JPH0859313A - Production of cement - Google Patents

Abstract

PURPOSE: To improve the easiness, economy and productivity in producing >=2 kinds of cements having a different composition by crushing and classifying a clinker of single composition. CONSTITUTION: Clinker and gypsum are supplied to a mill 3 respectively from a clinker silo 1 and a gypsum silo 2 and crushed at the same time. The crushed material is charged into a cyclone separator 5 through a bucket elevator 4 and preclassified into the coarse grain and small grain. The coarse grain is returned to the mill 3 through a return line 6, the small grain is air-floated into a small cyclone 7 and classified into the fine powder and fine grain, the fine powder is discharged from a discharge line 8 as product I. Meanwhile, the fine powder entrained by a gas and discharged from the cyclone 7 is collected in a bag filter 9 and discharged from an outlet 10 as product II. Product I is relatively rich in C2 S and C3 A and product II in C3 S and C4 AF, and a cement of desired composition is produced by mixing both products in a specified ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing cement, and more particularly to a method for producing cement having two or more different compositions from a clinker having a single composition.

[0002]

2. Description of the Related Art Cement, for example, Portland cement, which is a calcium silicate type cement, is a calcareous raw material (limestone) and a clayey raw material (clay, silica stone, iron oxide raw material).
It is manufactured by adding gypsum to the clinker obtained by mixing and firing and crushing.

This Portland cement includes ordinary cement, early strength cement, moderate heat cement, super early strength cement, sulfate resistant cement, etc., depending on their composition, each having its own characteristic properties, and depending on the application. Are used properly.

For example, the chemical analysis values and compound compositions of normal cement, early-strength cement, and moderate heat cement are as follows.

[0005]

[Table 1]

[0006] Conventionally, in order to manufacture such cements having different compositions, a method has been adopted in which different clinker raw materials are mixed so that each composition is adjusted, or various additives are mixed. ing.

[0007]

In the above conventional method,
Depending on the type of cement to be produced, a raw material blending device, a firing furnace, an additive material addition device, etc. are required, which is industrially disadvantageous.

That is, for example, in a firing furnace, when firing raw materials having different raw material compositions, as a matter of course, firing conditions are different, and if raw materials having different compositions are fired in the same firing furnace, the furnace wall is protected. The clinker layer that is present may fall off. Therefore, in order to manufacture cements having different compositions, manufacturing facilities corresponding to the respective cements are required, which is disadvantageous in terms of equipment cost, equipment space and the like.

Moreover, depending on the blending of the raw materials, the amount of heat consumed during firing increases, which causes a problem that fuel cost and refractory cost in the firing furnace increase.

Therefore, if two or more kinds of cements having different desired compositions can be easily produced from a clinker obtained by a predetermined composition mixture that can be fired with low fuel consumption, it is economical in terms of equipment and fuel consumption. Although it is considered that the productivity and productivity are significantly improved, conventionally, there has not been provided a method for producing cements having different compositions from a clinker having a single composition.

The present invention has been made in view of the above conventional circumstances, and provides a method for producing a cement, which can produce two or more kinds of cements having different desired compositions from a clinker having a single composition. With the goal.

[0012]

A method for producing a cement according to claim 1 is a method for producing a cement, which comprises a step of crushing a cement clinker, wherein the clinker is crushed and then classified to have a relatively large particle size. The present invention is characterized in that a grain fraction and a second grain fraction having a relatively small grain size are obtained, and each grain fraction is recovered as a product.

According to a second aspect of the present invention, there is provided a method for producing a cement according to the first aspect, wherein the obtained products are mixed in a predetermined ratio.

[0014]

As shown in Table 1, calcium silicate cement clinker is mainly composed of C ₃ S, C ₂ S,
It is composed of C ₃ A, C ₄ AF and the like. When milling this clinker, C ₃ S and C ₄ AF are C ₂ S and C
Easily crushed as compared to ₃ A. That is, the degree of easy pulverization differs depending on the constituent compounds.

In the present invention, by utilizing this difference in crushability, the clinker obtained by mixing and crushing the raw materials is classified by a classifier into a first particle having a relatively large particle size and a second particle having a relatively small particle size. Classify into the grain and. As a result, C ₃ S and C ₄ AF are provided on the second grain side, while C ₂ S is provided on the first grain side.
And a clinker enriched in C ₃ A is obtained. The same tendency can be obtained when classifying after adding gypsum to the clinker and crushing.

