OA20765A - Installation for the preparation of an explosive composition and process for the preparation of an explosive composition. - Google Patents

Abstract

The present invention relates to an installation for the preparation of an explosive composition in the form of cartridges and to a process for the preparation of an explosive composition. More specifically, the installation according to the present invention comprises: - a first hopper intended to contain ammonium nitrate in the form of prills and connected to an inlet end of a screw feeder - a means of injecting an inverse emulsion comprising nitrate, placed close to an outlet end of the screw feeder, - a vertical tubular element, one inlet end of which is connected to the outlet end of the screw feeder and one outlet end is connected to an inlet end of a screw mixer - a second hopper intended to contain small-sized hollow bodies connected to the vertical tubular element via a means for injecting small-sized hollow bodies arranged close to the outlet end of said vertical element.

Description

Description

Title of the invention: Installation for the preparation of an explosive composition and process for the preparation of an explosive composition

Technical area

The present invention relates to the field of preparation and setting covers;. key explosive products including c. explosive compositions used damsA'S; cm the raw material extraction and mining industry. ' ^j

The present invention relates to an installation for the preparation of an explosive composition from a cold inverse emulsion and a process for the preparation of an explosive composition in particular using an installation according to the invention.

Prior technique

Explosive compositions are conventionally made from a so-called inverse base emulsion or "water in oil" obtained by mixing an oily continuous phase, consisting of a mixture of various fuels such as a vegetable fat or mineral and a discontinuous aqueous phase consisting of various oxidizing salts in aqueous solution.

The oxidizing raw materials most frequently used in this industry are: ammonium nitrate, sodium nitrate, calcium nitrate, your fuels can for example be pure diesel or mixed with new or used mineral oils, such as than recycled motor oil.

To give this mixture improved detonation characteristics, it does so in a known manner, dispersing “porosities” in its sound in a homogeneous manner. The sensitization of emulsions by the dispersion of these porosities is generally carried out by chemical gasification, which consists of generating gas bubbles homogeneously in the emulsion. This sensitivity can also be achieved by the dispersion within the emulsion of small hollow bodies, the size of which is between a few tens and a few hundreds of microns, such as glass microbeads, thermoplastic polymer beads or expanded polystyrene.

In the context of the present invention, the term “matrix” or “emulsion” is understood to mean the inverse emulsion in which hollow bodies of small size are dispersed.

The preparation of explosive compositions is generally carried out hot, typically at temperatures between 80 and 90 degrees Celsius in order to allow in particular the good dispersion of the porosities, such as gas bubbles but especially small hollow bodies, within the matrix and to ensure that a homogeneous explosive composition is obtained and thus has good pyrotechnic properties. However, the preparation of these hot explosive compositions requires the implementation of complex, expensive and bulky installations. These compositions are therefore generally prepared well in advance of their implementation, in the form of bulk compositions or packaged in cartridges, then transported to the point of interest intended for the implementation of the explosive composition.

The transport of these compositions, often carried out over long or even very long distances, requires the implementation of heavy and costly logistics to secure the transport and to prevent any explosive risk. In addition, after this journey the pyrotechnic properties of the composition may be altered. Thus, the preparation of these compositions and their transport with a view to their use are complex, long, expensive and present certain dangers.

There is therefore a need for solutions making it possible to avoid the transport of the explosive composition and the cumbersome logistics relating thereto. In other words, it is necessary to have a solution for preparing the explosive composition near the site of implementation of the composition. For this purpose, it is necessary to have facilities for the preparation of explosive compositions which are small in size, tacitly emplaced and transported.

Transportable modular installations have been proposed in the prior art to produce an explosive composition directly on the implementation site. For example, reference can be made to the installations described in your patent documents US4526633 and GB2126910. These documents describe small mobile installations in the form of a truck comprising a platform supporting storage tanks for the aqueous phase and the oily phase for the preparation of the inverse emulsion and means for manufacturing the explosive on site by mixing said phases .

