JPH08309179A - Method and device for thermal treatment - Google Patents

Abstract

PURPOSE: To conduct thermal treatment preventing powder from scattering in a thermal treatment device without requirement of complicated processes by spraying a liquid over a stationary powder layer as a raw material, and treating the powder thermally in an air current. CONSTITUTION: A liquid spraying device consists of a spray liquid storage tank 36, a liquid feed pump 35 and a spraying nozzle 34. A plurality of units of the spraying nozzle 34 are installed almost orthogonally in the forward moving direction of a container 8 for transport, so that the spraying of a liquid is achieved in a fan-shape. In addition, a raw material powder is deposited in a stationary state inside the container 8. Further, after the liquid such as water is sprayed from the spraying nozzle 34, the powder is transported to a heating furnace 10 using a transport means 3, and then is thermally treated by a heating means 3 while a gas is inducted. Thus it is possible to carry out the thermal treatment with a concurrent action to prevent powder from scattering in a thermal treatment device. It is also possible to achieve an industrially advantageous continuous thermal treatment either by circulating the plural units of the container 8 for transport or by driving a belt for transport in a circulatory fashion. The velocity of an air current near the surface of a stationary powder layer in the thermal treatment layer is 0.1 to 50m/s. The preferable bulk specific gravity is 0.01 to 2.0g/cc and the most preferable specific gravity is 0.1 to 1.0g/cc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for industrially heat treating powder raw materials. For more information,
The present invention relates to a heat treatment method and a heat treatment apparatus capable of performing heat treatment while preventing powder from scattering in the heat treatment apparatus.

[0002]

2. Description of the Related Art When a powder raw material is heat-treated, the powder is scattered under an air flow, which causes a decrease in yield and troubles of a heat treatment apparatus. Therefore, in order to enable stable heat treatment, it is necessary to suppress the scattering of the powder raw material.

Conventionally, as a heat treatment method for powder raw materials, the methods described in JP-A-60-161378, JP-B-1-52442 and JP-A-3-164422 can be mentioned.

Japanese Unexamined Patent Publication (Kokai) No. 60-161378 proposes a method of forming a raw material powder, coating the powder with a specific composition, and heating the powder to obtain a sintered body.

Japanese Patent Publication No. 1-52442 proposes a method in which the raw material powder is granulated and formed into agglomerates into 0.5 to 30 mm granulated particles, which are then heated and reduced while a reducing gas is passed through the granulated particles. ing.

In JP-A-3-164422, crystalline amorphous sodium silicate obtained by spray drying is heated in an adiabatic internal heating rotary tubular furnace to obtain crystalline sodium silicate. At this time, a method has been proposed in which the silicate compound powder is collected by a filter by suction from a rotary tubular furnace.

[0007]

However, the method described in JP-A-60-161378 is not general because it requires a molding step and can be applied only to sintering of a specific composition. Further, the method described in Japanese Patent Publication No. 1-52442 requires a granulating step with a granulator and requires maintenance of the granulating apparatus. Also,
In the method described in JP-A-3-164422,
It is disclosed that the scattered powder in the internal heating rotary tubular furnace is sucked and collected by a filter, but maintenance is also required due to the need for filter equipment and the clogging of the filter. There are drawbacks.

The present invention has been made in view of the above problems, and provides a heat treatment method and a heat treatment apparatus capable of performing heat treatment while preventing powder scattering in the heat treatment apparatus without requiring complicated steps. The purpose is to provide.

[0009]

As a heat treatment apparatus, the present inventors have found that the above problems can be solved by using an apparatus capable of heat treatment after spraying a liquid on a stationary powder layer as a raw material. Completed the invention.

