside diameter 12
mm, length 52 mm) and a sample pulverizing tube (inner diameter 50 mm, length 315 mm) connected perpendicularly to the flow tube.

100 g of sample nitrite from which powder has been removed with a 35 mesh sieve is dropped from a funnel through a sample injection tube into a flow tube, and compressed air (4 kg / cm ² ) flowing from an inlet hole.
Thus, the sample is caused to collide with the inner wall of the pulverizing tube through the flow pipe to pulverize the sample nitrate. The sample porous ammonium nitrate after the flow is sieved with 35 mesh, the amount (N) of +35 mesh is weighed, and the ratio is expressed as the ratio (%) of the powdered amount to 100 g of the original sample ammonium nitrate. The calculation formula is as the following formula (3). Hardness (%) = 100 (g) -N (g) (3) Porous prill nitrate having a hardness of 4.0 to 25.0% is used as the explosive composition of the present invention. Is preferred.

It is preferred to use fuel oil in the explosive composition of the present invention. As the fuel oil, any combustible organic substance that is liquid at the time of mixing can be used, but specific examples of preferred fuel oils include light oil, mineral oil such as kerosene, and the like.
Vegetable oils such as soybean oil, rapeseed oil and castor oil, and animal oils such as beef tallow and 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 in combination 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 used if necessary is usually 2.5 to 2.5 times the total explosive.
It is in the range of 25.0% by weight, preferably 4.0 to 10.0% by weight.

In the present invention, as a solid polymer for coating the porous prill nitrate, any substance that forms a coating on the surface of the porous prill nitrate and has water resistance can be used. Two or more types are used in combination. 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 the above, acrylic resins, styrene / butadiene resins, polyurethane resins, styrene / butadiene copolymer rubbers, and acrylonitrile / butadiene copolymer rubbers are preferred. These can be provided for coating as an emulsion. The coating of the porous prill nitrate with the polymer is carried out by adding a predetermined amount of the polymer to the porous prill nitrate, stirring (when the polymer is solid at room temperature, adding after heating and melting), and mixing. In the case of coating with a polymer that has been heated and melted, porous prill nitrate coated with a solid polymer can be obtained by cooling to room temperature.

[0015] The amount of the polymer used for coating the porous prill nitrate is usually 2.
It is 5 to 70.0% by weight, preferably 7.0 to 50.0% by weight. In addition, in the explosive composition of the present invention using fuel oil, a method of first mixing porous prill nitrate and fuel oil and then coating with a coating polymer can be adopted. In this case, the amount of the polymer used is in the range of 2.5 to 50.0% by weight, preferably 7.0 to 40.0% by weight based on the mixture of porous prill nitrate and fuel oil.

The explosive composition of the present invention can be subjected to measures for preventing static electricity, 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 generally prepared by mixing and mixing a porous prill nitrate and a polymer with a mixer such as a kneader or a high-speed mixer to obtain a porous prill nitrate coated with a solid polymer, If necessary, it is produced by mixing fuel oil or the above-mentioned additives.

The explosive composition of the present invention can be used in bulk, has fluidity, etc., like conventional ANFO explosives.
It is excellent in handleability and can be used without removing water present in the perforation and intruding water.

[0019]

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” indicates “parts by weight”.

Example 1 67.1 parts of porous prill nitrate having an oil absorption of about 12.5%, a hardness of 12.0%, and an average particle diameter of 1.2 mm were mixed with 97.1 parts of
Microcrystalline wax melted at 120 ° C. (Himic 2065) was placed in a container of a high-speed mixer heated to 0 ° C., and stirred at a speed of 150 rotations per minute.
4.3 parts of Nippon Seisaku Co., Ltd.) were added, and the polyurethane was melted at 130 ° C. (Pearlthane U-1).
28.6 parts (00A manufactured by Nippon Polyurethane Industry Co., Ltd.) were added to obtain 100 parts of the explosive composition of the present invention.

