JP2009008357A - Cycle purge method of vaporizing chamber for metal vaporization - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of keeping a vaporizing chamber for metal vaporization installed in a heating furnace over a long time without generating a crack. <P>SOLUTION: The vaporizing chamber 2 for metal vaporization installed in the heating furnace 1 is formed of ceramics. A process of respectively isolating the vaporization chamber from a supply pipe 8 for supplying a purge gas to the vaporizing chamber 2 and a delivery pipe 4 while the heating furnace 1 is operated and stopped after finishing a process of vaporizing metal in the vaporizing chamber by heating, and delivering the produced vaporized gas of the metal to a vaporized gas consumption device 3 through a delivery pipe 4 connecting the vaporizing chamber 2 to the vaporized gas consumption device 3, and a decompression and purge gas supply process of vacuum-decompressing the vaporizing chamber 2 through an exhaust pipe 6 connecting the vaporizing chamber 2 to a decompression device 5, and thereafter supplying the purge gas to the vaporizing chamber 2 through the supply pipe 8 are repeatedly continuously executed multiple number of times in that order. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cycle purge method for a vaporizing chamber for metal vaporization installed in a heating furnace.

Patent Document 1 discloses a heating furnace using a ceramic vaporizing chamber such as alumina as a furnace for heating to several hundreds of degrees Celsius, but does not disclose anything about vaporizing a metal in the vaporizing chamber.
Japanese Patent Laid-Open No. 61-286264

  In general, in an apparatus for supplying a gas by dissolving and vaporizing a metal (such as zinc), it is preferable to perform melting and vaporization in a ceramic container from the viewpoint of heat resistance and contamination with impurities. Yes.

However, as a result of the study by the present inventors, when a metal (for example, zinc) is melted and vaporized by heating using a ceramic vaporization chamber, the metal enters a minute hole on the ceramic surface, which is the vaporization chamber, It became clear that after the operation was stopped, the metal was solidified by cooling the vaporization chamber, and when the temperature was raised again after operation, the solidified metal expanded and expanded the minute hole. If the solidification / cooling is repeated several times, the minute hole becomes a crack, which leads to breakage of the ceramic.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for maintaining a vaporizing chamber for metal vaporization installed in a heating furnace over a long period without generating cracks.

That is, the present invention is a cycle purge method for a vaporizing chamber for metal vaporization installed in a heating furnace,
The vaporization chamber is formed of ceramics;
Finishing the process of vaporizing the metal in the vaporizing chamber by heating and sending the generated vaporized metal to the vaporized gas consuming device through a delivery pipe connected to the vaporized chamber and connecting the vaporized chamber and the vaporized gas consuming device. Until the furnace is shut down
Shutting off the vaporization chamber from a supply pipe connected to the vaporization chamber and supplying the purge gas to the vaporization chamber and the delivery pipe;
A pressure reducing and purging gas supplying step for supplying a purge gas to the vaporizing chamber through the supply pipe after vacuuming the vaporizing chamber through a discharge pipe connected to the vaporizing chamber and connecting the vaporizing chamber and the pressure reducing device in this order. ,
In addition, the present invention provides a cycle purging method for a vaporizing chamber for metal vaporization in which the depressurization and purge gas supply steps are continuously repeated a plurality of times.

In the present invention, the vaporization chamber is kept in the high temperature state before the heating furnace including the ceramic vaporization chamber in the high temperature state (hereinafter sometimes simply referred to as “vaporization chamber”) is shut down to cool the vaporization chamber. Is disconnected from the vaporized gas consuming device, the purge gas supply pipe, and the like, and the vaporized chamber is depressurized at once by evacuation by a depressurizing device. After maintaining the depressurized state for a certain time, the depressurization is stopped, and the purge gas is supplied into the vaporizing chamber through the purge gas supply pipe.
This purge gas supply process is a process of supplying a purge gas into the vaporization chamber and pressurizing the vaporization chamber. In the purge gas supply process, after the decompression state is maintained for a certain period of time and the decompression is stopped, the purge gas is first flowed into the vaporization chamber to exhaust the atmospheric gas, and then the exhaust pipe connecting the decompression device and the vaporization chamber is shut off. Thus, it is preferable that the vaporizing chamber is pressurized by supplying the purge gas through the purge gas supply pipe.
Then, after the purge gas supply step, the exhaust pipe connecting the decompression device and the vaporization chamber is opened again.
As described above, the decompression, pressurization, and exhaust opening are performed as a single cycle, preferably, the decompression, purge release, and purge blowing are performed repeatedly, and the pressurization and exhaust opening are performed as a single cycle. By reducing the pressure in the vaporizing chamber, the residual metal that has entered the minute hole is gasified, and is removed by blowing a purge gas. When the vaporizing chamber is pressurized, the purge gas spreads through the minute holes in the vaporizing chamber, and by performing vacuum decompression at once from the pressurized state, the residual zinc that has entered the minute holes can be efficiently removed.
Even if the heating furnace is cooled and reheated after such a process, the metal that expands the minute hole is almost free from the ceramic surface, so cracks do not occur, and there is no need to replace the ceramic vaporization chamber, reducing running costs. There is an effect.

