JPH105736A - Treatment of alkaline fly ash - Google Patents
Treatment of alkaline fly ashInfo
- Publication number
- JPH105736A JPH105736A JP8177170A JP17717096A JPH105736A JP H105736 A JPH105736 A JP H105736A JP 8177170 A JP8177170 A JP 8177170A JP 17717096 A JP17717096 A JP 17717096A JP H105736 A JPH105736 A JP H105736A
- Authority
- JP
- Japan
- Prior art keywords
- fly ash
- alkaline
- slurry
- water
- added
- 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
Links
- 239000010881 fly ash Substances 0.000 title claims abstract description 82
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 42
- 239000002002 slurry Substances 0.000 claims abstract description 36
- 238000000034 method Methods 0.000 claims abstract description 30
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims abstract description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000007787 solid Substances 0.000 claims abstract description 23
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims abstract description 17
- 239000000920 calcium hydroxide Substances 0.000 claims abstract description 17
- 235000011116 calcium hydroxide Nutrition 0.000 claims abstract description 17
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims abstract description 17
- 229910052745 lead Inorganic materials 0.000 claims abstract description 17
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 17
- 229910052802 copper Inorganic materials 0.000 claims abstract description 15
- 230000005484 gravity Effects 0.000 claims abstract description 15
- 238000000926 separation method Methods 0.000 claims abstract description 14
- 239000007788 liquid Substances 0.000 claims abstract description 10
- 239000007791 liquid phase Substances 0.000 claims abstract description 9
- 150000003839 salts Chemical class 0.000 claims abstract description 7
- 238000002386 leaching Methods 0.000 claims description 13
- 239000003795 chemical substances by application Substances 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 7
- 239000007864 aqueous solution Substances 0.000 claims description 6
- 238000005406 washing Methods 0.000 claims description 5
- 239000004035 construction material Substances 0.000 claims description 3
- 239000000243 solution Substances 0.000 claims 1
- 150000003568 thioethers Chemical class 0.000 claims 1
- 239000010419 fine particle Substances 0.000 abstract 1
- 239000003513 alkali Substances 0.000 description 11
- 229910001385 heavy metal Inorganic materials 0.000 description 10
- 239000002253 acid Substances 0.000 description 8
- 238000004458 analytical method Methods 0.000 description 5
- 239000000706 filtrate Substances 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- HYHCSLBZRBJJCH-UHFFFAOYSA-M sodium hydrosulfide Chemical compound [Na+].[SH-] HYHCSLBZRBJJCH-UHFFFAOYSA-M 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 4
- 238000010828 elution Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 3
- 239000002956 ash Substances 0.000 description 3
- 238000010908 decantation Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000006386 neutralization reaction Methods 0.000 description 3
- 238000005987 sulfurization reaction Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- YLQBMQCUIZJEEH-UHFFFAOYSA-N Furan Chemical compound C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 239000002910 solid waste Substances 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000005486 sulfidation Methods 0.000 description 2
- 150000004763 sulfides Chemical class 0.000 description 2
- 239000002562 thickening agent Substances 0.000 description 2
- HGUFODBRKLSHSI-UHFFFAOYSA-N 2,3,7,8-tetrachloro-dibenzo-p-dioxin Chemical compound O1C2=CC(Cl)=C(Cl)C=C2OC2=C1C=C(Cl)C(Cl)=C2 HGUFODBRKLSHSI-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007922 dissolution test Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 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
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000006228 supernatant Substances 0.000 description 1
Landscapes
- Fire-Extinguishing Compositions (AREA)
- Processing Of Solid Wastes (AREA)
- Separation Of Solids By Using Liquids Or Pneumatic Power (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、飛灰の処理方法に
係り、特に、都市ゴミやシュレッダーダスト等の固形廃
棄物を焼却する際、及び焼却灰や焼却飛灰を溶融する際
に発生するアルカリ性飛灰を減容化及び／又は無害化と
資源化処理する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating fly ash, and more particularly to a method for incinerating solid waste such as municipal waste and shredder dust and melting the incinerated ash and incinerated fly ash. The present invention relates to a method for reducing the volume and / or detoxifying and recycling alkaline fly ash.
