JP2017189775A - Municipal refuse treatment system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a municipal refuse treatment system by which the fly ash of a municipal refuse incinerator and a melting furnace is perfectly reutilized.SOLUTION: In a municipal refuse treatment system 1 which comprises an incinerator 2 incinerating municipal refuse W, a washing desalination facility 3 washing and desalinating fly ash FA generated in the incinerator and a melting furnace 4 melting fly ash WA after desalination by the washing desalination facility and where molten fly ash MA generated in the melting furnace is washed and desalinated by the washing desalination facility and a part WM 2 of the molten fly ash after desalination is returned to the melting furnace,: a valuable metal recovery facility (HMX facility) 5 recovering valuable metals from the molten fly ash generated in the melting furnace is disposed and residue LR after treatment by the valuable metal recovery facility may be returned to the melting furnace; a melting furnace melting the municipal refuse and a washing desalination facility washing and desalinating the molten fly ash generated in the melting furnace are disposed and a part of the molten fly ash after desalination may be returned to the melting furnace; and a melting furnace melting the municipal refuse and a valuable metal recovery facility recovering valuable metals from the molten fly ash generated in the melting furnace are disposed and the residue after treatment by the valuable metal recovery facility may be returned to the melting furnace.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a system for treating municipal waste.

  In recent years, the amount of waste such as municipal waste incineration ash contained in the final disposal site is approaching the maximum capacity of the final disposal site, so reducing the amount of waste has become an urgent issue. . One way to reduce the amount of waste is to recycle municipal waste. For example, of the municipal waste incineration ash generated in large quantities, the main ash is used as a raw material for cement after a predetermined treatment.

  On the other hand, fly ash in municipal waste incinerators and melting furnaces is not only used as a raw material for cement but also contains a lot of valuable metals, so technologies for recovering valuable metals such as copper, zinc and lead from fly ash have been developed ( Patent Document 1).

JP 2007-186761 A

  However, a large amount of fly ash from municipal waste incinerators and melting furnaces is still being disposed of in landfills, and as mentioned above, the capacity of landfill sites is tight, so reduction of the amount of disposal is required. ing.

  Then, this invention is made | formed in view of the problem in the said prior art, Comprising: It aims at completely reusing the fly ash of a municipal waste incinerator or a melting furnace.

  In order to achieve the above object, the present invention is a municipal waste treatment system, an incinerator for incinerating municipal waste, and a water washing and desalination facility for desalinating the fly ash generated in the incinerator by washing with water. And a melting furnace for melting fly ash after desalting by the water washing and desalting equipment, and the molten fly ash generated in the melting furnace is washed by the water washing and desalting equipment and desalted, and after desalting A part of the molten fly ash is returned to the melting furnace.

  According to the present invention, municipal waste fly ash can be melted and reused as slag. In addition, since municipal waste incineration fly ash and fly ash generated in the melting furnace are washed with water and returned to the melting furnace, the load on the melting furnace due to an increase in chlorine can be reduced. Furthermore, since a part of the fly ash generated in the melting furnace is returned to the melting furnace, the concentration of valuable metals can be increased, and a refining raw material that is profitable can be obtained. Moreover, since some molten fly ash is discharged | emitted out of a system as a smelting raw material, it is suppressed that the density | concentration of harmful metals, such as lead in slag, increases, and the elution can be prevented. Therefore, all municipal waste is finally reused without being disposed of in landfills.

  The present invention also relates to a municipal waste treatment system, an incinerator for incinerating municipal waste, a water washing and desalination facility for washing and desalting the fly ash generated in the incinerator, and the water washing and dewatering. A melting furnace for melting fly ash after desalting by a salt facility, and a valuable metal recovery facility for recovering valuable metals from the molten fly ash generated in the melting furnace, and a residue after processing by the valuable metal recovery facility It returns to the said melting furnace, It is characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, the smelting raw material which further raised the density | concentration of the valuable metal in molten fly ash can be obtained by using the valuable metal recovery equipment which collects a valuable metal. Moreover, since the circulation of chlorine and harmful metals is reduced, the load on the melting furnace is further reduced, and the possibility of leaching of harmful metals such as lead from the slag is lowered.

