JP2001018000A - Treatment of sludge and treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable pulverization and to expand the recycling of sludge by including a stage for dehydrating the sludge to a specific moisture content or below by a dehydration treatment, then to a specific moisture content or below by hot air drying and further, pulverizing the sludge to a specific grain size or below, a stage for pulverizing the sludge until a B laine ratio surface area attains a specific value or above, and a capturing stage. SOLUTION: The sludge slurry generated in a ready mixed concrete production plant, or the like, is stored in a settling device 1 and is subjected to sedimentation separation. The separated sludge is subjected to the dehydration treatment in a dehydrating device 2 to a moisture content of <=60%. The dehydrated sludge is dried in a drying and pulverizing device 3 and is pulverized, by which the dry sludge of about 15% moisture content to be below <=20% moisture content and about <=10 mm grain size to be below <=15 mm grain size is obtained. Next, this dry sludge is fed into a wind pulverizing device 4 and is pulverized. The sludge of large grain sizes is repulverized by sieving and sorting and is captured in a capturing device 5, by which the particulate sludge of <=10 μm in average grain size and >=7000 cm2/g in B laine ratio surface area is obtained. This sludge is usable for a ready mixed concrete admixture, soil conditioner, and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for treating sludge generated in a ready-mixed concrete production plant or the like.

[0002]

2. Description of the Related Art Sludge generated in ready-mixed concrete factories and the like is classified as sludge in the "Law on the Treatment and Cleaning of Wastes". I have. However, it is difficult to stably secure such a managed disposal site in the future from the viewpoint of cost and location conditions, and various methods for effectively utilizing sludge without discarding it have been proposed. However, the technology of drying and pulverizing sludge has attracted attention as a practical technology because of the wide range of use of the obtained granular sludge.

For example, Japanese Unexamined Patent Publication No. Hei 7-315971 discloses that a raw decontaminated cake having a solid content of 20 to 70% by weight is dehydrated by a dehydrator such as a filter press or dried by solar drying or the like. Add water, waste water from a concrete plant, etc., mix and stir evenly with a mixer, dry granulate with a spray drier, and granulate or spherical with an average particle size of 50-100 μm. A method is disclosed in which sludge granules having excellent handling properties without waste are reused as silicate lime fertilizer.

[0004] Japanese Patent Application Laid-Open No. 9-217343 discloses that sludge separated from aggregate of remaining ready-mixed concrete contains three sludges.
After elapse of a predetermined curing time, the active dehydrated cake obtained by dehydration within 4 hours is granulated by a granulator to form a granular cake, which is cured for a predetermined number of days in a storage area of a canopy to obtain a water content of 22%. Through a drying and pulverizing process to obtain a powder having a water content of 5 to 6% or less and a particle size of 0.15 mm or less. Recycling methods, such as mixing in mud, are disclosed.

Further, the present inventors have developed a technology for producing a dried sludge by pulverizing a dewatered cake having a water content of 30% or less by a drying treatment at the time of generation of raw con sludge by a wind pulverizer using a swirling air flow. Developed (Symposium on Effective Use of Concrete Sludge Proceedings 199
6.5). The powder and granules crushed by this wind crusher are J
IS R5201 Fine particles having a specific surface area of about 6800 cm ² / g according to the physical test method of cement can be used as a ready-mixed concrete admixture, a void filler, a lightweight embankment material, a soil improvement material, and the like.

[0006]

As described above, by drying and granulating the raw concrete sludge, the reuse range of the raw concrete sludge is being expanded. However, in the conventional method of drying raw granulated sludge and granulation, the efficiency of dewatering or drying sludge is low, and
There is a limit to the particle size of the resulting granules.

In the method described in Japanese Patent Application Laid-Open No. Hei 7-315971, since the sludge is dewatered by a dehydrator or solar drying, it can be dehydrated only up to a water content of about 50%. Since the granules having the above-mentioned ratio are dried and granulated by a spray dryer, the granulated granules having an average particle size of only about 50 to 100 μm can be obtained.

According to the method described in Japanese Patent Application Laid-Open No. 9-217343, it takes time to cure the dehydrated cake and the granular cake, and the resulting powdered granules have a particle size of about 150 μm or less.

[0009] In the method described in the above-mentioned collection of reports, the drying of sludge is simply performed by blowing hot air, so that the dewatered cake at the stage of being introduced into a wind pulverizer has a particle size of about 30 to 50 mm. It is relatively large, and the powder obtained by the wind mill has an average particle size of 10 to 20.
Only about μm can be obtained.

