WO2007119605A1

WO2007119605A1 - Method and apparatus for producing silicon

Info

Publication number: WO2007119605A1
Application number: PCT/JP2007/057044
Authority: WO
Inventors: Susumu Sakaguchi
Original assignee: Shin-Etsu Chemical Co., Ltd.
Priority date: 2006-04-12
Filing date: 2007-03-30
Publication date: 2007-10-25
Also published as: JP2007284259A

Abstract

Disclosed is a method for producing silicon by reducing a chloride of silicon, which is characterized in that at least a metal is formed into liquid particles and the metal liquid particles are brought into contact with a gaseous chloride of silicon, thereby producing silicon through reduction of the chloride of silicon. Also disclosed is an apparatus for producing silicon, which is characterized by comprising at least a reaction chamber for reacting metal particles and a gaseous chloride of silicon, a means for heating the reaction chamber, a means for supplying the metal particles into the reaction chamber, a means for supplying the chloride of silicon into the reaction chamber, a means for discharging a fluid from the reaction chamber, and a container for collecting the produced silicon. Consequently, a low-cost silicon polycrystal for solar cells can be produced by such a method and apparatus.

Description

Specification

Silicon manufacturing method and manufacturing apparatus

Technical field

The present invention relates to a method and a manufacturing apparatus for manufacturing silicon, and more particularly to a method and a manufacturing apparatus for manufacturing silicon by reducing a chlorine compound of silicon with a metal.

Background art

[0002] In recent years, solar cells are rapidly spreading as clean energy sources.

Solar cells at the beginning of development were required to have higher performance by improving photoelectric conversion efficiency, but in recent years, as their use has increased, lower prices have been demanded.

[0003] Various compound semiconductors are used in addition to silicon as a material for power solar cells. Silicon is most often used from the viewpoints of power conversion efficiency, stability, safety, and abundance of resources. Yes. Conventionally, as raw materials for silicon, which is a material for solar cells, low-priced materials such as silicon single crystal exclusion products for electronic devices and single crystal silicon residual materials have been mainly used. However, along with the growth of solar cell factories, the shortage of supply of silicon raw material, which is the material of cells, has become a reality, and the solution is an urgent issue.

[0004] Currently, high-purity silicon single crystals for semiconductors are mainly produced from high-purity silicon polycrystals produced by the thermal decomposition method of trichlorosilane by the CZ method or FZ method.

[0005] Trichlorosilane is produced through at least three steps: (1) production of metallurgical metal silicon from silica (2) production of metallurgical metal silicon, and production of trichlorosilane (3) distillation purification of trichlorosilane. The

[0006] Currently, the mainstream thermal decomposition of trichlorosilane produces a large amount of silicon tetrachloride as a by-product, so that the resulting silicon polycrystal is expensive.

[0007] Therefore, since this high-purity silicon polycrystal is too expensive to be used for a solar cell, for example, a zinc reduction method of tetrasalt silicate silicon (for example, JP-A-11-92130). And the like. Refining method of metal silicon for metallurgy, hydrogen reduction method of trichlorosilane at high temperature (see Japanese Patent Laid-Open No. 2004-2138), etc. At present, sufficient results have not been obtained in terms of the quality and price of silicon polycrystals.

Disclosure of the invention

The present invention has been made in view of such problems, and an object thereof is to provide a method and an apparatus for producing a low-cost silicon polycrystal for a solar cell.

[0009] The present invention has been made in order to solve the above problems, and is a method for producing silicon by reducing a chlorine compound of silicon. There is provided a method for producing silicon, characterized in that silicon is produced by contacting particles with gaseous chlorine compound of silicon and reducing the chlorine compound of silicon.

[0010] In this way, if silicon is produced by bringing gaseous silicon chlorine compounds into contact with metal liquid particles to produce silicon, reduction can be performed with extremely high efficiency, or the present thermal decomposition of trichlorosilane. Since tetrasaltum silicon produced as a by-product in the process can be used as a raw material, the production cost of silicon polycrystal can be greatly reduced.

[0011] In this case, when the metal liquid particles are brought into contact with and reacted with the gaseous silicon chlorine compound, the gaseous silicon chlorine compound and the metal liquid particles are brought into contact in a countercurrent manner. Is preferred.

[0012] If the gaseous silicon chlorine compound and the metal liquid particles are brought into contact with each other in this manner, the reduction reaction by the metal of the silicon chlorine compound proceeds while the two are in contact with each other. Since the reaction efficiency can be increased, the manufacturing cost can be reduced by downsizing the apparatus.

[0013] In the silicon production method of the present invention, it is preferable that the metal liquid particles are floated when the metal liquid particles are brought into contact with and reacted with gaseous silicon chlorine compounds.

[0014] As described above, when the metal liquid particles are brought into a floating state when contacting and reacting the liquid metal particles with gaseous silicon chlorine compound, the metal reduction of the silicon chlorine compound is performed. Since the reaction proceeds in a floating state, the reaction proceeds very efficiently. In addition, it is possible to suppress unevenness in the progress of the reduction reaction due to the distribution of the metal liquid particles having a nonuniform particle size.

[0015] In the method for producing silicon of the present invention, it is preferable that the main component of the chlorine compound of silicon is silicon tetrachloride.

[0016] In this way, if the main component of the chlorine compound of the silicon to be reduced is tetrachlorosilane, by-products in the thermal decomposition method of trichlorosilane can be used as described above. Polycrystalline production costs can be reduced.

[0017] In the silicon production method of the present invention, it is preferable that the silicon tetrachloride is produced by allowing carbon and chlorine to act on silica stone.

[0018] In this way, if tetrasaltous silicon to be reduced is produced in one step by reacting carbon and chlorine with silica stone, the number of steps until the production of silicon polycrystals is the current one using trichlorosilane. Since it is less than the method, silicon can be manufactured at lower cost and cost.

[0019] Further, in the method for producing silicon of the present invention, the value of the free energy of formation per one atom of chlorine in the metal chloride as the liquid particle in the metal as the liquid particle is chlorine in the chlorine compound of silicon. It is preferable to use a metal that is lower than the value of free energy of formation per atom and that has a lower melting point than that of silicon.

[0020] In this way, the value of the free energy of formation per atom of chlorine in the metal chloride used as the liquid particle for reducing the metal chlorine compound to reduce the silicon chlorine compound. If the metal freezing energy is lower than the value of free energy of formation per chlorine atom and the melting point of the metal used as the liquid particles is lower than the melting point of silicon, the reduction reaction easily proceeds.

[0021] In the method for producing silicon of the present invention, it is preferable that the metal used as the liquid particles is either aluminum or zinc.

[0022] As described above, if the metal to be liquid particles for reducing the chlorine compound of silicon is either aluminum or zinc, the reduction reaction proceeds and it is inexpensive at once.

[0023] Further, in the method for producing silicon of the present invention, it is preferable that a particle diameter of the liquid metal particles is 20 to 200 zm. [0024] Thus, when the particle size of the metal liquid particles is 20 to 200 μm, the reduction reaction is completed in a short time and a sufficiently high reaction rate is obtained. In addition to being able to reduce the amount, it is possible to loosen the handling difficulties because the silicon produced is too fine.

In the silicon production method of the present invention, it is preferable that the temperature at which the metal liquid particles are brought into contact with and reacted with gaseous silicon chlorine compound is 800 ° C. or higher.

[0026] As described above, when the temperature at which the metal liquid particles are brought into contact with and reacted with gaseous silicon chlorine compound is 800 ° C or higher, the reduction reaction is completed in a short time, and a sufficiently high reaction rate is obtained. As a result, the amount of metal remaining in silicon can be reduced.

[0027] Further, in the silicon production method of the present invention, the pressure when the metal liquid particles are brought into contact with and reacted with gaseous silicon chlorine compound can be 1 atm or more.

