WO1999028700A2

WO1999028700A2 - Method for processing explosive waste, method for removing explosives from ammunition and method for production of blank ammunition

Info

Publication number: WO1999028700A2
Application number: PCT/NL1998/000682
Authority: WO
Inventors: Nicolaas Hillegondus Andreas Van Ham
Original assignee: Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
Priority date: 1997-12-02
Filing date: 1998-12-02
Publication date: 1999-06-10
Also published as: WO1999028700A3; NL1007664C2; AU1354599A

Abstract

The application relates to processes for dismantling ammunition. The first aspect of the present application is a method for processing explosive waste to give a stable suspension or emulsion in an inert aqueous medium by adding organic and inorganic thickeners/emulsifiers, as well as subsequent incineration using an incinerator with a cooled injector tube. The second aspect of the present application is a method for removing explosives from ammunition wherein the explosive is flushed out of the ammunition with the aid of an inert liquid such as water under high pressure, preferably of about 1100 bar, using a high pressure spray head and an installation suitable for so removing explosives. The third aspect of the present application is a method for the production of blank ammunition wherein the charge chamber of a grenade body is filled with an inert mass consisting of a light (e.g. PUR-foam) component and a heavy (e.g. gravel) component.

Description

METHOD FOR PROCESSING EXPLOSIVE WASTE, METHOD FOR REMOVING EXPLOSIVES FROM AMMUNITION AND METHOD FOR PRODUCTION OF BLANK AMMUNIΗON

The present invention relates in broad terms to the dismantling of ammunition. The invention encompasses three aspects, which in combination with one another offer a complete process for the disassembly of ammunition and the processing of the waste produced thereby. The first aspect (Claims 26-50) of the invention relates in broad terms to the "removal of explosive from ammunition"; the second aspect (Claims 1-25) of the invention relates in broad terms to "the processing of explosive waste"; and the third aspect (Claims 51-72) of the invention relates in broad terms to "the production of blank grenades/ammunition". As will be seen, the said three aspects of the invention can not only be used in combination but can also be used entirely independently of one another. The invention will now be discussed aspect by aspect below.

According to the first aspect, the present invention relates to a method for removing explosive from ammunition or ammunition components.

The dismantling or disassembly of ammunition or ammunition components is known per se. As far as the explosive charge is concerned, this is usually effected by melting out the solid explosive, which melts at relatively high temperatures. In this context, the melting point of the explosive is dependent on the type of explosive and in general is above 60 °C. Said melting has a number of disadvantages. Firstly, explosive residues readily remain behind in the ammunition. Secondly, the majority of explosives are toxic and sometimes even carcinogenic, so that, especially in the case of melting out, precautionary measures and safety measures have to be taken into account in connection with the formation of vapour. During the melting operation the liberated vapours must not be discharged into the atmosphere and must be thoroughly cleaned. Furthermore, the heat required for melting out demands a great deal of energy. A very significant disadvantage of melting out is that this can only be used in the case of explosives capable of being melted out and, consequently, cannot be used in the case of plastic bonded explosives (so-called PBXs).

The aim of the present invention is to provide an improved method for removing explosive from ammunition or ammunition components.

Said aim is achieved according to the first aspect of the invention in that the explosive is flushed out of the ammunition with the aid of an essentially inert liquid, such as water, under high pressure. In this context under high pressure is understood to be a liquid pressure of more than 400 to 500 bar, such as, for example, a liquid pressure of more than 700 bar.

It is found to be possible to squirt or flush the explosive completely out of the ammunition by spraying with a liquid under high or very high pressure. The liner, with which the chamber in which the explosive is stored is lined in order to improve the adhesion of the explosive to the walls delimiting the chamber, can also be flushed out by spraying with an essentially inert liquid, or at least a liquid which is inert with respect to the explosive, sprayed under such a high pressure. Appreciably less carcinogenic explosive in vapour or dust form is liberated with a method of this type than with the conventional melting process.

Experiments have shown that very good results can be achieved when the liquid pressure is in the range of 800 to 1500 bar, such as, for example, in the region of approximately 1100 bar. On the grounds of safety considerations, the liquid will in general be sprayed at a pressure which is less than 20% of the initiation pressure of the explosive to be removed, the liquid pressure preferably not being higher than 1500 to 2000 bar on the grounds of structural considerations.

Very good results can be achieved according to the invention if a spray head provided with one or more nozzles is used for spraying the liquid, which spray head is moved continuously or stepwise, during spraying, in the direction of the explosive at a speed such that as spraying progresses it is always ensured that that portion of the explosive located in front of and/or around the spray head is flushed away. In this way the distance between the spray head and the explosive still to be removed, the momentary explosive front, is always adjusted during or according to the progress of the removal process (flushing out process). In this way it is possible to prevent the efficiency or effect of the liquid sprayed under high pressure from decreasing substantially as the distance between the spray head and the residual explosive to be removed increases. Furthermore, it is possible to ensure in such a way that all locations in the charge chamber and thus all portions of the explosive originally present in the ammunition are reached. In order to prevent the spray head from being able to come into contact with explosive, in particular the explosive front, an overpressure sensor can be provided which emits a stop signal, causing spraying to stop, for example by switching off the high pressure pump, if the pressure exceeds the set liquid pressure by a certain amount, such as 10%. The method according to the invention can be used highly advantageously for ammunition or ammunition components in which the explosive is accommodated in a chamber formed in a body. In this context consideration can be given, for example, to a grenade body in which a chamber has been formed for the so-called explosive charge consisting of explosive. Such a body usually has an opening from said chamber to the outside, for example the opening through which the detonator or so-called fuse is introduced into the explosive charge. In such a case the body will advantageously be set up with the opening facing downwards during spraying, the liquid will be sprayed via a spray head provided with one or more nozzles and, for spraying, the spray head will be inserted into and/or through the opening from underneath in an upwards direction in order to be able to flush the explosive out of the chamber when spraying. With this arrangement, the opening present in such an ammunition body, such as a grenade body, thus on the one hand forms an access for the spray head and, on the other hand, forms a discharge opening for the sprayed liquid and explosive detached by spraying, since the opening is located at the bottom, so that the mixture of sprayed liquid and explosive detached by spraying is spontaneously able to flow out of the charge chamber in the body under the influence of gravity.

In order to be able to remove the explosive effectively and completely from a body of ammunition or an ammunition component enclosing a chamber filled with explosive using this procedure it is advantageous according to the invention if the spray head, during spraying, is moved upwards in said chamber, stepwise or continuously, at a speed such that explosive has been completely, or at least virtually completely, removed from the portion of the chamber which is located under the spray head. In this context it is pointed out that moving upwards is not per se understood as moving vertically straight upwards but can equally well be understood as moving upwards at an angle. What is important is, rather, that the opening through which the injection nozzle is inserted inside is located at the bottom in connection with sprayed liquid and explosive detached by spraying flowing away and that the spray head, or at least the liquid sprayed therewith, is able effectively to reach the entire charge chamber. In this context it has been found that the forward or so-called upward speed of the spray head is advantageously in the range of 200 to 1000 mm per minute, which is dependent on the type of ammunition to be cleaned and the quantity of liquid sprayed per minute. In order to prevent the spray head from being able to come too close to the explosive, an overpressure sensor, which has been discussed above, which is able to produce a stop signal to terminate the spraying process will advantageously be provided.

The result of the method according to the invention can be appreciably improved if the spray head is rotated during spraying. By this means it is ensured that all portions of the explosive present in the ammunition are reached by the sprayed liquid in order to be able to detach them by spraying. In this context it has been found that relatively low rotational speeds for the spray head in a range of approximately 0.3 to 10 revolutions/ second, more particularly in the range from 0.5 to 5 revolutions/second, for example 1 revolution/second, suffice. Such relatively low speeds of revolution have the advantage that the wear load, to which the spray head, in particular the rotary bearing thereof, is subjected as a consequence of the high to very high liquid pressure is kept within bounds.

Furthermore, a very good spraying result can be achieved according to the invention if the spray head is provided with at least one nozzle directed essentially forwards and at least one nozzle directed sideways or obliquely sideways. In this way it can be ensured, on the one hand, that the explosive in the region located in front of the spray head in the direction of movement is removed by the liquid jet from the nozzle directed essentially forwards and, on the other hand, that the explosive located around said region is removed in a second stage by the jet from the at least one nozzle directed sideways or obliquely sideways. As a consequence of flushing out/spraying clean ammunition by means of a spraying process of this type, sprayed water containing entrained individual explosive particles is produced. Such a mixture of liquid and explosive particles can be further treated in a relatively simple manner. In this context consideration can be given, for example, to collection of the liquid used for spraying, with the particles of explosive contained therein, feeding the collected mixture to a separator, such as a centrifuge, in order to separate the particles of explosive from the liquid, after which the liquid is once again suitable for flushing explosive out of ammunition by spraying. With such a process the liquid can thus be circulated in a cycle and does not have to be discharged. The explosive separated off can then be stored, re-used, for example as industrial explosive, destroyed or subjected to a waste treatment process.

