WO2015015795A1 - Siox powder manufacturing process and siox powder manufacturing apparatus - Google Patents

Siox powder manufacturing process and siox powder manufacturing apparatus Download PDF

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Publication number
WO2015015795A1
WO2015015795A1 PCT/JP2014/003961 JP2014003961W WO2015015795A1 WO 2015015795 A1 WO2015015795 A1 WO 2015015795A1 JP 2014003961 W JP2014003961 W JP 2014003961W WO 2015015795 A1 WO2015015795 A1 WO 2015015795A1
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sio
powder
gas
heating furnace
plasma
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PCT/JP2014/003961
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French (fr)
Japanese (ja)
Inventor
滋 中澤
横山　和弘
朗 臼井
鈴木　義之
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東京印刷機材トレーディング株式会社
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Priority to JP2015529389A priority Critical patent/JP6352917B2/en
Publication of WO2015015795A1 publication Critical patent/WO2015015795A1/en

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a method and an apparatus for producing SiO X powder used as a negative electrode active material for a lithium ion secondary battery and a vapor deposition material for a gas barrier film.
  • a lithium ion secondary battery has a positive electrode, a negative electrode, and a separator impregnated with an electrolytic solution between the two electrodes, and is configured such that lithium ions reciprocate between the positive electrode and the negative electrode through the electrolytic solution by charging and discharging. ing.
  • an active material capable of occluding and releasing lithium ions (negative electrode active material) is used, and at present, a carbon-based negative electrode material is common.
  • the improvement in the energy density of the carbon-based negative electrode active material has reached its limit, and various negative electrode active materials have been developed with the aim of further improving the energy density.
  • Si-based negative electrode active materials are attracting attention as very promising materials.
  • the lithium ion storage capacity is about 10 times that of the carbon-based negative electrode active material.
  • Lithium ion storage capacity is lower than that of metal Si, but it is known that it is effective to use SiO as a material in which volume expansion / contraction during charge / discharge is small and charge / discharge cycle characteristics are unlikely to deteriorate.
  • SiO has different lithium ion storage capacity and volume expansion / contraction due to charge / discharge depending on the change of X value of SiO X. Accordingly, there are various means for determining the optimum point, such as the blending ratio with the carbon-based negative electrode active material and the selection of the binder. In conjunction with this, a manufacturing means capable of arbitrarily controlling the X value of SiO X is required. In general, many of the preparation of SiO X, to generate a SiO X gas in a heating furnace, it is precipitated in the precipitation substrate produce SiO X product bulk. This is pulverized and the particle diameter is adjusted to produce a negative electrode active material powder for a lithium ion secondary battery.
  • Patent Document 1 discloses a method for producing silicon monoxide.
  • silicon metal powder is introduced into a plasma jet ejected into an atmospheric gas at a supply rate of 70 g / min or more using a carrier gas.
  • the silicon metal powder not vaporized in the plasma jet is brought into contact with oxygen gas contained in at least one of the carrier gas and the atmospheric gas to cause a synthesis reaction.
  • silicon monoxide vapor is continuously generated while maintaining the reaction frame generated in the synthesis reaction.
  • the crude product obtained by quenching the generated silicon monoxide vapor is distilled at 1,400 ° C. to 1,800 ° C.
  • Patent Document 2 discloses a method for producing SiO x (X ⁇ 1) used as a negative electrode active material for a lithium ion secondary battery and a vapor deposition material for a gas barrier film.
  • a mixed raw material composed of metal Si powder and SiO 2 powder or SiO powder is vaporized by plasma heating to form SiO gas.
  • SiO X (X ⁇ 1) is vaporized by plasma heating to form SiO gas.
  • SiO X (X ⁇ 1) after depositing as silicon oxide SiO X (X ⁇ 1) on the deposition substrate, it was crushed by a ball mill to obtain powdered silicon oxide.
  • the packaging material In the field of processing food packaging, medical products, and pharmaceuticals, the packaging material is required to have high gas barrier properties so that oxygen and moisture do not permeate the packaging material in order to prevent deterioration of the food, pharmaceuticals, and the like.
  • a packaging material having a SiO vapor deposition film having high gas barrier properties and excellent transparency has been attracting attention.
  • food packaging films in which a SiO film is formed on a polymer film are produced. It should be noted that excellent transparency is necessary for observing the package contents from the appearance and confirming alteration and deterioration. In particular, it can be said to be an essential property for packaging materials for packaging foods and the like.
  • Patent Document 1 describes that a metal silicon supply rate of 70 g / min or more and a metal powder particle size of 400 ⁇ m or less (average particle size of 100 ⁇ m) are preferable.
  • silicon metal powder supplied into a plasma jet becomes vapor and reacts with oxygen gas to synthesize silicon monoxide.
  • the temperature in the reaction frame is raised to 3,000 K (2,727 ° C.) or more by heat from the plasma and reaction heat.
  • the speed of a plasma flame of a DC (direct current) plasma jet is as high as 300 m / sec or more.
  • Patent Document 1 describes that the temperature of the plasma flame is increased to 3,000 K (2,727 ° C.) or higher by heat from the plasma flame and reaction heat between the metal Si vapor and oxygen.
  • the heat of vaporization of metal Si is much larger than the heat of reaction, and when the amount of material supply increases, the temperature of the plasma flame rapidly decreases, and there is a problem that a large amount of metal Si that cannot be vaporized remains.
  • the material supply amount and the theoretical oxygen amount were calculated and introduced at the target stoichiometric atomic weight ratio, the temperature was not uniform in the plasma flame and the temperature difference was partially large, so it was introduced and scattered. A uniform oxidation reaction with metal Si does not occur. Therefore, the oxidation reaction proceeds partially, and the ratio of vaporized metal Si to SiO 2 becomes very large.
  • Patent Document 2 a mixed raw material composed of metal Si powder and SiO 2 powder or SiO powder is vaporized by plasma heating to form SiO gas, and then deposited on a deposition substrate as silicon oxide SiO X (X ⁇ 1). It is described.
  • the center temperature of the plasma flame is preferably 5,000 ° C. to 100,000 ° C., more preferably only 10,000 ° C. to 20,000 ° C.
  • Patent Document 2 does not describe what plasma operation conditions, raw material particle diameters, and material supply speeds are used in which plasma apparatus. For example, when an RF (high frequency induction) thermal plasma apparatus is used, the heat capacity of the plasma flame is very small even if the temperature of the plasma flame is an ultrahigh temperature of 10,000 ° C. or higher. Accordingly, some metal Si having a small particle size melt and vaporize, but a large number of ones having a large particle size are spheroidized and solidified as they are, and it is difficult to produce SiO.
  • RF high frequency induction
  • the plasma flame is a very hot gas but has a very small heat capacity, while the heat of vaporization of metal Si is very large. Is because it does not vaporize.
  • the mixed raw material consisting of the metal Si powder and the SiO 2 powder or the SiO powder charged into the plasma flame is scattered in all directions and the vaporization temperature is greatly different, so the mixed particles of the metal Si powder and the SiO 2 powder This is because the synthesis reaction is difficult to occur. That is, a mixed powder of metal Si powder and SiO 2 powder and / or SiO powder is put into a plasma flame at 10,000 ° C. to 20,000 ° C., and all these are completely vaporized to cause SiO X conversion reaction.
  • Patent Document 2 it is insufficient to completely evaporate the mixed powder of the metal Si powder and the SiO 2 powder and / or the SiO powder to cause the SiO X conversion reaction.
  • Patent Document 2 in order to suppress splash, when a raw material that generates SiO gas is heated to a high temperature by a plasma flame, vaporized metallic silicon and oxygen react in an atomic state to generate SiO gas, and this SiO gas It is said that SiO X (X ⁇ 1) obtained by precipitating is effectively distributed uniformly without containing crystalline metallic silicon and silicon dioxide and becomes amorphous. Splash is a phenomenon in which fine particles of metal silicon and silicon dioxide that are not vaporized are scattered together with vaporized SiO gas. If splash is generated when forming the SiO vapor deposition film, fine particles that are not vaporized adhere to the SiO vapor deposition film on the polymer film, causing defects such as pinholes, and gas barrier properties are deteriorated.
  • the metal Si powder and the SiO 2 powder are not vaporized in the plasma flame and become an atomic state, but in most cases, they are not vaporized but remain as droplets. is there. That is, it is important in what kind of particle size powder raw material is heated in which plasma flame (temperature, plasma flame speed) of the plasma apparatus, but this is described in Patent Document 2. Absent. In the case of a temperature of 10,000 ° C. plasma flame of a DC (direct current) plasma spray gun, the average particle size D 50 generally used in the DC (direct current) plasma spray gun is 30 ⁇ m because the speed of the plasma flame is high. Even if a level of metal Si powder is supplied, most of the powder is only partially melted and hardly gasified.
  • the present invention has been made in order to solve the above-described problems, and its purpose is to continuously and inexpensively produce SiO X powder used as a negative electrode active material of a lithium ion secondary battery and a vapor deposition material of a gas barrier film. and to provide a SiO X powder preparation and SiO X powder production apparatus capable of.
  • the SiO X powder production method of the present invention includes a step of heating and melting a mixed granulated powder of metal Si powder and SiO 2 powder with a plasma flame, and vaporizing molten droplets of the heated and melted mixed granulated powder in a heating furnace. And a step of causing the SiO X reaction to be performed, and a step of rapidly cooling the generated SiO X gas with an inert gas to precipitate SiO X fine powder.
  • the SiO X powder production apparatus of the present invention is a mixed granulation of a DC (direct current) plasma apparatus or an RF (high frequency induction) thermal plasma apparatus equipped with a plasma gun for ejecting a plasma flame, and a metal Si powder and SiO 2 powder.
  • Powder supply device for spraying powder into plasma flame, heating furnace for vaporizing molten droplets of mixed granulated powder heated and melted in plasma flame to perform SiO X conversion reaction, and generated SiO X gas
  • a cooling device for precipitating SiO X fine powder by rapid cooling with an inert gas.
  • high purity (4N or more) Si powder is used as a metal Si powder raw material.
  • the high-purity (4N or higher) Si powder is used by regenerating metal Si sludge generated in a silicon wafer manufacturing process such as for semiconductors and solar cells to a high purity (4N or higher).
  • metal Si used for semiconductors, solar cells and the like has been purified to a very high purity.
  • the powder generated in the silicon wafer slicing and polishing process is very difficult to handle with fine particles, collected as sludge contaminated with impurities, and processed as waste as cost.
  • the present invention is a metal Si powder and SiO 2 powder, each having an average particle diameter D 50 of 10 ⁇ m or less, preferably have an average particle diameter D 50 using the following metal Si powder and SiO 2 powder 5 [mu] m, SiO X
  • the mixing ratio of the metal Si powder and the SiO 2 powder is set so that the X value of is 0.5 to 1.8.
  • the present invention water in these mixed powder materials, solvent, dispersing agent, by mixing a binder, well stirred mixture by a mixer, spray drying method obtained by slurrying the average particle diameter D 50 at (spray-dried) It is preferable to use a mixed granulated powder of metal Si powder and SiO 2 powder granulated to 10 ⁇ m to 50 ⁇ m.
  • the metal Si powder and the SiO 2 powder are uniformly mixed and granulated at a constant ratio, and the raw material is used as a secondary raw material.
  • This secondary raw material which is a mixed granulation of metal Si powder and SiO 2 powder, enhances the reactivity between fine powders, and melts the mixed granulated powder of metal Si powder and SiO 2 powder in the plasma flame. It has a great effect on vaporization.
  • the metal Si powder and the SiO 2 powder are present in a certain ratio in the particles of the mixed granulated powder of the metal Si powder and the SiO 2 powder, the X value of the SiO X gas has an extremely stable atomic ratio. Easy to composition.
  • the present invention uses a DC (direct current) plasma device or an RF (radio frequency induction) thermal plasma device as a device for generating a plasma flame, and a metal Si powder and SiO for a plasma flame of 6,000 K (5,727 ° C.) or more.
  • the mixed granulated powder with 2 powders is blown and melted by heating (partially vaporized).
  • a DC (direct current) plasma apparatus is characterized by a high speed flame that is a plasma flame.
  • a DC (direct current) plasma device is a high-adhesion coating film that is made by introducing a high melting point ceramic powder into a Mach 2 level plasma jet such as plasma spraying, instantly melting the material and welding it to the substrate at high speed. Is generally used to form
  • the DC (direct current) plasma apparatus uses the mixed granulated powder of the metal Si powder and the SiO 2 powder as a raw material and heats and melts (partially vaporizes) the mixed granulated powder as in the present invention.
  • the frame speed is too fast.
  • a material having a large heat of fusion and heat of vaporization, such as metal Si is insufficient in terms of heat amount and reaction time for vaporization even if it is melted. Therefore, the DC (direct current) plasma device increases the nozzle diameter at the tip of the plasma gun and makes the material flight speed in the plasma flame 150 m / sec or less, thereby increasing the reaction time and melting and vaporizing. And a special structure that promotes chemical reactions.
  • a heating furnace is installed in front of the plasma gun in order to completely gasify the metal Si that is not vaporized and the SiO 2 powder to cause a synthetic reaction.
  • a graphite heater heating furnace or a high-frequency induction heating furnace is used as the heating furnace, a highly heat-resistant graphite pipe is used as the reaction tube, the periphery of the graphite tube is insulated, and further water-cooled.
  • the droplet melted by the plasma flame is further heated and vaporized while maintaining the temperature in the graphite tube at 2,000 K (1,727 ° C.) or higher, thereby completely generating SiO X gas. That is, all of the droplets melted by the plasma flame are gasified, so that the generated SiO X has a uniform composition.
  • SiO X as SiO X also gas barrier film for vapor deposition material as a negative electrode active material of a lithium ion secondary battery, when without vaporizing unreacted metal Si and SiO 2 remains, deterioration in charge-discharge characteristics of the negative electrode And lead to deterioration of gas barrier properties.
  • a compressed inert gas such as N 2 or Ar is jetted and mixed from the ring-shaped nozzle at the outlet of the heating furnace, and the high-temperature SiO X gas is rapidly cooled to 800 ° C. or less to 0.01 ⁇ m
  • a cooling device for precipitating ⁇ 10 ⁇ m SiO X fine powder is provided.
  • High-temperature SiO X gas of 2,000 K (1,727 ° C.) or more generated in the reaction tube of the heating furnace is N 2 , Ar, or the like ejected from the ring-shaped nozzle of the cooling device provided at the outlet of the heating furnace. by being suddenly cooled to 800 ° C.
  • the inside of the heating furnace is preferably operated under a reduced pressure of 30 kPa to 80 kPa.
  • a reduced pressure of 30 kPa to 80 kPa By operating the inside of the reaction tube of the heating furnace under a reduced pressure of 30 kPa to 80 kPa, the reaction temperature between the metal Si powder and the SiO 2 powder can be lowered and the SiO conversion reaction can be further promoted.
  • This decompression operation is not an absolute requirement, and the decompression facility may be appropriately determined based on the investment and its effect.
  • the degree of pressure reduction of 30 kPa to 80 kPa is not particularly limited, and is optimal depending on various operating conditions such as the particle diameter of the feed material (granulated powder), the supply amount, the output of the plasma apparatus, the temperature of the heating furnace, etc.
  • the precipitated SiO X fine powder of 0.01 ⁇ m to 10 ⁇ m is cooled with a water-cooled cyclone so that the average particle diameter D 50 grows or aggregates into a fine powder of 1 ⁇ m to 20 ⁇ m and is collected.
  • the SiO X powder produced by cooling with a compressed inert gas such as N 2 and Ar has a particle size that is too fine and poor in recovery efficiency.
  • the recovery rate of the SiO X powder is obtained by growing the particle diameter in a water-cooled cyclone. There is an effect to raise.
  • the water-cooled cyclone has an outer periphery that is water-cooled, and is blown by a high-flow rate of compressed inert gas such as SiO X fine powder and N 2 , Ar that has been primarily cooled to 800 ° C. or less.
  • the resulting SiO X fine powder is cooled to 200 ° C. or lower to grow or aggregate the particle diameter. It is preferred to recover most of the SiO X fine powder in a water-cooled cyclone.
  • the average particle diameter D 50 of the recovered SiO X fine powder by a 1 [mu] m ⁇ 20 [mu] m, when used as the negative electrode active material of a lithium ion secondary battery, it is not necessary to pass the milling step or the like, significant cost reduction effective.
  • the present invention it is preferable to collect uncollected ultra fine powder by a bag filter using a water cooling cyclone.
  • SiO X fine particles of submicron (1 ⁇ m or less) or less cannot be completely recovered. Therefore, these fine particles are completely removed by a bag filter, and the exhaust gas is discharged into the atmosphere in a clean state.
  • the present invention is to cool N 2 and Ar gas, which are clean exhaust gas after dust collected by a bag filter, with a water-cooled cyclone, to a room temperature with a heat exchanger, and further with a high-pressure blower. Pressurize and circulate through an inert gas cooler.
  • average particle diameter D 50 means a particle diameter at an integrated value of 50% in a particle diameter distribution determined by a laser diffraction / scattering method.
  • a SiO X- based active material having a large lithium ion storage capacity, a small volume expansion / contraction shrinkage of the active material coating film due to charge / discharge, and excellent charge / discharge cycle characteristics can be controlled arbitrarily.
  • it can be continuously produced at a low cost with an optimum particle size without going through a pulverization step.
  • metal Si sludge generated in a silicon wafer manufacturing process for semiconductors, solar cells, etc. is regenerated to high purity (4N or more) and is therefore excellent in environmental measures. .
  • this waste sludge can be regenerated for high purity at low cost, there is an advantage that raw material costs can be kept low.
  • this waste sludge has already had an optimal particle size distribution suitable for the purpose of granulation as a granulated powder that is a raw material used in the plasma apparatus, and the pulverization process for pulverization can be omitted. This greatly reduces costs.
  • the molten droplets of the mixed granulated powder heated and melted (partially vaporized) by the plasma flame are vaporized in the heating furnace to cause the SiO X conversion reaction, thereby generating the SiO X gas. All are gasified, and the resulting SiO X has a uniform composition. For this reason, unreacted metal Si remains, so that it is possible to solve the conventional problem that the charge / discharge characteristics and gas barrier characteristics of the lithium ion secondary battery are deteriorated, and the recovery yield of SiO X is increased. .
  • the metal Si powder and the SiO 2 powder are granulated to obtain a mixed granulated powder having an average particle diameter D 50 of 10 ⁇ m to 50 ⁇ m.
  • the material can be supplied stably with the supply device. Therefore, as in the conventional powder supply device, the smaller the particle diameter, the more unstable the supply amount, and it is difficult to produce a stable and uniform mixing ratio, and there is a special material supply device. The problem of being necessary can be solved.
  • a high temperature SiO X gas of 2,000 K (1,727 ° C.) or higher generated in a heating furnace is provided with a cooling device at the outlet of the heating furnace, and is compressed inactive such as N 2 and Ar. gas ejected mixture from the ring-shaped nozzle, rapidly cooled to 800 ° C. or less, since the precipitating SiO X fine powder can remain composition SiO X, to deposit the amorphous SiO X microparticles.
  • N 2 for the compressed inert gas because the cooling efficiency is good and the cost is low.
  • the inside of the heating furnace is operated under a reduced pressure of 30 kPa to 80 kPa, it is possible to lower the vaporization temperature of the mixed molten droplets of the metal Si powder and the SiO 2 powder and further promote the SiO X conversion reaction. it can.
  • SiO X fine powder 200 since blowing SiO X powder and N 2, compressed inert gas such as Ar that has been primary cooling to 800 ° C. or less at a high flow rate circumferentially of water cooling cyclone, SiO X fine powder 200 Since the particle diameter grows or aggregates when cooled to below °C, most of the SiO X fine powder can be recovered in a water-cooled cyclone. Further, the average particle diameter D 50 of the recovered SiO X fine powder can be set to 1 ⁇ m to 20 ⁇ m.
  • the average particle diameter D 50 of the recovered SiO X fine powder is 1 ⁇ m to 20 ⁇ m, it is necessary to go through a fine pulverization step or the like when used as a negative electrode active material of a lithium ion secondary battery. There is no significant cost reduction effect.
  • submicron (1 ⁇ m or less) SiO X fine particles that cannot be completely recovered by a water-cooled cyclone can be completely removed by a bag filter, and the exhaust gas can be discharged into the atmosphere in a clean state.
  • clean exhaust gas after collecting and collecting SiO X particulates with a bag filter is cooled to room temperature with a heat exchanger, then boosted with a high-pressure blower, and recycled to the cooling device. Cost reduction is possible.
  • the working gas N 2 , Ar gas, etc.
  • the extent to which the inert gas is circulated and used can be determined by the equipment cost and the running cost for the exhaust gas after the bag filter is clean.
  • the cross-sectional structure of the SiO X powder production apparatus used in the first embodiment of the SiO X powder production method according to the present invention is a diagram schematically showing. It is a schematic diagram which shows the cross-sectional structure of the DC plasma gun front-end
  • the cross-sectional structure of the SiO X powder production apparatus used in the second embodiment of the SiO X powder production method according to the present invention is a diagram schematically showing. It is a diagram showing a sectional structure of a cooling device for cooling by compressed N 2 gas in FIG.
  • the SiO X powder manufacturing method of the present embodiment will be described based on the steps (A) to (E).
  • the DC (direct current) plasma apparatus 1 is operated to supply the mixed granulated powder 5 of the metal Si powder and the SiO 2 powder from the powder supply nozzle 4 to the plasma flame 3 ejected from the plasma gun 2.
  • the mixed granulated powder 5 is heated and melted (partially vaporized).
  • the mixed granulated powder 5 is granulated by mixing the metal Si powder and the SiO 2 powder in the powder granulator 13, and then the powder supply disposed near the plasma gun tip 2 a via the powder feeder 14. It is supplied from the nozzle 4 to the plasma flame 3.
  • the molten droplets of the mixed granulated powder 5 that has been heated and melted (partially vaporized) in the step (A) are placed in the graphite tube (reaction tube) 15 of the high-frequency induction heating furnace 19. It is vaporized at a high temperature to cause the SiO X conversion reaction.
  • the SiO X gas generated in the step (B) is rapidly cooled using a compressed inert gas such as N 2 or Ar in the gas cooling device 20 to precipitate the SiO X fine powder 25a.
  • the SiO X fine powder 25a deposited in the step (C) is cooled by the water-cooled cyclone 24 and recovered as a fine powdery SiO X powder 25b grown or aggregated.
  • uncollected ultrafine powder is collected by the bag filter 27 by the water cooling cyclone 24 and collected.
  • a SiO X fine powder used as a vapor deposition material of the negative electrode active material and the gas barrier film of the lithium ion secondary battery it is possible to obtain a SiO X fine powder used as a vapor deposition material of the negative electrode active material and the gas barrier film of the lithium ion secondary battery.
  • the SiO X powder manufacturing apparatus of the present embodiment includes a DC (direct current) plasma apparatus 1 including a plasma gun 2 that ejects a plasma flame 3.
  • a powder supply nozzle 4 for spraying a mixed granulated powder 5 of a metal Si powder and a SiO 2 powder in a plasma flame 3 ejected from a DC (direct current) plasma apparatus 1 is arranged in the vicinity of the plasma gun tip 2a. .
