JP2009091195A - Apparatus and method for producing silicon monoxide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for producing silicon monoxide which can stably and efficiently produce highly pure silicon monoxide, and can be easily expanded to cope with the production on an industrial scale. <P>SOLUTION: This production apparatus of silicon monoxide is used for the production of silicon monoxide comprising heating a mixed raw material powder comprising silicon dioxide powder at a temperature range of 1,100-1,600°C under an inert gas atmosphere or a reduced pressure, to generate silicon monoxide gas, and depositing the silicon monoxide gas on the surface of a substrate held at 1,000°C or lower, where the structural member (except the substrate for deposition) in contact with the silicon monoxide gas heated at 1,100-1,600°C is constructed with a C/C composite material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an apparatus and a method for producing silicon monoxide which are suitably used for packaging film deposition and as a negative electrode active material for lithium ion secondary batteries.

  Conventionally, as a method for producing silicon monoxide, silicon and quartz powder are heated and held in vacuum at 1,300 ° C. to generate a gas of silicon monoxide, and the gas of silicon monoxide is heated to 450 to 950 ° C. A method of depositing on a held vapor deposition tube (Patent Document 1: Japanese Patent Publication No. 40-22050), a raw material mixture made of silicon dioxide-based oxide powder is heat-treated in a reduced pressure non-oxidizing atmosphere to generate silicon monoxide vapor. , A method of continuously producing a fine amorphous silicon monoxide powder of 0.1 μm or less by condensing this silicon monoxide vapor in a gas phase (Patent Document 2: JP-A 63-103815), And a method of evaporating raw material silicon by heating and evaporating it on the surface of a substrate having a rough surface structure (Patent Document 3: Japanese Patent Application Laid-Open No. 9-110212) is known. On the way It has been produced. In this case, the generated silicon monoxide vapor is very active and highly reactive, and it is difficult to select a furnace component that contacts the silicon monoxide vapor. None of the components were touching the material.

  Therefore, the present inventors pay attention to this problem, and heat the mixed raw material powder containing at least silicon dioxide powder at a temperature range of 1,100 to 1,600 ° C. under an inert gas or a reduced pressure to produce silicon monoxide gas. In the method for producing silicon monoxide powder in which the silicon monoxide gas is deposited on the cooled substrate surface, at least one of the reaction chamber, the transfer pipe, and the heater, which are furnace components, is Mo, W and / or their An invention formed by a graphite material in which graphite is coated with a high melting point metal such as a compound or a silicon carbide film has been proposed (Patent Document 4: Japanese Patent Application Laid-Open No. 2001-220124), enabling stable production of silicon monoxide.

  However, the method described in JP-A-2001-220124 uses a refractory metal such as Mo or W, although the damage is significantly reduced as compared with a method using a graphite material as a conventional furnace component. In such a case, there is a problem that it is expensive and it is difficult to process a predetermined shape. In addition, even when using a graphite material with graphite coated with a silicon carbide film, if the silicon carbide film is accidentally peeled off, damage may occur starting from the exposed graphite material. It was not the way to go.

  On the other hand, in a general silicon monoxide production apparatus, graphite is used as a furnace constituent member, and the generated silicon monoxide vapor and the composed graphite member undergo a reaction according to the following reaction formula.

C (s) + SiO (g) → SiC (s) + CO (g)
As a result of such a reaction, the silicon monoxide production apparatus described above suffers strength deterioration due to exhaustion of the graphite material, and internal residual strain due to the difference in thermal expansion between the silicon carbide and the graphite material that are heterogeneously formed inside the graphite material. For this reason, there is a problem that the graphite member, that is, the reaction chamber composed of the raw material container and the muffle, the transfer tube, and the heater are damaged, and cannot be operated for a long time.

Japanese Patent Publication No. 40-22050 JP-A 63-103815 JP-A-9-110412 JP 2001-220124 A

  The present invention has been made in view of the above circumstances, and is capable of producing silicon monoxide stably and efficiently even when used in a silicon monoxide vapor atmosphere and capable of increasing the size. And it aims at providing a manufacturing method.

  In order to achieve the above object, the present inventors conducted a high temperature test on various high temperature members in a silicon monoxide vapor atmosphere using a test piece, and as a result, silicon monoxide was obtained by using a C / C composite material. Knowledge that it can sufficiently withstand use in steam can be obtained, and silicon monoxide can be stably produced by using a C / C composite material as a constituent member of a production apparatus for silicon monoxide. As a result, the present invention has been completed.

Therefore, this invention provides the manufacturing apparatus and manufacturing method of the following silicon monoxide.
(1) A mixed raw material powder containing at least silicon dioxide powder is heated at 1,100 to 1,600 ° C. under an inert gas or under reduced pressure to generate silicon monoxide gas. In a silicon monoxide production apparatus used in a method for producing silicon monoxide to be deposited on a substrate surface of 000 ° C. or lower, a component in contact with silicon monoxide gas at 1,100 to 1,600 ° C. Is made of a C / C composite material.
(2) The apparatus for producing silicon monoxide according to (1), wherein the C / C composite material is a mixture of graphite powder and graphite fiber, and the mixing ratio of the graphite fiber is 20 to 70% by mass.
(3) The mixed raw material powder containing at least silicon dioxide powder is heated in an inert gas or under a reduced pressure at a temperature range of 1,100 to 1,600 ° C. to generate silicon monoxide gas. In the manufacturing method of the silicon monoxide deposited on the base-material surface below 000 degreeC, it manufactures using the manufacturing apparatus of (1) or (2), The manufacturing method of the silicon monoxide characterized by the above-mentioned.

