WO2021193571A1 - Treatment method for incinerator fly ash - Google Patents

Treatment method for incinerator fly ash Download PDF

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Publication number
WO2021193571A1
WO2021193571A1 PCT/JP2021/011802 JP2021011802W WO2021193571A1 WO 2021193571 A1 WO2021193571 A1 WO 2021193571A1 JP 2021011802 W JP2021011802 W JP 2021011802W WO 2021193571 A1 WO2021193571 A1 WO 2021193571A1
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Prior art keywords
ash
incinerator
fly ash
particle size
additive
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PCT/JP2021/011802
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French (fr)
Japanese (ja)
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恒河 繁泉
久保田　洋
春菜 ▲高▼地
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株式会社フジタ
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Priority to JP2022510507A priority Critical patent/JP7457793B2/en
Publication of WO2021193571A1 publication Critical patent/WO2021193571A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B1/00—Dumping solid waste
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless

Definitions

  • the present invention relates to a method for treating incinerated fly ash.
  • Incinerator fly ash is generated by incineration of waste in the incinerator. Incinerator fly ash contains heavy metals. Therefore, the incinerated fly ash is subjected to an intermediate treatment to prevent the elution of heavy metals, and then landfilled at the final disposal site.
  • Patent Document 1 describes a method for making heavy metals contained in waste sparingly soluble. In Patent Document 1, heavy metals are aggregated using a chelating agent.
  • a surplus chelating agent is used to ensure that the heavy metal is sparingly soluble. Elutes and becomes a load of organic matter.
  • the excess chelating agent inhibits the nitrification reaction in the nitrification step of water treatment of leachate generated from waste. For these reasons, the load of water treatment of leachate generated from waste may increase at the final disposal site.
  • the present disclosure has been made in view of the above problems, and provides a method for treating incinerated fly ash, which can suppress the elution of heavy metals contained in incinerated fly ash and can suppress the elution of organic substances derived from a chelating agent. With the goal.
  • the method for treating incinerated fly ash includes a kneading step of kneading an additive containing at least one of a silicon compound and an aluminum compound and incinerated fly ash to prepare a mixture.
  • the mixture is provided with a carbonation step of subjecting the mixture to a carbonation treatment.
  • the additive is incinerator main ash.
  • the additive is an aqueous sodium silicate solution, crushed concrete, a calcium compound or melt contained in cement, or rock or debris containing silica mineral.
  • a separation step of separating the incinerated main ash into a large particle size ash and a small particle size ash having a smaller maximum particle size than the large particle size ash is provided, and the additive is the above-mentioned additive.
  • Small particle size ash is the above-mentioned additive.
  • a separation step of washing the incinerated main ash with water to separate it into a large particle size ash and a small particle size ash having a smaller maximum particle size than the large particle size ash is provided.
  • the additive is the small particle size ash.
  • a cleaning step of cleaning the incinerated main ash with water is provided, and the additive is the cleaning wastewater used for cleaning the incinerated main ash in the cleaning step.
  • a pre-carbonation step of performing a carbonization treatment on the incinerated main ash and a washing step of washing the incinerated main ash carbonized in the pre-carbonation step with water is the cleaning wastewater used for cleaning the incineration main ash in the cleaning step.
  • a preferred embodiment of the method for treating incinerated flying ash includes a washing step of washing a mineral containing at least one of a silicon compound and an aluminum compound with water, and the additive is used for washing the mineral in the washing step. It is drainage.
  • the elution of heavy metals contained in the incinerated fly ash can be suppressed and the elution of organic substances derived from the chelating agent can be suppressed.
  • FIG. 1 is a flowchart showing a method for treating incinerated fly ash according to the first embodiment.
  • FIG. 2 is a graph showing the experimental results regarding the concentration of lead eluted from incinerated fly ash.
  • FIG. 3 is a diagram showing components contained in the incinerator main ash and the incinerator fly ash.
  • FIG. 4 is a graph showing the experimental results regarding the concentration of lead eluted from incinerated fly ash.
  • FIG. 5 is a flowchart showing a method for treating incinerated fly ash according to the second embodiment.
  • FIG. 6 is a flowchart showing a method for treating incinerated fly ash according to the third embodiment.
  • FIG. 7 is a flowchart showing a method for treating incinerated fly ash according to a modified example of the third embodiment.
  • FIG. 8 is a graph showing the experimental results regarding the concentration of aluminum eluted from the incinerator main ash.
  • the present invention will be described in detail with reference to the drawings.
  • the present invention is not limited to the embodiment for carrying out the present invention (hereinafter referred to as the embodiment).
  • the components in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, that is, those in a so-called equal range. Further, the components disclosed in the following embodiments can be appropriately combined.
  • FIG. 1 is a flowchart showing a method for treating incinerated fly ash according to the first embodiment.
  • the incinerator ash discharged from the incinerator is divided into incinerator ash and incinerator fly ash.
  • Incinerator fly ash contains heavy metals such as lead (Pb). Since the heavy metals contained in the incinerator fly ash are easily eluted, the incinerator fly ash is treated so that the heavy metals do not elute before being landfilled.
  • the method for treating incinerated fly ash of the first embodiment is a method for suppressing the elution of heavy metals from the incinerated fly ash discharged from the incinerator.
  • the method for treating incinerated fly ash of the first embodiment includes a kneading step S11 and a carbonation step S12.
  • the kneading step S11 is a step of kneading the additive containing at least one of the silicon compound (Si compound) and the aluminum compound (Al compound) with the incinerated fly ash.
  • the silicon compound include silicon dioxide (SiO 2 ).
  • the aluminum compound include polyaluminum chloride (PAC) and aluminum oxide (Al 2 O 3 ).
  • kneading step S11 for example, 213 kg of silicon dioxide and 505 kg of water are added to 2 tons of incinerated fly ash by dry weight and kneaded. Further, in the kneading step S11, for example, 457 kg of aluminum oxide is added to incinerated fly ash having a dry weight of 2 tons and kneaded.
  • the carbonation step S12 is a step of subjecting the mixture prepared in the kneading step S11 to a carbonation treatment.
  • the carbonation treatment is a treatment in which the mixture is exposed to carbon dioxide gas (carbon dioxide (CO 2 ) gas).
  • the mixture is arranged in a container (carbonation treatment tank).
  • the container is, for example, a substantially rectangular parallelepiped container.
  • the container is provided with a partition wall that vertically divides the internal space.
  • the partition wall is a plate-shaped member parallel to the bottom surface of the container and includes a plurality of vents.
  • the mixture is placed on the bulkhead. Carbon dioxide is introduced into the space below the bulkhead with the mixture resting on the bulkhead. Carbon dioxide contacts the mixture through the vents in the bulkhead.
  • the mixture is carbonated by absorbing carbon dioxide.
  • the carbonation step S12 for example, a container having a capacity of 8 m 3 is used as a container.
  • the mixture prepared in the kneading step S11 is uniformly placed in the container to a thickness of about 30 cm or more and 50 cm or less. Then, 60 g of carbon dioxide gas per 1 kg of the mixture is aerated from the lower part of the partition wall of the container for 6 hours.
  • at least one of the cement-based hydration product and sodium silicate can be carbonated.
  • a curing step of 3 hours or more and 48 hours or less, or 6 hours or more and 24 hours or less may be performed.
  • a hydration reaction of a calcium compound contained in cement which is an example of an additive, occurs.
  • an alkali-silica reaction occurs in which the alkaline component in the incinerator fly ash reacts with silica as an additive. This makes it possible to produce sodium silicate.
  • the cement-based hydration product and sodium silicate are carbonated to produce minerals. The mineral can occlude or adsorb heavy metals.
  • the hydration reaction and the pozzolan reaction proceed.
  • the pozzolan reaction calcium hydroxide, which is a cement-based hydration reaction product, reacts with silicon dioxide and aluminum oxide contained in the additive. As a result, the pH of the kneaded product is lowered, and the solubility of heavy metals contained in the incinerated fly ash in the kneaded product can be reduced.
  • FIG. 2 is a graph showing the results of the first experiment regarding the concentration of lead eluted from incinerated fly ash.
  • the first comparative example is incinerated fly ash that has not been treated at all.
  • the second comparative example is incinerated fly ash that has been subjected to carbonation only.
  • the third comparative example is a mixture of silicon dioxide and incinerated fly ash. In the third comparative example, 53.2 g of silicon dioxide was added to 1 kg of incinerated fly ash. The third comparative example is not carbonated.
  • the fourth comparative example is a mixture of polyaluminum chloride and incinerated fly ash. In the fourth comparative example, 114.2 g of polyaluminum chloride was added to 1 kg of incinerated fly ash. The fourth comparative example is not carbonated.
  • the first embodiment is a carbonated mixture of silicon dioxide and incinerator fly ash. That is, the first embodiment is the incinerator fly ash treated by the method for treating the incinerator fly ash of the first embodiment described above. In the first embodiment, 53.2 g of silicon dioxide was added to 1 kg of incinerated fly ash in the kneading step S11.
  • the second embodiment is a carbonated mixture of polyaluminum chloride and incinerated fly ash. That is, the second embodiment is the incinerator fly ash treated by the method for treating the incinerator fly ash of the first embodiment described above. In the second embodiment, 114.2 g of polyaluminum chloride was added to 1 kg of incinerated fly ash in the kneading step S11.
  • carbon dioxide gas is aerated after the water content is adjusted so that the water content of the incinerated fly ash (or mixture) is 20%. Made by. More specifically, the carbonation treatment was carried out for 1.8 hours. The amount of carbon dioxide aerated in 1.8 hours was 60 g per 1 kg of incinerated fly ash (or mixture).
  • the concentration of lead eluted from the first example and the second embodiment is very small with respect to the concentration of lead eluted from the first comparative example. In the following description, the reduction rate will be used.
  • the reduction rate is a value obtained by expressing the ratio of the difference between the measurement result of each sample and the measurement result of the first comparative example to the measurement result (concentration of eluted lead) of the first comparative example as a percentage. That is, assuming that the reduction rate is R, the measurement result of the first comparative example is S 1 , and the measurement result of other samples is S x , the reduction rate is expressed by the following equation (1).
  • the reduction rate of the second comparative example remains at about 32%.
  • the reduction rate of the third comparative example remains at about 16%.
  • the reduction rate of the fourth comparative example remains at about 24%.
  • the reduction rate of the first embodiment is about 99.5%.
  • the reduction rate of the second embodiment is about 99.4%.
