JPH02162003A - Method and apparatus for regenerating washing residue of ready-mixed concrete - Google Patents

Abstract

PURPOSE:To enhance the content of cement unhydrate in fine sludgy particles and effectively utilize washing residue by a method wherein sludge water is taken out and separated into highly concentrated sludge water and separated liquid and, after that, the separated liquid is stored so as to produce supernatant water in order to prepare sludge water having the predetermined concentration, resulting in obtaining slurry of fine sludgy particles mainly consisting of cement unhydrate. CONSTITUTION:Sludge water H, which is taken out with a classifier 10, is continuously separated centrifugally with a concentrator 20 into highly concentrated sludge water KH mainly consisting of cement unhydrate and separated liquid B. The highly concentrated sludged water KH is directly fed to a concentration controlling tank 30. The separated liquid B contains the hydrated component and unhydrated component of cement in the form of suspended substance and stored in a separated liquid storage tank 37. After the highly concentrated sludged water KH is prepared to the predetermined concentration by feeding the supernatant water L of the separated liquid to the concentration controlling tank 30, the sludge water KH is vibratingly pulverized with a vibration ball mill 40 so as to obtain fine sludgy particles with high content of cement unhydrate. As a result, the quality of concrete with fine sludgy particles is enhanced and the amount of cement to be used can be reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for recycling the washing residue of ready-mixed concrete generated when a transport vehicle, a plant mixer, etc. are washed with ready-mixed concrete, and an improvement of the apparatus. be.

[Prior Art] The present applicant has extracted unhydrated cement from the washing residue of ready-mixed concrete, which conventionally had little use and had no choice but to throw it away, without drying it, and mixed it with new cement. We proposed a method and device for recycling the washing residue of ready-mixed concrete that can produce high-quality concrete by combining them (Japanese Patent Application Laid-Open No. 62-204867
).

In this regeneration method, the washed concrete residue is first wet-classified using a classifier, gravel and sand are removed, and sludge water is extracted. Next, the sludge water is sedimented by the action of gravity using Shirafuna to concentrate the sludge water, and then the concentration of the concentrated sludge water is further increased to a predetermined concentration using a concentration adjustment tank. Finally, the sludge water of a predetermined concentration is vibrated and pulverized using a vibrating ball mill to obtain a slurry of fine sludge particles in which unhydrated cement appears on the surface.

[Problems to be Solved by the Invention] However, in the conventional regeneration method described above, the low hydration components of cement in the sludge water and the components that are considered not to be hydrated are allowed to settle by gravity, and this concentrated sludge water is shaken. Since vibration pulverization is performed using a ball mill, there is a problem in that it is difficult to increase the content of useful unhydrated cement in the sludge particles.

Furthermore, since Shirafuna is used as a concentrator, the concentration work is a batch process and takes a relatively long time, and it is not possible to separate the concentrated sludge water from Shirafuna's supernatant water and take out only the concentrated sludge water. As a result, the concentration of the concentrated sludge water decreases, causing the problem that the sludge water must be concentrated in a concentration adjustment tank before vibration pulverization.

An object of the present invention is to provide a ready-mixed concrete that has a short concentration time for sludge water, is easy to adjust the concentration, and can further improve the content of unhydrated cement in sludge particles to effectively utilize washing residue. An object of the present invention is to provide a method for regenerating washing residue and an apparatus for the same.

[Means for Solving the Problems] The present inventors have focused on the fact that low hydration components of cement in sludge water and components that are considered not to be hydrated have a lower specific gravity than unhydrated components of cement, and have developed the present invention. Reached.

In order to achieve the above object, the configuration of the present invention will be explained based on FIG. 1 and FIG. 2 corresponding to an embodiment.

