JP2604094B2 - Degreasing and calcination method for ceramic molded body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to, for example, sodium-
The present invention relates to a method for degreasing and calcining a ceramic molded body such as a beta alumina tube used as a solid electrolyte tube of a sulfur battery.

[0002]

2. Description of the Related Art Conventionally, a beta-alumina tube is prepared by first blending an organic binder or the like as a molding aid with a beta-alumina powder and press-molding it into a predetermined bottomed cylindrical shape by a molding machine. Thereafter, the beta-alumina compact is heated in a heating furnace, and degreased and calcined, that is, preliminary calcination is performed, and then main calcination is performed. Further, the end of the beta alumina tube is cut to obtain a desired beta alumina tube.

[0003] In the degreasing step, the beta-alumina molded body is heated to about 600 ° C at a predetermined heating rate in a heating furnace.

[0004]

However, the above-mentioned method which has been conventionally performed by the present inventor, when the product is deteriorated,
There was a problem . Further, the purpose is to perform degreasing, and the degreasing temperature has been performed at 600 ° C. or lower. For this reason, the molded body strength after degreasing was low, and it was sometimes damaged during handling.

[0005] Further, since the degreasing step is performed without introducing air, the evaporated portion of the binder and the decomposition gas partially stay in the heating furnace, the temperature distribution in the heating furnace becomes uneven, and Decomposition and combustion of the binder were insufficient due to lack of oxygen, and the binder component remained, resulting in a decrease in the density of the sintered body after sintering and poor dimensional characteristics. In addition, the compact is protected in the heating furnace.
Susceptible to uneven temperature distribution
There was a problem.

[0006] The present invention was made in view of the above-described conventional problems, and its object is deteriorated and damage prevention of the molded body, more smoothly and reliably degreased molded body in a degreasing step, the quality of the sintered body with stabilizing, the growth form
Beta aluminum that can prevent cracks from occurring
An object of the present invention is to provide a method for degreasing and calcining a molded body.

[0007]

To achieve the above object, according to the solution to ## beta alumina compact in the first invention in a pressurized hot furnace
A method of degreasing and calcining, wherein at least the degreasing temperature
Air pre-humidified at 200-600 ° C is introduced into the heating furnace.
It is characterized by entering . In the second invention, the dehumidification
Air is characterized in der Rukoto humidity of 20% or less. In the third invention, the beta-alumina compact is placed in a storage container.
And features that you have installed.

In a fourth aspect, the container according to the third aspect is provided.
Is set alternately with the setter and the sheath tube, above the top sheath tube.
Lid characterized that you have been configured as a set of those placed on the part. According to a fifth aspect of the present invention, there is provided a setter on which a sheath on which a beta-alumina molded body is provided in the fourth aspect of the invention is placed.
-There is a gap between them and the lower setter supports it
There is a gap between the trolley and the air that is introduced into the heating furnace.
At least part of the air introduced from the mouth is a trolley and a setter
Through the gap between the setters, through the gap between the setters,
Characterized that you discharged from the outlet of the heat furnace top.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention , a wind direction adjusting plate is disposed in an inclined state so as to face the air inlet in the heating furnace. It is characterized in that air is blown from a mouth to regulate the flow of air in the heating furnace . In the seventh invention, the device is installed in the storage container.
The placed beta alumina compact is degreased and temporarily
A method of baking, where beta degreasing and calcination are completed.
When retrieving Mina from container, the temperature of the storage vessel,
And wherein the retrieving at 1 40 ° C. or lower.

[0010]

According to the first aspect of the present invention, since the dehumidified air is forcibly introduced into the heating furnace in the degreasing step, the air in the heating furnace is stirred and the temperature distribution becomes substantially uniform. Will be retained. For this reason, the decomposition and combustion of the binder in the beta-alumina compact are performed uniformly and easily, and the supply of oxygen is carried out smoothly, so that the compact is inferior.
Is prevented.

