JP2003313056A - Method of producing cement clinker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively utilize by-produced fine powder produced when an aggregate is recovered from concrete scrap. <P>SOLUTION: By-produced fine powder produced when aggregates B and D are recovered from a concrete lump A after heating treatment to 100 to 500° is introduced into a preheater 61 preheating a cement raw material by utilizing an exhaust gas from a rotary kiln 62 as a part of the cement raw material. Thereafter, the fine powder is introduced into the rotary kiln 62 and is fired. The by-produced fine powder can be fed to the bottom side of the rotary kiln 62. Or the by-produced fine powder of >90 μm can be fed to a pulverizing machine for pulverizing the cement raw material. <P>COPYRIGHT: (C)2004,JPO

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 a cement clinker using as a raw material for cement a fine powder produced as a cement raw material when an aggregate is regenerated from a concrete waste material generated by the dismantling of a concrete structure or the like. .

[0002]

2. Description of the Related Art In recent years, from the viewpoint of recycling resources, cement and aggregate have been reclaimed from concrete that is discarded during dismantling. In order to regenerate the aggregate, the waste concrete material is usually crushed into concrete lumps of a predetermined size, and then the lumps of concrete are supplied to a rotary tube mill for scouring. By this grinding treatment, each concrete lump is crushed and ground, so that it is possible to obtain a coarse aggregate or a fine aggregate from which the cement paste has been removed. At the same time, the crushed cement paste and the scraped off part of the aggregate are collected as by-product fine powder.

The recycled aggregate can be reused as an excellent aggregate of structural concrete. On the other hand, as for by-product fine powder, although it is used as a soil conditioner,
The development of further applications was desired.

Therefore, the present inventors have conducted extensive studies on the use of by-product fine powder, and have found that it can be effectively used for the production of cement clinker.

[0005]

The present invention has been made based on the above findings, and a cement clinker capable of effectively utilizing by-product fine powder generated when collecting aggregate from concrete waste. It is an object to provide a manufacturing method.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 provides by-product fine powder produced when aggregate is recovered from concrete lumps after heat treatment at 100 to 500 ° C. It is characterized in that it is introduced as a part of the cement raw material into a preheater that preheats the cement raw material using exhaust gas from the rotary kiln, and then introduced into the rotary kiln and fired.

The invention according to claim 2 is 100-500.
Characterized by introducing by-product fine powder generated when collecting aggregate from concrete lump after heat treatment at ℃ to the kiln end of the rotary kiln for firing cement raw material as a part of the cement raw material and firing in the rotary kiln I am trying.

According to a third aspect of the present invention, in the invention according to the first or second aspect, the fine powder produced as a by-product generated when the aggregate is recovered from the concrete mass after the heat treatment at 100 to 500 ° C. is classified, By-product fine powder having a particle size of 90 μm or less is introduced to the kiln side of the preheater or the rotary kiln, and by-product fine powder having a particle size of more than 90 μm is introduced as a part of the cement raw material into a crusher for crushing the cement raw material. Then, firing is performed in the rotary kiln through the preheater.

In the inventions according to claims 1 to 3 configured as described above, the by-product fine powder is finally introduced into the rotary kiln as a part of the cement raw material and fired in the cement clinker. Become. That is, since the by-product fine powder contains a large amount of quick lime (CaO) as a calcareous raw material and silicon dioxide (SiO ₂ ) as a siliceous raw material, tricalcium silicate (3CaO · SiO ₂ ) is produced by these reactions. And dicalcium silicate (2CaO ・ Si
O ₂ ) can be reliably generated. Therefore, the by-product fine powder generated when the aggregate is recovered from the concrete waste material can be effectively used as a cement raw material.