That is, the gist of the present invention is: (1) In the method of heat treating a stationary powder layer under an air flow, the liquid is sprayed on the surface of the stationary powder layer as a raw material, and then the heat treatment is performed. Method, (2) The heat treatment method according to (1), wherein the liquid sprayed on the surface of the stationary powder layer is water.
(3) The heat treatment method according to (1) or (2) above, wherein the liquid sprayed on the surface of the stationary powder layer is a solution or suspension containing the same powder components as the stationary powder layer. )
The heat treatment method according to any one of (1) to (3) above, wherein the air velocity in the vicinity of the surface of the stationary powder layer in the heat treatment apparatus is 0.1 m / s to 50 m / s, And a spraying device for spraying a liquid on the surface of the stationary powder layer held in the container, a gas inlet / outlet, a carrier container inlet / outlet, and heating means arranged to heat the inside. A heating furnace and a roller conveyor having a driving roller are arranged endlessly or so that both ends are close to each other, and a transfer device, part of which is installed in the heating furnace, and a transfer container are transferred to the product discharge position. Then, after reversing, the heat treatment device equipped with a transfer / reversal device that transfers the transfer container onto the transfer device again is used. Supply to a static powder layer The heat treatment method according to any one of (1) to (4) above, in which a liquid is sprinkled on the surface to heat the raw material, and (6) the heat-treated product to be produced is represented by the general formula xM ₂ O · ySiO ₂ · zM. 'O (however, M represents Na and / or K, M'represents Ca and / or Mg, and y
/X=0.5 to 3.5 and z / x = 0 to 1.0. )
(7) A heat treatment method according to any one of (1) to (5), (7) a spraying device for spraying a liquid onto the surface of a stationary powder layer held in a transport container to which a raw material is supplied, and a gas A heating furnace having an inlet and an outlet of the container, an inlet and an outlet of the transport container, and a heating unit arranged to heat the inside,
A plurality of transfer containers are connected to the endless power transfer member, and a transfer device is provided so that a part of the transfer container passes through the heating furnace. The power transfer member is cyclically driven to transfer the transfer container. Meanwhile, a raw material powder is supplied to a carrier container to form a stationary powder layer, and a liquid is sprayed on the surface of the carrier to heat treat the raw material, and (8) a carrier container to which the raw material is supplied. Heating furnace having a spraying device for spraying a liquid on the surface of a stationary powder layer held therein, a gas inlet and outlet, an inlet and outlet of a transport container, and heating means arranged to heat the inside. And a roller conveyor having a driving roller is arranged endlessly or so that both ends thereof are close to each other, a part of which is arranged in a heating device, and a transfer container is transferred to a product discharge position and inverted. After that, re-install the transport container. Equipped with a transfer / reversal device for transferring onto the transfer device, the transfer container is transferred by the rotation of the drive roller and is circulated to supply the raw material powder to the transfer container to form a stationary powder layer, and the surface thereof is formed. The present invention relates to a heat treatment apparatus capable of spraying a liquid and heat treating a raw material.

The present invention will be described in detail below. The heat treatment method of the present invention is a method of heat-treating a stationary powder layer under an air flow, characterized in that the liquid is sprayed on the surface of the stationary powder layer as a raw material, and then the heat treatment is performed.

Here, heat treatment means oxidation, reduction, dehydration,
It means all treatment operations involving heating such as crystallization, sintering, firing, etc., and is not particularly limited depending on the type of chemical or physical change accompanying the heat treatment. Therefore, the type of raw material powder and gas used, the treatment temperature, the treatment time, etc. are appropriately selected according to the type of treatment accompanied by the above-mentioned chemical changes.

The powder raw material used in the heat treatment method of the present invention is not particularly limited as described above, but the bulk specific gravity of the static powder layer formed is 0.01 g / cc to 2.0.
g / cc is preferable, and more preferably 0.05 g / cc
~ 1.5 g / cc, more preferably 0.1 g / cc ~
It is 1.0 g / cc. The bulk specific gravity of the stationary powder layer is 0.01
When it is less than g / cc, the required amount of the liquid sprayed on the surface of the stationary powder layer increases, and the amount of heat required for vaporizing the liquid increases. Further, when it is more than 2.0 g / cc, the scattering of the powder itself is small, and therefore when it is 2.0 g / cc or less, the effect of the method of the present invention becomes remarkable. The stationary powder layer refers to a state in which individual powder particles do not substantially flow or the like during transportation, and includes, for example, a powder that is stationary while being transported on a belt conveyor.

The composition of the powder is not particularly limited, but it is preferably applied to a silicic acid compound having a fixing property by spraying a liquid. In this case, in particular, the heat-treated product to be produced has the general formula xM ₂ O · ySiO ₂ · zM ′.
In O (however, M shows Na and / or K, M'shows Ca and / or Mg), y / x = 0.5-.
3.5 and z / x = 0 to 1.0 are preferable, and more preferably y / x = 0.5 to 2.0 and z / x = 0.
It is 005 to 1.0.

These amorphous or crystalline silicic acid compounds can be used for various purposes. For example, crystalline silicic acid compounds are known to be used as a water softening agent in the general formula. .

As the gas for the heat treatment under the air flow, for example, a gas such as oxygen or hydrogen is used in a gas-solid reaction such as oxidation or reduction, and a gas such as air or an inert gas is used in the dehydration to remove evaporated water. Even when a replacement gas such as the above is normally flowed, and the heating system of the heating device (hereinafter referred to as a furnace) is a hot air circulation system, a gas flow usually exists in the furnace.