  • the method for treating the incinerated fly ash of the first embodiment includes a kneading step S11 and a carbonation step S12.
  • the kneading step S11 is a step of kneading an additive containing at least one of a silicon compound and an aluminum compound with incinerated fly ash to prepare a mixture.
  • the carbonation step S12 is a step of subjecting the mixture to a carbonation treatment.
  • the elution of the heavy metal is suppressed due to the insolubilization of the heavy metal in the carbonation step S12 and the reason that the heavy metal is occluded or adsorbed to another substance.
  • elution of heavy metals can be suppressed without using a chelating agent. Therefore, the method for treating incinerated fly ash of the first embodiment can suppress the elution of heavy metals contained in the incinerated fly ash, and can suppress the elution of organic substances derived from the chelating agent by not using the chelating agent.
  • incinerator main ash is used as an additive in the kneading step S11. That is, in the kneading step S11, the incinerator main ash as an additive and the incinerator fly ash are kneaded. In the kneading step S11 of the modified example of the first embodiment, for example, 1 ton of incinerator fly ash by dry weight is added to 1 ton of incinerator fly ash by dry weight and kneaded. Then, in the carbonation step S12, the carbonation treatment is performed on the mixture of the incinerator main ash and the incinerator fly ash produced in the kneading step S11.
  • FIG. 3 is a diagram showing components contained in the incinerator main ash and the incinerator fly ash.
  • FIG. 3 shows the results of analysis of the components contained in the incinerator main ash and the incinerator fly ash using the scattered radiation FP method.
  • FIG. 3 shows the mass percent concentration of the substance contained in each of the incinerator main ash and the incinerator fly ash. Balance in FIG. 3 indicates a substance that was not measured by the scattered radiation FP method.
  • the amount of silicon dioxide (SiO 2 ) contained in the incinerator main ash is about 10 times that of silicon dioxide contained in the incinerator fly ash.
  • the amount of aluminum oxide (Al 2 O 3 ) contained in the incineration main ash is about 40 times that of the aluminum oxide contained in the incineration fly ash. Therefore, by using the incinerator main ash as an additive, it is possible to supply the silicon compound and the aluminum compound to the incinerator fly ash.
  • the amount of iron oxide (Fe 2 O 3 ) contained in the incinerated main ash is about 8.5 times that of iron oxide contained in the incinerated flying ash. Iron oxide (Fe 2 O 3 ), which is abundant in incinerator ash, adsorbs heavy metals. Therefore, the incinerator main ash contributes to the suppression of elution of heavy metals.
  • FIG. 2 is a graph showing the results of the second experiment regarding the concentration of lead eluted from incinerated fly ash.
  • the fifth comparative example is incinerated fly ash that has not been treated at all.
  • the sixth comparative example is incinerated fly ash that has been subjected to carbonation only.
  • the seventh comparative example is a mixture of incinerator main ash and incinerator fly ash. In the seventh comparative example, the same amount of incinerator main ash was added to the incinerator fly ash.
  • a seventh comparative example is a non-carbonated mixture.
  • the third embodiment is a carbonated mixture of incinerator main ash and incinerator fly ash. That is, the third embodiment is the incinerator fly ash treated by the method for treating the incinerator fly ash of the modified example of the first embodiment. In the third embodiment, in the kneading step S11, the same amount of incinerator main ash as the incinerator fly ash was added.
  • the carbonation treatment of the 6th Comparative Example and the 3rd Example was carried out by aerating carbon dioxide gas after adjusting the water content so that the water content of the incinerated fly ash (or mixture) was 20%. More specifically, the carbonation treatment was carried out for 1.8 hours. The amount of carbon dioxide aerated in 1.8 hours was 60 g per 1 kg of incinerated fly ash (or mixture).
  • the concentration of lead eluted from the third example is very small with respect to the concentration of lead eluted from the fifth comparative example.
  • the reduction rate of the sixth comparative example remains at about 81%.
  • the reduction rate of the seventh comparative example remains at about 60%.
  • the reduction rate of the third embodiment is about 99.7%.
  • the additive is the incinerator main ash.
  • the main ash to be incinerated contains a large amount of silicon compounds and aluminum compounds, it is possible to easily supply the silicon compounds and aluminum compounds to the incinerated fly ash in the kneading step S11. Since the incinerator main ash is produced together with the incinerated fly ash in the incinerator, it can be easily procured. Therefore, the cost spent on the additive can be reduced as compared with the case where the silicon compound or the aluminum compound is used as the additive. In addition, iron oxide contained in the incinerator main ash further suppresses the elution of heavy metals. Therefore, according to the method for treating incinerator fly ash of the modified example of the first embodiment, the incinerator fly ash can be treated more easily.
  • the large particle size ash is a lumpy ash (clinker), slag, or the like.
  • the small particle size ash is an ash having a particle size of 5 mm or less. Since the small particle size ash has a larger specific surface area than the large particle size ash, the elution amount of the silicon compound and the aluminum compound can be increased during kneading with the incinerated fly ash.
  • FIG. 5 is a flowchart showing a method for treating incinerated fly ash according to the second embodiment.
  • the method for treating incinerated fly ash of the second embodiment includes a separation step S21, a kneading step S22, and a carbonation step S23.
  • Separation step S21 is a step of separating the incinerator main ash into large particle size ash and small particle size ash.
  • the maximum particle size of the small particle size ash is smaller than the minimum particle size of the large particle size ash.
  • the small particle size ash is the group with the smallest maximum particle size among the two divided groups of the incinerator main ash.
  • the particle size of the small particle size ash is 5 mm or less. More specifically, the incinerator main ash that passes through a mesh having a mesh opening of 5 mm is a small particle size ash.
  • the incinerator main ash that does not pass through the mesh with a mesh size of 5 mm is the large particle size ash.
  • the particle size of the small particle size ash does not necessarily have to be 5 mm or less, and is not particularly limited.
  • the incinerator main ash is separated into a large particle size ash and a small particle size ash by, for example, a sieve.
  • the incinerator main ash may be separated into a large particle size ash and a small particle size ash by washing with water.
  • the small particle size ash produced in the separation step S21 and the incinerator fly ash are kneaded. That is, in the kneading step S22, the small particle size ash as an additive and the incinerator fly ash are kneaded.
  • the carbonation step S23 is a step of subjecting the mixture prepared in the kneading step S22 to a carbonation treatment.
  • the method for treating the incinerated fly ash of the second embodiment includes a separation step S21 for separating the incinerated main ash into a large particle size ash and a small particle size ash having a smaller maximum particle size than the large particle size ash. ..
  • the additive in the kneading step S22 is a small particle size ash.
  • the small particle size ash which is a part of the main ash to be incinerated, has a large surface area and a large amount of elution of the silicon compound and the aluminum compound, it is possible to easily supply the silicon compound and the aluminum compound to the incinerated fly ash in the kneading step S22. It becomes. Further, the small particle size ash having a smaller particle size can be easily kneaded with the incinerator fly ash as compared with the case where the entire incinerator ash and the incinerator fly ash are kneaded. Moreover, since the incinerator main ash is produced together with the incinerated fly ash in the incinerator, it can be easily procured.
  • the cost spent on the additive can be reduced as compared with the case where the silicon compound or the aluminum compound is used as the additive.
  • the small particle size ash can elute more silicon compounds and aluminum compounds than the large particle size ash, it is added as compared with the case where both the small particle size ash and the large particle size ash are added. The amount of things can be reduced.
  • small particle size ash contains more heavy metals than large particle size ash. Since most of the heavy metals contained in the incinerator main ash are kneaded with the incinerator fly ash and hardly dissolved, the amount of heavy metals contained in the residual large particle size ash is reduced. Therefore, the incinerator main ash (large particle size ash) can be easily recycled.
  • the incinerator main ash (large particle size ash) is recycled, for example, as a raw material for cement or a civil engineering material.
  • the method for treating the incinerated fly ash of the second embodiment is to wash the incinerator main ash with water to obtain a large particle size ash and a small particle size ash having a smaller maximum particle size than the large particle size ash.
  • a separation step S21 for separating is provided.
  • the additive in the kneading step S22 is a small particle size ash.
  • the incinerator main ash can be easily separated into large particle size ash and small particle size ash.
  • FIG. 6 is a flowchart showing a method for treating incinerated fly ash according to the third embodiment.
  • the method for treating incinerated fly ash according to the third embodiment includes a cleaning step S32, a kneading step S33, and a carbonation step S34.
  • the cleaning step S32 is a step of cleaning the incinerator main ash with water.
  • the cleaning wastewater generated in the cleaning step S32 is water in contact with the incinerator main ash. By washing, the water-soluble silicon component and aluminum component can be eluted.
  • the carbonation step S34 is a step of subjecting the mixture prepared in the kneading step S33 to a carbonation treatment.
  • the method for treating incinerator fly ash according to the third embodiment includes a cleaning step S32 for cleaning the incinerator main ash with water.
  • the additive in the kneading step S33 is the washing wastewater used for washing the incinerator main ash in the washing step S32.
  • the washing wastewater that has passed through the incinerator main ash contains silicon and aluminum components, it is possible to easily supply the silicon / aluminum compound to the incinerator fly ash in the kneading step S33. Since the incinerator main ash is produced together with the incinerated fly ash in the incinerator, it can be easily procured. Therefore, the cost spent on the additive can be reduced as compared with the case where the silicon compound or the aluminum compound is used as the additive. In addition, the wash effluent contains more heavy metals than the wash residue.
  • the incinerator ash (cleaning residue) is recycled, for example, as a raw material for cement or a civil engineering material.
  • FIG. 7 is a flowchart showing a method for treating incinerated fly ash in a modified example of the third embodiment.
  • the method for treating the incinerated fly ash of the modified example of the third embodiment includes a pre-carbonation step S31, a cleaning step S32, a kneading step S33, and a carbonation step S34.
  • the pre-carbonation step S31 is a step of carbonating the incinerator main ash.
  • An experiment (hereinafter referred to as the third experiment) was conducted on the carbonated incinerator ash.
  • the concentration of eluted aluminum was measured with respect to the uncarbonated incinerator ash and the carbonated incinerator ash.
  • 10 times the amount of pure water was added to the sample, and then the sample was shaken for 6 hours. The sample was then separated into solid and liquid by a centrifuge. The separated solution was filtered through a membrane filter having a pore size of 1.0 ⁇ m. The concentration of aluminum (mg / L) in the filtered solution was measured.
