FR2980126A1 - METHOD AND INSTALLATION FOR PROCESSING A LOAD - Google Patents

Abstract

The invention relates to a method for treating a charge by introducing said charge into a homogenized gas flow (27), in which a gas flow (5) is generated at a temperature of greater than or equal to 1200 ° C, said gas flow (5) having a velocity at least two times greater than or equal to the rate of introduction of said feed into said homogenized gas flow (27). According to the invention, the following successive steps are carried out: a) during a time interval tau, a deformation is applied to said gaseous flow (5) thus generated to form a flow having an annular section, b) said charge is injected in the space delimited by the homogenized gas flow (27) obtained by said gaseous flow (5) thus shaped, and c) said charge is allowed to react in said homogenized gas flow (27).

Description

The present invention relates to a method for treating a charge in a high temperature and high velocity gas flow, as well as an installation for its implementation. It relates in particular to a method for injecting all of a charge of solid, liquid or gaseous materials into the heart of a gas flow of average temperature greater than 1200 ° C and of speed at least twice the speed of d introduction of the charge into this gas flow. It is known that the penetration of multiphase fluids in a gas flow at high temperature and at high speed, and more particularly of solid materials in the form of particles conveyed by a carrier gas, presents great difficulties because of the high viscosity of the medium, although it is gaseous. For example, there are known processing devices for injecting, perpendicularly to a plasma flow, a charge consisting of solid particles. This type of device is typically applied to the plasma sprayed surface treatment. Now, it is found that only a fraction of the particles actually enter the plasma flow to be treated there, another fraction not penetrating the plasma flow and the last fraction passing through the plasma flow without being treated. Many technical solutions have been proposed to address this problem of partial processing of loads.

Patent GB 2461747 discloses a method and a device for thermal spraying, in which a port for introducing a gas is placed opposite a powder injection port with respect to a plasma flow. . Thus, a gas such as Argon, is introduced opposite an injection of powders made perpendicularly to the plasma flow, so as to push towards this plasma flow, the particles that would pass through the plasma, thus improving the material balance of the treated particles in this plasma flow. US 2010/0323117 also discloses an injection mode into a guided plasma flow in a conduit. However, the latter does not eliminate the difficulty of real penetration of the particles in the plasma flow. Also known from WO 2010/107484 is a hybrid nozzle for use in a plasma spray gun, particularly for plasma sputtering silicon to form semiconductor devices. This document shows that parietal injections in a guided plasma flow in a conduit can lead to an inhomogeneous treatment of the powder material. All these devices of the state of the art have one or the other of the following disadvantages: a penetration into the plasma of only a fraction of the particles to be treated, and therefore a material balance, considered as the ratio from the mass of treated particles to that of injected particles, limited to about 60%, - an inhomogeneous treatment which does not take into account the particle size distribution, in the case of solids, and which necessarily exists in any prior conditioning. The present invention aims to overcome these various drawbacks by proposing a method and a facility for treating a charge, simple in their design and in their operating mode, ensuring an interaction 30 of the totality of the injected charge with the gas flow at high temperature and high speed. Another object of the present invention is to obtain a mixture of gas flow at high temperature and high speed / single or multiphasic fluid such that the thermochemical treatment of a particle charge 35 is substantially equivalent for all the particles making up this charge, regardless of their particle size distribution, and whatever the characteristics or the degree of homogeneity of this gas flow. Yet another object of the present invention is a mixture of high temperature and high speed gas flow / particles made in a dense phase, that is to say with a mass ratio of particle flow / high gas flow, so optimize energy and chemical balances. For this purpose, the subject of the present invention is an installation for treating a charge by introducing said charge into a homogenized gas flow, said installation comprising an assembly for generating a gas flow at a temperature greater than or equal to 1200 ° C. said gas flow having a velocity at least two times greater than or equal to the rate of introduction of said feed into said homogenized gas flow.

According to the invention, this installation also comprises: a forming assembly of said gas flow comprising an enclosure delimiting an internal volume and an obstruction body placed at least partially in this internal volume so as to define an annular passage channel; the gaseous flow between the inner face of the chamber and the outer face of said obstruction body, said annular channel extending along said obstruction body, said obstruction body having a front face for receiving said gas flow generated by said assembly for generating a gaseous flow, and deflecting said flow towards said annular channel, and said plant comprises means for injecting said charge into a homogenized gas flow from the passage of said gaseous flow into said annular channel. Accordingly, the present invention is primarily concerned with the injection, into a high temperature, high velocity flow, of solid powdery materials, aggregates of nano-powders, liquid materials, whether or not charged with particles. solids, and gaseous flow with lower injection difficulties, but having to undergo a chemical reaction in said flow of high temperature and high speed.