The method for regenerating fresh concrete washing residue of the present invention includes the first
As shown in the figure, there is a classification step 1 in which the washing residue of fresh concrete is wet-classified to remove gravel G and sand S and sludge water H is taken out, and this sludge water H is highly concentrated with cement unhydrated as the main component. A step 2 of concentrating sludge water to separate it into sludge water KH and separated liquid B, a step 5 of storing separated liquid to create a supernatant water tank by storing the separated liquid B, and a step 5 of storing the separated liquid B to create a supernatant water tank, and the high concentration sludge water is Concentration adjustment step 3 in which KH is diluted and adjusted to sludge water J with a predetermined concentration, and sludge water J with a predetermined concentration is vibrated and pulverized in a vibrating ball mill to form sludge fine particles whose main component is unhydrated cement. The method is characterized in that it includes a pulverization step 4 for obtaining slurry M.

Furthermore, the apparatus for recycling fresh concrete washing residue of the present invention has the following features:
As shown in Fig. 2, a classifier 10 extracts sludge water H from which gravel G and sand S have been removed by wet-classifying fresh concrete washing residue, and a classifier 10 extracts sludge water H from which gravel G and sand S have been removed by wet-classifying fresh concrete washing residue. A concentrator 20 that continuously separates high concentration sludge water KH and separated liquid B as components, a separated liquid storage tank 37 that stores the separated liquid B, and a supernatant water of this separated liquid storage tank 37. a concentration adjustment tank 3 for diluting the high concentration sludge water KH and adjusting it to sludge water J of a predetermined concentration;
0, and a vibrating ball mill 40 for vibrating and pulverizing the sludge water J of the predetermined concentration to obtain a slurry M of sludge fine particles containing unhydrated cement as a main component.

[Function] The sludge water H taken out by the classifier 10 is continuously separated by centrifugal force into the high concentration sludge water KH containing unhydrated cement as a main component and the separated liquid B in the concentrator 20. The high-concentration sludge water KH is directly supplied to the concentration adjustment tank 30, and the separated liquid B is a suspended solid containing hydrated components of cement and components that are considered not to be hydrated.
The separated liquid is stored in the separated liquid storage tank 37.

The supernatant water of the separated liquid stored in the separated liquid storage tank 37 is supplied to the concentration adjustment tank 30 to adjust the high concentration sludge water KH to a predetermined concentration, and then it is vibrated and pulverized by the vibrating ball mill 40 to form a cement-free mixture. Sludge fine particles with a higher hydrate content are obtained.

[Example] Next, an example of the present invention will be described in detail based on the drawings.

As shown in FIGS. 2 and 3, the fresh concrete washing water 12 generated when washing the ready-mixed concrete transport vehicle or the ready-mixed concrete mixer vehicle 11 is filtered through the wedge filter 13.
and a classifier 10 consisting of a spiral classifier 14
It is wet classified into gravel G, sand S, and sludge water H.

That is, the washing water 12 is collected in a recovery tank 15, and pumps 15a installed at the bottom of this recovery tank 15 are used to drain the pipe 1.
6 and is supplied to a wedge filter 13, where gravel G is removed. Gravel G is stored in tank 13a. Washing water from which gravel G has been removed is supplied to a spiral classifier 14, where it is classified into sand S and sludge water H. Sand S is stored in tank 14b. The sludge water H is a suspension in which water is used as a dispersion medium and sludge consisting of unhydrated cement and hydrated cement is used as a dispersed phase. The sludge is refluxed into the sludge tank.

The supernatant water in the recovery tank 15 is sent to the sludge tank 24 through the pipe 17 and the cyclone 18 by the pump 15b. The remaining sand is separated by a cyclone 18 and returned to the spiral classifier 14.

A liquid level switch 15c is turned on when the water level in the recovery tank 15 reaches a predetermined level, driving the pump 15b to rotate.

While stirring the sludge water H at a low speed with the agitator 24a in the sludge water tank 24 to prevent the sludge water H from hardening, the sludge water H at the bottom with a sludge concentration of about 5% is pumped into the pipe 26 by the pump 25.
and is sent to the concentrator 20. 24b is a liquid level switch which is turned on when the sludge water tank 24 reaches a predetermined water level, causing the pump 25 to rotate.

