JPH11192471A - Treatment of melted fly ash or incineration fly ash - Google Patents
Treatment of melted fly ash or incineration fly ashInfo
- Publication number
- JPH11192471A JPH11192471A JP10305733A JP30573398A JPH11192471A JP H11192471 A JPH11192471 A JP H11192471A JP 10305733 A JP10305733 A JP 10305733A JP 30573398 A JP30573398 A JP 30573398A JP H11192471 A JPH11192471 A JP H11192471A
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- JP
- Japan
- Prior art keywords
- fly ash
- treated
- incinerated
- elution
- heavy metals
- 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.)
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- Fire-Extinguishing Compositions (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、溶融炉から発生す
る溶融飛灰又は焼却炉から発生する焼却飛灰に含まれる
重金属の溶出を防止すると共に、ダイオキシンを分解す
る溶融飛灰又は焼却飛灰の重金属溶出防止処理方法並び
にダイオキシン分解方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten fly ash generated from a melting furnace or a fly ash generated from an incinerator, which prevents leaching of heavy metals contained therein and decomposes dioxin. And a dioxin decomposition method.
【0002】[0002]
【従来の技術】近年、都市ゴミ及び/又は産業廃棄物を
溶融炉で溶融処理したり、焼却炉で焼却処理するに際し
て、この溶融炉、又は、焼却炉から発生する排ガス中の
塩化水素等の酸性成分を吸着、固定するために、排ガス
中へ消石灰(Ca(OH)2 )を吹込む方法が実施され
ている。そして、このような排ガス中には溶融処理中又
は焼却処理中に発生する焼成灰の中の比較的粒径の小さ
い溶融飛灰又は焼却飛灰(以下、単に飛灰と呼ぶ。)が
含まれて、集塵機等で捕集されるようになっている。飛
灰は多くの場合、最終処分場に埋め立て処分されるが、
飛灰中には鉛、カドミニウム等の有害な重金属、及び有
毒なダイオキシン等が含まれていて、雨水等の作用によ
り周囲に溶出して環境を汚染させる要因となる。このよ
うな飛灰の重金属の溶出を防止する方法には、(1)溶
融固化、(2)薬剤処理、(3)セメント処理、(4)
酸抽出の4種の方法が知られている。溶融固化方法は飛
灰をその溶融温度まで加熱して、重金属を溶融スラグの
中に包括する方法、薬剤処理は、キレート法に代表され
るように薬剤の中に化学的に重金属を包括する方法であ
る。また、セメント処理は飛灰をセメントと混ぜて固形
化する方法、酸抽出法は、飛灰を酸の中に浸して重金属
を抽出除去する方法である。一方、飛灰中のダイオキシ
ンを分解する方法としては、例えば、特公平6−388
63号公報によれば、飛灰を、酸素欠乏状態で200℃
ないし550℃で加熱することでダイオキシンを含むポ
リハロゲン化化合物を分解するとしている。また、特開
平8−303741号公報によれば、飛灰を、400〜
550℃に加熱することで、ダイオキシン等の有害な有
機塩素化合物を分解できるとしている。なお、該公報、
第5回廃棄物学会研究発表会講演論文集(1994年1
0月20日廃棄物学会発行)P.398〜400に記載
の論文「都市ごみ焼却飛灰の重金属溶出特性」(三井造
船株式会社執筆)及び三井造船株式会社発行のダイオブ
レーカー(飛灰加熱脱塩素化処理設備)説明資料のいず
れにも、分解処理雰囲気条件として、温度以外の条件、
例えば低酸素状態等の記載は全くみられない。2. Description of the Related Art In recent years, when municipal garbage and / or industrial waste is melted in a melting furnace or incinerated in an incinerator, hydrogen chloride or the like in exhaust gas generated from the melting furnace or incinerator is used. In order to adsorb and fix acidic components, a method of blowing slaked lime (Ca (OH) 2) into exhaust gas has been practiced. Such flue gas contains molten fly ash or incinerated fly ash (hereinafter simply referred to as fly ash) having a relatively small particle diameter in the calcined ash generated during the melting process or the incineration process. And are collected by a dust collector or the like. Fly ash is often landfilled at a final disposal site,
Fly ash contains harmful heavy metals such as lead and cadmium, and toxic dioxins, etc., which elute into the surroundings due to the action of rainwater or the like and become a factor that pollutes the environment. Methods for preventing the elution of heavy metals from fly ash include (1) melt solidification, (2) chemical treatment, (3) cement treatment, and (4)
Four methods of acid extraction are known. The melt-solidification method involves heating fly ash to its melting temperature and entrapping heavy metals in the molten slag.The chemical treatment involves chemically encapsulating heavy metals in chemicals as represented by the chelate method. It is. The cement treatment is a method in which fly ash is mixed with cement to be solidified, and the acid extraction method is a method in which fly ash is immersed in an acid to extract and remove heavy metals. On the other hand, as a method for decomposing dioxin in fly ash, for example, Japanese Patent Publication No. 6-388
According to Japanese Patent No. 63, fly ash is stored at 200 ° C. in an oxygen-deficient state.
It is said that heating at 550 ° C. to decompose polyhalogenated compounds containing dioxin. According to JP-A-8-303741, fly ash is reduced to 400 to
By heating to 550 ° C., harmful organic chlorine compounds such as dioxin can be decomposed. The publication,
Proceedings of the 5th Waste Management Research Conference (January 1994)
Published by Japan Society of Waste Management on 20th of October) 398-400, "Leaching characteristics of heavy metals in municipal solid waste incineration fly ash" (authored by Mitsui Engineering & Shipbuilding Co., Ltd.) and Die Breaker (fly ash heat dechlorination equipment) issued by Mitsui Engineering & Shipbuilding Co., Ltd. , As decomposition atmosphere conditions other than temperature,
For example, there is no description of a hypoxic state or the like.
【0003】[0003]
【発明が解決しようとする課題】しかしながら、前記の
飛灰を溶融固化する方法、飛灰に薬剤及びセメントを混
ぜる方法、もしくは飛灰中の重金属を酸抽出させる方法
では、いずれもコスト的に高価になり、また処理後の容
積が大きくなるという問題がある。さらに、都市ごみ等
では排ガス中の酸性ガスの中和処理剤として消石灰が添
加されることが多いので、溶融炉から発生する溶融飛灰
中又は焼却炉から発生する焼却飛灰中には未反応のCa
O分が含まれ、飛灰を水に浸漬したときのpHが高くな
って、重金属の溶出が助長されるという問題があった。
一方、ダイオキシンを分解する方法において、酸素欠乏
状態で分解処理するためには、特公平6−38863号
公報に記載の通り、空気の侵入を防止するかあるいは、
処理装置に窒素等の不活性ガスを充填する必要がある。
このいずれの場合も酸素欠乏状態を常時維持するために
は処理装置のシールを確実に行なわなければならない。
処理装置には当然飛灰の供給口、排出口が存在してお
り、飛灰の出し入れと共に気密性を確保する必要上、供
給、排出装置としては構造が複雑となる。もちろん、そ
れ以外に装置各所のシール構造も大がかりとなるために
装置全体としては、かなり高価になってしまう。また、
不活性ガスを用いる場合当然、常時補充が必要なため、
その分、運転費用が嵩むこととなる。もう一つの、非低
酸素状態(以後空気中の酸化雰囲気と呼ぶ)における、
400〜550℃加熱処理であるが、発明者らが実施し
た空気中の酸化雰囲気での実験によると、後述する表
7、図3に示すように、ダイオキシンを確実に分解する
ためには、550℃の加熱温度では不充分である。本発
明はかかる事情に鑑みてなされたもので、処理容積を増
やすことなく安価に飛灰中に含まれる重金属の環境への
溶出を防止できる飛灰の重金属溶出防止処理方法と、設
備費運転費共安価で、かつ、確実に、ダイオキシンを分
解できる飛灰のダイオキシン分解方法を提供することを
目的とする。However, the above methods of melting and solidifying the fly ash, mixing the fly ash with a chemical and cement, or extracting the heavy metals in the fly ash by acid are all expensive. In addition, there is a problem that the volume after processing increases. In addition, slaked lime is often added as a neutralizing agent for acid gas in exhaust gas in municipal solid waste, etc., so it does not react during fly ash generated from melting furnaces or fly ash generated from incinerators. Ca
There is a problem that the O content is included and the pH when fly ash is immersed in water increases, which promotes the elution of heavy metals.
