Manufacturing method of carbonized granular aggregate and carbonized recycled aggregate of residual concrete / return concrete and manufacturing device thereof

Abstract

To achieve immobilization of carbon dioxide and effective utilization of resources by absorbing and fixing carbon dioxide in residual concrete / return concrete that have conventionally been treated and discarded, and converting the same into granular aggregates or recycled aggregates to facilitate reuse.SOLUTION: A device includes a first frustum cylindrical body 5 provided with an entry / exhaust port 6 on a truncated side; a second frustum cylindrical body 8 with a rotation driving device 4 connected on a truncated side; a cylindrical rotation drum 3 connected to each bottom face of the cylindrical bodies; and a mixing blade 2 formed spirally on an inner face of the rotation drum 3. In the method, a residual concrete / return concrete is directly used, or used as a recycled aggregate previously solidified and crushed from a residual concrete / return concrete; carbon dioxide gas is introduced into the rotation drum 3; the rotation drum 3 is rotated; and carbon dioxide is immobilized in the granulated aggregate or recycled aggregate formed by the device.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a technology for absorbing and fixing carbon dioxide in concrete to reduce carbon dioxide, and particularly to a method for manufacturing carbonated granular aggregate and carbonated recycled aggregate of residual concrete (residual concrete) and return concrete (return concrete), which can be brought back to a fresh concrete factory without being used at a construction site, and an apparatus for manufacturing the same, when treating the same.

Background Art

[0002] Since the agreement of the Kyoto Protocol in 1997 and the SDGs in 2015, the international community has been promoting efforts towards "decarbonization and CO2 reduction" from before. As one of the measures against global warming, reduction of carbon dioxide emissions from facilities using fossil fuels is required.

[0003] Carbon dioxide can be absorbed and fixed by using concrete or its waste materials. Concrete produced by mixing water with cement obtained through a firing process of heating limestone at 1,400°C or higher, fine aggregate (sand, crushed sand), and coarse aggregate (gravel, crushed stone) is calculated to be produced by emitting 329 kg of carbon dioxide CO2 per cubic meter, and is said to account for 8% of the annual global carbon dioxide emissions. 3 Calcium hydroxide contained in concrete has the property of taking in carbon dioxide in the air, and per cubic meter

[0004] 3 ​It can fix approximately 200 kg of carbon dioxide per square meter at most. The state in which this carbon dioxide is absorbed (fixed) in concrete is called "White Carbon". The carbon dioxide taken into the marine ecosystem, that is, "Blue Carbon", is estimated to be 5.83 billion tons per year, and the carbon dioxide "Green Carbon" taken into the terrestrial ecosystem is estimated to be 10.64 billion tons. "White Carbon" is estimated to be 1 billion tons. By innovating in CCS (Carbon dioxide Capture and Storage, a technology for storing carbon dioxide underground) and CCUS (Carbon Capture, Utilization and Storage, a technology for immobilizing or effectively using high-concentration carbon dioxide) in the cement and concrete industry, it is said that it is possible to contribute to a decarbonized society by suppressing carbon dioxide emissions and further utilizing carbon dioxide CO2.

[0005] Various technologies have been proposed to reduce the emissions of carbon dioxide derived from the combustion of this fossil fuel. For example, like the Japanese Patent Application Laid-Open No. 2023-114338 of Patent Document 1, "Cement-based composition, method for producing cement-based composition, and carbon dioxide recovery method", a heating step of heating the area where the cement-based composition having the ability to absorb carbon dioxide is constructed and releasing carbon dioxide from the constructed cement-based composition to regenerate the ability to absorb carbon dioxide, and a recovery step of recovering the carbon dioxide released in the heating step are provided. A method for regenerating the carbon dioxide absorption ability and recovering the released carbon dioxide has been proposed.

[0006] Also, at the construction site, when not all of the fresh concrete in the drum of the agitator truck is used, "leftover concrete", which is the remaining concrete, is generated. Alternatively, it may take more than a predetermined conveyance time for the agitator truck to reach the construction site from the concrete manufacturing plant, or it may take time to place the fresh concrete at the construction site, so that the setting reaction progresses and the fluidity is gradually lost, resulting in "returned concrete" that can no longer be used.

Prior Art Documents

Patent Document

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] In Patent Document 1, it is stated that a carbon dioxide - absorbing cement - based composition (for example, demolished concrete) that has lost or reduced its ability to absorb carbon dioxide is heated to regenerate (restore) its ability to absorb carbon dioxide. However, when heating the carbon dioxide - absorbing cement - based composition, carbon dioxide is often generated in the means of generating heat, so there was a problem that it did not reduce carbon dioxide emissions in total.

[0009] Residual concrete and returned concrete were originally purchased by the construction site and the ownership is with the construction site. However, since there is no processing machine or sufficient processing space at the construction site, it is currently the case that according to business practices, it is returned to the concrete manufacturing factory for processing.

[0010] For example, in the case of the properties of concrete before hardening or solidifying, the processing operations as shown in the flowchart of FIG. 11 are carried out. When residual concrete and returned concrete are subjected to water treatment, they are classified into fine aggregate, coarse aggregate, sludge cake, and supernatant water. Although there are regulations based on the Japanese Industrial Standards (JIS A5308) for raw concrete that fine aggregate, coarse aggregate, and sludge water can be used, in reality, it is rarely used by the purchaser, the construction contractor (general contractor). Although there are examples of its use in local civil engineering works, it is almost non - existent in the city center. The supernatant water can be used with permission at some sites, but the surplus is neutralized and discharged into public sewers, etc. There was a problem that the use of recycled products was not carried out due to concerns that it might lead to a decline in quality.