Example 2 The same porous prill nitrate (67.5 parts) as in Example 1 was added to 60
Polyurethane emulsion having a solid content of 40% by weight (Yukot UX-2505 Sanyo Chemical Industry Co., Ltd.) placed in a horizontal kneader container equipped with sigma blades heated to 100 ° C. and stirred at a speed of 100 revolutions per minute. 3)
2.5 parts were added to obtain 80.5 parts of the explosive composition of the present invention. The obtained porous polymer coated porous prill nitrate was cleaved to obtain a digital microscope VH-630.
Observation of the cross section at 0 (manufactured by KEYENCE) confirmed that porous prill ammonium nitrate was coated with the solid polymer.

Example 3 The same porous prill ammonium nitrate (70.6 parts) as in Example 1 was added to 90
Into a high-speed mixer vessel heated to
While stirring at a speed of 00 rotation, 29.4 parts of the polyurethane described in Example 1 melted at 130 ° C. was added to obtain 100 parts of the explosive composition of the present invention.

Example 4 The same porous prill nitrate (67.1 parts) as in Example 1 was added to 90
Into a horizontal kneader equipped with a sigma wing heated to 120 ° C. while stirring at a speed of 80 revolutions per minute.
4.3 parts of the microcrystalline wax described in Example 1 which was melted at a temperature of ° C. was added to obtain a granular explosive composition. This was placed in a container of a high-speed mixer heated to 50 ° C., and agitated at a speed of 150 revolutions per minute, while a latex of styrene / butadiene copolymer rubber having a solid component of 50% by weight (JSR0569 JSR Corporation) 28.6 parts) to obtain 85.7 parts of the explosive composition of the present invention.

Comparative Example 1 94.0 parts of the same porous prill nitrate as in Example 1 were placed in a container of a horizontal kneader equipped with sigma wings, and 80 parts per minute.
While stirring at the speed of rotation, 6.0 parts of No. 2 light oil was added to obtain 100 parts of a comparative explosive composition. Evaluation test (1) Water resistance test 300 g of each explosive composition obtained in Examples 1 to 4 and Comparative Example 1 was poured into a transparent acrylic tube having an inner diameter of 50 mm to be immersed therein, and their floating state was observed. An evaluation was performed.

(2) Fluidity test Each of the explosive compositions obtained in Examples 1 to 4 and Comparative Example 1 was directly poured into a PVC pipe having an inner diameter of 60 mm and a length of 1 m, and the fluidity was observed and evaluated.

The results are shown in Table 1.

Table 1 Table 1 Evaluation Test Results Example 1 Example 2 Example 3 Water resistance (after 1 hour) About 14% of the whole explosive composition of the whole explosive composition float about 12% of the whole explosive composition Floating About 15% is floating (after 3 hours) About 40% of the whole explosive composition is about 37% is floating About 45% is about 45% is floating Good Good Good Example 4 Comparison Example 1 Water resistance (after 1 hour) Approximately 10% of the entire explosive composition is suspended 100% is suspended / dissolved (after 3 hours)-About 33% of the entire explosive composition is suspended Fluid Good Good

Since the explosive composition of Comparative Example 1, which is a conventional ANFO explosive, does not have water resistance, porous prill nitrate dissolves instantaneously and No. 2 light oil floats on the water surface. On the other hand, the explosive composition of the present invention obtained in Examples 1 to 4 does not immediately dissolve the porous prill nitrate even when poured into water. It is clear that about 90% do not dissolve and float, and have superior water resistance compared to conventional ANFO explosives. It is also evident that it has the same fluidity as conventional ANFO explosives and can be directly poured and loaded.

[0029]

According to the present invention, an explosive composition having water resistance and having the same handling property as that of a conventional ANFO explosive was obtained.

Claims (5)

[Claims] 1. A water-resistant granular explosive composition comprising a porous prill ammonium nitrate coated with a solid polymer. 2. A water-resistant granular explosive composition comprising a porous prill ammonium nitrate coated with a solid polymer and a fuel oil. 3. The water-resistant granular explosive composition according to claim 1, wherein the coating amount of the solid polymer to the porous prill ammonium nitrate is 2.5 to 70.0% by weight. 4. The water-resistant granular explosive composition according to claim 1, wherein the form of the polymer in the coating step is a molten liquid or an emulsion. 5. The solid polymer is an acrylic resin, a styrene / butadiene resin, a polyurethane resin, a styrene / butadiene copolymer rubber, an acrylonitrile / butadiene copolymer rubber, or a mixture thereof. 5. The water-resistant granular explosive composition according to any one of 4.