JP2001334167A - Crusher - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To produce silica stone, which is a difficult-to-crush material, efficiently and stably over a long period of time with a single grinding device. SOLUTION: This is a pulverizing device for coarsely pulverizing silica using a vertical pulverizer and further finely pulverizing a part of the coarsely pulverized silica with a tube mill, and classifying the pulverized silica with the tube mill. Equipped with a classifier for separating fine powder,
By separating the fine powder from the silica stone pulverized by the tube mill by the classifier, the whole or a part of the silica stone pulverized by the tube mill and the fine powder separated and removed is re-pulverized by the tube mill, By suppressing the abrasion of parts generated in a vertical mill, silica stone, which is a difficult-to-mill material, is produced efficiently and stably over a long period of time with a single mill.

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 pulverizing silica, which is a difficult-to-pulverize material, and is particularly suitable for efficiently producing pulverized products having different particle sizes by extending the wear life of the pulverizing section of the pulverizer. To a grinding device.

[0002]

2. Description of the Related Art Conventionally, as a pulverizing apparatus for pulverizing silica which is a difficult-to-pulverize material, a pulverizing apparatus of a tube mill single system type using a tube mill alone has been often used. FIG. 4A shows an example of the pulverizing device. Although a detailed description is omitted, the crushing apparatus shown in FIG. 4A is arranged in a cylindrical tube of a rotating tube mill 10A by putting raw material silica as a material to be crushed into the cylindrical tube. This is a crushing device that crushes silica stone finely by the impact force and grinding effect of crushing balls. After the silica stone pulverized by the tube mill 10A is taken out of the tube mill 10A, it is classified by a classifier 53A to produce only silica stone smaller than a predetermined particle size. And pulverized again.

[0003] As another conventional pulverizer for pulverizing silica, a vertical pulverizer single system type pulverizer using a vertical pulverizer alone is known. FIG. 4 (2) shows an example of a vertical type pulverizer single system type pulverizer. Here, the vertical crusher 1B includes a rotary table (sometimes referred to as a table), a dam ring provided on the outer peripheral portion of the upper surface of the rotary table, and a plurality of dam rings provided on the outer peripheral portion of the upper surface of the rotary table. Crush roller, and presses the crush roller against the upper surface of the rotary table (sometimes referred to as crush pressure).
By doing so, the raw material supplied (sometimes referred to as charging) on the rotary table and retained on the rotary table by the dam ring is caused to bite between the peripheral surface of the grinding roller and the upper surface of the rotary table. It is a crusher for crushing.

The vertical pulverizer 1B shown in FIG.
Is a vertical pulverizer inside a classification device in which a classification device is arranged above a rotary table, and is sometimes referred to as an air-swept vertical pulverizer.
B blows most of the pulverized silica together with the gas blown from below in the vertical pulverizer 1B and reaches the separator above the turntable, and has a desired particle size (sometimes referred to as particle size). Only the raw material that has passed through is taken out of the pulverizer as a pulverized product, and the raw material that cannot reach the desired predetermined particle size and cannot pass through the separator falls to the upper surface of the rotary table and is pulverized again to obtain the predetermined particle size. This is a crusher that grinds raw materials repeatedly.

The vertical crusher 1B shown in FIG.
Is to drop a part of the large-diameter raw material that cannot be blown up by gas below the vertical pulverizer 1B, take it out through an outlet arranged at the lower part of the vertical pulverizer, and from the lower part of the vertical pulverizer. The raw material taken out is again put into a vertical pulverizer and pulverized again.

[0006] In the case of pulverizing a cement raw material or the like, a two-stage pulverizing apparatus is used in which a raw material primary-pulverized by a vertical pulverizer is secondarily pulverized by a tube mill. The vertical pulverizer used in this case is different from the above-mentioned air-swept type vertical pulverizer in that it does not include a separator or the like, and allows substantially the entire amount of the pulverized raw material to drop below the vertical pulverizer. It is common to use a vertical pulverizer of a type that can be taken out from an outlet disposed below the pulverizer.

