WO1994011323A1

WO1994011323A1 - Processing of wax-containing explosives

Info

Publication number: WO1994011323A1
Application number: PCT/EP1993/002967
Authority: WO
Inventors: Gregor Fels; Gerhard Ewald
Original assignee: Wasagchemie Sythen Gmbh
Priority date: 1992-11-06
Filing date: 1993-10-26
Publication date: 1994-05-26
Also published as: NO951778D0; AU5371094A; NO951778L; EP0672028A1; DE4237580C1

Abstract

A process and device for processing wax-containing explosives used in particular as fillers of shell warheads allow the wax content of the explosives to be decreased at the same time as the size of the grains of explosive is reduced. The wax-containing explosives are at first dissolved with an appropriate organic solvent, forming a mushy mixture. This mushy mixture is then further dissolved in a stirring container while further organic solvent is added and the temperature is increased. The dissolved phase is then separated from a wax-enriched residue. The separated dissolved phase is submerged into icy water and stirred, causing the precipitation of the explosives in fine crystalline form. Finally the precipitated explosives are separated from the liquid phase. Several post-washing steps may follow in order to further reduce the wax content.

Description

Preparation of explosives containing wax.

The invention relates to a method and a device for the preparation of explosives containing wax, in particular from warhead packing elements containing hexogen or mixtures containing hexogen.

In particular as a result of the political changes of recent times, warhead fillers having an explosive that is phlegmatized with wax have to be disposed of on a large scale. In connection with this application, this primarily means hexogen (RDX) or mixtures containing hexogen. However, the explosive can also be present as octogen (HMX), nitropenta (PETN) or as another crystalline explosive and as a mixture of such explosives.

The present invention is based on the object of proposing a method and a device of the type mentioned at the outset which make it possible to reduce the wax content of the explosive while simultaneously reducing the grain size of the explosive.

To achieve this object, in a generic method it is provided that the wax-containing explosive is dissolved into a pulpy mixture with a suitable organic solvent, that the pulpy mixture is further dissolved in a container with further addition of organic solvent with stirring and supply of temperature, that the dissolved phase is separated from a wax-enriched residue, that the separated, dissolved phase is introduced into ice water with stirring, the explosive being in fine crystalline form falls, and that the precipitated explosive is separated from the liquid phase.

With the method according to the invention there is a substantial reduction in the wax content of the wax-containing one. Explosive substances possible. The crystalline explosive is dissolved in the organic solvent used. The liquid phase is then separated from the wax-containing residue. The precipitated explosive is present with different wax contents depending on the subsequent aftertreatment. The residual wax content which is still present leads to a desensitization of the explosive which facilitates its handling. It is also advantageous that the low wax content reduces the electrostatic chargeability of the explosive particles. The inventive method leads to a recrystallization of the explosive, which is accompanied by a reduction in the grain size of the crystalline explosive. With the method according to the invention, the grain size of the explosive can be reduced to 3 to 8 μm. In this way, the explosive material obtained opens up all those areas of use in which an explosive substance in fine crystalline form is required. For example, the precipitated explosive can be used as a high-energy formulation component in propellant powders or weather explosives.

Acetone is advantageously used as the organic solvent to dissolve the explosive containing wax. In order to ensure safe handling of the unlaborated warhead packing for further treatment, mechanical comminution is advantageously dispensed with. The wax-containing explosive can be dissolved in a closed container for at least 24 hours, preferably for 1 to 2 days, without stirring. The organic solvent is added in an amount such that the packing is covered by the solvent. In the specified period of time, the fillers disintegrate into a mushy mixture which is easy to handle. In a further embodiment of the process, the pulpy mixture is dissolved at a temperature of 55 ° C. to 60 ° C. and a stirring time of 30 to 90 minutes. To separate the dissolved phase from a wax-enriched emulsion-like residue, a service life of preferably 15 to 45 minutes is advantageously provided. The wax-enriched residue sediments from the bottom of the container.

The dissolved phase can then be introduced into an essentially equal amount of ice water with stirring. The precipitated explosive is then advantageously separated from the liquid phase by a filtration process.