[0028] As described above, when the pressure when the metal liquid particles are brought into contact with and reacted with gaseous silicon chlorine compound is 1 atm or more, the reduction reaction is completed in a short time, and a larger reaction rate is obtained. Therefore, it is possible to reduce the amount of metal remaining in the silicon and to reduce the size of the apparatus.

In the silicon production method of the present invention, the supply of the liquid metal particles and the supply of the chlorine compound of the silicon are intermittently performed to contact and react the liquid metal particles and the silicon chloride compound. Can be performed intermittently.

[0030] As described above, if the supply of the metal liquid particles and the supply of the chlorine compound of silicon are intermittently performed, and the contact and reaction between the metal liquid particles and the chlorine compound of silicon are intermittently performed, the reduction is achieved. Silicon generated by the reaction can be prevented from remaining in the reaction space. As a result, reaction efficiency can be improved.

In the silicon production method of the present invention, the metal can be converted into liquid particles by melting metal solid particles into metal liquid particles.

[0032] As described above, if the metal is made into liquid particles by melting the metal solid particles into metal liquid particles, silicon can be produced even using separately produced metal solid particles. It can be performed.

[0033] Further, in the method for producing silicon of the present invention, the metal is in the form of liquid particles. Alternatively, metal particles created by directing the central axis of a columnar metal vertically, heating and melting the lower end portion of the linear or columnar metal to flow down as a liquid metal, and spraying a fluid on the flowing liquid metal It is preferable to carry out by making liquid.

[0034] In this way, to convert the metal into liquid particles, the central axis of the linear or columnar metal is oriented in the vertical direction, and the lower end portion of the linear or columnar metal is heated and melted to flow as a liquid metal. The metal can be made into particles without bringing the metal melt into contact with the storage container by spraying a fluid onto the flowing liquid metal to form metal particles. For this reason, it is possible to reduce the contamination of silicon that is generated with less contamination of the metal from the container.

In this case, in the silicon production method of the present invention, it is preferable that the linear or columnar metal is melted by high frequency induction heating.

[0036] As described above, when the linear or columnar metal is heated and melted by high frequency induction heating, the surface layer portion of the metal can be effectively heated and melted in a non-contact manner, and the control of the molten state is efficiently performed. Can be implemented.

[0037] In the method for producing silicon of the present invention, it is preferable that the linear or columnar metal is heated and melted while rotating the linear or columnar metal around its central axis.

[0038] As described above, if the linear or columnar metal is heated and melted while rotating the linear or columnar metal around its central axis, the metal liquefaction in the outer surface layer of the linear or columnar metal is performed. The flow rate of liquid metal can be adjusted.

, The control becomes easier.

[0039] In the silicon production method of the present invention, it is preferable that the fluid to be sprayed is hydrogen, helium, argon or a mixture thereof.

Thus, if the fluid to be sprayed is any force of hydrogen, helium, argon, or a mixture thereof, particles can be formed without reacting with the liquid metal.

[0041] Further, in the method for producing silicon of the present invention, the fluid to be sprayed may contain the silicon chloride compound.

[0042] As described above, if the fluid to be sprayed contains a chlorine compound of silicon, a liquid metal is formed into particles, and at the same time, a reduction reaction between the metal liquid particles and the chlorine compound of silicon. The response can be advanced and it is efficient.

[0043] Further, the present invention is an apparatus for producing silicon, comprising at least a reaction vessel for reacting metal particles and gaseous silicon chlorine compound, means for heating the reaction vessel, and the reaction vessel Means for supplying the metal particles therein, means for supplying the chlorine compound of the silicon into the reaction vessel, means for discharging the fluid in the reaction vessel, and for collecting the produced silicon And a container for manufacturing silicon.

[0044] Thus, at least a reaction vessel for reacting metal particles and gaseous silicon chlorine compound, means for heating the reaction vessel, and means for supplying the metal particles into the reaction vessel A silicon production apparatus comprising: a means for supplying the chlorine compound of the silicon into the reaction container; a means for discharging the fluid in the reaction container; and a container for collecting the produced silicon. For example, a silicon manufacturing apparatus capable of manufacturing silicon at a lower cost can be provided.

[0045] In this case, it is preferable that the silicon production apparatus of the present invention includes means for suspending particles in the reaction in the reaction vessel.

[0046] Thus, if a means for suspending the particles in the reaction vessel is provided, the reaction can proceed with extremely high efficiency, and the particle size of the metal particles can be distributed without being constant. It can be set as the silicon | silicone manufacturing apparatus which can suppress the nonuniformity of the progress of the reduction reaction by having.

[0047] Further, in the silicon manufacturing apparatus of the present invention, the floating means has a funnel shape in which the horizontal cross-sectional area expands from the bottom to the top, and the chlorinated compound of silicon is It is preferable that the particles in the reaction space are suspended by supplying from the lower part of the suspension means.

[0048] Thus, the floating means has a funnel shape in which the horizontal cross-sectional area expands from the bottom to the top, and reacts by supplying a chlorine compound of silicon from the bottom of the floating means. As long as particles in the space are suspended, a silicon manufacturing apparatus having a flow velocity distribution in the floating means can be obtained. As a result, even if the metal particles have a particle size distribution, the particles can be suspended in a spatial position having an appropriate gas flow velocity. Thus, the silicon production apparatus can more appropriately suppress the progress of the reduction reaction.

[0049] In this case, in the silicon manufacturing apparatus of the present invention, the expansion ratio of the horizontal cross-sectional area of the floating means is set so as to correspond to the particle size distribution of the metal particles. Is preferred.

[0050] As described above, if the enlargement ratio of the horizontal sectional area of the floating means is set so as to correspond to the particle size distribution of the metal particles, the particle density in the reaction space of the floating means is equalized. Therefore, it can be set as the manufacturing apparatus which a reduction reaction advances more efficiently. As a result, even if the metal particles have a particle size distribution, it can be more appropriately controlled to float at a corresponding spatial position with an appropriate flow velocity, and the unevenness of the reduction reaction can be suppressed more appropriately. It can be set as the silicon manufacturing apparatus which can do.

[0051] In the silicon manufacturing apparatus of the present invention, it is preferable that the floating means has a structure in which a part of particles overflows.

[0052] Thus, if the floating means has a structure in which a part of particles in the reaction space overflows, it is possible to prevent silicon generated by the reduction reaction from continuing to stay in the reaction space. As a result, reaction efficiency can be improved.

[0053] In the silicon production apparatus of the present invention, it is preferable that at least the material of the reaction vessel is quartz.

Thus, if the material of the reaction vessel is quartz, contamination of the reaction vessel material force to the generated silicon can be minimized.

In the silicon production apparatus of the present invention, it is preferable that at least the inner wall of the reaction vessel is made of quartz or silicon.

[0056] As described above, even if at least the inner wall of the reaction vessel is made of quartz or silicon, contamination of the reaction vessel material force to the generated silicon can be minimized.

[0057] In the silicon production apparatus of the present invention, the means for supplying the silicon chlorine compound includes means for heating the reaction container with the silicon chlorine compound supplied to the reaction container in the reaction container. It is preferable that the heating is performed in advance.

[0058] Thus, the means for supplying the silicon chlorine compound is supplied to the reaction vessel. If the chlorine compound of silicon is heated in advance by a means for heating the reaction vessel, the reaction can proceed efficiently.

[0059] In the silicon production apparatus of the present invention, the means for controlling the amount of the metal particles to be supplied, the means for controlling the supply amount of the chlorine compound of the silicon, and the reaction in the reaction vessel It is preferable to provide means for controlling the temperature of the space, means for controlling the pressure in the reaction vessel, a deviation force, and one or more means.