On the other hand, in the method of decomposing dioxin, in order to decompose in a state of oxygen deficiency, as described in JP-B-6-38863, air intrusion is prevented or
It is necessary to fill the processing apparatus with an inert gas such as nitrogen.
In any of these cases, in order to always maintain the oxygen-deficient state, the processing apparatus must be securely sealed.
Of course, the processing apparatus has a supply port and a discharge port for fly ash, and the structure of the supply and discharge device becomes complicated because it is necessary to secure airtightness while taking in and out the fly ash. Of course, in addition to that, the sealing structure of each part of the apparatus becomes large, so that the whole apparatus becomes considerably expensive. Also,
Of course, when using an inert gas, it is necessary to always replenish it.
The operating cost increases accordingly. In another non-hypoxic condition (hereinafter referred to as oxidizing atmosphere in air),
Although the heat treatment is performed at 400 to 550 ° C., according to an experiment conducted by the inventors in an oxidizing atmosphere in the air, as shown in Table 7 and FIG. A heating temperature of ° C. is not sufficient. The present invention has been made in view of the above circumstances, and a method for preventing heavy metal contained in fly ash from eluting into the environment at a low cost without increasing the processing volume, and a method for preventing heavy metal elution of fly ash, and equipment and operating costs. It is an object of the present invention to provide a method for decomposing fly ash, which can decompose dioxin at a low cost and reliably.
【0004】[0004]
【課題を解決するための手段】前記目的に沿う請求項1
記載の溶融飛灰又は焼却飛灰の処理方法は、都市ゴミ及
び/又は産業廃棄物の溶融炉から発生する溶融飛灰、又
は焼却炉から発生する焼却飛灰の処理方法であって、予
め処理の対象とする前記溶融飛灰又は焼却飛灰のpHを
測定し、該測定値が11.0以上の場合、前記溶融飛灰
又は焼却飛灰を580〜800℃に加熱処理し、処理飛
灰のpHを8.5以上11.0未満にし、該処理飛灰中
の重金属の溶出を防止すると共に、該処理飛灰中に含ま
れるダイオキシンも同時に分解している。請求項2記載
の溶融飛灰又は焼却飛灰の処理方法は、都市ゴミ及び/
又は産業廃棄物の溶融炉から発生する溶融飛灰、又は焼
却炉から発生する焼却飛灰の処理方法であって、予め処
理の対象とする前記溶融飛灰又は焼却飛灰のpHを測定
し、該測定値が8.5未満の中性又は酸性の場合、予め
アルカリ源を加え、前記溶融飛灰又は焼却飛灰のpHを
一旦11.0以上にした後、次に前記溶融飛灰又は焼却
飛灰を580〜800℃に加熱処理し、処理飛灰のpH
を8.5以上11.0未満にし、該処理飛灰中の重金属
の溶出を防止すると共に、該処理飛灰中に含まれるダイ
オキシンも同時に分解している。請求項3記載の溶融飛
灰又は焼却飛灰の処理方法は、都市ゴミ及び/又は産業
廃棄物の溶融炉から発生する溶融飛灰又は焼却炉から発
生する焼却飛灰の処理方法であって、予め処理の対象と
する前記溶融飛灰又は焼却飛灰を水洗の後、水洗飛灰の
pHを測定し、該測定値が12.0以上の場合、前記水
洗飛灰を580〜800℃に加熱処理し、処理飛灰のp
Hを8.5以上11.8未満にし、該処理飛灰中の重金
属の溶出を防止すると共に、該処理飛灰中に含まれるダ
イオキシンも同時に分解している。そして、請求項4記
載の溶融飛灰又は焼却飛灰の処理方法は、都市ゴミ及び
/又は産業廃棄物の溶融炉から発生する溶融飛灰又は焼
却炉から発生する焼却飛灰の処理方法であって、予め処
理の対象とする前記溶融飛灰又は焼却飛灰を水洗の後、
水洗飛灰のpHを測定し、該測定値が8.5未満の中性
又は酸性の場合、予めアルカリ源を加え、前記水洗飛灰
のpHを一旦12.0以上にした後、次に前記水洗飛灰
を580〜800℃に加熱処理し、処理飛灰のpHを
8.5以上11.8未満にし、該処理飛灰中の重金属の
溶出を防止すると共に、該処理飛灰中に含まれるダイオ
キシンも同時に分解している。According to the present invention, there is provided a semiconductor device comprising:
The method for treating molten fly ash or incinerated fly ash described above is a method for treating molten fly ash generated from a melting furnace for municipal waste and / or industrial waste or incinerated fly ash generated from an incinerator. The pH of the molten fly ash or incinerated fly ash to be measured is measured, and when the measured value is 11.0 or more, the molten fly ash or the incinerated fly ash is heated to 580 to 800 ° C. Is adjusted to 8.5 or more and less than 11.0 to prevent elution of heavy metals in the treated fly ash, and dioxin contained in the treated fly ash is also decomposed at the same time. The method for treating molten fly ash or incinerated fly ash according to claim 2 is characterized in that
Or a method of treating molten fly ash generated from a melting furnace of industrial waste, or incinerated fly ash generated from an incinerator, measuring the pH of the molten fly ash or incinerated fly ash to be treated in advance, When the measured value is less than 8.5 neutral or acidic, an alkali source is added in advance to adjust the pH of the molten fly ash or incinerated fly ash to 11.0 or more, and then the molten fly ash or incinerated Heat treatment of fly ash to 580-800 ° C, pH of treated fly ash
Is set to 8.5 or more and less than 11.0 to prevent elution of heavy metals in the treated fly ash, and dioxin contained in the treated fly ash is also decomposed. The method for treating molten fly ash or incinerated fly ash according to claim 3 is a method for treating molten fly ash generated from a melting furnace for municipal garbage and / or industrial waste or incinerated fly ash generated from an incinerator. After the molten fly ash or incinerated fly ash to be treated in advance is washed with water, the pH of the washed fly ash is measured, and when the measured value is 12.0 or more, the washed fly ash is heated to 580 to 800 ° C. Treated and treated fly ash p
H is set to 8.5 or more and less than 11.8 to prevent elution of heavy metals in the treated fly ash, and dioxin contained in the treated fly ash is also decomposed at the same time. The method for treating molten fly ash or incinerated fly ash according to claim 4 is a method for treating molten fly ash produced from a melting furnace for municipal waste and / or industrial waste or incinerated fly ash produced from an incinerator. Then, after washing the molten fly ash or incinerated fly ash to be treated in advance,
The pH of the washed fly ash is measured, and when the measured value is neutral or acidic, less than 8.5, an alkali source is added in advance to adjust the pH of the washed fly ash to 12.0 or more, and then the The washed fly ash is heat-treated at 580 to 800 ° C. to adjust the pH of the treated fly ash to 8.5 or more and less than 11.8, to prevent elution of heavy metals in the treated fly ash and to be included in the treated fly ash. Dioxin is also decomposed at the same time.