In order to have an adequate stock of spray liquid available for the flushing out process and not to incur any delay as a consequence of the treatment in the separator, it is advantageous in this context according to the invention if the liquid issuing from the separator is fed to a reservoir for interim storage, it then being possible to feed the liquid from the reservoir back to the spraying process. Before the used spray water/the liquid is recycled to the reservoir, it is passed through a percolator (no. 39 in Figure 6). All suspended particles smaller than 10 micron are filtered off in this percolator. In order also to remove from the liquid very fine explosive dissolved, dispersed or emulsified in the liquid, it is preferable if the liquid is passed through a charcoal filter, in particular an active charcoal filter, downstream of the separator and before it is sprayed again. This prevents the liquid from becoming saturated with explosive. Specifically, when the saturation point is reached foaming occurs, which renders the liquid less suitable to unsuitable for spraying in order to remove further explosive from further ammunition. Advantageously, with this arrangement the liquid is fed from the reservoir through a charcoal filter and then fed back into the reservoir again, in particular via a separate circulation process. The reason for this is that this offers the additional possibility of further filtering the liquid when the spraying process as such is not in operation. According to the first aspect thereof, the invention also relates to equipment for application of the method for removing explosive from ammunition or ammunition components.

According to the first aspect thereof, the invention also relates in particular to a spray head, in particular for carrying out the method for removing explosive from ammunition or ammunition components, comprising a spray head body, provided with a multiplicity of nozzles, suitable for fitting on a spray lance, the spray head having a longitudinal axis extending in the extension of the spray lance, characterised in that the spray head has one or more nozzles, preferably arranged symmetrically with respect to the longitudinal axis as far as the reaction forces in respect of spraying experienced in the transverse direction are concerned, and directed essentially forwards with respect to the longitudinal axis, and one or more nozzles directed sideways with respect to the longitudinal axis, which latter nozzles are likewise preferably arranged symmetrically with respect to the longitudinal axis as far as the reaction forces as a consequence of spraying experienced in the transverse direction are concerned. The advantages of such a spray head have already been discussed above. Advantageously, with this arrangement the angle of the spray direction(s) of the nozzles directed essentially forwards is in the range of approximately 0° to approximately 30° with respect to the longitudinal axis. The angle of the spray direction(s) of the nozzles directed sideways will, with this arrangement, be in the range of approximately 40° to approximately 110°, preferably in the range from approximately 40° to approximately 90°, such as, for example, approximately 60 and/or approximately 45°, with respect to the longitudinal axis, measured from the front of the spray head facing away from the spray lance. With this arrangement the nozzles directed essentially forwards can comprise one nozzle but will preferably comprise two or more nozzles arranged symmetrically with respect to the mid longitudinal axis. When one nozzle is used this will preferably be directed straight ahead, in connection with the symmetry, that is to say the angle of the spray direction will be approximately 0° with respect to the longitudinal axis. In this context the symmetry is of advantage in order to ensure that forces acting laterally on the spray head as a consequence of spraying liquid under very high pressure will cancel one another out as far as possible. In the case of the nozzles directed sideways, the symmetry plays a lesser role as far as the spray direction is concerned, for example it is conceivable to use two nozzles directed sideways which are located in a single mid longitudinal plane, one at 45° with respect to the mid longitudinal axis and the other at 60° with respect to the mid longitudinal axis.

In order to counteract a reduction in the spraying effect as a consequence of wear phenomena, it is advantageous according to the invention if the walls of the channels to the nozzles, at least at the nozzle ends thereof, are coated with or are constructed with an erosion- or wear-resistant material, which preferably has a Mohs hardness of at least 9, such as a natural or synthetic precious stone, for example ruby.

According to the first aspect thereof, the invention also relates to an installation for removing explosive from ammunition, comprising: one or more spray lances having a spray head according to the invention, pressure means for pressurising a liquid, such as water, to at least 700 bar, preferably at least 800 to 900 bar, and feeding said liquid to the spray lances, frame sections for holding the ammunition in place, moving means for inserting each of the spray lances in the longitudinal direction of the spray lances into an ammunition component, collection means for collecting sprayed liquid and explosive particles, detached by spraying, originating from the ammunition which has been flushed out or is to be flushed out by spraying. Advantageously, according to a preferred embodiment, said installation is also provided with separating means for separating off from the liquid explosive particles entrained therein. In addition or preferably even as an integral feature, filtering means, preferably an (active) charcoal filter, will be provided for separating off from the liquid explosive emulsified, dispersed or dissolved therein. When separating means are also used, the filtering means will then preferably have been placed downstream of the separating means, so that the separating means have already removed the relatively coarse explosive portions/particles from the liquid before the latter is fed through the filter. According to an advantageous further embodiment of the installation according to the invention, a reservoir is positioned between the separating means and the pressure means, the filtering means then preferably being incorporated in a separate circuit starting and ending at the reservoir, wherein pumping means are also provided which can be activated independently of whether or not spraying is being carried out, so that the liquid can also be treated in the filtering means after the spraying process or before the spraying process or independently of the spraying process. The reservoir also serves for cooling the process water, which is readily heated to 50° during the spraying process. According to the second aspect, the invention relates to a method for processing explosive waste, an incinerator suitable for this purpose and an injector tube suitable for feeding the explosive waste into the incinerator or the method for processing explosive waste.

With the known methods for processing explosive waste, in particular originating from dismantled or disassembled ammunition, the explosive is stored in solid form, that is to say after melting out as described above it is solidified again and stored as explosive. The explosive can then be further used as, for example, industrial explosive, etc. Said storage of explosive is associated with the obvious risks. In view of the current relatively high degree of demilitarisation, or at least the great need therefor, such storage of explosive, which actually is a waste product originating from the dismantling/disassembly of ammunition, gives rise to increasing problems or will give rise to such problems, especially because the supply of explosive exceeds the demand for explosive for, for example, industrial applications. The aim of the present invention is to provide a solution to this. In this context the aim of the present invention is, in particular, to provide a method for processing explosive waste into a product which can be stored and transported relatively safely and easily and which can readily be further processed.

US-A 5 506 366 discloses a method for desensitising explosives in an aqueous medium. With this method portions of solid explosive are brought into particulate form and combined with water to give an aqueous slurry. A water-absorbent, cellulose-like material, such as paper or cotton, is added to said slurry, which material must absorb a substantial proportion of the water or all the water in order to obtain a highly viscous mass of a consistency such that it can be shaped and extruded and, with certain embodiments of the method, can be pumped. The disadvantage of this is that it is not possible in this way to obtain a relatively fluid and readily pumpable suspension with which the explosive is desensitised in the long term.

US-A 4 231 822 discloses another method for the desensitising of explosives. With this method the explosive is brought into contact with a reducing agent and kept in contact with the latter for some time. To this end the reducing agent can have been dissolved in water and the explosive placed in the water containing the reducing agent dissolved therein. When the explosive placed in water containing reducing agent has been adequately treated with the reducing agent, the explosive treated with the reducing agent is separated off from the solution again. There is no question here of an aqueous suspension/emulsion containing a thickener and/or emulsifier.

According to the second aspect of the invention, said aim is achieved in that the explosive waste is processed to give a stable suspension or emulsion in an inert aqueous medium, in particular water, by adding one or more thickeners and/or emulsifiers. In this way the mixture of liquid and explosive particles removed from ammunition which remains after flushing out by spraying in accordance with the first aspect of the present invention can be processed by the addition or one or more thickeners and/or emulsifiers to give a stable suspension or emulsion, which can easily be kept for a few to several days without demixing or precipitation of the explosive from the suspension or emulsion taking place. It is also conceivable for explosive currently in store to be mixed with water and then processed by adding one or more thickeners and/or emulsifiers to give a stable suspension or emulsion. As will be apparent, such a stable suspension or emulsion, with which precipitation or demixing is delayed or counteracted at least for some time, can be transported relatively easily and offers possibilities for further processing of the explosive waste. Either an organic or an inorganic thickener and/or emulsifier or a mixture of the organic and inorganic thickener and/or emulsifier can be used as thickener and/or emulsifier according to the invention. A stability period of 1 to 2 weeks is achievable with an organic thickener or emulsifier on its own and when a combination of an organic thickener or emulsifier followed by an inorganic thickener or emulsifier is used it has been found that a suspension or emulsion which is stable for one to three months or even longer can be obtained.

As far as an organic thickener or emulsifier is concerned, it has been found that good results are obtained when such an organic thickener or emulsifier is added to give a proportion by weight of less than approximately 10%, preferably less than approximately 6% and more preferentially to a proportion by weight of approximately 1% to 4%. In this context, according to the invention a thickener or emulsifier based on cellulose or starch, such as carboxymethylcellulose added to a proportion by weight of, for example, 1% to 5%>, has proved highly advantageous as organic thickener or emulsifier. Thickeners or emulsifiers of this type are relatively easily obtainable and relatively easy to process and present few or no problems, for example, on further processing by incineration.

As far as the inorganic thickener or emulsifier is concerned, it has been found that very good results are obtained when this is added to give a proportion by weight of less than approximately 10%, preferably less than approximately 6% and more preferentially to approximately a proportion by weight of 1% to 4%. A thickener or emulsifier based on silicon, in particular a polymer based on silicon, such as, in particular, water-glass or silicon dioxide, has proved highly advantageous as inorganic thickener or emulsifier. However, equivalents of these, such as aluminium oxide, titanium oxide and zirconium oxide, can also be used as inorganic thickener and/or emulsifier according to the invention.

In order to obtain a suspension or emulsion with long term stability, it is advantageous according to the invention if the inorganic thickener has a particle size of less than 10 μm, preferably less than 0.1 μm. In this context, the inorganic thickener is preferably in powder form in the initial state. In particular, it has proved advantageous with regard to the stability of the suspension or emulsion and the transportability, in particular the pumpability, thereof if the average particle size of the inorganic thickener and/or emulsifier is in the range from 10 nm to 1000 nrn, preferably 10 nm to 100 nm, such as approximately 40 nm.

