JPH0919671A - Treatment of flying ashes - Google Patents

Treatment of flying ashes

Info

Publication number
JPH0919671A
JPH0919671A JP7169119A JP16911995A JPH0919671A JP H0919671 A JPH0919671 A JP H0919671A JP 7169119 A JP7169119 A JP 7169119A JP 16911995 A JP16911995 A JP 16911995A JP H0919671 A JPH0919671 A JP H0919671A
Authority
JP
Japan
Prior art keywords
fly ash
heavy metal
heavy metals
supercritical water
salts
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.)
Pending
Application number
JP7169119A
Other languages
Japanese (ja)
Inventor
Tetsuo Kimura
哲雄 木村
Yutaka Niekawa
豊 贄川
Tetsuo Kiyota
哲夫 清田
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.)
Kubota Corp
Original Assignee
Kubota Corp
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 Kubota Corp filed Critical Kubota Corp
Priority to JP7169119A priority Critical patent/JPH0919671A/en
Publication of JPH0919671A publication Critical patent/JPH0919671A/en
Pending legal-status Critical Current

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  • Fire-Extinguishing Compositions (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

PROBLEM TO BE SOLVED: To make it possible to completely separate and recover heavy metals and salts at the time of treating flying ashes contg. heavy metals and salts, such as NaCl and KCl, generated in an incineration treatment and melting treatment of waste. SOLUTION: A small amt. of acid 3 is added to flying ashes 1 to dissolve the heavy metals. The dissolved heavy metals are converted to complexes by addition of a heavy metal complexing agent 4. The flying ashes 5 contg. the complexes are supercritically extracted for suitable time by supercritical water 7, by which the flying ashes are separated to complex-contg. supercritical water 8 and extraction residues 11 contg. the salts. The complex-contg. supercritical water 8 is reduced in pressure and the heavy metal complex solids 10 precipitated by this pressure reduction are separate.

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
棄物などの廃棄物の焼却処理や溶融処理において発生し
た飛灰の処理方法に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating fly ash generated during incineration or melting of waste such as municipal solid waste and industrial waste.

【0002】[0002]

【従来の技術】従来、都市ごみや産業廃棄物などの廃棄
物は焼却炉において焼却され、ここで発生した焼却灰は
灰溶融炉において溶融されている。溶融によって生成さ
れる溶融スラグは、酸やアルカリに強くかつ重金属類が
溶出しにくいので、非常に安全・安定であるとともに、
その容積が焼却灰の1/2〜1/3に減縮されるという
利点を有している。
2. Description of the Related Art Conventionally, waste such as municipal waste and industrial waste is incinerated in an incinerator, and the incinerated ash generated here is melted in an ash melting furnace. The molten slag generated by melting is strong against acids and alkalis and difficult to elute heavy metals, so it is very safe and stable.
It has the advantage that the volume is reduced to 1/2 to 1/3 of the incineration ash.

【0003】しかるに、廃棄物の焼却処理や溶融処理の
際には飛灰が発生し、この飛灰中に高濃度の塩化カリウ
ムや塩化ナトリウムなどの塩類と少量の重金属類とが含
まれているので、飛灰中の重金属類を分離して飛灰を無
害化するとともに、塩類および重金属類を分離回収して
有効利用しようとする提案がなされている。たとえば、
NaHSなどを含んだ水で飛灰を洗浄して、重金属類を
含むスラッジと塩類が溶解した塩水とを分離回収する方
法が提案されている。
However, fly ash is generated during the incineration or melting of waste, and the fly ash contains a high concentration of salts such as potassium chloride and sodium chloride and a small amount of heavy metals. Therefore, it has been proposed to separate the heavy metals in the fly ash to render the fly ash harmless and to separate and collect the salts and heavy metals for effective use. For example,
A method has been proposed in which fly ash is washed with water containing NaHS or the like to separate and collect sludge containing heavy metals and salt water in which salts are dissolved.

【0004】[0004]

【発明が解決しようとする課題】しかしながら、上記し
た従来の分離回収方法では、飛灰の洗浄に多量の水を使
用するので、洗浄後の塩水の処理が困難であるという問
題がある。
However, in the above-mentioned conventional separation and recovery method, since a large amount of water is used for cleaning fly ash, there is a problem that it is difficult to treat salt water after cleaning.