The air velocity in the vicinity of the surface of the stationary powder layer at this operating temperature is preferably 0.1 to 50 m / s, more preferably 0.5 to 10 m / s. When the air velocity is less than 0.1 m / s, almost no powder is scattered,
When it is larger than m / s, it becomes difficult to form a stationary powder layer depending on the specific gravity of the powder.

The method of spraying the liquid in the present invention is not particularly limited as long as the liquid can be sprayed on the surface of the stationary powder layer. However, due to the uniformity of the sprayed state, the pressure nozzle or the two-fluid nozzle is used. A method of using a spray nozzle such as the above is preferable.

FIG. 1 is a schematic diagram showing an example of the operation (the upper figure is a perspective view and the lower figure is a plan view). In this way, a plurality of spray nozzles for spraying the liquid in a fan shape are installed in a direction substantially orthogonal to the traveling direction of the transport container, and the fan surface formed by the spray liquid gives a slight angle to the nozzle installation direction. It is preferable from the viewpoint of spraying uniformity and spraying efficiency to prevent the contact of the sprayed particles.

As the liquid to be sprayed, water, a solvent that easily evaporates such as methanol or ethanol, or a solution or suspension containing the same powder component as that of the stationary powder layer in consideration of the residue after heat treatment is preferable. Is. In addition to the raw material powder and gas, a third component necessary for the treatment may be added depending on the type of treatment.

The amount of the liquid sprayed is preferably 5 to 1000 g / m ² , more preferably 10 to 500 g / m ² , and still more preferably ²⁰ to 3 with respect to the surface area of the stationary powder layer.
It is 00 g / m ² . If the amount of liquid sprayed is less than 5 g / m ² , it is difficult to evenly spray the spray liquid, and 1000 g / m ²
If it is more than m ^{3, the} heat load required to evaporate the spray liquid increases.

In the heat treatment method of the present invention, the above-mentioned raw material powder is supplied to a carrying member or a carrying container to form a stationary powder layer, and the liquid is sprayed on the surface as described above, It is characterized in that it is heat-treated under an air stream.
In this case, the heat treatment can be continuously performed by continuously supplying the raw material powder. In the present invention, by spraying the liquid in this manner, before the evaporation of the liquid or when the liquid does not evaporate, the solid powder hardly scatters due to the action of wetting of the solid-liquid, and after the evaporation of the liquid. Agglomeration and sticking occur between the individual particles forming the stationary powder layer, so that scattering of the solid powder is less likely to occur.

Next, the apparatus used in the heat treatment method will be described by exemplifying a mode having the most basic apparatus configuration (mode a). The heat treatment apparatus according to this aspect a includes a spraying device for spraying a liquid on the surface of a stationary powder layer held in a container for supplying raw materials, an inlet and an outlet for gas, and an inlet for a container for supplying raw materials. And an outlet, and a heating furnace having a heating means arranged to heat the inside, and a carrying means for passing the carrying container through the heating furnace, and continuously supplying the raw material powder to the carrying container, After spraying the liquid on the surface, it is possible to heat-treat the raw material while transporting the transport container in the heating furnace under the flow of gas.

This will be described with reference to FIG. 2 which is a schematic explanatory view thereof. The heating furnace 10 includes a gas inlet 4 and a gas outlet 5, an inlet 6 ′ of a transfer container for supplying raw materials and a transfer container. It has an outlet 7 ', around which the heating means 3 is provided.

The spraying device includes a spraying liquid storage tank 36 and a liquid sending pump 3.
5. The spray nozzle 34 is provided so that the spray liquid can be sprayed on the surface of the stationary powder layer supplied to the transport container before the transport container 8 is transported into the heating furnace. There is. The method of spraying is as described above (see FIG. 1).

The transfer means 1 is arranged in the heating furnace so that the transfer container 8 can pass therethrough. At this time, the transport container may be simply placed on the transport member, or may be connected / fixed to the transport member, and the transport container is transported by driving the transport member. Is configured. Further, the driving device for transportation is not particularly limited, and for example, a rotation speed variable motor is suitable. In this aspect, the heating furnace 10 is provided with a raw material supply port and a product discharge port so that the raw material can be supplied to the transport container and the product can be discharged from the transport container inside the heating furnace 10. May be.

Further, in the present invention, as the transfer means 1, a device configured to connect a plurality of transfer containers to an endless power transmission member and drive them in circulation to transfer the transfer containers may be used. In consideration of efficiency, such a mode is preferable. In that case, specifically, there are a mode b in which a part (one-way) of the container conveying means is provided in the heating furnace, and a mode c in which all of them are provided in the heating furnace. Hereinafter, each aspect will be described based on FIGS. 3 and 4.

