JP2017035665A - Spray device, spray-drying granulating device and manufacturing method for granulated powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spray device capable of manufacturing granulated powder with high production efficiency satisfying both of a production speed and a collection rate by drying sprayed slurry, and a spray-drying granulating device capable of manufacturing the granulated powder with the high production efficiency and a manufacturing method for the granulated powder.SOLUTION: A spray device 2 includes: a lower circular plate 231 (substrate) provided in a rotatable manner with a rotation axis as a center; an upper circular plate 232; a plurality of pins 233 being disposed along a circumference of a circle drawn by the lower circular plate 231 when it rotates at a top surface (one surface) side of the lower circular plate 231 and having axes disposed in a direction intersecting with a top surface of the lower circular plate 231; and discharge nozzles 24 being provided at the top surface side of the lower circular plate 231 and closer to a rotation axis O side than the plurality of pins 233 and comprising three or more discharge ports 243 capable of discharging slurry in a direction parallel to the circle drawn by the lower circular plate 231 when it rotates.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a spray device, a spray-drying granulator, and a method for producing a granulated powder.

  As one of the methods for producing the granulated powder, there is a method (spray drying method) of spray drying a slurry in which a powder, a dispersion medium and an additive are mixed. In the spray drying method, a spray dryer (spray drying granulator) including a spraying device for spraying slurry and a drying means for drying the sprayed slurry is used.

  Among these, as a spraying device, for example, a device including a rotary disk that is driven to rotate at high speed and a nozzle that supplies slurry to the rotary disk is known (for example, see Patent Document 1).

  In such a spraying device, when the slurry comes into contact with the rotating rotary disk, the slurry can be sprayed by the centrifugal force of the rotary disk. A granulated powder can be produced by drying the sprayed slurry.

JP 2002-58981 A

  However, the spray device described in Patent Document 1 has a problem that the recovery rate of the granulated powder decreases as the amount of slurry supplied to the nozzle is increased. For this reason, the production efficiency of the granulated powder is not sufficiently increased.

  An object of the present invention is to provide a spraying apparatus capable of producing a granulated powder with high production efficiency that achieves both a production rate and a recovery rate by drying the sprayed slurry, and a granulated powder with high production efficiency. An object of the present invention is to provide a spray-drying granulator and a granulated powder manufacturing method that can be manufactured.

Such an object is achieved by the present invention described below.
The spray device of the present invention includes a substrate that is rotatably provided around a rotation axis;
A plurality of pins disposed on one surface side of the substrate along a circumference of a circle drawn when the substrate rotates, and arranged in a direction in which an axis intersects the one surface;
A discharge nozzle that is provided on one surface side of the substrate and closer to the rotating shaft than the plurality of pins, and includes three or more discharge ports capable of discharging slurry in a direction parallel to the circle;
It is characterized by having.

  Thus, by drying the sprayed slurry, it is possible to obtain a spraying device capable of producing a granulated powder with high production efficiency while achieving both a production rate and a recovery rate.

  In the spraying apparatus of the present invention, it is preferable that the discharge nozzle discharges the slurry at a supply linear velocity of 5 cm / second or more per one discharge port.

  Thereby, since the slurry can be discharged from the discharge port with sufficient momentum, the probability that the discharged slurry directly hits the pin can be particularly increased. As a result, even when the supply amount of the slurry supplied to the discharge nozzle is increased, the slurry can be sufficiently refined, and the recovery rate of the granulated powder can be particularly increased.

  In the spray device of the present invention, it is preferable that a distance between the discharge port and the pin is 0.5 cm or more and 3 cm or less.

  Thereby, the slurry discharged from the discharge port can be miniaturized, and the generated droplets can be scattered outside the substrate by centrifugal force. As a result, the recovery rate of the granulated powder can be particularly increased.

  In the spray device of the present invention, it is preferable that the diameter of the discharge port is 1 mm or more and 6 mm or less.

  Thereby, it is possible to prevent the discharge port from being clogged with the slurry, and to suppress the slurry supply linear velocity from becoming too small.

  In the spraying apparatus of the present invention, the constituent material of the discharge nozzle is preferably a metal material.

  Thereby, the abrasion resistance of the discharge nozzle can be enhanced. As a result, the life of the discharge nozzle can be extended.

  In the spray device of the present invention, it is preferable that the plurality of pins are arranged at equal intervals along the circumference.

  Thereby, when slurry is simultaneously discharged from a plurality of discharge ports while rotating a plurality of pins, the frequency at which the discharged slurry collides with the pins can be made uniform between the discharge ports. As a result, a granulated powder having a uniform particle size (narrow particle size distribution) can be finally produced.

The spray-drying granulator of the present invention includes the spray device of the present invention,
Slurry supply means for supplying slurry to the spraying device;
Drying means for drying droplets of the slurry formed by the spraying device;
It is characterized by having.

  As a result, a spray-drying granulator capable of producing a granulated powder with high production efficiency while achieving both a production rate and a recovery rate can be obtained.

The method for producing the granulated powder of the present invention includes a substrate that is rotatably provided around a rotation axis,
A plurality of pins disposed on one surface side of the substrate along a circumference of a circle drawn when the substrate rotates, and arranged in a direction in which an axis intersects the one surface;
A discharge nozzle that is provided on one surface side of the substrate and closer to the rotating shaft than the plurality of pins, and includes three or more discharge ports capable of discharging slurry;
Providing a spraying device having:
Forming a droplet by discharging slurry from the discharge port toward the pin and applying the slurry to the pin in a state where the substrate and the plurality of pins are rotated around the rotation axis;
Drying the droplets to obtain a granulated powder;
It is characterized by having.

  Thereby, it is possible to produce a granulated powder with a high production efficiency while achieving both a production rate and a recovery rate.