【０００２】[0002]
【従来の技術】固形廃棄物の焼却減容化処理又は焼却灰
や飛灰の溶融減容化処理において、飛灰と共に塩化水素
等の酸性ガスが発生する。該酸性ガスの処理には紛状の
消石灰を吹き込む、いわゆる乾式処理法が広く用いられ
ている。この場合、バッグフィルターにてアルカリ性飛
灰が回収される。アルカリ性飛灰は特別管理一般廃棄物
に指定されており、その埋め立て処分には無害化のため
の重金属安定化処理が必要である。しかし、アルカリ性
飛灰の重金属安定化処理はコストが高く、また、埋め立
て処分場の確保が益々困難となっている問題がある。そ
うした状況の中で、飛灰の減容化、無害化と資源化を目
的とする処理技術の開発が盛んに行われている。例え
ば、飛灰を酸浸出することにより重金属を回収する方法
がある。しかしながら、アルカリ性飛灰に消石灰や酸化
マグネシウム等、塩基性物質が多く含まれているため、
従来の酸浸出法を該飛灰に適用した場合に、大量の鉱酸
が必要で、処理コストが高く、また装置の腐食など問題
が多い。2. Description of the Related Art In the process of reducing the volume of solid waste by incineration or the process of melting and reducing the volume of incinerated ash and fly ash, acid gases such as hydrogen chloride are generated together with the fly ash. A so-called dry treatment method, in which powdered slaked lime is blown, is widely used for treating the acid gas. In this case, the alkaline fly ash is collected by the bag filter. Alkaline fly ash is designated as specially managed municipal waste, and its landfill requires stabilization of heavy metals to make it harmless. However, there is a problem in that the heavy metal stabilization treatment of alkaline fly ash is expensive, and it is increasingly difficult to secure a landfill disposal site. Under such circumstances, the development of processing technology for the purpose of reducing the volume, harmlessness and recycling of fly ash has been actively carried out. For example, there is a method of recovering heavy metals by acid leaching fly ash. However, since alkaline fly ash contains a lot of basic substances such as slaked lime and magnesium oxide,
When the conventional acid leaching method is applied to the fly ash, a large amount of mineral acid is required, the treatment cost is high, and there are many problems such as corrosion of the equipment.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、上記従来技
術の問題を解決し、経済的にアルカリ性飛灰を減容化及
び／又は無害化処理すると共に、資源化することができ
るアルカリ性飛灰の処理方法を提供することを課題とす
る。DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and provides an alkaline fly ash that can be economically reduced in volume and / or detoxified and recycled. It is an object of the present invention to provide a processing method.
【０００４】[0004]
【課題を解決するための手段】上記課題を解決するため
に、本発明では、アルカリ性飛灰を減容化及び無害化す
る処理方法において、該飛灰に水を添加して水スラリー
を調合し、調合した水スラリーを湿式比重選鉱すること
により、粒径が数μｍと細かくて、比重の軽い消石灰が
主体の上層スラリーを飛灰から選別することを特徴とす
るアルカリ性飛灰の処理方法としたものである。前記処
理方法で選別した上層スラリーは、固液分離し、分離し
た固形分に水酸化ナトリウム又は水酸化カリウムの水溶
液を加え、ｐＨ１２．５以上のアルカリ性として、含有
されているＰｂ、Ｚｎ及びＣｕを液相中に浸出し、分離
することができる。また、本発明では、アルカリ性飛灰
を無害化処理する方法において、特に消石灰の含有量が
少ない飛灰に対して、該飛灰に水を添加して含有する塩
分を水洗除去後、得られる飛灰に水酸化ナトリウム又は
水酸化カリウムの水溶液を加え、ｐＨ１２．５以上のア
ルカリ性として、含有されているＰｂ、Ｚｎ及びＣｕを
液相中に浸出し、分離するアルカリ性飛灰の処理方法と
したものである。In order to solve the above problems, the present invention provides a method for reducing the volume and harmlessness of alkaline fly ash by adding water to the fly ash to prepare a water slurry. By performing wet specific gravity separation of the prepared water slurry, the particle size is as small as several μm, and slaked lime having a low specific gravity is used as a method for treating alkaline fly ash, which is characterized in that the upper layer slurry is mainly separated from fly ash. Things. The upper layer slurry separated by the above-mentioned treatment method is subjected to solid-liquid separation, and an aqueous solution of sodium hydroxide or potassium hydroxide is added to the separated solid, and Pb, Zn and Cu contained as alkaline at pH 12.5 or more are added. It can leach into the liquid phase and separate. Further, in the present invention, in the method for detoxifying alkaline fly ash, especially for fly ash having a low content of slaked lime, the fly ash obtained by adding water to the fly ash and washing away the salt contained therein is removed. An alkaline fly ash treatment method in which an aqueous solution of sodium hydroxide or potassium hydroxide is added to the ash to make it alkaline with a pH of 12.5 or more, and the contained Pb, Zn and Cu are leached into the liquid phase and separated. It is.