More specifically, the document US4526633 describes a system for the manufacture, in bulk on site and the distribution of an explosive composition, said system comprising a mobile base on which is housed a container for a sr / ution of oxidizing salt, a container for an emulsifier solution and organic liquid fuel or individual containers for each ingredient; means for combining the oxidizer salt solution, the emulsifier and the liquid organic fuel to form a fluid mixture thereof; a mixer for mixing the fluid mixture of oxidizer salt solution, emulsifier and liquid organic fuel to form a water-in-oil emulsion phase; a container for a particulate dry ingredient or ingredients; means for adding the dry particulate ingredient or ingredients within the mixed water-in-oil emulsion phase; a mixer for mixing the dry particulate ingredients uniformly within the water-in-oil emulsion phase to form an explosive composition; means for delivering said composition from the mixer; and a conduit through which the explosive composition can be delivered into a borehole or other receptacle,

Document GB2126910 describes a mobile device for preparing an explosive composition comprising at least one static mixer intended to mix the components of a liquid explosive, said device being mounted in a vehicle. The vehicle may be a truck, and the device may include a placement pump on the truck for pumping the explosive composition from the static mixer into a hole, and storage tanks on the truck for the oxidant component and the combustible component, each of which fesen /oir is provided with a discharge pump to pump the associated component at a desired flow rate and pressure to the static mixer. The device may also include means downstream of the static mixer for mixing with the composition with a sensitizer such as minerals or gas bubbles.

Finally, these facilities are intended to prepare and deposit directly on site, in particular in a borehole, an explosive composition for its direct use.

Thus, these installations are not suitable for the production of an explosive composition which is stable over time and which can be packaged, for example, in the form of a cartridge with a view to subsequent use, in particular elsewhere than in a borehole.

There is therefore a need to have an installation for the preparation of an explosive composition which is of measured size, not very complex, easy to install, to dismantle and to transport so as to be able to prepare under secure conditions, an explosive composition which is stable over time, and which can be packaged in the form of cartridges for subsequent use near the preparation site.

There is also a need to have a process for preparing an explosive composition which is simple, rapid, inexpensive, safe, easy to implement close to the site of implementation of the composition and which makes it possible to obtain an explosive composition with good pyrotechnic characteristics and stable over time.

To this end, the present invention advantageously provides an installation for the preparation of an explosive composition and a method for preparing an explosive composition meeting the existing needs mentioned above.

The Applicant realized that it was possible to have an installation for the preparation of an explosive composition, which is of measured size, not very complex, easy to install, to dismantle and to transport so as to be able to prepare in a secure manner an explosive composition in the form of cartridges which is stable over time and which can be packaged for subsequent use, by developing an installation making it possible to prepare the composition cold and more particularly at a temperature between 20 and 50 degrees Celsius.

Disclosure of Invention

A first object of the invention relates to an installation for the preparation of an explosive composition comprising:

- a first hopper (1) intended to contain ammonium nitrate in the form of prills and connected to an inlet end (2) of a screw feeder (3),

- a means of injecting an inverse emulsion (4) comprising nitrate, arranged close to an outlet end (5) of the screw feeder (3),

- a vertical tubular element (6), one end of which (7) is connected to the outlet end (5) of the screw feeder (3) and one outlet end (8) is connected to one end input (9) of a screw mixer (10) and

- a second hopper (11) intended to contain small-sized hollow bodies connected to the vertical tubular element (6) via a means (12) for injecting small-sized hollow bodies disposed close to the outlet end (8) of said vertical element (6).

A second object of the invention relates to a method for preparing an explosive composition in which successively,

- a dose of ammonium nitrate in the form of prills is premixed with a dose of inverse emulsion comprising nitrate to form a premix,

- the premix passes through a vertical tubular element (6) towards an outlet end (7) of said element,

- a dose of small hollow bodies is injected into the vertical tubular element (6) close to the outlet end (8) of said element and before the premix reaches the outlet end (8) of the vertical tubular element (6), so as to form an inhomogeneous mixture,

- the inhomogeneous mixture formed at the exit end (8) of the tubular element (6) is released into a screw mixer (10), so as to form a homogeneous mixture corresponding to the explosive composition.

