JP7457793B2 - How to dispose of incinerated fly ash - Google Patents

Description

The present invention relates to a method for treating incineration fly ash.

Incineration fly ash is generated by incineration of waste in incineration facilities. Incineration fly ash contains heavy metals. For this reason, incinerated fly ash undergoes intermediate treatment to prevent the elution of heavy metals, and then is disposed of in a landfill at a final disposal site. For example, Patent Document 1 describes a method for making heavy metals contained in waste materials insoluble. In Patent Document 1, heavy metals are aggregated using a chelating agent.

Japanese Patent Application Publication No. 2014-237114

However, when using a chelating agent to make the heavy metals contained in the incinerated fly ash difficult to dissolve, excess chelating agent is used to ensure that the heavy metals are made insoluble; is eluted and becomes a load of organic matter. In addition, excess chelating agent inhibits the nitrification reaction in the nitrification process of water treatment of leachate generated from waste. For these reasons, the burden 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 an object of the present disclosure is to provide a method for treating incinerated fly ash that can suppress the elution of heavy metals contained in the incinerated fly ash and suppress the elution of organic substances derived from chelating agents. With the goal.

In order to achieve the above object, a method for treating incineration fly ash according to one embodiment of the present disclosure includes a kneading step of kneading an additive containing at least one of a silicon compound and an aluminum compound with the incineration fly ash to prepare a mixture, and a carbonation step of subjecting the mixture to a carbonation treatment.

In a desirable embodiment of the method for treating incinerated fly ash, the additive is incinerated bottom ash.

In a desirable embodiment of the method for treating incinerated fly ash, the additive is an aqueous sodium silicate solution, crushed concrete, a calcium-based compound or melt contained in cement, or rock or crushed debris containing silica minerals.

A desirable embodiment of the method for treating incinerated fly ash includes a separation step of separating the incinerated bottom ash into large particle size ash and small particle size ash having a smaller maximum particle size than the large particle size ash, and the additive is It is small particle size ash.

A desirable embodiment of the method for treating incinerated fly ash includes a separation step of separating incinerated bottom ash into large particle size ash and small particle size ash having a smaller maximum particle size than the large particle size ash by washing the incineration bottom ash with water, The additive is the small particle size ash.

A desirable embodiment of the method for treating incinerated fly ash includes a washing step of washing the incinerated bottom ash with water, and the additive is washing wastewater used for washing the incinerated bottom ash in the washing step.

A desirable embodiment of the method for treating incinerated fly ash includes a pre-carbonation step in which the incinerated bottom ash is carbonated, and a washing step in which the incinerated bottom ash carbonated in the preliminary carbonation step is washed with water. and the additive is cleaning wastewater used for cleaning the incineration bottom ash in the cleaning step.

A desirable embodiment of the method for treating incinerated fly 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 added to the washing used for washing the mineral in the washing step. It is wastewater.

According to the incineration fly ash treatment method disclosed herein, the leaching of heavy metals contained in the incineration fly ash can be suppressed, and the leaching of organic matter derived from chelating agents 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 experimental results regarding the concentration of lead eluted from incinerated fly ash. FIG. 3 is a diagram showing the components contained in incinerated bottom ash and incinerated fly ash. FIG. 4 is a graph showing 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 flow chart showing a method for treating incineration fly ash according to the third embodiment. FIG. 7 is a flowchart showing a method for treating incinerated fly ash according to a modification of the third embodiment. FIG. 8 is a graph showing experimental results regarding the concentration of aluminum eluted from the incineration bottom ash.

Hereinafter, the present invention will be explained in detail with reference to the drawings. Note that the present invention is not limited to the modes for carrying out the present invention (hereinafter referred to as embodiments). Furthermore, the constituent elements in the embodiments below include those that can be easily imagined by those skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the embodiments below can be combined as appropriate.

(First embodiment)
FIG. 1 is a flowchart showing a method for treating incinerated fly ash according to the first embodiment. Incineration ash discharged from incineration facilities is divided into incineration bottom ash and incineration fly ash. Incineration fly ash contains heavy metals such as lead (Pb). Since the heavy metals contained in incinerated fly ash are easily eluted, incinerated fly ash is treated to prevent heavy metals from leaching out before being landfilled. The method for treating incinerated fly ash according to the first embodiment is a method for suppressing the elution of heavy metals from incinerated fly ash discharged from an incineration facility.