【０００５】前記方法において、分離したアルカリ浸出
液は、硫化剤を添加して、液中のＰｂ、Ｚｎ及びＣｕを
硫化物として沈殿させて、回収することができる。硫化
剤としてＮａＳ又はＮａ2 Ｓを用いた場合においては、
硫化反応に伴ってＮａＯＨが生成するから、これをアル
カリ浸出に再利用することができる。また、前記の上層
スラリーからアルカリ浸出液を分離して得た固形分は、
乾燥後、粉砕して排ガス処理用のアルカリ剤として再利
用することができ、さらに、飛灰から上層スラリーを選
別分離した後の固形分又は飛灰を水洗後、直接アルカリ
浸出後の固形分は、水洗・乾燥して建設材料として用い
ることができる。さらに、排ガス中のダイオキシン、フ
ラン及び揮発性水銀を捕捉除去するために、粉末活性炭
を消石灰と一緒に吹き込む場合には、粉末活性炭は消石
灰と一緒に選別、回収され、リサイクル使用できる。In the above method, the separated alkaline leachate can be recovered by adding a sulphidizing agent to precipitate Pb, Zn and Cu in the liquor as sulfide. When NaS or Na 2 S is used as the sulphidizing agent,
Since NaOH is generated along with the sulfidation reaction, it can be reused for alkaline leaching. Further, the solid content obtained by separating the alkaline leachate from the upper layer slurry,
After drying, it can be pulverized and reused as an alkali agent for exhaust gas treatment.Furthermore, the solid content after separating and separating the upper layer slurry from the fly ash or the fly ash is washed with water, and the solid content after direct alkali leaching is It can be washed and dried and used as a construction material. Further, when powdered activated carbon is blown together with slaked lime in order to capture and remove dioxin, furan and volatile mercury in the exhaust gas, the powdered activated carbon is separated and collected together with slaked lime, and can be recycled.
【０００６】[0006]
【発明の実施の形態】本発明は、飛灰に含まれている過
剰の消石灰が飛灰の無害化処理と金属回収処理を難しく
している点に着目して鋭意に研鑽を重ねた結果、湿式比
重選鉱法によって消石灰を飛灰から選別できること、及
び飛灰からＰｂ、Ｚｎ、Ｃｕをアルカリ浸出できること
などの知見を見い出してなされたものである。次に、本
発明を詳細に説明する。まず、本発明によるアルカリ性
飛灰からの消石灰を分離する処理について述べる。前記
飛灰は、水スラリーに調合して湿式比重選鉱することに
より、消石灰等の水酸化物が主体の上層スラリーと、シ
リカ、アルミナや酸化鉄等の酸化物が主体の下層スラリ
ー（飛灰スラリー）とに選別する。BEST MODE FOR CARRYING OUT THE INVENTION The present invention focuses on the fact that excess slaked lime contained in fly ash makes it difficult to detoxify fly ash and to recover metal, and as a result of intensive studies, The present invention has been made based on the finding that slaked lime can be separated from fly ash by the wet specific gravity separation method and that Pb, Zn, and Cu can be leached from fly ash with alkali. Next, the present invention will be described in detail. First, a process for separating slaked lime from alkaline fly ash according to the present invention will be described. The fly ash is mixed with a water slurry and subjected to wet specific gravity separation to form an upper slurry mainly composed of hydroxide such as slaked lime and a lower slurry mainly composed of oxide such as silica, alumina and iron oxide (fly ash slurry). ).