[0060] Thus, the means for controlling the amount of metal particles to be supplied, the means for controlling the supply amount of the chlorinated silicon compound, the means for controlling the temperature of the reaction space in the reaction vessel, Any device that controls the pressure in the reaction vessel, any silicon manufacturing device equipped with one or more means can control the reaction more stably and efficiently. .

[0061] Further, the silicon production apparatus of the present invention preferably includes a means for collecting by-products in the reaction.

[0062] As described above, the silicon production apparatus provided with a means for collecting the by-product in the reaction is preferable in terms of the environment, and the by-product in the reaction can be reused. May be able to produce silicon.

[0063] Further, the silicon production apparatus of the present invention preferably includes at least one of means for collecting unreacted silicon chlorinated compounds and means for circulating use.

[0064] In this manner, if the silicon production apparatus includes at least one of means for collecting unreacted silicon chlorine compounds and means for circulating use, unreacted silicon chlorine compounds are recycled. It can be used and silicon can be manufactured at a lower cost.

[0065] In the silicon production apparatus of the present invention, it is preferable that the container for collecting the generated silicon includes a means for heating the silicon collected in the container.

[0066] As described above, if the container for collecting the generated silicon is provided with a means for heating the silicon, the reaction can be completed more reliably by heating the generated silicon, and the by-product can be obtained. And the condensation of unreacted silicon chlorine compounds [0067] In this case, in the silicon production apparatus of the present invention, the means for heating the silicon collected in the container melts and collects the collected silicon from one direction. Is preferred.

[0068] As described above, if the means for heating the silicon collected in the container is an apparatus for producing silicon that melts the collected silicon and solidifies it in one direction, the granular silicon is transformed into silicon. Can be ingot-shaped. In addition, the purity of silicon can be improved.

[0069] In the silicon production apparatus of the present invention, it is preferable that the container for collecting the generated silicon is provided with means for supplying a chlorine compound of silicon.

[0070] As described above, if the container for collecting the produced silicon is provided with means for supplying the chlorine compound of silicon, the reaction can be completed more reliably.

[0071] The present invention also provides a method for producing silicon, characterized in that silicon is produced by reacting metal liquid particles with a silicon chloride compound using the above-described silicon production apparatus.

[0072] Thus, if silicon is produced by reacting metal liquid particles with a chlorine compound of silicon using any one of the above-described silicon production apparatuses, the ability to produce silicon at a lower cost. S can.

In this case, in the method for producing silicon of the present invention, the supply of the metal particles and the supply of the chlorine compound of the silicon to the reaction vessel are intermittently performed, and the liquid particles of the metal and the chlorine compound of the silicon are supplied. It is preferable to perform this reaction intermittently.

[0074] Thus, using the above-described silicon production apparatus, the supply of metal particles and the supply of silicon chlorine compound to the reaction vessel are intermittently performed, and the metal liquid particles and silicon chlorine compound are supplied. If this reaction is performed intermittently, it is possible to prevent silicon produced by the reduction reaction from remaining in the reaction space. As a result, reaction efficiency can be improved.

[0075] Further, it is preferable that the gaseous silicon chlorine compound and the liquid particles of the metal are contacted and reacted in a countercurrent manner.

[0076] Thus, using the above-described silicon manufacturing apparatus, gaseous silicon chlorine compound and gold If the liquid particles of the genus are contacted and reacted in a countercurrent state, the reduction reaction by the metal of the silicon chlorinated compound proceeds while they are in contact with each other, so the reaction efficiency per reaction space can be increased. The manufacturing cost can be reduced by downsizing the apparatus.

[0077] Further, it is preferable that the particles in the reaction are in a suspended state.

[0078] In this way, if the particles during the reaction are made to be in a floating state using the above-described silicon production apparatus, the reduction reaction of the silicon chlorinated compound with the metal proceeds in a floating state. In addition to allowing the reaction to proceed efficiently, it is possible to suppress unevenness in the progress of the reduction reaction due to the distribution of the liquid particle size of the metal being not constant.

[0079] As described above, according to the present invention, a silicon material used as a raw material for a solar cell or the like can be manufactured at a lower cost than conventional methods. Brief Description of Drawings

FIG. 1 is a schematic cross-sectional view showing an example of a silicon production apparatus of the present invention.

FIG. 2 is a schematic cross-sectional view showing another example of the silicon production apparatus of the present invention.

FIG. 3 is a schematic sectional view showing still another example of the silicon manufacturing apparatus of the present invention.

FIG. 4 is a schematic sectional view showing still another example of the silicon production apparatus of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

[0081] Hereinafter, the present invention will be described in more detail. The present invention is not limited to this.

As described above, there has been a problem in that a method for producing silicon, which is a material for solar cells, is low in cost and has been established in large quantities.

[0082] Therefore, the present inventors have developed the above-described zinc reduction method of silicon tetrachloride and the aluminum reduction method of silicon tetrachloride, which has not been industrially studied at all, to produce a high-purity reducing metal. The present invention has been completed by considering that the reaction rate can be greatly increased by increasing the surface area of contact with tetrasilicate silicon in the form of particles and making them liquid.

That is, in the present invention, at least metal is made into liquid particles, brought into contact with gaseous silicon chlorine compound, and silicon is generated by reducing the silicon chlorine compound. The present invention relates to a silicon manufacturing method and a manufacturing apparatus capable of manufacturing silicon by such a method.

When metal and gaseous silicon chlorinated compounds come into contact and react, the chlorinated silicon compounds are reduced to produce metallic chlorinated compounds and silicon. At this time, if the metal is liquid, a reaction with a high reaction rate can be performed efficiently. Furthermore, if the metal is a liquid particle, the surface area of the metal can be increased, and the reaction can proceed more efficiently.

By this reaction, the silicon chlorine compound reacted with the metal liquid particles is reduced to silicon. On the other hand, the metal chlorine compound as a by-product is removed as a gas.

[0084] In this case, it is preferable to react the metal particles and the chlorine compound of silicon in a countercurrent state. In particular, the reduction reaction is performed while the particles settle in the gaseous chlorine compound of the gas flowing upward in the reaction space. It is preferable that the process proceeds. As a result, the reaction can be completed within a relatively short reaction space in the vertical direction, so that the volume of the apparatus can be made smaller and economically configured.

[0085] Thus, according to the present invention, the conventional pyrolysis method of trichlorosilane, which is the central manufacturing method of silicon polycrystals for semiconductors, that is, the production of metal silicon for metallurgy from quartzite, for metallurgy. Production of chlorinated silicon compounds (mainly trichlorosilane) from metallic silicon. Distillation purification of trichlorosilane. Compared to the production method of polycrystalline silicon by thermal decomposition (including partial hydrogen reduction) of trichlorosilane. Silicon tetrachloride, a by-product of the pyrolysis method of chlorosilane, can be effectively used (2), or silicon polychloride produced directly from silica can be used to reduce the number of processes, thereby reducing silicon polycrystals at a lower cost. Can be manufactured.

[0086] In the following, an example of an embodiment is shown to the extent that the silicon manufacturing apparatus of the present invention is described in detail with reference to the drawings, and is limited to this as long as the technical idea of the present invention is used. It is not something.

As schematically shown in FIG. 1, the silicon production apparatus according to the present invention is roughly divided into a metal particle supply means 3 and a silicon chlorine compound that is reduced by liquid metal particles. Reaction region 1 that produces The reaction region 1 mainly includes a reaction vessel 12, a floating means 13 disposed in the reaction vessel 12, a heating means 14 for heating and holding the reaction vessel 12 at a predetermined temperature, and silicon in the reaction vessel 12. Means for supplying chlorine compounds 15 and gaseous reaction in reaction vessel 12 Means for discharging gases such as by-products and unreacted silicon chlorine compounds (mainly silicon tetrachloride) 17 and means for collecting by-products 20, an unreacted material collecting means 21, and a silicon container 10. The reaction vessel 12 is connected to the metal particle supplying means 3 at the upper end.