A third object of the invention relates to an explosive composition comprising ammonium nitrate in the form of prills, an inverse emulsion comprising nitrate and small-sized hollow bodies, packaged in the form of cartridges from to 90 mm in diameter, characterized in that that it has a detonation velocity of 4000 - 5000 m/s in free air.

Brief description of the drawings

[Fig. 1] Figure 1 shows a perspective view of the installation according to the invention, in which there is a first hopper (1) intended to contain ammonium nitrate in the form of prills and connected to an inlet end (2) of a screw feeder (3), a means for injecting a reverse emulsion ter; disposed close to an outlet end (5) of the screw feeder, 1.:0 etemsr.macular vertical (6) of which an inlet end (7) is connected to the outlet end of the screw feeder (3) and an outlet end (8) is connected to an inlet end (9) of a screw mixer (10), a second hopper (11) intended to contain small-sized hollow bodies connected to the vertical tubular element (6) via a means (12) for injecting small-sized hollow bodies placed near from the outlet end (8) of said vertical element (6), a third hopper (13) capable of recovering the explosive composition, connected to an outlet end (14) of the screw mixer (10), which a third hopper (13) is connected to a metering pump (15) itself connected to a clipper (16).

Detailed description of the invention

Thus a first object of the invention relates to an installation for the preparation of an explosive composition comprising:

- a first hopper (1) intended to contain ammonium nitrate in the form of prills and connected to an inlet end (2) of a screw feeder (3),

- a means for injecting an inverse emulsion (4) comprising nitrate, arranged close to an outlet end (5) of the screw feeder (3).

- a vertical tubular element (6) of which an inlet end (7) is connected to the outlet end (5) of the screw feeder (3) and an outlet end (8) is connected to an outlet end inlet (9) of a screw mixer (10) and

- a second hopper (11) intended to contain small-sized hollow bodies connected to the vertical tubular element (6) via a means (12) for injecting small-sized hollow bodies disposed close to the outlet end (8) of said vertical element (S).

The installation according to the invention advantageously has a measured size, is not very complex, easy to install, to disassemble and to transport so as to be able to prepare in a secure manner an explosive composition in the form of cartridges near the site of implementation of said composition. In addition, the installation according to the present invention advantageously makes it possible to prepare an explosive composition which is stable over time and which can be packaged for later implementation in the form of cartridges.

In particular, the installation according to the present invention makes it possible to prepare an explosive composition cold and more precisely at a temperature between 20 and 50 degrees Celsius, preferably between 25 and 45 degrees Celsius. The possibility of preparing the explosive composition cold advantageously makes it possible to have a compact installation, easy to install, easy to transport, and whose implementation is secure.

The installation according to the present invention can be considered as a "modular installation" for the preparation of an explosive composition, that is to say that it is an installation comprising several elements which can be detached and then reattached to each other so as to have an installation that can be easily disassembled, assembled and transported. The installation according to the invention can be supplemented by additional elements.

The term "explosive composition" means a composition in which the essential pyrotechnic characteristics such as the critical diameter or the sensitivity to the primer are sufficient, so that this composition is sensitive to an initiating chain consisting of a detonator and/or or a booster. For example, a composition in a packaging with a diameter of approximately 70mm having a detonation velocity in the open air of between 4000 and 5000 m/s is considered to be an explosive composition presenting the essential pyrotechnic characteristics.

The term "hopper" means a container preferably in the form of a funnel intended to store elements and to distribute, release by gravity a quantity of the stored elements. Preferably in the context of the present invention, the hoppers implemented are metering hoppers, distributing, releasing a determined dose or quantity of the stored elements.

The term “in the form of prilis” refers to agglomerates of small-sized material in this case of oxidizing salts such as ammonium nitrate, said agglomerates possibly being in the form of a dry pellet made from a liquid. Preferably, the small agglomerates, or prilis, of oxidizing salts used in the present invention have a size of between 0.5 and 2 mm.