In the second invention, the humidity of the dehumidified air is
Since it is 20% or less , the above-mentioned effects are further improved.
You. In the third invention, the beta-alumina molded body is a storage container.
It is evenly heated in a protected state . In the fourth invention, the storage container has a setter and a sheath tube alternately stacked, and
One with a lid placed on top of the upper sheath tube
From Rukoto consists beta alumina compact is housed
Heat treatment is performed uniformly in a protected state in the container .

In the fifth invention, the gap between the cart and the setter is provided.
Meanwhile, air is supplied to the gap between the setter and the sheath tube,
The temperature around the outer circumference of the sheath tube is made uniform and the beta alumina
Is more evenly heat-treated while protected inside the sheath tube.
You. Also, high-temperature exhaust gas is discharged from the upper part of the heating furnace
Therefore , dew condensation of water and adhesion of tar content are prevented. Sixth
According to the invention, the air introduced from the air introduction port hits a wind direction adjustment plate arranged in an inclined state so as to face the air introduction port, the flow direction thereof is adjusted, and the temperature distribution in the heating furnace is made uniform. You. In the seventh invention, degreasing and calcination are completed.
The beta-alumina molded body that has passed
By taking out at a temperature of 0 ° C. or less, the occurrence of cracks in the molded body is prevented.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG.
Is formed in a square box shape by a heating furnace main body 2 having an inverted L-shaped cross section, a truck 3 at the bottom, and an opening / closing door 4 at the front. The cart 3 has wheels 5 and is formed to be movable. A plurality of plate-like setters 6 made of alumina and a sheath tube 8 as a storage container are alternately stacked. The lowermost setter 6 is supported on the trolley 3 by support legs 7, and the upper end of the uppermost sheath tube 8 is covered with a lid 9. The sheath tube 8 is made of alumina. A plurality of beta-alumina compacts P are placed on the setter 6 in the sheath tube 8.

A certain gap is formed between the setter 6 and the carriage 3, and this gap is desirably at least 20 mm in order to allow air to pass therethrough and further make the temperature inside the heating furnace 1 uniform, and is preferably about 40 mm. Is optimal. Further, in order to make the ratio of the product including the sheath tube 8 to 50% or more of the effective volume in the heating furnace 1, the kiln filling method was a two-tiered stacking method.

The air introduction device 10 is disposed behind the heating furnace 1, and has a blower fan 11, a dehumidifier 12, and a filter 13.
, And are connected by a connection pipe 14. The connection pipe 15 connects the blower fan 11 to the inside of the heating furnace 1, and introduces dust and dehumidified air (outside air) from the blower fan 11 into the heating furnace 1 through the air inlet 17.

The wind direction adjusting plate 16 is provided obliquely at a lower portion of the outer side of the sheath tube 8 so as to face the air inlet 17 so as to face the air inlet 17. As shown in FIG. 2, the wind direction adjusting plate 16 has a notch 18
have. The air introduced from the air inlet 17 hits the wind direction adjusting plate 16 and most of the air flows upward, and a part of the air is introduced from the cutout portion 18 of the wind direction adjusting plate 16 below the setter 6.

Exhaust ports 20 are provided at three places in the upper part of the heating furnace 1. An exhaust duct 19 is connected to these exhaust ports 20, and air in the heating furnace 1 is exhausted from the exhaust ports 20 through the exhaust duct 19. The dampers 21 are attached to the respective exhaust ducts 19 and allow or block the exhaust of the air in the heating furnace 1. In addition, the thermocouple 22 for temperature measurement is arrange | positioned in the heating furnace 1,
The temperature in the heating furnace 1 is measured.

Next, the operation of this embodiment will be described. A large number of beta-alumina compacts P formed into a cylindrical shape with a bottom in accordance with a conventional method are placed in a sheath tube 8 in two upper and lower stages. Is done. Then, the door 4 is closed.

