Process for manufacturing metal powder and device for implementing the process.

Abstract

The invention relates to a method for manufacturing a metal powder from a gas comprising a metal halide, as well as a device for manufacturing a metal powder and a system comprising such a device. Figure for the abstract: 3

Description

Title of the invention: Process for manufacturing metal powder and device for implementing the process. Technical field of the invention

[0001] The present invention relates to a method for manufacturing a metal powder from a gas comprising a metal halide, as well as a device for manufacturing a metal powder and a system comprising such a device. Prior art

[0002] Transition metals, for example molybdenum, rhenium, tungsten or iridium, can be used in many technical fields, for example in the medical field or in telecommunications.

[0003] It is therefore advantageous to have these metals in powder form.

[0004] The powder can then be used as a raw material to manufacture more complex metal products.

[0005] For certain applications, for example in the medical or pharmaceutical field, the metal powder must have a relatively high degree of purity, as well as a controlled isotopy.

[0006] Document CN113020617A discloses, for example, a process for preparing an ultrafine refractory metal powder with a high level of purity. The process described in this document includes a step of heating and evaporating a metal halide in an evaporator, supplying the metal halide and hydrogen vapor to a reactor to obtain an ultrafine metal powder, a step of separating the superfine metal powder from the residual gas and heat-treating the powder, and a step of passivating the metal powder. However, such a process requires a preheating step for the metal halide and hydrogen vapor upstream of the reactor. Furthermore, the mixing of these gaseous phases takes place directly in the reactor, which is likely to limit the process yield and generate a powder with a less homogeneous particle size due to insufficient homogeneity of the gas mixture.This process is also geared more towards the production of nanoparticles than micrometer-sized particles. CN113020617 uses a filter for particle recovery, which has the drawback that the flow rate can vary as the filter fills.

[0007] Document EP1579936 discloses a process for producing a metal powder, comprising a step of gas-phase reduction of a metal chloride in the presence of a reducing gas, and a step of cooling The metal powder is generated using a blown inert gas that creates a vortex flow. This cooling in a vortex flow limits particle aggregation and adhesion to the internal walls of the metal powder production device. However, this process requires a complex system capable of implementing a cooling gas flow in parallel with the flows of gaseous metal chlorides and reducing gas, as well as a fluidic system configured to create a vortex.

[0008] Thus, there is a need to propose a process for manufacturing metal powder that is both simple and quick to implement, and that allows the production of metal powder with a high yield, a controlled particle size, and conservation of the isotopy of the metal atoms.

[0009] The present invention thus aims to remedy at least in part the aforementioned disadvantages, and to provide other advantages. Description of the invention

[0010] To this end, a process for manufacturing a Me metal powder is proposed according to a first aspect, comprising at least the following steps:

[0011] - A step of supplying a first gas comprising a metal halide;

[0012] - A step of supplying a second gas comprising dihydrogen;

[0013] - A step of mixing the first gas and the second gas producing a mixture gaseous;

[0014] - A heating step of a reaction chamber to a temperature, called reaction temperature, between 950°C and 3000°C, for example between 950°C and 2500°C, and;

[0015] - A step of pressurizing the reaction vessel to a pressure, called reaction pressure, between 200 mbar and 500 mbar;

[0016] - A step of injecting the gas mixture into the reaction vessel maintained at the reaction temperature and reaction pressure;

[0017] - A reaction step of the halide and dihydrogen from the gaseous mixture, in the reaction chamber maintained at the reaction pressure, and at the reaction temperature, producing the metallic powder of metal Me.

[0018] In the context of this description, powder conventionally refers to a collection of particles, also referred to as "grains", each particle being formed from an agglomerate of crystallites.

[0019] Such a process makes it possible to prepare a metal powder with a controlled particle size and high chemical purity. Furthermore, such a process does not affect the isotopy of the metal atoms. Thus, the isotope of the metal atom in the metal halide (gaseous precursor) will be retained in the resulting metal powder.

[0020] Such a process is also simple and quick to implement, in particular in that it makes it possible to dispense with a step of preheating the gases before introduction into the enclosure where the reaction takes place, the heating of the gases in the reaction enclosure being sufficient to allow the manufacture of the powder.

[0021] Finally, the mixing of the first gas and the second gas before introduction into the enclosure prevents the occurrence of turbulence which could be caused by the introduction of two gas flows at different flow rates into the enclosure of the device in which the reaction takes place, which would be likely to disrupt the reaction.

[0022] In one example of implementation, the process according to the invention includes a step of evacuating the enclosure, for example to a pressure below 105 mbar, prior to the step of pressurizing the reaction enclosure to a reaction pressure.

[0023] In one example of implementation, the process includes a step of gravity deposition of the metal powder into a collector disposed downstream of the reaction chamber.

[0024] According to a preferred embodiment example, the gravity deposition step includes a step of pressurizing the recuperator, to a pressure, called the recovery pressure, the recovery pressure being lower than the reaction pressure.

[0025] Such a gravity deposition step allows the recovery of the manufactured metal powder in a simple way, without resorting to the use of a filter which would require higher maintenance.

[0026] In one example of an implementation, the metal halide of the first gas has the formula MeyXz in which Me is a transition metal, for example molybdenum, rhenium, tungsten or iridium; X is a halogen, for example fluorine, chlorine, bromine or iodine; y and z are each an integer greater than or equal to 1.

[0027] For example, the metal halide of the first gas is molybdenum hexafluoride (MoF6).

[0028] In a preferred embodiment example, the first gas comprises at least 99.9999 wt. % of the metal halide (“%wt.” or “wt.%” denoting a mass percentage).