The term "gaseous flow" is understood to mean plasma flows such as plasma jets from a plasma torch but also flames. Non-transferred arc plasma represents, in particular, the most extreme temperature, velocity and viscosity conditions in thermochemical processes. Accordingly, the jet, or stinger, plasma will preferably be generated by an untransfected arc plasma torch. The presence of the obstruction body, which forms an obstacle in the linear propagation of the gas flow at high temperature and high speed, has the effect of breaking the spatial and temporal inhomogeneity of the gas flow by conferring on it an annular spatial distribution. or substantially annular depending on the shape of the obstacle and / or the inner wall of the enclosure. Thus, the gas flow is advantageously homogenized in terms of temperature and speed. There is indeed a redistribution of velocities and temperatures in this annular or substantially annular spatial distribution. The gas flow from the annular channel is thus a homogenized gas flow. By the term "homogenized gaseous flow" is meant a distribution of the velocities and temperatures of this flow which does not exceed more or less 20% (20%) of the average values of velocity and temperature of this flow. In various particular embodiments of this load processing installation, each having its particular advantages and capable of numerous possible technical combinations: said obstruction body comprises said means for injecting said load. Preferably, this obstruction body having a rear face, placed downstream of its front face in the direction of propagation of the gas flow, at least a part of the injection means of said load, is placed on said rear face . In an even more advantageous embodiment, said rear face comprises at least one injection orifice, preferably centrally located with respect to said annular channel, the injection means being placed inside the obstruction body. by being connected to said at least one injection port. said load injection means are injection means for axial axial movement of the load within said enclosure. The charge is thus extracted from the injection means along helical paths in the direction of propagation of the gas flow, thus comprising a rotation component to increase their residence time in the gas flow coming from the annular channel, which allows to adjust the treatment "in flight" of the load. This residence time is typically in the range of a few milliseconds to more than 10 milliseconds.