The "inverse emulsion" according to the invention corresponds to a "water in oil" emulsion obtained by mixing an oily continuous phase, consisting of a mixture of various fuels such as a vegetable and/or mineral fatty substance such as oils: mineral or organic oils, and at least one surfactant and one phase. aqueous discontinuous consisting of various oxidizing salts in aqueous solution.

In the context of the present invention, the oxidizing raw materials that can be used can be different salts chosen from: ammonium nitrate, sodium nitrate, calcium nitrate, or a mixture of these salts, preferably sodium nitrate. 'ammonium. The fuels that can be used can be chosen from: diesel fuel pure or mixed with new or used mineral oils, such as recycled motor oil, paraffin oils.

Preferably, the inverse emulsion according to the invention comprises an oily continuous phase, consisting of new or used mineral oils, and at least one surfactant and a discontinuous aqueous phase dispersed in the oily phase, consisting of nitrate salts in solution. aqueous, preferably ammonium nitrate.

For example, the aqueous phase can be prepared by dissolving at least one nitrate salt in water, preferably several nitrate salts, in which additives can be added which promote the dispersion of small hollow bodies and additives for adjusting the pH of the aqueous phase. Due to the high concentration of nitrate salts in the aqueous phase, and in order to facilitate their dissolution, the water is heated to a temperature of at least 65° Celsius. In order to promote mixing and to reduce the temperature difference between the aqueous phase and the oily phase, the oily phase can be heated to a temperature of between 40° and 90° C., preferably 50-70° C. The mixing of the two phases as such can thus be carried out without heating.

By "small-sized hollow body" is meant in the context of the present invention, small-sized hollow bodies capable of generating a dispersion within the matrix, that is to say within the inverse emulsion in which ammonium nitrate was added, the size of which is between a few tens and a few hundred microns. The small-sized hollow bodies according to the invention can be chosen from glass microbeads, thermoplastic polymer cilles, expanded polystyrene beads or a mixture of the latter. Preferably your size of small hollow bodies, is between 100 and 200 micro reefs, .preference. between 100 and 150 microns. More preferably, the hollow bodies of small size in the context of the present invention are glass microbeads, preferably having a size between 100 and 150 microns and a density of 0.15 +/- 0.02.

The term "screw mixer" refers to a device ensuring progressive mixing and homogenization of a mixture with gentle shearing. The screw mixer can for example be a conical, ribbon or single-shaft screw mixer such as a single-shaft Archimedes screw mixer. Preferably within the scope of the invention, the screw mixer is a single-shaft Archimedes screw mixer. The screw mixer according to the invention makes it possible to ensure continuous mixing.

In the context of the present invention, the term "screw feeder" refers to a weight or volumetric dosing device, ensuring a uniform, progressive and controlled flow and release of an element contained in a hopper. For example in the present invention, the screw feeder allows a uniform, progressive and controlled flow and release of ammonium nitrate in the form of prills from the first hopper.

In particular in the context of the present invention, the screw feeder to which the first hopper is connected, is a screw feeder comprising nitrate, in particular had ammonium nitrate. The screw feeder according to the present invention can be connected to a pump making it possible to convey the ammonium nitrate therein.

The screw feeder comprising nitrate within the scope of the present invention has an inlet end and an outlet end, between which there is a multitude of turns, separated from each other by an identical distance. .

The means for injecting the inverse emulsion near the outlet end of the screw feeder can for example be a metering pump or even a screw feeder as defined upstream, optionally connected to a pump, preferably the means of injection of the emulsion is a metering pump.

The means for injecting the inverse emulsion according to the invention is placed at a distance of between 0 and 5, preferably between 0 and 3, number of turns with respect to the outlet end of the screw feeder.

In particular according to the present invention, the reverse emulsion injection means (4) is arranged at a distance of between 0 and 1 number of turns relative to the outlet end (5) of the screw feeder (3) .

In other words, the emulsion injection means is placed at a distance of between 80 and 100%, preferably between 85 and 95% of the total length of the screw feeder with respect to the outlet end of the screw feeder.