As the calcareous raw material, quick lime other than calcium carbonate (CaCO ₃ ) and slaked lime (Ca (O
Since H) ₂ ) is contained in a large amount, it is possible to suppress the emission of carbon dioxide (CO ₂ ) due to decarboxylation. Moreover, since the amount of heat required for decarbonation is unnecessary, it is possible to suppress the emission of carbon dioxide generated when burning the fuel. Moreover, since the fuel consumption can be reduced, the cost for cement production can be finally reduced. In addition, since SiO ₂ and Al ₂ O _{3 which} are usually supplied in large amounts from clay are included in the fine powder in a large amount, the amount of clay used is reduced, and as a result, the amount of heat required for dehydration of clay minerals is reduced. Therefore, this point also contributes to cost reduction. In addition, fine powder of 90 μm or more is 2
Since it is 0% or less and is sufficiently fine, it does not go through the raw material crushing step and reacts well with other raw materials even if it is directly introduced into the preheater, so it is necessary to perform crushing like ordinary cement raw materials. There is no. Therefore, also from this point, it is possible to reduce the cement production cost.

Further, in the invention described in claim 1,
Since the by-product fine powder is introduced into the preheater, even if the by-product fine powder may contain water, the by-product fine powder after removing this water and heating it to a predetermined temperature is used in the rotary kiln. Can be supplied to. Therefore, the cement clinker can be efficiently manufactured.

In the invention of claim 2, since the by-product fine powder is guided to the kiln side of the rotary kiln, the pressure loss of the preheater or the like is reduced and, for example, the power of the induction fan that sucks the exhaust gas from the preheater is reduced. In addition, the cement clinker can be fired more directly and in a shorter time. That is, by-product fine powder is 1
Since water and chemically bound water are removed by heating at 00 to 500 ° C., the cement clinker can be efficiently put into the kiln end of the rotary kiln and efficiently burned into a cement clinker in the rotary kiln.

According to the invention of claim 3, 90 μ
After pulverizing by-product fine powder of more than m by a crusher, it is supplied to the preheater, and by-product fine powder of 90 μm or less is introduced into the preheater or the kiln butt side of the rotary kiln. The finely pulverized by-product fine powder can be supplied. Therefore,
A cement clinker can be efficiently produced in a rotary kiln. In addition, since fine powder of by-product having a size of more than 90 μm is already finely pulverized before being put into the pulverizer, the energy required for the pulverization is reduced as compared with the case of pulverizing a normal cement raw material. Can be achieved. Therefore, the cement manufacturing cost can be reduced. This method is particularly effective when firing early-strength cement clinker or low-heat cement clinker, which is difficult to fire unless the raw material has a smaller particle size.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, a method for manufacturing a cement clinker according to a first embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram of a cement manufacturing facility for carrying out a method for manufacturing a cement clinker, and FIG.
FIG. 4 is a diagram showing an aggregate regenerating facility for recovering aggregate from a concrete waste material, and FIG. 3 is a diagram showing a fine powder classification treatment facility for classifying by-product fine powder generated in the aggregate regenerating facility.

In FIG. 2, reference numeral 1 is a filling type heating furnace for heating the concrete block A. This filling-type heating furnace 1 heats a concrete block A continuously supplied to the upper part of the cylindrical furnace wall 1a at a constant temperature for a predetermined time, and then a table feeder (not shown) from the lower part of the cylindrical furnace wall 1a. It is designed to be continuously discharged through. The heating is performed by supplying hot air generated by burning kerosene or the like from the periphery and the center of the lower position of the cylindrical furnace wall 1a and raising the inside of the cylindrical furnace wall 1a.

The concrete block A is obtained by crushing a concrete waste material generated by the dismantling of a concrete building into 20 to 40 mm by a crusher. Examples of this crusher include a jaw crusher that crushes concrete waste material by sandwiching it between fixed teeth and movable teeth, a hammer crusher that crushes concrete waste material using the impact force of a hammer that rotates at high speed, and a concrete waste material. A dry type such as a centrifugal crusher is used in which the concrete lumps A already existing in the surroundings are collided by being scattered at high speed by centrifugal force and crushed by the impact force at that time.

