RU2521637C2 - Water-containing explosive powder - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to water-containing industrial explosives based on a gel-like matrix sensitised with pyroxiline powder. The water-containing explosive powder contains 40.0-65.0 wt % pyroxiline powder or a mixture thereof with ballistite powder, 6.0-15.0 wt % sodium nitrate, 4.0-10.0 wt % organic fuel, 10.0-25.0 wt % water, 0.3-2.0 wt % polyacrylamide and ammonium nitrate - the balance, wherein the linking agent is chrome alum or a mixture of chrome alum and aluminium in powder consistence 0.01-0.1, sodium thiosulphate 0.02-0.2 and further contains aluminium in form of a surface film or foil.

EFFECT: explosive composition widens the range of application conditions and improves the efficiency of charge explosions.

Description

The invention relates to the field of water-containing industrial explosives (PVV) based on a gel-like matrix sensitized with pyroxylin powder.

Water-containing powder PVV, the development of which began abroad in the late 50s of the 20th century, has been widely used in blasting in industry, construction and in emergency situations. The chemical composition of such PVV is developed, researched and described in a number of works and patented in Russia and other countries.

Closest to the proposed invention is a water-containing powder explosive charge, including pyroxylin powder or its mixture with ballistic powder, sodium nitrate, organic fuel, polyacrylamide, as a crosslinking agent is a mixture of potassium dichromate and sodium thiosulfate, ammonium nitrate and water, in which a crosslinking agent used potassium dichromate (RF patent No. 2183209, C06B 25/26, 31/28, publ. 06/10/2002).

During the tests of this PVV, its detonation characteristics, safety and performance characteristics were established. It has been established that in terms of its aggregate characteristics, this composition approaches ideal.

However, in some situations, this composition still has limitations on its use. For example, during blasting operations in underground and cramped conditions, when due to limited space and difficult ventilation in the surrounding atmosphere, high concentrations of environmentally harmful (toxic) hexavalent chromium, which is part of potassium dichromate, are created.

At the same time, for conducting blasting operations in cramped conditions and with a gentle impact on the environment, elongated charges with a small diameter are required, and in the explosion of any charge of explosive without an envelope in air, its critical diameter noticeably increases compared to the passport data.

An object of the invention is to expand the range of conditions of applicability and increase the efficiency of the effects of explosions of charges based on a water-containing powder explosive composition.

The result is achieved in a water-containing powder explosive charge, including pyroxylin powder, sodium nitrate, organic fuel, polyacrylamide, a crosslinking agent, ammonium nitrate and water, due to the fact that it contains chromic acid alum or a mixture of aluminum hydroxide alumina as a crosslinking agent and sodium thiosulfate in the following ratio of components, wt.%:

pyroxylin powder 40.0-65.0 sodium nitrate 6.0-15.0 organic fuel 4.0-10.0 polyacrylamide 0.3-2.0 chromic alum or mixture of chromic alum with aluminum in powder consistency 0.01-0.1 sodium thiosulfate 0.02-0.2 water 10.0-25.0 ammonium nitrate rest.

Moreover, the charge additionally contains aluminum in the form of a surface film or foil.

In the case of using only chromic alum, sodium thiosulfate is not included in the gelpore, i.e. the amount of sodium thiosulfate in the gelpore is proportional to their proportion.

To achieve the first component of the task in the explosive composition, potassium dichromate is replaced by chromic acid alum, which contains environmentally less dangerous divalent chromium, or a mixture of chromic acid alum and aluminum in the consistency of powder in the same weight ratio. This replacement allows for the crosslinking of the components of the composition without loss of safety and performance.

When using potassium dichromate as a crosslinking agent in combination with sodium thiosulfate, the relatively slow structuring of individual molecules into a polymer line occurs. At the same time, Helpor is quite fluid in its rheological properties.

When using chromic alum, structuring of the gelpore occurs much faster, and fluidity increases significantly. These properties were established during the experimental development of gelpore and obviously do not follow from its chemical composition, since it is ultimately a polymer.

For various conditions for the use of gelpore during blasting, various rheological parameters (fluidity) are required. When equipping vertical boreholes with the filling method, gelpores with high fluidity are required, and when equipping horizontal boreholes with cartridge gelpores, low flow is required.

It should be noted that the water-containing powder explosive (WWW) composition (gelpore) is a very complex substance. This is determined by the presence of pyroxylin powder (with a very complex chemical formula) and a gel as an organic polymer.

For this reason, there is still no rigorous equation for the chemical kinetics of detonation processes. The complexity of the chemical composition of gelpore was noted in the work (Dubnov L.V. et al. Industrial explosives. M: Nedra, 1988, p. 259-275). In this regard, the complexity of the composition does not allow the application of strict chemical laws and the main method of creating airborne explosives is the experimental selection of the number of components. A simple replacement of equivalent chemicals in the experiment leads to a failure of detonation, and here the significant factors are the brand of gunpowder, the dispersed composition and the duration of storage.

The second component of the problem is achieved by applying to the surface of the charge a layer of aluminum in the form of a film or foil. Aluminum film performs two functions simultaneously. The first - mechanical - prevents the rapid expansion of the explosion products, which contributes to a more complete reaction of the explosive transformation, i.e. improves efficiency explosion, and reduces the critical diameter of the detonation of the explosives. The second - chemical - leads to an increase in the efficiency of explosive action due to the additional energy released during the oxidation of aluminum in the phase of expansion of the explosion products.

The use of aluminum foil to increase the efficiency of explosive effects was confirmed in the course of special studies (A. Trofimov and others. RF Patent for the application for invention No. 2008128008).

Depending on the specific blasting conditions, the amount of aluminum in the film (foil thickness) is determined by the calculation-experimental method.

The proposed explosive composition is manufactured in laboratory conditions and tested at the enterprise JSC "Plant" TEKON "and FSUE" SKTB "Technologist" (St. Petersburg). The test results confirmed the characteristics of the proposed explosive composition.

Claims (1)

Water-containing powder explosive charge, including pyroxylin powder, sodium nitrate, organic fuel, polyacrylamide, a crosslinking agent, ammonium nitrate and water, characterized in that it contains chromic alum or a mixture of chromic alum with aluminum in a mixture of sodium sulfide as a crosslinking agent the following ratio of components, wt.%:
Pyroxylin powder 40.0-65.0 Sodium Nitrate 6.0-15.0 Organic fuel 4.0-10.0 Water 10.0-25.0 Polyacrylamide 0.3-2.0 Chromium Alum or a mixture of chromic alum with aluminum in powder consistency 0.01-0.1 Sodium thiosulfate 0.02-0.2 Ammonium nitrate rest
and further comprises aluminum in the form of a surface film or foil.