JP4731818B2 - Method and apparatus for producing high-purity SiO solid - Google Patents

Description

  The present invention relates to a method and an apparatus for producing a high-purity Si solid material, a Si-based ceramics production material, and a high-purity SiO solid used as a raw material for polymer film deposition at low cost and high productivity.

When producing a SiO solid, a combination of Si raw material + SiO ₂ raw material or C raw material + SiO ₂ raw material is often used in powder form (for example, Patent Document 1 and Patent Document 2). High-purity C powder is available relatively easily, but Si and SiO ₂ powders are pulverized from commercially available 50-200 μm diameter powders to increase the efficiency of SiO gas generation. There are methods to be used (Patent Document 3 and Patent Document 4). In this case, since any powder is kneaded due to contamination during the pulverization process, contamination at that time is unavoidable. Furthermore, the smaller the powder diameter of the raw material, the higher the possibility that it will be scattered by the splash phenomenon and mixed into the deposited SiO solid.

  In (Patent Document 5), in order to suppress the raw material mixture into the SiO solid due to the splash phenomenon, a shielding plate that allows only the SiO gas to pass through without passing the raw material scattered at the raw material filling location and the SiO solid deposition location is installed. It is said that it is possible to produce a SiO solid having a metal impurity concentration of 50 ppm or less. However, in this invention, although the raw material Si used is a pulverized semiconductor Si wafer, the Fe concentration in the SiO solid is 8 ppm or more, and the concentrations of several impurity elements are 1 ppm or more. The purity is lower than that of the raw material Si. Also in this case, it is considered that the raw material is contaminated in the process of grinding.

On the other hand, as a method for purifying SiO, for example, there is a method disclosed in (Patent Document 6). This is a method of distilling SiO solid obtained by quenching SiO gas at 1400-1800 ° C. In an apparatus consisting of an evaporation chamber and a collection chamber, when the SiO solid placed in the evaporation chamber is heated to the above temperature and the collection chamber is heated to a reduced pressure state, the SiO gas evaporated in the evaporation chamber is collected in the collection chamber. In this method, impurities that evaporate at the temperature of the evaporation chamber are also introduced into the collection chamber, and actually only 99.9% pure SiO is obtained. It is not done.
JP-A 63-103814 JP-A-4-81524 JP-A-6-57417 JP 2000-262572 A JP 2002-194535 A JP-A-60-215514

As described above, when powder is used as a raw material, the raw material itself may be scattered due to the splash phenomenon and mixed into the SiO solid. Further, in order to increase the reaction rate, a fine powder is used. Then, the possibility becomes higher. SiO ₂ powder, which is one of the raw materials, is inexpensive and high-purity can be obtained relatively easily. However, Si powder may be made of metal Si having a purity of about 98 to 99%. Many. This Si powder contains impurities such as Fe, Al, Cr, Ni, Ca and the like in a mass ratio of several hundred to several thousand ppm. When scattered and mixed in the SiO solid, the concentration of these impurities in the SiO Becomes higher. Even if high-purity Si such as a semiconductor grade is used, the same problem occurs because of the contamination by the pulverization process and the mixing process with the SiO ₂ powder. It is not a raw material suitable for production. High purity C powder is also readily available, but there is a problem that when the splash phenomenon occurs, C itself becomes an impurity in the SiO solid.

  In the method of distilling SiO disclosed in (Patent Document 6), the SiO gas is rapidly cooled to deposit SiO powder, so that impurities in SiO also remain as they are.

In the method of heating the raw material containing SiO ₂ and the raw material containing Si under reduced pressure to generate SiO gas, cooling the SiO gas, and depositing SiO solid, the present invention has no such problems as described above. The present invention provides a method and an apparatus for producing a SiO solid having a high purity and a high production rate.

In the method of heating the raw material containing SiO ₂ and the raw material containing Si under reduced pressure to generate SiO gas, cooling the SiO gas, and precipitating the SiO solid, the SiO solid is generated by the splash phenomenon. In order to prevent contamination, it has been found that it is necessary to use a raw material containing granular SiO _{2 and} to make the raw material temperature equal to or higher than the melting point of Si. Furthermore, as a result of studies to increase the production rate, it has been found that it is effective to maximize the contact area between the melted Si raw material and the SiO ₂ raw material and to fluidize the Si raw material melt.

