JP6503898B2 - Processing method of incineration ash - Google Patents

Description

  The present invention suppresses the concentration of dioxins in incineration ash generated in the process of efficiently removing chlorine in incineration ash, makes the dewatered cake generated in the step of removing chlorine into cement raw material, and simultaneously generates the supernatant water generated. The present invention relates to a method of treating incineration ash to be treated with wastewater.

  It is known from the past to use the dewatered cake obtained by washing the incineration ash with water and desalting the chlorine in the incineration ash into a cement raw material. For example, in Patent Document 1, water is added to incineration ash to be suspended to elute chlorine, and dewatered cake obtained by dehydrating this with a dehydrator is used as cement raw material, and chlorine and heavy metal are eluted. There is disclosed a method of removing heavy metals and harmful components by adding washing wastewater to pH adjustment and using chelate and activated carbon in combination. Patent document 2 and patent document 3 add acid and an acidic substance to incineration ash, and by setting the pH of the slurry at the time of washing | cleaning to 6-10, while suppressing elution of heavy metals in incineration ash, incineration ash A method of removing chlorine in the medium is disclosed. Patent Document 4 discloses a method of removing dioxins contained in cleaning wastewater of chlorine-containing wastes using a microfiltration membrane.

JP 2002-338312 A Unexamined-Japanese-Patent No. 11-319729 gazette JP 10-202226 A JP, 2009-172552, A

However, Patent Document 1 does not describe anything regarding the dioxin treatment technology. Further, in the methods of Patent Documents 2 to 3, since dissolution of acid-soluble components such as calcium is promoted along with chlorine, harmful substances insoluble in dioxin and acid are concentrated in the dewatering cake, and the dewatering cake is made into cement raw material Problem. Moreover, patent document 4 is the method of using a precision filtration membrane for the process of dioxin, and installation cost becomes expensive.
Therefore, the present invention removes chlorine from incineration ash while suppressing the concentration of dioxins in the dewatering cake generated in the treatment process of incineration ash, and converts the generated dewatering cake into cement raw material, and dioxins contained in cleaning wastewater Aims to provide a method that can efficiently process

  As a result of intensive investigations to achieve the above object, the present inventors have found that when washing dioxin-containing incineration ash with water, a small amount of acid is added to make the pH of the slurry at the time of washing a specific range. The inventors have found that it is possible to efficiently remove chlorine in ash and at the same time suppress the concentration of dioxins in the dewatered cake, and make it possible to turn the dewatered cake into a cement raw material, thus completing the present invention. In addition, by using a specific pH adjuster with a high pH adjustment rate as a pH adjuster at the time of flocculation treatment, a large floc of dioxin adsorption amount can be generated, and the dioxin in the incineration ash cleaning wastewater can be efficiently used. It has been found that it can be removed well, and the present invention has been completed.

  That is, according to the present invention, water (1) is added to incineration ash and stirred and washed to prepare slurry (1), and then acid (1) is added to adjust pH to 10.5 to 12.5, and further polymer After the addition of the coagulant, the mixture is allowed to stand and solid-liquid separated into concentrated slurry (1) and supernatant water (1), and the concentrated slurry (1) is filtered to obtain dehydrated cake (2) and filtrate (2). A second step of solid-liquid separation into water), adding water (3) to the dehydrated cake (2), stirring and washing to prepare a slurry (3), adding a polymer flocculant, standing still, and concentration A third step of solid-liquid separation into slurry (3) and supernatant water (3), and a fourth step of solid-liquid separation of the concentrated slurry (3) into a dewatered cake (4) and a filtrate (4); Cement raw material forming step having a fifth step of using the dewatered cake (4) as cement raw material, and acid in the supernatant water (1) 6) Add and stir, adjust pH to 1 to 3 and add reducing agent, add inorganic flocculant, add sodium hydroxide and stir to adjust pH to 8 to 11 and leave still The present invention relates to a method of treating incinerated ash including a waste water treatment step having a sixth step of solid-liquid separation into precipitate and supernatant water (6).

According to the treatment method of the present invention, it is possible to provide a treatment method capable of efficiently removing chlorine in incinerated ash and suppressing the concentration of dioxins in the dewatered cake generated in the process.
Further, the first step of the present invention relates to a method of treating incineration ash, further comprising a seventh step of adding water (7) to dry ash to prepare the incineration ash.
According to the treatment method of the present invention, also in the case of dry ash, chlorine in the incineration ash can be efficiently removed, and a treatment method can be provided which suppresses the concentration of dioxins in the dewatered cake generated in the process.

