JP2000054038A - Treatment of calcium-containing incineration fly ash and molten fly ash - Google Patents
Treatment of calcium-containing incineration fly ash and molten fly ashInfo
- Publication number
- JP2000054038A JP2000054038A JP23661998A JP23661998A JP2000054038A JP 2000054038 A JP2000054038 A JP 2000054038A JP 23661998 A JP23661998 A JP 23661998A JP 23661998 A JP23661998 A JP 23661998A JP 2000054038 A JP2000054038 A JP 2000054038A
- Authority
- JP
- Japan
- Prior art keywords
- fly ash
- zinc
- solid
- lead
- residue
- 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 36
- 239000011575 calcium Substances 0.000 title abstract description 10
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 title abstract description 8
- 229910052791 calcium Inorganic materials 0.000 title abstract description 8
- 239000011701 zinc Substances 0.000 claims abstract description 37
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 36
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 36
- 229910001385 heavy metal Inorganic materials 0.000 claims abstract description 33
- 239000007788 liquid Substances 0.000 claims abstract description 30
- 238000000034 method Methods 0.000 claims abstract description 28
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims abstract description 22
- 239000000920 calcium hydroxide Substances 0.000 claims abstract description 22
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims abstract description 22
- 235000011116 calcium hydroxide Nutrition 0.000 claims abstract description 22
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 16
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims abstract description 14
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 12
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims abstract description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000001110 calcium chloride Substances 0.000 claims abstract description 8
- 229910001628 calcium chloride Inorganic materials 0.000 claims abstract description 8
- 239000007791 liquid phase Substances 0.000 claims abstract description 8
- 150000003839 salts Chemical class 0.000 claims abstract description 8
- 239000003513 alkali Substances 0.000 claims abstract description 7
- 235000019270 ammonium chloride Nutrition 0.000 claims abstract description 7
- 230000002378 acidificating effect Effects 0.000 claims abstract description 4
- 229910052751 metal Inorganic materials 0.000 claims abstract description 3
- 239000002184 metal Substances 0.000 claims abstract description 3
- 150000003568 thioethers Chemical class 0.000 claims abstract 2
- 238000000926 separation method Methods 0.000 claims description 25
- 238000002844 melting Methods 0.000 claims description 10
- 230000008018 melting Effects 0.000 claims description 10
- 239000002244 precipitate Substances 0.000 claims description 10
- 239000002002 slurry Substances 0.000 claims description 8
- 238000003756 stirring Methods 0.000 claims description 8
- 239000007864 aqueous solution Substances 0.000 claims description 6
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 3
- 150000004692 metal hydroxides Chemical class 0.000 claims description 2
- 230000003381 solubilizing effect Effects 0.000 abstract description 3
- 150000004679 hydroxides Chemical class 0.000 abstract description 2
- 150000002739 metals Chemical class 0.000 abstract description 2
- 239000010802 sludge Substances 0.000 abstract 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 239000000706 filtrate Substances 0.000 description 7
- 239000000243 solution Substances 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000002351 wastewater Substances 0.000 description 4
- 238000003723 Smelting Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000003672 processing method Methods 0.000 description 3
- 150000004763 sulfides Chemical class 0.000 description 3
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- HYHCSLBZRBJJCH-UHFFFAOYSA-M sodium hydrosulfide Chemical compound [Na+].[SH-] HYHCSLBZRBJJCH-UHFFFAOYSA-M 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000002956 ash Substances 0.000 description 1
- 229940043430 calcium compound Drugs 0.000 description 1
- 150000001674 calcium compounds Chemical class 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- -1 that is Chemical compound 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
- 238000004056 waste incineration Methods 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Processing Of Solid Wastes (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、カルシウムを含有
する飛灰の処理方法に係り、特に、都市ゴミ焼却工場や
産業廃棄物焼却工場等における焼却炉及び溶融炉から発
生する排ガスに、乾式中和処理剤として消石灰を噴霧し
たバグフィルター飛灰からの鉛、亜鉛、等の重金属を回
収することができる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 containing calcium, and more particularly to a method for treating waste gas generated from incinerators and melting furnaces in municipal garbage incineration plants and industrial waste incineration plants. The present invention relates to a fly ash treatment method capable of recovering heavy metals such as lead, zinc, and the like from a bag filter fly ash sprayed with slaked lime as a sum treatment agent.
