JP2009227501A - Heating method using sagger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a firing method using a sagger by which a material to be heated housed in the sagger is evenly fired by suppressing the unevenness of the temperature distribution of the inside of the sagger while excellently keeping the contact of the exhaust of a produced gas or a reaction gas with the material to be heated. <P>SOLUTION: The material to be heated such as powder is charged to the sagger 1 having an aeration part 9 on a part or the whole of the bottom surface and fired. A produced gas produced from the material to be heated is discharged from a furnace bottom part by bringing suction holes 10, 11 formed on the sagger supporting surface into close contact with the bottom surface of the sagger 11 to suck the inside of the sagger 1 while supplying a fresh gas into a furnace in a temperature rising zone. The fresh gas flows in the vicinity of the material to be heated in the sagger 1. The diffusion of an inverter gas to the furnace is eliminated and the temperature distribution is also made uniform. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heating method using a mortar used for firing ceramic powder or the like as a raw material for the electronics industry.

  When firing ceramic powders that are used as raw materials for electronic industrial products such as ceramic capacitors, lithium-ion batteries, and phosphors, the powders are stored in a kiln tool called a sagger. It is normal. Industrially, continuous baking is performed in which a mortar is sequentially placed in one end of a continuous furnace in which a predetermined firing temperature curve is formed, fired while moving in the furnace, and taken out from the other end.

From these powder materials, various gases are generated in the temperature rising region before reaching the firing temperature. Mainly, CO ₂ is used for ceramic capacitors, alkaline gas or metal lithium evaporating gas is used for lithium ion batteries, and SO _X and HCL are used for phosphors. In such a powder firing method, the temperature distribution of the powder is made uniform, the generated gas is quickly exhausted, and the reaction gas supplied from the outside is made uniform with the powder. Contact is important.

  However, since the powder is usually only stored inside the mortar, the portion close to the surface of the mortar is easily heated, but the central portion is not easily heated, and uneven temperature distribution tends to occur. Further, since the ventilation is only natural ventilation, the exhaust of the generated gas and the contact between the reaction gas and the powder proceeded slowly, leading to longer firing and deterioration of firing characteristics. Therefore, the following solutions were sought.

  That is, Patent Document 1 discloses a technique for suspending a suction tube for atmospheric gas in a furnace in a temperature rising region at a constant interval so as to suck generated gas quickly and exhaust the atmospheric gas from the furnace floor. Is disclosed. However, when powder is baked using this technique, the ventilation flow only flows through the surface layer of the sagger and does not reach the center of the sagger. The generated gas diffuses into the furnace and causes the furnace atmosphere to become polluted. For this reason, only the technique of this patent document 1 is not suitable for good firing of the powder.

  Patent Document 2 discloses a method of making the temperature distribution of a powder having poor heat conduction uniform by standing a heat conductor inside the mortar and firing the powder. However, there are problems such as a reduction in the amount of powder in the mortar, a difficulty in supporting the heat conductor, and the heat conductor interfering when the powder is taken in and out. Moreover, the exhaust of the generated gas or the contact between the reaction gas and the powder is not improved.

Further, in Patent Document 3, the mortar is made of a porous material composed of ceramic particles having a plurality of particle size distributions so that the generated gas generated from the powder can be easily diffused. If such a mortar is used, air permeability is improved as compared with a normal mortar. However, the airflow is not actively going in and out, and the gas movement inside the bowl is only natural ventilation.
Japanese Patent No. 2522877 JP 2000-226266 A JP-A-8-268774

  Accordingly, an object of the present invention is to suppress nonuniform temperature distribution in the interior of the sagger with respect to the powder and other objects to be heated contained in the sagger, and also to exhaust the generated gas and the reaction gas and the object to be heated. It is to provide a heating method using a sagger that can be uniformly heated while maintaining good contact.

  The present invention made in order to solve the above problems is a heating method in which an object to be heated contained in a sagger is heated while moving in a heating furnace. Means for generating a differential pressure from the outside of the furnace with respect to the vent hole formed on the support surface of the sagger, with the vent hole formed on the support surface of the sagger in close contact with The pressure difference is applied by the above, and the inside of the mortar is sucked or scavenged.

  As in claim 2, the inside of the sagger can be sucked in the temperature range where gas is generated from the object to be heated, and in the maximum temperature range, the inside of the sagger can be scavenged in the maximum temperature range. it can. These may be performed alone or both at the same time. Use of the mortar according to claim 1 or 2

  Further, as in claim 4, the heating furnace is a plate type pusher furnace that moves the mortar on the base plate and moves the inside of the mortar through suction holes formed in the base plate and the hearth that supports the base plate. Or the firing furnace is a walking beam furnace in which the sagger is moved by a moving beam, and the interior of the sagger is passed through suction holes formed in the fixed floor. An embodiment of aspiration can also be taken. In the present invention, it is preferable that the breathable material on the bottom surface of the mortar is a porous material.