  According to the method for treating incineration ash according to the present invention, it is possible to provide a treatment method for efficiently removing chlorine in the incineration ash and suppressing the concentration of dioxins in the dewatered cake generated in the process.

The processing flow of the incineration ash which concerns on a reference example is shown. The processing flow of the incineration ash which concerns on the Examples 1-3 of this invention, and the processing flow of the incineration ash which concerns on 1st-3rd embodiment of this invention are shown.

Hereinafter, a preferred embodiment of the present invention will be described in detail based on FIGS. 1 and 2. FIG.
<Method of treating incinerated ash>

The method for treating incineration ash according to the present embodiment includes a cement raw material forming step and a waste water treatment step.
Incineration ash is incineration ash generated in waste incinerators, etc., and is roughly classified into two types, main ash and incineration fly ash.
The main ash is the ash stored under the incinerator, and the incineration fly ash refers to the ash mainly collected by the dust collector of the incinerator. Main ash and incineration fly ash are further divided into two types, dry ash and wet ash. Both the main ash and the incineration fly ash are dry ash when discharged from the incinerator, which is called dry ash. Wet ash refers to ash that has been moistened with water over dry ash to prevent dust generation. The water content of the incinerated ash is more than 0% by mass and 30% by mass or less, preferably 0.1 to 28% by mass, more preferably 0.5 to 25% by mass, and still more preferably 5 to 20% by mass. More specifically, the water content in the case of dry ash is more than 0% by mass and 5% by mass or less, preferably 0.1 to 4% by mass, more preferably 0.2 to 3% by mass, and still more preferably 0. It is 3 to 2% by mass. The moisture content in the case of wet ash is 5 to 30% by mass, preferably 10 to 25% by mass, more preferably 15 to 22% by mass, and still more preferably 16 to 20% by mass. Within these ranges, it can be treated as incineration ash.

  In the cement raw material production process, water (1) is added to the incinerator ash and stirred and washed to prepare a slurry (1), then the acid (1) is added to adjust the pH to 10.5 to 12.5, and further polymer After the addition of the coagulant, the mixture is allowed to stand and solid-liquid separated into concentrated slurry (1) and supernatant water (1), and the concentrated slurry (1) is filtered to obtain dehydrated cake (2) and filtrate (2). A second step of solid-liquid separation into water), adding water (3) to the dehydrated cake (2), stirring and washing to prepare a slurry (3), adding a polymer flocculant, standing still, and concentration A third step of solid-liquid separation into slurry (3) and supernatant water (3), and a fourth step of solid-liquid separation of the concentrated slurry (3) into a dewatered cake (4) and a filtrate (4); And a fifth step of using the dewatered cake (4) as a cement raw material.

Stir washing means mixing incineration ash and water using a mixer or the like.
The acid (1) in the first step is one or more selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid. Among them, hydrochloric acid is more preferable because it is inexpensive and highly safe, and there is no generation of scale which causes clogging of piping and the like. Also, waste acid may be used. The waste acid refers to the acid waste liquid used for cleaning pipes, dehydrators, etc. in the treatment process of the incineration ash, acid waste liquid discharged from the chemical industry, steel and electric machinery industry and the like.

  The amount of water (1) added in the first step is preferably 1 to 10 times, more preferably 2 to 8 times, and more preferably 3 to 6 times the mass of the incinerated ash. Is more preferred. Within this range, a slurry in which the incineration ash is uniformly dispersed can be prepared, so that chlorine can be sufficiently eluted from the incineration ash.

  The amount of water (3) added in the third step is preferably 1 to 10 times, more preferably 2 to 8 times, and more preferably 3 to 6 times the mass of the incinerated ash. Is more preferred. Within these ranges, it is possible to prepare a slurry in which the dewatered cake (2) is uniformly dispersed, and to efficiently elute chlorine remaining in the dewatered cake (2). The chlorine concentration of the cake (4) can be reduced to the extent that it can be used as a cement raw material.