In the SiO gas generated from the raw material containing impurities, each evaporated impurity element is also contained as a gas. Impurities by limiting the total amount of the raw material containing Si, which is charged into the raw material container, once brought into contact with the raw material containing SiO ₂ to a certain amount, rather than being consumed by SiO vaporization. It was found that element vaporization can be suppressed. Furthermore, even if the impurity element gas comes into the container for depositing SiO, if the deposition temperature of the SiO solid is set to 450 ° C. or higher, the adhesion rate of the impurity gas to the SiO solid surface is reduced and mixed into the SiO solid. It turned out to be difficult.

The present invention is a method for producing a SiO solid by heating a raw material containing SiO ₂ and a raw material containing Si under reduced pressure, generating SiO gas, cooling the SiO gas, and precipitating the SiO solid. A raw material containing SiO ₂ in a reaction raw material container, and a method for producing an SiO solid characterized by heating after placing the raw material containing Si above the raw material containing SiO ₂ , In particular, the raw material containing SiO ₂ in the reaction raw material container is the lower layer, the raw material containing Si is the upper layer, and the method for producing the SiO solid is heated after being laminated, and the raw material containing Si is heated to the melt state. The present invention relates to a method for producing a SiO solid that is reacted with a raw material containing SiO ₂ .

In the production method of the present invention, the raw material containing SiO ₂ is selected to have a particle size range of 0.5 to 100 mm, and the raw material is heated to 1420 to 1800 ° C. At this time, the raw material containing Si is SiO _2. It is desirable that it is fluidized during the contact reaction with the raw material containing. Regarding the amount of raw material used, in the contact reaction between the raw material containing Si and the raw material containing SiO ₂ , at least 5% by mass of the input amount of the raw material containing Si is discharged out of the reaction system as a reaction residue. Regarding the solid deposition of SiO, the temperature is preferably 450 to 1000 ° C.

Further, the present invention provides a method for producing a SiO solid by heating a raw material containing SiO ₂ and a raw material containing Si under reduced pressure, generating SiO gas, cooling the SiO gas, and precipitating the SiO solid. An apparatus to be used, a reaction material container containing a raw material containing Si and a raw material containing SiO ₂ in a vacuum container equipped with a vacuum pump, and a raw material containing Si on the upper part of the raw material containing SiO ₂ in the container the Si raw material container housing disposed a heating means of the reaction raw material vessel, SiO solid production apparatus including a SiO deposit part of the SiO gas is cooled and solidified to produce a raw material containing a raw material and SiO ₂ containing S i, About.

Furthermore, it is desirable to provide a flow means for the raw material containing Si in the Si raw material container. Or, and heating means of the container, it is desirable that means for moving the raw material containing Si from the Si raw material container containing a raw material containing Si to reactant vessel containing a raw material containing SiO ₂ is provided.

Furthermore, the prior SL production equipment, it is desirable to provide a reaction residue separating means and reaction residues recovery means.

  According to the method and apparatus for producing a SiO solid of the present invention, there is no impurity contamination to the SiO solid produced when using a powder raw material, and a high-purity SiO solid is produced even if a raw material having a high impurity concentration is used. This eliminates the need to use expensive high-purity raw materials, eliminates pulverization, kneading, and granulation processes, and provides a high production rate of SiO solids, providing high-purity SiO solids at low cost. can do.

In a method of heating a raw material containing SiO ₂ and a raw material containing Si under reduced pressure to generate SiO gas, cooling the SiO gas, and depositing an SiO solid, the raw material containing SiO ₂ is contained in a reaction raw material container. accommodated, it is heated by placing a raw material containing the Si at the top of the raw material containing the SiO _2. Desirable methods include laminating a raw material containing SiO ₂ in a reaction raw material container as a lower layer, and laminating the raw material containing Si as an upper layer, and then heating or heating the raw material containing Si to a melt state and then adding SiO ₂ . It is made to contact with the raw material to be reacted.