Here, a vertical pulverizer of a type which is taken out from an outlet disposed below the vertical pulverizer is an efficient vertical pulverizer for coarsely pulverizing the raw material, and a tube mill is a pulverizer for removing the raw material. It is conventionally known that this is a pulverizing apparatus capable of efficiently pulverizing fine particles to a uniform particle size. That is, the two-stage pulverizing apparatus roughly pulverizes the raw material with a vertical pulverizer having high coarse pulverization efficiency (hereinafter, also referred to as primary pulverization), and then, uses the tube mill to pulverize the raw material. This is a pulverizing apparatus that efficiently performs fine pulverization (hereinafter, also referred to as secondary pulverization), and has high pulverization efficiency and is highly effective from the viewpoint of energy saving.

As an example of such a two-stage pulverizing apparatus, there is a pulverizing apparatus as shown in FIG. 1 of JP-A-63-20047. Most of the raw material is dropped from the outer surface of the rotary table and the inner surface of the casing to the lower part of the mill and taken out. The raw material taken out from the lower part of the pulverizer is refined by a classifier (to the product particle size). The raw material is separated and separated into coarse particles, and the refined powder is taken out as a product, and the entire amount of the coarse particles is sent to a tube mill of a secondary pulverizer for secondary pulverization. The raw material secondarily pulverized by the tube mill is conveyed by a bucket elevator or the like and sent to the classifier, where it is classified again or taken out as a product. Therefore, the classification device shown in FIG. 1 of the publication takes out the raw material reduced to the product particle size as the fine powder, and the classification point is set so that the raw material other than the fine powder can be taken out as coarse particles. I have.

[0009]

Here, a tube mill alone type pulverizer using a tube mill as shown in FIG. 4 (1) can produce a finely pulverized product having a uniform particle size. In the case of producing pulverized materials having different particle diameters, although having advantages, there is no other way but to change the diameter of the ball disposed in the cylindrical tube, and changing the ball diameter requires a lot of time and work. Therefore, it is not efficient, and it is not easy to produce pulverized materials having different particle diameters using a pulverizer using the tube mill. In addition, a pulverizing device using a tube mill is suitable for finely pulverizing raw materials due to its pulverizing principle of pulverizing an object to be pulverized with a ball in a cylinder, but is inefficient when performing coarse pulverization. There is such a problem.

On the other hand, when pulverized materials having different particle sizes are produced by a vertical pulverizer alone type pulverizer as shown in FIG. 4B, the separator disposed in the vertical pulverizer 1B is used. In order to change the classification point of the separator, it is necessary to change the classification point of the separator and to change the particle diameter of the product collected by the bag filter 45B.
It is necessary to change the rotation speed of the separator and the amount of gas blown. If the rotation speed of the separator and the amount of gas blown are changed and the particle size of the pulverized product collected by the bag filter 45B is changed, the pulverized product having a large particle size is changed to the bag filter 45B.
It is not efficient to collect gas by considering the energy consumption required for blowing gas. Further, in a vertical pulverizer, it is not easy to produce a finely pulverized product having a more uniform particle size than a pulverized product pulverized using a tube mill due to its structure. Therefore, even when the rotation speed of the separator and the amount of gas blown are changed and the particle size of the pulverized product collected by the bag filter 45B is changed, it is not possible to collect the finely pulverized product having a uniform particle size by the bag filter 45B. Have difficulty. For these reasons, it is difficult to efficiently produce pulverized materials having greatly different particle sizes with the vertical pulverizer 1B.

Further, in the pulverizing apparatus using the vertical pulverizer, when a hard-to-pulverize material having a high hardness is pulverized, abrasion of a rotary table, a pulverizing roller and the like is remarkably large. In particular, silica is mainly composed of silicon oxide (Si)
O ₂ ), it is extremely hard, and has a problem in that the rotating table and the crushing roller of the vertical crusher are severely worn during crushing, and the life thereof is extremely short. Therefore, for example, when a crushing device as shown in FIG. 4 (2) is used, it is necessary to replace the worn part (table liner, etc.) of the above-mentioned parts in the operation for 600 hours to 700 hours, and a stable operation is required for a long time. It is difficult to continue for a long time.