  • FIG. 8 is a graph showing the experimental results regarding the concentration of aluminum eluted from the incinerator main ash. As shown in FIG. 8, the concentration of aluminum eluted from the carbonated incinerator ash is much higher than that of the uncarbonated incinerator ash.
  • the cleaning step S32 is a step of cleaning the incinerator ash carbonated in the pre-carbonation step S31 with water.
  • the washing wastewater generated in the washing step S32 is water in contact with the carbonated incinerator ash. Therefore, a large amount of aluminum is eluted in the washing wastewater.
  • the method for treating the incinerated fly ash of the modified example of the third embodiment is the pre-carbonation step S31 in which the incinerated main ash is carbonated and the incineration carbonated in the pre-carbonation step S31.
  • a cleaning step S32 for cleaning the main ash with water is provided.
  • the additive in the kneading step S33 is the washing wastewater used for washing the incinerator main ash in the washing step S32.
  • the washing wastewater that has passed through the carbonated incinerator main ash contains a large amount of aluminum, it is possible to easily supply the aluminum compound to the incinerator fly ash in the kneading step S33. Since the incinerator main ash is produced together with the incinerated fly ash in the incinerator, it can be easily procured. Therefore, the cost spent on the additive can be reduced as compared with the case where the silicon compound or the aluminum compound is used as the additive. In addition, the wash effluent contains more heavy metals than the wash residue.
  • the incinerator ash (cleaning residue) is recycled, for example, as a raw material for cement or a civil engineering material.
  • the mineral containing at least one of the silicon compound and the aluminum compound may be washed with water instead of the incinerator main ash.
  • Minerals include, for example, crushed concrete, calcium-based compounds (acrite, belite, aluminate phase, ferrite phase) or melts (slag) contained in cement, or rocks or debris containing silica minerals (igneous rock (quartz)). , Tridimite, Cristobalite, Coesite, Stishovite, etc.), Sedimentary rock (diatomaceous soil)), etc.
  • Minerals containing silica are preferable when washed with an alkaline solution because the solubility of silica increases.
  • the method for treating the incinerated fly ash includes a washing step S32 for washing a mineral containing at least one of a silicon compound and an aluminum compound with water. May be good.
  • the additive in the kneading step S33 is the washing wastewater used for washing the minerals in the washing step S32.
  • the washing wastewater that has passed through the mineral contains a silicon compound or an aluminum compound, it is possible to easily supply the silicon compound or the aluminum compound to the incinerated fly ash in the kneading step S33.
  • incinerator ash was used as an additive containing at least one of a silicon compound and an aluminum compound.
  • crushed concrete crushed concrete, calcium-based compounds (acrite, belite, aluminate phase, ferrite phase) or melts (slag) contained in cement, or rocks containing silica minerals or Debris (igneous rock (quartz, tridimite, cristobalite, coesite, stishovite, etc.), sedimentary rock (diatomaceous soil)) and the like can be used.
  • an aqueous sodium silicate solution water glass
  • water glass aqueous sodium silicate solution

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Abstract

Provided is a treatment method for incinerator fly ash, the method enabling suppression of elution of heavy metals contained in the incinerator fly ash and also enabling suppression of elution of chelating agent-derived organic matter. The treatment method for incinerator fly ash comprises: a kneading step S11 in which an additive containing a silicon compound and/or an aluminum compound is kneaded with incinerated fly ash to create a mixture; and a carbonation step S12 in which the mixture is subjected to a carbonation treatment.

Description

焼却飛灰の処理方法How to treat incinerated fly ash
　本発明は、焼却飛灰の処理方法に関する。 The present invention relates to a method for treating incinerated fly ash.
　焼却施設における廃棄物の焼却によって焼却飛灰が発生する。焼却飛灰は重金属を含有している。このため、焼却飛灰は、重金属の溶出を防止する中間処理を施された後、最終処分場で埋立て処分される。例えば、特許文献１には、廃棄物に含まれる重金属を難溶化するための方法が記載されている。特許文献１においては、キレート剤を用いて重金属が凝集させられる。 Incinerator fly ash is generated by incineration of waste in the incinerator. Incinerator fly ash contains heavy metals. Therefore, the incinerated fly ash is subjected to an intermediate treatment to prevent the elution of heavy metals, and then landfilled at the final disposal site. For example, Patent Document 1 describes a method for making heavy metals contained in waste sparingly soluble. In Patent Document 1, heavy metals are aggregated using a chelating agent.
特開２０１４－２３７１１４号公報Japanese Unexamined Patent Publication No. 2014-237114
　しかし、焼却飛灰に含まれる重金属の難溶化のためにキレート剤を用いる場合、重金属の難溶化を確実に行うため、余剰のキレート剤を使用するが、処理後の焼却飛灰からキレート剤等が溶出し、有機物の負荷となる。また、余剰のキレート剤は、廃棄物から発生する浸出水の水処理の硝化工程における硝化反応を阻害してしまう。これらのため、最終処分場において、廃棄物から発生する浸出水の水処理の負荷が大きくなる可能性がある。 However, when a chelating agent is used to make the heavy metal contained in the incinerated fly ash sparingly soluble, a surplus chelating agent is used to ensure that the heavy metal is sparingly soluble. Elutes and becomes a load of organic matter. In addition, the excess chelating agent inhibits the nitrification reaction in the nitrification step of water treatment of leachate generated from waste. For these reasons, the load of water treatment of leachate generated from waste may increase at the final disposal site.
　本開示は、上記の課題に鑑みてなされたものであって、焼却飛灰に含まれる重金属の溶出を抑制でき且つキレート剤由来の有機物の溶出を抑制できる焼却飛灰の処理方法を提供することを目的とする。 The present disclosure has been made in view of the above problems, and provides a method for treating incinerated fly ash, which can suppress the elution of heavy metals contained in incinerated fly ash and can suppress the elution of organic substances derived from a chelating agent. With the goal.
　上記の目的を達成するため、本開示の一態様の焼却飛灰の処理方法は、ケイ素化合物及びアルミニウム化合物の少なくとも一方を含む添加物と焼却飛灰とを混練して混合物を作成する混練工程と、前記混合物に対して炭酸化処理を施す炭酸化工程と、を備える。 In order to achieve the above object, the method for treating incinerated fly ash according to one aspect of the present disclosure includes a kneading step of kneading an additive containing at least one of a silicon compound and an aluminum compound and incinerated fly ash to prepare a mixture. The mixture is provided with a carbonation step of subjecting the mixture to a carbonation treatment.
　焼却飛灰の処理方法の望ましい態様として、前記添加物は、焼却主灰である。 As a desirable embodiment of the method for treating incinerated fly ash, the additive is incinerator main ash.
　焼却飛灰の処理方法の望ましい態様として、前記添加物は、ケイ酸ナトリウム水溶液、コンクリート破砕物、セメントに含まれるカルシウム系化合物もしくは溶融物、又はシリカ鉱物を含む岩石もしくは砕屑物である。 As a desirable embodiment of the method for treating incinerated fly ash, the additive is an aqueous sodium silicate solution, crushed concrete, a calcium compound or melt contained in cement, or rock or debris containing silica mineral.
　焼却飛灰の処理方法の望ましい態様として、焼却主灰を大粒径灰と前記大粒径灰よりも最大粒径が小さい小粒径灰とに分ける分離工程を備え、前記添加物は、前記小粒径灰である。 As a desirable embodiment of the method for treating incinerated fly ash, a separation step of separating the incinerated main ash into a large particle size ash and a small particle size ash having a smaller maximum particle size than the large particle size ash is provided, and the additive is the above-mentioned additive. Small particle size ash.
　焼却飛灰の処理方法の望ましい態様として、焼却主灰を水で洗浄することによって大粒径灰と前記大粒径灰よりも最大粒径が小さい小粒径灰とに分ける分離工程を備え、前記添加物は、前記小粒径灰である。 As a desirable embodiment of the method for treating incinerated fly ash, a separation step of washing the incinerated main ash with water to separate it into a large particle size ash and a small particle size ash having a smaller maximum particle size than the large particle size ash is provided. The additive is the small particle size ash.
　焼却飛灰の処理方法の望ましい態様として、焼却主灰を水で洗浄する洗浄工程を備え、前記添加物は、前記洗浄工程で前記焼却主灰の洗浄に用いられた洗浄排水である。 As a desirable embodiment of the method for treating incinerated fly ash, a cleaning step of cleaning the incinerated main ash with water is provided, and the additive is the cleaning wastewater used for cleaning the incinerated main ash in the cleaning step.
　焼却飛灰の処理方法の望ましい態様として、焼却主灰に対して炭酸化処理を施す事前炭酸化工程と、前記事前炭酸化工程で炭酸化された前記焼却主灰を水で洗浄する洗浄工程と、を備え、前記添加物は、前記洗浄工程で前記焼却主灰の洗浄に用いられた洗浄排水である。 As a desirable embodiment of the method for treating the incinerated flying ash, a pre-carbonation step of performing a carbonization treatment on the incinerated main ash and a washing step of washing the incinerated main ash carbonized in the pre-carbonation step with water. The additive is the cleaning wastewater used for cleaning the incineration main ash in the cleaning step.
　焼却飛灰の処理方法の望ましい態様として、ケイ素化合物及びアルミニウム化合物の少なくとも一方を含む鉱物を水で洗浄する洗浄工程を備え、前記添加物は、前記洗浄工程で前記鉱物の洗浄に用いられた洗浄排水である。 A preferred embodiment of the method for treating incinerated flying ash includes a washing step of washing a mineral containing at least one of a silicon compound and an aluminum compound with water, and the additive is used for washing the mineral in the washing step. It is drainage.
　本開示の焼却飛灰の処理方法によれば、焼却飛灰に含まれる重金属の溶出を抑制でき且つキレート剤由来の有機物の溶出を抑制できる。 According to the incinerated fly ash treatment method of the present disclosure, the elution of heavy metals contained in the incinerated fly ash can be suppressed and the elution of organic substances derived from the chelating agent can be suppressed.