【０００７】前記湿式比重選鉱法は水酸化物の消石灰
と、酸化物を主体とする飛灰との比重差及び粒径差を利
用したものである。具体的な方法としては例えば、予め
調合した飛灰スラリーに水を注入し、前記酸化物の粒子
が沈降していて消石灰粒子が浮遊している状態となるよ
うに、緩やかに攪拌しながら上層スラリーをデカンテー
ションする方法や、湿式サイクロン分級法を用いること
ができる。なお、湿式比重選鉱工程の前に、飛灰を水ス
ラリーに調合する工程を設ける目的は、飛灰中水溶解性
塩分（ＣａＣｌ2 、ＮａＣｌ等）を水洗除去し、また、
互いに凝結状態になった消石灰粒子と酸化物粒子とを単
体分離することである。湿式比重選鉱工程において用い
る装置としては例えば、１段のシックナー又は向流方式
の多段、好ましくは３段のシックナーを用いることがで
きる。The wet specific gravity ore separation method utilizes a difference in specific gravity and a difference in particle diameter between slaked lime of hydroxide and fly ash mainly composed of oxide. As a specific method, for example, water is poured into a fly ash slurry prepared in advance, and the upper slurry is stirred gently so that the oxide particles are settled and slaked lime particles are in a floating state. Can be used, or a wet cyclone classification method can be used. The purpose of providing a step of mixing fly ash into a water slurry before the wet specific gravity separation process is to wash and remove water-soluble salts (CaCl 2 , NaCl, etc.) in the fly ash,
The purpose is to separate slaked lime particles and oxide particles that have been coagulated from each other. As a device used in the wet specific gravity separation process, for example, a one-stage thickener or a multistage, preferably three-stage thickener of a countercurrent type can be used.
【０００８】次に、湿式比重選鉱工程から得られた上層
スラリーからの重金属の分離処理について述べる。前記
水酸化物主体の上層スラリーには、飛灰中の重金属の大
部分が含有されているから、該スラリーを固液分離した
固形分に、水酸化ナトリウム又は水酸化カリウムの水溶
液を加え、該固形分に含有されているＰｂ、Ｚｎ、Ｃｕ
をｐＨ１２．５以上のアルカリ性条件で液相中に浸出し
て分離する。このアルカリ浸出反応は次式（１）〜
（３）による。 Ｐｂ（ＯＨ）2 ＋ＮａＯＨ → ＮａＨＰｂＯ2 ＋Ｈ2 Ｏ （１） Ｚｎ（ＯＨ）2 ＋ＮａＯＨ → ＮａＨＺｎＯ2 ＋Ｈ2 Ｏ （２） Ｃｕ（ＯＨ）2 ＋ＮａＯＨ → ＮａＨＣｕＯ2 ＋Ｈ2 Ｏ （３）Next, a description will be given of a process of separating heavy metals from the upper slurry obtained from the wet specific gravity separation process. Since the hydroxide-based upper layer slurry contains most of heavy metals in fly ash, an aqueous solution of sodium hydroxide or potassium hydroxide is added to a solid content obtained by solid-liquid separation of the slurry. Pb, Zn, Cu contained in solid content
Is leached into the liquid phase under alkaline conditions of pH 12.5 or more and separated. This alkali leaching reaction is represented by the following formula (1)
According to (3). Pb (OH) 2 + NaOH → NaHPbO 2 + H 2 O (1) Zn (OH) 2 + NaOH → NaHZnO 2 + H 2 O (2) Cu (OH) 2 + NaOH → NaHCuO 2 + H 2 O (3)
【０００９】また、前記のアルカリによる重金属の浸出
処理は、飛灰にも適用できる。即ち、飛灰に水を添加し
て、飛灰中の水溶解性塩分を水洗除去した後、該飛灰に
そのまま水酸化ナトリウム又は水酸化カリウムの水溶液
を加えてｐＨ１２．５以上のアルカリ性とすることによ
り、飛灰中のＰｂ、Ｚｎ及びＣｕは液相中に浸出され、
液相を分離することにより、重金属分を含まない飛灰が
回収できる。そして、この飛灰も、重金属分をほとんど
含有しないため、建設材料として利用することができ
る。前記のアルカリ浸出により重金属分を除去した水酸
化物主体の上層スラリーの固形分は、乾燥、粉砕して排
ガス処理におけるアルカリ剤として再利用することがで
きる。The above-described leaching treatment of heavy metals with alkali can be applied to fly ash. That is, water is added to the fly ash, water-soluble salts in the fly ash are washed away with water, and an aqueous solution of sodium hydroxide or potassium hydroxide is directly added to the fly ash to make it alkaline at pH 12.5 or more. Thereby, Pb, Zn and Cu in the fly ash are leached into the liquid phase,
By separating the liquid phase, fly ash containing no heavy metal can be recovered. Since this fly ash hardly contains heavy metals, it can be used as a construction material. The solid content of the hydroxide-based upper layer slurry from which heavy metals have been removed by alkali leaching can be dried and pulverized and reused as an alkali agent in exhaust gas treatment.