  Further, a cooling trap may be arranged in the middle of the exhaust pipe connecting the decompression device and the vaporizing chamber. The vaporized and removed metal is condensed and collected in the cooling trap portion, and the metal can be easily recovered.

  ADVANTAGE OF THE INVENTION According to this invention, the vaporization chamber for metal vaporization installed in the heating furnace can be maintained over a long period, without generating a crack.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a cycle purge method for a metal vaporization chamber according to the present invention (hereinafter abbreviated as “cycle purge method”) will be described in detail with reference to the drawings. Hereinafter, although the example which uses zinc as a metal to be heat treated is shown, the present invention is not limited to this.

  FIG. 1 is a longitudinal sectional view showing a schematic configuration diagram of an embodiment example of a vaporization chamber installed in a heating furnace, which performs the cycle purge method according to the present invention.

As shown in FIG. 1, a ceramic vaporizing chamber 2 is installed in the heating furnace 1, and the ceramic vaporizing chamber 2 includes a delivery pipe 4 connecting the ceramic vaporizing chamber 2 and the vaporized gas consuming device 3, ceramic vaporizing. The exhaust pipe 6 that connects the chamber 2 and the vacuum pump 5 that is a decompression device, and the supply pipe 8 that connects the ceramic vaporizing chamber 2 and the purge gas supply unit 7 are provided. The installation position and installation form of the ceramic vaporizing chamber 2 in the heating furnace 1 are not particularly limited. The delivery pipe 4, exhaust pipe 6 and supply pipe 8 are provided with on-off valves 9, 10, 11 respectively.
Further, in FIG. 1, a cooling trap 12 is provided between the vacuum pump 5 and the on-off valve 10 in the middle of the exhaust pipe 6.

Next, the cycle purge method according to the present invention will be described.
In the cycle purge method of the present embodiment, zinc 13 is introduced into a ceramic boat 14 as a metal to be heat-treated in a ceramic vaporization chamber 2 installed in the heating furnace 1, and the temperature in the vaporization chamber is set to about 950 ° C. Dissolve and vaporize zinc. Further, the carrier gas is supplied into the ceramic vaporizing chamber 2 through the supply pipe 8 while the zinc is dissolved and vaporized by heating. The carrier gas is not particularly limited as long as it is an inert gas, and examples thereof include N ₂ gas, He gas, and Ar gas. As the heat source 15, a high-temperature Kanthal heater (manufactured by Sandvik) can be used.

During the vaporization of zinc, the on-off valve 9 is opened, and the zinc gas vaporized in the ceramic vaporization chamber 2 is sent out to the gas gas consumption device 3 through the delivery pipe 4.
After the vaporization of zinc in the ceramic vaporizing chamber 2 is completed, the on-off valves 9 and 11 are closed, and the ceramic vaporizing chamber 2 is shut off from the delivery pipe 4 and the supply pipe 8.

  Next, the on-off valve 10 is opened, and the inside of the ceramic vaporizing chamber 2 that is cut off from the delivery pipe 4 and the supply pipe 8 is vacuum-depressurized through the discharge pipe 6. At this time, the inside of the ceramic vaporizing chamber 2 is set to a high temperature of about 1000 ° C. In this state, the residual zinc clogged in the microholes in the ceramic furnace wall is vaporized. Even if there is zinc in a molten state adhering to the minute hole, the residual zinc in the minute hole is vaporized and removed by performing vacuum decompression.

