JP2790228B2 - Batch operation method of centrifugal fluidized crusher - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverizing apparatus for finely pulverizing ceramics or inorganic or organic compounds, and more particularly, to a steel ball or a ceramic ball provided with a rotating plate and an outer ring and housed inside the apparatus. The present invention relates to a batch operation method of a centrifugal fluidized-pulverization device that pulverizes a raw material by centrifugally flowing a pulverizing medium such as the above.

[0002]

2. Description of the Related Art There are various types of pulverizers such as a tube mill and a vertical mill. A rotating plate is placed upward and the rotating plate is rotated to store steel balls or ceramics contained therein. Grinding media such as balls
It is called a ball. ) Is generally known as a vertical ball mill in which raw materials are crushed and ground by circulating motion.

[0003] In this type of vertical ball mill which has been used for a long time, the crushing and grinding actions are weak, or the energy input to the apparatus is easily consumed in addition to the crushing and grinding actions, and the energy efficiency is low. There was a problem. Accordingly, the present applicant has filed a patent application for a centrifugal flow pulverizer having a rotating dish and a fixed ring (outer ring) as described below. (Japanese Patent Application Nos. 60-265379 and 60-266)
867-266872, 61-99745, 6
No. 1-207603).

FIG. 5 shows an example of such a centrifugal fluidized crusher. The rotating plate 6 has a conical dish surface 6a whose rotating shaft is oriented vertically and whose diameter increases downward. And the vertical cross section of the plate surface 6a extends from the center to the outer periphery.
It is a rotatable dish-shaped thing which has a concavely curved shape. The outer peripheral ring 7 has at least an inner wall surface whose upper part is reduced in diameter upward, the longitudinal cross section of the inner wall surface is concavely curved, and is provided coaxially with the rotating plate 6. It is stationary. The centrifugal fluidized crusher 1 is configured such that the plate surface 6a of the rotating plate 6 and the inner wall surface of the outer peripheral ring 7 have a continuous smooth surface except for a minute gap 19 between the rotating plate 6 and the outer peripheral ring 7. Is formed.

[0005] Reference numeral 8 denotes a casing that covers the main body of the pulverizer, and an outer peripheral ring 7 is attached to the inner surface of the casing 8 via a connecting member 9. Reference numeral 10 denotes a column base, which pivotally supports the rotating plate 6 via a bearing 11.
The rotating shaft 2 is connected to a driving device such as an electric motor via a reduction mechanism or the like. At the center of the ceiling of the casing 8, there is provided a feed pipe 12 for the raw material, and a duct 13 is provided so as to surround the feed pipe 12, and a rotary cylinder 14 is connected to the duct 13.

In the present embodiment, the outer ring 7 is lined with a liner, and is provided with a number of slits or small holes 15 so as to penetrate the wall surface. A side cover 16 is provided between the bottom of the outer peripheral ring 7 and the inner surface of the casing 8, and an air introduction chamber 17 is formed between the side cover 16, the casing 8 and the outer surface of the outer peripheral ring 7. Thus, air can be introduced from the air introduction pipe 18.
The upper end of the side cover 16 is sealed to the outer surface of the side of the outer peripheral ring 7.

On the other hand, a clearance 19 of 10 to 30% of the minimum ball diameter is provided between the outer peripheral edge of the rotating plate 6 and the inner peripheral edge of the bottom of the outer peripheral ring 7, and the bottom cover 20 is located below the clearance 19. It is provided to cover the side. In this embodiment, air can be introduced into the bottom cover 20 by forming a through hole in the side cover 16 or connecting an air introduction pipe. The bottom cover 20 and the air introduction chamber 17 are connected to a pipe 21 for extracting and transporting the powder, and the pipe 21 is arranged so that the powder can be returned to the input pipe 12. . Also,
A scraper 22 is fixed to the lower side of the outer peripheral edge of the rotating plate 6, and is configured to collect powder particles falling into the bottom cover 20 toward a connection portion of a pipe 21 for extraction.

[0010] The lid 2 is so covered as to cover the upper surface of the casing 8.
8 are provided. The rotary cylinder 14 is inserted into the center of the top of the lid 28, and is pivotally supported by a bearing 29. The rotary cylinder 14 is connected to a driving device (not shown) by appropriate power transmission means such as a pulley 29a and a belt 29b. The upper end of the rotary cylinder 14 and the lower end of the duct 13 are rotatably connected by a connecting mechanism.

A classifier 3 is provided at the lower end of the rotary cylinder 14.
0 is continuously provided. In this embodiment, the classifier 30 is erected on a pair of upper and lower rotating disks 31, 32, a first blade 33 sandwiched between the edges of the disks 31, 32, and an edge of the disk 31. A second blade 34 and a third blade 35 vertically provided at an edge of the disk 32. Further, a stirring blade 36 is provided so as to surround the classifier 30. The blade 36 is connected to the discs 31 and 32 via a stay (not shown), and rotates together with the classifier 30.

