JPH0691190A - Operation of centrifugal fluidized pulverizer - Google Patents

Abstract

PURPOSE:To perform operation with the highest productivity in response to a required product particle diameters by selecting the optimal combinations of the pulverizing medium ball diameters with the revolutions of a rotation bowl according to the average particle diameter of the required product and performing continuous operation. CONSTITUTION:In the case of a product of <5mum average particle diameter, small diameter balls of <=3mum diameter are used as the pulverizing medium and low speed operation of <600rpm of a rotating bowl is performed. In the case of a product of 3-5mum average particle diameter, medium or large diameter balls of 5-10mum diameter are used as the pulverizing medium and high speed operation of <=600rpm of the rotating bowl is performed. In the case of a product of 1-3mum average particle diameter, medium or large diameter balls of 5-10mm diameter are used as the pulverizing medium and high speed operation of <=600rpm of the rotating bowl is performed, or medium diameter balls of 5mm diameter are used instead as the pulverizing medium and low speed operation of <600rpm of the rotating bowl is performed. In the case of a product of <1mum average particle diameter, medium or large diameter balls of 5-10mm diameter are used as the pulverizing medium and high speed operation of <=600rpm of the rotating bowl is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crushing device for finely crushing ceramics or an inorganic or organic compound, and more specifically, to a steel ball or a ceramics ball equipped with a rotating dish and an outer peripheral ring and housed inside the device. The present invention relates to a method of operating a centrifugal fluidizing and pulverizing apparatus in which a raw material is continuously pulverized by centrifugally flowing a pulverizing medium such as.

[0002]

2. Description of the Related Art There are various types of crushing devices such as tube mills and vertical mills, but the steel balls or ceramics housed inside are installed by placing the rotary plate upward and rotating the rotary plate. Grinding media such as balls (hereinafter,
Called a ball. ) Is circulated to pulverize and grind raw materials, which is commonly known as a vertical ball mill.

In this type of vertical ball mill that has been used for a long time, the crushing and grinding actions are weak, or the energy input to the device is easily consumed in addition to the crushing and grinding actions, and the energy efficiency is low. There was a problem. Therefore, the present applicant has applied for a patent for a centrifugal fluidizing and crushing device having a rotating dish and a fixed ring (peripheral ring) as described below. (Japanese Patent Application Nos. 60-265379 and 60-266)
867 to 266872, ibid. 61-99745, ibid. 6
1-207603).

FIG. 5 shows an embodiment of these centrifugal fluidizing and crushing devices. The rotating dish 6 has a rotating shaft centered in the vertical direction, and at least a central portion of the dish surface expands downward. And has a shape in which the longitudinal cross section of the dish surface is curved in a concave shape and is rotatable. The outer peripheral ring 7 has an inner wall surface in which at least the upper part is reduced in diameter upward,
The inner wall surface has a shape in which a vertical cross section is curved in a concave shape, and is coaxially provided around the rotary plate 6 and is stationary. In the centrifugal fluidizing and crushing device 1, the dish surface of the rotary dish 6 and the inner wall surface of the outer peripheral ring 7 form a continuous smooth surface except for the minute gap 19 between the rotary dish 6 and the outer peripheral ring 7. Has been formed.

Reference numeral 8 is a casing for covering the main body of the crusher, and the outer peripheral ring 7 is attached to the inner surface of the casing 8 via a connecting member 9. Reference numeral 10 is a column base, which pivotally supports the rotating dish 6 via a bearing 11.
The rotating shaft 2 is connected to a prime mover such as an electric motor via a reduction mechanism. At the center of the ceiling of the casing 8, a raw material feeding pipe 12 is installed, and a duct 13 is provided so as to surround the feeding pipe 12, and a rotary cylinder 14 is connected to the duct 13.

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

On the other hand, there is a clearance 19 of 10 to 30% of the minimum ball diameter between the outer peripheral edge of the rotary plate 6 and the inner peripheral edge of the bottom of the outer peripheral ring 7, and the bottom cover 20 is below this clearance 19. It is installed so as 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 pipeline 21 for extracting and transporting the powder and granules, and the pipeline 21 is arranged so that the powder and the granules can be returned to the charging pipe 12. . Also,
A scraper 22 is fixedly provided on the lower side of the outer peripheral edge of the rotary dish 6, and is configured to collect the powder particles falling in the bottom cover 20 toward the connecting portion of the pipe line 21 for extraction.

The lid 2 covers the upper surface of the casing 8.
8 are provided. The rotary cylinder 14 is inserted in the center of the top of the lid 28, and is rotatably supported by a bearing 29. The rotary cylinder 14 is connected to a drive device (not shown) by an 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.