[0088] Of these, the metal particle supply means 3 is preferably a metal liquid particle supply means capable of controlling the particle size while preventing the metal from being contaminated as much as possible. It is preferable to use the high frequency induction heating configured as described above. In other words, a linear or columnar metal 31, a holder 32 and a holding shaft 29 that hold the linear or columnar metal 31 on the upper portion thereof via a heat insulating material 30, and a diagram in which the holding shaft 29 is driven to rotate up and down. Non-driving means, a container 33 that contains the entire linear or columnar metal, a high-frequency induction heating coil 35 that heats and melts the lower part of the linear or columnar metal, and a high-frequency induction heating coil 35 that is linearly or A shielding material 36 made of, for example, quartz to prevent contact with the columnar metal 31 and one or more particles of the liquid metal in a normal manner by spraying the fluid 39 toward the free-falling liquid metal stream 37 The nozzle 38 and force are configured. In addition, when the linear or columnar metal 31 is rotated around its central axis, a tilt mechanism 40 is preferably provided as means for adjusting the deviation of the central axis from the rotational axis. In addition, a melting zone 34 is formed below the linear or columnar metal at a predetermined distance from the high frequency induction heating coil 35.

That is, the outer diameter of the linear or columnar metal 31 gradually decreases from the end toward the lower end over a predetermined length from the end, for example, as shown in the longitudinal section in the figure. The melting zone 34 is present. The metal surface layer heated by high-frequency induction heating melts and flows downward, and falls freely from the bottom end. This flow rate (volume flow rate or weight flow rate) is determined by the shape of the melting zone 34, the high frequency induction heating power, the descending speed of the linear or columnar metal 31, etc. Adjusted to quantitative. An example of the cross-sectional shape of the melting zone 34 is shown in the figure, What is necessary is just to set an optimal shape by the characteristic and melting amount of a metal material.

Note that the shielding material 36 is not necessarily provided when contamination from the coil material is not particularly problematic.

[0090] It is preferable to include means for rotating the linear or columnar metal around its central axis. With such a manufacturing apparatus, the metal liquefaction in the outer surface layer of the linear or columnar metal can be equalized over the outer periphery, so that the flow amount of the liquid metal can be easily adjusted and controlled.

In the silicon production apparatus of the present invention as described above, the liquid metal particles are supplied into the reaction vessel 12 from the top and the chlorine compound of silicon is supplied from the bottom, and the inside of the reaction vessel 12 is appropriately heated by the heating means 14. If the temperature is reached, a reaction in which the chlorine compound of silicon is reduced by the metal proceeds, and the generated silicon is accommodated in the silicon container 10.

For the structure and configuration of the reaction vessel 12, conventional techniques relating to a moving bed powder reactor can be referred to.

Further, the heating device 14 can be appropriately selected as a medium power of a normal heating device such as high-frequency heating, lamp heating, resistance heating or the like.

[0092] It is preferable that the floating means 13 is appropriately arranged in the reaction vessel 12 by a holding means 23 such as a spoke-like holding means that disturbs the motion state of gas and particles as much as possible. In addition, as shown in FIG. 1, the floating means 13 preferably has a funnel shape whose horizontal cross-sectional area expands from the bottom to the top. With such a shape, particles can be suspended in an appropriate state by supplying a chlorine compound of silicon from the lower part of the suspension means. When such a floating means 13 is arranged in the reaction vessel 12, the linear velocity of the reaction gas supplied from the lower part of the floating means 13 becomes slower near the upper part, which is faster near the lower part of the floating means 13. Therefore, particles with a large particle size float near the lower part of the floating means 13, and float at a higher part as the particle size decreases. Therefore, even if the metal particles have a particle size distribution, the reaction can proceed efficiently with all particles.

[0093] Further, the expansion ratio of the cross-sectional area in the horizontal direction of the floating means at this time is appropriately set according to the particle size distribution of the particles, more preferably the radius (z) of the floating means with respect to the height direction (z) ( R) If the rate of change (dR / dz) is set in a fixed correspondence to the rate of change (dw / dr) of the cumulative weight distribution rate (w) of the metal particles to the particle size (r), Even if the particles have a particle size distribution, the volume density of the particles in the reaction space can be equalized.

[0094] Further, the floating means 13 may be provided with a structure in which a part of the floating particles is appropriately overflowed. For example, as shown in FIG. 1, an overflow hole is appropriately provided in the conical portion of the funnel-shaped floating means 13, or a gap is formed between the inner wall of the reaction vessel 12 and the floating means 13. In the case of the silicon manufacturing apparatus having such a structure, a part of the particles fall into the reaction container 12 from the overflow holes and the gaps and are stored in the silicon container 10, so that silicon can be continuously manufactured. Power S can be. When silicon is produced using this apparatus, the above-described method of intermittently performing the reduction reaction may be used in combination. That is, the supply of silicon from the chlorine compound supply means 15 and the supply of metal particles from the supply means 3 to the reaction vessel are intermittently performed.

[0095] The reaction vessel 12 and the floating means 13 can be selected from ordinary materials. Preferably, quartz, more preferably synthetic quartz having a high purity, is used to minimize contamination of silicon. It is desirable that at least the inner walls of the reaction vessel 12 and the floating means 13 are designed to be quartz or high-purity silicon. In this case, transparent quartz is preferable from the viewpoint of heating efficiency.

[0096] When the chlorine compound of silicon is supplied into the reaction vessel 12 at a temperature that is significantly lower than the temperature in the reaction space, temperature distribution may occur in the reaction space, and the progress of the reduction reaction is uneven. Since there is a possibility of connection, the chlorine compound of silicon is preferably preheated.

Further, as shown in FIG. 1, the means 15 for supplying the silicon chlorinated compound may have a supply pipe having a spiral structure in the reaction vessel. If it is a means for supplying silicon chlorine compound having such a supply pipe, the silicon chlorine compound supplied to the reaction vessel is preheated by means 14 for heating the reaction vessel. be able to. In this way, it is possible to more efficiently preheat the silicon chlorine compound supplied to the floating means.

In addition, the silicon production apparatus of the present invention preferably includes means 20 for collecting by-products in the reaction. In this way, by-products in the reaction (aluminum salt Etc.) can be collected effectively. In addition, it is preferable to provide at least one of means 21 for collecting unreacted silicon chlorinated compounds 21 and means for recycling. As a result, the chlorine compound of unreacted silicon can be recovered and reused or recycled, so that a silicon production apparatus that can produce silicon at a lower cost can be obtained.

[0098] A heating device 18 is disposed outside the silicon receiver in order to prevent unreacted silicon chlorine compounds and by-product metal chlorides from condensing inside the silicon receiver.

Further, if the temperature in the silicon container 10 is heated to a temperature equal to or higher than the melting point of silicon by the heating device 18, the collected silicon is melted in the silicon container 10. If the molten silicon is gradually solidified in one direction from the bottom to the top, impurities that have a segregation coefficient of less than 1 in the cooling process are concentrated upward due to the segregation phenomenon. The purity of the silicon portion is improved accordingly.

[0099] The silicon container 10 may be provided with means 16 for supplying a chlorine compound of silicon.

Thereby, even if the metal remains unreacted in the particles in the silicon receiver, it can be completely reacted. The silicon collected in the silicon container 10 according to the present invention, particularly when it is reduced by liquid particles of aluminum, may leave unreacted force metal that has almost completed the reaction. Therefore, the reaction can be completed more reliably by supplying the silicon chlorine compound to the silicon container 10 and heating the generated silicon.

Further, the silicon container 10 may be provided with a fluid outlet.