In the case where the above-mentioned conventional two-stage pulverizer is used, the classifier is set at a classification point so as to take out the raw material reduced to the product particle size as fine powder. Therefore, when producing pulverized materials having different particle diameters, it is possible to some extent by taking measures such as changing the classification point of the classifier, but it is possible to produce pulverized products having greatly different particle diameters. It is not structured.

[0013] Here, as the pulverized product using silica as a raw material, a pulverized product mainly having a particle size in a range of 2000 μm or more as a pulverized product having a large particle size (sometimes referred to as coarse powder); A pulverized product having a slightly larger particle size (sometimes referred to as a medium powder) is mainly a pulverized product having a particle size in the range of 100 μm or more, and a pulverized product having a slightly smaller particle size (sometimes referred to as fine powder). ) And a pulverized product mainly having a particle size in the range of 100 μm to 53 μm, and a pulverized product having a small particle size (sometimes referred to as fine powder), mainly having a Blaine value of 4000 to 5000 cm ² / g. There are many demands for crushed products in the size range. However, for the reasons described above, conventional pulverizers could not efficiently produce pulverized products having greatly different particle sizes. In addition, the Blaine value of the pulverized product is a numerical value generally used when evaluating the fineness of cement.

The present invention has been made in view of the above-mentioned problems, and particularly relates to the pulverization of raw materials such as crushed stones and the like. The present invention relates to a pulverizing device suitable for manufacturing.

[0015]

Means for Solving the Problems To solve the above problems, (1) A crushing device according to the present invention crushes a raw material between an upper surface of a rotary table and a crushing roller and arranges the raw material under the rotary table. A crusher for coarsely crushing silica using a vertical crusher that can be taken out from an outlet, and further finely crushing a part of the coarsely crushed silica by a tube mill, and classifying the silica crushed by the tube mill. A classifier that separates the fine powder from the silica crushed by the tube mill by the classifier, and returns the whole or a part of the silica separated and removed to the tube mill. And pulverizing again by the tube mill.

(2) The pulverizing apparatus according to (1), further comprising a classifying apparatus for further classifying the whole or a part of the silica stone which has been pulverized by the tube mill and from which the fine powder has been removed. Was separated, and the remaining portion excluding the fine powder was returned to the tube mill, and pulverized again by the tube mill.

(3) The pulverizing apparatus according to (1) or (2), further comprising a classifying apparatus for classifying a part of the silica stone coarsely pulverized by the vertical pulverizer, and taking out the intermediate powder by the classifying apparatus. The remaining portion from which the intermediate powder was removed was returned to the vertical pulverizer, and pulverized again by the vertical pulverizer.

(4) The pulverizing apparatus according to any one of (1) to (3), wherein a part of the silica stone coarsely pulverized by the vertical pulverizer is directly taken out as coarse powder. Is provided.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. 1 and 2 show an embodiment of the invention according to the present invention, and FIG. 1 is a conceptual diagram illustrating a configuration of a crusher. FIG. 2 is a sectional view of a main part of the vertical crusher. FIG. 3 is a conceptual diagram illustrating a crushed state of silica stone, and FIG. 4 is a reference diagram illustrating a conventional crusher.

The structure of the vertical crusher 1 used in the embodiment of the present invention will be described below with reference to FIGS. The vertical crusher 1 used in the present embodiment includes a rotary table 2 that is driven and rotated by an electric motor 2M via a speed reducer 2B installed below the crusher, and a rotary table upper surface that is an upper surface of the rotary table. A plurality (three in the present embodiment) of crushing rollers 3 are provided at positions that equally divide the outer peripheral portion of the 2A in the circumferential direction.