As shown in FIG. 1, the method for treating incinerated fly ash according to the first embodiment includes a kneading step S11 and a carbonation step S12. The kneading step S11 is a step of kneading incinerated fly ash with an additive containing at least one of a silicon compound (Si compound) and an aluminum compound (Al compound). Examples of silicon compounds include silicon dioxide (SiO ₂ ). Examples of the aluminum compound include polyaluminum chloride (PAC) and aluminum oxide (Al ₂ O ₃ ).

In the kneading step S11, for example, 213 kg of silicon dioxide and 505 kg of water are added and kneaded to 2 t of incinerated fly ash in terms of dry weight. Further, in the kneading step S11, for example, 457 kg of aluminum oxide is added to 2 t of dry weight of incinerated fly ash and kneaded.

The carbonation step S12 is a step in which the mixture created in the kneading step S11 is carbonated. Carbonation treatment is a treatment in which a mixture is brought into contact with carbon dioxide gas (carbon dioxide (CO ₂ ) gas). In the carbonation step S12, the mixture is placed in a container (carbonation treatment tank). The container is, for example, a substantially rectangular parallelepiped container. The container includes a partition wall that vertically divides the interior space. The partition wall is a plate-like member parallel to the bottom surface of the container, and includes a plurality of vent holes. The mixture is placed on top of the septum. With the mixture on the partition wall, carbon dioxide gas is introduced into the space below the partition wall. Carbon dioxide gas contacts the mixture through vents in the septum. The mixture carbonates by absorbing carbon dioxide gas.

In the carbonation step S12, a container having a capacity of, for example, 8 m ³ is used as the 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. 60 g of carbon dioxide gas per kg of mixture is then vented through the lower part of the container wall over a period of 6 hours. In the carbonation step S12, at least one of the cement-based hydration product and the sodium silicate can be carbonated.

After the kneading process S11, a curing process may be carried out for 3 hours or more and 48 hours or less, or for 6 hours or more and 24 hours or less.

In the first embodiment, by adding water in the kneading step S11, a hydration reaction of calcium-based compounds contained in cement, which is an example of an additive, occurs. This makes it possible to produce a cement-based hydration product. Furthermore, by adding water, an alkali-silica reaction occurs in which the alkaline components in the incineration fly ash react with silica, which is an additive. This makes it possible to produce sodium silicate. Furthermore, in the carbonation step S12, the cement-based hydration product and sodium silicate are carbonated to produce a mineral. The mineral is capable of occluding or adsorbing heavy metals.

Further, by performing a curing step after the kneading step S11, the hydration reaction and the pozzolan reaction proceed. In the pozzolanic reaction, calcium hydroxide, which is a cement-based hydration reaction product, reacts with silicon dioxide and aluminum oxide contained in additives. As a result, the pH of the kneaded product decreases, and the solubility of heavy metals contained in the incinerated fly ash in the kneaded product can be reduced.

As a result, the amount of heavy metals contained in the incinerated fly ash can be reduced.

An experiment (hereinafter referred to as the first experiment) was conducted regarding the method for treating incinerated fly ash according to the first embodiment. In the first experiment, the concentration of leached lead was measured for six incinerated fly ash treated with different treatment methods. The six samples to be tested are 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 first experimental results regarding the concentration of lead eluted from incinerated fly ash.

Comparative Example 1 is incineration fly ash that has not been treated in any way. Comparative Example 2 is incineration fly ash that has only been carbonated. Comparative Example 3 is a mixture of silicon dioxide and incineration fly ash. In Comparative Example 3, 53.2 g of silicon dioxide was added to 1 kg of incineration fly ash. Comparative Example 3 is not carbonated. Comparative Example 4 is a mixture of polyaluminum chloride and incineration fly ash. In Comparative Example 4, 114.2 g of polyaluminum chloride was added to 1 kg of incineration fly ash. Comparative Example 4 is not carbonated.

In the first example, a mixture of silicon dioxide and incineration fly ash was carbonated. That is, the first example is incineration fly ash treated by the incineration fly ash treatment method of the first embodiment described above. In the first example, 53.2 g of silicon dioxide was added to 1 kg of incineration fly ash in the kneading step S11.

