JP2009208999A - Method of manufacturing tetrachlorosilane fluid and method of manufacturing silicon particles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of efficiently manufacturing tetrachlorosilane fluid of a high temperature and high pressure usable in a gas atomizing method or the like and a method of manufacturing silicon particles using the tetrachlorosilane fluid. <P>SOLUTION: The method of manufacturing the tetrachlorosilane fluid is provided with a pressurizing step of: pressurizing liquefied tetrachlorosilane; and a heating step of: heating the tetrachlorosilane pressurized in the pressurizing step to form a gas or a supercritical fluid. The method of manufacturing the silicon particles is carried out by blowing an atomizing gas containing tetrachlorosilane obtained by the method of manufacturing the tetrachlorosilane fluid to the molten metal to form the fine droplets of the molten metal and bringing the resultant fine droplets of the molten metal into contact with tetrachlorosilane to reduce the tetrachlorosilane to obtain the silicon particles. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a high-temperature and high-pressure tetrachlorosilane fluid, and a method for producing silicon particles using the tetrachlorosilane fluid obtained thereby.

  As environmental problems are highlighted, solar cells are attracting attention as a clean energy source, and demand is rapidly increasing mainly for residential use. Since silicon-based solar cells are excellent in reliability and conversion efficiency, they account for about 80% of solar power generation. However, in order to further reduce the unit price of power generation, it is desired to secure a low-cost silicon raw material.

  Currently, the Siemens method for thermally decomposing trichlorosilane is mainly used as a method for producing high-purity silicon. However, this method is said to be difficult to further reduce costs because there is a limit to the reduction in power consumption.

As a method for replacing pyrolysis, a method of reducing chlorosilane using a molten metal such as zinc or aluminum can be used. For example, Patent Document 1 describes a method of obtaining silicon particles by reducing tetrachlorosilane gas by spraying molten aluminum in a tetrachlorosilane (SiCl ₄ ) atmosphere (Example 1 of Patent Document 1). See). In the above method, the reaction represented by the following formula (A) proceeds.
3SiCl ₄ + 4Al → 3Si + 4AlCl ₃ (A)
Japanese Patent Laid-Open No. 2-64006

  By the way, as a method for forming fine droplets of molten metal, a gas atomizing method is known in which a gas is blown onto molten metal flowing down from a nozzle. In this gas atomizing method, it is common to use an inert gas as a gas (hereinafter referred to as “atomizing gas”) sprayed on the molten metal.

  However, the present inventor has found that there is room for improvement in the following points when the gas atomization method using an inert gas is employed in the production of silicon particles. That is, a large amount of inert gas used for atomization of the molten metal remains in the reaction field where the tetrachlorosilane gas is reduced and silicon particles are deposited. That is, if the inert gas remains in the reaction field, it becomes difficult to sufficiently increase the partial pressure of the tetrachlorosilane gas, and the temperature of the reaction field also decreases, so that sufficient reactivity cannot be obtained.

  The present invention has been made in view of the above problems, and provides a method for efficiently producing a high-temperature and high-pressure tetrachlorosilane fluid that can be used in a gas atomizing method and the like, and a method for producing silicon particles using the tetrachlorosilane fluid. The purpose is to do.

  The method for producing a tetrachlorosilane fluid according to the present invention includes a pressurizing step of pressurizing liquefied tetrachlorosilane, and a heating step of heating the liquefied tetrachlorosilane pressurized in this pressurizing step to make a gas or a supercritical fluid. It is characterized by providing.

  According to this method, since the liquefied tetrachlorosilane is pressurized, the pressure can be easily increased with an inexpensive apparatus as compared with the case where gaseous tetrachlorosilane is pressurized. Then, by heating the liquefied tetrachlorosilane to a gas or supercritical fluid after the pressurizing step, a high-temperature and high-pressure tetrachlorosilane fluid can be efficiently produced. Since tetrachlorosilane has a boiling point of 57 ° C., it is liquid at room temperature and atmospheric pressure. The critical point of tetrachlorosilane is a temperature of 235 ° C. and a pressure of 3.75 MPa.

  The tetrachlorosilane fluid obtained through the heating step preferably has a pressure of 0.1 to 15 MPa and a temperature of 200 to 1200 ° C. The tetrachlorosilane fluid in the above pressure range and temperature range is suitable for use in a method for producing silicon particles by gas atomization.