  Further, the present invention is a municipal waste treatment system comprising a melting furnace for melting municipal waste, and a water washing and desalination facility for washing and desalting the molten fly ash generated in the melting furnace, A part of the molten fly ash after desalting is returned to the melting furnace.

  According to the present invention, a part of the molten fly ash after desalting is returned to the melting furnace and melted again, whereby the concentration of valuable metals can be increased, and a refining raw material that can be profitable can be obtained. Since some molten fly ash is discharged out of the system as a smelting raw material, an increase in the concentration of harmful metals such as lead in the slag is suppressed, and elution can be prevented.

  Further, the present invention is a municipal waste treatment system, comprising a melting furnace for melting municipal waste, and a valuable metal recovery facility for recovering valuable metal from molten fly ash generated in the melting furnace, the valuable metal The residue after the treatment by the recovery facility is returned to the melting furnace.

  According to the present invention, the concentration of valuable metals in the molten fly ash can be further increased, and the circulation of chlorine and harmful metals is reduced, so that the load on the melting furnace is further reduced, and slag, lead, etc. The possibility of toxic metal elution is reduced.

  In the municipal waste treatment system, the valuable metal may contain at least lead.

  In addition, the use of lime for waste gas treatment in the melting furnace increases the concentration of alkaline earth metals such as calcium in the generated molten fly ash. By returning this, the melting temperature is lowered and the amount of energy used is reduced. be able to.

  In the municipal waste treatment system, seawater can be used as at least a part of the washing water in the washing and desalination facility. Thereby, valuable metals can be chlorinated and volatilized in the molten fly ash.

  As described above, according to the present invention, fly ash from municipal waste incinerators and melting furnaces can be reused as construction materials such as roadbed materials and aggregates as slag. Furthermore, since municipal waste can be processed while increasing the concentration of valuable metals, it can be reused as a refining raw material for valuable metals.

1 is an overall configuration diagram illustrating a municipal waste disposal system according to a first embodiment of the present invention. It is a whole block diagram which shows the processing system of the municipal waste which concerns on 2nd Embodiment of this invention. It is a flowchart for demonstrating the HMX processing equipment of the municipal waste processing system of FIG. It is a whole block diagram which shows the processing system of the municipal waste which concerns on 3rd Embodiment of this invention. It is a whole block diagram which shows the disposal system of the municipal waste which concerns on 4th Embodiment of this invention.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a municipal waste treatment system 1 according to a first embodiment of the present invention. This treatment system 1 is an incinerator 2 for incinerating municipal waste W, and water ash FA generated in the incinerator 2 is washed with water. The water washing and desalination equipment 3 for desalting and the melting furnace 4 for melting the fly ash WA after desalting by the water washing and desalination equipment 3 are provided.

  The incinerator 2 can be an incinerator such as a stalker type incinerator, a fluidized bed incinerator, or a rotary kiln. Municipal waste W is incinerated by the incinerator 2, fly ash FA and main ash (not shown) are generated, and the fly ash FA is sent to the water washing and desalination facility 3.

  The water washing and desalination equipment 3 is provided for washing and desalting the fly ash FA generated in the incinerator 2, and a slurrying device (not shown) for adding water and warm water to the fly ash FA to make a slurry. And a solid-liquid separation device (not shown) such as a belt filter that separates solid-liquid while washing the slurry generated by the slurrying device.

  The melting furnace 4 is provided to melt the fly ash (water washing residue) WA desalted by the water washing and desalination equipment 3 at a high temperature to generate slag SL. As the melting furnace 4, a gasification melting furnace such as a shaft type, a surface melting type, a gas reforming type, and a kiln type, and a melting furnace such as an electric resistance type, a surface melting type, and a plasma type can be used.