[0100] In addition, in order to carry out the reaction accurately and stably, means for controlling the entire apparatus can be appropriately added to the silicon manufacturing apparatus of FIG. That is, means for controlling the particle size and amount of the liquid metal particles to be supplied, means for controlling the supply amount of the chlorine compound of silicon, means for controlling the temperature of the reaction space in the reaction vessel, pressure in the reaction vessel It is a means to control.

[0101] For example, means for controlling the particle size and amount of the liquid metal particles supplied include, for example, the power of the high-frequency induction heating coil 35, the descending speed of the linear or columnar metal 31, and the gas discharged from the nozzle 38. The flow rate or pressure may be controlled. Chlorination of silicon For example, the valve 19 can control the supply amount of the compound. As a means for controlling the temperature of the reaction space in the reaction vessel, the power supplied to the heating means 14 is controlled. The pressure in the reaction vessel can be controlled by a known technique using the pressure gauge 22 or the like.

[0102] Another example of the apparatus of the present invention is schematically shown in FIG. The part 5 in the figure shows the means for supplying metal particles. The metal particles 51 are supplied from the hopper 52 through, for example, the valve 54 and the supply pipe 53, and at the upper part of the reaction vessel 65, the metal particles 51 are supplied from the metal particle supply port to the reaction space 66 at a predetermined supply rate (volume supply amount or weight supply per time Amount). The particles in the hopper 52 are preheated to a temperature as high as possible within a range in which metal particles are not bonded to each other by appropriately providing heating means. Although FIG. 2 illustrates the external heating device 50, a heating means may be provided inside the hopper. The metal particles are kept at a high temperature by the second heating means 57 even when passing through the supply pipe 53.

[0103] The portion 6 in the figure is a region where metal particles react with a chlorine compound of silicon. The reaction vessel 65 is heated by an external heating means 68 so that the reaction space 66 is maintained at a predetermined reaction temperature. While falling inside the reaction vessel 65, the metal particles are heated and heated by the heating means 68 and melted into liquid particles. The chlorine compound of silicon is supplied in gaseous form from the silicon compound supply means 69 at the lower end of the reaction vessel 65 at a predetermined weight supply rate (weight supply amount per hour), and flows upward in the reaction vessel 65. While passing, it contacts the falling metal particles in countercurrent and reacts with the metal, which leads to the reduction of silicon to chlorinated compounds. By-products such as aluminum chloride (mainly aluminum chloride) generated during the reaction with unreacted silicon chlorine compounds are discharged from the outlet 70 at the top of the reaction vessel. The discharged gaseous mixture of silicon chloride and aluminum salt is passed through a collection vessel (not shown) to condense and remove the aluminum chloride, and the silicon chlorine compound can be recycled to the reaction vessel again. Alternatively, it may be condensed in a second collection container and recovered in liquid form.

[0104] The falling speed of the particles in the reaction space is mainly determined by the diameter of the particles, the temperature, pressure and density of the gas, the viscosity of the gas determined by them, the linear velocity of the upward flow of the gas, etc. The larger the particle size, the faster the falling speed. The particle size of the metal particles used is Therefore, all particles do not fall at a uniform speed, so the residence time of particles in the reaction space depends on the particle size. Time is shortened. Therefore, when using a cylindrical reactor with a uniform diameter as shown in Fig. 2, the particle size distribution of metal particles, gas density and viscosity under operating conditions, linear velocity in the reaction vessel, etc. In consideration of the above, the inner diameter and height of the reaction vessel should be optimally designed so that the metal particles with the largest diameter can sufficiently react within the range where generated silicon is not discharged from the discharge port 70 at the top of the reaction vessel. .

[0105] When the height of the reaction vessel becomes excessive, the reaction vessel is divided as shown in Fig. 2 (two divisions are illustrated in Fig. 2), and a classifier 74 is placed between each reaction vessel. Install and classify into fine and coarse particles. Fine particles are taken out from the fine particle outlet 72 and collected in a fine particle collector (not shown). The coarse particles are supplied to the second reaction vessel 85 through the valve 75 and the coarse particle supply pipe 73, for example, and further reacted with the silicon chlorine compound. Similarly to the first reaction vessel, silicon chlorine compound is supplied in gaseous form from the silicon chlorine compound supply means 89 to the second reaction vessel, and the reaction space 86 is brought to a predetermined temperature by the external heating means 88. Adjusted to control. The diameter and height of the second reaction vessel are set by the same procedure as that for the first reaction vessel as long as coarse particles are not discharged from the gas outlet 80. The coarse silicon particles 95 after the reaction are accommodated in a collection container 94. In FIG. 2, a cyclone type classifier is illustrated as a classifier, but other classifiers may be used. The diameter of the second reaction vessel 85 is made smaller than that of the first reaction vessel 65 for the purpose of increasing the linear velocity of the chlorine compound of silicon in order to reduce the sedimentation rate of the coarse particles.

[0106] For example, by using the silicon manufacturing apparatus shown in Fig. 1 or Fig. 2, the silicon manufacturing method of the present invention, that is, a method of manufacturing silicon by reducing a chlorine compound of silicon, At least, a silicon production method is characterized in that silicon is produced by forming metal by making the metal liquid particles, bringing the metal liquid particles into contact with gaseous silicon chlorine compound, and reducing the silicon chlorine compound. can do. An example is shown below.

[0107] In general, powders, not limited to metals, have a particle size distribution. In this way, if the particle size is not constant and distributed, the progress of the reduction reaction varies depending on the liquid particles of each metal. , Some can leave the reaction incomplete. In other words, the high-concentration metal remains in the generated silicon, and the quality deteriorates.

Therefore, in the present invention, it is preferable to reduce the particles while maintaining the floating state using the floating means 13 or the like as shown in FIG. As a result, the reduction reaction can proceed effectively even if the particle size of the particles is not constant and has a distribution. Moreover, in the floating state, the contact of gaseous silicon with the chlorinated compound is promoted, and it is possible to accelerate the reaction so efficiently. Alternatively, the reaction tower may be divided into a plurality of stages as shown in FIG.

[0108] The chlorine compound of silicon used in the present invention can be mainly tetrasalt-silicon. The silicon chlorine compound used in the present invention is synthesized by directly synthesizing a silicon chlorine compound from silica using, for example, a method in which silica and carbon are reacted in one step with silica and purified by a method such as distillation. Can be used. The main component of the silicon chlorinated compound obtained by this method is tetrasaltary silicon. In this way, the silicon production method that produces silicon by reducing the chlorine compound of silicon produced in one step from quartzite with metal is more effective than the conventional method for producing silicon by pyrolysis of trichlorosilane. It can be set as the manufacturing method of silicon with few. In order to synthesize silicon chlorine compounds (mainly silicon tetrachloride) directly from silica stone in one step, a known technique such as disclosed in German Patent No. 1079015 or British Patent No. 865939 is used. It can be used as appropriate. In addition, a well-known distillation purification technique for trichlorosilane for producing semiconductor silicon can be applied to the distillation of chlorine compounds of silicon (mainly silicon tetrachloride).

Further, in the method of the present invention, tetrasalt silicon silicon produced as a by-product when producing silicon for semiconductor from trichlorosilane can also be utilized.

[0109] In principle, the metal used in the present invention has a value of free energy of formation per chlorine atom lower than the value of free free energy of formation of chlorine compound of silicon and its melting point is higher than that of silicon. Low metals can be used. Further, it is preferable that the metal has a low solubility in silicon and can easily separate a generated metal salt from silicon. Such metals can be easily removed even if they remain in silicon. The Furthermore, it is desirable that the metal be commercially available at a relatively low cost. Examples of such a metal include aluminum and zinc. When these metals are used, the free energy change value (AF) of the reaction and the equilibrium constant (K) of the reaction in the temperature range of 1200 ° C (1473 ° K) from 700 ° C (973 ° K) force Table 1 (Zinc is 1 atm, 1000 ° C

P

Since the above is a gas, the value at a temperature of 1000 ° C. or higher is not shown), and the reduction of the chlorine compound of silicon proceeds immediately, and it is particularly preferable to use aluminum.