【００１０】また、分離したアルカリ浸出液には、硫化
剤を加えて、液中のＰｂ、Ｚｎ、Ｃｕを硫化物として沈
殿させて回収する。その反応は、次式（４）〜（６）に
よる。 ＮａＨＰｂＯ2 ＋ＮａＨＳ → ＰｂＳ↓＋２ＮａＯＨ （４） ＮａＨＺｎＯ2 ＋ＮａＨＳ → ＺｎＳ↓＋２ＮａＯＨ （５） ＮａＨＣｕＯ2 ＋ＮａＨＳ → ＣｕＳ↓＋２ＮａＯＨ （６） なお、硫化後液は、鉱酸で中和処理した後に排水するこ
ともできるが、硫化反応に伴って水酸化ナトリウムが再
生されるので、アルカリ浸出液としてリサイクル使用す
ることが望ましい。一方、湿式比重選鉱工程で上層のス
ラリーを分離して得られた下層の飛灰スラリーは、固液
分離し、砂状の固形物を建築材料として利用するか、又
は一般廃棄物として埋め立て処分するか、又は溶融炉に
戻して再溶融することもできる。また、前記の処理でス
ラリーから固形分を分離したろ液、又は飛灰を水洗処理
した水洗液は、硫化反応工程に導入し、Ｐｂ、Ｚｎを硫
化物として回収する。硫化後液は中和処理して排水する
ことができる。図１及び図２に本発明のアルカリ飛灰の
処理方法のフローシートを示す。Further, a sulfurizing agent is added to the separated alkali leachate to precipitate and recover Pb, Zn, and Cu in the liquid as sulfides. The reaction is according to the following equations (4) to (6). NaHPbO 2 + NaHS → PbS ↓ + 2NaOH (4) NaHZnO 2 + NaHS → ZnS ↓ + 2NaOH (5) NaHCuO 2 + NaHS → CuS ↓ + 2NaOH (6) The liquid after sulfidation can be drained after neutralization with mineral acid. However, since sodium hydroxide is regenerated with the sulfurization reaction, it is desirable to recycle it as an alkaline leachate. On the other hand, the lower fly ash slurry obtained by separating the upper slurry in the wet specific gravity ore separation process is solid-liquid separated, and a sandy solid is used as a building material or landfilled as general waste. Alternatively, it can be returned to the melting furnace and re-melted. The filtrate obtained by separating the solid content from the slurry in the above treatment or the washing liquid obtained by washing the fly ash with water is introduced into a sulfurization reaction step, and Pb and Zn are recovered as sulfides. The liquid after sulfurization can be neutralized and drained. 1 and 2 show flow sheets of the method for treating alkaline fly ash according to the present invention.
【００１１】[0011]
【実施例】以下、本発明を実施例により具体的に説明す
る。 実施例１ 本発明により処理する処理対象飛灰として、都市ゴミの
焼却処理において発生したアルカリ性飛灰を用い、図１
のフローに従って試験を行った。各工程の実験条件及び
結果が下記の通りである。飛灰１．０ｋｇに水５リット
ルを加えて３０分間攪拌した後に、上層部をデカンテー
ションした。ついで、新たに水５リットルを加えてデカ
ンテーションし、この操作を２回繰り返した（スラリー
調合後のデカンテーションと合わせると３回のデカンテ
ーションとなる）。ついで、上層スラリーと下層スラリ
ーをそれぞれろ過、固形分を１０５℃で乾燥して重量を
測った。The present invention will be described below in more detail with reference to examples. Example 1 As the fly ash to be treated according to the present invention, alkaline fly ash generated in the incineration of municipal waste was used.