  Next, the municipal waste W processing method using the processing system 1 having the above-described configuration will be described.

  The received municipal waste W is put into the incinerator 2 and incinerated. As a result, fly ash FA and main ash are generated. The fly ash FA is supplied to the water washing and desalination facility 3 and washed with water to remove water-soluble chlorine, and the main ash is separately recycled as a cement raw material or the like.

  The fly ash WA desalted by the water washing and desalting equipment 3 is charged into the melting furnace 4 to melt the fly ash WA. Thereby, slag SL and molten fly ash MA are generated. The slag SL is used as a construction material such as a roadbed material or an aggregate. On the other hand, the molten fly ash MA is supplied to the water washing and desalting equipment 3 and washed and desalted, and the valuable metal is recovered using the molten fly ash WM1 after the desalting as a smelting raw material. Smelting slag generated during smelting is also used as construction material such as roadbed materials.

  Further, in order to recover valuable metal with a high concentration, a part of the molten fly ash WM1 (molten fly ash MW2) after desalting is returned to the melting furnace 4 and melted again together with the fly ash FA. Thereby, the density | concentration of the valuable metals in molten fly ash MA and the molten fly ash WM1 after desalting can be raised, and collection | recovery of valuable metals, such as lead, can be made easy in a back | latter stage. Here, the amount of the molten fly ash MW2 is adjusted so as to be within a concentration at which no harmful components are eluted from the slag SL. Further, in the melting furnace 4 that uses lime for waste gas treatment, since the alkaline earth metal concentration such as calcium of the resulting molten fly ash MA is high, the melting temperature is lowered by returning this, and the amount of energy used Can be reduced.

  In addition, seawater can also be used for the water used when slurrying fly ash FA other than fresh water (engineering water). Slurry fly ash FA with seawater and wash and desalinate to reduce the amount of industrial water used, and volatilize valuable metals in fly ash WA after desalting in the subsequent melting furnace 4. Thus, the recovery efficiency of valuable metals can be increased.

  Even when using industrial water, the amount of industrial water used for washing can be reduced so that chlorine remains in the incineration fly ash residue, and metals can be chlorinated and volatilized in the molten fly ash. This also applies to processing systems 10, 20, and 30 according to other embodiments described later.

  As described above, according to the municipal waste treatment system 1 according to the first embodiment, the incinerator 2 and the melting furnace are increased while increasing the concentration of valuable metals in the molten fly ash MA and the molten fly ash WM1 after desalting. The fly ash generated in 4 can also be completely reused.

  Next, a second embodiment of the present invention will be described with reference to FIG. This treatment system 10 includes an incinerator 2 that incinerates municipal waste W, a water washing and desalination facility 3 that rinses and demineralizes fly ash FA generated in the incinerator 2, and a desalination by the water washing and desalination facility 3 It comprises a melting furnace 4 for melting the later fly ash WA, and an HMX facility (valuable material recovery facility) 5 for recovering valuable metals from the molten fly ash MA generated in the melting furnace 4.

  The same thing as 1st Embodiment mentioned above can be used for the incinerator 2, the water washing desalination equipment 3, and the melting furnace 4. FIG.

  The HMX facility 5 is a facility for recovering valuable metals such as copper, zinc, iron, lead and the like from the molten fly ash MA by a flow described later, and specifically includes a water washing treatment device, a leaching tank, a precipitation tank, and the like. In the present invention, as an HMX facility, a facility capable of recovering at least lead, such as the method described in Patent Document 1 and Japanese Unexamined Patent Application Publication No. 2012-167332, may be used.

  Next, a method for processing municipal waste W by the processing system 10 having the above-described configuration will be described.

  The received municipal waste W is put into the incinerator 2 and incinerated. As a result, fly ash FA and main ash are generated. The fly ash FA is supplied to the water washing and desalination facility 3 and washed with water to remove water-soluble chlorine, and the main ash is separately recycled as a cement raw material or the like.