The heat treatment apparatus according to the embodiment b includes a spraying device for spraying a liquid on the surface of a stationary powder layer held in a transport container to which raw materials are supplied, a gas inlet and outlet, and a raw material to be transported. A heating furnace having an inlet and an outlet of the container and a heating means arranged to heat the inside, and a plurality of transfer containers are connected to the endless power transmission member, and a part of the container is arranged to pass through the heating furnace. Equipped with a transportation means,
The raw material powder is continuously supplied to a container for transportation to form a stationary powder layer, and a liquid is sprayed on the surface thereof, and then the power transmission member is cyclically driven under the flow of gas to be transported in the heating furnace. This makes it possible to heat the raw material while transporting the container for use, and an example thereof is shown in a schematic view in FIG.

The heat treatment apparatus according to the aspect c is a spraying apparatus for spraying a liquid on the surface of a stationary powder layer held in a container for feeding raw materials, gas inlets and outlets, raw material inlets and products. A discharge furnace and a heating furnace having a heating means arranged to heat the inside, and a transfer means installed in the heating furnace and having a plurality of transfer containers connected to an endless power transmission member. While supplying the raw material powder to the carrier container to form a stationary powder layer and spraying a liquid on the surface thereof, while circulating the gas, the power transmission member is circulated to drive the carrier container. The raw material can be heat-treated, and an example thereof is shown in a schematic diagram in FIG. This mode is characterized in that it is provided in the heating furnace including the circulation drive unit and can be heated even in the return path, so that the heating time can be lengthened even with the same furnace length as in the apparatus of FIG.

The carrying means in the above modes b and c is constructed by connecting a plurality of carrying containers to an endless power transmission member. More specifically, the transport container 8 is connected to an endless power transmission member 19 such as a chain in a format as illustrated in the upper diagram of FIG. 5, and is configured to be transported while circulating. ing. At this time, if the connection part is fixed, the container is reversed in the return path (see the lower diagram of FIG. 5), but the connection part is connected by a bearing or the like, and the transport container is rotatable around the connection part. Does not reverse even on the return trip. As the endless power transmission member, if the power of the drive unit can be transmitted to convey the container for conveyance,
The shape and the like are not particularly limited. Further, the driving device for transportation is not particularly limited, and for example, a rotation speed variable motor is suitable.

Further, in the present invention, a method of transporting the transporting container in the heating furnace by using a roller conveyor having a driving roller may be used. In that case, the roller conveyor may be endless or both ends thereof may be close to each other. Arranged, after transporting the transport container placed on it and passing through the heating furnace, the product is taken out, and then the transport container is placed again on the roller conveyor and circulated (aspect d),
It is more preferable in terms of ease of scale-up.

The heat treatment apparatus according to the aspect d includes a spraying device for spraying a liquid on the surface of a stationary powder layer held in a transport container for feeding raw materials, a gas inlet and an outlet, and a transporting material for feeding raw materials. A heating furnace having an inlet and an outlet of the container and a heating means arranged to heat the inside, and a roller conveyor having a driving roller are arranged endlessly or in such a manner that both ends thereof are close to each other, and a part thereof is heated. Equipped with a transfer means arranged in the furnace and a transfer / reversal means for transferring the transfer container to the product discharge position and inverting it, and then transferring the transfer container again onto the transfer means. After supplying the powder to the transfer container to form a stationary powder layer and spraying the liquid on the surface, the raw material is heated in the heating furnace while the transfer container is being circulated by circulating the driving roller while the gas is flowing. Heat treatment It is obtained by allowing the door, a schematic view of one example in FIG. 7 shows the XX 'section of FIG. 6, and FIG. 8 shows the YY' section of FIG.

This device comprises a rotatable support roller 29.
A roller conveyor having drive rollers 30 forcibly rotating is arranged in a rectangular shape so that both ends thereof are close to each other, and a part thereof is arranged in a heating furnace. This drive roller rotates in the same direction via a sprocket (gear). The chain can be hung with a double sprocket so that the driving force can be sequentially transmitted, or a long chain can be used to drive all together, but if the distance becomes long, the slack of the chain will increase and problems such as idling will occur. Easy to cause. When a double sprocket is used, it is not always necessary to change the chain for each one, and it is also possible to change the chain for each multiple sprocket.

At least one drive roller needs to be always under the transport container as an interval for disposing the drive roller. For this purpose, a length smaller than the length L of the transport container in the moving direction is required. Need a spacing. In particular, it is preferable that two or more driving rollers are always under the container (a distance of L / 2 or less).