【0005】溶融飛灰とは、都市ゴミ及び/又は産業廃
棄物を溶融炉で処理するに際して、この溶融炉から発生
する排ガスに随伴される灰であり、焼却飛灰とは、都市
ゴミ及び/又は産業廃棄物を焼却炉で処理するに際し
て、この焼却炉から発生する排ガスに随伴される灰であ
って、いずれも、排ガスと共に排出される比較的粒径の
小さい粒子を集塵機等で捕集したものからなる。一方、
焼却灰の内で焼却炉の炉底等に溜まるものを主灰とい
う。溶融飛灰又は焼却飛灰(以下、再び単に飛灰と呼
ぶ)、及びこれら飛灰が処理された中間の水洗飛灰及び
最終の処理飛灰のpHとは、環境庁告示第13号試験法
に定められた方法により測定されるpHの測定値であ
り、所定量の試料を所定量の水に所定条件の下で浸漬さ
せて、その浸漬液中の水素イオン濃度を測定することに
より得られる。pHが11.0以上となる飛灰(アルカ
リ飛灰)を加熱処理することで飛灰中のCa(OH)2
の約580℃での脱水反応(1)、CaOとSiO2 の
カルシウムシリケートの生成反応((2)、(3)、
(4))、Na2 OとSiO2 及びAl2 O3 との生成
反応((5)〜(9))、K2 OとSiO2 及びAl2
O3 との生成反応((10)〜(14))、MgOとC
aO及びSiO2 との生成反応等が生じ、安定な化合物
を生じることで飛灰中のフリーなアルカリ源(CaO、
Na2 O、K2 O、MgO)の量を減少させることがで
きる。[0005] Melt fly ash is ash accompanying exhaust gas generated from a melting furnace when municipal waste and / or industrial waste is treated in a melting furnace. Or, when treating industrial waste in an incinerator, ash accompanying exhaust gas generated from the incinerator, and in each case, particles having a relatively small particle size discharged together with the exhaust gas were collected by a dust collector or the like. Consist of things. on the other hand,
The incineration ash that accumulates at the bottom of the incinerator is called main ash. The pH of the molten fly ash or incinerated fly ash (hereinafter, simply referred to as fly ash), and the pH of the intermediate fly ash and the final treated fly ash that have been treated with these fly ash are the Test Method No. 13 of the Notification of the Environment Agency Is a measured value of pH measured by the method defined in the above, obtained by immersing a predetermined amount of sample in a predetermined amount of water under predetermined conditions, and measuring the hydrogen ion concentration in the immersion liquid . Heat treatment of fly ash (alkaline fly ash) having a pH of 11.0 or more causes Ca (OH) 2 in fly ash
Dehydration reaction at about 580 ° C (1), formation reaction of calcium silicate of CaO and SiO2 ((2), (3),
(4)), formation reaction of Na2 O with SiO2 and Al2 O3 ((5) to (9)), K2 O with SiO2 and Al2
Formation reaction with O3 ((10) to (14)), MgO and C
A production reaction with aO and SiO2 occurs, and a stable compound is produced, so that a free alkali source (CaO,
Na2 O, K2 O, MgO) can be reduced.
【0006】 (1)Ca(OH)2 →CaO+H2 O (2)CaO+SiO2 →CaO・SiO2 (3)2CaO+SiO2 →2CaO・SiO2 (4)3CaO+2SiO2 →3CaO・2SiO2 (5)Na2 O+SiO2 →Na2 O・SiO2 (6)Na2 O+2SiO2 →Na2 O・2SiO2 (7)2Na2 O+SiO2 →2Na2 O・SiO2 (8)Na2 O+Al2 O3 +6SiO2 →Na2 O・
Al2 O3 ・6SiO2 (9)Na2 O+Al2 O3 +2SiO2 →Na2 O・
Al2 O3 ・2SiO2 (10)K2 O+SiO2 →K2 O・SiO2 (11)K2 O+2SiO2 →K2 O・2SiO2 (12)K2 O+4SiO2 →K2 O・4SiO2 (13)K2 O+Al2 O3 +2SiO2 →K2 O・A
l2 O3 ・2SiO2 (14)K2 O+Al2 O3 +6SiO2 →K2 O・A
l2 O3 ・6SiO2 ここで飛灰を加熱処理する際の加熱温度が580℃より
低いと、前記(1)〜(14)の反応を起こさせること
が困難になる。逆に、飛灰の加熱温度が800℃より高
くなると、重金属、金属塩化物等が蒸発して二次汚染の
原因となり、排ガス処理が別途必要となるので好ましく
ない。(1) Ca (OH) 2 → CaO + H 2 O (2) CaO + SiO 2 → CaO.SiO 2 (3) 2CaO + SiO 2 → 2CaO.SiO 2 (4) 3CaO + 2SiO 2 → 3CaO.2SiO 2 (5) Na 2 O + SiO 2 → Na 2 O.SiO 2 (6 Na2O + 2SiO2 → Na2O.2SiO2 (7) 2Na2O + SiO2 → 2Na2O.SiO2 (8) Na2O + Al2O3 + 6SiO2 → Na2O.
Al2 O3 .6SiO2 (9) Na2 O + Al2 O3 + 2SiO2 → Na2 O.
Al2 O3 .2SiO2 (10) K2 O + SiO2 → K2 O.SiO2 (11) K2 O + 2SiO2 → K2 O.2SiO2 (12) K2 O + 4SiO2 → K2 O.4SiO2 (13) K2O + Al2 O3 + 2SiO2 → K2 O.A
l2 O3 · 2SiO2 (14) K2 O + Al2 O3 + 6 SiO2 → K2 O · A
l2 O3 .6SiO2 If the heating temperature at the time of heat-treating the fly ash is lower than 580 DEG C., it becomes difficult to cause the reactions (1) to (14). Conversely, if the heating temperature of the fly ash is higher than 800 ° C., heavy metals, metal chlorides, etc. evaporate, causing secondary pollution, which requires an exhaust gas treatment, which is not preferable.
【0007】飛灰を加熱処理して得られる処理飛灰のp
Hが8.5より低いと、鉛等の重金属イオンの溶出量を
増加させる。また、処理飛灰のpHが11.0以上とな
ってもこの溶出量を増加させる要因となる。水洗飛灰を
加熱処理して得られる処理飛灰の場合には、その処理飛
灰のpH値が8.5より低く、また、逆に11.8以上
となると重金属の溶出濃度を増加させる要因となるので
好ましくない。[0007] The p of the treated fly ash obtained by heat-treating the fly ash
If H is lower than 8.5, the elution amount of heavy metal ions such as lead increases. In addition, even if the pH of the treated fly ash becomes 11.0 or more, it becomes a factor to increase this elution amount. In the case of the treated fly ash obtained by heat-treating the washed fly ash, the pH value of the treated fly ash is lower than 8.5, and conversely, when the pH value of the treated fly ash is 11.8 or more, the concentration of heavy metal dissolved increases. Is not preferred.