  • the molten droplets of the mixed granulated powder 5 that is heated and melted (partially vaporized) by the plasma flame 3 ejected from the DC (direct current) plasma apparatus 1 are vaporized.
  • a high frequency induction heating furnace 19 for performing the SiO x conversion reaction is disposed.
  • a cooling device 20 is disposed that rapidly cools the SiO x gas generated in the high-frequency induction heating furnace 19 with an inert gas to precipitate the SiO x fine powder 25a.
  • a water-cooled cyclone 24 that cools the SiO X fine powder 25 a deposited by the cooling device 20 and collects it as a fine powdery SiO X powder 25 b grown or aggregated is disposed.
  • a bag filter 27 for collecting and collecting uncollected SiO x fine powder by the water-cooled cyclone 24 is disposed.
  • the metal Si sludge generated in the semiconductor or solar cell silicon wafer manufacturing process is regenerated into the metal Si powder used in the mixed granulated powder 5 of the metal Si powder and the SiO 2 powder in the step (A). And use it.
  • the powder particle diameter, impurity content, moisture content, and the like vary depending on the location where the metal Si sludge is generated, it is pretreated according to its properties and refined into metal Si powder.
  • purification methods such as impurity removal, dehydration, pulverization of agglomerated powder, and drying, and the method is not particularly limited.
  • the metal Si powder and the SiO 2 powder those having an average particle diameter D 50 of 10 ⁇ m or less, more preferably, an average particle diameter D 50 of 5 ⁇ m or less are used.
  • each average particle diameter D 50 exceeds 10 ⁇ m, the variation in the mixing ratio of the metal Si powder and the SiO 2 powder in one particle when granulated increases. Further, the surface area of the contact interface between the metal Si powder and the SiO 2 particles when blown into the plasma flame 3 to form a molten droplet is reduced, and the effect of increasing the reactivity between the metal Si and SiO 2 is less likely to occur.
  • the lower limit of the average particle diameter D 50 of the SiO 2 powder is not particularly limited.
  • the metal Si powder may natural oxide film on the outermost surface
  • the average particle diameter D 50 is fine particles of less than 1 [mu] m, high reactivity, it is difficult to handle. Therefore, the lower limit of the average particle diameter D 50 of the metal Si powder and 1 [mu] m.
  • the mixing ratio of the metal Si powder and the SiO 2 powder is adjusted so that the X value of the target SiO X powder is 0.5 to 1.8.
  • the lithium ion storage capacity and charge / discharge cycle characteristics due to volume expansion / contraction due to charge / discharge of the SiO X coating film are inversely proportional to the magnitude of the X value. It is necessary to select an optimum value among X values of 0.5 to 1.8. When the X value is less than 0.5, the lithium ion storage capacity increases, but the charge / discharge cycle characteristics due to the expansion and contraction of the active material film deteriorate, which is not practical. When the X value exceeds 1.8, the expansion and contraction of the active material film has almost no problem, but an increase in the lithium ion storage capacity cannot be expected so much.
  • silica and alumina are compared as a gas barrier material, silica has better gas barrier properties and flexibility, but has the disadvantage of being yellowish, and alumina is colorless and transparent and cheap, but hard and brittle. There is a disadvantage that the gas barrier property is inferior.
  • the silica deposited film is used in an oxidized state where the X value of SiO X is about 1.5 to 1.8. When the X value approaches 1.0, the gas barrier property is increased, but it becomes yellowish. On the contrary, when the X value approaches 2.0, there is a problem that the color tone becomes thin but the gas barrier property is lowered, and the control of the degree of oxidation becomes important.
  • the X value can be selected depending on the use of the film depending on whether the gas barrier property is taken or the transparency of the film is taken.
  • the important thing is that it does not contain metallic Si, the X value in the case of gas barrier material is 1.5 to 1.8, and the X value in the case of the negative electrode active material of lithium ion secondary battery is about 0.5 to 1.8. It is to build stably to the target value.
  • the average particle diameter D 50 of the mixed granulated powder 5 of metal Si powder and SiO 2 powder is preferably 10 ⁇ m to 50 ⁇ m, and the average particle diameter D 50 is more preferably 15 ⁇ m to 40 ⁇ m. This is because when the average particle diameter D 50 is less than 10 ⁇ m, the supply amount of the powder supply device 14 to the plasma gun 2 varies greatly, and stable production of SiO X cannot be performed.
  • the granulation method of the metal Si powder and the SiO 2 powder is not particularly limited, such as a spray drying method, a tumbling granulation method, a fluidized granulation method, a stirring granulation method, etc.
  • a spray drying method is preferred.
  • fine particles (primary particles) of up to several ⁇ m and a liquid organic binder are mixed in a mixing tank, slurried, then fed into a chamber by a pump and sprayed with compressed air. This is dried as agglomerated particles (secondary particles) from above by a dry air stream and collected by the lower collector.
  • the organic binder polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), starch, paraffin, resin or the like is used.
  • step (A) a DC (direct current) plasma apparatus 1 was used as the plasma heating apparatus.
  • the plasma gun tip 2 a is an electrode in which the cathode 7 is disposed in the working gas passage 8 and the working gas (N 2 or the like) 9 is ejected from the working gas passage 8 along the cathode 7.
  • a holder 6 and a nozzle 10 composed of an anode communicating with the electrode holder 6 are provided.
  • a water jacket 11 that is cooled by cooling water 12 is provided on the outer periphery of the nozzle 10.
  • a working gas (N 2 or the like) 9 ejected from the electrode holder 6 is ejected from the plasma gun tip 2a as a plasma flame 3 by discharge between the cathode 7 and the anode. Further, the plasma gun tip 2a increases the diameter of the nozzle 10 in order to slow down the ejection speed of the plasma flame 3, so that the speed of the plasma flame 3 is 150 m / sec or less, and the reaction time is increased to increase the metal Si powder.
  • This is a special structure that promotes the melting and vaporization of the mixed granulated powder 5 of SiO 2 and SiO 2 powder.
  • a mixed granulated powder 5 of metal Si powder and SiO 2 powder is supplied by a carrier gas (N 2 or the like) toward a plasma flame 3 ejected from the plasma gun 2
  • a powder supply nozzle 4 of a supply system is arranged.
  • the powder supply nozzle 4 has an internal supply system and an external supply system (not shown). From the viewpoint of efficiently supplying the material to the high temperature part of the plasma flame 3 and increasing the melting efficiency of the material, the internal supply method is preferable. However, in the internal supply method, the anode constituting the nozzle 10 is easily damaged.
  • the powder supply location is preferably from 1 to 4 locations in the circumferential direction of the nozzle 10 toward the center of the plasma flame 3.
  • a powder supply device 14 for supplying a mixed granulated powder 5 of a metal Si powder and a SiO 2 powder granulated by the powder granulator 13 is connected to the powder supply nozzle 4 via a pipe.
  • the DC (direct current) plasma device 1 is used as the plasma device for realizing the step (A).
  • the present invention is not limited to the DC (direct current) plasma device 1, but RF (high frequency induction).
  • a thermal plasma apparatus or the like may be used.
  • the DC (direct current) plasma apparatus 1 is preferable in order to have high thermal energy conversion efficiency, to completely vaporize the metal Si powder, and to efficiently process the SiO X conversion reaction in a large amount.
  • the DC (direct current) plasma apparatus 1 can melt the mixed granulated powder 5 of metal Si powder and SiO 2 powder at a high temperature of 6,000 K (5,727 ° C.) or more with the plasma flame 3.
  • SiO X can be combined with the step (B) of completely vaporizing the high temperature induction furnace 19 at a high temperature of 2,000 K (1,727 ° C.) or higher.
  • a normal DC (direct current) plasma apparatus is characterized in that the velocity of the flame, which is the plasma flame 3 of the plasma jet, is obtained at a high flow rate of Mach 2 level.
  • the speed of the frame at the outlet of the plasm gun tip 2a is made as low as possible. Therefore, the diameter of the nozzle 10 of the plasma gun tip 2a is increased so as to slow down the flying speed of the raw material powder, and the flying speed of the SiO X droplet is set to 150 m / sec to 3 m / sec. 19 is blown into the structure.
  • the diameter of the nozzle 10 of the plasma gun tip 2a is configured to expand stepwise or in a curve toward the tip of the nozzle 10 in order to adjust the flying speed of the SiO X droplet, and the anode and cathode 7 is a structure that can be exchanged as a pair of parts combined with a structure that maintains the distance to 7 appropriately.
  • the flying speed of the SiO X droplet exceeds 150 m / sec, the reaction time in the high-frequency induction heating furnace 19 is short, and it is difficult to cause the reaction to be completely vaporized in the high-frequency induction heating furnace 19.
  • the flying speed of the SiO X droplet is less than 3 m / sec, a coarse droplet that cannot be vaporized does not fly to the optimum reaction temperature portion in the high-frequency induction heating furnace 19 and may accumulate on the bottom of the high-frequency induction heating furnace 19. is there.
  • an RF (high frequency induction) thermal plasma apparatus can produce a high-temperature plasma flame of 10,000 K (9,727 ° C.) or higher, but has a low thermal energy conversion efficiency to plasma, and a feed rate of 10 g / min. Therefore, the productivity is poor and the production cost is high, which is not preferable as a mass production apparatus.
  • a high frequency induction heating furnace 19 is connected to the tip of the DC (direct current) plasma apparatus 1 in order to realize the step (B).
  • a graphite tube (reaction tube) 15 having a heat-resistant temperature of 3,000 ° C., which is covered with a heat insulating material 16, is inserted into the water-cooled quartz tube 17, and the high-frequency induction furnace is disposed around the water-cooled quartz tube 17.
  • the coil 18 is arranged.
  • the internal temperature of the graphite tube (reaction tube) 15 can be arbitrarily controlled from 1,600 ° C. to 2,700 ° C.
  • the opening 15a provided in the upper part of the graphite tube (reaction tube) 15 is cooled by cooling with a compressed inert gas such as N 2 or Ar in order to realize the step (C).
  • a device 20 is arranged.
  • the high-frequency induction heating furnace 19 for realizing the step (B) has a temperature in the graphite tube (reaction tube) 15 of 2,000 K (1,727 ° C.) or higher so that the SiO X conversion reaction is sufficiently performed. It is preferable to use a graphite tube having a high heat resistance temperature.
  • a method of producing SiO X by blowing metal Si powder into a DC (direct current) plasma jet and using oxygen gas O 2 as a working gas is also conceivable.
  • a cooling device 20 that performs cooling with a compressed inert gas such as N 2 or Ar is connected to an opening 15 a provided at an upper portion of a graphite tube (reaction tube) 15, and has a normal temperature.
  • the ring-shaped nozzle 22 is connected to a pipe line 22a that communicates with a device (not shown) that supplies a compressed inert gas such as N 2 or Ar at room temperature.
  • the heat insulation double pipe 23 is provided with an inlet 23a for taking in cooling water or a compressed inert gas such as N 2 and Ar, and an outlet 23b.
  • the high temperature SiO X gas of 2,000 K (1,727 ° C.) or more generated in the graphite tube (reaction tube) 15 of the high frequency induction heating furnace 19 is the upper part of the graphite tube (reaction tube) 15 of the high frequency induction heating furnace 19. It is introduced into the cooling device 20 that is connected to the opening 15a.
  • a compressed inert gas such as N 2 or Ar is jetted in an oblique direction from a ring-like nozzle 22 that jets in a ring shape, and high-temperature SiO X gas is sucked by the ejector effect and instantly cooled to 800 ° C. or less, Amorphous SiO X fine powder 25a is deposited. This SiO X gas becomes an almost stable solid at 800 ° C. or lower.
  • the SiO X precipitate is deposited as submicron (1 ⁇ m or less) amorphous SiO X fine powder 25a without being disproportionated into the metal Si powder and the SiO 2 powder. Since the particle diameter of the SiO X fine powder 25a is very fine with a submicron (1 ⁇ m or less), it is difficult to collect with a normal cyclone. Therefore, by blowing compressed inert gas such as N 2 or Ar for primary cooling, the gas flow rate in the heat insulating double pipe 23 is increased, and the water is cooled primarily to 800 ° C. or less in the circumferential direction in the water cooling cyclone 24. Introduced high temperature gas.
  • compressed inert gas such as N 2 or Ar
  • the heat insulating double pipe 23 serving as a guide pipe to the water cooling cyclone 24
  • the heat insulating double pipe 23 is N 2 , Ar for cooling water or primary cooling.
  • cooling is performed through a compressed inert gas such as the like, and the inert gas is blown from the ring-shaped nozzle 22.
  • the heat insulation double tube 23 is cooled with water or a cooling gas. However, if it is cooled too much, SiO X gas is deposited as a SiO X solid and deposited in the heat insulation double tube 23, and the heat insulation double tube 23 is clogged. End up. In order to collect the SiO X solid (powder or flakes) deposited and deposited in the heat insulating double tube 23, the operation must be a batch operation in a short cycle. Therefore, when the heat insulation double pipe 23 is indirectly cooled with water, it is necessary to adjust the flow rate and the like so as to maintain a temperature at which the SiO X gas does not precipitate in the heat insulation double pipe 23.
  • the insulated double pipe 23 temperature can be maintained at a high temperature. Moreover, since the gas flow rate in the pipe is very fast, problems such as deposit clogging do not occur.
  • process (D) is demonstrated.
  • the heat insulating double tube 23 of the cooling device 20 that performs cooling with a compressed inert gas such as N 2 or Ar communicates with the water cooling cyclone 24.
  • the SiO X fine powder 25a cooled here grows or aggregates as the particle size grows and agglomerates and deposits on the side walls and the lower part of the cyclone.
  • a hopper 26 that recovers the SiO X powder 25b that has been cooled by the water-cooled cyclone 24 and whose particle diameter has grown or aggregated and deposited and deposited on the side wall and the lower part of the cyclone.
  • the cooling efficiency is very good, and the fine powder SiO X powder 25b is further rapidly cooled, so that the particle size becomes a secondary particle. greatly grow or aggregate as an average particle diameter D 50 is the powder of 10 [mu] m ⁇ 20 [mu] m.
  • D 50 is the powder of 10 [mu] m ⁇ 20 [mu] m.
  • the SiO X gas when the SiO X gas is rapidly cooled with a compressed inert gas such as N 2 or Ar, the size of the precipitation growth nuclei varies depending on the cooling rate, but generally becomes a fine powder of 0.01 ⁇ m to several ⁇ m, and the amorphous non-crystalline It can be a crystal structure.
  • SiO usually has a metastable crystal structure and has an amorphous aggregate structure of metal Si and SiO 2 , but when heated in a high temperature region of 800 ° C. or higher, it gradually becomes dissociated by the disproportionation reaction. Separated into SiO 2 region.
  • the particle diameter is preferably adjusted to 0.01 ⁇ m to 10 ⁇ m by adjusting the amount of compressed inert gas such as N 2 or Ar.
  • Nanoparticles with a particle size of SiO X fine powder of less than 0.01 ⁇ m have a large particle surface area and are difficult to knead with a binder when used as a negative electrode active material for a lithium ion secondary battery. Problems are likely to occur.
  • particles having a particle size of SiO X fine powder exceeding 10 ⁇ m are liable to crack or peel off from the electrode due to volume expansion / contraction due to absorption / release of lithium ions, and as a negative electrode active material for lithium ion secondary batteries. Is not preferred.
  • process (E) is demonstrated.
  • the water-cooled cyclone 24 communicates with a bag filter 27 that sucks and collects the SiO X fine powder not deposited here by a vacuum pump 28 via a pipe line 24a.
  • the submicron (1 ⁇ m or less) SiO X fine powder that could not be collected in the water-cooled cyclone 24 is removed by the bag filter 27 in step (E), and clean exhaust gas is released to the atmosphere.
  • the dust collected here is also collected as a SiO X powder product, the product yield is also increased.
  • the inside of the high-frequency induction heating furnace 19 is operated under a reduced pressure of 30 kPa to 80 kPa, thereby lowering the reaction temperature between the metal Si powder and the SiO 2 powder and further promoting the SiO X conversion reaction. Can do.
  • all the processes from the high-frequency induction heating furnace 19 to the bag filter 27 are operated under reduced pressure by suctioning with the vacuum pump 28 behind the bag filter 27.
  • the vaporization temperature of SiO X is lowered, so that the temperature in the high-frequency induction heating furnace 19 can be kept low, and the heating capacity of the high-frequency induction coil 18 can also be reduced.
  • the cooling device 20 introduces an initially charged compressed inert gas into a pipeline 22 a connected to the ring-shaped nozzle 22 via a three-way valve 22 b and a circulating compressed inert gas.
  • the pipe line 22d to be connected is connected.
  • the inert gas circulation device includes a bag filter 27 and an inert gas cooling device 34.
  • the bag filter 27 is provided with a conduit 29 that guides clean exhaust gas that has passed through the bag filter 27.
  • the bag filter 27 communicates with the water cooling cyclone 24 via a pipe line 24a.
  • the inert gas cooling device 34 is provided on the downstream side of the pipe line 29, the heat exchanger 30 for cooling the exhaust gas to room temperature, the pipe line 31 provided on the downstream side of the heat exchanger 30, and the pipe line
  • the high pressure blower 32 is provided downstream of the high pressure blower 31 and boosts the exhaust gas.
  • the high pressure blower 32 is connected to the downstream side of the high pressure blower 32 and the pipe 22 d of the cooling device 20.
  • the pipe 33 is provided with an exhaust pipe 35 through a three-way valve 36 that discharges surplus gas equivalent to the working gas (N 2 , Ar gas, etc.) blown by the plasma gun 2 to the atmosphere.
  • Example 1 As a primary raw material of metal Si powder, metal Si powder regenerated from metal Si sludge generated in a silicon wafer production process for semiconductor production was used. The purity of the metal Si powder was impurity heavy metal ⁇ 50 ⁇ g / g, average particle diameter D 50 : 3.7 ⁇ m. The particle size distribution of the SiO 2 powder was an average particle size D 50 : 2.4 ⁇ m. A powder obtained by mixing metal Si powder and SiO 2 at a weight ratio (wt%) of 1: 2.14 (X value of SiO X : 1.0), water, an organic binder (PVA), and a dispersant.
  • wt% weight ratio
  • the average particle diameter D 50 of the mixed granulated powder 5 was 17 ⁇ m ( ⁇ 60 ⁇ m).
  • a DC (direct current) plasma apparatus manufactured by Nippon Yutech Co., Ltd .: SG-100 spray gun 1 was used as the plasma heating apparatus.
  • a special nozzle in which the diameter of the nozzle 10 at the plasma gun tip 2a is increased in order to slow down the ejection speed of the plasma flame 3.
  • a mixed granulated powder 5 of metal Si powder and SiO 2 powder was supplied to a DC (direct current) plasma apparatus 1 by a carrier gas (N 2 ) at a supply rate of 30 g / min.
  • N 2 60 L / min
  • a high frequency induction heating furnace 19 was connected to the tip of the DC (direct current) plasma apparatus 1.
  • the high frequency induction heating furnace 19 has a structure in which a heat insulating material 16 and a graphite tube (reaction tube) 15 having a heat resistant temperature of 3,000 ° C. are inserted into a water-cooled quartz tube 17 and heated by a high frequency induction coil 18.
  • the internal temperature of the graphite tube (reaction tube) 15 was such that the temperature could be arbitrarily controlled from 1,600 ° C. to 2,700 ° C., and the operation was performed at 2,500 ° C.
  • the SiO X that has become molten droplets (partially gasified) by the plasma flame 3 is entirely turned into SiO X gas by being blown into the high-frequency induction heating furnace 19, and is inert from the upper part of the induction induction furnace 19. It is sent to the outlet pipe 21 of the gas cooling device 20.
  • a compressed N 2 gas at room temperature was blown into the SiO X gas at 400 L / min from the ring-shaped nozzle 22 at the outlet of the outlet pipe 21 and rapidly cooled to 800 ° C.
  • the SiO X primarily cooled to 800 ° C. becomes a fine powder from the gas, and is further blown into the water-cooled cyclone 24.
  • the SiO X fine powder cooled by the water cooling cyclone 24 grows in particle size, adheres and accumulates on the side wall and the lower portion of the water cooling cyclone 24, and is collected in a hopper 26 provided at the lower portion of the water cooling cyclone 24.
  • the SiO X recovered powder collected at the bottom of the water-cooled cyclone 24 was sampled and subjected to particle size analysis and component analysis.
  • the SiO X recovered powder collected at the bottom of the water-cooled cyclone 24 was sampled and subjected to particle size analysis and component analysis.
  • the SiO X recovered powder collected at the bottom of the water-cooled cyclone 24 was sampled and subjected to particle size analysis and component analysis.
  • the analysis result of the SiO X recovered powder sample is X in both EDS analysis and XPS analysis.
  • the value was almost the same as the calculated X value at the raw material powder mixing ratio. It was also confirmed that the raw material Si component and SiO 2 component were almost lost even in the SiO X bonded state of the SiO X recovered powder sample, and Sub-oxide (Si 1+ , Si 2+ , Si 3+ ) was generated. .
  • the particle size distribution of the SiO X recovered powder sample is also suitable for application of the negative electrode active material of a lithium ion secondary battery having an average particle size D 50 : 18 ⁇ m to 33 ⁇ m (> 50 ⁇ m: 0% to 26%). It could be recovered as a fine powder of distribution.
  • the X value of SiO X can be optimally controlled according to the use, and the recovered SiO X is a powder having a particle size distribution suitable for application of the negative electrode active material of the lithium ion secondary battery.
  • the pulverization step for adjusting the particle size can be omitted, and the SiO X powder production cost can be greatly reduced.
  • Example 1 The raw material of the metal Si powder is put in a powder at a supply rate of 70 g / min into a plasma jet of a DC (direct current) plasma apparatus (manufactured by Nippon Yutech Co., Ltd .: SG-100 spray gun), and further SiO in the plasma flame 3
  • the fine powder having an average particle diameter D 50 of about 5 ⁇ m cannot be stably supplied by the powder supply device 14 of the plasma gun 2 because the powder is too fine.
  • the material supply was very unstable, and the recovered powder was composed of metal Si and SiO 2 despite being heated in the high-frequency induction heating furnace 19 after the plasma jet. There were many compositions, and SiO conversion reaction did not occur so much.
  • the metal Si powder is not granulated because it is not granulated, it is difficult for the powder to enter the center of the plasma flame 3, and the metal Si cannot be completely vaporized due to its high vaporization temperature. The gas phase reaction was difficult to occur.
  • Example 3 The operation was performed under the same conditions as in Example 1 except that heating in the high-frequency induction heating furnace 19 was not performed. Since the material is granulated, the material is melted in the plasma flame 3 because the raw material particle diameter is large. However, since the temperature of the plasma flame 3 rapidly decreases, the molten droplets of the mixed granulated powder 5 are solidified without being vaporized as they are. Moreover, since the particle diameter of the recovered powder is very large and no gas phase reaction is performed, a mixture of metal Si and SiO 2 in the form of particulate powder is large.
  • Comparative Example 4 A normal DC (direct current) plasma device (manufactured by Nippon Yutec Corp .: SG-100 spray gun) is used instead of a special nozzle in which the diameter of the nozzle 10 at the tip 2a of the plasma gun is increased in order to slow down the ejection speed of the plasma flame 3.