Furthermore, according to the invention an emulsion or suspension which, on the one hand, has long term stability and, on the other hand, has a viscosity such that the emulsion can still be transported, and in particular pumped, easily is obtained if the inorganic thickener has a specific surface area, the so-called BET surface area, in the range from 0.1 to 200 m²/g, preferably in the range from 1 to 80 m²/g, and more preferentially in the range from 10 to 70 m²/g, such as approximately 50 ± 15 m²/g. In particular, said specific surface area is/has been determined in accordance with DIN 66131.

If the thickened final mixture contains no more than approximately 70% by wt, preferably no more than approximately 50% by wt, explosive, the final mixture can be transported and stored without any problems worthy of mention, the risk of explosion in particular being relatively low to zero.

In order to be able to transport the explosive waste after processing to give a stable suspension or emulsion through pipes, by pumping, etc., it is important that the particle size of the explosive is less than approximately 6 mm, preferably less than or at most equal to approximately 5 mm, in particular less than or equal to 3 mm. In practice, it is found that explosive particles obtained using the method according to the first aspect of the invention, on their own or still mixed with the (spray) liquid in general have a particle size of less than approximately 5 mm, and usually even a particle size of less than or equal to 3 mm.

According to the second aspect of the invention, the latter further relates to a method for processing explosive waste wherein a suspension or emulsion containing explosive waste, which suspension or emulsion has preferably been obtained in accordance with the method according to the main part of the second aspect according to the invention, is incinerated in an incinerator at a temperature of between 300 °C and 1500 °C, with an excess of oxygen. In this way the explosive waste which has been processed to give a stable suspension or emulsion in an inert aqueous medium can be completely disposed of in a relatively simple manner by an incineration process. In this context the disposal of explosive waste by means of an incinerator is, in particular, rendered possible because the explosive processed to give a stable suspension or emulsion in an aqueous medium can, in particular as a consequence of the stability thereof, be fed to an incinerator in a well- controlled and metered manner, so that hazardous, explosive situations can be avoided and, as a consequence of the metered feed, disasters, should these occur, can remain controllable.

In this context with regard to the control of an incineration process according to the invention it has proved to be particularly advantageous if the incineration is carried out as a two-step incineration, the first step being carried out at a temperature of approximately 400 to 800 °C, preferably approximately 400 to 600 °C, with a slight excess of oxygen, and the second step being carried out at a temperature of approximately 800 to 1200 °C, preferably at approximately 1000 °C. What is achieved by this procedure is that the explosive is completely decomposed in the first step at the relatively lower temperature into non-hazardous, in particular non-explosive, constituents, which decomposition takes place virtually instantaneously, and that the decomposition products produced during the decomposition are completely incinerated in a second incineration step with a substantial excess of oxygen to give incineration products which can be subjected in a manner which is customary per se to after-treatments known per se for the incineration of waste.

Highly controlled incineration can be achieved according to the invention if the incinerator comprises a so-called fluidised bed furnace, in which at least the first step of the incineration takes place. With this procedure the bed will be pre-heated to the desired temperature for the first incineration step, after which said temperature is or can be completely or partially maintained by the decomposition of the explosive, that is to say, after heating of the bed, the explosive waste is used as fuel for keeping the bed hot. With this procedure the bed is advantageously a sand bed, such as a bed containing river sand. Such a sand bed ensures good contact between the emulsion or suspension containing explosive waste and the air present in the bed. With this procedure the emulsion or suspension will preferably be introduced into the so-called heart of the fluidised bed in the furnace.

In order to be able to control the incineration process well, to prevent explosions as far as possible and, should explosions occur, to limit the consequences of these as far as possible, the emulsion or suspension according to the invention is preferably brought into droplet form and fed in droplet form to the incineration process, in particular the first step thereof. Bringing into droplet form can be effected in a relatively simple manner by blowing the emulsion or suspension with compressed air into the furnace in accordance with the so-called ejector principle.

In order to increase the safety of the incineration process, it is advantageous according to the invention if the emulsion or suspension is fed to the incinerator by means of a so- called peristaltic pump. With such a peristaltic pump direct contact between moving parts and the emulsion or suspension is prevented and in the event of too high a pressure the hose can, if necessary, burst or detach.

In order to counteract heat originating from the incinerator acting on the emulsion or suspension, and consequently to counteract any possible risk of explosion, it is advantageous according to the invention if the emulsion or suspension is injected into the incinerator via an injector tube, preferably of the compressed air type, and if the injector tube is cooled. What is achieved by injecting via an injector tube is, on the one hand, that the quantity injected at any point in time is always relatively small and, on the other hand, that said quantity and the injection medium can be cooled relatively well. For cooling, use can be made of, for example, water which is fed through the jacket of the injector tube. In order to be able to shut off the stock of emulsion or suspension from the incinerator in the event of too high a pressure build-up, for example caused by an explosion, in the incinerator, it is advantageous according to the invention if the injector tube or the emulsion/suspension feed thereof is provided with a non-return valve which closes in the event of flash-back from the incinerator.

In order further to increase the safety of the incineration process, it is advantageous according to the invention if a shut-off valve, which optionally can be integrated with the non-return valve, is fitted in the emulsion or suspension feed to the incinerator and is closed in the event of a disaster, such as an explosion, a pressure in excess of a limit, an excessively high temperature, etc. in the incinerator itself or in a component connected thereto. According to the second aspect, the invention further also relates to an incinerator, in particular a fluidised bed furnace, suitable for carrying out the method according to the sub-aspect of the second aspect of the invention.

According to the second aspect, the invention further also relates to an injector tube suitable for carrying out the incineration method according to the second aspect of the invention.

According to the second aspect, the invention further also relates to a stabilised mixture obtained according to the second aspect of the invention and to a mixture which in terms of composition complies with the quantities and/or constituents as specified in said method and has not per se been obtained directly by said method. According to the third aspect, the invention relates to a method for the production of blank ammunition, a grenade body obtained in this way and blank ammunition obtained in this way.

When manufacturing blank ammunition, a charge chamber in a body, such as a grenade body, is often filled with an inert mass. This is done in order to provide the blank ammunition for training purposes with adequate weight. In this context the inert mass used is in general a material which is inexpensive and which preferably can end up in the environment without causing any major problems. Such a material is, for example, sand. The disadvantage with this procedure is that metering of the inert mass is not very accurate and that the inert mass does not completely fill the charge chamber and sometimes is loose therein. The consequence of this is that the ballistics characteristics of blank ammunition are frequently poor or at least leave something to be desired.

The aim of the invention according to the third aspect thereof is to provide an improved method for the production of blank ammunition, wherein a charge chamber in a body, such as a grenade body, is filled with an inert mass.

Said aim is achieved according to the invention in that the inert mass consists of a component system of at least two components, the one component of which is a relatively heavier component having a higher relative density and the other component is a relatively lighter component having a lower relative density. In this way it can be ensured that the charge chamber is completely filled with the component system and the inert charge provided by the component system is thus fixable, if this at least is not too readily capable of flow, such as in the case of a liquid or sand. With this procedure the ratio of the components is preferably so chosen that the relative density of the component system is matched to the desired ballistics characteristics of the blank ammunition and preferably the weight distribution of the component system is made uniform, that is to say the component system as it were forms a homogeneous mixture as far as the relative density is concerned. The ballistics characteristics of blank ammunition can thus be improved appreciably.

The method according to the invention can advantageously in particular be used on conventional grenade bodies. In this context a conventional grenade body is understood to be a body which has the same appearance as the body of so-called live ammunition, or a body which was originally intended for processing into live ammunition or has formed part of live ammunition but from which its explosive charge consisting of explosive has been removed, for example in accordance with the method according to the first aspect of the invention. With this method, the charge chamber intended for explosive is filled with the inert component system instead of with explosive, the relative density of the lighter component then being lower than the relative density of the explosive, the relative density of the heavier component being higher than the relative density of the explosive and the ratio of the components of the component system then being so chosen that the relative density of the component system as a whole is equal to or at least essentially equal to that of the explosive which was originally intended for the conventional grenade body. In this context it must be pointed out that explosives of numerous types are known and used and that these various explosives each have a specific relative density. The ballistics characteristics of blank ammunition obtained in this way are appreciably better than those of the corresponding live ammunition. The reason for this is that in the case of live ammunition the weight of explosive contained in the live ammunition shows a relatively wide spread, as a consequence of, inter alia, air inclusions, and consequently also has a relatively inhomogeneous weight distribution. However, a certain ideal mass and ideal mass distribution are assumed when designing live ammunition. The mass distribution of the blank ammunition obtained in this way can, however, also be appreciably improved, especially if suitable components are chosen for the inert component system.

Very good results can be achieved according to the invention if the material used as the lighter component is foamable material which is injected, can be injected or is otherwise introduced in liquid form into the charge chamber and is allowed to foam and cure in the charge chamber and if the material used as the heavier component is a granular material. With this procedure the granular material can have been mixed with the foamable material in a desired ratio before the foamable material is introduced in order to be introduced simultaneously with the foamable material into the charge chamber.

In this context it is particularly advantageous according to the invention if the granular material and the foamable material in combination are selected such that the granular material can be entrained by the foamable material during foaming and is fixed in the foamable material during curing. In this context it will be clear that, depending, on the one hand, on the properties of the granular material, such as particle size and relative density, and, on the other hand, on the settlement-preventing or floatation-promoting properties of the foamable material, it is possible to obtain blank ammunition filled with an inert mass having a highly homogeneous relative density distribution. Highly advantageously, a so-called PUR foam has proved very suitable for use as the foamable material. PUR foam is very light, relatively inexpensive and does not cause much pollution in the environment.

According to an advantageous further embodiment of the invention, a gravel is used as the heavier component.

