JP3387694B2 - Fly ash treatment method - Google Patents
Fly ash treatment methodInfo
- Publication number
- JP3387694B2 JP3387694B2 JP15209795A JP15209795A JP3387694B2 JP 3387694 B2 JP3387694 B2 JP 3387694B2 JP 15209795 A JP15209795 A JP 15209795A JP 15209795 A JP15209795 A JP 15209795A JP 3387694 B2 JP3387694 B2 JP 3387694B2
- Authority
- JP
- Japan
- Prior art keywords
- fly ash
- heavy metal
- carbon dioxide
- complex
- fluid
- 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.)
- Expired - Fee Related
Links
- 239000010881 fly ash Substances 0.000 title claims description 35
- 238000000034 method Methods 0.000 title claims description 9
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 48
- 229910001385 heavy metal Inorganic materials 0.000 claims description 44
- 239000012530 fluid Substances 0.000 claims description 27
- 239000001569 carbon dioxide Substances 0.000 claims description 24
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 24
- 150000004696 coordination complex Chemical class 0.000 claims description 13
- 238000002844 melting Methods 0.000 claims description 7
- 230000008018 melting Effects 0.000 claims description 7
- 238000000194 supercritical-fluid extraction Methods 0.000 claims description 7
- 239000002699 waste material Substances 0.000 claims description 7
- 239000002253 acid Substances 0.000 claims description 5
- 239000007787 solid Substances 0.000 claims description 5
- 239000008139 complexing agent Substances 0.000 claims description 4
- 238000000605 extraction Methods 0.000 claims description 2
- 150000003839 salts Chemical class 0.000 description 10
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 230000006837 decompression Effects 0.000 description 4
- 239000002956 ash Substances 0.000 description 3
- 239000002440 industrial waste Substances 0.000 description 3
- 239000010802 sludge Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000010813 municipal solid waste Substances 0.000 description 2
- 239000001103 potassium chloride Substances 0.000 description 2
- 235000011164 potassium chloride Nutrition 0.000 description 2
- 238000003672 processing method Methods 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- HYHCSLBZRBJJCH-UHFFFAOYSA-M sodium hydrosulfide Chemical compound [Na+].[SH-] HYHCSLBZRBJJCH-UHFFFAOYSA-M 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/20—Waste processing or separation
Landscapes
- Processing Of Solid Wastes (AREA)
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】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重
金属類や水溶性塩類を含む飛灰の処理方法に関する。
【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処理され、ここで発生した焼却
灰は灰溶融炉において溶融処理されている。溶融処理に
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。
【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水溶性塩類と少量の重金属類
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、水溶性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、飛灰をＮａＨＳなどを含んだ水で洗浄して、
重金属類を含むスラッジと水溶性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。
【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、重金属類スラッジに塩水が
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。
【０００５】本発明は上記問題を解決するもので、重金
属類を効率よく分離回収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。
【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に含まれる重金属類を溶
解させ、この飛灰に重金属錯化剤を加えて前記溶解した
重金属類を錯体に変換し、この重金属類錯体を含んだ飛
灰を二酸化炭素超臨界流体により超臨界抽出して重金属
類錯体を二酸化炭素超臨界流体中に抽出し、得られた重
金属類錯体を含んだ二酸化炭素超臨界流体を減圧してこ
の流体の溶解力を低減させ、重金属類錯体を固体として
回収するようにしたものである。
【０００７】
【作用】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が錯体に変換されて抽出さ
れ易い形態とされるので、二酸化炭素超臨界流体により
飛灰の超臨界抽出を行うと、重金属類錯体は二酸化炭素
超臨界流体中に抽出され、その他の塩類は残留する。こ
の重金属類錯体を含んだ二酸化炭素超臨界流体を減圧す
ると、流体の溶解力が低下して重金属類錯体が固体とし
て分離されるので、重金属類のみを回収できる。
【０００８】
【実施例】以下、本発明の一実施例の飛灰の処理方法
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。
【０００９】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。
【００１０】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重金属類を
錯体に変換する。
【００１１】そして、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、二酸化炭素超
臨界流体７により適当時間超臨界抽出して、飛灰５中の
重金属類錯体を二酸化炭素超臨界流体７中に抽出する。
【００１２】その後、槽６内の重金属類錯体を含んだ錯
体含有二酸化炭素超臨界流体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二酸化炭素超臨界流体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
によって錯体含有二酸化炭素超臨界流体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、流体８は二酸化炭素流体１０と重金属
類錯体を含んだ固体１１とに分離するので、固体１１を
減圧槽９より回収する。
【００１３】超臨界抽出槽５内に残留した塩類を含む抽
出残渣１２を別途回収する。減圧槽９内の二酸化炭素流
体１０は、槽９外に取り出し、必要に応じて補給二酸化
炭素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二酸化炭素
超臨界流体に変換する。得られた二酸化炭素超臨界流体
７は、超臨界抽出槽６に循環返送して再利用する。
【００１４】上記したように、重金属類を錯体に変換し
たことにより、二酸化炭素超臨界流体を用いて重金属類
を超臨界抽出でき、重金属類を効率よく分離回収でき
る。
【００１５】
【発明の効果】以上のように本発明によれば、飛灰中の
重金属類を錯体に変換することによって、低温・低圧で
超臨界状態となる二酸化炭素を用いて重金属類のみを超
臨界抽出し、乾固物として得ることができるので、コス
トおよび安全性等の点で有利である。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fly ash containing heavy metals and water-soluble salts generated during incineration and melting of waste such as municipal solid waste and industrial waste. Regarding the processing method. [0002] 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 produced by the melting treatment is very safe and stable because it is resistant to acids and alkalis and hard to elute heavy metals, and its volume is reduced to 1/2 to 1/3 of the incinerated ash. Has advantages. [0003] However, fly ash is generated during the incineration or melting of waste, and this fly ash contains high concentrations of water-soluble salts such as potassium chloride and sodium chloride and a small amount of heavy metals. Therefore, proposals have been made to separate heavy metals in fly ash to make the fly ash harmless, and to separate and collect water-soluble salts and heavy metals for effective use.