In the second example, a mixture of polyaluminum chloride and incinerated fly ash was carbonated. That is, the second example is incinerated fly ash treated by the method for treating incinerated fly ash of the first embodiment described above. In the second example, 114.2 g of polyaluminum chloride was added to 1 kg of incinerated fly ash in the kneading step S11.

In the carbonation treatment of the second comparative example, first example, and second example, after the moisture content of the incinerated fly ash (or mixture) is adjusted to 20%, carbon dioxide gas is aerated. It was done by. More specifically, the carbonation treatment was performed for 1.8 hours. The amount of carbon dioxide gas vented in 1.8 hours was 60 g per 1 kg of incinerated fly ash (or mixture).

In the first experiment, 10 times the volume 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 with a pore size of 1.0 μm. The lead concentration (mg/L) of the filtered solution was then measured. As shown in FIG. 2, the concentration of lead eluted from the first example and the second example is much smaller than 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 expressed as a percentage of the ratio of the difference between the measurement result of each sample and the measurement result of the first comparative example with respect to the measurement result (concentration of leached lead) of the first comparative example. That is, when the reduction rate is R, the measurement result of the first comparative example is S ₁ , and the measurement results of other samples are S _x , the reduction rate is expressed by the following formula (1).

R=(S ₁ -S _x )×100/S ₁ ...(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%. On the other hand, the reduction rate in the first example is about 99.5%. The reduction rate of the second example is approximately 99.4%.

As explained above, the method for treating incinerated fly ash according to the first embodiment includes a kneading step S11 and a carbonation step S12. The kneading step S11 is a step of kneading incinerated fly ash and an additive containing at least one of a silicon compound and an aluminum compound to create a mixture. The carbonation step S12 is a step in which the mixture is carbonated.

This suppresses the elution of heavy metals due to the insolubilization of heavy metals in the carbonation step S12 and the occlusion or adsorption of heavy metals into other substances. Furthermore, the method for treating incineration fly ash of the first embodiment can suppress the elution of heavy metals without using a chelating agent. Therefore, the method for treating incineration fly ash of the first embodiment can suppress the elution of heavy metals contained in incineration fly ash, and by not using a chelating agent, can suppress the elution of organic matter derived from the chelating agent.

(Modified example of the first embodiment)
In the method for treating incinerated fly ash as a modification of the first embodiment, incinerated bottom ash is used as an additive in the kneading step S11. That is, in the kneading step S11, incinerated bottom ash as an additive and incinerated fly ash are kneaded. In the kneading step S11 of the modification of the first embodiment, for example, 1 t of dry weight of incinerated bottom ash is added to 1 t of dry weight of incinerated fly ash and kneaded. Then, in the carbonation step S12, carbonation treatment is performed on the mixture of incinerated bottom ash and incinerated fly ash created in the kneading step S11.

FIG. 3 is a diagram showing the components contained in incinerated bottom ash and incinerated fly ash. FIG. 3 shows the results of analyzing the components contained in the incinerated bottom ash and incinerated fly ash using the scattered ray FP method. FIG. 3 shows the mass percent concentration of substances contained in each of the incinerated bottom ash and the incinerated fly ash. Balance in FIG. 3 indicates substances that were not measured by the scattered ray FP method. As shown in FIG. 3, the silicon dioxide (SiO ₂ ) contained in the incinerated bottom ash is about 10 times that of the silicon dioxide contained in the incinerated fly ash. The amount of aluminum oxide (Al ₂ O ₃ ) contained in the incinerated bottom ash is about 40 times that of the aluminum oxide contained in the incinerated fly ash. Therefore, by using the incinerated bottom ash as an additive, it is possible to supply silicon compounds and aluminum compounds to the incinerated fly ash. Further, the iron oxide (Fe ₂ O ₃ ) contained in the incinerated bottom ash is about 8.5 times that of the iron oxide contained in the incinerated fly ash. Iron oxide (Fe ₂ O ₃ ), which is contained in large amounts in the incineration bottom ash, adsorbs heavy metals. Therefore, the incineration bottom ash contributes to suppressing the elution of heavy metals.

An experiment (hereinafter referred to as a second experiment) was conducted regarding a method for treating incinerated fly ash as a modification of the first embodiment. In the second experiment, the concentration of leached lead was measured for four types of incinerated fly ash treated with different treatment methods. The four samples to be tested are 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 a second experiment regarding the concentration of lead eluted from incinerated fly ash.

