JPH0924240A - Method for recovering heavy metals from exhaust gas generated when bottom ash and fly ash are melted - Google Patents

Method for recovering heavy metals from exhaust gas generated when bottom ash and fly ash are melted

Info

Publication number
JPH0924240A
JPH0924240A JP17772795A JP17772795A JPH0924240A JP H0924240 A JPH0924240 A JP H0924240A JP 17772795 A JP17772795 A JP 17772795A JP 17772795 A JP17772795 A JP 17772795A JP H0924240 A JPH0924240 A JP H0924240A
Authority
JP
Japan
Prior art keywords
heavy metals
exhaust gas
fly ash
cleaning
ash
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP17772795A
Other languages
Japanese (ja)
Other versions
JP3009607B2 (en
Inventor
Hiroaki Kawabata
博昭 河端
Shiyoumasa Chichibu
蕉雅 秩父
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kobe Steel Ltd
Original Assignee
Kobe Steel Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kobe Steel Ltd filed Critical Kobe Steel Ltd
Priority to JP17772795A priority Critical patent/JP3009607B2/en
Publication of JPH0924240A publication Critical patent/JPH0924240A/en
Application granted granted Critical
Publication of JP3009607B2 publication Critical patent/JP3009607B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/20Recycling

Landscapes

  • Treating Waste Gases (AREA)
  • Processing Of Solid Wastes (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Gasification And Melting Of Waste (AREA)

Abstract

PROBLEM TO BE SOLVED: To recover heavy metals inexpensively and easily recyclably from fly ash in exhaust gas generated when bottom ash and fly ash are melted. SOLUTION: An exhaust gas contg. fly ash generated when bottom ash and fly ash are melted is introduced into a wet scrubber and the fly ash and evaporated heavy metals caught by cleaning in the wet scrubber 2 are inexpensively dissolved with a post-cleaning drain water contg. hydrochloric acid generated by cleaning. NaHS or Na2 S and NaOH are added to this drain water to adjust pH to lower than 0.4 and the heavy metals contg. a large amount of Cu component are separated in the primary precipitation tank 3 and they are filtered. Then, the filtered water is sent into the secondary precipitation tank 5 and pH is adjusted to at least 0.4 and heavy metals contg. a large amount of (Pb+Zn) components are separated and filtered to obtain the primary recovered matter contg. a large amount of easily recyclable Cu component and the secondary recovered matter contg. a large amount of the (Pb+Zn) components.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【発明の属する技術分野】本発明は、都市ごみや産業廃
棄物などの焼却により生じる焼却灰や飛灰を減容化、安
定化のために溶融するに際して生じる排ガスに含まれて
いる重金属類を、鉱酸等を用いるまでもなく溶解し、リ
サイクルし易いように分別回収することを可能ならしめ
るようにした焼却灰や飛灰の溶融に際して生じる排ガス
からの重金属類の回収方法に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to reducing heavy metals contained in exhaust gas generated when melting incineration ash or fly ash generated by incineration of municipal waste, industrial waste, etc. for melting and stabilization. The present invention relates to a method for recovering heavy metals from exhaust gas generated when melting incinerated ash or fly ash, which is dissolved without using mineral acid or the like and can be separated and recovered so as to be easily recycled.

【0002】[0002]

【従来の技術】周知のように、都市ごみや産業廃棄物等
は都市ごみ焼却場に集積されて焼却処理されているが、
焼却で発生する焼却灰や飛灰は最終処分場に堆積されて
いた。ところが、近年、堆積場確保の困難性や焼却灰や
飛灰に含まれている水銀、銅、鉛、クロム、カドミウム
等の重金属類やダイオキシン類等の有害物質が流出する
という環境汚染問題が重要視されるようになり、焼却灰
や飛灰を溶融炉や高温加熱炉で溶融し、スラグ化するこ
とにより減容化、安定化処理されるようになってきてい
る。しかしながら、溶融炉や高温加熱炉により焼却灰や
飛灰を溶融処理するに際しても、溶融炉や高温加熱炉か
ら上記のような種々の重金属類を含む飛灰を含む排ガス
が発生するので、この排ガス中に含まれている重金属類
を確実に、かつリサイクルし得るように分別回収するこ
とが、環境汚染防止や重金属類の有効活用にとって好ま
しい。
2. Description of the Related Art As is well known, although municipal solid waste and industrial waste are collected and incinerated at municipal solid waste incinerators,
Incinerated ash and fly ash generated by incineration were accumulated at the final disposal site. However, in recent years, it is important to secure a deposit site and environmental pollution problems such as heavy metals such as mercury, copper, lead, chromium and cadmium contained in incineration ash and fly ash and harmful substances such as dioxins are flowing out. As a result, incineration ash and fly ash are melted in a melting furnace or a high-temperature heating furnace and turned into slag to be reduced in volume and stabilized. However, even when incinerating ash or fly ash in a melting furnace or a high-temperature heating furnace, exhaust gas containing fly ash containing various heavy metals as described above is generated from the melting furnace or the high-temperature heating furnace. It is preferable to separate and collect the heavy metals contained therein so that they can be recycled reliably and for the purpose of preventing environmental pollution and effectively utilizing the heavy metals.

【0003】重金属類を含む排ガスを処理するものとし
ては、例えば特公昭61−16494号公報に開示され
てなる「重金属含有排ガスの洗浄処理法」が知られてい
る。以下、この「重金属含有排ガスの洗浄処理法」の概
要を説明すると、重金属を含有する酸性燃焼排ガスを水
酸化マグネシウムおよび/または軽焼マグネシアを吸収
剤とする洗浄水で洗浄する。洗浄により生じた洗浄廃水
に第一鉄イオンを加え、アルカリでpHを6〜7に調整
した後に、さらに硫黄イオン源を加えてアルカリでpH
を7〜8に調整する。このpH調整により生じた不溶性
沈澱物を除去することにより、重金属を除去するもので
ある。
As a method for treating exhaust gas containing heavy metals, for example, a "cleaning method for exhaust gas containing heavy metals" disclosed in Japanese Patent Publication No. 61-16494 is known. Hereinafter, the outline of the "cleaning method for heavy metal-containing exhaust gas" will be described. The acidic combustion exhaust gas containing heavy metal is cleaned with cleaning water containing magnesium hydroxide and / or light burned magnesia as an absorbent. Ferrous ions are added to the washing wastewater generated by washing, and the pH is adjusted to 6 to 7 with alkali, and then a sulfur ion source is further added to adjust the pH with alkali.
Is adjusted to 7-8. Heavy metals are removed by removing the insoluble precipitate generated by this pH adjustment.