As the transfer / reversal means 28 for the transfer container, when the transfer container coming out of the heating furnace reaches the position P1 in FIG. 6, the arm of the transfer / reversal means 28 sandwiches the side surface of the container and holds it as it is. The container for transportation is brought to the product discharge position P2 by rotating 90 ° in the horizontal direction. At P2, the product in the container is discharged by rotating it upside down 180 ° and inverting it. After the product has been discharged, the transport container is turned up again by rotating 180 °, then is rotated 90 ° in the horizontal direction to release the transport container at the position P3, and the transport container is placed on the transport means again. Placed. A vibrator and a knocker can be used together when the product is discharged.

Further, in the present invention, an endless belt conveyor may be used as a driving device to convey the raw material powder in the heating furnace. In that case, an endless belt conveyor may be used to circulate and drive it. This embodiment (aspect e) is preferred.

The heat treatment apparatus according to the embodiment e includes a spraying device for spraying a liquid on the surface of a stationary powder layer held on a conveyor belt for supplying raw materials, an inlet and an outlet for gas, and a conveying means for supplying raw materials. A heating furnace having an inlet and an outlet of the belt, and heating means arranged to heat the inside, and a conveying means for passing the conveyor belt through the heating furnace,
While continuously supplying the raw material powder onto the conveyor belt to form a stationary powder layer and spraying a liquid on the surface thereof, while circulating the gas, the belt conveyor is cyclically driven to convey the raw material powder. As shown in FIG.
An example of this is shown in FIG.

The method of heating means is not particularly limited as long as the raw material can be heated to the heat treatment temperature in any of the embodiments. For example, a method of directly blowing a combustion gas, an indirect heating with an electric heater or a combustion gas, or the like can be used, and a region where the heating temperature is 300 ° C. or lower may be heated by steam or a heat medium. In the present invention, for the purpose of keeping the heat treatment temperature in the heating furnace constant, heat insulation is usually performed by using a heat insulating material.

The material of the carrying container (bucket) or the carrying belt is not particularly limited as long as it has appropriate heat resistance in any of the embodiments, and the shape thereof is not limited. In the above, there is no particular limitation as long as it can hold the raw materials. As an example of the shape of the transport container, the cross-sectional shape when viewed from the side surface vertical direction or the front surface vertical direction with respect to the moving direction of the container is not particularly limited, such as a quadrangle, a triangle, a trapezoid, a semicircle, and a semioval. However, in the modes a and d, the bottom is preferably flat, and particularly in the mode d, the bottom is preferably flat because the transport container needs to be transported by the drive roller.

Further, it is preferable to provide a rotary blade 23 or the like as shown in FIG. 10 as scraping means for the purpose of separating the heat-treated product from the transport container. The shape and material of the rotary blade are not particularly limited as long as they have appropriate heat resistance and can scrape the heat-treated product from the transport container, and usually metal, ceramics or the like is used. The rotary scraping blade is preferably provided in the vicinity of the outlet of the transport container in the apparatus shown in FIGS. 2 to 4 and the product outlet in FIG.

Further, as shown in FIG. 11, the bottom plate 24 of the container
Alternatively, the product 25, which is the content of the container, may be taken out by pressing the bottom plate in the direction of B while making the container movable. Also,
The bottom plate of the transport container may have a structure capable of moving in the depth direction, and a mechanism for pushing out the crystalline silicic acid compound generated together with the bottom plate may be adopted.

Further, in the present invention, a releasing agent may be used in order to facilitate taking out the heat-treated product. Specific examples thereof include a method of mixing with the raw material and a method of previously or continuously coating the inner surface of the carrying container, but the coating method is preferable because the effect is exhibited in a smaller amount.
In particular, spray the release agent into the transfer container at the upstream side of the position where the raw material is supplied into the transfer container so that the heat-treated product can be taken out only by turning the transfer container upside down (reversing). A method of applying continuously or intermittently with a nozzle or the like is more preferable.

By such a method, the heat-treated product can be taken out of the transport container by reversing the transport container connected to the endless power transmission member, and the heat treatment is industrially advantageous with a simple operation. can do. At this time, as a method of reversing the transport container, for example, a method of fixing the endless power transmission member such as a chain and the transport container in a non-rotatable manner as described above, and the like can be mentioned.

As the release agent, boron nitride, mica, sericite, talc, etc., which have a scaly crystal form, are effective, but in addition, C, Mg (OH) ₂ , Al (O ₂
H) _{3 and} other inorganic hydroxides, MgO, Al ₂ O ₃ , SiO
Inorganic oxides such as ₂ , other inorganic salts, thermal decomposition temperature is 40
Resins at 0 ° C. or higher are included.