The SiO gas generated from the raw material containing impurities is contained as a gas corresponding to the vapor pressure of each impurity element, and the pressure ratio is
α = ΣP _i / P _SiO (1)
(Where α is the ratio of the total vapor pressure of each impurity element to the SiO gas pressure, P _i is the vapor pressure of each impurity element, and P _SiO is the pressure of the SiO gas)
It becomes. When a raw material having the same impurity concentration is heated at the same temperature, the vapor pressure of each impurity element is constant, so the pressure of the SiO gas generated by the reaction of the raw material is increased, that is, the SiO gas is efficiently generated. As a result, the α is reduced, so that the concentration of impurities adhering to and mixed in the SiO solid can be reduced.

In order to generate SiO gas efficiently, it is necessary to increase the contact area between the Si raw material and the SiO ₂ raw material. However, when a granular SiO ₂ raw material is used and an SiO ₂ raw material is laminated on the upper layer and an Si raw material is stacked on the lower layer and filled in the reaction raw material container, the raw material is heated to dissolve and melt the Si raw material. Since the fluidity of the SiO ₂ raw material is poor and does not move into the Si raw material melt, there is very little SiO ₂ raw material in contact with the Si melt. In addition, when Si raw material and SiO ₂ raw material are mixed and filled, when Si of a small size such as powder is used as the raw material, the Si raw material is formed into droplets and is carried in the SiO ₂ raw material in isolation. There is a possibility, and when the Si raw material in the form of droplets disappears due to the reaction, all of the impurity elements contained therein will be vaporized except those that become solid, so the pressure of the impurity element gas will be high. End up. On the contrary, when Si of a large size is used as the raw material, the portion where the Si raw material is melted and becomes a void is difficult to enter the SiO ₂ raw material, so that the void remains and the contact area between the Si raw material and the SiO ₂ raw material is reduced. Can't be maximized.

On the other hand, when the Si raw material is laminated on the upper layer and the SiO ₂ raw material is stacked on the lower layer and filled in the reaction raw material container, the SiO ₂ raw material is packed most closely, and the melted Si raw material is converted into the lower SiO ₂ raw material by gravity. Since it flows in and fills the gap, the contact area between the Si raw material and the SiO ₂ raw material can be maximized. Alternatively, the reaction raw material container may be filled with only the SiO ₂ raw material in advance and heated, and a melt of Si raw material dissolved in another container may be poured into the reaction raw material container.

By the way, when a powder raw material is used, the bulk density of the raw material is high and the gas permeability of SiO gas is poor. Further, generally the molar ratio of Si and SiO ₂ 1 (mass ratio _{Si: SiO 2 = 28: 60} ) is often to an extent, because there is no true density difference, SiO ₂ has large capacity, thermal conductivity Is bad. Therefore, when the inside of the raw material filled in the reaction raw material container is rapidly heated and SiO gas is generated, the raw material deposited on the upper part of the raw material bumps without being able to withstand the pressure of the SiO gas. Since the powder diameter of the raw material is small and light, the bumped raw material rides on the SiO gas stream and adheres to and mixes with the cooled and solidified SiO solid.

If the particle size of the SiO ₂ raw material is 0.5 mm or more, even if SiO gas is rapidly generated inside the raw material, since the air permeability is ensured, the raw material does not bump. On the other hand, when the particle size is 100 mm or more, the contact area with the melt of the Si raw material becomes small, so that the production rate decreases.

Since the raw material containing SiO ₂ is large, if the Si raw material remains solid, the contact area with the SiO ₂ raw material is extremely small, so the reaction rate is low, the raw material temperature is set to 1420 ° C. or higher, and the Si raw material is dissolved. It is necessary to. In addition, since there is no furnace material that can ensure durability in an environment where Si or SiO exists above 1800 ° C., SiO gas is generated below this temperature.

  The heat of formation of SiO gas is as large as 360 kJ / mol. However, as described above, when a powder raw material is used, since the thermal conductivity is small, the raw material temperature is lowered. In the present invention, since the Si raw material is melted, this is advantageous in that it becomes a heat medium and the raw material can be efficiently heated. Furthermore, by causing the melt of Si raw material to flow and generating forced convection, the heat taken away by the generation of SiO gas can be compensated more efficiently, leading to an improvement in production speed. Here, the melt of the Si raw material is made to flow by dropping or pouring the melt from the upper part of the raw material, mechanical stirring and stirring by electromagnetic induction, or a combination of a plurality of methods.