  The fly ash WA desalted by the water washing and desalting equipment 3 is charged into the melting furnace 4 to melt the fly ash WA. Thereby, slag SL and molten fly ash MA are generated. The slag SL is used as a construction material such as a roadbed material or an aggregate. On the other hand, the molten fly ash MA is supplied to the HMX facility 5.

  Next, as shown in FIG. 3, in the HMX equipment 5, first, water is added to the molten fly ash MA to form a slurry, followed by washing with water (step S1). As a result, water-soluble chlorine and the like are removed, and the generated chlorine-containing wastewater is treated separately.

  Sulfuric acid is added to the slurry containing the molten fly ash WM1 after washing (step S2), and the slurry to which sulfuric acid has been added branches into two systems.

  In one system, iron is added to the slurry 1 to perform cementation (step S3). The cementation is a reaction in which a metal ion having a noble reduction potential existing in an aqueous solution is reduced and precipitated by a metal having a low reduction potential due to a difference in redox potential. By adding metallic iron, copper ions having a reduction potential nobler than iron are substituted and deposited on the surface of iron. And the metallic iron which copper precipitated is isolate | separated and removed from an acid leaching solution using a well-known solid-liquid separation means. Furthermore, pH adjustment is performed to precipitate iron hydroxide and zinc hydroxide (step S4).

  In the other system, caustic soda is added to the slurry 2 and alkali leaching is performed (step S5). In the alkaline leaching, the leaching residue is calcium starch (calcium hydroxide), while the leaching solution is subjected to sulfide precipitation, and lead sulfide is generated (step S6).

  As described above, the smelting raw material M (see FIG. 2) in which valuable metals such as copper, zinc, iron, lead and the like have a high concentration is recovered from the municipal waste W.

  On the other hand, the calcium starch as the leaching residue LR is mainly composed of inorganic components other than valuable metals, and is returned to the melting furnace 4 to be melted. Here, since harmful components such as lead hardly return to the melting furnace 4, no harmful metals such as lead are eluted from the slag SL. Further, in the melting furnace 4 that uses lime for waste gas treatment, the alkaline earth metal concentration of the leaching residue LR is high because the alkaline earth metal concentration such as calcium of the generated molten fly ash MA is high. Therefore, by returning this to the melting furnace 4, the melting temperature is lowered and the amount of energy used can be reduced.

  As described above, according to the municipal waste treatment system 10 according to the second embodiment, the incinerator 2 and the melting furnace are increased while increasing the concentration of valuable metals in the molten fly ash MA and the molten fly ash WM1 after desalting. The fly ash generated in 4 can also be completely reused.

  Next, a third embodiment of the present invention will be described. FIG. 4 is an overall configuration diagram showing a municipal waste disposal system 20 according to the third embodiment of the present invention. Unlike the processing system 1 which concerns on 1st Embodiment mentioned above, or the processing system 10 which concerns on 2nd Embodiment, this processing system 20 is supplied to the melting furnace 4 directly without municipal waste W passing through an incinerator. .

  The processing system 20 according to the third embodiment includes a melting furnace 4 and a water washing and desalting facility 3. The melting furnace 4 and the water washing and desalting facility 3 are the same as those according to the above-described embodiments.

  Next, a method for processing municipal waste W by the processing system 20 having the above-described configuration will be described.

  The accepted municipal waste W is put into the melting furnace 4 to melt the municipal waste W. Thereby, molten fly ash MA and slag SL are produced. The slag SL is used as a construction material such as a roadbed material or an aggregate. On the other hand, the molten fly ash MA is supplied to the water washing and desalting facility 3.

  The molten fly ash MA charged into the water washing and desalting facility 3 is washed with water to remove water-soluble chlorine. Since the molten fly ash WM1 after desalting contains abundant valuable metals such as lead, the valuable metal is recovered using the molten fly ash WM1 after desalting as a smelting raw material.