  • a normal DC (direct current) plasma apparatus that does not employ a special nozzle, the flying speed of molten droplets is very fast, and the residence time in the high-frequency induction heating furnace 19 is very short. Compared with Comparative Example 3, vaporization of the molten droplets was considerably carried out, but it was not sufficient.
  • Example 5 The same conditions as in Example 1 except that the high-temperature gas (about 1,700 ° C.) discharged from the high-frequency induction heating furnace 19 is discharged as it is into the heat insulating double tube 23 without performing the primary quenching with the compressed N 2 gas. Operated at. The high-temperature SiO X gas is released into the atmosphere of the water-cooled cyclone 24 through the heat insulating double tube 23, but the gas flow rate is slow and most of the gas is precipitated and solidified in the heat insulating double tube 23 or enters the cyclone. The particles also did not settle in the water cooled cyclone 24 and the yield was very bad.
  • the high-temperature gas about 1,700 ° C.

Abstract

The purpose of the present invention is to manufacture, continuously and at a low cost, an SiOx powder which is to be used as a negative electrode active material for a lithium ion secondary battery or a vapor deposition material for a gas barrier film. This SiOx powder manufacturing process comprises: a step for subjecting a granulated powder of a mixture of metallic Si powder and SiO2 powder to heat-melting with a plasma flame; a step for subjecting the droplets of the heat-melted granulated powder to vaporization and conversion into SiOx in a heating furnace; and a step for cooling the formed SiOx gas with an inert gas rapidly to precipitate an SiOx fine powder.

Description

ＳｉＯＸ粉末製造法及びＳｉＯＸ粉末製造装置SiOX powder manufacturing method and SiOX powder manufacturing apparatus
　本発明は、リチウムイオン二次電池の負極活物質及びガスバリアフィルムの蒸着材料として用いられるＳｉＯＸ粉末の製造法及び製造装置に関する。 The present invention relates to a method and an apparatus for producing SiO X powder used as a negative electrode active material for a lithium ion secondary battery and a vapor deposition material for a gas barrier film.
　近年、携帯型の電子機器、通信機器等の著しい発展に伴い、経済性又は機器の小型化、軽量化の観点から、更には電気自動車、風力発電、太陽電池の蓄電用の観点から、高エネルギー密度、高容量の二次電池の開発が強く要望されている。リチウムイオン二次電池は、高寿命、高容量であることから、電源市場において高い需要の伸びを示している。
　リチウムイオン二次電池は、正極、負極及びこれら両極の間に電解液を含浸させたセパレータを有し、充放電によってリチウムイオンが電解液を介し正極と負極との間を往復するように構成されている。
　負極には、リチウムイオンの吸蔵放出が可能な活物質（負極活物質）が用いられ、現状では、カーボン系負極材が一般的である。 In recent years, with the remarkable development of portable electronic devices, communication devices, etc., high energy from the viewpoint of economy or miniaturization and weight reduction of devices, and also from the viewpoint of storage of electric vehicles, wind power generation, solar cells. There is a strong demand for the development of secondary batteries with high density and high capacity. Since lithium ion secondary batteries have a long life and a high capacity, they show a high demand growth in the power supply market.
A lithium ion secondary battery has a positive electrode, a negative electrode, and a separator impregnated with an electrolytic solution between the two electrodes, and is configured such that lithium ions reciprocate between the positive electrode and the negative electrode through the electrolytic solution by charging and discharging. ing.
For the negative electrode, an active material capable of occluding and releasing lithium ions (negative electrode active material) is used, and at present, a carbon-based negative electrode material is common.
　ところが、カーボン系負極活物質のエネルギー密度向上は限界にきており、エネルギー密度の更なる向上を目指して様々な負極活物質の開発が進められている。その中でもＳｉ系負極活物質が非常に有望な材料として注目を浴びている。
　金属Ｓｉを負極活物質に用いると、リチウムイオン吸蔵容量はカーボン系負極活物質の１０倍位の吸蔵容量がある。しかし、吸蔵容量が大きいため充放電時の金属Ｓｉの体積膨張収縮が大きく、金属コーティング皮膜の亀裂により充放電のサイクル特性が急激に低下し、実用できる状況に至っていない。
　金属Ｓｉよりリチウムイオン吸蔵容量は落ちるが、充放電時の体積膨張収縮が小さく、充放電のサイクル特性が低下しにくい材料として、ＳｉＯを使用すると効果的であることが知られている。 However, the improvement in the energy density of the carbon-based negative electrode active material has reached its limit, and various negative electrode active materials have been developed with the aim of further improving the energy density. Among them, Si-based negative electrode active materials are attracting attention as very promising materials.
When metal Si is used for the negative electrode active material, the lithium ion storage capacity is about 10 times that of the carbon-based negative electrode active material. However, since the storage capacity is large, the volumetric expansion and contraction of metal Si during charge / discharge is large, and the cycle characteristics of charge / discharge are rapidly deteriorated due to cracks in the metal coating film.
Lithium ion storage capacity is lower than that of metal Si, but it is known that it is effective to use SiO as a material in which volume expansion / contraction during charge / discharge is small and charge / discharge cycle characteristics are unlikely to deteriorate.
　しかし、ＳｉＯは、ＳｉＯＸのＸ値の変化により、リチウムイオン吸蔵容量、充放電に伴う体積膨張収縮の程度がそれぞれ異なる。従って、どこに最適点を求めるかは、カーボン系負極活物質との配合比率、バインダーの選択等対応手段が様々である。それに併せてＳｉＯＸのＸ値を任意にコントロールできる製造手段が求められている。
　一般的に、ＳｉＯＸの製造法の多くは、加熱炉でＳｉＯＸガスを発生させ、それを析出基体に析出させて塊状のＳｉＯＸ製品を造る。これを粉砕し粒子径の調整をしてリチウムイオン二次電池用の負極活物質粉末を製造している。
　この方式で微粉末を造るには、加熱炉への材料投入や析出ＳｉＯＸの回収がバッチ式であるため、生産性が低い。また、粉砕し粒子径を調整する工程での製造コストが非常に大きいことや粉砕時に不純物が混入し易いという問題がある。 However, SiO has different lithium ion storage capacity and volume expansion / contraction due to charge / discharge depending on the change of X value of SiO X. Accordingly, there are various means for determining the optimum point, such as the blending ratio with the carbon-based negative electrode active material and the selection of the binder. In conjunction with this, a manufacturing means capable of arbitrarily controlling the X value of SiO X is required.
In general, many of the preparation of SiO X, to generate a SiO X gas in a heating furnace, it is precipitated in the precipitation substrate produce SiO X product bulk. This is pulverized and the particle diameter is adjusted to produce a negative electrode active material powder for a lithium ion secondary battery.
In order to produce a fine powder by this method, since the material input to the heating furnace and the recovery of the deposited SiO 2 X are batch methods, the productivity is low. In addition, there are problems that the manufacturing cost in the step of pulverizing and adjusting the particle diameter is very high, and impurities are easily mixed during pulverization.
　これに対し、ＳｉＯＸの製造法に関する様々な技術が提案されている。
　例えば、特許文献１には、一酸化珪素の製造方法が開示されている。特許文献１の製造方法は、まず、シリコン金属粉末を、キャリアガスを用いて７０ｇ／ｍｉｎ以上の供給量で、雰囲気ガス中に噴出しているプラズマジェット中に投入する。次に、このプラズマジェット中で蒸気としたシリコン金属粉未を、キャリアガス及び雰囲気ガスのうち少なくとも何れか一方に含有されている酸素ガスと接触させて合成反応を起こさせる。次に、この合成反応で生じる反応フレームを維持しつつ連続的に一酸化珪素蒸気を生成する。次に、この生成する一酸化珪素蒸気を急冷して得られた粗生成物を１，４００℃～１，８００℃で蒸留して一酸化珪素を得ている。
　また、特許文献２には、リチウムイオン二次電池の負極活物質及びガスバリアフィルムの蒸着材料として用いられるＳｉＯＸ（Ｘ＜１）の製造方法が開示されている。特許文献２の製造方法は、まず、金属Ｓｉ粉末とＳｉＯ２粉末又はＳｉＯ粉末からなる混合原料をプラズマ加熱により気化させてＳｉＯガスとする。次に、析出基板に珪素酸化物ＳｉＯＸ（Ｘ＜１）として析出させた後、これをボールミルで破砕して粉末状の珪素酸化物を得ている。 On the other hand, various techniques relating to a method for producing SiO X have been proposed.
For example, Patent Document 1 discloses a method for producing silicon monoxide. In the manufacturing method disclosed in Patent Document 1, first, silicon metal powder is introduced into a plasma jet ejected into an atmospheric gas at a supply rate of 70 g / min or more using a carrier gas. Next, the silicon metal powder not vaporized in the plasma jet is brought into contact with oxygen gas contained in at least one of the carrier gas and the atmospheric gas to cause a synthesis reaction. Next, silicon monoxide vapor is continuously generated while maintaining the reaction frame generated in the synthesis reaction. Next, the crude product obtained by quenching the generated silicon monoxide vapor is distilled at 1,400 ° C. to 1,800 ° C. to obtain silicon monoxide.
Patent Document 2 discloses a method for producing SiO x (X <1) used as a negative electrode active material for a lithium ion secondary battery and a vapor deposition material for a gas barrier film. In the manufacturing method of Patent Document 2, first, a mixed raw material composed of metal Si powder and SiO 2 powder or SiO powder is vaporized by plasma heating to form SiO gas. Next, after depositing as silicon oxide SiO X (X <1) on the deposition substrate, it was crushed by a ball mill to obtain powdered silicon oxide.
　食品包装や医療品及び医薬品を処理する分野では、食品や医薬品等の劣化防止のため、酸素や水分が包装材料を透過しないように、包装材料には高いガスバリア性が求められている。
　近年、ガスバリア性が高く、透明性に優れるＳｉＯ蒸着膜を有する包装材料が注目されている。例えば、高分子フィルムにＳｉＯ蒸着膜を成膜させた食品包装フィルム等が生産されている。なお、透明性に優れることは、外観から包装内容物を観察して変質や劣化を確認するために必要である。特に、食品等を包装する包装用材料にとっては必須の特性といえる。 In the field of processing food packaging, medical products, and pharmaceuticals, the packaging material is required to have high gas barrier properties so that oxygen and moisture do not permeate the packaging material in order to prevent deterioration of the food, pharmaceuticals, and the like.
In recent years, a packaging material having a SiO vapor deposition film having high gas barrier properties and excellent transparency has been attracting attention. For example, food packaging films in which a SiO film is formed on a polymer film are produced. It should be noted that excellent transparency is necessary for observing the package contents from the appearance and confirming alteration and deterioration. In particular, it can be said to be an essential property for packaging materials for packaging foods and the like.
特開昭６０－２１５５１４号公報JP-A-60-215514 特開２０１１－７９７２４号公報JP 2011-79724 A
　特許文献１には、金属シリコン供給量７０ｇ／ｍｉｎ以上、金属粉末粒子径４００μｍ以下（平均粒子径１００μｍ）が好ましいことが記載されている。また、プラズマジェット中に供給されたシリコン金属粉末は蒸気となり、酸素ガスと反応させて一酸化珪素を合成することが記載されている。更に、反応フレーム内の温度はプラズマからの熱及び反応熱により３，０００Ｋ（２，７２７℃）以上に昇温することが記載されている。
　しかし、一般的にはＤＣ（直流）プラズマジェットのプラズマ炎の速度は３００ｍ／ｓｅｃ以上と非常に高速である。従って、金属Ｓｉ粉末の粒子径が５０μｍを超えるような大きな粒子は溶融して液滴にはなっても、短時間では蒸発（気化）せず、金属Ｓｉが大量に残るという問題がある。
　一方、仮に金属Ｓｉの平均粒子径を１０μｍ以下の小さな材料にすると、材料供給が非常に不安定になる。従って、材料供給と酸素ガス供給との混合比率が時々刻々と変化して、安定したＳｉＯＸの組成のものを製造しにくいという問題がある。 Patent Document 1 describes that a metal silicon supply rate of 70 g / min or more and a metal powder particle size of 400 μm or less (average particle size of 100 μm) are preferable. In addition, it is described that silicon metal powder supplied into a plasma jet becomes vapor and reacts with oxygen gas to synthesize silicon monoxide. Further, it is described that the temperature in the reaction frame is raised to 3,000 K (2,727 ° C.) or more by heat from the plasma and reaction heat.
However, in general, the speed of a plasma flame of a DC (direct current) plasma jet is as high as 300 m / sec or more. Therefore, even if a large particle having a particle diameter of metal Si powder exceeding 50 μm is melted to form droplets, there is a problem that a large amount of metal Si remains without being evaporated (vaporized) in a short time.
On the other hand, if the average particle diameter of the metal Si is a small material of 10 μm or less, the material supply becomes very unstable. Therefore, there is a problem that the mixing ratio between the material supply and the oxygen gas supply changes every moment and it is difficult to manufacture a material having a stable SiO X composition.
　また、特許文献１には、プラズマ炎からの熱及び金属Ｓｉ蒸気と酸素との反応熱で、プラズマ炎の温度は３，０００Ｋ（２，７２７℃）以上に昇温すると記載されている。しかし、金属Ｓｉの気化熱は反応熱より遙かに大きく、材料供給量が多くなるとプラズマ炎の温度は急激に低下し、気化しきれない金属Ｓｉが大量に残るという問題がある。
　また、材料供給量と理論酸素量とを計算して目的とするストイキメトリの原子量比で投入したとしても、プラズマ炎内は温度が均一でなく部分的に温度差が大きいため、投入され飛散した金属Ｓｉとの均一な酸化反応は起こらない。従って、部分的に酸化反応が進んで、気化した金属ＳｉはＳｉＯ２になる比率が非常に多くなる。 Further, Patent Document 1 describes that the temperature of the plasma flame is increased to 3,000 K (2,727 ° C.) or higher by heat from the plasma flame and reaction heat between the metal Si vapor and oxygen. However, the heat of vaporization of metal Si is much larger than the heat of reaction, and when the amount of material supply increases, the temperature of the plasma flame rapidly decreases, and there is a problem that a large amount of metal Si that cannot be vaporized remains.
Moreover, even if the material supply amount and the theoretical oxygen amount were calculated and introduced at the target stoichiometric atomic weight ratio, the temperature was not uniform in the plasma flame and the temperature difference was partially large, so it was introduced and scattered. A uniform oxidation reaction with metal Si does not occur. Therefore, the oxidation reaction proceeds partially, and the ratio of vaporized metal Si to SiO 2 becomes very large.
　一方、特許文献２では、金属Ｓｉ粉末とＳｉＯ２粉末又はＳｉＯ粉末からなる混合原料をプラズマ加熱により気化させてＳｉＯガスとした後、析出基板に珪素酸化物ＳｉＯＸ（Ｘ＜１）として析出させることが記載されている。しかし、そのプラズマ炎の中心温度は５，０００℃～１００，０００℃にするのが好ましく、より好ましくは１０，０００℃～２０，０００℃であると記載されているだけである。特許文献２には、どのようなプラズマ装置でどのようなプラズマ操業条件、原料粒子径、材料供給速度で操業させるかは記載されていない。
　例えば、ＲＦ（高周波誘導）熱プラズマ装置を使用した場合、プラズマ炎の温度は１０，０００℃以上の超高温度であっても、プラズマ炎の熱容量は非常に小さい。従って、金属Ｓｉは粒子径の小さいものは溶融し気化するものもあるが、粒子径の大きなものは、かなり多くのものが、溶融したものがそのまま球状化固化するだけでＳｉＯは生成しにくい。 On the other hand, in Patent Document 2, a mixed raw material composed of metal Si powder and SiO 2 powder or SiO powder is vaporized by plasma heating to form SiO gas, and then deposited on a deposition substrate as silicon oxide SiO X (X <1). It is described. However, the center temperature of the plasma flame is preferably 5,000 ° C. to 100,000 ° C., more preferably only 10,000 ° C. to 20,000 ° C. Patent Document 2 does not describe what plasma operation conditions, raw material particle diameters, and material supply speeds are used in which plasma apparatus.
For example, when an RF (high frequency induction) thermal plasma apparatus is used, the heat capacity of the plasma flame is very small even if the temperature of the plasma flame is an ultrahigh temperature of 10,000 ° C. or higher. Accordingly, some metal Si having a small particle size melt and vaporize, but a large number of ones having a large particle size are spheroidized and solidified as they are, and it is difficult to produce SiO.
　これは、プラズマ炎は非常に高温ガスであるが熱容量が非常に小さく、一方、金属Ｓｉの気化熱は非常に大きいため、金属Ｓｉ投入によりプラズマ炎の温度が瞬時に急低下し、殆どの粒子は気化しないためである。加えて、プラズマ炎内に投入された金属Ｓｉ粉末とＳｉＯ２粉末又はＳｉＯ粉末からなる混合原料は、八方に飛散し、また気化温度が大きく異なるため、金属Ｓｉ粉末とＳｉＯ２粉末との混合粒子の合成反応が起こりにくいためである。
　すなわち、１０，０００℃～２０，０００℃のプラズマ炎に金属Ｓｉ粉末とＳｉＯ２粉末及び／又はＳｉＯ粉末との混合粉末を投入して、これら全てを完全気化させてＳｉＯＸ化反応を起こさせるためには、極めて少量の材料投入にするか、大容量のＲＦ（高周波誘導）熱プラズマ装置にする必要がある。従って、特許文献２では金属Ｓｉ粉末とＳｉＯ２粉末及び／又はＳｉＯ粉末との混合粉末を全て完全気化させてＳｉＯＸ化反応を起こさせるには不十分である。 This is because the plasma flame is a very hot gas but has a very small heat capacity, while the heat of vaporization of metal Si is very large. Is because it does not vaporize. In addition, the mixed raw material consisting of the metal Si powder and the SiO 2 powder or the SiO powder charged into the plasma flame is scattered in all directions and the vaporization temperature is greatly different, so the mixed particles of the metal Si powder and the SiO 2 powder This is because the synthesis reaction is difficult to occur.
That is, a mixed powder of metal Si powder and SiO 2 powder and / or SiO powder is put into a plasma flame at 10,000 ° C. to 20,000 ° C., and all these are completely vaporized to cause SiO X conversion reaction. For this purpose, it is necessary to use a very small amount of material or to use a large-capacity RF (high frequency induction) thermal plasma apparatus. Therefore, in Patent Document 2, it is insufficient to completely evaporate the mixed powder of the metal Si powder and the SiO 2 powder and / or the SiO powder to cause the SiO X conversion reaction.
　更に、特許文献２ではスプラッシュを抑制するために、ＳｉＯガスを発生する原料をプラズマ炎によって高温に加熱すると、気化した金属珪素及び酸素が原子状で反応してＳｉＯガスが発生し、このＳｉＯガスを析出させて得られるＳｉＯＸ（Ｘ＜１）は、結晶質の金属珪素及び二酸化珪素を含むことなく金属珪素が均一に分布し、非結晶質となることが有効であるとしている。
　スプラッシュとは、気化したＳｉＯガスとともに、気化していない金属珪素及び二酸化珪素の微粒子が飛散する現象である。ＳｉＯ蒸着膜を成膜する際にスプラッシュが発生すると、高分子フィルム上のＳｉＯ蒸着膜に、気化していない微細な粒子が付着し、ピンホール等の欠陥が生じ、ガスバリア性を悪化させる。 Further, in Patent Document 2, in order to suppress splash, when a raw material that generates SiO gas is heated to a high temperature by a plasma flame, vaporized metallic silicon and oxygen react in an atomic state to generate SiO gas, and this SiO gas It is said that SiO X (X <1) obtained by precipitating is effectively distributed uniformly without containing crystalline metallic silicon and silicon dioxide and becomes amorphous.
Splash is a phenomenon in which fine particles of metal silicon and silicon dioxide that are not vaporized are scattered together with vaporized SiO gas. If splash is generated when forming the SiO vapor deposition film, fine particles that are not vaporized adhere to the SiO vapor deposition film on the polymer film, causing defects such as pinholes, and gas barrier properties are deteriorated.
　しかし、特許文献２の製造方法では、上述したように金属Ｓｉ粉末及びＳｉＯ２粉末はプラズマ炎の中で気化して原子状になるどころか、気化せずに液滴のままである場合が大半である。すなわち、どのような粒子径の粉末原料をどのようなプラズマ装置のプラズマ炎（温度、プラズマ炎の速度）の中で加熱するのかが重要であるが、特許文献２にはこれについては記載されていない。
　ＤＣ（直流）プラズマ溶射ガンの１０，０００℃のプラズマ炎の温度の場合、プラズマ炎の速度が速いため、ＤＣ（直流）プラズマ溶射ガンで一般的に使用されている平均粒子径Ｄ５０が３０μｍレベルの金属Ｓｉ粉末を供給しても、大半の粉末は一部が溶融するだけでほとんどガス化しない。 However, in the manufacturing method of Patent Document 2, as described above, the metal Si powder and the SiO 2 powder are not vaporized in the plasma flame and become an atomic state, but in most cases, they are not vaporized but remain as droplets. is there. That is, it is important in what kind of particle size powder raw material is heated in which plasma flame (temperature, plasma flame speed) of the plasma apparatus, but this is described in Patent Document 2. Absent.
In the case of a temperature of 10,000 ° C. plasma flame of a DC (direct current) plasma spray gun, the average particle size D 50 generally used in the DC (direct current) plasma spray gun is 30 μm because the speed of the plasma flame is high. Even if a level of metal Si powder is supplied, most of the powder is only partially melted and hardly gasified.
　また、プラズマ炎の速度の非常に遅いＲＦ（高周波誘導）熱プラズマ装置の１０，０００℃のプラズマ炎の中に、更に粒子径の小さい平均粒子径Ｄ５０が２０μｍレベルの金属Ｓｉ粉末を３０ｇ／ｍｉｎの少ない供給量で操業しても、気化せず金属Ｓｉがそのまま溶融球状化した粒子となって回収されるだけであることを確認している。
　このように、特許文献２の製造法で、金属Ｓｉを含まない非結晶質のＳｉＯＸを製造することは、かなり非現実的であることが判った。 In addition, in a plasma flame at 10,000 ° C. of an RF (radio frequency induction) thermal plasma apparatus having a very slow plasma flame speed, a metal Si powder having a smaller average particle diameter D 50 of 20 μm is obtained in an amount of 30 g / It has been confirmed that even when the operation is performed with a small supply amount of min, metal Si is not vaporized and is simply recovered as molten spheroidized particles.
As described above, it has been found that it is quite unrealistic to produce amorphous SiO X containing no metal Si by the production method of Patent Document 2.
　本発明は、上述する問題点を解決するためになされたもので、その目的は、リチウムイオン二次電池の負極活物質及びガスバリアフィルムの蒸着材料として用いられるＳｉＯＸ粉末を連続的に安価に製造することができるＳｉＯＸ粉末製造法及びＳｉＯＸ粉末製造装置を提供することにある。 The present invention has been made in order to solve the above-described problems, and its purpose is to continuously and inexpensively produce SiO X powder used as a negative electrode active material of a lithium ion secondary battery and a vapor deposition material of a gas barrier film. and to provide a SiO X powder preparation and SiO X powder production apparatus capable of.
