JPH049756B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a water-in-oil emulsion explosive, which is characterized by using specific additives and specific microscopic hollow spheres, and mixing the additives at a specific time. This invention relates to a method for producing a water-in-oil emulsion explosive, which hardens the substance and greatly improves handling properties without impairing the stability over time of detonation sensitivity at a diameter of 25 mm. Conventionally, an oxidizing agent aqueous solution containing ammonium nitrate as a main component and a combustible mixture consisting of oils and an emulsifier are emulsified and mixed, and micro hollow spheres are added to the obtained water-in-oil emulsion (hereinafter referred to as W/O emulsion). A common method for producing water-in-oil emulsion explosives (hereinafter referred to as W/O emulsion explosives) was to mix them. In addition, the micro hollow spheres used are alkaline or weakly alkaline micro hollow spheres such as glass,
They are neutral or weakly acidic microscopic hollow spheres such as silica, pitch, and synthetic resin. When alkaline or weakly alkaline micro hollow spheres are used, there is a manufacturing problem in that a large amount of glass components are eluted during mixing, and ammonia gas is generated by reaction with ammonium nitrate or the like. In addition, there was a problem that the balance of the W/O emulsion was disrupted by the eluted components, resulting in the resulting W/O emulsion explosive becoming soft and difficult to handle. In addition, in the case of neutral or weakly acidic micro hollow spheres, the destruction of the W/O type emulsion due to shear stress also causes the explosive to become soft, making it difficult to handle, and furthermore, detonation in small diameter (25 mm diameter) There was also the problem of poor sensitivity stability over time. Furthermore, for the purpose of improving stability over time, a production method is also known in which the additives specified in the present invention are blended in advance into an oxidizing agent aqueous solution, and microscopic hollow spheres are mixed into the resulting W/O emulsion ( U.S. Pat. No. 3,715,247, U.S. Pat. No. 3,765,964, JP-A-57-42592, and JP-A-57-47791). However, this method takes time to form a W/O type emulsion, and the resulting W/O emulsion
There was a problem that the O-type emulsion explosive had a soft chemical quality and was difficult to handle. Furthermore, in order to harden the medicinal quality of the W/O emulsion explosive, it is also possible to use oils with high viscosity (high melting point or high softening point) or a large amount of emulsifier as a combustible agent. However, it is difficult to form a W/O type emulsion in a short period of time, which makes continuous production difficult, and there are also problems in that the stability over time of detonation sensitivity at small diameters is poor. If the W/O type emulsion explosive has a soft quality, it deforms during transportation, making it difficult to load during blasting, resulting in poor blasting effectiveness and, in extreme cases, causing unexploded residue. In addition, if the drug substance is soft, the dispersed phase consisting of the oxidizing agent aqueous solution tends to coalesce over time and other external factors, resulting in performance problems such as deterioration of the stability over time of detonation sensitivity, especially for small-diameter explosives. Ta. Therefore, as a result of intensive research over a long period of time in order to solve all of the conventional problems mentioned above, the inventors of the present invention used a combination of a specific additive and a specific hollow micro sphere, and mixed the additive at a specific time. By doing so, the present invention was completed based on the knowledge that it is possible to improve manufacturability and harden the medicinal substance without impairing the stability over time of detonation sensitivity in small diameters. That is, the present invention provides a W/O emulsion obtained by emulsifying and mixing an oxidizing agent aqueous solution containing ammonium nitrate as a main component and a combustible mixture consisting of an emulsifier and an oil having a melting point or softening point of 20° C. or higher. , mixing specific additives and specific hollow micro spheres W/
This is a method for producing an O-type emulsion explosive. Here, the specific additives include borates, acetates, citrates, polyacrylates, and L-glutamic acid of ammonium, alkali metals, alkaline earth metals, or metals in which a portion thereof is replaced with hydrogen. Salt powders or aqueous solutions, such as borates of ammonium, lithium, sodium, potassium, copper, beryllium, magnesium, calcium, bad lead, strontium, barium, and metals in which some of these are replaced with hydrogen, acetic acid. salts, citrate, polyacrylate and L-glutamate,
Powder or aqueous solution of naphthalene sulfonate and chloride. In the present invention, these additives are used singly or as a mixture of two or more, and their blending ratio is 0.005 to 7% by weight, preferably 0.01 to 5% by weight, based on the total weight of the W/O emulsion explosive composition. The blending ratio is
