JP2007039254A - Combustion synthesis method and continuous reaction equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustion synthesis method enabling continuous combustion synthesis reaction, and continuous reaction equipment used for the method. <P>SOLUTION: According to this continuous combustion synthesis method, the chain synthesis reaction of a substance is performed without needing external heating. The method comprises: a mixing process for mixing a plurality of raw materials; a charging process for charging the mixed raw material in a continuously moving conveyer type reactor; a reaction process for reacting the mixed raw material while conveying by igniting at a prescribed timing; and a takeoff process for taking off the obtained reaction product from the conveyer type reactor after cooling. The conveyer type reactor is composed of a material which does not cause oxidation reaction itself in the combustion chemical reaction in the above reaction process and also has low thermal expansivity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a combustion synthesis method and a continuous reaction apparatus used for the combustion synthesis method.

To synthesize conventional ceramics, external heating must be performed using a furnace at around 1000 ° C to 2000 ° C. For this reason, the synthesis of ceramics requires enormous energy and a large heating mechanism, which increases the manufacturing cost.
As a manufacturing method that does not perform external heating, synthesis of ceramic powder by combustion synthesis is known (Patent Document 1, Patent Document 2). The combustion synthesis method is a method of synthesizing substances in a chain manner by utilizing a large amount of chemical heat reaction released at the time of compounding without requiring external heating.

In the manufacturing method according to Patent Document 1, three kinds of raw materials, ie, one kind of metal oxide and two kinds of different metal elements, are used as starting materials, and two kinds of intermetallic compounds or non-oxide ceramics and oxide ceramics are synthesized. is doing. For example, after mixing nickel oxide powder, aluminum powder, and alumina powder into a circular shaped product using a die press, the product is placed on a carbon plate, stored in a high-pressure reaction vessel, and the molded product in an argon atmosphere. The oxidation reaction of aluminum powder is induced by igniting the upper end surface of the metal, and the combustion reaction proceeds in a chain while reacting with the excessively added aluminum of the reduced nickel to synthesize NiAl. As a result, an ingot of NiTi that is one of intermetallic compounds can be manufactured without external heating.
In the production method according to Patent Document 2, titanium powder and carbon powder are mixed at a molar ratio of 1: 1, and the obtained mixed powder is formed into a cylindrical molded body, and then placed in the air on a graphite plate. A method is disclosed in which an upper end of a body is ignited by discharge to cause a combustion synthesis reaction. By this method, a porous body having a surface layer mainly made of titanium oxide ceramics and an inside mainly made of titanium carbide ceramics has been obtained.

However, the conventional manufacturing method includes a step of mixing an oxide-based raw material and a raw material serving as an oxygen supply source at a predetermined ratio, and a step of previously forming an inorganic material mixed at a predetermined mixing ratio into a circular shape or a cylindrical shape. A combustion synthesis method comprising a step of accommodating a molded body in a reactor and a step of igniting and reacting the molded body. At least the step of molding the raw material and the step of reacting the molded body must be separated. There is. In addition, if combustion synthesis is performed in air, the graphite material may be damaged by an oxidation reaction during combustion. Therefore, it is essential to replace or degas the reaction system, and it is necessary to seal the apparatus. Further, since the combustion synthesis of the molded body after ignition has a risk of ignition and explosion, a production method using a batch type reaction apparatus has to be adopted. For this reason, production methods using batch-type reactors require quality control for each batch, and in addition to an increase in equipment costs, including an increase in the number of manufacturing processes and process safety management, there are also restrictions on improving production efficiency. There was a problem such as receiving.
Japanese Patent Laid-Open No. 5-9009 JP 2003-55063 A

  The present invention has been made to address such problems, and an object of the present invention is to provide a combustion synthesis method capable of continuously performing a combustion synthesis reaction and a continuous reaction facility used in the combustion synthesis method.