  Each impurity element is contained as a gas corresponding to the vapor pressure in the SiO gas generated from the raw material containing impurities. When an alloy of Si and impurities is dissolved, the vapor pressure of the impurities is a value determined by multiplying the coefficient determined by the interaction with Si by the equilibrium vapor pressure of the impurity alone and the mole fraction of impurities contained in Si. It becomes.

P = Σk _n · P _n · N _n (2)
(Wherein, P is made the vapor pressure in the system of impurities, k _n is 1 when the coefficient (ideal solution determined by the interaction between the Si and the impurity n), P _n is the impurity n single equilibrium vapor pressure, N _n is the molar fraction of impurity n)
When the impurity concentration is very small, since the impurity is surrounded by Si atoms and receives a uniform interaction from the surroundings, k _n = 1 is not established. For example, in the case of Fe in Si, (2 ) In which k _Fe <1 and the vapor pressure is known to be lower. That is, since Fe in Si is difficult to evaporate, Fe is concentrated when Si is consumed and reduced by the generation of SiO gas.

It is known that when the Si melt and SiO ₂ are brought into contact with each other, SiO ₂ is decomposed and oxygen atoms are dissolved in the Si melt, and an impurity element that is more easily oxidized than Si is changed into an oxide. For example, Ca is an element with a high vapor pressure, but CaO, which is an oxide, has a low vapor pressure, and therefore remains in the Si melt.

When Si raw material powder is used as a raw material, there is Si powder that is consumed by generation of SiO gas and completely disappears at a certain rate. In this case, impurities contained in the Si powder are vaporized except for those remaining as solids in the reaction raw material container, and since the impurities are concentrated just before the Si powder disappears, its vapor pressure is high. The impurity gas concentration in the SiO gas becomes high. On the other hand, when the Si raw material melt is used, it is possible to keep the impurity element which is difficult to evaporate or the element whose oxide has a low vapor pressure in the raw material. However, since the amount of Si raw material melt decreases due to the generation of SiO gas, impurities are concentrated. Therefore, before the reduction amount of the Si raw material melt that is once introduced into the reaction raw material container and contributes to the generation of SiO gas reaches 95%, that is, at least 5 mass% of the input amount of the Si raw material is used as a reaction residue. Since the impurities remaining concentrated are also discharged out of the system, impurity contamination of the generated SiO solid can be prevented. The reaction residue of the Si raw material is prepared by, for example, opening a pore in the bottom of the reaction raw material container in advance, and the Si melt is moved to another container. The moved residue is solidified by being kept at a temperature lower than the melting point of Si so that the impurity element is not vaporized. The container for storing the residue is desirably installed in an area where SiO gas does not flow and can be evacuated independently. In this case, the residue may be stored in the container as a melt without solidifying the residue.

  When the reaction residue is not discharged out of the system, the Si raw material is cooled and solidified at least 5% by mass or less of the input amount of the Si raw material, and generation of SiO gas is stopped, or a new Si raw material is input. Then, a treatment for diluting the impurity concentration may be performed.

  However, as long as impurities are present in the raw material, it is impossible to prevent generation of impurity gas at all. For example, when SiO powder is produced by adiabatic expansion of SiO gas and rapid cooling, most of the impurities other than impurities having a very high vapor pressure are trapped in the SiO powder even at a low temperature. become. Therefore, the present inventors investigated the deposition temperature dependence of the impurity concentration in the SiO solid for each of several types of impurity elements. B, Fe, Ni, Cr, etc. are temperature dependent on the adhesion coefficient to the SiO solid surface. It has been found that if the deposition temperature is 450 ° C. or higher, it can be sufficiently removed from the SiO solid. However, if the precipitation temperature is too high, the precipitation rate of the SiO solid itself decreases, so the upper limit was set to 1000 ° C.

