RU2432347C2 - Extrusion-emulsion method to produce coarse pellet powders - Google Patents

Abstract

FIELD: explosives.

SUBSTANCE: method is proposed to produce coarse pellet powders, including preparation of a powder mass made of 1 wt part of pyroxylin 1 Pl, 0.7…1.1 wt parts of a volatile dissolvent, 0.1…0.43 wt parts of a crystalline filler, 0.01 wt parts of a chemical resistance stabiliser, for 60…90 minutes. Then, using the extrusion method, powder cords are made with diameter from 1.0 to 4.0 mm, after preliminary dry-curing they are cut into strictly specified sizes, where the diameter corresponds to the length of a powder particle, afterwards the produced semi-finished product is supplied into a reactor, where, using the emulsion method, particles are given the spherical shape while treating 1 wt part of the semi-finished product in 3…4 wt parts of water and 2…3 wt parts of the volatile dissolvent with content of 0.7…1.5 wt % of the protective colloid in water, 2.0…3.5 wt % of sodium sulfate.

EFFECT: method ensures production of powder elements, which are monodisperse in diameter, with adjustment of their dimensions for each brand in the range from 1,0 to 4,0 mm, with high apparent density and low porosity.

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Description

The invention relates to the field of production of spherical powders for heavy machine guns and 30 mm aircraft guns.

US patents [1, 2] propose a method for producing spherical gunpowder for small arms, which consists in grinding fine-grained pyroxylin gunpowders (MZPP) in an aqueous medium, followed by dissolving them in a solvent, dispersing the powder varnish onto spherical particles and removing the solvent from them.

The disadvantage of these methods is the inability to obtain large spherical powders.

The closest technical solution is a method for producing spherical gunpowder for hunting weapons [3] (prototype), including the preparation of powder varnish with stirring of pyroxylin 1 Pl or pyroxylin 1 Pl with return-technological waste (WTO) for 10 ... 15 minutes in 4 ... 5 parts by weight water together with diphenylamine (DFA) in an amount of 0.6 ... 1.2 wt.% and carbon black in an amount of 0.3 ... 1.0 wt.%, coming in the form of an aqueous suspension with a concentration of 20 ... 30 wt.%, and copper (II) -lead (II) phthalate oxide (PMS) in an amount of 0.5 ... 2.5 wt.% by weight of pyroxylin 1 Pl and with 2.4 ... 3.6 wt.h. ethyl acetate (EA), adding bone glue to the varnish, dispersing the powder varnish on spherical particles and removing EA when the mixture is heated to 92 ... 94 ° C.

The disadvantage of this method is that the obtained spherical powder has a size of powder particles with a diameter of not more than 0.63 mm The obtained particles according to this method with a diameter of more than 0.63 mm have an irregular shape.

The objective of the invention is to obtain large spherical powders monodisperse in diameter of the powder elements with the regulation of their sizes for each brand in the range from 1.0 to 4.0 mm

The technical result is achieved by the fact that initially a powder mass is prepared in the mixer, consisting of 1 mass part of pyroxylin 1 Pl, 0.7 ... 1.1 mass parts of volatile solvent, 0.1 ... 0.43 mass parts of crystalline filler and 0.01 mass parts of the stabilizer of chemical resistance for 60 ... 90 minutes, then the powder cords with a diameter of 1.0 to 4.0 mm are prepared by extrusion, after preliminary wiring, they are cut into strictly specified dimensions, where the diameter corresponds to the length of the powder particle, after which the resulting semi-finished product t is fed to the reactor, where the emulsion method gives the particles a spherical shape, processing of 1 mass part of the semi-finished product is carried out in 3 ... 4 mass parts of water and 2 ... 3 mass parts of volatile solvent with 0.7 ... 1.5 wt.% protective colloid in water and 2.0 ... 3.5 wt.% sodium sulfate, the removal of volatile solvent from the powder particles is carried out in a known manner.

Examples of the method for producing large spherical powders, monodisperse in diameter of the powder elements within the boundary conditions (example 1, 2, 3) and outside the boundary conditions (example 4, 5), where for each brand of gunpowder it is possible to control the sizes of the powder elements in the range from 1.0 to 4.0 mm are shown in the table.

Example 1. In a stirrer of 15 liters load 4.5 kg of pyroxylin 1 Pl, 3.15 liters of alcohol-ether solvent, 0.45 kg of RDX or HMX and 0.05 kg of diphenylamine (DPA), and stirring is carried out for 60 minutes. The resulting powder mass is loaded into a hydraulic press mold and the mass is extruded through dies with a diameter of 1.0 mm to obtain powder cords. The obtained powder cords after extrusion are pre-dried for 10 ... 15 minutes and fed to the San Galli machine for cutting, cutting to cylinders 1 mm in length is carried out, the removal of volatile solvent from the powder particles is carried out in a known manner.

The resulting semi-finished product is sent to a 45-liter reactor, where the particles are spherically shaped by the emulsion method in the hydrodynamic mode. 14.25 liters of water are poured into the reactor, 4.75 kg of semi-finished product are charged, 9.5 liters of ethyl acetate (EA), 0.1 kg of protective colloid and 0.285 kg of sodium sulfate are introduced and mixing is carried out at a temperature of 65 ... 68 ° C for 30 minutes, then distillation of the solvent is carried out in a known manner. The characteristics of gunpowder are given in the table.