The arrangement of the emulsion injection means relative to the outlet end of the screw feeder advantageously makes it possible to inject the inverse emulsion within the screw feeder comprising the ammonium nitrate shortly before it is released into the vertical tubular element, so that the premix formed, also called matrix in the context of the present invention, corresponding to the inverse emulsion supplemented with ammonium nitrate in the form of priils, is non-homogeneous when released within the vertical tubular element.

The vertical tubular element implemented in the installation according to the invention comprises an inlet end and an outlet end. The inlet end of the vertical tubular element is coupled directly or indirectly to the outlet end of the screw feeder and the outlet end of the vertical tubular element is coupled directly or indirectly to the outlet end of the screw mixer.

The vertical tubular element is intended to be crossed by the matrix corresponding to the inverse emulsion supplemented with ammonium nitrate in the form of priMs.

The means for injecting small-sized hollow bodies, preferably glass microbeads, can for example be a metering pump or even a screw metering device as defined upstream, optionally connected to a pump, preferably the means of injection of small hollow bodies is a screw feeder called screw feeder for small hollow bodies. The means for injecting small-sized hollow bodies is connected directly or indirectly with the vertical tubular element, in particular near the outlet end of said element, and is connected directly or indirectly to a second hopper containing the hollow bodies short.

According to the invention, the injection means (12) for small-sized hollow bodies is arranged above the outlet end (6) of the vertical tubular element (6), at a height of between 40 and 60% the total length of the tubular element (5).

The arrangement of the means for injecting small-sized hollow bodies advantageously makes it possible to inject the small-sized hollow bodies into the vertical tubular element at the end of the fall of the inhomogeneous premix, or even matrix, so that the bodies small hollows injected form a cloud of small hollow bodies within the vertical tubular element and are more easily dispersed within the matrix.

In the installation according to the present invention, the outlet end of the vertical tubular element is connected directly or indirectly to an inlet end of a screw mixer. The screw mixer comprises an inlet end and an outlet end between which there is a multitude of screw threads or turns.

According to a first particular embodiment, the screw mixer used in the installation according to the present invention is of sufficient length for the non-homogeneous mixture formed by the matrix, namely the inverse emulsion supplemented by the nitrate ammonium, and small bodies, is mixed for sufficient time to form a homogeneous mixture at the outlet end of the auger mixer.

According to a particular aspect of the installation according to the invention, the distance between an inlet end (9) and an outlet end (14) of the screw mixer (10) is between 100 and 500 cm.

In the context of the present invention, a mixture is considered to be "inhomogeneous", when all or part of its constituents are visible to the naked eye, and "homogeneous" when all or part of its constituents are not visible to the naked eye. the naked eye.

In particular, the installation according to the present invention comprises a third hopper (13) capable of recovering the explosive composition, connected to an outlet end (14) of the screw mixer (10).

The third hopper can be connected directly or indirectly to an outlet end of the screw mixer. The third hopper is connected directly or indirectly to a do wear pump, itself connected directly or indirectly to the clipper.

More particularly, in the installation according to the present invention the third hopper (13) is connected to a metering pump (15) itself connected to a clipper (16).

The term "clipper" means a manual or automatic machine, preferably automatic, intended to close the container, the packaging in which the explosive composition is packaged.

A second object of the invention relates to a process for preparing an explosive composition in which successively,

- a dose of ammonium nitrate in the form of prills is premixed with a dose of inverse emulsion comprising nitrate to form a premix,

- the pre-mix passes through a vertical tubular element (6) towards an outlet end (7) of said element,

- a dose of small hollow bodies is injected into the vertical tubular element (6) close to the outlet end (8) of said element and before the premix reaches the outlet end (8) of the vertical tubular element (6), so as to form an inhomogeneous mixture,

- the inhomogeneous mixture formed at the outlet end (8) of the tubular element (6) is released into a screw mixer (ICi, so as to form a homogeneous mixture corresponding to the explosive composition.

The process according to the invention uses the following components in percentage by weight relative to the total weight of components used: between 10 and 40% of ammonium nitrate, between 65 and 80% of inverse emulsion and between 1 and 6% small hollow bodies, preferably glass microbeads.

