JP6480734B2 - Heavy liquid and specific gravity sorting method - Google Patents

Description

  The present invention relates to a specific gravity sorting method for separating contaminants composed of wood pieces, plastic pieces, garbage, etc., which are not suitable for concrete aggregates from collected gravel, and a heavy liquid used therefor.

  The gravel collected as aggregate for concrete usually contains contaminants such as wood pieces, plastic pieces, and garbage that are not suitable for use as the aggregate. For this reason, conventionally, the collected gravel has been immersed in water, the contaminants having a specific gravity smaller than that of water are raised on the surface of the water (specific gravity selection), and this is removed (Patent Documents 1 to 3 below) 3).

JP-A-8-155330 JP-A-8-187448 JP 2001-96186 A

  By the way, when the collected gravel is, for example, riverbed gravel, the collected gravel contains wood fragments containing the mud of the riverbed and thus having a specific gravity greater than that of water. Since such a piece of wood does not float on the water surface, it cannot be removed by specific gravity sorting using water.

  An object of the present invention is to use a specific gravity selection method for separating contaminants such as mud-containing wood pieces having a relatively high specific gravity contained therein from gravel collected as aggregate for concrete and the like. It is to provide a heavy liquid.

Wood In the present invention, a mixed harvested gravel (the collecting gravel) and sorted gravel are those suitable for aggregate for concrete, it is not suitable for the aggregate, in the collecting gravel, Heavy liquid used for specific gravity separation to separate plastic fragments, garbage, and contaminants consisting of all or part of wood pieces containing mud is smaller than the specific gravity of the selected gravel and larger than the specific gravity of the contaminants It consists of cement milk having a specific gravity, to which the selected gravel is settled and to which the contaminants are floated, and to which a retarder for delaying hardening is added.

According to the present invention, there is provided a retarder for delaying hardening, wherein the heavy liquid has a specific gravity smaller than the specific gravity of the selected gravel and larger than the specific gravity of the contaminants, causes the selected gravel to settle and floats the contaminants. Since it consists of added cement milk, when it is used for specific gravity sorting of the collected gravel, it is lower than the heavy liquid consisting of the cement milk as a contaminant that is not suitable for the aggregate for concrete existing in the collected gravel. In addition to specific gravity wood pieces, plastic pieces, etc., mud-containing wood pieces having a higher specific gravity can also float on the heavy liquid surface . The magnitude of the specific gravity of the cement milk can be determined in consideration of the type of contaminants contained in the collected gravel, the magnitude of the specific gravity, and the like.

Specific gravity sorting for the collected gravel using heavy liquid consisting of the cement milk , the heavy liquid is stored in a tank, and then the collected gravel is put into the heavy liquid in the tank, and the collected gravel of the collected gravel Mixed in the collected gravel that has settled in heavy liquid in the tank and that is suitable for aggregate for concrete, and that is not suitable for aggregate that has floated in the heavy liquid. Wood pieces, plastic pieces, garbage, and contaminants consisting of all or part of wood pieces containing mud are taken out from the tank. The heavy liquid is supplied into the tank using a normal liquid pump for a heavy liquid having a relatively low viscosity, and using a concrete pump for a heavy liquid having a relatively high viscosity, for example. Can do.

According to the present invention, it is possible to use, as the aggregate for concrete, selected gravel that has settled in the heavy liquid composed of the cement milk in the tank out of the collected gravel extracted outside the tank. The selected gravel taken out of the tank can be washed with fresh water to remove the heavy liquid adhering to it as necessary. The cement milk may contain a dispersant added to reduce its viscosity .

It is a figure which shows roughly the specific gravity selection method which concerns on this invention.

  Referring to FIG. 1, the collected gravel (collected gravel) 10 is subjected to specific gravity sorting using heavy liquid 12, and gravel (sorted gravel) 14 that is suitable for aggregate for concrete, and the aggregate One form for carrying out the method of separating the mixture 16 from the wood chips, plastic pieces, garbage, wood pieces containing mud, etc. mixed in the collected gravel, which is not suitable, is conceptually shown. .

  The collected gravel 10 is transported toward the tank 20 in which the heavy liquid 12 is stored in advance by using a transport device 18 such as a belt conveyor for the specific gravity selection, and the inside of the tank 20 is passed through the hopper 22. Into the heavy liquid 12. The illustrated hopper 22 extends vertically inside and outside the tank 20 through the top of the tank 20, and is immersed in the heavy liquid 12 at a part below the hopper 22.

  The heavy liquid 12 used for the specific gravity selection has a specific gravity greater than the overall specific gravity of the collected gravel 10 when immersed in water (fresh water) (that is, the specific gravity of the mixture of the collected gravel 10 and the water). Have. The heavy liquid 12 is an aqueous solution containing, for example, salt, bentonite, barium sulfate, or cement as an ingredient, and is composed of an aqueous solution having a specific gravity of 1.1 to 2.0. The components of the aqueous solution and the magnitude of the specific gravity can be determined in consideration of the location where the collected gravel 10 is collected, the type of the contaminant 16 mixed in the collected gravel 10, the magnitude of the specific gravity, and the like. The specific gravity of the contaminant 16 can be known in advance by measurement.