It is a longitudinal cross-sectional view which shows embodiment of the spray-drying granulation apparatus of this invention. It is a perspective view which expands and shows a spraying apparatus among the spray-drying granulation apparatuses shown in FIG. It is a top view of the spraying apparatus shown in FIG. FIG. 4 is a sectional view taken along line AA in FIG. 3. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is a top view which shows the 1st modification of the discharge nozzle shown in FIG. It is a top view which shows the 2nd modification of the discharge nozzle shown in FIG. It is process drawing for demonstrating embodiment of the manufacturing method of the granulated powder of this invention. It is a top view of the spraying apparatus used in Comparative Example 1. It is CC sectional view taken on the line of FIG.

  Hereinafter, the spray device, spray-drying granulator, and granulated powder manufacturing method of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<Spray drying granulator>
First, an embodiment of the spray drying granulation apparatus of the present invention will be described.

  FIG. 1 is a longitudinal sectional view showing an embodiment of the spray-drying granulator of the present invention, and FIG. 2 is an enlarged perspective view showing the spraying device in the spray-drying granulator shown in FIG. 3 is a top view of the spray device shown in FIG. 2, FIG. 4 is a cross-sectional view taken along line AA in FIG. 3, and FIG. 5 is a cross-sectional view taken along line BB in FIG. In the following description, for the sake of convenience of explanation, the upper side of FIGS.

  A spray-drying granulator 1 shown in FIG. 1 includes a sprayer 2 (an embodiment of the sprayer of the present invention) that sprays a slurry 9 and a slurry supply unit 3 (slurry supply unit) that supplies the slurry 9 to the sprayer 2. A drying unit 4 (drying means) that dries the droplets 91 of the slurry 9 formed by the spray device 2, a chamber 5 that houses the spray device 2 and the like, an exhaust unit 6 that exhausts the inside of the chamber 5, and a chamber And a collection unit 7 that collects the granulated powder produced in the inside. Such a spray-drying granulator 1 granulates inorganic powder by drying the slurry 9 while spraying it, and produces granulated powder. Hereinafter, each part will be described.

  First, prior to the description of the spray drying granulator 1, the slurry 9 will be described. The slurry 9 is a suspension containing an inorganic powder and an organic binder.

  Among these, the inorganic powder is not particularly limited and may be any kind of powder. As the constituent material of the inorganic powder, for example, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Pd, Ag, In, Sn, Ta, In addition to a single metal such as W or a metal material such as an alloy containing at least one of these, various ceramic materials can be used.

  As more specific metal materials, for example, stainless steel, low carbon steel, carbon steel, heat resistant steel, die steel, high speed tool steel, Fe—Ni alloy, Fe—Ni—Co alloy and the like can be cited. Among these, as stainless steel, SUS304, SUS316, SUS317, SUS329, SUS410, SUS430, SUS440, SUS630, etc. are mentioned, for example.

  The average particle size of the inorganic powder is preferably 1 μm or more and 30 μm or less, more preferably 2 μm or more and 20 μm or less, and further preferably 3 μm or more and 10 μm or less. Since the inorganic powder having such a particle size has sufficiently high fluidity of the granulated powder while avoiding a decrease in compressibility at the time of molding, it is finally possible to produce a sufficiently dense sintered body. Become.

  When the average particle size is less than the lower limit, the inorganic powder is likely to aggregate before granulation, the content of the inorganic powder varies among the particles of the granulated powder, and the compressibility during molding is There is a risk of a significant decrease. On the other hand, when the average particle diameter exceeds the upper limit, when formed, the gap between the particles of the granulated powder becomes too large, and there is a possibility that the final sintered body will not be sufficiently densified. is there.

  In addition, the average particle size of the inorganic powder is the particle size when the accumulation of mass-based particle sizes is 50% from the small diameter side in the particle size distribution obtained by the laser diffraction method.

  Such an inorganic powder may be produced by any method, for example, by an atomization method (water atomization method, gas atomization method, high-speed rotating water atomization method, etc.), reduction method, carbonyl method, pulverization method, or the like. What was manufactured can be used.

  On the other hand, examples of the organic binder include polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer, acrylic resins such as polymethyl methacrylate and polybutyl methacrylate, styrene resins such as polystyrene, polyvinyl chloride, and polyvinyl chloride. Various resins such as polyesters such as vinylidene, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyether, polyvinyl alcohol, polyvinyl pyrrolidone or copolymers thereof, waxes, alcohols, higher fatty acids, fatty acid metals, higher fatty acid esters, Examples include higher fatty acid amides, nonionic surfactants, silicone-based lubricants, etc., and one or a mixture of two or more of these is used.

  Among these, the organic binder preferably contains polyvinyl alcohol or a derivative thereof (hereinafter simply referred to as “polyvinyl alcohol”). Since polyvinyl alcohol has high binding properties, it is possible to efficiently form a granulated powder even in a relatively small amount. In addition, since it has high thermal decomposability, it can be reliably decomposed and removed in a short time during degreasing and firing.

  As the polyvinyl alcohol, those having a weight average molecular weight of about 2000 to 200000 are preferably used, and those having a weight average molecular weight of about 5000 to 150,000 are more preferably used. Such polyvinyl alcohol is most suitable as an organic binder in terms of viscosity and thermal decomposability. Specifically, the binding property between the particles of the inorganic powder at the time of granulation, the disintegration property at the time of molding the granulated powder, the shape retention of the molded product, and the like can be made side by side. As a result, a sintered body excellent in density and dimensional accuracy can be obtained.

  In addition, the derivative | guide_body of polyvinyl alcohol means what substituted the hydrogen atom couple | bonded with the carbon atom with various functional groups, and an alkyl group, a silyl group, an acrylate group etc. are mentioned as a functional group, for example.

  The spraying device 2 is a device that sprays the slurry 9 supplied from the slurry supply unit 3 into the chamber 5. Specifically, the spray device 2 discharges the slurry 9 toward the drive unit 21, the rotating shaft 22 rotated by the drive unit 21, the spray plate 23 fixed to the lower end of the rotary shaft 22, and the spray plate 23. And a discharge nozzle 24. The slurry 9 is refined into droplets 91 by the spray device 2. And the granulated powder is produced | generated by drying the droplet 91. FIG. The spray device 2 will be described in detail later.

