JP2000140818A - Treatment of waste of ready-mixed concrete plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the danger of environmental disruption and to reduce treating cost in the treatment of the waste ready-mixed concrete remaining in the drum of a mixermobile. SOLUTION: When only a small amt. of ready-mixed concrete remains in the drum 3 of the mixermobile 1b returned to a ready-mixed concrete plant, the inside of the drum 3 is cleaned, the aggregate such as ballast and sand is separated and recovered from the waste ready-mixed concrete discharged along with the cleaning water, the slurry is dehydrated by a filter press or sun-dried, and the waste 17 freed from water is transiently stored in the plant. When a large amt. of the waste is left, the waste generated in the small-amt. treating stage is put into the drum of the mixermobile 1b, the drum is rotated, hence the waste is kneaded with the waste ready-mixed concrete, and the kneaded material is discharged from the drum, solidified and recovered as a rigid solid 37.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating waste produced in a ready-mixed concrete factory by treating waste ready-mixed concrete remaining in a drum of a mixer truck.

[0002]

2. Description of the Related Art A mixer truck that returns ready-mix concrete to a ready-mixed concrete factory after transporting ready-mixed concrete to a civil engineering construction site inputs washing water to wash away the ready-mixed concrete adhering to the inside of the drum, and mixes with the washing water. The ready-mixed concrete discharged from the drum is conventionally led to a collecting device such as a trommel or an inclined sieve to separate and collect gravel and the like, and further guided to a collecting device such as a classifier to separate and collect sand and the like. Is introduced into a stirring tank to collect supernatant water, and the slurry (sludge water) stored in the stirring tank is pumped to a filter press by a high-pressure pump to be dehydrated and treated as cake.

[0003] In addition, among the mixer trucks returned from a civil engineering construction site, there are many cases where a large amount of the ready-mixed concrete remains in the drum without returning enough of the used ready-mixed concrete to return. Even in such a case, in the past, the remaining ready-mixed concrete had to be treated by the above-described method, so that the filter cake was generated in a large amount.

[0004]

By the way, the filter cake discharged from the filter press as described above consists of fine particles of cement hydrate and is easily dispersed when dumped into the sea or the ground as it is. Conventionally, an appropriate processing method has not been established, which may cause environmental destruction. Therefore, in order to dispose of the filter cake, a controlled disposal site that can prevent its dispersion is required,
For this reason, the processing cost is very high.

[0005]

SUMMARY OF THE INVENTION A method for treating waste in a ready-mixed concrete factory according to the present invention is intended to solve the above-mentioned problem, and waste mixed concrete remaining in a drum of a mixer truck returned to a ready-mixed concrete factory. The process consists of a small-volume processing step performed when the amount is small or substantially absent, and a large-volume processing step performed when a large amount of waste ready-mixed concrete remains in the drum of the mixer truck returned to the ready-mixed concrete factory. After the waste ready-mixed concrete remaining in the drum of the mixer truck is separated from the waste ready-mixed concrete discharged together with the washing water when the inside of the drum of the mixer truck is washed, aggregates such as gravel and sand are separated and collected. The slurry is temporarily stored in the factory as dewatered waste by dehydrating it with a filter press or drying it in the sun. In the treatment step, the waste generated in the small-amount treatment step is put into a drum of a mixer truck, and the drum is rotated to knead with the waste ready-mixed concrete, and then discharged from the drum and solidified. It is characterized by being recovered as a solid solid.

[0006]

Embodiments of the present invention will now be described with reference to the drawings. First, the small amount processing step will be described. This small-volume processing step is performed when the amount of waste ready-mixed concrete remaining in the drum of a mixer truck (also called an agitator truck) returned from a civil engineering construction site or the like is substantially zero or small. Can be In this case, as shown in FIG. 1, the mixer truck 1 a cleans the inside of the drum 3 by charging the washing water 4 into the drum 3 in the car wash area 2. At that time, the waste ready-mixed concrete discharged together with the washing water from the drum 3 is temporarily stored in a recovery tank 5 and is sent to the screw conveyor type classifier 8 through the pipe 7 by the submersible pump 6. The classifier 8 is made of gravel,
Aggregates 9 such as sand are separated and collected in a sand yard 10.

Reference numeral 11 denotes a stirring tank provided for storing a slurry (sludge water) containing the remaining cement hydrate separated from the aggregate by the classifier 8, and the stirring tank 11 In order to prevent this, a stirring blade 12 is provided. Then, the slurry stored in the stirring tank 11 is sucked into the receiver tank 14 by the submersible pump 13, and is further fed to the filter press 16 by the high-pressure pump 15 to be dehydrated. At this time, the waste 17 as the cake (dehydrated cake) formed in the filter press is stored in the cake storage 18. The filtered water discharged from the filter press 16 is stored in a supernatant water tank 19, pumped by a submersible pump 20, and reused as washing water 4 of the mixer truck 1a or for other uses. Therefore, in this small-quantity treatment process, a large amount of waste 17 gradually accumulates in the factory.