The first step may further include a seventh step of adding water (7) to dry ash to prepare the incineration ash. In the case of dry ash of main ash or incineration fly ash, water may be added, mixed with a mixer or the like to adjust the water content, and then treated as wet ash. The water content is preferably 5 to 30% by mass, and more preferably 10 to 20% by mass in terms of the content in the incineration ash.
As in the first embodiment of FIG. 2, since the filtrate (4) separated in the solid-liquid separation in the fourth step has chlorine, heavy metals and dioxins removed, it should be reused as water (1) in the first step. Is possible.

  In the waste water treatment step, acid (6) is added to the supernatant water (1) and stirred to adjust the pH to 1 to 3 to add a reducing agent, and then an inorganic coagulant is added, and then sodium hydroxide is added. The solution is stirred to adjust the pH to 8 to 11, and after standing, it has a sixth step of solid-liquid separation into a precipitate and supernatant water (6).

  The acid (6) in the sixth step is one or more selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid. With these acids, the pH can be adjusted to 1 to 3 without inhibiting removal of heavy metals and dioxins in the latter stage. Among them, hydrochloric acid is more preferable because it is inexpensive and highly safe, and there is no generation of scale which causes clogging of piping and the like. Also, waste acid may be used. The waste acid refers to the acid waste liquid used for cleaning pipes, dehydrators, etc. in the treatment process of the incineration ash, acid waste liquid discharged from the chemical industry, steel and electric machinery industry and the like.

The reducing agent in the sixth step is one or more selected from the group consisting of sodium bisulfite, sodium sulfite, ferrous chloride and ferrous sulfate.
The inorganic coagulant in the sixth step is one or more selected from the group consisting of ferric chloride, ferric sulfate and polyferric sulfate. These inorganic coagulants can form flocs to which heavy metals and dioxins are adsorbed in the range of pH 8 to 11, and the concentration thereof can be reduced to the drainage standard or lower of the sewerage law enforcement order. Among them, ferric chloride is particularly preferable in that it does not contain sulfate ion which causes scale.
Sodium hydroxide used as a pH adjuster in the sixth step has a faster pH adjustment rate than other alkalis, such as calcium hydroxide (slaked lime), calcium oxide (quick lime), etc. It is possible to reduce SS, increase the amount of dioxin adsorption to the precipitate, and increase the dioxin removal rate.

  As in the second embodiment of FIG. 2, since dioxins are concentrated in the solid phase (precipitate) separated in the solid-liquid separation in the sixth step, it is charged in the calciner to decompose dioxins instantaneously. It is also possible to use it by diluting it with other cement raw materials and diluting it. The liquid phase (filtrate) can be mixed with the supernatant water (6) of the sixth step and reprocessed together with the filtrate (2) of the second step and the supernatant water (3) of the third step.

  Further, as in the third embodiment of FIG. 2, since heavy metals and dioxins can be removed from the separated liquid phase (filtrate) separated in the solid-liquid separation in the sixth step, after confirming their concentrations, After pH adjustment, you may discharge. If heavy metals and dioxins can not be removed, they should be returned to the supernatant water (1) and reprocessed.

  The dioxin content of the dry ash is preferably 3 ng-TEQ / g or less based on the dry weight of the dry ash, more preferably 0.001 to 2.0 ng-TEQ / g, 0.0001 to 1.0 ng -TEQ / g is more preferred. Within these ranges, the content of dioxins concentrated in the dewatered cake (4) in the step of removing chlorine in dry ash can be suppressed to a level that can be used as a cement raw material.

The chemical components of the dry ash have an SiO ₂ content of 1 to 10 mass%, an Al ₂ O ₃ content of 1 to 8 mass%, and an Fe ₂ O ₃ content of 0. 1 based on the dry mass of the dry ash. 1-2 mass%, CaO content 20-50 mass%, MgO content 0.5-3.0 mass%, SO ₃ content 1.0-5.0 mass%, Cl content 10 To 30% by mass, Cr content is 0.03 to 0.1% by mass, Pb content is 0.05 to 0.2% by mass, Zn content is 0.2 to 0.5% by mass and Cd content Is preferably 0.003 to 0.01% by mass.
₂ to 8 mass% of SiO ₂ content, ₂ to 5 mass% of Al ₂ O ₃ content, 0.3 to 1.0 mass% of Fe ₂ O ₃ content, 30 to 40 mass% of CaO content MgO content is 1.0 to 2.0% by mass, SO ₃ content is 2.0 to 4.0% by mass, Cl content is 15 to 25% by mass, and Cr content is 0.05 to 0. 08% by mass, Pb content is 0.07 to 0.15% by mass, Zn content is 0.3 to 0.4% by mass, and Cd content is 0.005 to 0.008% by mass preferable. Within these ranges, chlorine in dry ash can be reduced to the extent that it can be used as a cement raw material, and the heavy metal concentration contained in the supernatant can be reduced by drainage treatment to below the drainage standard of the Sewage Law Enforcement Order.