  The slurry supply unit 3 includes a slurry tank 31 that stores the slurry 9, and a pipe 32 that sends the slurry 9 stored in the slurry tank 31 to the spraying device 2. Further, the slurry supply unit 3 includes a pump (not shown), and can supply the slurry 9 to the spray device 2 at a high pressure.

  The drying unit 4 includes a hot air generator 41 and a pipe 42 that sends the hot air generated by the hot air generator 41 into the chamber 5. The hot air generated in the drying unit 4 dries the droplet 91 in the chamber 5 in a short time. Thereby, while the solvent in the droplet 91 volatilizes, the particles of the inorganic powder are bound together via the organic binder, and the granulated powder can be manufactured.

  The chamber 5 is a container having an internal space in which droplets 91 are sprayed. Specifically, a drying chamber 51 in which droplets 91 are sprayed and dried and a duct 52 for lowering hot air generated in the drying unit 4 toward the drying chamber 51 are provided.

  The shape of the drying chamber 51 is not particularly limited, but in the present embodiment, the drying chamber 51 has a cylindrical shape and the lower portion has a conical shape.

  The duct 52 is provided so as to surround the spray device 2, and the hot air can be lowered so as to be substantially parallel to the rotation axis O of the rotary shaft 22 of the spray device 2. Thereby, the droplet 91 sprayed by the spraying apparatus 2 can be dried quickly.

  The exhaust unit 6 includes a pipe 61 extending from the chamber 5 and a pump (not shown). One end of the pipe 61 is disposed in the middle portion of the chamber 5 in the vertical direction. Thereby, the exhaust unit 6 can exhaust the inside of the chamber 5 together with the fine powder floating in the chamber 5.

  The collection unit 7 is provided below the chamber 5, and includes a granulated powder produced in the chamber 5, in addition to the pipe 71, a valve (not shown) for opening and closing the pipe 71. The granulated powder produced in the chamber 5 accumulates below the chamber 5 while falling naturally. And it can collect | recover from the collection | recovery part 7. FIG.

<Spraying device>
Next, an embodiment of the spray device of the present invention will be described in detail.

  As shown in FIG. 1, the spray device 2 includes a drive unit 21, a rotary shaft 22, and a spray board 23. Moreover, the spraying apparatus 2 is further provided with the discharge nozzle 24, as shown in FIG.

  The drive unit 21 includes a mechanism that rotates the rotary shaft 22. Specifically, a drive source such as a drive motor may be provided in the drive unit 21 illustrated in FIG. 1, and the power of the drive motor provided outside the drive unit 21 is transmitted via a belt or the like. The rotation shaft 22 may be driven to rotate by being transmitted to the drive unit 21.

  The rotation shaft 22 is arranged so that the rotation axis O thereof is parallel to the vertical direction, the upper end is connected to the drive unit 21, and the lower end is connected to the spray board 23. Thereby, the driving force in the drive part 21 is transmitted to the spray board 23 via the rotating shaft 22, and the spray board 23 can be rotationally driven.

  The spraying plate 23 includes a lower disc 231 (substrate) that is circular in a plan view from the vertical direction, an upper disc 232 that is annular in a plan view, and a lower disc 231 and an upper disc 232. And a plurality of pins 233 for connecting the two.

  Among these, the center of the lower disk 231 is fixed to the lower end of the rotary shaft 22. Thereby, the lower disk 231 rotates with the rotation of the rotating shaft 22. Further, the rotation axis O of the rotation shaft 22 is orthogonal to the upper surface (one surface) of the lower disk 231. For this reason, when the rotating shaft 22 rotates, its rotating surface is parallel to the upper surface of the lower disk 231. Such a positional relationship is not particularly limited. For example, the rotation axis O may not be orthogonal to the upper surface of the lower disk 231.

  The upper disk 232 is provided above the lower disk 231. Further, the ring of the upper disk 232 is arranged so as to draw a concentric circle with respect to the rotation axis O of the rotation shaft 22. Thereby, the upper disk 232 is separated from the rotating shaft 22.

  A discharge nozzle 24 is inserted between the upper disk 232 and the rotary shaft 22. As a result, the tip of the discharge nozzle 24 can be disposed inside the spray plate 23 without interfering with the spray plate 23. That is, since the spray platen 23 and the discharge nozzle 24 are structurally separated from each other, when the spray platen 23 is rotating, the discharge nozzle 24 can continue to maintain the posture shown in FIG. 3, for example. .

  The shape of each pin 233 is not particularly limited, and examples thereof include a conical shape, a conical shape, a prismatic shape, and a cylindrical shape. In this embodiment, the pin 233 has a cylindrical shape. Each pin 233 is arranged (stands up) so that the axis of the pin 233 is orthogonal to the upper surface of the lower disk 231.

  Moreover, each pin 233 is arrange | positioned along the circumference of the circle drawn when the lower disc 231 rotates. That is, since the lower disk 231 has a circular shape in plan view and the center thereof coincides with the rotation axis O, each pin 233 is disposed along the outer edge of the lower disk 231.

  Further, each pin 233 connects the lower disk 231 and the upper disk 232. In other words, the interval between the pins 233 is fixed by the lower disk 231 and the upper disk 232. In addition, the upper surface of the lower disk 231 and the lower surface of the upper disk 232 are held by the pins 233 so as to be parallel to each other.

  The discharge nozzle 24 includes a vertical nozzle 241 extending in the vertical direction, a horizontal nozzle 242 connected to the lower end of the vertical nozzle 241 and extending in the horizontal direction, and a discharge port 243 that is an opening of the horizontal nozzle 242. It is out. The discharge nozzle 24 is connected to a pipe 32 of the slurry supply unit 3 shown in FIG. Thereby, the slurry 9 stored in the slurry tank 31 is discharged from the discharge port 243 through the pipe 32, the vertical nozzle 241 and the horizontal nozzle 242 in order.

  The slurry 9 discharged from the discharge port 243 is sprayed by the spray board 23 and becomes droplets 91. And the granulated powder is manufactured by drying this droplet 91. FIG.

