RU2333191C2 - Explosive composition - Google Patents

Abstract

FIELD: explosive works.

SUBSTANCE: invention is related to explosives and may be used in explosive works that are performed with borehole charges in drilled cores. Composition of explosive that contains oxidiser and combustible additive is suggested. In capacity of oxidiser composition contains mixture of dense and porous granulated ammonia nitrate in proportion of 2:1 in the form of polydisperse structure or mixture of dense granulated and powdered ammonia nitrate in proportion of 5:1 in the form of polydisperse structure. In capacity of combustible additive composition contains mixture of liquid oil products and thermal power plant fly ash microspheres in proportion from 6:1 to 3:1. Invention provides high efficiency of explosive composition action at safe level of its sensitivity to mechanical effects.

EFFECT: provision of high efficiency of explosive composition action at safe level of its sensitivity to mechanical effects.

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Description

The invention relates to the field of blasting, and in particular to explosives manufactured near or directly at the site of use, and can be used in blasting with borehole charges in sections.

Known two-component explosive of the simplest type "igdanite" containing 94.5% of dense granular ammonium nitrate (AS) and 5.5% of liquid fuels, for example, diesel fuel or solar oil (B.N. Kutuzov. Blasting operations. - M .: Nedra, 1988, pp. 105-106).

The main disadvantage of the known explosive is a partial loss of explosive properties during prolonged charging due to poor retention of hydrochloric oil by smooth granules of nitrate. In addition, igdanite belongs to explosives of low power and is intended primarily for blasting rocks of weak and medium strength.

Known explosive granulite C-6M, consisting of 64% of granular ammonium nitrate, 6% industrial oil and 30% waterproof powder ammonia nitrate brand ZhV (Chikunov V.I. and others. , 1991, p.24). A specific feature of this explosive is that a granular AS after wetting with hydrochloric oil heated to 80 ° C is dusted with a powdery AS. However, as tests have shown, the stabilization effect is not achieved, the explosive crumbles, coalesces and, when stored, coalesces into a monolith. In addition, the production of this explosive is complicated by the fact that equipment is clogged, especially the pipes through which it is transported.

Known explosive granulite D-5, containing dense granular ammonium nitrate - 94%, diesel fuel - 2% and coal powder - 4% (Safety of coal enterprises. Scientific works. SC VostNII. - Kemerovo, 2001, p.122-124) .

The procedure for producing granulite D-5 involves mixing granular AS and diesel fuel for 10 minutes, followed by the addition of coal powder and mixing the components for another 10 minutes.

The practice of using carbon-containing granulites has shown that in terms of effectiveness they are not suitable for any conditions in terms of the strength of destructible rocks - when blasting large-block rocks, oversized pieces are released that cannot be excavated without additional crushing. Therefore, despite the advantages in economic terms, such granulites need to increase capacity. A common drawback of such granulites is the insufficient homogenization of the oxidizer-fuel mixture due to the traditionally incorrect principle of only retaining the oil on AC granules. Separation of these components does not allow to fully extract the potential energy of the explosion, the potential of the explosive formulation is not fully realized. The main direction of improvement can be considered the combination of two or more combustible components in the composition, which mutually complement each other functionally and act as an energy supplement and sensitizer. The main disadvantages of granulite D-5 should also include the fact that the coal powder used as a solid fuel significantly increases the sensitivity of explosives to mechanical stress and does not ensure the stability of explosive characteristics, since coals of different grades are characterized by a significant dispersion of indicators (ash, moisture, petrographic composition). In addition, coal powder does not have sensitizing properties, which reduces the effectiveness of explosives.

An explosive explosive composition is proposed containing an oxidizing agent based on granular ammonium nitrate and a combustible additive using liquid petroleum products.

The difference of the proposed composition is that as a combustible additive, a mixture of liquid petroleum products and microspheres of fly ash of thermal power plants is used in a ratio of 6: 1 to 3: 1, while the components are taken in the following ratio (wt.%):

granule-based oxidizing agent 92-93 ammonium nitrate a mixture of liquid petroleum products and microspheres of fly ash thermal power plants in a ratio of 6: 1 up to 3: 1 7-8

The oxidizing agent in the composition of this explosive may contain dense and porous granular ammonium nitrate in a ratio of 2: 1 or dense granular and powder ammonium nitrate in a ratio of 5: 1 in the form of a polydisperse structure for uniform distribution of a combustible additive. This technique provides a certain homogenization of the granulite composition in combination with acceptable manufacturability and economic feasibility.

