JP2646938B2 - Method of producing flue gas desulfurization material from construction waste - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recycling construction waste material, and more particularly to a method for producing a flue gas desulfurization material from fine powder mortar obtained by crushing concrete from construction waste material.

[0002]

2. Description of the Related Art Conventionally, concrete (mass) occupying a large part of construction waste is crushed to a size of about 50 mm and reused as roadbed material or backfill material. However, such a method of use is limited in its use, so it is not possible to secure a sufficient amount of use, and waste materials that could not be used must be disposed of as waste. The problem arises from the viewpoint of.
Also, concrete aggregate contains aggregates such as gravel and crushed stone and unreacted cement.However, the conventional method of recycling construction waste is to think about the resources contained in concrete. Instead, it was merely considered to be used as roadbed material or backfill material, and no consideration was given to using these resources effectively.

[0003] In view of such circumstances, the present applicant has filed a patent entitled "Method for producing carbon dioxide consuming material from carbon dioxide consuming material and construction waste material" on February 7, 1992 (Japanese Patent Application No. Hei. -56051 , Tokuho 7-83831
And proposed to obtain carbon dioxide consuming material from construction waste. According to this application, a material that consumes carbon dioxide, which causes global warming, by using construction waste can be obtained. On the other hand, in order to protect the global environment, it is necessary to remove sulfur oxides (SO ₂ , SO ₃ ) in flue gas generated from combustion of petroleum products, coal and the like. Conventionally, typical flue gas desulfurization materials include limestone (CaCO ₃ ) and slaked lime (C
a (OH) ₂ ) has been used. The desulfurization reaction by limestone is CaCO ₃ + SO ₂ + 2H ₂ O → CaSO ₃ .2H ₂ O + CO ₂ , and carbon dioxide (CO ₂ ) is generated. That is, when processing 1 mol of sulfur dioxide (SO ₂ ),
There was a problem that 1 mol of carbon dioxide was generated.

Next, the desulfurization reaction by slaked lime is as follows: Ca (OH) ₂ + SO ₂ + H ₂ O → CaSO ₃ .2H ₂ O This reaction itself does not generate carbon dioxide,
In the process of producing slaked lime, limestone (CaCO ₃ ) is
It is decomposed into carbon dioxide and quicklime (CaO: calcium oxide) by heating at 00 ° C. or higher, and is reacted with water to produce slaked lime. That is, carbon dioxide is generated in the process of producing slaked lime. Therefore, even in this desulfurization reaction, 1
When treating mol sulfur dioxide, 1 mol of carbon dioxide was generated. Furthermore, as a prior application technique, Japanese Patent Application No. 58-78219 (Microfilm of Japanese Utility Model Application Laid-Open No. 59-184930) discloses a method of pulverizing concrete waste to obtain concrete particles. A method for producing an acidic absorbent is disclosed. However, in this technique, although there is a description of crushing or sizing concrete waste material as a means for realizing the manufacturing method, no specific means is disclosed, and development of the specific means is desired. Was rare.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and as a technique that is more embodied than the prior application technique, is to reclaim gravel, crushed stone, and other resources from concrete waste of construction waste. Technology that solves the problem of waste disposal of construction waste material, and effectively uses the resources contained in construction waste material as flue gas desulfurization material to avoid new generation of carbon dioxide and recover sulfur oxides Used for
It is an object of the present invention to provide a method for producing a flue gas desulfurization material .

[0006]

SUMMARY OF THE INVENTION The present invention has been made by paying attention to a phenomenon in which concrete is neutralized by carbon dioxide in the air. The present invention crushes concrete flakes generated as construction waste to remove gravel or crushed stone. The present invention provides a method for producing a flue gas desulfurizing material from a fine powder mortar generated when obtaining coarse aggregate such as the above.

Concrete is calcium hydroxide (Ca)
(OH) ₂ ) and calcium carbonate (CaCO ₃ ).

According to the present invention, a fine powder mortar obtained by crushing and regenerating concrete waste of construction waste material is used as a flue gas desulfurizing material. Sieving.
Whereas with bone material is about 1 ton / cm ² or more compression strength of the concrete which occur as construction waste, cement paste (mortar) included in concrete blocks have a 500 kg / cm ² or less of compressive strength at maximum It's just The present invention provides a method of separating a cement paste component and an aggregate such as gravel or crushed stone by using a difference in compressive strength between the materials constituting the concrete chaff to obtain a fine powder mortar component. It is possible to remove mortar adhering around gravel and crushed stones by threshing rice and dividing it into brown rice and rice husks, or by adopting a method similar to the method of milling brown rice and dividing it into white rice and bran. It separates to obtain a fine powder of mortar.