[0029] The process makes it possible to produce a metal powder having a level of purity of the same order of magnitude as the level of purity of the metal halide (gaseous precursor). Thus, if the process uses a first gas having a high level of purity, for example a purity level of 6N (i.e., pure to at least 99.999%), a metallic powder with a corresponding level of purity will be obtained.

[0030] When reference is made to a purity level of 6N for a chemical species in reference to a powder or gas in this description, it is understood that the gas or powder comprises at least 99.9999 wt. % of the chemical species.

[0031] In one example of implementation, the process includes a step of stopping the injection of the gas mixture.

[0032] Stopping the gaseous mixture causes the reactants to be exhausted and the reaction to stop.

[0033] In one example of implementation, the process includes a step of cooling the enclosure, from the reaction temperature to an ambient temperature.

[0034] For example, the ambient temperature is lower than the reaction temperature. For example, the ambient temperature is between -30°C and +50°C.

[0035] For example, the chamber cooling step takes place after the gravity deposition step.

[0036] For example, such a cooling step of the enclosure takes place after the step of stopping the injection of the gas mixture.

[0037] In one example of implementation, the process includes a step of returning the enclosure to ambient pressure from the reaction pressure.

[0038] For example, the step of restoring ambient pressure to the enclosure takes place after the gravity deposition step.

[0039] For example, such a step of restoring the enclosure to ambient pressure takes place after the step of stopping the injection of the gas mixture.

[0040] In one embodiment example, a gas, for example nitrogen or hydrogen, for example a passivation gas, can be introduced into the enclosure during the cooling stage of the enclosure and during the stage of restoring the enclosure to ambient pressure.

[0041] Such cooling and re-pressurizing steps of the enclosure facilitate powder recovery.

[0042] In one example of implementation, the process includes a step of passivating the metal powder.

[0043] This step is, for example, a prerequisite to a powder recovery step.

[0044] For example, the step of passivating the metal powder includes bringing said metal powder into contact with a passivating gas.

[0045] For example, the passivation gas may comprise oxygen, in a content between 0.00001% wt. and 0.005% wt.

[0046] For example, the passivation gas may include water vapor in a content between 0.00001 wt. % and 0.005 wt. % ("wt.%" or "%wt." here denotes a mass percentage).

[0047] Such a passivation step makes it possible to generate an oxide film on the surface of the metal powder particles.

[0048] Such an oxide film makes it possible to limit subsequent oxidation phenomena of the powder and thus promote its preservation and transformation where appropriate.

[0049] In one example of implementation, the method comprises: - a step of recovering a residual gas at the end of the reaction step; and - a step of washing the recovered residual gas, the washing step comprising a substep of mixing the recovered residual gas with a washing solution having a pH between 7 and 14, and a substep of neutralizing at least one chemical species present in said recovered residual gas.

[0050] Such recovery and washing of the residual gas makes it possible to limit, or even eliminate, the release of toxic elements into the environment.

[0051] In one embodiment, the first gas comprising the metal halide is injected at a first flow rate of between 50 sccm and 150 sccm. (sccm stands for "standard cubic centimeters per minute", which corresponds to the mass flow rate of a gas (cm3 / min) under standard temperature and pressure conditions, namely a standard temperature of 0°C and a standard pressure of 1 atm).

[0052] Such a flow rate of the first gas contributes to the control of the size of the particles generated, while giving the process a satisfactory yield, for example greater than or equal to 85%, and limiting the losses in metal halides.

[0053] In one embodiment example, the gas mixture obtained in the first gas and second gas mixing step comprises a volume ratio of dihydrogen to metal halide of between 3 and 30, for example between 5 and 10.

[0054] Such a volume ratio of dihydrogen to metal halide contributes to controlling the size of the generated particles, while giving the process a satisfactory yield, for example greater than or equal to 85%, and limiting losses in metal halides.

[0055] The invention also proposes, according to a second aspect, a metallic powder comprising a metallic species Me, with a content between 99.9999 wt.% and 100 wt.% (mass percentage relative to the total mass of the powder).

[0056] Such a metal powder thus exhibits a high purity, i.e., for example, of at least "6N". Such a powder is then, for example, compatible with pharmaceutical and / or medical applications.

[0057] The metal powder can be made up of particles, preferably spherical particles.

[0058] In one embodiment example, at least 95% of the metal powder particles have an average diameter between 0.4 pm and 5 pm.

[0059] The invention also proposes, according to a third aspect, a device for manufacturing a metallic powder.

[0060] The device includes, for example: - an enclosure, comprising an inlet configured to inject a gaseous mixture into the enclosure, and at least one outlet configured to vent residual gas and metallic powder from the enclosure, - a recovery unit comprising: - a fluidic communication input with at least one output of the enclosure, - at least one outlet configured to extract residual gas from the recuperator, and - a base configured to collect the obtained powder.

[0061] The recuperator may include at least one baffle, configured to slow down the residual gas and metal powder from the enclosure, allowing the metal powder to settle at the bottom of the recuperator.

[0062] Such a recuperator in a manufacturing device according to an embodiment of the invention makes it possible to recover the metal powder by gravity by reducing the speed of the gas flow.

[0063] For example, the collector has a side wall extending from the bottom of the collector and surrounding the bottom of the collector.

[0064] For example, the side wall of the recuperator surrounds the baffle of the recuperator.

[0065] For example, the side wall of the collector includes holes constituting the minus one outlet from the recuperator.

[0066] For example, the reclaimer has in its center a pin extending from the bottom of the reclaimer towards the exit of the enclosure.