At the lower end of the rotary cylinder 14, the classifier 3 is attached.
0s are serially arranged. 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. The second blade 34 and the third blade 35 are provided vertically on the edge of the disc 32. 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 is rotated 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, and the fine powder is divided into the disc 31, It flows into the center between 32 and is withdrawn 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 by the circulation fan effect of the second blade 34 and is returned to the crushing chamber 27.

In the crushing device configured as described above,
The raw material is charged into the crushing chamber 27 through the charging pipe 12. On the other hand, as the rotary disc 6 rotates, the grinding medium (steel balls or ceramic balls) circulates in the grinding chamber 27 between the outer peripheral ring 7 and the plate surface 6a, and revolves around the axis of the rotary plate 6. A "spiral motion" is performed, which is like a rope by the combination with motion, and the raw material is crushed in the meantime. Also,
From the air introduction pipe 18 to the air introduction chamber 17 and the bottom cover 2
The air introduced into 0 passes through the clearance 19, the slits or the small holes 15 into the crushing chamber 27, reaches the classifier 30 with the powder generated by the crushing, undergoes the classifying action, and undergoes the coarse powder. The fine particles are returned to the crushing chamber 27 again, and the fine particles are sent to the collecting means via the rotary cylinder 14 and the duct 13.
It is collected by a collector.

Further, the particles that have exited from the crushing chamber 27 through the slits or small holes 15 or the clearance 19 are returned to the crushing chamber 27 by the conduit 21 and the charging pipe 12.

[0013]

In the conventional centrifugal fluidized crushing apparatus shown in FIG. 5 as described above, zirconia, alumina, silicon carbide, silicon nitride, steel balls, etc. are used as the crushing medium, and the rotating dish diameter It was customary to use a ball having a diameter of 10 mm in an apparatus having a diameter of 400 to 500 mm and to rotate the rotating dish at 500 rpm. Then, in order to obtain an ultrafine pulverized product in which the required fineness of the product to be pulverized is severe, batch operation that can prolong the pulverization time is adopted rather than continuous operation, and it takes a long time to reach the required particle size. Although the operation was carried out, there were drawbacks such as low productivity, requiring setup time such as product removal and supply of crushed material after each batch operation. The method of the present invention solves these problems and provides a good crushing method that efficiently produces a product having a desired product particle size even in continuous operation and improves productivity.

[0014]

[Means for Solving the Problems] In order to solve the above-mentioned problems and to carry out effective pulverization and continuously obtain the required ultrafine pulverized products, the operation method of the centrifugal fluidized pulverization apparatus of the present invention is , At least a central portion having a dish surface that expands downward, and a rotatable dish-shaped rotating dish having a shape in which the longitudinal cross section of the dish surface is concavely curved; Has an inner wall surface that decreases in diameter, and the longitudinal cross section of the inner wall surface is curved in a concave shape. The inner wall surface is provided coaxially with the rotary plate and is stationary or driven to rotate in a direction opposite to the rotary plate. And a peripheral surface of the rotary plate and an inner wall surface of the peripheral plate, except for a minute gap between the rotary plate and the peripheral ring,
In a continuous operation of a centrifugal fluidizing and pulverizing apparatus formed on a continuous smooth surface, when it is desired to obtain a product having an average particle size of 5 μm or more, a pulverizing medium to be stored in the centrifugal fluidizing and pulverizing apparatus together with a pulverizing raw material is used. Is a small diameter ball of 3 mm or less, and the rotation speed of the rotating dish is less than 600 rpm, and when a product having an average particle size of 3 to 5 μm is desired, a medium or large diameter ball is used. In addition, the rotation speed of the rotating dish is set to 600 rpm or higher, and if you want to obtain a product with an average particle size of 1 to 3 μm, the diameter is 5 to 5.
Use a medium or large diameter ball of 10 mm and a high speed operation of the rotating dish rotation speed of 600 rpm or more, or use a medium diameter ball of 5 mm and a low speed operation of the rotating dish rotation speed of less than 600 rpm, and average. If you want to obtain a product with a particle size of less than 1 μm, the diameter is 5 to 10 mm.
A medium or large diameter ball was used, and high speed operation was performed at a rotating disc rotation speed of 600 rpm or more.

[0015]

In the operation method of the centrifugal fluidizing and grinding apparatus of the present invention, the optimum combination is selected from the combination of the ball diameter of the grinding medium and the rotation speed of the rotary dish according to the average particle diameter of the desired product, and the continuous operation is carried out. The operation with the highest productivity for the required product particle size is performed.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 to 4 relate to an embodiment of the present invention,
Fig. 1 is an overall vertical sectional view of the centrifugal fluidizing and pulverizing apparatus, Fig. 2 is a longitudinal sectional view of main portions of the centrifugal fluidizing and pulverizing apparatus, Fig. 3 is a correlation curve diagram between the pulverized amount and the average particle size of the product, and Fig. 4 is a continuous operation method. It is an explanatory view of the selection guideline of.