In this state, the process proceeds to a degreasing step for degreasing the beta alumina compact P. In the degreasing step, the binder in the beta-alumina molded body P is decomposed, burned and removed to prevent deformation of the molded body during firing. That is, the heating furnace 1 is heated by an electric heating device (not shown).
The inside is heated and heated, and degreasing is performed in the range of 200 to 600 ° C. At this time, the beta alumina molded body P in the sheath tube 8
The binder inside decomposes and burns by heating to generate gas, which is generated by the sheath tube 8, the setter 6 and the lid 9.
Flows out into the heating furnace 1 through the gap between them and the degreasing is promoted.

During this time, the air introduction device 10 is driven to introduce air from the air introduction port 17 into the heating furnace 1 to make the temperature distribution in the heating furnace 1 substantially uniform. It is desirable that the amount of air introduced during the degreasing is 1 to ³ m ³ / Hr. That is, the amount of air introduced per hour is equal to the volume of the heating furnace 1.
A range of 0.5 to 3 times is suitable, and a range of 1 to 2 times is optimal. Incidentally, in this embodiment, the size of the heating furnace 1 is 1150 mm in length, 600 mm in width, 900 mm in height and the volume is 0.6 m ^3.
It is.

The air thus introduced into the heating furnace 1 flows into the sheath tube 8 from the gap between the sheath tubes 8, and the oxidation of the binder is promoted. Then, generation of residual carbon in the beta alumina molded body P is prevented, and complete degreasing is performed. The introduction of air into the heating furnace 1 may be performed before the degreasing step, that is, before the temperature in the heating furnace 1 rises to 200 ° C. in order to make the temperature distribution in the heating furnace 1 uniform. Good.

The air introduced into the heating furnace 1 is heated to a high temperature, and is discharged from the exhaust port 20 and the exhaust duct 19 as exhaust gas together with the decomposition gas and the combustion gas of the binder. The exhaust port 20 and the exhaust duct 19 are provided in the upper part of the heating furnace 1, and since this part is in a high temperature state,
The moisture evaporated in the exhaust port 20 and the exhaust duct 19 is prevented from dew condensation and tar content in the binder is prevented from adhering. Therefore, the moisture absorption of the beta alumina molded body P can be reduced, and there is no possibility that the opening and closing of the damper 21 provided in the exhaust duct 19 will be hindered.
The introduced air is dehumidified to a humidity of 20% or less by the dehumidifier 12 while the dust is removed by the filter 13.
Deterioration of the molded body P is prevented.

The air introduced from the air inlet 17 into the heating furnace 1 hits the wind direction adjusting plate 16. Since the wind direction adjusting plate 16 is inclined, it is guided almost upward, and A convection is generated in the air flow.
Therefore, the air in the heating furnace 1 is in a stirring state, and the decomposition gas and the combustion gas of the binder do not partially stay in the heating furnace. In addition, the temperature distribution is made uniform, and the temperature difference between the upper and lower positions in the heating furnace 1 is reduced. The temperature distribution in the heating furnace 1 is preferably within ± 10 ° C. In addition, oxygen is supplied to the entire inside of the heating furnace 1, and generation of residual carbon in the beta-alumina molded body P in each sheath tube 8 is prevented.

A part of the air introduced into the heating furnace 1 is introduced from the notch 18 of the wind direction adjusting plate 16 into a gap of about 40 mm between the carriage 3 and the lower setter 6. In this case, the temperature distribution can be made uniform. Therefore, it is possible to prevent the spalling of the support leg 7 and the sheath tube 8, that is, the occurrence of cracks due to the difference in expansion due to the temperature change.

Next, the process proceeds to a calcination step. This calcination process
In order to develop the strength required for machining and handling of the degreased beta-alumina molded body P, 600 to 10
It is performed by heating to 00 ° C. Also in this step, in order to make the temperature distribution in the heating furnace 1 uniform, it is preferable to introduce air into the heating furnace 1 as described above.