Studies have shown that increasing the power of granulites based on a dense granular AS can be achieved by replacing part of this nitrate with a porous granular AS or with a powder AS filling the intergranular space and being a component holding the oil product. However, in these methods of increasing the power of the explosion, it is necessary to ensure the manufacturability of the composition, its stabilization and the creation of hot spots along the propagation of detonation. The last requirement is satisfied by introducing into the composition of the active additive in the form of microspheres fly ash of thermal power plants. The properties of ash aluminosilicate microspheres are very diverse and, depending on the composition of the coal and the technology for burning it, the microspheres are microspheres from different types of glass shells of a mono- or polycellular structure with a bulk density of 240-360 kg / m ³ . The microspheres of fly ash of thermal power plants are used, for example, for the manufacture of emulsion explosives as an active additive and their parameters are regulated by TU 7276-002-16359200-96. "Aluminosilicate microspheres for explosives."

In the simplest explosive compositions, with an increase in the density of the granules, the number of voids inside each granule decreases, and consequently, the number of flash points also decreases, which leads to a corresponding decrease in the rates of decomposition and detonation. For this reason, explosive mixtures of the AC-DT type, consisting of dense AS granules or a mixture of them with powder AS or porous granular AS, have low detonation ability and, accordingly, low explosion rates. Entering into the simplest explosive of this type of microspheres of fly ash of thermal power plants eliminates these drawbacks, however, this significantly increases the level of sensitivity of the composition to mechanical stresses, which poses a great danger, because mechanization means are used both directly when mixing components, and when loading wells. To maintain the sensitivity of the proposed composition to mechanical stress at a satisfactory level, it is proposed to mix with the fly ash microspheres before mixing with AS with the entire amount of liquid petroleum product (up to 6-7% by weight of the composition), i.e. in the ratio from 6: 1 to 3: 1. Such a mixture provides a decrease in the sensitivity of the composition to mechanical stresses to a safe level, creates conditions for the complete explosive decomposition of explosive components (mixtures of various types of AS) along the entire length of the well and an increase in the detonation speed.

In the composition of the water-based explosive according to Russian patent No. 2055064 (class СО 6 В 31/28, published in 1996, No. 6), oily flotation ash of power plants is used to protect the surface of microspheres from calcium chloride, which negatively affects the speed and completeness of detonation . For this purpose, part of the petroleum products is used (0.3-0.5% of the total weight of the composition) and oiling is carried out in the ratio of liquid petroleum microspheres from 1:10 to 1:12. It should be noted that for a water-based explosive, such an indicator as sensitivity to mechanical stress does not have the same value as for the simplest explosives of the AC-DT type, and, in addition, the input of microspheres oiled in this ratio (1: 10-1: 12) , the proposed composition will not have any impact on this indicator.

Thus, the proposed composition of explosives has the following advantages over the known:

artificial formation of igniter points, contributing to the stability of the detonation mode by introducing fly ash microspheres;

ensuring stability, increasing the density and power of the explosion when replacing part of a dense granular nitrate with a powder or porous speaker;

ensuring a safe level of sensitivity of the composition to mechanical stress;

finer distribution of the components in the explosive composition and sufficient homogenization of the composition (with the required quality of the oil product) due to the use of an increased up to 6% amount of liquid oil product as the combustible part of the explosive and the exclusion of the solid combustible type of coal powder with difficult to control parameters.

The mechanism of action of microspheres in the compositions of emulsion explosives is fairly well explained from the point of view of the hydrodynamic theory of detonation, but the effect of this additive in compositions based on granular AS is not well understood. Here, apparently, there is a cumulative manifestation of the active zones in the form of gas inclusions both in the intergranular space of the AS and in the microspheres.

To determine the physical indicators, sensitivity to mechanical stress and effectiveness of the action, prototypes of granulites were made. The compositions were prepared in two stages, on the basis of the assumption that the sensitivity of the compounds to mechanical stress was reduced due to the passivation of the most dangerous part, the fly ash microspheres of thermal power plants, with oil.