  By the way, in such a discharge nozzle 24, it is desired to increase the production rate of the granulated powder by increasing the supply amount of the slurry 9 supplied to the discharge nozzle 24 per unit time. However, conventionally, when the discharge amount in the discharge nozzle 24 is increased, there is a problem that the recovery rate (granulation yield) of the granulated powder decreases.

  Therefore, the present inventor has conducted intensive studies on means for solving such problems. And when the discharge amount of the slurry 9 was increased, the conventional spraying apparatus discovered that the slurry 9 was not able to be refined | miniaturized enough. In addition, the discharge port 243 is configured so that the slurry 9 is discharged in a direction parallel to a circle drawn when the lower disk 231 rotates, and three or more discharge ports 243 (this embodiment) The present invention has been completed by finding that the above-mentioned problems can be solved by satisfying both of the above.

  That is, the discharge nozzle 24 according to the present embodiment is provided on the upper surface side of the lower disk 231 and on the rotation shaft 22 side (rotation axis O side) from each pin 233 (FIGS. 3 and 4). reference). Further, the discharge port 243 can discharge the slurry 9 in a direction parallel to a circle drawn when the lower disk 231 rotates. That is, since the upper surface of the lower disk 231 according to the present embodiment is parallel to the rotation surface, the discharge port 243 discharges the slurry 9 in a direction parallel to the upper surface of the lower disk 231 (see FIG. 5). .

  The slurry 9 discharged from the discharge port 243 has a high probability of directly hitting each pin 233 without hitting the lower disk 231 or the upper disk 232. As described above, the pins 233 are arranged along the outer edge of the lower disk 231. Therefore, each pin 233 is rotationally driven together with the lower disk 231 and the slurry 9 is discharged from the discharge port 243 in this state. At this time, the discharged slurry 9 strikes each pin 233 and is refined (sprayed) into a large number of droplets 91 by the impact force at that time and the force by which the pin 233 rotates. Then, the formed many droplets 91 are scattered to the outside of the rotation surface by centrifugal force. A granulated powder is produced by drying the droplets 91 scattered in this manner.

  At this time, if the spray board 23 is provided with three or more discharge ports 243, even if the supply amount of the slurry 9 supplied to the discharge nozzle 24 is increased, the spray plate 23 is discharged from one discharge port 243 per unit time. The amount of slurry 9 to be retained is sufficiently suppressed. For this reason, by dividing the supplied slurry 9 with the rotating pin 233, sufficient miniaturization can be achieved without unevenness. That is, it is possible to minimize the amount of the slurry 9 that is discharged from the spray board 23 without being miniaturized. As a result, the ratio (granulated powder recovery rate) recovered as the granulated powder can be increased. Therefore, both the production rate and the recovery rate of the granulated powder can be achieved, and high production efficiency can be realized.

  When the discharge port 243 is not parallel to the upper surface of the lower disk 231, the probability that the slurry 9 discharged from the discharge port 243 hits the lower disk 231 or the upper disk 232 increases. When the slurry 9 hits the lower disk 231 and the upper disk 232, the slurry 9 easily adheres to the lower disk 231 and the upper disk 232. For this reason, the rate at which the slurry 9 is divided by the pins 233 is reduced. As a result, the recovery rate as a granulated powder will fall.

  When the number of discharge ports 243 is two or less, when the supply amount of the slurry 9 supplied to the discharge nozzle 24 per unit time is increased, the slurry 9 is discharged as it is from the spray plate 23 without being completely miniaturized. A large amount of the slurry 9 is generated. For this reason, the recovery rate as granulated powder will fall.

  Further, the discharge nozzle 24 according to the present embodiment includes two vertical nozzles 241, a horizontal nozzle 242 connected to the lower end of each vertical nozzle 241, and two discharge ports 243 provided for each horizontal nozzle 242. , Including.

  Among these, the vertical nozzle 241 and the horizontal nozzle 242 are each formed of a tubular body, and an intermediate portion in the longitudinal direction of the horizontal nozzle 242 and a lower end of the vertical nozzle 241 are connected. In the connection part, the insides of the tubular bodies can circulate with each other. And the discharge outlet 243 is located in the both ends of the longitudinal direction of each horizontal nozzle 242. FIG. Therefore, a total of four discharge ports 243 are provided in the entire spray device 2.

  The number of discharge ports 243 in the spray device 2 is not particularly limited as long as it is 3 or more, but is preferably 4 or more and 30 or less, and more preferably 4 or more and 12 or less. Thereby, refinement | miniaturization of the slurry 9 is optimized and the collection | recovery rate of granulated powder can be raised especially. If the number of discharge ports 243 exceeds the upper limit, depending on the size of the spray plate 23, the distance between adjacent discharge ports 243 becomes very short. For this reason, the slurries 9 discharged from the adjacent discharge ports 243 may interfere with each other, and the progress of miniaturization may be hindered.

  As described above, the discharge direction of the slurry 9 discharged from the discharge port 243 is parallel to the upper surface of the lower disk 231. At this time, “parallel” refers to the discharge direction of the slurry 9 and the lower circle. This includes a state where the angle formed by the upper surface of the plate 231 is 10 ° or less.

  In this embodiment, each pin 233 is arranged so that the axis of the pin 233 is orthogonal to the upper surface of the lower disk 231, but the axis of the pin 233 is orthogonal to the upper surface of the lower disk 231. It does not have to be. For example, the axis of the pin 233 may be inclined from the orthogonal state toward the center of the lower disk 231, may be inclined outward, or may be inclined along the circumference. In this case, the inclination angle from the normal line of the upper surface of the lower disk 231 is not particularly limited, but is preferably 30 ° or less.

  The discharge nozzle 24 is preferably detachable from the pipe 32. Thereby, even when the discharge nozzle 24 is worn out or the slurry 9 is clogged, it can be easily replaced with another discharge nozzle 24 or cleaned.

  In addition, an increase in the recovery rate of the granulated powder means that the amount of the slurry 9 that cannot be recovered is reduced.