The test was performed according to the flow of The experimental conditions and results of each step are as follows. After 5 liters of water was added to 1.0 kg of fly ash and stirred for 30 minutes, the upper layer was decanted. Then, 5 liters of water was newly added and decantation was carried out, and this operation was repeated twice (together with decantation after slurry preparation, three decantations were obtained). Next, the upper layer slurry and the lower layer slurry were respectively filtered, and the solid content was dried at 105 ° C. and weighed.
【００１２】下層固形分、即ち処理後の飛灰分を成分分
析、アルカリ度測定とＰｂ溶出試験に供し、一方、上層
固形分を成分分析、アルカリ度測定とＰｂ溶出試験と次
のアルカリ浸出工程に供した。ここで、固形分のアルカ
リ度は、対象固形分５ｇに純水５０ｍｌを加えたスラリ
ーのｐＨをｐＨ７．０にまで中和した時の１Ｎ塩酸消費
量（ｍｌ）である。処理後飛灰の溶出試験は、環境庁告
示１３号に準じて行った。表１に重量、Ｐｂ溶出量、ア
ルカリ度及び化学成分分析結果を示し、アルカリ度測定
における各固形分の酸中和曲線を図３に示す。前記スラ
リーのろ液に、理論当量の１．２倍量の水硫化ソーダを
加えた所、上澄み液のＰｂ、Ｚｎ、Ｃｕ残留濃度がいず
れも０．１ｍｇ／リットル以下となった。The lower layer solid content, ie, the fly ash after the treatment, is subjected to component analysis, alkalinity measurement and Pb elution test, while the upper layer solid content is subjected to component analysis, alkalinity measurement, Pb elution test and the next alkali leaching step. Provided. Here, the alkalinity of the solid content is 1N hydrochloric acid consumption (ml) when the pH of a slurry obtained by adding 50 ml of pure water to 5 g of the target solid content is neutralized to pH 7.0. The dissolution test of the fly ash after the treatment was performed according to the notification of the Environment Agency No. 13. Table 1 shows the weight, the elution amount of Pb, the alkalinity, and the results of chemical component analysis. FIG. 3 shows the acid neutralization curve of each solid in the alkalinity measurement. When 1.2 times the theoretical equivalent amount of sodium hydrosulfide was added to the filtrate of the slurry, the residual concentrations of Pb, Zn, and Cu in the supernatant liquid were all 0.1 mg / liter or less.
【００１３】湿式比重選鉱の結果、表１に見られるよう
に、飛灰が３分の１（原飛灰１０００ｇに対し、処理飛
灰２９６ｇ）に減量化し、Ｐｂの溶出も０．３ｍｇ／リ
ットルの埋立基準値を下回り無害化した。また、表１及
び図３から分かるように、９４％の消石灰分が上層固形
分に移行していた。続くアルカリ浸出工程では、上層固
形分を５重量％スラリーに調整し、ｐＨ１３．５、温度
４０℃の一定として１時間攪拌し、反応せしめた。アル
カリ剤として水酸化ナトリウムを用いた。アルカリ浸出
の結果、Ｐｂ、Ｚｎ、Ｃｕの浸出率がそれぞれ９６％、
８４％、４７％に達した。ついで、スラリーをろ過し、
浸出残さを乾燥して成分分析に供し、分析結果を表１に
示した。ろ液には理論当量の１．０倍量の水硫化ソーダ
を加え、ろ液中のＰｂ、Ｚｎ、Ｃｕを硫化物として沈殿
させて回収した。また、生成した硫化物の沈降性が良好
であった。[0013] As a result of the wet specific gravity separation, as shown in Table 1, fly ash was reduced to one third (1,000 g of raw fly ash, 296 g of treated fly ash), and the elution of Pb was 0.3 mg / liter. Below the landfill standard value. As can be seen from Table 1 and FIG. 3, 94% of slaked lime was transferred to the upper layer solids. In the subsequent alkaline leaching step, the solid content of the upper layer was adjusted to a 5% by weight slurry, and the mixture was stirred for 1 hour at a constant pH of 13.5 and a temperature of 40 ° C. to react. Sodium hydroxide was used as an alkaline agent. As a result of alkali leaching, the leaching rates of Pb, Zn, and Cu were 96%, respectively.