The crushing roller 3 is connected to a piston rod of a hydraulic cylinder 8 via an upper arm 6 rotatably mounted on a lower casing 1A by a shaft 7 and a lower arm 6A formed integrally with the upper arm 6. 9, linked to
By the operation of the hydraulic cylinder 8, the raw material supplied to the rotary table upper surface 2A is pressed in the direction of the rotary table upper surface 2A and rotated in accordance with the rotation of the rotary table upper surface 2A. It is structured to bite and pulverize between them.

Most of the raw material (sometimes referred to as a crushed product) that has been bitten by the rotary table upper surface 2A and the crushing roller 3 is provided around the outer edge of the rotary table upper surface 2A. The structure is such that the vehicle rides over the dam ring 15 and goes to an annular passage 30 (also referred to as an annular space 30) which is a gap between the outer peripheral portion of the rotary table upper surface 2A and the lower casing 1A.

Here, the pulverized product that has passed over the dam ring 15 and traveled to the annular passage 30, which is a gap between the outer peripheral portion of the rotary table upper surface 2A and the lower casing 1A, drops from the annular passage 30 and is therefore of a vertical type. It is taken out as a pulverized product from a lower outlet 34 arranged below the pulverizer 1. In the present embodiment, by blowing a small amount of gas from the gas inlet 33 below the vertical crusher 1,
The fine dust of the raw material floating in the vertical crusher 1 together with the gas is taken out from the upper outlet 39 above the crusher, and the fine dust of the raw material floating in the crusher is taken out. Is discharged to the outside of the pulverizer together with the gas as dust-containing gas.

Next, the pulverized product taken out from the lower outlet 34 of the vertical pulverizer 1 is transported by the bucket elevator 41 and can be introduced into the tube mill 10. The raw materials
After classifying with a classifier 53 to remove fine powder having a small particle size, the powder is again charged into the tube mill 10.

The classifier 53 includes a bag filter 45.
The exhaust fan 47 is connected via the, and by operating the exhaust fan 47 to exhaust air,
By suctioning the air of the classification device 53 with the exhaust fan 47, the fine powder in the classification device 53 is collected by the bag filter 45 and can be taken out as a product (4) which is a crushed product having a desired particle size. . In the present embodiment, the bag filter 45 is provided via the classifier 53.
The particle size of the fine powder collected by
It was a pulverized product having a size in the range of 00 to 5000 cm ² / g. However, the particle size of the fine powder collected by the bag filter 45 via the classification device 53 is not limited to this, and is mainly in the range of several hundred μm or less suitable for pulverizing and manufacturing with a tube mill. Good if it is a crushed product.

Next, in the embodiment of the present invention, a part or the whole of the pulverized product obtained by removing fine powder from the pulverized product obtained by pulverizing the tube mill 10 is supplied to the classifier 52. 1 was connected to a raw material pipe by a method shown as an example, and a switching damper D1 was arranged in the raw material pipe. Therefore, if necessary, the damper D1
By switching the above, a part or all of the pulverized product from which the fine powder has been removed can be put into the classifier 52, and the pulverized product from which the fine powder has been removed can all be put into the tube mill 10. It has become.

Here, in the present embodiment, the classifying device 52 is adjusted so that fine powder having a slightly smaller particle size can be taken out, and the product (3) which is a crushed product taken out through the classifying device 52 is: The classification point of the classification device 52 was adjusted so that the pulverized product had a particle size mainly in the range of 100 μm to 53 μm. However, the particle size of the product (3) taken out through the classification device 52 is not limited to this, and is a pulverized product having a particle size within a range suitable for pulverization and production by a tube mill. It is sufficient that the diameter of the fine powder to be collected by the bag filter 45 through the main filter 53 is larger than the main particle diameter.

Therefore, in this embodiment, a part or all of the raw material pulverized by the tube mill 10 is put into a classifier 52 and classified to remove fine powder from the raw material pulverized by the tube mill 10. The fine powder taken out by the classifying device 52 is classified twice by the classifying device 53 and the classifying device 52 so that the fine powder can be taken out. Subdivision can be taken out as a good product (3) having a narrow particle size distribution and a sharp particle size distribution.

