JP3569796B2 - Detoxification of incinerated ash or molten ash - Google Patents
Detoxification of incinerated ash or molten ash Download PDFInfo
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- JP3569796B2 JP3569796B2 JP22697598A JP22697598A JP3569796B2 JP 3569796 B2 JP3569796 B2 JP 3569796B2 JP 22697598 A JP22697598 A JP 22697598A JP 22697598 A JP22697598 A JP 22697598A JP 3569796 B2 JP3569796 B2 JP 3569796B2
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- ash
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Description
【０００１】
【発明の属する技術分野】
本発明は、焼却炉から出る焼却灰もしくは溶融炉から出る溶融灰中に含まれるダイオキシン等の有害な有機化合物を無害化する方法に関する。
【０００２】
【従来の技術】
焼却灰や溶融灰中のダイオキシン等の有害な有機化合物を無害化する方法の１つとして、加熱処理がある。これは焼却灰や溶融灰を３００℃以上に加熱することによって、灰中の有機化合物を熱分解させる方法である。
【０００３】
最近、廃棄物の多様化に伴って産業廃棄物焼却炉から排出される焼却灰には、一般廃棄物焼却炉から排出される焼却灰とは組成を異にするものがあることが判った。産業廃棄物焼却灰の分析例を表１に、一般廃棄物焼却灰の分析例を表２にそれぞれ示す。
【０００４】
【表１】
【表２】
ここで両者の間で大きく異なる点は、後者の焼却灰にはＳｉＯ２ やＡｌ２ Ｏ３ のような難分解性酸化物が５０重量％以上存在しているのに対し、前者の焼却灰にはこのような難分解性酸化物はほとんど存在せず、９０重量％以上が塩化物として存在している。また、前者の焼却灰には重金属類も多い。一般に重金属類の塩化物は低い融点を有する。さらに、複数の重金属類の塩化物が共存すると、この混合物の融点は単独のときの融点より低くなる。そのため、加熱処理による無害化処理を行う場合、一般廃棄物焼却灰は３００℃加熱で溶けることはないが、産業廃棄物焼却灰は３００℃加熱で溶ける可能性がある。焼却灰が３００℃加熱で溶けると、以下のような問題が生じる。
【０００７】
▲１▼塩化物の融液が金属腐食を引き起こす。
▲２▼無害化処理後の灰が冷却時に固まってしまい、装置閉塞を引き起こす。
▲３▼無害化処理効率が低い（３００℃加熱でもダイオキシンが分解しない例がある）。
【０００８】
また、このような産業廃棄物焼却灰と、一般・産業廃棄物溶融飛灰とは同様な組成を有する。一般・産業廃棄物溶融飛灰の組成を表３に示す。
【０００９】
【表３】
このため、一般・産業廃棄物溶融飛灰を加熱処理により無害化処理する場合にも、上記のような問題が生じる。
【００１１】
【発明が解決しようとする課題】
本発明は、焼却灰もしくは溶融灰の無害化を確実に行うことができる方法を提供することを目的とするものである。
【００１２】
【課題を解決するための手段】
本発明による焼却灰もしくは溶融灰の無害化方法は、ダイオキシン等の有害な有機化合物を含有する低融点の焼却灰または溶融灰を３００℃程度の加熱処理により無害化するに当たり、前処理として、高融点・難分解性酸化物であるＳｉＯ２ および／またはＡｌ２ Ｏ３ を主成分として含む鉱物を灰に混入することにより、灰の融点を上げることを特徴とする方法である。ＳｉＯ２ を主成分として含む鉱物の代表例としてはけいそう土が挙げられる。
【００１３】
本発明方法で用いる、ＳｉＯ２ および／またはＡｌ ２ Ｏ ３ を主成分として含む鉱物は、焼却灰または溶融灰中のＳｉＯ２ とＡｌ２ Ｏ３ の和が好ましくは１０重量％以上、より好ましくは１０〜３０重量％の範囲になるように混入する。
【００１４】
Ａｌ２ Ｏ３ を主成分として含む鉱物の代表例としてはアルミナが挙げられる。ＳｉＯ２ とＡｌ２ Ｏ３ を共に主成分として含む鉱物の代表例としては砂が挙げられる。砂の粒径は飛灰の粒径と同様の１０μｍ程度であることが好ましい。
【００１５】
【発明の実施の形態】
つぎに、本発明の実施例を挙げるが、本発明はこれに限定されるものではない。
【００１６】
焼却灰もしくは溶融灰を含む排ガスを、バグフィルターや電気集塵機等の集塵装置に通し、除塵後の排ガスを煙突から大気中へ放出した。集塵装置で集めた焼却灰もしくは溶融灰を無害化装置へ送る前に、飛灰に砂を混入した。砂は、ＳｉＯ２ とＡｌ２ Ｏ３ を共に主成分として含む鉱物である。砂の混入比は、焼却灰または溶融灰中のＳｉＯ２ とＡｌ２ Ｏ３ の和が１５重量％になるように決めた。
【００１７】
その後、砂を含む飛灰を無害化処理装置内で加熱処理して、ダイオキシン等の有機化合物を無害化した後、装置外へ排出した。
【００１８】
表４は、産業廃棄物焼却灰を３００℃で２０時間加熱処理した後の性状およびダイオキシン分解率をけいそう土混入率に対して示したものである。
【００１９】
【表４】