If it is less than 0.005% by weight, the effect of the present invention will be small;
If it exceeds 7% by weight, it is disadvantageous in terms of reduced potency and raw material costs. The concentration of these additives in an aqueous solution is not particularly limited, and they do not need to be completely dissolved, but may be a suspension. However, from the standpoint of the power of W/O emulsion explosives, it is better to use a smaller amount of water. Further, the specific micro hollow spheres are neutral or weakly acidic micro hollow spheres, such as inorganic micro hollow spheres such as shirasu, volcanic rock, alumina, nacre, obsidian, shale, and flyash, such as pitch, Carbonaceous microscopic hollow spheres such as coal and phenol microballoon calcined products, and synthetic resin microscopic hollow spheres such as vinylidene chloride-acrylonitrile-methyl methacrylate terpolymer, phenolic resin, epoxy resin, and urea resin. . These microscopic hollow spheres are used alone or as a mixture of two or more. The blending ratio thereof is approximately 1 to 10% by weight based on the total amount of the W/O emulsion explosive composition. Further, in the present invention, the specific additive is added after the W/O emulsion is formed, and
If it is added to the oxidizing agent aqueous solution in advance, it takes time to form a W/O emulsion, and furthermore, the medicinal quality of the resulting W/O emulsion explosive cannot be improved. The method for producing the W/O type emulsion explosive of the present invention can be employed in either a batch type or a continuous type, and the present invention will be explained in more detail below using an example of a batch type. First, an oxidizing agent containing ammonium nitrate as a main component is dissolved in water at about 70 to 100°C to obtain an oxidizing agent aqueous solution. Here, the oxidizing agent whose main component is ammonium nitrate means that other oxidizing agents other than ammonium nitrate, such as nitrates, chlorates, perchlorates, etc., can be used together with ammonium nitrate, if necessary. The blending ratio of the oxidizing agent whose main component is ammonium nitrate is usually about 46 to 95% by weight. On the other hand, oils having a melting point or softening point of 20°C or higher and an emulsifier are melt-mixed at about 70 to 100°C to obtain a combustible mixture. The emulsifier used here is an emulsifier conventionally used in W/O emulsion explosives. Next, put the combustible mixture into a heat-retainable container with a certain capacity, gradually add the oxidizing agent aqueous solution, and mix and stir with a regular stirrer until about 70%
Form a W/O type emulsion at 100°C.
After forming the W/O emulsion, it is preferable to continue stirring for several more minutes in order to make the emulsion finer. Next, a predetermined amount of the specific additive specified in the present invention in the form of powder or aqueous solution is added to the above-mentioned W/O emulsion and mixed using a conventional mixer. Next, specific hollow micro spheres defined in the present invention are added and mixed to obtain a W/O emulsion explosive composition. Note that the micro hollow spheres may be added at the same time as the specific additive. The W/O emulsion explosive composition produced as described above is packaged by a conventional packaging method and used as an explosive. Next, the method for producing the W/O type emulsion explosive of the present invention will be specifically explained with reference to Examples and Comparative Examples. Note that all parts in each example are based on weight. Example 1 A W/O emulsion explosive having the composition shown in Table 1 was produced as follows. First, 75.20 parts of ammonium nitrate, 4.51 parts of sodium nitrate, and 10.89 parts of water were added and dissolved by heating to obtain an oxidizing agent aqueous solution at about 90°C. On the other hand, microcrystal wax (mp68.3℃)
3.36 parts of sorbitan monooleate and 1.73 parts of sorbitan monooleate were melted by heating to obtain a combustible agent mixture at about 90°C. Next, put the oxidizing agent aqueous solution and combustible agent mixture in a heat-insulating container, mix and stir at approximately 1600 revolutions/minute using a propeller blade stirrer, and after 2 minutes and 40 seconds, a W/O emulsion is formed. It was done. After that, 5
Continuing stirring for micronization for about 85℃ W/O
A mold emulsion was obtained. After that, 20% sodium tetraborate aqueous solution 2
By mixing 4.31 parts of neutral or weakly acidic micro hollow spheres ("Silica Balloon SPW-7" manufactured by Kushiro Coal Dry Distilling Co., Ltd.) consisting of silica and shirasu into the above W/O type emulsion using a mixing machine, W /O type emulsion explosive was obtained. This W/O type emulsion explosive composition was molded to have a diameter of 25 mm and a dosage of 100 g, and was packaged in viscose-treated paper and subjected to various performance tests. Performance tests include (a) provisional specific gravity (g/cc) one day after manufacture and (b) penetration hardness (mm).