【0004】また、特開平6−170354号公報に
は、「焼却炉や溶融炉からの飛灰の処理方法」が開示さ
れている。これは、焼却炉や溶融炉から発生するナトリ
ウムおよびカリウム、並びに亜鉛、銅および鉛等の重金
属を含む飛灰をそのまままたは鉱酸を添加してpH3以
下で溶解することにより鉛以外の重金属を溶出させる。
さらに、鉛を含む残渣を濾別する第一工程において得ら
れた濾液に中和剤を添加して、pH7以上に中和して亜
鉛を主とする重金属の水酸化物を生成させる。そして、
必要に応じて亜鉛を主とする重金属の水酸化物を濾別し
た濾液に硫化剤を添加して残りの重金属を硫化物として
沈澱させ、これを濾別することにより重金属を除去する
ものである。
Further, Japanese Unexamined Patent Publication No. 6-170354 discloses "a method for treating fly ash from an incinerator or a melting furnace". This is to elute heavy metals other than lead by dissolving fly ash containing heavy metals such as sodium and potassium, zinc, copper and lead generated from incinerators and melting furnaces as it is or by adding mineral acid at pH 3 or less. Let
Further, a neutralizing agent is added to the filtrate obtained in the first step of separating the lead-containing residue by filtration to neutralize it to pH 7 or above to produce a heavy metal hydroxide mainly containing zinc. And
If necessary, a sulfidizing agent is added to the filtrate obtained by filtering out the hydroxides of heavy metals, mainly zinc, and the remaining heavy metals are precipitated as sulfides, and the heavy metals are removed by filtering. .

【0005】また、特開平6−170354号公報に
は、上記第一工程で得られた濾液に、過酸化水素水、次
亜塩酸ナトリウムおよび塩素ガスから選定した酸化剤を
添加し、濾液中に溶解している鉄を酸化した後中和剤を
添加することにより濾液をpH3〜5の範囲に中和して
鉄の水酸化物を生成させる。そして、この濾液を濾別す
る第二工程で得られた濾液に中和剤を添加してpH7以
上に中和し、亜鉛を主とする重金属の水酸化物を生成さ
せる。そして、必要に応じて亜鉛を主とする重金属の水
酸化物を濾別した濾液に硫化剤を添加して残りの重金属
を硫化物として沈澱させ、これを濾別することにより重
金属を除去する方法も開示している。
Further, in JP-A-6-170354, an oxidizing agent selected from hydrogen peroxide solution, sodium hypochlorite and chlorine gas is added to the filtrate obtained in the first step, and the filtrate is added to the filtrate. By oxidizing the dissolved iron and then adding a neutralizing agent, the filtrate is neutralized to a pH range of 3 to 5 to form iron hydroxide. Then, a neutralizing agent is added to the filtrate obtained in the second step of separating this filtrate by filtration to neutralize it to pH 7 or higher, and a hydroxide of a heavy metal mainly containing zinc is produced. Then, if necessary, a sulfidizing agent is added to a filtrate obtained by filtering out a hydroxide of a heavy metal mainly containing zinc to precipitate the remaining heavy metal as a sulfide, and a heavy metal is removed by filtering this. Also disclosed.

【0006】[0006]

【発明が解決しようとする課題】上記従来例に係る「重
金属含有排ガスの洗浄処理法」や「焼却炉や溶融炉から
の飛灰の処理方法」は重金属類除去という観点からすれ
ば、環境汚染防止上それなりに有用であるが、これらに
はそれぞれ下記の如き解決すべき課題がある。先ず、前
者の「重金属含有排ガスの洗浄処理法」では、資源のリ
サイクルという観点からすると、回収物の中に多種の重
金属が含まれているので、リサイクルのためにはさらな
る選別が必要であるから好ましくない。
The "cleaning method for exhaust gas containing heavy metals" and "processing method for fly ash from incinerators and melting furnaces" according to the above-mentioned conventional examples are environmental pollution from the viewpoint of removing heavy metals. Although useful as such for prevention, each of them has the following problems to be solved. First, from the viewpoint of resource recycling, the former “heavy metal-containing exhaust gas cleaning treatment method” contains a large number of heavy metals in the collected materials, so further sorting is necessary for recycling. Not preferable.

【0007】また、後者の「焼却炉や溶融炉からの飛灰
の処理方法」では、回収した飛灰に鉱酸等の溶解酸を添
加して溶解させるため、薬品代が必要で、飛灰の処理コ
ストが嵩み経済的に不利になる。勿論、鉱酸等の溶解酸
を添加せずにそのまま溶解させても良いとしているが、
鉱酸等の溶解酸を添加しない場合には飛灰の溶解率が低
く、鉛の回収が不充分になる結果、残渣の有害性をなく
することができない。
In the latter "method of treating fly ash from an incinerator or a melting furnace", a dissolved acid such as a mineral acid is added to the recovered fly ash to dissolve it, so that a chemical fee is required. However, the treatment cost is high, which is economically disadvantageous. Of course, it is said that it may be dissolved as it is without adding a dissolved acid such as mineral acid,
When a dissolved acid such as a mineral acid is not added, the fly ash has a low dissolution rate and lead recovery becomes insufficient, so that the harmfulness of the residue cannot be eliminated.

【0008】従って、本発明の目的とするところは、飛
灰を溶解させる鉱酸等の溶解用酸を添加することなく飛
灰中に含まれている重金属類を確実に捕集すると共に、
リサイクルし易いように、ある特定の重金属の含有量が
多い状態で分別回収することを可能ならしめる焼却灰や
飛灰の溶融に際して生じる排ガスからの重金属類の回収
方法を提供するにある。
Therefore, the object of the present invention is to reliably collect heavy metals contained in fly ash without adding a dissolving acid such as a mineral acid for dissolving fly ash, and
It is an object of the present invention to provide a method for recovering heavy metals from exhaust gas generated when incineration ash or fly ash is melted, which makes it possible to separate and recover a certain heavy metal in a high content state so that it can be easily recycled.