It reached 84% and 47%. Then, filter the slurry,
The leach residue was dried and subjected to component analysis. The analysis results are shown in Table 1. 1.0 times the theoretical equivalent amount of sodium hydrosulfide was added to the filtrate, and Pb, Zn, and Cu in the filtrate were precipitated and recovered as sulfide. In addition, the sedimentation of the generated sulfide was good.
【００１４】[0014]
【表１】 * ろ液に溶解した塩分は４１０ｇであった。[Table 1] * 410 g of salt dissolved in the filtrate.
【００１５】[0015]
【発明の効果】本発明によれば、次のような効果を奏す
ることができる。 （１）飛灰を減容すると同時に、無害化することができ
る。 （２）選別された消石灰が再利用できる。 （３）飛灰に含まれたＰｂ、Ｚｎ、Ｃｕが硫化物の形で
回収できる。 （４）飛灰中の水溶性塩分を水洗除去し、重金属をアル
カリ浸出することにより、飛灰を有効利用できる。According to the present invention, the following effects can be obtained. (1) The fly ash can be made harmless while reducing its volume. (2) Sorted slaked lime can be reused. (3) Pb, Zn, and Cu contained in fly ash can be recovered in the form of sulfide. (4) The fly ash can be effectively used by washing and removing water-soluble salts in the fly ash and leaching heavy metals with alkali.
【図１】本発明によるアルカリ性飛灰処理方法の一例を
示すフローシート。FIG. 1 is a flow sheet showing an example of an alkaline fly ash treatment method according to the present invention.
【図２】本発明によるアルカリ性飛灰処理方法の他の例
を示すフローシート。FIG. 2 is a flow sheet showing another example of the alkaline fly ash treatment method according to the present invention.
【図３】実施例１の原飛灰、処理飛灰及び上層固形分の
酸中和曲線を示すグラフ。FIG. 3 is a graph showing an acid neutralization curve of raw fly ash, treated fly ash, and upper layer solid of Example 1.
Claims (6)
処理方法において、該飛灰に水を添加して水スラリーを
調合し、調合した水スラリーを湿式比重選鉱することに
より、粒径が細かくて、比重の軽い消石灰が主体の上層
スラリーを飛灰から選別することを特徴とするアルカリ
性飛灰の処理方法。In a treatment method for reducing and detoxifying alkaline fly ash, water is added to the fly ash to prepare a water slurry, and the prepared water slurry is subjected to wet specific gravity ore separation to obtain a particle size. A method for treating alkaline fly ash, wherein the finely divided slaked lime having a low specific gravity is used to separate the upper slurry from fly ash.
し、分離した固形分に水酸化ナトリウム又は水酸化カリ
ウムの水溶液を加え、ｐＨ１２．５以上のアルカリ性と
して、含有されているＰｂ、Ｚｎ及びＣｕを液相中に浸
出し、分離することを特徴とする請求項１に記載のアル
カリ性飛灰の処理方法。2. The selected upper layer slurry is subjected to solid-liquid separation, and an aqueous solution of sodium hydroxide or potassium hydroxide is added to the separated solid, so that Pb, Zn, The method for treating alkaline fly ash according to claim 1, wherein Cu is leached into a liquid phase and separated.
おいて、該飛灰に水を添加して含有する塩分を水洗除去
後、得られる飛灰に水酸化ナトリウム又は水酸化カリウ
ムの水溶液を加え、ｐＨ１２．５以上のアルカリ性とし
て、含有されているＰｂ、Ｚｎ及びＣｕを液相中に浸出
し、分離することを特徴とするアルカリ性飛灰の処理方
法。3. A method for detoxifying alkaline fly ash, comprising adding water to the fly ash to remove salts contained therein, washing the resulting fly ash with an aqueous solution of sodium hydroxide or potassium hydroxide, A method for treating alkaline fly ash, comprising leaching and separating Pb, Zn and Cu contained in a liquid phase as alkaline having a pH of 12.5 or more.
を添加して、液中のＰｂ、Ｚｎ及びＣｕを硫化物として
沈殿させて、回収することを特徴とする請求項２又は３
記載のアルカリ性飛灰の処理方法。4. The separated alkaline leachate is recovered by adding a sulfurizing agent to precipitate Pb, Zn and Cu in the solution as sulfides.