(Depth of penetration (mm) when an iron cone (inclination angle 30°C) is dropped from a height of 45 mm) (c) Measurement of the sample cartridge.
After repeating the temperature cycle of keeping it at 60℃ for 24 hours and then keeping it at -15℃ for 24 hours, a detonation test was performed at -5℃ using a No. 6 detonator to determine the temperature cycle that would result in a complete explosion. Determine the number of cycles and estimate the number of times as the number of months of storage for complete detonation when stored at room temperature (10 to 30℃) (Estimated based on experimental confirmation that the above temperature cycle corresponds to approximately one month when stored at room temperature) A detonation sensitivity stability test over time was conducted. The first result of each of the above
Shown in the table. Examples 2-3 In place of the 20% sodium tetraborate aqueous solution, the first
A water-in-oil emulsion explosive was produced in accordance with Example 1, except that the prescribed amounts of each of the additives shown in the table were used. Performance tests were conducted on the same items as medicine packages and pears. The results are shown in Table 1. Example 4 After obtaining a W/O type emulsion in the same manner as in Example 1, carbonaceous microscopic hollow spheres ("Crecas Sphere A200" manufactured by Kureha Chemical Industry Co., Ltd.) were used in place of silica microscopic hollow spheres. A W/O type emulsion explosive was produced according to Example 1 except that 10% calcium acetate aqueous solution was used in place of the % sodium tetraborate aqueous solution, and the formation time of the W/O type emulsion was examined. Performance tests were conducted on the same items as medicine packages and pouches using the same method. The results are shown in Table 1. Example 5 After obtaining a W/O emulsion in the same manner as in Example 1, 20% tetraboron was added to vinylidene chloride micro hollow spheres (“Expancel” manufactured by Kemanode) instead of silica micro hollow spheres. A W/O type emulsion explosive was produced according to Example 1, except that a 10% ammonium citrate aqueous solution was used in place of the sodium citrate aqueous solution, and the formation time of the W/O type emulsion was determined using the same method as in Example 1. Performance tests were conducted on the same items as medicine packages and pears. The results are shown in Table 1.

[Table] Comparative Example 1 A W/O emulsion explosive having the composition shown in Comparative Example 1 in Table 2 was produced as follows. First, add 75.20 parts of ammonium nitrate, 4.51 parts of sodium nitrate, and 0.25 parts of sodium tetraborate to water.
Add 10.89 parts and dissolve by heating to approx.
An aqueous oxidizing agent solution at 90°C was obtained. On the other hand, 3.36 parts of microcrystan wax (68.3°C) and 1.73 parts of sorbitan monooleate were melted by heating to obtain a combustible mixture at about 90°C. Next, first put the oxidizing agent aqueous solution and the combustible mixture into a heat-insulating container, mix and stir at approximately 1600 revolutions/minute using a commonly used propeller blade stirrer, and after 4 minutes and 50 seconds, W/ An O-type emulsion was formed. Thereafter, stirring for micronization was continued for 5 minutes to obtain a W/O emulsion at about 85°C. Finally, by mixing 4.06 parts of silica micro hollow spheres into the W/O emulsion using a mixer,
A W/O type emulsion explosive was obtained. A performance test was conducted using the same method as in Example 1, using a medicine package and the same items. The results are shown in Table 2. Comparative Examples 2 to 5 W/O emulsion explosives were produced in accordance with Comparative Example 1, except that the additives shown in Table 2 were used in place of sodium tetraborate in Comparative Example 1, and W/O emulsions were formed. The time was checked, and a performance test was conducted using the same method as in Example 1 for the same items as medicine packages. The results are shown in Table 2. Comparative Examples 6 to 10 Comparative Example 1 without sodium tetraborate (Comparative Example 6), microcrystalline wax (mp68.3℃) of Comparative Example 6 replaced with microcrystalline wax (mp82.2 °C) (Comparative Example 7), microcrystalline wax (mp68.3°C) replaced with paraffin wax (mp71.1°C) (Comparative Example 8), and silica micro hollow spheres replaced. The weight ratio of the microcrystalline wax (mp68.3℃) and sorbitan monooleate in Comparative Example 9 and Comparative Example 6, which were replaced with glass micro hollow spheres ("Glass Bubbles B15/250" manufactured by 3M), was W/O emulsion explosives were produced in accordance with Comparative Example 1, with the ratio changed from about 2:1 to about 3:1 (Comparative Example 10), and the W/O emulsion formation time was investigated. Performance tests were conducted using the same method as in 1 for the same items as medicine packages. The results are shown in Table 2. Comparative Examples 14 to 17 W/O emulsion explosives were produced according to Comparative Example 1 with the composition shown in Table 2, respectively.