[0011] In factories without dedicated heavy machinery or crushers, when fresh concrete hardens, the processing can become difficult. Therefore, for the leftover and returned concrete thus discarded, washing and classification processes are deliberately carried out before hardening. On the other hand, in places where there is room on the factory site and the noise of crushers can be tolerated (such as industrial exclusive areas, etc.), fresh concrete is solidified into an appropriate size and crushed and size-adjusted by crushers the day after or later to produce recycled aggregate and recycled roadbed materials for sale. This is common in local-type fresh concrete plants, and the processing is carried out in the steps shown in the flowchart of Fig. 12.

[0012] Thus, leftover and returned concrete mostly occurs after work is completed at the construction site, and there is a problem that the processing requires labor such as personnel, power costs, and time, which is originally unnecessary.

[0013] The inventors of the present invention focused on the fact that leftover and returned concrete that could not be reused could be reused by immobilizing carbon dioxide. Concrete in which a large amount of carbon dioxide is absorbed and fixed becomes chemically stable by carbonation. It was considered that this could be used again as a concrete material. Furthermore, the inventors of the present invention considered that when immobilizing carbon dioxide in leftover and returned concrete, the amount of carbon dioxide fixed could be increased by generating a large amount of calcium hydroxide that fixes carbon dioxide from the concrete.

[0014] The present invention was devised to solve such problems. That is, the object of the present invention is to absorb and fix carbon dioxide in leftover and returned concrete that was conventionally processed and discarded, and to make it into granular aggregate or recycled aggregate so that it can be easily reused, thereby achieving carbon dioxide immobilization and enabling effective utilization of resources. The present invention provides a method for manufacturing carbonated granular aggregate and carbonated recycled aggregate of leftover and returned concrete and its manufacturing apparatus.

Means for Solving the Problems

[0015] The method for producing carbonated granular aggregate of the present invention is a method for producing carbonated granular aggregate of waste concrete and return concrete by immobilizing carbon dioxide in waste concrete and return concrete, comprising: A carbon dioxide immobilization step of charging a fluid waste concrete and return concrete and carbon dioxide gas into a sealed container and bringing them into contact with each other to immobilize carbon dioxide in the waste concrete and return concrete; A granulation step of shaping the waste concrete and return concrete into granules in the sealed container, and characterized in that the carbonated granular aggregate in which carbon dioxide is immobilized is used as a raw material for fresh concrete.

[0016] The method for producing carbonated granular aggregate of the present invention is a method for producing carbonated granular aggregate of waste concrete and return concrete by immobilizing carbon dioxide in waste concrete and return concrete, comprising: A water addition step of charging a fluid waste concrete and return concrete into a sealed container and adding water thereto; A carbon dioxide immobilization step of, after the treatment in the water addition step, enclosing carbon dioxide gas in the sealed container, bringing the carbon dioxide gas into contact with the waste concrete and return concrete, and immobilizing carbon dioxide in the waste concrete and return concrete; A granulation step of shaping the waste concrete and return concrete into granules in the sealed container, and characterized in that the carbonated granular aggregate in which carbon dioxide is immobilized is used as a raw material for fresh concrete.

[0017] The method for producing carbonated granular aggregate of the present invention is a method for producing carbonated granular aggregate of waste concrete and return concrete by immobilizing carbon dioxide in waste concrete and return concrete, comprising: A retarder addition step of charging a fluid waste concrete and return concrete into a sealed container and adding a retarder thereto; A carbon dioxide immobilization step of, after the treatment in the retarder addition step, enclosing carbon dioxide gas in the sealed container, bringing the carbon dioxide gas into contact with the waste concrete and return concrete, and immobilizing carbon dioxide in the waste concrete and return concrete; A granulation step of shaping the waste concrete and return concrete into granules in the sealed container, and characterized in that the carbonated granular aggregate in which carbon dioxide is immobilized is used as a raw material for fresh concrete.

[0018] The present invention is a method for manufacturing carbonated granular aggregate of waste concrete and return concrete that immobilizes carbon dioxide in waste concrete and return concrete, and a water addition and retarder addition step of charging fluid waste concrete and return concrete into a sealed container and adding water and a retarder thereto, and a carbon dioxide immobilization step of enclosing carbon dioxide gas in the sealed container after the treatment of the water addition and retarder addition step, bringing the carbon dioxide gas into contact with the waste concrete and return concrete, and immobilizing carbon dioxide in the waste concrete and return concrete, and a granulation step of shaping the waste concrete and return concrete into granules in the sealed container, and is composed of characterized in that the carbonated granular aggregate in which carbon dioxide is immobilized is used as a raw material for fresh concrete. The retarder added in the water addition and retarder addition step is a setting retarder for concrete mainly composed of saccharides such as glucose, lignin sulfonate, oxycarboxylate, silicofluoride, etc.