【0009】[0009]

【課題を解決するための手段】本発明は、上記実情に鑑
みてなされたものであって、従って上記課題を解決する
ために、本発明の請求項1に係る焼却灰や飛灰の溶融に
際して生じる排ガスからの重金属類の回収方法の要旨
は、溶融炉または高温加熱炉で焼却灰や飛灰等を溶融処
理するに際して発生する排ガスから重金属類を回収する
飛灰からの重金属類の回収方法において、前記排ガスを
湿式スクラバーにより洗浄し、洗浄後の排ガスを排ガス
処理装置に導入して処理する一方、洗浄により生じる洗
浄排水に水硫化ソーダまたは硫化ソーダ等の硫化物およ
び苛性ソーダ等のアルカリ剤を添加してpHを0.4未
満に調整し、このpH調整液から分離した分離物を濾過
すると共に、濾過水に順次前記硫化物とアルカリ剤とを
供給してpHを調整し、pH調整の都度分離する分離物
を濾過することによりそれぞれ特定の重金属類を多く含
む分離物を回収することを特徴とする。
The present invention has been made in view of the above circumstances, and therefore, in order to solve the above problems, when incinerating ash or fly ash according to claim 1 of the present invention is melted. The summary of the method for recovering heavy metals from exhaust gas generated is to recover heavy metals from exhaust gas generated when melting incineration ash or fly ash in a melting furnace or a high-temperature heating furnace in a method for recovering heavy metals from fly ash. While cleaning the exhaust gas with a wet scrubber and introducing the cleaned exhaust gas into an exhaust gas treatment device for processing, add sulfides such as sodium hydrosulfide or sodium sulfide and an alkali agent such as caustic soda to the cleaning wastewater generated by the cleaning The pH is adjusted to less than 0.4, and the separated substance separated from the pH adjusting liquid is filtered, and the sulfide and the alkaline agent are sequentially supplied to the filtered water to adjust the pH. , And recovering the isolate each containing many specific heavy metals by filtering the isolate to isolate each of the pH adjustment.

【0010】また、本発明の請求項2に係る焼却灰や飛
灰の溶融に際して生じる排ガスからの重金属類の回収方
法の要旨は、溶融炉または高温加熱炉で焼却灰や飛灰等
を溶融処理するに際して発生する排ガスから重金属類を
回収する飛灰からの重金属類の回収方法において、前記
排ガスを湿式スクラバーにより洗浄し、洗浄後の排ガス
を順次次段の湿式スクラバーにより洗浄し、最終段の湿
式スクラバーによる洗浄後の排ガスを排ガス処理装置に
導入して処理する一方、第一段の湿式スクラバーにおけ
る洗浄により生じる洗浄排水に水硫化ソーダまたは硫化
ソーダ等の硫化物および苛性ソーダ等のアルカリ剤を添
加してpHを0.4未満に調整し、このpH調整液から
分離した分離物を濾過すると共に、濾過水を次段の湿式
スクラバーに送り、この濾過水と次段の湿式スクラバー
による洗浄により生じる洗浄排水とに前記硫化物および
アルカリ剤を添加して、pHを予め設定した値に調整
し、これらpH調整液から分離した分離物を濾過すると
いうように、次段以降の湿式スクラバーにおける濾過水
と洗浄排水に対しても前記次段の湿式スクラバーにおけ
る濾過水と洗浄排水と同様の処理を行うことによりそれ
ぞれ特定の重金属類を多く含む分離物を回収することを
特徴とする。
Further, the gist of the method for recovering heavy metals from exhaust gas generated when melting incinerated ash or fly ash according to claim 2 of the present invention is to melt and treat incinerated ash or fly ash in a melting furnace or a high temperature heating furnace. In the method of recovering heavy metals from fly ash, which collects heavy metals from exhaust gas generated in the case of cleaning, the exhaust gas is washed with a wet scrubber, and the exhaust gas after cleaning is sequentially washed with a wet scrubber in the next stage, and the final stage is wet. Exhaust gas after cleaning with a scrubber is introduced into an exhaust gas treatment device for processing, while sulfides such as sodium hydrosulfide or sodium sulfide and an alkali agent such as caustic soda are added to the cleaning wastewater generated by the cleaning in the first-stage wet scrubber. Adjust the pH to less than 0.4, filter the separated substance separated from this pH-adjusted solution, and send the filtered water to the next stage wet scrubber. The sulfide and the alkaline agent are added to the filtered water and the cleaning wastewater generated by the subsequent cleaning with the wet scrubber to adjust the pH to a preset value, and the separated product separated from the pH adjusting liquid is filtered. As described above, the filtered water and the washing wastewater in the wet scrubber of the next stage and subsequent stages are also subjected to the same treatments as the filtered water and the washing drainage in the wet scrubber of the next stage, respectively, so that a separated substance containing a large amount of specific heavy metals is obtained. Is recovered.

【0011】また、本発明の請求項3に係る焼却灰や飛
灰の溶融に際して生じる排ガスからの重金属類の回収方
法の要旨は、請求項1または2に記載の焼却灰や飛灰の
溶融に際して生じる排ガスからの重金属類の回収方法に
おいて、溶融または高温加熱処理により発生する塩化物
の発生量が少ないときには、塩化物の発生量に応じて予
め前記焼却灰や飛灰等に塩素含有物を混入して溶融また
は高温加熱処理することを特徴とする。
The gist of the method for recovering heavy metals from exhaust gas produced during melting of incinerated ash or fly ash according to claim 3 of the present invention is the melting of incinerated ash or fly ash according to claim 1 or 2. In the method of recovering heavy metals from exhaust gas generated, when the amount of chloride generated by melting or high temperature heat treatment is small, chlorine-containing substances are mixed in advance with the incineration ash or fly ash according to the amount of chloride generated. It is characterized in that it is melted or heat-treated at a high temperature.

【0012】[0012]