このように低融点灰中にＳｉＯ２ とＡｌ２ Ｏ３ のような高融点・難分解性酸化物を混入すると、灰自身の融点は高くなり、そのときのダイオキシン分解率も高くなった。すなわち従来の技術の項で示した▲１▼〜▲３▼の問題点がいずれも解決された。
【００２１】
また、一般・産業廃棄物溶融飛灰についても表４の結果と同様な傾向が得られた。
【００２２】
【発明の効果】
ＳｉＯ２ および／またはＡｌ２ Ｏ３ のような高融点・難分解性酸化物を低融点の焼却灰や溶融灰に混入することによって、
▲１▼灰自身の融点が上がる、
▲２▼灰の加熱無害化処理において、塩化物の融液が生じない、
▲３▼灰の加熱無害化処理において、灰が固化することがなくなり、安定して運転できる、および、
▲４▼灰の加熱無害化処理において、従来の一般廃棄物焼却灰の加熱無害化処理の場合と同様のダイオキシン分解率が得られる、
といった効果が発揮される。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for detoxifying harmful organic compounds such as dioxin contained in incineration ash from an incinerator or molten ash from a melting furnace.
[0002]
[Prior art]
Heat treatment is one method of detoxifying harmful organic compounds such as dioxin in incinerated ash and molten ash. This is a method in which organic compounds in ash are thermally decomposed by heating incinerated ash or molten ash to 300 ° C. or higher.
[0003]
Recently, it has been found that incineration ash discharged from industrial waste incinerators due to diversification of wastes has a different composition from incineration ash discharged from general waste incinerators. Table 1 shows an example of analysis of industrial waste incineration ash, and Table 2 shows an example of analysis of general waste incineration ash.
[0004]
[Table 1]
[Table 2]
Here, the major difference between the two is that the latter incineration ash contains 50% by weight or more of a hardly decomposable oxide such as SiO 2 or Al 2 O 3 , whereas the former incineration ash does not. Almost no such hardly decomposable oxide is present, and 90% by weight or more is present as chloride. The former incinerated ash contains many heavy metals. Generally, chlorides of heavy metals have a low melting point. Furthermore, when a plurality of heavy metal chlorides coexist, the melting point of this mixture becomes lower than the melting point when used alone. Therefore, when performing the detoxification treatment by the heat treatment, the incineration ash of general waste does not melt at 300 ° C. heating, but the incineration ash of industrial waste may melt at 300 ° C. heating. When the incinerated ash is melted by heating at 300 ° C., the following problems occur.
[0007]
{Circle around (1)} The chloride melt causes metal corrosion.
{Circle around (2)} The ash after the detoxification process solidifies during cooling, causing blockage of the device.
{Circle around (3)} Detoxification efficiency is low (dioxin does not decompose even when heated at 300 ° C.).