Next, the cooling process is performed by
The temperature distribution in the heating furnace at the time of cooling is made uniform to prevent cracking of the molded body P, and the cooling is rapidly performed to improve the productivity of the product. That is, the air introduction device 10 is driven, and the heating furnace 1 is
Introduce cooling air into the interior. The amount of the cooling air introduced is preferably in the range of 15 to 20 m ³ / Hr, which is considerably larger than in the degreasing step, in order to maintain the cooling rate in a predetermined range. The cooling air introduced in this process also removes dust by the filter 13,
The humidity is reduced to 20% or less by the dehumidifier 12 to prevent the molded product P from deteriorating.

Thereafter, the temperature in the heating furnace 1 corresponding to the case where the temperature in the sheath tube 8 gradually decreases and reaches 140 ° C.
For example, when the temperature drops to 120 ° C., the heating of the electric furnace is stopped and the introduction of air is stopped at the same time. Then, after the opening and closing door 4 is slightly opened and the state is maintained for several minutes, the molded body P is gradually pulled out from the heating furnace 1. Under such conditions, even if the beta-alumina compact P is taken out of the heating furnace 1 immediately thereafter, there is no possibility that the compact P will crack. Therefore, the cooling time can be reduced, and the productivity is improved.

When the compact P is taken out in a state where the temperature inside the sheath tube 8 exceeds 140 ° C., the outer surface of the compact P is exposed to room temperature, and the temperature difference between the inside and the outside of the compact P is 100 °. ° C
As described above, the shape of the molded body P is thick at the bottom,
Since the side wall is thin, distortion occurs in the molded body P and cracks are likely to occur.

When the temperature inside the sheath tube 8 becomes 50 to 80 ° C. after leaving for 5 to 10 minutes, the lid 9 of the sheath tube 8 is removed,
The beta-alumina pipe molded body P is taken out, quickly put in a plastic bag, and sealed. In this way, a desired beta-alumina tube which has been calcined is obtained. If the temperature in the sheath tube 8 is lower than 50 ° C., the beta-alumina molded body P tends to absorb moisture, and if it exceeds 80 ° C., it becomes difficult for an operator to handle.

As described above, in this embodiment, since the inner volume of the heating furnace 1 is effectively used, degreasing and calcination can be performed efficiently and economically, and the cost of the product can be reduced. Can be. In addition, since the temperature distribution in the heating furnace 1 in the degreasing step can be significantly improved, the beta-alumina molded body P can be smoothly and reliably degreasing. In addition, since the temperature distribution can be improved by introducing air into the heating furnace 1 also in the cooling process, it is possible to reliably prevent cracks from being generated in the compact P, and
The cooling process can be performed quickly.

The present invention is not limited to the above embodiment, but may be embodied by arbitrarily changing the configuration as follows without departing from the spirit of the invention. (A) An air inlet 17 for forcibly introducing air into the heating furnace 1 is provided in the upper part of the heating furnace 1 and the exhaust duct 1
9 is provided in the lower part of the heating furnace 1 to drive the air introducing device 10 in the cooling process. In this case, the cooling air is introduced from the high temperature part and the exhaust gas is exhausted from the low temperature part, so that the cooling efficiency is improved. Further, the temperature distribution in the heating furnace 1 is also made uniform. (B) In the above embodiment, the heating furnace 1 is a single vessel.
A tunnel kiln-shaped container that can continuously operate the degreasing, calcining, and cooling steps. (C) A plurality of air introduction ports 17 of the air introduction device 10 are provided in the heating furnace 1, and air is introduced into the heating furnace 1 from the plurality of places. In this case, the air introduction device 10 may be provided corresponding to each air introduction port 17. (D) For example, a stirring fan for adjusting the flow of air in the heating furnace 1 is provided at the upper part . (E ) Instead of a heating furnace using an electric furnace, an indirect heating furnace using a radiant burner is used. ( F ) Introducing heated air during the degreasing process. ( G ) Introducing a cooling gas other than air during the cooling process.