The combustion synthesis method of the present invention is a combustion synthesis method for continuously performing combustion synthesis in which substances are synthesized in a chain manner without the need for external heating by a combustion chemical reaction when raw materials are combined, The combustion synthesis method includes a mixing step of mixing a plurality of raw materials, an input step of feeding the obtained mixed raw materials into a transport reactor that continuously moves, and igniting the mixed raw materials being transported at a predetermined timing. A reaction step for reacting with each other, and an extraction step for removing the obtained reaction product from the transport reactor after cooling, and the material constituting the transport reactor is itself in the combustion chemical reaction of the reaction step. It is characterized by being a low thermal expansion material.
In the present invention, the low thermal expansion substance means a substance having a thermal expansion coefficient of 3.0 × 10 ⁻⁶ / ° C. or less.

  The mixed raw material includes at least a peroxide powder that is an oxygen supply source and a metal powder that is a heat generation source, and the charging step includes either one of the peroxide powder or the metal powder in advance and a stable raw material. This is a step of pre-mixing powder with a predetermined ratio to obtain an intermediate raw material, and then mixing the powder not used for this pre-mixing with the intermediate raw material at a predetermined ratio to obtain a mixed raw material. It is characterized by that.

  The transport speed of the transport reactor is synchronized with the speed at which combustion synthesis is propagated in the reaction process, and the transport direction is substantially opposite to the main propagation direction of the combustion synthesis reaction in the reaction process. It is characterized by.

  The ignition in the reaction step is performed at time intervals that do not interrupt the combustion synthesis reaction of the mixed raw material.

  A continuous reaction facility according to the present invention is a continuous reaction facility for performing combustion synthesis by the above-described combustion synthesis method, and a mixing device that mixes a plurality of raw materials, and the mixed raw materials are continuously conveyed at a predetermined speed. A transport reactor, an input device for charging the mixed raw material obtained by the mixing device into the transport reactor, a reaction device for igniting and reacting the mixed raw material being transported at a predetermined timing, and And a take-out device for taking out the reaction product obtained from the transport facility after cooling, and the material constituting the transport reactor does not undergo its own oxidation reaction in the combustion chemical reaction in the reaction device, and It is a low thermal expansion material.

  The combustion synthesis method of the present invention employs a raw material mixing method in which the oxide-based raw material and the oxygen supply source are not in direct contact, and is composed of a material that does not generate its own oxidation reaction in the combustion chemical reaction and is a low thermal expansion substance. In addition, the combustion synthesis reaction can be performed in the air, and the process from the raw material powder mixing step to the reaction product extraction step can be continuously performed. As a result, it has become possible to improve production efficiency, in addition to reducing equipment costs, including reducing quality control, reducing the number of manufacturing processes and managing process safety.

  The continuous reaction facility of the present invention uses a mixed raw material stabilized by a method in which the oxide-based raw material and the oxygen supply source do not come into direct contact in the raw material powder mixing step in the ceramic combustion synthesis reaction, and the combustion chemical reaction is performed on the equipment material. In this case, since a material that does not undergo its own oxidation reaction and is a low thermal expansion substance is used, it is possible to prevent ignition and explosion of the raw material in the combustion synthesis reaction and to prevent damage to the reactor due to the oxidation reaction during combustion. As a result, by using this continuous reaction equipment, it has become possible to carry out a combustion synthesis reaction in air continuously for each mixed raw material to be charged.

The combustion synthesis method of the present invention will be described with reference to FIG. FIG. 1 is a process diagram showing a combustion synthesis method. As shown in FIG. 1, the combustion synthesis method includes a mixing step 1 for mixing a plurality of raw materials serving as an element source constituting the main product, a charging step 2 for charging the mixed raw material E into the transport reactor, A transport process 3 for transporting the mixed raw material E in the transport reactor at a predetermined speed, a reaction process 4 for igniting and reacting the mixed raw material E being transported at a predetermined timing, and the obtained reaction product F. And an extraction step 5 that is taken out from the transport reactor after cooling.
In particular, in the mixing step 1, either one of the peroxide powder and the metal powder and the stable raw material powder B are premixed at a predetermined ratio to obtain an intermediate raw material C. The raw material E is obtained by mixing the powder D, which was not used for the above, at a predetermined ratio.