In addition, this charge comprising particles, the rotary component induces distinct trajectories of the particles in the extraction zone of the obstruction body, which is placed downstream of the annular channel, according to their respective particle sizes. Advantageously, this method of extraction induces on the one hand a distribution of the particles in a larger volume before treatment in the gas flow from the annular channel, which forms a homogenized gas flow and on the other hand, induces residence times particles optimized in this gas flow. In fact, particles of high particle size, and therefore of high mass, are associated with helicoidal trajectories of larger diameter because of the centrifugal force associated with their mass, and consequently, necessarily longer residence times in the gas flow. only for particles of smaller particle size. In conclusion, this mode of injection has a triple advantage: a) treat the entire load, b) increase the residence time in the gas flow at high temperature and high speed of the load, in particular particles of high particle size , which actually require a longer treatment time than that of the particles of smaller particle size, hence a treatment time adapted to the particle size distribution, c) spatially distribute the particles in the homogenized high temperature flow after shaping according to their mass and thus optimize the energy transfer gas flow at high temperature and high speed / particles. said obstruction body comprising an internal volume, said charge injection means comprise one or more ducts for feeding said charge into said internal volume, said supply ducts being arranged tangentially or substantially tangentially with respect to said volume; internal, said supply conduits being connected at one of their ends to said enclosure and at their other end to said obstruction body. By way of example, these supply ducts may be four in number. said gaseous flow having an axis of propagation and said obstruction body having a principal axis of symmetry, said axes being merged, said forming assembly comprising an input port for the introduction of said gaseous flow generated by said together to generate a gas flow, the obstruction body can project from this input port and therefore have a portion placed in front of this chamber in the direction of propagation e gas flow at high temperature and high speed. said obstruction body having a rear face, the inner face of said enclosure extends downstream from said rear face to form an outlet section of said shaping assembly, said obstruction body having a rear face, said portion of the inner face of the enclosure placed downstream of said rear face has a narrowed shape so as to ensure a new shaping of said homogenized gas flow at the outlet of said annular channel. Preferably, said portion has a truncated conical or pseudo-conical shape. Advantageously, the half-angle at the top of the cone is between 5 ° and 30 ° so as to form a gaseous flow having a shape whose section has a circular or substantially circular shape. Thus, in addition to a primary charge processing function, the homogenized gas stream thus shaped, i.e. having an annular cross-section, has a gaseous wall of high viscosity which confines the all of the charge from the injection means, at room temperature, prior to its necessary penetration into the reconstituted homogenized gas flow downstream of the obstruction body. In other words, since the homogenized gaseous flow has an annular shape at the outlet of the annular channel, this homogenized gaseous flow traps all of the charge injected into its core, forming around the charge a gaseous wall of high viscosity. The ring-shaped homogenized gas flow is then again shaped to form a homogenized gaseous flow of full section, the entire charge that was trapped, can then react in homogenized speed and temperature fields ensuring the integral treatment of the charge. the front face of said obstruction body has a shape of a spherical or ovoid cap, at least said front face of said obstruction body is made of copper or aluminum; said assembly for generating a gas flow comprises at least one selected element; in the group comprising a non-transferred arc plasma torch, a burner generating a melting zone where the charge is heated and melted, an oxy-burner, an oxy-burner with an adjustable flame, a torch and combinations thereof, obstruction comprises cooling means, preferably said obstruction body comprises a double wall connected to a cooling circuit so as to ensure the cooling of said obstruction body and in particular of its front face. the injected charge can be gaseous, liquid or solid in the form of particles, sludge or nanoparticle aggregates. In the case of solid particles, the carrier gas is a neutral gas, of the argon type, but can also be a gas. reagent which participates in the thermochemical treatment of particles, depending on the desired application. By way of example, this gas may be CO2 for gasification applications. Preferably, a gaseous feedstock is transported under pressure and emerges from the injection means directly into the gaseous flow coming from the annular channel. A liquid charge (charged in particles or not), as for it, is transported under pressure then atomized in the form of fine droplets to be introduced in the gas flow coming from the annular channel. Alternatively, this liquid charge (charged in particles or not) is transported under pressure, then injected in continuous thread to be atomized by the gas flow from the annular channel while being treated thermochemically. A solid charge, in the form of particles or in the form of particles or aggregates of nanoparticles, is transported by carrier gas, the carrier gas / particle mixture being treated in the gas flow from the annular channel. Preferably, the ratio of the mass of the feedstock to the carrier gas mass is greater than 20 to limit the flow rate of the generally cold or low temperature carrier gas, and thus limit the cooling of the high temperature and high temperature gas flow. velocity from the annular channel. The carrier gas may be a neutral gas or a reactive gas, depending on the desired application. The invention also relates to a method of treating a charge by introducing said charge into a homogenized gas flow, in which a gaseous flow is generated at a temperature greater than or equal to 1200 ° C., said gas flow having a speed of at least two times greater than or equal to the rate of introduction of said charge into said homogenized gas flow. According to the invention, the following successive steps are carried out: a) during a time interval T, a deformation is applied to the gas flow thus generated to form a flow having an annular section, b) said charge is injected into the the space delimited by the homogenized gas flow obtained by said gaseous flow thus shaped, and c) said charge is allowed to react in said homogenized gas flow. The treatment method of the invention therefore aims to introduce, preferably continuously, in a homogenized gas flow at high temperature and high speed with respect to the rate of introduction of the charges in this gaseous flow, mineral, organic fillers. or mixtures thereof, consisting of particles, aggregates of solid nanoparticles. This treatment process can also be applied to liquid and gaseous charges, charged or not with particles or aggregates of nanoparticles. By way of examples, oxides may be injected to reduce them, for example metal oxides to make rare or high purity metals and other noble alloys; or inject carbonaceous or organic products to gasify them in order to subsequently recover a synthesis gas by combustion, for the production of fuel, or even for chemical synthesis; or inject solid waste, liquid (loaded or not), slurries ("slurrys") to destroy them or reduce their toxicity by dissociation and molecular recombination; even make them inert. The granulometric range that the injection means allows to introduce preferably extends from micrometer to about 1000 micrometers (1 to 1000pm), depending on the desired application. For purely illustrative purposes, the oxide to be reduced may be silica or quartz. Advantageously in this case, the recommended particle size will be in the range 1 to 1000 μm. In various particular embodiments of this method of treating a load, each having its particular advantages and capable of numerous possible technical combinations: in step b), said charge is continuously introduced into the space delimited by the gaseous flow homogenized, in step b), said charge is introduced so as to give axial axial movement to the charge in the space defined by the homogenized gas flow. Preferably, the charge to be injected is directed downstream in the direction of propagation of this homogenized gas flow. This filler then mixes with the homogenized gas flow to be treated thermo chemically "in flight" in a melting / vaporization process. in step c), a new deformation is applied to said homogenized gas flow to form a gas flow of circular or substantially circular solid section; after step c), the particles, if not completely treated, are recovered in a crucible; subjected to a stopping point at the gas flow at high temperature and high speed so as to complete the melting / vaporization process. Advantageously, according to the method of the present invention, all of the feedstock introduced is thermochemically treated in a non-selective manner regardless of the characteristics of physical inhomogeneity of this feedstock.

