JPH067695A - Method for crushing material in rotary type crusher - Google Patents

Abstract

PURPOSE: To provide a pulverizing method for pulverizing materials with low energy consumption. CONSTITUTION: Materials, more preferably brittle materials are pulverized in a rotary type crusher 3. The crusher 3 has a material inlet 5, at least one accelerator, i.e., a rotor 11 as well as a housing 9 for housing a pulverizing chamber 10 and a material outlet 7. The materials to be pulverized are charged via the material inlet 5, are accelerated by the accelerator 11 and are ejected into a pulverizing chamber 10. The materials impinge on the particles of the materials and an impingement means including an impingement wall 10 mounted in the pulverizing chamber 10, by which the materials are pulverized and are discharged via the materials outlet 7. A certain amount of frictional grinding bodies are mixed with the materials to be pulverized, by which the pulverization of the material particles is accelerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a rotary crusher having a material inlet, a housing containing at least one accelerator and a crushing chamber, and a material outlet.
A method for grinding a material, which is preferably a brittle material. By this method, the material to be crushed is loaded through the inlet of the material, accelerated by an accelerator, ejected into the crushing chamber, other particles and / or impact means mounted in the crushing chamber. Crushed by colliding with and discharged through the material outlet.

[0002]

2. Description of the Related Art Examples of crushers of the type described above include Japanese Patent Publication No. 58-84053 and European Patent Application No. 166,6.
72, Danish patent application 459/88, German patent application 3,844,181 and 3,844,178, and British patent application 8,
No. 331,496.

An example of a well-known crusher of the type described above is also shown in FIG. 1 of the present application.

The main characteristic of a crusher of the type described above is that the particles of material to be ground are accelerated in a rotor and ejected from the roller, as shown in FIG. 1, and then individually at a uniform and high velocity. The particles or agglomerates of material that are jetted into the impingement collide with individual other particles, agglomerates or beds of material or impact means, which break the material into smaller particles.

The crushing force caused by collisions between particles depends on the inertial force of the ejected material particles, while the inertial force depends on the ejection velocity and the mass of the particles. The mass of the particles decreases in proportion to the cube of the diameter, but the cross-sectional area decreases in proportion to the square of the diameter, so the efficiency of the crusher or crusher decreases as the size of the material particles decreases. . The reason is that the cross-sectional stress at a given deceleration decreases in proportion to the particle diameter.

Therefore, a drawback associated with grinding materials in crushers of the type described above is that the fine material particles are not well ground. This drawback is compounded by the fact that the breaking strength of smaller particles is greater than the breaking strength of larger particles. The reason is that the particles are homogeneous and that the air flow acting on a single particle has a relatively high effect on smaller particles, which is generally the case for smaller particles. This means that the grinding efficiency is relatively low.

Finally, by using a crusher of the type described above alone, either increasing the speed of the rotor or passing the material through the grinding process several times, the material can be brought to the desired fine grain size without consuming too much energy. Until finally it is impossible to crush.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for crushing and finally milling a material in a rotary crusher which overcomes the above mentioned drawbacks.

[0009]

According to the invention, the above object is in a rotary crusher comprising an inlet for material, a housing for accommodating at least one accelerator and a crushing chamber, and an outlet for material. In grinding the material, which is preferably a brittle material, the material to be ground is loaded through the inlet of the material, accelerated by an accelerator and ejected into the crushing chamber to remove other particles and / or Alternatively, in a method of crushing by colliding with an impact means mounted in a crushing chamber and discharging through an outlet of the material, a certain amount of the grinding body is mixed in the material to be crushed. It is achieved by the method.

With this, fine particles can be finely pulverized by using a rotary type crusher, and the material is repeatedly pulverized as necessary to finally pulverize it to a desired grain size. In addition, it is possible to carry out such grinding with a considerably lower energy consumption compared to a crusher without grinding bodies. Therefore,
The cement clinker can be finally milled to the normally defined and well-known particle size of the final cement.

The reason is that the attrition bodies used in connection with the material particles to be ground have not only higher density and thus higher energy, but also higher strength properties, which In particular, all the energy imparted by the accelerator to the mixture of materials and to the attrition mass is used for grinding the material during the collision of the material with the attrition mass.

The use of grinding bodies having a higher density makes it possible to improve the above-mentioned effect, because the grinding bodies carry more energy when they are ejected from the accelerator. This is because the energy transferred to the material can be increased.

As an example showing that the efficiency of energy transfer to a material can be significantly increased by mixing the material with the attrition mass, for example, the mass of the material is 33 of the total mass supplied to the crusher. It should be noted that, when it accounts for%, the specific effect on the material is more than three times greater than the specific effect on the material when only the material to be ground is fed.

In order to maximize the effect of mixing the attrition mass with the material to be ground, while at the same time allowing to increase the mass flow through the crusher without increasing the volume flow, the grinding is It is preferred that the density ratio between the material to be ground and the mill is 1: 2 to 1: 4.