The transport reactor in the present invention is a movable member itself such as a conveyor, or a reaction vessel such as a crucible placed on these movable members. When the conveyor itself is used as a reactor, mixed raw materials are placed on the conveyor, and when a reaction vessel is used, the mixed raw materials are put into the reaction vessel. The material constituting these transport reactors is a low thermal expansion substance that does not undergo its own oxidation reaction at the portion in contact with the mixed raw material in the combustion chemical reaction of the above reaction step.
The material preferably has a thermal expansion coefficient smaller than that of graphite (thermal expansion coefficient 5 × 10 ⁻⁶ / ° C.), and is particularly titanate-aluminum ceramic (thermal expansion coefficient 1.2 × 10 ⁻⁶ / ° C.). Is preferred.
Focusing on the fact that the combustion synthesis method of the present invention enables a combustion synthesis method in air, which has been difficult in the past, by using a reactor of the above-described material, and continuously in the air without using a chamber or the like. Combustion synthesis is performed.

  A combustion chemical reaction is a reaction that uses a large amount of combustion heat released during the combination of raw materials without requiring external heating, and a substance is synthesized in a chain by this reaction. Examples of the combustion synthesis method of the present invention include a combustion synthesis method using an oxide-based material and an oxygen supply source as raw materials. As the reaction system of the combustion synthesis method, (i) a reaction raw material containing at least a metal powder containing a Group 4 element, a carbonate of an element containing a Group 2 element, and a peroxide of an element containing a Group 2 element is used. And (b) a reaction system using a reaction raw material containing at least a metal powder containing a Group 4 element, a carbonate of an element containing a Group 2 element, and sodium perchlorate.

The reaction system (b) may be a group 4 metal powder, a group 2 carbonate, and a group 2 peroxide alone, or a reaction product obtained by adding a group 4 metal oxide to the piezoelectric. It is preferable because of its excellent properties, dielectric properties, cost and the like. For example, when dielectric ceramics such as barium titanate (BaTiO ₃ ) and calcium titanate (CaTiO ₃ ) are synthesized, they are generated according to the following chemical reaction formula. The group 4 metal powder, the group 2 carbonate, and the group 2 peroxide, which are reaction raw materials, are blended in amounts corresponding to respective molar masses that satisfy the following chemical reaction formula.
In addition, when blending Group 4 metal oxides, blend them at a rate that allows the adiabatic flame temperature to be maintained at 1500 ° C or higher. The adiabatic flame temperature can be lowered by increasing the proportion of the Group 4 metal oxide.

Ti + 2TiO ₂ + BaCO ₃ + 2BaO ₂ → 3BaTiO ₃ + CO ₂ ↑
Ti + 2TiO ₂ + CaCO ₃ + 2CaO ₂ → 3CaTiO ₃ + CO ₂ ↑
Ti + 2TiO ₂ + BaCO ₃ + 2CaO ₂ → 3 (Ba _1/3 , Ca _2/3 ) TiO ₃ + CO ₂ ↑
Ti + 2TiO ₂ + CaCO ₃ + 2BaO ₂ → 3 (Ba _2/3 , Ca _1/3 ) TiO ₃ + CO ₂ ↑

The reaction system of (b) above is a group 4 metal powder, a group 2 carbonate, and NaClO ₄ alone, or the addition of a group 4 metal oxide to this, and the reaction product has excellent detergency. It is preferable because of its excellent piezoelectricity and dielectric properties.
For example, in the case of strontium titanate (SrTiO ₃ ), it is produced according to the following chemical reaction formula. Each reaction raw material is blended in an amount corresponding to the molar mass required for the reaction between the Group 4 metal powder and the Group 2 carbonate, but the oxygen generating substance can be blended in an amount greater than the molar mass necessary for the reaction.

Ti + SrCO ₃ + 0.5NaClO ₄ → SrTiO ₃ + CO ₂ ↑ + 0.5NaCl

  In the combustion synthesis method of the present invention, the mixing step 1 in which the oxide-based raw material and the oxygen supply source are mixed at a predetermined ratio is mixed at an atomic ratio capable of forming a final product in the reaction system (b) or (b) In this step, the raw material is mixed using a known mixing apparatus such as a ball mill, a Henschel mixer, a Laedige mixer, or a tumbler.