  The heavy liquid 12 is stored in a container 24 disposed outside the tank 20. The heavy liquid in the container 24 is sent to the tank 20 by the operation of a pump 28 attached to the pipe 26 through the pipe 26 connected to the container and the tank 20, and is stored in the tank 20. When the heavy liquid 12 has a relatively small viscosity, the pump 28 and the pump 38 described later can be composed of a liquid pump such as an axial pump. Further, when the heavy liquid 12 has a relatively high viscosity, the pump 28 and the pump 38, which will be described later, can be made of, for example, a concrete pump.

  The collected gravel 10 placed in the heavy liquid 12 stored in the tank 20 and immersed in the heavy liquid 12 has a lower density than that of the heavy liquid 12 among the components constituting the collected gravel. On the other hand, the one that is larger than the specific gravity of the heavy liquid 12 floats toward the liquid surface and settles in the heavy liquid 12 toward the bottom of the heavy liquid.

  Among the collected gravel 10, the one that floats on the heavy liquid surface is the contaminant 16, and the one that settles on the heavy liquid bottom is the selected gravel 14. When the heavy liquid 12 has a relatively high viscosity, the heavy liquid 12 acts to prevent the contaminant 16 from rising. Therefore, preferably, the tank 20 or the later-described transfer device 42 in the tank 20 is vibrated to cause the heavy liquid 12 in the tank 20 to vibrate. Thereby, the contaminant 16 in the heavy liquid 12 can be made to float easily.

  The contaminant 16 is discharged onto a screen 30 installed outside the tank 20 together with a part of the heavy liquid 12 overflowing outside the tank 20 through an opening 29 provided on the side of the tank 20. It is taken out. In the example shown in the figure, a guide plate 40 that is inclined downward from the opening 29 of the tank 20 toward the screen 30 positioned therebelow is disposed, and the contaminants 16 pass through the guide plate 40 and on the screen 30. To. Further, in the illustrated example, the screen 30 is placed in an inclined state downward, and the contaminants 16 discharged and deposited on the screen 30 are slid down or slid down on the ground 32.

  Further, when part of the heavy liquid 12 adhering to the discharged contaminant 16 is on the screen 30, it drops through the screen. A portion of the heavy liquid 12 to be dripped is stored in a liquid receiving container 34 installed below the screen 30, and through a pipe 36 connected to the liquid receiving container 34, the pump 38 attached to the pipe 36 is operated. The heavy liquid 12 is returned to the container 24.

  On the other hand, the sorted gravel 14 is transferred from the inside of the tank 20 to the outside thereof, and is thereby taken out of the tank 20. A transfer device 42 including a bucket conveyor and a belt conveyor is disposed in the tank 20 for transferring the sorted gravel 14. The transfer device 42 extends obliquely upward in the tank 20 from the bottom to the top of the tank, and protrudes outside the tank 20 through an opening 44 provided at the top of the tank 20 at the tip. Most of the transfer device 42 is immersed in the heavy liquid 12 in the tank 20.

  According to this, the separated gravel 14 that has settled in the heavy liquid 12 and is in the process of being settled is drawn onto the transfer device 42 and dropped, and sent from the inside of the tank 20 to the outside of the tank, and finally , Fall from the transfer device 42 onto the ground 32 and accumulate.

  Since the heavy liquid 12 has a specific gravity greater than that of the mixture (the mixture of the collected gravel 10 and water), the contaminant 16 contained in the collected gravel 10 is reduced in specific gravity compared to the conventional specific gravity sorting with water. A wider range of separations can be made above and on the type. In addition, it is possible to remove the contaminant 16 having a relatively high specific gravity, such as the mud-containing piece of wood, from which the specific gravity selection with water was impossible, from the collected gravel 10.

  In order to remove a part of the heavy liquid 10 adhering to the sorted gravel 10 discharged to the outside of the tank 20, for example, immediately after being discharged from the front end of the transfer device 42, fresh water 46 is sprayed on this and washed. can do. Moreover, when using the aqueous solution (cement milk) which uses the said cement as a heavy liquid 12, the retarder for delaying the hardening, the dispersing agent for reducing the viscosity of the said aqueous solution, etc. in the said aqueous solution Can be added.

10 Gravel (collected gravel)
12 Heavy liquid 14 Gravel (sorted gravel)
16 Contaminant 20 Tank 24 Container for heavy liquid 46 Fresh water

Claims (4)

The collected gravel and sorted gravel are those suitable for aggregate for concrete, it is not suitable for the aggregate, wood chips mixed in the collected gravel, pieces of plastic, dirt, and mud A heavy liquid used for specific gravity sorting to separate into all or a part of the wood pieces it contains ,
A weight consisting of cement milk having a specific gravity smaller than the specific gravity of the sorted gravel and greater than the specific gravity of the contaminants, and having added a retarder for delaying hardening, which causes the sorted gravel to settle and float the contaminants. liquid. The heavy liquid according to claim 1, wherein the cement milk includes a dispersant added to reduce its viscosity . Storing the heavy liquid according to claim 1 or 2 in a tank;
Throwing gravel collected in heavy liquid in the tank,
Of the collected gravel, settled in heavy liquid in the tank, selected gravel that is suitable for aggregate for concrete, and floated in the heavy liquid, which is not suitable for the aggregate, A specific gravity sorting method, comprising: taking out pieces of wood, plastic pieces, garbage, and contaminants composed of all or part of wood pieces containing mud, which are mixed in the collected gravel , respectively, out of the tank. The harvested gravel is Ru riverbed gravel Tona, gravity separation method according to claim 3.

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