On the other hand, the mass treatment process is carried out when a large amount of ready-mixed concrete that needs to be discarded remains in the drum of the mixer truck returned from the site of civil engineering construction or the like. The accumulated waste 17 is removed by a power shovel 30 as shown in FIG.
Carry inside. Then, the blades 32 of the stirrer are rotated, and the waste 17 is previously made muddy by this stirring. Then, by driving a tube pump (also called a squeeze pump) 33, the waste 17 is put into the drum 3 of the mixer truck 1b in which the ready-mixed concrete remains.
Water may be added to the stirrer 31 so that the waste 17 has an appropriate amount of water. The amount of the waste 17 charged into the drum 3 is, for example, about １ ／ to ３ of the amount of the ready-mixed concrete remaining in the drum 3 and is increased or decreased according to the remaining amount. Thus, the waste 17 and the waste ready-mixed concrete charged into the drum 3 are kneaded well by rotating the drum 3. Then, the mixer truck 1b is moved to the discharge place 34, and the kneaded material is discharged from the drum 3 to the discharge place 34. When the discharged material 35 thus discharged is left for about 24 hours to be substantially solidified, it is moved to the solidification site 36 using the power shovel 30 and left for 4 to 5 days in the solidification site, whereby the water of the waste ready-mixed concrete is removed. Solid solid 37 by sum reaction
To solidify. The mixing ratio between the waste 17 and the ready-mixed concrete is determined in consideration of the mechanical strength and the like required for the solid material 37. However, in order to increase the strength, a new cement or blast furnace slag, quick lime is used. , Slaked lime, fly ash, etc. may be added.

After discharging the kneaded material of the waste ready-mixed concrete and the waste 17 from the drum 3 of the mixer truck 1b in the mass treatment process, the mixer truck 1b is moved to the car washing place 2 shown in FIG. Then, the inside of the drum 3 is washed. Then, aggregates such as gravel and sand are separated and collected from the waste ready-mixed concrete discharged together with the washing water in the same manner as described in the small-amount treatment step, and the slurry is filtered from the stirring tank 11 into a filter press 16. The waste 17 from which water is removed by dehydration and discharge is provided, and the waste 17 is temporarily stored until the next large-scale processing step can be performed.

The solid material 37 has a uniaxial compressive strength of 8 N / m.
can be the m ² or more, not fear that fine particles are dispersed in water or the ground as filter cake be dumped directly, relatively becomes no risk of environmental damage so-called stabilized waste It can be disposed of at low cost.

Further, if the discharged material 35 from the drum 3 is filled in a mold having an appropriate shape, a concrete product having a desired shape such as a brick block can be formed. In this way, the waste 17 produced in the ready-mixed concrete factory is consumed for producing concrete products as appropriate, so that there is no need to dispose of the waste as industrial waste outside the factory, and various costs associated with disposal are eliminated. And the possibility of environmental pollution can be eliminated.

Further, in order to effectively use as a roadbed material, recycled aggregate, or a gap filling material used when backfilling fume pipes or the like in the ground, the solid matter 31 formed in the solidification site 36 is pulverized. In doing so, the solids 31 are transferred by a power shovel 30 to a crushing and classifying device as exemplified in FIG. In the figure, 40 is a jaw crusher provided so that a movable plate 42 can be opened and closed with respect to a fixed plate 43 by a hydraulic cylinder 41, 44 is a fixed-quantity feeder provided on the jaw crusher, 45 is a hopper, The solid matter 31 charged into the hopper 45 by the shovel 30 is pulverized by the jaw crusher into a lump having a diameter of 40 mm or less. The pulverized solid material 31 is conveyed to a vibrating sieve 47 by a belt conveyor 46, where the fine sand 48 having a diameter of 5 mm or less and a lump 4 having a diameter of 5 mm or more
Classified into 9 and used for recycled aggregate, roadbed material, etc.

In this embodiment, the water is removed by dewatering the slurry by a filter press in the small-volume processing step. However, the slurry is spread on the ground such as a factory site without passing through the filter press. Dehydrated sludge from which water has been removed by day drying,
The waste can be stored in the factory until the next large-scale processing step is performed.

[0014]

As described above, in the waste treatment method of the ready-mixed concrete plant according to the present invention, the waste generated in the small-quantity treatment process is put into the drum of the mixer truck in the large-scale treatment process and is rotated and kneaded. After that, this is discharged from the drum and solidified by recovering the solid, so that fine particles may be dispersed as in the case where waste such as filter cake or dewatered sludge is directly discarded. Since there is no risk of environmental destruction, processing is easy and costs can be greatly reduced, and beneficial effects such as being able to be used for roadbed materials, etc., or molded into concrete products and reused are also possible. is there.

[Brief description of the drawings]

FIG. 1 is a schematic view of a small-quantity treatment step in a waste treatment method of a ready-mixed concrete plant according to the present invention.

FIG. 2 is a schematic diagram of a large-scale treatment step in the waste treatment method for a ready-mixed concrete plant according to the present invention.

FIG. 3 is a side view of a crushing and classifying device for crushing solids.

[Explanation of symbols]

 1a, 1b Mixer car 2 Car wash 3 Drum 4 Wash water 8 Classifier 9 Aggregate 11 Stirrer tank 16 Filter press 17 Waste 31 Stirrer 33 Tube pump 34 Discharge place 35 Discharge 36 Solidification place 37 Solid matter

Claims (1)

[Claims] 1. A small-quantity treatment step to be performed when a small amount or substantially no waste ready-mixed concrete remains in a drum of a mixer truck returned to a ready-mixed concrete plant, A large-scale treatment step is carried out when a large amount of waste ready-mixed concrete remains.The small-quantity treatment step includes washing water when the waste ready-mixed concrete remaining in the drum of the mixer truck is washed in the drum of the mixer truck. After separating and recovering aggregates such as gravel and sand from the waste ready-mixed concrete discharged, the slurry is dewatered with a filter press or dried in the sun to temporarily remove water as waste to the factory. On the other hand, in the large-volume processing step, the waste generated in the small-volume processing step is put into a drum of a mixer truck and the drum is rotated. And then kneading the waste ready-mixed concrete with the waste ready-mixed concrete, and then discharging the solid from the drum to solidify and recover the solid as a solid product.