JPH01126213A - Production of graphite powder and device therefor - Google Patents

Abstract

PURPOSE:To improve purity and particle size distribution of graphite powder without mechanical pulverizing of a starting raw material by using silicon carbide powder as the starting raw material and making it react with at least one of gaseous halogen and gaseous halide at high temp. CONSTITUTION:The following heating and decomposing processes (a), (b) are used. In other words, (a) silicon carbide powder is heated at >=1,000 deg.C and (b) at least one of gaseous halogen (e.g. gaseous chlorine) and gaseous halide (e.g. gaseous hydrochloric acid) is fed to the silicon carbide powder heated at >=1,000 deg.C and thereby this silicon carbide powder is decomposed and graphite powder is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Objectives of the Invention [Industrial Application Field] The present invention relates to a graphite powder manufacturing method and a graphite powder manufacturing apparatus, and particularly to a starting point! ! 100% silicon carbide powder as X material
The present invention relates to a method and apparatus for producing graphite powder, in which graphite powder is produced by heating to a temperature of 0° C. or higher and decomposing it using at least one of a halogen gas and a halide gas.

[Prior Art] Conventionally, this type of graphite powder production method and graphite powder J? I
For each St, (i) natural graphite or artificial graphite is mechanically crushed using a ball mill or the like, or (
ii) It has been proposed to create expanded graphite and then freeze and crush it using a medium such as acetone.

[Problems to be Solved] However, in conventional graphite powder manufacturing methods and graphite powder manufacturing equipment, natural graphite, artificial graphite, or expanded graphite as a starting material is simply crushed using mechanical crushing means. There are disadvantages that impurities contained in the raw material remain as they are and impurities are mixed in due to wear of the crushing means, etc., and furthermore, there is a disadvantage that the purity of graphite powder cannot be improved, and there is also a disadvantage that the production fi rate cannot be improved. 11) The particle size distribution at the base cannot be changed, since the classification of the graphite powder must be carried out at the final stage, that is, at the completion of pulverization.

Therefore, the present invention uses silicon carbide powder as a starting material, classifies it, and then decomposes at least one of halogen gas and halide gas to generate graphite powder, thereby avoiding mechanical pulverization and improving the purity and particle size distribution of graphite powder. It is an object of the present invention to provide a graphite powder manufacturing method and a graphite powder manufacturing apparatus by modifying the method and improving the production rate.

(2) Structure of the invention [Means for solving the problems] The means for solving the problems provided by the present invention are as follows:
a heating step of heating silicon carbide powder to a temperature of 1000°C or higher; (b) supplying at least one of a halogen gas and a halide gas to the silicon carbide powder heated to a temperature of +ooo°C or higher to carry out the carbonization; and a decomposition step of decomposing silicon powder to generate graphite powder.''

Another solution to the problem provided by the present invention is.

``(a) a graphite crucible containing gas-permeable upper and lower lids for containing silicon carbide powder;

(b) a gas supply device that supplies at least one of a halogen gas and a halide gas to the silicon carbide powder through the lower lid of the graphite crucible;

(c) a heating device that heats the silicon carbide powder to a temperature of 1000° C. or higher to cause it to be decomposed by at least one of the halogen gas and the halide gas to produce graphite powder. Graphite powder manufacturing equipment.

[Function] The graphite powder manufacturing method according to this 9.1 JI involves heating silicon carbide powder to a temperature of 1000°C or higher in the heating step, and converting the silicon carbide powder heated to a temperature of 1000°C or higher in the decomposition step into halogen. The function is to decompose with at least one of the gas and the halide gas, thereby producing graphite powder. It has the effect of avoiding mechanical crushing of the rX material, has the effect of improving the production efficiency of graphite powder, and improves the particle size distribution of graphite powder as a classifying part in the state of silicon carbide powder with a large specific gravity. It also acts to improve the purity of graphite powder.

Further, in the graphite powder manufacturing apparatus according to the present invention, silicon carbide powder is stored in a graphite crucible that includes a gas-permeable upper lid and a lower lid, and a halogen gas and a halide gas are released through the lower lid. at least one of the halogen gas and the halide gas is supplied by a gas supply device, and the silicon carbide powder is heated to a temperature of 1000° C. or higher by a heating device to be decomposed by at least one of the halogen gas and the halide gas, thereby producing graphite powder. It acts to avoid mechanical crushing of the starting material, and as a result, improves the production efficiency of graphite powder and improves the particle size of graphite powder by making it possible to classify silicon carbide powder with a large specific gravity. It acts to improve the distribution and also acts to improve the purity of graphite powder.

