FR3153001A1 - APPARATUS FOR PRODUCING A SILICON-BASED MATERIAL UNDER VACUUM - Google Patents

Abstract

The invention relates to an apparatus for producing a silicon-based material from quartz and a reducing agent, the apparatus comprising: a reaction chamber (1) for carrying out a chemical reaction using the reactants, the reaction chamber including a sealed enclosure, a tank, and an arc furnace, a condensation chamber (2) for solidifying a chemical compound contained in a gas emitted from the reaction chamber (1), and a conduit (3) for conveying the gas between the reaction chamber (1) and the condensation chamber (2), remarkable in that the condensation chamber (2) further comprises a vibrator for generating vibrations in a side wall (212) of the condensation chamber (2). Figure to be published with the abstract: Fig. 2

Description

APPARATUS FOR PRODUCING A SILICON-BASED MATERIAL UNDER VACUUM FIELD OF THE INVENTION

The present invention relates to the general technical field of the production of a silicon-based material such as silicon (II) monoxide and/or silicon, in particular of 3N purity (99.9% purity) or higher (4N (99.99%), 5N (99.999%), 6N (99.999%), etc.).

More specifically, the invention relates to the continuous production – as opposed to batch production (or “batch” , according to the terminology used in the field of industrial processes) – of a silicon-based material by chemical reduction of quartz in a device including an arc furnace.

BACKGROUND OF THE INVENTION

The high-temperature chemical reaction of quartz reduction can be used to obtain different silicon-based materials, in particular depending on the reducing agents used in this reaction.

• un matériau à base de carbone permet la production de silicium,
• du silicium permet la production de monoxyde de silicium.

For example, the reduction of quartz with:

• a carbon-based material enables the production of silicon,
• silicon allows the production of silicon monoxide.

1. Silicon production

The production of metallic silicon is generally based on the carbothermal reduction of quartz at high temperature and atmospheric pressure.

This thermal reduction of quartz can be achieved by chemically reducing the quartz in the presence of carbon-based reducing agents in an electric arc furnace where a high temperature arc heats the reactants (quartz and reducing agents).

This makes it possible to produce so-called “metallurgical grade” silicon (or “MG-Si” acronym for the Anglo-Saxon expression “ Metallurgical Grade Silicon” ) with a maximum purity of 98-99%.

• en tant qu'élément d’alliage – par exemple dans l'industrie de l'aluminium et de l'acier – ou
• en tant que précurseur – par exemple dans l’industrie photovoltaïque (panneaux solaires), pour les silicones et pour le stockage d’énergie (batterie Lithium).

Metallurgical grade silicon can be used:

• as an alloying element – for example in the aluminium and steel industry – or
• as a pioneer – for example in the photovoltaic industry (solar panels), for silicones and for energy storage (lithium battery).

Technological developments in the fields of photovoltaics and energy storage have led metallurgical grade silicon to become a strategic material.

Therefore, the supply of high purity metallurgical grade silicon at a reasonable cost has become a necessity.

However, conventional metallurgical silicon production devices and processes have many drawbacks such as a high impurity content.

To overcome this drawback, it is possible to use a raw material (quartz) with high purity. However, this solution increases the production cost of the metallurgical silicon produced.

US 11,267,714 proposes another solution consisting of implementing the carbothermic reduction of quartz at high temperature under vacuum. Carrying out the carbothermic reduction of quartz under vacuum makes it possible to promote the evaporation of impurities present in the reactants (quartz and reducing agents) as well as in the newly produced liquid metallurgical grade silicon.

In reference to the FIG. 1 , the apparatus according to US 11,267,714 comprises an electric arc furnace FA and a sealed enclosure E containing the arc furnace FA. This arrangement (sealed enclosure E containing the arc furnace FA) makes it possible to control the pressure at which the carbothermic reduction of quartz is carried out.

However, the embodiments of the apparatus described in US 11,267,714 have certain limitations which make it difficult to use the solution according to US 11,267,714 on an industrial scale for the production of silicon.

2. Production of silicon (II) monoxide

Silicon monoxide (SiO) can be obtained by partial chemical reduction of silicon dioxide (SiO ₂ ) in the presence of silicon (Si) according to the following reaction:

SiO ₂ + Si ⇌ 2 SiO↑

To produce silicon monoxide (SiO) using this reaction, a mixture of silicon (Si) and silicon dioxide (SiO ₂ ) is heated to a sublimation temperature of silicon(II) monoxide (SiO). When the reaction occurs at atmospheric pressure, the sublimation temperature is 1600°C. When the reaction occurs in a vacuum, the sublimation temperature is significantly lower, about 1200°C.

This allows the generation of a gas containing silicon monoxide (SiO) by chemical reduction. This gas is then cooled to a temperature below 800°C. The cooling of the gas containing silicon monoxide (SiO) is carried out quickly to limit the risks of restructuring, by disproportionation, of silicon monoxide (SiO) in the form of silicon (Si) and silicon dioxide (SiO2).

Rapid cooling of the gas containing silicon monoxide (SiO) induces, by condensation, the formation of an amorphous material, (SiO)n.

Such a glassy material based on silicon monoxide (SiO) is commercially available and can be used for various applications in the fields of optics or optoelectronics (deposition of a SiO layer on a support), or in the field of rechargeable lithium-based batteries (manufacture of anodes in particular).