  Examples and comparative examples are given below, and the contents of the present invention will be described in detail based on FIGS. 1 and 2. The present invention is not limited by these examples.

1. Incineration ash As incineration ash, the dry ash of municipal waste incineration fly ash was used. The characteristics of the dry ash of the incinerated fly ash subjected to the test are shown in Table 1. The chemical components in Table 1 are values measured by the following methods.
_{(I) SiO 2, Al 2} O 3, Fe 2 O 3, MgO, SO 3, measured SiO ₂ of _{R 2} O _{content, Al 2 O 3, Fe 2} O 3, MgO, SO 3, R 2 O content The amount was measured in accordance with JIS M 8853 “Method of chemical analysis of aluminosilicate material for ceramics”. The results are shown in Table 1.
(Ii) Measurement of CaO, Cl, Cr, Zn, Pb, Cd Content The CaO, Cl, Cr, Zn, Pb, Cd content was measured in accordance with JIS R 5202 "Method of chemical analysis of cement". The results are shown in Table 1.
(Iii) Measurement of dioxin content The dioxin content was measured in accordance with Ministry of Health and Welfare Notification No. 192, “Testing Standard for Specially Controlled General Waste and Specially Controlled Industrial Waste”.
(Iv) Measurement of Water Content The water content was measured by drying the dry ash of incineration fly ash at 50 ° C. for 16 hours in a drier.

2. Preparation of wet ash The dry ash of the incinerated fly ash was moistened to prepare wet ash, and used for the water washing desalting test of Test Example 1. Tap water was added to the dry ash of incinerated fly ash so that the moisture content of the wet ash was 18%, and mixed with a soil mixer to prepare wet ash.

3. Washing and desalination treatment of municipal waste incineration ash (1) Washing and desalination treatment (without pH adjustment, reference example 1)
The slurry (1) was prepared by adding 5 times the amount of water (1) to the wet mass of wet ash and stirring to prepare a slurry (1), followed by stirring and washing for 1 hour. Thereafter, a polymer flocculant (MT aquapolymer Co., Ltd., Akofloc A-110) was added and allowed to stand for 30 minutes, and solid-liquid separation was performed into a concentrated slurry (1 ') and a supernatant water (1). Next, the concentrated slurry (1 ′) was suction-filtered with 5A filter paper to separate solid and liquid into a dewatered cake (2 ′) and a filtrate (2 ′). After adding 5 times the amount of water (3) to the dehydrated cake (2 ') with respect to the wet mass of the wet ash and stirring to prepare a slurry (3'), stirring for 1 hour is followed by polymer aggregation An agent (MT aquapolymer Co., Ltd., Akofloc A-110) was added and allowed to stand for 30 minutes to perform solid-liquid separation into concentrated slurry (3 ') and supernatant water (3').
Next, the concentrated slurry (3 ′) was suction-filtered through 5 A filter paper, and solid-liquid separation was performed to a dewatered cake (4 ′) and a filtrate (4 ′). After drying the dehydrated cake (4 ') at 105 ° C for 24 hours, the chlorine content is in accordance with JIS R 5202 "Method for chemical analysis of cement" in the same way as incinerated ash, and the dioxin content is Notification No. It was measured in accordance with “Verification method of standards for general waste and special management industrial waste”. The results are shown in Table 2.
The supernatant water (1) has a pH, total chromium, zinc and cadmium concentrations in accordance with JIS K 0102 "Plant drainage test method", SS (mass of suspended solids) is in accordance with Environment Agency Notification No. 59, and dioxin concentration is It measured based on JISK0312 "the measuring method of dioxins in industrial water and factory drainage." The results are shown in Table 3.

