JPH04338245A - Vertical roller mill and method for grinding water granulated slag - Google Patents

Abstract

PURPOSE:To make possible the stably continuous operation of a mill by removing materials piled up on a grinding table by means of the blowing of a high pressure materials while the mill is in operation. CONSTITUTION:An introducing pipe 17 to insert a device 18 (e.g. 'Atumat gun(R)') which blows off a high pressure fluid in the center of the grinding table 2 is provided. By means of this device 18, when a material (e.g. water granulated slag) is stayed and piled on the grinding table 2, it is removed by blowing the high pressure fluid. Coonsequently, the operation of the vertical roller mill is made stably continuous.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical roller mill suitable for crushing granulated slag and a method for crushing granulated slag.

0002

[Prior Art] Granulated slag is water-cooled and crushed blast furnace slag, which is a by-product when producing pig iron in a blast furnace. It is used as a raw material for hard materials. When pulverizing granulated slag industrially, a tube mill or a vertical roller mill is used. Incidentally, since granulated slag is usually accumulated and stored in an outdoor yard and then transported and used as needed, it contains about 10% by weight of water when used. Therefore, when grinding with a tube mill that does not have a drying function, dry it before grinding. On the other hand, vertical roller mills can dry raw materials by blowing hot air from below the casing around the grinding table during operation, so there is no need to dry the raw materials in advance even when grinding raw materials containing moisture. It is said that

However, in a vertical roller mill, the raw material is pulverized only at the periphery of the top surface of the pulverizing table, and not at the center of the top surface of the pulverizing table. Therefore, if the vertical roller mill is operated continuously for a long time, the raw material will stay and accumulate in the center of the top surface of the grinding table. In particular, when a hydraulic raw material such as granulated slag is charged in a water-containing state and pulverized, the accumulated raw material will solidify. When this accumulation becomes severe, the distribution of raw materials on the grinding table becomes uneven, making the operation unstable, resulting in a decrease in grinding efficiency and an increase in power consumption. Traditionally, when such problems occurred, the mill had to be shut down to remove the accumulated material.

0004

SUMMARY OF THE INVENTION An object of the present invention is to provide a vertical roller mill capable of removing raw materials accumulated on a grinding table without stopping the operation of the mill. Also,
An object of the present invention is to provide a method for efficiently crushing granulated slag.

[0005]

[Means for Solving the Problems] The present inventor conducted research to solve the above-mentioned problems and found that a method of spraying high-pressure fluid is effective as a method for removing raw materials accumulated on the grinding table. The present invention was completed.

That is, the present invention comprises a vertical cylindrical casing, a grinding table located at the bottom of the casing, a motor that rotates the grinding table in a horizontal plane, and a motor located on the grinding table that rotates as the grinding table rotates. In a vertical roller mill that has a grinding roller that grinds the raw material put on the grinding table between it and the top surface of the grinding table,
This is a vertical roller mill characterized by having means for spraying high-pressure fluid toward the center of the grinding table. Furthermore, when pulverizing granulated slag using a vertical roller mill, the granulated slag deposited on the pulverizing table during operation of the mill is removed by spraying high-pressure fluid. It's a method.

The vertical roller mill of the present invention will be explained in detail below with reference to FIG. 1 showing an embodiment of the present invention. Note that the present invention is not limited to the embodiment shown in FIG. A crushing table 2 is located at the bottom of a vertical cylindrical casing 1. This crushing table 2 has a rotating shaft 3 extending downward from the center of the bottom surface. This rotating shaft 3 is connected to a motor 5 via a speed change gear 4. This motor 5
This causes the grinding table 2 to rotate in a horizontal plane. Between the periphery of the crushing table 2 and the casing 1, there is a ring-shaped blade 6 having an opening for blowing hot air into the space above the crushing table 2 from below the casing 1.