  Examples of the slurry 9 that cannot be recovered include the slurry 9 attached to the inner wall surface of the chamber 5, the slurry 9 attached to the surface of the spray plate 23, and the slurry 9 clogged in the discharge nozzle 24. By reducing the amount of the slurry 9 that cannot be collected, labor and cost for cleaning the chamber 5 and the spray plate 23 can be reduced. From this point of view, the production efficiency of the granulated powder can be improved.

  Further, the supply linear velocity of the slurry 9 discharged from one discharge port 243 is preferably 5 cm / second or more, and more preferably 10 cm / second or more. Thereby, since the slurry 9 can be discharged from the discharge port 243 with sufficient momentum, the probability that the discharged slurry 9 directly hits the pin 233 can be particularly increased. As a result, even when the supply amount of the slurry 9 supplied to the discharge nozzle 24 per unit time is increased, the slurry 9 can be sufficiently refined, and the recovery rate of the granulated powder can be particularly increased.

Note that the supply linear velocity SLV [cm / sec] of the slurry 9 is that the supply amount of the slurry 9 per unit time in the entire discharge nozzle 24 is X [cm ³ / min], and the diameter of the discharge port 243 is Nr [cm]. Assuming that the number of discharge ports 243 included in the entire discharge nozzle 24 is n [pieces], the following equation is obtained.
SLV = (X / n) / [π × (Nr / 2) ² ] / 60

  Further, the diameter Nr of the discharge port 243 is not particularly limited, but is preferably 1 mm or more and 6 mm or less, and more preferably 2 mm or more and 5 mm or less. By setting the diameter Nr of the discharge port 243 within the above range, it is possible to prevent the discharge port 243 from being clogged with the slurry 9 and to suppress the supply linear velocity of the slurry 9 from becoming too small. If the diameter Nr of the discharge port 243 is less than the lower limit value, the discharge port 243 may be easily clogged depending on the viscosity of the slurry 9 or the like. On the other hand, when the diameter Nr of the discharge port 243 exceeds the upper limit value, depending on the size of the spray plate 23 and the like, the supply amount of the slurry 9 necessary for discharging the slurry 9 from one discharge port 243 with sufficient momentum is obtained. Become more. For this reason, there is a possibility that the total amount of the slurry 9 applied to the pin 233 within a unit time becomes too large and becomes saturated, making it difficult to make the slurry 9 finer.

  Further, the distance L1 (see FIG. 3) between the discharge port 243 and the pin 233 is not particularly limited, but is preferably 0.5 cm or more and 3 cm or less, and more preferably 1 cm or more and 2.5 cm or less. By setting the distance L1 between the discharge port 243 and the pin 233 within the above range, the slurry 9 discharged from the discharge port 243 is refined, and the generated droplet 91 is scattered outside the spray plate 23 by centrifugal force. Can be made. Therefore, the recovery rate of the granulated powder can be particularly increased. And since the quantity of the slurry 9 which cannot be collect | recovered can be reduced, the effort and cost concerning the cleaning operation | work of the chamber 5 or the spraying board 23 can be reduced. From this point of view, the production efficiency of the granulated powder can be improved.

  When the distance L1 between the discharge port 243 and the pin 233 is less than the lower limit value, the slurry 9 discharged from the discharge port 243 is about to be refined by the pin 233 depending on the rotation speed of the spray plate 23. There is a possibility that the probability of collision with 9 increases. At this time, the slurry 9 is likely to be clogged in the discharge port 243, and there is a possibility that the discharge of the slurry 9 is hindered. Moreover, since the flight speed of the slurry 9 reaches the pin 233 in a state where it does not drop much from the initial speed, the probability of not colliding with the pin 233 (passing through between the pins 233) is somewhat high, and the ratio that can be recovered as granulated powder And the probability of adhering to the inner wall surface of the chamber 5 may increase. On the other hand, if the distance L1 between the discharge port 243 and the pin 233 exceeds the upper limit value, depending on the rotational speed of the spray plate 23, the slurry 9 may rebound to the rotating shaft side after hitting the pin 233, and the granulated powder As a result, the amount of the slurry 9 that can be recovered may decrease. One reason for this is that when the flight speed of the slurry 9 is greatly reduced from the initial speed, it easily rebounds when it collides with the pin 233.

  The distance L1 between the discharge port 243 and the pin 233 is such that the center point of the discharge port 243 and the pin 233 are connected in the direction in which the discharge port 243 is open (the direction in which the discharge port 243 faces). The shortest distance between the possible circumferential CF.

  The distance L1 is preferably 5% or more and 30% or less of the diameter of the lower disc 231 and more preferably 10% or more and 25% or less. Also in this case, the slurry 9 discharged from the discharge port 243 can be refined, and the generated droplet 91 can be scattered outside the spray disc 23 by centrifugal force. Therefore, the recovery rate of the granulated powder can be particularly increased. And since the quantity of the slurry 9 which cannot be collect | recovered can be reduced, the effort and cost concerning the cleaning operation | work of the chamber 5 or the spraying board 23 can be reduced.

  Further, in the plan view, the arrangement of the plurality of discharge ports 243 is line symmetric with respect to a straight line passing through the rotation axis of the rotary shaft 22 as a symmetric axis, or point symmetric with respect to the rotation axis as a symmetric center. Preferably there is. Thereby, the behavior of refining the slurry 9 discharged from the discharge port 243 tends to be smooth, and the recovery rate of the granulated powder can be particularly increased. In other words, on the circumference where the pins 233 are arranged, it is possible to secure a certain interval between the slurries 9 discharged from the discharge ports 243. For this reason, the problem which arises, for example because the slurry 9 discharged from the adjacent discharge port 243 interferes with each other can be solved. As such a problem, for example, sufficient miniaturization cannot be achieved.

  Moreover, although the space | interval of pins 233 is not specifically limited, Preferably it is set as equal space | interval along the periphery mentioned above. Accordingly, when the slurry 9 is simultaneously discharged from the plurality of discharge ports 243 while rotating the plurality of pins 233, the frequency with which the discharged slurry 9 collides with the pins 233 is uniformed between the discharge ports 243. Can be achieved. For this reason, when the slurry 9 discharged from the discharge port 243 is refined by the pin 233, the variation in the diameter of the generated droplet 91 can be suppressed to be small. As a result, a granulated powder having a uniform particle size (narrow particle size distribution) can be finally produced.