In order to enable the production of the SiO solid by the above-described method, the first apparatus heats the raw material containing SiO ₂ and the raw material containing Si under reduced pressure to generate SiO gas, cool the SiO gas, An apparatus used in a method for producing a SiO solid by precipitating a solid, a reaction raw material container containing a raw material containing Si and a raw material containing SiO ₂ in a decompression vessel equipped with a vacuum pump, and in the vessel An Si raw material container for containing a raw material containing Si is arranged on the upper part of the raw material containing SiO _2, and the heating means of the reaction raw material containing container, and the SiO gas generated from the raw material containing Si and the raw material containing SiO ₂ are cooled and solidified. An SiO solid production apparatus comprising at least a SiO depositing portion. The second apparatus includes a reaction raw material container that contains a raw material containing Si and a raw material containing SiO ₂ in a vacuum container equipped with a vacuum pump, a heating means for the container, and a flow of the raw material containing Si in the container. An apparatus for producing an SiO solid, comprising at least means, and an SiO precipitation portion for cooling and solidifying SiO gas generated from a raw material containing Si and a raw material containing SiO ₂ . A vacuum pump is selected that has the ability to depressurize the inside of the container at least below the vapor pressure of SiO, and is equipped with a heater that can heat the Si and SiO ₂ raw materials to over 1420 ° C. Any one or more of a pouring device, a device capable of mechanically stirring the melt, and a device capable of stirring by electromagnetic induction are installed. The SiO precipitation part that solidifies the SiO gas can be controlled in the range of 450 to 1000 ° C., and the space in which the SiO gas moves from the raw material part to the precipitation part can be set to at least 1300 ° C. at which SiO does not solidify. It can be done.

In addition, the space where the SiO gas exists from the reaction raw material container containing the raw material containing Si and the raw material containing SiO ₂ to the SiO precipitation portion in a vacuum container equipped with a vacuum pump is in contact with the heating means. Not covered with walls. The reaction raw material container is placed on a raw material container rotating device installed in the lower part of the decompression container, and the flow means of the raw material containing Si in the reaction raw material container is a mechanical stirring means by rotation, And a stirring means by electromagnetic induction. The SiO depositing part is installed in the upper part of the decompression device and connected through a branch pipe for introducing SiO gas. The branch pipe is also provided with a heating means capable of heating to at least 1300 ° C. or higher. The SiO deposited portion must be able to be maintained at 450 to 1000 ° C. If it is possible to insulate the SiO deposited portion and heat to the temperature range by heat conduction or radiation from the heated branch pipe, a heat insulating material may be installed on the outer periphery of the SiO deposited portion. If this is impossible, it is necessary to provide heating means.

The third apparatus stores a Si raw material container containing a raw material containing Si , a heating means for the container, a reaction raw material container containing a raw material containing SiO ₂ , a heating means for the container, and a raw material containing Si. This is an apparatus that can move a raw material containing Si, if necessary, from a raw material vessel of Si to a reaction raw material vessel containing a raw material containing SiO ₂ . A Si raw material container for containing the Si raw material and a reaction raw material container for containing the SiO ₂ raw material are disposed separately, and each is provided with a heater that can be heated to over 1420 ° C. The Si raw material container for storing the Si raw material is equipped with a device capable of pouring Si melt, or when the Si itself melts in the container itself, the melt automatically flows into the reaction raw material container for storing the SiO ₂ raw material. It has a function to do. That is, the Si raw material container that contains the raw material containing Si is a melted droplet lower container such as a funnel with a scale plate (when the particle size is small), and when the raw material melts, it automatically drops through the scale plate. The reaction raw material container for containing the raw material containing SiO ₂ needs to have a capacity not only for containing SiO ₂ but also for containing the falling Si melt. Therefore, Si raw material container containing a material containing Si is located above the reactant vessel containing a raw material containing SiO _2, and the Si melt reactant vessel containing a raw material containing SiO ₂ is falling It must be in a position where it can be received. The decompression vessel and the SiO depositing part are the same as in the case of the first invention.

In the fourth apparatus, a Si residue is collected from the reaction raw material container in any one of the first apparatus to the third apparatus, and a container for storing it is installed. The reaction raw material container is provided with a tilting device, or the bottom of the reaction raw material container has a pore, and has a function of automatically flowing into the Si residue collection container. The Si residue recovery container can maintain a temperature below the Si melting point even when the reaction raw material container is heated to a predetermined temperature for generating SiO gas. Furthermore, in the area where the container for storing the residue is installed, SiO gas does not flow in, and can be exhausted independently.