Further, the concrete mass A has a maximum size of 5
It is preferable that the material having a diameter of less than mm removed by a sieve is put into the filling type heating furnace 1. That is, 5 mm like this
By removing the concrete lumps A of less than, the flow of hot air upward in the vertical direction in the filling type heating furnace 1 is improved, and the concrete lumps A are heated to a uniform temperature. The heating temperature of the concrete block A is 10
It is preferable to set the temperature to 0 to 500 ° C., preferably 300 to 350 ° C. in order to efficiently remove the cement paste from the aggregate by the rubbing treatment in the coarse aggregate mill 2 and the fine aggregate mill 3 described later. In this embodiment, 300
It is set to ~ 350 ° C.

The reason why the temperature is set to 100 to 500 ° C. as described above is that, if the temperature is less than 100 ° C., the effect of weakening the cement paste in the concrete mass A is weak, and the cement paste or the like is often dehydrated. Because it takes time. Further, if the temperature exceeds 500 ° C., the coarse aggregate and the fine aggregate in the concrete block may be deteriorated or deteriorated. Considering this point, the actual heating temperature is preferably 300 to 350 ° C.

The concrete block A, which has been subjected to the heat treatment in the filling-type heating furnace 1, is sequentially sent to the coarse aggregate mill 2 and the fine aggregate mill 3 to be subjected to the grinding treatment.

The coarse aggregate mill 2 is of a double-drum type, and includes an outer drum 21, an inner drum 22 coaxially provided inside the outer drum 21, and an inner drum 22. And a plurality of fraying media 23 put in.

Each of the outer drum 21 and the inner drum 22 has a cylindrical outer peripheral wall, and the axes thereof are inclined obliquely downward from the supply port 22a side toward the carry-out ports 22b, 21a side. It is designed to rotate around. A plurality of through holes are formed in the inner drum 22, and a mesh portion 22c having a mesh size of about 4.5 mm is wound around the outer periphery of the through hole. The net portion 22c is adapted to sieve the mortar C having a size of 4.5 mm or less generated by the rubbing treatment in the inner drum 22 and move it to the outer drum 21 side. The grinding medium 23 is composed of steel balls having abrasion resistance, and is configured to separate the mortar C from the coarse aggregate B by crushing and grinding the concrete block A.

The supply port 22a is provided with a coarse aggregate mill 2
Is located inside the inner drum 22 at one end in the axial direction, and the carry-out port 22b is located inside the inner drum 22 at the other end in the axial direction of the coarse aggregate mill 2 and is another carry-out port. 21 a is located between the inner drum 22 and the outer drum 21 at the other end of the coarse aggregate mill 2 in the axial direction. Therefore, the concrete block A supplied from the filling type heating furnace 1 enters the inner drum 22 through the supply port 22a,
The coarse aggregate B that has been rubbed in the inner drum 22 is carried out from the carry-out port 22b and supplied to the fine aggregate mill 3, and the inner drum 22 and the net portion 22c are processed during the rubbed treatment.
The mortar C that has flowed out to the outer drum 21 side via the is carried out from the carry-out port 21a and supplied to the fine aggregate mill 3.

The fine aggregate mill 3 has a cylindrical outer peripheral wall,
The axis is rotationally driven around the axis in a state of being inclined obliquely downward from the supply port 3a side toward the carry-out port 3b side. The fine aggregate mill 3 uses the mortar C separated by the coarse aggregate mill 2 and the coarse aggregate B as a grinding medium. By this rubbing treatment, the cement paste is separated from the fine aggregate D in the mortar C by crushing and grinding.

Fine aggregate D produced in fine aggregate mill 3
And the coarse aggregate B is sent to the aggregate classifying equipment 4, and the fine aggregate D
And coarse aggregate B. The aggregate classifying equipment 4 is equipped with a vibrating sieve 41 having a mesh size of 5 mm. The aggregate that has passed through the vibrating sieve 41 is recovered as fine aggregate D, and the bone that has passed through the vibrating sieve 41 and has been placed on the sieve The material is collected as coarse aggregate B.