  Further, a part of the molten fly ash WM1 after desalting (molten fly ash WM2) is returned to the melting furnace 4 in order to recover a high-concentration valuable metal. Thereby, the density | concentration of the valuable metal in molten fly ash MA and the molten fly ash WM1 after desalting can be made high.

  As described above, the processing system 20 according to the third embodiment also increases the concentration of valuable metals in the molten fly ash MA and the molten fly ash WM1 after desalting, while the fly ash generated in the melting furnace 4 is also increased. Can be completely reused.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. The municipal waste treatment system 30 according to the present embodiment collects valuable metals from the molten fly ash MA using the HMX equipment 5 instead of the water washing and desalination equipment 3 in the treatment system 20 according to the third embodiment described above. To do. The melting furnace 4 and the HMX facility 5 are the same as those according to the above-described embodiments.

  A method for processing municipal waste W by the processing system 30 having the above configuration will be described.

  The accepted municipal waste W is put into the melting furnace 4 to melt the municipal waste W. Thereby, molten fly ash MA and slag SL are produced. The slag SL is used as a construction material such as a roadbed material or an aggregate. On the other hand, the molten fly ash MA is supplied to the HMX facility 5.

  Next, in the HMX facility 5, the above-described process shown in FIG. 3 is performed, and the smelting raw material M in which valuable metals such as copper, zinc, iron, lead, etc. are concentrated from the municipal waste W is recovered and leached. The calcium starch as the residue LR is returned to the melting furnace 4 and melted.

  As described above, according to the municipal waste treatment system 30 according to the fourth embodiment, the fly ash generated in the melting furnace 4 is completely reused while increasing the concentration of valuable metals in the molten fly ash MA. be able to.

  In the above embodiment, the fly ash of municipal waste and the municipal waste are each melted in the melting furnace 4, but the fly ash of municipal waste and the municipal waste may be melted simultaneously in the melting furnace 4.

1, 10, 20, 30 Municipal waste treatment system 2 Incinerator 3 Flushing desalination equipment 4 Melting furnace 5 HMX equipment FA Fly ash LR Leaching residue M Smelting raw material MA Molten fly ash SL Slag W Municipal waste WA Desalted Fly ash WM1, WM2 Desalted molten fly ash

Claims (7)

An incinerator for incinerating municipal waste;
A water washing and desalting facility for washing and desalting the fly ash generated in the incinerator;
A melting furnace for melting fly ash after desalting by the water washing and desalting equipment,
A municipal waste treatment system characterized in that the molten fly ash generated in the melting furnace is washed with the water washing and desalting equipment to desalinate, and a part of the molten fly ash after desalting is returned to the melting furnace. . An incinerator for incinerating municipal waste;
A water washing and desalting facility for washing and desalting the fly ash generated in the incinerator;
A melting furnace for melting fly ash after desalting by the water washing and desalting facility;
A valuable metal recovery facility for recovering valuable metals from the molten fly ash generated in the melting furnace,
A municipal waste treatment system, wherein residues after treatment by the valuable metal recovery facility are returned to the melting furnace. A melting furnace for melting municipal waste,
A water washing and desalting facility for washing and desalting the molten fly ash generated in the melting furnace,
A municipal waste treatment system, wherein part of the molten fly ash after desalting is returned to the melting furnace. A melting furnace for melting municipal waste,
A valuable metal recovery facility for recovering valuable metals from the molten fly ash generated in the melting furnace,
A municipal waste treatment system, wherein residues after treatment by the valuable metal recovery facility are returned to the melting furnace.   The municipal waste disposal system according to any one of claims 1 to 4, wherein the valuable metal contains at least lead.   6. The municipal waste treatment system according to claim 1, wherein the melting furnace uses lime for waste gas treatment.   The municipal waste treatment system according to any one of claims 1 to 6, wherein seawater is used as at least a part of the washing water in the water washing and desalination facility.

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