JPH074553B2 - Friction grinding method for raw materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention makes raw materials such as agricultural products and minerals rotate, and the raw materials rub against each other and frictionally pulverize to produce ultrafine powder having a very small particle size. The present invention relates to a friction grinding method for raw materials which can be obtained and whose average particle size and particle size distribution can be controlled.

(Prior Art) Conventionally, as a method for finely crushing raw materials such as shells and minerals, a ball mill, a vibration mill, a hammer mill or the like has been used. However, in this case, the wear of the balls, runners, hammers, etc. is remarkable, and the amount of foreign matter mixed in the pulverized material increases. Further, in the conventional crushing method, it is necessary to drive the crusher for a long time in order to obtain submicron particles.

(Problems to be Solved by the Invention) In the conventional pulverizing method, the energy consumption required for pulverizing the raw material into a fine powder is large and the pulverizing time is long. Therefore, the grinding efficiency is very poor and the processing capacity is limited. Further, the particle size distribution of the crushed product is almost determined by the crusher, and it is extremely difficult to change the particle size distribution.

An object of the present invention is to provide a raw material friction pulverization method capable of obtaining ultrafine powder having a very small particle size with good working efficiency and easily and controlling the average particle size and particle size distribution.

(Means for Solving Problems) The present invention has been made to solve the above problems, that is, a raw material is provided between a first rotating body and a second rotating body that face each other in a casing and are independently driven. A raw material which is supplied and swirled by a first rotating body and a second rotating body which rotate at high speed, so that the raw materials are rubbed against each other and frictionally ground, and the frictionally ground raw material is recovered from the rotation center side. The friction grinding method of.

(Operation) Next, the operation of the present invention will be described. First, the raw material (7) is charged through the charging port (4) and is supplied between the first rotating body (2) and the second rotating body (3). A space surrounded by the first rotating body (2) and the second rotating body (3) and the inner wall of the casing (1), and hereinafter, this space is referred to as a crushing zone (6). In the crushing zone (6), the raw material (7) is collected at a fixed position in the radial direction to form a dynamic packed bed (see FIG. 1). The raw material (7) having a dynamic packed bed formed in the crushing zone (6) is swirled by the rotation of the first rotating body (2) and the second rotating body (3), so that the particles of the raw material (7) are A centrifugal force acts, and the centrifugal force causes the particles to move while being pressed against each other in the radial direction. The turning speed at this time changes as it moves away from the first rotating body (2) or the second rotating body (3), so that the raw materials (7) are rubbed and rubbed with each other, and the pulverized rubbed. The fine powder is directed toward the center of rotation, and the fine powder gathers at appropriate positions to form a layer, and the layer is further friction-ground to further reduce the particle size (see FIG. 2). In this way, frictional pulverization is performed at every position in the pulverization zone (6), and if this is repeated, the particle size becomes extremely small. In addition, the size of the particles is gradually reduced from the outer periphery toward the center of rotation by the action of centrifugal force, and the smallest size of the particles is collected by a second rotating body (not shown) using a collecting means such as a suction fan. It is transported from the center of 3) to the discharge port (5) and collected.