[0067] For example, the pawl of the recuperator is configured to direct the residual gas flow and powder between the baffle of the recuperator and the bottom of the recuperator.

[0068] The baffle of the recuperator is configured to divert the residual gas flow for extraction from the device.

[0069] The baffle thus helps to slow down the residual gas flow, promoting the deposition of the powder at the bottom of the recuperator.

[0070] For example, the baffle includes at least one tubular element surrounding the outlet of the enclosure.

[0071] Thus, in operation, the residual gas flow and the powder flow inside the tubular element.

[0072] For example, the tubular element can be fixed to a tray delimiting a bottom of the enclosure.

[0073] For example, the tubular element is disposed at a distance from the bottom of the collector.

[0074] Thus, in operation, the residual gas flow, after passing inside the tubular element, flows between the tubular element and the bottom of the collector.

[0075] In one embodiment, at least one tubular element is a first tubular element, and the baffle comprises a second tubular element, surrounding the first tubular element.

[0076] For example, the second tubular element can be fixed to the bottom of the collector.

[0077] Thus, in operation, the residual gas flow, after passing between the first The tubular element and the bottom of the collector, flows between the second element and the tray.

[0078] For example, the reclaimer includes a pin which extends from the bottom of the reclaimer towards the outlet of the enclosure, the pin being centered on the axis of the outlet of the enclosure.

[0079] For example, the pin has a conical head, configured to direct the residual gas flow between the first tubular element and the bottom of the recuperator.

[0080] In the operating device, the recuperator is located below the reaction chamber, so that gravity allows the recovery of the metal powder while the speed of the gaseous flow carrying the powder decreases.

[0081] Thus, leakage of prepared powders by entrainment in the gas stream is limited out of the device, thereby optimizing the yield of a process implemented in such a device.

[0082] Without going out of the scope of the invention, other geometries of the recuperator are possible, for example with horizontal plates forming the baffles.

[0083] Furthermore, such a device is simplified, in that it only includes a single means for injecting gases into the enclosure.

[0084] In one embodiment, the enclosure of the device for manufacturing a metal powder is made at least in part of a Me metal, or even at least 99 wt. % of Me metal, the Me metal being identical to the Me metal of the metal powder manufactured by the process described above.

[0085] In one embodiment, the collector of the device for manufacturing a metal powder is made at least partly of a Me metal, or even of at least 99 wt.% of Me metal, the Me metal being identical to the Me metal of the metal powder manufactured by the process described above.

[0086] For example, when the powder manufacturing device is implemented to manufacture molybdenum powder, the enclosure and the collector of the device are then made of molybdenum.

[0087] An enclosure and a collector of the same chemical nature as the metal powder to be manufactured makes it possible to maintain a level of purity of the powder to be produced and to limit a risk of contamination, for example by another chemical species during the manufacture of the powder.

[0088] Such a device makes it possible to control the flow of gas and particles in the enclosure and in the recuperator.

[0089] For example, an upper part of the enclosure, near the inlet, allows for the expansion of the gases and the stabilization of the flow. A second part of the enclosure, below the upper part, is an area where the reaction between the metal halide and dihydrogen takes place.

[0090] Finally, according to a fourth aspect, the invention proposes a system for manufacturing a metallic powder comprising:

[0091] - a device for manufacturing a metal powder as described above; - a chamber configured to be hermetically sealed, with the manufacturing device located inside the chamber,

[0092] - a heating means, disposed in the chamber, and configured to heat said manufacturing device

[0093] - a pump, configured to modulate a pressure in at least the enclosure of the device; and - a gas circuit comprising: • at least one primary gas supply line, • a second supply line for a second gas, • a mixer configured to mix the first gas and the second gas and provide a gaseous mixture, the mixer comprising: • an initial fluidic communication entry with the first power supply line, • a second fluidic communication input with the second power supply line, • an output in fluidic communication with an input of the enclosure of the device for manufacturing a metal powder and configured to inject the gaseous mixture into the enclosure of the device.

[0094] Such a system makes it possible to control the pressure and temperature parameters inside the enclosure of the device.

[0095] For example, at least one output of the device is in fluidic communication with the chamber.

[0096] This makes it possible to control the yield of the process implemented in the system and to finely control the parameters of the powders obtained.

[0097] Such a system allows two gases from two different lines upstream of the chamber of the system comprising the device in which the reaction takes place to be mixed, thus simplifying the assembly of such a system and limiting possible turbulence which could be caused by the introduction of two gas flows at different flow rates into the device in which the reaction takes place, which would be likely to disrupt the reaction.

[0098] In one embodiment, the heating means of the system is an induction coil, the induction coil being disposed within said chamber and around the manufacturing device.

[0099] In one embodiment, the pump is configured to recover residual gas at the outlet of the device enclosure.

[0100] The residual gas can exit the metal powder manufacturing device through an outlet 17 of the recuperator, thus passing into the chamber. The residual gas then passes through an outlet of the chamber and is recovered by the pump.

[0101] In one embodiment, the system includes a gas scrubber.

[0102] Such a gas scrubber makes it possible to limit, or even eliminate, the release of toxic elements into the environment.

[0103] For example, the gas scrubber is in fluidic communication with the pump.

[0104] For example, the gas scrubber is arranged downstream of the chamber.

[0105] For example, the gas scrubber is configured to neutralize at least one species chemical present in the residual gas.