【0002】[0002]
【従来の技術】これまで焼却炉及び溶融炉から発生する
鉛、亜鉛等の重金属を含む飛灰からの重金属の回収方法
としては、飛灰を酸で溶解し、鉛以外の重金属を液相に
溶出させ、鉛を主成分とする残渣を回収する工程と、上
記液相に硫化剤を添加することで、亜鉛を主とする硫化
沈殿物を回収していた(特開平8−141539号公報
参照)。ところが、現在の焼却炉又は溶融炉の排ガス処
理は、排ガスに消石灰を直接噴霧する乾式中和処理が主
流となっている。したがって、乾式排ガス処理方式で得
られる飛灰は、必然的に消石灰、すなわちカルシウムの
含有率が高くなっている。上記した従来法の重金属回収
プロセスを、消石灰含有飛灰に適用すると、硫酸と消石
灰中のカルシウムが反応して石膏を生じ、回収物の重金
属品位が低下してしまうという問題があった。2. Description of the Related Art Conventionally, as a method for recovering heavy metals from fly ash containing heavy metals such as lead and zinc generated from incinerators and melting furnaces, fly ash is dissolved with an acid, and heavy metals other than lead are converted into a liquid phase. A process of eluting and recovering a residue containing lead as a main component, and adding a sulfide agent to the liquid phase to recover a sulfide precipitate mainly containing zinc (see Japanese Patent Application Laid-Open No. 8-141439). ). However, the current mainstream of exhaust gas treatment for incinerators or melting furnaces is dry neutralization treatment in which slaked lime is directly sprayed on exhaust gas. Therefore, fly ash obtained by the dry exhaust gas treatment method necessarily has a high content of slaked lime, that is, calcium. When the above-mentioned conventional heavy metal recovery process is applied to slaked lime-containing fly ash, sulfuric acid and calcium in slaked lime react to produce gypsum, and the quality of the recovered heavy metal is reduced.
【0003】[0003]
【発明が解決しようとする課題】そこで、本発明は、上
述した従来の技術の問題点を解決し、消石灰を含有して
いる飛灰中に含まれている鉛、亜鉛等の重金属を安定な
形で高品位に分離することができる焼却炉及び溶融炉か
らの飛灰中の重金属回収方法を提供することを課題とす
る。SUMMARY OF THE INVENTION Accordingly, the present invention solves the above-mentioned problems of the prior art, and stabilizes heavy metals such as lead and zinc contained in fly ash containing slaked lime. It is an object of the present invention to provide a method for recovering heavy metals in fly ash from an incinerator and a melting furnace, which can be separated into high-quality incinerators.
【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、消石灰を噴霧した焼却炉及び溶融炉か
ら発生する鉛、亜鉛を含む重金属類と、塩化カルシウム
を含む塩類及び未反応の消石灰を含有する飛灰の処理方
法において、前記飛灰に希塩酸を添加して泥状化し、塩
化カルシウムを含む塩類と亜鉛の大部分を溶出させた
後、固液分離する第一工程と、得られた残渣に塩化アン
モニウム水溶液を加えて再泥状化させることにより、未
反応の消石灰を可溶化させた後、固液分離し、鉛を主成
分とする重金属を含む残渣を得る第二工程からなる飛灰
の処理方法としたものである。In order to solve the above-mentioned problems, according to the present invention, heavy metals containing lead and zinc generated from an incinerator and a melting furnace sprayed with slaked lime, salts containing calcium chloride, and salts and unreacted materials containing calcium chloride In the method for treating fly ash containing slaked lime, the fly ash is added with diluted hydrochloric acid to form a muddy state, and after eluting most of salts and zinc containing calcium chloride, a first step of solid-liquid separation, The second step of solubilizing unreacted slaked lime by adding an aqueous solution of ammonium chloride to the obtained residue to re-slurry, and then performing solid-liquid separation to obtain a residue containing a heavy metal mainly composed of lead. This is a method for treating fly ash.