The continuous heat treatment mode has been described above.
An example of the batch type embodiment is as follows (aspect f). FIG. 12 schematically shows an example of a batch-type heat treatment apparatus used in the present invention. In this device,
First, after the liquid is sprayed on the left side of the drawing, the transfer container 8 is transferred to the right side of the drawing by the slide device 39 together with the hearth floor, and the hearth 38 is transferred upward to be brought into close contact with the furnace wall to allow air flow. The raw material is heat treated below.

[0046]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Example 1 Three 213 kg of No. 3 water glass (No. 3K, made by Osaka Silica Co., Ltd.)
Charge in a 00 liter stirring tank and stir at room temperature with 48% N
61 kg of aOH solution (manufactured by Tosoh Corporation) and Ca (OH)
₂ (manufactured by Tosa Lime Company) 26 kg was added. After stirring for 3 hours, 300 kg of the white turbid slurry produced and spray-dried as it is (manufactured by Niro Japan, tower diameter 3.0 m, tower height 5.6).
m), and dried under the conditions of a blast temperature of 260 ° C. and an exhaust air temperature of 120 ° C. As a result, 118 kg of dry powder having an average particle diameter of 155 μm and a bulk specific gravity of 0.7 g / cc was obtained.

17 kg of this dry powder was charged into a bucket (500 × 500 × 200 mm, made of SUS310S) which was a container for transportation, and 25 g of a cloudy slurry was placed on the surface of the powder layer using a two-fluid nozzle (made by Spraying System). Sprayed. This application rate corresponds to 100 g / m ² .
This is a hot air circulation furnace (manufactured by Motoyama, furnace size 600 x 6
(00 × 600 mm) and heated at 600 ° C. for 10 hours (corresponding to aspect f). The air velocity in the furnace at this time was about 2 m / s in the vicinity of the surface of the stationary powder layer. After heat treatment, the product weight obtained was 13.5 kg. Further, no scattering of powder was observed in the furnace.

This product was analyzed by an X-ray diffractometer and was found to have crystallized silicate compound Na ₂ O.1.5SiO ₂
It was 0.5 CaO and the water content was 0% by weight. In addition, the water content was obtained from the ignition raw material at 700 ° C./1 hr,
The average particle size is a value of cumulative 50% by weight of a vibrating sieve, and the bulk specific gravity is a value measured by a 100 ml graduated cylinder without tapping.

Example 2 The same dry powder as in Example 1 was heat-treated with a roller hearth kiln (corresponding to embodiment d). Inner dimensions of roller hearth kiln are width 600mm, height 200mm, length 500
A combustion heating system was used as the heating means at 0 mm. The bucket, which is a container for transportation, is made of SUS310S and has a size of 400 × 400 × 100 mm.

9 kg per bucket was charged with the raw material powder using a screw feeder, and the bucket was conveyed at a frequency of 2 pieces / hour. At that time, the feeding speed of the feeder is 7
It is adjusted to 50 g / min and is controlled so as to be driven intermittently in conjunction with the conveyance of the bucket. While the bucket is conveyed by the roller conveyor at a speed of 1000 mm / hour, the tip of the bucket is below the cutout portion of the feeder. It is set to start the feeder when it reaches, stop the feeder when the last part of the bucket reaches below the cutout part of the feeder, and wait until the next bucket is conveyed.

The bucket to which the raw materials are supplied is conveyed by a roller conveyor at a speed of 1000 mm / hour and is conveyed under the spray nozzle. The spray nozzle is a two-fluid nozzle,
3 g / min of water was sprayed in the form of mist, and when it passed under this, about 2 on the surface of the stationary powder layer in the bucket.
It is adjusted so that 00 g / m ² of water is sprayed.
The bucket sprinkled with water is 50 by a roller conveyor.
It is conveyed in the heating furnace at a speed of 0 mm / hour and heat-treated.

The heat treatment temperature is 660 ° C., and the replacement air for removing the steam generated in the heating furnace is 10 Nm ³ /
We are supplying at the speed of time. At this time, the air velocity in the heating furnace was about 1.5 m / s near the surface of the stationary powder layer.

The heat-treated bucket is conveyed to a cooling device by a roller conveyor, cooled for 2 hours, and then inverted.
The heat-treated product is extracted from the bucket through the extraction device, and the emptied bucket is conveyed to the feeder section by the roller conveyor.

The above treatment cycle was continuously performed for 6.5 hours to obtain about 95 kg of a product. After the heat treatment, no scattering of powder was observed in the furnace, and the properties of the obtained product were the same as in Example 1.

Comparative Example 1 Heat treatment was performed under the same conditions as in Example 1 except that the liquid was not sprayed. After the heat treatment, the properties of the obtained product are shown in Example 1.
Same as the above, but adhesion of powder that turned yellow on the inner wall of the furnace was observed.