【0008】処理飛灰を浸水させたときに溶出する重金
属の溶出量(溶出濃度)は、(1)処理飛灰を水に浸漬
し攪拌して得られるpH値、及び(2)処理飛灰中の水
溶性塩化物の濃度によって決定される。 (1)Pb、Cd、Zn、Cr等の重金属成分溶出は、
このpH値との依存性が高く、pH値によりその溶出量
が決定される。 (2)飛灰中の塩化鉛等の水溶性の重金属塩化物の存在
により、重金属酸化物、水酸化物の溶解度積を増加さ
せ、重金属の溶出濃度を上げる。 飛灰のpH値は、遊離した状態にあるCaOもしくは、
Ca(OH)2 の濃度により決定され、少量存在しただ
けでもpH値は12以上のアルカリ性を示すことにな
る。例えば、pH依存性が大きく、飛灰中に多く存在す
る鉛(Pb)はこのpH値によりその溶出量が決定され
るといっても過言ではない。The elution amount (elution concentration) of heavy metal eluted when the treated fly ash is submerged is as follows: (1) pH value obtained by immersing the treated fly ash in water and stirring; Determined by the concentration of the water-soluble chloride in it. (1) Elution of heavy metal components such as Pb, Cd, Zn, and Cr
The elution amount is highly dependent on the pH value, and the elution amount is determined by the pH value. (2) Due to the presence of water-soluble heavy metal chlorides such as lead chloride in fly ash, the solubility product of heavy metal oxides and hydroxides is increased, and the elution concentration of heavy metals is increased. The pH value of fly ash is CaO in the free state or
The pH value is determined by the concentration of Ca (OH) 2, and even if present in a small amount, the pH value indicates an alkalinity of 12 or more. For example, it is not an exaggeration to say that the elution amount of lead (Pb), which has a large pH dependence and is abundant in fly ash, is determined by this pH value.
【0009】本発明は、Ca(OH)2 、CaO分等の
ライム分を含む飛灰を特定の温度範囲で加熱処理するこ
とで、Ca(OH)2 の脱水反応(580℃以上)によ
り活性の高いCaOを生成させ、CaOとSiO2 等の
生成反応を促進させる。また、加熱処理によりアルカリ
金属及びアルカリ土類金属酸化物(Na2 O、K2 O、
MgO等)の活性が高くなり、SiO2 等との生成反応
が生じる。これにより遊離状態にあるアルカリ源である
CaO、Na2 O、K2 O、MgO等がSiO2 、Al
2 O3 等と反応し、捕捉固定化され、水に浸漬させたと
きのpH値を所定範囲に維持して重金属の溶出を防止す
ることができる。また、飛灰を水洗した後に、この水洗
飛灰を加熱処理することで処理飛灰からの重金属の溶出
防止をさらに効果的に図ることができる。即ち、飛灰を
水洗することで水溶性の重金属塩化物等が予め除去され
ているので、この乾燥した、あるいは少量の水分を含む
水洗飛灰を加熱処理すれば、重金属の溶出防止を更に効
率的に行うことができる。According to the present invention, fly ash containing lime such as Ca (OH) 2 and CaO is heated in a specific temperature range to activate by a dehydration reaction (580 ° C. or more) of Ca (OH) 2. To generate CaO having a high concentration, thereby promoting the reaction of generating CaO and SiO2. In addition, alkali metal and alkaline earth metal oxides (Na2O, K2O,
(MgO etc.) becomes active, and a formation reaction with SiO2 etc. occurs. As a result, CaO, Na2 O, K2 O, MgO, etc., which are free alkali sources, are converted into SiO2, Al
It reacts with 2 O3 and the like, is captured and fixed, and can maintain the pH value when immersed in water in a predetermined range to prevent elution of heavy metals. In addition, after the fly ash is washed with water, heat treatment of the washed fly ash can further effectively prevent the elution of heavy metals from the treated fly ash. That is, since the water-soluble heavy metal chlorides and the like have been removed in advance by washing the fly ash with water, heat treatment of the dried or washed fly ash containing a small amount of water can further prevent the elution of heavy metals. Can be done
【0010】また、飛灰が空気中の酸化雰囲気において
580℃以上という高温で加熱処理されるので、ダイオ
キシンを分解して無害化する効果も得られる。また、最
近では、排ガス中のダイオキシン吸着のため活性コーク
スや活性炭等の粉末吸着剤を吹込んでいる例があり、発
生する飛灰中にはこの活性コークスや活性炭等が含まれ
る場合がある。これら活性コークスや活性炭の発火有無
は雰囲気温度はもちろん、堆積状態、通風の状況等、周
囲の環境に大きく影響されるが、発明者らの実験によれ
ば、今回の580℃以上の加熱温度であれば短時間でも
確実に着火燃焼することが確認されている。通常、この
粉末吸着剤は飛灰の量に対して3%程度の量が吹込まれ
るのでこれらが全量発火しCO2 になったと仮定した
ら、飛灰としてはおよそ100℃程度の昇温となる。
(着熱効率を上記実験結果より仮定した。)従ってこの
分加熱用の熱量の低減が図れる。また、当然この粉末吸
着剤には多量のダイオキシンが吸着捕捉されているが、
飛灰の加熱と共にこれらのダイオキシンも同様に分解
し、無害化される。Further, since fly ash is heated at a high temperature of 580 ° C. or more in an oxidizing atmosphere in the air, an effect of decomposing dioxin and rendering it harmless is also obtained. Also, recently, powder adsorbents such as activated coke and activated carbon have been blown to adsorb dioxins in exhaust gas, and the fly ash generated may contain such activated coke and activated carbon. The presence or absence of ignition of these activated coke and activated carbon is greatly affected not only by the ambient temperature but also by the surrounding environment, such as the deposition state and the state of ventilation, but according to experiments by the inventors, at the current heating temperature of 580 ° C. or more, It has been confirmed that ignition and combustion can be ensured even in a short time. Usually, the powder adsorbent is injected in an amount of about 3% with respect to the amount of fly ash, so that assuming that all of the fire ignites to CO2, the temperature of the fly ash rises by about 100 ° C.
(The heat transfer efficiency was assumed based on the above experimental results.) Therefore, the amount of heat for heating can be reduced accordingly. Also, naturally, a large amount of dioxin is adsorbed and captured in this powder adsorbent,
These dioxins are similarly decomposed and rendered harmless by the heating of the fly ash.
【0011】[0011]
【発明の実施の形態】続いて、添付した図面を参照しつ
つ、本発明を具体化した実施の形態につき説明し、本発
明の理解に供する。図1は本発明の第1の実施の形態に
係る溶融飛灰又は焼却飛灰の処理方法を適用する飛灰処
理装置10の説明図であり、飛灰処理装置10は窒素ガ
ス13を入れる状態もしくは窒素ガス中で飛灰11を加
熱処理して処理飛灰14を得るための高温処理炉15を
有している。本発明の第1の実施の形態に係る溶融飛灰
又は焼却飛灰の処理方法について以下、説明する。飛灰
11を窒素ガス13を使用しないで、もしくは窒素ガス
を使用して高温処理炉15に送入して、所定の加熱温度
580〜800℃で所定の加熱時間例えば15〜240
分間加熱して処理飛灰14を得ることができる。DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. FIG. 1 is an explanatory view of a fly ash treatment device 10 to which a method for treating molten fly ash or incinerated fly ash according to a first embodiment of the present invention is used. Alternatively, a high-temperature processing furnace 15 for heating the fly ash 11 in a nitrogen gas to obtain the treated fly ash 14 is provided. The method for treating molten fly ash or incinerated fly ash according to the first embodiment of the present invention will be described below. The fly ash 11 is fed into the high-temperature processing furnace 15 without using the nitrogen gas 13 or using the nitrogen gas, and is heated at a predetermined heating temperature of 580 to 800 ° C. for a predetermined heating time, for example, 15 to 240.
The heated fly ash 14 can be obtained by heating for minutes.
【0012】この加熱時間は、間接加熱、直接加熱等の
加熱方式、加熱装置の構造、及び加熱能力等により種々
変化する。要するに処理対象とする飛灰の全てをいかに
して所定の温度範囲内に昇温させるかで設定される。例
えば、加熱処理中に飛灰を攪拌することにより加熱処理
時間を短縮することができる。The heating time varies depending on the heating method such as indirect heating or direct heating, the structure of the heating device, the heating capacity, and the like. In short, it is set by how to raise the temperature of all the fly ash to be treated within a predetermined temperature range. For example, the heat treatment time can be shortened by stirring the fly ash during the heat treatment.