【発明の実施の形態】焼却灰や飛灰に含まれている塩化
物に着目し、塩化物を含む焼却灰や飛灰の溶融により生
じる塩化物を洗浄水に溶解させれば塩酸になるので、焼
却灰や飛灰の溶融するに際して生じる排ガス中の飛灰や
揮散重金属塩類等を溶解することができ、鉱酸等の溶解
酸を用いる必要がなくなるので、重金属類の回収コスト
を低減することができる。また、洗浄水による急冷によ
り、排ガス中にガス化している揮散重金属塩類を洗浄水
により確実に捕捉することができる。特に、洗浄排水の
pHを0.4未満にすると銅硫化物の捕集分離効果が向
上し、さらに洗浄排水に硫化物を添加すると鉛、亜鉛等
の重金属類の捕集分離効果も向上する。従って、飛灰を
溶解させる鉱酸等の溶解用酸を特に添加するまでもなく
排ガス中に含まれている重金属類を確実に捕集すると共
に、リサイクルし易いように、ある特定の重金属の含有
量が多い状態で回収することが可能になると考え、溶融
炉または高温加熱炉で焼却灰や飛灰等を溶融処理するに
際して発生する排ガスから重金属類を回収する飛灰から
の重金属類の回収方法において、前記排ガスを湿式スク
ラバーにより洗浄し、洗浄後の排ガスを排ガス処理装置
に導入して処理する一方、洗浄により生じる洗浄排水に
水硫化ソーダまたは硫化ソーダ等の硫化物および苛性ソ
ーダ等のアルカリ剤を添加してpHを0.4未満に調整
し、このpH調整液から分離した分離物を濾過すると共
に、濾過水に順次前記硫化物とアルカリ剤とを供給して
pHを調整し、pH調整の都度分離する分離物を濾過す
ることによりそれぞれ特定の重金属類を多く含む分離物
を回収するようにしたものである。
BEST MODE FOR CARRYING OUT THE INVENTION Focusing on chlorides contained in incineration ash and fly ash, if chlorides produced by melting of incineration ash and fly ash containing chlorides are dissolved in washing water, it becomes hydrochloric acid. , It is possible to dissolve fly ash, volatile heavy metal salts, etc. in exhaust gas generated when incinerating ash and fly ash are melted, and it is not necessary to use dissolved acid such as mineral acid, so reducing the recovery cost of heavy metals You can Further, by quenching with the wash water, the volatile heavy metal salts gasified in the exhaust gas can be reliably captured by the wash water. In particular, when the pH of the cleaning waste water is less than 0.4, the effect of collecting and separating copper sulfide is improved, and when the sulfide is added to the cleaning waste water, the effect of collecting and separating heavy metals such as lead and zinc is also improved. Therefore, the heavy metal contained in the exhaust gas is reliably collected without adding a dissolving acid such as a mineral acid that dissolves fly ash, and the content of a specific heavy metal is included so that it can be easily recycled. We believe that it will be possible to recover large amounts of heavy metals, and a method for recovering heavy metals from fly ash that recovers heavy metals from exhaust gas generated when melting incineration ash or fly ash in a melting furnace or high-temperature heating furnace. In the above, while cleaning the exhaust gas with a wet scrubber and introducing the cleaned exhaust gas into an exhaust gas processing apparatus for processing, the cleaning wastewater generated by the cleaning is treated with a sulfide such as sodium hydrosulfide or sodium sulfide and an alkali agent such as caustic soda. The pH of the solution is adjusted to less than 0.4 by addition, the separated product separated from the pH-adjusted solution is filtered, and the sulfide and the alkaline agent are sequentially supplied to the filtered water to obtain p Adjust, is obtained so as to recover the isolate each rich in particular heavy metals by filtering the isolate to isolate each of the pH adjustment.

【0013】[0013]

【実施例】以下、本発明の実施例1に係る飛灰からの重
金属類の回収方法を実現する重金属類の回収装置を示す
系統図の図1を参照しながら説明すると、図に示す符号
1は図示しないごみ焼却炉から発生した焼却灰aや飛灰
bを溶融するための溶融炉または高温加熱炉(以下、溶
融炉という。)である。焼却灰aや飛灰bの溶融に際し
てこの溶融炉1から排出された排ガスは、先ず洗浄水
と、硫化物である水硫化ソーダ(NaHS)または硫化
ソーダ(Na2 S)およびアルカリ剤である苛性ソーダ
(NaOH)が供給される湿式スクラバー2に送り込ま
れる。
EXAMPLE A description will be given below with reference to FIG. 1 of a system diagram showing a heavy metal recovery apparatus for realizing a method for recovering heavy metals from fly ash according to Example 1 of the present invention. Is a melting furnace or a high-temperature heating furnace (hereinafter referred to as a melting furnace) for melting incineration ash a and fly ash b generated from a refuse incinerator (not shown). Exhaust gas discharged from the melting furnace 1 at the time of melting the incineration ash a and the fly ash b is first of all cleaning water, sodium hydrosulfide (NaHS) or sodium sulfide (Na 2 S) which is a sulfide, and caustic soda which is an alkaline agent. (NaOH) is fed to the wet scrubber 2.

【0014】ところで、図1には、溶融炉1に焼却灰a
と飛灰bの他に塩素含有物である塩素含有廃棄物cも投
入することが示されている。このように、溶融炉1に塩
素含有廃棄物cを投入するのは、これら焼却灰aや飛灰
bに含まれている塩素成分が少ない場合に限られる。つ
まり、塩素成分を多く含むごみの焼却により得られた焼
却灰aや飛灰bを溶融処理する場合には、溶融炉1から
排出される排ガス中には飛灰や揮散重金属類を溶解する
のに充分な量の塩素成分が含まれており、これが洗浄水
による洗浄により溶解し、洗浄排水中に塩酸(HCl)
として介在するため、塩素含有廃棄物cを投入する必要
がないものである。
By the way, in FIG. 1, incineration ash a is placed in the melting furnace 1.
In addition to fly ash b, chlorine-containing waste c that is a chlorine-containing substance is also introduced. Thus, the chlorine-containing waste c is charged into the melting furnace 1 only when the incineration ash a and the fly ash b contain a small amount of chlorine components. That is, when incineration ash a or fly ash b obtained by incineration of waste containing a large amount of chlorine components is subjected to melting treatment, fly ash and volatile heavy metals are dissolved in the exhaust gas discharged from the melting furnace 1. Contains a sufficient amount of chlorine component, which is dissolved by washing with washing water and hydrochloric acid (HCl) in the washing wastewater.
Therefore, it is not necessary to input the chlorine-containing waste c.

【0015】湿式スクラバー2に送り込まれた排ガスは
洗浄水で洗浄されて急冷されると共に、この洗浄により
生じる洗浄排水には、そのpH調整のために、NaHS
またはNa2 SおよびNaOHが供給され、洗浄排水の
pHは0.4未満に調整される。洗浄により飛灰や揮散
重金属が除去された排ガスは排ガス処理装置8に送り込
まれ、ここにおいて排ガス中の未除去物質であるNOX
や、極く微量の除去残物質であるHCL、重金属類、ダ
イオキシン類等が除去され、誘引送風機9で吸引される
と共に、煙突10から大気中に放出される。
The exhaust gas sent to the wet scrubber 2 is washed with cleaning water and rapidly cooled, and the cleaning wastewater generated by this cleaning is adjusted to NaHS in order to adjust its pH.
Alternatively, Na 2 S and NaOH are supplied and the pH of the cleaning waste water is adjusted to less than 0.4. The exhaust gas from which fly ash and volatilized heavy metals have been removed by cleaning is sent to the exhaust gas treatment device 8, where NO x, which is an unremoved substance in the exhaust gas.
In addition, HCL, heavy metals, dioxins, and the like, which are trace amounts of residual substances to be removed, are removed, sucked by the induced blower 9, and discharged from the chimney 10 to the atmosphere.

【0016】ところで、湿式スクラバー2にNaHSま
たはNa2 Sを投入するのは、洗浄排水中に多量に含ま
れている塩酸により溶解しているCu等の重金属類を硫
化物(CuS,PbS,ZnS)として効果的に回収す
るためである。また、このようにCu等の重金属類を硫
化物にするのは、Cu等の重金属類を効果的に回収する
という狙い以外に、ダイオキシン類の生成率が高くなる
(固体化した銅がダイオキシン類生成のための触媒にな
るといわれている。)恐れがあるので、Cu等の重金属
類の活性を低減してダイオキシン類の生成率を抑制する
という狙いもある。因みに、湿式スクラバー2の入口と
出口とにおける排ガス中のダイオキシン類のO2 12%
換算値と毒性等価換算値とを示すと表1の通りである。
By the way, the introduction of NaHS or Na 2 S into the wet scrubber 2 is carried out by removing heavy metals such as Cu dissolved in hydrochloric acid contained in a large amount in the cleaning drainage from sulfides (CuS, PbS, ZnS). ) Is effectively collected. In addition, making heavy metals such as Cu into sulfides in this way increases the production rate of dioxins (the solidified copper is dioxins), in addition to the purpose of effectively recovering heavy metals such as Cu. It is said to be a catalyst for production.) Therefore, there is also the aim of reducing the activity of heavy metals such as Cu and suppressing the production rate of dioxins. By the way, O 2 12% of dioxins in the exhaust gas at the inlet and outlet of the wet scrubber 2
Table 1 shows the converted value and the toxicity equivalent converted value.

【0017】[0017]

【表1】 上記表1によれば、湿式スクラバー2の出口における排
ガス中のダイオキシン類の濃度はガイドライン0.5m
g/m3 N(毒性等価換算値)の1/2になっており、
ダイオキシン類の削減にとって極めて効果的である。ま
た、湿式スクラバー2から排出された洗浄排水中に溶解
している重金属類の種類とその濃度(mg/リットル)
は、表2に示すとおりである。
[Table 1] According to Table 1 above, the concentration of dioxins in the exhaust gas at the outlet of the wet scrubber 2 is 0.5 m according to the guideline.
It is 1/2 of g / m 3 N (toxic equivalent conversion value),
It is extremely effective in reducing dioxins. Also, the type and concentration (mg / liter) of heavy metals dissolved in the cleaning wastewater discharged from the wet scrubber 2.
Is as shown in Table 2.

【0018】[0018]

【表2】 [Table 2]

【0019】湿式スクラバー2から排出されると共に、
一次沈澱槽3に流入した洗浄排水中には、さらにNaH
SまたはNa2 SおよびNaOHが供給され、重金属類
のうち特にCu成分が多く分離するように、pHが0.
4未満になるように最終調整されると共に、凝集剤が添
加される。さすれば、洗浄排水から分離した重金属塩類
は複数の凝集物となり、洗浄排水はスラリー状になる。
なお、Cu成分を特に多く分離させる洗浄排水のpHは
好ましくは0.1〜0.3である。
While being discharged from the wet scrubber 2,
In the washing wastewater that has flowed into the primary settling tank 3, NaH is further added.
S or Na 2 S and NaOH are supplied, and the pH is adjusted to 0.
The final adjustment is made to be less than 4, and the coagulant is added. Then, the heavy metal salts separated from the cleaning waste water become a plurality of aggregates, and the cleaning waste water becomes a slurry.
The pH of the cleaning wastewater that separates a large amount of Cu component is preferably 0.1 to 0.3.

【0020】次いで、複数の凝集物を含むスラリー状の
洗浄排水は一次濾過槽4に送られ、この一次濾過槽4に
より凝集物が濾過される。濾過物は、水洗浄された後乾
燥され、Cu成分を多く含む一次回収物として回収され
る。なお、洗浄排水のpHは、一次沈澱槽3に設けられ
たpH計3aによって測定される。また、NaHSまた
はNa2 SおよびNaOHは、上記のとおり、一次沈澱
槽3においても供給するようにしているが、これは洗浄
排水のpHを微調整するためである。
Next, the slurry-like cleaning waste water containing a plurality of aggregates is sent to the primary filtration tank 4, and the primary filtration tank 4 filters the aggregates. The filtered product is washed with water and then dried to be recovered as a primary recovered product containing a large amount of Cu component. The pH of the cleaning wastewater is measured by the pH meter 3a provided in the primary precipitation tank 3. Further, NaHS or Na 2 S and NaOH are also supplied in the primary precipitation tank 3 as described above, for the purpose of finely adjusting the pH of the washing wastewater.

【0021】一次濾過槽4で濾過された一次濾過水は、
二次沈澱槽5に送られ、そしてこの二次沈澱槽5中の一
次濾過水に、さらにNaHSまたはNa2 SおよびNa
OHが供給され、重金属類のうち、特にPb成分とZn
成分とが多く分離するように、一次濾過水のpHが0.
4以上になるように調整されると共に、凝集剤が添加さ
れる。
The primary filtered water filtered in the primary filtering tank 4 is
It is sent to the secondary precipitation tank 5, and the primary filtered water in the secondary precipitation tank 5 is further added with NaHS or Na 2 S and Na.
OH is supplied, and among the heavy metals, especially Pb component and Zn
The pH of the primary filtered water is 0.
It is adjusted to 4 or more and a coagulant is added.

【0022】すると、上記実施例1と同様に、さらに分
離した他の重金属塩類は複数の凝集物となり、洗浄排水
はスラリー状になるので、このスラリー状の洗浄排水が
二次濾過槽6に供給されて濾過される。濾過物は、水洗
浄された後乾燥され、二次回収物として回収される。一
方、二次濾過水は排水処理装置7に送られ、所定処理後
に放水される。なお、この洗浄排水のpHは、二次沈澱
槽5に設けられたpH計5aによって測定される。
Then, as in Example 1, the other separated heavy metal salts become a plurality of agglomerates, and the cleaning waste water becomes a slurry, so that the slurry cleaning waste water is supplied to the secondary filtration tank 6. And filtered. The filtered product is washed with water, dried, and then recovered as a secondary recovered product. On the other hand, the secondary filtered water is sent to the wastewater treatment device 7 and discharged after a predetermined treatment. The pH of this cleaning waste water is measured by a pH meter 5a provided in the secondary precipitation tank 5.

【0023】以上のようにして回収した一次回収物と、
二次回収物との重金属類等の含有割合(%)は表3に示
すとおりである。
The primary recovered material recovered as described above,
Table 3 shows the content ratio (%) of heavy metals and the like in the secondary recovered product.