[0019] Further, the method for manufacturing carbonated recycled aggregate of the present invention is a method for manufacturing carbonated recycled aggregate of waste concrete and return concrete that immobilizes carbon dioxide in waste concrete and return concrete, and a crushing step of solidifying the waste concrete and return concrete and then crushing it into a predetermined size, and a carbon dioxide immobilization step of charging and bringing into contact with the crushed waste concrete and return concrete and carbon dioxide gas in a sealed container, and immobilizing carbon dioxide in the waste concrete and return concrete, and is composed of characterized in that the carbonated recycled aggregate in which carbon dioxide is immobilized is used as a raw material for fresh concrete or a recycled roadbed material. After the crushing step, it is preferable to have a watering step of wetting with water in order to promote the carbon dioxide immobilization of the waste concrete and return concrete.

[0020] The manufacturing apparatus for carbonated granular aggregate and carbonated recycled aggregate of the present invention is a manufacturing apparatus for carbonated granular aggregate and carbonated recycled aggregate that immobilizes carbon dioxide in waste concrete and return concrete, and a charging / discharging port (6), a cylindrical rotary drum (3) provided with a driven mechanism of a rotary drive device (4), and It is provided with a mixing blade (2) formed on the inner surface of a rotating drum. It is configured such that waste concrete and return concrete and carbon dioxide gas are introduced into the rotating drum, and while rotating the rotating drum, carbon dioxide is fixed to the waste concrete and return concrete.

[0021] Or, it is a manufacturing apparatus for carbonated granular aggregate and carbonated recycled aggregate for fixing carbon dioxide to waste concrete and return concrete, A first truncated cone-shaped cylinder body (5) provided with an input / output port (6) at the truncated side, and a second truncated cone-shaped cylinder body (8) having a rotary drive device (4) connected to the truncated side, each having a cylindrical rotating drum (3) connected to the bottom surface of the cylinder body, A mixing blade (2) spirally formed on the inner surface of the rotating drum, It is provided with an input / output lid (7) that is attached to the input / output port so as to be freely opened and closed and enhances the airtightness inside the rotating drum. It is configured such that waste concrete and return concrete and carbon dioxide gas are introduced into the rotating drum from the input / output lid, the rotating drum is rotated, and while fixing carbon dioxide to the waste concrete and return concrete, the waste concrete and return concrete are granulated. The rotating drum is further provided with an inclination drive device (13). When discharging the waste concrete and return concrete to which carbon dioxide is fixed, the rotating drum can be configured to be inclined.

Advantages of the Invention

[0022] In the invention having the above configuration, carbon dioxide can be fixed and resources can be effectively utilized. The waste concrete and return concrete are those that have passed a certain time (for example, 1.5 hours) or more from a concrete manufacturing factory, and the fixation of carbon dioxide is faster when a certain amount of time has passed compared to immediately after manufacturing. When carbon dioxide is brought into contact with the waste concrete and return concrete, an exothermic reaction occurs, and around the coarse aggregate, a mortar layer is formed and fresh concrete is granulated. In this way, it is possible to effectively utilize the waste concrete and return concrete that would originally be discarded, and to fix carbon dioxide while manufacturing granulated aggregate that becomes a new fresh concrete raw material.

[0023] Furthermore, a method is provided in which residual concrete and returned concrete are put into a sealed container, and a water addition step of adding water, or a water addition and retarder addition step of adding water and a retarder is added before enclosing carbon dioxide therein. That is, in a method for generating a large amount of calcium hydroxide that fixes carbon dioxide from concrete, the generation of calcium silicate hydrate and the like in the liquid phase during the initial stage of hydration can be suppressed, and the dissolution amount of calcium hydroxide can be continuously increased. The amount of carbon dioxide fixed can be increased by the effect of increasing the dissolution amount of calcium hydroxide.

[0024] In the production apparatus for carbonated granular aggregate and carbonated recycled aggregate of residual concrete and returned concrete having the above configuration, carbon dioxide can be fixed using a rotating drum (3) such as the drum portion of an agitator truck, and thus the treatment can be performed using simple equipment. As a result, the equipment cost can be kept low, and it becomes possible to produce more efficient and better-shaped carbonated granular aggregate. Also, it becomes possible to produce carbonated recycled aggregate.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0026] The manufacturing method and manufacturing apparatus for carbonated granular aggregate and carbonated recycled aggregate of waste concrete and recycled concrete according to the present invention are a manufacturing method and manufacturing apparatus that absorb and fix carbon dioxide when treating waste concrete and recycled concrete, and granulate or make recycled aggregate.

Examples

[0027] <Manufacturing Method of Carbonated Granular Aggregate> Figure 1 is a flowchart showing the manufacturing method of carbonated granular aggregate of waste concrete and recycled concrete in Example 1 of the present invention. Figure 2 is an image showing an example of the granulated aggregate manufactured using the manufacturing method of carbonated granular aggregate of waste concrete and recycled concrete in Example 1 of the present invention. The manufacturing method of carbonated granular aggregate of waste concrete and recycled concrete in Example 1 is a manufacturing method that immobilizes carbon dioxide while maintaining its fluidity and shapes it into granules for waste concrete and recycled concrete. In this manufacturing method, first, waste concrete and recycled concrete generated at a construction site or the like are transported to a concrete manufacturing factory, a treatment factory, or the like. This is because there is no treatment equipment at the construction site. In a concrete manufacturing plant, a processing plant, or the like, in a manufacturing apparatus such as a closed container as shown after FIG. 7, waste concrete and returned concrete are introduced and brought into contact with carbon dioxide gas to fix carbon dioxide in the waste concrete and returned concrete (carbon dioxide fixation step). By using a closed container, carbon dioxide gas is sealed in, and the fixation of carbon dioxide to the waste concrete and returned concrete is promoted.