The fifth comparative example is incinerated fly ash that has not been subjected to any treatment. The sixth comparative example is incinerated fly ash that has been subjected to only carbonation. The seventh comparative example is a mixture of incinerated bottom ash and incinerated fly ash. In the seventh comparative example, the same amount of incinerated bottom ash was added to the incinerated fly ash. The seventh comparative example is a non-carbonated mixture.

In the third example, a mixture of incineration bottom ash and incineration fly ash was carbonated. That is, the third example is incineration fly ash treated by the incineration fly ash treatment method of the modified example of the first embodiment. In the third example, in the kneading step S11, the same amount of incineration bottom ash was added to the incineration fly ash.

The carbonation treatment in the sixth comparative example and the third example was performed by aerating carbon dioxide gas after the moisture content of the incinerated fly ash (or mixture) was adjusted to 20%. More specifically, the carbonation treatment was performed for 1.8 hours. The amount of carbon dioxide gas vented in 1.8 hours was 60 g per 1 kg of incinerated fly ash (or mixture).

In the second experiment, 10 times the volume 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 with a pore size of 1.0 μm. The lead concentration (mg/L) of the filtered solution was then measured. As shown in FIG. 4, the concentration of lead eluted from the third example is much smaller than 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 example is about 99.7%.

As described above, in the method for treating incinerated fly ash according to the modification of the first embodiment, the additive is incinerated bottom ash.

Since the incineration bottom ash contains a large amount of silicon compounds and aluminum compounds, it is possible to easily supply silicon compounds and aluminum compounds to the incineration fly ash in the kneading step S11. The incineration bottom ash is easily procured because it is generated together with the incineration fly ash in the incineration facility. Therefore, the cost spent on additives can be reduced compared to using silicon compounds or aluminum compounds as additives. In addition, the iron oxide contained in the incineration bottom ash further suppresses the elution of heavy metals. Therefore, according to the incineration fly ash treatment method of the modified example of the first embodiment, the incineration fly ash can be treated more easily.

(Second embodiment)
In the second embodiment, a method will be described in which the incinerated bottom ash is separated into large particle size ash and small particle size ash, and the small particle size ash is selectively used to treat the incinerated fly ash. Large particle size ash includes lumpy ash (clinker), slag, and the like. Small particle size ash is ash with a particle size of 5 mm or less. Since small particle size ash has a larger specific surface area than large particle size ash, it is possible to increase the amount of silicon compounds and aluminum compounds eluted when mixed with incinerated fly ash.

Figure 5 is a flow chart showing a method for treating incineration fly ash according to a second embodiment. As shown in Figure 5, the method for treating incineration fly ash according to the second embodiment includes a separation process S21, a kneading process S22, and a carbonation process S23.

Separation step S21 is a step of separating the incineration bottom ash into large particle size ash and small particle size ash. The maximum particle size of small particle size ash is smaller than the minimum particle size of large particle size ash. In other words, the small particle size ash is a group with a smaller maximum particle size among the two groups of incineration bottom ash. For example, the particle size of small particle ash is 5 mm or less. More specifically, the incineration bottom ash that passes through a mesh with an opening of 5 mm is small particle size ash. Incineration bottom ash that does not pass through a mesh with an opening of 5 mm is large particle size ash. Note that 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 incineration bottom ash is separated into large particle size ash and small particle size ash, for example, by using a sieve. Incidentally, the incineration bottom ash may be separated into large particle size ash and small particle size ash by washing with water.

In the kneading process S22, the small-sized ash produced in the separation process S21 is kneaded with the incineration fly ash. That is, in the kneading process S22, the small-sized ash as an additive and the incineration fly ash are kneaded. The carbonation process S23 is a process in which the mixture produced in the kneading process S22 is carbonated.

As described above, the second embodiment of the incineration fly ash treatment method includes a separation process S21 in which the incineration bottom ash is separated into large particle size ash and small particle size ash having a smaller maximum particle size than the large particle size ash. The additive in the kneading process S22 is the small particle size ash.