【0013】また、最近では排ガス中の酸性ガスを除去
するために、溶融炉又は焼却炉からの排ガスに消石灰を
吹込んでいるので、発生する飛灰はアルカリ性となる場
合が殆どであるが、旧式の焼却炉等では消石灰の吹込み
を実施していない場合もあるため、飛灰は酸性もしくは
中性の飛灰となっている。このpH値が約6〜8程度の
酸性もしくは8.5未満の中性飛灰では、これらを水に
浸漬させた場合の重金属の溶出濃度が大きくなる。従っ
て、飛灰11のpH値がこのように低い場合には、アル
カリ源、例えばCa(OH)2 を飛灰11に対して5〜
10wt%程度を混合して、一旦、pH値が11.0以
上のアルカリ側に移行させた後、同様に加熱処理するこ
とで処理飛灰のpH値を8.5〜11.0の範囲に低下
させ、重金属の溶出防止を図ることができる。更に、処
理の対象とする飛灰11を予め水洗した場合のpH値が
6〜8程度のときにも、同様にアルカリ源を飛灰11と
混合させ、一旦、pH値が12.0以上のアルカリ側に
移行させた後、加熱処理することでpH値を8.5〜1
1.8の範囲に低下させることにより重金属の溶出を効
果的に防止できる。以下、これらの実施例1〜3につい
て表を引用しながら具体的に説明する。Recently, slaked lime is blown into exhaust gas from a melting furnace or an incinerator in order to remove acidic gas in the exhaust gas, so that fly ash generated is almost always alkaline. In some incinerators, slaked lime is not injected, so fly ash is acidic or neutral fly ash. In the case of an acidic fly ash having a pH value of about 6 to 8 or a neutral fly ash of less than 8.5, the elution concentration of heavy metals when these are immersed in water increases. Accordingly, when the pH value of the fly ash 11 is so low, an alkali source, for example, Ca (OH) 2,
About 10 wt% is mixed, and once the pH value is shifted to the alkali side of 11.0 or more, the same heat treatment is performed to adjust the pH value of the treated fly ash to a range of 8.5 to 11.0. And the elution of heavy metals can be prevented. Further, even when the pH value of the fly ash 11 to be treated is about 6 to 8 when the fly ash 11 is previously washed with water, the alkali source is similarly mixed with the fly ash 11 and once the pH value is 12.0 or more. After being shifted to the alkali side, the pH value is adjusted to 8.5 to 1 by heat treatment.
By reducing the content to the range of 1.8, elution of heavy metals can be effectively prevented. Hereinafter, Examples 1 to 3 will be specifically described with reference to tables.
【0014】(実施例1)表2は、表1に示す組成の飛
灰11を300℃、400℃、500℃、600℃、7
00℃の加熱温度でそれぞれ15分間加熱処理して得ら
れる処理飛灰のpH値と重金属溶出濃度との関係を示し
ている。また、図2には、これらの関係をグラフに示し
た。Example 1 Table 2 shows that fly ash 11 having the composition shown in Table 1 was prepared at 300 ° C., 400 ° C., 500 ° C., 600 ° C., and 7 ° C.
The relationship between the pH value of the treated fly ash obtained by heating each at a heating temperature of 00 ° C. for 15 minutes and the heavy metal elution concentration is shown. FIG. 2 is a graph showing these relationships.
【0015】[0015]
【表1】 [Table 1]
【0016】[0016]
【表2】 [Table 2]
【0017】表2及び図2に示されるように、加熱温度
が600℃付近になるとpH値が急激に減少し、重金属
(Pb、Zn、Cd)の溶出濃度も同様に急激に低下し
ていることが分かる。これは前述のように、Ca(O
H)2 の脱水反応温度の580℃を超えた時点でフリー
CaO分がSiO2 等との生成反応を促進したためであ
る。ここで、飛灰の成分変動が大きいことや加熱処理時
のムラ焼等を考慮すると加熱処理温度は好ましくは60
0℃以上とするのがよい。As shown in Table 2 and FIG. 2, when the heating temperature is around 600 ° C., the pH value sharply decreases, and the elution concentration of heavy metals (Pb, Zn, Cd) also sharply decreases. You can see that. This is, as described above, Ca (O
This is because the free CaO component promoted the formation reaction with SiO2 and the like when the dehydration reaction temperature of H) 2 exceeded 580 ° C. Here, the heat treatment temperature is preferably 60 in consideration of large fluctuations in the components of fly ash and uneven burning during the heat treatment.
The temperature is preferably set to 0 ° C. or higher.
【0018】(実施例2)表3に示す実施例2は、前記
実施例1と同じく表1に示す組成の飛灰11を用いた別
の実験例であって、加熱温度を600℃とし、処理時間
を15分、40分、60分とそれぞれ変化させ、このよ
うに加熱処理して得られる処理飛灰のpH値と鉛溶出濃
度との関係を示している。(Example 2) Example 2 shown in Table 3 is another experimental example using fly ash 11 having the composition shown in Table 1 as in Example 1 described above. The treatment time was changed to 15 minutes, 40 minutes, and 60 minutes, respectively, and the relationship between the pH value and the lead elution concentration of the treated fly ash obtained by heat treatment in this manner is shown.
【0019】[0019]
【表3】 [Table 3]
【0020】この場合の飛灰11のpH値は12.4
1、鉛溶出濃度は359ppmであったものが、処理飛
灰のpH値を10.47〜10.67に低下させると共
に、鉛溶出濃度を環境基準(埋立処分場にて0.3pp
m以下)を満足する0.1〜0.17ppmに抑制する
ことができるのが分かる。また、加熱時間を長くしても
pH値と溶出値とが安定していることが分かる。In this case, the pH value of the fly ash 11 is 12.4.
1. Although the lead elution concentration was 359 ppm, the pH value of the treated fly ash was lowered to 10.47 to 10.67, and the lead elution concentration was set to environmental standards (0.3 pp at the landfill site).
m or less) can be suppressed to 0.1 to 0.17 ppm, which satisfies the following condition. Also, it can be seen that the pH value and the elution value are stable even when the heating time is lengthened.
【0021】(実施例3)次に、例えば旧式の焼却炉の
排ガス中に消石灰を吹き込まない場合に発生する酸性飛
灰の成分の一例を表4に示す。表5の(1)に示すよう
に加熱処理していない場合の飛灰のpH値は6.23と
低くなって、鉛の溶出濃度は31ppmと環境基準を大
きく上回っている。一方、表5の(2)に示すように飛
灰にCa(OH)2 を5wt%添加した場合のpH値は
12.53でありPb溶出濃度も122ppmと高い。
しかし表5の(3)に示すように、これを600℃、2
0分にて加熱処理すればpH値が10.68となり、P
b溶出濃度は環境基準を下回る0.15ppmとするこ
とが可能となる。(Example 3) Next, Table 4 shows an example of the components of acidic fly ash generated when slaked lime is not blown into the exhaust gas of an old incinerator. As shown in (1) of Table 5, the pH value of the fly ash when not subjected to the heat treatment is as low as 6.23, and the elution concentration of lead is 31 ppm, which is much higher than the environmental standard. On the other hand, as shown in (2) of Table 5, when 5 wt% of Ca (OH) 2 is added to fly ash, the pH value is 12.53, and the Pb elution concentration is as high as 122 ppm.
However, as shown in (3) of Table 5, this was carried out at 600 ° C. for 2 hours.
If heat treatment is performed at 0 minutes, the pH value becomes 10.68, and P
b The elution concentration can be 0.15 ppm, which is lower than the environmental standard.