[0106] For example, the gas scrubber is configured to produce a basic species shower enabling the neutralization of at least one chemical species present in the residual gas. Brief description of the figures

[0107] The invention, according to an exemplary embodiment, will be better understood and its advantages will become more apparent upon reading the following detailed description, given by way of example and not limitation, with reference to the accompanying drawings in which:

[0108] Fig. 1 represents a device for manufacturing a metal powder according to an example of an embodiment of the invention, semi-assembled;

[0109] Figure [Fig. 2] represents a device for manufacturing a metal powder according to a example of an embodiment of the invention, in cross-section;

[0110] Fig. 3 schematically represents a system configured to implement the process according to an example of implementation of the invention;

[0111] Figure 4 illustrates a statistical distribution of the particle size of a powder produced by the process according to an example of an embodiment of the invention; and

[0112] Figure 5 illustrates the shape of a sample of particles of a powder produced by the process according to an example of implementation of the invention. Detailed description

[0113] Method according to an example of implementation of the invention:

[0114] According to the invention, a metal powder is prepared from a metal halide.

[0115] A metal powder herein means a powder whose particles are made up at least in part of a metal Me. As described below, the powder obtained according to an example of an embodiment of the invention is made up of at least 99.9999 wt.% of the metal Me.

[0116] To do this, the chosen metal halide then comprises the same metal Me.

[0117] Gas supply and mixing steps.

[0118] The process includes a step of supplying a first gas comprising a metal halide comprising the metal Me.

[0119] Such a metal halide in the first gas may be of formula MeyXz, in which Me may be a transition metal, for example molybdenum, rhenium, tungsten or iridium; X may be a halogen, for example fluorine, chlorine, bromine or iodine; y and z are each an integer equal to or greater than 1.

[0120] The first gas may comprise a metal halide at a high level of purity. By way of example, the first gas comprises a metal halide with a content between 99.9999 wt.% and 100 wt.%, which also corresponds to a degree of chemical purity of 6N.

[0121] By way of example, the metal halide in the first gas may be molybdenum hexafluoride MoF6.

[0122] In one example of implementation, the first gas comprising the metal halide is supplied at a first flow rate, the first flow rate being between 50 sccm and 150 sccm.

[0123] The process includes a step of supplying a second gas comprising dihydrogen.

[0124] In one example of implementation, the second gas comprising at least 99.9999% dihydrogen, that is to say that the second gas comprises nearly 100% dihydrogen, without taking into account any impurities present in negligible amounts.

[0125] In one embodiment, the second gas is supplied at a second flow rate.

[0126] For example, the second flow rate may be between 150 sccm and 4500 sccm.

[0127] The second flow rate can be chosen according to the first flow rate set for the first gas.

[0128] In one example of implementation, the ratio between the flow rate of the second gas and the flow rate of the first gas is between 3 and 30.

[0129] The process also includes a step of mixing the first gas comprising metal halide and the second gas comprising dihydrogen, thus producing a gaseous mixture comprising metal halide and dihydrogen.

[0130] Heating and pressurization steps of a reaction vessel

[0131] The process includes a step of heating a reaction chamber.

[0132] In one example of implementation, the reaction chamber can be heated to a reaction temperature between 950°C and 3000°C, for example between 950°C and 2500°C.

[0133] According to one example of implementation, the reaction temperature can be between 950°C and 2000°C, or even for example between 950°C and 1500°C.

[0134] The process also includes a step of pressurizing the reaction vessel.

[0135] In one embodiment, such a pressurization step can be carried out using a pumping system. In one embodiment, the reaction vessel can be brought to a reaction pressure of between 200 mbar and 500 mbar.

[0136] In one example of implementation, the heating and pressurization steps of the reaction vessel can take place consecutively.

[0137] In one example of implementation, the process according to the invention includes, prior to the step of pressurizing the enclosure to the reaction pressure, a step of evacuating the enclosure, for example to a pressure below 105 mbar.

[0138] Injection and reaction steps

[0139] The process includes a step of injecting the gas mixture into the reaction chamber.

[0140] During the injection step, the reaction chamber is maintained at the reaction temperature and reaction pressure.

[0141] The process includes a step of reacting the halide and dihydrogen from the gas mixture, producing the metal powder.

[0142] Such a step can take place in the reaction chamber, which is maintained at the reaction temperature and reaction pressure.

[0143] Such temperature and pressure conditions allow the reaction to take place and thus the desired metal powder to be produced.

[0144] In one example of implementation, maintaining the reaction temperature and reaction pressure in the reaction chamber during the injection of the gas mixture into the reaction chamber allows the reaction to take place.

[0145] In an alternative embodiment example, the heating and pressurization steps of the reaction vessel can take place simultaneously.

[0146] Gravity deposition steps

[0147] In one embodiment example, the process includes a step of gravity deposition of the obtained metal powder, for example into a collector arranged under the reaction chamber.

[0148] Such a gravity deposition step can take place concomitantly with the reaction step.

[0149] Such a gravity deposition step may include a substep of pressurizing the recuperator to a so-called "recovery" pressure.

[0150] The recovery pressure is then lower than the reaction pressure.

[0151] Such a pressure difference between the reaction pressure in the enclosure and the recovery pressure in the recuperator makes it possible to extract a residual gas and a metallic powder out of the enclosure, and into the recuperator.

[0152] Cooling and ambient pressure stage

[0153] According to one embodiment, the process may include a step of cooling the enclosure from the reaction temperature to an ambient temperature.

[0154] According to one embodiment, the process may include a step of returning to ambient pressure, from the reaction pressure to ambient pressure.

[0155] During such a step of returning to ambient pressure, the atmosphere in the enclosure may include dinitrogen, preferably the atmosphere in the enclosure consists of dinitrogen.