For example, fly ash is washed with water containing NaHS, etc.
A method of separating and recovering sludge containing heavy metals and salt water in which water-soluble salts are dissolved has been proposed. However, in the conventional separation and recovery method described above, since salt water adheres to the sludge of heavy metals, it is inevitable that salts are mixed in the recovered heavy metals, and the quality of the sludge is inevitable. Is greatly reduced. An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a method for treating fly ash capable of efficiently separating and recovering heavy metals. [0006] In order to solve the above problems, a method for treating fly ash according to the present invention is a method for treating fly ash generated in incineration or melting of waste, A small amount of acid is added to the fly ash to dissolve heavy metals contained in the fly ash, and a heavy metal complexing agent is added to the fly ash to convert the dissolved heavy metals into a complex, including the heavy metal complex. Supercritical extraction of fly ash with carbon dioxide supercritical fluid to extract heavy metal complex into carbon dioxide supercritical fluid, and decompression of carbon dioxide supercritical fluid containing heavy metal complex It is designed to reduce the dissolving power and recover heavy metal complexes as solids. [0007] Generally, heavy metals contained in fly ash exist in various forms such as oxides and chlorides. According to the above configuration, since such heavy metals are converted into a complex to be easily extracted, when supercritical extraction of fly ash is performed with a carbon dioxide supercritical fluid, the heavy metal complex becomes carbon dioxide supercritical. Extracted into the fluid, other salts remain. When the pressure of the carbon dioxide supercritical fluid containing the heavy metal complex is reduced, the dissolving power of the fluid is reduced and the heavy metal complex is separated as a solid, so that only the heavy metal can be recovered. A method for treating fly ash according to one embodiment of the present invention will be described below with reference to the flowchart shown in FIG. In FIG. 1, fly ash 1 as a substance to be treated is
It is generated during the incineration and melting treatment of waste such as municipal solid waste and industrial waste, and contains a high concentration of water-soluble salts of sodium chloride and potassium chloride and a small amount of heavy metals such as mercury. When treating such fly ash 1, the fly ash 1 is charged into the heavy metal treatment tank 2, a small amount of an acid 3 such as hydrochloric acid is added to the fly ash 1, and the two are stirred and mixed. To dissolve the heavy metals in the fly ash 1. Next, the heavy metal complexing agent 4 is added to the fly ash 1 in the tank 2, and these are stirred and mixed to convert heavy metals into a complex. Then, the fly ash 5 containing the complex containing the heavy metal complex in the tank 2 is introduced into the supercritical extraction tank 6 and supercritically extracted with a carbon dioxide supercritical fluid 7 for an appropriate time. The heavy metal complex is extracted into the carbon dioxide supercritical fluid 7. Thereafter, the complex-containing carbon dioxide supercritical fluid 8 containing the heavy metal complex in the tank 6 is led to a decompression tank 9 where the pressure is reduced. This decompression operation is performed using the complex-containing carbon dioxide supercritical fluid 8.
May be performed within a range in which the supercritical fluid is maintained in a supercritical state, or the complex-containing carbon dioxide supercritical fluid 8 may be transitioned from a critical state to a gas phase by reducing the pressure. Due to this reduced pressure, the dissolving power of the fluid 8 is reduced, and the fluid 8 is separated into the carbon dioxide fluid 10 and the solid 11 containing the heavy metal complex. An extraction residue 12 containing salts remaining in the supercritical extraction tank 5 is separately collected. The carbon dioxide fluid 10 in the decompression tank 9 is taken out of the tank 9, added with supplementary carbon dioxide 13 as needed, heated in a heat exchanger 14, and compressed in a compressor 15 to reduce the carbon dioxide flow. Convert to critical fluid. The obtained supercritical carbon dioxide fluid 7 is circulated and returned to the supercritical extraction tank 6 for reuse. As described above, by converting heavy metals into complexes, heavy metals can be supercritically extracted using a carbon dioxide supercritical fluid, and heavy metals can be efficiently separated and recovered. As described above, according to the present invention, by converting heavy metals in fly ash into a complex, only heavy metals can be converted to a supercritical state at low temperature and low pressure using carbon dioxide. It can be obtained as a dried product by supercritical extraction, which is advantageous in terms of cost and safety.