図１は、第１実施形態の焼却飛灰の処理方法を示すフローチャートである。FIG. 1 is a flowchart showing a method for treating incinerated fly ash according to the first embodiment. 図２は、焼却飛灰から溶出する鉛の濃度に関する実験結果を示すグラフである。FIG. 2 is a graph showing the experimental results regarding the concentration of lead eluted from incinerated fly ash. 図３は、焼却主灰及び焼却飛灰の含有成分を示す図である。FIG. 3 is a diagram showing components contained in the incinerator main ash and the incinerator fly ash. 図４は、焼却飛灰から溶出する鉛の濃度に関する実験結果を示すグラフである。FIG. 4 is a graph showing the experimental results regarding the concentration of lead eluted from incinerated fly ash. 図５は、第２実施形態の焼却飛灰の処理方法を示すフローチャートである。FIG. 5 is a flowchart showing a method for treating incinerated fly ash according to the second embodiment. 図６は、第３実施形態の焼却飛灰の処理方法を示すフローチャートである。FIG. 6 is a flowchart showing a method for treating incinerated fly ash according to the third embodiment. 図７は、第３実施形態の変形例の焼却飛灰の処理方法を示すフローチャートである。FIG. 7 is a flowchart showing a method for treating incinerated fly ash according to a modified example of the third embodiment. 図８は、焼却主灰から溶出するアルミニウムの濃度に関する実験結果を示すグラフである。FIG. 8 is a graph showing the experimental results regarding the concentration of aluminum eluted from the incinerator main ash.
　以下、本発明につき図面を参照しつつ詳細に説明する。なお、本発明を実施するための形態（以下、実施形態という）により本発明が限定されるものではない。また、下記実施形態における構成要素には、当業者が容易に想定できるもの、実質的に同一のもの、いわゆる均等の範囲のものが含まれる。さらに、下記実施形態で開示した構成要素は適宜組み合わせることが可能である。 Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiment for carrying out the present invention (hereinafter referred to as the embodiment). In addition, the components in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, that is, those in a so-called equal range. Further, the components disclosed in the following embodiments can be appropriately combined.
（第１実施形態）
　図１は、第１実施形態の焼却飛灰の処理方法を示すフローチャートである。焼却施設から排出される焼却灰は、焼却主灰と焼却飛灰とに分かれる。焼却飛灰には、鉛（Ｐｂ）等の重金属が含まれている。焼却飛灰に含まれる重金属は溶出しやすいので、焼却飛灰は、埋め立てられる前に、重金属が溶出しないように処理される。第１実施形態の焼却飛灰の処理方法は、焼却施設から排出される焼却飛灰から重金属が溶出することを抑制するための方法である。 (First Embodiment)
FIG. 1 is a flowchart showing a method for treating incinerated fly ash according to the first embodiment. The incinerator ash discharged from the incinerator is divided into incinerator ash and incinerator fly ash. Incinerator fly ash contains heavy metals such as lead (Pb). Since the heavy metals contained in the incinerator fly ash are easily eluted, the incinerator fly ash is treated so that the heavy metals do not elute before being landfilled. The method for treating incinerated fly ash of the first embodiment is a method for suppressing the elution of heavy metals from the incinerated fly ash discharged from the incinerator.
　図１に示すように、第１実施形態の焼却飛灰の処理方法は、混練工程Ｓ１１と、炭酸化工程Ｓ１２と、を備える。混練工程Ｓ１１は、ケイ素化合物（Ｓｉ化合物）及びアルミニウム化合物（Ａｌ化合物）の少なくとも一方を含む添加物と焼却飛灰とを混練する工程である。ケイ素化合物としては、例えば二酸化ケイ素（ＳｉＯ２）が挙げられる。アルミニウム化合物としては、例えばポリ塩化アルミニウム（ＰＡＣ）、酸化アルミニウム（Ａｌ２Ｏ３）が挙げられる。 As shown in FIG. 1, the method for treating incinerated fly ash of the first embodiment includes a kneading step S11 and a carbonation step S12. The kneading step S11 is a step of kneading the additive containing at least one of the silicon compound (Si compound) and the aluminum compound (Al compound) with the incinerated fly ash. Examples of the silicon compound include silicon dioxide (SiO 2 ). Examples of the aluminum compound include polyaluminum chloride (PAC) and aluminum oxide (Al 2 O 3 ).
　混練工程Ｓ１１において、例えば乾燥重量で２ｔの焼却飛灰に対して２１３ｋｇの二酸化ケイ素と５０５ｋｇの水が添加され混練される。また、混練工程Ｓ１１において、例えば乾燥重量で２ｔの焼却飛灰に対して４５７ｋｇの酸化アルミニウムが添加され混練される。 In the kneading step S11, for example, 213 kg of silicon dioxide and 505 kg of water are added to 2 tons of incinerated fly ash by dry weight and kneaded. Further, in the kneading step S11, for example, 457 kg of aluminum oxide is added to incinerated fly ash having a dry weight of 2 tons and kneaded.
　炭酸化工程Ｓ１２は、混練工程Ｓ１１で作成された混合物に対して炭酸化処理を施す工程である。炭酸化処理は、混合物に炭酸ガス（二酸化炭素（ＣＯ２）ガス）を触れさせる処理である。炭酸化工程Ｓ１２では、容器（炭酸化処理槽）に混合物が配置される。容器は、例えば略直方体状のコンテナである。容器は、内部空間を鉛直方向に分割する隔壁を備える。隔壁は、容器の底面と平行な板状部材であって、複数の通気口を備える。混合物は、隔壁の上に置かれる。隔壁の上に混合物が載った状態で、隔壁の下側の空間に炭酸ガスが導入される。炭酸ガスは、隔壁の通気口を通って混合物に接触する。混合物は、炭酸ガスを吸収することで炭酸化する。 The carbonation step S12 is a step of subjecting the mixture prepared in the kneading step S11 to a carbonation treatment. The carbonation treatment is a treatment in which the mixture is exposed to carbon dioxide gas (carbon dioxide (CO 2 ) gas). In the carbonation step S12, the mixture is arranged in a container (carbonation treatment tank). The container is, for example, a substantially rectangular parallelepiped container. The container is provided with a partition wall that vertically divides the internal space. The partition wall is a plate-shaped member parallel to the bottom surface of the container and includes a plurality of vents. The mixture is placed on the bulkhead. Carbon dioxide is introduced into the space below the bulkhead with the mixture resting on the bulkhead. Carbon dioxide contacts the mixture through the vents in the bulkhead. The mixture is carbonated by absorbing carbon dioxide.
　炭酸化工程Ｓ１２において、例えば容量が８ｍ３のコンテナが容器として用いられる。コンテナの中に、混練工程Ｓ１１で作成された混合物が３０ｃｍ以上５０ｃｍ以下程度の厚さで均一に置かれる。そして、コンテナの隔壁の下部から６時間に亘って、混合物１ｋｇ当たり６０ｇの炭酸ガスが通気される。炭酸化工程Ｓ１２において、セメント系水和生成物及びケイ酸ソーダの少なくとも一方を炭酸化することができる。 In the carbonation step S12, for example, a container having a capacity of 8 m 3 is used as a container. The mixture prepared in the kneading step S11 is uniformly placed in the container to a thickness of about 30 cm or more and 50 cm or less. Then, 60 g of carbon dioxide gas per 1 kg of the mixture is aerated from the lower part of the partition wall of the container for 6 hours. In the carbonation step S12, at least one of the cement-based hydration product and sodium silicate can be carbonated.
　なお、混練工程Ｓ１１の後、３時間以上４８時間以下、又は６時間以上２４時間以下の養生工程を行ってもよい。 After the kneading step S11, a curing step of 3 hours or more and 48 hours or less, or 6 hours or more and 24 hours or less may be performed.
　第１実施形態では、混練工程Ｓ１１において水を添加することにより、添加物の一例であるセメントに含まれるカルシウム系化合物の水和反応が生じる。これにより、セメント系水和生成物を生成することができる。また、水を添加することにより、焼却飛灰中のアルカリ成分と添加物であるシリカが反応するアルカリシリカ反応が生じる。これにより、ケイ酸ソーダを生成することができる。また、炭酸化工程Ｓ１２において、セメント系水和生成物及びケイ酸ソーダが炭酸化され、鉱物が生成される。当該鉱物は、重金属を吸蔵又は吸着することが可能である。 In the first embodiment, by adding water in the kneading step S11, a hydration reaction of a calcium compound contained in cement, which is an example of an additive, occurs. This makes it possible to produce a cement-based hydration product. Further, by adding water, an alkali-silica reaction occurs in which the alkaline component in the incinerator fly ash reacts with silica as an additive. This makes it possible to produce sodium silicate. Further, in the carbonation step S12, the cement-based hydration product and sodium silicate are carbonated to produce minerals. The mineral can occlude or adsorb heavy metals.
　また、混練工程Ｓ１１の後に養生工程を行うことにより、水和反応とポゾラン反応が進行する。ポゾラン反応において、セメント系水和反応生成物である水酸化カルシウムと添加物に含まれる二酸化ケイ素及び酸化アルミニウムとが反応する。この結果、混練物のｐＨの低下が生じ、混練物中の焼却飛灰に含まれる重金属の溶解度を低減することができる。 Further, by performing the curing step after the kneading step S11, the hydration reaction and the pozzolan reaction proceed. In the pozzolan reaction, calcium hydroxide, which is a cement-based hydration reaction product, reacts with silicon dioxide and aluminum oxide contained in the additive. As a result, the pH of the kneaded product is lowered, and the solubility of heavy metals contained in the incinerated fly ash in the kneaded product can be reduced.
　以上の結果、焼却飛灰に含まれる重金属の溶出量を低減することができる。 As a result of the above, the amount of heavy metals eluted in the incinerated fly ash can be reduced.
　第１実施形態の焼却飛灰の処理方法に関して実験（以下、第１実験という）が行われた。第１実験では、異なる処理方法で処理された６つの焼却飛灰に対して、溶出する鉛の濃度が測定された。実験対象としての６つの試料を、第１比較例、第２比較例、第３比較例、第４比較例、第１実施例、第２実施例とする。図２は、焼却飛灰から溶出する鉛の濃度に関する第１実験結果を示すグラフである。 An experiment (hereinafter referred to as the first experiment) was conducted on the method for treating the incinerated fly ash of the first embodiment. In the first experiment, the concentration of lead eluted was measured for 6 incinerated fly ash treated by different treatment methods. The six samples as experimental objects are referred to as a first comparative example, a second comparative example, a third comparative example, a fourth comparative example, a first example, and a second example. FIG. 2 is a graph showing the results of the first experiment regarding the concentration of lead eluted from incinerated fly ash.