The formation time of the W/O type emulsion was investigated, and the performance tests for the same items were conducted using the same method as in Example 1 to form a medicine package. The results are shown in Table 2.

【table】

[Table] W/O in which the specific additive of the present invention and specific hollow micro spheres are mixed after forming a W/O emulsion
Method for manufacturing type emulsion explosives (see Table 1)
The formation time of the W/O type emulsion is short, from 2 minutes 30 seconds to 2 minutes 40 seconds, and the storage period for complete detonation based on the results of the detonation sensitivity and stability test over time of the obtained W/O type emulsion explosive is short. Despite being 22 to 24 months old, the hardness (penetration value) of the explosive was 13 to 14 mm, making it easy to handle. Naru W/
The manufacturing method of mixing micro hollow spheres into O-type emulsion (see Table 2) has a long W/O-type emulsion formation time of 2 minutes 35 seconds to 5 minutes 5 seconds, and the resulting W/O-type emulsion explosive The storage period for complete detonation is 13 to 21 months based on the detonation sensitivity and stability test results, but the hardness (penetration value) of the explosive is 19 months.
It was soft at ~21 mm and had extremely poor handling properties.
In addition, in a composition in which the ratio of oil to emulsifier was changed to about 3:1 (Comparative Example 10), the penetration was 13 mm, which was hard.
The formation time of the W/O type emulsion was as long as 4'50'', and the storage period for complete detonation based on the results of the detonation sensitivity and stability test over time was extremely poor at 7 months. A method for producing a W/O emulsion explosive characterized by mixing a specific additive and specific hollow microspheres after forming a W/O emulsion is a method for producing a W/O emulsion explosive, which is characterized by mixing a specific additive with an oxidizing agent aqueous solution. Compared to a production method in which micro hollow spheres are mixed into a W/O emulsion obtained by mixing or not blending, the productivity of W/O emulsion explosives is improved, as well as the detonation sensitivity at a small diameter (25 mm diameter). It is clear that handling properties are greatly improved by hardening the medicinal substance without compromising its stability over time. The manufacturing method of mixing makes W/O emulsion explosives easier to manufacture than the conventional manufacturing method, and it is easier to handle because the substance becomes harder without compromising the stability over time of detonation sensitivity in small diameters (25 mm diameter). The improvement can be considered as follows: That is, the manufacturing method in which a specific additive and specific hollow micro spheres are mixed into a W/O emulsion obtained without adding the specific additive to the oxidizing agent aqueous solution is as follows. W/
A W/O type emulsion that is easily emulsified and has a stable form is provided because the specific additives that disrupt the balance of the O type emulsion are not dissolved in the oxidizing agent aqueous solution. Therefore, when certain additives are mixed with it, appropriate amounts of these additives are dissolved and the W/O type emulsion is destroyed only in the vicinity of the micro hollow spheres, so that physical destruction due to shear stress does not spread to the whole. Therefore, the obtained W/O type emulsion explosive had significantly improved handling properties due to the hardness of the drug, without impairing the stability over time of the detonation sensitivity at a small diameter (25 mm).

Claims (1)

[Claims] 1. Add ammonium, alkali metals, Powder or aqueous solution of borates, acetates, citrates, polyacrylates, and L-glutamates of alkaline earth metals or metals in which some of them are replaced with hydrogen, and neutral or weakly acidic microorganisms. A method for producing a water-in-oil emulsion explosive characterized by mixing with hollow spheres.