【0022】[0022]
【表4】 [Table 4]
【0023】[0023]
【表5】 [Table 5]
【0024】次にダイオキシン分解についての実施例4
を示す。 (実施例4)Next, Example 4 concerning dioxin decomposition
Is shown. (Example 4)
【0025】[0025]
【表6】 [Table 6]
【0026】[0026]
【表7】 [Table 7]
【0027】表7は表6に示す組成の飛灰を450℃、
550℃、650℃の加熱温度でそれぞれ30分間空気
中の酸化雰囲気で加熱処理して得られた処理飛灰のダイ
オキシン濃度を示している。また、図3には、これらの
関係をグラフに示した。ところで、「ごみ処理に係るダ
イオキシン類発生防止等ガイドライン/平成9年1月発
行(以下、新ガイドラインと呼ぶ)」において、ごみ処
理施設から発生するダイオキシンの排出総量値5μg−
TEQ/ごみtonが参考値として設定され、それを実
現するための各排出物の濃度が焼却炉を前提として以下
のように試算されている。 (1)排ガス 5000Nm3 /ごみton×0.1ng−TEQ/Nm3 =0.5μg−TEQ/ごみton (2)焼却灰 150kg/ごみton×0.01ng/g−TEQ =1.5μg−TEQ/ごみton (3)飛灰 30kg/ごみton×0.1ng/g−TEQ =3.0μg−TEQ/ごみton 合計 5.0μg−TEQ/ごみtonTable 7 shows fly ash having the composition shown in Table 6 at 450 ° C.
The dioxin concentration of the treated fly ash obtained by performing the heat treatment in an oxidizing atmosphere in the air at a heating temperature of 550 ° C. and 650 ° C. for 30 minutes each is shown. FIG. 3 is a graph showing these relationships. By the way, in the “Guidelines on Prevention of Dioxin Generation Related to Waste Disposal / Issued in January 1997 (hereinafter referred to as new guidelines)”, the total emission of dioxins generated from waste treatment facilities is 5 μg-
TEQ / garbage ton is set as a reference value, and the concentration of each emission to achieve it is calculated as follows on the assumption of an incinerator. (1) Exhaust gas 5000 Nm3 / garbage ton x 0.1 ng-TEQ / Nm3 = 0.5 g-TEQ / garbage ton (2) Incineration ash 150 kg / garbage ton x 0.01 ng / g-TEQ = 1.5 g-TEQ / garbage ton (3) Fly ash 30 kg / garbage ton × 0.1 ng / g-TEQ = 3.0 μg-TEQ / garbage ton Total 5.0 μg-TEQ / garbage ton
【0028】今、表7及び図3を見ると加熱温度550
℃で上記試算値と全く同じ0.1ng/g−TEQとな
っているが、当然飛灰の組成によってはこの値は上、下
に変化し飛灰の種類により、前記の排出総量参考値を満
足できない場合も生ずる。従って550℃の加熱温度で
はダイオキシン分解に対しては不充分であり、それ以上
の温度が必要となる。図3によると加熱温度550℃を
すぎたあたりから、ダイオキシン濃度は急激に減少して
おり580℃では0.05ng/g−TEQまで低減し
ている。このように、例え、空気中の酸化雰囲気であっ
ても580℃以上に加熱すれば飛灰の種類による低減度
合の差を考慮してもダイオキシンの分解は、確実なもの
になることがわかる。前述した重金属の加熱処理を考え
合わせると、飛灰の重金属溶出防止、ダイオキシン分解
を同時に享受するためには、加熱温度としては580℃
以上が必要となる訳である。図4は本発明の第2の実施
の形態に係る溶融飛灰又は焼却飛灰の処理方法を適用す
る飛灰処理装置20の説明図であり、飛灰処理装置20
は飛灰21と水とを混合するための攪拌羽根を備えた混
合機22と、混合機22で洗浄処理された懸濁水を水洗
飛灰23と処理水24とに分離し、処理水24を水処理
設備25に供給するための濾過装置26と、水洗飛灰2
3を窒素ガスを含まない雰囲気中もしくは窒素ガス中で
加熱処理して処理飛灰28を得るための高温処理炉29
を有している。Now, referring to Table 7 and FIG.
Although it is 0.1 ng / g-TEQ which is exactly the same as the above calculated value at ℃, depending on the composition of the fly ash, this value changes up and down. In some cases, it is not satisfactory. Therefore, a heating temperature of 550 ° C. is insufficient for dioxin decomposition, and a higher temperature is required. According to FIG. 3, the dioxin concentration sharply decreases after the heating temperature exceeds 550 ° C., and decreases to 0.05 ng / g-TEQ at 580 ° C. Thus, it can be seen that, even in an oxidizing atmosphere in the air, heating to 580 ° C. or more can reliably decompose dioxin even if the difference in the degree of reduction depending on the type of fly ash is considered. Considering the above-described heat treatment of heavy metals, in order to prevent heavy metal elution of fly ash and to simultaneously decompose dioxin, the heating temperature should be 580 ° C.
The above is necessary. FIG. 4 is an explanatory view of a fly ash processing apparatus 20 to which a method for processing molten fly ash or incinerated fly ash according to the second embodiment of the present invention is used.
Is a mixer 22 having a stirring blade for mixing the fly ash 21 and water, and the suspended water washed by the mixer 22 is separated into a washed fly ash 23 and a treated water 24, and the treated water 24 is separated. A filtration device 26 for supplying to the water treatment equipment 25;
3 is subjected to a heat treatment in an atmosphere containing no nitrogen gas or in a nitrogen gas to obtain a processing fly ash 28.
have.
【0029】続いて、本発明の第2の実施の形態に係る
溶融飛灰又は焼却飛灰の処理方法について説明する。ま
ず、図示しない溶融炉又は焼却炉から採取された飛灰2
1と水とを混合機22で所定時間、例えば10〜30分
間攪拌洗浄することにより飛灰21中の塩化鉛、塩化ナ
トリウム、塩化カリウム、塩化カルシウム等の水溶性塩
化物を溶出させ、これによって処理物(処理飛灰28)
を水に浸漬させた際の重金属の溶出を効果的に抑制する
ことができる。次に、この混合機22で混合された処理
液を濾過装置26で濾過し、固形分である水洗飛灰23
を高温処理炉29に送入し、窒素ガスを使用しない雰囲
気中か、もしくは窒素ガスを使用する雰囲気中、所定の
加熱温度580〜800℃で所定の時間例えば15〜2
40分間、好ましくは20〜180分間加熱して処理飛
灰28を得ることができる。なお、加熱処理における雰
囲気は、空気中の酸化雰囲気、窒素ガス中における不活
性ガス雰囲気の他に、水素ガス中等の還元雰囲気であっ
てもよい。一方、濾過装置26から分離排出される処理
水24は水処理設備25において適正な処理をした後、
系外に排出するようになっている。Next, a method for treating molten fly ash or incinerated fly ash according to a second embodiment of the present invention will be described. First, fly ash 2 collected from a melting furnace or an incinerator (not shown)
The water-soluble chlorides such as lead chloride, sodium chloride, potassium chloride and calcium chloride in the fly ash 21 are eluted by stirring and washing the mixture 1 and water with the mixer 22 for a predetermined time, for example, 10 to 30 minutes. Processed material (processed fly ash 28)
Elution of heavy metals when immersed in water can be effectively suppressed. Next, the treatment liquid mixed by the mixer 22 is filtered by a filtration device 26, and the washed fly ash 23, which is a solid content, is removed.
Into the high-temperature processing furnace 29, in an atmosphere in which nitrogen gas is not used, or in an atmosphere in which nitrogen gas is used, at a predetermined heating temperature of 580 to 800 ° C. for a predetermined time, for example, 15 to 2 hours.