  According to the silicon monoxide production apparatus of the present invention, high-purity silicon monoxide can be produced efficiently and stably, and it is easy to increase the size, which is sufficient for industrial scale production. It can be answered.

  FIG. 1 shows an apparatus for producing silicon monoxide according to an embodiment of the present invention, in which 1 is a reaction apparatus, and a muffle (protective container) 2 is disposed in the reaction apparatus 1. The inside of the muffle 2 is configured as a reaction chamber 2a, and further, a raw material container 3 is disposed in the muffle 2 (that is, in the reaction chamber 2a), and silicon dioxide powder and this are used as the raw material 4 in the container 3. Contains a mixture with the powder to be reduced. In this case, the reducing powder includes metallic silicon powder, carbon powder, and the like, and those using metallic silicon powder are particularly effective in that <1> increase the reactivity and <2> increase the yield. Yes, preferably used. The mixing ratio of the silicon dioxide powder and the reduced powder is not particularly limited, but usually the molar ratio of the reduced powder to the silicon dioxide powder is 1 <(reduced powder / silicon dioxide powder) <1.3 (molar ratio), particularly 1. .05 ≦ (reduced powder / silicon dioxide powder) ≦ 1.2 (molar ratio), and further preferably about 1.05 <(reduced powder / silicon dioxide powder) <1.2 (molar ratio).

On the outside of the muffle 2, a heater 5 is provided surrounding the muffle 2 in the reactor 1, and a heat insulating material 6 is further provided surrounding the heater 5. The reaction chamber 2a is heated and maintained at a temperature of 1,100 to 1,600 ° C, preferably 1,200 to 1,500 ° C. If the reaction temperature is less than 1,100 ° C., the reaction is difficult to proceed and the productivity is reduced. Conversely, if the reaction temperature exceeds 1,600 ° C., the mixed raw material powder is melted, and the reactivity is reduced. This may make it difficult to select furnace materials.
By the heating, silicon dioxide in the raw material mixture is reduced by the reducing powder to generate silicon monoxide gas at 1,100 to 1,600 ° C., preferably 1,200 to 1,500 ° C.

  The atmosphere in the furnace is an inert gas or under reduced pressure. However, it is desirable to perform under reduced pressure because thermoreactive under reduced pressure has higher reactivity and enables low-temperature reaction. The degree of vacuum is preferably in the range of 1 to 3,000 Pa, particularly 5 to 1,000 Pa. In order to reduce the degree of decompression to less than 1 Pa, the capacity of the vacuum pump must be greatly increased, and the equipment cost increases. On the other hand, the effect of improving the reactivity is negligible. It drops significantly.

  The upper end of the muffle 2 is opened, a gas transport pipe 7 is connected to the opening, and a silicon monoxide deposition vessel (precipitation base) 8 is connected to the gas transport pipe 7. The silicon monoxide deposition zone 8a is configured, and the inner wall surface of the deposition base 8 is a silicon monoxide deposition portion 9.

The silicon monoxide gas generated in the reaction chamber 2a passes through the gas transport pipe 7, flows into the deposition zone 8a, and the deposition substrate 8 in the deposition zone 8a installed in a temperature range of 1,000 ° C. or lower. Then, it is cooled and deposited on the precipitation portion 9. Here, the type and material of the precipitation base 8 are not particularly limited and are not particularly limited as long as they can withstand a temperature of 1,000 ° C., but refractory metals such as SUS, molybdenum, and tungsten are preferable in terms of workability. Used. The precipitation zone 8a is preferably set to a temperature range of 1,000 ° C. or less, usually 700 to 1,000 ° C., particularly 800 to 950 ° C., and the temperature of the precipitation zone 8a is less than 700 ° C. In the case where the solid silicon monoxide (particles) produced has a high BET specific surface area, oxidation may occur at the time of extraction, and the purity of silicon monoxide may be reduced (that is, the SiO ₂ component may be mixed). When the temperature of the precipitation zone 8a exceeds 1,000 ° C., it is difficult to select the material of the precipitation base 8 except for the C / C composite material.

  Reference numeral 10 denotes a vacuum pump. Since the exhaust pipe 11 connected to the vacuum pump 10 communicates with the deposition zone 8a, the vacuum pump 10 is operated so that the inside of the deposition zone 8a and the gas transport pipe 7 The reaction chamber 2a is depressurized so as to have a predetermined depressurization degree.