[Example] Next, the present invention will be specifically described with reference to Examples.

FIG. 1 is a side view showing a graphite powder manufacturing apparatus for carrying out an embodiment of the graphite powder manufacturing method according to the present invention.

FIG. 2 is a graph diagram showing the particle size distribution of graphite powder manufactured by carrying out the graphite powder manufacturing method according to the present invention using the graphite powder manufacturing apparatus shown in FIG.

First, the configuration of a graphite powder manufacturing apparatus for carrying out an embodiment of the graphite powder manufacturing method according to the present invention will be described in detail with reference to the jSf diagram.

This is the graphite powder manufacturing apparatus of the present invention, which includes a furnace core tube side, a high-frequency heating coil concave disposed around the furnace core tube, and a silicon carbide powder disposed inside the furnace core tube. A graphite crucible for accommodating the bundle, an induction heating device for heating the silicon carbide powder stored in the graphite crucible, and a furnace core tube. It includes a carbon felt U disposed between the inner circumferential surface and the outer circumferential surface similar to that of an induction heating device for heat retention and insulation.

The furnace core tube includes a furnace core tube body 21 surrounded by two high-frequency heating coils 4, a furnace core tube lower cover 22 that closes the upper end opening of the furnace core tube body 21, and an L of the furnace core tube body 21. It includes a furnace core tube upper lid 23 that closes the end opening. One end of the furnace core tube lower lid 22 is connected to a gas supply device 1 (Iji not shown) for supplying at least one of halogen gas (for example, chlorine gas) and halide gas (for example, hydrochloric acid gas). The other end of the gas supply pipe 2ZA is penetrated therethrough.

One end of the furnace core tube upper cover 23 is provided with an appropriate reduced pressure. The other end of a gas exhaust pipe 23^ communicated with the gas discharge pipe 23 (not shown) is penetrated therethrough.

The graphite crucible includes a cylindrical graphite crucible main body 41 having an upper end opening and an upper end opening, a graphite crucible lower cover 42 disposed at the upper end opening of the graphite crucible main body 41, and a graphite crucible main body 4! It includes a graphite crucible upper cover 43 disposed at the upper end f4 opening of the graphite crucible. The graphite crucible lower lid 42 and the graphite crucible upper lid 43 supply at least one of the halogen gas and halide gas supplied via the gas supply pipe 22A to the silicon carbide powder, and supply the halogen gas and the halide gas to the silicon carbide powder. A gas permeable material (for example, a carbon filter) is used to discharge the generated gas containing the silicon halide gas generated by the reaction between at least one of the gases and the silicon carbide powder bundle portion through the gas exhaust pipe 23A. Each of them is included.

If desired, the silicon carbide powder is pulverized using a suitable pulverizing device (for example, a ball mill) and classified as appropriate. This is based on the fact that the particle size of the graphite powder is similar to the particle size of the silicon carbide powder bundle, which is the starting material. Furthermore, since it is possible to classify the starting material, silicon carbide powder, which has a high specific gravity, the classification accuracy of the graphite powder can be improved compared to the case where the graphite powder, which is the final product, has a low specific gravity.

The view of the inductive heating device is that an upper electrode 61 for induction heating is disposed between the inner circumferential surface of the furnace core tube body 21 and the outer circumferential surface of the graphite crucible body 41, and a lower end portion of the induction heating electrode 61. It includes a lower lid 62 provided, an upper lid 63 provided at the upper end of the induction heating electrode 61, and a support 64 for jamming the graphite crucible against the lower ri 62. At the bottom '462,
In order to guide at least one of the halogen gas and halide gas supplied via the gas supply pipe 22^ to the graphite crucible lower cover 42, an appropriate number of gas holes 62A are provided. Further, in the upper lid 63, a gas containing a silicon halide gas generated by a reaction between at least one of a halogen gas and a halide gas and a silicon carbide powder is discharged from the graphite crucible; An appropriate number of gas holes 63A are provided to guide the gas holes 23A.

Further, the graphite powder manufacturing method according to the present invention will be explained in detail while explaining the action of the pressure of the graphite powder manufacturing apparatus according to the present invention shown in FIG.