Example 2. In a stirrer of 15 liters load 3.95 kg of pyroxylin 1 Pl, 3.55 liters of alcohol-ether solvent, 1.0 kg of RDX or HMX and 0.05 kg of DFA, and stirring is carried out for 60 minutes. The resulting powder mass is loaded into a hydraulic press mold and the mass is extruded through dies with a diameter of 2.25 mm to obtain powder cords. The obtained powder cords after extrusion are pre-sagged for 10 ... 15 minutes and fed to the San Galli machine for cutting, cutting to cylinders 2.25 mm in length is carried out, the removal of volatile solvent from the powder particles is carried out in a known manner.

The resulting semi-finished product is sent to a 45 liter reactor, where the particles are spherically shaped by emulsion. 16.62 liters of water are poured into the reactor, 4.75 kg of semi-finished product are charged, 11.87 liters of EA, 0.182 kg of protective colloid and 0.457 kg of sodium sulfate are introduced and mixing is carried out at a temperature of 65 ... 68 ° C for 30 minutes, then distillation is carried out solvent in a known manner. The characteristics of gunpowder are given in the table.

Example 3. In a stirrer of 15 liters load 3.45 kg of pyroxylin 1 Pl, 3.8 liters of alcohol-ether solvent, 1.5 kg of RDX or HMX and 0.05 kg of DFA, and stirring is carried out for 60 minutes. The resulting powder mass is loaded into a hydraulic press mold and the mass is extruded through die plates with a diameter of 4 mm to obtain powder cords. The obtained powder cords after extrusion are dried for 10 ... 15 minutes and fed to the San Galli machine for cutting, cutting to cylinders 4 mm in length is carried out, the removal of volatile solvent from the powder particles is carried out in a known manner.

The resulting semi-finished product is sent to a 45 liter reactor to give the particles a spherical shape. 19.0 liters of water are poured into the reactor, 4.75 kg of semi-finished product are charged, 14.25 liters of EA, 0.285 kg of protective colloid and 0.665 kg of sodium sulfate are introduced and mixing is carried out at a temperature of 65 ... 68 ° C for 30 minutes, then distillation is carried out solvent in a known manner. The characteristics of gunpowder are given in the table.

Outside the boundary conditions in examples 4, 5, the results obtained are shown in the table.

Table Technological modes of obtaining large spherical powders, monodisperse in diameter of the powder elements No. p / p The name of indicators According to the proposed method one 2 3 four 5 6 7 one Download pyroxylin 1 PL or powder mass, kg 4,5 3.95 3.45 4.75 3.15 2 The amount of alcohol-ether solvent, l 3.15 3,55 3.8 2.0 4.0 3 The amount of RDX or HMX, kg 0.45 1,0 1,5 0.2 1.8 four The amount of diphenylamine, kg 0.05 0.05 0.05 0.05 0.05 5 Mixing time min 60 60 60 60 60 6 Diameter of powder cords, mm 1,0 2.25 4.0 1,0 4.0 7 The load of the semi-finished product in the reactor, kg 4.75 4.75 4.75 4.75 4.75 8 The amount of water in the reactor, l 14.25 16.62 19.0 11.0 22.0 9 The number of EA in the reactor, l 9.5 11.87 14.25 8.0 16,0 10 The amount of protective colloid, kg 0,100 0.182 0.285 0,080 0,300 eleven The amount of sodium sulfate, kg 0.285 0.457 0.665 0.150 0.750 12 Semi-finished product processing time, min thirty thirty thirty thirty thirty 13 Diameter of spherical elements, mm 1,0 2.25 4.0 1,0 4.0 fourteen The yield of the target fraction of gunpowder,% 99 99 98 - - fifteen The bulk density of spherical powder, kg / DM ³ 0,994 0,995 0,996 0.850 0.820 16 Conditional porosity,% 2.0 2.1 2.2 - -

From the above table results it is seen that the obtained large spherical gunpowder according to the method developed by the authors (example 1, 2, 3) provides the yield of the target fraction of gunpowder with a given size from 98 to 99%. The bulk density of spherical powder is in the range from 0.994 to 0.996 g / cm ³ with a uniformly distributed porosity in the powder elements from 2.0 to 2.2%.

Outside the boundary conditions (example 4, 5), large spherical gunpowder practically does not provide a given shape. Therefore, the method developed by the authors provides large spherical powders, monodisperse in diameter of the powder elements, with a high bulk density and low porosity.

Literature

1. US patent No. 2843584.

2. US Patent No. 3378545.

3. RF patent No. 1727375 (С06В 21/00).

Claims (1)

A method of producing large spherical powders, including the preparation of a powder varnish in an aqueous medium, dispersing it onto spherical particles, followed by removal of solvent from them, characterized in that to prepare the powder elements with regulation of their sizes from 1.0 to 4.0 mm powder mass, consisting of 1 wt.h. pyroxylin 1 Pl, 0.7-1.1 wt.h. volatile solvent, 0.1-0.43 wt.h. crystalline filler, 0.01 wt.h. stabilizer of chemical resistance, for 60-90 minutes, then powder cords with a diameter of 1.0 to 4.0 mm are prepared by extrusion, after preliminary wiring, they are cut into strictly specified dimensions, where the diameter corresponds to the length of the powder particle, after which the resulting semi-finished product is fed into a reactor where the emulsion method gives the particles a spherical shape when processing 1 wt.h. prefabricated 3-4 parts by weight water and 2-3 parts by weight volatile solvent when the content of 0.7-1.5 wt.% protective colloid in water, 2.0-3.5 wt.% sodium sulfate.