Example 3 2 kg of zinc carbonate powder (manufactured by Wako Pure Chemical Industries, Ltd.) is a bucket (300 × 250 × 80 mm, SUS304) which is a container for transportation.
8 g of water was sprayed on the surface of the powder layer using a two-fluid nozzle (manufactured by Spraying System Co., Ltd.). This application rate corresponds to 100 g / m ² . This is a hot air circulation furnace (manufactured by Motoyama Co., furnace size 600 x 600 x 600 m
m) and heated at 350 ° C. for 20 hours (corresponding to aspect f). The air velocity in the furnace at this time was about 2 m / s in the vicinity of the surface of the stationary powder layer. After the heat treatment, the product weight obtained was 1.4 kg, and when analyzed by an X-ray diffractometer, ZnO
Met. Further, no scattering of powder was observed in the furnace.

The following is a further description of the embodiments of the present invention. (1) In a method of heat-treating a stationary powder layer under an air flow, the method is a heat treatment method in which a liquid is sprayed on the surface of a stationary powder layer that is a raw material and then heat treated, and the bulk density of the raw material powder is 0.01 A heat treatment method of about 2.0 g / cc. (2) A spraying device for spraying a liquid on the surface of the stationary powder layer held in a container for supplying raw materials, a gas inlet and outlet, and a heating means arranged to heat the inside A heat treatment apparatus comprising a heating furnace, capable of supplying a raw material powder to a carrying container to form a stationary powder layer, spraying a liquid on the surface thereof, and heat-treating the raw material in the heating furnace. (3) A spraying device for spraying a liquid on the surface of a stationary powder layer held in a container for feeding raw materials, a gas inlet and outlet, and a heating means arranged to heat the inside are provided. A heating furnace and a transfer device for transferring the transfer container into the heating furnace are provided, the raw material powder is supplied to the transfer container to form a stationary powder layer, and a liquid is sprayed on the surface of the heating furnace. A heat treatment apparatus capable of heat-treating a raw material by transporting a transport container inside. (4) A spraying device for spraying a liquid onto the surface of a stationary powder layer held in a container for supplying raw materials, a gas inlet / outlet, an inlet / outlet of a container for transporting, and the inside for heating. A heating furnace having a heating means arranged, and a transfer device for passing a transfer container in the heating furnace, the raw material powder is continuously supplied to the transfer container to form a stationary powder layer, A heat treatment apparatus capable of heat-treating a raw material while spraying a liquid on the surface and transporting a transport container in the heating furnace. (5) A heating furnace having a gas inlet and outlet, a raw material supply port and a product discharge port, a spray liquid supply port, and heating means arranged to heat the inside, and a heating furnace installed in the heating furnace. A transporting device in which a plurality of transporting containers are connected to an endless power transmission member, and a spraying device for spraying a liquid on the surface of a stationary powder layer held in the transporting container, and circulating the power transmission member A heat treatment apparatus capable of heat-treating a raw material by feeding the raw material powder to the transporting container while driving to convey the transporting container to form a stationary powder layer, and spraying a liquid on the surface of the powder layer. (6) A spraying device for spraying a liquid on the surface of the stationary powder layer held on the conveyor belt to which the raw material is supplied, and a gas inlet and outlet, a conveyor belt inlet and outlet, and the inside thereof to be heated. A heating furnace having a heating means provided,
The heating furnace was equipped with a transfer device for passing the transfer belt, and the raw material powder was supplied to the transfer belt while the transfer belt was circulated to form a stationary powder layer, and a liquid was sprayed on the surface. , A heat treatment apparatus capable of heat treating raw materials.

[0059]

According to the heat treatment method and heat treatment apparatus of the present invention, it is possible to perform heat treatment while preventing the powder from scattering in the heat treatment apparatus. Further, by connecting and circulating a plurality of transport containers or driving the transport belt in a circulating manner, it is possible to perform the heat treatment continuously in an industrially advantageous manner.

[Brief description of drawings]

FIG. 1 schematically shows an example of a liquid spraying method according to the present invention, in which an upper view is a perspective view and a lower view is a plan view.

FIG. 2 is a longitudinal sectional view showing an example of a heat treatment apparatus used in the present invention.

FIG. 3 is a longitudinal sectional view showing an example of a heat treatment apparatus used in the present invention.

FIG. 4 is a longitudinal sectional view showing an example of a heat treatment apparatus used in the present invention.

FIG. 5 is a perspective view showing the form of connection between the bucket and the chain of the heat treatment apparatus of FIG. 3 and the like. The upper part shows the connecting part between the bucket and the chain, and the lower part shows the chain drive gear. A peripheral part is shown.