According to an advantageous embodiment, a granular material or a gravel having a particle size of less than 8 mm is used. A material having such a particle size can be entrained relatively well by the foamable material during foaming without settling out too much therein and thus rendering the final relative density distribution of the cured component system inhomogeneous. In order to be assured of a good homogeneity with regard to the weight distribution of the granular material or gravel it is advantageous according to the invention if a granular material or a gravel having a spread in particle size of less than 3 mm is taken.

Very good results can be achieved according to the invention if a granular material or a gravel having a particle size which is in the range between 2 mm and 4 mm is taken.

Blank ammunition which in terms of properties comes very close to the live ammunition, at least as defined at the design stage, and is even an improvement on live ammunition produced in practice can be obtained according to the invention if the empty grenade body is weighed and the quantities of the components of the component system which are to be used are then so determined that the total weight of the empty grenade body and of the quantities of the components to be used is essentially equal to a predetermined value. In this context said predetermined value will depend on the design weight of the live ammunition.

When granular material or gravel is used as the heavier component of the component system it is particularly advantageous according to the invention if the grenade body is weighed and the charge chamber thereof is then filled with a quantity of granular material which is chosen such that the total weight of the grenade body and the granular material has a predetermined value (which predetermined value will be dependent on/will be determined by the design weight of the live ammunition) and if, after said filling with granular material, an injection nozzle is inserted in the charge chamber of the grenade body, which is preferably set up vertically, in order to inject the foamable material into the charge chamber via said injection nozzle. As the foamable material expands, the foamable material will then raise the granular material with it and distribute this over the charge chamber. In order to improve the homogeneity of the distribution of the granular material or the gravel in the charge chamber and in particular in order to be able to make this virtually homogeneous, it is advantageous according to the invention if the injection of foamable material takes place while the injection nozzle is moved stepwise or continuously from the bottom of the charge chamber upwards in the charge chamber and is withdrawn therefrom over a period such that the material which is still foaming has not yet completely filled the charge chamber. This makes it possible for the passage via which the injection takes place to be closed off in good time and, if appropriate, for a dummy detonator or dummy fuse to be inserted therein. A period of 5 to 10 seconds is found to be sufficiently fast for this.

In order to minimise the spread in the final total weight of the blank ammunition it is advantageous with this procedure according to the invention if the quantity of foamable material is a predetermined fixed quantity or fixed weight. In this way the final weight of the blank ammunition can be determined within very close tolerances of a few grams, which is an appreciable improvement compared with the spread in the total weight of so- called live ammunition which occurs in practice. In order virtually completely to eliminate the spread in final total weight with respect to a nominal design weight for live ammunition, the procedure will preferably be as follows: the grenade body is weighed; said body is filled with a variable weight of granular material and a fixed weight of foamable material, the variable weight of granular material or gravel being so chosen that the total of grenade body weight + weight of fill with granular material/gravel + weight of fill with foamable material is equal to the nominal design weight. The spread in final weight will then be very slight and ascribable exclusively to gases, liquid and foam which have escaped from the grenade body during foaming.

In order to ensure that the relatively heavier component, in particular the granular material or gravel, is not able partially to escape from the charge chamber of the body or grenade body during foaming, it is advantageous if the charge chamber of the grenade body is closed off at the top by a cap, in particular a screw cap, which is provided with a passageway which is so sized that the granular material is held back and air and foamable or foaming material can be allowed to pass through. Said cap can optionally have been so constructed that it leaves a cavity behind in the cured, completely foamed component system, which cavity corresponds to the cavity formed in live ammunition in the explosive charge to accommodate the detonator or so-called fuse. According to the third aspect, the invention also relates in particular to a method for the production of blank ammunition, wherein the explosive in the grenade body of a conventional grenade body filled with explosive is removed from the explosive chamber, preferably in accordance with the method according to the first aspect of the invention, and wherein the grenade body from which the explosive has been removed is then used for the production of blank ammunition in accordance with the third aspect of the invention.

The third aspect of the invention also relates to a grenade body obtained using the method according to said third aspect of the invention. In particular, the invention therefore relates to a grenade body for blank ammunition having a charge chamber filled with inert mass, characterised in that the inert mass consists of a component system of at least two components, the one component of which is a relatively heavier component having a higher relative density and the other component of which is a relatively lighter component having a lower relative density. In this context the grenade body can be a grenade body of a conventional grenade, the charge chamber being the explosive chamber thereof intended for explosive, and wherein the relative density of the lighter component is lower than that of the explosive and the relative density of the heavier component is higher than the relative density of the explosive. Advantageously, the lighter component comprises a foamable material which has been introduced into the charge chamber in liquid form and has been foamed and cured therein and the heavier component comprises a granular material. The foamable material can be a PUR foam and the heavier component can be gravel.

According to the third aspect, the present invention also relates to blank ammunition comprising a grenade body according to the third aspect of the invention.

The invention will be explained in more detail below with reference to illustrative embodiments shown in the drawing. In the drawing, Figures 1-6 are essentially intended to illustrate the first aspect of the invention, Figures 7 and 8 are essentially intended to illustrate the second aspect of the invention and Figures 9, 10 and 11 are essentially intended to illustrate the third aspect of the invention. More particularly, the drawing shows: in Figure 1 a view of a longitudinal section of a grenade body, in particular of a so- called 155 mm grenade, filled with explosive; in Figure 2 a view of a longitudinal section corresponding to that in Figure 1 during flushing out of the explosive/explosive charge by spraying; in Figure 3 a top view of an advantageous embodiment of a nozzle which can be used when flushing out a grenade body by spraying; in Figure 4 the view of the longitudinal section, partially in normal view, according to the arrows IV-IV in Figure 3; in Figure 5 the view of the longitudinal section according to the arrows V-V in Figure 3; in Figure 6 a diagrammatic sketch of an installation which can be used for flushing the explosive charge out of grenade bodies by spraying ; in Figure 7 a diagrammatic set-up of an incinerator which can be used for incinerating explosive waste; in Figure 8 a diagrammatic set-up of a metering system for feeding explosive waste into an incinerator such as the incinerator in Figure 7; in Figure 9 a diagrammatic view of a longitudinal section of a conventional grenade body during the initial stage of introducing an inert mass therein; in Figure 10 a view corresponding to that in Figure 9 during a second stage; in Figure 11 a view corresponding to that in Figures 9 and 10 during the final stage.

Figure 1 shows, diagrammatically, a view of a longitudinal section of a grenade body 1 of a so-called 155 mm grenade, the front of which is pointing downwards. The grenade body 1 encloses a charge chamber 5 in which an explosive charge comprising explosive 4 is accommodated. During the production of the grenade body 1, said explosive 4 has, for example, been poured in liquid form into the charge chamber 5 and then hardened. The grenade body 1 is provided at the front with a threaded bore 2 into which a detonator or so-called fuse (not shown) can be screwed such that said detonator or so-called fuse protrudes into the cavity 3 which has been formed in the front part of the charge of explosive 4.

The explosive can be of diverse types, such as, for example, TNT (trinitrotoluene) or hexal (hexogene + aluminium), but also of other types which have not been mentioned, in Figure 1 and for all aspects of the invention.

According to the first aspect of the invention, the explosive charge consisting of explosive 4 can be removed from the charge chamber 5 by inserting a spray head 6 via the threaded passage 2 into the cavity 3 for the detonator or so-called fuse. For this purpose the spray head 6 will have been fixed on a lance 7, via which the liquid to be sprayed can be fed to the spray head 6. A liquid which is inert with respect to the explosive 4 is sprayed via the spray head 6 under a very high pressure of, for example, approximately 1100 bar into the charge chamber 5. As a consequence of the high pressure of the liquid, which highly advantageously can be water, the liquid breaks up the solid explosive 4 into particles of explosive of variable size, which in the case of TNT are generally smaller than about 5 mm. By, as is shown in Figure 2, positioning the grenade body 1 with the opening running from the charge chamber 5 to the outside facing downwards, for example at an angle (Figure 2) or optionally truly vertical (Figure 1), it is ensured that the liquid injected via the spray head 6 is spontaneously able to flow away out of the grenade body 1 and specifically is able to do so at that side of the explosive 4 from which explosive 4 has already been removed. The explosive particles detached by the liquid by spraying are entrained with the sprayed liquid flowing, in turn, out of the grenade body 1.

As will be clear per se from Figure 2, the explosive can be flushed out from the grenade body 1 by spraying if the spray head 6, after it has been introduced into the cavity 3 for the detonator or so-called fuse is kept essentially in one fixed position while spraying liquid. The disadvantage of this is, however, that the explosive located at the base 8 (top end) of the grenade body 1 is less effectively detached by spraying and removed. In order to overcome/avoid this problem it is advantageous according to the invention if the spray head 6 is continuously moved forward in the direction of arrow S, that is to say in the longitudinal direction of the grenade body 1, while spraying. A front 9 of flushed-out explosive progressing in the direction of base 8 can thus be created, in which context the distance between the front 9 and the spray head 6 will be more or less constant if the speed of propulsion in the direction S has been suitably chosen. In the case of a 155 mm grenade body filled with TNT a speed of propulsion in the direction S of approximately 500 mm per minute has been found to be achievable and to lead to good results. In order to achieve uniform crumbling away/advance of the spray front 9 it is furthermore advantageous according to the invention if the spray head 6 is rotated in the circumferential direction about the longitudinal axis of the lance 7 while spraying the essentially inert liquid, such as water.