On the other hand, as the fine aggregate D is produced by the fine aggregate mill 3, fine powder by-products are produced. This by-product fine powder is fed through the fine aggregate mill 3 from the supply port 3a to the discharge port 3b.
And is collected by the flow of air sucked into the fine powder classification treatment facility 5. Further, the by-product fine powder generated in the coarse aggregate mill 2 and the aggregate classifying equipment 4 is also collected by the flow of air sucked into the fine powder classifying equipment 5. Further, the above-mentioned air flow is set to a speed at which the by-product fine powder having a particle size of 150 μm or less can be transferred.

As shown in FIG. 3, the fine-powder classifying equipment 5 is provided with a first classifier 51, a second classifier 52, and a bag filter 53. The first classifier 51 has 150 μ that has been carried by the flow of air.
Among by-product fine powders of m or less, passage of by-product fine powders of 90 μm or more is blocked, and passage of by-product fine powder of 90 μm or less is permitted. The by-product fine powder having a size of more than 90 μm and 150 μm or less captured by the first classifier 51 is stored in the tank 51a as a coarse by-product fine powder E. The coarse by-product fine powder E may be used for adjusting the particle size of the fine aggregate D, and the excess may be stored in the tank 51a.

The second classifier 52 prevents the by-product fine powder of 30 μm or less among the by-product fine powder of 90 μm or less that has passed through the first classifier 51 and the by-product fine powder of 30 μm or less from passing. It is acceptable. The by-product fine powder having a size of more than 30 μm and 90 μm or less captured by the second classifier 52 is stored in the tank 52a as a fine by-product fine powder F.

The bag filter 53 is provided with a filter for collecting the by-product fine powder of 30 μm or less which has passed through the second classifier 52. The by-product fine powder of 30 μm or less captured by the bag filter 53 is stored in the tank 53a as a fine by-product fine powder G.
In addition, FIG. 4 shows that by-product fine powder of 150 μm or less,
The result of having measured about the relationship between particle diameter and accumulation frequency is shown. From this figure, the by-product fine powder with a particle size of 30 μm or less is
It can be seen that the amount of the by-product fine powder reaches about 60% by weight, and the amount of the by-product fine powder having a particle size of 90 μm or less reaches about 80% by weight of the total by-product fine powder.

Tables 1 and 2 show the composition of the fine powder of 150 μm or less by-product obtained based on the results of chemical analysis and thermal analysis. From Table 1, in the whole by-product fine powder, the cement hydrate component and the aggregate component are 5 respectively.
It can be seen that it exists in a proportion of 0% by weight. further,
From Table 2, it is found that the by-product fine powder having a particle size of more than 30 μm and 150 μm or less contains a large amount of SiO ₂ (silicon oxide) component of 56.5% by weight, and also contains a large amount of aggregate component, and at the same time, the CaO component Since it is as small as 17.6% by weight, it can be seen that the content of cement hydrate is small. On the other hand, in the by-product fine powder of 30 μm or less, the SiO ₂ component is 4
Since it is as low as 0.4% by weight, it can be seen that the component of the aggregate is low, and since the CaO component is as high as 32.6% by weight, the component of cement hydrate is high. You can see that

[0031]

[Table 1]

[0032]

[Table 2]

The fine by-product fine powder F stored in the tank 52a and the fine by-product fine powder G stored in the tank 53a are the upper end portion of the preheater 61 in the cement manufacturing facility as shown in FIG. It is introduced as a part of the cement raw material into the cement kiln to be fired in the rotary kiln 62. On the other hand, the tank 41a
The coarse by-product fine powder E stored in is introduced into the crusher 71 for crushing the cement raw material as a part of the cement raw material, and is fired into the cement clinker in the rotary kiln 62 via the preheater 61. That is, all the by-product fine powder of 150 μm or less stored in the tanks 51a, 52a, 53a can be reused as cement.

Since the fine by-product fine powder G having a particle size of 30 μm or less has a high activity, it can be used as a solidifying material such as a ground improving material by mixing it with cement to the extent that the strength is not deteriorated. Good.