A suitable silicon carbide material is pulverized using a suitable pulverizing device such as a ball mill, and then classified as desired to produce silicon carbide powder.

Silicon Carbide Powder Co., Ltd. temporarily opened the graphite crucible L, 14:1, and housed the induction heating device in the furnace core tube in a state where an appropriate amount was accommodated in the graphite crucible. .

After the graphite crucible is placed on the lower lid 62 via the support 64, the upper lid 63 is closed.

Furthermore, an appropriate amount of carbon felt 4 is placed on the upper lid 6, and the furnace core tube upper lid 23 is closed.

After closing the furnace core tube upper lid 23, an inert gas (for example, argon gas, nitrogen gas, etc.) is supplied by a gas supply device (not shown) through the gas supply pipe 22A, and thereby the carbon felt U and the lower lid are closed. The inert gas is supplied to the silicon carbide powder contained in the graphite crucible through the gas hole 62A of No. 62 and the lower graphite crucible M42. Silicon carbide powder is fluidized for this purpose.

After that, high frequency heating coil 2! ! Then, an appropriate voltage is supplied to the induction heating electrode 61 to heat the silicon carbide powder housed in the graphite crucible to a temperature of 1000° C. or higher.

After reaching a temperature of 1000°C or more, the inert gas being supplied via the gas supply pipe 22A is shut off, and halogen gas (for example, chlorine gas) and halide gas (for example, hydrochloric acid gas) are newly supplied. A gas supply device (not shown) starts supplying at least one of the gases to the silicon carbide powder company. By continuing to supply at least one of halogen gas and halide gas for a predetermined period of time and reacting with silicon carbide powder to convert the silicon carbide powder into a product gas containing silicon halide gas, silicon carbide can be produced. Powder is decomposed into graphite powder.

After sufficient time has elapsed for decomposition of the silicon carbide powder, at least one of the halogen gas and halide gas supplied via the gas supply pipe 22A is shut off, and a new inert gas (e.g. Argon gas or nitrogen gas) is supplied to scavenge at least one of the halogen gas and the halide gas and the produced gas containing the silicon halide gas in the furnace core tube. The voltage supplied to the induction heating electrode 61 and the high-frequency heating coil η is cut off, and after waiting for the temperature inside the furnace core tube to reach room temperature, the furnace core tube upper cover 23 is opened and the graphite crucible is taken out. By opening the graphite crucible top 443 of the graphite crucible, graphite powder is taken out and recovered from the graphite crucible.

In addition, the graphite powder manufacturing method and graphite powder manufacturing apparatus according to the present invention will be explained in detail by citing specific numerical values so that the graphite powder manufacturing method and apparatus can be understood in detail.

(Example) Silicon carbide powder having an average particle size L of 34 m and a maximum particle size of 3.3 pm obtained by milling and classifying an appropriate amount of silicon carbide material was placed in a graphite crucible as a starting material. were housed in the furnace core tube chamber as shown in Figure 1.

The tR silicon oxide powder 50 is supplied with gas by a gas supply device.
i? A fluidized bed was created by supplying argon gas to the graphite crucible concave via 22A.

After that, high frequency heating coil and induction heating electrode 6
An appropriate voltage was supplied to 1, and the silicon carbide powder housed in the graphite crucible was heated to a temperature of 1600''c.

After Silicon Carbide Powder Co., Ltd. reached 110"C, the argon gas supplied through the gas supply pipe 22A was cut off, and the gas supply device began supplying chlorine gas. As a result, Silicon Carbide Powder Co., Ltd.
It was decomposed into SiC14 (gas) and SiC (powder) to produce graphite powder.

After 15 hours have elapsed, the chlorine gas supplied via the gas supply pipe 22A is shut off, and nitrogen gas is newly supplied at the gas supply position 9 to remove the chlorine gas and chloride that had filled the inside of the furnace core tube. The silicon gas was scavenged. The appropriate current applied to the high-frequency heating coil and the induction heating electrode 61 is cut off, and after waiting for the temperature of the graphite crucible to drop to room temperature, the furnace core tube upper cover 23 is opened and the graphite crucible is heated. Graphite powder was recovered from the coal.