【0005】前記処理方法において、第一工程及び第二
工程の固液分離で得られた液相は、アルカリ剤を添加し
てアルカリ性とし、亜鉛を主成分とする重金属の水酸化
物を生成させて固液分離するか、又は、固液分離せず
に、さらに硫化剤を添加して残りの重金属を硫化物とし
て沈殿させ、これらの沈殿物を固液分離することができ
る。また、前記処理方法において、第二工程で得られた
残渣は、水溶液中に再泥状化し、硫酸を添加して酸性条
件に調節し、鉛以外の金属を溶出させて固液分離し、鉛
を含有する残渣を得る第三工程からなることとすること
ができる。さらに、本発明では、前記第一、第二及び第
三工程の固液分離で得られた液相は、それらを混合し攪
拌させながら、アルカリ剤を添加してアルカリ性とし、
さらに硫化剤を飛灰中の亜鉛の当量以上に添加し、亜鉛
を主とする重金属類の水酸化沈殿物及び硫化沈殿物を生
成させる第四工程からなることとすることができる。[0005] In the above treatment method, the liquid phase obtained by the solid-liquid separation in the first step and the second step is made alkaline by adding an alkali agent to form a heavy metal hydroxide mainly composed of zinc. Alternatively, solid-liquid separation may be performed, or the solid-liquid separation may be performed by further adding a sulfurizing agent to precipitate the remaining heavy metals as sulfides. In the above treatment method, the residue obtained in the second step is re-mudged in an aqueous solution, adjusted to acidic conditions by adding sulfuric acid, eluted with metals other than lead, and subjected to solid-liquid separation. And a third step of obtaining a residue containing Furthermore, in the present invention, the liquid phase obtained by the solid-liquid separation in the first, second and third steps is made alkaline by adding an alkali agent while mixing and stirring them.
The method may further comprise a fourth step of adding a sulfurizing agent to an equivalent or more of zinc in the fly ash to produce a hydroxide precipitate and a sulfurized precipitate of heavy metals mainly containing zinc.
【0006】[0006]
【発明の実施の形態】本発明は、消石灰を噴霧した焼却
炉及び溶融炉から発生する鉛、亜鉛等の重金属類と、塩
化カルシウム及び未反応の消石灰を含有する飛灰の処理
方法であって、前記飛灰を希塩酸を用いて塩化カルシウ
ム等の塩類と亜鉛の大部分を溶出させた後、固液分離す
る第一工程と、得られた残渣を塩化アンモニウム水溶液
中で再泥状化(リパルプ)させることにより、未反応の
消石灰を可溶化させた後、鉛を主成分とする重金属を含
む残渣を固液分離する第二工程からなることを特徴とす
る焼却炉及び溶融炉からの飛灰の処理方法である。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating fly ash containing heavy metals such as lead and zinc generated from an incinerator and a melting furnace sprayed with slaked lime, calcium chloride and unreacted slaked lime. The fly ash is eluted with dilute hydrochloric acid to elute most of salts such as calcium chloride and zinc, followed by solid-liquid separation, and the resulting residue is re-mudged in an aqueous ammonium chloride solution (repulpable ), Solubilizing the unreacted slaked lime, and then solid-liquid separation of the residue containing heavy metals containing lead as a main component. Processing method.
【0007】以下、本発明を詳細に説明する。まず、都
市ゴミ焼却工場における焼却灰の溶融処理の際に発生す
る消石灰添加溶融飛灰を、希塩酸中に加えてリパルプ
し、室温で攪拌する。好ましくは、攪拌時間は30分以
上とするのが良い。次に、上記スラリーを固液分離し、
Cl化合物やCa化合物及びZn化合物を含むろ液と、
鉛を主とする重金属類含有残渣とに分離する(第一工
程)。上記のようにして得られた残渣を、飛灰中のカル
シウムに対して当量以上の塩化アンモニウム水溶液に加
えて攪拌し、未反応の消石灰を可溶化させることで、残
渣の鉛含有率を向上させ、鉛含有残渣を得る(第二工
程)。この工程での消石灰と塩化アンモニウムの反応
は、次式のとおりである。 Ca(OH)2 +2NH4 Cl → CaCl2 +2H
2 O+2NH3 この反応で生じたアンモニアガスは、焼却炉又は溶融炉
の排ガスラインに移送し、乾式NOx除去剤として再利
用する。Hereinafter, the present invention will be described in detail. First, slaked lime-added molten fly ash generated during the melting treatment of incinerated ash in an urban refuse incineration plant is added to dilute hydrochloric acid, repulped, and stirred at room temperature. Preferably, the stirring time is 30 minutes or more. Next, the slurry is subjected to solid-liquid separation,
A filtrate containing a Cl compound, a Ca compound, and a Zn compound;
It is separated into heavy metal-containing residues mainly composed of lead (first step). The residue obtained as described above is added to an aqueous solution of ammonium chloride in an amount equivalent to or more than calcium in the fly ash, and the mixture is stirred to solubilize unreacted slaked lime, thereby improving the lead content of the residue. To obtain a lead-containing residue (second step). The reaction between slaked lime and ammonium chloride in this step is as follows. Ca (OH) 2 + 2NH 4 Cl → CaCl 2 + 2H
2 O + 2 NH 3 The ammonia gas generated by this reaction is transferred to an exhaust gas line of an incinerator or melting furnace and reused as a dry NOx remover.