  The outer diameters of the lower disk 231 and the upper disk 232 are not particularly limited, but are preferably about 3 cm to 40 cm.

  Moreover, the planar view shape of the lower disk 231 may be other shapes, for example, a polygon such as a hexagon or an octagon, or a circle other than a perfect circle such as an ellipse or an ellipse. Similarly, the shape of the upper disk 232 in plan view may be other shapes, for example, a polygonal ring such as a hexagon or an octagon, or a circular ring other than a perfect circle such as an ellipse or an ellipse. .

  On the other hand, the length of the pin 233 (the length in the direction connecting the lower disk 231 and the upper disk 232) is not particularly limited, but is preferably about 1 cm or more and 15 cm or less.

  The shape of the pin 233 may be a shape other than a cylinder, such as a prism, a cone, a pyramid, or the like.

  Further, the structure of the spray board 23 is not limited to the above. For example, the upper disk 232 may be provided as necessary, and may be omitted when the pins 233 can be supported only by the lower disk 231.

  Further, the lower disk 231, the upper disk 232, and the pin 233 may be different members, but may be integrated.

  In addition, it does not specifically limit as each constituent material of the lower disc 231, the upper disc 232, and the pin 233, Various metal materials, various ceramic materials, etc. are mentioned.

  Moreover, it does not specifically limit as a constituent material of the discharge nozzle 24, Various metal materials, various ceramic materials, various resin materials, etc. are mentioned.

  Of these, metal materials are preferably used. Since the metal material has a relatively high hardness, the wear resistance of the discharge nozzle 24 can be improved by using it as a constituent material of the discharge nozzle 24 with which the slurry 9 flowing at high speed comes into contact. As a result, the life of the discharge nozzle 24 can be extended. Moreover, since the diameter of the discharge port 243 is stabilized over a long period by suppressing the wear of the discharge nozzle 24, the particle diameter and the recovery rate of the granulated powder can be stably maintained over a long period.

Here, a modified example of the discharge nozzle 24 will be described.
FIG. 6 is a top view showing a first modification of the discharge nozzle 24 shown in FIG. In FIG. 6, for convenience of explanation, the rotating shaft 22 and the spray platen 23 are illustrated by broken lines. In FIG. 6, the pin 233 is not shown.

  The discharge nozzle 24 shown in FIG. 6 is the same as the discharge nozzle 24 shown in FIG. 3 except for the following matters.

  That is, the discharge nozzle 24 shown in FIG. 6 includes two vertical nozzles (not shown), a horizontal nozzle 242 connected to the lower end of each vertical nozzle, and three discharge ports provided for each horizontal nozzle 242. 243.

  And the discharge outlet 243 is provided in the both ends of the longitudinal direction of each horizontal nozzle 242, and an intermediate part. Accordingly, the total number of discharge ports 243 in the entire spray device 2 shown in FIG. 6 is six.

  Also in the spray device 2 including the discharge nozzle 24 according to such a modification, the same effect as the spray device 2 including the discharge nozzle 24 shown in FIG. 3 described above can be obtained.

  FIG. 7 is a top view showing a second modification of the discharge nozzle 24 shown in FIG. In FIG. 7, for convenience of explanation, the rotating shaft 22 and the spray platen 23 are illustrated by broken lines. In FIG. 7, the pin 233 is not shown.

  The discharge nozzle 24 shown in FIG. 7 is the same as the discharge nozzle 24 shown in FIG. 3 except for the following matters.

  That is, the discharge nozzle 24 shown in FIG. 7 includes two vertical nozzles (not shown), a horizontal nozzle 242 connected to the lower end of each vertical nozzle, and six discharge ports provided for each horizontal nozzle 242. 243.

  The discharge ports 243 are provided at both ends in the longitudinal direction of the horizontal nozzles 242 and at the other four locations. Accordingly, the total number of discharge ports 243 in the entire spray device 2 shown in FIG. 7 is twelve.

  Also in the spray device 2 including the discharge nozzle 24 according to such a modification, the same effect as the spray device 2 including the discharge nozzle 24 shown in FIG. 3 described above can be obtained.

<Method for producing granulated powder>
Next, an embodiment of a method for producing a granulated powder of the present invention will be described.

FIG. 8 is a process diagram for explaining an embodiment of the method for producing a granulated powder of the present invention.
The method for producing the granulated powder shown in FIG. 8 includes the step of preparing the spray-drying granulator 1 including the spray device 2 and the slurry 9 toward the pin 233 in a state where the spray disc 23 of the spray device 2 is rotated. Are ejected and applied to the pins 233 to form droplets 91, and the droplets 91 are dried to obtain granulated powder. Hereinafter, each step will be described.

  [1] First, the spray drying granulation apparatus 1 including the spraying apparatus 2 is prepared (step S1). At this time, the slurry 9 is stored in the slurry tank 31.

  The slurry 9 is a suspension containing inorganic powder, an organic binder, and various additives. Examples of the additive include a solvent (dispersion medium), a rust inhibitor, an antioxidant, a surfactant, and an antifoaming agent.

  In addition, it is preferable that the density | concentration of the inorganic powder in the slurry 9 is about 10 to 90 mass%, and it is more preferable that it is about 20 to 80 mass%.

  The content of the organic binder is preferably about 0.2 parts by mass or more and 10 parts by mass or less, and preferably about 0.3 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the inorganic powder. More preferably, it is 0.3 to 2 parts by mass.