In the classifier 30, the air containing the pulverized material is classified by the first blade 33 after the particles are dispersed by the third blade 35 and the stirring blade 36. It flows into the center between 32 and is extracted to the rotary cylinder 14. On the other hand, the coarse powder classified by the first blade 33 flows along the inner surface of the lid 28 and returns to the crushing chamber 27 by the circulation fan effect of the second blade 34.

In the crushing device thus configured,
The raw material is charged into the crushing chamber 27 from the charging pipe 12. On the other hand, as the rotating plate 6 rotates, the grinding medium (steel ball or ceramic ball) circulates in the grinding chamber 27 between the outer peripheral ring 7 and the plate surface 6a, and revolves around the axis of the rotating plate 6. A "spiral movement" is performed, which combines a movement with a movement, and the raw material is crushed during that time. Also,
From the air introduction pipe 18 to the air introduction chamber 17 and the bottom cover 2
The air introduced into the chamber 0 flows into the crushing chamber 27 through the clearance 19, the slit or the small hole 15, and reaches the classifier 30 with the powder generated by the crushing. The fines are returned to the crushing chamber 27 again, and the fines are sent to the collecting means via the rotary cylinder 14 and the duct 13.
Collected in the collector.

The particles that have escaped from the crushing chamber 27 through the slits or small holes 15 or the clearance 19 are returned into the crushing chamber 27 by the conduit 21 and the charging pipe 12.

[0013]

In the conventional centrifugal flow pulverizer shown in FIG. 5 as described above, zirconia, alumina, silicon carbide, silicon nitride, steel balls and the like are used as a pulverizing medium. Depending on the degree of fineness of the required product of the pulverized material, a batch operation as well as a continuous operation can be performed. Generally, those having a relatively large processing capacity and a product grade not so severe are operated continuously. To obtain a product having a very small product grain size even with a small throughput, batch operation by batch operation is necessary. However, the operating conditions have been conventionally used, for example, as shown in FIG. 6, and the grinding time reaches the limit time t _a exceeds the 80 minutes after the average particle size Dp ₅₀ is reaching the limit particle diameter Da, more Even if it is pulverized, agglomeration occurs and the average particle size does not become smaller than the limit particle size Da, and there is a problem that a product having a required product particle size smaller than this cannot be obtained.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, to effectively perform pulverization and to obtain a required ultra-fine pulverized product, the batch operation method of the centrifugal fluidized pulverizer according to the present invention comprises:
A shape in which the rotation axis is oriented vertically and has a dish surface having a conical shape whose diameter increases downward, and the longitudinal section of the dish surface is concavely curved from the center to the outer periphery . A rotatable dish-shaped rotating dish, and at least an upper portion having an inner wall surface whose diameter is reduced upward, the longitudinal section of the inner wall surface being concavely curved, and coaxial with the rotating dish. And a stationary outer peripheral ring is provided around the rotating plate, and the counter surface of the rotating plate and the inner wall surface of the outer peripheral ring have a continuous smooth surface except for a minute gap between the rotating plate and the outer peripheral ring. In the operation of the batch operation of the centrifugal fluidized crusher formed in the above, when it is desired to obtain in a short time a product having an average particle size of 4 μm or more after crushing the crushing medium to be stored together with the raw material in the centrifugal fluidized crusher. Has a large or medium diameter ball with a diameter of about 5 to 10 mm, When it is desired to obtain a finely pulverized product having a diameter of about 3 to 4 μm in a short time, use a medium or small diameter ball having a diameter of about 3 to 5 mm, and obtain an ultrafine pulverized product having an average particle size of less than 3 μm after pulverization. If desired, long-term operation was performed using a small-diameter ball having a diameter of 3 mm or less.

[0015]

In the batch operation method of the centrifugal fluidized crusher according to the present invention, when the average product particle size is large, the device is operated for a short time with a large or medium diameter ball, and when the product average particle size is small, it is used for a long time with a small ball. drive. When the average particle size of the product is about 3 to 4 μm, which is an intermediate product, a product having a desired size can be obtained by operating for a short time with a medium or small diameter ball.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 4 relate to an embodiment of the present invention.
FIG. 1 is an overall longitudinal sectional view of a centrifugal fluidized crusher, FIG. 2 is a longitudinal sectional view of a main part of the centrifugal fluidized crusher, FIG. 3 is a correlation curve diagram of operation time and average particle size of a product, and FIG. FIG.