Further, in the mixing step 1, a pre-mixing step is provided so that the peroxide powder (reactive powder X) which is a reactive powder and the metal powder (reactive powder Y) which is also a reactive powder do not contact at the same time. It is preferable that the reactive powder X and the stable raw material powder that does not react with this are premixed to obtain a stable intermediate raw material, and then the reactive powder Y is added and mixed.
Since the reactive powder is covered with a stable raw material powder in the intermediate raw material powder, the concentration of the reactive powder in the raw material powder is low and the reaction factor is reduced. Can be dry mixed.

In the reaction system (a) or (b), the shape of the metal containing a group 4 element as a reaction raw material is preferably a fine powder, and the specific surface area is 0.01 to ² m ² / g. A preferable specific surface area is 0.1 to 0.6 m ² / g because the combustion wave propagates and is easy to handle. When the specific surface area is less than 0.01 m ² / g, the contact area between the metal powder that is a heat generation source and the peroxide that is an oxygen supply source is small, so that combustion waves may not propagate and ceramics may not be synthesized. In addition, metal powders having a specific surface area exceeding 2 m ² / g are not preferable because they are extremely active and difficult to handle.
In the present invention, the specific surface area of the metal powder is a value measured by the BET method.

Moreover, even if the average particle diameter of the metal fine powder is the same, a difference in reactivity is recognized when the specific surface area is different. That is, when a metal powder having a specific surface area larger than that of a spherical shape was used, the combustion synthesis reaction proceeded more rapidly. Examples of the shape having a large specific surface area include particles having a plurality of irregularities formed on the surface of spherical particles, particles having an irregular shape as a whole, or a combination thereof.
The average particle size that can be used in the present invention is 150 μm or less, preferably 0.1 to 100 μm. If it exceeds 150 μm, mixing with other raw materials will be insufficient, and combustion waves may not propagate. An image analysis method is preferable as a method for measuring the average particle diameter of particles having irregularities formed on the surface or an irregular shape.

The charging step 2 for charging the mixture mixed at a predetermined ratio is a step for charging the mixed powder into the transport reactor. When the conveyor itself is used as a reactor, the mixed raw materials are continuously spread uniformly on the conveyor. In addition, when using reaction vessels, a predetermined amount of the mixed raw material is charged into each reaction vessel.
The mixed raw material E is charged after being pelletized as necessary. Moreover, you may perform the process of pressing into a pellet form within reaction container after injection | throwing-in. For pressing into a pellet, a polymer material such as polyvinyl alcohol can be used as a binder.

The conveyance process 3 is a process of conveying the mixed raw material E at a predetermined speed.
When the mixed raw materials are directly fed onto the conveyor, the transport speed in the transport process is set to a speed synchronized with the speed at which the combustion synthesis is propagated, and the transport direction is substantially opposite to the main propagation direction of the combustion synthesis reaction. Is preferred. In this case, by igniting the leading end of the mixed raw material that has been conveyed, a combustion synthesis reaction with an adiabatic flame temperature of 1500 ° C or higher starts, and a non-reacted mixed raw material is conveyed as a combustion synthetic wave. Since it mainly propagates in the direction, it is possible to cause a combustion synthesis reaction continuously.
In addition, the speed at which the combustion synthetic wave propagates can be reduced by increasing the proportion of the group 4 metal oxide or the like that becomes the reaction diluent in the mixed raw material.
In the case of a semi-batch type in which a reaction vessel such as a crucible is placed on a conveyor and a combustion synthesis reaction is performed for each reaction vessel, the conveyance speed can be determined as appropriate.
Further, by preheating the mixed raw material before the reaction step, combustion propagation is facilitated even in a system in which the reaction does not proceed easily. Preheating is performed by installing a heater, a far-infrared heater, etc. in the front part of the reaction apparatus, for example.

The method of igniting the mixed raw material in the reaction step 4 is not particularly limited as long as the mixed raw material can ignite and generate heat. In the present invention, since the oxidation reaction does not occur in the combustion chemical reaction and the transport reactor using the material of the low thermal expansion material is used, the carbon film is ignited to generate heat and contact the mixed powder. The method of causing the heat to ignite is preferable because it is excellent in handling.
Ignition is performed at time intervals that do not interrupt the combustion synthesis reaction. In addition, when charging the mixed raw material into the reaction vessel, it is performed once for each reaction vessel.
In the reaction step 4, the reaction product obtained by the combustion synthesis reaction is preferably cooled by natural cooling or forced cooling.