　本発明のＳｉＯＸ粉末製造法は、金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末をプラズマ炎で加熱溶融させる工程と、加熱溶融された混合造粒粉末の溶融液滴を加熱炉で気化させてＳｉＯＸ化反応を行わせる工程と、生成されたＳｉＯＸガスを不活性ガスで急冷却してＳｉＯＸ微粉末を析出させる工程とを有する。
　また、本発明のＳｉＯＸ粉末製造装置は、プラズマ炎を噴出するプラズマガンを備えるＤＣ（直流）プラズマ装置又はＲＦ（高周波誘導）熱プラズマ装置と、金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末をプラズマ炎中に噴霧する粉末供給装置と、プラズマ炎にて加熱溶融された混合造粒粉末の溶融液滴を気化させてＳｉＯＸ化反応を行わせる加熱炉と、生成されたＳｉＯＸガスを不活性ガスで急冷却してＳｉＯＸ微粉末を析出させる冷却装置とを有する。 The SiO X powder production method of the present invention includes a step of heating and melting a mixed granulated powder of metal Si powder and SiO 2 powder with a plasma flame, and vaporizing molten droplets of the heated and melted mixed granulated powder in a heating furnace. And a step of causing the SiO X reaction to be performed, and a step of rapidly cooling the generated SiO X gas with an inert gas to precipitate SiO X fine powder.
Moreover, the SiO X powder production apparatus of the present invention is a mixed granulation of a DC (direct current) plasma apparatus or an RF (high frequency induction) thermal plasma apparatus equipped with a plasma gun for ejecting a plasma flame, and a metal Si powder and SiO 2 powder. Powder supply device for spraying powder into plasma flame, heating furnace for vaporizing molten droplets of mixed granulated powder heated and melted in plasma flame to perform SiO X conversion reaction, and generated SiO X gas And a cooling device for precipitating SiO X fine powder by rapid cooling with an inert gas.
　本発明は、金属Ｓｉ粉末原料に高純度（４Ｎ以上）Ｓｉ粉末を用いる。高純度（４Ｎ以上）Ｓｉ粉末は、例えば、半導体や太陽電池用等のシリコンウエーハ製造工程で発生する金属Ｓｉスラッジを高純度（４Ｎ以上）に再生して使用する。
　元々、半導体や太陽電池用等に用いられる金属Ｓｉは、非常に高純度に精製されたものである。しかし、シリコンウエーハのスライス、研磨工程で発生した粉末は、非常に微粒子で扱いにくく、不純物に汚染されたスラッジとして回収され、廃棄物としてコストをかけて処理されている。 In the present invention, high purity (4N or more) Si powder is used as a metal Si powder raw material. The high-purity (4N or higher) Si powder is used by regenerating metal Si sludge generated in a silicon wafer manufacturing process such as for semiconductors and solar cells to a high purity (4N or higher).
Originally, metal Si used for semiconductors, solar cells and the like has been purified to a very high purity. However, the powder generated in the silicon wafer slicing and polishing process is very difficult to handle with fine particles, collected as sludge contaminated with impurities, and processed as waste as cost.
　本発明は、金属Ｓｉ粉末とＳｉＯ２粉末とが、それぞれの平均粒子径Ｄ５０が１０μｍ以下、好ましくは平均粒子径Ｄ５０が５μｍ以下の金属Ｓｉ粉末とＳｉＯ２粉末とを使用し、ＳｉＯＸのＸ値が０．５～１．８になるように金属Ｓｉ粉末とＳｉＯ２粉末との混合比率を設定する。
　本発明は、これらの混合粉末原料に水、溶剤、分散剤、バインダーを混ぜて、ミキサーにて十分に撹拌混合し、スラリー化したものを噴霧乾燥法（スプレードライ）で平均粒子径Ｄ５０を１０μｍ～５０μｍに造粒した金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末を使用することが好ましい。 The present invention is a metal Si powder and SiO 2 powder, each having an average particle diameter D 50 of 10μm or less, preferably have an average particle diameter D 50 using the following metal Si powder and SiO 2 powder 5 [mu] m, SiO X The mixing ratio of the metal Si powder and the SiO 2 powder is set so that the X value of is 0.5 to 1.8.
The present invention, water in these mixed powder materials, solvent, dispersing agent, by mixing a binder, well stirred mixture by a mixer, spray drying method obtained by slurrying the average particle diameter D 50 at (spray-dried) It is preferable to use a mixed granulated powder of metal Si powder and SiO 2 powder granulated to 10 μm to 50 μm.
　また、金属Ｓｉ粉末とＳｉＯ２粉末とを一定比率で均一混合造粒し、その原料を二次原料として使用する。金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒であるこの二次原料は、微粉体同士の反応性を高め、プラズマ炎内での金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末の溶融と気化とに大きな効果を発揮する。しかも、金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末の粒子内には金属Ｓｉ粉末とＳｉＯ２粉末とが一定比率で存在するため、ＳｉＯＸガスのＸ値が非常に安定した原子比の組成に容易にすることができる。 Further, the metal Si powder and the SiO 2 powder are uniformly mixed and granulated at a constant ratio, and the raw material is used as a secondary raw material. This secondary raw material, which is a mixed granulation of metal Si powder and SiO 2 powder, enhances the reactivity between fine powders, and melts the mixed granulated powder of metal Si powder and SiO 2 powder in the plasma flame. It has a great effect on vaporization. In addition, since the metal Si powder and the SiO 2 powder are present in a certain ratio in the particles of the mixed granulated powder of the metal Si powder and the SiO 2 powder, the X value of the SiO X gas has an extremely stable atomic ratio. Easy to composition.
　本発明は、プラズマ炎を発生する装置に、ＤＣ（直流）プラズマ装置又はＲＦ（高周波誘導）熱プラズマ装置を使用し、６，０００Ｋ（５，７２７℃）以上のプラズマ炎に金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末を吹き込み加熱溶融（一部は気化する）させる。このとき、プラズマ炎の中での材料飛翔速度が１５０ｍ／ｓｅｃ～３ｍ／ｓｅｃになるようにプラズマガンのノズル径を調整することが好ましい。
　通常、ＤＣ（直流）プラズマ装置は、プラズマ炎であるフレームの速度が高速であることが特徴である。ＤＣ（直流）プラズマ装置は、プラズマ溶射のようなマッハ２レベルのプラズマジェットに高融点のセラミックス粉末を投入し、材料を瞬時に溶融させて高速で基材に溶着させることにより、高密着力の被膜を形成するのに汎用的に用いられている。 The present invention uses a DC (direct current) plasma device or an RF (radio frequency induction) thermal plasma device as a device for generating a plasma flame, and a metal Si powder and SiO for a plasma flame of 6,000 K (5,727 ° C.) or more. The mixed granulated powder with 2 powders is blown and melted by heating (partially vaporized). At this time, it is preferable to adjust the nozzle diameter of the plasma gun so that the material flight speed in the plasma flame is 150 m / sec to 3 m / sec.
In general, a DC (direct current) plasma apparatus is characterized by a high speed flame that is a plasma flame. A DC (direct current) plasma device is a high-adhesion coating film that is made by introducing a high melting point ceramic powder into a Mach 2 level plasma jet such as plasma spraying, instantly melting the material and welding it to the substrate at high speed. Is generally used to form
　しかし、ＤＣ（直流）プラズマ装置は、本発明のように金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末を原料にして、この混合造粒粉末を加熱溶融（一部は気化する）させるためには、フレームの速度が速すぎる。そのため、金属Ｓｉのように溶融熱及び気化熱の大きな材料は、溶融はしても気化するには熱量、反応時間の面から不十分である。
　故に、ＤＣ（直流）プラズマ装置は、プラズマガン先端部のノズル径を大きくして、プラズマ炎の中での材料飛翔速度を１５０ｍ／ｓｅｃ以下にすることにより、反応時間を長くして溶融と気化及び化学反応を促進させる特殊な構造とする。 However, the DC (direct current) plasma apparatus uses the mixed granulated powder of the metal Si powder and the SiO 2 powder as a raw material and heats and melts (partially vaporizes) the mixed granulated powder as in the present invention. The frame speed is too fast. For this reason, a material having a large heat of fusion and heat of vaporization, such as metal Si, is insufficient in terms of heat amount and reaction time for vaporization even if it is melted.
Therefore, the DC (direct current) plasma device increases the nozzle diameter at the tip of the plasma gun and makes the material flight speed in the plasma flame 150 m / sec or less, thereby increasing the reaction time and melting and vaporizing. And a special structure that promotes chemical reactions.
　ところで、プラズマ装置を使用しても、金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末の全てを溶融し気化することは難しい。
　そこで、本発明では、気化しない金属ＳｉとＳｉＯ２粉末とを完全にガス化させ、合成反応させるためにプラズマガンの前方に加熱炉を設置する。
　加熱炉には、黒鉛ヒーター加熱炉又は高周波誘導加熱炉を使用し、反応管には高耐熱性の黒鉛管を使用して黒鉛管の周囲は断熱し、更に水冷却する。プラズマ炎で溶融した液滴を更に黒鉛管内温度を２，０００Ｋ（１，７２７℃）以上に維持して加熱し気化させて、完全にＳｉＯＸガスを生成させる。すなわち、プラズマ炎で溶融した液滴の全てがガス化することにより、生成されるＳｉＯＸは均一な組成となる。
　リチウムイオン二次電池の負極活物質としてのＳｉＯＸもガスバリアフィルム用蒸着材としてのＳｉＯＸも、気化せずに未反応な金属ＳｉとＳｉＯ２とが残ると、負極電極の充放電特性の悪化やガスバリア特性の悪化につながる。 By the way, even if the plasma apparatus is used, it is difficult to melt and vaporize all of the mixed granulated powder of the metal Si powder and the SiO 2 powder.
Therefore, in the present invention, a heating furnace is installed in front of the plasma gun in order to completely gasify the metal Si that is not vaporized and the SiO 2 powder to cause a synthetic reaction.
A graphite heater heating furnace or a high-frequency induction heating furnace is used as the heating furnace, a highly heat-resistant graphite pipe is used as the reaction tube, the periphery of the graphite tube is insulated, and further water-cooled. The droplet melted by the plasma flame is further heated and vaporized while maintaining the temperature in the graphite tube at 2,000 K (1,727 ° C.) or higher, thereby completely generating SiO X gas. That is, all of the droplets melted by the plasma flame are gasified, so that the generated SiO X has a uniform composition.
Also SiO X as SiO X also gas barrier film for vapor deposition material as a negative electrode active material of a lithium ion secondary battery, when without vaporizing unreacted metal Si and SiO 2 remains, deterioration in charge-discharge characteristics of the negative electrode And lead to deterioration of gas barrier properties.
　次に、本発明では、加熱炉の出口に、Ｎ２、Ａｒ等の圧縮不活性ガスをリング状ノズルから噴出混合して、高温度ＳｉＯＸガスを８００℃以下に急冷却し、０．０１μｍ～１０μｍのＳｉＯＸ微粉末を析出させる冷却装置を備える。
　加熱炉の反応管内で生成される２，０００Ｋ（１，７２７℃）以上の高温度ＳｉＯＸガスは、加熱炉の出口に備えた冷却装置のリング状ノズルから噴出されるＮ２、Ａｒ等の圧縮不活性ガスにより８００℃以下に急冷却されることで、ＳｉＯＸの組成のままでアモルファス状のＳｉＯＸ微粉末として析出させることができる。
　もし、高温度のＳｉＯＸガスのみを直接水冷チャンバーの雰囲気中に噴出させると、一部のＳｉＯＸガスが徐冷され、管体の内壁面に析出して固化し、ＳｉＯＸの一部は不均化反応により再度金属Ｓｉ粉末とＳｉＯ２粉末とに分離し、ＳｉＯＸの組成の収率が下がる。
　圧縮不活性ガスは、Ｎ２を用いることが冷却効率も良く、且つコスト的にも安価で好ましい。 Next, in the present invention, a compressed inert gas such as N 2 or Ar is jetted and mixed from the ring-shaped nozzle at the outlet of the heating furnace, and the high-temperature SiO X gas is rapidly cooled to 800 ° C. or less to 0.01 μm A cooling device for precipitating ˜10 μm SiO X fine powder is provided.
High-temperature SiO X gas of 2,000 K (1,727 ° C.) or more generated in the reaction tube of the heating furnace is N 2 , Ar, or the like ejected from the ring-shaped nozzle of the cooling device provided at the outlet of the heating furnace. by being suddenly cooled to 800 ° C. below the compressed inert gas, can be precipitated as an amorphous SiO X fine powder remains in the composition of the SiO X.
If the jetted in the atmosphere directly water-cooled chamber only SiO X gas high temperature, it is slowly cooled part of the SiO X gas, and solidified deposited on the inner wall surface of the tubular body, a portion of the SiO X By the disproportionation reaction, the metal Si powder and the SiO 2 powder are separated again, and the yield of the composition of SiO X is lowered.
As the compressed inert gas, it is preferable to use N 2 because the cooling efficiency is good and the cost is low.
　また、本発明は、加熱炉内を３０ｋＰａ～８０ｋＰａの減圧下で操業することが好ましい。
　加熱炉の反応管内は、３０ｋＰａ～８０ｋＰａの減圧下で操業することにより、金属Ｓｉ粉末とＳｉＯ２粉末との反応温度を下げ、ＳｉＯ化反応をより促進させることができる。この減圧操業は絶対必要条件ではなく、減圧設備は投資とその効果で適宜判断すればよい。
　３０ｋＰａ～８０ｋＰａの減圧の程度は特にこれに限定されるものでなく、供給材料（造粒粉末）の粒子径、供給量、プラズマ装置の出力、加熱炉の温度等、様々な操業条件によって、最適条件を設定すればよく、この減圧操業を付加することにより、更に操業の自由度を上げることができる。
　３０ｋＰａ未満では、設備費が高くなり、８０ｋＰａを超えると減圧操業の効果があまり期待できない。 In the present invention, the inside of the heating furnace is preferably operated under a reduced pressure of 30 kPa to 80 kPa.
By operating the inside of the reaction tube of the heating furnace under a reduced pressure of 30 kPa to 80 kPa, the reaction temperature between the metal Si powder and the SiO 2 powder can be lowered and the SiO conversion reaction can be further promoted. This decompression operation is not an absolute requirement, and the decompression facility may be appropriately determined based on the investment and its effect.
The degree of pressure reduction of 30 kPa to 80 kPa is not particularly limited, and is optimal depending on various operating conditions such as the particle diameter of the feed material (granulated powder), the supply amount, the output of the plasma apparatus, the temperature of the heating furnace, etc. It is only necessary to set conditions, and by adding this decompression operation, the degree of freedom of operation can be further increased.
If it is less than 30 kPa, the equipment cost becomes high, and if it exceeds 80 kPa, the effect of decompression operation cannot be expected so much.
　本発明は、析出した０．０１μｍ～１０μｍのＳｉＯＸ微粉末を水冷却サイクロンにて冷却することで、平均粒子径Ｄ５０を１μｍ～２０μｍの微粉末に成長或いは凝集させて回収することが好ましい。
　Ｎ２、Ａｒ等の圧縮不活性ガスによる冷却で生成されたＳｉＯＸ粉末は、粒子径が細かすぎて回収効率が悪いが、水冷却サイクロンで粒子径を成長させることでＳｉＯＸ粉末の回収率を上げる効果がある。
　水冷却サイクロンは、外周が水冷却されており、８００℃以下に一次冷却されたＳｉＯＸ微粉末及びＮ２、Ａｒ等の圧縮不活性ガスが円周方向に高流速で吹き込まれることで、吹き込まれたＳｉＯＸ微粉末が２００℃以下に冷却されて、粒子径を成長或いは凝集させる。大半のＳｉＯＸ微粉末を水冷却サイクロン内で回収することが好ましい。回収されたＳｉＯＸ微粉末の平均粒子径Ｄ５０を１μｍ～２０μｍとすることで、リチウムイオン二次電池の負極活物質として使う場合に、微粉砕工程等を通す必要がなく、大幅なコスト低減効果がある。 In the present invention, it is preferable that the precipitated SiO X fine powder of 0.01 μm to 10 μm is cooled with a water-cooled cyclone so that the average particle diameter D 50 grows or aggregates into a fine powder of 1 μm to 20 μm and is collected. .
The SiO X powder produced by cooling with a compressed inert gas such as N 2 and Ar has a particle size that is too fine and poor in recovery efficiency. However, the recovery rate of the SiO X powder is obtained by growing the particle diameter in a water-cooled cyclone. There is an effect to raise.
The water-cooled cyclone has an outer periphery that is water-cooled, and is blown by a high-flow rate of compressed inert gas such as SiO X fine powder and N 2 , Ar that has been primarily cooled to 800 ° C. or less. The resulting SiO X fine powder is cooled to 200 ° C. or lower to grow or aggregate the particle diameter. It is preferred to recover most of the SiO X fine powder in a water-cooled cyclone. The average particle diameter D 50 of the recovered SiO X fine powder by a 1 [mu] m ~ 20 [mu] m, when used as the negative electrode active material of a lithium ion secondary battery, it is not necessary to pass the milling step or the like, significant cost reduction effective.
　また、本発明は、水冷却サイクロンで未回収の超微粉をバグフィルタで回収集塵することが好ましい。
　水冷却サイクロンでは、サブミクロン（１μｍ以下）以下のＳｉＯＸ微粒子が完全に回収できないため、これらの微粒子をバグフィルタにて完全除去して、排気ガスはクリーンな状態にして大気に排出する。
また、本発明は、水冷却サイクロンで未回収の超微粉をバグフィルタで回収集塵後のクリーンな排気ガスであるＮ２、Ａｒガスを熱交換器で常温まで冷却し、更に高圧ブロワーにて昇圧し、不活性ガス冷却装置を通して循環使用する。これにより、冷却用の新しいＮ２、Ａｒガスは、稼働初期の系内ガスパージ時のみ使用し、その後は排気ガスを循環使用することにより、大幅なコスト低減が図れる。
　なお、本明細書において、「平均粒子径Ｄ５０」は、レーザー回折・散乱法によって求めた粒子径分布における積算値５０％での粒子径を意味する。 Further, in the present invention, it is preferable to collect uncollected ultra fine powder by a bag filter using a water cooling cyclone.
In the water-cooled cyclone, SiO X fine particles of submicron (1 μm or less) or less cannot be completely recovered. Therefore, these fine particles are completely removed by a bag filter, and the exhaust gas is discharged into the atmosphere in a clean state.
In addition, the present invention is to cool N 2 and Ar gas, which are clean exhaust gas after dust collected by a bag filter, with a water-cooled cyclone, to a room temperature with a heat exchanger, and further with a high-pressure blower. Pressurize and circulate through an inert gas cooler. Thus, new N 2 and Ar gases for cooling are used only at the time of in-system gas purging at the initial stage of operation, and thereafter, exhaust gas is circulated and used, so that a significant cost reduction can be achieved.
In the present specification, “average particle diameter D 50 ” means a particle diameter at an integrated value of 50% in a particle diameter distribution determined by a laser diffraction / scattering method.
　本発明によれば、リチウムイオン吸蔵容量が大きく、且つ、充放電による活物質コーティング被膜の体積膨張収縮が小さく、充放電サイクル特性に優れたＳｉＯＸ系活物質を、Ｘ値を任意にコントロールし、また粉砕工程を通すことなく最適な粒子径で、連続的に安価に製造することができる。 According to the present invention, a SiO X- based active material having a large lithium ion storage capacity, a small volume expansion / contraction shrinkage of the active material coating film due to charge / discharge, and excellent charge / discharge cycle characteristics can be controlled arbitrarily. In addition, it can be continuously produced at a low cost with an optimum particle size without going through a pulverization step.
　本発明によれば、半導体や太陽電池用等のシリコンウエーハ製造工程で発生する金属Ｓｉスラッジ（廃棄物スラッジ）を高純度（４Ｎ以上）に再生して使用するので、環境対策にも優れている。
　また、この廃棄物スラッジは、高純度化のための再生を安価にできるため、原料コストを低く抑えることができるという利点がある。
　また、この廃棄物スラッジは、プラズマ装置で使用する投入原料である造粒粉として既に造粒目的に合った最適な粒子径分布をしており、微粉化のための粉砕工程を省略でき、非常に大きなコスト低減になる。 According to the present invention, metal Si sludge (waste sludge) generated in a silicon wafer manufacturing process for semiconductors, solar cells, etc. is regenerated to high purity (4N or more) and is therefore excellent in environmental measures. .
Moreover, since this waste sludge can be regenerated for high purity at low cost, there is an advantage that raw material costs can be kept low.
In addition, this waste sludge has already had an optimal particle size distribution suitable for the purpose of granulation as a granulated powder that is a raw material used in the plasma apparatus, and the pulverization process for pulverization can be omitted. This greatly reduces costs.
　本発明によれば、プラズマ炎で加熱溶融（一部は気化する）された混合造粒粉末の溶融液滴を加熱炉で気化させてＳｉＯＸ化反応を行わせ、ＳｉＯＸガスを生成させるので、全てがガス化し、生成されるＳｉＯＸは均一な組成となる。
　このため、未反応な金属Ｓｉが残り、リチウムイオン二次電池における充放電特性の悪化やガスバリア特性の悪化を招くという従来の問題点を解決することができるとともに、ＳｉＯＸの回収歩留まりも高くなる。 According to the present invention, the molten droplets of the mixed granulated powder heated and melted (partially vaporized) by the plasma flame are vaporized in the heating furnace to cause the SiO X conversion reaction, thereby generating the SiO X gas. All are gasified, and the resulting SiO X has a uniform composition.
For this reason, unreacted metal Si remains, so that it is possible to solve the conventional problem that the charge / discharge characteristics and gas barrier characteristics of the lithium ion secondary battery are deteriorated, and the recovery yield of SiO X is increased. .
　本発明によれば、金属Ｓｉ粉末とＳｉＯ２粉末とを造粒して平均粒子径Ｄ５０を１０μｍ～５０μｍの混合造粒粉末とするので、通常の溶射設備で汎用的に使用されている材料供給装置で安定して材料供給することができる。従って、従来の粉末供給装置のように、粒子径が細かくなればなるほど非常に供給量が不安定となり、安定して均一な混合比のものを製造しにくいという問題や、特殊な材料供給装置が必要になるという不具合を解消することができる。 According to the present invention, the metal Si powder and the SiO 2 powder are granulated to obtain a mixed granulated powder having an average particle diameter D 50 of 10 μm to 50 μm. The material can be supplied stably with the supply device. Therefore, as in the conventional powder supply device, the smaller the particle diameter, the more unstable the supply amount, and it is difficult to produce a stable and uniform mixing ratio, and there is a special material supply device. The problem of being necessary can be solved.
　本発明によれば、加熱炉で生成される２，０００Ｋ（１，７２７℃）以上の高温度のＳｉＯＸガスを、加熱炉の出口に冷却装置を備えてＮ２、Ａｒ等の圧縮不活性ガスをリング状ノズルから噴出混合して、８００℃以下に急冷却し、ＳｉＯＸ微粉末を析出させるので、ＳｉＯＸの組成のままで、アモルファス状のＳｉＯＸ微粒子を析出させることができる。
　この際、圧縮不活性ガスにＮ２を用いると、冷却効率が良いばかりか、コスト的にも安価で好ましい。 According to the present invention, a high temperature SiO X gas of 2,000 K (1,727 ° C.) or higher generated in a heating furnace is provided with a cooling device at the outlet of the heating furnace, and is compressed inactive such as N 2 and Ar. gas ejected mixture from the ring-shaped nozzle, rapidly cooled to 800 ° C. or less, since the precipitating SiO X fine powder can remain composition SiO X, to deposit the amorphous SiO X microparticles.