(2) Washing and desalting treatment (pH adjusted, pH = 10.5, 11.5, Examples 1 and 2)
A slurry (1) is prepared by adding 5 times the amount of water (1) to the wet mass of the wet ash and stirring to prepare a slurry (1), then hydrochloric acid is added to adjust the pH of the slurry (1) to 10.5 or 11.5. Stir wash was performed for 1 hour while maintaining. Thereafter, a polymer flocculant (MT aquapolymer Co., Ltd., Akofloc A-110) was added and allowed to stand for 30 minutes, and solid-liquid separation was performed into a concentrated slurry (1) and a supernatant water (1). Next, the concentrated slurry (1) was suction-filtered through 5A filter paper to separate solid and liquid into a dewatered cake (2) and a filtrate (2). After adding 5 times the amount of water (3) to the dehydrated cake (2) with respect to the wet mass of wet ash and stirring to prepare a slurry (3), a polymer flocculating agent MT Aquapolymer Co., Ltd., Akofloc A-110) was added and allowed to stand for 30 minutes, and solid-liquid separation was performed into a concentrated slurry (3) and a supernatant water (3). Next, the concentrated slurry (3) was suction-filtered with 5A filter paper to separate solid-liquid into a dewatered cake (4) and a filtrate (4). The chlorine content, dioxin content, and pH of the supernatant water (1), the total chromium, zinc, cadmium concentration, SS, and dioxin concentration of the dehydrated cake (4) were measured. The results are shown in Table 2 and Table 3, respectively.

(3) Water-washing desalting treatment (with pH adjustment, pH = 9, 10, Comparative examples 1 to 2)
In Comparative Examples 1 and 2, tests were conducted in the same manner as in Examples 1 and 2 except that washing was carried out with stirring for 1 hour while maintaining the pH of the slurry (1) at 9 or 10. The chlorine content, dioxin content, and pH of the supernatant water (1), the total chromium, zinc, cadmium concentration, SS, and dioxin concentration of the dehydrated cake (4) were measured. The results are shown in Table 2 and Table 3, respectively.

(4) Evaluation From Table 2, the desalting rate is as high as 95% or more in all of Reference Example 1, Example 1, Example 2, Comparative Example 1 and Comparative Example 2, and the slurry (1) at the time of washing was The influence of pH was small. On the other hand, according to Reference Example 1, Example 2 and Comparative Example 2, the lower the pH, the higher the dioxin concentration in the dehydrated cake. Therefore, it was found that dioxins insoluble in acid tend to be concentrated in the dewatered cake even though the desalting rate does not change so much when the pH is lowered by adding hydrochloric acid.

  From Table 3, in the case of no pH adjustment in Reference Example 1, the supernatant water (1) contained 1.9 pg-TEQ / L of dioxin. Also, the SS increased as the pH was lowered by adding an acid. In general, dioxins in waste water exist in a state of being adsorbed to SS, so it is considered that the dioxin concentration in the supernatant water (1) becomes higher as the pH is lowered by adding an acid.

4. Waste water treatment of supernatant water (1) (1) Properties of supernatant water (1) The supernatant water (1) is washed with water by the same operation as Reference Example 1 in Table 3 using newly prepared wet ash. Was performed, and used what was collected. The properties of the used supernatant water (1) are shown in Table 4.

(2) Waste water treatment method Hydrochloric acid was added to supernatant water (1) (pH 12.5) having the properties shown in Table 4 to adjust to pH 2, sodium bisulfite was added as a reducing agent, and the mixture was stirred for 15 minutes. Next, ferric chloride was added as an inorganic coagulant, sodium hydroxide or calcium hydroxide was added as a pH adjuster to adjust to pH 10, and the mixture was allowed to stand for 15 minutes, and then supernatant water (6) was collected. The supernatant water (6) is all chromium, hexavalent chromium, zinc, cadmium concentration in accordance with JIS K 0102 "Factory drainage test method", SS is in accordance with Environment Agency Notification No. 59, and the dioxin concentration is JIS K 0312 " It measured according to "the measuring method of dioxins in industrial water and factory drainage". The precipitate remaining after collecting the supernatant water (6) was suction filtered with 5 A filter paper, dried at 105 ° C. for 12 hours, and weighed. The amount of dioxin adsorption to the sediment was calculated by equation (1), and the dioxin removal rate was calculated by equation (2).