Although not yet realized, the apparatus according to US 11,267,714 could be suitable for the production of silicon monoxide (SiO).

However, the alternative embodiments of the apparatus described in US 11,267,714 have certain limitations which make it difficult to use the solution according to US 11,267,714 on an industrial scale for the production of silicon monoxide.

An aim of the present invention is to provide a method and a device allowing the continuous production of a silicon-based material, such as silicon (Si) and/or silicon monoxide (SiO).

More specifically, an object of the present invention is to provide one (or more) improvement(s) to the apparatus according to US 11,267,714 to facilitate its use on an industrial scale for the production of a silicon-based material, such as silicon monoxide.

BRIEF DESCRIPTION OF THE INVENTION

• une chambre réactionnelle pour la mise en œuvre d’une réaction chimique à partir des réactifs, ladite chambre réactionnelle comportant :
  • une enceinte étanche raccordée à au moins une pompe d’aspiration pour générer une dépression à l’intérieur de l’enceinte lorsque la pompe d’aspiration est activée,
  • un four à arc électrique logé à l’intérieur de l’enceinte étanche pour chauffer les réactifs,
  • une cuve destinée à contenir les réactifs,
• une chambre de condensation pour solidifier un composé chimique contenu dans le gaz issu de la chambre réactionnelle, ladite chambre de condensation incluant :
  • un caisson de précipitation définissant un espace pour la solidification du composé chimique contenu dans le gaz issu de la chambre réactionnelle, ledit caisson de précipitation comportant au moins une cloison latérale,
  • un système de refroidissement pour refroidir le gaz issu de la chambre réactionnelle, ledit système de refroidissement étant en contact thermique avec la cloison latérale, et
  • une buse d’extraction pour la collecte du composé chimique solidifié, ladite buse d’extraction étant connectée au caisson de précipitation,
• une conduite d’acheminement pour la circulation du gaz entre la chambre réactionnelle et la chambre de condensation, ladite conduite d’acheminement étant raccordée à l’enceinte d’une part, et au caisson de précipitation d’autre part,

remarquable en ce que la chambre de condensation comprend en outre un vibrateur associé à la cloison latérale pour induire la génération de vibrations dans ladite cloison latérale.To this end, the invention provides an apparatus for producing a silicon-based material (such as silicon and/or silicon monoxide) from reactants, said reactants comprising quartz and at least one reducing agent wherein the apparatus comprises:

• a reaction chamber for carrying out a chemical reaction from the reactants, said reaction chamber comprising:
  • a sealed enclosure connected to at least one suction pump to generate a vacuum inside the enclosure when the suction pump is activated,
  • an electric arc furnace housed inside the sealed enclosure to heat the reagents,
  • a tank intended to contain the reagents,
• a condensation chamber for solidifying a chemical compound contained in the gas from the reaction chamber, said condensation chamber including:
  • a precipitation box defining a space for the solidification of the chemical compound contained in the gas from the reaction chamber, said precipitation box comprising at least one lateral partition,
  • a cooling system for cooling the gas from the reaction chamber, said cooling system being in thermal contact with the side partition, and
  • an extraction nozzle for collecting the solidified chemical compound, said extraction nozzle being connected to the precipitation box,
• a conveying pipe for the circulation of gas between the reaction chamber and the condensation chamber, said conveying pipe being connected to the enclosure on the one hand, and to the precipitation box on the other hand,

remarkable in that the condensation chamber further comprises a vibrator associated with the side partition to induce the generation of vibrations in said side partition.

As will become clear in the following, the presence of a vibrator to generate vibrations in the side wall makes it easier to detach the silicon-based material likely to be deposited on said side wall. This improves the efficiency of the apparatus according to the invention by limiting the risk of depositing a thick layer of material on the side wall, such a thick layer reducing the efficiency of the cooling of the gas from the reaction chamber, and therefore of the apparatus.

• la cloison latérale peut avoir une forme en tronc de cône, une génératrice de la cloison latérale formant un angle non nul avec un axe vertical ;
• le vibrateur peut être un vibrateur mécanique ;
• le vibrateur mécanique peut être configuré pour exercer un effort sur la cloison latérale selon un axe principal incliné d’un angle non nul par rapport à la cloison latérale, ledit angle non nul étant supérieur à 45° et inférieur à 135°, de préférence compris entre 60° et 120°, notamment de l’ordre de 90° ;
• le vibrateur mécanique peut s’étendre à l’extérieur de la cloison latérale, ledit vibrateur mécanique étant relié mécaniquement à la cloison latérale par un moyen de liaison mécanique, tel qu’une tige en contact d’une part avec la cloison latérale, et d’autre part avec le vibrateur mécanique ;
• le vibrateur peut être un vibrateur acoustique ;
• le vibrateur acoustique peut comprendre une pluralité de transducteurs disposés sur une face interne et/ou sur une face externe de la cloison, lesdits transducteurs ayant des fréquences de résonnance respectives ;
• la cloison latérale peut comprendre une couche de matériau antiadhérent telle qu’une couche de céramique, ou une couche de fluoropolymere, ou une couche d’oxydes métallique ;
• le système d’alimentation peut comprendre :
  • un bol de réception destiné à contenir une réserve de réactifs,
  • un canal de distribution pour la circulation des réactifs entre le bol de réception et la cuve, et
  • au moins deux valves pour autoriser ou stopper la circulation des réactifs entre le bol de réception et la cuve ;
• la buse d’extraction peut comprendre :
  • un entonnoir tronconique composé d’un muret latérale tronconique, un bord supérieur de plus grand diamètre du muret latéral tronconique étant raccordé à la cloison latérale, et
  • un tube monté sur un bord inférieur de plus petit diamètre du muret latéral tronconique,
  • au moins deux clapets pour autoriser ou interdire la circulation du matériau à base de silicium entre l’entonnoir tronconique et l’extérieur de la chambre de condensation.

