JP2003220346A - Wet ball mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate an adverse effect of clogging of a multihole plate slit provided on a discharge side of a wet ball mill on quality and efficiency. <P>SOLUTION: A crushed sand material M, which has been supplied together with water from one side end of a hollow cylinder 1 being rotated, is ground by means of a spherical grinding medium B within a grinding chamber 3 and is passed through a number of slits 5 formed in a multihole plate 4 which partitions the other side end to discharge product crushed sand S as slurry. The mesh width of the slits 5 is gradually increased toward the center of the cylinder. At the same time, a plurality of discharge ports 6, which are open to the outer periphery of the cylinder beyond the multihole plate 4, are peripherally provided to form a discharge space 7. The above construction can solve the problem of the prior art. When a clogged slit is rotated to the top and is vibrated, since the slit is expanded in a downward widened state, sand, which clogs the slit, is easily separated from the slit to solve the clogging problem. Water and the product crushed sand are rapidly discharged without delay and overgrinding. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention charges a grinding medium such as steel balls into a rotating hollow cylindrical body and is supplied from the end of the body by rolling and impact of the grinding medium accompanying the rotational movement of the body. The present invention relates to a wet ball mill suitable for grinding water and minerals such as relatively fine-grained rocks to a desired size.

[0002]

2. Description of the Related Art Silica sand, which is used as an aggregate for concrete, was originally collected from natural river sand and later from beaches and sea floors, but rod mills and ball mills that crush rocks to deplete resources and preserve the environment. Is diverted, and the product is finished by adjusting the particle size so that the product is crushed sand specified in JIS. Both types of mills have their own characteristics, but in any case, the crushed sand raw material and water are supplied into a horizontally held hollow cylinder, and this hollow cylinder is rotated to remove the preloaded rods and balls. Generally, a horizontal cylindrical wet crusher that crushes by the rolling and impact force of the crushing medium and discharges and collects the product crushed sand crushed to a certain particle size.

Of these rods, rod mills have long and heavy rods, and although the crushing force is effective for coarse rock, the mobility of the crushed sand raw material that flows in fine sand is low and the efficiency is low. Therefore, a ball mill is considered to be more suitable as a sand mix with a JIS-specified concrete mix. Although several types of developments and improvements have been proposed for wet type ball mills, preventing the grinding medium from being discharged together with the product out of the hollow cylinder during operation is an important operational control requirement. Is one.

FIG. 6 regulates the release of the crushing medium B by a perforated plate 104 having slits so that only the product crushed sand S is allowed to pass along with the remaining material of the crushing medium B whose diameter has been reduced below a certain level and added water. FIG. 4 is a cross-sectional view of a wet ball mill of the related art described above. One end of the hollow cylinder 101 is sealed by a side plate 108, and the crushed sand raw material M is supplied from a supply port 102 provided in the cylinder core. The grinding medium B (steel ball) is previously stored in the grinding chamber 103.
Is charged, and the crushed sand raw material M flows in a slurry state together with water supplied from a water supply port (not shown), and the hollow cylinder 10
The cascading motion, which is a combination of the centrifugal force and the own weight of the rotary motion of 1, causes the crushing action by the falling impact force and rolling of the crushing medium B which is lifted up to the middle and falls, and the product crushed sand S is finished.

The other end of the hollow cylinder 101 regulates the discharge of the crushing medium B and is divided by a perforated plate 104 having a slit that allows only water and slurry product crushed sand S to pass therethrough. Only the product crushed sand S, water, and the remaining material of the crushing medium B, which have passed through the slits by opening the concentric discharge ports 106, are discharged. After this, it is also customary to go through a procedure such as a particle size adjusting means (screen or the like) not shown in the discharge circuit, a magnetic separation and recovery means of the residual material of the grinding medium, and the like.

Although belonging to the above-mentioned conventional type, in order to diversify the conventionally used rod mill into a ball mill as it is, the regulation plate for regulating the operating conditions and the release of the pulverizing medium (rod) is modified for the ball and overpulverized. Japanese Patent Laid-Open No. Sho 11
No. 90255, the perforated plate 204 in which arcuate slits 205 are radially provided as shown in FIG.
The discharge port 206 is closed with the side plate 20 of the hollow cylinder 201.
8 is attached and fixed so that the discharge of the grinding medium B is regulated and only the water and the product crushed sand S are discharged.