Here, in the present invention, there is a possibility of contact with at least 1,100 to 1,600 ° C. silicon monoxide gas such as the raw material container 3, the muffle 2, the gas transport pipe 7, and the heater when the muffle is not installed. A furnace constituent member having a C / C composite material is used. In the embodiment shown in FIG. 1, the heater 5 and the heat insulating material 6 are shielded and protected from the silicon monoxide vapor by the muffle 2, so that it is not necessary to form these members with a C / C composite material. . In addition, the deposition base 8 in the temperature range of 1,000 ° C. or less is not necessarily formed of the C / C composite material.
Here, the C / C composite material is not particularly limited, and a material formed of graphite powder and graphite fiber is used.

By using the above-mentioned furnace constituent member as a C / C composite material, the following reaction occurs with the generated silicon monoxide gas as in the case of the graphite material.
C (s) + SiO (g) → SiC (s) + CO (g)
That is, the C / C composite material is converted to the SiC / SiC composite material, but unlike the silicon carbide conversion of the graphite material, the presence of graphite fibers improves the brittleness, and the graphite and silicon carbide. Since the stress due to the difference in thermal expansion is relaxed, the shape can be maintained even when the above reaction occurs.

  Here, the mixing ratio of the graphite powder and the graphite fiber is not particularly limited, but the mixing ratio of the graphite fiber is preferably 20 to 70 mass%, particularly preferably 35 to 60 mass%. If the mixing ratio of the graphite fiber is less than 20% by mass, the silicon carbide produced by the reaction with the silicon monoxide gas may be broken due to the stress due to the difference in thermal expansion coefficient between the base graphite and the graphite. When the mixing ratio of the fibers is more than 70% by mass, the shape of the C / C composite material may not be maintained, and as a result, damage may be caused.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited to the following Example.

[Example]
Silicon monoxide was manufactured using the apparatus shown in FIG. Here, the C / C composite material (graphite powder / graphite fiber = 45/55 (mass ratio)) was used for the raw material container 3, the muffle 2, and the gas transport pipe 7. As raw materials, an equimolar molar mixed powder of silicon dioxide powder and metal silicon powder was used, and 20 kg was charged in a reactor having a muffle 2 volume of 0.5 m ³ . Next, after reducing the pressure in the furnace to 100 Pa or less using the vacuum pump 10, the heater 5 was energized, and the temperature was raised and maintained at a temperature of 1,400 ° C. The generated silicon monoxide gas is installed in the upper part and deposited in the deposition zone 8a set at 850 ° C. The inner surface of the precipitation zone 8a becomes the precipitation base 8 itself, and the material is SUS. After the above operation was performed for 5 hours, cooling was started. After cooling was completed, the precipitate deposited on the surface of the deposition base on the inner surface of the deposition zone 8a was collected and the state inside the furnace was observed. The obtained silicon monoxide was an amorphous powder having a BET of 5 m ² / g and a purity of 99.9% or more, and about 16 kg was recovered. In addition, although the C / C composite material was slightly discolored in green in the in-apparatus observation, it was confirmed that there was no particular problem such as breakage, and after that, operation was performed for 30 batches or more, but no change was observed. .

[Comparative example]
Silicon monoxide was produced under the same conditions as in the Examples except that the raw material container, muffle, and gas transport pipe were made of graphite. The obtained silicon monoxide was an amorphous powder having a BET of 5 m ² / g and a purity of 99.9% or more, as in the Example, and about 16 kg was recovered. On the other hand, in the observation inside the furnace, the graphite surface was partially discolored in green, and then the muffle was damaged at the 15th batch, and the operation had to be stopped. Thereafter, the muffle was replaced and the operation was performed several times. However, in any of the 10th to 30th batches, either the raw material container, the muffle, or the gas transport pipe was damaged, and the subsequent operation was not able to withstand. .

It is a schematic sectional drawing which shows the manufacturing apparatus of the silicon monoxide which concerns on one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reaction apparatus 2 Muffle 2a Reaction chamber 3 Raw material container 4 Raw material 5 Heater 6 Heat insulating material 7 Gas conveyance pipe 8 Deposition container (deposition base)
8a Precipitation zone 9 Precipitation part 10 Vacuum pump 11 Exhaust pipe

Claims (3)

  The mixed raw material powder containing at least silicon dioxide powder is heated in a temperature range of 1,100 to 1,600 ° C. under an inert gas or under reduced pressure to generate silicon monoxide gas, and the silicon monoxide gas is 1,000 ° C. or less. In a silicon monoxide production apparatus used in a method for producing silicon monoxide to be deposited on the surface of the substrate, components contacting silicon monoxide gas at 1,100 to 1600 ° C. (excluding the deposition substrate) Is made of a C / C composite material.   The apparatus for producing silicon monoxide according to claim 1, wherein the C / C composite material is a mixture of graphite powder and graphite fiber, and the mixing ratio of the graphite fiber is 20 to 70 mass%.   The mixed raw material powder containing at least silicon dioxide powder is heated in a temperature range of 1,100 to 1,600 ° C. under an inert gas or under reduced pressure to generate silicon monoxide gas, and the silicon monoxide gas is 1,000 ° C. or less. A method for producing silicon monoxide to be deposited on the surface of the substrate, wherein the production method is performed using the production apparatus according to claim 1 or 2.

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