【0008】また、亜鉛は、前記第一工程及び第二工程
の固液分離で得られた液相を水酸化ナトリウム等のアル
カリ剤を添加してアルカリ性とし、亜鉛を主成分とする
重金属の水酸化物を生成させて固液分離するか、又は、
固液分離せずに、さらに水硫化ナトリウム等の硫化剤を
添加して残りの重金属を硫化物として沈殿させ、これら
の沈殿物を固液分離して回収する。さらに、鉛含有残渣
の鉛品位を上げるためには、第二工程の残渣を水に溶解
させてスラリーとし、このスラリーを室温で攪拌しなが
ら、硫酸を添加して酸性条件下で、鉛以外の重金属を可
溶化させる。スラリー中の鉛は、硫酸沈殿物として回収
する(第三工程)。[0008] Zinc is made alkaline by adding an alkali agent such as sodium hydroxide to the liquid phase obtained by the solid-liquid separation in the first step and the second step. Generate oxides and perform solid-liquid separation, or
Instead of solid-liquid separation, a sulfurizing agent such as sodium hydrosulfide is further added to precipitate the remaining heavy metals as sulfides, and these precipitates are collected by solid-liquid separation. Furthermore, in order to raise the lead quality of the lead-containing residue, the residue of the second step is dissolved in water to form a slurry. Solubilize heavy metals. The lead in the slurry is recovered as a sulfuric acid precipitate (third step).
【0009】前記の亜鉛の回収は、第一、第二及び第三
工程で得られたろ液を混合した後、攪拌しながら水酸化
ナトリウム等のアルカリ剤を添加して、アルカリ条件下
で水硫化ナトリウム等の硫化剤を添加することにより、
亜鉛等の重金属を水酸化物及び硫化物として沈殿させ、
この溶液を固液分離して行う(第四工程)。上記のよう
に、本発明においては、消石灰含有飛灰に含まれている
重金属を、添加した消石灰に妨害されること無く、高品
位の鉛含有残渣、亜鉛含有残渣に分離回収可能であり、
これら回収物は、非鉄製錬の二次原料として使用するこ
とが可能となる。The recovery of zinc is carried out by mixing the filtrates obtained in the first, second and third steps, adding an alkali agent such as sodium hydroxide while stirring, and hydrolyzing under alkaline conditions. By adding a sulfurizing agent such as sodium,
Precipitating heavy metals such as zinc as hydroxides and sulfides,
This solution is subjected to solid-liquid separation (fourth step). As described above, in the present invention, heavy metals contained in slaked lime-containing fly ash can be separated and recovered into high-grade lead-containing residues and zinc-containing residues without being disturbed by the added slaked lime,
These recovered materials can be used as secondary raw materials for non-ferrous smelting.
【0010】[0010]
【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 図1に本発明の処理方法の全体のフロー工程図を示す。
この実施例は、図1のフローに従って焼却炉及び溶融炉
の飛灰を処理したものである。1N塩酸1リットルに、
飛灰100gを加えて30分間攪拌する。このスラリー
を固液分離して、重金属類を含有する残渣とCl化合物
を含むろ液に分け、得られた残渣を、1.6Nの塩化
アンモニウム水溶液1リットルに添加し、30分攪拌抽
出する。このスラリーを固液分離することで、カルシウ
ム、亜鉛を含む水溶液と鉛、亜鉛を含む残渣とに分離
できる。The present invention will be described below in more detail with reference to examples. Example 1 FIG. 1 shows an overall flow process diagram of the processing method of the present invention.