【0005】また、重金属類のスラッジに塩水が付着す
るので、回収した重金属類に塩類が混入することは避け
られず、その品位が大幅に低下するという問題がある。
本発明は上記問題を解決するもので、重金属類と塩化カ
リウムや塩化ナトリウムなどの塩類とを完全に分離でき
るとともに、飛灰の洗浄に用いた水などを容易に処理で
きる飛灰の処理方法を提供することを目的とするもので
ある。
Further, since salt water adheres to the sludge of heavy metals, it is unavoidable that the recovered heavy metals are contaminated with salt, and there is a problem that the quality thereof is significantly lowered.
The present invention solves the above problems and provides a method for treating fly ash that can completely separate heavy metals and salts such as potassium chloride and sodium chloride, and can easily treat water and the like used for washing fly ash. It is intended to be provided.

【0006】[0006]

【課題を解決するための手段】上記問題を解決するため
に、本発明の飛灰の処理方法は、廃棄物の焼却処理や溶
融処理において発生した重金属類と塩化ナトリウムや塩
化カリウムなどの塩類とを含んだ飛灰の処理方法であっ
て、前記飛灰に少量の酸を加えて飛灰中の重金属類を溶
解させた後、重金属錯化剤を加えて重金属類錯体を生成
させ、この重金属類錯体を含んだ飛灰を超臨界水により
適当時間超臨界抽出して、重金属類錯体を超臨界水中に
抽出するとともに前記塩類を残留させ、前記重金属類錯
体を抽出した超臨界水は減圧してその溶解力を低下さ
せ、これにより重金属類錯体を析出させて分離するよう
にしたものである。
In order to solve the above problems, a method for treating fly ash according to the present invention is a method of treating heavy metals generated during incineration or melting of waste with salts such as sodium chloride and potassium chloride. A method of treating fly ash containing, wherein a small amount of acid is added to the fly ash to dissolve heavy metals in the fly ash, and then a heavy metal complexing agent is added to form a heavy metal complex, Supercritical water is extracted from the fly ash containing the complex with a supercritical water for a suitable time, the heavy metal complex is extracted into the supercritical water and the salts are left, and the supercritical water from which the heavy metal complex is extracted is decompressed. The solubility of the heavy metal complex is reduced, and thereby the heavy metal complex is deposited and separated.

【0007】一般に、飛灰中に含まれる重金属類は、酸
化物や塩化物などの種々の形態で存在している。上記構
成によれば、このような重金属類を錯体に変換して超臨
界水に抽出され易い形態としたので、超臨界抽出によっ
て、超臨界水中に抽出される重金属類錯体と、抽出され
ない塩化ナトリウムや塩化カリウムなどの塩類とに分離
できる。また超臨界水を減圧するとその溶解力が低下す
るので、重金属類錯体を抽出した超臨界水から重金属類
錯体を析出させることができる。よって、重金属類と塩
類の両者を乾固物として得ることができる。
Generally, heavy metals contained in fly ash exist in various forms such as oxides and chlorides. According to the above-mentioned configuration, since such heavy metals are converted into a complex and made into a form that is easily extracted into supercritical water, by the supercritical extraction, the heavy metal complexes extracted into supercritical water and unextracted sodium chloride are extracted. It can be separated into salts such as and potassium chloride. Further, when the pressure of the supercritical water is reduced, its dissolving power decreases, so that the heavy metal complex can be precipitated from the supercritical water from which the heavy metal complex has been extracted. Therefore, both the heavy metal and the salt can be obtained as a dried product.

【0008】また本発明の飛灰の処理方法は、重金属類
錯体を分離した後の超臨界状態あるいは一部ガス状態に
ある水を加熱圧縮して再び超臨界水となし、循環使用す
るようにしたものである。
In the method for treating fly ash according to the present invention, the water in the supercritical state or in the partial gas state after separating the heavy metal complex is heated and compressed to be made into supercritical water again, and is reused. It was done.

【0009】上記構成によれば、系外への水の排出がな
くなり、系外での水処理が不要となる。
According to the above construction, the water is not discharged to the outside of the system, and the water treatment outside the system becomes unnecessary.

【0010】[0010]

【発明の実施の形態】以下、本発明の飛灰の処理方法の
実施の形態を、図1に示したフローチャートを参照しな
がら説明する。
BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method for treating fly ash according to the present invention will be described below with reference to the flow chart shown in FIG.