On the other hand, in the cement manufacturing facility, as shown in FIG. 1, a crusher 71 for crushing the cement raw material 80, a preheater 61 for preheating the crushed cement raw material 80,
Rotary kiln 62 for burning cement clinker,
The main component is a clinker cooler 63 for cooling the fired cement clinker.

The preheater 61 is called a suspension preheater, and includes a plurality of cyclones 61a.about.
61d is vertically connected by ducts 61h to 61k. Then, the cement raw material 80 crushed by the crusher 71 and the coarse by-product fine powder E are thrown into the uppermost duct 61h via the chute 64 as shown by the solid arrow. In addition, the fine by-product fine powder F and the fine by-product fine powder G are also introduced into the uppermost duct 61h through the chute 64. Cement raw material 80 and fine powder E, F by-products
G is cyclone 61a-61d and duct 61h-6.
It descends sequentially while passing 1k. On the other hand, the exhaust gas is sucked by the attracting fan 66 and sequentially rises in the opposite direction to the cement raw material 80 and the like as indicated by the broken line arrow, and the preheater 61.
Will be leaked from.

As a result, the cement raw material 80 that has been added is supplied.
The fine powders E, F, and G produced as by-products are gradually heated by the heat of the exhaust gas and then supplied to the cyclone 61d at the lowermost position, and then through the chute 67 and the connection housing 68 located on the kiln end side of the rotary kiln 62. Introduced into the rotary kiln 62. The high temperature air supplied from the clinker cooler 63 and the fuel 81 for burning sent from the burner 65 are introduced into the rotary kiln 62, and the cement raw material and the by-product fine powder move while rotating in the rotary kiln 62. The fired cement clinker is cooled by the clinker cooler 63 and discharged to the outside of the system.

Further, the exhaust gas discharged from the induction fan 66 is sent to the dryer 70 and the crusher 71. In the dryer 70 and the crusher 71, the preheater 61 is used.
The cement raw material 80 is efficiently dried by utilizing the heat of the exhaust gas, and then crushed. However, since the coarse by-product fine powder E is in a sufficiently dried state by the heat-rubbing treatment, it is sent to the crusher 71 without passing through the dryer 70.
The exhaust gas used by the drier 70 and the crusher 71 contains not only the dust contained when the induction fan 66 was discharged, but also the fine powder generated during the drying and crushing. The exhaust gas containing these dusts and fine powders, after dust and the like are removed by the dust collector 73, is attracted by the attracting fan 72 and is discharged to the atmosphere from the chimney 74.

Next, the function and effect of the above aggregate regenerating equipment will be described. In this aggregate regenerating facility, the concrete lumps A having a size of 5 mm or more are heat-treated in the filling type heating furnace 1, so that hot air easily flows through the gaps between the concrete lumps A. Therefore, the heating time of the concrete block A can be shortened, and the concrete block A charged into the heating furnace 1 can be uniformly heated at a constant temperature. Therefore, since the cement paste can be uniformly dehydrated and weakened, the cement paste can be efficiently and reliably separated from the coarse aggregate and the fine aggregate in the scouring process after heating.

In the coarse aggregate mill 2, since the mortar C moves from the mesh portion 22c to the outer drum 21 side, the fine aggregate in the mortar C is excessively crushed by the grinding media 23 of steel balls. There is no. That is, it is possible to prevent the fine aggregate from being crushed into smaller pieces by the grinding media 23.

On the other hand, in the fine aggregate mill 3, coarse aggregate B is used.
Since it is used as a grinding medium and a grinding medium such as steel balls is not used, it is possible to reduce the cost required for the grinding process, and the fine aggregate D has a large specific gravity such as steel balls. It is possible to prevent further fine crushing by the fir medium. Further, there is an advantage that the coarse aggregate B can be finished with the fine aggregate D, the mortar C and the like.