At this time, it is preferable to use N 2 for the compressed inert gas because the cooling efficiency is good and the cost is low.
　本発明によれば、加熱炉内を３０ｋＰａ～８０ｋＰａの減圧下で操業するので、金属Ｓｉ粉末とＳｉＯ２粉末との混合溶融液滴の気化温度を下げ、ＳｉＯＸ化反応をより促進させることができる。 According to the present invention, since the inside of the heating furnace is operated under a reduced pressure of 30 kPa to 80 kPa, it is possible to lower the vaporization temperature of the mixed molten droplets of the metal Si powder and the SiO 2 powder and further promote the SiO X conversion reaction. it can.
　本発明によれば、８００℃以下に一次冷却されたＳｉＯＸ微粉末及びＮ２、Ａｒ等の圧縮不活性ガスを水冷却サイクロンに円周方向に高流速で吹き込むので、ＳｉＯＸ微粉末が２００℃以下に冷却されて、粒子径が成長或いは凝集するので、大半のＳｉＯＸ微粉末を水冷却サイクロン内で回収することができる。また、回収されるＳｉＯＸ微粉末の平均粒子径Ｄ５０を、１μｍ～２０μｍとすることができる。
　本発明によれば、回収されるＳｉＯＸ微粉末の平均粒子径Ｄ５０を１μｍ～２０μｍとすることで、リチウムイオン二次電池の負極活物質として使う場合に、微粉砕工程等を通す必要がなく、大幅なコスト低減効果がある。 According to the present invention, since blowing SiO X powder and N 2, compressed inert gas such as Ar that has been primary cooling to 800 ° C. or less at a high flow rate circumferentially of water cooling cyclone, SiO X fine powder 200 Since the particle diameter grows or aggregates when cooled to below ℃, most of the SiO X fine powder can be recovered in a water-cooled cyclone. Further, the average particle diameter D 50 of the recovered SiO X fine powder can be set to 1 μm to 20 μm.
According to the present invention, when the average particle diameter D 50 of the recovered SiO X fine powder is 1 μm to 20 μm, it is necessary to go through a fine pulverization step or the like when used as a negative electrode active material of a lithium ion secondary battery. There is no significant cost reduction effect.
　本発明によれば、水冷却サイクロンでは完全に回収できないサブミクロン（１μｍ以下）以下のＳｉＯＸ微粒子をバグフィルタにて完全除去し、排気ガスはクリーンな状態にして大気に排出することができる。
また、本発明によれば、バグフィルタでＳｉＯＸ微粒子を回収集塵後のクリーンな排気ガスを熱交換器で常温に冷却後に高圧ブロワーにて昇圧し、冷却装置に循環使用することにより、大幅なコスト低減が可能である。
バグフィルタ後のクリーンな排気ガスを循環使用する場合は、プラズマガンで吹込まれた作動ガス（Ｎ２、Ａｒガス等）相当が余剰ガスとして大気放出される。
なお、どこまで不活性ガスを循環使用するかは、バグフィルタ後の排気ガスの清浄度により、そのための設備費とランニングコストで判断すればよい。 According to the present invention, submicron (1 μm or less) SiO X fine particles that cannot be completely recovered by a water-cooled cyclone can be completely removed by a bag filter, and the exhaust gas can be discharged into the atmosphere in a clean state.
In addition, according to the present invention, clean exhaust gas after collecting and collecting SiO X particulates with a bag filter is cooled to room temperature with a heat exchanger, then boosted with a high-pressure blower, and recycled to the cooling device. Cost reduction is possible.
When the clean exhaust gas after the bag filter is circulated and used, the working gas (N 2 , Ar gas, etc.) blown by the plasma gun is released into the atmosphere as surplus gas.
It should be noted that the extent to which the inert gas is circulated and used can be determined by the equipment cost and the running cost for the exhaust gas after the bag filter is clean.
本発明に係るＳｉＯＸ粉末製造法の第一実施態様に使用するＳｉＯＸ粉末製造装置の断面構造を模式的に示す図である。The cross-sectional structure of the SiO X powder production apparatus used in the first embodiment of the SiO X powder production method according to the present invention is a diagram schematically showing. 図１におけるＤＣプラズマガン先端部の断面構造を示す模式図である。It is a schematic diagram which shows the cross-sectional structure of the DC plasma gun front-end | tip part in FIG. 図１における圧縮Ｎ２ガスによる冷却を行う冷却装置の断面構造を示す図である。It is a diagram showing a sectional structure of a cooling device for cooling by compressed N 2 gas in FIG. 本発明に係るＳｉＯＸ粉末製造法の第二実施態様に使用するＳｉＯＸ粉末製造装置の断面構造を模式的に示す図である。The cross-sectional structure of the SiO X powder production apparatus used in the second embodiment of the SiO X powder production method according to the present invention is a diagram schematically showing. 図４における圧縮Ｎ２ガスによる冷却を行う冷却装置の断面構造を示す図である。It is a diagram showing a sectional structure of a cooling device for cooling by compressed N 2 gas in FIG.
　（第一実施形態）
　本発明の第一実施形態を図面に基づいて説明する。
　図１～図３は、本実施形態のＳｉＯＸ粉末製造法を構成する工程（Ａ）～（Ｅ）及びそれに用いられるＳｉＯＸ粉末製造装置を示す。 (First embodiment)
A first embodiment of the present invention will be described with reference to the drawings.
1 to 3 show the steps (A) to (E) constituting the SiO X powder manufacturing method of the present embodiment and the SiO X powder manufacturing apparatus used therefor.
　先ず、本実施形態のＳｉＯＸ粉末製造法を工程（Ａ）～（Ｅ）に基づいて説明する。
　工程（Ａ）では、ＤＣ（直流）プラズマ装置１を作動して、プラズマガン２から噴出するプラズマ炎３に、粉末供給ノズル４から金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末５を供給し、混合造粒粉末５を加熱溶融（一部は気化する）させる。
　混合造粒粉末５は、粉末造粒装置１３で金属Ｓｉ粉末とＳｉＯ２粉末とを混合して造粒され、次いで、粉末供給装置１４を介してプラズマガン先端部２ａの近傍に配置した粉末供給ノズル４からプラズマ炎３に供給される。 First, the SiO X powder manufacturing method of the present embodiment will be described based on the steps (A) to (E).
In the step (A), the DC (direct current) plasma apparatus 1 is operated to supply the mixed granulated powder 5 of the metal Si powder and the SiO 2 powder from the powder supply nozzle 4 to the plasma flame 3 ejected from the plasma gun 2. Then, the mixed granulated powder 5 is heated and melted (partially vaporized).
The mixed granulated powder 5 is granulated by mixing the metal Si powder and the SiO 2 powder in the powder granulator 13, and then the powder supply disposed near the plasma gun tip 2 a via the powder feeder 14. It is supplied from the nozzle 4 to the plasma flame 3.
　次に、工程（Ｂ）では、工程（Ａ）において加熱溶融（一部は気化する）された混合造粒粉末５の溶融液滴を高周波誘導加熱炉１９の黒鉛管（反応管）１５内で高温にて気化させてＳｉＯＸ化反応を行わせる。
　次に、工程（Ｃ）では、工程（Ｂ）において生成されたＳｉＯＸガスをガス冷却装置２０でＮ２、Ａｒ等の圧縮不活性ガスを用いて急冷却してＳｉＯＸ微粉末２５ａを析出させる。
　次に、工程（Ｄ）では、工程（Ｃ）において析出したＳｉＯＸ微粉末２５ａを水冷却サイクロン２４にて冷却して成長或いは凝集した微粉末状のＳｉＯＸ粉末２５ｂとして回収する。
　次に、工程（Ｅ）では、水冷却サイクロン２４で未回収の超微粉をバグフィルタ２７で回収集塵する。
  以上によって、リチウムイオン二次電池の負極活物質及びガスバリアフィルムの蒸着材料として用いられるＳｉＯＸ微粉末を得ることができる。 Next, in the step (B), the molten droplets of the mixed granulated powder 5 that has been heated and melted (partially vaporized) in the step (A) are placed in the graphite tube (reaction tube) 15 of the high-frequency induction heating furnace 19. It is vaporized at a high temperature to cause the SiO X conversion reaction.
Next, in the step (C), the SiO X gas generated in the step (B) is rapidly cooled using a compressed inert gas such as N 2 or Ar in the gas cooling device 20 to precipitate the SiO X fine powder 25a. Let
Next, in the step (D), the SiO X fine powder 25a deposited in the step (C) is cooled by the water-cooled cyclone 24 and recovered as a fine powdery SiO X powder 25b grown or aggregated.
Next, in the step (E), uncollected ultrafine powder is collected by the bag filter 27 by the water cooling cyclone 24 and collected.
Above, it is possible to obtain a SiO X fine powder used as a vapor deposition material of the negative electrode active material and the gas barrier film of the lithium ion secondary battery.
　次に、本実施形態のＳｉＯX粉末製造装置を説明する。
　図１～図３に示すように、本実施形態のＳｉＯX粉末製造装置は、プラズマ炎３を噴出するプラズマガン２を備えるＤＣ（直流）プラズマ装置１を有する。ＤＣ（直流）プラズマ装置１から噴出するプラズマ炎３中に、金属Ｓｉ粉末とＳｉＯ2粉末との混合造粒粉末５を噴霧する粉末供給ノズル４が、プラズマガン先端部２ａの近傍に配置される。
　ＤＣ（直流）プラズマ装置１の前方に、ＤＣ（直流）プラズマ装置１から噴出されるプラズマ炎３にて加熱溶融（一部は気化する）された混合造粒粉末５の溶融液滴を気化させてＳｉＯX化反応を行わせる高周波誘導加熱炉１９を配置する。
　高周波誘導加熱炉１９の出口に、高周波誘導加熱炉１９で生成されたＳｉＯXガスを不活性ガスで急冷却してＳｉＯX微粉末２５ａを析出させる冷却装置２０を配置する。
　冷却装置２０の出口に、冷却装置２０で析出したＳｉＯX微粉末２５ａを冷却して成長或いは凝集した微粉末状のＳｉＯX粉末２５ｂとして回収する水冷却サイクロン２４を配置する。
　水冷却サイクロン２４の下流側に、水冷却サイクロン２４で未回収のＳｉＯX微粉末を回収集塵するバグフィルタ２７を配置する。 Next, the SiO X powder manufacturing apparatus of this embodiment will be described.
As shown in FIGS. 1 to 3, the SiO X powder manufacturing apparatus of the present embodiment includes a DC (direct current) plasma apparatus 1 including a plasma gun 2 that ejects a plasma flame 3. A powder supply nozzle 4 for spraying a mixed granulated powder 5 of a metal Si powder and a SiO 2 powder in a plasma flame 3 ejected from a DC (direct current) plasma apparatus 1 is arranged in the vicinity of the plasma gun tip 2a. .
In front of the DC (direct current) plasma apparatus 1, the molten droplets of the mixed granulated powder 5 that is heated and melted (partially vaporized) by the plasma flame 3 ejected from the DC (direct current) plasma apparatus 1 are vaporized. Then, a high frequency induction heating furnace 19 for performing the SiO x conversion reaction is disposed.
At the outlet of the high-frequency induction heating furnace 19, a cooling device 20 is disposed that rapidly cools the SiO x gas generated in the high-frequency induction heating furnace 19 with an inert gas to precipitate the SiO x fine powder 25a.
At the outlet of the cooling device 20, a water-cooled cyclone 24 that cools the SiO X fine powder 25 a deposited by the cooling device 20 and collects it as a fine powdery SiO X powder 25 b grown or aggregated is disposed.
On the downstream side of the water-cooled cyclone 24, a bag filter 27 for collecting and collecting uncollected SiO x fine powder by the water-cooled cyclone 24 is disposed.
　次に、工程（Ａ）について、詳細に説明する。
　本実施形態では、工程（Ａ）の金属Ｓｉ粉末とＳｉＯ2粉末との混合造粒粉末５で使用される金属Ｓｉ粉末に、半導体又は太陽電池用シリコンウエーハ製造工程で発生した金属Ｓｉスラッジを再生して使用する。
　この場合、金属Ｓｉスラッジの発生場所により、粉末粒子径、不純物含有量、水分含有量等が様々であるため、その性状によって事前処理して金属Ｓｉ粉末に精製する。
　その精製法には、不純物除去、脱水、凝集粉の解砕、乾燥等それぞれの工程で様々な方法があり、特に限定するものではない。 Next, the step (A) will be described in detail.
In the present embodiment, the metal Si sludge generated in the semiconductor or solar cell silicon wafer manufacturing process is regenerated into the metal Si powder used in the mixed granulated powder 5 of the metal Si powder and the SiO 2 powder in the step (A). And use it.
In this case, since the powder particle diameter, impurity content, moisture content, and the like vary depending on the location where the metal Si sludge is generated, it is pretreated according to its properties and refined into metal Si powder.
There are various purification methods, such as impurity removal, dehydration, pulverization of agglomerated powder, and drying, and the method is not particularly limited.
　金属Ｓｉ粉末とＳｉＯ２粉末とは、平均粒子径Ｄ５０が１０μｍ以下、より好ましくは、平均粒子径Ｄ５０が５μｍ以下のものを使用する。
　それぞれの平均粒子径Ｄ５０が１０μｍを超えると、造粒した際の１粒子内の金属Ｓｉ粉末とＳｉＯ２粉末との混合比率のバラツキが大きくなる。また、プラズマ炎３に吹き込まれて溶融液滴化する際の金属Ｓｉ粉末とＳｉＯ２粒子との接触界面の表面積が小さくなり、金属ＳｉとＳｉＯ２との反応性を高める効果が出にくくなる。
　なお、ＳｉＯ２粉末の平均粒子径Ｄ５０の下限値は特に限定しない。しかし、金属Ｓｉ粉末は、最表面に自然酸化膜ができるが、平均粒子径Ｄ５０が１μｍ未満の微粒子になると、反応性が高く、扱うのが困難になる。そのため、金属Ｓｉ粉末の平均粒子径Ｄ５０の下限値は１μｍとする。
　金属Ｓｉ粉末とＳｉＯ２粉末との混合比率は、目的とするＳｉＯＸ粉末のＸ値が０．５～１．８になるように調整する。 As the metal Si powder and the SiO 2 powder, those having an average particle diameter D 50 of 10 μm or less, more preferably, an average particle diameter D 50 of 5 μm or less are used.
When each average particle diameter D 50 exceeds 10 μm, the variation in the mixing ratio of the metal Si powder and the SiO 2 powder in one particle when granulated increases. Further, the surface area of the contact interface between the metal Si powder and the SiO 2 particles when blown into the plasma flame 3 to form a molten droplet is reduced, and the effect of increasing the reactivity between the metal Si and SiO 2 is less likely to occur.
The lower limit of the average particle diameter D 50 of the SiO 2 powder is not particularly limited. However, the metal Si powder may natural oxide film on the outermost surface, the average particle diameter D 50 is fine particles of less than 1 [mu] m, high reactivity, it is difficult to handle. Therefore, the lower limit of the average particle diameter D 50 of the metal Si powder and 1 [mu] m.
The mixing ratio of the metal Si powder and the SiO 2 powder is adjusted so that the X value of the target SiO X powder is 0.5 to 1.8.
　リチウムイオン二次電池の負極活物質にＳｉＯＸを使用する場合、Ｘ値の大小により、リチウムイオン吸蔵容量とＳｉＯＸコーティング皮膜の充放電による体積膨張収縮による充放電サイクル特性とが反比例するため、Ｘ値は０．５～１．８の中で、最適値を選択する必要がある。
　Ｘ値が０．５未満では、リチウムイオン吸蔵容量は大きくなるが、活物質皮膜の膨張収縮による充放電サイクル特性は低下するため実用的でない。
　Ｘ値が１．８を超えると、活物質皮膜の膨張収縮はほとんど問題ないが、リチウムイオン吸蔵容量の増大があまり期待できない。 When SiO X is used as the negative electrode active material of a lithium ion secondary battery, the lithium ion storage capacity and charge / discharge cycle characteristics due to volume expansion / contraction due to charge / discharge of the SiO X coating film are inversely proportional to the magnitude of the X value. It is necessary to select an optimum value among X values of 0.5 to 1.8.
When the X value is less than 0.5, the lithium ion storage capacity increases, but the charge / discharge cycle characteristics due to the expansion and contraction of the active material film deteriorate, which is not practical.
When the X value exceeds 1.8, the expansion and contraction of the active material film has almost no problem, but an increase in the lithium ion storage capacity cannot be expected so much.
　一方、ガスバリア材としてシリカとアルミナとを比較すると、シリカの方がガスバリア性に優れ、柔軟性もあるが、黄色味を帯びるという欠点があり、アルミナは無色透明でコストも安いが堅くて脆く、ガスバリア性に劣るという欠点がある。
　シリカ蒸着膜は、ＳｉＯＸのＸ値が１．５～１．８程度の酸化状態で使われるが、Ｘ値が１．０に近づくと、ガスバリア性は上がるが黄色味を帯びる。逆に、Ｘ値が２．０に近づくと、色調は薄くなるがガスバリア性は落ちるという問題があり、酸化度の制御が重要になる。このようにガスバリア性をとるか、フィルムの透明度をとるかによってＸ値をいくらにするかはフィルムの用途によって使い分けられる。 On the other hand, when silica and alumina are compared as a gas barrier material, silica has better gas barrier properties and flexibility, but has the disadvantage of being yellowish, and alumina is colorless and transparent and cheap, but hard and brittle. There is a disadvantage that the gas barrier property is inferior.
The silica deposited film is used in an oxidized state where the X value of SiO X is about 1.5 to 1.8. When the X value approaches 1.0, the gas barrier property is increased, but it becomes yellowish. On the contrary, when the X value approaches 2.0, there is a problem that the color tone becomes thin but the gas barrier property is lowered, and the control of the degree of oxidation becomes important. Thus, the X value can be selected depending on the use of the film depending on whether the gas barrier property is taken or the transparency of the film is taken.
　大切なことは、金属Ｓｉを含まず、ガスバリア材の場合のＸ値は１．５～１．８、リチウムイオン二次電池の負極活物質の場合のＸ値は０．５～１．８位の目標値に安定して造り込むことである。
　金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末５の平均粒子径Ｄ５０は、１０μｍ～５０μｍが好ましく、平均粒子径Ｄ５０は１５μｍ～４０μｍがより好ましい。平均粒子径Ｄ５０が１０μｍ未満では、プラズマガン２への粉末供給装置１４の供給量のバラツキが大きく、安定したＳｉＯＸの製造が行えないからである。また、平均粒子径Ｄ５０が５０μｍを超えると、６０μｍ以上の粗大粒子の混入が多く、これらの粗大粒子は、プラズマ炎３内及び高周波誘導加熱炉１９の黒鉛管（反応炉）１５内で十分気化及び反応しきれず、未反応粗大粒子として製品に混入する割合が増えるからである。 The important thing is that it does not contain metallic Si, the X value in the case of gas barrier material is 1.5 to 1.8, and the X value in the case of the negative electrode active material of lithium ion secondary battery is about 0.5 to 1.8. It is to build stably to the target value.
The average particle diameter D 50 of the mixed granulated powder 5 of metal Si powder and SiO 2 powder is preferably 10 μm to 50 μm, and the average particle diameter D 50 is more preferably 15 μm to 40 μm. This is because when the average particle diameter D 50 is less than 10 μm, the supply amount of the powder supply device 14 to the plasma gun 2 varies greatly, and stable production of SiO X cannot be performed. When the average particle diameter D 50 exceeds 50 μm, coarse particles of 60 μm or more are often mixed, and these coarse particles are sufficiently contained in the plasma flame 3 and the graphite tube (reaction furnace) 15 of the high-frequency induction heating furnace 19. This is because vaporization and reaction cannot be completed, and the proportion of unreacted coarse particles mixed in the product increases.
　本実施形態において、金属Ｓｉ粉末とＳｉＯ２粉末との造粒方法は、噴霧乾燥法、転動造粒法、流動造粒法、撹拌造粒法等特に限定するものではないが、一般的な噴霧乾燥法（スプレードライ）が好ましい。
　噴霧乾燥法（スプレードライ）では、数μｍまでの微粒子（一次粒子）と液状有機物バインダー剤とを混合タンク内に混入し、スラリー化した後、ポンプでチャンバー内に送り圧縮空気で噴霧する。これを上方から乾燥気流で凝集粒子（二次粒子）として乾燥させ、下方のコレクターで回収する。
　有機物バインダー剤には、ポリビニルアルコール（ＰＶＡ）、カルボキシルメチルセルロース（ＣＭＣ）、コンスターチ、パラフィン、レジン等が用いられる。 In this embodiment, the granulation method of the metal Si powder and the SiO 2 powder is not particularly limited, such as a spray drying method, a tumbling granulation method, a fluidized granulation method, a stirring granulation method, etc. A spray drying method (spray drying) is preferred.
In the spray drying method (spray drying), fine particles (primary particles) of up to several μm and a liquid organic binder are mixed in a mixing tank, slurried, then fed into a chamber by a pump and sprayed with compressed air. This is dried as agglomerated particles (secondary particles) from above by a dry air stream and collected by the lower collector.
For the organic binder, polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), starch, paraffin, resin or the like is used.
　次に、工程（Ａ）で用いる装置について説明する。
　工程（Ａ）では、プラズマ加熱装置に、ＤＣ（直流）プラズマ装置１を使用した。
　プラズマガン先端部２ａは、例えば、図２に示すように、陰極７を作動ガス通路８内に配置し、作動ガス（Ｎ２等）９を陰極７に沿って作動ガス通路８から噴出する電極ホルダー６と、この電極ホルダー６に連通する陽極で構成されるノズル１０とを有する。このノズル１０の外周には、冷却水１２で冷却するウオータージャケット１１を設ける。電極ホルダー６から噴出する作動ガス（Ｎ２等）９を陰極７と陽極との放電によってプラズマ炎３としてプラズマガン先端部２ａから噴出するように構成されている。
　また、プラズマガン先端部２ａは、プラズマ炎３の噴出速度を遅くするため、ノズル１０の径を大きくして、プラズマ炎３の速度を１５０ｍ／ｓｅｃ以下にし、反応時間を長くして金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末５の溶融及び気化を促進させる特殊な構造としてある。 Next, the apparatus used at a process (A) is demonstrated.
In step (A), a DC (direct current) plasma apparatus 1 was used as the plasma heating apparatus.
For example, as shown in FIG. 2, the plasma gun tip 2 a is an electrode in which the cathode 7 is disposed in the working gas passage 8 and the working gas (N 2 or the like) 9 is ejected from the working gas passage 8 along the cathode 7. A holder 6 and a nozzle 10 composed of an anode communicating with the electrode holder 6 are provided. A water jacket 11 that is cooled by cooling water 12 is provided on the outer periphery of the nozzle 10. A working gas (N 2 or the like) 9 ejected from the electrode holder 6 is ejected from the plasma gun tip 2a as a plasma flame 3 by discharge between the cathode 7 and the anode.