  In the method for producing silicon particles according to the present invention, the high-temperature and high-pressure tetrachlorosilane fluid produced as described above is supplied to the first nozzle and directed to the molten metal discharged from the second nozzle. The atomization process which forms the micro droplet of the molten metal by injecting the atomization gas containing tetrachlorosilane from the nozzle of the nozzle, in this atomization process, by bringing the micro droplet into contact with tetrachlorosilane, It is characterized by obtaining silicon particles by reduction.

  In the method for producing silicon particles according to the present invention, an atomized gas containing tetrachlorosilane is sprayed onto the molten metal. As a result, the amount of inert gas remaining in the reaction field can be reduced as compared with the case of using an atomized gas consisting of only an inert gas. Further, according to the manufacturing method of the present invention, molten metal microdroplets are formed by atomizing gas injection, and at the same time, tetrachlorosilane contained in the atomized gas and the molten metal microdroplets come into efficient contact. . Therefore, according to the present invention, a sufficiently high reaction rate can be achieved in the reaction between molten metal droplets and tetrachlorosilane.

  In the method for producing silicon particles according to the present invention, the atomizing gas preferably has a tetrachlorosilane concentration of 10% by volume or more. Further, the atomizing gas may contain only a tetrachlorosilane fluid produced by the above method according to the present invention without containing an inert gas or the like. Thereby, the reduction reaction of tetrachlorosilane proceeds more efficiently in the reaction field, and a high reaction rate can be achieved.

  Note that “supplying the tetrachlorosilane fluid to the first nozzle” here refers not only to supplying the tetrachlorosilane fluid alone to the first nozzle, but also to supplying the tetrachlorosilane fluid to another fluid (for example, non-feeding). It also includes the case where the first nozzle is supplied in a state of being mixed with the active gas.

  The atomizing gas may be a mixed gas of a tetrachlorosilane fluid and an inert gas produced by the above method according to the present invention. As the inert gas contained in the atomizing gas, argon and / or helium are suitable.

  In the method for producing silicon particles according to the present invention, the molten metal preferably contains one kind selected from the group consisting of Na, K, Mg, Ca, Zn, and Al alone or two or more kinds. In particular, the molten metal is preferably aluminum. Thereby, even if a metal remains in the generated silicon particles or on the surface thereof, it is easy to remove the metal by dissolution or segregation using an acid or alkali.

  In the atomizing step, it is preferable that atomized gas is injected at a pressure of 0.1 to 15 MPa toward the molten metal. By injecting atomized gas under such pressure conditions, it is possible to suitably perform both formation of fine droplets of molten metal and formation of silicon particles by a reduction reaction of tetrachlorosilane.

  According to the method for producing a tetrachlorosilane fluid according to the present invention, a high-temperature and high-pressure tetrachlorosilane fluid can be efficiently produced. In addition, according to the method for producing silicon particles according to the present invention, a sufficiently high reaction rate can be achieved in the reaction between fine droplets of molten metal formed by gas atomization and tetrachlorosilane.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

The method for producing silicon particles according to the present embodiment includes an atomizing step of forming fine droplets of molten aluminum by spraying atomized gas on a trickle of molten aluminum. In this atomizing process, a gas containing tetrachlorosilane (SiCl ₄ ) is used as an atomizing gas, and the reduction reaction represented by the following formula (A) proceeds by bringing tetrachlorosilane and molten aluminum fine droplets into contact with each other. Then, silicon particles are produced.
3SiCl ₄ + 4Al → 3Si + 4AlCl ₃ (A)

(Method for producing high-temperature and high-pressure tetrachlorosilane fluid)
First, a method for producing a high-temperature and high-pressure tetrachlorosilane fluid used in this embodiment will be described.

  The manufacturing method of the tetrachlorosilane gas employ | adopted in this embodiment is equipped with the pressurization process which pressurizes liquefied tetrachlorosilane, and the heating process which heats the pressurized liquefied tetrachlorosilane and makes it a gas or a supercritical fluid. According to this method, since the liquefied tetrachlorosilane is pressurized, there is an advantage that the pressure can be increased easily with an inexpensive apparatus, compared with the case where gaseous tetrachlorosilane is pressurized. Then, by heating the liquefied tetrachlorosilane to a gas or supercritical fluid after the pressurizing step, a high-temperature and high-pressure tetrasilane fluid can be efficiently produced.