In order to achieve a good result when removing explosive from ammunition it has proved advantageous according to the invention to make use of a spray head 6 which is provided with at least one essentially forward-facing spray nozzle and at least one sideways-facing spray nozzle and which during spraying moves progressively in the direction of the spray front 9 and at the same time rotates about the direction of displacement. Figures 3-5 show an illustrative embodiment of a spray head of this type, which is provided with two essentially forward-facing nozzles and two sideways-facing nozzles.

As can be seen from Figures 3-5, the spray head 6 is essentially cylindrical and is fixed on the end of the lance 7 by means of a screw thread connection 10, via which lance 7 the liquid is fed under a very high pressure of, for example, approximately 1100 bar in order to be sprayed out via the nozzles and sprayed against the explosive under essentially the same pressure.

The liquid fed via the lance 7 enters a distribution chamber 1 1 into which two channels 13, one channel 14 and a channel 16 open. Said channels 13, 14 and 16 lead to nozzles 12, 15 and 17, respectively. The spray head 6 comprises two essentially forward- facing, essentially identical nozzles 12, a sideways-facing nozzle 15 and a sideways-facing nozzle 17. The spraying direction from the nozzles 12 is at an angle α of 15° with respect to the longitudinal axis of the lance 7 or with respect to the direction of movement of the spray head 6, which here comes down to the same thing. The spraying direction of the nozzle 15 is at an angle β of 45° with respect to said longitudinal axis of the lance 7 or the direction of movement of the spray head 6. The spraying direction of the nozzle 17 is at an angle γ of 60° with respect to the longitudinal direction of the lance 7 or the direction of movement of the spray head 6. It will be clear that spray jets directed sideways can also be directed slightly backwards with respect to the direction of movement, in which case the angle β or γ then becomes greater than 90°. In general, however, this will not be necessary. A disadvantage of this can be that the spray jet is relatively easily able to spray directly out of the charge chamber 5 to the outside and is less effective.

The angle between the planes of intersection IV and V in Figure 3 is approximately 60° or 120°, depending on the angle measured.

The diameters of the outflow nozzles are relatively small, in general less than 2 mm, and will usually be in the range of 0.5 to 1.5 mm. In this context the diameters of the outflow nozzles do not have to be in any way identical to one another. A diameter of 0.8 mm for the outflow nozzles 12, a diameter of 1.0 mm for the outflow nozzle 15 and a diameter of 0.7 mm for the outflow nozzle 17 may be mentioned as an example. Taking the angles of the spraying directions of outflow nozzles 15 and 17 into consideration, with these diameters there is approximately an equilibrium of forces as far as the reaction forces acting in the transverse direction of the spray head during spraying are concerned.

Rotating such a spray head 6 provided with a number of nozzles about the longitudinal axis 18 during spraying ensures that the jets issuing from the respective nozzles impinge on the explosive to be removed at all points. In this context a rotational speed of 1 revolution per second has proved very suitable in practice. However, a lower or higher speed of revolution is also conceivable. In view of the very high pressure used when spraying the liquid, higher rotational speeds in particular will result in an adverse contribution to the wear of the bearing for rotating the spray head.

As a consequence of the very high pressures used when spraying the liquid, the spray head 6 will be subject to erosion/wear, especially in the channels leading to the nozzles. In order to extend the tool life of the spray head 6, it is to this end advantageous according to the invention to provide the channels 13, 14 and 16, at least at the orifices thereof, with an erosion- or wear-resistant material, for example tubular inserts made of ruby. Said inserts made of ruby are indicated by 19 and 20 for the nozzles 15 and 17 respectively; however, it will be clear that corresponding inserts will have been provided in the nozzles 12. Figure 6 shows, highly diagrammatically, an installation for removing explosive from ammunition, such as, in particular, grenade bodies, in accordance with the method according to the first aspect of the invention. Said installation, which is also referred to as the spraying installation, comprises a frame 30 in which eight (or optionally more) grenade bodies can be set up and fixed with their longitudinal axis at an angle of approximately 20° with respect to the vertical and with the threaded opening for the detonator or so-called fuse facing downwards. With this arrangement the grenade bodies 1 can be flushed out in step by spraying by means of two spray lances 7, which are provided with a spray head, which is not shown, and which are mounted on a common support movable in a lateral T. With this arrangement, during spraying, the spray lances 7, with the spray heads mounted thereon, are rotatable in the circumferential direction of the lances 7 and are displaceable in the longitudinal direction of the lances 7, so as to be inserted more deeply into the grenade body 1. As is indicated by the lines provided with arrows, the two lances 7 are fed by a high pressure pump 31, which is capable of supplying the water under very high pressure, for example a pressure of 1100 bar. Said water is fed via a filter 32 from a buffer 33 by means of a pump 34. The liquid sprayed via the spray heads 6 is collected, together with the explosive particles which have been detached by spraying, in a collection device 35 in order to be fed from there with the aid of a pump 36 to a separator 37, such as a centrifuge. In the centrifuge 37 the explosive particles which have been detached by spraying are separated off from the water in order then to be discharged and/or stored. The liquid from which explosive particles, in particular the larger explosive particles, have been removed in the centrifuge is fed by means of a pump 38 and via a filter 39 to a storage tank 40, with a capacity of, for example, 30 m³ or more. The water can then be fed from this storage tank 40 by means of a pump 41 and a filter 42 to a buffer 33 for use in the spraying process. As can also be seen from Figure 6, a separate circuit 43 is also connected to the storage tank 40. Said circuit 43 consists of two columns 44, connected in series, having an active charcoal filter, to which liquid can be fed from the storage tank 40 in order to be discharged back to the storage tank 40 after filtering through the active charcoal filter. Explosive particles dissolved in the water, explosive particles emulsified in the water and/or explosive particles dispersed in the water can be removed from the water using such an active charcoal filter, which can also be incorporated elsewhere in the process, such as, for example, at the location of the filters 39, 32 and 42. It is thus possible to prevent a saturation point being reached at which the water would start to foam and would be unsuitable for flushing out explosive by spraying. The storage tank 40 also has the advantage that it offers the possibility for better cooling of the spent liquid during the spraying process before said liquid is re-used for spraying.

It will be clear that the spraying installation shown diagrammatically in Figure 6 has been shown and described merely by way of example and that said installation can be subjected to numerous modifications. Thus, for example, the capacity of the installation, the number of lances, the pressure, etc. can be varied.

Example I The following example with a few parameters is outlined briefly for further illustration:

With TNT as the explosive a maximum production capacity of approximately 300 kg TNT removal per hour can be achieved making use of two simultaneously operating spray heads according to Figures 3-5, a pump pressure/spraying pressure of 1100 bar and a pumping volume of approximately 102.5 litres per minute. With this arrangement the tool life of the spray head in Figures 3-5 is approximately 4 - 6 months. The power required, mainly by the pump, is approximately 200 kW. When flushing out 155 mm grenades by spraying, each grenade containing approximately 6.5 kg TNT as explosive charge, a capacity of approximately 50 grenades per hour can then be achieved with a spray head propulsion speed of approximately 500 to 600 mm per minute and a spray head rotational speed of approximately 1 revolution/second when emptying out by spraying in step 4 x 2 grenades simultaneously, as is shown diagrammatically in Figure 6, and taking account (including in the time) the changing of racks containing grenades between times.

When flushing out 40 mm grenades by spraying, each grenade containing approximately 0.12 kg explosive, a capacity of approximately 80 grenades per hour can then be achieved. With regard to the spraying installation it can also be pointed out that the drive for the spray lances is hydraulic, both in respect of the movement in the longitudinal direction and in respect of the rotary movement. The stroke of the spray lances is limited by means of pneumatic trip valves and will be dependent on the product and can be set to any length between 10 and 750 mm. When the stroke length is set to

750 mm the installation is, for example, suitable for flushing out 8" or 203 mm calibre howitzer grenades by spraying. The linear speed of the spray lance is variable as such and will be approximately 500 mm to 600 mm per minute for flushing out, by spraying, the 150 mm grenade containing poured TNT as explosive charge, which has already been mentioned above. However, said linear propulsion speed of the spray lance will be highly dependent on the type of explosive which has to be sprayed and the diameter or dimensions of the explosive and can only be determined experimentally in practice since the aim must be to flush out the grenade completely in a single operation. The spray lance is brought into rotation by means of a hydraulic motor, the number of revolutions per second being variable between 0.5 and 5 revolutions/second and a speed of revolution of 1 revolution/second having proved highly adequate in practice.

The spraying process has the following safety features: 1. The spraying process is carried out in a bunker built entirely of reinforced concrete and having a so-called brick blow-out wall, which makes it possible to release the pressure in the event of an explosion. The entire flushing out process is operated and controlled from a control room with the use of closed- circuit television, the control of all hydraulic and pneumatic functions being effected by means of PLC units which have been or can be suitably programmed with the aid of a computer.

2. Pressure protection against too high and too low a pressure by means of sensors on both the pumping installation itself, which sensors ensure that the spraying process is stopped immediately if the pressure falls below or exceeds a set pressure.

3. The linear movement of the spray lance is protected in the event of obstruction by means of a sensor which in the event of a 10% rise in peak pressure in the hydraulic system transmits a signal to a hydraulic/magnetic protection unit which switches off the entire spraying installation and immediately stops the spraying operation.

4. The foreman in charge of the spraying process can follow the entire process on a television screen and can stop the entire process by means of an emergency stop button it he considers this to be necessary.

5. When the system is switched off, especially also when it is switched off as a consequence of a safety feature being activated, the spray lances will preferably be returned to a starting position.

The second aspect of the invention will be explained in more detail below. In this context, as far as the figures are concerned, reference will be made mainly to Figures 7, 8 and 9. The second aspect of the invention relates to the processing of explosive waste, such as, for example, explosive waste obtained in accordance with the first aspect of the invention, but also other explosive waste.