In FIG. 1, the rotating plate 6 is connected to an output shaft of a speed reducer 25 via a rotating shaft 2 and a coupling 2a vertically provided below the center of the rotating plate 6, and a variable speed motor 26 is provided.
Is driven to rotate. On the other hand, small clearance 1
An outer peripheral ring 7 is disposed around the rotating plate 6 with a column 9 and a base 23 interposed therebetween, and a pulverizing chamber 27 which is a space formed by the rotating plate 6 and the outer peripheral ring 7 is formed by a conventional technique. As described above, the raw material is subjected to the centrifugal flow pulverizing action of the pulverizing medium and is pulverized or ultra-pulverized. A cap-shaped cylindrical tube 40 having a top plate 40 a is placed on the upper part of the outer peripheral ring 7 and connected to the outer peripheral ring 7. A partition plate 42 made of a horizontal disk having a plurality of through holes 44 is fixedly provided in the middle of the cylindrical tube 40.
The bag filter element 50 is provided in the through hole 44 with the partition plate 4.
2 is disposed so as to protrude and drop into a classifying chamber 47 formed below. Further, a venturi tube 46 is provided above the through hole 44, and a compressed air supply tube 60 for blowing compressed air to the inner surface of the bag filter element 50 is guided from outside the venturi tube above the venturi tube 46. Nozzle 6
Oa is disposed to face the Venturi tube 46. Cylindrical tube 40
An exhaust pipe 48 for dust-containing gas is provided at the center of the top plate 40a. The variable speed motor 26, the speed reducer 25, and the column base 24 configured as described above are fixed to the upper surface of the common base 100. The centrifugal flow pulverizer 1 of the present invention can perform both intermittent operation (batch operation) and continuous operation, and has wide versatility. When a batch operation is performed, the amount of intake air into the apparatus is kept small so as not to allow the pulverized fine powder to leak from the clearance 19, and the sieve of the bag filter element 50 is of a very small size so as not to allow the fine powder to escape.

The operation of the present invention configured as described above will be described. In the grinding chamber 27, for example, a large number of grinding media made of, for example, spherical balls are charged. First, a pulverized raw material is charged into the apparatus from a charging pipe (not shown). As the rotating plate 6 rotates, the raw material and the grinding medium are combined with a circular motion (arrow S) circulating between the inner wall surface 7a of the outer peripheral ring 7 and the plate surface 6a, and a revolving motion around the axis of the rotating plate 6. A spiral motion (centrifugal flow) is performed as if twisting a rope by, while grinding or stripping of the pulverized raw material is performed.
That is, when the rotating plate 6 is rotated, the crushing medium is moved in the outer peripheral direction by centrifugal force, and crawls up the inner wall surface 7a of the outer peripheral ring 7 by this velocity energy. It separates from the inner wall surface 7a and falls on the plate surface 6a of the rotating plate 6. The crushed medium that has moved onto the dish surface 6a is again moved toward the outer peripheral ring 7 along the dish surface 6a.

When the rotating plate 6 is rotated, the grinding medium revolves in the circumferential direction at a speed lower than the rotating speed of the rotating plate 6. Therefore, the grinding medium is applied to the dish surface 6a as described above.
In addition to the vertical circular movement S circulating through the inner wall surface 7a and the inner wall surface 7a, it also performs a revolving motion that rotates around the axis of the rotating plate 6, and performs a spiral traveling motion such as a twine that combines these two motions. Centrifugal flow).

As described above, the crushing medium moves up the inner wall surface 7a while maintaining the movement of the rotating plate 6 in the circumferential direction. When the inner wall surface 7a is fixed, the crushing medium is moved. Of the inner wall surface 7a as it is with the circumferential speed (revolution speed) and the speed at which the pulverizing medium rises.
And the speed of the grinding media. Therefore, the speed difference between the crushing medium and the inner wall surface 7a becomes extremely large, and the grinding action by the action of the crushing medium when moving on the inner wall surface 7a becomes extremely strong.

Further, the plate surface 6a is detached from the inner wall surface 7a.
Since the grinding medium that has landed on the upper surface smoothly rolls down along the plate surface 6a, the potential energy obtained when running up the inner wall surface 7a by the movement when rolling down the plate surface 6a is used in the radial direction. Since the kinetic energy can be converted into the kinetic energy, the energy once applied to the pulverizing medium can be effectively used for the peeling action without unnecessarily consuming the energy. Further, when descending along the plate surface 6a, the grinding medium slides on the plate surface 6a, so that grinding or peeling is performed even during this descending movement.

