JPH07256139A - Crushing control method - Google Patents

Abstract

PURPOSE:To reduce the crushing cost in a finishing stage by supplying a material to be crushed from the upstream side of a crusher, classifying the material into a material to be coarsely crushed and a material to be finely crushed, evaluating both classified materials and controlling the crushing based on the evaluation. CONSTITUTION:The cement material 10 of a cement producing equipment is firstly burned in a burning stage 20, and a cement clinker is formed as an intermediate product 30. The clinker is then crushed in the succeeding finishing stage 40 into the end product 50 which is shipped. In this case, the cement clinker as the intermediate product 30 is sampled as a material 1 to be crushed from the upstream side of the crusher in the finishing stage. The material 1 is classified into the material to be coarsely crushed and a material to be finely crushed, and the crushability of the material 1 is evaluated 60 with respect to both classified materials. The crushing in the finishing stage 40 is controlled based on the evaluation 60. Consequently, the crushing cost is reduced in the stage 40. Namely, the crushability of the material 1 is precisely evaluated, and optimum crushing conditions, etc., in the actual process are set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling pulverization of a mineral material (hereinafter referred to as crushed material) such as a cement clinker.

[0002]

2. Description of the Related Art In the industries handling various powders such as chemical industry and mining industry, crushing plays an extremely important role. For example, in the cement industry, the power cost required for grinding in the cement finishing process occupies a considerable portion of the direct manufacturing ratio, and reduction of this is one of the major problems. Therefore, various improvements have been made to the crusher, classifier, etc., and considerable results have been achieved.

On the other hand, the grindability of the crushed material, for example, the grindability of cement clicker, depends on the raw material conditions (minerals, chemical components, fineness), firing conditions, cooling conditions, etc. Quantity and distribution, glass phase content, mineral composition,
The morphology, size, crystal structure, etc. of minerals are not uniform, and even the same clinker varies considerably. If the grindability of this crushed material can be accurately measured and the crushing conditions and the like can be determined accordingly, it can greatly contribute to the reduction of power consumption.

Conventionally, as a material showing the pulverizability of crushed materials,
There are those that measure easiness of crushing (crushing ability) and those that measure crushing difficulty (crushing resistance), and various methods have been proposed. A typical one is the crushing work index of Bond, and the detailed test method is JIS, M
4002. This crushing work index expresses the crushing resistance of the crushed material obtained by measuring the crushing work amount required for crushing to a predetermined fineness, and is widely used as a basis for designing the crushing circuit, and also for the on-site crusher. From the operation results, calculate the crushing work index by a formula,
The difference from the measured value in the test mill is used as an operation guideline of the on-site crusher as a difference in the mechanical efficiency of the on-site crusher.

[0005]

As described above, the crushing work index has great practical value, but in an actual on-site process, it depends on the crushability of the crushed material evaluated by the crushing work index. Although the amount of crushed material charged to the crusher can be controlled, it cannot be linked to actions such as positively determining the crushing conditions on the crusher side according to the crushability of the crushed material. Therefore, this could not be utilized for direct power reduction.

Further, the crushing work index may be required to be measured using considerable labor and time and a large amount of crushed material in addition to complicated experimental conditions. Some indexes have been proposed which indicate the grindability corresponding to the desired product particle size. For example, the pulverizability of cement clinker is expressed by expressing the Blaine value (specific surface area) after pulverizing a pulverized material under the same conditions for a certain period of time and the energy consumption required to obtain a predetermined Blaine value as a pulverizability index. In each case, the crushed material is crushed all at once up to the Blaine value corresponding to the desired product particle size, and the crushability is evaluated. Cannot be used for.

In view of the above-mentioned circumstances, the present invention accurately evaluates the pulverizability of the crushed material and links it to the setting of the optimum pulverization conditions in the actual process, etc., so as to reduce the production cost of the powder. The purpose is to provide a method.

[0008]

In order to achieve the above-mentioned object, the crushing control method of the present invention collects a crushed material from the upstream side of a crusher, and crushes the crushed material into fine crushability and fine crushability. Controlling the crusher by individually evaluating the crusher (Claim 1), collecting crushed material from the upstream side of the crusher, and crushing the crushed material with the crushable material evaluation crushable material and the crushed material. Finer pulverizability than fine crushing material The particle size of the crushable material is adjusted and crushed under predetermined conditions, and the particle size characteristics of the crushed product are measured. And controlling the crusher by separately evaluating the crushability and the fine crushability (Claim 2), the crusher comprises a vertical roller mill, and controls the roller pressure or the table rotation speed of the vertical roller mill. (Claim 3), the crusher comprises a high pressure roll press mill, Controlling the pressing force or the number of revolutions of the pressure roll press mill (Claim 4), the crusher consisting of a ball mill, and controlling the amount of crushed material passing through the ball mill (Claim 5), and the crusher performing preliminary crushing. It comprises a machine and a ball mill (claim 6).