The method for treating alkaline fly ash according to the above.
は、乾燥後、粉砕して排ガス処理に再利用することを特
徴とする請求項２に記載のアルカリ性飛灰の処理方法。5. The method for treating alkaline fly ash according to claim 2, wherein the solid content obtained by separating the alkaline leachate is dried, pulverized, and reused in exhaust gas treatment.
を選別分離した後の固形分又は請求項３記載のアルカリ
浸出液を分離した固形分は、水洗・乾燥して建設材料と
して利用することを特徴とするアルカリ性飛灰の処理方
法。6. The solid content obtained by separating and separating the upper layer slurry from the fly ash according to claim 1 or the solid content obtained by separating the alkaline leachate according to claim 3 is washed and dried to be used as a construction material. A method for treating alkaline fly ash, comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17717096A JP3640274B2 (en) | 1996-06-19 | 1996-06-19 | Alkaline fly ash treatment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17717096A JP3640274B2 (en) | 1996-06-19 | 1996-06-19 | Alkaline fly ash treatment method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH105736A true JPH105736A (en) | 1998-01-13 |
| JP3640274B2 JP3640274B2 (en) | 2005-04-20 |
Family
ID=16026417
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17717096A Expired - Fee Related JP3640274B2 (en) | 1996-06-19 | 1996-06-19 | Alkaline fly ash treatment method |
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| Country | Link |
|---|---|
| JP (1) | JP3640274B2 (en) |
Cited By (7)
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|---|---|---|---|---|
| US6500395B1 (en) * | 1999-09-21 | 2002-12-31 | Institut National De La Recherche Scientifique | Method for removing metals from air pollution control residues |
| JP2003001218A (en) * | 2001-06-21 | 2003-01-07 | Taiheiyo Cement Corp | Method for treating waste having high chlorine and lead contents |
| JP2005238102A (en) * | 2004-02-26 | 2005-09-08 | Nishimatsu Constr Co Ltd | Method for cleaning contaminated soil |
| JP2006255501A (en) * | 2005-03-15 | 2006-09-28 | Mitsui Eng & Shipbuild Co Ltd | Method of removing heavy metal in flying ash |
| JP2009131792A (en) * | 2007-11-30 | 2009-06-18 | Chugoku Electric Power Co Inc:The | Fly ash balloon recovering method and system |
| JP2009226279A (en) * | 2008-03-21 | 2009-10-08 | Taiheiyo Cement Corp | Method of treating microdust containing calcium component and lead component |
| CN104495892A (en) * | 2014-12-06 | 2015-04-08 | 中国铝业股份有限公司 | Method for removing silicon from alpha-alumina micropowder |
-
1996
- 1996-06-19 JP JP17717096A patent/JP3640274B2/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6500395B1 (en) * | 1999-09-21 | 2002-12-31 | Institut National De La Recherche Scientifique | Method for removing metals from air pollution control residues |
| JP2003001218A (en) * | 2001-06-21 | 2003-01-07 | Taiheiyo Cement Corp | Method for treating waste having high chlorine and lead contents |
| JP4549579B2 (en) * | 2001-06-21 | 2010-09-22 | 太平洋セメント株式会社 | Waste treatment method with high chlorine and lead content |
| JP2005238102A (en) * | 2004-02-26 | 2005-09-08 | Nishimatsu Constr Co Ltd | Method for cleaning contaminated soil |
| JP2006255501A (en) * | 2005-03-15 | 2006-09-28 | Mitsui Eng & Shipbuild Co Ltd | Method of removing heavy metal in flying ash |
| JP2009131792A (en) * | 2007-11-30 | 2009-06-18 | Chugoku Electric Power Co Inc:The | Fly ash balloon recovering method and system |
| JP2009226279A (en) * | 2008-03-21 | 2009-10-08 | Taiheiyo Cement Corp | Method of treating microdust containing calcium component and lead component |
| CN104495892A (en) * | 2014-12-06 | 2015-04-08 | 中国铝业股份有限公司 | Method for removing silicon from alpha-alumina micropowder |
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|---|---|
| JP3640274B2 (en) | 2005-04-20 |
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