The heated fly ash 28 can be obtained by heating for 40 minutes, preferably for 20 to 180 minutes. Note that the atmosphere in the heat treatment may be a oxidizing atmosphere in air, an inert gas atmosphere in nitrogen gas, or a reducing atmosphere such as hydrogen gas. On the other hand, after the treated water 24 separated and discharged from the filtration device 26 is properly treated in the water treatment facility 25,
It is designed to be discharged out of the system.
【0030】このように、第2の実施の形態に係る溶融
飛灰又は焼却飛灰の処理方法は、予め水洗処理され、水
溶性の重金属塩化物等の除去された水洗飛灰23に所定
温度条件の加熱処理を行うので、この加熱処理された処
理飛灰28を水等に浸漬させた際の重金属の溶出を更に
効果的に抑制できる。この実施例5について説明する。As described above, in the method for treating molten fly ash or incinerated fly ash according to the second embodiment, a predetermined temperature is applied to the washed fly ash 23 which has been subjected to a water washing treatment and from which water-soluble heavy metal chlorides and the like have been removed. Since the heat treatment under the conditions is performed, the elution of heavy metal when the heat-treated fly ash 28 is immersed in water or the like can be more effectively suppressed. Example 5 will be described.
【0031】(実施例5)表8の実施例5は、前記実施
例1と同じく表1に示す組成の飛灰21を予め水洗、脱
水して、これを水洗飛灰23とした後、前記実施例2と
同じ加熱温度である600℃として設定し、加熱時間を
15分、40分間としてそれぞれ変化させて得られる処
理飛灰28のデータを示している。この場合の水洗飛灰
23のpH値が12.53、鉛溶出濃度が47.7pp
mであったものが、処理飛灰28のpH値を11.52
〜11.65に低下させると共に、鉛溶出濃度を環境基
準を満足する0.1〜0.18ppmに抑制できること
が分かる。(Example 5) In Example 5 of Table 8, fly ash 21 having the composition shown in Table 1 was washed and dehydrated in advance in the same manner as in Example 1 to obtain washed fly ash 23. The data of the treated fly ash 28 obtained by setting the same heating temperature as in Example 2 at 600 ° C. and changing the heating time to 15 minutes and 40 minutes, respectively, are shown. In this case, the pH value of the washed fly ash 23 was 12.53, and the lead elution concentration was 47.7 pp.
m, the pH value of the treated fly ash 28 was changed to 11.52.
It can be seen that the lead elution concentration can be suppressed to 0.1 to 0.18 ppm, which satisfies environmental standards, while reducing the concentration to 11.65 ppm.
【0032】[0032]
【表8】 [Table 8]
【0033】以上、本発明の実施の形態を説明したが、
本発明はこれらの実施の形態に限定されるものではな
く、要旨を逸脱しない条件の変更等は全て本発明の適用
範囲である。例えば、本実施の形態おいては、アルカリ
源として消石灰を添加して、飛灰のpH値を調整する方
法について述べたが、消石灰以外の例えばCaO等を用
いることも可能である。The embodiment of the present invention has been described above.
The present invention is not limited to these embodiments, and all changes in conditions without departing from the gist are within the scope of the present invention. For example, in the present embodiment, the method of adjusting the pH value of fly ash by adding slaked lime as an alkali source has been described, but it is also possible to use CaO or the like other than slaked lime.
【0034】[0034]
【発明の効果】請求項1〜4記載の溶融飛灰又は焼却飛
灰の処理方法においては、特定pH値となる飛灰を所定
温度に加熱処理して、処理飛灰のpH値を所定範囲にす
ることにより、飛灰中に遊離しているアルカリ源である
CaO、Na2 O、K2 O、MgO等をSiO2 、Al
2 O3 等と反応させて安定化させる。これによって、水
に浸漬させた時のpH値の増加を抑制でき、処理飛灰に
含まれる重金属の溶出が防止される。飛灰に薬剤、セメ
ントを添加して重金属の溶出を防止する方法、及び飛灰
から酸液により重金属を抽出させる方法では、いずれも
コスト的に高価となり処理後の容積が大きくなるが、本
法では安価にかつ、処理容積を増やすことなく処理飛灰
中に含まれる重金属の溶出を防止できる。特に、請求項
3及び4記載の溶融飛灰又は焼却飛灰の処理方法におい
ては、飛灰は予め水洗されるので、水溶性の重金属塩化
物等が除去され、さらに効果的に重金属の溶出防止が図
られる。一方、重金属溶出防止処理における飛灰の58
0℃以上の加熱により例え、空気中の酸化雰囲気下であ
っても、ダイオキシンは、「新ガイドライン」に示され
た排出総量参考値のうちの飛灰濃度0.1ng/g−T
EQを大幅に下回るレベルまで確実に低減されるため、
酸素欠乏状態(還元雰囲気)にするための特別な構造、
装置も不要で、装置は安価となる。また、不活性ガス等
の費用も不要となる。According to the method for treating molten fly ash or incinerated fly ash according to the present invention, the fly ash having a specific pH value is heat-treated to a predetermined temperature to adjust the pH value of the treated fly ash to a predetermined range. In this way, CaO, Na2 O, K2 O, MgO, etc., which are the alkali sources released in the fly ash, are converted into SiO2, Al
Stabilize by reacting with 2 O3 etc. Thereby, an increase in pH value when immersed in water can be suppressed, and elution of heavy metals contained in the treated fly ash can be prevented. The methods of adding chemicals and cement to fly ash to prevent the elution of heavy metals and the method of extracting heavy metals from fly ash with an acid solution are both costly and increase the volume after treatment. Thus, elution of heavy metals contained in the processing fly ash can be prevented at low cost and without increasing the processing volume. In particular, in the method for treating molten fly ash or incinerated fly ash according to the third and fourth aspects, since the fly ash is washed in advance with water, water-soluble heavy metal chlorides and the like are removed, and the elution of heavy metals is more effectively prevented. Is achieved. On the other hand, fly ash 58 in the heavy metal elution prevention treatment
Even under heating at 0 ° C. or higher, even under an oxidizing atmosphere in the air, dioxin is found to have a fly ash concentration of 0.1 ng / g-T in the total emission reference value indicated in the “New Guidelines”.
Because it is surely reduced to a level significantly below the EQ,
Special structure for oxygen deficiency (reducing atmosphere)
No device is required, and the device is inexpensive. Further, the cost of an inert gas or the like is not required.
【図1】本発明の第1の実施の形態に係る溶融飛灰又は
焼却飛灰の処理方法の説明図である。FIG. 1 is an explanatory diagram of a method for treating molten fly ash or incinerated fly ash according to a first embodiment of the present invention.
【図2】表1に示す組成の飛灰を300℃、400℃、
500℃、600℃、700℃の加熱温度でそれぞれ1
5分間加熱処理して得られる処理飛灰pH値と鉛溶出濃
度と加熱温度との関係をグラフにしたものである。FIG. 2 shows fly ash having the composition shown in Table 1 at 300 ° C., 400 ° C.,
500 ° C, 600 ° C, 700 ° C
5 is a graph showing the relationship between the treatment fly ash pH value, the lead elution concentration, and the heating temperature obtained by heating for 5 minutes.
【図3】表6に示す組成の飛灰を450℃、550℃、
650℃の加熱温度でそれぞれ30分間、空気中の酸化
雰囲気で加熱処理して得られた処理飛灰のダイオキシン
濃度と加熱温度との関係をグラフにしたものである。FIG. 3 shows fly ash having the composition shown in Table 6 at 450 ° C., 550 ° C.,
FIG. 4 is a graph showing the relationship between the dioxin concentration of the treated fly ash and the heating temperature obtained by performing the heat treatment in an oxidizing atmosphere in the air at a heating temperature of 650 ° C. for 30 minutes.