[0032]

Since the present invention is configured as described above in detail, it has the following excellent effects.

According to the first invention, since that is configured to introduce a degreasing Engineering as was moistened forcibly advance divided into Oite heating furnace in the air, the temperature distribution in the heating furnace in the degreasing process Improves the decomposition of binders in beta alumina compacts
And combustion are performed uniformly and easily, and oxygen is supplied.
Is performed smoothly, the beta-alumina compact can be degreased smoothly and reliably, and the quality of the sintered compact can be stabilized.
Door is Ru can.

According to the second invention, the humidity of the dehumidified air is
Since the degree is 20% or less, the effect of the first invention is further enhanced.
You improve. According to the third or fourth aspect of the present invention, the beta-alumina molded body is uniformly protected while being protected in the storage container or the sheath tube.
Ru can be heated.

According to the fifth aspect of the present invention, the carriage and the setter are
Air is supplied to the gap, the gap between the setter and the sheath tube
The temperature around the outer periphery of the sheath tube is made uniform,
Heat treatment more uniformly with the shape protected in the sheath tube
Can be In addition, the high temperature exhaust gas
Discharge prevents moisture condensation and tar adhesion
can do. In a sixth aspect, the effects of the fifth aspect are provided.
In addition, the air introduced from the air inlet is
Contact the wind direction adjustment plate
Therefore, the flow direction is adjusted, and the temperature
Ru can be made uniform cloth. In the seventh invention, the degreasing
After the calcined beta alumina compact,
By removing at a temperature of 140 ° C or less,
Ru it is possible to prevent the occurrence of cracking.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an apparatus for degreasing and calcining according to an embodiment of the present invention.

FIG. 2 is a front view showing a wind direction adjusting plate.

[Explanation of symbols]

1 ... furnace, 6 ... setter, 8 ... sheath tube as container, 16 ... wind direction adjusting plate, 17 ... air introducing port, P ... base Taarumina moldings.

Claims (7)

(57) [Claims] 1. A degreasing beta-alumina formed body with a pressurized hot furnace
And calcining, wherein at least the degreasing temperature is 20.
Introduce air previously dehumidified at 0-600 ° C into the heating furnace
Degreasing and calcination method beta alumina compact, characterized in that that. 2. The method according to claim 1, wherein the dehumidified air has a humidity of 20% or less.
Degreasing and calcination method beta alumina <br/> molded body according to claim 1, characterized in Rukoto Oh. 3. The method according to claim 1, wherein the beta-alumina molded body is in a storage container.
Base according to claim 1, characterized that you have installed in
Method for degreasing and calcining the alumina molded body. 4. The container has a setter and a sheath tube alternately.
Laminated, with lid placed on top of top sheath tube
The claim 3, characterized that you have been configured as a set
3. The method for degreasing and calcining a beta-alumina molded article according to item 1. 5. A setter on which a beta-alumina molded body is installed.
-There is a gap between the sheath tube and the bottom setter
There is a gap between the
At least part of the air introduced from the air inlet into the
Pass through the gap between the car and the setter,
The method for degreasing and calcining a beta-alumina molded product according to claim 4 , wherein the beta-alumina molded product is discharged through an exhaust port at an upper portion of the heating furnace through the gap . 6. An air inlet in the heating furnace.
The wind direction adjustment plate is installed in an inclined state so that
Air is blown from the air inlet to
Degreasing and calcination method beta alumina molded article according to claim 5, characterized that you adjust the flow of air. 7. A beta alumina installed in a storage container.
A method for degreasing and calcining a molded body in a heating furnace,
Remove beta-alumina from the storage container
When taking out, take out at a temperature of 140 ° C or less in the storage container
Degreasing and calcination method beta alumina compact, characterized in that to.