[0028] When fixing carbon dioxide to waste concrete and returned concrete in a closed container, when the waste concrete and returned concrete are brought into contact with carbon dioxide, an exothermic reaction occurs, and carbon dioxide is fixed and granulated (granulation step). The aggregate obtained by fixing carbon dioxide and granulating in this way has the properties shown in the photograph of FIG. 2. Thus, the fixation of carbon dioxide is completed.

[0029] At this time, as shown by Chemical Formula 1 in Chemical Formula 1, when calcium silicate compounds (tricalcium silicate: 3CaO·SiO2 and dicalcium silicate: 2CaO·SiO2), which are the main constituent compounds of Portland cement contained in waste concrete and returned concrete, come into contact with water and hydrate, calcium silicate hydrate and calcium hydroxide are produced. Here, when the produced calcium hydroxide is further brought into contact with carbon dioxide gas, as shown by Chemical Formula 2 in Chemical Formula 2, calcium hydroxide reacts with carbon dioxide to produce calcium carbonate, which is hardly soluble in water. Therefore, it becomes possible to fix carbon dioxide in the concrete.

[0030]

Chemical Formula

[0031]

Chemical Formula

[0032] The granulated aggregate obtained by fixing carbon dioxide by the method for producing carbonated granulated aggregate of waste concrete and returned concrete in Example 1 can be used, for example, as a raw material for fresh concrete. Or it can be used as a recycled roadbed material.

[0033] <Modification Example 1 of the Method for Producing Carbonated Granular Aggregate> The production methods of Modification Example 1 to Modification Example 3 are other production methods for increasing the fixed amount of carbon dioxide. Figure 4 is a flowchart showing Modification Example 1 of the method for producing carbonated granular aggregate of the remaining concrete and return concrete in Example 1. In Modification Example 1, first, a release agent is applied in a sealed container to prevent the remaining concrete and return concrete from sticking. The remaining concrete and return concrete are put into this sealed container, and water is added to the fluid remaining concrete and return concrete (water addition step). This is to increase the amount of calcium hydroxide generated. Then, carbon dioxide gas is sealed in the sealed container, and the carbon dioxide gas is brought into contact with the calcium hydroxide of the remaining concrete and return concrete (carbon dioxide immobilization step). In the production method of Modification Example 1, for example, by adding 60 kg / m 3 of water, the setting time of the concrete can be intentionally delayed to increase the dissolution amount of calcium hydroxide, and the fixed amount of carbon dioxide in the next step can be maximized. Here, "water addition" simply means adding water to the remaining concrete and return concrete.

[0034] As described above, as shown in Chemical Formula 1 of Chemical Formula 1, when the main constituent compounds of Portland cement contained in the remaining concrete and return concrete come into contact with water and hydrate, calcium silicate hydrate and calcium hydroxide are generated. When the generated calcium hydroxide is further brought into contact with carbon dioxide gas, as shown in Chemical Formula 2 of Chemical Formula 2, calcium hydroxide reacts with carbon dioxide to form calcium carbonate hardly soluble in water, and the amount of carbon dioxide fixed in the concrete can be increased. Note that in the production method of Modification Example 1, the granulation step is as described above.

[0035] <Modification Example 2 of the Method for Producing Carbonated Granular Aggregate> Figure 4 is a flowchart showing Modification Example 2 of the method for producing carbonated granular aggregate of the remaining concrete and return concrete in Example 1. The manufacturing method of Modification Example 2 is a method of intentionally delaying the condensation time of the remaining concrete and the return concrete in order to increase the fixed amount of carbon dioxide. Also in Modification Example 2, first, a release agent is applied in a sealed container to prevent the remaining concrete and the return concrete from sticking. Before enclosing carbon dioxide gas in this sealed container, the remaining concrete and the return concrete with fluidity are put into the sealed container, and a retarder is added to the sealed container to increase the production amount of calcium hydroxide (retarder addition step). Then, carbon dioxide gas is enclosed in the sealed container, and the carbon dioxide gas is brought into contact with the calcium hydroxide of the remaining concrete and the return concrete (carbon dioxide immobilization step). Even with the manufacturing method of Modification Example 2, the dissolution amount of calcium hydroxide can be increased to maximize the fixed amount of carbon dioxide in the next step.

[0036] The retarder added in the retarder addition step is a saccharide such as glucose that binds to calcium hydroxide to form a complex. Note that the retarder is not limited to glucose as long as it is a substance that has the effect of delaying the setting and hardening of concrete. A setting retarder for concrete mainly composed of lignin sulfonate, oxycarboxylate, silicofluoride, etc. can be used. Note that also in the manufacturing method of Modification Example 2, the granulation step is as described above.