After maintaining the depressurized state for a certain time, the depressurization is stopped, the on-off valve 11 is opened, the purge gas is supplied to the ceramic vaporizing chamber 2, and the atmospheric gas in the vaporizing chamber 2 is exhausted. At this time, the zinc gas which has been vaporized by vacuum depressurization and remains in the vaporization chamber is removed by blowing a purge gas. The purge gas is not particularly limited as long as it is inert gas, N ₂ gas, He gas, Ar gas, and the like. Then, the on-off valve 10 is closed and the inside of the ceramic vaporizing chamber 2 is pressurized. After pressurization, the on-off valve 11 is closed, then the on-off valve 10 is opened, and the vacuum is reduced again from the pressurized state at once.
In this embodiment, in a high-temperature state after consumption of zinc in the ceramic vaporization chamber 2 (for example, 907 to 950 ° C. is preferable, and 950 to 1000 ° C. is more preferable), vacuum reduced pressure (reduced pressure: preferably 100 Pa or less) Next, a purge gas supply consisting of purge opening, purge blowing and pressurization (pressurizing pressure: preferably 0.2 MPa) and exhaust opening are repeated a plurality of times as one cycle. By performing the above vacuum depressurization and purge gas supply multiple times in a high temperature state, the residual zinc that expands the minute holes in the furnace is efficiently removed and almost no minute holes on the ceramic surface, and the heating furnace is cooled and reheated. No cracks.

  In the present embodiment, the cooling trap 12 is installed in the exhaust pipe 6. Residual metal removed from the ceramic vaporizing chamber 2 by vacuum depressurization is trapped by the cooling trap 12, and the trapped metal is appropriately recovered. Since the trap is installed in the middle of the piping, the metal does not flow downstream from the trap, and the metal can be easily recovered. The recovered metal is reused after removing impurities and the like.

  In the cycle purge method according to the present invention, the ceramic composition of the ceramic vaporizing chamber 2 is not particularly limited, and alumina or the like can be used.

  In the cycle purge method according to the present invention, the metal to be heat-treated is not particularly limited, but any metal that can be vaporized at 1200 ° C. or less is applicable, and is optimal for zinc.

  In the cycle purge method according to the present invention, the heating furnace 1 is not particularly limited as long as the temperature in the vaporization chamber can be adjusted to 600 to 1000 ° C. As the heating furnace 1, for example, an electric furnace, a gas furnace, a heavy oil furnace, or the like can be used.

  Although it does not specifically limit as the gas gas consumption apparatus 3, For example, the reaction furnace etc. for making silicon tetrachloride gas and zinc gas react and forming silicon are mentioned. When the gas gas consuming apparatus 3 is the reaction furnace, the zinc gas generated in the heating furnace 1 is sent into the reaction furnace, and in the reaction furnace, the zinc gas is sent to the reaction furnace as well as the zinc gas. Silicon can be formed by reacting with silicon gas.

It is an example of an embodiment for enforcing the cycle purge method of the vaporization chamber for metal vaporization concerning the present invention, and is a schematic structure figure of the vaporization chamber for metal vaporization installed in the heating furnace.

Explanation of symbols

1. Heating furnace Ceramic vaporization chamber 2. 3. Gas consumption device Delivery pipe 5. Vacuum pump 6. 6. Exhaust piping Purge gas supply unit 8. Supply piping 9. On-off valve 10. On-off valve 11. On-off valve 12. Cooling trap 13. Zinc 14. Ceramic boat 15. Heat source

Claims (2)

A cycle purge method for a vaporization chamber for metal vaporization installed in a heating furnace,
The vaporization chamber is formed of ceramics;
Finishing the process of vaporizing the metal in the vaporizing chamber by heating and sending the generated vaporized metal to the vaporized gas consuming device through a delivery pipe connected to the vaporized chamber and connecting the vaporized chamber and the vaporized gas consuming device. Until the furnace is shut down,
Shutting off the vaporization chamber from a supply pipe connected to the vaporization chamber and supplying the purge gas to the vaporization chamber and the delivery pipe;
A pressure reducing and purging gas supplying step for supplying a purge gas to the vaporizing chamber through the supply pipe after vacuuming the vaporizing chamber through a discharge pipe connected to the vaporizing chamber and connecting the vaporizing chamber and the pressure reducing device in this order. ,
A cycle purge method for a vaporizing chamber for metal vaporization, wherein the pressure reduction and purge gas supply steps are continuously repeated a plurality of times.   The cycle purge method for a vaporizing chamber for metal vaporization according to claim 1, wherein a cooling trap is disposed in the middle of the exhaust pipe.

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