Further, when the raw material (7) is frictionally pulverized, an air flow toward the center of rotation is generated in the pulverization zone (6) due to the suction action of the suction fan, etc., so that the particle layer of the raw material (7) is formed in the casing (1).
It can be swiveled without contacting the inner wall, and the inner wall is not worn by the movement of particles. Furthermore, the first rotating body (2)
Since the second rotating body (3) and the second rotating body (3) move at almost the same speed as the particles that come into contact with each other, the first rotating body (2) and the second rotating body (3) are less worn and can be continuously used for a long time. Even if the crushing is continued, the crushing is efficiently performed. Moreover, at this time, by controlling the rotation speeds of the first rotating body (2) and the second rotating body (3) and the suction speed of the fine particles, it becomes possible to control the average particle size and the particle size distribution of the pulverized product. . That is, if the suction speed of the suction fan or the like is kept constant and the rotation speeds of the first rotating body (2) and the second rotating body (3) are increased, the average particle size is reduced, and the suction speed is increased. The average particle size increases as it goes, but the crushed particle size distribution becomes uniform.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.
(1) is a casing, (2) is a casing (1)
It is a rotatable rotary blade or a disk-shaped first rotating body provided inside. (3) is a rotatable rotor or disk-shaped second rotor provided inside the casing (1) facing the first rotor (2).
It is a rotating body, and a suction hole of an appropriate size is bored in the center of the second rotating body (3). Further, the second rotating body (3) can be slid in the horizontal direction to adjust the distance between the second rotating body (3) and the first rotating body (2). Also, each rotating body (2), (3)
The rotation speed and rotation direction of can be set independently. still,
This structure can be easily made by using a general structure, and therefore further description will be omitted. (4) is an inlet provided on the side surface of the casing (1). Reference numeral (5) is an outlet provided on the side surface of the casing (1) opposite to the inlet (4), and the outlet (5) communicates with the central portion of the second rotating body (3). (6) is the inner wall of the casing (1) and the first
A space surrounded by the rotating body (2) and the second rotating body (3), that is, a crushing zone.

Next, the method of the present invention will be described. The first rotating body (2) and the second rotating body (3) are rotated in advance at high speed. First, when the raw material (7) is charged from the charging port (4), the raw material (7) is supplied between the first rotating body (2) and the second rotating body (3) and enters the crushing zone (6). . The raw material (7) having a large particle size, which has entered the crushing zone (6), is driven to the outer periphery by centrifugal force, and the dynamic packed bed is placed between the first rotating body (2) and the second rotating body (3). Form. The raw material (7) that has formed the dynamic packed bed in the crushing zone (6) is the first rotating body (2).
By the rotation of the second rotating body (3), the raw material (7) is frictionally crushed while having the same particle diameters as shown in FIG. 2, and the frictionally pulverized raw material (7) faces the center of rotation.
Collected at appropriate positions in the radial direction, and further crushed by friction. Then, a particle-packed layer is formed which is classified from the outer periphery in order of smaller particle size. The finest particle size is collected at the rotation center, and the finest particle size is carried from the central portion of the second rotating body (3) to the discharge port (5) by using a recovery means (not shown), and thereafter. , Collect only fine powder from the outlet (5).

(Effects of the Invention) Since the present invention is configured as described above, it has the effects described below.

The raw materials (7) are friction crushed while rubbing each other even if they are not crushed for a long time with a conventional crusher, so they become fine powder efficiently in a short time, and the energy required for crushing is drastically reduced compared to the conventional one. .

Since the pulverization efficiency is extremely good, it is possible to significantly reduce the cost of fine powder.

By repeating friction grinding in the grinding zone (6), submicron particles can be obtained, and the average particle size can be made as small as possible.

The crushed particle size and particle size distribution of the raw material (7) can be easily changed by changing the interval between the first rotator (2) and the second rotator (3), their respective rotation speeds and directions, and the suction speeds. It is possible to control.

Since the wear portion of the device is small, foreign matter is not significantly mixed into the friction pulverized product, and fine powder of good quality can be obtained.

Maintenance is very easy because there is almost no change over time in the average particle size and particle size distribution of the ground product due to wear of the device during continuous operation.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment according to the present invention, and FIG. 2 is an explanatory view showing a state in which raw materials are repeatedly crushed by friction. (1) …… Casing, (2) …… First rotating body (3) …… Second rotating body, (7) …… Raw material

Claims (1)

[Claims] 1. A raw material (7) is supplied between a first rotating body (2) and a second rotating body (3) which face each other in a casing (1) and are independently driven, and the raw materials (7) are rubbed with each other. A friction pulverizing method of a raw material, which is friction pulverized and recovers the friction pulverized raw material (7) from a rotation center side.