  There is no restriction | limiting in particular as a method of pressurizing liquefied tetrachlorosilane, For example, the method using a plunger pump, a diaphragm pump, etc. is mentioned.

  The method for heating the pressurized liquefied tetrachlorosilane to form a gas or a supercritical fluid is not particularly limited, and examples thereof include a method using high frequency heating, resistance heating, lamp heating and the like.

  The pressure of the tetrachlorosilane fluid obtained through the pressurizing step and the heating step is preferably 0.1 to 15 MPa, more preferably 1 to 10 MPa, and still more preferably 2 to 10 MPa.

  When the pressure of the tetrachlorosilane fluid is less than 0.1 MPa, the production of atomized gas used in the production of silicon particles described later tends to be inefficient. That is, when the atomizing gas to be used is a mixed gas of a tetrachlorosilane fluid and an inert gas, if the pressure of the tetrachlorosilane fluid is less than 0.1 MPa, tetrachlorosilane gas or atomizing gas is used in the atomizing gas production process. It becomes necessary to pressurize again. Also, when the atomizing gas used is a tetrachlorosilane fluid alone, if the pressure of the tetrachlorosilane fluid is less than 0.1 MPa, it is necessary to pressurize the tetrachlorosilane fluid again. On the other hand, in order to use the atomized gas exceeding 15 MPa, it is necessary to use various devices having high pressure resistance, and the cost tends to increase.

  The temperature of the tetrachlorosilane fluid obtained through the pressurization step and the heating step is preferably 200 to 1200 ° C, and more preferably 200 to 1000 ° C.

  When the temperature of the tetrachlorosilane fluid is less than 200 ° C., the production of atomized gas used in the production of silicon particles tends to be inefficient. That is, when the temperature of the tetrachlorosilane fluid is lower than 200 ° C., it is necessary to heat the tetrachlorosilane fluid or the atomized gas again in the process of producing the atomized gas. On the other hand, even if the temperature of the tetrachlorosilane fluid exceeds 1200 ° C., the effect corresponding to the cost required is small.

  In order to suppress metal corrosion due to tetrachlorosilane, the container, pressurizing device, and heating device that contain the high-temperature and high-pressure tetrachlorosilane fluid are preferably made of a highly corrosion-resistant material. Examples of metal materials having high resistance to corrosion by tetrachlorosilane include Ni-based alloys and stainless steel.

(Method for producing silicon particles)
Next, the configuration of the reaction apparatus 10 suitable for the production method according to this embodiment and the operating conditions thereof will be described in detail with reference to FIGS. FIG. 1 is a schematic configuration diagram showing the configuration of the reaction apparatus according to the present embodiment. FIG. 2 is an enlarged view showing the atomizing mechanism of the reaction apparatus 10. The atomizing mechanism of the reaction apparatus 10 includes a nozzle 1a of the molten metal containing unit 1 and an atomizing gas injection unit 2 described later.

  A reaction apparatus 10 shown in FIG. 1 includes a molten metal storage unit 1, an atomized gas injection unit 2, a reactor 3, a solid-gas separator 5, and a pipe (hereinafter referred to as “line” in some cases) for connecting them. .

  The molten metal container 1 is for containing molten aluminum and is provided in the sealed container 15. A heater 11 is provided around the molten metal container 1 so that the temperature of the molten aluminum to be accommodated can be adjusted. As shown in FIG. 2, a nozzle (second nozzle) 1a extending to the inside of the reactor 3 is provided at the bottom of the molten metal container 1, and a trickle F of molten aluminum flows down from the nozzle 1a in the vertical direction. To do. When the molten aluminum is accommodated in the molten metal container 1 in this way, the molten aluminum can be stably flowed into the reactor 3 from the nozzle 1a, and silicon particles are produced stably and continuously. There is an advantage that you can. Moreover, you may pressurize the inside of the airtight container 15 which accommodates the molten metal accommodating part 1 with an inert gas. Thereby, molten aluminum can flow down more stably.