The mixture of materials and mills can be fed directly from the conveying device to the crusher, but it is preferable to feed the mixture via a dosing device in order to maintain a uniform feeding rate.

In most cases, it is necessary to pass the material through the process several times in order to final mill the material to the desired particle size. However, from the point of view of the economy of milling, it is not appropriate to reintroduce into the process a material that already has the desired particle size, and according to the invention, therefore, the mixture of milled material and milling mass is primary. Transport to separator unit or separator, in this separator unit,
A very coarse material part as well as a coarse part containing the grinding bodies,
The mixture is separated into a fine material portion, the coarse portion is returned to the crusher inlet and reintroduced into the crusher, while the fine portion is discharged.

The fine portion discharged from the primary separator unit is conveyed to the secondary separator unit and is classified into a final ground fine portion and an intermediate portion, and the final ground fine portion is the secondary portion. It is discharged from the separator unit and the intermediate part is preferably returned to the crusher for further grinding.

The abraded body wears out over time. Therefore, it is necessary to remove the attrition mass from the attrition / separation circuit when it has worn down to a certain minimum dimension or less. At the same time, it is necessary to replenish with fresh grind to maintain a constant weight ratio between the material and grind in the mixture. Therefore, in the preferred embodiment, the attrition is preferably a detectable material such as a metallic material.

[0019]

The present invention will be described in detail below with reference to the drawings.

Referring to FIG. 2, there is shown a plant or apparatus 1 for final milling of material. This device comprises a rotary crusher 3 with an inlet 5 for material, an outlet 7 for an annular material and a housing 9 with an impingement wall 10.
And a rotor 11. The device 1 further comprises a primary separator in the form of an air classifier 13 and a secondary separator 1
9 and the primary separator includes a duct 1
Carrier gas is supplied via 5. The primary separator is a material outlet 1 for the separated or screened rough portion.
Have 7. The secondary separator separates the very finely ground, final milled portion and discharges this portion via duct 21.

The mixture composed of the ground material and the material to be ground is loaded via duct 23 and enters crusher 3 via inlet 5. The actual crushing takes place in this crusher. The mixture of the crushed material 3 and the ground material is passed from the crusher 3 through the outlet 7 to the primary separator 1
3, and in this primary separator, the mixture is separated into fine and coarse parts by gas separation or air separation. The fine portion is raised by the carrier gas through the device 1 to the secondary separator 19, and the coarse portion is passed through the outlet 17 and the conveying means (not shown) and is returned via the duct 23 into the crusher.

In the separator 19, the loaded material is classified into a final ground fine portion and an intermediate portion, and the final ground fine portion is discharged from the duct 21 by the carrier gas, while , The intermediate part is returned from duct 25 to the crusher via duct 23, or the material inlet 5 via duct 26.
Will be returned directly to.

[Brief description of drawings]

FIG. 1 is a side elevational view showing a known rotary crusher.

FIG. 2 is a side elevational view showing a grinding device for carrying out the method of the invention.

[Explanation of Codes] 1 crusher 3 crusher 5 material inlet 7 material outlet 9 housing 10 crushing chamber 11 rotor (accelerator) 13 primary separator unit 19 secondary separator unit

Claims (6)

[Claims] 1. A rotary crusher comprising a material inlet (5), a housing (9) containing at least one accelerator (11) and a grinding chamber (10) and a material outlet (7). 3) In a method for grinding a material, preferably a brittle material, said material to be ground is introduced via said material inlet (5) and accelerated by said accelerator (11). An outlet (7) of the material, which is jetted into the crushing chamber (10) and crushed by colliding with particles of another material and / or impact means mounted in the crushing chamber (10)
The material to be crushed, which is discharged via a method, is admixed with an amount of attrition mass. 2. Method according to claim 1, characterized in that the attrition mass comprises a detectable material, preferably a metallic material. 3. Method according to claim 1, characterized in that the weight ratio between the material to be ground and the attrition is 1: 2 to 1: 4. 4. A method according to claim 1, characterized in that the mixture of material and grinding bodies is fed to the crusher (3) via a dosing device. 5. The method according to claim 1, wherein the mixture of the material to be ground and the attrition mass is conveyed to a primary separator unit (13), where the material A coarse part and a coarse part containing the attrition, and a fine part of the material, the coarse part being returned to the crusher inlet (5) and reintroduced into the crusher (3). Meanwhile, the fine portion is discharged from the primary separator unit. 6. The method according to claim 5, wherein the fine portion from the primary separator unit (13) is conveyed to a secondary separator unit (19), where the final milled fine portion. And an intermediate portion, and the final finely ground portion is discharged from the first separator unit, and
Method, characterized in that said intermediate part is returned preferably for further grinding in said crusher (3).