JP2579760C - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a reactor for efficiently reacting a raw material powder or particles with a reaction gas. <Prior art> Nitride ceramics such as silicon nitride and aluminum nitride and silicon oxynitride,
Oxynitride ceramics such as aluminum oxynitride and sialon have excellent properties such as mechanical properties and thermal properties. For example, silicon nitride has excellent properties of heat resistance and thermal shock resistance, and is a material excellent not only in normal temperature strength but also in high temperature strength. It is expected as one of the materials that can realize high temperature, light weight, and high efficiency of heat engines such as turbines. Also,
Aluminum nitride has high thermal conductivity and excellent electrical properties such as insulation resistance, dielectric strength, dielectric constant and mechanical properties such as strength.
It is attracting attention as a package material. Since the characteristics of these nitride and oxynitride ceramics depend on the characteristics of the raw material powder, high-purity and uniform fine powder having excellent sinterability is required. Methods for synthesizing nitride and oxynitride powders include direct nitriding of metals, reductive nitriding of oxides, pyrolysis of organometallic compounds containing nitrogen such as imide, and gas phase reaction using chlorides. However, as a method for industrially obtaining an inexpensive high-quality fine powder, an oxide reductive nitridation method is excellent. In the reductive nitridation method of oxides, usually, saggers containing silicon oxide or mixed powder of alumina and carbon are stacked in multiple stages, and a nitriding reaction is carried out while flowing a reaction gas such as nitrogen. It is important how to efficiently and uniformly flow gas into each sagger and supply it to the reaction, and then to exhaust it smoothly, which is important for industrially obtaining high-quality nitride or oxynitride powder. Is the point. <Problems to be Solved by the Invention> In a conventional reactor, saggers provided with notches in diagonal directions or upper portions of side walls are stacked in multiple stages on a base plate, and a reaction gas is introduced from one side of the reactor. Then, a method called so-called shelf type that exhausts from the opposite side is taken. However, in such a method, most of the reaction gas introduced into the furnace flows around the multi-stage sagger, and only a part of the reaction gas introduced into the furnace flows into the sagger. In order to allow the reaction to proceed sufficiently, it was necessary to introduce a considerably larger amount of reaction gas than required. Also, it is difficult to uniformly flow a certain amount of reaction gas into each of the stacked saggers, and the quality of the reaction product often varies from one sagger to the other. An object of the present invention is to provide a reaction furnace in which saggers containing raw material powders or particles are stacked in multiple stages on a base plate to react the raw material powders or particles. An object of the present invention is to provide a reaction furnace in which the introduced reaction gas is evenly distributed to each of the stacked saggers without waste, and the reaction gas flows smoothly in each of the saggers. <Means for Solving the Problems> The present invention provides a reaction furnace in which saggers containing raw material powders or particles are stacked in multiple stages on a base plate and reacts the raw material powders or particles. And a notch or a hole for the first passage of the post-reaction gas is provided, and a partition having a notch is provided near the opposing side wall, and the reaction gas and the Using a sagger provided with a hole for the second passage of the post-reaction gas and a base plate provided with an inlet or an outlet for the passage of the reaction gas and the post-reaction gas,
The reaction gas introduced into the furnace from the inlet is discharged from the second passage via the first passage or discharged from the first passage via the second passage, and the raw material powder or particles are discharged. The present invention is to provide a reaction furnace characterized in that the reaction furnace passes through above, diffuses into raw material powder or particles, is subjected to a reaction, and is then exhausted from an exhaust port. The reaction furnace of the present invention is a reaction between a raw material powder or particles and a gas, particularly silicon nitride,
In the synthesis of nitride powders such as aluminum nitride and oxynitride powders such as silicon oxynitride, aluminum oxynitride, and sialon by oxide reduction nitridation, a reaction gas such as nitrogen gas is placed in a sagger containing raw material powder or particles. It is useful as a nitriding reactor for performing the above reaction. The reaction furnace of the present invention is a batch type, and it is possible to continuously perform a reaction by sequentially moving the inside of the furnace by guiding a large number of base plates on which the saggers are stacked in multiple stages like a pusher furnace to rails. Includes a possible reactor. Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1A shows the structure of a sagger used in the present invention, and FIG. 1B shows the structure of a base plate. The sagger 6 is usually made of a material such as graphite, silicon carbide, silicon nitride, and aluminum nitride. FIG. 2 is a sectional view when the sagger 6 is stacked on the base plate 7 in the batch furnace according to one embodiment of the present invention. In FIG. 2, 1 is a reaction gas inlet, 2 is a thermocouple for controlling temperature, 3 is a heater made of graphite, 4 is an inlet of a furnace for taking in and out of the sagger, and 5 is an outlet for gas after reaction. . Reference numeral 6 denotes a sagger containing raw material powder or particles, and reference numeral 7 denotes a base plate. The sagger 6 has a notch 8 at the upper part of the side wall of the sagger for the first passage of the reactant gas and the post-reaction gas, and a partition wall 9 having a notch near the opposite side wall 9 ".