In FIG. 1, the rotary plate 6 is connected to the output shaft of the speed reducer 25 via a rotary shaft 2 and a coupling 2a which are vertically provided below the center of the rotary plate 6, and a variable speed electric motor 26 is provided.
It is driven to rotate by. On the other hand, a small clearance 1
An outer peripheral ring 7 is disposed around the rotary plate 6 with a column base 24 and a pedestal 23 separated by 9, and in the crushing chamber 27 which is a space formed by the rotary plate 6 and the outer peripheral ring 7, the conventional technology is used. The raw material configured as described above is subjected to centrifugal fluidizing and pulverizing action by a pulverizing medium, and is pulverized or ultrafine 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 disc 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
It is arranged so as to project and hang down in a classification chamber 47 formed below 2. Further, a venturi pipe 46 is provided above the through hole 44, and a compressed air supply pipe 60 for blowing compressed air to the inner surface of the bag filter element 50 is guided from above the venturi pipe 46 and blown out. Nozzle 6
0a is arranged to face the Venturi tube 46. Cylindrical tube 40
A discharge 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 fixedly mounted on the upper surface of the common base 100.

The operation of the present invention constructed as above will be described. In the crushing chamber 27, a large number of crushing media composed of, for example, spherical balls are loaded in advance. First, the crushed raw material is charged into the apparatus through a charging tube (not shown). A combination of a circular motion (arrow S) in which the crushing raw material and the crushing medium circulate between the inner wall surface 7a of the outer peripheral ring 7 and the plate surface 6a along with the rotation of the rotary plate 6 and the revolving motion around the axis of the rotary plate 6. A spiral movement (centrifugal flow) is carried out, which causes the rope to twist, and the ground material is ground or stripped in the meantime.
That is, when the rotating dish 6 is rotated, the crushing medium is moved in the outer peripheral direction by the centrifugal force, and the velocity energy crawls up the inner wall surface 7a of the outer peripheral ring 7, and when the creeping force becomes smaller than gravity, It separates from the inner wall surface 7a and falls on the dish surface 6a of the rotary dish 6. The grinding medium that has moved to the dish surface 6a is again moved toward the outer peripheral ring 7 along the dish surface 6a.

When the rotary dish 6 is rotated, the grinding medium revolves in the circumferential direction at a speed lower than the rotational speed of the rotary dish 6. Therefore, as described above, the crushing medium is the dish surface 6a.
In addition to the vertical circular motion S that circulates along the inner wall surface 7a and the orbital motion that rotates around the axis of the rotary plate 6, a spiral progressive motion that twists the rope combining these two motions ( Centrifugal flow).

As described above, the crushing medium performs the movement of climbing up the inner wall surface 7a while maintaining the movement of the rotary dish 6 in the circumferential direction. When the inner wall surface 7a is fixed, the crushing medium is The circumferential speed (revolution speed) and the composite speed of the crushing speed of the crushing medium are the same as the inner wall surface 7a.
And the speed difference 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 dish surface 6a is detached from the inner wall surface 7a.
Since the crushing medium that has landed on the top smoothly rolls down along the dish surface 6a, the potential energy obtained when running up the inner wall surface 7a in the radial direction is obtained by the motion of rolling down the dish surface 6a. Since it can be converted into kinetic energy to, the energy once applied to the pulverizing medium can be effectively used for the peeling action without consuming it unnecessarily. Furthermore, when descending along the dish surface 6a, the grinding medium slides on this dish surface 6a, so that grinding or peeling is performed even during this descending movement.

The one shown in FIG. 3 has a rotating dish diameter of 400 mm.
Shows the correlation between the average particle size Dp ₅₀ of the product and the crushed amount Q when the ball diameter and the number of rotations of the rotary plate are continuously operated in the centrifugal fluidized crusher of No. Of fused silica. As the grinding media, single zirconia balls of 10 mm, 5 mm and 3 mm were used. According to FIG. 3, in the low speed operation of the rotation speed of 500 rpm, when the product average particle diameter Dp ₅₀ exceeds 5 μm, the crushing amount Q is larger than that of the 5 mm balls and the 10 mm balls when the 3 mm balls are used. The more the 3 mm balls are used, the smaller the crushing amount Q is. 5 in total in high-speed operation of 700 rpm
The crushing amount Q is higher than that at low speed operation of 00 rpm, especially 5 mm over 3 mm balls over almost the entire range of average particle size.
The results show that the crushed amount Q is high when the balls are 10 mm balls. And, even if the crushed material changed, almost the same result was obtained.