[0007]

The porous plate which separates the crushing chamber immediately before the discharge port passes only the slurry-like fluid in which water and product crushed sand are mixed, and the crushing medium (steel ball) larger than the mesh width. It has the effect of blocking and enclosing it in the crushing chamber. However, this effective action also hinders the smooth passage of the fluid when the slits themselves are clogged, and causes the product crushed sand to stagnate in the crushing chamber more than necessary and is overcrushed, resulting in sludge formation. Further, if the water is stagnated more than necessary, the drop impact force of the crushing medium is greatly diminished, which is a major cause of lowering the crushing efficiency. In the prior art of FIG. 7, the crushed object also rotates along the direction of rotation of the cylinder, so if the slit is along the direction of rotation of the cylinder, it is determined that crushed sand and water will easily escape from the slit. , It is described that an arcuate slit as shown in FIG. However, if the slits are opened along the cascading motion of crushed sand and water, the action of promoting passage of the fluid can be expected, but it may have a slightly different meaning from the prevention of clogging of the slits. Originally, the clogging is mainly caused by a phenomenon in which a steel ball worn and reduced in diameter in the crushing chamber is pushed into the slit and fitted. The clogging occurred once when the hollow cylinder rotated and moved to the vicinity of the apex, the vibration of the cylinder itself caused by the impact of the crushing medium often caused it to fall off due to its own weight, so that the clogging occurred. In removing the clogging, it is hard to believe that the effectiveness of the slit formed into an arc shape is absolutely perfect.

Another problem in the wet type ball mill of the type shown in FIGS. 6 and 7 is the position of the discharge port. In the configurations shown in both figures, the side faces of the cylindrical body are concentrically formed to have small-diameter outlets 106, 2
Since only 06 is closed by the side plates 108 and 208 that are opened in the cylinder center, it is necessary to remove this side plate in order to adjust or replace the perforated plates 104 and 204 mounted inside the side plates 108 and 208, and maintenance is complicatedly lost. To do. Further, as a drawback of the cylinder core discharge method, the inner diameters of the hollow cylinders 101 and 201 and the discharge ports 103 and 2
Since it is unavoidable that a step D is generated between the inner diameter of 03 and the inner diameter of 03, the lower bottom portion of the cylindrical body is always placed in a condition that is difficult to discharge,
There is undeniable concern that some stagnation will occur. If the residence time is prolonged, it causes excessive pulverization and induces sludge formation.If the rapid discharge of added water is hindered, the impact force of the pulverization medium is reduced and the pulverization efficiency is significantly reduced. is there.

In order to solve the above problems, the present invention prevents clogging of slits more than ever, further promotes smooth slurry flow, and eliminates the fear of causing over-milling and reduction of milling efficiency. The purpose is to provide a wet ball mill having a structure.

[0010]

In a wet type ball mill according to the present invention, a crushed sand material M supplied with water from a supply port 2 provided at one side end of a rotating hollow cylinder 1 is previously crushed in a crushing chamber 3.
The crushed sand S is crushed by rolling and impact of the spherical crushing medium B charged in the hollow crushed medium B, and the crushed sand S is passed through a large number of slits 5 formed in the perforated plate 4 partitioning the other side end of the hollow cylinder 1. It is a type of discharging as a slurry, and particularly the slit 5
And a discharge space 7 in which a plurality of discharge ports 6 opening to the outer periphery of the cylinder are provided around the perforated plate 4 so as to be gradually expanded toward the cylinder center side. Is a structural feature.

The wet type ball mill according to the present invention has the above-described basic structure, and since the slits of the perforated plate are not parallel and gradually increase from the outer peripheral side of the perforated plate toward the cylinder center, the hollow cylinder rotates. If the clogged slit is located at the top, the drop force due to its own weight directly acts on the crushed sand adhering due to the vibration caused by the falling impact of the steel ball and the steel ball sandwiched due to wear reduction, and at this point the slit expands downward. Since it is in an expanded state, it can easily drop in a free space and greatly promote the elimination of clogging. Moreover, at the top of the hollow cylinder, there is no crushing medium or crushed material around the perforated plate, and there is no obstacle that prevents falling, which is also a factor that promotes the promotion of the action.