A plurality of crushing rollers 7 are provided on the crushing table 2 so as to be in contact with the top surface of the crushing table 2. This crushing roller has a rotating shaft 8 and rotates as the crushing table 2 rotates. The rotating shaft 8 of each crushing roller is connected to a bearing 9 and a hydraulic cylinder 10 so as to correspond to the vertical movement of the crushing roller 7.
It is connected to the foundation floor via. The raw material fed onto the grinding table 2 is crushed by being pressed between each grinding roller 7 and the grinding table 2, and is crushed into the casing 1 by hot air blown from the openings of the blades 6 around the grinding table.
It is blown upward inward.

[0009] Inside the casing 1 and above there is a rotating blade 11 for classification. This rotary blade 11 is linked to a motor 12 located at the upper part of the casing 1 via a cylindrical rotary shaft 13 and a speed reducer 14, and by rotating at high speed, the hot air blown from the opening of the blade 6 is generated. Of the pulverized raw materials that are blown up, the coarse powder is knocked off and only the fine powder is allowed to pass through. The fine powder that has passed through the rotary vane 11 is discharged from the outlet 15 in the ceiling of the casing. A chute 16 for inputting raw materials from the upper opening of the cylindrical rotating shaft 13.
is provided toward the center of the top surface of the crushing table 2.

An opening is provided in the side wall of the central portion of the casing, and an inlet pipe 17 for inserting a device for blowing high-pressure fluid is provided in this opening. Although the device for blowing high-pressure fluid may be installed all the time, it is preferable to use the device when blowing high-pressure fluid. An example of a device for blowing high-pressure fluid is an athumat gun 18, which is used to remove coatings from cement kilns. Achumat gun 18 is water pressure 3
It can be injected at about 00 to 600 kg/cm2.

[0011] When a vertical roller mill is operated continuously for a long time, raw materials may accumulate and accumulate in the center of the upper surface of the grinding table 2. However, in the vertical roller mill of the present invention, high pressure fluid is blown into the grinding table 2. By doing so, the deposited raw material can be removed. In particular, when grinding raw materials with hydraulic properties such as granulated slag, the accumulated raw materials may solidify due to moisture derived from the raw materials, which has an extremely negative effect on operational stability, grinding efficiency, etc. However, according to the present invention, it can be removed as appropriate even during operation of the mill.

0012

EXAMPLE Using the vertical roller mill shown in FIG. 1, granulated slag with a water content of 10 to 15% by weight was pulverized to produce granulated slag powder with a Blaine specific surface area of about 4000 cm2/g. First, pulverization was continued for 5 days without blowing in high-pressure fluid, and when the operation was stopped and the inside was observed, granulated slag was deposited to a height of about 700 mm and solidified in the center of the top surface of the pulverization table. Next, water was injected at a water pressure of 500 kg/cm2 using the Achumat gun 18 once every 8 hours for 15 minutes each time during the mill's operation period. No accumulation was observed.

[0013]

According to the present invention, even if raw materials accumulate and accumulate on the grinding table, they can be removed while the mill is in operation, so that the mill can continue to operate stably.

[Brief explanation of drawings]

[Fig. 1] A schematic cross-sectional view showing an outline of an embodiment of a vertical roller mill of the present invention.

Claims (4)

[Claims] Claim 1: A vertical cylindrical casing, a grinding table located at the bottom of the casing, a motor that rotates the grinding table, and a motor located on the grinding table that rotates as the grinding table rotates and connects with the top surface of the grinding table. A vertical roller mill having a grinding roller for grinding a raw material placed on a grinding table between the grinding rollers, the vertical roller mill having means for spraying high-pressure fluid toward the center of the grinding table. 2. When pulverizing granulated slag using a vertical roller mill, the granulated slag deposited in the center of the pulverizing table during operation of the mill is removed by spraying a high-pressure fluid. Method of crushing crushed slag. 3. The means for spraying high-pressure fluid toward the center of the grinding table is configured to spray water at a water pressure of 300 to 600 kg/c.
2. The vertical roller mill according to claim 1, which is an athumat gun that sprays at m2. 4. The method for pulverizing granulated slag according to claim 2, wherein granulated slag having a water content of 5% by weight or more is pulverized.