JPH0218400A - Device for producing si-based whisker - Google Patents

Abstract

PURPOSE:To continuously produce the title whiskers of Si3N4, SiC, etc., with a high recovery rate by using a device of specified structure. CONSTITUTION:A reaction cylinder 1 in which contains a perforated member 4 for receiving a solid raw material A (e.g., chaff charcoal) and a cylinder 2 for forming whiskers are set in a heating furnace 10. The cylinders 1 and 2 are connected with a communicating pipe 3 to introduce vaporized SiO into the cylinder 2 through the pipe 3. A raw material feeder 20 and a gas supply pipe 24 for introducing gaseous reactants (e.g., N2, NH3, and CH4) and a carrier gas (e.g., H2) are provided to the reaction cylinder 1, a gas supply pipe 25 for introducing gaseous reactants and a catalytic gas (e.g., iron carbonyl) is furnished below the perforated member 4, and a whisker scraping and extruding device 30 is provided to the cylinder 2. The gaseous reactants are selected in accordance with the desired whiskers, introduced into the reaction cylinder 1 from the respective gas supply pipes 24 and 25, and then introduced into the cylinder 2 along with the SiO vaporized from the raw material A to form whiskers B. The whiskers are pushed up by the scraping and extruding device 30, stored as a wiry body C, and then discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to silicon nitride (Si3N4) whisker silicon carbide (
The present invention relates to an apparatus for producing Si-based whiskers such as SiC whiskers.

[Conventional technology]

Si-based whiskers are synthesized by reacting raw material silicon monoxide (Si0) with a reactive gas such as methane (CH, ), nitrogen (N2), or ammonia gas (NH3). The manufacturing equipment for this Si-based whisker is as follows:
For example, JP-A-61-14200 and JP-A-47-
There is one disclosed in Japanese Patent No. 18531.

In the former, a carbon reaction tube is connected to the top of the raw material filling container,
Silicon monoxide (S i O) from a raw material is fed into the reaction tube together with a reaction gas, and whiskers are grown on the inner peripheral surface of the reaction tube. In addition, in the latter case, a raw material filling container, a heating electrode, and a reaction member for whisker growth are arranged in a heating furnace lined with a heat insulating material, and silicon monoxide (SiO) from the raw material and a reaction gas supplied to the furnace are and to grow whiskers on the surface of the reaction member.

(Problems to be Solved by the Invention) However, in whisker production using these conventional production devices, a predetermined amount of raw material is filled into a container, and when whisker production using this raw material is completed, the device is temporarily stopped.
Since it is a batch operation in which generated whiskers are taken out and new raw materials are filled into the container again, there is a problem of poor whisker production efficiency.

In addition, whiskers are generated on the inner wall surface of the filling container portion in the former case, and whiskers are generated on the inner wall surface of the furnace in the latter case, resulting in a reduction in recovery efficiency.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a Si-based whisker manufacturing apparatus that can produce whiskers continuously without the need to temporarily stop the apparatus midway through the production process, and that can collect the generated whiskers more efficiently than in conventional apparatuses. purpose.

[Means to solve the problem]

In accordance with the above-mentioned object, the present invention includes a reaction tube having a porous member for solid material receiving therein and a generation tube for generating whiskers, which are installed in a heating furnace, and the two tubes are connected in the heating furnace by a communicating tube. The silicon hydride is connected to allow raw material gas to flow into the production bay through the communication pipe, and the reaction tube is provided with a raw material supply device, and the production tube is provided with a whisker pushing device. The present invention provides an apparatus for manufacturing whiskers.

[Function] According to the whisker manufacturing apparatus of the present invention, the solid raw material that generates vaporized SiO by heating is supplied into the reaction column by the raw material supply device, and the solid raw material that generates vaporized SiO by heating is supplied into the reaction column, where S is heated and vaporized into a gaseous state.
iO is generated, and the SiO enters the generation cylinder through a communication pipe together with the gas supplied from the atmospheric gas supply section, where reactions such as nitriding and carbonization reactions occur to generate whiskers on the inner wall surface of the generation cylinder. do. The generated whiskers are scraped off from the inner wall surface of the generation cylinder by the whisker scraping device and pushed to the whisker extraction section, where they are extracted.