【0024】[0024]

【表3】 [Table 3]

【0025】上記表2によれば、一次回収物中には5
3.7%のCu成分が含まれており、また二次回収物中
には50.0%もの(Pb+Zn)成分(Pb;16.
0%,Zn;34.0%)が含まれている。従って、一
次回収物はCuの精錬原料として使用することができ、
また二次回収物は(Pb+Zn)の精錬原料として使用
することができるので、ただ単なる重金属類の除去と異
なり、資源の有効活用に大いに貢献することができる。
しかも、ごみ自身に含まれている塩素分を塩酸にし、こ
れにより飛灰を溶解するため、鉱酸等の溶解酸を用いる
従来例2に比較して、重金属類をより安価に回収するこ
とができる。
According to Table 2 above, there are 5 in the primary recovery product.
It contained 3.7% of Cu component, and 50.0% of (Pb + Zn) component (Pb; 16.
0%, Zn; 34.0%). Therefore, the primary recovery product can be used as a Cu refining raw material,
In addition, since the secondary recovered product can be used as a raw material for refining (Pb + Zn), it can greatly contribute to effective use of resources, unlike the simple removal of heavy metals.
Moreover, since the chlorine content contained in the refuse itself is converted to hydrochloric acid and the fly ash is dissolved by this, it is possible to recover the heavy metals at a lower cost as compared with Conventional Example 2 in which a dissolved acid such as a mineral acid is used. it can.

【0026】次に、本発明の実施例2に係る飛灰からの
重金属類の回収方法を実現する重金属類の回収装置を示
す系統図の図2を参照しながら説明すると、同図に示す
符号21は焼却炉から発生した焼却灰aや飛灰bを溶融
する溶融炉である。この溶融炉21から排出された排ガ
スは、先ず洗浄水と、NaHSまたはNa2 SおよびN
aOHが供給される第1段の湿式スクラバー22に送り
込まれる。この実施例の場合も上記実施例1と同様に、
溶融炉21には焼却灰aや飛灰bの他に、必要に応じて
塩素含有廃棄物cが投入される。
Next, a description will be given with reference to FIG. 2 of a system diagram showing a heavy metal recovery apparatus for realizing a heavy metal recovery method from fly ash according to a second embodiment of the present invention. Reference numeral 21 is a melting furnace for melting incineration ash a and fly ash b generated from the incinerator. The exhaust gas discharged from the melting furnace 21 is first washed with washing water and NaHS or Na 2 S and N.
It is sent to the first stage wet scrubber 22 to which aOH is supplied. Also in the case of this embodiment, as in the above-described first embodiment,
In addition to incineration ash a and fly ash b, chlorine-containing waste c is charged into the melting furnace 21 as required.

【0027】第1段の湿式スクラバー22に送り込まれ
た排ガスは一次洗浄水で洗浄されると共に、この洗浄に
より生じる一次洗浄排水には、そのpHが0.4未満に
なるように、NaHSまたはNa2 SおよびNaOHが
供給される。一方、一次洗浄によりダストや揮散重金属
塩類が除去された一次洗浄排ガスは、第2段の湿式スク
ラバー25に送り込まれる。
The exhaust gas sent to the wet scrubber 22 of the first stage is washed with primary washing water, and the primary washing wastewater generated by this washing is adjusted to have a pH of less than 0.4 by NaHS or Na. 2 S and NaOH are supplied. On the other hand, the primary cleaning exhaust gas from which dust and volatile heavy metal salts have been removed by the primary cleaning is sent to the wet scrubber 25 in the second stage.

【0028】そして、洗浄水により洗浄された二次洗浄
排ガスは排ガス処理装置29に送り込まれ、ここにおい
て排ガス中の未除去物質であるNOX や、極く微量の除
去残物質であるHCL、重金属類、ダイオキシン類等が
除去され、誘引送風機30で吸引されると共に、煙突3
1から大気中に放出される。なお、第1段の湿式スクラ
バー22に供給するNaHSまたはNa2 SおよびNa
OHの量は後述する一次沈澱槽23に設けられているp
H計23aの測定値によって決定される。
Then, the secondary cleaning exhaust gas cleaned with the cleaning water is sent to the exhaust gas treatment device 29, where NO X which is an unremoved substance in the exhaust gas, HCL which is an extremely small amount of the removal residual substance, and heavy metal. And dioxins are removed and sucked by the induction blower 30, and the chimney 3
1 is released into the atmosphere. In addition, NaHS or Na 2 S and Na supplied to the wet scrubber 22 of the first stage
The amount of OH is p provided in the primary precipitation tank 23 described later.
It is determined by the measurement value of the H meter 23a.

【0029】このようにして、0.4未満になるように
pH調整された一次洗浄排水からは、特にCu成分の多
い重金属類が硫化物として分離し、一次沈澱槽23に流
入する。一次沈澱槽23に流入した一次洗浄排水に凝集
剤が添加され、硫化物として分離した重金属塩類は複数
の凝集物となり、一次洗浄排水はスラリー状になる。次
いで、複数の凝集物を含むスラリー状の一次洗浄排水は
一次濾過槽24に送られ、この一次濾過槽24により凝
集物が濾過される。濾過物は、水洗浄された後乾燥さ
れ、Cu成分を多く含む一次回収物として回収される。
In this way, from the primary cleaning waste water whose pH is adjusted to less than 0.4, heavy metals having a particularly high Cu content are separated as sulfides and flow into the primary precipitation tank 23. A flocculant is added to the primary cleaning wastewater that has flowed into the primary settling tank 23, the heavy metal salts separated as sulfides become a plurality of agglomerates, and the primary cleaning wastewater becomes a slurry. Next, the slurry-like primary cleaning wastewater containing a plurality of aggregates is sent to the primary filtration tank 24, and the aggregates are filtered by this primary filtration tank 24. The filtered product is washed with water and then dried to be recovered as a primary recovered product containing a large amount of Cu component.

【0030】一次濾過槽24で濾過された一次濾過水
は、前記第2段の湿式スクラバー25に送られ、第1段
の湿式スクラバー22から流入する一次洗浄排ガスの二
次洗浄水により二次洗浄排水と混合される。そしてもこ
の混合排水に、さらにNaHSまたはNa2 SおよびN
aOHが供給され、重金属類のうち特にPb成分とZn
成分とが多く分離するように、混合排水のpHが0.4
以上になるように調整されると共に、二次沈澱槽26に
送られる。第2段の湿式スクラバー25に供給するNa
HSまたはNa2 SおよびNaOHの量は前記二次沈澱
槽26に設けられているpH計26aの測定値によって
決定される。
The primary filtered water filtered in the primary filtration tank 24 is sent to the second-stage wet scrubber 25 and second-cleaned by the secondary-cleaning water of the primary-cleaning exhaust gas flowing from the first-stage wet scrubber 22. Mixed with drainage. And this mixed wastewater also contains NaHS or Na 2 S and N.
aOH is supplied, and among the heavy metals, especially Pb component and Zn
The pH of the mixed wastewater is 0.4 so that the components are separated from each other.
It is adjusted as described above and sent to the secondary precipitation tank 26. Na supplied to the second-stage wet scrubber 25
The amounts of HS or Na 2 S and NaOH are determined by the measured value of the pH meter 26a provided in the secondary precipitation tank 26.