First, these components were mixed with each other, and then with ammonium nitrate.

The influence of the sequence of mixing granulite components on impact sensitivity is shown in table 1.

Table 1
The effect of the order of mixing components on the sensitivity of explosives to mechanical stress No pp Name of components Mass fraction of components,% Component mixing order Sensitivity to shock,% of explosions one Prototype (granulite D-5): Granular ammonium nitrate (AS) 93.0 Mixing all components at the same time 24 Liquid petroleum products (NP) 4.0 Coal Powder (UP) 3.0 2 A mixture of powdered and dense granular speakers 93.0 Mixing all components at the same time twenty Liquid petroleum products (NP) 6.0 Microspheres of fly ash (MS) 1,0 3 A mixture of dense and porous granular speakers 93.0 First NP with MS, and then the resulting mixture with AS fourteen Liquid petroleum products (NP) 6.0 Microspheres of fly ash (MS) 1,0 four A mixture of powdered and dense granular speakers 93.0 First NP with MS, and then the resulting mixture with AS 16 Liquid petroleum products (NP) 6.0 Microspheres of fly ash (MS) 2.0

The results of testing the compositions for impact sensitivity show that preliminary mixing of the oil product with the microsphere, and then with the AC, reduces this figure by 25-30% and reaches the required level according to the technical requirements for explosives of this type.

To establish the optimal granulite composition according to the main operational characteristics, model samples of granulites of various compositions were prepared and tested. The tests were carried out according to an industry methodology widely used in Russia in a channel mortar by blasting charges of 200 g each and recording the effect of the compression of a lead cylinder. Initiation was carried out from an intermediate detonator of ammonite No. 6ZHV weighing 150 g bulk density. The results of individual tests are shown in table 2.

table 2
Test results of granulite model formulations by effectiveness No pp The content of components in the composition, wt.% The amount of compression of the lead cylinder, mm Relative performance indicator one Granulite UP-1 (A), prototype: Dense granular AC ... 93 Diesel fuel -3.5 Coal powder - 3.5 15.7 0.92 2 Dense and porous granular AS in a ratio of 2: 1 ... 93 mixture of liquid petroleum products and microspheres of fly ash in a ratio of 6: 1 ... 7 16.7 0.99 3 Dense and porous granular AS in a ratio of 2: 1 ... 92 mixture of liquid petroleum products and microspheres of fly ash in a ratio of 3: 1 ... 8 17,2 1,02 four Dense granular AS and powder AS in a ratio of 5: 1 ... 93 a mixture of liquid petroleum products and fly ash microspheres in a ratio of 6: 1 ... 7 17.6 1,03 5 Dense granular AS and powder AS in a ratio of 5: 1 ... 92 mixture of liquid petroleum products and microspheres of fly ash in a ratio of 3: 1 ... 8 18.0 1.06

An analysis of the test results shows that the introduction of various types of AS into the composition of explosives in the accepted ratios in the form of a polydisperse structure when using a combustible and activating additive in the form of a mixture of liquid petroleum products and fly ash microspheres improves the stability of the compositions and their effectiveness. The content of the components within the specified limits is optimal. By the heat of explosion, as the most significant indicator in assessing the energy value of explosives, the granulite compositions considered exceed the prototype granulite D-5. By analogy, the TNT equivalent of these compounds is in the same ratio.

According to the results of tests in an industrial environment and taking into account the mechanized preparation and loading of wells in terms of sensitivity to mechanical stress, stability and effectiveness, the composition was approved by the State Technical Supervision Service of Russia for industrial use.

Claims (1)

The composition of the explosive containing ammonium nitrate as an oxidizing agent and a combustible additive, characterized in that as a combustible additive it contains a mixture of liquid petroleum products and microspheres of fly ash of thermal power plants in a ratio of 6: 1 to 3: 1, the oxidizing agent contains a mixture of dense and porous granular ammonium nitrate in a ratio of 2: 1 in the form of a polydisperse structure or a mixture of dense granular and powder ammonium nitrate in a ratio of 5: 1 in the form of a polydisperse structure with the following component content in, wt.%: oxidizer 92-93 a mixture of liquid petroleum products and microspheres fly ash of thermal power plants 7-8