New raw materials are successively supplied into the reaction column by a raw material supply device in an amount commensurate with the decrease in the raw materials in the reaction column, and whiskers are continuously produced in the production column.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

The drawing shows a cross-section of one embodiment of the whisker manufacturing apparatus.

In the figure, 10 is a heating furnace, and the furnace IO is lined with a heat insulating material 11, and an electric heater 12 is provided inside.

Further, in this heating furnace 10, a vertical reaction tube 1 and a vertical generation tube 2 are installed in parallel. The upper and lower ends of both cylinders protrude outside of the heating furnace IO. The reaction tube 1 and the production tube 2 communicate with each other through a communication tube 3 at the bottom of the heating furnace 10.

The reaction tube 1 is provided with a porous member 4 made of a perforated plate or the like for receiving and stopping raw materials at a position slightly higher than the communication tube.

A cap 6A is attached to the upper end of the reaction tube l via a sealing material 5.
is removably provided, and a raw material supply device 20 is connected to this cap.

The raw material supply device 20 includes a cylindrical body 21 passing through the cap 6A and a raw material hopper 23 connected to this via a feeder having a sealing mechanism, such as a rotary pulp 22. The cylindrical body 21 extends into the heating furnace IO. An atmospheric gas supply pipe 24 is connected to this cylinder 21 .

The supply pipe 24 is branched, and one side is connected to the raw material supply device 2.
0 and the other to the cap 6A, and in this example, a carrier gas and a reaction gas are supplied from a gas supply source (not shown).

Further, a cap 7A is removably provided at the lower end of the reaction cylinder l, and an atmospheric gas supply pipe 25 is connected to the cap 7A.
It is installed by penetrating A and being inserted into the cylinder l.1. The gas outlet 25A faces the inlet of the communication pipe 3. A reaction gas and a catalyst gas are supplied to this gas supply pipe 25 from a gas source (not shown) in this example.

An openable/closable door 8 for removing whiskers is provided at the upper end of the generation cylinder 2, and an exhaust pipe 9 is provided.

A whisker scraping device 30 is provided at the lower end of the generating cylinder 2.

The device 30 consists of a scraping piston 31 that slides up and down within the production cylinder 2, a rod 32 connected to the piston, and a drive bag rt33 that drives the rod 32 back and forth. The rod 32 passes through a removable bottom cap 7B at the lower end of the tube 2. The drive device 33 is a chain 34
A part of the chain 34 is connected to the lower end of the rod 32, and is wound around two sprockets 35 and 36, and can be rotated back and forth by rotating one of the sprockets by a motor (not shown). The rod 32 and therefore the piston 31 move up and down.

According to the whisker manufacturing apparatus of this embodiment, a solid raw material A that generates vaporized SiO by heating is put into the hopper 23 of the raw material supply device 20, and the raw material is fed to the rotary valve 22.
2, it falls from the cylinder 21 into the perforated plate 4 inside the reaction cylinder 1 and is filled.

In this example, rice husk charcoal is used as the solid raw material.

The raw material A is supplied into the reaction cylinder 1 by successively opening the rotary pulp 22 in an amount corresponding to the amount reduced by the reaction.

The reaction tube 1 is normally heated to 1300-1400°C, and Sing contained in the rice husk smoky coal raw material A is reduced by the carbon contained in the raw material A, becoming SiO, and the S
iO is sent below the porous member 4 together with the reaction gas and carrier gas from the gas supply pipe 24, and together with the catalyst gas and reaction gas sent from the gas supply pipe 25 provided in the bottom space of the reaction tube l. It passes through the communication pipe 3 and enters the production cylinder 2.