  The take-out process 5 is a process of taking out the reaction product after the combustion synthesis or the reaction vessel containing the reaction product from the transport facility. The taken out reaction product becomes a product through other processes such as pulverization and foreign matter removal.

  A continuous reaction facility according to an embodiment of the present invention will be described with reference to FIG. FIG. 2 is a diagram showing a flow of the continuous reaction facility. As shown in FIG. 2, the continuous reaction equipment includes a premixing device 6 that preliminarily mixes one of a peroxide powder and a metal powder and a stable raw material powder to obtain an intermediate raw material powder, A mixing device 7 for mixing the powder not used for mixing with the intermediate raw material powder at a predetermined ratio, a charging device 8 for charging the mixed raw material powder, and a reaction vessel 10a charged with the mixed raw material at a predetermined speed. And a reaction device 10 that ignites and reacts the mixed raw material being conveyed at a predetermined timing, and a take-out device 11 that extracts the reaction product from the conveyance reactor after cooling. In the case of this example, a transport reactor is constituted by the reaction vessel 10a and the belt conveyor 9.

The premixing device 6 is a device 6a that measures one of the raw material peroxide powder and metal powder A, a device 6b that measures stable raw material powder B, and measures A and B at a predetermined ratio. And a device 6c for storing the intermediate raw material powder C preliminarily mixed. The mixing device 7 measures the powder D not used for the premixing, and measures the intermediate raw material powder C and mixes it with the powder D. And a device 7b for storing the mixed raw material E.
For mixing these raw materials, a known mixing apparatus such as a ball mill, a kneader, a ribbon blender, a Henschel mixer, a Ladige mixer, and a tumbler can be used. In order to continuously produce the mixed raw material at a predetermined cycle, it is preferable to incorporate an automatic weighing machine such as an auto feeder into the mixing device. As a mixing device, it can have the functions of mixing and storage of raw materials, and in combination with an automatic weighing machine, use a ribbon blender or Henschel mixer that can easily automate the series of operations of raw material weighing, mixing, storage and charging. Is preferred.

The mixed raw material E is charged by a charging device 8 into a plurality of continuously adjacent reaction vessels 10a arranged on a belt conveyor 9 that conveys at a predetermined speed. The charged mixed raw material E is transferred to the reaction apparatus 10 by the transfer facility 9.
The reactor 10 includes an ignition jig 10b, an airtight structure 10c in which raw materials and reaction products scattered from the reaction vessel 10a by the combustion synthesis reaction do not leak out from the reactor 10, and inert gas when an emergency abnormality occurs. And an inert gas supply jig 10d to be supplied. The airtight structure 10 c is installed from the inlet to the outlet of the reaction apparatus 10. The mixed raw material E conveyed to the reaction apparatus 10 is ignited by an ignition jig 10b and a combustion synthesis reaction starts in the reaction vessel 10a. Ignition is performed once for each reaction vessel.

The reaction product F obtained after the completion of the combustion synthesis reaction can be naturally cooled in an inert gas stream. The inert gas also serves to prevent the ignition / explosion due to abnormal combustion of the mixed raw material E by sealing the inside of the reaction apparatus 10 with the airtight structure 10c of the reaction apparatus 10. In the present invention, since various safety measures such as the raw material mixing method, the reaction vessel material and the speed control of the combustion synthetic wave are taken, it is usually unnecessary to use it except when an emergency abnormal situation occurs.
The cooled reaction product F is transported to the take-out device 11, and a transfer jig 11b for taking out the reaction vessel 10a containing the reaction product F and the scattered reaction product F recovered by the recovery jig 11a. Is taken out by
FIG. 2 is an example in which the mixed raw material charging device 8 to the take-out device 11 are linearly arranged, but these facilities can also be arranged in a circular circuit shape.

The material of the reaction vessel 10a is a material in which an oxidation reaction of the reaction vessel itself does not occur during the raw material combustion synthesis reaction. Further, since the combustion synthesis reaction is completed in a relatively short time, it is preferable that the thermal expansion characteristics are excellent.
In addition, the ignition for starting the combustion synthesis reaction is often performed by energizing the carbon film to ignite, and in this case, in order to prevent the reaction vessel from being damaged by the contact of the carbon film, the material of the reaction vessel is made of an insulating material. Preferably there is.