The invention will be described in more detail with reference to the accompanying drawings in which: - Figure 1 shows schematically a sectional view of a shaping assembly of a gas flow in a load processing facility according to a particular embodiment of the invention, this forming assembly being connected to a non-transferred arc plasma torch, the homogenized gas flow being partially represented for the sake of clarity; FIG. 2 is a side view of the enclosure and the obstruction body, showing the conduits for feeding the particles by carrier gas; FIG. 3 is a side view of the enclosure and the obstruction body in a charge processing installation according to another embodiment of the invention; Figure 1 schematically shows a sectional view of a shaping assembly of a gas flow in a load processing facility according to a preferred embodiment of the invention. This set of shaping of the flow comprises an axisymmetric chamber 1 delimiting an internal volume in which are placed an obstruction body 2 and supply ducts of products to be treated 3 connected to the obstruction body 2. The obstruction body 2 has a front face 4 which has the shape of a spherical cap. Preferably, at least the front face 4 of the obstruction body 2 is made of copper. This front face 4 is intended to receive a plasma flow of cylindrical section 5 generated by a plasma torch. The end 6 of this plasma torch is assembled at the input port of the axisymmetric chamber 1 so as to be in fluid communication with this chamber 1.

The plasma flow 5 which propagates along the axis of axial propagation 7, typically has a temperature of the order of 3000 ° C and a speed greater than 100 m.s-1. The obstruction body 2 has a double wall for cooling, which is connected to a cooling circuit (not shown).

The obstruction body 2 may, however, have any other shape, for example ovoid, with respect to its front face which faces the propagation axis plasma flow 7. A pulverulent solid charge 8 transported by means of FIG. a carrier gas is introduced continuously by at least two metal pipes 9 for feeding the charge to be treated inside the obstruction body 2. In the embodiment described, four pipes 9 for supplying the load are provided, which are distributed angularly at 90 ° around the periphery of the obstruction body 2 (Figure 2).

Each feed pipe 9, which will be brought into contact with the plasma flow 5, is protected by a tube 10 concentric with said pipe 9, the annular space 11 between the wall of the pipe 10 and the pipe 9 being traversed by a cooling fluid under pressure, the flow ensures the mechanical strength at high temperature of the tube 10 as the pipe 9. Advantageously, the cooling fluid is water. In addition, the assembly formed by the pipes 9 and the tubes 10 provides support for the obstruction body 2 and its positioning. The obstruction body 2 is placed inside the chamber 1 so that its axis of symmetry coincides with the axis of propagation 7 of the plasma flow 5. The solid powdery charge 8, transported in the pipes 9 by means of a carrier gas, is brought into an internal chamber 12 of the obstruction body 2. The volume of this inner chamber 12 is partly delimited by a wall 13 having a circular section that is progressive in the direction of a injection port 14 placed on the rear face 15 of the obstruction body 2, with which it is connected. This wall 13 here has a section of circular shape that is reduced towards this injection port 14. This wall 13 could have any other shape, for example, be of elliptical section. The inner chamber 12 is accordingly in fluid communication with the injection port 14, also of circular section. The main axis of the internal chamber 12 is, moreover, also coincident with the propagation axis 7 of the plasma flow 5. The powdery solid charge 8, transported by carrier gas, is vortexed into the internal chamber. 12. The evolutionary form 13 of the internal chamber 12 with reduction of its section towards the injection orifice 14 leads to the reinforcement of the vortex effect up to this injection orifice 14. This vortex effect is further increased by the presence of grooves, or grooves, 16 made in the wall 13 of the inner chamber near and to the injection port 14. These flutes 16 have a helical shape. Advantageously, the area of the section of the injection orifice 14 is at least substantially equal to the cumulative area of the sections of the pipes 9, to prevent any accumulation of material in the internal chamber 12 of the obstruction body 2. Under these conditions, there is, at the outlet of the chamber 12, at the injection orifice 14, a two-phase flow in which the solid particles follow helicoidal paths whose diameters, measured perpendicular to the axis of propagation 7 of the plasma flow 5, are related to the individual mass of each of these particles. Thus, the heavier particles have helicoidal trajectories of larger diameters. The obstruction body 2 placed inside the enclosure 1 defines an annular channel 17 for passing the gas flow between the internal face of a first wall portion 18 of the enclosure 1 and the outer face of the this obstruction body 2, this annular channel 17 extending along the obstruction body 2. This annular channel 17 advantageously has a substantially constant section in the direction of propagation of the plasma flow thanks to the curved shape of the first wall portion 18 of the enclosure 1.