FIG. 6 is a plan view showing an example of a heat treatment apparatus used in the present invention.

7 is a cross-sectional view taken along line XX 'of the heat treatment apparatus of FIG.

8 is a cross-sectional view of the heat treatment apparatus of FIG. 6 taken along the line YY '.

FIG. 9 is a longitudinal sectional view showing an example of a heat treatment apparatus used in the present invention.

FIG. 10 shows an example of a rotary blade in a heat treatment apparatus used in the present invention.

FIG. 11 shows an example of a transport container in the heat treatment apparatus used in the present invention.

FIG. 12 is a schematic diagram showing an example of a batch-type heat treatment apparatus used in the present invention.

[Explanation of symbols]

 1 Transport means 2 Raw material 3 Heating means 4 Gas inlet 5 Gas outlet 6 Raw material supply port 6'Transport container inlet 7 Product discharge port 7'Transport container outlet 8 Transport container 10 Heating furnace 11 Raw material storage tank 12 raw material feeder 13 thermocouple 14 heat insulating material 15 product storage tank 19 power transmission member (chain) 20 drive shaft 21 belt drive gear 22 drive motor 23 rotary blade 24 bottom plate 25 product 26 chain 27 chain tension adjustment gear 28 transfer / reversal Means 29 Support roller 30 Drive roller 31 Conveying means 32 Door 33 Layer thickness control plate 34 Spray nozzle 35 Liquid feed pump 36 Spray liquid storage tank 37 Spray liquid 38 Hearth 39 Sliding device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikihiro Yamanaka 1334 Minato Minato, Wakayama City Kao Research Institute

Claims (8)

[Claims] 1. A method for heat-treating a stationary powder layer under an air stream, which comprises heat-treating after spraying a liquid on the surface of the stationary powder layer as a raw material. 2. The heat treatment method according to claim 1, wherein the liquid sprayed on the surface of the stationary powder layer is water. 3. The heat treatment method according to claim 1, wherein the liquid sprayed on the surface of the stationary powder layer is a solution or suspension containing the same powder component as that of the stationary powder layer. 4. The air velocity in the vicinity of the surface of the stationary powder layer in the heat treatment apparatus is 0.1 m / s to 50 m / s.
The heat treatment method according to any one of to 3. 5. A spraying device for spraying a liquid onto the surface of a stationary powder layer held in a transport container for supplying raw materials, a gas inlet and outlet, a transport container inlet and outlet, and the inside thereof are heated. A heating furnace having heating means arranged so as to arrange a roller conveyor having a driving roller endlessly or in such a manner that both ends of the roller conveyor are close to each other, and a conveying device part of which is arranged in the heating furnace. After transporting the transport container to the product discharge position and inverting it, the transport container is transported by rotating the drive roller using a heat treatment device equipped with a transport / reversal device that transports the transport container onto the transport device again. The heat treatment method according to any one of claims 1 to 4, wherein the raw material powder is supplied to a conveying container while being circulated to form a static powder layer, and a liquid is sprayed on the surface of the raw material powder to heat treat the raw material. 6. The heat-treated product produced is of the general formula xM ₂ O.
ySiO ₂ · zM′O (provided that M represents Na and / or K, M ′ represents Ca and / or Mg, and y / x = 0.
5 to 3.5 and z / x = 0 to 1.0. ) The heat treatment method according to any one of claims 1 to 5. 7. A spraying device for spraying a liquid onto the surface of a stationary powder layer held in a transport container for supplying raw materials, a gas inlet and outlet, a transport container inlet and outlet, and the inside thereof are heated. A heating furnace having heating means arranged so that a plurality of carrying containers are connected to the endless power transmission member, and a part of the carrying container is arranged to pass through the heating furnace. It is possible to heat-treat the raw material by supplying the raw material powder to the transport container while forming a stationary powder layer by spraying a liquid on the surface of the raw material powder while transporting the power transmission member while transporting the transport container. Heat treatment equipment. 8. A spraying device for spraying a liquid on the surface of a stationary powder layer held in a carrier container for supplying raw materials, a gas inlet / outlet, a carrier container inlet / outlet, and heating the inside. A heating furnace having heating means arranged so as to arrange a roller conveyor having a driving roller endlessly or in such a manner that both ends of the roller conveyor are close to each other, and a conveying device part of which is arranged in the heating furnace. It has a transfer / reversal device that transfers the transfer container to the product discharge position and reverses it, and then transfers the transfer container onto the transfer device again. A heat treatment apparatus capable of supplying raw material powder to a container for transportation to form a stationary powder layer, spraying a liquid on the surface thereof, and heat treating the raw material.