ここで、Ｃ_１は上澄み水（１）のダイオキシン濃度（pg-TEQ/L）、Ｃ_２は上澄み水（６）のダイオキシン濃度（pg-TEQ/L）、Ｍは沈殿物量（g/L）である。結果を表５に示す。

Here, C ₁ is the dioxin concentration (pg-TEQ / L) of the supernatant water (1), C ₂ is the dioxin concentration of the supernatant water (6) (pg-TEQ / L), and M is the amount of precipitate (g / L) It is. The results are shown in Table 5.

From Example 3 and Comparative Example 3 in Table 5, by using sodium hydroxide having a high pH adjustment rate as a pH adjuster, it is possible to reduce SS generated in the aggregation precipitation process, and the dioxin adsorption amount to the precipitate increases. The dioxin removal rate has increased.
Therefore, according to the method of the present invention, if solid-liquid separation is performed on the supernatant water (6) as in the third embodiment of the flow of FIG. Can be removed. In addition, since dioxins are concentrated in the solid phase, dioxins can be instantaneously decomposed, so that they can be put into a calciner or mixed with other cement materials and used after dilution.

Claims (11)

Water (1) is added to the incinerator ash and stirred and washed to prepare a slurry (1), and then the acid (1) is added to adjust the pH to 10.5 to 12.5, and after addition of a polymer flocculant, A first step of standing still and solid-liquid separation into concentrated slurry (1) and supernatant water (1);
A second step of filtering the concentrated slurry (1) and separating it into a dewatered cake (2) and a filtrate (2);
Water (3) is added to the above dewatered cake (2) and stirred and washed to prepare a slurry (3), and then a polymer flocculant is added and allowed to stand to form concentrated slurry (3) and supernatant water (3). A third step of solid-liquid separation,
A fourth step of filtering the concentrated slurry (3) and performing solid-liquid separation into a dehydrated cake (4) and a filtrate (4);
A cement raw material forming step including the fifth step of using the dewatered cake (4) as a cement raw material;
Acid (6) is added to the supernatant water (1) and stirred, pH is adjusted to 1 to 3 and a reducing agent is added, and further an inorganic flocculant is added, sodium hydroxide is added and the pH is adjusted The waste water treatment process which has the 6th process of carrying out solid-liquid separation to a sediment and supernatant water (6) after adjusting to 8-11 and leaving still,
A method of treating incineration ash comprising:   The method for treating incineration ash according to claim 1, wherein the water content of the incineration ash is more than 0% by mass and not more than 30% by mass.   The method for treating incineration ash according to claim 1 or 2, wherein the acid (1) in the first step is one or more selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid.   The method for treating incineration ash according to any one of claims 1 to 3, wherein the acid (6) in the sixth step is one or more selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid.   The incineration according to any one of claims 1 to 4, wherein the reducing agent in the sixth step is one or more selected from the group consisting of sodium bisulfite, sodium sulfite, ferrous chloride and ferrous sulfate. Ash processing method.   The incinerator according to any one of claims 1 to 5, wherein the inorganic coagulant in the sixth step is one or more selected from the group consisting of ferric chloride, ferric sulfate and polyferric sulfate. Ash processing method.   The method for treating incineration ash according to any one of claims 1 to 6, wherein the amount of water (1) added in the first step is 1 to 10 times the amount of incineration ash.   The method for treating incineration ash according to any one of claims 1 to 7, wherein the amount of water (3) added in the third step is 1 to 10 times the amount of incineration ash.   The method according to any one of claims 1 to 8, wherein the first step further comprises a seventh step of adding water (7) to dry ash to prepare the incineration ash.   The method for treating incinerated ash according to claim 9, wherein the dioxin content of the dry ash is 3 ng-TEQ / g or less based on the dry mass of the dry ash. The chemical components of the dry ash have an SiO ₂ content of 1 to 10 mass%, an Al ₂ O ₃ content of 1 to 8 mass%, and an Fe ₂ O ₃ content of 0. 1 based on the dry mass of the dry ash. 1-2 mass%, CaO content 20-50 mass%, MgO content 0.5-3.0 mass%, SO ₃ content 1.0-5.0 mass%, Cl content 10 To 30% by mass, Cr content is 0.03 to 0.1% by mass, Pb content is 0.05 to 0.2% by mass, Zn content is 0.2 to 0.5% by mass and Cd content The method for treating incineration ash according to claim 9 or 10, wherein is 0.003 to 0.01% by mass.

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