The plasma flow 5 which is deflected from its propagation trajectory by the front face 4 of the obstruction body 2 placed inside the enclosure 1, is guided inside the annular channel 17 in which it undergoes a shaping. This shaping advantageously makes it possible to redistribute all the speeds of the gaseous flows and to obtain a homogenized gas flow 27 at the outlet of the annular channel 17. In the outlet plane 19 of the first wall portion 18 of the enclosure 1, the homogenized plasma flow is angularly oriented towards the main axis 7, following a conical trajectory imparted by a second wall portion 20 of the enclosure 1. The theoretical peak of the cone is advantageously positioned on the main axis 7 downstream of the rear face 15 of the obstruction device 2 in the direction of the plasma flow 5. The theoretical peak of the cone 21 results from the initial orientation of the homogenized plasma flow in the outlet plane 19, taking into account a half-angle at the apex of the cone in a range of values between 5 ° and 30 °. The second wall portion 20 of the enclosure 1 is however connected to an output port 22 so that this second wall portion 20 has a truncated cone shape. At this output port 22, a voluminal or cylindrical plasma flow 23 is reconstituted, the plasma flow thus having undergone a second shaping to return to its initial shape at the outlet of the plasma torch 6. The particles of helical trajectories at the exit of the injection orifice 14, introduced into a zone at ambient temperature, are "trapped" by the plasma flow of annular section. Indeed, the plasma flow thus formed a first time, has a gaseous wall of high viscosity which confines the entire charge from the injection port 14. The particles that comprises the load to be treated are thus guided until they penetrate the plasma volume flow 23 to be treated thermo chemically "in flight". It will be noted that the coolant circulating in the annular spaces 11, injected by two pipes 9 implanted vis-a-vis the periphery of the obstruction body 2, is collected and then distributed inside this body. obstruction 2 and in particular through a longitudinal duct 24 conveying the coolant towards the front face 4 of the obstruction body 2 so as to cool a wall portion 25 of the front face 4 positioned at a point d stopping the plasma flow 5 from the plasma torch 6. This wall portion 25 of the front face 4 of the obstruction body 2 is in fact the most thermally stressed. From this longitudinal duct 24 and after encountering the wall portion 25, the cooling liquid is distributed in a double wall over the entire obstruction body 2 so as to ensure the cooling of its walls. The return of cooling liquid is effected by the two other pipes implanted vis-a-vis at the periphery of the obstruction body 2. In conclusion, the paths of the coolants are decoupled from the paths of the charge to be treated without it is necessary to provide specific external circuits for the supply of coolant. FIG. 1 also very schematically shows a crucible 26 making it possible to complete the treatment of the particles possibly not completely treated in flight in the homogenized voluminal plasma flow 23 at the outlet of the enclosure 1. FIG. partial sectional view and front of the connection of the pipes 9 and tubes 10 with the inner chamber 12 of the obstruction body 2, the chamber 1 has been omitted for the sake of clarity. The longitudinal axes 28 of the pipes 9 are arranged tangentially to the wall 13 delimiting the internal chamber 12 in a plane perpendicular to the main axis 7. This arrangement of the pipes 9 and their distribution around the chamber 12 allows the vortex injection of the charge to be treated in the inner chamber 12. The machined grooves 16 in the wall 13 are also visible. Means of measurement and control make it possible to know the state of the melting / vaporization process, as well as the good behavior of the elements of the obstruction device 2 which are subjected to the action of the thermal plasma. In one embodiment, the installation described here for the treatment of a load is used as follows: a) operating the cooling of the obstruction device 2 by a cooling liquid under pressure, this coolant being advantageously water, b) commissioning of the non-transferred arc plasma torch 6, c) continuous injection of the charge to be treated and simultaneous treatment of the latter, e) in parallel, complementary treatment of the particles optionally untreated and collected in the crucible 26, f) recovery of gaseous effluents resulting from the treatment, for obtaining the reaction products by subsequent condensation. As a purely illustrative example, an installation for the treatment of an industrial load has the following main characteristics: - diameter of the obstruction body 2 facing the plasma flow: 60 mm, - diameter of the particle transport pipes 9: 6 mm, - particle flow rate: 100 kg / h, and carrier gas flow rate: 5 kg / h.