Further, in the embodiment of the present invention, in order to allow the pulverized product pulverized by the vertical pulverizer 1 to be put into the classification device 54, the raw material pipe is connected by a method as shown in FIG. Connected. In addition, a switching damper D2 is disposed in the raw material pipe, and a part of the pulverized product pulverized by the vertical pulverizer 1 can be introduced by appropriately switching the damper D2 as necessary. It has a structure that can be charged to 10.

Therefore, in the embodiment of the present invention, a part of the raw material pulverized by the vertical pulverizer 1
4, the pulverized product classified by the classifier 54 is turned into a medium powder having a slightly larger particle size, and the product (2) is taken out. It has a structure that can be returned to the vertical pulverizer and pulverized again. In the present embodiment, the crushed product taken out through the classifier 54 has a particle size of mainly 100%.
Although the classification point of the classification device 54 is adjusted so that the pulverized product has a size in the range of μm or more, the invention is not limited to this.

Further, in the embodiment of the present invention,
A raw material pipe is connected by a method as shown in FIG. 1 so that a part of the silica stone roughly crushed by the vertical crusher 1 can be directly taken out as a product, and an outlet is provided at a tip thereof. . Here, a switching damper D3 is disposed in the raw material pipe, and the damper D3 is appropriately switched as necessary, so that part of the silica stone roughly crushed by the vertical crusher 1 can be directly taken out of the outlet as a product. Can,
Further, the silica stone roughly crushed by the vertical crusher 1 can be sent to the bucket elevator 41.

Therefore, the embodiment of the present invention has a structure in which part of the silica crushed by the vertical crusher can be taken out as a coarse powder having a large particle size as a product (1). . In the present embodiment, the number of rotations of the rotary table of the vertical crusher 1, the crushing pressure,
The particle size of the coarse powder is mainly 20 depending on the dam ring height and the like.
The size is adjusted so as to be a large pulverized product having a size of 00 μm or more, but is not limited thereto.

Next, an operation method of the pulverizing apparatus according to the present embodiment will be described with reference to FIG. Silica supplied from the raw material hopper 60 to the vertical grinder 1 (in the present embodiment, silica is 99% or more of SiO _{2 and} most of the remaining components are AlO ₂ ) The material is fed into the center of the upper surface 2A of the rotary table from above the upper surface 2A of the rotary table via a raw material charging chute 13 whose tip is directed toward the upper center of the upper surface 2A of the first rotary table. The introduced silica stone is rotated on the rotating table upper surface 2A, and moves to the outer peripheral portion of the rotating table upper surface 2A while drawing a spiral trajectory on the rotating table upper surface 2A by centrifugal force due to the rotation.
It is crushed by being caught by the rotating table upper surface 2A and the crushing roller 3.

Most of the crushed silica that has been bitten by the rotary table upper surface 2A and the crushing roller 3 passes over the dam ring 15 fixed to the outer peripheral edge of the rotary table upper surface 2A. The silica stone having passed over the dam ring 15 is discharged into an annular passage 30 between the outer peripheral surface of the turntable 2A and the inner peripheral surface of the casing.

As a result, most of the crushed quartz, which has flowed toward the annular passage 30, falls from the annular passage 30 into the lower casing 1A and is taken out from the lower outlet 17 disposed below the rotary table 2. Is done. Dust floating inside the vertical crusher 1 is taken out of the vertical crusher 1 as dust-containing gas together with air, collected and collected.

First, in the case of producing fine powder of silica in the pulverizing apparatus according to the present embodiment, the exhaust fan 47 is operated, and the air of the classification device 53 is sucked by the exhaust fan 47. In the present embodiment, the particle size in the classification device 53 is mainly 4
A pulverized product having a size in the range of 000 to 5000 cm ² / g can be pulverized, collected by the bag filter 45 and taken out as a product.