[0156] In one example of implementation, the process according to the invention may include controlling the chemical nature of the atmosphere within the enclosure during and / or after the reaction step.

[0157] For example, the atmosphere of the enclosure may be devoid of CO2 and / or O2. The atmosphere within the reaction enclosure may then include dinitrogen (N2).

[0158] According to an alternative, the atmosphere within the reaction enclosure may include a neutral gas, for example argon (Ar).

[0159] Such an atmosphere makes it possible in particular to limit the oxidation of the metal powder obtained during the cooling stage.

[0160] Passivation step

[0161] In one example of implementation, the process includes a step of passivating the metal powder.

[0162] Such a passivation step makes it possible to generate an oxide film on the surface of the metal powder particles.

[0163] Such an oxide film limits subsequent oxidation of the powder, thereby promoting its preservation and, if necessary, its processing. This passivation step results in the treated metal powder exhibiting reduced reactivity and improved stability.

[0164] The passivation step in the process may include a step of applying a passivation gas to the metal powder.

[0165] The passivation gas may comprise nitrogen, oxygen in a content between 0.00001 wt.% and 0.005 wt.% and water vapor in a content between 0.00001 wt.% and 0.001 wt.%.

[0166] For example, the passivation gas may comprise nitrogen, oxygen in a content between 0.00001 wt.% and 0.0001 wt.% and water vapor in a content between 0.00001 wt.% and 0.0003 wt.%.

[0167] Recovery stage

[0168] In one example of implementation, the process may include a step of recovering the metal powder.

[0169] Such a step can be carried out under a neutral atmosphere.

[0170] Such a step may include dismantling the device

[0171] By "neutral atmosphere" is meant an atmosphere which will not have any action on the powder, for example an atmosphere which will not induce its degradation or oxidation.

[0172] By way of example, such an atmosphere may include dinitrogen.

[0173] By way of example, such an atmosphere may include a neutral gas, for example of argon (Ar).

[0174] Preferably, such an atmosphere may not include dioxygen, water or other organic solvents.

[0175] In one example of implementation, the process may include a step of recovering a residual gas at the end of the reaction step.

[0176] In one example of implementation, the process may include a washing step.

[0177] For example, the washing step includes a substep for mixing the residual gas recovered with a washing solution having a pH greater than 7 (basic washing solution), for example between 7 and 14.

[0178] For example, the washing step includes a substep for neutralizing at least one chemical species present in said recovered residual gas.

[0179] Such a basic washing solution may be a solution comprising sodium hydroxide or alcoholic potassium hydroxide. A chemical species capable of being neutralized may be hydrochloric acid (HCl), hydrogen fluoride (HF), and / or a metal halide that did not react during the reaction step of the process.

[0180] Device according to an example of an embodiment of the invention:

[0181] The process for manufacturing the metal powder can be implemented in a device for manufacturing a metal powder, for example as shown in [Fig.1] and [Fig.2].

[0182] Figures 1 and 2 schematically illustrate in a semi-assembled manner a device 1 for manufacturing a metal powder, according to an example of an embodiment of the present invention, in overall view ([Fig.1]) and in cross-section ([Fig.2]).

[0183] Such a device for manufacturing metal powder herein comprises:

[0184] - an enclosure 11 comprising an inlet 14 configured to inject a mixture gaseous in the enclosure, and an outlet 15 configured to evacuate residual gas and metallic powder out of the enclosure, - a recuperator 13 comprising an inlet 16 in fluidic communication with the outlet 15 of the reaction enclosure, - an outlet 17 configured to extract the residual gas out of the recuperator, and - a bottom 136 configured to collect the powder obtained, the recuperator comprising a tubular element 132 forming a baffle, configured to slow down the residual gas and metallic powder from the enclosure.

[0185] Each element of the metal powder manufacturing device 1 has an axis of axial symmetry around the X axis.

[0186] The enclosure 11 of the metal powder manufacturing device 1 may include at least one cylindrical tube.

[0187] In the present embodiment, the cylindrical tube comprises several sections: a first cylindrical tube 110, a second cylindrical tube 111 and a third cylindrical tube 112.

[0188] For example, the first cylindrical tube 110, the second cylindrical tube 111 and the third cylindrical tube 112 are coaxial.

[0189] Here, the second cylindrical tube is arranged between the first cylindrical tube and the third cylindrical tube.

[0190] The first cylindrical tube 110 and the second cylindrical tube 111 can be connected by a first insert 115.

[0191] The second cylindrical tube 111 and the third cylindrical tube 112 can be connected by a second insert 116.

[0192] The device 1 may include a plug 114 configured to obstruct an upper end of the enclosure 11. In the present embodiment, the Plug 114 obstructs an upper end of the first cylindrical tube 110, thus allowing an upper section of the enclosure 11 to be obstructed.

[0193] The plug 114 may include a first orifice constituting an inlet 14 of the enclosure 11.

[0194] The first orifice constituting an inlet 14 of the enclosure 11 can be configured to receive an injection rod.

[0195] In the present embodiment, a ring 113 can be placed on the plug 114 and configured to compensate for a difference in diameter between the first orifice constituting an inlet 14 of the enclosure 11 and an injection lance.

[0196] The device 1 may include a tray assembly 12 configured to obstruct a lower end of the enclosure 11. In the present embodiment, the tray assembly 12 obstructs a lower end of the third cylindrical tube 112, thus making it possible to obstruct a lower section of the enclosure 11, located opposite the upper section obstructed by the plug 114.