Small particle size ash, which is a part of the incinerated bottom ash, has a large surface area and a large amount of eluted silicon compounds and aluminum compounds, so it is possible to easily supply silicon compounds and aluminum compounds to the incinerated fly ash in the kneading step S22. becomes. Furthermore, compared to the case where all of the incinerated bottom ash and incinerated fly ash are kneaded, the small particle size ash can be easily kneaded with the incinerated fly ash. Furthermore, since the incinerated bottom ash is produced together with the incinerated fly ash in the incineration facility, it can be easily procured. Therefore, the cost spent on additives can be reduced compared to the case where a silicon compound or an aluminum compound is used as an additive. In addition, small particle size ash can elute more silicon compounds and aluminum compounds than large particle size ash, so compared to the case where both small particle size ash and large particle size ash are added, The amount of material can be reduced. Furthermore, small particle size ash contains more heavy metals than large particle size ash. Since most of the heavy metals contained in the incinerated bottom ash are mixed with the incinerated fly ash and rendered insoluble, the amount of heavy metals contained in the large particle size ash that is the residue is reduced. Therefore, recycling of the incineration bottom ash (large particle size ash) becomes easier. Incineration bottom ash (large particle size ash) is recycled, for example, as a raw material for cement or as a civil engineering material.

As described above, the method for treating incinerated fly ash according to the second embodiment is to wash the incinerated main ash with water to convert it into large particle size ash and small particle size ash whose maximum particle size is smaller than the large particle size ash. A separation step S21 is provided. The additive in the kneading step S22 is small particle size ash.

Thereby, the incineration bottom ash can be easily separated into large particle size ash and small particle size ash.

(Third embodiment)
In the third embodiment, a method for treating incinerated fly ash using cleaning wastewater obtained by washing incinerated bottom ash will be described.

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.

The cleaning step S32 is a step of cleaning the incineration bottom ash with water. The cleaning wastewater generated in the cleaning step S32 is water that has come into contact with the incineration bottom ash. By washing, water-soluble silicon components and aluminum components can be eluted.

In the kneading process S33, the washing wastewater generated in the washing process S32 is kneaded with the incineration fly ash. That is, in the kneading process S33, the washing wastewater as an additive and the incineration fly ash are kneaded. The carbonation process S34 is a process in which the mixture created in the kneading process S33 is carbonated.

As described above, the third embodiment of the incineration fly ash treatment method includes a washing step S32 in which the incineration bottom ash is washed with water. The additive in the kneading step S33 is the washing wastewater used to wash the incineration bottom ash in the washing step S32.

Since the cleaning wastewater that has passed through the incinerated bottom ash contains silicon and aluminum components, it becomes possible to easily supply the silicon-aluminum compound to the incinerated fly ash in the kneading step S33. Incineration bottom ash is generated together with incineration fly ash in an incineration facility, so it can be easily procured. Therefore, the cost spent on additives can be reduced compared to the case where a silicon compound or an aluminum compound is used as an additive. Furthermore, the wash wastewater contains more heavy metals than the wash residue. Since most of the heavy metals contained in the incinerated bottom ash are mixed with the incinerated fly ash and rendered insoluble, the amount of heavy metals contained in the cleaning residue is reduced. Therefore, recycling of the incineration bottom ash (washing residue) becomes easier. The incineration bottom ash (washing residue) is recycled, for example, as a raw material for cement or as a civil engineering material.

(Modified example of third embodiment)
In a modification of the third embodiment, a method for treating incinerated fly ash using cleaning wastewater obtained by washing carbonated incinerated bottom ash will be described.

FIG. 7 is a flowchart showing a method for treating incinerated fly ash according to a modification of the third embodiment. As shown in FIG. 7, the method for treating incinerated fly ash according to the modification of the third embodiment includes a preliminary carbonation step S31, a washing step S32, a kneading step S33, and a carbonation step S34.

The preliminary carbonation step S31 is a step in which the incineration bottom ash is carbonated. An experiment (hereinafter referred to as the third experiment) was conducted on carbonated incineration bottom ash. In the third experiment, the concentration of eluted aluminum was measured for uncarbonated incineration bottom ash and carbonated incineration bottom ash. In the third experiment, 10 times the amount of pure water was added to the sample and then 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 with a pore size of 1.0 μm. The aluminum concentration (mg/L) of the filtered solution was measured.

FIG. 8 is a graph showing experimental results regarding the concentration of aluminum eluted from the incineration bottom ash. As shown in FIG. 8, the concentration of aluminum eluted from carbonated incineration bottom ash is much higher than that of non-carbonated incineration bottom ash.

The washing step S32 is a step of washing the incineration bottom ash carbonated in the preliminary carbonation step S31 with water. The cleaning wastewater generated in the cleaning step S32 is water that has come into contact with carbonated incineration bottom ash. Therefore, a large amount of aluminum is eluted into the cleaning wastewater.