The problem to be solved in the present invention is to improve the sludge drying efficiency in the drying and granulation of sludge and to establish a sludge treatment technology capable of forming fine particles of pulverized powder and granules. The goal is to further expand reuse.

[0011]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have taken measures to reduce the particle size of the pulverized particles in the step of dewatering, drying and pulverizing the sludge after settling. As a result of repeated experiments, it was confirmed that by crushing the dried sludge at the stage before being put into the wind pulverizer, it could be pulverized into finer particles by the wind pulverizer, and the present invention was completed. .

That is, the present invention relates to a method for treating sludge obtained by precipitating and separating sludge slurry generated in a ready-mixed concrete production plant or the like and then drying and pulverizing the sludge into powdery granular sludge. A drying and pulverizing step of drying the sludge having a water content of 60% or less by hot water drying to a water content of 20% or less and pulverizing the sludge to a particle size of 15 mm or less during drying, and a dry sludge after the drying and pulverizing step Pulverizing to a particle size having a Blaine specific surface area of 7000 cm ² / g or more by wind pulverization using a swirling air flow, and a collecting step of collecting the granular sludge after the fine pulverizing step. Features.

The sludge after the precipitation and separation is dewatered to a water content of 60% or less, preferably 30% or less, and then dried with hot air to a water content of 20% or less, preferably 15% or less, more preferably 10% or less. By drying and pulverizing in the course of drying to obtain a dried sludge having a particle size of 15 mm or less, preferably 10 mm or less, throwing the dried sludge into a wind pulverizer to pulverize, screening a large particle size sludge, sifting and re-pulverizing. And finally the average particle size is 10 μm
Fine particles of a degree or less are obtained.

The pulverized sludge having fine particles having an average particle size of about 10 μm or less has a Blaine specific surface area of 7000 to 12
000 cm ² / g, and by using such fine particles, a conventional Blaine specific surface area of 6800 c
Its use range is expanded as compared with pulverized sludge of about m ² / g.

Drying and pulverization of the sludge in the drying and pulverizing step can be performed by a mesh conveyor provided in a plurality of stages and a pulverizer provided in the middle of the mesh conveyor in each stage. Specifically, for example, a mesh conveyor having a mesh of 5 mm is installed in a plurality of stages, and dried by blowing hot air of about 400 ° C., and the sludge remaining without falling from the mesh of the mesh conveyor of each stage is crushed by a crusher. By doing so, pulverized sludge having a particle size of 15 mm or less can be obtained.

Here, the mesh conveyor may have a structure in which a mesh in which a plurality of flat spirally extending wires are connected in a row is attached to a chain. With this configuration, a mesh is formed three-dimensionally, clogging by sludge is reduced, and spiral wires in each row oscillate with each other to crush massive sludge and promote drying. There is a utility to make it.

The fine pulverization of the sludge in the fine pulverization step is performed by a wind power pulverizer. The wind pulverizer itself is known, and specific structures and functions are described in, for example, JP-A-7-136542 and JP-A-7-185310. Such a wind pulverizer or a wind pulverizer described in the above-mentioned publication of the present inventors can be used. For example, a wind pressure 77
By blowing air at 0 mmAg and a flow rate of 120 m ³ / min, the particles can be efficiently pulverized into fine particles having an average particle size of about 10 μm or less.

The collecting step includes a classifier equipped with a sieving device,
It can be performed using a collector and a dust collector provided with a fine screen. Classifiers, collectors, and dust collectors are known in the art. These devices are combined to collect fine particles discharged from a wind pulverizer.

[0019]

FIG. 1 is a system diagram showing a sludge treatment system according to an embodiment of the present invention. This system is a system that obtains dry fine powder sludge by treating sludge slurry generated in a ready-mixed concrete manufacturing plant or the like.

In FIG. 1, reference numeral 1 denotes a sedimentation device for storing sludge slurry generated in a ready-mixed concrete manufacturing plant and the like for sedimentation and separation, 2 a dehydration device for dewatering the separated sludge and 3 for drying dewatered sludge with hot air. A drying and pulverizing device for pulverizing, 4 is a wind power pulverizing device for finely pulverizing dried sludge by wind power, and 5 is a collecting device for collecting pulverized sludge. The structures and functions of the precipitating device 1 and the dehydrating device 2 are known, and thus detailed description is omitted.

FIG. 2 is a schematic front view showing the structure of the drying and crushing apparatus 3, FIG. 3 is a view showing the structure of a mesh conveyor, FIG. 2 (a) is a partial plan view, and FIG. FIG. The drying and crushing apparatus 3 of the present embodiment includes a mesh conveyor 31 installed in three stages, a crusher 32 installed in the middle of the mesh conveyor 31 in each stage, a hot air blowing nozzle 33 and an input hopper 34 provided above the mesh conveyor 31. Is the main configuration.