In order to render the explosive waste suitable for further treatment, further transport and/or storage, it is processed according to the invention to give a stable suspension or emulsion in an inert aqueous medium, in particular water, by adding one or more thickeners and/or emulsifiers. Such a stable suspension or emulsion will be referred to below by the general term "slurry".

Before adding one or more thickeners or emulsifiers, the explosive will, if necessary, first be mixed with a liquid, in particular water. In the case of the flushing out process according to the first aspect of the invention, the mixture of sprayed liquid and explosive particles entrained therein can also be processed directly to give a stable slurry. If desired, additional liquid, in particular water, can optionally be added in order to ensure that the percentage by weight of explosive does not exceed a certain value, in general 50%, and more preferentially 40%.

According to the invention, the mixture of liquid, such as water, and explosive, which mixture can be regarded as explosive waste, can in particular be processed to give a stable slurry if, in a first step, an organic thickener or emulsifier, in particular based on cellulose or starch, is added up to a content, determined by testing, of preferably approximately 2 to 4% by wt. When a thickener or emulsifier based on cellulose is used, such a stabilised suspension can easily be kept in a stable condition for 1 week, that is to say without substantial demixing taking place. According to the invention, the stable condition, during which no substantial demixing takes place, can easily be extended to 3 weeks and even to 3 months or more by, in a second step following the first step, adding an inorganic thickener or emulsifier, in particular water-glass, to the already pre-stabilised slurry up to a proportion by weight, determined by testing, of preferably approximately 2 to 4%.

Settling out of explosive particles is counteracted and pumpability of the stabilised slurry is appreciably promoted if the particle size of the explosive present in the slurry is less than approximately 10 mm, in particular less than or equal to approximately 5 mm. Preferably, it is ensured that the explosive already complies with said value for the particle size before the one or more thickeners and/or emulsifiers .are added. Optionally this can also be ensured in an after-treatment by subjecting the slurry to a process in which the larger particles are still broken down into smaller particles at this stage, for example, by means of stirrers.

Example II

A stable suspension or emulsion containing: - 50% by wt TNT

50% by wt water, organic thickener/emulsifier and inorganic thickener/emulsifier, with at least 40% by wt water, 1 to 4% by wt organic thickener/emulsifier and no more than 6% by wt inorganic thickener/emulsifier was made in accordance with the invention. The organic thickener/emulsifier used was carboxymethylcellulose and the inorganic thickener/emulsifier used was silicon dioxide.

The silicon dioxide used was silicon dioxide produced by Degussa AG, Germany, marketed under the registered trade name AEROSIL, of the OX50 type, designated in short form as Aerosil OX50. This silicon dioxide had a so-called BET surface area of 50 ±

15 m²/g according to DIN 66131 and an average particle size (so-called average primary particle size) of 40 mm and an Si0₂ content of greater than 99.8%.

Suspensions obtained in this way were found to be very stable in the long term and in general to have a viscosity which makes the suspension readily pumpable. Furthermore, such suspensions/emulsions .are found to render the explosive so highly inert that the emulsion/suspension may (taking account of statutory regulations) and can be handled, stored and transported as non-explosive.

The inertness of the emulsion/suspension has been extensively tested for an emulsion/suspension consisting of approximately 50% by wt TNT, approximately 42% by wt water, approximately 5% by wt of the abovementioned silicon dioxide obtained from Degussa AG (Aerosil OX50) and 3% by wt carboxymethylcellulose. With regard to the test report on said emulsion/suspension reference is made to the draft TNO report entitled "Safety testing of TNT slurry", report no. ML1998-C93, November 1998, by N.H.A. van Ham and E.G. de Jong which has been submitted as an enclosure with the application. The 50% TNT and 50% water mentioned in the third paragraph on page 1 must read the mixture of 50% by wt TNT, 42% by wt water, 5% by wt of the silicon dioxide obtained from Degussa and 3% by wt carboxymethylcellulose, which has just been mentioned and which was the slurry actually tested in said report.

It can be seen from the abovementioned draft TNO test report that such an emulsion/suspension can be processed safely, can be transported safely and can be stored safely. It can clearly be seen that it is very difficult to detonate the slurry (emulsion/ suspension) and that once the slurry has been detonated no propagation reaction is discernible. The mixture tested has also proved to be stable for more than 5 months already.

The abovementioned draft TNO report entitled "Safety testing of TNT slurry" included with the application as an enclosure is incorporated in this patent application by reference.

According to the invention it is found that the slurry containing explosive particles which has been stabilised in this way, but also other slurries containing explosive particles, can be surprisingly well incinerated in an incinerator at a temperature of between 300 °C and 2000 °C, with excess oxygen. This is possible because a slurry containing explosive particles, in particular a stabilised slurry containing explosive particles, can be fed in a highly controlled and readily controllable manner to the incinerator with the aid of one or more pumps and a suitable metering device. It is found, in particular, that the incineration can be carried out safely as a two-step incineration, the slurry containing explosive particles being fed to the incinerator at a temperature of approximately 400 °C to 800 °C, preferably approximately 400 °C to 600 °C, with a slight excess of oxygen. The slurry decomposes very rapidly, virtually instantaneously, in such a medium into decomposition products which are not explosive or are barely explosive. Said decomposition products are then incinerated in a second step at a higher temperature, preferably in the range from 800 °C to 1200 °C, such as, for example, approximately 1000 °C, with a substantial excess of oxygen. The residual incineration products can then be further treated using conventional flue gas treatment means known per se, in order to be able to discharge the clean flue gas into the environment via a chimney. It is found that the combustion can be effected in a particularly advantageous manner by making use of a fluidised bed, that is to say by using a so-called fluidised bed furnace. In this case the bed consists of sand, in particular river sand, that is pre-heated to the temperature desired for the first incineration step before feeding slurry to the incinerator. When the bed has reached the desired temperature, the slurry is introduced, preferably dropwise in order to prevent the risk of explosion, into the bed, in particular into the heart of the fluidised bed, in order rapidly to be decomposed in said bed into relatively non-hazardous decomposition products.

An installation for carrying out the method according to the invention is shown here diagrammatically in Figure 7. Said incinerator consists of a fluidised bed furnace 100. The bed 101 of river sand is pre-heated by means of a starter burner 102 operating on a mixture of natural gas, supplied via 103, and heated air, supplied via 104 and/or 105. During this operation the bed is also brought into the fluidised state by means of hot air. When the bed in the fluidised state has reached the temperature of preferably approximately 400 °C to 600 °C desired for the first step, slurry is fed into the bed by means of a metering system indicated highly diagrammatically in Figure 7 by a straight, horizontal arrow 106. By using combustion air to bring the bed into movement it is possible to achieve a relatively low excess of oxygen. After the slurry has been decomposed to decomposition products in the bed 101, the decomposition products are transported further upwards in the furnace to a hotter region for incineration with the secondary air supplied at 107 in a higher excess of oxygen in the second, hotter step 108. The incineration products are then discharged from the furnace at 109 and fed to a water-cooled cyclone 110 to separate off solid particles at 111, after which the residual combustion gases are fed through a heat exchanger 112 to preheat air and are then fed through a cloth filter 113 and, with the aid of a fan 114, are fed to the chimney 115 for discharge of the residual gases into the environment. It will be clear that the after-treatment of gases issuing from the furnace 100 can be carried out in numerous ways known from the prior art, which can also deviate from what has been outlined here.

Figure 8 shows, highly diagrammatically, a metering system for metering slurry containing explosive particles into an incinerator, such as the incinerator in Figure 7. The slurry to be metered is stored in a reservoir 130 which can be provided with a stirrer, which is not shown, and to which a discharge line 132 having a peristaltic pump 131 therein is connected, so that slurry can be fed via the line 133, which joins line 132, to an injector 150. Two return branches 134 and 135, respectively, with a controllable valve 137 and 136, respectively, incorporated therein also join onto line 132, via which return lines 134 and 135 slurry can be returned to the reservoir 130. In this way the slurry in the reservoir 130 can be kept in motion, supplementing any stirring means contained therein, which are not shown, in order to counteract precipitation of, or separating out of explosive particles from the slurry. A water feed 139, to be operated via valve 138, also joins onto line 133, by means of which water feed 139 water can be supplied to the slurry in the reservoir or water can be added to the slurry fed to the injector 150, depending on whether the circumstances require this and on whether the positions of the various valves 136, 137, 140, 141 and 142 and the lines allow this. The supply of water to the slurry reservoir or to the slurry fed to the injector can, for example, be desirable if the percentage by weight of explosive in the slurry is too high. In general, a percentage by weight of approximately 40% explosive particles is considered to be desirable.

Two valves, that is to say valves 141 and 142, are incorporated downstream of one another in the line 133 which leads to the injector 150. 142 is a non-return valve which prevents back- flow through line 133 in the direction of the reservoir in order to be able to counteract the effect of pressure waves originating from the furnace reaching into the reservoir. Such pressure waves can, for example, occur in the event of disasters, such as explosions, and do not per se have to originate in the furnace itself but could also be produced in the injector 150 or at another location downstream of valve 142. Valve 141 is an emergency shut-off valve, which can be automatically closed in the event of disasters in order to prevent the supply of slurry, and thus also of explosive particles, to the incinerator. Valve 141 and valve 142 can optionally be integrated in a single valve. The flow of slurry through line 133 to the injector 150 can be controlled by means of valve 140.