[0037] <Modification Example 3 of the Manufacturing Method of Carbonated Granular Aggregate> Figure 5 is a flowchart showing Modification Example 3 of the manufacturing method of the carbonated granular aggregate of the remaining concrete and the return concrete in Example 1. The manufacturing method of Modification Example 3 is a manufacturing method that increases the fixed amount of carbon dioxide by adding water to the remaining and returned concrete and adding a retarder. Also in Modification Example 3, first, a release agent is applied inside the sealed container to prevent the remaining and returned concrete from sticking. Before enclosing carbon dioxide gas in this sealed container, fluid remaining and returned concrete is put into the sealed container, and water and a retarder are added thereto to increase the amount of calcium hydroxide generated. Then, carbon dioxide gas is enclosed in the sealed container, and the carbon dioxide gas is brought into contact with the calcium hydroxide of the remaining and returned concrete (carbon dioxide immobilization step). Also in the manufacturing method of Modification Example 3, the dissolved amount of calcium hydroxide can be increased to maximize the fixed amount of carbon dioxide in the next step.

Example

[0038] <Method for Manufacturing Carbonated Recycled Aggregate> FIG. 6 is a flowchart showing the method for manufacturing carbonated recycled aggregate of the remaining and returned concrete in Example 2 of the present invention. The manufacturing method of the carbonated recycled aggregate in Example 2 is a manufacturing method for immobilizing carbon dioxide on the remaining and returned concrete after solidifying and crushing it. As shown in the flowchart of FIG. 6, the remaining and returned concrete generated at the construction site is transported to a concrete manufacturing factory, a treatment factory, etc. for treatment.

[0039] First, the remaining and returned concrete is solidified (solidification step). Next, the solidified remaining and returned concrete is crushed (crushing step). This is to adjust the size and make it easier to use as recycled aggregate. Incidentally, if necessary, a large cutting step of cutting the lump of the remaining and returned concrete into larger pieces may be included before the crushing step. This is to make it easier to crush.

[0040] Next, using a manufacturing apparatus such as a sealed container as described later, residual concrete and returned concrete are introduced into it and brought into contact with carbon dioxide gas, and carbon dioxide is fixed to the residual concrete and returned concrete (carbon dioxide fixation step). In the manufacturing method of Example 2, since the carbon dioxide fixation reaction does not proceed if there is too little moisture, water is sprayed onto the crushed residual concrete and returned concrete (water spraying step). By spraying water, the reactivity between the residual concrete and returned concrete and carbon dioxide gas is also increased, and the efficiency of fixation is also enhanced. Note that the water spraying step may be performed inside the sealed container or before being introduced into the sealed container.

[0041] The recycled aggregate in which the fixation of carbon dioxide to the residual concrete and returned concrete is completed can be used as a raw material for fresh concrete. Or, it can be used as a recycled roadbed material.

[0042] <Configuration of Carbonated Granular Aggregate and Carbonated Recycled Aggregate Manufacturing Apparatus> The manufacturing apparatus for carbonated granular aggregate and carbonated recycled aggregate is an apparatus that can be used in any case of a process of introducing the residual concrete and returned concrete while maintaining its fluidity based on the manufacturing method of the carbonated granular aggregate of Example 1 described above, carbonating it while granulating, and a process of carbonating and making it into recycled aggregate after going through a solidification step and a crushing step based on the manufacturing method of the carbonated recycled aggregate of Example 2.

[0043] FIG. 7 is a front view showing a manufacturing apparatus for carbonated granular aggregate and carbonated recycled aggregate that fixes carbon dioxide to the residual concrete and returned concrete of the present invention. FIG. 8 is a cross-sectional view showing a rotating drum. FIG. 9 shows a lid for charging and discharging, (a) is a front view, and (b) is a side view. The manufacturing apparatus 1 for carbonated granular aggregate and carbonated recycled aggregate of the present invention is an apparatus including a cylindrical rotating drum 3 having mixing blades 2 formed spirally on the inner surface, and a rotational drive device 4 for rotating the rotating drum 3. Residual concrete and returned concrete or recycled aggregate are introduced into this rotating drum 3, carbon dioxide gas is sealed, and carbon dioxide is fixed while rotating the rotating drum 3.

[0044] The rotating drum 3 is a cylindrical barrel. The bottom surface side of the first truncated frustum-shaped barrel 5 is connected to one end of this rotating drum 3. An input / output port 6 is opened in this first truncated frustum-shaped barrel 5. Here, the reason for describing as the first and the second is not for grading or order, but for distinguishing members of the same form.

[0045] An input / output lid 7 is attached to the input / output port 6. The reason for making the truncated frustum shapes of the truncated frustum-shaped barrels 5 and 8 connected to both ends of the rotating drum 3 is that when the rotating drum 3 rotates and the remaining concrete and return concrete aggregates are rotated and stirred, at both ends of the rotating drum 3, the remaining concrete and return concrete aggregates flow complexly, for the purpose of stirring. Also, it is to prevent the remaining concrete and return concrete aggregates from contacting the input / output lid 7. However, both ends of the rotating drum 3 are not limited to the truncated frustum shape such as the first truncated frustum-shaped barrel 5 and the second truncated frustum-shaped barrel 8 in the illustrated example. As long as it is a container that can be rotated, instead of these truncated frustum-shaped barrels 5 and 8, it is also possible to be composed of plate members such as a simple disc shape or a curved surface shape.