【0031】そして、この二次沈澱槽26中の混合排水
に凝集剤が添加されると、上記実施例とと同様に、さら
に分離した他の重金属塩類は複数の凝集物となり、混合
排水はスラリー状になる。このスラリー状の混合排水が
二次濾過槽27に送られて濾過される。濾過物は、水洗
浄された後乾燥され、(Pb+Zn)成分を多く含む二
次回収物として回収される。一方、二次濾過水は排水処
理装置28に送られ、所定処理後に放水される。
When a coagulant is added to the mixed wastewater in the secondary precipitation tank 26, the other separated heavy metal salts become a plurality of coagulates, and the mixed wastewater is a slurry, as in the above embodiment. Become a state. This slurry-like mixed wastewater is sent to the secondary filtration tank 27 and filtered. The filtered product is washed with water and then dried to be recovered as a secondary recovered product containing a large amount of (Pb + Zn) components. On the other hand, the secondary filtered water is sent to the wastewater treatment device 28 and discharged after a predetermined treatment.

【0032】このようにCu成分を多く含む一次回収物
と、Pb成分とZn成分とを多く含む二次回収物とを得
ることができるので、本実施例は上記実施例と同効であ
る。但し、本実施例によれば、第1段の湿式スクラバー
22と第2段の湿式スクラバー25との2段構えで、第
1段の湿式スクラバー22を酸スクラバーとし、第2段
の湿式スクラバー25を中性スクラバー(アルカリスク
ラバー)にすることができるので、排ガス中の重金属類
をより確実に捕捉、処理し得るという優れた効果があ
る。
As described above, the primary recovery product containing a large amount of Cu component and the secondary recovery product containing a large amount of Pb component and Zn component can be obtained. Therefore, the present embodiment has the same effect as the above embodiment. However, according to this embodiment, the wet scrubber 22 of the first stage and the wet scrubber 25 of the second stage are arranged in two stages, and the wet scrubber 22 of the first stage is an acid scrubber, and the wet scrubber 25 of the second stage is used. Since it can be used as a neutral scrubber (alkali scrubber), there is an excellent effect that heavy metals in exhaust gas can be more reliably captured and treated.

【0033】なお、3段構え以上の湿式スクラバー構成
にすることも可能である。2段構えの湿式スクラバー構
成で実用上の支障はなく、これにより、HClや重金属
類を充分除去することができる。
It is also possible to adopt a wet scrubber structure having three or more stages. The two-stage wet scrubber configuration has no problem in practical use, whereby HCl and heavy metals can be sufficiently removed.

【0034】また、濾過水を一次濾過槽と二次濾過槽の
間で循環させ、その一部を抜き出して2段目の湿式スク
ラバーに送り込み、この実施例2と同様の処理をするこ
ともできる。この方法によると、未反応硫黄分を有効活
用することができ、NaHSまたはNa2 Sの供給量を
抑制することができるので、より一層の重金属類回収コ
ストの低減に寄与することができる。
Further, it is possible to circulate the filtered water between the primary filtration tank and the secondary filtration tank, extract a part of the filtered water and send it to the second-stage wet scrubber to perform the same treatment as in the second embodiment. . According to this method, the unreacted sulfur content can be effectively utilized and the supply amount of NaHS or Na 2 S can be suppressed, which can further contribute to the reduction of the heavy metal recovery cost.

【0035】[0035]

【発明の効果】以上詳述したように、本発明の請求項1
乃至3に係る焼却灰や費這うの溶融に際して生じる排ガ
スからの重金属類の回収方法によれば、ごみの焼却によ
り生じる溶融処理すべき焼却灰や飛灰に含まれている塩
素分を活用して排ガス中から飛灰や揮散重金属類を捕
捉、かつ溶解すると共に、洗浄排水中から重金属類をあ
る特定の重金属を多く含む硫化物として分離させて回収
するので、従来例1のように回収物中に多くの重金属類
が無分別に含まれていることがないから、回収物を精錬
原料として用いることができ、回収した重金属のリサイ
クルを容易に行うことができる。
As described in detail above, claim 1 of the present invention
According to the method of recovering heavy metals from exhaust gas generated during melting of incinerated ash or crawling according to 3 to 3, chlorine content contained in incinerated ash and fly ash to be melt-processed by incineration of waste is utilized. Fly ash and volatilized heavy metals are captured and dissolved from the exhaust gas, and the heavy metals are separated from the cleaning wastewater as sulfides containing a large amount of a specific heavy metal and recovered. Since many heavy metals are not contained indiscriminately, the recovered material can be used as a refining raw material, and the recovered heavy metal can be easily recycled.

【0036】また、従来例2のように、飛灰等を溶解す
るのに鉱酸等の薬剤を用いる必要がないから、重金属類
を低コストで回収することができると共に、上記のとお
り塩素分を活用して飛灰や重金属類を溶解させるので、
重金属類をより確実に分離させて回収することができる
という多大な効果がある。
Further, unlike the conventional example 2, since it is not necessary to use a chemical such as a mineral acid to dissolve fly ash or the like, it is possible to recover heavy metals at a low cost and, as described above, chlorine Is used to dissolve fly ash and heavy metals, so
There is a great effect that the heavy metals can be separated and recovered more reliably.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明の実施例1に係る飛灰からの重金属類の
回収方法を実現する重金属類の回収装置を示す系統図で
ある。
FIG. 1 is a system diagram showing a heavy metal recovery apparatus that realizes a method of recovering heavy metals from fly ash according to a first embodiment of the present invention.

【図2】本発明の実施例2に係る飛灰からの重金属類の
回収方法を実現する重金属類の回収装置を示す系統図で
ある。
FIG. 2 is a system diagram showing a heavy metal recovery apparatus that realizes a method of recovering heavy metals from fly ash according to a second embodiment of the present invention.