【0011】図1において、被処理物質たる飛灰1は、
都市ごみや産業廃棄物などの廃棄物の焼却処理や溶融処
理において発生したものであり、塩化ナトリウムや塩化
カリウムの水溶性無機塩類を高濃度で含むとともに、水
銀などの重金属類を少量含んでいる。
In FIG. 1, the fly ash 1 as the substance to be treated is
It is generated in the incineration and melting processes of waste such as municipal waste and industrial waste. It contains a high concentration of water-soluble inorganic salts of sodium chloride and potassium chloride, and a small amount of heavy metals such as mercury. .

【0012】このような飛灰1を処理する際には、重金
属処理槽2の内部に飛灰1を投入して、この飛灰1に塩
酸などの酸3を少量加え、両者を攪拌混合して飛灰1中
の重金属類を溶解させる。次いで、槽2内の飛灰1に重
金属錯化剤4を加え、これらを攪拌混合して酸3に溶解
した重金属類を錯体に変換する。
When treating such fly ash 1, the fly ash 1 is put into a heavy metal treatment tank 2, a small amount of an acid 3 such as hydrochloric acid is added to the fly ash 1, and both are mixed by stirring. To dissolve heavy metals in fly ash 1. Next, the heavy metal complexing agent 4 is added to the fly ash 1 in the tank 2, and these are mixed by stirring to convert the heavy metals dissolved in the acid 3 into a complex.

【0013】次いで、槽2内の重金属類錯体を含んだ錯
体含有飛灰5を超臨界抽出槽6に導入し、圧力218a
tm以上、温度374℃以上の超臨界水7により適当時
間超臨界抽出して、飛灰5中の重金属類錯体を超臨界水
7中に抽出する。
Then, the complex-containing fly ash 5 containing the heavy metal complex in the tank 2 is introduced into the supercritical extraction tank 6, and the pressure 218a is applied.
Supercritical water 7 having a temperature of tm or higher and a temperature of 374 ° C. or higher is subjected to supercritical extraction for a proper time to extract the heavy metal complex in fly ash 5 into supercritical water 7.

【0014】その後、槽6内の重金属類錯体を含んだ錯
体含有超臨界水8を減圧槽9に導いて減圧する。この減
圧操作は錯体含有超臨界水8を超臨界状態に維持する範
囲内で行ってもよいし、減圧によって錯体含有超臨界水
8を臨界状態から気相に転移させてもよい。この減圧に
よって流体8の溶解力が低下し、重金属類錯体10が固
形物として析出するので、析出した重金属類錯体10を
減圧槽9より回収する。
Then, the complex-containing supercritical water 8 containing the heavy metal complex in the tank 6 is introduced into the decompression tank 9 to be decompressed. This depressurization operation may be performed within a range in which the complex-containing supercritical water 8 is maintained in the supercritical state, or the complex-containing supercritical water 8 may be transferred from the critical state to the gas phase by depressurizing. The reduced pressure reduces the dissolving power of the fluid 8 and the heavy metal complex 10 is deposited as a solid, and thus the deposited heavy metal complex 10 is recovered from the reduced pressure tank 9.

【0015】超臨界抽出槽5内に残留した塩類11を含
む抽出残渣を別途回収する。減圧槽9内の超臨界状態あ
るいは一部ガス状態の水12を減圧槽9より取り出し、
必要に応じて補給水13を加えたうえで、熱交換器14
において加熱し、圧縮機15において圧縮することによ
り超臨界水7に変換し、この超臨界水7を、超臨界抽出
槽6に循環返送して再利用する。
The extraction residue containing the salts 11 remaining in the supercritical extraction tank 5 is separately collected. The water 12 in the supercritical state or in the partial gas state in the decompression tank 9 is taken out from the decompression tank 9,
Make-up water 13 is added if necessary, and then heat exchanger 14
Is heated and compressed in the compressor 15 to be converted into supercritical water 7, and the supercritical water 7 is circulated back to the supercritical extraction tank 6 for reuse.

【0016】上記したように、超臨界水を循環使用する
ようにしたので、系外への水の排出はなく、従来の塩水
処理の問題を回避できる。また、超臨界水による抽出時
間を制御することで、重金属類とNaClやKClなど
の塩類との完全な分離を行える。さらに、抽出により分
離される重金属類と塩類は乾固物として得られるので、
取り扱いが容易である。
As described above, since the supercritical water is circulated and used, the water is not discharged to the outside of the system and the problem of the conventional salt water treatment can be avoided. In addition, by controlling the extraction time with supercritical water, it is possible to completely separate heavy metals from salts such as NaCl and KCl. Furthermore, since the heavy metals and salts separated by extraction are obtained as a dry matter,
Easy to handle.