[0046] The connection method of the truncated frustum-shaped barrels 5 and 8 to the rotating drum 3 may be, for example, a method of fixing by welding or bolting. When cleaning the inside of the rotating drum 3 and when replacing the mixing blade 2 described later, the bolting method that makes it easier to perform each operation by removing the truncated frustum-shaped barrels 5 and 8 from the rotating drum 3 is preferable.

[0047] The bottom surface side of the second truncated frustum-shaped barrel 8 with the same configuration is connected to the other end of the rotating drum 3. Further, a rotation drive device 4 is connected to this second truncated frustum-shaped barrel 8. This rotation drive device 4 is a device for rotating the rotating drum 3, and for example, a motor-driven hydraulic unit method or a motor gear drive method using gears is used. Note that the rotating means of the rotating drum 3 is not limited to the configuration of connecting the rotary drive device 4 in the illustrated example to the second frustum-shaped cylinder 8. For example, a configuration in which teeth of a gear serving as a driven mechanism are formed around the circumference of the rotating drum 3 and a pinion serving as a driving mechanism for driving these teeth of the gear is attached to the rotary drive device 4 may also be used (not shown). Furthermore, various means such as chain drive or belt drive can be employed.

[0048] The rotating drum 3 rotates within a ring-shaped drum pressing base 9 via rollers provided around it. The drum pressing base 9 is attached onto the base 10. In the illustrated example, the drum pressing base 9 is provided at three locations, but it is not limited to these three locations. Note that as long as the rotating drum 3 is configured to rotate, it is not limited to the configuration of the drum pressing base 9 type, and other configurations can be used.

[0049] The rotating drum 3 in the illustrated example has a cylindrical length of about 4 to 5 m and a cylindrical radius of about 1 m. Both frustum-shaped cylinders 5 and 8 are stirring devices having a length of about 1.5 m and a radius of the input / output port 6 of about 0.25 m. The total volume is about 20 to 25 m 3 However, in order to increase the opportunity for the crushed remaining concrete and returned concrete aggregate to come into contact with carbon dioxide gas while rotating below the position of the input / output port 6, in this rotating drum 3 of this capacity, the processing amount of the remaining concrete and returned concrete per time is preferably about 5 m 3 . Note that the dimensions of the rotating drum 3 in the illustrated example are just an example and are not limited to this size. Of course, it is possible to make the rotating drum 3 larger than this so that a large amount can be processed. Also, it is possible to use the drum of an agitator truck.

[0050] On the inner surface of the rotating drum 3, a mixing blade 2 is formed in a spiral shape. This mixing blade 2 has the function of stirring the input waste concrete and return concrete according to the rotation of the rotating drum 3. During this stirring, the contact with carbon dioxide gas is increased, and the carbon dioxide gas is immobilized on the waste concrete and return concrete. At the same time, it has the function of gradually shaping the waste concrete and return concrete hitting the mixing blade 2 into a granular shape. The mixing blade 2 is fixed to the rotating drum 3 and the frustum-shaped cylinders 5 and 8 by welding or bolting. When using the bolting method, it is suitable because the mixing blade 2 can be easily replaced when it wears out.

[0051] The rotating drum 3 is rotated by a rotation drive device 4 in both forward and reverse rotation directions. For example, when the rotating drum 3 is rotated forward, the mixing blade 2 acts so that the waste concrete and return concrete aggregate move inward from the input / output lid 7. When rotated in reverse, the mixing blade 2 moves the granular aggregate and recycled aggregate derived from the waste concrete and return concrete in the rotating drum 3 toward the input / output lid 7 side.

[0052] As shown in Fig. 9(a), in the input / output lid 7, a carbon dioxide gas injection port 11 penetrating into the rotating drum 3 is opened near its center. Carbon dioxide gas is injected into the rotating drum 3 into which the waste concrete and return concrete aggregate are input from this injection port 11.

[0053] As shown in Fig. 9(b), an input / output lid 7 is detachably attached to the input / output port 6. The input / output lid 7 is attached with a sealing material 12 having airtightness and liquid tightness at the periphery of the disc-shaped lid body so as to be in close contact with the input / output port 6 of the rotating drum 3. This is to optimize the concentration of the carbon dioxide gas sealed in the rotating drum 3 and improve the immobilization rate.

[0054] It is preferable to provide a concentration meter for measuring the concentration of carbon dioxide gas in the rotary drum 3 on the charging / discharging lid 7. Further, it is preferable to provide a pressure reducing adjustment pipe for adjusting the air pressure of carbon dioxide gas in the rotary drum 3 on the charging / discharging lid 7. This is to optimize the concentration of carbon dioxide gas enclosed in the rotary drum 3 and improve the immobilization rate.

[0055] <Example of use of carbonated granular aggregate and carbonated recycled aggregate production apparatus 1> When the carbonated granular aggregate and carbonated recycled aggregate production apparatus 1 of the present invention is used in the production method of the carbonated granular aggregate of Example 1, the residual concrete and return concrete are charged into the rotary drum 3 while maintaining fluidity and granulated while carbonating. First, open the charging / discharging lid 7 of the rotary drum 3, charge the residual concrete and return concrete, and close the charging / discharging lid 7. After sucking the internal air from the injection port 11 of the charging / discharging lid 7, carbon dioxide gas is injected. Next, rotate the rotary drum 3 with the rotation drive device 4. At this time, while carbon dioxide contacts the residual concrete and return concrete aggregate and causes an exothermic reaction, a mortar layer forms around the residual concrete and return concrete aggregate as a core, and the residual concrete and return concrete aggregate granulates. When a predetermined time has elapsed, carbon dioxide is immobilized in the granulated aggregate derived from the residual concrete and return concrete. Then, rotate the rotary drum 3 in the reverse direction with the rotation drive device 4, and move the carbonated granular aggregate derived from the residual concrete and return concrete to the charging / discharging lid 7 side. Open the charging / discharging lid 7 and take it out to complete the immobilization process.