Further, the plasma gun tip 2a increases the diameter of the nozzle 10 in order to slow down the ejection speed of the plasma flame 3, so that the speed of the plasma flame 3 is 150 m / sec or less, and the reaction time is increased to increase the metal Si powder. This is a special structure that promotes the melting and vaporization of the mixed granulated powder 5 of SiO 2 and SiO 2 powder.
　プラズマガン先端部２ａの近傍には、プラズマガン２から噴出されるプラズマ炎３に向かって金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末５をキャリアガス（Ｎ２等）にて供給する内部供給方式の粉末供給ノズル４が配置されている。
　この粉末供給ノズル４には、内部供給方式と図示しない外部供給方式とがある。プラズマ炎３の高温部に材料を効率よく供給し、材料の溶融効率を上げる面からは内部供給方式が好ましい。しかし、内部供給方式はノズル１０を構成する陽極が損傷を受けやすい。また、溶融した材料が陽極で構成されるノズル１０内に付着し、ノズル１０の穴が閉塞しやすいという欠点がある。それぞれ一長一短があるが、何れの方式を用いることも可能である。粉末の供給箇所は、材料供給量にもよるが、ノズル１０の円周方向に１～４ヵ所からプラズマ炎３の中心に向かって供給することが望ましい。
　粉末供給ノズル４には、粉末造粒装置１３で造粒した金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末５を供給する粉末供給装置１４が配管を介して接続されている。 In the vicinity of the plasma gun tip 2a, there is an interior in which a mixed granulated powder 5 of metal Si powder and SiO 2 powder is supplied by a carrier gas (N 2 or the like) toward a plasma flame 3 ejected from the plasma gun 2 A powder supply nozzle 4 of a supply system is arranged.
The powder supply nozzle 4 has an internal supply system and an external supply system (not shown). From the viewpoint of efficiently supplying the material to the high temperature part of the plasma flame 3 and increasing the melting efficiency of the material, the internal supply method is preferable. However, in the internal supply method, the anode constituting the nozzle 10 is easily damaged. Moreover, there exists a fault that the fuse | melted material adheres in the nozzle 10 comprised with an anode, and the hole of the nozzle 10 is easy to block | close. Each method has its advantages and disadvantages, but any method can be used. Depending on the amount of material supply, the powder supply location is preferably from 1 to 4 locations in the circumferential direction of the nozzle 10 toward the center of the plasma flame 3.
A powder supply device 14 for supplying a mixed granulated powder 5 of a metal Si powder and a SiO 2 powder granulated by the powder granulator 13 is connected to the powder supply nozzle 4 via a pipe.
　本実施形態では、工程（Ａ）を実現するためのプラズマ装置に、ＤＣ（直流）プラズマ装置１を使用したが、本発明は、ＤＣ（直流）プラズマ装置１に限らず、ＲＦ（高周波誘導）熱プラズマ装置等を用いても良い。しかし、熱エネルギー変換効率が高く、且つ、金属Ｓｉ粉末を完全気化させ、ＳｉＯＸ化反応を効率よく大量処理するためには、ＤＣ（直流）プラズマ装置１が好ましい。
　特に、ＤＣ（直流）プラズマ装置１は、プラズマ炎３で金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末５を６，０００Ｋ（５，７２７℃）以上の高温度で溶融させることができるので、ＳｉＯＸを高周波誘導加熱炉１９にて２，０００Ｋ（１，７２７℃）以上の高温で完全気化反応させる工程（Ｂ）との組み合わせを可能とすることができる。 In the present embodiment, the DC (direct current) plasma device 1 is used as the plasma device for realizing the step (A). However, the present invention is not limited to the DC (direct current) plasma device 1, but RF (high frequency induction). A thermal plasma apparatus or the like may be used. However, the DC (direct current) plasma apparatus 1 is preferable in order to have high thermal energy conversion efficiency, to completely vaporize the metal Si powder, and to efficiently process the SiO X conversion reaction in a large amount.
In particular, the DC (direct current) plasma apparatus 1 can melt the mixed granulated powder 5 of metal Si powder and SiO 2 powder at a high temperature of 6,000 K (5,727 ° C.) or more with the plasma flame 3. , SiO X can be combined with the step (B) of completely vaporizing the high temperature induction furnace 19 at a high temperature of 2,000 K (1,727 ° C.) or higher.
　また、通常のＤＣ（直流）プラズマ装置は、プラズマジェットのプラズマ炎３であるフレームの速度がマッハ２レベルの高流速で得られるのが特徴である。しかし、本実施形態では、金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末５を溶融（一部は気化する）させるため、プラズガン先端部２ａ出口のフレームの速度を極力遅くする。そのため、原料粉末の飛翔速度を遅くするようにプラズマガン先端部２ａのノズル１０の径を大きくして、ＳｉＯＸ液滴の飛翔速度を１５０ｍ／ｓｅｃ～３ｍ／ｓｅｃにして後段の高周波誘導加熱炉１９に吹き込む構造にする。
　プラズマガン先端部２ａのノズル１０の径は、ＳｉＯＸ液滴の飛翔速度を調整するために、ノズル１０の先端に向かって段階的又は曲線的に拡大するように構成にするとともに、陽極と陰極７との距離を適正に維持した構造に組み合わせた一対の部品として取り換えできる構造とする。 In addition, a normal DC (direct current) plasma apparatus is characterized in that the velocity of the flame, which is the plasma flame 3 of the plasma jet, is obtained at a high flow rate of Mach 2 level. However, in this embodiment, since the mixed granulated powder 5 of the metal Si powder and the SiO 2 powder is melted (partially vaporized), the speed of the frame at the outlet of the plasm gun tip 2a is made as low as possible. Therefore, the diameter of the nozzle 10 of the plasma gun tip 2a is increased so as to slow down the flying speed of the raw material powder, and the flying speed of the SiO X droplet is set to 150 m / sec to 3 m / sec. 19 is blown into the structure.
The diameter of the nozzle 10 of the plasma gun tip 2a is configured to expand stepwise or in a curve toward the tip of the nozzle 10 in order to adjust the flying speed of the SiO X droplet, and the anode and cathode 7 is a structure that can be exchanged as a pair of parts combined with a structure that maintains the distance to 7 appropriately.
　ＳｉＯＸ液滴の飛翔速度が１５０ｍ／ｓｅｃを超えると、高周波誘導加熱炉１９内での反応時間が短く、高周波誘導加熱炉１９内で完全に気化させて反応を起こさせることが難しい。ＳｉＯＸ液滴の飛翔速度が３ｍ／ｓｅｃ未満では、気化しきれない粗大液滴が高周波誘導加熱炉１９内の最適反応温度部まで飛翔せず、高周波誘導加熱炉１９の底部に堆積する虞がある。
　一方、ＲＦ（高周波誘導）熱プラズマ装置は、１０，０００Ｋ（９，７２７℃）以上の高温度プラズマ炎は得られるが、プラズマへの熱エネルギー変換効率が低く、また原料供給量が１０ｇ／ｍｉｎ位と非常に少ないために生産性が悪く、生産コストが高くなり、量産装置としては好ましくない。 When the flying speed of the SiO X droplet exceeds 150 m / sec, the reaction time in the high-frequency induction heating furnace 19 is short, and it is difficult to cause the reaction to be completely vaporized in the high-frequency induction heating furnace 19. When the flying speed of the SiO X droplet is less than 3 m / sec, a coarse droplet that cannot be vaporized does not fly to the optimum reaction temperature portion in the high-frequency induction heating furnace 19 and may accumulate on the bottom of the high-frequency induction heating furnace 19. is there.
On the other hand, an RF (high frequency induction) thermal plasma apparatus can produce a high-temperature plasma flame of 10,000 K (9,727 ° C.) or higher, but has a low thermal energy conversion efficiency to plasma, and a feed rate of 10 g / min. Therefore, the productivity is poor and the production cost is high, which is not preferable as a mass production apparatus.
　次に、工程（Ｂ）について説明する。
　図１に示すように、ＤＣ（直流）プラズマ装置１の先端には、工程（Ｂ）を実現するために、高周波誘導加熱炉１９が接続されている。
　高周波誘導加熱炉１９は、水冷石英管１７の内部に断熱材１６で周囲を覆われた耐熱温度３，０００℃の黒鉛管（反応管）１５を挿入し、水冷石英管１７の外周に高周波誘導コイル１８を配置した構造である。
　黒鉛管（反応管）１５の内部温度は、１，６００℃～２，７００℃に任意に温度コントロールできる構造としてある。 Next, the step (B) will be described.
As shown in FIG. 1, a high frequency induction heating furnace 19 is connected to the tip of the DC (direct current) plasma apparatus 1 in order to realize the step (B).
In the high frequency induction heating furnace 19, a graphite tube (reaction tube) 15 having a heat-resistant temperature of 3,000 ° C., which is covered with a heat insulating material 16, is inserted into the water-cooled quartz tube 17, and the high-frequency induction furnace is disposed around the water-cooled quartz tube 17. In this structure, the coil 18 is arranged.
The internal temperature of the graphite tube (reaction tube) 15 can be arbitrarily controlled from 1,600 ° C. to 2,700 ° C.
　図１に示すように、黒鉛管（反応管）１５の上部に設けた開口部１５ａには、工程（Ｃ）を実現するために、Ｎ２、Ａｒ等の圧縮不活性ガスによる冷却を行う冷却装置２０が配置されている。
　工程（Ｂ）を実現するための高周波誘導加熱炉１９は、黒鉛管（反応管）１５内の温度を２，０００Ｋ（１，７２７℃）以上として、ＳｉＯＸ化反応を十分行わせるために、耐熱温度の高い黒鉛管を使用するのが好ましい。
  なお、金属Ｓｉ粉末をＤＣ（直流）プラズマジェト中に吹き込み、作動ガスとして酸素ガスＯ２を使用し、ＳｉＯＸを製造する方法も考えられる。しかし、この方法では、ＤＣ（直流）プラズマジェット内で金属Ｓｉ粉末と酸素ガスとの均一な反応が起こらない。そのため、本実施形態のようにプラズマガン２の後に高周波誘導加熱炉１９を設けて、十分に気化させて均一な反応を起こさせることも考えられる。
　しかし、この場合、金属Ｓｉとの未反応酸素ガスＯ２が２，０００Ｋ（１，７２７℃）以上の高温度の黒鉛管（反応管）１５と反応してＣＯとなるため、ＳｉＯＸとしての組成が安定しない。従って、プラズマ炎３による金属Ｓｉ粉末と酸素ガスＯ２との気相反応を黒鉛管（反応管）１５を用いた高周波誘導加熱炉１９内で行わせることは難しい。
　なお、本実施形態では、加熱炉に高周波誘導加熱炉１９を用いた場合について説明したが、本発明はこれに限らず、黒鉛ヒーターにより黒鉛管（反応管）を加熱する黒鉛ヒーター加熱炉を用いても良い。 As shown in FIG. 1, the opening 15a provided in the upper part of the graphite tube (reaction tube) 15 is cooled by cooling with a compressed inert gas such as N 2 or Ar in order to realize the step (C). A device 20 is arranged.
The high-frequency induction heating furnace 19 for realizing the step (B) has a temperature in the graphite tube (reaction tube) 15 of 2,000 K (1,727 ° C.) or higher so that the SiO X conversion reaction is sufficiently performed. It is preferable to use a graphite tube having a high heat resistance temperature.
A method of producing SiO X by blowing metal Si powder into a DC (direct current) plasma jet and using oxygen gas O 2 as a working gas is also conceivable. However, in this method, a uniform reaction between the metal Si powder and oxygen gas does not occur in a DC (direct current) plasma jet. Therefore, it is also conceivable to provide a high-frequency induction heating furnace 19 after the plasma gun 2 as in the present embodiment to cause sufficient vaporization to cause a uniform reaction.
However, in this case, since the unreacted oxygen gas O 2 with a metal Si is CO reacts with 2,000K (1,727 ℃) or high temperature graphite tube (reaction tube) 15, as SiO X The composition is not stable. Therefore, it is difficult to cause the gas phase reaction between the metal Si powder and the oxygen gas O 2 by the plasma flame 3 in the high frequency induction heating furnace 19 using the graphite tube (reaction tube) 15.
In addition, although this embodiment demonstrated the case where the high frequency induction heating furnace 19 was used for the heating furnace, this invention is not restricted to this, The graphite heater heating furnace which heats a graphite tube (reaction tube) with a graphite heater is used. May be.
　次に、工程（Ｃ）について説明する。
　図１、図３に示すように、Ｎ２、Ａｒ等の圧縮不活性ガスによる冷却を行う冷却装置２０は、黒鉛管（反応管）１５の上部に設けた開口部１５ａに連結され、常温のＮ２、Ａｒ等の圧縮不活性ガスをリング状に斜め方向に噴出させるリング状ノズル２２と、リング状ノズル２２に連結されＮ２、Ａｒ等の圧縮不活性ガスで高温度ＳｉＯＸガスを８００℃に急冷却する断熱二重管２３とで構成されている。
　リング状ノズル２２には、常温のＮ２、Ａｒ等の圧縮不活性ガスを供給する装置（図示せず）に連絡する管路２２ａが接続されている。
　また、断熱二重管２３には、冷却水又はＮ２、Ａｒ等の圧縮不活性ガスを取り込む入口２３ａと、出口２３ｂとが設けられている。
　高周波誘導加熱炉１９の黒鉛管（反応管）１５で生成された２，０００Ｋ（１，７２７℃）以上の高温度ＳｉＯＸガスは、高周波誘導加熱炉１９の黒鉛管（反応管）１５の上部に設けた開口部１５ａに連結する冷却装置２０内に導入される。Ｎ２、Ａｒ等の圧縮不活性ガスをリング状に噴出するリング状ノズル２２から斜め方向に噴出させ、高温度ＳｉＯＸガスをエジェクター効果で吸引するとともに、瞬時に８００℃以下に急冷却させ、アモルファス状のＳｉＯＸ微粉末２５ａを析出させる。このＳｉＯＸガスは、８００℃以下では殆ど安定な固体となる。 Next, process (C) is demonstrated.
As shown in FIGS. 1 and 3, a cooling device 20 that performs cooling with a compressed inert gas such as N 2 or Ar is connected to an opening 15 a provided at an upper portion of a graphite tube (reaction tube) 15, and has a normal temperature. A ring-shaped nozzle 22 for injecting a compressed inert gas such as N 2 and Ar in a ring shape obliquely, and a high-temperature SiO X gas 800 connected to the ring-shaped nozzle 22 with a compressed inert gas such as N 2 and Ar. It is comprised with the heat insulation double tube 23 which cools rapidly to degreeC.
The ring-shaped nozzle 22 is connected to a pipe line 22a that communicates with a device (not shown) that supplies a compressed inert gas such as N 2 or Ar at room temperature.
The heat insulation double pipe 23 is provided with an inlet 23a for taking in cooling water or a compressed inert gas such as N 2 and Ar, and an outlet 23b.
The high temperature SiO X gas of 2,000 K (1,727 ° C.) or more generated in the graphite tube (reaction tube) 15 of the high frequency induction heating furnace 19 is the upper part of the graphite tube (reaction tube) 15 of the high frequency induction heating furnace 19. It is introduced into the cooling device 20 that is connected to the opening 15a. A compressed inert gas such as N 2 or Ar is jetted in an oblique direction from a ring-like nozzle 22 that jets in a ring shape, and high-temperature SiO X gas is sucked by the ejector effect and instantly cooled to 800 ° C. or less, Amorphous SiO X fine powder 25a is deposited. This SiO X gas becomes an almost stable solid at 800 ° C. or lower.
　よって、ＳｉＯＸ析出物は、金属Ｓｉ粉末とＳｉＯ２粉末とに不均化する間もなく、サブミクロン（１μｍ以下）のアモルファス状のＳｉＯＸ微粉末２５ａとして析出する。
　このＳｉＯＸ微粉末２５ａの粒子径はサブミクロン（１μｍ以下）で非常に細かいため、通常のサイクロンでは捕集しにくい。故に、一次冷却用のＮ２、Ａｒ等の圧縮不活性ガスの吹き込みで、断熱二重管２３内のガス流速を高速にして、水冷却サイクロン２４内に円周方向に８００℃以下に一次冷却された高温度ガスを導入する。
　このとき、水冷却サイクロン２４への誘導パイプとなる断熱二重管２３は、高温度（約８００℃）のガスが通るため、断熱二重管２３は冷却水又は一次冷却用のＮ２、Ａｒ等の圧縮不活性ガスを通して冷却し、また不活性ガスをリング状ノズル２２から吹き込む構造とする。 Therefore, the SiO X precipitate is deposited as submicron (1 μm or less) amorphous SiO X fine powder 25a without being disproportionated into the metal Si powder and the SiO 2 powder.
Since the particle diameter of the SiO X fine powder 25a is very fine with a submicron (1 μm or less), it is difficult to collect with a normal cyclone. Therefore, by blowing compressed inert gas such as N 2 or Ar for primary cooling, the gas flow rate in the heat insulating double pipe 23 is increased, and the water is cooled primarily to 800 ° C. or less in the circumferential direction in the water cooling cyclone 24. Introduced high temperature gas.
At this time, since the high temperature (about 800 ° C.) gas passes through the heat insulating double pipe 23 serving as a guide pipe to the water cooling cyclone 24, the heat insulating double pipe 23 is N 2 , Ar for cooling water or primary cooling. In this structure, cooling is performed through a compressed inert gas such as the like, and the inert gas is blown from the ring-shaped nozzle 22.
　断熱二重管２３は水あるいは冷却ガスで冷却されるが、冷却しすぎると、ＳｉＯＸガスがＳｉＯＸ固体として析出し、断熱二重管２３内に堆積し、断熱二重管２３内が詰まってしまう。この断熱二重管２３内に析出堆積したＳｉＯＸの固体（粉末状、又はフレーク状）を回収するために、短時間周期で操業はバッチ操業とならざるを得ない。そのため、断熱二重管２３を水で間接冷却する場合は、流量等を調節して断熱二重管２３内でＳｉＯＸガスが析出しない温度に維持することが必要である。あるいは、吹き込み用のＮ２、Ａｒ等の圧縮不活性ガスで断熱二重管２３を冷却すれば、断熱二重管２３内温度は高温度に維持できる。また、管内ガス流速が非常に速いので、堆積物詰まり等の問題が発生しない。 The heat insulation double tube 23 is cooled with water or a cooling gas. However, if it is cooled too much, SiO X gas is deposited as a SiO X solid and deposited in the heat insulation double tube 23, and the heat insulation double tube 23 is clogged. End up. In order to collect the SiO X solid (powder or flakes) deposited and deposited in the heat insulating double tube 23, the operation must be a batch operation in a short cycle. Therefore, when the heat insulation double pipe 23 is indirectly cooled with water, it is necessary to adjust the flow rate and the like so as to maintain a temperature at which the SiO X gas does not precipitate in the heat insulation double pipe 23. Alternatively, if cooling the N 2, Ar insulated double pipe 23 with compressed inert gas such as for blowing, the insulated double pipe 23 temperature can be maintained at a high temperature. Moreover, since the gas flow rate in the pipe is very fast, problems such as deposit clogging do not occur.
　次に、工程（Ｄ）について説明する。
　図１、図３に示すように、Ｎ２、Ａｒ等の圧縮不活性ガスによる冷却を行う冷却装置２０の断熱二重管２３は、水冷却サイクロン２４に連絡する。
　ここで冷却されたＳｉＯＸ微粉末２５ａは、粒子径が成長或いは凝集してサイクロン側壁及び下部に付着堆積する。
　水冷却サイクロン２４の下部には、水冷却サイクロン２４で冷却されて粒子径が成長或いは凝集してサイクロン側壁及び下部に付着堆積したＳｉＯＸ粉末２５ｂを回収するホッパー２６が配置されている。 Next, process (D) is demonstrated.
As shown in FIGS. 1 and 3, the heat insulating double tube 23 of the cooling device 20 that performs cooling with a compressed inert gas such as N 2 or Ar communicates with the water cooling cyclone 24.
The SiO X fine powder 25a cooled here grows or aggregates as the particle size grows and agglomerates and deposits on the side walls and the lower part of the cyclone.
Below the water-cooled cyclone 24 is disposed a hopper 26 that recovers the SiO X powder 25b that has been cooled by the water-cooled cyclone 24 and whose particle diameter has grown or aggregated and deposited and deposited on the side wall and the lower part of the cyclone.
　高温度のＳｉＯＸガスは、低温度の水冷却サイクロン２４の側壁に沿って流れるため非常に冷却効率が良く、微粉のＳｉＯＸ粉末２５ｂは更に急冷却されることにより、粒子径が二次粒子として大きく成長或いは凝集し、平均粒子径Ｄ５０が１０μｍ～２０μｍの粉末となる。
　粒子径が大きくなることにより、ＳｉＯＸ粉末２５ｂは水冷却サイクロン２４内で大半回収されるようになる。
　水冷却サイクロン２４内に溜まったＳｉＯＸ粉末２５ｂは、下部のホッパー２６内に一定以上溜まったら、定期的に回収することにより、ＳｉＯＸ粉末としてほぼ連続的に製造することができる。 Since the high temperature SiO X gas flows along the side wall of the low temperature water cooling cyclone 24, the cooling efficiency is very good, and the fine powder SiO X powder 25b is further rapidly cooled, so that the particle size becomes a secondary particle. greatly grow or aggregate as an average particle diameter D 50 is the powder of 10 [mu] m ~ 20 [mu] m.
By increasing the particle diameter, most of the SiO X powder 25b is recovered in the water-cooled cyclone 24.
The SiO X powder 25b accumulated in the water-cooled cyclone 24 can be produced almost continuously as SiO X powder by periodically collecting the SiO X powder 25b when it accumulates in the lower hopper 26 over a certain level.
　高温化したＳｉＯＸガスは、ゆっくり徐冷されると１，７００℃以下くらいから次第にＳｉＯＸガス中に結晶核が析出して壁面等に固着し、成長してバルク状の析出物となる。特にＳｉＯの析出物は焼結体状のバルクとなるため、これを紛体とするためには取り出したバルク状のものを後で別途破砕する必要がある。
　このため、そのバルク状の塊の取り出しはバッチ式となり作業性が悪くなるばかりでなく、それを微粉末にするのに粉砕工程を通す必要があるためコストが高くなり、また不純物も混入し易い。
　一方、ＳｉＯＸガスをＮ２、Ａｒ等の圧縮不活性ガスで急冷すると、冷却速度により析出成長核の大きさは異なってくるが、一般に０．０１μｍから数μｍの微粉となり、アモルファス状の非結晶構造とすることができる。
　ＳｉＯは、通常準安定な結晶構造をもち、金属ＳｉとＳｉＯ２とのアモルファス状の集合構造をもつが、８００℃以上の高温域で加熱されると不均化反応によって、次第に金属Ｓｉ領域とＳｉＯ２領域とに分離する。 When the SiO X gas at a high temperature is slowly cooled slowly, crystal nuclei gradually precipitate in the SiO X gas from about 1700 ° C. or lower, adhere to the wall surface, etc., and grow into bulk precipitates. In particular, since the SiO precipitate is in the form of a sintered bulk, it is necessary to separately pulverize the removed bulk in order to make this a powder.
For this reason, the removal of the bulk lump becomes a batch type and not only the workability is deteriorated, but also it is necessary to go through a pulverization process to make it a fine powder, and the cost is high, and impurities are easily mixed. .