The concentrator 20 includes an outer bowl 5o, an inner screw 60, a feed vibe 7o, a gear box 8o, and a casing 85.
It consists of a centrifugal sedimentation machine equipped with Outer body bowl 50
A cylindrical portion 51 and a conical portion 52 are integrally formed, and both ends thereof are rotatably supported by bearings 53 and 54, and a first outlet 56 is provided on the larger diameter side and a second υ outlet hole 57 is provided on the smaller diameter side.
and are provided respectively. The inner barrel screw 6o is provided with a discharge port 62 in a barrel to which a screw blade 61 is fixed, and is rotatably supported within the cylindrical portion 51 and the conical portion 52.

Further, the feed pipe 7o is arranged inside this body, and the sludge water sent from the pipe line 26 is fed to the inner body screw 60.
to be introduced within. The casing 85 encloses the outer bowl 50 and has a separated liquid outlet 86 and a second discharge hole 5 on the side of the first discharge hole 56.
A high concentration sludge water outlet 87 is provided on each side.

Gear box 80 consists of a planetary gear set driven by pulley 81. This gear box 80 has the outer body bowl 5
0 and the inner barrel screw 60 are driven in the same rotational direction while giving a rotational difference so that the rotational speed of the inner barrel screw 60 is slightly smaller than the rotational speed of the outer barrel bowl 50. During this drive, the sludge water H sent by the pump 25 is sent from the feed pipe 70 of the concentrator 20 to the inner barrel screw 60.
When the sludge water is introduced into the sludge water, the sludge mainly composed of unhydrated cement having a high specific gravity is deposited on the inner wall surface of the cylindrical portion 51 of the outer bowl 50 due to centrifugal force (FIG. 3). This sludge transfers to the conical part 52 as shown by the arrow by the rotation of the screw blade 61 of the inner barrel screw 60, passes through the second discharge port 57, and reaches a sludge concentration of 60~
The sludge water is discharged from the outlet 87 in the form of 70% high concentration sludge water KH.

On the other hand, the liquid B separated by the sludge content contains the hydrated components of cement with a small specific gravity in the sludge water and the components that do not seem to be hydrated.
), and is discharged from the outlet 86 through the first discharge port 56 and sent to the separation liquid storage tank 37 through the pipe line 27.

The high concentration sludge water KH discharged from the outlet 87 is transferred to the conduit 3.
1 and stored in the concentration adjustment tank 30 located directly below the outlet 87. The supernatant water of the separated liquid in the separated liquid storage tank 37 is supplied by the pump 33 through the pipe line 34 to the concentration adjustment tank 30, and is stirred by the agitator 30a to dilute the high concentration sludge water KH to sludge water J of a predetermined concentration. be done.

In this example, the sludge concentration is 30% to 40% based on the measured value of the sludge concentration at the outlet 30b of the adjustment tank 30.
Adjusted within the range of %. When the sludge concentration reaches a predetermined concentration, the pump 35 sends sludge water J having a predetermined concentration to the vibrating ball mill 40 through the pipe line 36.

This sludge water J is vibrated and pulverized by a vibrating ball mill 40. In this example, the vibratory ball mill 40 consists of a first stage mill 40a and a second stage mill 40b. The vibration-pulverized slurry M is sent to the slurry storage tank 42, and is stored therein while being prevented from hardening by an agitator 42a. The dispersed phase of this slurry M becomes sludge fine particles with a higher content of unhydrated cement. By sending the required amount of the sludge particles to the plant mixer using the metering pump 43 and adding them to new cement to prepare fresh concrete, the washing residue of the fresh concrete can be effectively used.

The separated liquid stored in the separated liquid storage tank 37 is pumped by a pump 38.
It passes through a conduit 39 and is used for cleaning fresh concrete deposits from a fresh concrete transport vehicle or a fresh concrete mixer vehicle 12 or the like. Here, the hydrated components of the cement contained in the separated liquid and the components considered not to be hydrated are adsorbed to gravel and sand and stored in the tank 13a or 14a, respectively.

According to the reproducing apparatus of the above embodiment, Japanese Patent Application Laid-Open No. 62-2048
Compared to the regeneration device of Publication No. 67, the content of unhydrated cement could be increased by 2 to 3 times or more.