In this embodiment, fly ash in an incinerator and a melting furnace is treated according to the flow shown in FIG. 1 liter of 1N hydrochloric acid
100 g of fly ash is added and stirred for 30 minutes. This slurry is subjected to solid-liquid separation, separated into a residue containing heavy metals and a filtrate containing a Cl compound, and the obtained residue is added to 1 liter of a 1.6 N aqueous ammonium chloride solution and extracted with stirring for 30 minutes. This slurry can be separated into an aqueous solution containing calcium and zinc and a residue containing lead and zinc by solid-liquid separation.
【0011】ここで得られた残渣を、水1リットルを用
いてリパルプし、その溶液に硫酸を添加して、酸性条件
を維持しながら少なくとも30分は攪拌を続ける。ここ
で鉛を沈殿させる。次いで、このスラリーを固液分離す
ることで、鉛以外の重金属を含有するろ液と鉛含有残
渣に分けられる。先に得られたろ液、ろ液、ろ液
を合わせて、そこに中和剤として5Nの水酸化ナトリウ
ム溶液を添加し、アルカリ条件に調整する。pH調整後
は少なくとも30分間は攪拌を続け、亜鉛等の水酸化物
沈殿物を生成させる。ついで、水硫化ナトリウムを15
g(飛灰に含まれる亜鉛の当量以上)添加し、少なくと
も30分以上攪拌維持し、亜鉛以外の重金属類を硫化沈
殿物にする。この溶液を固液分離することで、亜鉛含有
残渣と総合排水を得ることができる。The residue obtained here is repulped with 1 liter of water, sulfuric acid is added to the solution, and stirring is continued for at least 30 minutes while maintaining acidic conditions. Here, lead is precipitated. Next, this slurry is separated into a filtrate containing heavy metals other than lead and a lead-containing residue by solid-liquid separation. The filtrate obtained above, the filtrate, and the filtrate are combined, and a 5N sodium hydroxide solution as a neutralizing agent is added thereto, and the mixture is adjusted to alkaline conditions. After the pH adjustment, stirring is continued for at least 30 minutes to form a hydroxide precipitate such as zinc. Then, add sodium hydrosulfide to 15
g (equivalent of zinc contained in fly ash) is added, and stirring is maintained for at least 30 minutes to convert heavy metals other than zinc into sulfide precipitates. By subjecting this solution to solid-liquid separation, a zinc-containing residue and comprehensive wastewater can be obtained.
【0012】表1に、従来法と本法による処理を行った
場合の、鉛含有残渣、亜鉛含有残渣、総合排水の分析値
を記す。Table 1 shows the analysis values of the lead-containing residue, the zinc-containing residue, and the total wastewater when the treatment was carried out by the conventional method and the present method.
【表1】 [Table 1]
【0013】表1から分かるように、従来法による処理
では、鉛含有残渣中にはカルシウム分が約25%含まれ
ているため、鉛の含有率が約4%となっている。また亜
鉛含有残渣の亜鉛含有率は40%となった。しかし、本
発明を用いた場合では、鉛含有残渣中の鉛含有率は2
6.1%、亜鉛含有残渣中の亜鉛含有率は72.1%と
なり、これらは従来法と比べて高い品位であり、非鉄製
錬二次原料として使用することが十分可能である。さら
に、総合排水は排水基準を下回っており、河川や海など
に直接放流可能である。As can be seen from Table 1, in the conventional treatment, the lead-containing residue contains about 25% calcium, so that the lead content is about 4%. The zinc content of the zinc-containing residue was 40%. However, when the present invention is used, the lead content in the lead-containing residue is 2%.
6.1%, and the zinc content in the zinc-containing residue is 72.1%. These are higher in quality than the conventional method, and can be sufficiently used as a secondary nonferrous smelting raw material. In addition, general wastewater is below the wastewater standard and can be discharged directly to rivers and the sea.