On the other hand, when the SiO X gas is rapidly cooled with a compressed inert gas such as N 2 or Ar, the size of the precipitation growth nuclei varies depending on the cooling rate, but generally becomes a fine powder of 0.01 μm to several μm, and the amorphous non-crystalline It can be a crystal structure.
SiO usually has a metastable crystal structure and has an amorphous aggregate structure of metal Si and SiO 2 , but when heated in a high temperature region of 800 ° C. or higher, it gradually becomes dissociated by the disproportionation reaction. Separated into SiO 2 region.
　故に、ＳｉＯＸガスをＮ２、Ａｒ等の圧縮不活性ガスで８００℃以下に希釈急冷し、アモルファス状のＳｉＯＸ微粉末として析出させて回収することが非常に重要である。その場合の粒子径は、Ｎ２、Ａｒ等の圧縮不活性ガスの吹き込み量を調整することで０．０１μｍ～１０μｍに調整することが好ましい。
　ＳｉＯＸ微粉末の粒子径が０．０１μｍ未満のナノ粒子は、リチウムイオン二次電池の負極活物質として使用する場合には、粒子表面積が大きくバインダーとの混練が難しく電極への塗工性で問題が起こり易い。また、ＳｉＯＸ微粉末の粒子径が１０μｍを超える粒子は、リチウムイオンの吸放出による体積膨張収縮によって電極物質の割れ、或いは電極からの剥がれが生じ易く、リチウムイオン二次電池の負極活物質としては好ましくない。 Therefore, it is very important to dilute and quench the SiO X gas with a compressed inert gas such as N 2 or Ar to 800 ° C. or less, and deposit and recover it as amorphous SiO X fine powder. In this case, the particle diameter is preferably adjusted to 0.01 μm to 10 μm by adjusting the amount of compressed inert gas such as N 2 or Ar.
Nanoparticles with a particle size of SiO X fine powder of less than 0.01 μm have a large particle surface area and are difficult to knead with a binder when used as a negative electrode active material for a lithium ion secondary battery. Problems are likely to occur. In addition, particles having a particle size of SiO X fine powder exceeding 10 μm are liable to crack or peel off from the electrode due to volume expansion / contraction due to absorption / release of lithium ions, and as a negative electrode active material for lithium ion secondary batteries. Is not preferred.
　次に、工程（Ｅ）について説明する。
　水冷却サイクロン２４は、ここで析出しなかったＳｉＯＸ微粉末を真空ポンプ２８によって吸引して捕集するバグフィルタ２７に管路２４ａを介して連絡している。
　水冷却サイクロン２４内で捕集できなかつたサブミクロン（１μｍ以下）以下のＳｉＯＸ微粉末は、工程（Ｅ）のバグフィルタ２７で除塵し、クリーンな排気ガスを大気に放出する。勿論、ここで回収されたダストもＳｉＯＸ粉末製品として回収されるため、製品歩留まりも高くなる。 Next, process (E) is demonstrated.
The water-cooled cyclone 24 communicates with a bag filter 27 that sucks and collects the SiO X fine powder not deposited here by a vacuum pump 28 via a pipe line 24a.
The submicron (1 μm or less) SiO X fine powder that could not be collected in the water-cooled cyclone 24 is removed by the bag filter 27 in step (E), and clean exhaust gas is released to the atmosphere. Of course, since the dust collected here is also collected as a SiO X powder product, the product yield is also increased.
　なお、本実施形態において、高周波誘導加熱炉１９内は、３０ｋＰａ～８０ｋＰａの減圧下で操業することにより、金属Ｓｉ粉末とＳｉＯ２粉末との反応温度を下げ、ＳｉＯＸ化反応をより促進させることができる。
　この場合、バグフィルタ２７の後ろで、真空ポンプ２８により吸引することにより、高周波誘導加熱炉１９からバグフィルタ２７までの全工程を減圧操業する。
　減圧操業することによりＳｉＯＸの気化温度も下がるので、高周波誘導加熱炉１９内の温度を低く抑えることができ、高周波誘導コイル１８の加熱容量も小さくすることができる。
　ただし、減圧操業の場合、バグフィルタ２７の入口温度をバグフィルタ２７の濾布耐熱温度以下に冷却するために、水冷却サイクロン２４の伝熱面積を大きくし、水冷却サイクロン２４内で十分冷却する必要がある。この場合は、バグフィルタ２７後のクリーンな排気ガスを冷却装置２０の冷媒として循環することは難しい。
　この減圧操業は十分条件であり必ずしも絶対必要条件ではなく、減圧設備は投資とその効果で適宜判断することができる。 In this embodiment, the inside of the high-frequency induction heating furnace 19 is operated under a reduced pressure of 30 kPa to 80 kPa, thereby lowering the reaction temperature between the metal Si powder and the SiO 2 powder and further promoting the SiO X conversion reaction. Can do.
In this case, all the processes from the high-frequency induction heating furnace 19 to the bag filter 27 are operated under reduced pressure by suctioning with the vacuum pump 28 behind the bag filter 27.
By operating under reduced pressure, the vaporization temperature of SiO X is lowered, so that the temperature in the high-frequency induction heating furnace 19 can be kept low, and the heating capacity of the high-frequency induction coil 18 can also be reduced.
However, in the case of a decompression operation, in order to cool the inlet temperature of the bag filter 27 below the heat resistance temperature of the filter cloth of the bag filter 27, the heat transfer area of the water cooling cyclone 24 is increased and the water cooling cyclone 24 is sufficiently cooled. There is a need. In this case, it is difficult to circulate clean exhaust gas after the bag filter 27 as a refrigerant of the cooling device 20.
This decompression operation is a sufficient condition and not necessarily an absolute requirement, and the decompression facility can be appropriately determined based on the investment and its effect.
　（第二実施形態）
　本発明の第二実施形態を図４に基づいて説明する。
　本実施形態は、工程（Ｅ）においてバグフィルタ２７を通過したクリーンな排気ガスを、真空ポンプ２８によって大気に放出する第一実施形態の方式に代えて、バグフィルタ２７を通過後のクリーンな排気ガスを、不活性ガスとして循環使用するための不活性ガス循環装置を冷却装置２０との間に設けた点で、第一実施形態とは相違する。
　従って、本実施形態では、第一実施形態における工程（Ａ）、工程（Ｂ）及び工程（Ｄ）の説明は省略する。
　先ず、工程（Ｃ）について説明する。
冷却装置２０は、図５に示すように、リング状ノズル２２に接続する管路２２ａに三方弁２２ｂを介して初期投入圧縮不活性ガスを導入する管路２２ｃと、循環圧縮不活性ガスを導入する管路２２ｄとを接続している。 (Second embodiment)
A second embodiment of the present invention will be described with reference to FIG.
In this embodiment, instead of the method of the first embodiment in which the clean exhaust gas that has passed through the bag filter 27 in the step (E) is discharged to the atmosphere by the vacuum pump 28, the clean exhaust gas that has passed through the bag filter 27 is used. The second embodiment is different from the first embodiment in that an inert gas circulation device for circulating gas as an inert gas is provided between the cooling device 20 and the gas.
Therefore, in this embodiment, description of the process (A) in the first embodiment, the process (B), and the process (D) is omitted.
First, the step (C) will be described.
As shown in FIG. 5, the cooling device 20 introduces an initially charged compressed inert gas into a pipeline 22 a connected to the ring-shaped nozzle 22 via a three-way valve 22 b and a circulating compressed inert gas. The pipe line 22d to be connected is connected.
　次に、工程（Ｅ）について説明する。
　不活性ガス循環装置は、バグフィルタ２７と、不活性ガス冷却装置３４とで構成されている。バグフィルタ２７には、バグフィルタ２７を通過したクリーンな排気ガスを導く管路２９が設けられている。
バグフィルタ２７は、水冷却サイクロン２４に管路２４ａを介して連絡している。
不活性ガス冷却装置３４は、管路２９の下流側に設けられ、排気ガスを常温まで冷却する熱交換器３０と、この熱交換器３０の下流側に設けられる管路３１と、この管路３１の下流側に設けられ、排気ガスを昇圧する高圧ブロワー３２と、この高圧ブロワー３２の下流側と冷却装置２０の管路２２ｄとを接続する管路３３とで構成されている。管路３３には、プラズマガン２で吹込まれた作動ガス（Ｎ２、Ａｒガス等）相当の余剰ガスを大気放出する排気管３５が三方弁３６を介して設けられている。 Next, process (E) is demonstrated.
The inert gas circulation device includes a bag filter 27 and an inert gas cooling device 34. The bag filter 27 is provided with a conduit 29 that guides clean exhaust gas that has passed through the bag filter 27.
The bag filter 27 communicates with the water cooling cyclone 24 via a pipe line 24a.
The inert gas cooling device 34 is provided on the downstream side of the pipe line 29, the heat exchanger 30 for cooling the exhaust gas to room temperature, the pipe line 31 provided on the downstream side of the heat exchanger 30, and the pipe line The high pressure blower 32 is provided downstream of the high pressure blower 31 and boosts the exhaust gas. The high pressure blower 32 is connected to the downstream side of the high pressure blower 32 and the pipe 22 d of the cooling device 20. The pipe 33 is provided with an exhaust pipe 35 through a three-way valve 36 that discharges surplus gas equivalent to the working gas (N 2 , Ar gas, etc.) blown by the plasma gun 2 to the atmosphere.
本実施形態によれば、バグフィルタ２７でＳｉＯＸ微粒子を回収集塵後のクリーンな排気ガスを熱交換器３０で常温に冷却後に高圧ブロワー３２にて昇圧し、冷却装置２０に循環使用することにより、大幅なコスト低減が可能である。
また、本実施形態によれば第一実施形態と同様の作用効果を奏することができる。 According to this embodiment, clean exhaust gas after collecting and collecting SiO X fine particles by the bag filter 27 is cooled to room temperature by the heat exchanger 30 and then pressurized by the high-pressure blower 32 and circulated for use in the cooling device 20. Therefore, significant cost reduction is possible.
Moreover, according to this embodiment, there can exist an effect similar to 1st embodiment.
　以下、本発明を実施例に基づいて具体的に説明するが、本発明の範囲は、これらの実施例のみに限定されることはない。 Hereinafter, the present invention will be specifically described based on examples, but the scope of the present invention is not limited to only these examples.
　（実施例１）
　金属Ｓｉ粉末の一次原料として、半導体製造用シリコンウエーハ製造工程で発生した金属Ｓｉスラッジから再生した金属Ｓｉ粉末を使用した。
　金属Ｓｉ粉末の純度は、不純物の重金属＜５０μｇ／ｇ、平均粒子径Ｄ５０：３．７μｍであった。
　また、ＳｉＯ２粉末の粒子径分布は、平均粒子径Ｄ５０：２．４μｍであった。
　金属Ｓｉ粉末とＳｉＯ２とを重量比（ｗｔ％）１：２．１４で混合（ＳｉＯＸのＸ値：１．０）した粉末と、水と、有機バインダー（ＰＶＡ）と、分散剤とを配合して、撹拌スラリー化し、噴霧乾燥法で造粒して二次原料粉末（混合造粒粉末５）を製造した。
　混合造粒粉末５の平均粒子径Ｄ５０は、１７μｍ（＜６０μｍ）であった。 Example 1
As a primary raw material of metal Si powder, metal Si powder regenerated from metal Si sludge generated in a silicon wafer production process for semiconductor production was used.
The purity of the metal Si powder was impurity heavy metal <50 μg / g, average particle diameter D 50 : 3.7 μm.
The particle size distribution of the SiO 2 powder was an average particle size D 50 : 2.4 μm.
A powder obtained by mixing metal Si powder and SiO 2 at a weight ratio (wt%) of 1: 2.14 (X value of SiO X : 1.0), water, an organic binder (PVA), and a dispersant. It mix | blended, made into stirring slurry, and granulated by the spray-drying method, and manufactured the secondary raw material powder (mixed granulated powder 5).
The average particle diameter D 50 of the mixed granulated powder 5 was 17μm (<60μm).
　本実施例では、図１に示すように、プラズマ加熱装置は、ＤＣ（直流）プラズマ装置（日本ユテク製：ＳＧ-１００溶射ガン）１を使用した。ただし、プラズマ炎３の噴出速度を遅くするためプラズマガン先端部２ａのノズル１０の径を大きくした特殊なノズルを採用した。
　ＤＣ（直流）プラズマ装置１に金属Ｓｉ粉末とＳｉＯ２粉末との混合造粒粉末５をキャリアガス（Ｎ２）にて３０ｇ／ｍｉｎの供給速度で供給した。
　作動ガス９にはＮ２（６０Ｌ／ｍｉｎ）を使用し、出力：３５Ｖ×７５０Ａで操業した。
　ＤＣ（直流）プラズマ装置１の先端に高周波誘導加熱炉１９を接続した。
　高周波誘導加熱炉１９は、水冷石英管１７内部に断熱材１６と、耐熱温度３，０００℃の黒鉛管（反応管）１５とを挿入し、高周波誘導コイル１８で加熱する構造である。
　黒鉛管（反応管）１５の内部温度は、１，６００℃～２，７００℃に任意に温度コントロールできる構造で、２，５００℃で操業した。 In this embodiment, as shown in FIG. 1, a DC (direct current) plasma apparatus (manufactured by Nippon Yutech Co., Ltd .: SG-100 spray gun) 1 was used as the plasma heating apparatus. However, a special nozzle in which the diameter of the nozzle 10 at the plasma gun tip 2a is increased in order to slow down the ejection speed of the plasma flame 3.
A mixed granulated powder 5 of metal Si powder and SiO 2 powder was supplied to a DC (direct current) plasma apparatus 1 by a carrier gas (N 2 ) at a supply rate of 30 g / min.
N 2 (60 L / min) was used as the working gas 9 and the operation was performed at an output of 35 V × 750 A.
A high frequency induction heating furnace 19 was connected to the tip of the DC (direct current) plasma apparatus 1.
The high frequency induction heating furnace 19 has a structure in which a heat insulating material 16 and a graphite tube (reaction tube) 15 having a heat resistant temperature of 3,000 ° C. are inserted into a water-cooled quartz tube 17 and heated by a high frequency induction coil 18.
The internal temperature of the graphite tube (reaction tube) 15 was such that the temperature could be arbitrarily controlled from 1,600 ° C. to 2,700 ° C., and the operation was performed at 2,500 ° C.
　プラズマ炎３で溶融液滴（一部はガス化）となったＳｉＯＸは、高温の高周波誘導加熱炉１９に吹き込まれることにより、全てＳｉＯＸガスとなり、高周波誘導加熱炉１９の上部から不活性ガス冷却装置２０の出口パイプ２１へ送られる。
　出口パイプ２１の出口部でリング状ノズル２２から常温の圧縮Ｎ２ガスをＳｉＯＸガスに４００Ｌ／ｍｉｎで吹き込み、８００℃に急冷却させた。
　８００℃に一次冷却されたＳｉＯＸはガスから微粉末となり、さらに水冷却サイクロン２４に吹き込まれる。
　水冷却サイクロン２４で冷却されたＳｉＯＸ微粉末は、粒子径が成長して水冷却サイクロン２４の側壁及び下部に付着堆積し、水冷却サイクロン２４の下部に設けたホッパー２６に集められる。
　水冷却サイクロン２４の下部に集められたＳｉＯＸ回収粉末をサンプリングし、粒子径分析及び成分分析を行った。 The SiO X that has become molten droplets (partially gasified) by the plasma flame 3 is entirely turned into SiO X gas by being blown into the high-frequency induction heating furnace 19, and is inert from the upper part of the induction induction furnace 19. It is sent to the outlet pipe 21 of the gas cooling device 20.
A compressed N 2 gas at room temperature was blown into the SiO X gas at 400 L / min from the ring-shaped nozzle 22 at the outlet of the outlet pipe 21 and rapidly cooled to 800 ° C.
The SiO X primarily cooled to 800 ° C. becomes a fine powder from the gas, and is further blown into the water-cooled cyclone 24.
The SiO X fine powder cooled by the water cooling cyclone 24 grows in particle size, adheres and accumulates on the side wall and the lower portion of the water cooling cyclone 24, and is collected in a hopper 26 provided at the lower portion of the water cooling cyclone 24.
The SiO X recovered powder collected at the bottom of the water-cooled cyclone 24 was sampled and subjected to particle size analysis and component analysis.
　（実施例２）
　金属Ｓｉ粉末：ＳｉＯ２＝１：０．７１（重量比）で混合（ＳｉＯＸのＸ値：０．５）した粉末を使用した以外は、実施例１と同じ条件で操業した。
　水冷却サイクロン２４の下部に集められたＳｉＯＸ回収粉末をサンプリングし、粒子径分析及び成分分析を行った。 (Example 2)
Operation was performed under the same conditions as in Example 1, except that powder mixed with metal Si powder: SiO 2 = 1: 0.71 (weight ratio) (X value of SiO X : 0.5) was used.
The SiO X recovered powder collected at the bottom of the water-cooled cyclone 24 was sampled and subjected to particle size analysis and component analysis.
　（実施例３）
　金属Ｓｉ粉末：ＳｉＯ２＝１：６．４３（重量比）で混合（ＳｉＯＸのＸ値：１．５）した粉末を使用した以外は、実施例１と同じ条件で操業した。
　水冷却サイクロン２４の下部に集められたＳｉＯＸ回収粉末をサンプリングし、粒子径分析及び成分分析を行った。 Example 3
Operation was performed under the same conditions as in Example 1 except that powder mixed with metal Si powder: SiO 2 = 1: 6.43 (weight ratio) (X value of SiO X : 1.5) was used.
The SiO X recovered powder collected at the bottom of the water-cooled cyclone 24 was sampled and subjected to particle size analysis and component analysis.
　実施例１～実施例３のＳｉＯＸ回収粉末サンプルについて、レーザー回折式粒度分布計（ＬＭＳ－２０００e：ＳＥＩＳＨＩＮ社製）による粒子径分析、ＦＥ－ＳＥＭ（ＳＵ８０２０：日立ハイテクノロジーズ製）による形態観察、ＥＰＭＡ（ＥＰＭＡ－１６１０：島津製作所製）によるＳｉ及びＯの定量分析及び粒子内におけるＳｉ及びＯの面分析結果、及びＸＰＳ(X-ray Photoelectron Spectrometer／JPS-9010／Ｘ線光電子分光法、日本電子株式会社製)を用いたＳｉＯＸの結合状態測定を行ったので、その結果を表１にまとめて示す。 For the SiO X recovered powder samples of Examples 1 to 3, particle size analysis with a laser diffraction particle size distribution analyzer (LMS-2000e: manufactured by SEISHIN), morphology observation with FE-SEM (SU8020: manufactured by Hitachi High Technologies), Quantitative analysis of Si and O by EPMA (EPMA-1610: manufactured by Shimadzu Corporation) and results of surface analysis of Si and O in particles, and XPS (X-ray Photoelectron Spectrometer / JPS-9010 / X-ray photoelectron spectroscopy, JEOL) As a result of measurement of the bonding state of SiO X using Co., Ltd., the results are summarized in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すごとく、実施例１～実施例３のＳｉ／ＳｉＯ２の混合比率（計算Ｘ値）に対して、ＳｉＯＸ回収粉末サンプルの分析結果は、ＥＤＳ分析、ＸＰＳ分析の何れにおいてもＸ値がほぼ原料粉末混合比率での計算Ｘ値と同等の値であった。また、ＳｉＯＸ回収粉末サンプルのＳｉＯＸの結合状態においても原料のＳｉ成分、ＳｉＯ２成分がほとんど無くなり、Ｓｕｂ－ｏｘｉｄｅ（Ｓｉ１＋、Ｓｉ２＋、Ｓｉ３＋）が生成されていることが確認された。
　また、ＳｉＯＸ回収粉末サンプルの粒子径分布も、平均粒子径Ｄ５０：１８μｍ～３３μｍ（＞５０μｍ：０％～２６％）のリチウムイオン二次電池の負極活物質の塗工に適した粒子径分布の微粉末として回収することができた。
　このように、ＳｉＯＸのＸ値を用途に応じて最適にコントロールでき、且つ、回収するＳｉＯＸは、リチウムイオン二次電池の負極活物質の塗工に適した粒子径分布の粉末であるため、粒子径調整のための粉砕工程を省略でき、ＳｉＯＸ粉末製造コスト低減のためにも非常に大きな効果があった。 As shown in Table 1, with respect to the Si / SiO 2 mixing ratio of Example 1 to Example 3 (calculated X value), the analysis result of the SiO X recovered powder sample is X in both EDS analysis and XPS analysis. The value was almost the same as the calculated X value at the raw material powder mixing ratio. It was also confirmed that the raw material Si component and SiO 2 component were almost lost even in the SiO X bonded state of the SiO X recovered powder sample, and Sub-oxide (Si 1+ , Si 2+ , Si 3+ ) was generated. .
The particle size distribution of the SiO X recovered powder sample is also suitable for application of the negative electrode active material of a lithium ion secondary battery having an average particle size D 50 : 18 μm to 33 μm (> 50 μm: 0% to 26%). It could be recovered as a fine powder of distribution.
As described above, the X value of SiO X can be optimally controlled according to the use, and the recovered SiO X is a powder having a particle size distribution suitable for application of the negative electrode active material of the lithium ion secondary battery. The pulverization step for adjusting the particle size can be omitted, and the SiO X powder production cost can be greatly reduced.
　（比較例１）
　金属Ｓｉ粉末原料を粉末のまま粉末供給量７０ｇ／ｍｉｎで、ＤＣ（直流）プラズマ装置（日本ユテク製：ＳＧ-１００溶射ガン）１のプラズマジェット中に投入し、更にプラズマ炎３内にＳｉＯのモル比相当（Ｓｉ：Ｏ＝１：１）の酸素ガスＯ２を吹き込んで、ＳｉＯＸを合成させる以外は、実施例１と同じ条件で操業した。
　その結果、平均粒子径Ｄ５０：５μｍ位の微粉末は、プラズマガン２の粉末供給装置１４では、粉末が細か過ぎて、材料が安定供給できない。しかも、Ｓｉ微粉末がプラズマ炎３の中心の高温度部（１０，０００℃）にうまく投入されにくく、多くの金属Ｓｉ粉末は溶融固化して球状化するのみで、回収された粉末は酸素との合成反応が不十分な金属Ｓｉ組成のものがほとんどであった。 (Comparative Example 1)
The raw material of the metal Si powder is put in a powder at a supply rate of 70 g / min into a plasma jet of a DC (direct current) plasma apparatus (manufactured by Nippon Yutech Co., Ltd .: SG-100 spray gun), and further SiO in the plasma flame 3 The operation was performed under the same conditions as in Example 1 except that oxygen gas O 2 corresponding to the molar ratio (Si: O = 1: 1) was blown to synthesize SiO X.
As a result, the fine powder having an average particle diameter D 50 of about 5 μm cannot be stably supplied by the powder supply device 14 of the plasma gun 2 because the powder is too fine. Moreover, it is difficult for the Si fine powder to be put into the high temperature part (10,000 ° C.) at the center of the plasma flame 3, and many metal Si powders are only melted and solidified to be spheroidized. Most of them had a metal Si composition with insufficient synthesis reaction.