【図4】本発明の第2の実施の形態に係る飛灰の溶融飛
灰又は焼却飛灰の処理方法を適用する飛灰処理装置の説
明図である。FIG. 4 is an explanatory view of a fly ash processing apparatus to which a method for processing molten fly ash or incinerated fly ash according to a second embodiment of the present invention is applied.
10 飛灰処理装置 11 飛灰 13 窒素ガス 14 処理飛灰 15 高温処理炉 20 飛灰処理
装置 21 飛灰 22 混合機 23 水洗飛灰 24 処理水 25 水処理設備 26 濾過装置 28 処理飛灰 29 高温処理
炉DESCRIPTION OF SYMBOLS 10 Fly ash processing apparatus 11 Fly ash 13 Nitrogen gas 14 Processing fly ash 15 High temperature processing furnace 20 Fly ash processing apparatus 21 Fly ash 22 Mixer 23 Washing fly ash 24 Treated water 25 Water treatment equipment 26 Filtration device 28 Treated fly ash 29 High temperature Processing furnace
フロントページの続き (72)発明者 小佐野 秀実 福岡県北九州市戸畑区大字中原46−59 新 日本製鐵株式会社エンジニアリング事業本 部内 (72)発明者 長田 守弘 福岡県北九州市戸畑区大字中原46−59 新 日本製鐵株式会社エンジニアリング事業本 部内 (72)発明者 有光 功 福岡県北九州市戸畑区大字中原46−59 新 日本製鐵株式会社エンジニアリング事業本 部内Continued on the front page (72) Inventor Hidemi Kosano 46-59, Ohara Nakahara, Tobata-ku, Kitakyushu-shi, Fukuoka New (72) Inventor Morihiro Nagata 46-59, Nakahara Oaza, Tobata-ku, Kitakyushu-shi, Fukuoka Nippon Steel Corporation Engineering Business Unit (72) Inventor Isao Arimitsu 46-59 Ohara Nakahara, Tobata-ku, Kitakyushu-shi, Fukuoka New Nippon Steel Corporation Engineering Business Unit
Claims (4)
から発生する溶融飛灰、又は焼却炉から発生する焼却飛
灰の処理方法であって、 予め処理の対象とする前記溶融飛灰又は焼却飛灰のpH
を測定し、該測定値が11.0以上の場合、前記溶融飛
灰又は焼却飛灰を580〜800℃に加熱処理し、処理
飛灰のpHを8.5以上11.0未満にし、該処理飛灰
中の重金属の溶出を防止すると共に、該処理飛灰中に含
まれるダイオキシンも同時に分解することを特徴とする
溶融飛灰又は焼却飛灰の処理方法。1. A method for treating fly ash generated from a melting furnace for municipal garbage and / or industrial waste, or fly ash generated from an incinerator, comprising: PH of incinerated fly ash
When the measured value is 11.0 or more, the molten fly ash or incinerated fly ash is heated to 580 to 800 ° C., and the pH of the treated fly ash is set to 8.5 or more and less than 11.0. A method for treating molten fly ash or incinerated fly ash, comprising preventing elution of heavy metals in the treated fly ash and simultaneously decomposing dioxin contained in the treated fly ash.
から発生する溶融飛灰、又は焼却炉から発生する焼却飛
灰の処理方法であって、 予め処理の対象とする前記溶融飛灰又は焼却飛灰のpH
を測定し、該測定値が8.5未満の中性又は酸性の場
合、予めアルカリ源を加え、前記溶融飛灰又は焼却飛灰
のpHを一旦11.0以上にした後、次に前記溶融飛灰
又は焼却飛灰を580〜800℃に加熱処理し、処理飛
灰のpHを8.5以上11.0未満にし、該処理飛灰中
の重金属の溶出を防止すると共に、該処理飛灰中に含ま
れるダイオキシンも同時に分解することを特徴とする溶
融飛灰又は焼却飛灰の処理方法。2. A method for treating fly ash generated from a melting furnace for municipal garbage and / or industrial waste, or fly ash generated from an incinerator, comprising: PH of incinerated fly ash
If the measured value is less than 8.5 neutral or acidic, an alkali source is added in advance to adjust the pH of the molten fly ash or incinerated fly ash to 11.0 or higher, and then the The fly ash or incinerated fly ash is heat-treated at 580 to 800 ° C. to adjust the pH of the treated fly ash to 8.5 or more and less than 11.0 to prevent elution of heavy metals in the treated fly ash, A method for treating molten fly ash or incinerated fly ash, wherein dioxin contained therein is simultaneously decomposed.
から発生する溶融飛灰又は焼却炉から発生する焼却飛灰
の処理方法であって、 予め処理の対象とする前記溶融飛灰又は焼却飛灰を水洗
の後、水洗飛灰のpHを測定し、該測定値が12.0以
上の場合、前記水洗飛灰を580〜800℃に加熱処理
し、処理飛灰のpHを8.5以上11.8未満にし、該
処理飛灰中の重金属の溶出を防止すると共に、該処理飛
灰中に含まれるダイオキシンも同時に分解することを特
徴とする溶融飛灰又は焼却飛灰の処理方法。3. A method for treating molten fly ash generated from a melting furnace for municipal garbage and / or industrial waste or incinerated fly ash generated from an incinerator, wherein the molten fly ash or the incinerated material to be treated in advance is provided. After the fly ash is washed with water, the pH of the washed fly ash is measured. If the measured value is 12.0 or more, the washed fly ash is heated to 580 to 800 ° C. to adjust the pH of the treated fly ash to 8.5. A method for treating molten fly ash or incinerated fly ash, wherein the content is less than 11.8 to prevent elution of heavy metals in the treated fly ash and to simultaneously decompose dioxin contained in the treated fly ash.
から発生する溶融飛灰又は焼却炉から発生する焼却飛灰
の処理方法であって、 予め処理の対象とする前記溶融飛灰又は焼却飛灰を水洗
の後、水洗飛灰のpHを測定し、該測定値が8.5未満
の中性又は酸性の場合、予めアルカリ源を加え、前記水
洗飛灰のpHを一旦12.0以上にした後、次に前記水
洗飛灰を580〜800℃に加熱処理し、処理飛灰のp
Hを8.5以上11.8未満にし、該処理飛灰中の重金
属の溶出を防止すると共に、該処理飛灰中に含まれるダ
イオキシンも同時に分解することを特徴とする溶融飛灰
又は焼却飛灰の処理方法。4. A method for treating fly ash generated from a melting furnace for municipal garbage and / or industrial waste or fly ash generated from an incinerator, wherein said fly ash or incineration to be treated in advance is provided. After the fly ash is washed with water, the pH of the washed fly ash is measured. If the measured value is less than 8.5, which is neutral or acidic, an alkali source is added in advance to adjust the pH of the washed fly ash to 12.0 or more. After that, the washed fly ash is heated to 580 to 800 ° C.
H is set to 8.5 or more and less than 11.8 to prevent the elution of heavy metals in the treated fly ash and to simultaneously decompose dioxin contained in the treated fly ash. Ash treatment method.
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JP9-316498 | 1997-10-30 | ||
JP31649897 | 1997-10-30 | ||
JP30573398A JP3455118B2 (en) | 1997-10-30 | 1998-10-27 | Treatment method of molten fly ash or incinerated fly ash |
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CN115283424A (en) * | 2022-04-13 | 2022-11-04 | 江山市虎鼎环保科技有限公司 | Method for co-processing medical waste incineration fly ash and household garbage incineration fly ash |
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