Example 1
FIG. 1 is an example of an apparatus for carrying out the present invention. A Si raw material container 15 in which 1.2 kg of 3 to 7 mm silica stone particles 13 is filled in a carbon reaction raw material container 12 having a diameter of 120 mm and a depth of 300 mm, and 0.6 kg of metal Si particles of 10 to 50 mm are placed thereon. Was placed in the lower raw material chamber 4 made of carbon. The impurity concentration of each raw material is as shown in Table 1. A heat insulating material 11 is attached to a 500 mm-long quartz precipitation vessel 6 having a diameter of 100 mm at the junction side opening between the upper part of the raw material chamber 1 and the deposition chamber 2 and a diameter of 50 mm at the other end. 2 installed. First, after evacuating the inside of the vacuum vessel provided with the raw material chamber 1 and the deposition chamber 2 from the exhaust port 3 with the vacuum pump until the pressure becomes 1 Pa or less, Ar is introduced, and the atmospheric pressure in the chamber Then, the heating of the heaters 7, 8, and 9 was started. The temperature distribution in the deposition vessel 6 was controlled to 650 to 800 ° C. by the heater 9, and at this time, the temperatures of the lower raw material chamber 4 and the upper raw material chamber 5 were controlled to 1450 ° C. by the heaters 7 and 8. The metal Si raw material deposited in the upper part of the reaction raw material container 12 is dissolved, and the Si raw material melt enters the gaps between the quartzite grains 13. Thereafter, the inside of the chamber was evacuated by a vacuum pump, and the temperature was raised until the lower raw material chamber 4 and the upper raw material chamber 5 reached 1650 ° C. At this time, the reaction material container 12 was rotated at 50 rotations / minute for 1 minute by the material rotation device 16, and then a cycle of stopping for 1 minute was repeated. The Si raw material melt flows, and a reaction between the Si raw material melt and the silica particles generates SiO gas, which is sent to the precipitation vessel 6 via the carbon branch pipe 10, where the SiO solid is precipitated. . SiO gas was generated until the remaining amount of the Si raw material melt reached 0.1 kg, the power output of the heater 7 was turned off, and the lowering of the temperature of the lower raw material chamber 4 was started. At this time, the upper raw material chamber 5 was kept at 1650 ° C., and the precipitation vessel 6 was kept at a temperature range of 650 to 800 ° C. When the lower raw material chamber 4 became 1300 ° C. or lower, the power output of the heaters 8 and 9 was turned off. The production rate of SiO in this example was 38 kg / m ² / hr, and the impurity concentration of the obtained SiO was as shown in Table 1.