From the above results, the product average particle diameter Dp ₅₀ is 5
In order to carry out continuous operation with a high crushing amount Q in accordance with the values exceeding μm, 3 to 5 μm, 1 to 3 μm, and less than 1 μm, 600 rpm
With the boundary of 600 rpm, the operation is slower than 600 rpm.
High speed operation is defined as operation above rpm, 10mm, 5m
The m and 3 mm balls are referred to as a large diameter ball, a medium diameter ball, and a small diameter ball, respectively, and as shown in FIG.
_{If 50} = more than 5 μm, a 3 mm ball or less
Low speed operation with a 2 mm ball, 5 at Dp ₅₀ = 3-5 μm
-10 mm ball for high speed operation, Dp ₅₀ = 1-3 μm, 5 mm ball for low speed operation, or 5-10 m
A high crushing amount Q can be obtained by high-speed operation with m balls and high-speed operation with 5-10 mm balls in order to obtain an ultrafine pulverized product having Dp ₅₀ = 1 mm or less.

Since the characteristic curve shown in FIG. 3 is slid up and down depending on the crushed material, the crushed material with a high crushing frequency and the crushed material with a small allowable range of the desired particle size should be tested in advance. It is desirable to collect and organize the data.

In the continuous operation method of the present invention, since the characteristics in the correlation between the pulverization amount and the product average particle diameter in the centrifugal fluidizing pulverizer are sufficiently grasped and the operation suitable for them is performed,
Efficient crushing is performed, and the productivity of products with desired particle size is high.

[0026]

As described above, according to the operating method of the present invention, a grinding medium having an appropriate ball diameter is selected, and efficient operation is performed at an appropriate number of revolutions, so that a product having a required particle size can be obtained. It can be obtained quickly and productivity can be improved.

[Brief description of drawings]

FIG. 1 is an overall vertical cross-sectional view of a centrifugal fluidizing and crushing apparatus according to an embodiment of the present invention.

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

FIG. 3 is a correlation curve diagram between the pulverized amount and the average particle size of the product in continuous operation according to the example of the present invention.

FIG. 4 is an operation guide explanatory diagram of the continuous operation method according to the embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a main part of a conventional centrifugal fluidizing and pulverizing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Centrifugal fluid pulverizer 2 Rotating shaft 6 Rotating dish 6a Dish surface 7 Outer ring 7a Inner wall surface 18 Air inlet tube 19 Clearance 27 Grinding chamber 40 Cylindrical tube 40a Top plate 40b Cylindrical tube 40c Lid 40d Hinge 42 Partition plate 44 Through hole 46 Venturi pipe 47 Classification chamber 48 Discharge pipe 50 Bag filter element 60 Compressed air supply pipe 60a Blow-off nozzle 100 Common base S Circular motion Dp ₅₀ Average particle size Q Grinding amount

Claims (1)

[Claims] 1. A rotatable dish-shaped rotating dish having at least a central portion having a dish surface that expands downward, and a longitudinal cross section of the dish surface curved concavely, and at least The upper part has an inner wall surface whose diameter decreases upward, and the longitudinal cross section of the inner wall surface is curved in a concave shape. The inner wall surface is coaxial with the rotary plate and is stationary or reverse to the rotary plate. An outer peripheral ring that is driven to rotate in a direction, and the dish surface of the rotary plate and the inner wall surface of the outer peripheral ring form a continuous smooth surface except for a minute gap between the rotary plate and the outer peripheral ring. In the continuous operation of the centrifugal fluidizing and pulverizing apparatus that has been formed, the diameter of the pulverizing medium to be stored in the centrifugal fluidizing and pulverizing apparatus together with the pulverization raw material is 3 in order to obtain a product having an average particle size of 5 μm or more.
The diameter of the ball is 6 mm or less, and the rotation speed of the rotating plate is 6
When operating at a low speed of less than 00 rpm and obtaining a product with an average particle size of 3 to 5 μm, the diameter is 5
If you want to obtain a product with an average particle size of 1 to 3 μm by using a medium or large diameter ball of 10 mm and a high speed operation of the rotating dish rotation speed of 600 rpm or more, the diameter is 5
-10 mm medium or large diameter balls and high speed operation of rotating disc rotation speed of 600 rpm or more, or medium diameter balls of 5 mm and low rotation speed of rotating disc rotation speed of less than 600 rpm, If you want to obtain a product with an average particle size of less than 1 μm, the diameter is 5
A method for operating a centrifugal fluidizing and pulverizing apparatus, which uses medium-sized or large-sized balls of 10 mm and high-speed operation of a rotating dish rotation speed of 600 rpm or more.