The sludge separated from the sludge slurry generated in the ready-mixed concrete manufacturing plant or the like is subjected to a dewatering treatment to dewater the sludge to a water content of 60% or less. The dewatered sludge is charged from the charging hopper 34 and is moved on the mesh conveyor 31. Then, while being heated and dried by the hot air from the hot air blowing nozzle 33, the crusher 32 installed in the middle of the conveyor
And is discharged outside by a discharge device (not shown).

The mesh conveyor 31 is, as shown in FIG.
A net 31c is attached to a shaft 31b provided on a chain 31a. The reticulated body 31c has many rows of wires extending in a flat spiral shape (only three rows are shown in the figure).
Are entangled and connected. With such a net 31c, a mesh is formed three-dimensionally, and clogging by sludge is reduced, and
The spiral wires in each row can oscillate with each other to break up bulk sludge and promote drying. The mesh interval is about 5 mm, and among the sludge placed on the mesh body 31c, the sludge smaller than the mesh interval falls through the mesh during movement. Sludge that has fallen from the net 31c is scraped by the scraper 3 attached to the lower surface of the net 31c.
It is scraped by 1d and sent to the discharge device from the screw conveyor 31e.

The hot-air blowing nozzles 33 have a nozzle width corresponding to the entire width of the mesh conveyor 31, and are provided at appropriate intervals above the mesh conveyor 31 in each stage. Hot air is supplied from a separately installed hot air generator, and hot air of about 400 ° C. is blown toward the sludge. The sludge is dried by the hot air, and the sludge remaining without falling from the meshes of the upper and middle reticulated conveyors 31 is pulverized by the pulverizer 32 to be dried sludge having a particle size of 15 mm or less.

FIGS. 4A and 4B are diagrams showing the configuration of the wind pulverizer 4, wherein FIG. 4A is a front view and FIG. 4B is a right side view. The wind crusher 4 of the present embodiment has an exhaust port 42 connected to the downstream collecting device 5 at the upper end and a damper 43 for adjusting the opening amount.
, An intermediate cylindrical casing 45 into which a reduced diameter portion 44 below the upper cylindrical casing 41 is inserted as an inner tube, and an intermediate cylindrical casing 4
A blower 46 for blowing air into the blower 5, a blower pipe 47, a lower conical casing 48 having a discharge port 49 at a lower end, and a hopper 5 for supplying dry sludge to the lower conical casing 48.
0 is provided.

The air blown into the intermediate cylindrical casing 45 from the blower pipe 47 by adjusting the opening amount of the exhaust port 42 by the damper 43 is mainly transmitted between the intermediate cylindrical casing 45 and the reduced diameter portion 44 of the upper cylindrical casing 41. It descends as a swirling vortex. The dried sludge introduced from the hopper 50 is taken into the main swirling vortex and is treated for a certain period of time.
8, descends along the inner peripheral surface, and is discharged from the discharge port 49.
Those having a small particle size and density rise in the center and exhaust ports 42
And is sent to the collecting device 5 on the downstream side.

The lower conical casing 48 of the wind mill 4
The pulverized material discharged from the discharge port 49 is subjected to a sieve sorter (not shown) to sort out and remove foreign matters such as iron pieces, crushed stone, fine sand, and the like, and the pulverized sludge having a large particle diameter is re-input to the wind pulverizer 4. .

FIG. 5 is a view showing the structure of the trapping device 5. The collection device 5 according to the present embodiment includes a classifier 51 (for example, a dry cyclone classifier manufactured by Environmental Development Co., Ltd.) having a sieving device (not shown) therein, and a bilayer having a fine screen. Type collector (for example, Pyro Screen (trade name) manufactured by Environmental Development Co., Ltd.) 52, dust collector (for example, Bag Filter Dust Collector manufactured by Environmental Development Co., Ltd.) 53
Can be carried out by a collecting device comprising: The classifier 51, the collector 52, and the dust collector 53 are known, and a detailed description thereof will be omitted.

The sludge treatment system of the present embodiment is operated under the above-mentioned equipment configuration. The treatment procedure is as follows. First, a sludge slurry generated in a ready-mixed concrete manufacturing plant or the like is stored in a sedimentation device 1 and separated by sedimentation, and the separated sludge is subjected to dehydration treatment in a dehydration device 2 to a water content of 60%, preferably 30% or less. The dewatered sludge is dried and pulverized by the drying and pulverizing device 3 to obtain a dried sludge having a water content of 15% and a particle size of 10 mm or less.