Conventionally, a clinker or a powder obtained by adding gypsum to a clinker and crushing with a cement crusher was used as it is as a cement, but in the present invention, such a powder is classified. By doing so, it is possible to obtain cements having two or more different compositions from the same clinker composition.

Therefore, with the same composition and the same equipment, cements having different compositions can be produced if desired,
In addition, a cement having a clinker composition that is difficult to fire can be easily obtained from a clinker composition that is easily fired.

According to the method of claim 2, by mixing the cements of different compositions obtained by the method of claim 1 in an appropriate ratio, it is possible to easily prepare cements of various kinds of composition depending on the purpose. It can be manufactured.

[0019]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of a crushing / classifying apparatus used in the method of the present invention.

In FIG. 1, the clinker and gypsum are supplied from the clinker silo 1 and the gypsum silo 2 to the mill 3 and simultaneously pulverized. This pulverized product is put into the cyclone separator 5 by the bucket elevator 4 and pre-classified into coarse particles and fine particles. The coarse particles are returned to the mill 3 by the return line 6. The fine particles conveyed by the air flow from the cyclone separator 5 and discharged are introduced into a small cyclone 7 and classified into fine powder (first particle portion) and fine powder (second particle portion), and the fine powder is The product I is taken out by the take-out line 8.

On the other hand, the fine powder discharged from the cyclone 7 by being entrained in the gas is collected by the bag filter 9 and taken out as the product II through the take-out line 10.

The cyclone 7 also serves as a classifier. For example, as shown in FIG. 2 (horizontal sectional view of the upper portion of the cyclone), a damper 7a is provided at the gas inlet of the cyclone 7. By adjusting the angle of the damper 7a and changing the wind speed in the cyclone, it is possible to adjust the classification points of the fine powder and the fine powder. The classification control may be performed by a method other than that shown in FIG. For example, as shown in FIG. 5, when a cyclone 50, a fan 51 and an air seal damper 52 are used,
The classification efficiency may be changed depending on the air volume of the blow-up fan.

According to the method shown in FIG. 1, the take-out line 8
With the fine powder taken out from the product cement I, which has a relatively large amount of C ₂ S and C ₃ A and a relatively small amount of C ₃ S and C ₄ AF, can be obtained, and the fine powder taken out from the take-out line 10 can be obtained. Therefore, the product cement II having a relatively large amount of C ₃ S and C ₄ AF and a relatively small amount of C ₂ S and C ₃ A, which has a different composition from the product cement I from the take-out line 8.
Can be obtained.

FIG. 3 is a system diagram showing another embodiment of the crushing / classifying apparatus used in the method of the present invention.

In FIG. 3, the clinker is crushed by a mill 20 and then classified by a classifier 21 into coarse particles (first particles) and fine particles (second particles). The coarse particles are supplied to the mill 22. Gypsum is also supplied to the mill 22 from a supply line 23, and C ₂ S and C
₃ Product cement A containing a large amount of A is produced.

The fine particles classified by the classifier 21 are mill 2
4, is pulverized and then introduced into the classifier 25,
Be classified. The classified fine powder is introduced into the mill 26.
Gypsum is also supplied from the supply line 27 to the mill 26, and the product cement B containing a large amount of C ₃ S and C ₄ AF is manufactured by simultaneous grinding.

The coarse powder classified by the classifier 25 is simultaneously ground together with the gypsum from the supply line 29 by the mill 28 to produce the product cement C having an intermediate composition between the product cement A and the product cement B. .

FIG. 4 is a system diagram showing another embodiment of the crushing / classifying apparatus used in the method of the present invention.

In FIG. 4, the clinker is crushed by a mill 30 and then classified by a classifier 31 into coarse particles (first particles) and fine particles (second particles). The fine grains are supplied to the mill 32. Gypsum is also supplied to the mill 32 from a supply line 33, and C ₃ S and C
₄ Product cement X containing a large amount of AF is manufactured.

The coarse particles classified by the classifier 31 are mill 3
4, after being pulverized, introduced into the classifier 35,
Be classified. The classified coarse powder is introduced into the mill 36.
Gypsum is also supplied to the mill 36 from the supply line 37, and the product cement Y containing a large amount of C ₂ S and C ₃ A is manufactured by simultaneous pulverization.

The fine powder classified by the classifier 35 is simultaneously crushed by the mill 38 together with the gypsum from the supply line 39 to produce the product cement Z having an intermediate composition between the product cement X and the product cement Y. .

Thus, according to the method of the present invention, the crushed clinker is classified to obtain C ₃ S, C ₄ A.
It is possible to manufacture a plurality of types of cement having different content ratios of a compound such as F that is easily crushed and a compound that is difficult to be crushed, such as C ₂ S, C ₃ A.