Further, since the by-product fine powder generated in the coarse aggregate mill 2, the fine aggregate mill 3 and the aggregate classifying equipment 4 can be recovered in the fine powder classifying equipment 5, it is possible to prevent the deterioration of the working environment. You can Then, in the fine powder classification processing facility 5, each classifier 51, 52 and the bag filter 5
By 3, the by-product fine powder can be classified into the coarse by-product fine powder E, the fine by-product fine powder F, and the fine by-product fine powder G for each of the above-described predetermined particle size ranges.

On the other hand, in the method for producing a cement clinker using the above-mentioned fine powder of by-product, the fine powder of by-product generated in the aggregate regenerating equipment is classified in the fine-powder classification processing equipment 5, and the above tank 51 is used.
a by-product fine powder E stored in a, 52a and 53a,
A method is adopted in which F and G are supplied to the preheater 61 as a part of the cement raw material, and then introduced into the rotary kiln 62 and fired.

In particular, the fine by-product fine powder F and the fine by-product fine powder G are shot 64 at the upper end of the preheater 61.
A method of introducing the coarse by-product fine powder E into the pre-heater 61 through the chute 64 after introducing the coarse by-product fine powder E into the pulverizer 71 to further finely pulverize the fine powder E is introduced.

In the method for producing the cement clinker configured as described above, the by-products fine powders E, F, and G are finally introduced into the rotary kiln 62 as a cement raw material having a predetermined particle size or less, and the cement It will be baked into a clinker. That is, by-products fine powders E, F, and G are shown in Table 1.
And as shown in Table 2, quicklime (CaO) and silicon dioxide since it contains many (SiO _2), silicates tricalcium These reactions (3CaO · SiO ₂₎ or disilicate lime (2CaO · SiO ₂₎ Can be reliably generated. Therefore, the by-product fine powder generated when the aggregate is recovered from the concrete waste material can be effectively used as a cement raw material.

Since the by-products fine powders E, F, and G contain a large amount of quick lime (CaO) and slaked lime (Ca (OH) ₂ ) as calcium sources other than calcium carbonate (CaCO ₃ ), decarboxylation It is possible to suppress the emission of carbon dioxide (CO ₂ ) due to. Moreover, since the amount of heat required for decarbonation is unnecessary, it is possible to reduce the emission amount of carbon dioxide generated when the fuel is burned. Moreover,
Since the fuel consumption can be reduced, the cost for cement production can be finally reduced. In addition, since SiO ₂ and Al ₂ O _{3 which} are usually supplied in large amounts from clay are included in the fine powder in a large amount, the amount of clay used is reduced, and as a result, the amount of heat required for dehydration of clay minerals is reduced. Therefore, this point also contributes to cost reduction. Further, fine powder is 90% or more and 20% or less, which is sufficiently fine, and does not go through the raw material crushing step.
Even if it is directly introduced into the preheater, it reacts well with other raw materials, so there is no need to perform crushing as with ordinary cement raw materials. Therefore, also from this point, it is possible to reduce the cement production cost.

Further, since the by-product fine powders E, F, and G always pass through the preheater 61, even if the by-product fine powders E, F, and G may contain water, it is possible. The by-product fine powders E, F, and G after removing the water content and heating to a predetermined temperature can be supplied to the rotary kiln 62. Therefore, the cement clinker can be efficiently manufactured.

Further, since the coarse by-product fine powder E is crushed by the crusher 71, only the crushed by-product fine powder having a size of 90 μm or less is used only for the preheater 61 and the rotary kiln 6.
2 can be supplied. Therefore, the cement clinker can be efficiently produced in the rotary kiln 62. Further, since the coarse by-product fine powder E is already finely pulverized at a stage before being put into the pulverizer, compared with the case of pulverizing a normal cement raw material,
The energy required for the crushing can be reduced. Therefore, the cement manufacturing cost can be reduced. This method is particularly effective when firing early-strength cement clinker or low-heat cement clinker, which is difficult to fire unless the raw material has a smaller particle size.

(Second Embodiment) Next, a method for manufacturing a cement clinker according to a second embodiment of the present invention will be described with reference to FIG. However, elements common to the constituent elements shown in FIG. 1 are designated by the same reference numerals, and description of the common constituent elements is omitted.