Further, a plurality of discharge ports 6 are opened on the outer peripheral surface of the discharge space 7 that seals the side end of the hollow cylinder 1, and the discharge port 6 which has rotated to the lowest portion as the hollow cylinder 1 rotates is discharged most easily. Therefore, like the conventional discharge port that opens at the center of the side plate, the product crushed sand stagnates at the bottom of the hollow cylinder 1 and is over-crushed, or the discharge of added water is delayed in the crushing chamber and the crushing impact force is increased. The fear of killing is completely eliminated.

When a specific embodiment is added to this basic structure, more peculiar actions and effects are added. That is, if the crushing chamber 3 is divided by tilting away from the supply port 2 toward the cylinder center from the outer peripheral side of the porous plate 4, the crushing medium B is lifted by the rotation of the hollow cylinder 1, When it collides with the slit 5 of the plate 4, the perforated plate 4
Is inclined, the component force F perpendicular to the perforated plate 4 as shown in FIG.
Acts to push out the clogging-caused deposits, so that a unique action for further preventing clogging appears.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to the drawings. FIG. 1 (a) is a front sectional view summarizing the whole wet ball mill according to the present invention, and FIG. 1 (b) is a side view of a perforated plate 4 which is a main part thereof. The horizontal cylinder 1 supported horizontally is rotatably installed by a drive mechanism (not shown). The rotating means may be a rotating shaft that is supported from both ends via trunnions, or may be a method of horizontally supporting and rotating with two pairs of wheels connected to a drive source. A supply port 2 for supplying the crushed sand material M is provided at both ends of the hollow cylinder 1, and enters the hollow cylinder 1 through a central opening of one side plate 8.

At the same time as the crushed sand raw material M, additional water is injected from a water supply port (not shown), and the crushing medium B (steel ball), the crushed sand raw material M, and water, which are preliminarily charged in the crushing chamber 3 as the hollow cylinder 1 rotates. The integrated fluid develops a cascading motion in which centrifugal force and gravity are combined, during which the crushed sand raw material M is crushed by the falling impact force and rolling of the crushing medium B, and the crushed sand raw material M moves toward the other end in the hollow cylinder. Flow. The amount of water added is an indispensable factor for maintaining this fluidity, but if it is too large, the impact force of the crushing medium B falling is alleviated and the crushing effect is lost, so this is an important know-how.

A plurality of discharge ports 6 are opened on the outer periphery of a discharge space 7 formed by closing the other end of the hollow cylinder 1 with a side plate 8. If necessary, one of the holes may be used as a human hole, which is closed during operation so that a worker can directly sneak into the cylinder without removing the side plate 8 during internal inspection. As an embodiment of the perforated plate 4, a form in which a slit 5 is provided to divide into a plurality of fan-shaped plates as shown in FIG. 1B is suitable. In order to attach each porous plate 4 and synthesize it into one annular plate, an attachment frame 9 (shown by a chain line) fixed to the outer peripheral surface of the hollow cylinder 1 or an inner surface liner (not shown),
The perforated plates 4 are fixed by a connecting frame 10 that connects them.
The connection frame 10 also serves as a communication hole that connects the discharge space 7 and the crushing chamber 3, and inspection and maintenance personnel enter the discharge space 7 through the above-mentioned human hole, then pass through the connection frame 10 and enter the crushing chamber 3. You may make it enter.

One of the major features of this embodiment is the shape of the slit 5 of the perforated plate 4. That is, as shown in FIG. 1 (b), since the mesh width enlarged toward the cylinder center side is formed, the adhered substances clogging the slits, the fitted steel balls, etc. are separated by vibration. The operation of facilitating the operation is remarkably promoted, and the operation with less clogging naturally ensures the accurate particle size distribution of the product crushed sand and induces a great effect in terms of quality improvement.

In the method of discharging the product crushed sand S from the closed outer peripheral surface of the discharge space 7, the outermost end of the slit 5 of the perforated plate 4 can be opened close to the inner peripheral surface of the hollow cylinder. The product and crushed sand rapidly pass through and are discharged from the bottom of the discharge space to the outside of the cylinder. Since there is no stagnation or clogging, there is no excessive crushing or buffering action, and the sand-making action with stable quality efficiently continues.