Aluminum is also useful in that a material with a purity of 99.99% or more can be obtained as a columnar billet at a relatively low cost.

[table 1]

[0111] In the method for producing silicon according to the present invention, as described above, by adjusting the flow rate and pressure of the gas supplied from the nozzle 38 and the metal flow 37, the particle size of the liquid metal particles is set to 20 to 200 µm. It is preferable to control so that it becomes. If the particle size of the metal liquid particles is smaller than 20 zm, the particle size of the silicon particles produced after the reduction reaction becomes too small. If the particle size of the generated silicon particles is too small, special handling is required, and the surface area is increased, so that impurities and the like are easily adsorbed and the quality is likely to deteriorate. On the other hand, if the particle size of the metal liquid particles is larger than 200 μm, it takes longer for the entire metal particle to finish reacting with the chlorine compound of silicon, or it is excessive to float the particle. Therefore, it is not always suitable for the reaction to proceed properly.

[0112] In order to make a metal into a liquid state, it is necessary to heat it to a melting point or higher of the metal, and it is desirable that the temperature of the reaction space should be at least 100 ° C higher than the melting point by using the heating means 14. Since the metal is supplied to the reaction space in the form of liquid particles, the reaction is relatively fast. Proceeds quickly. Metal particles are converted to silicon by reaction. In order to speed up this conversion and reduce the metal for reduction remaining in the silicon or the impurity component in the metal, it is better to set the reaction space temperature to 800 ° C or higher. However, since the boiling point of the liquid is 998 ° C under the pressure of 1 atm, it is necessary to set the temperature lower than the boiling point in the pressure value of the reaction space as the reaction temperature. Silicon produced by the reaction between gaseous zinc and silicon chlorinated compounds is extremely fine, so it is not always desirable to take into account subsequent handling, etc.

[0113] The pressure of the gas phase during the reduction reaction should be adjusted and controlled to atmospheric pressure, preferably 1 atmospheric pressure, but is not necessarily limited thereto. It may be set to a pressure higher than 1 atm, for example 1 to 10 atm. As a result, the reaction can be carried out in a smaller reaction space, so that the productivity of the apparatus can be increased.

[0114] In order to prevent the silicon produced by the reduction reaction from remaining in the reaction space when the metal liquid particles react with the silicon chlorine compound, the supply of the metal liquid particles and the silicon chlorine compound are prevented. May be intermittently performed to contact the liquid metal particles with the chlorine compound of silicon intermittently.

[0115] For example, the following method can be employed as a method for forming metal into particles. That is, as shown in FIG. 1, the central axis of the linear or columnar metal is oriented vertically, and the lower end portion of the linear or columnar metal is heated and melted by the high frequency induction heating coil 35 to flow down as a liquid metal. In this method, a fluid is sprayed from the nozzle 38 onto the flowing liquid metal to form liquid metal particles. According to such a method, as in the conventional metal particle production method used for powder metallurgy and the like, since a container for holding a molten metal is not used, liquid metal particles can be formed in a non-contact manner. Since powerful contamination can be prevented, contamination of the silicon produced can be reduced.

[0116] In the present invention, it is preferable that the metal is melted by high-frequency heating as described above. By using high-frequency heating, the surface layer of the metal can be effectively heated and melted, the control of the molten state can be carried out efficiently, and since it is non-contact, there is little contamination.

[0117] In this case, it is preferable to rotate the linear or columnar metal around its central axis. That is, as described above, by rotating the holder 32, the linear or columnar metal is rotated around its central axis, and the molten metal liquefaction on the outer surface layer of the linear or columnar metal is equalized over the outer periphery. This makes it easy to adjust and control the flow rate of the liquid metal.

In addition, when rotating a linear or columnar metal, depending on the degree of straightness of the metal, it is actually difficult to rotate so that the central axis is completely more or less stationary. It is preferable to provide an adjusting means for minimizing the deviation (regularity, loose runout) of the center axis of the columnar metal or the columnar metal with respect to the rotation center axis. This makes it possible to further stabilize the formation of liquid metal particles.

[0118] At this time, the fluid sprayed from the nozzle 38 toward the liquid metal stream 37 that flows down is a gas, preferably hydrogen, helium, argon, or a mixed gas thereof. These gases are also harmless to the quality of the silicon produced.

Further, at least a part of the fluid to be sprayed may be gaseous silicon chlorine compound (mainly tetrasalt-silicon). If the fluid to be sprayed is a chlorine compound of silicon, it can be expected to accelerate the reaction.

[0119] The method of converting the metal into liquid particles may be other methods. That is, a method may be used in which a metal is made into particles by a known technique in advance, supplied from a powder supply means such as a hopper into the silicon manufacturing apparatus, melted, and reacted as liquid metal particles.

[0120] According to the present invention, if silicon is produced by reacting liquid metal particles with a chlorine compound of silicon using any one of the above-described silicon production apparatuses, the number of steps can be increased as compared with the conventional silicon production method. Silicon can be manufactured at a lower cost.

[0121] In addition, in order to prevent silicon generated by the reduction reaction from remaining in the reaction space when liquid metal particles and a silicon chlorinated compound are reacted in such a silicon production method, The supply of the metal liquid particles and the supply of the silicon chloro compound to the reaction vessel may be intermittently performed, and the reaction of the metal liquid particles and the silicon chlorine compound may be performed intermittently.

In addition, the silicon manufacturing apparatus of the present invention may be configured as follows.

Still another example of the apparatus of the present invention is schematically shown in FIG. Metal particles such as high-purity aluminum prepared in advance are stored in a hopper 111 filled with an inert gas such as argon gas. A cylindrical reaction tube 112 installed vertically is heated by an external heating device 113 so that the internal temperature becomes a predetermined reaction temperature. Distilled and purified silicon tetrachloride is preheated to a predetermined temperature and supplied from the gas supply port 114. Metal particles are dropped from the hopper 111 to the upper part of the reaction tube 112 through, for example, the valve 118 and the supply tube 115. The generated silicon is accommodated in a receiver 116 connected to the lower end of the reaction tube 112. The receiver 116 is heated so that unreacted tetrasalt silicon and by-product salt aluminium do not condense. Unreacted silicon tetrachloride and by-product aluminum chloride are discharged from a gas discharge port 117 provided at the upper end of the reaction tube 112 and collected by a capacitor (not shown).

[0123] Still another example of the apparatus of the present invention is schematically shown in FIG.

The metal particle production part 7 of the apparatus is a holding / driving means 121 for holding and driving a raw metal such as aluminum, an outer container 122 for holding the metal in a holding state, a high-frequency heating coil part 123, and a spraying nozzle part 124. Composed. A linear or columnar metal 125 is prepared as a reducing metal, threaded on the outer periphery of the upper end thereof, and provided with a female thread portion, etc., and screwed into a heat insulating holder 126 made of ceramic, for example, through this holder. It is coupled to a drive shaft 127 that can rotate up and down freely.

[0124] The mantle container 122 is, for example, a stainless steel cylinder and can be provided with a water-cooled mantle. A flange is provided on the outer periphery of the upper end, and it is coupled to the rotary vertical mechanism in an airtight manner. After setting the linear or columnar metal 125 so that the runout due to rotation is reduced, the high-frequency heating coil part 123 is placed at the lower end of the outer container, and the spray nodule part 124 is placed therebelow. It adjusts so that it may correspond to the rotation center of a metal or columnar metal, and it couples in an airtight manner. It is preferable that the spray nozzle 128 appropriately set the included angle between the jet fluid and the rotation axis of the linear or columnar metal.