  The molten aluminum flowing down from the nozzle 1a preferably has a purity of 99.9% by mass or more, more preferably 99.99% by mass or more, and further preferably 99.995% by mass or more. By using high-purity molten aluminum, high-purity silicon particles can be obtained. The purity of molten aluminum here refers to the content (mass%) of Fe, Cu, Ga, Ti, Ni, Na, Mg, and Zn among the elements measured by glow discharge mass spectrometry of the raw material aluminum. Is the value obtained by subtracting the total of 100% by mass.

  The temperature in the molten metal container 1 may be appropriately set according to the melting point of the metal to be melted. However, when aluminum (melting point: 660 ° C.) is used as the molten metal as in this embodiment, it is usually 700. It is -1300 degreeC, Preferably it is 700-1200 degreeC, More preferably, it is 700-1000 degreeC. The temperature of the nozzle 1a is preferably about 700 to 1000 ° C.

  As shown in FIG. 2, the atomizing gas injection unit 2 is for injecting atomized gas supplied through a line L <b> 1 toward a trickle F of molten aluminum. The atomizing gas injection unit 2 includes a nozzle (first nozzle) 2a that injects an atomizing gas G from its periphery toward a trickle F of molten aluminum. By spraying the atomizing gas G on the trickle F, fine droplets P of molten aluminum are formed.

  In the present embodiment, the atomizing gas injected from the nozzle 2a is a mixed gas of tetrachlorosilane and an inert gas. As the inert gas contained in the atomizing gas, argon and / or helium are suitable.

  The concentration of tetrachlorosilane in the atomized gas is preferably 10% by volume or more, more preferably 20% by volume or more, and still more preferably 50% by volume or more. There exists a tendency for reaction of the said Formula (A) not to fully advance that the density | concentration of tetrachlorosilane is less than 10 volume%.

  From the viewpoint of obtaining high-purity silicon particles, the tetrachlorosilane used for the preparation of the atomizing gas preferably has a purity of 99.99% by mass or more, more preferably 99.999% by mass or more. More preferably, it is 9999% by mass or more.

  From the viewpoint of obtaining high-purity silicon particles, the inert gas used for the preparation of the atomizing gas preferably has a purity of 99.9% by volume or more, more preferably 99.99% by volume or more, More preferably, it is 99.999 volume% or more, and it is especially preferable that it is 99.9995 volume% or more.

  The temperature of the atomizing gas sprayed on the trickle F of molten aluminum is preferably 200 to 1200 ° C, more preferably 200 to 1000 ° C. By increasing the temperature of the atomizing gas, the atomization efficiency is improved, that is, the molten aluminum is easily atomized. As a method of preparing an atomized gas having a higher temperature, a method in which an inert gas having no corrosive property is heated to a temperature higher than the temperature of the tetrachlorosilane fluid, and the inert gas and the tetrachlorosilane fluid are mixed. Is mentioned.

  The pressure of the atomizing gas sprayed on the trickle F of molten aluminum is preferably 0.1 to 15 MPa, more preferably 1 to 10 MPa, and further preferably 2 to 10 MPa. If the atomizing gas pressure is less than 0.1 MPa, the formation of molten aluminum microdroplets P tends to be insufficient and the reaction represented by the above formula (A) tends to be insufficient. On the other hand, in order to use atomized gas exceeding 15 MPa, it is necessary to use various devices with high pressure resistance, and the cost tends to increase. Note that the atomized gas may be a liquid or a supercritical fluid depending on the temperature condition and the pressure condition before being discharged from the nozzle 2a.

  In order to suppress metal corrosion caused by tetrachlorosilane, the nozzle 2a may be made of a member made of alumina, silicon carbide, silicon nitride, quartz, mullite, or carbon, or a member formed of a member coated with the above material. preferable.

  As shown in FIG. 1, the reactor 3 includes a cylindrical portion 3a extending in the vertical direction, and a reaction field in which the reaction represented by the above formula (A) proceeds is formed in the cylindrical portion 3a. By spraying atomized gas from the nozzle 2a, molten aluminum microdroplets P are formed, and at the same time, tetrachlorosilane and microdroplets P contained in the atomized gas come into contact with each other. The reduction reaction (formula (A) above) proceeds.