As described above, the method for treating incinerated fly ash in the modified example of the third embodiment includes a pre-carbonation step S31 in which the incinerated bottom ash is carbonated, and an incineration process carbonated in the pre-carbonation step S31. A cleaning step S32 of cleaning the bottom ash with water is provided. The additive in the kneading step S33 is the cleaning waste water used for cleaning the incineration bottom ash in the cleaning step S32.

The washing wastewater that has passed through the carbonated incineration bottom ash contains a large amount of aluminum, so that it is possible to easily supply aluminum compounds to the incineration fly ash in the kneading process S33. The incineration bottom ash is easily procured because it is generated together with the incineration fly ash in the incineration facility. Therefore, compared to using silicon compounds or aluminum compounds as additives, the cost of additives can be reduced. Furthermore, the washing wastewater contains more heavy metals than the washing residue. Since many of the heavy metals contained in the incineration bottom ash are kneaded with the incineration fly ash and become insoluble, the amount of heavy metals contained in the washing residue is reduced. This makes it easier to recycle the incineration bottom ash (washing residue). The incineration bottom ash (washing residue) is recycled, for example, as a cement raw material or civil engineering material.

Note that in the third embodiment and a modification of the third embodiment, minerals containing at least one of a silicon compound and an aluminum compound may be washed with water instead of the incineration bottom ash. Minerals are, for example, crushed concrete, calcium-based compounds (alite, belite, aluminate phase, ferrite phase) or melts (slag) contained in cement, or rocks or debris containing silica minerals (igneous rock (quartz)). , tridymite, cristobalite, coesite, stishovite, etc.), and sedimentary rocks (diatomaceous earth). When minerals containing silica are washed with an alkaline solution, the solubility of silica increases, which is preferable.

As described above, in the third embodiment and the modification of the third embodiment, the method for treating incinerated fly ash includes a cleaning step S32 of cleaning minerals containing at least one of a silicon compound and an aluminum compound with water. Good too. The additive in the kneading step S33 is the cleaning waste water used for cleaning the minerals in the cleaning step S32.

Since the cleaning wastewater that has passed through the minerals contains silicon compounds or aluminum compounds, it becomes possible to easily supply the silicon compounds or aluminum compounds to the incinerated fly ash in the kneading step S33.

(Fourth embodiment)
In the first embodiment, incineration bottom ash was used as an additive containing at least one of a silicon compound and an aluminum compound. Instead of incineration bottom ash as an additive, crushed concrete, calcium-based compounds (alite, belite, aluminate phase, ferrite phase) or molten substances (slag) contained in cement, or rocks containing silica minerals or Detrital materials (igneous rocks (quartz, tridymite, cristobalite, coesite, stishovite, etc.), sedimentary rocks (diatomaceous earth)), etc. can be used. Moreover, a sodium silicate aqueous solution (water glass) can be used instead of the cleaning waste water in the third embodiment.

S11 Kneading process S12 Carbonation process S21 Separation process S22 Kneading process S23 Carbonation process S31 Pre-carbonation process S32 Washing process S33 Kneading process S34 Carbonation process

Claims (3)

a pre-carbonation step of performing carbonation treatment on incineration bottom ash containing at least one of a silicon compound and an aluminum compound;
A cleaning step of washing the incinerated bottom ash carbonated in the pre-carbonation step with water to generate washing wastewater that is a liquid that has come into contact with the incineration bottom ash;
a kneading step of kneading the washing wastewater and incinerated fly ash to create a mixture;
a carbonation step of performing carbonation treatment on the mixture;
A method for processing incinerated fly ash, comprising: a pre-carbonation step of performing carbonation treatment on a mineral containing at least one of a silicon compound and an aluminum compound;
a washing step of washing the mineral carbonated in the pre-carbonation step with water to produce washing wastewater, which is a liquid that has come into contact with the mineral;
a kneading step of kneading the washing wastewater and incinerated fly ash to create a mixture;
a carbonation step of performing carbonation treatment on the mixture ;
A method for processing incinerated fly ash, comprising: The method for treating incinerated fly ash according to claim 2 , wherein the mineral is a crushed concrete , a calcium-based compound or melt contained in cement, or a rock or debris containing a silica mineral.

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