【0014】[0014]
【発明の効果】本発明によれば、消石灰含有飛灰に含ま
れている重金属を、カルシウム化合物に妨害されること
無く、高品位の鉛含有残渣、亜鉛含有残渣として分離可
能であり、これら回収物は、非鉄製錬の二次原料として
使用することが可能となる。According to the present invention, heavy metals contained in slaked lime-containing fly ash can be separated as high-quality lead-containing residues and zinc-containing residues without being hindered by calcium compounds. The product can be used as a secondary material for non-ferrous smelting.
【図1】本発明の処理方法の一例を示すフロー工程図。FIG. 1 is a flowchart showing an example of a processing method according to the present invention.
Claims (4)
発生する鉛、亜鉛を含む重金属類と、塩化カルシウムを
含む塩類及び未反応の消石灰を含有する飛灰の処理方法
において、前記飛灰に希塩酸を添加して泥状化し、塩化
カルシウムを含む塩類と亜鉛の大部分を溶出させた後、
固液分離する第一工程と、得られた残渣に塩化アンモニ
ウム水溶液を加えて再泥状化させることにより、未反応
の消石灰を可溶化させた後、固液分離し、鉛を主成分と
する重金属を含む残渣を得る第二工程からなることを特
徴とする飛灰の処理方法。1. A method for treating fly ash containing heavy metals containing lead and zinc, salts containing calcium chloride, and unreacted slaked lime generated from an incinerator and a melting furnace sprayed with slaked lime. After adding dilute hydrochloric acid to make muddy and elute most of salts and zinc containing calcium chloride,
The first step of solid-liquid separation, and by adding an aqueous solution of ammonium chloride to the obtained residue to re-slurry, solubilize unreacted slaked lime, and then perform solid-liquid separation, and mainly contain lead A method for treating fly ash, comprising a second step of obtaining a residue containing a heavy metal.
得られた液相は、アルカリ剤を添加してアルカリ性と
し、亜鉛を主成分とする重金属の水酸化物を生成させて
固液分離するか、又は、固液分離せずに、さらに硫化剤
を添加して残りの重金属を硫化物として沈殿させ、これ
らの沈殿物を固液分離することを特徴とする請求項1に
記載の飛灰の処理方法。2. The liquid phase obtained by the solid-liquid separation in the first step and the second step is made alkaline by adding an alkali agent, and solidified by generating a heavy metal hydroxide containing zinc as a main component. 2. The method according to claim 1, wherein the liquid heavy is separated or solid-liquid separated, and a sulfurizing agent is further added to precipitate remaining heavy metals as sulfides, and these precipitates are subjected to solid-liquid separation. Fly ash treatment method.
中に再泥状化し、硫酸を添加して酸性条件に調節し、鉛
以外の金属を溶出させて固液分離し、鉛を含有する残渣
を得る第三工程からなることを特徴とする請求項1記載
の飛灰の処理方法。3. The residue obtained in the second step is re-slurried in an aqueous solution, adjusted to an acidic condition by adding sulfuric acid, and eluted with a metal other than lead to perform solid-liquid separation. The method for treating fly ash according to claim 1, comprising a third step of obtaining a contained residue.
で得られた液相は、それらを混合し攪拌させながら、ア
ルカリ剤を添加してアルカリ性とし、さらに硫化剤を飛
灰中の亜鉛の当量以上に添加し、亜鉛を主とする重金属
類の水酸化沈殿物及び硫化沈殿物を生成させる第四工程
からなることを特徴とする請求項3記載の飛灰の処理方
法。4. A liquid phase obtained by the solid-liquid separation in the first, second and third steps is made alkaline by adding an alkali agent while mixing and stirring them, and furthermore, fly ash is added to the fly ash. 4. The method for treating fly ash according to claim 3, comprising a fourth step of adding an amount of zinc or more contained therein to an amount equivalent to or greater than zinc to form a hydroxide precipitate and a sulfide precipitate of heavy metals mainly containing zinc.
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005040437A1 (en) * | 2003-10-27 | 2005-05-06 | Dowa Mining Co., Ltd. | Method of wet treatment of fly ash |
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1998
- 1998-08-10 JP JP23661998A patent/JP3640288B2/en not_active Expired - Lifetime
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005040437A1 (en) * | 2003-10-27 | 2005-05-06 | Dowa Mining Co., Ltd. | Method of wet treatment of fly ash |
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