  According to the heating method using the mortar of the present invention, using the mortar having a part or the whole of the bottom made of a breathable material, while supplying fresh gas into the furnace in the temperature rising range, The suction holes formed in the pot support surface are brought into close contact with the bottom surface of the pot, the inside of the pot is sucked, and firing is performed while the gas generated from the object to be heated is discharged from the bottom of the furnace. For this reason, the gas passes through the vicinity of the object to be heated inside the sagger and positive ventilation is performed, so that the effect of discharging the generated gas is enhanced and the generated gas can be prevented from diffusing into the furnace. As a result, there is no contamination of the furnace atmosphere, no contamination of the furnace inner wall, no leakage of the generated gas from the furnace inlet, and no generated gas flows into the firing zone.

  In addition, since the fresh gas supplied into the furnace passes through the vicinity of the object to be heated in the sagger, the reaction between the object to be heated and the gas can be performed quickly, and the firing rate can be improved. Reacts efficiently with the object to be heated, so that the amount of gas used can be reduced. Furthermore, unlike the prior art in which heating by heat conduction through the mortar is performed by the gas flowing inside the mortar, the temperature distribution of the object to be heated inside the mortar can be made uniform, It is possible to shorten the firing time and improve the firing quality.

  If the breathable material on the bottom surface of the sagger is a porous material as in claim 6, the material to be heated will not flow out even if it is a powder, and it will face down from the furnace chamber ceiling in the temperature rising region. If a fresh gas is supplied to the furnace, a downward flow is formed in the furnace chamber, and the generated gas can be more reliably prevented from diffusing into the furnace.

Hereinafter, preferred embodiments of the present invention will be described.
1 to 3 are views showing an embodiment in which the present invention is applied to a base plate type pusher furnace. 1 is a cross-sectional view in the furnace width direction in the temperature rising region, FIG. 2 is a cross-sectional view in the furnace length direction in the temperature rising region, and FIG.

  The base plate type pusher furnace is a furnace of a type in which the mortar 1 is placed on the base plate 2 and pushed from the furnace inlet side with a pusher to move in the furnace. 1 and 2, 3 is a furnace body, and 4 is a hearth that is a mortar support surface. Guides 5 for restricting the traveling direction of the base plate 2 are provided on both the left and right sides of the hearth 4. Inside the furnace chamber 6, heaters 7 and 8 are respectively arranged above and below the hearth 4 and a predetermined temperature curve is formed in the longitudinal direction of the furnace. It is the same as before that the powder to be heated is filled inside the mortar 1 and is heated and fired while being moved by the pusher and moving inside the furnace.

  As shown in FIG. 3, in the present invention, a part or the whole of the bottom surface of the mortar 1 is provided as a ventilation portion 9 made of a breathable material. Since the mortar 1 is made of a ceramic having excellent heat resistance, the ventilation portion 9 needs to have heat resistance, and it is necessary to prevent powder from leaking from the ventilation portion 9. For this reason, it is preferable that the ventilation portion 9 is made of a porous ceramic material having fine communication pores. However, the ventilation portion 9 may have a normal opening and may be covered with a porous plate. In FIG. 3, the ventilation portion 9 extending in the traveling direction is formed at the center of the bottom of the mortar 1. However, a plurality of ventilation portions 9 may be formed, or the entire bottom portion may be used as the ventilation portion 9. Further, a suction hole 10 is formed through the base plate 2 on which the mortar 1 is placed at the same position as the vent 9 of the mortar 1.

  Further, in the temperature raising region, a suction hole 11 is also formed in the hearth 4 which is a support surface of the sagger, and as shown in FIGS. 1 and 2, it is a differential pressure generating means through a suction pipe 12 below the suction hole 11. It is connected to an exhaust fan (not shown) outside the furnace. As many suction holes 11 in the hearth 4 are formed at each stop position of the mortar 1 as the mortar 1 and the base plate 2 slide intermittently thereon. In this embodiment, the suction hole 11 of the hearth 4 is formed elongated in the longitudinal direction of the furnace, and the suction pipe 12 is connected to the end of the suction hole 11, but is not limited to this configuration. Thus, in the sagger stop position in the temperature rising region, the ventilation portion 9 of the sagger 1, the suction hole 10 of the base plate 2, and the suction hole 11 of the hearth 4 as the sagger support surface are in the vertical direction. It overlaps at the same position and adheres to the bottom of the mortar. For this reason, the inside of the mortar 1 can be sucked by a differential pressure generating means such as an exhaust fan.

