RU2449976C1 - Method of changing crystal shape of explosive substance - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of explosives and can be used in explosive devices which employ the process of transforming combustion of an explosive into an explosion. The method involves obtaining a saturated solution of an explosive in an organic solvent using a method for mixing with a liquid precipitant, precipitation of crystals of the explosive substance by adding the liquid precipitant to a suspension of the undissolved substance in its saturated solution, followed by filtration of the obtained suspension, drying and granulation. The precipitant used is water, wherein the ratio of the water volume to the volume of the solution is equal to (3-5):1. For octogene and ten, the organic solvent used is acetone and for hexanitrostilbene, the organic solvent used is dimethyl formamide.

EFFECT: method enables to change the original shape of crystals of an explosive and obtain a powdered explosive consisting of a mixture of crystals of different shape (prism, lamellar, needle-like, rectangular) and different fractional composition (a fraction with mean particle size of 300 mcm and a fraction with mean particle size of 20 mcm), which enables to optimise conditions for transient processes during detonation in an explosive charge; method is safe and easy to implement.

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Description

The invention relates to techniques and technology for explosives (BB) and can be used in detonators and other explosive devices that use the process of transferring the combustion of an explosive into an explosion.

The well-known "Method of producing highly dispersed octanite" according to the patent of the Russian Federation No. 2281931, C06B 21/00, publ. BI No. 23, 2006

The method is based on obtaining a solution of octanite in dimethylformamide, followed by precipitation of octanite and filtering the resulting suspension. To obtain highly dispersed octanite, dimethylformamide is used, and octanite is dissolved at a temperature of 125-135 ° C, and sequential addition of acetone and water are used to precipitate octanite. In this case, the precipitation of octanite from the solution is carried out in two stages.

The starting octanite powder has cubic crystals with an average particle size of less than 100 microns. This method allows to obtain octanite with an average particle size of the order of 1 μm, which is also not optimal for the transition from combustion to explosion.

By technical nature and the problem to be solved, the closest to the claimed method is a method for producing spherical crystalline particles of cyclotrimethylene trinitramine from faceted crystals: US patent No. 4065529, C06B 21/00, published December 27, 1977.

The method for producing spherical cyclotrimethylene trinitramine particles from crystals involves three stages: mixing cyclotrimethylene trinitramine crystals having a size of ≥70 μm in a saturated solution of cyclohexanone at an initial temperature; heating the resulting solution and subsequent separation of the crystals from the heated solution.

Using this method, it is possible to obtain spherical particles from crystals with a logarithmic distribution of fractions by diameter. However, this distribution is not optimal for transients. The disadvantage of this method is the use of toxic solvents.

The objective of the present invention is to increase the sensitivity of the explosive due to the presence of different shapes and sizes of crystals in one explosive while improving the safety of the manufacturing method.

Using the proposed method provides the following technical result:

- Obtaining explosive powder, consisting of a mixture of different crystals, allows you to optimize the conditions of the transient processes during the formation of detonation in the explosive charge; this is especially true for mixed explosives, one of the components of which is an ultrafine metal powder, in particular aluminum nanopowder.

- Ensuring process safety by the fact that the technology does not contain operations of intense mechanical action on explosives, nor does it use toxic solvents heated to temperatures close to their boiling point.

To achieve the specified technical result, a method for changing the shape of explosive crystals is proposed, which consists in obtaining a saturated explosive solution in an organic solvent capable of mixing with a liquid precipitant, precipitating explosive crystals by adding a precipitating liquid to a suspension of insoluble matter in its saturated solution, followed by filtering the resulting suspensions in which according to the invention, water is used as a precipitant. The ratio of precipitant to the solution of explosives (3-5): 1.

For octogen and ten, acetone is used as an organic solvent, and dimethylformamide is used as an organic solvent for hexanitrostilbene.

Upon receipt of the solution in an organic solvent, the amount of explosives is dosed in a clear excess, about 2 times the amount capable of passing into the solution at this temperature. In the process of mixing, a change in the shape of the particles of insoluble explosives occurs. Part of the initial explosive dissolves, the concentration of the solution increases, and when the saturation point is reached, part of the crystals cannot dissolve and precipitates at the bottom of the tank. When a precipitating liquid is added to the solution (for example, for an acetone solution of water or alcohol), explosive crystals precipitate. After that, the resulting explosive is separated from the liquid phase (solvent and precipitant) by filtration, followed by drying and granulation.

The resulting powder consists of fractions that differ sharply in size and shape. Explosive tests of detonators show that the length of the transition section is minimal when initiating detonation in a charge based on such an explosive.

List of figures

Figure 1 shows large crystals of the original explosive.

Figure 2 shows a mixture of crystals of explosives of various shapes and sizes after deposition (large insoluble crystals and small crystals obtained by deposition) and a metal nanopowder.

The proposed method is as follows.

Example 1

870 g of a saturated solution of HMX in acetone are obtained by stirring for 30 minutes at room temperature. Then add 2700 g of distilled water at a temperature of 21 ° C. After draining the water, the precipitate is filtered on a vacuum filter, dried at 75 ° C under vacuum.

The initial crystals of HMX have an almost cubic shape and rounded corners, the size of the crystals from 200 microns or more. The result is HMX powder, which contains small crystals having a prismatic shape, crystals with a scaly shape and large crystals of an indefinite shape.

Example 2

870 g of a saturated solution of HMX in acetone are obtained by stirring at a speed of 150 rpm for 30 minutes at room temperature. Then, without turning off the stirrer, add 5.0 g of ultrafine aluminum and distilled water in an amount of 3 liters at a temperature of 23 ° C. After draining the water, stir another 2 minutes. The mixer is stopped, the precipitate is poured into a container, after which the precipitate is filtered on a vacuum filter, dried at 75 ° C under vacuum.

The result is an HMX powder, which consists of small crystals having a prismatic shape and flake crystals, and large crystals of an indefinite shape, ultrafine aluminum powder covers the surface of the crystals.

Example 3

Obtain 80 g of a saturated solution of ten in acetone by stirring at room temperature. To the resulting solution add 300 g of distilled water at a temperature of 22 ° C and mix. The precipitate was filtered on a vacuum filter, granulated and dried at 75 ° C.

The initial crystals of PETN have a rectangular shape, crystal sizes from 150 microns or more. As a result of disembarkation, a finely dispersed PETN powder is obtained, which includes crystals having a needle shape and large crystals of irregular shape.

Example 4

100 g of a saturated solution of hexanitrostilbene in dimethylformamide are obtained by stirring at room temperature. Then add 300 g of distilled water at a temperature of 22 ° C and mix. The precipitate was filtered on a vacuum filter, granulated and dried at 75 ° C.

The initial crystals of hexanitrostilbene have a rectangular shape, crystal sizes from 200 microns or more. As a result of planting, hexanitrostilbene powder is obtained, which includes crystals having a needle shape (needle sizes 1 μm or less) and large crystals of irregular shape.

Claims (2)

1. The method of changing the shape of crystals of explosives, which consists in obtaining a solution of explosives (BB) in an organic solvent, the precipitation of crystals of explosives using water as a precipitant, followed by filtration and drying, characterized in that before precipitation receive a suspension of large particles in a saturated solution ten, or octogen, or hexanitrostilbene in an organic solvent, the amount of precipitant to the BB solution is (3-5): 1, while acetone is used as a solvent for ten and octogen N, and for Hexanitrostilbene - dimethylformamide. 2. The method according to claim 1, characterized in that the water temperature is 21-23 ° C.

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