The lower end of the spray nozzle portion 124 is coupled to a cylindrical portion 129 made of, for example, stainless steel, and further coupled to a metal particle container 130 made of, for example, quartz having an inverted conical shape. The lower end of the metal particle container 130 is connected to a metal particle supply pipe 1 32 made of, for example, quartz via a metal particle supply valve 131. A metal particle heating device 133 is provided outside the metal particle supply pipe 132 to heat the temperature inside the metal particle supply pipe 132 to a predetermined temperature. Stainless steel cylinder An atomizing gas discharge pipe 143 is provided at the upper part of 129.

[0125] The reaction unit 8 can be installed, for example, in a transparent quartz reaction vessel 134 with a funnel-shaped floating tower 135 made of, for example, transparent quartz so that the central axis thereof coincides with the central axis of the reaction vessel.

The conical dimensions (height and inner diameter of each part) of the floating tower 135 can be set as follows.

That is, the supply amount of silicon tetrachloride per hour is, for example, 1.5 to 5 times the theoretical reaction equivalent to the supply amount of metal particles to the reaction vessel per hour, and the particles produced in the metal particle production part are Using the particle size distribution assumed to be spherical and the estimated values of the density and viscosity of tetrasalt-silicon at the reaction temperature (eg 1000 ° C) and reaction pressure (eg 1 atm), Calculate the flow velocity floating in the upward flow of salt and silicon, and set the particle floating density (the ratio of particles in the unit volume of the fluid in the reaction space) to a predetermined ratio or less.

[0126] The lower end of the floating tower 135 is connected to, for example, a quartz tetrasilicate silicon gas heating riser pipe 136 made of quartz. A reaction vessel heating device 137 is installed outside the reaction vessel 134 to heat the inside of the floating tower to a predetermined temperature.

[0127] Under the reaction section 8, the product collection section 9 is connected. The collection unit 9 includes a collection unit container 138, a receiver 139, and a collection unit container heating device 140. The collector container 138 and the receiver 139 are heated by a heating device so that metal chlorides and unreacted silicon tetrachloride as by-products do not condense.

Silicon tetrachloride is preheated from an evaporator (not shown) through a preheater, and then introduced into the upper portion of the receiver by adjusting the pressure from the silicon tetrachloride supply pipe 141.

Unreacted tetrasilicon-silicon and salt-aluminum are discharged from the reaction gas outlet 142 provided in the upper joint, and after condensation and removal of metal chloride by-produced by a capacitor not shown, tetrachloride is further added. It is preferable to liquefy and recover unreacted silicon tetrachloride with a silicon capacitor.

[0129] Using an inverted conical high-frequency induction coil, the metal is melted down at a predetermined rate, and an inert gas such as high-purity hydrogen, helium, argon, or a mixture thereof is used as the atomizing gas. And used to granulate the metal. The granulated metal particles are stored in a quartz metal particle container 130 and supplied to the upper portion of the floating tower 135 in the reaction container 134 through a valve 131 at a predetermined rate.

[0130] Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these descriptions.

(Example 1)

Silicon was manufactured using the apparatus schematically shown in FIG. Spherical particles having a particle size of 20 μm and a particle size of 60 μm having an purity of about 99.995% purity prepared in advance were stored in a hopper 111 filled with argon gas. A vertically installed quartz reaction tube 112 made of quartz having an inner diameter of about 120 mm and a height of about 1800 mm was heated by an external heating device 113 so that the internal temperature became 1000 ± 20 ° C. Distilled and purified silicon tetrachloride was preheated to about 400 ° C. and supplied from the gas supply port 114 at a rate of about 560 g / hr. The sample was dropped from the hopper 111 through the metal particle supply pipe 115 heated to about 400 ° C. onto the upper part of the reaction pipe 112 at a rate of about 60 g / hr. The generated silicon was accommodated in a receiver 116 connected to the lower end of the reaction tube 112. The receiver 116 was kept at about 700 ° C. so that unreacted silicon tetrachloride and by-product aluminum chloride did not condense. Unreacted silicon tetrachloride and by-product aluminum chloride were discharged from a gas discharge port 117 provided at the upper end of the reaction tube 112 and collected by a capacitor (not shown). The product in the receiver 116 was treated with hydrochloric acid to obtain silicon. As a result of the reaction for about 2 hours, about 85 g of silicon was obtained.

[0131] (Example 2)

Except for the spherical aluminum particles used in Example 1, the particle size of 60 μm, the force of 85 μm, the supply rate of silicon tetrachloride was about 6.4 kg / hr, and the supply rate of aluminum was about 670 g / hr. Reaction was performed under the same conditions as in Example 1 to obtain about 900 g of silicon.

[0132] (Example 3)

Fig. 4 shows how the tetrasaltum silicon is returned with granular aluminum using the apparatus schematically shown. I did the original.

As a reducing metal, we prepared aluminum billet 125 with a diameter of about 40mm, a length of about 450mm, and a purity of about 99.995% processed within a straightness of lmm. The outer periphery of the upper end of about 50 mm was threaded, screwed into an alumina ceramic heat insulating holder 126 provided with a female thread portion, and connected to a rotatable drive shaft 127 via this holder.

[0133] The mantle container 122 was a stainless steel cylindrical shape having an inner diameter of about 160 mm and a height of about 500 mm, and was equipped with a water-cooled mantle. After setting the aluminum billet 125 so that the runout due to rotation is within lmm, the coil portion 123 for high-frequency heating is placed at the lower end of the outer casing, and the nozzle portion 124 for spraying is placed below it. It was adjusted to match the center of rotation and assembled in an airtight manner. The spray nozzle 128 was set so that the included angle between the ejected fluid and the rotation axis of the aluminum billet was about 45 °.

[0134] The cylindrical portion 129 was made of stainless steel having an inner diameter of about 400 mm and a height of about 600 mm, and an inverted conical quartz metal particle container 130 having a height of about 460 mm was coupled thereto. The lower end of the metal particle container 130 is connected through a metal particle supply valve 131 to a stone particle supply pipe 132 made of stone and having an inner diameter of about 20 mm and a height of about 1000 mm. A metal particle heating device 133 is provided outside the metal particle supply pipe 132, and the temperature inside the metal particle supply pipe 132 is heated to about 600 ° C.

In the reaction section 8, a transparent quartz funnel-shaped floating tower 135 was installed in a transparent quartz reaction vessel 134 having an inner diameter of about 300 mm and a height of about 1200 mm so that the central axis thereof coincided with the central axis of the reaction vessel. The inner diameter of the upper end of the floating tower 135 was about 200 mm, the inner diameter of the lower part was about 15 mm, and the height was about 800 mm.

[0135] The conical dimensions (height and inner diameter of each part) of the floating tower 135 were set as follows.

In other words, the amount of silicon tetrachloride supplied per hour is 1.6 times the theoretical reaction equivalent of the amount of metal particles supplied to the reaction vessel per hour, and the particles produced in the metal particle production part are spherical. Using the estimated particle size distribution and estimated values of silicon tetrachloride density and viscosity at a reaction temperature of 1000 ° C and a pressure of 1 atm, particles float in the upward flow of silicon tetrachloride under the reaction conditions. The buoyant density of particles (the proportion of particles in the unit volume of fluid in the reaction space) was set to 30% or less. Silicon tetrachloride gas heating riser 136 is made of quartz with an inner diameter of about 15 mm and a height of about 600 mm. [0136] The inside of the floating tower was heated to about 1000 ° C by the reaction vessel heating device 137. The collector container 138 and the receiver 139 were kept warm at about 700 ° C. Tetrahydrous silicon is preheated from an evaporator (not shown) through a preheater to about 500 ° C and then adjusted to about 1 atm from the silicon tetrachloride supply port 141 at a rate of about 1.6 KgZhr. Introduced at the top.