[0197] The tray assembly 12 may include a base 121.

[0198] The base 121 of the tray assembly 12 may include in its center a second orifice, constituting an outlet 15 of the enclosure 11.

[0199] The bottom 121 of the tray assembly may include a wall which may be flat or curved, capable of retaining the powder or guiding it towards the collector.

[0200] The recuperator 13 may include an inlet 16 through which the residual gas and powder are introduced into the recuperator.

[0201] The input 16 of the reclaimer 13 is connected to the output 15 of the enclosure 11.

[0202] The receptacle 13 may include a bottom 136 configured to retain the metal powder.

[0203] In the present embodiment, the base 136 includes a wall which can be flat or curved, capable of retaining the powder.

[0204] The reclaimer 13 may include a side wall 135 extending from the bottom 136.

[0205] The side wall 135 of the recuperator 13 includes at least one hole constituting an outlet 17 configured to extract the residual gas out of the device.

[0206] The recuperator 13 includes a baffle, configured to slow down the residual gas and metal powder from the enclosure, allowing the metal powder to be deposited in the bottom 136 of the recuperator 13, the baffle being surrounded by the side wall of the recuperator 13.

[0207] The baffle includes a first tubular element 22 surrounding the outlet 15 of the enclosure 11.

[0208] The tubular element 122 is fixed to the bottom 131 of the tray assembly 12 delimiting a bottom of the enclosure 11.

[0209] The tubular element 122 is disposed at a distance from the bottom 136 of the collector 13.

[0210] The baffle comprises a second tubular element 132 surrounding the first tubular element 122.

[0211] The second tubular element 132 is fixed to the bottom 136 of the receptacle 13.

[0212] The reclaimer 13 includes a pin 131 which extends from the bottom of the reclaimer to the outlet 15 of the enclosure 11.

[0213] The pawl 131 includes a head oriented towards the outlet 15 of the enclosure 11.

[0214] The head 130 of the pin 131 is configured to direct the residual gas flow between the first tubular element 122 and the bottom 121 of the recovery unit.

[0215] In the present embodiment, the head 130 of the pawl 131 has a conical shape.

[0216] However, other shapes are conceivable, such as an ogive or pyramid shape.

[0217] The pin 131 and its conical head 130 direct the residual gas flow between the first tubular element 122 and the bottom of the recuperator.

[0218] The pin 131 is centered on the axis of the outlet 15 of the enclosure 11.

[0219] In an example of an embodiment in which the method according to the invention would be Implemented in such a powder manufacturing device 1, the device's chamber 11 can be heated to a reaction temperature during the heating step and pressurized to a reaction pressure during the pressurization step. The gas mixture can be injected into the chamber 11 of the device 1 through the chamber's inlet 14.

[0220] The reaction of the halide and dihydrogen from the gaseous mixture can then be carried out in the enclosure 11 of the device, the enclosure 11 being maintained at the reaction temperature and reaction pressure.

[0221] The residual gas and powder produced during the reaction of the metal halide and dihydrogen exits the enclosure 11 through the outlet 15 and enters the recuperator 13 through the inlet 16.

[0222] The path of the residual gas flow in the recuperator 13 is highlighted by arrow F in figures 1 and 2.

[0223] After passing between the first tubular element 122 and the bottom 136 of the recuperator, the residual gas flow flows between the first tubular element 122 and the second tubular element 132, then between the second tubular element 132 and the bottom 121 of the tray assembly 12.

[0224] Finally, the residual gas flow is extracted from the recuperator 13 through an outlet 17 formed by the holes in the side wall 135 of the recuperator.

[0225] The manufactured metal powder settled in the bottom 136 of the recuperator 13, due to the slowing of the gas flow caused by the baffle comprising the first tubular element 122 and the second tubular element 132.

[0226] According to one embodiment, all the parts of the device for manufacturing a metal powder 1 are made of a metal Me identical to the metal of the prepared metal powder. For example, when a process for preparing molybdenum powder is implemented in a device for manufacturing a metal powder 1, all the parts of the device are then made of molybdenum.

[0227] System according to an example of an embodiment of the invention:

[0228] The device for manufacturing a metal powder 1 can be included in a system 2, the system being able to implement the process.

[0229] Fig. 3 schematically illustrates such a system according to an example of an embodiment of the invention.

[0230] A system 2 may include a chamber 21 configured to be hermetically sealed. The chamber 21 may include an inlet 29 in a cover 27 and an outlet 30. The chamber 21 may also include a bottom 28 and side walls 31.

[0231] Chamber 21 of system 2 may include several functional zones, for example a preheating zone A, a heating zone B, and a pumping zone C.

[0232] The chamber 21 of the system 2 may include a heating means 22 configured to heat the device for manufacturing a metal powder 1.

[0233] By way of example, the heating means 22 includes an induction coil disposed within the chamber 21 and around the device for manufacturing a metal powder 1.

[0234] The system 2 may include a pump 23 configured to modulate a pressure in the chamber 21, the pump 23 being able to be connected to the outlet 30 of the chamber.

[0235] The system 2 may include a device for manufacturing a metal powder 1 disposed inside the chamber 21. For example, the device 1 may be held in the chamber 21 by means of a support 26. The inlet 15 of the enclosure 11 of the device 1 may be in fluidic communication with the injection lance 25. The outlet 17 of the receptacle 13 of the device 1 is in fluidic communication with a volume of the chamber 21.