In the second embodiment, the fine by-product fine powder F and the fine by-product fine powder G are supplied to the connection housing 68 instead of the preheater 61. That is, the fine by-product fine powder F and the fine by-product fine powder G are added to the rotary kiln 62.
It is supplied to the connection housing 68 located on the kiln butt side and is fired in the rotary kiln 62.

In the method of manufacturing the cement clinker configured as described above, since the fine by-product fine powder F and the fine by-product fine powder G are guided to the kiln butt side which is the entrance side of the rotary kiln 62, the preheater 61 is provided. It is possible to reduce the pressure loss such as, for example, to reduce the electric power of the induction fan 66, and to fire the cement clinker more directly and in a shorter time. That is, the by-product fine powder is in a state where moisture and chemically bound water are removed by heating at 100 to 500 ° C., and the fine powder is 90 μm.
Since it is in the pulverized state below, the cement clinker can be efficiently fired in the rotary kiln 62 even when it is directly put into the kiln butt side of the rotary kiln 62.

Even if the coarse by-product fine powder E, the fine by-product fine powder F and the fine by-product fine powder G are concentrated and supplied to one place of the connection housing 68, the chute 64 and the crusher 71, they may be concentrated. Well, for example, the coarse by-product fine powder E is in the crusher 71, the fine by-product fine powder F is in the chute 64 to the preheater 61, the fine by-product fine powder G is in the connection housing 68, and so on. It may be dispersed in the above and supplied. Further, when the coarse by-product fine powder E is used for adjusting the particle size of the fine aggregate D and the fine by-product fine powder G is used as the solidifying material, only the fine by-product fine powder F is connected to the connection housing 68,
The chute 64 and the crusher 71 may be displaced, or may be supplied to one place or a plurality of places.

In addition, the kiln butt side of the rotary kiln 62 is
Although the position of the connection housing 68 is meant in each of the above-described embodiments, the kiln butt side may be the position of the opening end on the connection housing 68 side of the rotary kiln 61, that is, the position of the upstream end. Further, it may be the position of the kiln tail portion as an inner portion near the opening end of the rotary kiln 61. That is, the by-product fine powders E, F, and G may be supplied to the upstream opening end of the rotary kiln 62 or the kiln butt. However, as described above, by-product fine powder having a large particle size such as coarse by-product fine powder E is preferably supplied to the crusher 71.

[0054]

As described above, according to claims 1 to 3,
According to the invention described in (3), since the by-product fine powder contains a large amount of quick lime (CaO) as a calcareous raw material and silicon dioxide (SiO ₂ ) as a siliceous raw material, tricalcium silicate ( 3CaO · SiO ₂₎ or disilicate lime (2CaO · SiO ₂₎ can be reliably generated. Therefore, the by-product fine powder generated when the aggregate is recovered from the concrete waste material can be effectively used as a cement raw material.

As the calcareous raw material, quick lime (CaO) and slaked lime (Ca) other than calcium carbonate (CaCO ₃ ) are used.
Since a large amount of (OH) ₂ ) is contained, the emission of carbon dioxide (CO ₂ ) due to decarboxylation can be suppressed.
Moreover, since the amount of heat required for decarbonation is unnecessary, it is possible to suppress the emission of carbon dioxide generated when burning the fuel. Moreover, since the fuel consumption can be reduced, the cost for cement production can be finally reduced. In addition, since SiO ₂ and Al ₂ O _{3 which} are usually supplied in large amounts from clay are included in the fine powder in a large amount, the amount of clay used is reduced, and as a result, the amount of heat required for dehydration of clay minerals is reduced. Therefore, this point also contributes to cost reduction. Furthermore, the fine powder is 90% or more and 20% or less, which is sufficiently fine,
Even if the raw material is directly introduced into the preheater without going through the raw material crushing step, it reacts well with other raw materials, so that it is not necessary to carry out the crushing like the usual cement raw material. Therefore, also from this point, it is possible to reduce the cement production cost.