【符号の説明】[Explanation of symbols]

1…溶融炉 2…湿式スクラバー 3…一次沈澱槽,3a…pH計 4…一次濾過槽 5…二次沈澱槽,5a…pH計 6…二次濾過槽 7…排水処理装置 8…排ガス処理装置 9…誘引送風機 10…煙突 21…溶融炉 22…第1段の湿式スクラバー 23…一次沈澱槽,23a…pH計 24…一次濾過槽 25…第2段の湿式スクラバー 26…二次沈澱槽,26a…pH計 27…二次濾過槽 28…排水処理装置 29…排ガス処理装置 30…誘引送風機 31…煙突 a…焼却灰 b…飛灰 c…塩素含有廃棄物 1 ... Melting furnace 2 ... Wet scrubber 3 ... Primary precipitation tank, 3a ... pH meter 4 ... Primary filtration tank 5 ... Secondary precipitation tank, 5a ... pH meter 6 ... Secondary filtration tank 7 ... Wastewater treatment equipment 8 ... Exhaust gas treatment equipment 9 ... Induction blower 10 ... Chimney 21 ... Melting furnace 22 ... First stage wet scrubber 23 ... Primary precipitation tank, 23a ... pH meter 24 ... Primary filtration tank 25 ... Second stage wet scrubber 26 ... Secondary precipitation tank, 26a ... pH meter 27 ... Secondary filtration tank 28 ... Wastewater treatment device 29 ... Exhaust gas treatment device 30 ... Induction blower 31 ... Chimney a ... Incinerated ash b ... Fly ash c ... Chlorine-containing waste

Claims (3)

【特許請求の範囲】[Claims] 【請求項1】 溶融炉または高温加熱炉で焼却灰や飛灰
等を溶融処理するに際して発生する排ガスから重金属類
を回収する飛灰からの重金属類の回収方法において、前
記排ガスを湿式スクラバーにより洗浄し、洗浄後の排ガ
スを排ガス処理装置に導入して処理する一方、洗浄によ
り生じる洗浄排水に水硫化ソーダまたは硫化ソーダ等の
硫化物および苛性ソーダ等のアルカリ剤を添加してpH
を0.4未満に調整し、このpH調整液から分離した分
離物を濾過すると共に、濾過水に順次前記硫化物とアル
カリ剤とを供給してpHを調整し、pH調整の都度分離
する分離物を濾過することによりそれぞれ特定の重金属
類を多く含む分離物を回収することを特徴とする焼却灰
や飛灰の溶融に際して生じる排ガスからの重金属類の回
収方法。
1. A method for recovering heavy metals from fly ash, which comprises recovering heavy metals from exhaust gas generated when melting incineration ash, fly ash, etc. in a melting furnace or a high-temperature heating furnace, and washing the exhaust gas with a wet scrubber. Then, while introducing the exhaust gas after cleaning into the exhaust gas treatment equipment for processing, the cleaning wastewater generated by cleaning is treated with sulfides such as sodium hydrosulfide or sodium sulfide and an alkali agent such as caustic soda to adjust the pH.
Is adjusted to less than 0.4, the separated product separated from the pH adjusting solution is filtered, and the sulfide and the alkaline agent are sequentially supplied to the filtered water to adjust the pH, and the separation is performed each time the pH is adjusted. A method for recovering heavy metals from exhaust gas produced during melting of incinerated ash or fly ash, characterized in that separated materials containing a large amount of specific heavy metals are recovered by filtering the materials.
【請求項2】 溶融炉または高温加熱炉で焼却灰や飛灰
等を溶融処理するに際して発生する排ガスから重金属類
を回収する飛灰からの重金属類の回収方法において、前
記排ガスを湿式スクラバーにより洗浄し、洗浄後の排ガ
スを順次次段の湿式スクラバーにより洗浄し、最終段の
湿式スクラバーによる洗浄後の排ガスを排ガス処理装置
に導入して処理する一方、第一段の湿式スクラバーにお
ける洗浄により生じる洗浄排水に水硫化ソーダまたは硫
化ソーダ等の硫化物および苛性ソーダ等のアルカリ剤を
添加してpHを0.4未満に調整し、このpH調整液か
ら分離した分離物を濾過すると共に、濾過水を次段の湿
式スクラバーに送り、この濾過水と次段の湿式スクラバ
ーによる洗浄により生じる洗浄排水とに前記硫化物およ
びアルカリ剤を添加して、pHを予め設定した値に調整
し、これらpH調整液から分離した分離物を濾過すると
いうように、次段以降の湿式スクラバーにおける濾過水
と洗浄排水に対しても前記次段の湿式スクラバーにおけ
る濾過水と洗浄排水と同様の処理を行うことによりそれ
ぞれ特定の重金属類を多く含む分離物を回収することを
特徴とする焼却灰や飛灰の溶融に際して生じるハイガス
からの重金属類の回収方法。
2. A method for recovering heavy metals from fly ash for recovering heavy metals from exhaust gas generated when melting incineration ash, fly ash, etc. in a melting furnace or a high-temperature heating furnace is washed with a wet scrubber. Then, the exhaust gas after cleaning is sequentially cleaned by the wet scrubber in the next stage, and the exhaust gas after cleaning by the wet scrubber in the final stage is introduced into the exhaust gas treatment device for processing, while the cleaning caused by the cleaning in the wet scrubber in the first stage The pH of the wastewater is adjusted to less than 0.4 by adding sulfides such as sodium hydrosulfide or sodium sulfide and an alkali agent such as caustic soda, and the separated product separated from this pH-adjusted solution is filtered. Sent to the wet scrubber of the next stage, and the sulfide and alkali agent are added to the filtered water and the cleaning wastewater generated by the cleaning by the wet scrubber of the next stage. Then, the pH is adjusted to a preset value, and the separated substances separated from these pH adjusting liquids are filtered. A method for recovering heavy metals from high gas generated during melting of incinerated ash and fly ash, characterized in that separated materials containing a large amount of specific heavy metals are recovered by performing the same processing as filtered water and cleaning wastewater in a scrubber. .
【請求項3】 溶融または高温加熱処理により発生する
塩化物の発生量が少ないときには、塩化物の発生量に応
じて予め前記焼却灰や飛灰等に塩素含有物を混入して溶
融または高温加熱処理することを特徴とする請求項1ま
たは2に記載の焼却灰や飛灰の溶融に際して生じる排ガ
スからの重金属類の回収方法。
3. When the amount of chloride generated by melting or high-temperature heat treatment is small, chlorine-containing substances are mixed in advance in the incineration ash or fly ash according to the amount of chloride generated, and melting or high-temperature heating is performed. The method for recovering heavy metals from exhaust gas produced during melting of incinerated ash or fly ash according to claim 1 or 2, which is characterized by treating the ash.
JP17772795A 1995-07-13 1995-07-13 Recovery method of heavy metals from exhaust gas generated during melting of incineration ash and fly ash Expired - Lifetime JP3009607B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP17772795A JP3009607B2 (en) 1995-07-13 1995-07-13 Recovery method of heavy metals from exhaust gas generated during melting of incineration ash and fly ash

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17772795A JP3009607B2 (en) 1995-07-13 1995-07-13 Recovery method of heavy metals from exhaust gas generated during melting of incineration ash and fly ash

Publications (2)

Publication Number Publication Date
JPH0924240A true JPH0924240A (en) 1997-01-28
JP3009607B2 JP3009607B2 (en) 2000-02-14

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Country Status (1)

Country Link
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