  [2] Next, the rotary shaft 22 and the spray platen 23 are driven to rotate by the drive unit 21. Further, hot air is sent into the chamber 5 by the drying unit 4. Further, the inside of the chamber 5 is exhausted by the exhaust unit 6. In this state, the slurry 9 is discharged from the discharge port 243 of the discharge nozzle 24. At this time, the direction of the discharge port 243 is adjusted so that the discharged slurry 9 directly contacts the pin 233. For example, as described above, it is preferable to adjust the discharge direction of the slurry 9 so as to be parallel to the upper surface of the lower disk 231, but the discharge direction of the slurry 9 is slightly changed in consideration of the fall due to gravity. May be directed upward.

  The slurry 9 discharged from the discharge port 243 flies toward the outside through the inside of the spray board 23 and hits the rotating pin 233. Thereby, the slurry 9 is refined | miniaturized and disperse | distributes to the outer side of the spray board 23 as the droplet 91 (process S2).

  The number of revolutions of the spray platen 23 is appropriately set according to the intended particle size of the granulated powder, the concentration of the slurry 9, the temperature of the chamber 5, etc. As an example, it is 3000 times / min to 30000 times / min. It is preferable that it is about the following.

  [3] Next, the scattered droplets 91 are dried. Thereby, the granulated powder comprised by the granulated particle formed by binding | bonding the particles in inorganic powder is obtained (process S3). The produced granulated powder falls in the chamber 5 and can be discharged out of the chamber 5 by the recovery unit 7 and recovered.

  Among the granulated powders, those having a small particle diameter are discharged together when the chamber 5 is exhausted. For this reason, in the exhaust part 6, the granulated powder in exhaust can be filtered and collect | recovered.

  The temperature of the hot air sent into the chamber 5 is appropriately set according to the size of the chamber 5, the concentration of the slurry 9, etc. As an example, it is preferably about 100 ° C. or higher and 300 ° C. or lower, preferably 120 ° C. or higher and 250 ° C. It is more preferable that the temperature be about ℃ or less.

  As mentioned above, although the spraying apparatus of this invention, the spray-drying granulation apparatus, and the manufacturing method of granulated powder were demonstrated based on embodiment of illustration, this invention is not limited to these.

  For example, in the spray device and spray-drying granulator of the present invention, the configuration of each part according to the above embodiment can be replaced with any configuration that exhibits the same function, and any configuration is added. You can also

Moreover, in the manufacturing method of the granulated powder of this invention, arbitrary processes may be added to the structure which concerns on the said embodiment.
In addition, the spraying apparatus of this invention may be used for uses other than manufacturing granulated powder.

Next, specific examples of the present invention will be described.
1. Production of granulated powder (Example 1)
<1> First, alloy tool steel powder (manufactured by Epson Atmix Co., Ltd., SKD-11) prepared by a water atomization method and having an average particle diameter of 10 μm was prepared.

  <2> On the other hand, polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA-1717) was prepared as an organic binder.

  Next, tap water was prepared as a solvent, an organic binder was added thereto, and the mixture was stirred while heating to 90 ° C. to dissolve the organic binder. Then, the organic binder solution was prepared by cooling to room temperature. The amount of solvent added was 50 g per 1 g of organic binder. Moreover, the addition amount of polyvinyl alcohol was made into the quantity used as 0.9 mass part with respect to 100 mass parts of metal powder. Moreover, the saponification degree of polyvinyl alcohol was 98-99 mol%, and the polymerization degree was 1700.

  <3> Next, the metal powder and the organic binder solution were mixed to prepare a slurry. The ratio of the metal powder in the slurry was 65% by mass.

<4> Next, the slurry was put into the spray-drying granulator shown in FIG. 1 and granulated to obtain a granulated powder having an average particle size of 60 μm. The spraying apparatus shown in FIGS. 3 to 5 was attached to the spray drying granulator. The temperature of the chamber during granulation (hot air temperature) was 180 ° C., the diameter of the lower disk was 100 mm, and the distance from the discharge port to the pin was 1.5 cm. The slurry supply amount per unit time in this example was determined as a relative value when the slurry supply amount per unit time in Comparative Example 1 described below was 1, and this is shown in Table 1.
The detailed structure of the spray device is also shown in Table 1.

(Examples 2 to 12)
A granulated powder was obtained in the same manner as in Example 1 except that the configuration of the spray device and the production conditions of the granulated powder were changed as shown in Table 1.

(Comparative Example 1)
Granulated powder was obtained in the same manner as in Example 1 except that a spray-drying granulator equipped with the spraying device shown in FIGS.

  Here, FIG. 9 is a top view of the spray device used in Comparative Example 1, and FIG. 10 is a cross-sectional view taken along the line CC in FIG. In the following description, for convenience of explanation, the upper part of FIG. 10 will be described as “upper” and the lower part will be described as “lower”.

  The spray device 2 'shown in FIGS. 9 and 10 is the same as the spray device 2 shown in FIGS. 3 to 5 except that the configuration of the discharge nozzle 24' is different. 9 and 10, the same reference numerals are given to the same configurations as those in FIGS. 3 to 5.

  The discharge nozzle 24 ′ is different from the discharge nozzle 24 shown in FIG. 3 in that the discharge nozzle 24 ′ includes a vertical nozzle 241 extending in the vertical direction and does not include a horizontal nozzle 242. For this reason, the slurry 9 is discharged from the discharge nozzle 24 ′ along the direction orthogonal to the upper surface of the lower disk 231 and downward.

Further, the spray device 2 ′ includes two discharge ports 243 as a whole.
The detailed configuration of the spray device 2 ′ is shown in Table 1.

(Comparative Example 2)
A granulated powder was obtained in the same manner as in Comparative Example 1 except that the configuration of the spraying device and the production conditions of the granulated powder were changed as shown in Table 1.

(Comparative Example 3)
A granulated powder was obtained in the same manner as in Comparative Example 1 except that the number of discharge ports 243 was increased to 4 and the configuration of the spray device and the production conditions of the granulated powder were changed as shown in Table 1.

(Comparative Examples 4 and 5)
3 except that one of the two outlets 243 provided in each horizontal nozzle 242 shown in FIG. 3 is closed and the configuration of the spraying device and the production conditions of the granulated powder are changed as shown in Table 1. Obtained granulated powder in the same manner as in Example 1. In addition, the spraying apparatus used in Comparative Examples 4 and 5 includes two discharge ports in total.