By mixing the thus produced cements having different compositions in an appropriate ratio, it is possible to easily produce a cement having any composition in the middle of these cement compositions.

In the present invention, the clinker composition as a starting material is not particularly limited and may be appropriately determined depending on the required cement composition, the cement manufacturing equipment to be used, etc.
Usually, a normal Portland cement composition, an early-strength Portland cement composition, a moderate heat Portland composition, a belite type clinker composition, etc. are preferable from the viewpoint of setting firing conditions and the like.

The method of the present invention is carried out in the same manner as the conventional method except that a step of classifying the cement clinker obtained by crushing is provided and a system for recovering each of the classified grain particles is provided. be able to. Further, the classification step may be performed before or after the cement clinker is mixed and ground with gypsum. Thus, by adjusting the classification point in this classification step, it is possible to easily obtain cement having a desired composition.

The present invention will be described more specifically with reference to the following examples.

Embodiment 1 In the apparatus shown in FIG. 1, the damper 7a of the cyclone 7 is used.
The installation angle was changed variously, and the particle fractions of various particle sizes were classified and collected. As a result, from the early-strength Portland cement clinker and the added gypsum fired with the following raw material blends, according to the particle size, the product cement No.
1 to 6 could be obtained.

Early strength Portland cement clinker raw material
Mixing and addition gypsum composition (parts by weight) Limestone: 74.4 Clay: 17.7 Silica stone: 2.3 Iron sulphide ore slag: 0.8 Added gypsum: 4.9

[0040]

[Table 2]

Example 2 In the apparatus shown in FIG. 1, from the same high-strength Portland cement clinker as in Example 1 and added gypsum, fine particles having a particle size of 6000 cm ² / g or more were recovered as product cement and Particle size as powder 6000 cm ² /
When less than g particles were recovered as product cement II,
The composition of each product cement is as shown in Table 3, and product cements having different compositions could be obtained.

[0042]

[Table 3]

Example 3 In the method shown in FIG. 3, from the same early-strength Portland cement clinker as in Example 1, coarse particles from the classifier 21 of 1000 cm ² / g or less were obtained.
As a coarse powder from No. 5, a grain fraction of 4000 cm ² / g or less was obtained, the rest was made into fine powder, and added gypsum was added to each to produce a product cement. As a result, as shown in Table 4, product cements A to C having different compositions could be obtained.

[0044]

[Table 4]

Example 4 In the method shown in FIG. 4, from the same early-strength Portland cement clinker as in Example 1, fine particles from the classifier 31 of 2000 cm ² / g or more were obtained, and the classifier 3 was used.
As a coarse powder from No. 5, a grain fraction of 2000 cm ² / g or less was obtained, the rest was fine powder, and added gypsum was added to each to produce a product cement. As a result, as shown in Table 5, product cements X to Z having different compositions could be obtained.

[0046]

[Table 5]

[0047]

As described above in detail, according to the cement manufacturing method of the present invention, cements having different compositions can be easily and efficiently manufactured with the same composition and the same equipment. Further, by adopting a clinker composition that is easy to burn, it is possible to easily and inexpensively obtain a cement having a clinker composition that is difficult to burn.

According to the method of claim 2, by mixing the cements obtained by the method of claim 1 in an appropriate ratio, it is possible to easily produce cements of various kinds of composition depending on the purpose. You can

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a crushing / classifying apparatus used in the method of the present invention.

FIG. 2 is a horizontal sectional view of a cyclone unit used in the apparatus shown in FIG.

FIG. 3 is a system diagram showing another embodiment of the crushing / classifying apparatus adopted in the method of the present invention.

FIG. 4 is a system diagram showing another embodiment of the crushing / classifying apparatus used in the method of the present invention.

FIG. 5 is a configuration diagram of a classification device adopted in the present invention.

[Explanation of symbols]

1 Clinker silo 2 Gypsum silo 3 Mill 4 Bucket elevator 5 Cyclone separator 7 Cyclone 7a Damper 20, 22, 24, 26, 28, 30, 32, 34, 3
6,38 mil 21,25,31,35 classifier

Claims (2)

[Claims] 1. A method for producing a cement having a step of crushing a cement clinker, after crushing the clinker, classifying the clinker into a first particle having a relatively large particle size and a second particle having a relatively small particle size. And a method for producing a cement, wherein each grain is recovered as a product. 2. The method for producing a cement according to claim 1, wherein the obtained products are mixed in a predetermined ratio.