Compressed air can be supplied to the injector, which is of the compressed air type, via line 148. A non-return valve 145, which must prevent pressure waves in the direction of the compressed air source, is incorporated in line 148 and a control valve 146 for controlling the compressed air supply is located further upstream of the non-return valve 145. A buffer vessel 147 for compressed air, the purpose of which is to be able to even out pressure variations in the compressed air line, is also attached to line 148.

At the orifice 151 of line 133, the slurry is entrained dropwise under the influence of the compressed air supplied via line 148 into the incinerator via the injector 150. The injector essentially consists of a pipe, the jacket of which is cooled by means of cooling water supplied via line 152 and discharged via line 153.

Line 133 preferably consists of a plastic hose, which has the advantage that this is able to absorb pressure waves as a result of the flexibility of the hose and that, in the event of an emergency, the hose will be able to burst at a certain pressure, such as, for example, a bursting pressure of 7 bar, which is beneficial for safety in the event of disasters. Such a hose can also automatically detach in the event of disasters.

To protect the entire system, the emergency safety valve 141 can be closed, for example, when: - one of the safety features of the fluidised bed furnace is triggered, the flow rate of natural gas for the burners falls below a specific minimum value, the stirrer in the reservoir or the circulation system via branches 134 and 135 has failed, the level in the pump casing is too high, - the delivery pressure of the peristaltic pump 131 is too high, the pressure of the compressed air is too low, the compressed air flow rate is too low, the temperature of the injector becomes too high.

Since the flow rates of slurry through the line 133 are relatively low and the quantity of slurry passing through line 133 is relatively small, it is relatively difficult to measure the quantity of slurry discharged from the reservoir by means of a flowmeter. For this reason the reservoir 130 is placed on a weighing device, so that the stock of slurry contained in the reservoir can be determined and monitored by determining the weight.

The third aspect of the invention will be explained in more detail below with reference to Figures 9, 10 and 11 by way of illustration by means of a preferred embodiment.

Figure 9 shows a grenade body 1 in the upright position, which grenade body encloses an explosive charge chamber 5. The grenade body 1 is, for example, the body of a so-called 155 mm grenade. The grenade body 1 is provided at the front, the top in Figure 9, with a bore 2 having a screw thread, into which the detonator or so-called fuse can be screwed tight.

The grenade body 1 shown in Figure 9 is a grenade body of the type that in principle is used for live ammunition. The difference is that either the grenade body 1 has never been filled with an explosive charge or that the explosive charge has been removed from the charge chamber 5 in the grenade body 1, for example in accordance with the method corresponding to the first aspect of the invention.

A particular embodiment of the third aspect of the present invention is to make such a grenade body originally intended for live ammunition into blank ammunition. To this end the grenade body 1 is placed on a weighing device, after which granular material, in particular gravel having a particle size of preferably 2 to 4 mm, is introduced via the bore 2 into the charge chamber 5 until the weight of the grenade body 1 and the quantity of gravel introduced together has a specific predetermined value. A foamable material, in particular PUR foam, preferably based on a polyurethane high-resistance foam system, is then introduced into the charge chamber 5, for example by means of injection, by means of an injection pipe 200. To this end the injection pipe 200 can already have been inserted in the charge chamber 5 to a desired depth, preferably as far as the base 8, before the granular material or gravel is introduced. Injection of the PUR foam then takes place from the bottom into the charge chamber 5, so that the foaming PUR foam entrains the granular material 201 or gravel 201 and carries it upwards and, on curing, encapsulates said material 201. In order to obtain as optimum and as uniform as possible a homogeneity and uniformity of the weight distribution of the inert mass consisting of granular material/gravel and PUR foam in the end product, it is advantageous gradually to withdraw the injection pipe 200 upwards during injection, so that the PUR foam is introduced in a distributed manner into the charge chamber 5 on injection and the granular material or gravel is incorporated uniformly distributed therein. In this context the use of a polyurethane high- resistance foam system is to be preferred since this offers adequate resistance against deformation when the blank ammunition is fired, during which forces greater than 10,000 g are customary.

In order to obtain a final weight of the blank grenade formed which is as close as possible to a certain desired constant value, according to the invention the quantity of PUR foam injected is kept constant irrespective of the quantity/the weight of granular material gravel introduced. After the PUR foam has been injected and the injection pipe 200 has been completely withdrawn from the grenade body, the grenade body is closed by means of a plug 202 which can be screwed into the passage 2 provided with a screw thread. The plug 202 is provided with a passageway, which is not shown, which is so sized that moisture, air, gas and surplus foam are able to escape from the charge chamber 5 under the influence of the expansion of the foam during foaming and curing. Since the foam has a very low relative density in the expanded state, the weight of foam which escapes via the plug 202 will have relatively little effect on the total weight of the blank grenade.

In order to be able to provide the blank grenade with a conventional, or optionally special, detonator or so-called fuse, the plug 202 is provided with an extension body 203, such that after curing and removal of the plug 202 a cavity 204 remains in the top of the inert fill mass (consisting of foam and granular material 201), in which cavity the detonator or so-called fuse can be accommodated.

Claims

1. Method for processing explosive waste to give a stable suspension or emulsion in an inert aqueous medium, in particular water, by adding one or more thickeners and/or emulsifiers, wherein one of the thickeners and/or emulsifiers is organic, characterised in that an inorganic thickener and/or emulsifier is also used.

2. Method according to Claim 1, characterised in that an organic thickener and/or emulsifier and an inorganic thickener and/or emulsifier are added in succession.

3. Method according to Claim 1 or 2, characterised in that the organic thickener or emulsifier is added to give a proportion by weight of less than approximately 10%, preferably less than approximately 6% and more preferentially approximately 1% to 4%.

4. Method according to one of the preceding claims, characterised in that the organic thickener or emulsifier is a thickener or emulsifier based on cellulose or starch, such as carboxymethylcellulose added to give a proportion by weight of, for example, 1% to 5%.

5. Method according to one of the preceding Claims 2-4, characterised in that the inorganic thickener or emulsifier is added to give a proportion by weight of less than approximately 10%, preferably less than approximately 6% and more preferentially approximately 1% to 4%.

6. Method according to one of the preceding claims, characterised in that the inorganic thickener or emulsifier is a polymer based on silicon, in particular water-glass or silicon dioxide.

7. Method according to one of the preceding claims, characterised in that the inorganic thickener has a particle size of less than 10 ╬╝m, preferably less than 0.1 ╬╝m.

8. Method according to one of the preceding claims, characterised in that the average particle size of the inorganic thickener and/or emulsifier is in the range from 10 nm to 1000 nm, preferably 10 nm to 100 nm, such as approximately 40 nm.

9. Method according to one of the preceding claims, characterised in that the inorganic thickener has a specific surface area (so-called BET surface area) in the range from 0.1 to 200 m²/g, preferably in the range from 1 - 80 m²/g and more preferentially in the range from 10 to 70 m²/g, such as approximately 50 ┬▒ 15 m²/g.

10. Method according to Claim 9, characterised in that the specific surface area has been determined in accordance with DIN 66131.

11. Method according to one of the preceding claims, characterised in that the thickened final mixture contains no more than approximately 70% by wt, preferably no more than approximately 50% by wt, explosive.

12. Method according to one of the preceding claims, characterised in that the particle size of the explosive is less than approximately 6 mm, preferably less than or equal to approximately 5 mm and in particular less than or equal to 3 mm.

13. Stabilised mixture obtained or as can be obtained in accordance with one of Claims 1-12.

14. Method for processing explosive waste, characterised in that an emulsion or suspension containing explosive waste, which has preferably been obtained in accordance with the method according to one of Claims 1-12, is incinerated in an incinerator at a temperature in a range which runs from approximately 300 to 400 ┬░C to approximately 1400 ┬░C to 1500 ┬░C, with an excess of oxygen.

15. Method according to Claim 14, characterised in that the incineration is earned out as a two-step incineration, wherein the first step is ca╧Çied out at a temperature of approximately 400 - 800 ┬░C, preferably approximately 400 - 600 ┬░C, with a slight excess of oxygen, and the second step is carried out with a substantial excess of oxygen at a temperature of approximately 800 - 1200 ┬░C, preferably at approximately 1000 ┬░C.

16. Method according to one of Claims 14-15, characterised in that the incinerator comprises a fluidised bed furnace in which at least the first step of the incineration takes place.

17. Method according to Claim 16, characterised in that the bed is a sand bed, such as a bed comprising river sand.

18. Method according to Claim 16 or 17, characterised in that the emulsion or suspension is introduced into the heart of the fluidised bed in the furnace.

19. Method according to one of Claims 14-18, characterised in that the emulsion or suspension is brought into droplet form and is fed in droplet form to the incineration process, in particular the first step thereof.

20. Method according to one of Claims 14-19, characterised in that the emulsion or suspension is fed to the incinerator by means of a peristaltic pump.

21. Method according to one of Claims 14-20, characterised in that the emulsion or suspension is injected into the incinerator via an injector tube, preferably of the compressed air type, and in that the injector tube is cooled.

22. Method according to Claim 21, characterised in that the injector tube or the emulsion/suspension feed thereof is provided with a non-return valve which closes in the event of flash-back from the incinerator.

23. Method according to one of Claims 14-22, characterised in that a shut-off valve, which can be integrated with the non-return valve according to Claim 22, is fitted in the emulsion or suspension feed to the incinerator, which shut-off valve is closed in the event of a "disaster", such as an explosion, pressure in excess of a limit, excessively high temperature, etc., in the incinerator.

24. Incinerator, in particular fluidised bed furnace, suitable for carrying out the method according to one of Claims 14-23.

25. Injector tube suitable for carrying out the method according to one of Claims 21-23.

26. Method for removing explosive from ammunition or ammunition components, wherein the explosive is flushed out of the ammunition with the aid of an essentially inert liquid, such as water, under high pressure.