　（比較例２）
　造粒粉を使用せずに金属Ｓｉ粉末：ＳｉＯ２＝１：２．１４（重量比）で混合（ＳｉＯＸのＸ値：１．０）した粉末をそのまま使用する以外は、実施例１と同じ条件で操業した。
　本比較例では、材料供給が非常に不安定で、且つ、プラズマジェットの後で、高周波誘導加熱炉１９での加熱を行ったにも関わらず、回収された粉末は、金属ＳｉとＳｉＯ２の組成のものが多く、ＳｉＯ化反応があまり起こっていなかった。
　金属Ｓｉ粉末は、造粒していないため微粉であるにも関わらず粉末がプラズマ炎３の中心部に入り難く、且つ、金属Ｓｉは気化温度が高いため完全に気化しきれず、ＳｉＯ化の気相反応が起こりにくかった。 (Comparative Example 2)
Example 1 is the same as Example 1 except that the powder mixed with metal Si powder: SiO 2 = 1: 2.14 (weight ratio) (X value of SiO X : 1.0) is used as it is without using granulated powder. Operated under the same conditions.
In this comparative example, the material supply was very unstable, and the recovered powder was composed of metal Si and SiO 2 despite being heated in the high-frequency induction heating furnace 19 after the plasma jet. There were many compositions, and SiO conversion reaction did not occur so much.
Although the metal Si powder is not granulated because it is not granulated, it is difficult for the powder to enter the center of the plasma flame 3, and the metal Si cannot be completely vaporized due to its high vaporization temperature. The gas phase reaction was difficult to occur.
　（比較例３）
　高周波誘導加熱炉１９での加熱を行わないこと以外は、実施例１と同じ条件で操業した。
　造粒しているため原料粒子径が大きい分、プラズマ炎３内で材料は溶融している。しかし、プラズマ炎３の温度が急激に低下するため、混合造粒粉末５の溶融した液滴がそのまま気化しきれずに固化している。しかも、回収粉末の粒子径が非常に大きいとともに、気相反応が行われていないため、金属ＳｉとＳｉＯ２の混合物粒子状の粉末が多かった。 (Comparative Example 3)
The operation was performed under the same conditions as in Example 1 except that heating in the high-frequency induction heating furnace 19 was not performed.
Since the material is granulated, the material is melted in the plasma flame 3 because the raw material particle diameter is large. However, since the temperature of the plasma flame 3 rapidly decreases, the molten droplets of the mixed granulated powder 5 are solidified without being vaporized as they are. Moreover, since the particle diameter of the recovered powder is very large and no gas phase reaction is performed, a mixture of metal Si and SiO 2 in the form of particulate powder is large.
　（比較例４）
　プラズマ炎３の噴出速度を遅くするためプラズマガン先端部２ａのノズル１０の径を大きくした特殊なノズルを採用せず、通常のＤＣ（直流）プラズマ装置（日本ユテク製：ＳＧ-１００溶射ガン）を使用する以外は、実施例１と同じ条件で操業した。
　特殊なノズルを採用しない、通常のＤＣ（直流）プラズマ装置では、溶融液滴の飛翔速度が非常に早く、高周波誘導加熱炉１９での滞留時間が非常に短い。比較例３に比べると溶融液滴の気化はかなり行われているが、十分ではなかった。 (Comparative Example 4)
A normal DC (direct current) plasma device (manufactured by Nippon Yutec Corp .: SG-100 spray gun) is used instead of a special nozzle in which the diameter of the nozzle 10 at the tip 2a of the plasma gun is increased in order to slow down the ejection speed of the plasma flame 3. Was operated under the same conditions as in Example 1 except that.
In a normal DC (direct current) plasma apparatus that does not employ a special nozzle, the flying speed of molten droplets is very fast, and the residence time in the high-frequency induction heating furnace 19 is very short. Compared with Comparative Example 3, vaporization of the molten droplets was considerably carried out, but it was not sufficient.
　（比較例５）
　圧縮Ｎ２ガスによる一次急冷を行わず、高周波誘導加熱炉１９から出た高温度ガス（約１，７００℃）をそのまま、断熱二重管２３内に放出する以外は、実施例１と同じ条件で操業した。
　高温度のＳｉＯＸガスは、断熱二重管２３を通して水冷却サイクロン２４の雰囲気中に放出されるが、ガス流速が遅く殆どが断熱二重管２３内で析出固化するか、サイクロン内に入り込んだ粒子も水冷却サイクロン２４で沈降せず収率が非常に悪かった。 (Comparative Example 5)
The same conditions as in Example 1 except that the high-temperature gas (about 1,700 ° C.) discharged from the high-frequency induction heating furnace 19 is discharged as it is into the heat insulating double tube 23 without performing the primary quenching with the compressed N 2 gas. Operated at.
The high-temperature SiO X gas is released into the atmosphere of the water-cooled cyclone 24 through the heat insulating double tube 23, but the gas flow rate is slow and most of the gas is precipitated and solidified in the heat insulating double tube 23 or enters the cyclone. The particles also did not settle in the water cooled cyclone 24 and the yield was very bad.
１　ＤＣ（直流）プラズマ装置
２　プラズマガン
２ａ　プラズマガン先端部
３　プラズマ炎
４　粉末供給ノズル
５　混合造粒粉末
６　電極ホルダー
７　陰極
８　作動ガス通路
９　作動ガス
１０　ノズル（陽極）
１１　ウオータージャケット
１２　冷却水
１３　粉末造粒装置
１４　粉末供給装置
１５　黒鉛管（反応管）
１６　断熱材
１７　水冷石英管
１８　高周波誘導コイル
１９　高周波誘導加熱炉
２０　冷却装置
２２　リング状ノズル
２３　断熱二重管
２４　水冷却サイクロン
２５ａ　断熱二重管２３内で析出するＳｉＯＸ微粉末
２５ｂ　水冷却サイクロン２４で回収されるＳｉＯＸ粉末
２６　ホッパー
２７　バグフィルタ
２８　真空ポンプ
３０　熱交換器
３２　高圧ブロワー
３４　不活性ガス冷却装置 DESCRIPTION OF SYMBOLS 1 DC (direct current) plasma apparatus 2 Plasma gun 2a Plasma gun front-end | tip part 3 Plasma flame 4 Powder supply nozzle 5 Mixed granulated powder 6 Electrode holder 7 Cathode 8 Working gas passage 9 Working gas 10 Nozzle (anode)
11 Water jacket 12 Cooling water 13 Powder granulator 14 Powder feeder 15 Graphite tube (reaction tube)
16 Heat insulating material 17 Water-cooled quartz tube 18 High-frequency induction coil 19 High-frequency induction heating furnace 20 Cooling device 22 Ring-shaped nozzle 23 Heat-insulating double tube 24 Water-cooling cyclone 25a SiO X fine powder 25b deposited in the heat-insulating double tube 23 Water-cooling cyclone SiO X powder recovered at 24 26 Hopper 27 Bag filter 28 Vacuum pump 30 Heat exchanger 32 High pressure blower 34 Inert gas cooling device

Claims (23)

  1. 　金属Ｓｉ粉末とＳｉＯ2粉末との混合造粒粉末をプラズマ炎で加熱溶融させる工程と、
    　加熱溶融された前記混合造粒粉末の溶融液滴を加熱炉で気化させてＳｉＯX化反応を行わせる工程と、
    　生成された前記ＳｉＯXガスを不活性ガスで急冷却してＳｉＯX微粉末を析出させる工程と
    　を有することを特徴とするＳｉＯX粉末製造法。     A step of heating and melting a mixed granulated powder of metal Si powder and SiO 2 powder with a plasma flame;
    A step of evaporating molten droplets of the mixed granulated powder heated and melted in a heating furnace to perform a SiO x conversion reaction;
    SiO X powder production method characterized by a step of depositing a SiO X fine powder generated the SiO X gas is quenched with an inert gas.
  2. 　前記金属Ｓｉ粉末は、高純度（４Ｎ以上）Ｓｉ粉末であることを特徴とする請求項１記載のＳｉＯX粉末製造法。 The method for producing SiO x powder according to claim 1, wherein the metal Si powder is a high-purity (4N or more) Si powder.
  3. 　前記高純度（４Ｎ以上）Ｓｉ粉末は、半導体又は太陽電池用のシリコンウエーハ製造工程で発生する金属Ｓｉスラッジの再生品であることを特徴とする請求項２記載のＳｉＯX粉末製造法。 3. The method for producing SiO x powder according to claim 2, wherein the high-purity (4N or more) Si powder is a recycled product of metal Si sludge generated in a silicon wafer production process for semiconductors or solar cells.
  4. 　前記金属Ｓｉ粉末と前記ＳｉＯ2粉末とは、それぞれの平均粒子径Ｄ50が１０μｍ以下で、混合比率が、前記ＳｉＯX微粉末のＸ値が０．５～１．８になるように設定されることを特徴とする請求項１乃至請求項３の何れか記載のＳｉＯX粉末製造法。 The metal Si powder and the SiO 2 powder have an average particle diameter D 50 of 10 μm or less, and the mixing ratio is set so that the X value of the SiO X fine powder is 0.5 to 1.8. The method for producing SiO x powder according to any one of claims 1 to 3, wherein:
  5. 　前記金属Ｓｉ粉末と前記ＳｉＯ2粉末とは、それぞれの平均粒子径Ｄ50が５μｍ以下で、混合比率が、前記ＳｉＯX微粉末のＸ値が０．５～１．８になるように設定されることを特徴とする請求項１乃至請求項３の何れか記載のＳｉＯX粉末製造法。 The metal Si powder and the SiO 2 powder have an average particle diameter D 50 of 5 μm or less, and the mixing ratio is set so that the X value of the SiO X fine powder is 0.5 to 1.8. The method for producing SiO x powder according to any one of claims 1 to 3, wherein:
  6. 　前記混合造粒粉末は、噴霧乾燥法（スプレードライ）で平均粒子径Ｄ50が１０μｍ～５０μｍに造粒されることを特徴とする請求項１乃至請求項５の何れか記載のＳｉＯX粉末製造法。 6. The SiO x powder production according to claim 1, wherein the mixed granulated powder is granulated to an average particle diameter D 50 of 10 μm to 50 μm by a spray drying method (spray drying). Law.
  7. 　前記混合造粒粉末は、ＤＣ（直流）プラズマ装置又はＲＦ（高周波誘導）熱プラズマ装置にて発生する６，０００Ｋ（５，７２７℃）以上のプラズマ炎に吹き込まれて加熱溶融されることを特徴とする請求項１乃至請求項６の何れか記載のＳｉＯX粉末製造法。 The mixed granulated powder is heated and melted by being blown into a plasma flame of 6,000 K (5,727 ° C.) or more generated in a DC (direct current) plasma apparatus or an RF (high frequency induction) thermal plasma apparatus. The method for producing SiO x powder according to any one of claims 1 to 6.
  8. 　前記混合造粒粉末は、前記プラズマ炎の中での材料飛翔速度が、１５０ｍ／ｓｅｃ～３ｍ／ｓｅｃになるように噴出されることを特徴とする請求項１乃至請求項７の何れか記載のＳｉＯX粉末製造法。 The mixed granulated powder is ejected so that a material flight speed in the plasma flame is 150 m / sec to 3 m / sec. SiO x powder production method.
  9. 　前記加熱炉は、黒鉛ヒーター加熱炉又は高周波誘導加熱炉であり、前記プラズマ炎で加熱溶融された前記混合造粒粉末の混合溶融液滴を、更に２，０００Ｋ（１，７２７℃）以上に加熱気化させて、前記ＳｉＯXガスを生成させることを特徴とする請求項１乃至請求項８の何れか記載のＳｉＯX粉末製造法。 The heating furnace is a graphite heater heating furnace or a high frequency induction heating furnace, and the mixed molten droplets of the mixed granulated powder heated and melted by the plasma flame are further heated to 2,000 K (1,727 ° C.) or more. The method for producing SiO x powder according to any one of claims 1 to 8, wherein the SiO x gas is generated by vaporization.
  10. 　前記加熱炉で気化された前記ＳｉＯXガスは、前記加熱炉の出口において、圧縮不活性ガスで８００℃以下に急冷却され、０．０１μｍ～１０μｍのＳｉＯX微粉末を析出することを特徴とする請求項１乃至請求項９の何れか記載のＳｉＯX粉末製造法。 The SiO x gas vaporized in the heating furnace is rapidly cooled to 800 ° C. or less with a compressed inert gas at the outlet of the heating furnace to deposit 0.01 μm to 10 μm SiO x fine powder. The method for producing SiO x powder according to any one of claims 1 to 9.
  11. 　前記加熱炉は、３０ｋＰａ～８０ｋＰａの減圧下で運転されることを特徴とする請求項１乃至請求項１０の何れか記載のＳｉＯX粉末製造法。 The method for producing a SiO x powder according to any one of claims 1 to 10, wherein the heating furnace is operated under a reduced pressure of 30 kPa to 80 kPa.
  12. 　析出した前記ＳｉＯX微粉末を水冷却サイクロンにて冷却して回収する工程を更に有することを特徴とする請求項１乃至請求項１０の何れか記載のＳｉＯX粉末製造法。 The method for producing SiO x powder according to any one of claims 1 to 10, further comprising a step of cooling and collecting the deposited fine SiO x powder with a water-cooled cyclone.
  13. 　前記水冷却サイクロンは、外周を水冷却し、８００℃以下に一次冷却された前記ＳｉＯX微粉末及び不活性ガスを吹き込み、前記ＳｉＯXガスを２００℃以下に冷却し、前記ＳｉＯX微粉末の粒子径を成長させて回収することを特徴とする請求項１２記載のＳｉＯX粉末製造法。 The water cooling cyclone, the outer periphery was water cooled, blowing the SiO X powder and inert gas primary cooling to 800 ° C. or less, the cooled SiO X gas to 200 ° C. or less, the SiO X fine powder 13. The method for producing SiO x powder according to claim 12, wherein the particle diameter is grown and recovered.
  14. 　回収された前記ＳｉＯX微粉末の平均粒子径Ｄ50は、１μｍ～２０μｍであることを特徴とする請求項１３記載のＳｉＯX粉末製造法。 14. The method for producing SiO x powder according to claim 13, wherein the average particle diameter D 50 of the collected SiO x fine powder is 1 μm to 20 μm.
  15. 　前記水冷却サイクロンで未回収の前記ＳｉＯX微粉末をバグフィルタで回収集塵する工程を更に有することを特徴とする請求項１２乃至請求項１４の何れか記載のＳｉＯX粉末製造法。 The method for producing SiO x powder according to any one of claims 12 to 14, further comprising a step of collecting dust by collecting the SiO x fine powder unrecovered in the water-cooled cyclone with a bag filter.
  16. 　前記バグフィルタで回収集塵後のクリーンな排気ガスを、熱交換器で常温まで冷却し、更に高圧ブロワーにて昇圧し、前記加熱炉の出口において、前記加熱炉で気化された前記ＳｉＯXガスを急冷する前記不活性ガスとして循環使用することを特徴とする請求項１５記載のＳｉＯX粉末製造法。 Clean exhaust gas after dust collected by the bag filter is cooled to room temperature by a heat exchanger, further pressurized by a high pressure blower, and the SiO x gas vaporized in the heating furnace at the outlet of the heating furnace The method for producing SiO x powder according to claim 15, wherein the inert gas for rapidly cooling is used in a circulating manner.
  17. 　プラズマ炎を噴出するプラズマガンを備えるＤＣ（直流）プラズマ装置又はＲＦ（高周波誘導）熱プラズマ装置と、
    　金属Ｓｉ粉末とＳｉＯ2粉末との混合造粒粉末を前記プラズマ炎中に噴霧する粉末供給装置と、
    　前記プラズマ炎にて加熱溶融された前記混合造粒粉末の溶融液滴を気化させてＳｉＯX化反応を行わせる加熱炉と、
    　生成された前記ＳｉＯXガスを不活性ガスで急冷却してＳｉＯX微粉末を析出させる冷却装置と
    　を有することを特徴とするＳｉＯX粉末製造装置。     A DC (direct current) plasma device or an RF (radio frequency induction) thermal plasma device comprising a plasma gun for ejecting a plasma flame;
    A powder supply device for spraying mixed granulated powder of metal Si powder and SiO 2 powder into the plasma flame;
    A heating furnace for vaporizing the molten droplets of the mixed granulated powder heated and melted by the plasma flame to perform a SiO x conversion reaction;
    SiO X powder production apparatus characterized by comprising a cooling device for precipitating SiO X fine powder generated the SiO X gas is quenched with an inert gas.
  18. 　前記プラズマガンは、前記プラズマ炎の中での材料飛翔速度が、１５０ｍ／ｓｅｃ～３ｍ／ｓｅｃになるようにノズルに速度調整部を設けていることを特徴とする請求項１７記載のＳｉＯX粉末製造装置。 18. The SiO x powder according to claim 17, wherein the plasma gun is provided with a speed adjusting portion at a nozzle so that a material flight speed in the plasma flame is 150 m / sec to 3 m / sec. Manufacturing equipment.
  19. 　前記加熱炉は、黒鉛ヒーター加熱炉又は高周波誘導加熱炉であり、前記プラズマ炎で加熱溶融された前記混合造粒粉末の混合溶融液滴を、更に２，０００Ｋ（１，７２７℃）以上に加熱気化させて、前記ＳｉＯXガスを生成させることを特徴とする請求項１７又は請求項１８記載のＳｉＯX粉末製造装置。 The heating furnace is a graphite heater heating furnace or a high frequency induction heating furnace, and the mixed molten droplets of the mixed granulated powder heated and melted by the plasma flame are further heated to 2,000 K (1,727 ° C.) or more. vaporized, SiO X powder production apparatus as claimed in claim 17 or claim 18 further characterized in that to produce the SiO X gas.
  20. 前記冷却装置は、前記加熱炉で気化された前記ＳｉＯXガスに不活性ガスを吹き付けて急冷するリング状のノズルを有することを特徴とする請求項１７乃至請求項１９の何れか記載のＳｉＯX粉末製造装置。 The SiO x according to any one of claims 17 to 19, wherein the cooling device includes a ring-shaped nozzle that blows an inert gas onto the SiO x gas vaporized in the heating furnace to quench the gas. Powder manufacturing equipment.
  21. 　析出したＳｉＯX微粉末を冷却して回収する水冷却サイクロンを更に有することを特徴とする請求項１７乃至請求項１９の何れか記載のＳｉＯX粉末製造装置。 SiO X powder production apparatus according to any one of claims 17 to claim 19, SiO X fine powder precipitated and further comprising a water cooling cyclone to recover by cooling.
  22. 　前記水冷却サイクロンで未回収の前記ＳｉＯX微粉末を回収集塵するバグフィルタを更に有することを特徴とする請求項２０記載のＳｉＯX粉末製造装置。 21. The apparatus for producing SiO x powder according to claim 20, further comprising a bag filter for collecting and collecting the uncollected SiO x fine powder by the water-cooled cyclone.
  23. 　前記バグフィルタで回収集塵後のクリーンな排気ガスを常温まで冷却する熱交換器と、前記熱交換器で常温まで冷却された前記クリーンな排気ガスを昇圧して前記冷却装置のリング状ノズルに循環する高圧ブロワーとを備える不活性ガス冷却装置を更に有することを特徴とする請求項２２記載のＳｉＯX粉末製造装置。
          A heat exchanger that cools the clean exhaust gas after dust collection by the bag filter to room temperature, and pressurizes the clean exhaust gas cooled to room temperature by the heat exchanger to the ring-shaped nozzle of the cooling device SiO X powder production apparatus according to claim 22, further comprising an inert gas cooling system comprising a high pressure blower circulating.
PCT/JP2014/003961 2013-07-30 2014-07-28 Siox powder manufacturing process and siox powder manufacturing apparatus WO2015015795A1 (en)

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CN106966398A (en) * 2017-04-19 2017-07-21 合肥科晶材料技术有限公司 A kind of two source controllable SiO production systems and production method
CN108821292A (en) * 2017-05-05 2018-11-16 储晞 It is a kind of to produce the method and device for aoxidizing sub- silicon
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CN109360942A (en) * 2018-11-22 2019-02-19 中南大学 A method of negative electrode of lithium ion battery is prepared based on recycling solar cell
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WO2021026958A1 (en) * 2019-08-12 2021-02-18 东北大学 Method for preparing white carbon black by means of crystalline silicon diamond wire cut waste
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WO2017085908A1 (en) * 2015-11-18 2017-05-26 信越化学工業株式会社 Negative electrode active material, mixed negative electrode active material, negative electrode for non-aqueous electrolyte secondary battery, lithium ion secondary battery, method for producing negative electrode active material, and method for producing lithium ion secondary battery
JP2017097955A (en) * 2015-11-18 2017-06-01 信越化学工業株式会社 Negative electrode active substance, mixed negative electrode active substance material, negative electrode for nonaqueous electrolyte secondary battery, lithium ion secondary battery, manufacturing method of negative electrode active material, and manufacturing method of lithium ion secondary battery
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CN106966398A (en) * 2017-04-19 2017-07-21 合肥科晶材料技术有限公司 A kind of two source controllable SiO production systems and production method
CN106966398B (en) * 2017-04-19 2023-08-08 合肥科晶材料技术有限公司 Two-source controllable SiO production system and production method
CN108821292A (en) * 2017-05-05 2018-11-16 储晞 It is a kind of to produce the method and device for aoxidizing sub- silicon
WO2018221268A1 (en) * 2017-06-01 2018-12-06 信越化学工業株式会社 Negative-electrode active substance, mixed negative-electrode active substance material, and method for manufacturing negative-electrode active substance particles
JP2018206560A (en) * 2017-06-01 2018-12-27 信越化学工業株式会社 Negative electrode active substance, mixed negative electrode active substance material, and method for manufacturing particles of negative electrode active substance
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US11283060B2 (en) 2017-06-01 2022-03-22 Shin-Etsu Chemical Co., Ltd. Negative electrode active material, mixed negative electrode active material, and method for producing negative electrode active material particle
CN109360942B (en) * 2018-11-22 2021-04-13 中南大学 Method for preparing lithium ion battery cathode based on recycled solar battery
CN109360942A (en) * 2018-11-22 2019-02-19 中南大学 A method of negative electrode of lithium ion battery is prepared based on recycling solar cell
WO2021026958A1 (en) * 2019-08-12 2021-02-18 东北大学 Method for preparing white carbon black by means of crystalline silicon diamond wire cut waste
CN110935881A (en) * 2019-12-30 2020-03-31 佛山市中研非晶科技股份有限公司 Amorphous nanocrystalline powder baking equipment and use its magnetic powder core production line
CN111889031A (en) * 2020-07-29 2020-11-06 常州华芯装备工程有限公司 Production device for preparing SiO powder
CN114349011A (en) * 2022-01-14 2022-04-15 宁波广新纳米材料有限公司 Preparation method of nano-sized silicon monoxide powder
CN116678217A (en) * 2023-08-03 2023-09-01 四川士达贸易有限公司 Graphitization process and equipment for lithium battery cathode material
CN116678217B (en) * 2023-08-03 2023-10-13 四川士达贸易有限公司 Graphitization process and equipment for lithium battery cathode material
CN117001004A (en) * 2023-09-28 2023-11-07 西安赛隆增材技术股份有限公司 Microwave plasma powder making device and method
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