2. When the production of granulated powder Evaluation 2.1 granulating each of Examples and Comparative Examples Evaluation of yield of production efficiency of the granulated powder, the mass of the metal powder contained in the slurry used as a W _in, manufacturing It is the mass of the remaining granulated powder after removing the recovered granulated powder from foreign matter and coarse particles and W _out. And the yield rate (granulation yield) of the granulated powder was calculated by the following formula.
Granulation yield [%] = W _out / W _in × 100
The above calculation results are shown in Table 1.

2.2 Evaluation of Unrecoverable Slurry In each example and each comparative example, a granulated powder was produced using 500 kg of slurry, and then the spray device was removed from the spray drying granulator. And it evaluated in light of the following evaluation criteria about the grade of the slurry adhering to the surface of the spraying board in a spraying apparatus.

<Evaluation of the degree of slurry adhering to the spray plate>
○: Almost no slurry is attached Δ: Slurry is mainly attached to the outer peripheral surfaces of the lower and upper disks ×: Mainly on the outer peripheral surfaces of the lower and upper disks and the surface of the pins Table 1 shows the evaluation results of the slurry adhering.

2.3 Evaluation of production rate The amount of slurry used when the granulated powder was produced in each example and each comparative example and the time required for production of the granulated powder were determined, and the production rate was determined from these values. Was calculated. And the relative value of the production rate in each Example and each comparative example was computed by setting the production rate in the comparative example 1 to 1.
The above calculation results are shown in Table 1.

3. Evaluation of characteristics of granulated powder In each example and each comparative example, a granulated powder was produced using 500 kg of slurry, and the finally obtained granulated powder was recovered. And about the collect | recovered granulated powder, the fluidity | liquidity was measured with the fluidity | liquidity test method of the metal powder prescribed | regulated to JISZ2502: 2012.
The above measurement results are shown in Table 1.

  As is clear from Table 1, in each Example, a high granulation yield (recovery rate) could be realized even if the production rate was increased. Moreover, the characteristic of the manufactured granulated powder was also favorable. From this, it was recognized that according to the present invention, the granulated powder can be produced with high production efficiency.

  Moreover, in each Example, it became clear that the quantity of the slurry adhering to the spray board was also very small. From this, according to the present invention, it has been recognized that the labor and cost required for maintenance of the spraying device and the spray drying granulation device can be reduced, and from this point of view, the production efficiency of the granulated powder can be improved. .

  On the other hand, in Comparative Examples 1 to 3, the slurry is discharged vertically downward. In Comparative Example 1, it was confirmed that the granulation yield was relatively low. Moreover, in Comparative Example 2, as a result of increasing the amount of slurry supplied compared to Comparative Example 1, the granulation yield further decreased. Furthermore, in Comparative Example 3, the number of discharge ports was increased as compared with Comparative Example 1, and the amount of slurry supplied was increased at the same time, but the granulation yield could not be increased.

  On the other hand, in Comparative Examples 4 and 5, the slurry was directly applied to the pins, but the number of discharge ports did not satisfy the conditions, and the granulation yield could not be sufficiently increased.

DESCRIPTION OF SYMBOLS 1 ... Spray drying granulation apparatus, 2 ... Spraying apparatus, 2 '... Spraying apparatus, 3 ... Slurry supply part, 4 ... Drying part, 5 ... Chamber, 6 ... Exhaust part, 7 ... Collection | recovery part, 9 ... Slurry, 21 ... Drive unit, 22 ... rotating shaft, 23 ... spraying plate, 24 ... discharge nozzle, 24 '... discharge nozzle, 31 ... slurry tank, 32 ... piping, 41 ... hot air generator, 42 ... piping, 51 ... drying chamber, 52 ... Duct, 61 ... pipe, 71 ... pipe, 91 ... droplet, 231 ... lower disc, 232 ... upper disc, 233 ... pin, 241 ... vertical nozzle, 242 ... horizontal nozzle, 243 ... discharge port, CF ... circumference , L1 ... distance, O ... rotating shaft, S1 ... step, S2 ... step, S3 ... step

Claims (8)

A substrate provided rotatably around a rotation axis;
A plurality of pins disposed on one surface side of the substrate along a circumference of a circle drawn when the substrate rotates, and arranged in a direction in which an axis intersects the one surface;
A discharge nozzle that is provided on one surface side of the substrate and closer to the rotating shaft than the plurality of pins, and includes three or more discharge ports capable of discharging slurry in a direction parallel to the circle;
A spraying device characterized by comprising:   The spray device according to claim 1, wherein the discharge nozzle discharges the slurry at a supply linear velocity of 5 cm / second or more per one discharge port.   The spray device according to claim 1 or 2, wherein a distance between the discharge port and the pin is 0.5 cm or more and 3 cm or less.   The spray device according to any one of claims 1 to 3, wherein a diameter of the discharge port is 1 mm or more and 6 mm or less.   The spraying apparatus according to any one of claims 1 to 4, wherein a constituent material of the discharge nozzle is a metal material.   The spray device according to any one of claims 1 to 5, wherein the plurality of pins are arranged at equal intervals along the circumference. A spraying device according to any one of claims 1 to 6,
Slurry supply means for supplying slurry to the spraying device;
Drying means for drying droplets of the slurry formed by the spraying device;
A spray-drying granulator characterized by comprising: A substrate provided rotatably around a rotation axis;
A plurality of pins disposed on one surface side of the substrate along a circumference of a circle drawn when the substrate rotates, and arranged in a direction in which an axis intersects the one surface;
A discharge nozzle that is provided on one surface side of the substrate and closer to the rotating shaft than the plurality of pins, and includes three or more discharge ports capable of discharging slurry;
Providing a spraying device having:
Forming a droplet by discharging slurry from the discharge port toward the pin and applying the slurry to the pin in a state where the substrate and the plurality of pins are rotated around the rotation axis;
Drying the droplets to obtain a granulated powder;
A method for producing a granulated powder, comprising:

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