[0056] <Example of use of carbonated granular / recycled aggregate production apparatus 2> When the carbonated granular aggregate and carbonated recycled aggregate production apparatus 1 of the present invention is used in the production method of the carbonated recycled aggregate of Example 2, after the residual concrete and return concrete have undergone the solidification / crushing process, they are carbonated with the recycled aggregate. First, open the charging / discharging lid 7 of the rotary drum 3, charge the recycled aggregate derived from the residual concrete and return concrete crushed to a predetermined size, and close the charging / discharging lid 7. After sucking the internal air from the injection port 11 of the charging / discharging lid 7, carbon dioxide gas is injected. Next, the rotary drum 3 is rotationally driven by the rotation driving device 4. When a predetermined time has elapsed, carbon dioxide is immobilized in the recycled aggregate. Then, the rotary drum 3 is reversely rotated by the rotation driving device 4 to move the recycled aggregate toward the charging / discharging lid 7 side. The charging / discharging lid 7 is opened and the material is taken out, completing the immobilization process.

[0057] <Configuration of a Modified Example of the Carbonated Granular Aggregate and Carbonated Recycled Aggregate Manufacturing Apparatus> FIG. 10 is a front view showing a modified example of the carbonated granular aggregate and carbonated recycled aggregate manufacturing apparatus provided with an inclination driving device, where (a) is the state before inclination, (b) is the state where the charging / discharging port side of the rotary drum is raised, and (c) is the state where the rotation driving device side of the rotary drum is raised. The modified example of the carbonated granular aggregate and carbonated recycled aggregate manufacturing apparatus 1 shown in FIG. 10 is provided with an inclination driving device 13 for inclining the rotary drum 3. The basic configuration of the carbonated granular aggregate and carbonated recycled aggregate manufacturing apparatus 1 is the same as the above-described configuration of Example 2. In this modified example, the carbonated granular aggregate and carbonated recycled aggregate manufacturing apparatus 1 is fixed to the base 10, and two sets of inclination driving devices 13 are attached to this base 10 to incline the rotary drum 3 so that its charging / discharging port 6 rises, or to incline it so that the rotation driving device 4 side rises. Each inclination driving device 13 is provided on the charging / discharging port 6 side and the rotation driving device 4 side. The inclination driving device 13 may be hydraulically driven or electrically driven. In this way, by inclining the rotary drum 3, it becomes easier to charge the remaining concrete, returned concrete, water, and additives, and it becomes easier to take out the remaining concrete and returned concrete aggregates after the treatment.

[0058] Note that the present invention is not limited to the above-described embodiments of the invention as long as it is configured to immobilize carbon dioxide by making the remaining concrete and returned concrete, which were conventionally treated and discarded, absorb and fix carbon dioxide and making them into granular aggregates or recycled aggregates so as to be easily reused, and can be variously modified without departing from the gist of the present invention.

Industrial Applicability

[0059] The method for manufacturing carbonated granular aggregate and carbonated recycled aggregate from residual concrete and returned concrete of the present invention can be applied not only to residual concrete or returned concrete but also to demolished concrete generated by demolishing buildings.

Explanation of Signs

[0060] 1 Manufacturing apparatus for carbonated granular aggregate and carbonated recycled aggregate 2 Mixing blade 3 Rotary drum 4 Rotation drive device 5 First frustum-shaped cylinder 6 Feed-in / discharge port 7 Feed-in / discharge lid 8 Second frustum-shaped cylinder 9 Drum pressing base 10 Base 11 Injection port 12 Sealing material 13 Tilt drive device

Claims

1. A method for producing carbonated granular aggregate of waste concrete and recycled concrete by immobilizing carbon dioxide in waste concrete and recycled concrete, comprising: A carbon dioxide immobilization step of introducing and bringing into contact fluid waste concrete and recycled concrete and carbon dioxide gas in a sealed container to immobilize carbon dioxide in the waste concrete and recycled concrete; and A granulation step of shaping the waste concrete and recycled concrete into granules in the sealed container, and using the carbonated granular aggregate obtained by immobilizing carbon dioxide as a raw material for fresh concrete. A method for producing carbonated granular aggregate of waste concrete and recycled concrete, characterized in that.

2. A method for producing carbonated granular aggregate of waste concrete and recycled concrete by immobilizing carbon dioxide in waste concrete and recycled concrete, comprising: A water addition step of introducing fluid waste concrete and recycled concrete into a sealed container and adding water thereto; A carbon dioxide immobilization step of enclosing carbon dioxide gas in the sealed container after the treatment of the water addition step, bringing the carbon dioxide gas into contact with the waste concrete and recycled concrete, and immobilizing carbon dioxide in the waste concrete and recycled concrete; and A granulation step of shaping the waste concrete and recycled concrete into granules in the sealed container, and using the carbonated granular aggregate obtained by immobilizing carbon dioxide as a raw material for fresh concrete. A method for producing carbonated granular aggregate of waste concrete and recycled concrete, characterized in that.