The recovered graphite powder has a bulk density of 0.98 g/cm'', an average particle size of 1.2 #Lm, and a maximum particle size of 3.2 #Lm.
It was pm. Further, the particle size fraction # (here cumulative percentage) of the recovered graphite powder was as shown by the solid line in FIG.

In addition, the recovered graphite powder is free of all impurities (e.g. Ni
, Fe, Mn, Mg, Cu, Cr, Na, tca+A
The concentration of I*V, s, O, etc.) was only 2 ppm.

(Comparative example) Graphite powder recovered by crushing natural graphite powder in a roll mill for 50 hours has a bulk density of 1.98 to L1g/c■3
and the average particle size is 1.2 gm and the maximum particle size is 12)
It was hm. Further, the particle size distribution (here cumulative percentage) of the graphite powder recovered at this time was as shown by the broken line in FIG.

In addition, the recovered graphite powder is free of all impurities (e.g. Ni
, Fe, Iin, 11g, Cu, Cr, Na, Ca
, AI, V, S, O) temperature was SOOOppm.

(3) Effects of the Invention As is clear from the above, the method for producing graphite powder tA according to the present invention is as follows.

(a) +& A heating step of heating silicon carbide powder to a temperature of 1000°C or higher; (b) Supplying at least one of a halogen gas and a halide gas to the silicon carbide powder heated to a temperature of 1000°C or higher. and a decomposition step of decomposing the silicon carbide powder to generate graphite powder, (i) the effect of avoiding mechanical crushing of the starting material is achieved, and as a result (iυ graphite powder generation). Effects that can improve efficiency (iii)
It has the effect of being able to improve the purity of graphite powder and (iv) adjusting the particle size distribution of silicon carbide powder with a large specific gravity, thereby making it possible to adjust the particle size of graphite powder and, in turn, changing the particle size distribution.

Further, the graphite powder manufacturing apparatus according to the present invention includes (a) a graphite crucible that includes a gas-permeable upper cover and a lower cover and accommodates silicon carbide powder;

(b) Gas supply for supplying at least one of halogen gas 3 and halide gas to the silicon carbide powder through the lower lid of the graphite crucible? With tW1.

(c) a heating device that heats the silicon carbide powder to a temperature of 1000° C. or higher to cause it to be decomposed by at least one of the halogen gas and the halide gas to produce graphite powder; It has the effects of (+) to (iv).

dir+i0L it::”,’,’; Theory Riwa

[Brief explanation of the drawing]

Figure 2 is a sectional view showing a graphite powder manufacturing apparatus for carrying out an embodiment of the graphite powder manufacturing method according to the present invention, and Figure 2 is a sectional view showing a graphite powder manufacturing apparatus for carrying out the graphite powder manufacturing method according to the present invention as shown in Figure 1. FIG. 2 is a graph diagram showing the particle size distribution of graphite powder produced by performing the process with the apparatus.艮・・・・・・・・・・・・Graphite powder manufacturing method court・
・・・・・・・・・・・・Furnace core tube 21・・・・・・・
・・・・・・Furnace tube body 22・・・・・・・・・Furnace core tube lower cover 22＾・・・・・・・・・Gas supply pipe 23・
......Furnace core tube top cover 23A...
......For gas discharge pipe......Coil for high frequency heating......Graphite crucible 41... ...Graphite crucible body 4
2・・・・・・・・・Graphite crucible lower 443...
......Graphite crucible top lid 50...
・・・・・・Silicon carbide powder 60・・・・・・・・・
...Induction heating device 61...Induction heating electrode 62...Lower lid 62A... Gas hole 63...I:, Lid 63A...
...... Gas hole 64 ...... Support body

Claims (2)

[Claims] (1) (a) A heating step of heating silicon carbide powder to a temperature of 1000°C or higher; (b) At least one of a halogen gas and a halide gas to the silicon carbide powder heated to a temperature of 1000°C or higher. a decomposition step of supplying silicon carbide powder to decompose the silicon carbide powder to produce graphite powder. (2) (a) a graphite crucible containing gas permeable upper and lower lids for accommodating silicon carbide powder; and (b) a graphite crucible for storing silicon carbide powder through the lower lid of the graphite crucible. a gas supply device that supplies at least one of halogen gas and halide gas; (c) heating the silicon carbide powder to a temperature of 1000° C. or higher; 1. A graphite powder manufacturing device comprising: a heating device for decomposing graphite powder to generate graphite powder.