[0009]

The crushed material is subjected to a crushing test under predetermined conditions in the coarse crushing area and the fine crushing area, and the crushability of the crushed material in each area, that is, the crushability and the fine crushability are determined. The pulverizability of crushed material often conflicts between the coarse crushing area and the fine crushing area,
By individually evaluating the obtained pulverizability and fine pulverizability, it becomes possible to set the optimal pulverization conditions in the actual process, and effective pulverization control can be performed.

[0010]

EXAMPLE An example of the present invention will be described below mainly using a cement clinker as an example. In FIG. 1, the cement raw material 10 prepared by mixing limestone, clay, silica stone, iron raw material, etc.
Kiln with suspension preheater (SP, NSP)
A cement clinker as an intermediate product 30 is generated in a firing process 20 equipped with a cooler, etc., and then, in a cement finishing process 40 equipped with a crusher, a classifier, etc., crushed by adding gypsum and the like, and shipped as a final product 50. To be done. In such a general cement manufacturing facility, the cement clinker which is the intermediate product 30 is collected as the crushed material 1 on the upstream side of the crusher in the finishing step 40, and the crushability of the crushed material 1 is roughened as described later. Individual evaluation of crushability and fine crushability 6
0. Based on the crushability evaluation 60 of the crushed material 1, the arrow A
As shown in (1), the crusher in the finishing step 40 is controlled, for example, the roller pressure or table rotation speed of a vertical roller mill or a high-pressure roll press mill, or the amount of crushed material passing through the mill in a ball mill is controlled. Thus, the crushability evaluation 60 makes it possible to reduce the cost of crushing in the finishing process 40.

Next, details of the crushability evaluation 60 of the crushed material 1 will be described with reference to FIG. The crushed material 1 such as cement clinker collected from the on-site crusher entrance is subjected to the crushability test 2
And subjected to the fine pulverizability test 3. In the crushability test 2 and the crushability test 3, the particle size adjusting means 4a and 4 are used, respectively.
b, weighing means 5a, 5b, crushing means 6a, 6b, and crushed amount particle size characteristic measuring means 7a, 7b are provided, and the evaluation unit 8 determines the crushability and fineness from the particle size characteristics of the crushed amount. The grindability is individually evaluated.

The particle size adjusting means 4a and 4b are the crushing means 6
The conditions for setting the most preferable crushed material particle size at the start of crushing in a and 6b to effectively perform the crushability test 2 and the crushability test 3 and minimize the test error. It consists of a crusher such as a jaw crusher and a roll crusher, and a sieve equipment. The grindability evaluation and fine grindability evaluation crushed material adjusted to a predetermined particle size by the particle size adjusting means 4a, 4b is weighed in a fixed amount by the weighing means 5a, 5b and supplied to the crushing means 6a, 6b. A batch type ball mill is preferably used as the crushing means 6a, 6b, and the weighed crushed material is crushed for a predetermined time or a predetermined number of times in a coarse crushing area and a fine crushing area, respectively, and then measured by the measuring means 7a, 7b. The particle size characteristics such as the amount passed through the sieve mesh and the Blaine specific surface area are measured. The evaluation unit 8 compares the particle size characteristics with the particle size characteristics of the reference sample measured in advance to individually evaluate the crushability and the fine crushability of the crushed amount. The test equipment may be used in both the crushability test 2 and the fine crushability test 3. For example, the crushing means 6a and 6b may be used in the same batch type ball mill.