3. A method for producing carbonated granular aggregate of waste concrete and recycled concrete by immobilizing carbon dioxide in waste concrete and recycled concrete, comprising: A retarder addition step of introducing fluid waste concrete and recycled concrete into a sealed container and adding a retarder thereto; A carbon dioxide immobilization step of enclosing carbon dioxide gas in the sealed container after the treatment of the retarder addition step, bringing the carbon dioxide gas into contact with the waste concrete and recycled concrete, and immobilizing carbon dioxide in the waste concrete and recycled concrete; and A granulation step of shaping the waste concrete and recycled concrete into granules in the sealed container, and using the carbonated granular aggregate obtained by immobilizing carbon dioxide as a raw material for fresh concrete. A method for producing carbonated granular aggregate of waste concrete and recycled concrete, characterized in that.

4. A method for producing carbonated granular aggregate of waste concrete and recycled concrete by immobilizing carbon dioxide in waste concrete and recycled concrete, comprising: A water addition and retarder addition step of introducing fluid waste concrete and recycled concrete into a sealed container and adding water and a retarder thereto; In the sealed container, after the treatment in the water addition / delay agent addition step, a carbon dioxide gas is sealed, the remaining concrete and the return concrete are brought into contact with the carbon dioxide gas, and a carbon dioxide immobilization step of immobilizing carbon dioxide on the remaining concrete and the return concrete is performed. In the sealed container, it consists of a granulation step of shaping the remaining concrete and the return concrete into granules. A method for producing carbonated granular aggregate of remaining concrete and return concrete, characterized in that the carbonated granular aggregate obtained by immobilizing carbon dioxide is used as a raw material for fresh concrete.

5. The retarder added in the water addition / delay agent addition step is a setting retarder for concrete mainly composed of saccharides such as glucose, lignin sulfonic acid, oxycarboxylic acid, and silicofluoride. The method for producing carbonated granular aggregate of remaining concrete and return concrete according to claim 3 or 4, characterized by this.

6. A method for producing carbonated recycled aggregate of remaining concrete and return concrete, which immobilizes carbon dioxide on the remaining concrete and the return concrete. A crushing step of crushing the remaining concrete and the return concrete into a predetermined size. A carbon dioxide immobilization step of charging and bringing the crushed remaining concrete and return concrete into contact with carbon dioxide gas in a sealed container to immobilize carbon dioxide on the remaining concrete and the return concrete. It consists of this. A method for producing carbonated recycled aggregate of remaining concrete and return concrete, characterized in that the carbonated recycled aggregate obtained by immobilizing carbon dioxide is used as a raw material for fresh concrete or a recycled roadbed material.

7. The method for producing carbonated recycled aggregate of remaining concrete and return concrete according to claim 6, characterized by having a solidification step of solidifying the remaining concrete and the return concrete before the crushing step.

8. The method for producing carbonated recycled aggregate of remaining concrete and return concrete according to claim 6, characterized by having a watering step of wetting with water after the crushing step to promote carbon dioxide immobilization of the remaining concrete and the return concrete.

9. A production apparatus for carbonated granular aggregate and carbonated recycled aggregate that immobilizes carbon dioxide on remaining concrete and return concrete. An input / discharge port (6), a cylindrical rotary drum (3) provided with a driven mechanism of a rotary drive device (4). It includes a mixing blade (2) formed on the inner surface of the rotary drum (3). A production apparatus for carbonated granular aggregate and carbonated recycled aggregate of remaining concrete and return concrete, characterized in that the remaining concrete and return concrete and carbon dioxide gas are charged into the rotary drum (3), and while rotating the rotary drum (3), it is configured to immobilize carbon dioxide on the remaining concrete and return concrete.

10. An apparatus for manufacturing carbonated granular aggregate and carbonated recycled aggregate for immobilizing carbon dioxide in waste concrete and returned concrete, a first truncated conical cylinder body (5) having an inlet / outlet (6) provided on the truncated side, and a second truncated conical cylinder body (8) having a rotary drive device (4) connected to the truncated side, each having a cylindrical rotary drum (3) connected to each bottom surface of the cylinder body, a mixing blade (2) spirally formed on the inner surface of the rotary drum (3), and an inlet / outlet lid (7) that is attached to the inlet / outlet (6) so as to be freely opened and closed and that enhances the airtightness inside the rotary drum (3). The apparatus for manufacturing carbonated granular aggregate and carbonated recycled aggregate for waste concrete and returned concrete is configured such that crushed waste concrete and returned concrete and carbon dioxide gas are introduced into the rotary drum (3) from the inlet / outlet lid (7), the rotary drum (3) is rotated, and the waste concrete and returned concrete are granulated while immobilizing carbon dioxide in the waste concrete and returned concrete.

11. The rotary drum (3) further includes an inclination drive device (13), and is configured to incline the rotary drum (3) when discharging waste concrete and returned concrete in which carbon dioxide has been immobilized. The apparatus for manufacturing carbonated granular aggregate and carbonated recycled aggregate for waste concrete and returned concrete according to claim 10.

Images