And a hole 9 for a second passage for the reaction gas and the post-reaction gas at the bottom of the sagger on the opposite side wall. 10 raw powders or particles
After that, the holes 9, 9, ... provided at the bottom of the saggers 6, 6, ... are stacked in multiple stages so as to overlap each other. By being stacked in multiple stages, the holes 9, 9,... Provided at the bottom of each sagger are continuously connected to form a gas passage 12 for the post-reaction gas. The reaction gas introduced into the furnace from the inlet of 1 is introduced into each sagger from the cutout 8 provided at the upper part of the side wall of each sagger 6, 6,. After being diffused into the raw material powders or particles and subjected to the reaction, along with the by-product gas generated by the reaction, the gas was provided in the passage 12 and the base plate 7 where the holes 9, 9,. The gas is exhausted from the gas exhaust port 5 through the exhaust port 13 after the reaction of the reaction furnace. With such a structure, a fixed amount of fresh reaction gas is always supplied to each of the saggers 6, 6,..., And often by-product gas that hinders the progress of the reaction can be smoothly removed. The reaction proceeds efficiently and uniformly. In addition, since all the reaction gas is exhausted after passing through the inside of the sagger, the loss of the reaction gas is greatly reduced. FIG. 3 is a horizontal sectional view and a temperature distribution of a pusher furnace according to another embodiment of the present invention, and FIG. 4 is a vertical sectional view. The sagger and the base plate have substantially the same structure as those shown in FIGS. 1 (A) and 1 (B). In FIG. 3, 14 is an outer furnace body, 15 is a muffle housed in the outer furnace body 14,
Reference numeral 21 denotes an inlet for the reaction gas, and reference numeral 22 denotes an outlet for the gas after the reaction. An inlet 16 and an outlet 17 are provided on both sides of the outer furnace body 14 in the longitudinal direction. A rail 18 is laid on the bottom surface of the muffle 15 along the furnace length, and a base plate 7, 7,... Is mounted on the rail 18 so as to be movable from an inlet 16 to an outlet 17 of the furnace. On each of the base plates 7, 7,..., Saggers 6, 6,... Filled with the raw material powder or particles 11 are stacked so that the holes 9, 9,. This sagger 6
, 6, ... are stacked on the rail 18 from the furnace entrance 16 and push rods 19
, And inserted into the furnace, whereby each base plate 7,7, ... is placed in front of the base plate 7,7,
… Is extruded through the soaking zone 20 toward the outlet. By repeating this, the sagger 6,6,…
Are passed through the soaking zone 20 and sequentially subjected to the reaction, and then exit the furnace from the outlet 17. Although the basic structure of this pusher furnace is not different from the conventional pusher furnace at all, in the present invention, by using the sagger 6 and the base plate 7 as shown in FIG. The reaction gas introduced into the furnace passes through the saggers 6, 6, ... and is subjected to the reaction, and is then exhausted from the gas exhaust port 22 after the reaction.