The particle size at the start of crushing of the above-mentioned evaluation crushed material and the crushing conditions are determined in consideration of the actual results such as the inlet particle size and the outlet particle size of the actual on-site crusher. For example, in the case of a cement clinker, in the closed-circuit pulverization using a two-chamber ball mill and a classifier, the product grain size at the exit of the classifier is adjusted to 3000 Blaine specific surface area.
Approximately 3300 cm ² / g, crushing in the first chamber of the ball mill is assumed to be crushable, and crushing in the second chamber is assumed to be crushable, and predetermined test conditions are determined. That is, the crushable material evaluation crushing material is assumed to be crushed to the same extent as the ball mill first chamber, and the particle size at the start of crushing by the particle size adjusting means 4a is 20 mm or less, preferably 10
mm or less, and the particle size at the end of pulverization is about Blaine specific surface area of about 1500 cm ² / g or less, preferably 50.
The crushing time or the number of times of crushing is determined so as to be about 0 to 1000 cm ² / g.

The pulverized material for evaluation of fine pulverizability is adjusted to have a particle size at the start of pulverization of 2 mm or less, preferably 1.5 mm or less, and a grain size at the end of pulverization is a Blaine specific surface area 1500c.
m ² / g or more, preferably 1600 to 2200 cm
The crushing time or the number of times of crushing by the crushing means 6a is determined so as to be about ² / g. Further, a crushed material having a particle size at the start of crushing adjusted to 2 mm or less, preferably 1.5 mm or less, and a Blaine specific surface area crushed in the crushability test 2 of 500 to 10
When the crushed material of about 00 cm ² / g is mixed and adjusted to make the crushed material for evaluation of fine pulverizability, the influence of the crushability can be eliminated as much as possible. Naturally, the particle size at the end of pulverization varies greatly depending on the pulverizability, and may be set as a rough guide, and it also corresponds to the desired product grain size at the exit of the on-site classifier. Various settings can be made.

Next, a batch type test ball mill (diameter 400
mm × length 450 mm, rotation speed 57 rpm, ball filling rate 32.6%, ball diameter 50 to 17 mm), the crushability test of the cement clinker as the crushing material 1 was performed under the conditions shown in Table 1. Cement clinker has different crushing methods (A; ball mill with preliminary crusher, B; ball mill,
(C: Ball mill with a preliminary crusher) The cement crusher was sampled at the entrance of the on-site crusher of 3 factories and subjected to the crushability test, while the power consumption of the on-site crusher was measured as the actual operation data at the time of collecting the cement clinker. 3 to 5 show the relationship between the electric power consumption and the Blaine specific surface area or the amount passing through the 0.6 mm sieve mesh. Incidentally, the crushability test and the crushability test are the first chamber (crushability) and the second chamber (fine crushing) in closed circuit crushing consisting of a two-chamber type on-site ball mill and a classifier.
The conditions were set assuming clinker crushing in.

[0016]

[Table 1]

FIG. 3 shows a case where the clinker is crushed all at once up to the Blaine value corresponding to the desired product grain size of the conventional type, and the pulverizability is evaluated. As shown in FIG. 3, when the Blaine specific surface area expressed as the grindability index becomes higher (the grindability becomes better), the power consumption rate of each on-site crusher at each factory (A, B, C) increases. The crushability of cement clinker itself can be evaluated for the time being.

On the other hand, in the crushability test assuming crushing in the first chamber of the ball mill, as shown in FIG. 4, the 0.6 mm sieve mesh passing amount expressed as the crushability index becomes high ( If the crushability is improved), the power consumption per unit of the on-site crusher in factories A and B will decrease, but it will increase in factories C. Further, in the pulverizability test assuming pulverization in the second chamber of the ball mill, as shown in FIG. 5, when the Blaine specific surface area expressed as the pulverizability index becomes high (fine pulverizability improves), Contrary to the result of crushability test, factories A and B
The power consumption per unit of the on-site crusher in Japan has risen, and it has been decreasing in Factory C.

FIG. 6 shows the relationship between the Blaine specific surface area in the fine grindability test and the 0.6 mm sieve mesh passage in the coarse grindability test, which is a cement clinker that is well ground in the coarse grindability test. In the pulverizing property test, it is difficult to pulverize, and it can be seen that the crushability of the clinker and the pulverizing property are contradictory.

As described above, the crushability of the cement clinker is obviously different in each cement factory, and also varies greatly in the same factory. Moreover, the crushability and the fine crushability are contradictory, and at the site. Correspondence between crushability and fine crushability differs depending on the crushing method of the crusher. Therefore, although the crushability of the cement clinker itself can be evaluated by the conventional crushability evaluation method shown in FIG. 3, in order to correspond to this evaluation, for example, a proper crusher for burning easily crushable clinker. It cannot be tied to on-site actions such as determining raw material conditions, firing conditions, or grinding conditions according to the grindability of the clinker.