　第１比較例は、何の処理もしていない焼却飛灰である。第２比較例は、炭酸化のみ施された焼却飛灰である。第３比較例は、二酸化ケイ素と焼却飛灰の混合物である。第３比較例では、１ｋｇの焼却飛灰に対して５３．２ｇの二酸化ケイ素が添加された。第３比較例は、炭酸化されていない。第４比較例は、ポリ塩化アルミニウムと焼却飛灰の混合物である。第４比較例では、１ｋｇの焼却飛灰に対して１１４．２ｇのポリ塩化アルミニウムが添加された。第４比較例は、炭酸化されていない。 The first comparative example is incinerated fly ash that has not been treated at all. The second comparative example is incinerated fly ash that has been subjected to carbonation only. The third comparative example is a mixture of silicon dioxide and incinerated fly ash. In the third comparative example, 53.2 g of silicon dioxide was added to 1 kg of incinerated fly ash. The third comparative example is not carbonated. The fourth comparative example is a mixture of polyaluminum chloride and incinerated fly ash. In the fourth comparative example, 114.2 g of polyaluminum chloride was added to 1 kg of incinerated fly ash. The fourth comparative example is not carbonated.
　第１実施例は、二酸化ケイ素と焼却飛灰の混合物を炭酸化したものである。すなわち、第１実施例は、上述した第１実施形態の焼却飛灰の処理方法によって処理された焼却飛灰である。第１実施例では、混練工程Ｓ１１において、１ｋｇの焼却飛灰に対して５３．２ｇの二酸化ケイ素が添加された。 The first embodiment is a carbonated mixture of silicon dioxide and incinerator fly ash. That is, the first embodiment is the incinerator fly ash treated by the method for treating the incinerator fly ash of the first embodiment described above. In the first embodiment, 53.2 g of silicon dioxide was added to 1 kg of incinerated fly ash in the kneading step S11.
　第２実施例は、ポリ塩化アルミニウムと焼却飛灰の混合物を炭酸化したものである。すなわち、第２実施例は、上述した第１実施形態の焼却飛灰の処理方法によって処理された焼却飛灰である。第２実施例では、混練工程Ｓ１１において、１ｋｇの焼却飛灰に対して１１４．２ｇのポリ塩化アルミニウムが添加された。 The second embodiment is a carbonated mixture of polyaluminum chloride and incinerated fly ash. That is, the second embodiment is the incinerator fly ash treated by the method for treating the incinerator fly ash of the first embodiment described above. In the second embodiment, 114.2 g of polyaluminum chloride was added to 1 kg of incinerated fly ash in the kneading step S11.
　第２比較例、第１実施例及び第２実施例の炭酸化処理は、焼却飛灰（又は混合物）の含水率が２０％になるように水分調整がなされた後、炭酸ガスを通気することによって行われた。より具体的には、炭酸化処理は、１．８時間に亘って行われた。１．８時間で通気される炭酸ガスの量は、１ｋｇの焼却飛灰（又は混合物）当たり６０ｇであった。 In the carbonation treatment of the second comparative example, the first example and the second example, carbon dioxide gas is aerated after the water content is adjusted so that the water content of the incinerated fly ash (or mixture) is 20%. Made by. More specifically, the carbonation treatment was carried out for 1.8 hours. The amount of carbon dioxide aerated in 1.8 hours was 60 g per 1 kg of incinerated fly ash (or mixture).
　第１実験では、まず試料に１０倍量の純水を加えてから、６時間振とうされた。その後、試料は、遠心分離器によって固体と液体に分離された。分離した溶液は、孔径が１．０μｍのメンブレンフィルターで濾過された。そして、濾過された溶液の鉛の濃度（ｍｇ／Ｌ）が測定された。図２に示すように、第１実施例及び第２実施例から溶出する鉛の濃度は、第１比較例から溶出する鉛の濃度に対して非常に小さい。以下の説明において、低減率を用いる。低減率は、第１比較例の測定結果（溶出する鉛の濃度）に対する、各試料の測定結果と第１比較例の測定結果との差の比を百分率で表した値である。すなわち、低減率をＲ、第１比較例の測定結果をＳ１、その他の試料の測定結果をＳxとすると、低減率は下記式（１）で表される。 In the first experiment, 10 times the amount of pure water was first added to the sample, and then the sample was shaken for 6 hours. The sample was then separated into solid and liquid by a centrifuge. The separated solution was filtered through a membrane filter having a pore size of 1.0 μm. Then, the lead concentration (mg / L) of the filtered solution was measured. As shown in FIG. 2, the concentration of lead eluted from the first example and the second embodiment is very small with respect to the concentration of lead eluted from the first comparative example. In the following description, the reduction rate will be used. The reduction rate is a value obtained by expressing the ratio of the difference between the measurement result of each sample and the measurement result of the first comparative example to the measurement result (concentration of eluted lead) of the first comparative example as a percentage. That is, assuming that the reduction rate is R, the measurement result of the first comparative example is S 1 , and the measurement result of other samples is S x , the reduction rate is expressed by the following equation (1).
　Ｒ＝（Ｓ１－Ｓx）×１００／Ｓ１　・・・（１） R = (S 1- S x ) x 100 / S 1 ... (1)
　第２比較例の低減率は、約３２％に留まる。第３比較例の低減率は、約１６％に留まる。第４比較例の低減率は、約２４％に留まる。これに対して、第１実施例の低減率は、約９９．５％である。第２実施例の低減率は、約９９．４％である。 The reduction rate of the second comparative example remains at about 32%. The reduction rate of the third comparative example remains at about 16%. The reduction rate of the fourth comparative example remains at about 24%. On the other hand, the reduction rate of the first embodiment is about 99.5%. The reduction rate of the second embodiment is about 99.4%.
　以上で説明したように、第１実施形態の焼却飛灰の処理方法は、混練工程Ｓ１１と、炭酸化工程Ｓ１２と、を備える。混練工程Ｓ１１は、ケイ素化合物及びアルミニウム化合物の少なくとも一方を含む添加物と焼却飛灰とを混練して混合物を作成する工程である。炭酸化工程Ｓ１２は、混合物に対して炭酸化処理を施す工程である。 As described above, the method for treating the incinerated fly ash of the first embodiment includes a kneading step S11 and a carbonation step S12. The kneading step S11 is a step of kneading an additive containing at least one of a silicon compound and an aluminum compound with incinerated fly ash to prepare a mixture. The carbonation step S12 is a step of subjecting the mixture to a carbonation treatment.
　これにより、炭酸化工程Ｓ１２における重金属の不溶化、及び重金属が他の物質へ吸蔵又は吸着される等の理由によって、重金属の溶出が抑制される。また、第１実施形態の焼却飛灰の処理方法では、キレート剤を使用せずに重金属の溶出を抑制できる。したがって、第１実施形態の焼却飛灰の処理方法は、焼却飛灰に含まれる重金属の溶出を抑制でき且つキレート剤を使用しないことでキレート剤由来の有機物の溶出を抑制できる。 As a result, the elution of the heavy metal is suppressed due to the insolubilization of the heavy metal in the carbonation step S12 and the reason that the heavy metal is occluded or adsorbed to another substance. Further, in the method for treating incinerated fly ash of the first embodiment, elution of heavy metals can be suppressed without using a chelating agent. Therefore, the method for treating incinerated fly ash of the first embodiment can suppress the elution of heavy metals contained in the incinerated fly ash, and can suppress the elution of organic substances derived from the chelating agent by not using the chelating agent.
　（第１実施形態の変形例）
　第１実施形態の変形例の焼却飛灰の処理方法では、混練工程Ｓ１１において、添加物として焼却主灰が用いられる。すなわち、混練工程Ｓ１１においては、添加物としての焼却主灰と、焼却飛灰とが混練される。第１実施形態の変形例の混練工程Ｓ１１において、例えば乾燥重量で１ｔの焼却飛灰に対して、乾燥重量で１ｔの焼却主灰が添加され混練される。そして、炭酸化工程Ｓ１２では、混練工程Ｓ１１で作成された焼却主灰及び焼却飛灰の混合物に対して炭酸化処理が施される。 (Modified example of the first embodiment)
In the method for treating incinerator fly ash of the modified example of the first embodiment, incinerator main ash is used as an additive in the kneading step S11. That is, in the kneading step S11, the incinerator main ash as an additive and the incinerator fly ash are kneaded. In the kneading step S11 of the modified example of the first embodiment, for example, 1 ton of incinerator fly ash by dry weight is added to 1 ton of incinerator fly ash by dry weight and kneaded. Then, in the carbonation step S12, the carbonation treatment is performed on the mixture of the incinerator main ash and the incinerator fly ash produced in the kneading step S11.
　図３は、焼却主灰及び焼却飛灰の含有成分を示す図である。図３は、焼却主灰及び焼却飛灰の含有成分を、散乱線ＦＰ法を用いて分析した結果である。図３は、焼却主灰及び焼却飛灰のそれぞれに含まれる物質の質量パーセント濃度を示す。図３中のＢａｌａｎｃｅは、散乱線ＦＰ法で測定されなかった物質を示す。図３に示すように、焼却主灰に含まれる二酸化ケイ素（ＳｉＯ２）は、焼却飛灰に含まれる二酸化ケイ素の約１０倍である。焼却主灰に含まれる酸化アルミニウム（Ａｌ２Ｏ３）は、焼却飛灰に含まれる酸化アルミニウムの約４０倍である。このため、添加物として焼却主灰が用いられることによって、焼却飛灰にケイ素化合物及びアルミニウム化合物を供給することが可能である。また、焼却主灰に含まれる酸化鉄（Ｆｅ２Ｏ３）は、焼却飛灰に含まれる酸化鉄の約８．５倍である。焼却主灰に多く含まれる酸化鉄（Ｆｅ２Ｏ３）は、重金属を吸着する。このため、焼却主灰は、重金属の溶出の抑制に寄与する。 FIG. 3 is a diagram showing components contained in the incinerator main ash and the incinerator fly ash. FIG. 3 shows the results of analysis of the components contained in the incinerator main ash and the incinerator fly ash using the scattered radiation FP method. FIG. 3 shows the mass percent concentration of the substance contained in each of the incinerator main ash and the incinerator fly ash. Balance in FIG. 3 indicates a substance that was not measured by the scattered radiation FP method. As shown in FIG. 3, the amount of silicon dioxide (SiO 2 ) contained in the incinerator main ash is about 10 times that of silicon dioxide contained in the incinerator fly ash. The amount of aluminum oxide (Al 2 O 3 ) contained in the incineration main ash is about 40 times that of the aluminum oxide contained in the incineration fly ash. Therefore, by using the incinerator main ash as an additive, it is possible to supply the silicon compound and the aluminum compound to the incinerator fly ash. The amount of iron oxide (Fe 2 O 3 ) contained in the incinerated main ash is about 8.5 times that of iron oxide contained in the incinerated flying ash. Iron oxide (Fe 2 O 3 ), which is abundant in incinerator ash, adsorbs heavy metals. Therefore, the incinerator main ash contributes to the suppression of elution of heavy metals.