Claims (16)

REVENDICATIONS1. Plant for treating a charge by introducing said charge into a homogenized gas flow, said installation comprising an assembly (6) for generating a gas flow (5) at a temperature greater than or equal to 1200 ° C, said gas flow (5 ) having a speed at least two times greater than or equal to the rate of introduction of said charge into said homogenized gas flow, characterized in that it also comprises - a shaping assembly of said gaseous flow (5) comprising a chamber (1) delimiting an internal volume and an obstruction body (2) placed at least partially in this internal volume so as to define an annular channel (17) for passage of the gas flow (5) between the internal face of the enclosure (1) and the outer face of said obstruction body (2), said annular channel (17) extending along said obstruction body (2), - said obstruction body (2) having a face advan t (4) for receiving said gas flow (5) generated by said assembly (6) for generating a gas flow and for deflecting it towards said annular channel (17), and comprising injection means ( 12-14, 16) of said charge in a homogenized gas flow (27) from the passage of said gas flow (5) in said annular channel (17). 2. Installation according to claim 1, characterized in that said obstruction body (2) comprises said injection means (12-14, 16) of said load. 3. Installation according to claim 2, characterized in that said obstruction body (2) having a rear face, at least a portion of said injection means (12-14, 16) of said load is placed on said rear face (15). 4. Installation according to claim 3, characterized in that said rear face (15) comprises at least one injection orifice (14), preferably placed centrally with respect to said annular channel (17). 5. Installation according to any one of claims 1 to 4, characterized in that said injection means (12-14, 16) of the load are injection means (12-14, 16) to give a movement helically axial to the load within said enclosure (1). 6. Installation according to any one of claims 1 to 5, characterized in that said obstruction body (2) having an internal volume (12), said injection means (12-14, 16) of the load comprise one or more supply ducts (9) of said charge in said internal volume (12), said supply ducts (9) being arranged tangentially or substantially tangentially with respect to said internal volume (12), said supply ducts ( 9) being connected at one of their ends to said enclosure (1) and at their other end to said obstruction body (2). 7. Installation according to any one of claims 1 to 6, characterized in that said gas flow (5) having an axis of propagation (7) and said obstruction body (2) having a main axis of symmetry, said axes are confused. 8. Installation according to any one of claims 1 to 7, characterized in that said obstruction body (2) having a rear face (15), the inner face of said enclosure (1) extends downstream of said rear face to form an exit section (22) of said shaping assembly. 9. Installation according to any one of claims 1 to 8, characterized in that said obstruction body (2) having a rear face (15), said portion (20) of the inner face of the enclosure (1). ) placed downstream of said rear face (15) has a narrowed shape so as to ensure a new shaping of said homogenized gas flow (27) at the outlet of said annular channel (17). 10. Installation according to claim 9, characterized in that said portion has a truncated conical or even pseudo-conical shape. 11. Installation according to any one of claims 1 to 10, characterized in that the front face (4) of said obstruction body (2) has a spherical or ovoid shaped cap. 12. Installation according to any one of claims 1 to 11, characterized in that said assembly (6) for generating a gas flow comprises at least one element selected from the group comprising a non-transferred arc plasma torch, a burner generating a melting zone where the charge is heated and melted, an oxy-burner, an oxy-burner with adjustable flame, a torch and combinations of these elements. A method of treating a charge by introducing said charge into a homogenized gas flow (27), wherein a gaseous flow (5) is generated at a temperature of at least 1200 ° C, said gas flow (5) having a speed at least two times greater than or equal to the rate of introduction of said charge into said homogenized gas flow (27), characterized in that the following successive steps are carried out: a) during a time interval z, applies a deformation to said gas flow (5) thus generated to form a flow having an annular shaped section, b) said charge is injected into the space delimited by the homogenized gas flow (27) obtained by said gas flow (5) thus shaped, and c) said charge is allowed to react in said homogenized gas flow (27). 14. The method of claim 13, characterized in that in step b) is introduced continuously said charge in the space defined by said homogenized gas flow (27). 15. The method of claim 13 or 14, characterized in that in step c), a new deformation is applied to said homogenized gas flow (27) to form a gaseous flow (23) of circular or substantially circular solid section. . 16. Method according to any one of claims 13 to 15, characterized in that in step b), said charge is introduced so as to give an axial axial movement to this load in the space defined by said flow gaseous homogenized (27).