In particular, the method according to the present invention has a rate of preparation of an explosive composition of between 25 and 60 kg/min.

In the method according to the present invention, the flow rate of each component can be adjusted manually by electronic means via a touch screen.

The method according to the present invention is capable of being implemented using an installation according to the first object of the invention.

All of the definitions ci specific characteristics and pretéœescenncées upstream for the first object of the invention namely the instaiaLisn, sè ^ opl'qqent mutatis mutandis to the second object of the invention namely the process for preparing a composition explosive.

In particular, the present invention relates to a process for preparing an explosive composition in which successively,

- the dose of ammonium nitrate in the form of prills is released from a first hopper (1) within an inlet end (2) of a screw feeder (3)

- the inverse emulsion is added within the screw feeder (3) by an injection means (4) placed close to an outlet end (5) of the screw feeder, so as to form a premix

- the premix formed is released within the vertical tubular element (6) via the outlet end (5) of the screw feeder (3) connected to an inlet end (7) of said vertical tubular element

- the dose of small hollow bodies is released from a second hopper (11) to be injected into the vertical tubular element (6) by an injection means (12), so as to form a mixture not homogeneous

- the inhomogeneous mixture formed is released from the outlet end (8) of the vertical tubular element (6) into an inlet end (9) of a screw mixer (10)

- after passing the inhomogeneous mixture through the screw mixer (10), the homogeneous mixture formed corresponding to an explosive composition is recovered in a third hopper (13), connected to an outlet end (14) of the screw mixer ( 10).

The premix, or matrix according to the invention, corresponds to the inverse emulsion supplemented with ammonium nitrate in the form of hairs. The non-homogeneous mixture formed corresponds to the premix supplemented by the dose of small hollow bodies, preferably glass microbeads.

According to the invention, the homogeneous mixture, that is to say the explosive composition obtained at the end of the process, comprises in percentage by weight relative to the total weight of the mixture; between 10 and 40% anvicrium nitrate, between 65 and 80% invert emulsion and between 1 and 6% hollow bodies with a slope ta:ae, preferably glass microbeads.

In particular, in the preparation process according to the invention, the inverse emulsion comprises:

an aqueous phase comprising at least one dissolved nitrate salt and an oily phase comprising at least one vegetable and/or mineral fatty substance and a surfactant.

The vegetable and/or mineral fatty substance can be chosen from mineral oils or organic oils, and the nitrate salt can be chosen from ammonium nitrate, sodium nitrate, calcium nitrate, or a mixture of these be, preferably ammonium nitrate.

The process according to the invention advantageously makes it possible to prepare an explosive composition with a cold inverse emulsion, more precisely at a temperature between 20 and 50°C. In particular, this allows cfe to have a process that is easier to implement and less expensive.

In particular, in the preparation process according to the invention, all of the steps are carried out at a temperature of between 25 and 45°C.

More particularly in the process according to the invention, the pre-mixing of the ammonium nitrate in the form of grills and of the emulsion is carried out for 2 to 10 seconds.

More particularly in the method according to the invention, the inhomogeneous mixture is mixed in the screw mixer (10) for 1 to 3 minutes.

The process according to the present invention advantageously makes it possible to prepare explosive compositions in the form of cartridges, with a diameter of between 50 and mm, said compositions in cartridge form being easy to transport and to store.

A third object of the present invention relates to an explosive composition comprising ammonium nitrate in the form of prilis, an inverse emulsion 5 comprising nitrate, and small hollow ^bodies , packaged in the form of cartridges of 50 to 90 mm. in diameter characterized in that it has a detonation velocity of between 4000 and 5000 m/s in the open air.

Preferably, the explosive composition according to your present invention is packaged in the form of a cartridge 70 mm in diameter has a detonation speed of between 4000 and 5000 m/s in the open air.

The explosive composition according to the present invention comprises, in percentage by weight relative to the total weight of the mixture: between 10 and 40% of ammonium nitrate, between 65 and 80% of inverse emulsion and between 1 and 6% of hollow bodies small in size, preferably glass microbeads.