[Effects of the Invention] As mentioned above, conventionally, concentrated sludge water contained cement hydration components and components that are considered not to be hydrated in addition to unhydrated cement. According to the present invention, the content of unhydrated cement in finely pulverized sludge particles cannot be sufficiently improved, but according to the present invention, hydrated components of cement and components that are considered not to be hydrated are removed by suspended solids ( Since it is contained in the separated liquid as a suspended solid (Sus-pended 5 solid) and not contained in the high concentration sludge water, it is possible to further improve the content of unhydrated cement in the sludge fine particles pulverized with a vibrating ball mill. As a result, the quality of concrete using the sludge fine particles of the present invention can be stably improved, and the amount of new cement can be reduced.

In particular, since the concentrator of the present invention can continuously concentrate sludge water to a high concentration, the efficiency of concentrating sludge water is high, the concentration can be easily adjusted, and the regeneration efficiency of the entire apparatus can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining the method for recycling fresh concrete washing residue according to the present invention. FIG. 2 is a block diagram of an apparatus for recycling fresh concrete washing residue according to an embodiment of the present invention. Figure 3 is an enlarged sectional view of the main parts of the concentrator. H: sludge water, KH: high concentration sludge water, B: separated liquid, L: supernatant water, J: sludge water with predetermined concentration, M Nislurry 10: classifier, 20: concentrator, 30: concentration adjustment tank, 37: Separated liquid storage tank, 40: Vibrating ball mill, 50: Outer bowl, 51: Cylindrical part, 52: Conical part, 53.54: Bearing, 56: First discharge port, 57: Second discharge port, 60: Inner body screw 61 varnish screw, 62: discharge port, 70: feed pipe, 80: gear box, 85: casing, 86: separated liquid outlet, 87: highly concentrated sludge water outlet.

Claims (1)

[Scope of Claims] 1) A classification step of wet-classifying fresh concrete washing residue to remove gravel and sand and extracting sludge water; a step of concentrating sludge water to separate it into a separated liquid; a separating liquid storage step of storing the separated liquid to produce supernatant water; and diluting the highly concentrated sludge water with the supernatant water to obtain sludge water of a predetermined concentration. and a pulverization step of vibrating and pulverizing sludge water of a predetermined concentration using a vibrating ball mill to obtain a slurry of sludge particles containing unhydrated cement as a main component. How to play. 2) The method for recycling fresh concrete washing residue according to claim 1, wherein the separated liquid is used for cleaning the fresh concrete deposits. 3) A classifier that wet-classifies fresh concrete washing residue to remove gravel and sand and extracts sludge water, and separates this sludge water from high-concentration sludge water mainly composed of unhydrated cement using centrifugal force. a concentrator that continuously separates the separated liquid, a separated liquid storage tank that stores the separated liquid, and a concentration that adjusts the high concentration sludge water to a predetermined concentration by diluting the high concentration sludge water with supernatant water of the separated liquid storage tank. An apparatus for regenerating fresh concrete washing residue, comprising a regulating tank and a vibrating ball mill that vibrates and pulverizes the sludge water of a predetermined concentration to obtain a slurry of fine sludge particles containing unhydrated cement as a main component. 4) The concentrator has a cylindrical part and a conical part integrally formed,
The outer body bowl is rotatably supported by bearings at both ends and has a first discharge port on the large diameter side and a second discharge port on the small diameter side, and a discharge port is provided in the body to which the screw blade is fixed. is,
and an inner screw rotatably supported within the cylindrical portion and the conical portion, a feed pipe for introducing sludge water taken out from the classifier into the inner screw, the outer bowl and the inner screw. a gear box that provides a rotational difference such that the rotational speed of the inner screw is slightly smaller than the rotational speed of the outer bowl in the same direction; and a gear box that encloses the outer bowl and is separated to the first discharge port side. 4. The apparatus for recycling fresh concrete washing residue according to claim 3, comprising a liquid outlet and a casing provided with a high concentration sludge water outlet on the second discharge port side.