To further reduce the wax content of the precipitated explosive, at least one post-washing step with a post-washing agent, preferably ethanol, is provided in a further embodiment. The explosive which has precipitated and is separated from the liquid phase is advantageously treated a second time with detergent, slurried and separated again. It has been shown that the product thus obtained is free from dyes which were originally added to the wax for identification purposes.

If a further reduction in the wax content of the post-washed explosive is desired, post-treatment with petroleum ether or petroleum ether can be provided.

In order to achieve a process which is as economical and environmentally compatible as possible, in a further embodiment of the process according to the invention the liquid phases are prepared, in particular by distillation, and returned to the process.

According to a further development of the method according to the invention, the poorly filterable wax-enriched residue obtained in the process can also be reused and therefore does not have to be disposed of in a complex manner. After cooling, the wax-enriched residue is combined with porous ammonium nitrate prills to form an ANC explosive. After drying in a weak air stream, there is a new ANC explosive in principle which contains the explosive component in a waxy crystalline form.

To carry out the method according to the invention, a device is proposed which has a first release container for dissolving the wax-containing explosive and a downstream second release container which has a stirring device and a heating device. Furthermore, the device according to the invention has a downstream crystallization container which has a stirring device and cooling device and a separating device for separating the precipitated explosive from the liquid phase. The separating device is advantageously designed as a filter chute.

To further reduce the wax content of the precipitated explosive, the separating device is followed by at least one washing device, which is preferably designed as a filter nutsche. In order to recover the liquid phases obtained, the separating device and / or the post-washing device are advantageously assigned means for processing and recycling the liquid phase, which preferably have a distillation device.

The invention will be explained in more detail below with reference to a schematic flow diagram shown in the drawing.

With the device shown schematically in the drawing, packings originating from warheads and containing wax-containing hexogen can be processed. The hexogen contained in the packing is phlegmatized with a wax content of approx. 6%. The average grain size of the hexogen for the individual batches is 35 to 70 μm.

The device for carrying out the method, shown schematically, has a pivotable container 10 in which the packing elements are detached. The tank 10 is followed by a stirred tank 11, which is equipped with an agitator 12 and a riser cooler 13. Furthermore, the Stirring container 11 has a heating device 14, to which a temperature control 15 is assigned. A crystallization vessel 16 connected downstream of the agitation vessel 11 is provided with an agitator 17 and a cooling device 16a. A downstream first filter chute 18 has a filter medium 19 which is designed as a double filter bag in linen quality. The negative pressure of a vacuum source 21 applied to the filter medium 19 can be adjusted by means of a valve 20. A distillation device 22, which has a cooler 23, is assigned to the first filter nutsche 18 in order to process the resulting filtrate.

In principle similar to the first filter chute 18, a downstream second filter chute 24 is formed. As the filter medium 25, the second filter chute 24 has a double filter bag in nylon quality. The applied negative pressure of a vacuum source 27 can be adjusted by means of a valve 26. The filtrate accumulating on the second filter chute 24 is processed via a distillation device 28, to which a cooler 29 is assigned.

A third filter chute 30 has a filter medium 31 which is configured analogously to the filter medium 25. The vacuum of a vacuum source 33 can be set by a valve 32. The filtrate accumulating on the third filter chute 30 is processed by means of an associated distillation device 34, which has a cooler 35.

The filter cake accumulating on the third suction filter 30 can be fed to an extraction device 36 to further reduce the wax content.

Finally, the device shown also has a closed container 37 which is equipped with an agitator 38. Just like the container 10, the container 37 is also designed to be pivotable. Another container 39, which can also be closed, can also be pivoted. The process sequence is to be described in more detail below. The packing elements removed from the warheads are introduced into the closable container 10 without mechanical pretreatment, as symbolized by an arrow 40. Then a lot of acetone is added so that the fillers introduced are just covered. In the container 10, the fillers are dissolved over a period of 1 to 2 days in such a way that they disintegrate into a mushy mixture.