[0236] System 2 may include a gas circuit comprising: • a first power supply line Ll, • a second L2 power supply line, • a third supply line L3 in fluidic communication with an injection lance 25, • a mixer 24 configured to mix a first gas supplied by the first supply line L1 and a second gas supplied by a L2 feed line, and supply a gaseous mixture, the 24 mixer including: • an initial fluidic communication entry with the first power supply line Ll, • a second fluidic communication input with the second power supply line L2, • an output in fluidic communication with the third supply line L3, the third supply line L3 also being in fluidic communication with an injection lance 25 configured to inject the gaseous mixture produced by the mixer 24 into a chamber 11 of a device for manufacturing a metal powder 1, through an inlet 14 of this chamber 11.

[0237] The gas circuit of system 2 may also include a fourth supply line L4, in fluidic communication with the injection lance 25.

[0238] When the process for manufacturing a metal powder is implemented in this system, the first feed line L1 can be configured to supply the first gas comprising a metal halide, and the second feed line L2 can be configured to supply the second gas comprising dihydrogen. The mixer 24 can be configured to mix the first gas comprising a metal halide and the second gas comprising dihydrogen, thus providing a gas mixture. The third feed line L3 of the gas circuit of system 2 is configured to carry the gas mixture from the mixer 24 to the metal powder manufacturing device 1. The gas mixture can be injected into the reaction chamber 11 of the metal powder manufacturing device 1, through the inlet 14 of the chamber 11, by means of the injection lance 25.

[0239] The heating means 22 of system 2 allows the reaction chamber 11 of the device for manufacturing a metal powder 1 to be heated to a reaction temperature.

[0240] The pump 23 of system 2 allows the system 2 to be evacuated and, together with the gas circuit, the chamber 21 and therefore the enclosure 11 and the receiver 13 of the device for manufacturing a metal powder 1 to be brought to the reaction pressure.

[0241] The reaction step of the metal halide with dihydrogen can then take place in the reaction chamber 11 of the device for manufacturing a metal powder 1, maintained at the reaction temperature by the heating means 22 and maintained at the reaction pressure by the pump 23.

[0242] During the reaction step, the metal powder and a residual gas are produced in the enclosure 11 of the device for manufacturing a metal powder 1.

[0243] The metal powder and residual gas can be extracted through an outlet 15 of the enclosure 11 to the recuperator 13 through an inlet 16.

[0244] The gravity deposition step can take place in the receiver 13. The configuration of the first tubular element 122, forming a first baffle, and the second tubular element 132, forming a second baffle, in the receiver 13 induces a slowing of the velocity of the residual gas carrying the metal powder. The metal powder then settles by gravity into the bottom 136 of the receiver 13, and the residual gas is extracted from the receiver 13 to the chamber 21 of the system 2 via at least one outlet 17. The residual gas can be extracted from the chamber 21 of the system by the pump 23.

[0245] After stopping the injection of the gas mixture into the device for manufacturing a metal powder 1, and during the cooling and re-entry to ambient pressure steps, a passivation gas can be supplied by the supply line L4 and injected into the enclosure 11 of the device, by the injection lance 25.

[0246] System 2 may also include a gas scrubber in fluidic communication with the pump 23. Such a gas scrubber (not shown in the figures) may be disposed downstream of the pump 23 and may be configured to neutralize at least one chemical species present in said residual gas.

[0247] The device 1 for manufacturing a metal powder can be easily extracted from the system 2, for example by removing the cover 27 of the chamber 21. Extraction of the manufacturing device 1 from the system 2 can be carried out when the chamber 21 is at ambient temperature after a cooling step of the chamber 21, and when the chamber 21 is at ambient pressure, after a step of restoring the chamber 21 to ambient pressure. The collector 13 of the device 1 for manufacturing a metal powder can then be opened to recover the metal powder.

[0248] Example: manufacturing molybdenum powder in a device according to an exemplary embodiment of the invention

[0249] A device for manufacturing a metal powder as described above, made of molybdenum, is cleaned in an ultrasonic bath to remove any impurities. The device is then baked at 200°C for 8 hours, followed by degassing at 1600°C.

[0250] The device is then placed in a chamber of a system as described above. The device is heated to a reaction temperature of 1000°C by an induction coil and the chamber of the system is brought to a reaction pressure of 350 mbar.

[0251] Molybdenum hexafluoride (MoF6) is supplied to a mixer at a flow rate of 100 sccm via a first feed line. Dihydrogen is supplied to the mixer at a flow rate of 600 sccm via a second feed line. The ratio of the flow rate of The ratio of dihydrogen to MoF6 flow rate is thus 6. The gas mixture produced by the mixer is introduced into the metal powder manufacturing device, maintained at a reaction temperature of 1000°C and a reaction pressure of 350 mbar for 4 hours. The introduction of MoF6 into the device is then stopped. To cool the device, the heating is stopped and the reaction pressure is maintained. During cooling, a stream of hydrogen is introduced into the device. Once the device reaches ambient temperature, the hydrogen flow is stopped, and the reaction vessel is purged of hydrogen. The powder, located in the condenser, then undergoes a passivation step for 60 minutes using a nitrogen stream introduced into the device containing 0.0003 wt.% water vapor and 0.0001 wt.% oxygen. The device is then brought to ambient pressure and removed from the system. The device is then placed in a neutral atmosphere containing nitrogen but no oxygen or moisture. A 100 g sample of powder is recovered, packaged, and ready for analysis.

[0252] The process made it possible to obtain a yield of 90% (ratio between the mass of molybdenum powder recovered and the mass of molybdenum injected as MoF6 via the first gas).

[0253] The powder obtained here has an average particle diameter of 1.5 pm.