There is almost no reaction gas exhausted without passing through... And efficiency is improved. In addition, the number and position of the reaction gas introduction ports can be appropriately provided by the reaction. In addition, the reaction gas inlet 22 (or 5) is used as a reaction gas inlet, and the reaction gas inlet is provided.
There is no problem if 21 (or 1) is used as a gas outlet after the reaction.
If the product is easy to volatilize or if a large amount of easily volatilizable by-product is generated, the inside of the furnace may be contaminated. Therefore, it is preferable to exhaust the gas from the bottom of the muffle. Further, as shown in FIG. 5, a partition 24 may be provided at an appropriate position in the exhaust zone 23 at the bottom of the muffle to allow the reaction gas to flow as indicated by arrows 25,... In FIG. When the raw material contains water or contains a substance that evaporates at a low temperature, as shown in FIG. 5, the reaction gas is introduced from the bottom of the muffle in the cooling section, and the sagger 6,6 , ..., heat exchange to heat the reaction gas, and then introduce it into the saggers 6,6, ... in the soaking section, conduct the reaction, exhaust it, and partially remove the sagger in the heating section. 6,6,
Is desirably introduced into the... To remove water and evaporative substances and exhausted from the exhaust port 26 of the post-reaction gas. In this case, a flow control valve 27 is always provided at the exhaust port 26. <Effect of the Invention> The reaction furnace according to the present invention makes the supply of the reaction gas to each sagger containing the raw material powder or particles uniform, and minimizes the amount of the reaction gas exhausted without participating in the reaction. It is possible to reduce the amount and efficiently obtain a high-quality reaction product without variation. In addition, by using the reactor according to the present invention, the production of nitrides and oxynitrides such as silicon nitride, aluminum nitride, silicon oxynitride, aluminum oxynitride, and sialon by the reductive nitridation method of oxides is performed more efficiently. I can do it. Further, a similar structure can be applied to various oxidation furnaces and sintering furnaces.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an example of a sagger and a base plate used in a reactor according to the present invention, FIG. 2 is a cross-sectional view of a batch furnace according to an embodiment of the present invention, FIG. Is a cross-sectional view in a horizontal direction of a pusher furnace as another embodiment of the present invention, FIG. 4 is a vertical cross-sectional view of the same, and FIG. 5 is a cross-sectional view in a horizontal direction of a pusher furnace as another embodiment. . DESCRIPTION OF SYMBOLS 1 ... Reaction gas inlet, 2 ... Thermocouple for temperature control, 3 ... Heater, 4 ... Furnace inlet, 5 ... Gas outlet after reaction, 6 ... Sagger, 7 ... Base plate, 8 ... Side wall of sagger Notch of 9 ...
Hole at bottom of sagger, 9 '... partition with cutout, 9 "... side wall of sagger, 10 ... filling material powder of sagger, 11 ... material powder, 12 ... gas passage, 13 ... exhaust port, 14 ... Outer furnace body, 15 muffle, 16 inlet, 17 outlet, 18 rail, 19 push rod, 20 soaking zone, 21 reactant gas inlet, 22 gas outlet after reaction, 23 bottom of muffle Exhaust zone, 24 ... Partition, 25 ... Arrow indicating the flow of reaction gas, 26 ... Exhaust port for gas after reaction, 27 ... Flow control valve

Claims (1)

Claims: (1) In a reaction furnace in which saggers containing raw material powders or particles are stacked in multiple stages on a base plate to react the raw material powders or particles, a reaction gas and a post-reaction gas are provided on one side wall upper part. A notch or a hole for the first passage is provided, a partition having a notch is provided near the opposing side wall, and the reaction gas and the post-reaction gas are provided at the bottom of the opposing side wall glue sagger. The sagger provided with a hole for the second passage, and a base plate provided with an inlet or outlet for the passage of the reaction gas and the post-reaction gas, and the reaction introduced into the furnace from the inlet was used. Gas is discharged from the second passage via the first passage or from the first passage via the second passage and passes over the raw material powder or particles and the gas within the raw material powder or particles. After being diffused to the A reactor that is exhausted from a vent.