By swirling the container 10, the pulpy mixture is then transferred into the stirred container 11, as shown by an arrow 41. Further acetone is fed into the initially pulpy mixture in the stirred container 11. The amount of acetone supplied is about ten to twelve times greater than the amount of solvent supplied to the container 10. The temperature is set to approximately 55 ° C. with the heating device 14 and the temperature control 15 assigned to it. The solution of the acetone-moist hexogen / wax mixture is carried out with stirring for a period of about 1 hour. The solution process is followed by a subsequent standing time of approximately 15 minutes. Here, a wax-enriched emulsion-like residue sediments at the bottom of the stirred container 11.

The wax-enriched residue can be fed to the container 37 according to arrow 44 via a first outlet 42 and a valve 43. The resulting dissolved phase in the stirred tank 11, in which the hexogen is enriched, is withdrawn via a second outlet 45. The dissolved phase can then flow to the downstream crystallization container 16 via a valve 46 according to arrow 47.

With the agitator 17 being stirred uniformly, the dissolved phase is introduced into ice water which is located in the crystallization container 16. The quantitative ratio between the hexogen-containing acetone solution and the ice water is about 1: 1. The hexogen is precipitated in the ice water and then immediately supplied via an outlet 48, to which a valve 49 is assigned, according to arrow 50 to the downstream first filter funnel 18 . The precipitated hexogen is separated from the liquid phase on the filter medium 19 of the first suction filter 18. Grain size measurements have shown that the precipitated hexogen has an average grain size of approximately 6 μm. Accordingly, the recrystallization that took place in the crystallization container 16 has led to a substantial reduction in the grain size of the hexogen.

The filtrate obtained at the first filter chute 18 reaches the downstream distillation device 22 via an outlet 51, to which a valve 52 is assigned, symbolized by arrow 53. Acetone is obtained as a distillate at the distillation device 22, and this passes through the cooler 23 is returned in the direction of arrow 54 into the stirred tank 11.

The filter cake accumulating on the first filter chute 18 is, as shown by an arrow 55, fed to the second filter chute 24 for subsequent washing. First of all, the still pulpy filter cake is sharply sucked out of the filter medium 25 of the second filter nut 24. It is then washed in portions with ethanol. It is advantageous to slurry completely once and then to rinse again. The product thus obtained, which is present as a filter cake on the filter medium 25, is freed from dyes which were originally added to the wax for identification purposes. Measurements have shown that the average grain size is between 3 μm to 8 μm. The average wax content of the product thus obtained is 3% to 4%.

To recover the ethanol-containing filtrate from the second suction filter 24, it is fed to the distillation device 28 via an outlet 56, to which a valve 57 is assigned, represented by arrow 58. The ethanol obtained as a distillate is returned to the second filter funnel 24 via the cooler 29 in the direction of the arrow 59.

To further reduce the wax content of the filter cake accumulating on the second filter chute 24, this can be done in accordance with Arrow 60 of the third filter chute 30 are supplied. The ethanol-moist filter cake is stirred here in petroleum ether or petroleum spirit. The liquid phase is then filtered off. It is then washed in portions and dried. Measurements have shown that the wax content can be reduced to 0.5 to 1.5% as a result.

To further reduce the wax content, the filter cake accumulating on the third filter chute 30 can be extracted at the extractor device 36. An extraction with petroleum ether according to the Soxhlet principle is carried out. The product present after the extraction has a wax content of less than 0.2%. The grain size is not changed by the extraction. The petroleum ether is circulated and redistilled after saturation.

The residues obtained at the outlets 61, 62 of the distillation devices 28, 34, which in addition to wax also contain a certain amount of hexogen, are fed to the container 37 according to arrow 63. The wax-enriched residue of the stirring container 11 also flows into this container. Depending on the position of a valve 64, the residue of the distillation device 22, which contains wax and hexogen, can also be fed to the container 37. This wax-hexogen fraction is removed from the aqueous distillation residue by filtration on a filter 80. The process water recovered in this way is returned to the crystallization tank 16 in the direction of arrow 81 and cooled there.