[0254] The particle size distribution is relatively homogeneous, as shown in the graph presented in [Fig.4].

[0255] The powder particles are relatively spherical in shape and regular in appearance, as shown in the particle sample presented in [Fig. 5] (optical microscopy image). The powder particles in this sample have an average diameter of 1.11 pm.

[0256] Finally, the powder then has in this example a molybdenum purity of 99.9999% (6N).

Claims

Demands

1. A process for manufacturing a metal powder of metal Me, the process comprising at least the following steps: - A step of supplying a first gas comprising a metal halide comprising a metal Me; - A step of supplying a second gas comprising dihydrogen; - A step of mixing the first gas and the second gas producing a gaseous mixture; - A step of heating a reaction vessel to a temperature, referred to as the reaction temperature, of between 950°C and 3000°C; and - A step of pressurizing the reaction vessel to a pressure, referred to as the reaction pressure, of between 200 mbar and 500 mbar; - A step of injecting the gaseous mixture into the reaction vessel maintained at the reaction temperature and reaction pressure;- A reaction step of the halide and dihydrogen of the gaseous mixture, in the reaction chamber maintained at the reaction pressure, and at the reaction temperature, producing the metallic powder of metal Me.;

2. A method according to claim 1, comprising a step of gravity deposition of the metal powder into a collector disposed downstream of the reaction chamber.

3. A method according to claim 2, wherein the gravity deposition step includes a step of pressurizing the recuperator to a pressure, called the recovery pressure, the recovery pressure being lower than the reaction pressure.

4. A method according to any one of claims 2 or 3, comprising a step of cooling the enclosure from the reaction temperature to ambient temperature, and a step of returning the enclosure to ambient pressure, after the gravity deposition step.

5. A method according to any one of claims 1 to 4, wherein the metal halide has the formula MeyXz, where Me is molybdenum, rhenium, tungsten or iridium; X is fluorine, chlorine, bromine or iodine; y and z are each an integer equal to or greater than 1.

6. A process according to claim 5, wherein the metal halide is molybdenum hexafluoride (MoF6).

7. A process according to any one of claims 1 to 6, comprising a step of passivating the metal powder, the passivation step comprising a step of applying a passivation gas to the metal powder, the passivation gas comprising nitrogen, oxygen in a content of between 0.00001 wt.% and 0.005 wt.% and water vapor in a content of between 0.00001 wt.% and 0.0003 wt.%.

8. A process according to any one of claims 1 to 7, comprising: - a step of recovering a residual gas at the end of the reaction step; and - a washing step, the washing step comprising a substep of mixing the recovered residual gas with a washing solution having a pH greater than 7, and a substep of neutralizing at least one chemical species present in said recovered residual gas.

9. A method according to any one of claims 1 to 8, wherein the first gas is injected at a first flow rate of between 50 sccm and 150 sccm.

10. A process according to any one of claims 1 to 9, wherein the gas mixture obtained in the step of mixing the first gas and the second gas comprises a volume ratio of dihydrogen to metal halide of between 3 and 30.

11. Metallic powder, characterized in that it comprises a metallic species Me, in a content of between 99.9999 wt.% and 100 wt.% (relative to the total mass of the powder).

12. Device (1) for manufacturing a metal powder comprising - a chamber (11) including an inlet (14) configured for injecting a gas mixture into the chamber (11), and at least one outlet (15) configured for venting residual gas and metal powder from the chamber (11), and

13.

14.

15.

16. - a recuperator (13) comprising an inlet (16) in fluidic communication with at least one outlet (15) of the enclosure (11), at least one outlet (17) configured to extract the residual gas out of the recuperator (13), and a bottom (136) configured to collect the metal powder obtained, said recuperator (13) being configured to slow down the residual gas and metal powder from the enclosure (11). Device (1) according to claim 12, wherein the reclaimer (13) comprises at least one baffle. Device (1) according to claim 13 in which the baffle comprises a first tubular element (122) and a second tubular element (132). Device (1) according to any one of claims 12 to 14, wherein at least a part of the enclosure (11) and / or the collector (13) are made of a Me metal, the Me metal being identical to the metal of the prepared metal powder. System (2) comprising: a device for manufacturing a metal powder (1) as defined in any one of claims 12 to 15, a chamber (21) configured to be hermetically sealed, the device for manufacturing a metal powder (1) being disposed in the chamber (21), a heating means (22) disposed in the chamber (21), and configured to heat said device for manufacturing a metal powder (1), a pump (23) configured to modulate a pressure in the enclosure (11) of the device (1), a gas circuit comprising: • at least one first supply line (Ll) to a first gas, • a second supply line (L2) with a second gas, • a mixer (24) configured to mix the first gas and the second gas and provide a gaseous mixture, the mixer (24) comprising: • a first inlet in fluidic communication with the first supply line (L1), • a second fluidic communication input with the second supply line (L2), • an output in fluidic communication with an input (14) of the enclosure (11) of the device for manufacturing a metal powder (1) by means of an injection lance (25) configured to inject the gas mixture into the enclosure (11) of the device for manufacturing a powder (1).

17. System (2) according to claim 16, wherein the heating means (22) comprises an induction coil, the induction coil being disposed within the chamber (21) and around the device for manufacturing a metal powder (1).

18. System 2 according to any one of claims 16 or 17, wherein the pump (23) is configured to recover residual gas at an outlet (30) of the chamber (21).

19. System (2) according to claim 18, comprising a gas scrubber in fluidic communication with said pump (23) recovering the residual gas, downstream of the chamber (21), configured to neutralize at least one chemical species present in said residual gas.

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