As a reaction vessel of the continuous reaction equipment of the present invention, titanate-aluminum ceramic is a preferable material because it has little thermal expansion and does not cause an oxidation reaction during a combustion synthesis reaction. Examples of titanate-aluminum ceramics include Al ₂ TiO ₅ .
Examples of the reaction vessel using the above materials include a crucible, a reaction vessel similar to a crucible, a square shallow dish, a bat, and a setter. Moreover, the said material of this invention can be used also for the board | substrate etc. which install in the reactor and mount the material shape | molded in the column shape etc. In addition, when mixing raw material is directly injected | thrown-in on a belt conveyor and combustion synthesis reaction is raise | generated on this belt conveyor, a belt conveyor is formed with the said material.

Example 1
A reaction vessel made of titanic acid-aluminum ceramic (Recogit manufactured by Aucera Corp.) was used as a reaction vessel, and was placed on a belt conveyor and subjected to a combustion synthesis reaction in air. The thermal expansion coefficient of the reaction vessel used was 1.2 × 10 ⁻⁶ / ° C.
The raw materials used were 100 moles of Ti metal (specific surface area 0.3 m ² / g), 100 moles of SrCO ₃ and 50 moles of NaClO ₄ . These raw materials were mixed for 3 minutes using a Henschel mixer, scraped off the powder adhering to the wall surface, and then mixed again for 3 minutes. This was repeated a total of 3 times, and then stored in the raw material charging device.
1 kg of the mixed powder from the raw material charging apparatus was charged into the reaction vessel 1 arranged on the belt conveyor, and the shape was adjusted in the reaction vessel using a forming jig. This operation was repeated 5 times, and the first reaction vessel was transported to the ignition position. Ignition was performed by bringing the carbon film for ignition into contact with the tip of the mixed raw material that has been conveyed. The combustion wave propagated to the mixed material in the reaction vessel by ignition, and the combustion synthesis reaction in the first reaction vessel was completed in about 10 seconds. The second reaction vessel was transported to the ignition position and ignited in the same manner as the first reaction vessel, causing a combustion synthesis reaction. This operation was performed up to the fifth reaction vessel, and the reaction product and by-product (NaCl) that had been cooled and conveyed were sequentially taken out from the take-out device. In addition, the damage by the oxidation reaction of the reaction vessel did not occur during the combustion synthesis. The reaction product was pulverized using an alumina mortar to obtain an unwashed ceramic powder having an average particle size of 1 μm.
The obtained unwashed ceramic powder was sufficiently washed with water, and NaCl adhered to the powder was removed to obtain a ceramic. When the crystal phase of the obtained ceramic powder was identified using an X-ray diffractometer (XRD), it was SrTiO ₃ .

Example 2
A reaction vessel made of titanic acid-aluminum ceramic (Recogit manufactured by Aucera Corp.) was used as a reaction vessel, and was placed on a belt conveyor and subjected to a combustion synthesis reaction in air. The thermal expansion coefficient of the reaction vessel used was 1.2 × 10 ⁻⁶ / ° C.
The raw materials used were 100 moles of Ti metal (specific surface area 0.3 m ² / g), 200 moles of TiO ₂ , 100 moles of BaCO ₃ and 200 moles of BaO ₂ . These raw materials were mixed for 3 minutes using a Henschel mixer, scraped off the powder adhering to the wall surface, and then mixed again for 3 minutes. This was repeated a total of 3 times, and then stored in the raw material charging device.
Using this raw material, the same operation as in Example 1 was performed, and the reaction products cooled and conveyed were sequentially taken out from the take-out device. In addition, the damage by the oxidation reaction of the reaction vessel did not occur during the combustion synthesis.
The synthetic powder was pulverized using an alumina mortar to obtain a ceramic powder having an average particle size of 1 μm. When the crystal phase of the obtained ceramic powder was identified using an X-ray diffractometer (XRD), it was BaTiO ₃ .