[0009] In the separation method used in the method of the present invention, a concrete crush is crushed by a primary crusher to a particle size of about 50 mm, and then the concrete flakes are charged into a secondary crusher and pressure is increased in a high density state. By crushing for a long time while adding, the mortar adhering to the aggregate is separated from the aggregate to form a fine powder. Fixed crusher used for secondary crushing and rotating upper liner
The lower liner is 120 to 1
When it is urged upward with a strength of about 30 kg / cm ²
In both cases, we will set up a weir near the outlet of the lower liner.
Therefore, the outlet angle is set sufficiently smaller than the repose angle of the raw material.
A crusher that feeds raw material particles between a fixed upper liner and a rotating lower liner to produce crushed sand sized by rotation of the lower liner, for example, a gyra disk crusher (trade name: Ube Industries, Ltd.) Can be used.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for producing a flue gas desulfurization material of the present invention will be described with reference to the drawings. The raw material used in the method for producing a flue gas desulfurization material of the present invention is concrete generated at a construction site.

The concrete waste 1 generated as a waste material at a construction site or the like is put into a hopper 2 and then conveyed to an upper part of a primary crusher by a belt conveyor 3 and put into a hopper 4 of the primary crusher. The primary crusher 5 includes a fixed piece 5
For example, a compression crusher called a jaw crusher, which includes a movable piece 52 connected to the rotating body 53 by a link mechanism 54 and reciprocating toward the fixed piece 51, can be used. 1 which passed the primary crusher
The next crushed concrete flake 11 is crushed to a particle diameter of 50 mm or less. Next, the primary crushed concrete flakes 11 are conveyed to the upper part by the belt conveyor 6 and are introduced into the secondary crusher 7 to be subjected to secondary crushing for separating aggregate and mortar.

The amount of the raw material in the crusher 7 is monitored using a level meter or the like, and the amount of the raw material input to the crusher and the amount of the product discharged from the crusher are equalized, so that a certain amount of the raw material By performing the choke feed operation that stays inside, stable secondary crushing can be performed. The secondary crusher 7 includes a fixed upper liner 71 and a lower liner 72 rotated by a rotation shaft 74, and a space formed between the upper liner 71 and the lower liner 72 becomes narrower toward the discharge port 73. For example, a gyra disk crusher (trade name: Ube Industries, Ltd.) that produces crushed sand sized by rotation of a lower liner can be used.
The width of the discharge port 73 can be set to an arbitrary size.
It is desirable to set it to 30 mm. By adjusting the width of the discharge port 73, the residence time in the secondary crusher can be adjusted. The rotating shaft of a conventional cone crusher is urged upward with a strength of about 30 kg / cm ² , whereas the rotating shaft of this crusher has 120 to 1
It is urged upward with a large strength of about 30 kg / cm ² . As the applied pressure increases, the degree of separation of the adhered mortar component increases. further,
The secondary crusher 7 is located near the outlet 73 of the lower liner 72.
By providing a weir, the angle of the outlet is the repose angle of the raw material
It is set small enough.

The primary crushed concrete flakes 11 put into the secondary crusher 7 have friction between particles in the space of the secondary crusher, and the mortar having a small compressive strength attached to the aggregate has a friction between particles. Thus, the aggregate and the mortar are separated from the aggregate, and are discharged from the discharge port 73 as the recycled material 12. In order for the secondary crusher to sufficiently separate the concrete, it is necessary that the concrete particles stay in the crusher for a long time. When the raw material is put into a normal cone crusher, the raw material passes quickly,
In the secondary crusher 7 provided with a weir near the discharge port 73 of the lower liner 72, the passage time is about 4 to 10 seconds, and the residence time of the raw material can be extended. That is, by providing a weir near the discharge port 73, the angle of the discharge port becomes the repose angle of the raw material (the stacking angle at which the particles can be stably stacked. If the stacking angle is larger than this angle, the particles will fall off). Since the size is set to be sufficiently small, the raw material does not easily pass through the crusher and fall, so that the residence time can be increased.

Further, by providing a plurality of crushers as the secondary crusher 7 and using these crushers in multiple stages,
Aggregate and mortar can be more completely separated.
In this case, by changing the operating conditions of each crusher according to the size of the particles to be charged and making the crushing machine proper, it is possible to prevent the aggregate itself from being crushed to a desired size or less, and to prevent the mortar from being crushed. The components can be more completely separated, and a high-quality recycled material can be obtained. A part of the reprocessed material 12 can be returned to the secondary crusher 7 as an abrasive 17. By adding the abrasive, the mortar attached to the aggregate can be more sufficiently separated.
When crushed stones or jams having a particle size of 2.5 to 5 mm are used as the abrasive, the mortar attached can be efficiently removed without crushing the aggregate.