In the case where fineness is made of silica stone in the pulverizing apparatus according to the present embodiment, the damper D1 is appropriately switched, and a part or the whole amount of the raw material pulverized by the tube mill 10 is charged into the classifying apparatus 52. Then, the raw material from which the fine powder has been removed is further classified from the raw material pulverized by the tube mill 10, and a pulverized product having a particle size mainly in the range of 100 μm to 53 μm is taken out as fine powder.

Further, in the case where the silica powder is produced by the pulverizer according to the present embodiment, a part of the pulverized product pulverized by the vertical pulverizer 1 by switching the damper D2 is put into the classifier 54. Classify, the particle size is mainly 10
A pulverized product having a size of 0 μm or more is taken out as a medium powder, and the remaining portion from which the medium powder has been removed is returned to the vertical pulverizer and pulverized again.

In the case where coarse powder made of silica is produced by the crushing apparatus according to the present embodiment, a part of the coarsely crushed silica by the vertical crusher is directly used as a crushed product by appropriately switching the damper D3. By taking it out, it is taken out as coarse powder whose particle size is mainly in the range of 2000 μm or more.

In the pulverizer of the present invention, the classifier 5
The classification points 2, 53 and 54, the grinding conditions of the vertical grinding machine, and the switching of the switching dampers D1, D2 and D3 are used to change the size of coarse powder having a large particle diameter as shown in FIG. Even fine powder having a small particle size can be efficiently produced. In the embodiment of the present invention, the particle size of each pulverized product to be taken out is set to a particle size in a range which is often required as a pulverized product of silica stone, and the particle size is mainly in a range of 2000 μm or more. The pulverized product as coarse powder, the pulverized product having a particle size mainly in the range of 100 μm or more as a medium powder, the pulverized product having a particle size mainly in the range of 100 μm to 53 μm as a fine powder, Efficient silica can be pulverized by taking out the pulverized product having a Blaine value of the pulverized product mainly in the range of 4000 to 5000 cm ² / g as fine powder.

It is to be noted that, in the above-described process, when it is desired to change the particle size of the pulverized product in pulverizing silica as a raw material, the classification points of the classifiers 52, 53 and 54, the pulverization conditions of the vertical pulverizer, By changing the switching position of the switching dampers D1, D2, D3, it is possible to adjust the particle size of the pulverized product taken out there.

In particular, in the present invention, wear generated on a rotary table or a crushing roller of a vertical crusher is remarkably suppressed by the idea of using a two-stage crusher for crushing silica, which is a difficult-to-crush material. It has a remarkable effect. This is not only for the simple reason that high hardness silica accelerates the progress of the wear of the parts due to its hardness, but also in the conventional vertical mill alone system, silica is used in the vertical mill, It is necessary to grind repeatedly until the desired fine particle size is obtained, and this is largely due to the fact that the wear of the parts progresses by the number of times of the repeated grinding.

That is, in the case of pulverizing a normal material which is not high in hardness and can be pulverized immediately, if the number of repetitions of pulverization in the vertical pulverizer is small, for example, about four or five times, When crushing silica stone, which is a difficult-to-crush material, it is necessary to repeat the crushing many times, such as seven or eight times. The progress of the abrasion is substantially proportional to the number of repetitions of the pulverization in the vertical pulverizer, and the more the number of repetitions increases, the faster the abrasion proceeds.

Therefore, when crushing silica stone,
In the conventional vertical pulverizer alone type system, it is necessary to replace the wear and consumption part of the rotary table and the pulverizing roller in the operation for 600 to 700 hours, and it has been difficult to continue the operation for a long time. However, according to the present invention, by reducing the number of repetitions of crushing silica in a vertical crusher in which abrasion is a problem, the frequency of replacement of the part is reduced by significantly suppressing the wear of the part,
It is possible to continue driving for a long period of time, such as about 3 to 5 times the conventional one.

In the case of pulverizing a cement raw material or the like, the above parts are worn, but the number of repetitions of the pulverization is small. Therefore, the progress of the abrasion is slow. Long-term operation of several thousand to 10,000 hours is possible.