【0017】[0017]

【発明の効果】以上のように本発明によれば、飛灰中の
重金属類は錯体に変換して超臨界水中に抽出し、飛灰中
のNaClやKClなどの塩類は抽出残渣として残留さ
せるようにしたので、重金属類と塩類を完全に分離で
き、かつ、それぞれを乾固物として得ることができる。
As described above, according to the present invention, heavy metals in fly ash are converted into complexes and extracted into supercritical water, and salts such as NaCl and KCl in fly ash are left as extraction residues. By doing so, heavy metals and salts can be completely separated, and each can be obtained as a dry solid.

【0018】また、重金属類と塩類を分離した後の水を
再び超臨界水となして循環使用するようにしたので、系
外への水の排出はなく、従来は必要であった多量の塩水
の処理が不要になる。
Further, since the water after separating the heavy metals and the salts is made into the supercritical water and circulated for reuse, the water is not discharged to the outside of the system, and a large amount of the salt water which has been conventionally required. Processing is unnecessary.

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

【図1】本発明の飛灰の処理方法の実施の形態を説明す
るフローチャートである。
FIG. 1 is a flowchart illustrating an embodiment of a fly ash processing method according to the present invention.

【符号の説明】[Explanation of symbols]

1 飛灰 3 酸 4 重金属錯化剤 5 錯体含有飛灰 7 超臨界水 8 錯体含有超臨界水 10 重金属類錯体(固形物) 11 塩類(抽出残渣) 12 超臨界状態あるいは一部ガス状態の水 1 Fly ash 3 Acid 4 Heavy metal complexing agent 5 Complex containing fly ash 7 Supercritical water 8 Complex containing supercritical water 10 Heavy metal complex (solid) 11 Salts (extraction residue) 12 Water in supercritical or partial gas state

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】 廃棄物の焼却処理や溶融処理において発
生した重金属類と塩化ナトリウムや塩化カリウムなどの
塩類とを含んだ飛灰の処理方法であって、前記飛灰に少
量の酸を加えて飛灰中の重金属類を溶解させた後、重金
属錯化剤を加えて重金属類錯体を生成させ、この重金属
類錯体を含んだ飛灰を超臨界水により適当時間超臨界抽
出して、重金属類錯体を超臨界水中に抽出するとともに
前記塩類を残留させ、前記重金属類錯体を抽出した超臨
界水は減圧してその溶解力を低下させ、これにより重金
属類錯体を析出させて分離することを特徴とする飛灰の
処理方法。
1. A method of treating fly ash containing heavy metals and salts such as sodium chloride and potassium chloride generated in the incineration and melting treatment of waste, which comprises adding a small amount of acid to the fly ash. After the heavy metals in the fly ash are dissolved, a heavy metal complexing agent is added to form a heavy metal complex, and the fly ash containing this heavy metal complex is supercritically extracted with supercritical water for an appropriate period of time to remove the heavy metals. The complex is extracted into supercritical water and the salts are left, and the supercritical water from which the heavy metal complex is extracted is decompressed to reduce its dissolving power, thereby precipitating and separating the heavy metal complex. Fly ash processing method.
【請求項2】 重金属類錯体を分離した後の超臨界状態
あるいは一部ガス状態にある水を加熱圧縮して再び超臨
界水となし、循環使用することを特徴とする請求項1記
載の飛灰の処理方法。
2. The fly according to claim 1, wherein water in a supercritical state or in a partial gas state after separating the heavy metal complex is heated and compressed to be made into supercritical water again, and is recycled. Ash treatment method.
JP7169119A 1995-07-05 1995-07-05 Treatment of flying ashes Pending JPH0919671A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7169119A JPH0919671A (en) 1995-07-05 1995-07-05 Treatment of flying ashes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7169119A JPH0919671A (en) 1995-07-05 1995-07-05 Treatment of flying ashes

Publications (1)

Publication Number Publication Date
JPH0919671A true JPH0919671A (en) 1997-01-21

Family

ID=15880652

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7169119A Pending JPH0919671A (en) 1995-07-05 1995-07-05 Treatment of flying ashes

Country Status (1)

Country Link
JP (1) JPH0919671A (en)

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