[0137] Using an inverted conical high-frequency induction coil, aluminum was melted down at a rate of about 18 gZsec with high-frequency power of about 100 kHz and 40 kWH, and high purity argon with a dew point of 20 ° C or less was used as the atomizing gas. Was used to granulate aluminum. The granulated anode particles were stored in a quartz metal particle container 130 and supplied to the upper part of the floating tower 135 in the reaction container 134 at a rate of about 200 g / hr through a valve 131.

[0138] After approximately 5 hours of reaction, the product in receiver 139 was removed and treated with a hydrochloric acid solution to obtain about 900 g of silicon.

[0139] The present invention is not limited to the above embodiment. The above-described embodiment is an example, and has substantially the same configuration as the technical idea described in the claims of the present invention, and the one that exhibits the same function and effect is a good one. However, it is included in the technical scope of the present invention.

Claims

The scope of the claims

[1] A method for producing silicon by reducing a chlorine compound of silicon, wherein at least the metal is made into liquid particles, the liquid particles of the metal are brought into contact with gaseous silicon chlorine compound, and the silicon is produced. A method for producing silicon, characterized in that silicon is produced by reducing said chlorine compound.

[2] When the metal liquid particles are brought into contact with and reacted with gaseous silicon chlorine compound, the gaseous silicon chlorine compound and the metal liquid particles are brought into contact in a countercurrent manner. Item 2. A method for producing silicon according to Item 1.

3. The method for producing silicon according to claim 1, wherein when the metal liquid particles are brought into contact with and reacted with gaseous silicon chlorine compound, the metal liquid particles are brought into a floating state.

4. The method for producing silicon according to any one of claims 1 to 3, wherein a main component of the chlorine compound of silicon is silicon tetrachloride.

5. The method for producing silicon according to claim 4, wherein the silicon tetrachloride is produced by allowing carbon and chlorine to act on silica stone.

[6] The value of the free energy per chlorine atom in the metal chloride as the liquid particle is higher than the free energy value per chlorine atom in the chlorine compound of silicon. 6. The method for producing silicon according to claim 1, wherein the metal used as the liquid particles has a low melting point and a lower melting point than that of silicon. 7. The method for producing silicon according to claim 1, wherein the metal used as the liquid particles is aluminum or zinc and a displacement force. [8] The method for producing silicon according to any one of claims 1 to claim 7, characterized in that a 20 to 200 _beta m particle diameter of the metal liquid particles.

[9] The temperature according to any one of claims 1 to 8, wherein a temperature at which the metal liquid particles are brought into contact with and reacted with gaseous chlorine compound of silicon is 800 ° C or higher. The manufacturing method of the silicon | silicone described.

[10] The pressure according to any one of [1] to [9], wherein the pressure at the time of bringing the metal liquid particles into contact with and reacting with the gaseous chlorine compound of silicon is 1 atm or more. The manufacturing method of the said silicon | silicone.

[11] The supply of the liquid metal particles and the supply of the chlorine compound of silicon are intermittently performed, and the contact and reaction of the liquid metal particles and the chlorine compound of silicon are intermittently performed. The method for producing silicon according to any one of claims 1 to 10.

[12] The method for producing silicon according to any one of claims 1 to 11, wherein the metal is made into liquid particles by melting metal solid particles into metal liquid particles. A method for producing silicon, characterized in that

[13] The method for producing silicon according to any one of claims 1 to 11, wherein the metal is a liquid particle, the central axis of a linear or columnar metal is oriented in a vertical direction, The lower end portion of the linear or columnar metal is heated and melted to flow down as a liquid metal, and the metal particles produced by spraying a fluid onto the flowing down liquid metal are made liquid. To manufacture silicon.

[14] The heating or melting of the linear or columnar metal is performed by high frequency induction heating. The method for producing silicon according to claim 13.

[15] The production of silicon according to claim 13 or 14, wherein the heat-melting of the linear or columnar metal is performed while rotating the linear or columnar metal around its central axis. Method.

[16] The method for producing silicon according to any one of claims 13 to 15, wherein the fluid to be sprayed is any one of hydrogen, helium, argon, or a mixture thereof.

17. The method for producing silicon according to any one of claims 13 to 16, wherein the fluid to be sprayed contains a chlorine compound of the silicon.

[18] A silicon manufacturing apparatus, at least,

A reaction vessel for reacting metal particles with gaseous silicon chlorine compound, means for heating the reaction vessel,

Means for supplying particles of the metal into the reaction vessel;

Means for supplying a chlorine compound of the silicon into the reaction vessel;

Means for draining the fluid in the reaction vessel;

A container for collecting the generated silicon;

An apparatus for producing silicon, comprising:

19. The apparatus for producing silicon according to claim 18, further comprising means for suspending particles in the reaction vessel.

[20] The floating means has a funnel shape whose horizontal cross-sectional area expands from the bottom to the top, and the chlorine compound of silicon is supplied from the bottom of the floating means in the reaction space. The particles according to claim 19, wherein the particles are suspended. The silicon production equipment listed.

21. The silicon according to claim 20, wherein an enlargement ratio of a horizontal sectional area of the floating means is set to correspond to a particle size distribution of the metal particles. Manufacturing equipment.

22. The silicon manufacturing apparatus according to any one of claims 19 to 21, wherein the floating means has a structure that causes a part of particles to overflow.

23. The silicon manufacturing apparatus according to claim 18, wherein at least the material of the reaction vessel is quartz.

24. The silicon production apparatus according to any one of claims 18 to 23, wherein at least an inner wall of the reaction vessel is made of quartz or silicon.

[25] The means for supplying the silicon chlorine compound is characterized in that the silicon chlorine compound supplied to the reaction vessel in the reaction vessel is preliminarily heated by means for heating the reaction vessel. 25. The silicon manufacturing apparatus according to any one of claims 18 to 24.

[26] Claim 18, No. 25, No. 25, and a silicon manufacturing apparatus according to any one of claims, further,

Means for controlling the amount of metal particles supplied;

Means for controlling the supply amount of chlorine compound of the silicon,

Means for controlling the temperature of the reaction space in the reaction vessel;

Means for controlling the pressure in the reaction vessel;

Any of these forces A device for producing silicon characterized by comprising four or more means. [27] The silicon production apparatus according to any one of [18] and [26], further comprising means for collecting a by-product in the reaction.

[28] The silicon according to any one of [18] to [27], further comprising at least one of means for collecting unreacted silicon chlorine compounds and means for recirculating. Manufacturing equipment.

[29] The container for collecting the generated silicon includes means for heating the silicon collected in the container. Silicon manufacturing equipment.

[30] The method of claim 29, wherein the means for heating the silicon collected in the container melts and collects the collected silicon in a unidirectional force. Manufacturing equipment.

31. The silicon manufacturing apparatus according to claim 18, further comprising means for supplying a chlorine compound of silicon to the container for collecting the generated silicon. .

[32] The silicon production apparatus according to any one of claims 18 to 31 is used to produce silicon by reacting liquid metal particles with a chlorine compound of silicon. Silicon manufacturing method.

[33] The supply of the metal particles to the reaction vessel and the supply of the chlorine compound of silicon are intermittently performed, and the reaction between the liquid metal particles and the chlorine compound of silicon is intermittently performed. The method for producing silicon according to claim 32.

[34] The gaseous silicon chlorine compound and the liquid metal particles are contacted and reacted in a countercurrent manner. 34. The method for producing silicon according to claim 32 or claim 33, wherein: 34. The method for producing silicon according to claim 32 or claim 33, wherein particles in the reaction are suspended.