Next, the dried sludge is put into a wind pulverizer 4 to be pulverized, and the sludge having a large particle size is sieved, re-pulverized, collected by a collector 5 and collected with an average particle size of 10 μm.
m or less, and a fine particle sludge having a Blaine specific surface area of 7000 cm ² / g or more is obtained. The obtained fine particle sludge can be used as a ready-mixed concrete admixture, a void filling material, a lightweight embankment material, a soil improvement material, and the like.

[0031]

According to the present invention, the following effects can be obtained.

(1) Before the dry sludge is pulverized in the wind pulverization step, the dewatered sludge is dried to a water content of 20% or less in the dry pulverization step and pulverized to a particle size of 15 mm or less during the drying. The dried sludge can be pulverized to a particle size such that the specific surface area of the brane is 7000 cm ² / g or more. By such pulverization,
The sludge recycling can be expanded.

(2) Drying and crushing of dewatered sludge efficiently by drying sludge in the drying and crushing process on a plurality of mesh conveyors and crushing the sludge in the middle of each mesh mesh conveyor. Can be.

(3) A mesh is formed three-dimensionally by using a mesh conveyor having a structure in which meshes in which a plurality of flat spirally extending wires are connected in a large number of rows are attached to a chain, thereby preventing clogging with sludge. At the same time, the spiral wires in each row can oscillate with each other to break up massive sludge and promote drying.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a sludge treatment system according to an embodiment of the present invention.

FIG. 2 is a schematic front view showing an apparatus configuration of the drying and crushing apparatus of FIG.

3A and 3B are diagrams showing a structure of a mesh conveyor of the drying and crushing apparatus of FIG. 2, wherein FIG. 3A is a partial plan view, and FIG.
It is an arrow A view.

FIG. 4 is a diagram showing an apparatus configuration of the wind pulverizer of FIG. 1;

FIG. 5 is a diagram showing a device configuration of the collecting device of FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 sedimentation device 2 dehydration device 3 drying and crushing device 31 mesh conveyor 31a chain 31b shaft 31c mesh body 31d scraper 31e screw conveyor 32 crusher 33 hot air blowing nozzle 34 input hopper 4 wind crusher 41 upper cylindrical casing 42 exhaust port 43 damper 44 compression Diameter part 45 Intermediate cylindrical casing 46 Blower 47 Blower tube 48 Lower conical casing 49 Discharge port 50 Hopper 5 Collector 51 Classifier 52 Collector 53 Dust collector

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Chihiro Suemoto 1391-1, Otani, Shizuoka City, Shizuoka Prefecture Environmental Technology Development Co., Ltd. (72) Inventor Yoshiaki Sato 2-3-5 Nishikicho, Oita City, Oita Prefecture F-term (Reference) 4D059 AA30 BD01 BD26 BD32 BD40 BE00 BE31 BF15 BK11 BK30 CB04 CB18 CC04 EB01 EB07 EB20

Claims (5)

[Claims] 1. A method of treating sludge after precipitating and separating sludge slurry generated in a ready-mixed concrete production plant or the like, and drying and pulverizing the sludge into powdery granular sludge. A drying and pulverizing step of drying the dewatered sludge having a water content of 60% or less by hot air drying to a water content of 20% or less and pulverizing the dried sludge to a particle size of 15 mm or less during the drying, A method of treating sludge, comprising: a fine pulverizing step of pulverizing particles to a particle size having a brane specific surface area of 7000 cm ² / g or more by wind pulverization using a powder, and a collecting step of collecting the granular sludge after the fine pulverizing step. 2. The sludge treatment method according to claim 1, wherein the drying of the sludge in the drying and crushing step is performed on a plurality of mesh conveyors, and the crushing of the sludge is performed in the middle of each mesh conveyor. . 3. A sludge processing apparatus for drying and pulverizing sludge after precipitating sludge slurry generated in a ready-mixed concrete production plant or the like to obtain powdery granular sludge, comprising: A drying and crushing device for drying and crushing by hot air, a wind crushing device for finely crushing the dried sludge dried and crushed by the drying and crushing device, and a collecting device for collecting powdery granular sludge finely crushed by the wind crushing device. Sludge treatment equipment provided. 4. The drying and crushing apparatus according to claim 3, wherein a mesh conveyor for placing and conveying the sludge is installed in a plurality of stages, and a crusher is installed in the middle of the mesh conveyor in each stage. Sludge treatment equipment. 5. The sludge processing apparatus according to claim 4, wherein the mesh conveyor has a structure in which a mesh in which a plurality of flat spirally extending wires are connected in a plurality of rows is attached to a chain.