FIG. 3 shows the operation time (crushing time)
t and the average particle size Dp of the product₅₀Shows a correlation with
Rica crushing material (starting particle size 82 μm) with a rotating dish diameter of 400
batch at 500rpm with centrifugal fluidized grinding machine
The result in the case of performing pulverization by operation is shown. Grinding media
Is a single zirconia boad of 10mm, 5mm and 3mm respectively
Used. According to FIG. 3, 10 mm described in FIG.
Ball aggregation phenomenon (limit time t_a Reaches the critical particle size Da
Similarly to the case of 5 mm ball, the grinding time t =
Agglomeration occurs at 60 minutes, and even after grinding,
Average particle diameter Dp ₅₀Does not decrease, but rather increases. on the other hand,
In the case of 3mm balls, even for a very long batch operation
No aggregation was observed and the average particle diameter Dp₅₀Decreases monotonically.

The above tendency is also observed in other crushing materials (alumina, silicon nitride, talc, etc.) other than fused silica, and is considered to have versatility. Therefore, as shown in FIG.
The ball diameter and operation time of the grinding media are determined in consideration of the type of the crushing material, the processing capacity, the desired product particle size, and the like. First, in order to obtain a product having an average particle size of 4 μm or more, for example, 5 to 8 μm, a conventional 10 mm ball or 5 mm is used.
Even a 20 mm ball is pulverized in a short time of about 20 minutes and has a large processing capacity. On the other hand, when it is desired to obtain an intermediate product having an average product particle size of about 3 to 4 μm, use a 5 mm ball or a 3 mm ball.
Pulverization is performed for a short time of about 0 to 60 minutes. In order to obtain an ultrafine pulverized product having an average product particle size of less than 3 μm, a ball having a small diameter that is unlikely to cause agglomeration, for example, a 3 mm ball or less, is operated for a long time of 100 minutes or more.

Since the characteristic curve shown in FIG. 3 is slid up and down somewhat depending on the crushing material, a crushing material having a high crushing frequency and a crushing material having a small allowable width of a desired particle size are subjected to a test operation in advance. It is desirable to collect and organize data.

In the batch operation method of the present invention, since the characteristics in the correlation between the grinding media ball diameter and the product average particle size in the centrifugal fluidized grinding device are sufficiently grasped and the operation is adapted to the characteristics, efficient grinding can be performed. As a result, a product having a desired particle size can be obtained in a minimum necessary time.

[0026]

As described above, according to the batch operation method of the present invention, a pulverizing medium having an appropriate ball diameter is selected, and efficient operation is performed, so that a product having a required particle size can be obtained quickly. .

[Brief description of the drawings]

FIG. 1 is an overall vertical cross-sectional view of a centrifugal fluidized crusher according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of a centrifugal fluidized-pulverizing apparatus according to an embodiment of the present invention.

FIG. 3 is a diagram showing a correlation curve between an operation time and an average particle size of a product in a batch operation according to an example of the present invention.

FIG. 4 is an explanatory diagram of an operation guideline of a batch operation method according to an embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a main part of a conventional centrifugal flow pulverizer.

FIG. 6 is a diagram showing a correlation curve between the operation time and the average particle size of a product in a batch operation of a conventional centrifugal fluidized grinding device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Centrifugal fluid crushing apparatus 2 Rotating shaft 6 Rotating dish 6a Dish surface 7 Outer ring 7a Inner wall surface 18 Air introduction pipe 19 Clearance 27 Grinding chamber 40 Cylindrical pipe 40a Top plate 40b Cylindrical pipe 40c Cover 40d Hinge 42 Partition plate 44 Through hole 46 venturi tube 47 classifying chamber 48 blowout discharge pipe 50 bag filter element 60 compressed air supply pipe 60a nozzle 100 common base S circular A single ball Dp ₅₀ average particle diameter Da limit particle diameter t _a time limit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B02C 17/00-17/20

Claims (1)

(57) [Claims] 1. A rotating shaft center is oriented in a vertical direction, has a conical dish surface which expands in diameter downward, and a longitudinal section of the dish surface is concave from a central portion to an outer peripheral portion. A rotatable dish-shaped rotating dish having a curved shape, and at least an upper portion having an inner wall surface whose diameter is reduced upward, and a vertical cross section of the inner wall surface having a concavely curved shape, An outer peripheral ring which is provided coaxially around the rotating plate and is stationary,
Batch operation of the centrifugal fluidized crusher in which the plate surface of the rotating plate and the inner wall surface of the outer peripheral ring are formed in a continuous smooth surface except for a minute gap between the rotating plate and the outer peripheral ring. In the case where it is desired to obtain a product having an average particle size of 4 μm or more after grinding in a short time, a grinding medium stored in the centrifugal fluidized grinding device together with the grinding material, a large or medium diameter having a diameter of about 5 to 10 mm. When it is desired to obtain a finely pulverized product having an average particle size of about 3 to 4 μm in a short period of time, use a medium or small diameter ball of about 3 to 5 mm. A batch operation method of a centrifugal fluidized pulverizer that operates for a long time using a small-diameter ball having a diameter of 3 mm or less when an ultra-fine pulverized product of less than 3 μm is desired.