In this embodiment, the raw material pulverized in the present embodiment is substantially entirely silica, but is not limited to silica, and may be a mixture in which other minerals, earth and sand are mixed with silica. The effect is exerted if the rotation of the rotary table or the like is remarkably advanced due to the mixture.

Further, silica used in the present embodiment, although SiO ₂ was used more than a 99% into its components is not limited thereto, the main component is a SiO _2, with its components The effect is exhibited if the progress of wear of the parts is remarkable. Further, the definition of silica in the present invention includes not only what is generally called silica, but also what is mainly composed of SiO ₂ irrespective of whether or not it is generally called silica. In other words, the present invention is effective as long as the wear of the above-mentioned parts is remarkable due to the components during the pulverization by the vertical pulverizer 1.

As described above, in the pulverizing apparatus according to the present invention, especially when pulverizing silica stone, pulverized products having different particle sizes can be efficiently and stably produced.

[0049]

According to the first aspect of the present invention, unlike the case of pulverizing a cement raw material or the like, the concept of using a two-stage pulverizer for pulverizing silica, which is a hard-to-pulverize material, is used. Has the remarkable effect of remarkably suppressing the wear generated on the rotary table and the crushing roller of the vertical crusher, and is about three to five times as large as that of the conventional silica crusher system of the vertical crusher alone type. For a long time,
It is possible to continuously operate the grinding of silica stone.

In the second invention, the material obtained by removing the pulverized product having a smaller diameter than the raw material pulverized by the tube mill is further classified to obtain a pulverized product having a desired particle size. . Therefore, the pulverized product taken out by the classifier is classified twice by two classifiers having different classification points, and a good pulverized product having a narrow particle size distribution and a sharp particle size distribution is obtained.

In the third and fourth aspects of the invention, a classifier and a pulverized product outlet are provided at a position suitable for taking out a pulverized product having a large particle size or a pulverized product having a relatively large particle size. A pulverized product having a desired particle size can be efficiently taken out without excessively pulverizing the raw material.

[0052]

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a configuration of a crusher according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the vertical crusher according to the embodiment of the present invention.

FIG. 3 is a conceptual diagram illustrating a crushed state of silica stone according to the embodiment of the present invention.

FIG. 4 is a reference diagram illustrating a conventional pulverizer,
(1) is a tube mill alone system, and (2) is a vertical mill alone system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical grinder 2 Rotary table 2A Rotary table upper surface (liner sticking part) 2B Reduction gear 2M Motor 3 Grinding roller 10 Tube mill 35 Raw material inlet 39 Upper outlet 34 Lower outlet 45 Bag filter (collector) 47 Exhaust Fan 52 Classifier 53 Classifier 54 Classifier 60 Raw material hopper D1 Switching damper D2 Switching damper D3 Switching damper

Claims (4)

[Claims] The raw material is pulverized between a top surface of a rotary table and a pulverizing roller, and silica is coarsely pulverized using a vertical pulverizer capable of being taken out from an outlet disposed below the rotary table. A pulverizing device for further pulverizing part of the silica stone by a tube mill, comprising a classifier for separating the fine powder by classifying the silica stone pulverized by the tube mill,
The classifier separates the fine powder from the silica crushed by the tube mill, and the whole or a part of the silica that is separated and removed is returned to the tube mill, and is crushed again by the tube mill. And crushing equipment. 2. A classifier for further classifying the whole or a part of the silica stone which has been pulverized by the tube mill to remove the fine powder, further comprising a classifier for separating the fine powder by the classifier and removing the fine powder from the remaining fine powder. 2. The pulverizing apparatus according to claim 1, wherein the portion is returned to the tube mill and pulverized again by the tube mill. 3. A classifier for classifying a part of the silica stone roughly crushed by the vertical mill, taking out the middle powder by the classifier, and removing the remaining part after removing the middle powder to the vertical mill. 3. The crushing device according to claim 1, wherein the crushing device is crushed again by the vertical crusher as a returning structure. 4. The apparatus according to claim 1, further comprising an outlet for taking out part of the silica stone coarsely crushed by the vertical crusher as coarse powder. Crushing equipment.