Preferred but non-limiting aspects of the apparatus according to the invention are as follows:

• the side partition may have a truncated cone shape, a generator of the side partition forming a non-zero angle with a vertical axis;
• the vibrator can be a mechanical vibrator;
• the mechanical vibrator can be configured to exert a force on the side partition along a main axis inclined at a non-zero angle relative to the side partition, said non-zero angle being greater than 45° and less than 135°, preferably between 60° and 120°, in particular of the order of 90°;
• the mechanical vibrator may extend outside the side partition, said mechanical vibrator being mechanically connected to the side partition by a mechanical connecting means, such as a rod in contact on the one hand with the side partition, and on the other hand with the mechanical vibrator;
• the vibrator can be an acoustic vibrator;
• the acoustic vibrator may comprise a plurality of transducers arranged on an internal face and/or on an external face of the partition, said transducers having respective resonance frequencies;
• the side wall may comprise a layer of anti-adhesive material such as a ceramic layer, or a fluoropolymer layer, or a metal oxide layer;
• the power supply system may include:
  • a receiving bowl intended to contain a reserve of reagents,
  • a distribution channel for the circulation of reagents between the receiving bowl and the tank, and
  • at least two valves to allow or stop the circulation of reagents between the receiving bowl and the tank;
• the extraction nozzle may include:
  • a truncated funnel composed of a truncated side wall, a larger diameter upper edge of the truncated side wall being connected to the side partition, and
  • a tube mounted on a lower edge of smaller diameter of the truncated side wall,
  • at least two valves to allow or prevent the circulation of the silicon-based material between the truncated funnel and the outside of the condensation chamber.

• FIG. 1est une représentation schématique d’un appareil de production de silicium de l’art antérieur,
• FIG. 2est une représentation schématique d’un appareil de production de matériau à base de silicium selon l’invention,
• FIG. 3est une représentation schématique d’une chambre réactionnelle de l’appareil de production illustré à laFIG. 2,
• FIG. 4est une représentation schématique d’une chambre de condensation de l’appareil de production illustré à laFIG. 2.

Other advantages and characteristics of the apparatus and method for producing a silicon-based material according to the invention will emerge more clearly from the following description of several variant embodiments, given as non-limiting examples, from the attached drawings in which:

• FIG. 1 is a schematic representation of a prior art silicon production apparatus,
• FIG. 2 is a schematic representation of an apparatus for producing silicon-based material according to the invention,
• FIG. 3 is a schematic representation of a reaction chamber of the production apparatus illustrated in FIG. 2 ,
• FIG. 4 is a schematic representation of a condensation chamber of the production apparatus illustrated in FIG. 2 .

DETAILED DESCRIPTION OF THE INVENTION

We will now describe different examples of embodiments of the invention with reference to the figures.

1. General information

• une chambre réactionnelle 1,
• une chambre de condensation 2, et
• une conduite d’acheminement 3.

In reference to the FIG. 2 , the apparatus according to the invention comprises:

• a reaction chamber 1,
• a condensation chamber 2, and
• a delivery line 3.

• en présence d’agents réducteurs tels que du silicium, la chambre réactionnelle permet la formation de monoxyde de silicium gazeux,
• en présence d’agents réducteurs à base de carbone, la chambre réactionnelle permet la formation de silicium.

Reaction chamber 1 allows the implementation of the high-temperature quartz reduction reaction. Depending on the nature of the reducing agents, this reaction allows the formation of gaseous silicon monoxide and/or liquid silicon:

• in the presence of reducing agents such as silicon, the reaction chamber allows the formation of gaseous silicon monoxide,
• In the presence of carbon-based reducing agents, the reaction chamber allows the formation of silicon.

• pour la production de silicium, ou
• pour la production à la fois de silicium et de monoxyde de silicium solide.

In the following, the invention will be presented with reference to the production of silicon monoxide from quartz and a reducing agent such as silicon, it being understood that the invention can also be used:

• for the production of silicon, or
• for the production of both silicon and solid silicon monoxide.

Condensation chamber 2 cools the gases from reaction chamber 1.

Advantageously, the reaction chamber 1 and the condensation chamber 2 are distinct and separate, said chambers being connected via the conveying pipe 3. This makes it possible in particular to use reaction and condensation chambers 1, 2 of different shapes and dimensions. This also makes it possible to reduce the height of the apparatus.

The delivery pipe 3 allows the circulation of gases between the reaction chamber 1 and the condensation chamber 2. It may comprise one (or more) pipe(s) connected on the one hand to the reaction chamber 1, and on the other hand to the condensation chamber 2.