(Example 2)
The present invention was implemented with the apparatus of FIG. A carbon Si raw material melt dropping container 17 having a nozzle inner diameter of 5 mm and a length of 200 mm was charged with 1.0 kg of 10-50 mm metal Si particles and placed in the upper raw material chamber 5. A carbon reaction raw material container 12 having a diameter of 120 mm and a depth of 300 mm was filled with 3.0 kg of 3 to 7 mm of silica stone particles 13 and installed in the lower raw material chamber 4. A nozzle having a length of 50 mm and an inner diameter of 1 mm was provided at the bottom of the reaction raw material container 12. A carbon Si melt tray 21 having a diameter of 120 mm and a depth of 100 mm was installed in the Si raw material residue chamber 18 provided with the exhaust port 19. Each raw material was the same as that used in Example 1. A heat insulating material 11 is attached to a 500 mm-long quartz precipitation vessel 6 having a diameter of 100 mm at the junction side opening between the upper part of the raw material chamber 1 and the deposition chamber 2 and a diameter of 50 mm at the other end. 2 installed. First, the inside of the vacuum vessel provided with the raw material chamber 1 and the deposition chamber 2 is evacuated by a vacuum pump from the exhaust port 3 until the pressure becomes 1 Pa or less, and the heating of the heaters 7, 8 and 9 is started. did. The temperature distribution in the precipitation vessel 6 is controlled to 650 to 800 ° C. by the heater 9, and at this time, the temperatures of the lower raw material chamber 4 and the upper raw material chamber 5 are controlled to 1400 ° C. by the heaters 7 and 8. . Thereafter, the lower raw material chamber 4 and the upper raw material chamber 5 were heated to 1650 ° C. The Si raw material 14 charged in the Si raw material melt drop container 17 is melted, and the Si raw material melt 20 flows into the reaction raw material container 12. The Si raw material melt reacts with the silica particles 13 to generate SiO gas, which is fed into the deposition vessel 6 through the carbon branch pipe 10, where SiO solids are deposited. Further, since the reaction raw material container 12 is also provided with a through hole, the melt is gradually dropped onto the Si melt receiving tray 21. Thereby, the Si raw material melt 20 in the raw material container 12 flows due to gravity. Further, since the temperature of the Si melt receiving tray 21 is equal to or lower than the Si melting point, impurities are concentrated and the dropped Si melt is solidified. A trace amount of impurity elements that vaporize before solidification is exhausted through the exhaust port 19. When the generation of SiO gas was completed, the power output of the heater 7 was turned off and the temperature of the lower raw material chamber 4 was started to be lowered. At this time, the upper raw material chamber 5 was kept at 1650 ° C., and the precipitation vessel 6 was kept at a temperature range of 650 to 800 ° C. When the lower raw material chamber 4 became 1300 ° C. or lower, the power output of the heaters 8 and 9 was turned off. The production rate of SiO in this example was 72 kg / m ² / hr, and the impurity concentration of the obtained SiO was as shown in Table 1. After the experiment, the amount of Si accumulated in the Si melt tray 21 was measured and found to be 0.3 kg.

(Comparative Example 1)
A comparative experiment was performed with the apparatus of FIG. A carbon reaction raw material container 12 having a diameter of 120 mm and a depth of 300 mm is filled with 1.2 kg of 3 to 7 mm silica stone particles 13 and 0.6 kg of 10 to 50 mm metal Si particles 14 and mixed. The lower raw material chamber 4 was charged. Each raw material was the same as in Example 1. An insulating material 11 is attached to a 500 mm-long quartz deposition container 6 having a diameter of 100 mm at the junction side opening between the upper part of the raw material chamber 1 and the deposition chamber 2 and a diameter of 50 mm at the other end. Installed in chamber 2. First, the inside of the vacuum vessel provided with the raw material chamber 1 and the deposition chamber 2 is evacuated by a vacuum pump from the exhaust port 3 until the pressure becomes 1 Pa or less, and the heating of the heaters 7, 8 and 9 is started. did. The heater 9 controls the temperature distribution in the deposition vessel 6 to be 650 to 800 ° C., and at this time, the temperature of the lower raw material chamber 4 and the upper raw material chamber 5 is controlled to 1400 ° C. by the heaters 7 and 8. did. Thereafter, the temperature of the lower raw material chamber 4 and the upper raw material chamber 5 was increased to 1650 ° C. SiO gas is generated by the reaction between the Si raw material melt and the silica particles, and is sent to the precipitation vessel 6 via the carbon branch pipe 10, where the SiO solid is precipitated. SiO gas was generated until the remaining amount of the Si raw material melt reached 0.1 kg, the power output of the heater 7 was turned off, and the lowering of the temperature of the lower raw material chamber 4 was started. At this time, the upper raw material chamber 5 was kept at 1650 ° C., and the precipitation vessel 6 was kept at a temperature range of 650 to 800 ° C. When the lower raw material chamber 4 became 1300 ° C. or lower, the power output of the heaters 8 and 9 was turned off. The production rate of SiO in this example was 15 kg / m ² / hr, and the impurity concentration of the obtained SiO was as shown in Table 1.

(Comparative Example 2)
Using the same apparatus as in Comparative Example 1, the temperature distribution in the precipitation vessel 6 was changed to 300 to 400 ° C. to produce a SiO solid. The production rate of SiO in this example was 15 kg / m ² / hr, and the impurity concentration of the obtained SiO was as shown in Table 1.

  From the results of Table 1, it was found that the impurity concentration in the SiO solid according to the practice of the present invention was lower than that of the sample of the comparative example. In particular, it has conditions for the precipitation temperature of the SiO solid and the amount of Si residue discharged out of the system, and the Si melt is moved into the silica grain raw material so that the Si melt flows in the silica granule raw material. Thus, the SiO solid produced in Example 2 with the highest production rate of the SiO solid was the highest purity.