The mixture of the separated reprocessed materials 12 discharged from the secondary crusher 7 is sieved by a sieve 8, and is a medium-sized aggregate 13 made of gravel having a particle size of 15 to 20 mm and a particle size of 5 The fine aggregate 14 having a grain size of 5 mm or less and the fine aggregate having a particle size of 5 mm or less are further divided by an air separator 9 into 0.13 to 5 mm. Fine aggregate 15 made of sand or the like and a particle size of 0.1
It is separated into fine particles 16 such as mortar of 3 mm or less.

As a result of a composition analysis, it was found that concrete contains about 8% of CaCO ₃ and about 16% of Ca (OH) ₂ in total. The present invention is directed to CaCO ₃ and Ca (OH) contained in concrete recovered from construction waste as described above.
₂ is regenerated as flue gas desulfurization material. Since an existing concrete material is used as a material, a material that recovers sulfur oxides in the flue gas of petroleum products and coal can be obtained without newly generating carbon dioxide.

[0017]

According to the present invention, the following effects can be obtained by the above configuration. 1. According to the first aspect of the present invention, the concrete of the construction waste material is composed of a limestone (CaCO ₃ ) component and a slaked lime (Ca
Focusing on the inclusion of (OH) ₂ ) components, mortar particles containing these components are collected to produce flue gas desulfurization materials, which do not generate any additional carbon dioxide, thus helping to reduce global warming. It is possible to collect sulfur oxides in flue gas, which is also a cause of acid rain, while preventing the generation of carbon dioxide, which is a cause of air pollution, and has an effect that greatly contributes to global environmental protection as a whole. Further , the rotating shaft of the crusher in the second step is 12
Since it is urged upward with a strength of about 0 to 130 kg / cm ^{2, the} degree of separation of the adhered mortar component can be increased. In other words, the primary crushed concrete put into the crusher of the second step, the particles rub against each other in the space of the crushed stone crusher of the second step, and the mortar having a small compressive strength attached to the aggregate is mixed with the particles. The friction is removed from the aggregate, the aggregate and the mortar are separated, and can be discharged as a recycled material from the discharge port. In addition, the second
The process crusher is equipped with a weir near the lower liner outlet.
The angle of the outlet is sufficiently smaller than the angle of repose of the raw material
Raw material slips through the crusher and falls
And the residence time can be increased,
Recovers mortar content as fine particles without fail, and
Used as a flue gas desulfurization material to recover sulfur oxides from charcoal flue gas
be able to. 2. According to the second aspect of the invention, in addition to the above effects, the secondary crusher 7 is configured so that the width of the discharge port 73 can be adjusted.
By adjusting the width of the outlet 73,
And the residence time in the secondary crusher 7 can be adjusted.
At the same time, make the diameter of the
Can be. 3. According to the invention described in claim 3, the above-mentioned claim 1 or
In addition to the effect of the second aspect of the present invention, the use of the abrasive enables efficient removal of the attached mortar without breaking the aggregate.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a process for producing a carbon dioxide consuming material of the present invention from construction waste.

[Explanation of symbols]

1 concrete, 5 primary crusher, 7 secondary crusher, 8 sieve, 9 air separator, 1
1 primary crushed concrete, 12 reprocessed materials,
13 medium aggregate, 14 small aggregate, 15 fine aggregate,
16 fine particles, 17 abrasive, 71 upper
Ina, 72 Lower liner, 73 outlet.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-69145 (JP, A) JP-A-3-296445 (JP, A) JP-A-63-65959 (JP, A) 184930 (JP, U) Actually open 62-17336 (JP, U)

Claims (3)

(57) [Claims] 1. A method for producing a flue gas desulfurization material from fine powder mortar obtained by crushing concrete waste as construction waste material, comprising: a first crushing step of crushing concrete waste by compression; Secondary crushing of the primary crushed concrete flakes obtained in the crushing step by rubbing under high density and high pressure
And a step of sieving the reprocessed aggregate mixture obtained in the second crushing step to obtain a fine cement raw material. The crusher used in the second crushing step comprises a fixed upper liner and A rotating lower liner, the lower liner being urged upward with a strength of about 120 to 130 kg / cm ² , and a weir near a discharge port of the lower liner.
The angle of the outlet is greater than the angle of repose of the raw material
Ken, which is a sufficiently small set the crusher
Method of producing a flue gas desulfurization material from setting waste. 2. A crusher used in the second crushing step.
The method for producing a flue gas desulfurization material from construction waste material according to claim 1, wherein the width of the discharge port is configured to be adjustable . 3. The method for producing a flue gas desulfurization material from construction waste material according to claim 1, wherein an abrasive is introduced into the crusher in the second crushing step. .