　第１実施形態の変形例の焼却飛灰の処理方法に関して実験（以下、第２実験という）が行われた。第２実験では、異なる処理方法で処理された４つの焼却飛灰に対して、溶出する鉛の濃度が測定された。実験対象としての４つの試料を、第５比較例、第６比較例、第７比較例、第３実施例とする。図２は、焼却飛灰から溶出する鉛の濃度に関する第２実験結果を示すグラフである。 An experiment (hereinafter referred to as a second experiment) was conducted on a method for treating incinerated fly ash in a modified example of the first embodiment. In the second experiment, the concentration of lead eluted was measured for four incinerated fly ash treated by different treatment methods. The four samples as experimental objects are referred to as a fifth comparative example, a sixth comparative example, a seventh comparative example, and a third example. FIG. 2 is a graph showing the results of the second experiment regarding the concentration of lead eluted from incinerated fly ash.
　第５比較例は、何の処理もしていない焼却飛灰である。第６比較例は、炭酸化のみ施された焼却飛灰である。第７比較例は、焼却主灰と焼却飛灰の混合物である。第７比較例では、焼却飛灰に対して同量の焼却主灰が添加された。第７比較例は、炭酸化されていない混合物である。 The fifth comparative example is incinerated fly ash that has not been treated at all. The sixth comparative example is incinerated fly ash that has been subjected to carbonation only. The seventh comparative example is a mixture of incinerator main ash and incinerator fly ash. In the seventh comparative example, the same amount of incinerator main ash was added to the incinerator fly ash. A seventh comparative example is a non-carbonated mixture.
　第３実施例は、焼却主灰と焼却飛灰の混合物を炭酸化したものである。すなわち、第３実施例は、第１実施形態の変形例の焼却飛灰の処理方法によって処理された焼却飛灰である。第３実施例では、混練工程Ｓ１１において、焼却飛灰に対しての同量の焼却主灰が添加された。 The third embodiment is a carbonated mixture of incinerator main ash and incinerator fly ash. That is, the third embodiment is the incinerator fly ash treated by the method for treating the incinerator fly ash of the modified example of the first embodiment. In the third embodiment, in the kneading step S11, the same amount of incinerator main ash as the incinerator fly ash was added.
　第６比較例及び第３実施例の炭酸化処理は、焼却飛灰（又は混合物）の含水率が２０％になるように水分調整がなされた後、炭酸ガスを通気することによって行われた。より具体的には、炭酸化処理は、１．８時間に亘って行われた。１．８時間で通気される炭酸ガスの量は、１ｋｇの焼却飛灰（又は混合物）当たり６０ｇであった。 The carbonation treatment of the 6th Comparative Example and the 3rd Example was carried out by aerating carbon dioxide gas after adjusting the water content so that the water content of the incinerated fly ash (or mixture) was 20%. More specifically, the carbonation treatment was carried out for 1.8 hours. The amount of carbon dioxide aerated in 1.8 hours was 60 g per 1 kg of incinerated fly ash (or mixture).
　第２実験では、まず試料に１０倍量の純水を加えてから、６時間振とうされた。その後、試料は、遠心分離器によって固体と液体に分離された。分離した溶液は、孔径が１．０μｍのメンブレンフィルターで濾過された。そして、濾過された溶液の鉛の濃度（ｍｇ／Ｌ）が測定された。図４に示すように、第３実施例から溶出する鉛の濃度は、第５比較例から溶出する鉛の濃度に対して非常に小さい。第６比較例の低減率は、約８１％に留まる。第７比較例の低減率は、約６０％に留まる。これに対して、第３実施例の低減率は、約９９．７％である。 In the second experiment, 10 times the amount of pure water was first added to the sample, and then the sample was shaken for 6 hours. The sample was then separated into solid and liquid by a centrifuge. The separated solution was filtered through a membrane filter having a pore size of 1.0 μm. Then, the lead concentration (mg / L) of the filtered solution was measured. As shown in FIG. 4, the concentration of lead eluted from the third example is very small with respect to the concentration of lead eluted from the fifth comparative example. The reduction rate of the sixth comparative example remains at about 81%. The reduction rate of the seventh comparative example remains at about 60%. On the other hand, the reduction rate of the third embodiment is about 99.7%.
　上述したように、第１実施形態の変形例の焼却飛灰の処理方法において、添加物は、焼却主灰である。 As described above, in the method for treating incinerated fly ash of the modified example of the first embodiment, the additive is the incinerator main ash.
　焼却主灰にケイ素化合物及びアルミニウム化合物が多く含まれているので、混練工程Ｓ１１において、焼却飛灰にケイ素化合物及びアルミニウム化合物を容易に供給することが可能となる。焼却主灰は、焼却施設において焼却飛灰と共に生成されるものであるので、容易に調達できる。このため、添加物としてケイ素化合物又はアルミニウム化合物を使用する場合と比較して、添加物に費やすコストを低減できる。また、焼却主灰に含まれる酸化鉄によって、重金属の溶出がより抑制される。したがって、第１実施形態の変形例の焼却飛灰の処理方法によれば、より容易に焼却飛灰を処理できる。 Since the main ash to be incinerated contains a large amount of silicon compounds and aluminum compounds, it is possible to easily supply the silicon compounds and aluminum compounds to the incinerated fly ash in the kneading step S11. Since the incinerator main ash is produced together with the incinerated fly ash in the incinerator, it can be easily procured. Therefore, the cost spent on the additive can be reduced as compared with the case where the silicon compound or the aluminum compound is used as the additive. In addition, iron oxide contained in the incinerator main ash further suppresses the elution of heavy metals. Therefore, according to the method for treating incinerator fly ash of the modified example of the first embodiment, the incinerator fly ash can be treated more easily.
　（第２実施形態）
　第２実施形態では、焼却主灰を大粒径灰と小粒径灰に分離し、小粒径灰を選択的に用いて焼却飛灰を処理する方法について説明する。大粒径灰とは、塊状の灰（クリンカ）、スラグ等である。小粒径灰とは、粒径が５ｍｍ以下の灰である。小粒径灰は、大粒径灰と比較して比表面積が大きいため、焼却飛灰との混錬の際に、ケイ素化合物及びアルミニウム化合物の溶出量を増加させることができる。 (Second Embodiment)
In the second embodiment, a method of separating the incinerator main ash into a large particle size ash and a small particle size ash and selectively using the small particle size ash to treat the incinerated fly ash will be described. The large particle size ash is a lumpy ash (clinker), slag, or the like. The small particle size ash is an ash having a particle size of 5 mm or less. Since the small particle size ash has a larger specific surface area than the large particle size ash, the elution amount of the silicon compound and the aluminum compound can be increased during kneading with the incinerated fly ash.
　図５は、第２実施形態の焼却飛灰の処理方法を示すフローチャートである。図５に示すように、第２実施形態の焼却飛灰の処理方法は、分離工程Ｓ２１と、混練工程Ｓ２２と、炭酸化工程Ｓ２３と、を備える。 FIG. 5 is a flowchart showing a method for treating incinerated fly ash according to the second embodiment. As shown in FIG. 5, the method for treating incinerated fly ash of the second embodiment includes a separation step S21, a kneading step S22, and a carbonation step S23.
　分離工程Ｓ２１は、焼却主灰を大粒径灰と小粒径灰とに分ける工程である。小粒径灰の最大粒径は、大粒径灰の最小粒径よりも小さい。言い換えると、小粒径灰は、焼却主灰の分けられた２つのグループのうち最大粒径が小さいグループである。例えば、小粒径灰の粒径は、５ｍｍ以下である。より具体的には、目開きが５ｍｍのメッシュを通過する焼却主灰が小粒径灰である。目開きが５ｍｍのメッシュを通過しない焼却主灰が大粒径灰である。なお、小粒径灰の粒径は、必ずしも５ｍｍ以下でなくてもよく、特に限定されない。焼却主灰は、例えばふるいによって大粒径灰と小粒径灰とに分離される。なお、焼却主灰は、水で洗浄することによって大粒径灰と小粒径灰とに分離されてもよい。 Separation step S21 is a step of separating the incinerator main ash into large particle size ash and small particle size ash. The maximum particle size of the small particle size ash is smaller than the minimum particle size of the large particle size ash. In other words, the small particle size ash is the group with the smallest maximum particle size among the two divided groups of the incinerator main ash. For example, the particle size of the small particle size ash is 5 mm or less. More specifically, the incinerator main ash that passes through a mesh having a mesh opening of 5 mm is a small particle size ash. The incinerator main ash that does not pass through the mesh with a mesh size of 5 mm is the large particle size ash. The particle size of the small particle size ash does not necessarily have to be 5 mm or less, and is not particularly limited. The incinerator main ash is separated into a large particle size ash and a small particle size ash by, for example, a sieve. The incinerator main ash may be separated into a large particle size ash and a small particle size ash by washing with water.
　混練工程Ｓ２２では、分離工程Ｓ２１で生成された小粒径灰と焼却飛灰とが混練される。すなわち、混練工程Ｓ２２において、添加物としての小粒径灰と焼却飛灰とが混練される。炭酸化工程Ｓ２３は、混練工程Ｓ２２で作成された混合物に対して炭酸化処理を施す工程である。 In the kneading step S22, the small particle size ash produced in the separation step S21 and the incinerator fly ash are kneaded. That is, in the kneading step S22, the small particle size ash as an additive and the incinerator fly ash are kneaded. The carbonation step S23 is a step of subjecting the mixture prepared in the kneading step S22 to a carbonation treatment.
　上述したように、第２実施形態の焼却飛灰の処理方法は、焼却主灰を大粒径灰と大粒径灰よりも最大粒径が小さい小粒径灰とに分ける分離工程Ｓ２１を備える。混練工程Ｓ２２における添加物は、小粒径灰である。 As described above, the method for treating the incinerated fly ash of the second embodiment includes a separation step S21 for separating the incinerated main ash into a large particle size ash and a small particle size ash having a smaller maximum particle size than the large particle size ash. .. The additive in the kneading step S22 is a small particle size ash.