Further, according to the invention of claim 1, since the by-product fine powder is introduced into the preheater, even if the by-product fine powder may contain water, this The fine powder produced as a by-product after removing the above and heating to a predetermined temperature can be supplied to the rotary kiln. Therefore, the cement clinker can be efficiently manufactured.

According to the second aspect of the invention, since the by-product fine powder is guided to the kiln butt side of the rotary kiln, the pressure loss of the preheater or the like is reduced, and, for example, the power of the induction fan that sucks the exhaust gas from the preheater is reduced. In addition to the above, the cement clinker can be fired more directly and in a shorter time.

According to the invention of claim 3, 90 μm
Super fine by-product powder is crushed by a crusher and then supplied to the preheater, and by-product fine powder of 90 μm or less is introduced to the kiln butt side of the preheater or rotary kiln. Finely pulverized by-product fine powder can be supplied. Therefore, the cement clinker can be efficiently produced in the rotary kiln. In addition, since fine powder of by-product having a size of more than 90 μm is already finely pulverized before being put into the pulverizer, the energy required for the pulverization is reduced as compared with the case of pulverizing a normal cement raw material. Can be achieved. Therefore, the cement manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a cement manufacturing facility directly used for carrying out a method for manufacturing a cement clinker according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing an aggregate regenerating facility that produces by-product fine powder used in the method for producing the cement clinker.

FIG. 3 is a schematic configuration diagram showing a fine powder classification treatment facility in the aggregate regenerating facility.

FIG. 4 is a diagram showing the results of measuring the relationship between the particle size of by-product fine powder produced in the aggregate regenerating facility and the cumulative frequency.

FIG. 5 is a schematic configuration diagram showing a cement manufacturing facility used directly for carrying out a method for manufacturing a cement clinker according to a second embodiment of the present invention.

[Explanation of symbols]

61 Preheater 62 rotary kiln 68 Connection housing (part on the kiln side) 80 Cement raw material A concrete block B Coarse aggregate (aggregate) D Fine aggregate (aggregate) E Coarse by-product fine powder (By-product fine powder) F Fine by-product fine powder (By-product fine powder) G Fine by-product fine powder (By-product fine powder)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hirokazu Shima             1-3-25 Koishikawa, Bunkyo-ku, Tokyo Koishikawa Univ.             Kuni Building Mitsubishi Materials Corporation Environmental Lisa             Uccle Business Center (72) Inventor Takeyuki Nakato             1-3-25 Koishikawa, Bunkyo-ku, Tokyo Koishikawa Univ.             Kuni Building Mitsubishi Materials Corporation Environmental Lisa             Uccle Business Center (72) Inventor Go Misaka             1-3-25 Koishikawa, Bunkyo-ku, Tokyo Koishikawa Univ.             Kuni Building Mitsubishi Materials Corporation Environmental Lisa             Uccle Business Center

Claims (3)

[Claims] 1. A preheater for preheating a cement raw material by utilizing exhaust gas from a rotary kiln, which is a by-product fine powder generated when collecting aggregate from a concrete mass after heat treatment at 100 to 500 ° C. The method for producing a cement clinker, wherein the method is introduced into the above rotary kiln and fired. 2. Fine powder produced as a by-product when collecting aggregate from a concrete block after heat treatment at 100 to 500 ° C. is introduced as a part of the cement raw material into the kiln butt side of a rotary kiln for firing the cement raw material. A method for producing a cement clinker, which comprises firing in the above rotary kiln. 3. By-product fine powder produced when collecting aggregate from a concrete block after heat treatment at 100 to 500 ° C. is classified, and the by-product fine powder having a particle size of 90 μm or less is obtained from the preheater or the rotary kiln kiln. The by-product fine powder having a particle size of more than 90 μm introduced into the tail side is introduced as a part of the cement raw material into a crusher for crushing the cement raw material, and is fired in the rotary kiln through the preheater. Item 3. A method for producing a cement clinker according to Item 1 or 2.