As shown in the above formula (A), the stoichiometric ratio of the number of moles of tetrachlorosilane and the number of moles of molten aluminum in the reaction is 3: 4. From the viewpoint of productivity, the unit time supplied to the reaction field The ratio (M ₁ / M ₂ ) between the number of moles of tetrachlorosilane M ₁ and the number of moles M ₂ of molten aluminum supplied is preferably 0.75-20, more preferably 0.75-10. Preferably, it is 0.75-7.5. If the value of M ₁ / M ₂ is less than 0.75, the progress of the reaction tends to be insufficient, whereas if it exceeds 20, the amount of tetrachlorosilane that does not contribute to the reaction tends to increase.

  A heater 13 is provided around the cylindrical portion 3a so that the temperature of the reaction field can be adjusted. The heating method is not particularly limited. For example, in addition to a direct method using high-frequency heating, resistance heating, lamp heating, or the like, a method using a fluid such as a gas whose temperature is adjusted in advance can be used. The temperature of the reaction field is usually adjusted to be 300 to 1200 ° C. (preferably 500 to 1000 ° C.). Moreover, the pressure in the reaction field is usually adjusted to be 1 atm or higher.

  The oxygen concentration in the reaction field formed in the cylindrical portion 3a is preferably maintained as low as possible from the viewpoint of sufficiently suppressing the formation of oxides. Specifically, the oxygen concentration in the reaction field before starting the reaction is preferably 1% by volume or less, more preferably 0.1% by volume or less, and further preferably 100% by volume or less. It is preferably 10 ppm by volume or less, particularly preferably. As a method for lowering the oxygen concentration in the reaction field before the start of the reaction, there is a technique in which molten aluminum is sprayed for a predetermined time, and oxygen in the reaction field is adsorbed to aluminum droplets. In addition, as for the reaction field before starting reaction, it is preferable that a dew point is -20 degrees C or less, It is more preferable that it is -40 degrees C or less, It is still more preferable that it is -70 degrees C or less.

  In addition, the oxygen concentration in the reaction field is preferably maintained as low as possible from the viewpoint of sufficiently suppressing the formation of oxides even during the reaction. Specifically, the oxygen concentration in the reaction field during the reaction is preferably 1% by volume or less, more preferably 0.1% by volume or less, still more preferably 100% by volume or less. It is particularly preferable that the volume be ppm or less.

The reactor 3 includes a reduced diameter portion 3b having a Si particle discharge port 3c for discharging silicon particles at the lower end and decreasing the inner diameter as it goes downward in the lower part thereof. A gas discharge port 3d for discharging AlCl ₃ (gas) generated by the reaction, unreacted SiCl ₄ (gas) and fine silicon particles is provided at a substantially intermediate position in the vertical direction of the reduced diameter portion 3b. It has been.

The reduced diameter portion 3b provided at the lower portion of the reactor 3 functions as a first-stage solid-gas separator. A heater (not shown) is provided around the reduced diameter portion 3b so that the internal temperature can be adjusted. By maintaining the temperature inside the reduced diameter portion 3b at a temperature at which AlCl ₃ (sublimation point: 180 ° C.) does not precipitate, the silicon particles and the gas are separated. Specifically, it is preferable to adjust the temperature inside the reduced diameter portion 3b to be 200 ° C. or higher. When the temperature inside the reduced diameter portion 3b is lower than 200 ° C., AlCl ₃ tends to be precipitated in the reduced diameter portion 3b and easily mixed into silicon particles.

  The gas discharged from the gas discharge port 3d is supplied to the solid-gas separator 5. The solid gas separator 5 functions as a second stage solid gas separator. The solid-gas separator 5 is for separating silicon particles present in the gas discharged from the gas discharge port 3d. It is preferable to adjust the temperature inside the solid-gas separator 5 to be 200 ° C. or higher. As a suitable example of the solid gas separator 5, a heat insulation cyclone type solid gas separator can be exemplified.

The gas discharged from the solid gas separator 5 is supplied to the solid gas separator 8. The solid gas separator 8 functions as a third-stage solid gas separator. The solid gas separator 8 is for removing AlCl ₃ contained in the gas from the solid gas separator 5. By maintaining the temperature in the solid-gas separator 8 at a temperature at which AlCl ₃ is precipitated but SiCl ₄ (boiling point: 57 ° C.) is not condensed, the deposited AlCl ₃ (solid) is removed. Specifically, it is preferable to maintain the internal temperature of the solid-gas separator 8 at 60 to 170 ° C. (more preferably 70 to 100 ° C.). When the temperature inside the solid-gas separator 8 is lower than 60 ° C., the SiCl ₄ is condensed in the solid-gas separator 8 and the amount of SiCl ₄ gas to be recycled tends to be insufficient. On the other hand, if it is higher than 170 ° C. The internal temperature of the solid-gas separator 8, precipitation of AlCl ₃ becomes insufficient, there is a tendency that the content is increased in the AlCl ₃ of SiCl ₄ gas to be recycled.