It is a conceptual diagram which shows an example of the SiO solid manufacturing apparatus which implements this invention. It is a conceptual diagram of another SiO solid manufacturing apparatus which implements this invention. It is a conceptual diagram of the SiO solid manufacturing apparatus which implements a comparative example.

Explanation of symbols

1 Raw material chamber
2 chamber for deposition chamber,
3 Exhaust port,
4 Lower raw material chamber,
5 Upper material chamber,
6 Precipitator,
7 Heater,
8 Heater,
9 Heater,
10 branch pipes,
11 Insulation,
12 reaction raw material container,
13 Silicate stone,
14 Si raw material,
15 Si raw material container,
16 Raw material container rotating device,
17 Si raw material melt drop container,
18 Si raw material residue chamber,
19 Exhaust port,
20 Si raw material melt,
21 Si melt pan.

Claims (13)

SiO ₂ A raw material containing Si and a raw material containing Si are heated under reduced pressure to generate SiO gas, the SiO gas is cooled, and a SiO solid is precipitated to produce a SiO solid, SiO ₂ Containing raw material containing the SiO 2 ₂ A method for producing an SiO solid, comprising: heating a raw material containing Si, after disposing the raw material containing Si. A raw material containing a raw material and Si containing SiO ₂ was heated under reduced pressure, to generate SiO gas, the SiO gas is cooled to a method of making the SiO solid by precipitating the SiO solid, the reaction raw material container _{2. The} method for producing an SiO solid according to claim 1 , wherein the raw material containing SiO2 is laminated as a lower layer and the raw material containing Si is laminated as an upper layer, followed by heating. A method for producing a SiO solid by heating a raw material containing SiO ₂ and a raw material containing Si under reduced pressure, generating SiO gas, cooling the SiO gas, and precipitating SiO solid, The method for producing an SiO solid according to claim 1, wherein the raw material containing the mixture is heated to a melt state and then brought into contact with the raw material containing SiO ₂ for reaction. The method for producing a SiO solid according to any one of claims 1 to 3, wherein the raw material containing SiO ₂ has a particle size range of 0.5 to 100 mm. SiO solid production method according to any one of claims 1 to 3 for heating a raw material containing the SiO ₂ to 1420-1,800 ° C.. The method for producing a SiO solid according to any one of claims 1 to 3, wherein the raw material containing Si flows during a contact reaction with a raw material containing SiO ₂ . In the contact reaction between the raw materials including a raw material and SiO ₂ containing the Si, according to claim 1 to 3 for discharging at least 5 wt% of the input amount of raw material including Si out of the reaction system as a reaction residue of any one A method for producing a SiO solid. The method for producing an SiO solid according to any one of claims 1 to 3, wherein a temperature at which the SiO is solid-deposited is 450 to 1000 ° C. An apparatus used in a method for producing a SiO solid by heating a raw material containing SiO ₂ and a raw material containing Si under reduced pressure, generating SiO gas, cooling the SiO gas, and precipitating the SiO solid, A reaction raw material container containing a raw material containing Si and a raw material containing SiO ₂ in a vacuum container equipped with a vacuum pump, and an Si raw material container containing a raw material containing Si on the upper part of the raw material containing SiO ₂ in the container arrangement, and the heating means of the reaction raw material vessel, SiO solid production device characterized by at least including a SiO deposit part of cooling and solidifying the SiO gas generated from the raw material containing the raw material and SiO ₂ containing S i. The apparatus for producing a SiO solid according to claim 9, further comprising a raw material flow means containing Si in the reaction raw material container. Manufacturing apparatus according to claim 9, wherein the SiO solid, characterized in that it comprises a heating hand stage of the Si raw material container. SiO solid production apparatus according to claim 11, further comprising a means for moving the raw material containing Si from the Si raw material container into the reaction feedstock vessel containing a raw material containing SiO ₂ containing ingredients comprising the Si. Further, reaction residue separating means and SiO solid production apparatus according to any one of claims 9-1 2 comprising a reaction residue recovery means.

Images