• de réduire les pertes thermiques lors du passage des gaz depuis la chambre réactionnelle 1 vers la chambre de condensation 2, et
• de limiter la condensation parasite de monoxyde de silicium sur la (ou les) face(s) interne(s) du (ou des) tuyau(x) de la conduite d’acheminement 3 (ce qui baisse le rendement matière de la réaction et peut provoquer un bouchage de la conduite 3).

In certain embodiments, the device may further comprise a thermally insulating structure associated with the conveying pipe 3. Such a thermally insulating structure allows:

• to reduce heat losses during the passage of gases from the reaction chamber 1 to the condensation chamber 2, and
• to limit parasitic condensation of silicon monoxide on the internal face(s) of the pipe(s) of the delivery line 3 (which reduces the material yield of the reaction and can cause blockage of the line 3).

Since such a thermally insulating structure is known to those skilled in the art, it will not be described in more detail below. This thermally insulating structure may, for example, be composed of a thick ceramic lining of aluminum oxide (alumina or silicon carbide) arranged around or inside the conveying pipe 3.

2. Reaction chamber

• d’une part de contenir les réactifs – à savoir le quartz et le (ou les) agent(s) réducteur(s) – utilisés pour la production du matériau à base de silicium, et
• d’autre part de chauffer à haute température lesdits réactifs pour induire la réaction de réduction chimique partielle du quartz afin d’obtenir le gaz contenant le matériau à base de silicium.

Reaction chamber 1 allows:

• on the one hand to contain the reagents – namely quartz and the reducing agent(s) – used for the production of the silicon-based material, and
• on the other hand, heating said reagents at high temperature to induce the partial chemical reduction reaction of quartz in order to obtain the gas containing the silicon-based material.

• un four à arc 11,
• un enceinte étanche 12,
• un système d’alimentation 13 en réactifs, et
• une cuve 14 destinée à contenir les réactifs,
• le four à arc 11 et la cuve 14 étant logés dans l’enceinte 12.

In reference to the FIG. 3 , reaction chamber 1 comprises:

• an arc furnace 11,
• a 12 waterproof enclosure,
• a reagent supply system 13, and
• a tank 14 intended to contain the reagents,
• the arc furnace 11 and the tank 14 being housed in the enclosure 12.

2.1. Arc furnace

The arc furnace 11 allows the reactants to be heated to a high temperature (in particular greater than or equal to 1200°C) to induce the chemical reduction reaction of the quartz in order to produce the gas containing silicon monoxide (II).

For the formation of an electric arc allowing the heating of the reactants (quartz and reducing agent), the arc furnace 11 comprises electrodes 111, 112 supplied either from a direct current source or from an alternating current source. Each electrode 111, 112 may consist of a cylindrical graphite bar extending vertically.

• une (ou plusieurs) électrode(s) mobile(s) 111 maintenue(s) par un (ou des) support(s) (non représenté(s)), la (ou chaque) électrode mobile 111 pouvant être introduite dans l’enceinte 12 en passant (chacune) par un orifice traversant ménagé dans l’enceinte 12,
• une (ou plusieurs) électrode(s) fixe(s) 112 logée(s) dans le fond de la cuve 14.

The arc furnace 11 may include:

• one (or more) mobile electrode(s) 111 held by one (or more) support(s) (not shown), the (or each) mobile electrode 111 being able to be introduced into the enclosure 12 by passing (each) through a through-orifice provided in the enclosure 12,
• one (or more) fixed electrode(s) 112 housed in the bottom of the tank 14.

The support(s) holding the movable electrode(s) 111 allow(s) the distance between the ends of the fixed and movable electrode(s) to be varied to control the quantity of energy transferred to the reagents contained in the tank 14.

As previously indicated, each electrode 111, 112 is connected to a direct current source or to an alternating current source. One of the advantages of a direct current supply is that the electrodes are not subject to the electromagnetic effects that the electrodes of a furnace supplied from an alternating current source undergo.

• la (ou les) électrode(s) mobile(s) 111 peut (peuvent) être raccordée(s) au pôle positif de la source de courant continu pour former anode,
• la (ou les) électrode(s) fixe(s) 112 peut (peuvent) être raccordée(s) au pôle négatif de la source de courant continu et former cathode.

In the case of a direct current power supply:

• the movable electrode(s) 111 can be connected to the positive pole of the direct current source to form an anode,
• the fixed electrode(s) 112 can be connected to the negative pole of the direct current source and form a cathode.

The arc furnace 11 being of a type known per se to those skilled in the art, its operation will not be described in more detail below.

2.2. Pregnant

The sealed enclosure 12 makes it possible to define an enclosed space in which it is possible to generate a depression or obtain an inert atmosphere, that is to say a space in which it is possible to reduce the pressure to a value lower than atmospheric pressure.

To reduce the pressure in the enclosure, the reaction chamber 1 comprises one (or more) suction pump(s) (not shown) connected to the enclosure 12 to generate a vacuum in the enclosure 12 by suction.

Reducing the pressure in enclosure 12 to a value below atmospheric pressure makes it possible to limit the temperature necessary to initiate the chemical reduction reaction of quartz.

Such an enclosure 12 may have different shapes and be made from different materials to perform this function. Thus, in the context of the present invention, the term “watertight enclosure” means a compartment composed of at least one wall 121 – for example made of steel – on either side of which there is a pressure difference. Thus, the watertight enclosure makes it possible to delimit two zones (i.e. an internal zone and an external zone) between which there is a pressure difference.

• d’un (ou de plusieurs) canal (canaux) d’injection de gaz 122, chaque canal 122 pouvant être connecté à une source d’alimentation en gaz (tel que de l’argon et l’azote),
• d’un (ou de plusieurs) canal (canaux) d’aspiration 123 pouvant être connecté à une pompe d’aspiration pour permettre la génération d’une dépression à l’intérieur de l’enceinte 11,
• d’un (ou plusieurs) canal (canaux) d’évacuation 124 destiné à être connecté à la conduite d’alimentation 3 pour le transfert du gaz issu de la chambre réactionnelle 1 vers la chambre de condensation 2,
• d’une (ou de plusieurs) des électrodes 111,
• de moyens de connexion électrique (tel qu’un câble électriquement conducteur, par exemple pour le raccordement électrique d’un capteur contenu dans l’enceinte, etc.),
• d’un canal (ou des canaux) de coulée 144, etc.

The sealed enclosure 12 comprises one (or more) through orifice(s), possibly for the passage of:

• of one (or more) gas injection channel(s) 122, each channel 122 being connectable to a gas supply source (such as argon and nitrogen),
• of one (or more) suction channel(s) 123 which can be connected to a suction pump to enable the generation of a vacuum inside the enclosure 11,
• of one (or more) evacuation channel(s) 124 intended to be connected to the supply pipe 3 for the transfer of the gas from the reaction chamber 1 to the condensation chamber 2,
• of one (or more) of the electrodes 111,
• electrical connection means (such as an electrically conductive cable, for example for the electrical connection of a sensor contained in the enclosure, etc.),
• of a casting channel (or channels) 144, etc.

The enclosure 12 is configured to withstand temperatures greater than or equal to 1000°C, in particular between 1200°C and 1800°C.

In some embodiments, the reaction chamber 1 may comprise a thermally insulating structure associated with the enclosure 12 to reduce heat losses in the housing. Such a thermally insulating structure may be composed of a thick ceramic lining of aluminum oxide (alumina or silicon carbide) arranged around or inside the enclosure 12.

2.3. Power supply system

The reagent supply system 13 makes it possible to fill the tank 14 with quartz and reducing agent(s).

• un bol de réception 131 destiné à contenir une réserve de quartz et d’agent(s) réducteur(s),
• un canal de distribution 132 pour la circulation du quartz et du (ou des) agent(s) réducteur(s), et
• deux (ou plus de deux) valves 133a, 133b étanches pour autoriser ou stopper la circulation du quartz et du (ou des) agent(s) réducteur(s).

The power supply system 13 includes:

• a receiving bowl 131 intended to contain a reserve of quartz and reducing agent(s),
• a distribution channel 132 for the circulation of quartz and the reducing agent(s), and
• two (or more than two) sealed valves 133a, 133b to allow or stop the circulation of quartz and the reducing agent(s).

The receiving bowl 131 comprises a bottom in which a through light is provided connected to one end of the distribution channel 132, the other end of the distribution channel 132 opening into the tank 14.

• chaque valve bloquant le passage des réactifs (quartz + agent(s) réducteur(s)) entre le bol de réception 131 et la cuve 14 dans l’état désactivé,
• chaque valve autorisant le passage des réactifs (quartz + agent(s) réducteur(s)) entre le bol de réception 131 et la cuve 14 dans l’état activé.

The two valves (hereinafter referred to as first and second valves) 133a, 133b are mounted on the distribution channel 132. A controller (not shown) makes it possible to control the valves from a deactivated state to an activated state (and from an activated state to a deactivated state):

• each valve blocking the passage of reagents (quartz + reducing agent(s)) between the receiving bowl 131 and the tank 14 in the deactivated state,
• each valve allowing the passage of reagents (quartz + reducing agent(s)) between the receiving bowl 131 and the tank 14 in the activated state.

The first and second valves 133a, 133b define a sealed compartment C between the receiving bowl 131 and the tank 14 (and more generally between the exterior and the interior of the enclosure 12).

To fill compartment C, the controller activates the first valve 133a and deactivates the second valve 133b. The reagents (quartz + reducing agent(s)) flow by gravity from the receiving bowl 131 to compartment C. When compartment C is filled with reagents, the controller deactivates the first valve 133a, then activates the second valve 133b. The reagents flow by gravity from compartment C to the tank 14. Once the compartment is emptied, the controller deactivates the second valve 133b and a new filling cycle can be initiated (activation of the first valve 133a for filling compartment C, etc.). The presence of two valves 133a, 133b makes it possible to maintain the enclosure 12 at a pressure lower than atmospheric pressure during the filling of the tank 14.

2.4. Tank

The tank 14 may consist of a graphite frame coated externally with a refractory lining. Alternatively, the tank 14 may be made of alumina, silica, metal or silicon carbide (SiC).

Tank 14 (or crucible) is intended to contain the reagents, but also the products and/or by-products resulting from the chemical reduction reaction of quartz.

The tank 14 has a bottom 141, one (or more) side wall(s) 142, and an upper opening 143. We note A-A’, a longitudinal central axis of the reaction chamber 1 which is vertical when the device is placed on a horizontal flat surface.