　焼却主灰の一部である小粒径灰は表面積が大きく、ケイ素化合物及びアルミニウム化合物の溶出量が多いので、混練工程Ｓ２２において焼却飛灰にケイ素化合物及びアルミニウム化合物を容易に供給することが可能となる。さらに、焼却主灰の全部と焼却飛灰とを混練する場合と比較して、粒径の小さい小粒径灰は、焼却飛灰と容易に混練することができる。また、焼却主灰は、焼却施設において焼却飛灰と共に生成されるものであるので、容易に調達できる。このため、添加物としてケイ素化合物又はアルミニウム化合物を使用する場合と比較して、添加物に費やすコストを低減できる。また、小粒径灰は、大粒径灰よりも多くのケイ素化合物及びアルミニウム化合物を溶出することができるので、小粒径灰及び大粒径灰の両方を添加する場合と比較して、添加物の量を低減できる。さらに、小粒径灰は大粒径灰よりも多くの重金属を含む。焼却主灰に含まれる重金属の多くが焼却飛灰と混練されて難溶化されることになるので、残渣である大粒径灰に含まれる重金属は少なくなる。このため、焼却主灰（大粒径灰）のリサイクルがより容易となる。焼却主灰（大粒径灰）は、例えばセメントの原料又は土木資材としてリサイクルされる。 Since the small particle size ash, which is a part of the main ash to be incinerated, has a large surface area and a large amount of elution of the silicon compound and the aluminum compound, it is possible to easily supply the silicon compound and the aluminum compound to the incinerated fly ash in the kneading step S22. It becomes. Further, the small particle size ash having a smaller particle size can be easily kneaded with the incinerator fly ash as compared with the case where the entire incinerator ash and the incinerator fly ash are kneaded. Moreover, since the incinerator main ash is produced together with the incinerated fly ash in the incinerator, it can be easily procured. Therefore, the cost spent on the additive can be reduced as compared with the case where the silicon compound or the aluminum compound is used as the additive. Further, since the small particle size ash can elute more silicon compounds and aluminum compounds than the large particle size ash, it is added as compared with the case where both the small particle size ash and the large particle size ash are added. The amount of things can be reduced. In addition, small particle size ash contains more heavy metals than large particle size ash. Since most of the heavy metals contained in the incinerator main ash are kneaded with the incinerator fly ash and hardly dissolved, the amount of heavy metals contained in the residual large particle size ash is reduced. Therefore, the incinerator main ash (large particle size ash) can be easily recycled. The incinerator main ash (large particle size ash) is recycled, for example, as a raw material for cement or a civil engineering material.
　上述したように、第２実施形態の焼却飛灰の処理方法は、焼却主灰を水で洗浄することによって大粒径灰と大粒径灰よりも最大粒径が小さい小粒径灰とに分ける分離工程Ｓ２１を備える。混練工程Ｓ２２における添加物は、小粒径灰である。 As described above, the method for treating the incinerated fly ash of the second embodiment is to wash the incinerator main ash with water to obtain a large particle size ash and a small particle size ash having a smaller maximum particle size than the large particle size ash. A separation step S21 for separating is provided. The additive in the kneading step S22 is a small particle size ash.
　これにより、焼却主灰を大粒径灰と小粒径灰とに容易に分離できる。 As a result, the incinerator main ash can be easily separated into large particle size ash and small particle size ash.
　（第３実施形態）
　第３実施形態では、焼却主灰を洗浄した洗浄排水を用いて、焼却飛灰を処理する方法について説明する。 (Third Embodiment)
In the third embodiment, a method of treating incinerator fly ash using the washing wastewater obtained by washing the incinerator main ash will be described.
　図６は、第３実施形態の焼却飛灰の処理方法を示すフローチャートである。図６に示すように、第３実施形態の焼却飛灰の処理方法は、洗浄工程Ｓ３２と、混練工程Ｓ３３と、炭酸化工程Ｓ３４と、を備える。 FIG. 6 is a flowchart showing a method for treating incinerated fly ash according to the third embodiment. As shown in FIG. 6, the method for treating incinerated fly ash according to the third embodiment includes a cleaning step S32, a kneading step S33, and a carbonation step S34.
　洗浄工程Ｓ３２は、焼却主灰を水で洗浄する工程である。洗浄工程Ｓ３２で生じる洗浄排水は、焼却主灰と接した水である。洗浄を行うことにより、水溶性のケイ素成分やアルミニウム成分を溶出させることができる。 The cleaning step S32 is a step of cleaning the incinerator main ash with water. The cleaning wastewater generated in the cleaning step S32 is water in contact with the incinerator main ash. By washing, the water-soluble silicon component and aluminum component can be eluted.
　混練工程Ｓ３３では、洗浄工程Ｓ３２で生じた洗浄排水と焼却飛灰とが混練される。すなわち、混練工程Ｓ３３において、添加物としての洗浄排水と焼却飛灰とが混練される。炭酸化工程Ｓ３４は、混練工程Ｓ３３で作成された混合物に対して炭酸化処理を施す工程である。 In the kneading step S33, the washing wastewater generated in the washing step S32 and the incinerator fly ash are kneaded. That is, in the kneading step S33, the washing wastewater as an additive and the incinerator fly ash are kneaded. The carbonation step S34 is a step of subjecting the mixture prepared in the kneading step S33 to a carbonation treatment.
　上述したように、第３実施形態の焼却飛灰の処理方法は、焼却主灰を水で洗浄する洗浄工程Ｓ３２を備える。混練工程Ｓ３３における添加物は、洗浄工程Ｓ３２で焼却主灰の洗浄に用いられた洗浄排水である。 As described above, the method for treating incinerator fly ash according to the third embodiment includes a cleaning step S32 for cleaning the incinerator main ash with water. The additive in the kneading step S33 is the washing wastewater used for washing the incinerator main ash in the washing step S32.
　焼却主灰を通過した洗浄排水にはケイ素やアルミニウム成分が含まれているので、混練工程Ｓ３３において焼却飛灰にケイ素・アルミニウム化合物を容易に供給することが可能となる。焼却主灰は、焼却施設において焼却飛灰と共に生成されるものであるので、容易に調達できる。このため、添加物としてケイ素化合物又はアルミニウム化合物を使用する場合と比較して、添加物に費やすコストを低減できる。さらに、洗浄排水は、洗浄残渣よりも多くの重金属を含む。焼却主灰に含まれる重金属の多くが焼却飛灰と混練されて難溶化されることになるので、洗浄残渣に含まれる重金属は少なくなる。このため、焼却主灰（洗浄残渣）のリサイクルがより容易となる。焼却主灰（洗浄残渣）は、例えばセメントの原料又は土木資材としてリサイクルされる。 Since the washing wastewater that has passed through the incinerator main ash contains silicon and aluminum components, it is possible to easily supply the silicon / aluminum compound to the incinerator fly ash in the kneading step S33. Since the incinerator main ash is produced together with the incinerated fly ash in the incinerator, it can be easily procured. Therefore, the cost spent on the additive can be reduced as compared with the case where the silicon compound or the aluminum compound is used as the additive. In addition, the wash effluent contains more heavy metals than the wash residue. Most of the heavy metals contained in the incinerator main ash are kneaded with the incinerator fly ash to be poorly soluble, so that the amount of heavy metals contained in the cleaning residue is reduced. Therefore, it becomes easier to recycle the incinerator main ash (cleaning residue). The incinerator ash (cleaning residue) is recycled, for example, as a raw material for cement or a civil engineering material.
　（第３実施形態の変形例）
　第３実施形態の変形例では、炭酸化された焼却主灰を洗浄した洗浄排水を用いて、焼却飛灰を処理する方法について説明する。 (Modified example of the third embodiment)
In the modified example of the third embodiment, a method of treating the incinerator fly ash by using the washing wastewater obtained by washing the carbonated incinerator main ash will be described.
　図７は、第３実施形態の変形例の焼却飛灰の処理方法を示すフローチャートである。図７に示すように、第３実施形態の変形例の焼却飛灰の処理方法は、事前炭酸化工程Ｓ３１と、洗浄工程Ｓ３２と、混練工程Ｓ３３と、炭酸化工程Ｓ３４と、を備える。 FIG. 7 is a flowchart showing a method for treating incinerated fly ash in a modified example of the third embodiment. As shown in FIG. 7, the method for treating the incinerated fly ash of the modified example of the third embodiment includes a pre-carbonation step S31, a cleaning step S32, a kneading step S33, and a carbonation step S34.
　事前炭酸化工程Ｓ３１は、焼却主灰に対して炭酸化処理を施す工程である。炭酸化した焼却主灰に関して実験（以下、第３実験という）が行われた。第３実験では、炭酸化していない焼却主灰と、炭酸化した焼却主灰に対して、溶出するアルミニウムの濃度が測定された。第３実験では、試料に１０倍量の純水を加えてから、６時間振とうされた。その後、試料は、遠心分離器によって固体と液体に分離された。分離した溶液は、孔径が１．０μｍのメンブレンフィルターで濾過された。濾過された溶液のアルミニウムの濃度（ｍｇ／Ｌ）が測定された。 The pre-carbonation step S31 is a step of carbonating the incinerator main ash. An experiment (hereinafter referred to as the third experiment) was conducted on the carbonated incinerator ash. In the third experiment, the concentration of eluted aluminum was measured with respect to the uncarbonated incinerator ash and the carbonated incinerator ash. In the third experiment, 10 times the amount of pure water was added to the sample, and then the sample was shaken for 6 hours. The sample was then separated into solid and liquid by a centrifuge. The separated solution was filtered through a membrane filter having a pore size of 1.0 μm. The concentration of aluminum (mg / L) in the filtered solution was measured.
　図８は、焼却主灰から溶出するアルミニウムの濃度に関する実験結果を示すグラフである。図８に示すように、炭酸化していない焼却主灰に対して、炭酸化した焼却主灰から溶出するアルミニウムの濃度は非常に高くなる。 FIG. 8 is a graph showing the experimental results regarding the concentration of aluminum eluted from the incinerator main ash. As shown in FIG. 8, the concentration of aluminum eluted from the carbonated incinerator ash is much higher than that of the uncarbonated incinerator ash.
　洗浄工程Ｓ３２は、事前炭酸化工程Ｓ３１で炭酸化された焼却主灰を水で洗浄する工程である。洗浄工程Ｓ３２で生じる洗浄排水は、炭酸化された焼却主灰と接した水である。このため、洗浄排水には、多量のアルミニウムが溶出している。 The cleaning step S32 is a step of cleaning the incinerator ash carbonated in the pre-carbonation step S31 with water. The washing wastewater generated in the washing step S32 is water in contact with the carbonated incinerator ash. Therefore, a large amount of aluminum is eluted in the washing wastewater.