The resulting wax-enriched residues, which each contain residual constituents of the hexogen, are drawn up in the container 37 on ammonium nitrate prills, the addition of which is symbolized by an arrow 65. This creates a basically new ANC explosive, which has hexogen as an explosive compared to the previously known explosives of this type.

Then the container content of the container 37 is transferred according to arrow 66 into the closable container 39, which with a fine-meshed bottom sieve 75 for the discharge of the excess Liquid is designed. This excess liquid can be returned to the container 37 according to arrow 76. As shown by an arrow 67, drying takes place in the air stream. The ANC explosive thus obtained consists of approximately 95% ammonium nitrate prills, approximately 4% hexogen and approximately 1% wax. The detonation speed is 2650 m / sec.

Depending on the procedure, the hexogen recovered from the packing with different wax content is obtained. The gradations of the wax contents listed by way of example can be further varied by appropriate process control. The particle size (3 to 8 μm) of the hexogen once achieved is not influenced thereby and allows the explosive thus recovered to be used in propellant powders and / or weather explosives, for example. This particle size, which is in the range between 3 and 8 μm, is achieved according to the process of the invention without turbulent stirring and without the addition of special precipitants. The residual wax content of the hexogen leads to phlegmatization, which facilitates the handling of the explosive.

Claims

Patent claims

1.

Process for the preparation of explosives containing wax, in particular from warhead packing elements containing hexogen or mixtures containing hexogen, characterized in that the explosive containing wax is dissolved into a mushy mixture with a suitable organic solvent, so that the mushy mixture in a container with the further addition of organic Solvent is further dissolved while stirring and increasing the temperature, the dissolved phase is separated from a wax-enriched residue, the separated, dissolved phase is introduced into ice water with stirring, the explosive precipitating in fine crystalline form and the precipitated explosive from the liquid phase is separated.

Second

A method according to claim 1, characterized in that acetone is used as the organic solvent to dissolve the explosive containing wax.

3rd

Process according to Claim 1 or 2, characterized in that the wax-containing explosive is dissolved in a closed container for at least 24 hours, preferably for 1 to 2 days, without stirring.

4th

Method according to one of claims 1 to 3, characterized in that the pulpy mixture is dissolved at a temperature of 55 ° C to 60 ° C and a stirring time of 30 to 90 minutes.

5th

A method according to claim 4, characterized in that a service life of preferably 15 to 45 minutes is provided for separating the dissolved phase from a wax-enriched residue.

6th

Method according to one of claims 1 to 5, characterized in that the dissolved phase in an essentially equal amount

Ice water is entered and the precipitated explosive preferably by a filtration process from the liquid

Phase is separated.

7.

Method according to one of claims 1 to 6, characterized in that the precipitated explosive is subjected to at least one post-washing step with a post-washing agent, preferably ethanol, the precipitated and separated from the liquid phase explosive with the post-washing agent at least once is washed and slurried, and then the detergent is separated.

8th.

A method according to claim 7, characterized in that the washed explosive is treated with petroleum ether or petroleum ether to further reduce the wax content.

9.

A method according to claim 7 or 8, characterized in that the liquid phases, in particular by distillation, are processed and returned to the process.

10th

Method according to one of claims 1 to 9, characterized in that the wax-enriched residue obtained, which has residual components of the explosive, is combined with porous ammonium ^• nitrate prills to form an ANC explosive.

11th

Device for carrying out the method according to one of claims 1 to 10, with: a first release container (10) for dissolving the explosive containing wax, with a downstream second release container (11) which has a stirring device (12) and a heating device device (14), with a downstream crystallization container (16) having a stirring device (17) and a cooling device (16a) and with a separating device (18) for separating the precipitated explosive from the liquid phase.

12th

Apparatus according to claim 11, characterized in that the separating device (18) is designed as a filter groove.

13th

Apparatus according to claim 11 or 12, characterized in that the separating device (18) is followed by at least one post-washing device (24) for further reducing the wax content of the precipitated explosive, which is preferably designed as a filter nut.

14th

Device according to one of Claims 11 to 13, characterized in that the separating device (18) and / or the post-washing device (24) are each assigned means (22, 28) for processing and recycling the liquid phase, which preferably have a distillation device .