FIG. 2 shows another embodiment of the present invention, in which the slits 5a of the perforated plate 4a do not necessarily have to be formed in a uniform radial pattern toward the cylinder center, and the slits 5a gradually increase toward the cylinder center side. This is an example showing that it is enough if the eyes are wide. In any case, the purpose is achieved if there is a free space in which the clogging deposits are automatically dropped by the vibration from the slit rotated to the vicinity of the apex of the hollow cylinder 1.

FIG. 3 shows still another embodiment, in which the perforated plate 4 is inclined in the direction away from the supply port 2 toward the cylinder center, and the discharge space 7 having the narrowest cross section at the cylinder center is formed. Is. As already mentioned, clogging is prevented by the principle shown in FIG. Further, when the slanted porous plate 4 is located at the top, crushed sand and steel balls B that have entered the slits.
Can easily fall into the crushing chamber 3 due to its own weight, so that it can better prevent clogging.

[0021]

[Example] 5 mm generated in the production process of a crushed stone factory
The following fine particles were used as a raw material and pulverized using the wet ball mill shown in FIGS. 1 to 3 to produce a crushed sand slurry, and water was separated from this slurry to obtain a product crushed sand. The average mesh width of the slits of the perforated plate is about 3 to 4 times larger than the maximum grain size of the product, and when the maximum grain size is 5 mm, the average mesh width is 15 to 20 mm. The diameter of the steel ball is often determined based on the raw material and the grain size of the product.
It is often 0 to 60 mm.

The above-mentioned raw material was measured in accordance with the regulations of "JIS A 5005 Crushed stone for concrete and crushed sand", and the actual rate of particle size judgment was about 51% (standard value was 53%), and the particle size distribution was as shown in FIG. Although the upper limit of the standard was slightly exceeded, as a result of treatment with the wet ball mill according to the present invention, the actual particle size determination rate of the obtained product crushed sand was improved to 58%.
The particles were sized so as to have an ideal particle size distribution located at the center of the upper and lower limits of the IS standard. In addition, when the slits were examined for clogging after the operation was completed, it was suggested that the clogging was far less than the slits in the perforated plate conventionally used in the prior art, which greatly contributed to the formation of a stable particle size distribution. Was there.

[0023]

As described above, the wet ball mill according to the present invention has a method in which the crushed sand raw material is supplied from one end of the hollow cylinder and only the water and the product crushed sand are discharged from the porous plate on the other end side, which is a predominant porous plate. The effect of automatically eliminating the clogging of the slit is extremely remarkable. As a result, it is possible to eliminate the adverse effects on the yield and quality of the product crushed sand such as sludge caused by over-milling, and also to improve the workability in combination with the improvement of the crushing efficiency associated with rapid discharge. Appear.

[Brief description of drawings]

FIG. 1 is a front sectional view (A) of a whole wet type ball mill according to an embodiment of the present invention and a side view (b) of a main part (a perforated plate).

FIG. 2 is a side view showing another embodiment of a perforated plate.

FIG. 3 is a front cross-sectional view of an entire wet type ball mill showing another embodiment of the present invention.

FIG. 4 is a partial cross-sectional view explaining the operation of the embodiment.

FIG. 5 is a particle size distribution chart of crushed sand showing the results of carrying out the present invention.

FIG. 6 is an overall front sectional view showing a conventional technique.

FIG. 7 is a front sectional view (a) and a side view (b) of a main part showing another conventional technique.

[Explanation of symbols]

1 hollow cylinder 2 supply port 3 crushing room 4 Perforated plate 5 slits 6 outlets 7 discharge space Raw material for crushed sand B grinding media S product crushed sand

Claims (2)

[Claims] 1. Rolling of a spherical grinding medium B charged in advance in a grinding chamber 3 with a crushed sand material M supplied together with water from a supply port 2 provided at one side end of a rotating hollow cylinder 1. The product is crushed by impact and passed through a large number of slits 5 formed in a perforated plate 4 partitioning the other side end of the hollow cylinder 1 to produce a crushed sand S product.
In a wet type ball mill that discharges the slurry as a slurry, the slits 5 are formed so as to gradually expand the mesh width toward the cylinder center side, and a plurality of discharge ports 6 that are open to the outer periphery of the cylinder with the porous plate 4 therebetween. A wet ball mill, characterized in that a discharge space (7) is formed around the core. 2. The wet ball mill according to claim 1, wherein the perforated plate 4 is formed so as to be inclined in a direction away from the supply port 2 toward the cylinder center.