[0008]
Further, such industrial waste incinerated ash and general / industrial waste molten fly ash have the same composition. Table 3 shows the composition of general and industrial waste molten fly ash.
[0009]
[Table 3]
For this reason, the above-described problem also occurs when detoxifying the molten fly ash from general and industrial wastes by heat treatment.
[0011]
[Problems to be solved by the invention]
An object of the present invention is to provide a method capable of reliably detoxifying incinerated ash or molten ash.
[0012]
[Means for Solving the Problems]
The method for detoxifying incinerated ash or molten ash according to the present invention is a method for detoxifying low-melting incinerated ash or molten ash containing a harmful organic compound such as dioxin by a heat treatment at about 300 ° C. This is a method characterized by increasing the melting point of the ash by mixing a mineral containing SiO 2 and / or Al 2 O 3 , which is a melting point and hardly decomposable oxide, as a main component into the ash. Diatomaceous earth is a typical example of a mineral containing SiO 2 as a main component.
[0013]
In the mineral containing SiO 2 and / or Al 2 O 3 as a main component used in the method of the present invention, the sum of SiO 2 and Al 2 O 3 in incinerated ash or molten ash is preferably at least 10% by weight, more preferably It is mixed so as to be in the range of 10 to 30% by weight.
[0014]
A typical example of a mineral containing Al 2 O 3 as a main component is alumina. A typical example of a mineral containing both SiO 2 and Al 2 O 3 as main components is sand. The particle size of the sand is preferably about 10 μm, which is the same as the particle size of the fly ash.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, examples of the present invention will be described, but the present invention is not limited thereto.
[0016]
Exhaust gas containing incinerated ash or molten ash was passed through a dust collector such as a bag filter or an electric dust collector, and the exhaust gas after dust removal was discharged into the atmosphere from a chimney. Before incineration ash or molten ash collected by the dust collector was sent to the detoxification device, sand was mixed into the fly ash. Sand is a mineral containing both SiO 2 and Al 2 O 3 as main components. The mixing ratio of sand was determined such that the sum of SiO 2 and Al 2 O 3 in the incinerated ash or molten ash was 15% by weight.
[0017]
Thereafter, the fly ash containing sand was heat-treated in a detoxifying apparatus to detoxify organic compounds such as dioxin, and then discharged outside the apparatus.
[0018]
Table 4 shows the properties and the dioxin decomposition rate after the heat treatment of the industrial waste incinerated ash at 300 ° C. for 20 hours with respect to the diatomaceous earth mixing rate.
[0019]
[Table 4]
When a high melting point and hardly decomposable oxide such as SiO 2 and Al 2 O 3 are mixed in the low melting point ash, the melting point of the ash itself increases and the dioxin decomposition rate at that time also increases. That is, all of the problems (1) to (3) described in the section of the prior art were solved.
[0021]
The same tendency as in the results of Table 4 was obtained for the molten fly ash of general and industrial wastes.
[0022]
【The invention's effect】
By mixing a high melting point and hardly decomposable oxide such as SiO 2 and / or Al 2 O 3 into low melting point incineration ash or molten ash,
(1) The melting point of the ash itself rises.
(2) In the heat detoxification treatment of ash, no chloride melt is produced.
(3) In the ash heat detoxification treatment, the ash does not solidify and can be operated stably; and
(4) In the heat detoxification treatment of ash, the same dioxin decomposition rate as in the case of conventional heat detoxification treatment of incinerated ash can be obtained.
Such an effect is exhibited.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22697598A JP3569796B2 (en) | 1998-08-11 | 1998-08-11 | Detoxification of incinerated ash or molten ash |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22697598A JP3569796B2 (en) | 1998-08-11 | 1998-08-11 | Detoxification of incinerated ash or molten ash |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000051818A JP2000051818A (en) | 2000-02-22 |
| JP3569796B2 true JP3569796B2 (en) | 2004-09-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22697598A Expired - Fee Related JP3569796B2 (en) | 1998-08-11 | 1998-08-11 | Detoxification of incinerated ash or molten ash |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3569796B2 (en) |
-
1998
- 1998-08-11 JP JP22697598A patent/JP3569796B2/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| JP2000051818A (en) | 2000-02-22 |
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