In the following, the description is oriented by considering that the terms "upper" and "high" correspond to a direction generally parallel to the axis A-A' and going from the bottom 141 towards the opening 143, while the terms "lower" and "lower" correspond to an opposite direction.

The bottom 141 of the tank 14 may comprise a stud projecting towards the inside of the tank 14. More precisely, the stud projects from the bottom 141 and extends along the axis A-A' towards the opening 143. The stud may be made of an electrically conductive material and constitute one of the electrodes of the arc furnace (typically the fixed electrode). Alternatively, the bottom 141 may be devoid of a stud and comprise only a circular recess through which one of the electrodes of the arc furnace is mounted. As a further variant, the bottom 141 of the tank 14 may be devoid of a stud and of a circular recess, in particular in the case where the electrode (or electrodes) of the arc furnace is (are) mounted above the tank 14.

The tank 14 also comprises a pouring channel (or several channels) 144 for discharging the reaction products and/or by-products contained in the tank 14 to an external pocket intended to receive it for subsequent storage. A closure system – such as a nozzle or a plug made of carbon material – may be provided for closing the pouring channel (or channels) at the end of the chemical reduction reaction of the quartz.

3. Condensation chamber

Condensation chamber 2 solidifies the silicon monoxide (II) contained in the gas from reaction chamber 1.

The condensation chamber 2 comprises a precipitation box 21, a cooling system 22, a vibrator 23 and an extraction nozzle 24.

3.1. Precipitation box

The precipitation box 21 may be cylindrical in shape. It comprises, for example, an upper partition 211, a side partition 212 and possibly a lower partition.

The upper partition 211 comprises a through orifice 213 connected to the conveying pipe 3 to allow the introduction – into the precipitation chamber 21 – of the gas from the reaction chamber 1.

Advantageously, the lateral partition 212 (or all the partitions) of the precipitation box 21 may comprise a layer of smooth non-stick material such as a ceramic layer, or a layer of metal oxides or a fluoropolymer layer. This makes it possible to promote/simplify the detachment of the solidified silicon monoxide deposited on the internal face of the lateral partition 212.

Furthermore, the lateral partition 212 of the precipitation box 21 may have a truncated cone shape. In particular, the generatrix of the lateral partition 212 may have a non-zero angle (in particular between 1 and 45°) with the vertical axis A-A’. This also makes it possible to promote/simplify the detachment of the solidified silicon monoxide deposited on the internal face of the lateral partition 212.

3.2. Cooling system

The condensation chamber 2 also comprises a cooling system 22 composed for example of one (or more) heat exchanger(s) in which a heat transfer fluid circulates.

The integration of a cooling system 22 makes it possible to rapidly cool the gas coming from the reaction chamber 1 in order to solidify the silicon monoxide (II) on the internal face of the side partition 212.

This rapid cooling of the gas limits the risks of restructuring, by disproportionation, of silicon monoxide (SiO) in the form of silicon (Si) and silicon dioxide (SiO ₂ ).

In the embodiment illustrated in the FIG. 4 , the cooling system 22 comprises a coil 221 surrounding the side partition 212 over its entire height. A heat transfer fluid 222 – such as water – circulates in the coil 221.

• d’une température de 1200°C à une température inférieure à 800°C lorsque l’appareil est utilisé à une pression inférieure à la pression atmosphérique, ou
• d’une température de 1600°C à une température inférieure à 800°C lorsque l’appareil est utilisé à la pression atmosphérique.

This allows the temperature of the gas containing silicon monoxide (II) to be reduced:

• from a temperature of 1200°C to a temperature below 800°C when the device is used at a pressure below atmospheric pressure, or
• from a temperature of 1600°C to a temperature below 800°C when the device is used at atmospheric pressure.

The cooling of the gas induces the solidification of the silicon monoxide contained therein. This solidified silicon monoxide is deposited on the internal face of the lateral partition 212 of the precipitation box 21.

3.3. Vibrator

In order to ensure the efficiency of the gas cooling, the condensation chamber 2 also comprises a vibrator 23 configured to generate vibrations on the surface of the side partition 212. The generation of vibrations makes it possible to detach the solidified silicon monoxide (II) deposited on the internal face of the side partition 212.

Thus, the presence of a vibrator 23 makes it possible to limit the thickness of the layer of silicon monoxide “d” deposited on the internal face of the precipitation box in order to ensure effective cooling of the gas contained in the condensation chamber 2: in fact, the deposition of too thick a layer of silicon monoxide on the internal face of the side partition would prevent the effective transfer of heat between the inside and the outside of the condensation chamber, which would prevent the rapid cooling of gas containing silicon monoxide (II).

The vibrator 23 may be of the acoustic type, that is to say a system converting electrical energy into acoustic energy, for example in the ultrasonic range.

Alternatively, the vibrator 23 may be of the mechanical type, that is to say a mechanical system generating vibrations using a rotary, linear or electromagnetic mechanism.

3.3.1. Acoustic vibrator

In the case of an acoustic vibrator, this comprises one (or more) transducer(s) and one (or more) generator(s) remote from the transducer(s) to supply the transducer(s) with electrical energy.

• d'une céramique réalisée à partir d'un matériau homogène ou piézocomposite
• et éventuellement d’un module de réglage (non représenté).

Each transducer is composed of:

• of a ceramic made from a homogeneous or piezocomposite material
• and possibly an adjustment module (not shown).

Each transducer constitutes a resonant element, like a tuning fork. The transducer(s) may be arranged on the internal face or (preferably on) the external face of the side partition 212.

In the embodiment illustrated in the FIG. 4 , the vibrator 23 comprises a plurality of transducers arranged on the external face of the side partition 212, and more precisely around the cooling system 22.

According to the invention, each transducer produces, in the lateral partition 212, waves with a frequency between 20 kHz and 5 MHz, preferably of the order of 100 kHz. This makes it possible to promote the detachment of the solidified silicon monoxide (II) deposited on the internal face of the lateral partition 212.

Advantageously, the waves are well distributed in the precipitation box 21 thanks to the fact that the transducers are placed homogeneously on the lateral partition 212. To obtain a homogeneous acoustic field, small transducers, i.e. less than 10 cm and preferably between 2 cm and 5 cm, can be used. This allows optimal paving. The shape of each transducer can, for example, be circular, square or polygonal.

Preferably, each transducer has its own resonant frequency. The fact that the natural frequencies of the transducers are different prevents standing waves from being established in the precipitation box 21. This has the advantage of improving the acoustic homogeneity in the precipitation box 21.

As mentioned earlier, each transducer may also include a tuning module, which may be a power electronics board. In this case, the transducer's piezoelectric ceramic is powered by the power electronics board, providing it with an alternating voltage corresponding to its own vibration mode.

3.3.2. Mechanical vibrator

In the case of a mechanical vibrator, this may include a core (or weight) mounted mobile in linear translation (along said main axis) on two aligned bearings, and driven by the action of a periodic and alternating electromagnetic field.

Such a mechanical vibrator is configured to exert an axial force (i.e. directed along a main axis (or direction)) on the lateral partition 212, this force being invariable over time.

Advantageously, the main axis along which the force is exerted may be inclined relative to the lateral partition 212 to be vibrated, by an angle greater than 45° and less than 135°, preferably between 60° and 120°, in particular close to 90°. This makes it possible to promote the detachment of the solidified silicon (II) monoxide deposited on the internal face of the lateral partition 212.

The mechanical vibrator can be arranged outside the precipitation box 21 and in particular around the cooling system 22 extending opposite the external face of the lateral partition 212. In this case, the mechanical vibrator is connected to the lateral partition 212 by a mechanical connection means, such as one (or more) rod(s) in contact on the one hand with the external face of the lateral partition 212, and on the other hand with the mechanical vibrator.

The use of an electromagnetic mechanical vibrator makes it possible to offer a vibration generation solution with a very low cost.

• ils sont compacts,
• ils sont de faible masse,
• ils sont robustes,
• ils permettent un fonctionnement en continu ; et
• ils sont capables d'appliquer au caisson de précipitation 21 – par l'intermédiaire du moyen de liaison mécanique – des efforts relativement importants, par exemple de l'ordre de quelques dizaines de newtons.

Such mechanical vibrators also have the following advantages:

• they are compact,
• they are of low mass,
• they are robust,
• they allow continuous operation; and
• they are capable of applying relatively significant forces to the precipitation box 21 – via the mechanical connection means – for example of the order of a few tens of newtons.

3.4. Extraction nozzle

The extraction nozzle 24 makes it possible to collect the silicon monoxide (II) powder detached from the side partition 212.

Advantageously, the extraction nozzle 24 can be positioned under the precipitation box 21 to recover the detached silicon monoxide (II) powder falling by gravity.

• un entonnoir 241 tronconique composé d’un muret latérale tronconique dont :
• le bord supérieur définit une base supérieure de grand diamètre fixée à la cloison latérale 212 (ou à la cloison inférieure si le caisson de précipitation 21 comprend une telle cloison inférieure), et
• le bord inférieur définit une base inférieure de plus petit diamètre, et
• un tube 242 monté au niveau de la base inférieure de l’entonnoir 241.

The extraction nozzle 24 includes:

• a truncated funnel 241 composed of a truncated side wall of which:
• the upper edge defines a large diameter upper base attached to the side partition 212 (or to the lower partition if the precipitation box 21 includes such a lower partition), and
• the lower edge defines a lower base of smaller diameter, and
• a tube 242 mounted at the lower base of the funnel 241.

The extraction nozzle 24 also comprises two (or more than two) sealed valves 243a, 243b to allow or stop the circulation of the solidified silicon monoxide (II) powder between the truncated funnel 241 and the outside of the condensation chamber 2. The valves 243a, 243b are mounted on the tube 242.

• chaque clapet 243a, 243b bloquant le passage de la poudre de monoxyde de silicium (II) entre l’entonnoir 241 et un récipient externe dans l’état désactivé,
• chaque clapet 243a, 243b autorisant le passage de la poudre de monoxyde de silicium (II) entre l’entonnoir 241 et le récipient externe dans l’état activé.

A controller (not shown) makes it possible to control the valves 243a, 243b from a deactivated state to an activated state (and from an activated state to a deactivated state):

• each valve 243a, 243b blocking the passage of the silicon monoxide (II) powder between the funnel 241 and an external container in the deactivated state,
• each valve 243a, 243b allowing the passage of the silicon monoxide (II) powder between the funnel 241 and the external container in the activated state.

The two valves 243a, 243b – hereinafter referred to as “first valve” and “second valves” – define a sealed compartment CE between the funnel 241 and the external container 5 (and more generally between the exterior and the interior of the condensation chamber 2).

To fill the CE compartment, the controller activates the first valve 243a and deactivates the second valve 243b. The silicon monoxide (II) powder flows by gravity from the funnel 241 to the CE compartment. When the CE compartment is filled with powder, the controller deactivates the first valve 243a, then activates the second valve 243b. The powder flows by gravity from the CE compartment to the external container 5. Once the CE compartment is emptied, the controller deactivates the second valve 243b and a new filling cycle can be initiated (activation of the first valve 243a for filling the CE compartment, etc.). The presence of two valves 243a, 243b makes it possible to maintain the precipitation box 21 at a pressure lower than atmospheric pressure during the filling of the external container.

4. Conclusions

• tel qu’une poudre de monoxyde de silicium (II), ou
• du silicium, ou
• du silicium et du monoxyde de silicium, ou
• un oxyde intermédiaire, SiOx (0<x<2).

The apparatus described above allows the continuous production of a silicon-based material:

• such as silicon(II) monoxide powder, or
• silicon, or
• silicon and silicon monoxide, or
• an intermediate oxide, SiOx (0<x<2).

The integration of a vibrator 23 makes it possible to detach the silicon monoxide (II) solidifying on the walls of the precipitation box 21 from the condensation chamber 2.

This limits the risks of disproportionation of silicon monoxide by ensuring rapid and efficient cooling of the gas generated in the reaction chamber.

The reader will understand that numerous modifications can be made to the invention described above without materially departing from the new teachings and advantages described herein.

Claims (10)

Apparatus for producing a silicon-based material from reactants, said reactants comprising quartz and at least one reducing agent wherein the apparatus comprises:

• a reaction chamber (1) for carrying out a chemical reaction from the reactants, said reaction chamber (1) comprising:
  • a sealed enclosure (121) connected to at least one suction pump to generate a vacuum inside the enclosure (121) when the suction pump is activated,
  • an electric arc furnace (11) housed inside the sealed enclosure (121) for heating the reactants,
  • a tank intended to contain the reagents,
• a condensation chamber (2) for solidifying a chemical compound contained in the gas coming from the reaction chamber (1), said condensation chamber (2) including:
  • a precipitation box (21) defining a space for the solidification of the chemical compound contained in the gas coming from the reaction chamber (1), said precipitation box (21) comprising at least one lateral partition (212),
  • a cooling system (22) for cooling the gas coming from the reaction chamber (1), said cooling system (22) being in thermal contact with the side partition (212), and
  • an extraction nozzle (24) for collecting the solidified chemical compound, said extraction nozzle being connected to the precipitation box (21),
• a conveying pipe (3) for the circulation of gas between the reaction chamber (1) and the condensation chamber (2), said conveying pipe (3) being connected to the enclosure (11) on the one hand, and to the precipitation box (21) on the other hand,

characterized in that the condensation chamber (2) further comprises a vibrator (23) associated with the side partition (212) to induce the generation of vibrations in said side partition (212). Apparatus according to claim 1, wherein the side partition (212) has a truncated cone shape, a generatrix of the side partition (212) forming a non-zero angle with a vertical axis (A-A'). Apparatus according to any one of claims 1 or 2, wherein the vibrator is a mechanical vibrator. Apparatus according to claim 3, wherein the mechanical vibrator is configured to exert a force on the lateral partition (212) along a main axis inclined at a non-zero angle relative to the lateral partition (212), said non-zero angle being greater than 45° and less than 135°, preferably between 60° and 120°, in particular of the order of 90°. Apparatus according to any one of claims 3 or 4, wherein the mechanical vibrator extends outside the side partition (212), said mechanical vibrator being mechanically connected to the side partition (212) by a mechanical connecting means, such as a rod in contact on the one hand with the side partition (212), and on the other hand with the mechanical vibrator. Apparatus according to any one of claims 1 or 2, wherein the vibrator is an acoustic vibrator. Apparatus according to claim 6, wherein the acoustic vibrator comprises a plurality of transducers arranged on an inner face and/or on an outer face of the side partition (212), said transducers having respective resonant frequencies. Apparatus according to any one of claims 1 to 7, wherein the side wall (212) comprises a layer of non-stick material such as a ceramic layer, or a fluoropolymer layer, or a metal oxide layer. Apparatus according to any one of claims 1 to 8, in which the power supply system (12) comprises:

• a receiving bowl (121) intended to contain a reserve of reagents,
• a distribution channel (122) for the circulation of reagents between the receiving bowl (121) and the tank (14), and
• at least two valves (123a, 123b) for authorizing or stopping the circulation of reagents between the receiving bowl (121) and the tank (14).

Apparatus according to any one of claims 1 to 9, wherein the extraction nozzle comprises:

• a truncated funnel composed of a truncated side wall, a larger diameter upper edge of the truncated side wall being connected to the side partition (212), and
• a tube mounted on a lower edge of smaller diameter of the truncated side wall,
• at least two valves to allow or prohibit the circulation of the silicon-based material between the truncated funnel and the exterior of the condensation chamber (2).