Another object of the present invention relates to an explosive composition obtained by implementing a method according to the second object of the invention.

Claims (11)

[Claim 1] Installation for the preparation of an explosive composition comprising: - a first hopper (1) intended to contain ammonium nitrate in the form of prills and connected to an inlet end (2) of a screw feeder (3), - a means of injecting an inverse emulsion (4) comprising nitrate, arranged close to an outlet end (5) of the screw feeder (3), - a vertical tubular element (6) of which an inlet end (7) is connected to the outlet end (5) of the screw feeder (3) and an outlet end (8) is connected to an end of inlet (9) of a screw mixer (10) and - a second hopper (11) intended to contain small-sized hollow bodies connected to the vertical tubular element (6) via a means (12) for injecting small-sized hollow bodies disposed close to the outlet end (8) of said vertical element (6). [Claim 2] Installation according to claim 1 in which the means for injecting the inverse emulsion (4) is arranged at a distance of between 0 and 1 number of turns relative to the outlet end (5) of the dispenser screws (3). [Claim 3] Installation according to one of Claims 1 or 2, in which the means (12) for injecting small hollow bodies is arranged above the outlet end (8) of the vertical tubular element (6), at a height of between 40 and 60% of the total length of the tubular element (6). [Claim 4] Installation according to any one of the preceding claims, in which the distance between an inlet end (9) and an outlet end (14) of the screw mixer (10) is between 100 and 500 cm. [Claim 5] Installation according to any one of the preceding claims comprising a third hopper (13) capable of recovering the explosive composition, connected to an outlet end (14) of the screw mixer (10). [Claim 61 installation according to claim 5 wherein the third hopper (13) is connected to a metering pump (15) itself connected to a clipper (16). [Claim 7] Process for the preparation of an explosive composition in which successively, - a dose of ammonium nitrate in the form of prills is pre-mixed with a dose of inverse emulsion comprising nitrate to form a pre-mixture, - the pre-mix passes through a vertical tubular element (6) in the direction of an output end (7) of said element, - a dose of small-sized hollow bodies is injected into the vertical tubular element (6) near the outlet end (8) of said element and before the premix reaches the outlet end (8 ) of (vertical tubular element (6), so as to form an inhomogeneous mixture, - the inhomogeneous mixture formed at the outlet end (8) of the (tubular element (6) is released into a screw mixer (10), so as to form a homogeneous mixture corresponding to the explosive composition. [Claim 8] Preparation process according to claim 7 wherein successively, - the dose of ammonium nitrate in the form of prills is released from a first hopper (1) within an inlet end (2) of a screw feeder (3) - (inverse emulsion is added within the screw feeder (3) by an injection means (4) placed near an outlet end (5) of the screw feeder, so as to form a premix - the premix formed is released within (vertical tubular element (6) via (outlet end (5) of the screw feeder (3) connected to an inlet end (7) of said vertical tubular element - the dose of small hollow body is released from a second hopper (11) to be injected into the vertical tubular element (6) because an injection means (12), so as to form a mixture not homogeneous - the inhomogeneous mixture formed is released from (outlet end (8) of (vertical tubular element (3) into an inlet end (9) of a screw mixer (10) - after passing the inhomogeneous mixture through the screw mixer (10), the homogeneous mixture formed corresponding to an explosive composition is recovered in a third hopper (13), connected to an outlet end (14) of the screw mixer ( 10). 5 [Claim 9] A method according to any of claims 7 to 8 wherein the invert emulsion comprises: an aqueous phase in which the nitrate is dissolved and an oily phase comprising at least one vegetable fat! and/or mineral and a surfactant. [Claim 10] Process according to any one of claims / to 9 io in which all the steps are carried out at a temperature of between 25 and 45°C. [Claim 11] Process according to any one of Claims 7 to 10, in which the pre-mixing of the ammonium nitrate in the form of prills and the emulsion is carried out for 2 to 10 seconds. is [Claim 12] A method according to any one of claims 7 to 11 wherein the inhomogeneous mixture is mixed in the screw mixer (10) for 1 to 3 minutes.