It is preferable that the solid-gas separator 8 includes a baffle plate (not shown) therein. By providing the baffle plate inside, the inner surface area of the solid-gas separator 8 is increased, AlCl ₃ is efficiently precipitated, and the content of AlCl ₃ in the gas can be sufficiently reduced. The internal surface area of the solid-gas separator 8 is preferably 5 times or more the device surface area of the solid-gas separator 8.

The gas from which AlCl ₃ is removed in the solid-gas separator 8 is discharged from the solid-gas separator 8 through the line L7. When the unreacted tetrachlorosilane gas and the inert gas coexist in the gas, the tetrachlorosilane gas can be recovered by separating the inert gas and performing purification as necessary. This tetrachlorosilane gas may be recycled as a reactive gas. The separated inert gas may also be recycled.

  Thus, the reaction apparatus 10 according to the present embodiment includes the reduced diameter portion 3b as the first-stage solid-gas separator, the solid-gas separator 5 as the second-stage solid-gas separator, The solid-gas separator 8 is provided as a third-stage solid-gas separator. By adopting such a configuration, unreacted tetrachlorosilane gas can be efficiently recovered and reused. For example, it can be reused as part of the atomized gas. The number of stages of the solid-gas separator is not particularly limited. For example, the reduced diameter portion 3b and the solid-gas separator 8 may be connected without using the solid-gas separator 5, or the solid-gas separator may be connected. Four or more stages may be provided. In addition, when using a reactor that does not include the gas discharge port 3d, a solid-gas separator 5 or the like may be installed downstream of the Si particle discharge port 3c.

  According to the method for manufacturing silicon particles according to the present embodiment, the following effects are exhibited. That is, since an atomized gas containing tetrachlorosilane is used, the amount of the inert gas remaining in the reaction field can be reduced as compared with the case where an atomized gas made of an inert gas is used. Simultaneously with the formation of the molten aluminum microdroplet P, the microdroplet P and the tetrachlorosilane contained in the atomizing gas efficiently come into contact, and the reduction reaction of tetrachlorosilane by the microdroplet P proceeds. As a result, a sufficiently high reaction rate can be achieved in the reduction reaction of tetrachlorosilane by the fine droplets P.

  Further, by employing the silicon particle production method according to the present embodiment, there is an advantage that the silicon particles can be produced by a reaction apparatus having a relatively simple configuration. That is, in the conventional silicon particle manufacturing method using the gas atomization method, an inert gas (atomizing gas) supply means for forming microdroplets, and a tetra contacted with the formed microdroplets are used. A reactor equipped with both means for supplying chlorosilane gas is required. On the other hand, according to the method for producing silicon particles according to the present embodiment, since silicon particles can be produced by injecting atomized gas, tetrachlorosilane gas is separately added to the reactor as in the reactor 10 shown in FIG. The reaction apparatus which does not comprise the mechanism supplied to 3 can be used. However, you may use the reaction apparatus which comprises the mechanism which supplies tetrachlorosilane gas to the reactor 3 separately.

  In the present embodiment, the case where the atomized gas prepared in advance by mixing the tetrachlorosilane fluid and the inert gas is used as an example. However, the tetrachlorosilane fluid is added to the inert gas and the reactor 10 is used. An atomized gas may be prepared. More specifically, the line L1 is connected to an inert gas supply source, and an atomized gas is prepared by continuously adding a tetrachlorosilane fluid to the inert gas flowing in the line L1, and this is injected into the atomized gas. You may supply to the part 2. By adopting such a configuration, there is an advantage that the tetrachlorosilane concentration of the atomizing gas can be appropriately changed according to the reaction conditions and the like.

  Further, the atomizing gas is not necessarily a mixed gas of tetrachlorosilane gas and inert gas, and may be a tetrachlorosilane fluid alone. By adopting such a configuration, the partial pressure of tetrachlorosilane in the reaction field can be further increased, and a higher reaction rate can be achieved.