【図面の簡単な説明】
【図１】本発明の一実施例の飛灰の処理方法を説明する
フローチャートである。
【符号の説明】
１ 飛灰
３ 酸
４ 重金属錯化剤
５ 錯体含有飛灰
７ 二酸化炭素超臨界流体
８ 錯体含有二酸化炭素超臨界流体
10 二酸化炭素流体
11 固体BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flowchart illustrating a fly ash processing method according to an embodiment of the present invention. [Description of Signs] 1 Fly ash 3 Acid 4 Heavy metal complexing agent 5 Complex containing fly ash 7 Carbon dioxide supercritical fluid 8 Complex containing carbon dioxide supercritical fluid 10 Carbon dioxide fluid 11 Solid
───────────────────────────────────────────────────── フロントページの続き (72)発明者 芝軒 悟 大阪府大阪市浪速区敷津東一丁目２番47 号 株式会社クボタ内 (56)参考文献 特開 平８−52315（ＪＰ，Ａ) 特開 平８−291345（ＪＰ，Ａ) 特開 平７−185593（ＪＰ，Ａ) 特開 昭61−101711（ＪＰ，Ａ) 特表2002−508697（ＪＰ，Ａ) 国際公開95／33542（ＷＯ，Ａ１) (58)調査した分野(Int.Cl.7，ＤＢ名) B09B 3/00 C02F 1/74 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Satoru Shibaken 1-47, Shishitsuhigashi, Namiwa-ku, Osaka-shi, Osaka Kubota Co., Ltd. JP-A-8-291345 (JP, A) JP-A-7-185593 (JP, A) JP-A-61-101711 (JP, A) JP-T-2002-508697 (JP, A) International publication 95/33542 (WO , A1) (58) Field surveyed (Int. Cl. 7 , DB name) B09B 3/00 C02F 1/74
Claims (1)
生した飛灰の処理方法であって、前記飛灰に少量の酸を
加えて飛灰中に含まれる重金属類を溶解させ、この飛灰
に重金属錯化剤を加えて前記溶解した重金属類を錯体に
変換し、この重金属類錯体を含んだ飛灰を二酸化炭素超
臨界流体により超臨界抽出して重金属類錯体を二酸化炭
素超臨界流体中に抽出し、得られた重金属類錯体を含ん
だ二酸化炭素超臨界流体を減圧してこの流体の溶解力を
低減させ、重金属類錯体を固体として回収することを特
徴とする飛灰の処理方法。(57) [Claim 1] A method for treating fly ash generated during incineration or melting of waste, wherein a small amount of acid is added to the fly ash and the fly ash is included in the fly ash. A heavy metal is dissolved, a heavy metal complexing agent is added to the fly ash to convert the dissolved heavy metal into a complex, and the fly ash containing the heavy metal complex is subjected to supercritical extraction with a carbon dioxide supercritical fluid to perform heavy metal extraction. Extracting the complex into a carbon dioxide supercritical fluid, decompressing the obtained carbon dioxide supercritical fluid containing the heavy metal complex, reducing the dissolving power of this fluid, and recovering the heavy metal complex as a solid. Characteristic fly ash treatment method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15209795A JP3387694B2 (en) | 1995-06-20 | 1995-06-20 | Fly ash treatment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15209795A JP3387694B2 (en) | 1995-06-20 | 1995-06-20 | Fly ash treatment method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH091104A JPH091104A (en) | 1997-01-07 |
| JP3387694B2 true JP3387694B2 (en) | 2003-03-17 |
Family
ID=15532991
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15209795A Expired - Fee Related JP3387694B2 (en) | 1995-06-20 | 1995-06-20 | Fly ash treatment method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3387694B2 (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61101711A (en) * | 1984-10-24 | 1986-05-20 | Hirochika Okuyama | Method for making incinerated ash harmless |
| US5730874A (en) * | 1991-06-12 | 1998-03-24 | Idaho Research Foundation, Inc. | Extraction of metals using supercritical fluid and chelate forming legand |
| JPH07185593A (en) * | 1993-12-27 | 1995-07-25 | Fuji Photo Film Co Ltd | Treatment of waste liquid containing metallic chelate complex |
| GB9413875D0 (en) * | 1994-07-09 | 1994-08-31 | British Nuclear Fuels Plc | Separating solutes from solutions |
| JP3348808B2 (en) * | 1995-04-20 | 2002-11-20 | 三菱マテリアル株式会社 | Separation and recovery of platinum group elements in solution |
-
1995
- 1995-06-20 JP JP15209795A patent/JP3387694B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH091104A (en) | 1997-01-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |