RU2653029C1 - Method for obtaining large-dispersed spherical powder - Google Patents

Abstract

FIELD: weapon.

SUBSTANCE: invention relates to the production of spherical gunpowder for small arms and small caliber artillery. Large-dispersed spherical powder is obtained by preparing a powder varnish, by dispersing it into spherical particles, and then removing the solvent therefrom. Initially, during 60-90 minutes in a mixer, a powder varnish consisting of 70.0-84.0% by weight of 1 Pl pyroxylin is prepared, 15.0-28.8% by weight of the propellant, 1.0-1.2% by weight of the chemical stability stabilizer and solvent-ethyl acetate with the module of 1.5-2.5 (volume) to charge all components. Then the powder varnish is injected with excess pressure into the granulator, where it is cut into the strictly prescribed dimensions of the powder element. Further, the powder elements enter the reactor, where the particles are spherically shaped in the presence of 3-4 wt.% of water with the content of 0.6-1.3% by weight of a protective colloid (leather glue) and 0.6-1.3% by weight of sodium sulfate for 60-90 minutes, after which a volatile solvent is removed from the propellant particles.

EFFECT: method ensures the production of spherical particles with the diameter of up to 4 mm with a high yield of the product.

1 cl, 1 tbl, 5 ex

Description

The invention relates to the field of production of spherical powders (TFP).

Known methods for producing coarse-grained TFP with a diameter of granules up to 3 mm, manufactured by water-dispersion technology [1-4]. According to these methods, various techniques are used to hold large varnish particles in the hydrodynamic field of the apparatus with a stirrer:

- the use of effective thickeners dispersion medium;

- portioned input of the dehydrator combined with the phased removal of the solvent;

- dosage after dispersion of the powder varnish of finely dispersed granules of TFP (0.2-0.8 mm) of a similar composition to remove excess ethyl acetate to prevent droplet coagulation;

- re-dispersion of the powder varnish after stopping the process.

The disadvantages of the methods are polydispersity of granules, low density, low yield.

The closest technical solution (prototype) [5] is a method for producing coarse-grained TFP, including the preparation of powder varnish with stirring of nitrate cellulose ingredients in water with ethyl acetate, dispersion of varnish and removal of solvent, according to which the manufacture of granules is carried out in two stages as follows: preparation of powder varnish is carried out in 6-10 wt. including water in relation to the cellulose nitrate ingredients, an emulsifier is introduced in an amount of 2.0-4.0 wt. % with respect to water, varnish is dispersed and the solvent is removed in an amount of 40-50% of the total filled volume, the contents of the reactor are cooled to 50 ° C, the process is stopped, excess water is decanted in an amount of 3-6 wt. hours, then carry out the formation of granules for 60-180 minutes at a temperature of 50-69 ° C in the presence of 3-6 wt. % emulsifier and 4-10 wt. % sodium sulfate in relation to water and the subsequent removal of the residual amount of solvent.

The disadvantage of this method is the low yield of the product (55-60%) and the inability to obtain granules with a diameter of more than 3 mm by water-dispersion technology.

The aim of the invention is to increase the yield and obtain granules with a diameter of up to 4 mm

This goal is achieved in that the extrusion-dispersion method for producing coarse spherical powders, including the preparation of powder varnish in ethyl acetate (EA) and the removal of solvent, is characterized in that a powder varnish is prepared in the mixer for 60-90 min, consisting of 70.0- 84.0 wt. % pyroxylin 1Pl, 15.0-28.8 wt. % powder mass, 1.0-1.2 wt. % stabilizer of chemical resistance, and EA is taken in a ratio of 1.5-2.5 (volume.) to load all the components, then the powder varnish is fed into a granulator, irrigated with water, where they are cut to a predetermined size of the powder element, then the powder elements enter the reactor where the particles give a spheroidal shape in the presence of 3-4 wt. hours of water, with a content of 0.6-1.3% wt. protective colloid (glue) and 0.6-3.5% wt. sodium sulfate in relation to water for 60-90 minutes

Examples of the method for producing coarse 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) are shown in the table.

Example 1. In the mixer load 84.0 wt. % pyroxylin 1Pl, 15.0 wt. % powder mass. The solvent is added based on the loading of the components: module 1: 1.5 (volume.) The chemical stability stabilizer diphenylamine (DFA) in an amount of 1.0 wt. % with respect to 1Pl is introduced with a solvent, and the mass is mixed for 90 minutes. The resulting powder varnish is pumped under pressure from the irrigated water into a granulator where, squeezed through a die of a granulator with a diameter of 4 mm, it is cut into geometrical powder elements (PE). Next, PE enter the reactor with a content of 3.0 wt. including water, 1.3% wt. glue to give a spheroidal shape and the further removal of water from PE by adding 3.0 wt. % sodium sulfate and distillation of ethyl acetate in a known manner. The characteristics of the obtained powder are shown in the table.

Example 2. In the mixer load 78.9 wt. % pyroxylin 1PL, 20.0 wt. % powder mass. The solvent is added based on the loading of the components: module 1: 2.0 (volume.). The stabilizer chemical resistance of DFA in the amount of 1.1 wt. % with respect to pyroxylin 1Pl is introduced with a solvent, and the mass is mixed for 70 minutes. The resulting powder varnish under pressure from irrigated water is pumped into the granulator where, squeezed through the nozzles of the granulator with a diameter of 4 mm, it is cut into geometrical powder elements. Next, PE enter the reactor with a content of 3.5 wt. including water, 0.6% wt. glue to give a spherical shape and further remove water from PE by adding 2.4% wt. sodium sulfate and distillation of ethyl acetate in a known manner. The characteristics of the obtained powder are shown in the table.

Example 3. In the mixer load 70.0 wt. % pyroxylin 1PL and 28.8 wt. % powder mass. The solvent is added based on the loading of the components: module 1: 3.5 (volume.). The stabilizer of chemical resistance DFA in the amount of 1.2 wt. % is introduced relative to pyroxylin 1Pl with a solvent, and the varnish is mixed for 60 minutes. The resulting powder varnish under pressure of irrigated water is pumped by excess pressure into the granulator where, squeezed through the nozzles of the granulator with a diameter of 4 mm, it is cut into the powder elements specified in geometry. Next, PE enter the reactor with a content of 4.0 wt. hours of water, 0.9% wt. glue to give a spherical shape and further remove water from PE by adding 0.6% wt. sodium sulfate and distillation of ethyl acetate in a known manner. The characteristics of the obtained powder are shown in the table.

Sodium sulfate, acting as a dehydrator of varnish particles, is introduced in an amount of 0.6-3.5% wt. Its increase of more than 3.5% wt. impractical due to the lack of further effect of compaction of dibasic powder granules. The decrease in sodium sulfate is less than 0.6% wt. leads to increased porosity of the granules, i.e. a decrease in their density and, as a consequence, a decrease in bulk density of less than 0.95 g / cm ³ . Run-in of granules to give the desired shape is carried out for 60-90 minutes, depending on the module by water, i.e. creating the necessary ratio D / 2e ₁ . The smaller the module in water and the longer the break-in time (example 1), the more the shape of the element approaches disk-shaped. An increase in water modulus of more than 4.0 will result in sphere-like elements, which reduces the progressiveness of the combustion of gunpowder. An increase in the break-in time of more than 90 minutes is not economically feasible.

From the above table results it is seen that the obtained coarse-grained spherical gunpowder according to the method developed by the authors (examples 1, 2, 3) provides the yield of the target fraction of gunpowder with a given size from 98.0 to 99.0%. The geometric parameters of PE are determined by the diameter of the die and the speed of rotation of the knives of the granulator. While the bulk density of spherical powder is in the range from 0.95 to 0.996 kg / DM ³ .

Outside the boundary conditions (examples 4, 5) it is impossible to obtain spherical powder. A decrease in EA modulus of less than 1.5 (vol.) Leads to heterogeneity of the varnish mixing or, due to a high concentration, leads to a stop of the screw (Example 5), and an increase in EA modulus of more than 2.5 (vol.) Leads to the formation of liquid varnish , the granules do not retain their shape, spread when the suspension moves through the pipeline (example 4).

The method developed by the authors provides coarse-grained spherical gunpowders.

Literature

1. RF patent No. 2382018 of 02.20.2010, IPC C06B 21/00, C06B 25/18. A method of obtaining spherical powder.

2. RF patent No. 2386607 from 04/20/2010. IPC C06B 21/00, C06B 25/18. A method of obtaining spherical powder.

3. RF patent No. 2379271 from 01/20/2010. IPC C06B 21/00, C06B 25/18. A method of obtaining spherical powder.

4. RF patent №2256636 from 07.20.2005. IPC C06B 21/00, 25/24. C06D 5/06. A method of obtaining spherical powder.

5. RF patent No. 2439042 dated 01/10/2012. IPC C06B 21/00. A method of obtaining coarse spherical powder.

Claims (1)

A method of obtaining coarse spherical powders, including the preparation of powder varnish, dispersing it onto spherical particles, followed by removal of solvent from them, characterized in that the powder varnish is initially prepared in the mixer for 60-90 minutes, consisting of 70.0-84.0 wt. . % pyroxylin 1Pl, 15.0-28.8 wt. % powder mass, 1.0-1.2 wt. % stabilizer of chemical resistance and solvent-ethyl acetate with a module of 1.5-2.5 (vol.) to the loading of all components, then the powder varnish is pumped with excess pressure into the granulator, where they are cut into strictly specified dimensions of the powder element, which enter the reactor, where particles give a spherical shape in the presence of 3-4 mass parts of water with a content of 0.6-1.3% wt. protective colloid (glue) and 0.6-3.5% wt. sodium sulfate for 60-90 min and the subsequent removal of volatile solvent from the powder particles.