　上述したように、第３実施形態の変形例の焼却飛灰の処理方法は、焼却主灰に対して炭酸化処理を施す事前炭酸化工程Ｓ３１と、事前炭酸化工程Ｓ３１で炭酸化された焼却主灰を水で洗浄する洗浄工程Ｓ３２と、を備える。混練工程Ｓ３３における添加物は、洗浄工程Ｓ３２で焼却主灰の洗浄に用いられた洗浄排水である。 As described above, the method for treating the incinerated fly ash of the modified example of the third embodiment is the pre-carbonation step S31 in which the incinerated main ash is carbonated and the incineration carbonated in the pre-carbonation step S31. A cleaning step S32 for cleaning the main ash with water is provided. The additive in the kneading step S33 is the washing wastewater used for washing the incinerator main ash in the washing step S32.
　炭酸化した焼却主灰を通過した洗浄排水にはアルミニウムが多く含まれているので、混練工程Ｓ３３において焼却飛灰にアルミニウム化合物を容易に供給することが可能となる。焼却主灰は、焼却施設において焼却飛灰と共に生成されるものであるので、容易に調達できる。このため、添加物としてケイ素化合物又はアルミニウム化合物を使用する場合と比較して、添加物に費やすコストを低減できる。さらに、洗浄排水は、洗浄残渣よりも多くの重金属を含む。焼却主灰に含まれる重金属の多くが焼却飛灰と混練されて難溶化されることになるので、洗浄残渣に含まれる重金属は少なくなる。このため、焼却主灰（洗浄残渣）のリサイクルがより容易となる。焼却主灰（洗浄残渣）は、例えばセメントの原料又は土木資材としてリサイクルされる。 Since the washing wastewater that has passed through the carbonated incinerator main ash contains a large amount of aluminum, it is possible to easily supply the aluminum compound to the incinerator fly ash in the kneading step S33. Since the incinerator main ash is produced together with the incinerated fly ash in the incinerator, it can be easily procured. Therefore, the cost spent on the additive can be reduced as compared with the case where the silicon compound or the aluminum compound is used as the additive. In addition, the wash effluent contains more heavy metals than the wash residue. Most of the heavy metals contained in the incinerator main ash are kneaded with the incinerator fly ash to be poorly soluble, so that the amount of heavy metals contained in the cleaning residue is reduced. Therefore, it becomes easier to recycle the incinerator main ash (cleaning residue). The incinerator ash (cleaning residue) is recycled, for example, as a raw material for cement or a civil engineering material.
　なお、第３実施形態、及び第３実施形態の変形例において、焼却主灰に代えて、ケイ素化合物及びアルミニウム化合物の少なくとも一方を含む鉱物が水で洗浄されてもよい。鉱物は、例えば、コンクリート破砕物、セメントに含まれるカルシウム系化合物（エーライト、ビーライト、アルミネート相、フェライト相）もしくは溶融物（スラグ）、又はシリカ鉱物を含む岩石もしくは砕屑物（火成岩（石英、トリディマイト，クリストバライト，コーサイト，スティショバイト等）、堆積岩（珪藻土））等である。シリカを含む鉱物は、アルカリ性溶液で洗浄すると、シリカの溶解度が高くなるため好ましい。 In the third embodiment and the modified examples of the third embodiment, the mineral containing at least one of the silicon compound and the aluminum compound may be washed with water instead of the incinerator main ash. Minerals include, for example, crushed concrete, calcium-based compounds (acrite, belite, aluminate phase, ferrite phase) or melts (slag) contained in cement, or rocks or debris containing silica minerals (igneous rock (quartz)). , Tridimite, Cristobalite, Coesite, Stishovite, etc.), Sedimentary rock (diatomaceous soil)), etc. Minerals containing silica are preferable when washed with an alkaline solution because the solubility of silica increases.
　上述したように、第３実施形態、及び第３実施形態の変形例において、焼却飛灰の処理方法は、ケイ素化合物及びアルミニウム化合物の少なくとも一方を含む鉱物を水で洗浄する洗浄工程Ｓ３２を備えてもよい。混練工程Ｓ３３における添加物は、洗浄工程Ｓ３２で鉱物の洗浄に用いられた洗浄排水である。 As described above, in the third embodiment and the modified example of the third embodiment, the method for treating the incinerated fly ash includes a washing step S32 for washing a mineral containing at least one of a silicon compound and an aluminum compound with water. May be good. The additive in the kneading step S33 is the washing wastewater used for washing the minerals in the washing step S32.
　鉱物を通過した洗浄排水にはケイ素化合物又はアルミニウム化合物が含まれているので、混練工程Ｓ３３において焼却飛灰にケイ素化合物又はアルミニウム化合物を容易に供給することが可能となる。 Since the washing wastewater that has passed through the mineral contains a silicon compound or an aluminum compound, it is possible to easily supply the silicon compound or the aluminum compound to the incinerated fly ash in the kneading step S33.
（第４実施形態）
　第１実施形態において、ケイ素化合物及びアルミニウム化合物の少なくとも一方を含む添加物として焼却主灰を用いた。添加物としての焼却主灰の代わりに、コンクリート破砕物、セメントに含まれるカルシウム系化合物（エーライト、ビーライト、アルミネート相、フェライト相）もしくは溶融物（スラグ）、又はシリカ鉱物を含む岩石もしくは砕屑物（火成岩（石英、トリディマイト，クリストバライト，コーサイト，スティショバイト等）、堆積岩（珪藻土））等を用いることができる。また、第３実施形態の洗浄排水の代わりに、ケイ酸ナトリウム水溶液（水ガラス）を用いることができる。 (Fourth Embodiment)
In the first embodiment, incinerator ash was used as an additive containing at least one of a silicon compound and an aluminum compound. Instead of incineration main ash as an additive, crushed concrete, calcium-based compounds (acrite, belite, aluminate phase, ferrite phase) or melts (slag) contained in cement, or rocks containing silica minerals or Debris (igneous rock (quartz, tridimite, cristobalite, coesite, stishovite, etc.), sedimentary rock (diatomaceous soil)) and the like can be used. Further, instead of the washing wastewater of the third embodiment, an aqueous sodium silicate solution (water glass) can be used.
Ｓ１１　混練工程
Ｓ１２　炭酸化工程
Ｓ２１　分離工程
Ｓ２２　混練工程
Ｓ２３　炭酸化工程
Ｓ３１　事前炭酸化工程
Ｓ３２　洗浄工程
Ｓ３３　混練工程
Ｓ３４　炭酸化工程 S11 Kneading step S12 Carbonation step S21 Separation step S22 Kneading step S23 Carbonation step S31 Pre-carbonation step S32 Cleaning step S33 Kneading step S34 Carbonation step

Claims (8)

  1. 　ケイ素化合物及びアルミニウム化合物の少なくとも一方を含む添加物と焼却飛灰とを混練して混合物を作成する混練工程と、
    　前記混合物に対して炭酸化処理を施す炭酸化工程と、
    　を備える焼却飛灰の処理方法。     A kneading step of kneading an additive containing at least one of a silicon compound and an aluminum compound and incinerator fly ash to prepare a mixture.
    A carbonation step of applying a carbonation treatment to the mixture, and
    A method of treating incinerated fly ash.
  2. 　前記添加物は、焼却主灰である
    　請求項１に記載の焼却飛灰の処理方法。     The method for treating incinerated fly ash according to claim 1, wherein the additive is an incinerator main ash.
  3. 　前記添加物は、ケイ酸ナトリウム水溶液、コンクリート破砕物、セメントに含まれるカルシウム系化合物もしくは溶融物、又はシリカ鉱物を含む岩石もしくは砕屑物である
    　請求項１に記載の焼却飛灰の処理方法。     The method for treating incinerated fly ash according to claim 1, wherein the additive is an aqueous sodium silicate solution, crushed concrete, a calcium compound or melt contained in cement, or rock or debris containing silica mineral.
  4. 　焼却主灰を大粒径灰と前記大粒径灰よりも最大粒径が小さい小粒径灰とに分ける分離工程を備え、
    　前記添加物は、前記小粒径灰である
    　請求項２に記載の焼却飛灰の処理方法。     It is provided with a separation step of separating the incinerator main ash into a large particle size ash and a small particle size ash having a smaller maximum particle size than the large particle size ash.
    The method for treating incinerated fly ash according to claim 2, wherein the additive is the small particle size ash.
  5. 　焼却主灰を水で洗浄することによって大粒径灰と前記大粒径灰よりも最大粒径が小さい小粒径灰とに分ける分離工程を備え、
    　前記添加物は、前記小粒径灰である
    　請求項２に記載の焼却飛灰の処理方法。     A separation step is provided in which the main ash to be incinerated is washed with water to separate it into a large particle size ash and a small particle size ash having a smaller maximum particle size than the large particle size ash.
    The method for treating incinerated fly ash according to claim 2, wherein the additive is the small particle size ash.
  6. 　焼却主灰を水で洗浄する洗浄工程を備え、
    　前記添加物は、前記洗浄工程で前記焼却主灰の洗浄に用いられた洗浄排水である
    　請求項１に記載の焼却飛灰の処理方法。     Equipped with a cleaning process to wash the incinerator ash with water
    The method for treating incinerator fly ash according to claim 1, wherein the additive is cleaning wastewater used for cleaning the incinerator main ash in the cleaning step.
  7. 　焼却主灰に対して炭酸化処理を施す事前炭酸化工程と、
    　前記事前炭酸化工程で炭酸化された前記焼却主灰を水で洗浄する洗浄工程と、
    　を備え、
    　前記添加物は、前記洗浄工程で前記焼却主灰の洗浄に用いられた洗浄排水である
    　請求項１に記載の焼却飛灰の処理方法。     Pre-carbonation process to carbonate the incinerator ash and
    A washing step of washing the incinerator ash carbonated in the pre-carbonation step with water, and a washing step.
    With
    The method for treating incinerator fly ash according to claim 1, wherein the additive is cleaning wastewater used for cleaning the incinerator main ash in the cleaning step.
  8. 　ケイ素化合物及びアルミニウム化合物の少なくとも一方を含む鉱物を水で洗浄する洗浄工程を備え、
    　前記添加物は、前記洗浄工程で前記鉱物の洗浄に用いられた洗浄排水である
    　請求項１に記載の焼却飛灰の処理方法。     A washing step of washing minerals containing at least one of a silicon compound and an aluminum compound with water is provided.
    The method for treating incinerated fly ash according to claim 1, wherein the additive is a washing wastewater used for washing the mineral in the washing step.
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