  On the other hand, in the temperature rising region, fresh gas is supplied downward from the gas supply hole 13 formed in the ceiling portion of the furnace chamber 6. The supplied gas descends toward the mortar 1, but since the mortar 1 is covered with a lid 14 for preventing the dispersion of the powder, the gap between the lid 14 and the mortar 1 or the lid 14. It slowly enters the inside of the mortar 1 through a gas flow hole (not shown) formed at the end of the mortar. When the gas is a reaction gas, the reaction with the powder proceeds inside the mortar 1.

  In this way, in the temperature rising region, a gas flow is formed from the ceiling of the furnace chamber to the lower side through the inside of the mortar 1 so that the vicinity of the powder filled with fresh gas inside the mortar 1 is formed. The generated gas generated from the powder is sucked downward along this flow and discharged outside the furnace without diffusing into the furnace chamber.

  Although the embodiment described above is an embodiment in which the present invention is applied to a base plate type pusher furnace, the present invention can also be applied to a walking beam furnace. As shown in FIG. 4, the walking beam furnace is a type of furnace in which the mortar 1 is moved by a moving beam 20 that can be moved up and down.

  In this case, the inside of the mortar can be sucked through the suction holes 22 formed in the fixed floor 21 in the temperature rising region. In this embodiment as well, fresh gas can be supplied from the ceiling of the furnace. However, as shown in FIG. It is also possible to supply intensively inside the pot 1.

  Note that it is not easy to apply the present invention to a roller hearth kiln, a mesh belt kiln, a bogie type tunnel kiln, etc. that are widely used as firing furnaces.

The advantages of the present invention are summarized as follows.
(1) Since the fresh gas introduced into the furnace efficiently contacts the object to be heated inside the pot, the amount of gas used can be reduced.
(2) Since the inside of the sagger can be actively ventilated, the temperature distribution inside the sagger becomes uniform and the firing time can be shortened.
(3) Since the generated gas generated from the heated object such as powder in the temperature rising zone can be selectively discharged outside the furnace without diffusing into the furnace, the furnace atmosphere is not polluted. Also, there are effects such as no leakage of generated gas from the furnace inlet, high concentration generated gas can be exhausted, deodorizing treatment is simple, and no generated gas flows out to the firing zone.
(4) Since fresh gas can be brought into contact with the object to be heated, the firing quality can be improved.

It is sectional drawing of the furnace width direction in the temperature rising area of a base plate type pusher furnace. It is sectional drawing of the furnace length direction in a temperature rising area. It is a disassembled perspective view, such as a mortar. It is principal part sectional drawing in the temperature rising area of a walking beam furnace. It is principal part sectional drawing which shows the example which performs the suction | inhalation to the inside of a mortar.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bowl 2 Base plate 3 Furnace body 4 Hearth floor which is a bowl support surface 5 Guide 6 Furnace room 7 Heater 8 Heater 9 Ventilation part 10 Suction hole 11 Suction hole 12 Suction pipe 13 Gas supply hole 14 Lid 20 Moving beam 21 Fixed Floor 22 Suction hole 23 Air supply pipe

Claims (6)

  In the heating method in which the object to be heated contained in the sagger is heat-treated while being moved in the heating furnace, a sagger composed of a material that allows ventilation of a part of or the entire bottom surface is used. The formed vent is brought into close contact with the bottom of the sagger, and a differential pressure is applied to the vent formed on the stool support surface by means of differential pressure from outside the furnace, and the inside of the sagger is sucked or scavenged. A heating method using a mortar characterized by:   2. The heating method using a mortar according to claim 1, wherein the inside of the mortar is sucked in a temperature range where gas is generated from the object to be heated.   3. A heating method using a mortar according to claim 1 or 2, wherein the inside of the mortar is scavenged in a maximum temperature range.   The heating furnace is a base plate type pusher furnace that moves a mortar on a base plate, and sucks the inside of the mortar through a suction hole formed in the base plate and a hearth that supports the base plate. A heating method using the mortar according to claim 2.   The heating method using a mortar according to claim 2, wherein the baking furnace is a walking beam furnace in which the mortar is moved by a moving beam, and the inside of the mortar is sucked through suction holes formed in the fixed floor. .   The heating method using the mortar according to claim 1, wherein the breathable material on the bottom surface of the mortar is a porous material.

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