  The preferred embodiment of the present invention has been described in detail above, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the case where aluminum is used as the molten metal is illustrated, but the present invention is not limited to this, and one type selected from the group consisting of Na, K, Mg, Ca and Zn is used alone. Alternatively, two or more selected from the group consisting of Na, K, Mg, Ca, Zn and Al may be used in appropriate combination. Moreover, you may use the alloy of aluminum and silicon as a molten metal.

  Furthermore, in the above-described embodiment, as shown in FIG. 2, a so-called free fall method is adopted in which after a trickle F of molten aluminum flows down from the nozzle 1 a in the atomizing step, atomized gas G sprayed from the nozzle 2 a is blown. Although cases have been illustrated, other gas atomization methods may be employed. For example, as shown in FIG. 3, a so-called confined method (Close-Coupled method) using an apparatus having an atomizing mechanism in which an outlet of molten aluminum of the nozzle 1a and an outlet of atomized gas of the nozzle 2a are provided close to each other is used. ) May be adopted.

  Moreover, although the case where molten aluminum was discharged downward from the nozzle 1a was illustrated in the said embodiment, what is called an updraft atomizer apparatus may be used and molten aluminum may be discharged upwards.

  Further, when the molten metal is discharged upward or downward, the halogenated silane gas may flow in the same direction as the direction of movement of the molten metal (cocurrent flow), facing the direction of movement of the molten metal. Halogenated silane gas may be flowed (counterflow).

It is a schematic block diagram which shows the structure of the reaction apparatus which concerns on suitable embodiment of the manufacturing method of a silicon particle. It is sectional drawing which shows the structure of the atomizing mechanism with which the reaction apparatus shown in FIG. 1 is provided. It is sectional drawing which shows the other form of the atomizing mechanism applicable in the manufacturing method of the silicon particle which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Molten metal accommodating part, 1a ... Nozzle for molten metal (2nd nozzle), 2 ... Atomizing gas injection part, 2a ... Nozzle for atomizing gas (1st nozzle), 3 ... Reactor, 3a ... Cylindrical Part, 3b ... reduced diameter part (solid gas separator), 3c ... Si particle outlet, 3d ... gas outlet, 5, 8 ... solid gas separator, 10 ... reactor, F ... trickle of molten metal, P ... Molten metal microdroplet, G ... atomized gas.

Claims (10)

A pressurizing step of pressurizing the liquefied tetrachlorosilane;
A heating step of heating the liquefied tetrachlorosilane pressurized in the pressurizing step into a gas or a supercritical fluid;
A process for producing a tetrachlorosilane fluid, comprising:   The method for producing a tetrachlorosilane fluid according to claim 1, wherein the tetrachlorosilane fluid obtained through the heating step has a pressure of 0.1 to 15 MPa and a temperature of 200 to 1200 ° C. An atomizing process comprising supplying a tetrachlorosilane fluid produced by the method according to claim 1 or 2 to a first nozzle and directing the tetrachlorosilane from the first nozzle toward a molten metal discharged from the second nozzle. Comprising an atomizing step of forming fine droplets of the molten metal by injecting a gas;
In the atomizing step, silicon particles are obtained by reducing tetrachlorosilane to obtain silicon particles by bringing the microdroplets into contact with tetrachlorosilane.   The method for producing silicon particles according to claim 3, wherein the atomized gas has a tetrachlorosilane concentration of 10% by volume or more.   The said atomizing gas consists only of the said tetrachlorosilane fluid, The manufacturing method of the silicon particle of Claim 3 characterized by the above-mentioned.   The method for producing silicon particles according to claim 3, wherein the atomizing gas is a mixed gas of the tetrachlorosilane fluid and an inert gas.   The method for producing silicon particles according to claim 6, wherein the inert gas is argon and / or helium.   The molten metal contains one or more kinds selected from the group consisting of Na, K, Mg, Ca, Zn, and Al alone or in combination of two or more kinds. The manufacturing method of the silicon particle of description.   The said molten metal is Al, The manufacturing method of the silicon particle as described in any one of Claims 3-7 characterized by the above-mentioned.   10. The method for producing silicon particles according to claim 3, wherein in the atomizing step, the atomizing gas is injected toward the molten metal at a pressure of 0.1 to 15 MPa.

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