Comparative Example 1
Combustion synthesis was performed in air using the same raw materials and method as in Example 1 except that a graphite reaction vessel (IG-11 manufactured by Toyo Tanso Co., Ltd.) was used as the reaction vessel. As a result of X-ray diffraction, TiC, which is a reaction product with the graphite reaction vessel, was detected in the obtained ceramic powder in addition to SrTiO ₃ .

Comparative Example 2
Combustion synthesis was performed in air using the same raw materials and method as in Example 1 except that an alumina reaction vessel (SSA-S manufactured by Nikkato Co., Ltd.) was used as the reaction vessel. The thermal expansion coefficient of alumina was 7 × 10 ⁻⁶ / ° C., the deformation of the reaction vessel could not follow the rapid temperature change during the reaction, the reaction vessel was damaged, and the synthetic powder was scattered.

Comparative Example 3
Combustion synthesis was performed in air using the same raw materials and method as in Example 1 except that a reaction vessel made of zirconia (YSZ-8 manufactured by Nikkato Co., Ltd.) was used as the reaction vessel. The thermal expansion coefficient of zirconia was 9.5 × 10 ⁻⁶ / ° C., the deformation of the reaction vessel could not follow the rapid temperature change during the reaction, the reaction vessel was damaged, and the synthetic powder was scattered.

  The combustion synthesis method and continuous reaction facility of the present invention can be suitably used for mass production of ceramics by combustion synthesis reaction.

It is process drawing which shows the continuous combustion synthesis method of this invention. It is a figure which shows the flow of the continuous reaction equipment which concerns on one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mixing process 2 Input process 3 Conveying process 4 Reaction process 5 Extraction process 6 Preliminary mixing apparatus 7 Mixing apparatus 8 Input apparatus 9 Conveyor 10 Reactor 10a Reaction container 10b Ignition jig 10c Airtight structure 10d Inert gas supply jig 11 Extraction apparatus 11a Recovery jig 11b Transfer jig A One of peroxide powder and metal powder B Stable raw material powder C Intermediate raw material D Raw material powder not used for A E Mixed raw material F Reaction product

Claims (5)

A combustion synthesis method that continuously performs combustion synthesis in which materials are synthesized in a chain without the need for external heating by a combustion chemical reaction when raw materials combine,
The combustion synthesis method includes a mixing step of mixing a plurality of raw materials, an input step of charging the obtained mixed raw materials into a transport reactor that continuously moves, and igniting the mixed raw materials being transported at a predetermined timing. And a reaction step of reacting with each other, and an extraction step of taking out the obtained reaction product from the transport reactor after cooling,
The material constituting the transport reactor is a combustion synthesis method characterized in that it does not undergo its own oxidation reaction in the combustion chemical reaction of the reaction step and is a low thermal expansion substance.   The mixed raw material includes at least a peroxide powder that is an oxygen supply source and a metal powder that is a heat generation source, and the charging step includes either one of the peroxide powder or the metal powder in advance and a stable raw material. This is a step of pre-mixing the powder with a predetermined ratio to obtain an intermediate raw material, and then mixing the powder not used for this pre-mixing with the intermediate raw material at a predetermined ratio to obtain a mixed raw material The combustion synthesis method according to claim 1.   The transport speed of the transport reactor is synchronized with the speed at which combustion synthesis is propagated in the reaction process, and the transport direction is substantially opposite to the main propagation direction of the combustion synthesis reaction in the reaction process. The combustion synthesis method according to claim 1 or 2, characterized in that.   4. The combustion synthesis method according to claim 1, wherein the ignition in the reaction step is performed at a time interval that does not interrupt the combustion synthesis reaction of the mixed raw material. A continuous reaction facility for performing combustion synthesis by the combustion synthesis method according to any one of claims 1 to 4,
A mixing device for mixing a plurality of raw materials, a transport reactor for continuously transporting the mixed raw material at a predetermined speed, and a charging device for charging the mixed raw material obtained by the mixing device into the transport reactor; A reaction device for igniting and reacting the mixed raw material being conveyed at a predetermined timing, and a take-out device for removing the obtained reaction product from the conveyance reactor after cooling,
The continuous reaction equipment characterized in that the material constituting the transport reactor is a low thermal expansion substance and does not undergo its own oxidation reaction in the combustion chemical reaction in the reaction apparatus.

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