These gases usually undergo nitriding reactions, carbonization reactions, etc. in the production cylinder 2 heated to 1350 to 1450°C, and generate whiskers B on the inner wall surface of the production cylinder 2.

When enough whiskers B have been generated, the scraping device 3
The piston 31 of No. 0 is raised and pushed upward while scraping off the whiskers B, and is stored as flocculent whiskers C in the space of the cap 6B.

Excess and/or unnecessary gas is discharged to the outside through the exhaust pipe 9.

When enough whiskers have accumulated in the space of the cap 6B, the door 8 is opened and the cap 6B is taken out.

In the embodiment described above, when obtaining silicon nitride whiskers, the reaction gas such as Nt or NH is supplied from the gas supply pipe 24 and the carrier gas is, for example, Hz, and the reaction gas is supplied from the gas supply pipe 25 such as Nt or NH. Alternatively, iron carbonyl may be supplied as a catalyst gas.

In addition, when obtaining silicon carbide whiskers, from the gas supply pipe 24, for example, CHs is supplied as a reactive gas, and for example, H2 is supplied as a carrier gas, and from the gas supply pipe 25, for example, CHa is supplied as a reactive gas, and iron is supplied as a catalyst gas. Just supply carbonyl.

In addition to the above-mentioned rice husk smoked charcoal, the solid raw materials include
, and a flake-like mixture consisting of carbon powder.

According to the embodiment described above, there are the following advantages.

- Since the reaction tube 1 for reaction vaporization of the solid raw material A and the whisker generation tube 2 are separated, the raw material can be supplied into the reaction tube 1 in accordance with the amount of reduction reaction of the raw material.
This improves the operating efficiency of the equipment and enables automation. In the above embodiment, since the reaction column 1 is vertical, it is particularly convenient for supplying raw materials.

(2) Almost all of the whiskers B generated on the inner wall surface of the generation cylinder 2 can be taken out without stopping the apparatus, and the operating efficiency of the apparatus can be increased accordingly, as well as the whisker recovery efficiency.

■ The cylinders 1 and 2 are vertical, and the caps 6A and 6
B.? The fact that A and 7B are removable also makes it easy to clean the reaction tower and production group, such as processing residual raw materials, making the maintenance of the apparatus that much easier.

(2) Since the atmosphere inside the reaction tube 1 flows from the upper part of the raw material to the lower part, the 5ill gas that has been reductively decomposed can be efficiently guided to the production group 2.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented in various other ways.

For example, the reaction cylinder and the production cylinder do not necessarily have to be vertical, and may be arranged horizontally, for example. In such a case, as a raw material supply device, for example, a raw material hopper is provided at one end of a screw conveyor inserted into the reaction cylinder, and the raw material in the hopper is transferred to the cylinder from time to time according to the decrease in the raw material in the reaction cylinder. It may also be supplied inside.

[Effects of the Invention] According to the present invention, Si-based whisker production is possible, in which whiskers can be produced continuously without the need to temporarily stop the device, and the recovery efficiency of generated whiskers can be made higher than in conventional devices. equipment can be provided.

[Brief explanation of the drawing]

The drawing is a cross-sectional view of one embodiment. 10... heating furnace, l...reaction tube, 2...Generation cylinder, 3...Communication pipe, 4... Porous member, 20...raw material supply device, 24.25...atmosphere gas supply pipe, 30... whisker scraping device, 8...Whisker removal door, A...solid raw material, B, C...whisker

Claims (1)

[Claims] (1) A reaction cylinder having a porous member for receiving solid raw material inside and a generation cylinder for generating whiskers are installed in a heating furnace,
In the heating furnace, the two cylinders are connected by a communication pipe so that vaporized SiO flows into the production cylinder through the communication pipe, and the reaction cylinder is provided with a raw material supply device, and the production cylinder is provided with a raw material supply device. 1. A Si-based whisker manufacturing device characterized by being equipped with a whisker pushing device.