27. Method according to Claim 26, wherein the liquid pressure is higher than 400 to 500 bar, preferably higher than 700 bar.

28. Method according to Claim 26 or 27, wherein the liquid pressure is less than 20% of the initiation pressure of the explosive to be removed and wherein the liquid pressure is preferably no higher than 1500 to 2000 bar.

29. Method according to one of the preceding Claims 26-28, wherein the liquid pressure is in the range from 800 to 1500 bar, for example approximately 1100 bar.

30. Method according to one of the preceding Claims 26-29, wherein a spray head provided with one or more nozzles is used for spraying the liquid, which spray head is moved continuously or stepwise, during spraying, in the direction of the explosive at a speed such that as spraying progresses it is always ensured that that portion of the explosive located in front of and/or around the spray head is flushed away.

31. Method according to one of the preceding Claims 26-30, wherein the ammunition or the ammunition component comprises a body, such as a grenade body, having a chamber containing explosive therein, wherein the body has an opening from said chamber to the outside, such as the opening for introduction and/or fixing of the detonator or so-called fuse, wherein the body is set up with the opening facing downwards during spraying, wherein the liquid is sprayed via a spray head provided with one or more nozzles and wherein, during spraying, the spray head is inserted into and/or through the opening from underneath in an upwards direction in order to be able to flush the explosive out of the chamber on spraying.

32. Method according to Claim 31, wherein the spray head, during spraying, is moved upwards in said chamber, stepwise or continuously, at a speed such that explosive has been completely (or at least virtually completely) removed from the portion of the chamber which is located under the spray head.

33. Method according to Claim 32, wherein the upwards speed of the spray head is in the range from 200 to 1000 mm per minute.

34. Method according to one of Claims 30-33, wherein the spray head is rotated during spraying.

35. Method according to Claim 34, wherein the rotational speed of the spray head is in the range of 0.3 to 10 revolutions/second, such as 0.5 to 5 revolutions/second.

36. Method according to one of Claims 32-35, wherein the spray head is provided with at least one nozzle directed essentially forwards and at least one nozzle directed sideways or obliquely sideways.

37. Method according to one of Claims 26-36, wherein the liquid used for spraying, with particles of explosive contained therein, is collected and fed to a separator, such as a centrifuge, in order to separate off the particles of explosive from the liquid, after which the liquid is re-used for flushing out explosive by spraying.

38. Method according to Claim 37, wherein the liquid issuing from the separator is fed to a reservoir for interim storage.

39. Method according to Claim 37 or 38, wherein the liquid is fed through a charcoal filter, preferably downstream of the separator and before it is sprayed again.

40. Method according to Claim 37 or 38, wherein the liquid is fed from the reservoir through a charcoal filter and is fed back into the reservoir again.

41. Equipment for use of the method according to one of Claims 26-40.

42. Spray head, in particular for carrying out the method according to one of Claims 26-40, comprising a spray head body, provided with a multiplicity of nozzles, suitable for fitting on a spray lance, wherein the spray head has a longitudinal axis extending in the extension of the spray lance, characterised in that the spray head has one or more nozzles, preferably arranged symmetrically with respect to the longitudinal axis and directed sideways with respect to the longitudinal axis, wherein the nozzles are preferably directed such that the reaction forces acting on the spray head in the transverse direction during spraying compensate for one another, or at least essentially compensate for one another.

43. Spray head according to Claim 42, characterised in that the angle of the spray direction(s) of the nozzles directed essentially forwards is in the range from approximately

0┬░ to approximately 30┬░ with respect to the longitudinal axis.

44. Spray head according to Claim 42 or 43, characterised in that the angle of the spray direction(s) of the nozzles directed sideways is in the range from approximately 40┬░ to approximately 140┬░, preferably in the range from approximately 40┬░ to approximately 90┬░, with respect to the longitudinal axis, measured from the front of the spray head facing away from the spray lance.

45. Spray head according to one of Claims 42-44, characterised in that the walls of the channels to the nozzles, at least at the nozzle ends thereof, are coated with or are constructed with an erosion- or wear-resistant material which preferably has a Mohs hardness of at least 9, such as a natural or synthetic precious stone, for example ruby.

46. Installation for removing explosive from ammunition, comprising: one or more spray lances having a spray head preferably according to one of Claims

42-45. pressure means for pressurising a liquid, such as water, to at least 500 bar, preferably at least 800 to 900 bar, and feeding said liquid to the spray lances, frame sections for holding the ammunition in place, moving means for inserting each of the spray lances in the longitudinal direction of the spray lances into an ammunition component, collection means for collecting sprayed liquid and explosive particles, detached by spraying, originating from the ammunition which has been flushed out by spraying.

47. Installation according to Claim 46, comprising separating means for separating off from the liquid explosive particles entrained therein.

48. Installation according to Claim 46 or 47, comprising filtering means, preferably an (active) charcoal filter, for separating off from the liquid explosive emulsified, dispersed or dissolved therein.

49. Installation according to one of Claims 46-48, comprising a reservoir positioned between the separating means and the pressure means.

50. Installation according to Claims 48 and 49, wherein the filtering means are incorporated in a separate circuit starting and ending at the reservoir, in which circuit pumping means are also provided which can be operated independently of whether or not spraying is being carried out.

51. Method for the production of blank ammunition, wherein a charge chamber in a body, such as a grenade body, is filled with an inert mass, characterised in that the inert mass consists of a component system of at least two components, the one component of which is a relatively heavier component having a higher relative density and the other component of which is a relatively lighter component having a lower relative density, and in that the ratio of the components is preferably so chosen that the relative density of the component system is matched to the desired ballistics characteristics of the blank ammunition and the weight distribution of the component system is made uniform.

52. Method according to Claim 51, characterised in that the grenade body is a conventional grenade body, in that the charge chamber is the explosive chamber intended for explosive, which chamber is filled with the inert component system instead of with explosive, in that the relative density of the lighter component is lower than the relative density of the explosive, in that the relative density of the heavier component is higher than the relative density of the explosive and in that the ratio of the components of the component system is so chosen that the relative density of the component system is essentially equal to that of the explosive.

53. Method according to Claim 51 or 52, characterised in that a foamable material is used for the lighter component, which foamable material is injected in liquid form into the charge chamber and is allowed to foam and cure in the charge chamber, and in that a granular material is used for the heavier component.

54. Method according to Claim 53, characterised in that the granular material and the foamable material in combination are so chosen that the granular material can be entrained by the foamable material during foaming and is fixed in the foamable material during curing.

55. Method according to Claim 53 or 54, characterised in that a PUR foam is used for the foamable material.

56. Method according to one of the preceding Claims 51-55, characterised in that a gravel is used for the heavier component.

57. Method according to one of Claims 53-55 or 56, characterised in that the granular material or the gravel has a particle size of less than 8 mm.

58. Method according to one of Claims 53-57, characterised in that the spread in the particle size of the granular material or of the gravel is less than 3 mm.

59. Method according to one of Claims 53-58, characterised in that the granular material or the gravel has a particle size which is in the range from 2 mm to 4 mm.

60. Method according to one of the preceding Claims 51-59, characterised in that the empty (grenade) body is weighed and in that the quantities of the components of the component system which are to be used are then determined such that the total weight of the empty (grenade) body and of the quantities of the components to be used is essentially equal to a predetermined value.

61. Method according to one of Claims 52-59 in combination with at least Claim 52 and Claim 53, wherein the grenade body is weighed and the charge chamber thereof is then filled with a quantity of granular material which has been chosen such that the total weight of the grenade body and the granular material has a predetermined value, wherein, after said filling with granular material, an injection nozzle is inserted in the charge chamber of the grenade body, which is preferably set up vertically, in order to inject the foamable material into the charge chamber via said injection nozzle.

62. Method according to Claim 61, wherein the injection of foamable material takes place while the injection nozzle is moved stepwise or continuously from the bottom upwards.

63. Method according to Claim 61 or 62, wherein the quantity of foamable material is a predetermined fixed quantity.

64. Method according to one of Claims 61-63, wherein the charge chamber of the grenade body is closed off at the top by a plug, in particular a screw plug, which is provided with a passageway which is so sized that the granular material is retained and air and foamable material are allowed to pass through.

65. Method for the production of blank ammunition, wherein the explosive in a conventional grenade body filled with explosive is removed from the explosive chamber of the grenade body, preferably in accordance with the method according to one of Claims 26-40, and wherein the grenade body from which the explosive has been removed is then used for the production of blank ammunition according to one of Claims 51-64.

66. Grenade body and blank ammunition obtained using the method according to one of Claims 51-65.

67. Grenade body for blank ammunition having a charge chamber filled with inert mass, characterised in that the inert mass consists of a component system of at least two components, the one component of which is a relatively heavier component having a higher relative density and the other component of which is a relatively lighter component having a lower relative density.

68. Grenade body according to Claim 67, characterised in that the grenade body is a conventional grenade body, in that the charge chamber is the explosive chamber thereof intended for explosive, in that the relative density of the lighter component is lower than that of the explosive and in that the relative density of the heavier component is higher than the relative density of the explosive.

69. Grenade body according to one of Claims 67-68, characterised in that the lighter component is a foamable material which has been introduced in liquid form into the charge chamber and has been foamed and cured therein and in that the heavier component is a granular material.

70. Grenade body according to Claim 69, characterised in that the foamable material is a PUR foam.

71. Grenade body according to one of Claims 61-70, characterised in that the heavier component is gravel.

72. Blank ammunition comprising a grenade body according to one of Claims 67-71.