On the other hand, according to the present invention, by individually evaluating the crushability and the fine crushability of the clinker, it is possible to connect the clinker to the action on the spot according to the crushing method of the crusher on the spot. For example, referring to FIGS. 4 and 5, in factories A and B, the clinker crushability and the crushing ability of the on-site crusher are improved, and in plant C, the clinker crushability and crusher fine crushability,
By improving the fine crushing ability of the on-site crusher, etc., it can be linked to the on-site action that greatly contributes to the reduction of power consumption.

Various improvements in the coarse crushing ability or the fine crushing ability of the crusher can be made according to the crushing system of the crusher arranged in the finishing step 40. For example, when the crusher is composed of a ball mill and a preliminary crusher such as a vertical mill or a roll mill, the preliminary crusher and the fine crusher which are responsible for the coarse crushing part are used according to the crusher's crushability evaluation and fine crushability evaluation. Improve the ability of the ball mill to handle That is, the clinker with poor crushability controls the roller pressure or table rotation speed of the vertical mill or the pressure of the roll mill, and the clinker with poor crushability controls the flow control valve of the ball mill. .

Also, when a vertical roller mill, a high-pressure roll press mill, a ball mill, etc., as the crusher, is independently arranged in the finishing step 40, similarly, the clinker is evaluated for crushing property and crushing property. Then, the roller pressure of the vertical roller mill, the number of rotations of the table, the pressure of the high-pressure roll press mill, the amount of clinker passing through the mill of the ball mill, and the residence time are controlled to improve the coarse crushing ability or the fine crushing ability.

Although the crushing control method of the present invention using cement clinker as the crushing material has been described above, the present invention is not limited to this and can be applied to various mineral materials such as limestone and blast furnace slag. When evaluating the pulverizability of these various materials, the particle size and pulverization conditions of the evaluation crushed material are determined in consideration of the actual results such as the inlet particle size and the outlet particle size of the on-site crusher.

[0025]

As described above, according to the present invention, the pulverizability of the crushed material can be accurately evaluated by an extremely simple method, and the optimum crushing condition can be set based on this evaluation. It becomes possible and effective crushing control can be performed.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a crushability evaluation test of crushed material.

FIG. 3 is a diagram showing a relationship between an electric power consumption rate and a Blaine specific surface area in a conventional grindability test.

FIG. 4 is a diagram showing a relationship between an electric power consumption rate and a 0.6 mm sieve mesh passing amount in a crushability test based on the present invention.

FIG. 5 is a diagram showing the relationship between the electric power consumption rate and the Blaine specific surface area in the pulverization test according to the present invention.

FIG. 6 is a diagram showing the relationship between the Blaine specific surface area in the fine grindability test and the 0.6 mm sieve mesh passing amount in the coarse grindability test based on the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crushed material 2 Crushability test 3 Fine crushability test 4a Particle size adjusting means 4b Particle size adjusting means 5a Weighing means 5b Weighing means 6a Grinding means 6b Grinding means 7a Particle size characteristic measuring means 7b Particle size characteristic measuring means 8 Evaluation part 10 Cement Raw material 20 Firing process 30 Intermediate product 40 Finishing process 50 Final product 60 Grindability evaluation

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Claims (6)

[Claims] 1. The crusher is controlled by collecting a crushed material from an upstream side of the crusher and separately evaluating the crushed material into a crushability and a fine crushability. Crush control method. 2. A crushed material is collected from the upstream side of the crusher, and the crushed material is adjusted to a crushable material evaluation crushable material and a fine crushable material evaluation crushable material finer than the crushable material evaluation crushable material. The particle size characteristics of the crushed product are measured together with the respective crushed conditions, and the crusher is separately evaluated based on the particle size characteristics by separately evaluating the crushability and the fine crushability of the crushed material. A crushing control method characterized by controlling. 3. The crushing control method according to claim 1, wherein the crusher comprises a vertical roller mill, and the roller pressure or table rotation speed of the vertical roller mill is controlled. 4. The pulverization control method according to claim 1, wherein the pulverizer comprises a high-pressure roll press mill, and the pressurizing force or rotation speed of the high-pressure roll press mill is controlled. 5. The crushing control method according to claim 1, wherein the crusher is a ball mill, and the amount of crushed material passing through the ball mill is controlled. 6. The pulverization control method according to claim 1, wherein the pulverizer comprises a preliminary pulverizer and a ball mill.