JP2003027272A - Method for electrochemically recovering heavy metal from fly ash - Google Patents
Method for electrochemically recovering heavy metal from fly ashInfo
- Publication number
- JP2003027272A JP2003027272A JP2001219251A JP2001219251A JP2003027272A JP 2003027272 A JP2003027272 A JP 2003027272A JP 2001219251 A JP2001219251 A JP 2001219251A JP 2001219251 A JP2001219251 A JP 2001219251A JP 2003027272 A JP2003027272 A JP 2003027272A
- Authority
- JP
- Japan
- Prior art keywords
- fly ash
- lead
- liquid
- zinc
- cadmium
- 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
Links
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
-
- 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
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/82—Recycling of waste of electrical or electronic equipment [WEEE]
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、廃棄物の再資源化
技術として焼却飛灰、溶融飛灰から金属類、とりわけ
銅、鉛、カドミウム、亜鉛等の有害な金属類を電気化学
的に回収する方法に関する。通常、廃自動車、廃家電製
品などはシュレッダーにより破砕して金属を回収する
が、その際残ったシュレッダーダストは焼却減容し、発
生する焼却飛灰あるいは焼却飛灰をさらにプラズマなど
で溶融処理する。本発明は、このようにシュレッダーダ
ストの焼却の際に発生する焼却飛灰、あるいはこの焼却
飛灰の溶融の際に発生する溶融飛灰から、各種金属を分
離回収する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is an electrochemical technique for recovering metals, particularly harmful metals such as copper, lead, cadmium and zinc, from incineration fly ash and molten fly ash as a technology for recycling waste. On how to do. Usually, scrapped automobiles, discarded home appliances, etc. are crushed by a shredder to recover metal, but the shredder dust remaining at that time is incinerated and reduced in volume, and the generated incinerated fly ash or incinerated fly ash is further melted by plasma etc. . The present invention relates to a method for separating and recovering various metals from incineration fly ash generated during incineration of shredder dust, or molten fly ash generated during melting of the incineration fly ash.
【０００２】[0002]
【従来の技術】ごみ焼却施設などから排出される飛灰中
には有害な金属類類が高濃度で含有されている。そのた
め、飛灰は厚生労働省の定めるつぎの４方法溶融法
セメント固化薬剤処理酸抽出のうちいずれかで中間
処理することが定められている。中間処理された飛灰は
最終処分地で埋め立て処分されるが、有害な金属類の除
去、浸出水中の塩類による悪影響、最終処分量の減容
化、あるいは金属類の再資源化の観点から、飛灰中の金
属類を回収する技術の確立が望まれている。例えば、湿
式処理によって金属を溶出し、次いで金属の種類ごとに
これを濃縮し、各金属を非鉄精錬用原料として使用でき
る程度の濃縮物として回収し、精錬する方法（特開平７
−１３８６３０号公報参照）などが提案されている。2. Description of the Related Art Fly ash discharged from a refuse incineration facility contains a high concentration of harmful metals. Therefore, it is stipulated that fly ash should be subjected to intermediate treatment by one of the following four methods defined by the Ministry of Health, Labor and Welfare, the melting method, cement solidification chemical treatment, and acid extraction. The fly ash after the intermediate treatment is landfilled at the final disposal site, but from the viewpoint of removing harmful metals, adverse effects of salts in leachate, reducing the volume of final disposal, or recycling metals, It is desired to establish a technology for recovering metals in fly ash. For example, a method of eluting a metal by a wet process, then concentrating the metal for each type of metal, recovering each metal as a concentrate enough to be used as a raw material for non-ferrous metal refining, and refining the metal (Japanese Patent Laid-Open No. HEI 7-18753).
No. 138630) is proposed.
【０００３】しかし、この方法では、金属溶出用の液に
高価な薬品を使用しなければならず、工程が複雑であ
り、加えて濃縮物が水酸化物や硫化物からなるスラッジ
であるため、容積が大きく、また有害物であることから
運搬面上多くの問題を抱えている。However, in this method, an expensive chemical must be used in the liquid for eluting the metal, the process is complicated, and the concentrate is sludge consisting of hydroxide or sulfide. Since it has a large volume and is a harmful substance, it has many problems in terms of transportation.
【０００４】[0004]
【発明が解決しようとする課題】本発明の課題は、シュ
レッダーダスト等の廃棄物を焼却した際に発生する焼却
飛灰、あるいは焼却飛灰をさらにプラズマなどで溶融し
た際に発生する溶融飛灰から、各種金属を効率よくかつ
簡単に分離回収することができる方法を提供することで
ある。An object of the present invention is to produce incinerated fly ash generated when incinerating waste such as shredder dust, or molten fly ash produced when the incinerated fly ash is further melted by plasma or the like. Therefore, it is to provide a method capable of efficiently and easily separating and recovering various metals.
【０００５】[0005]
【課題を解決するための手段】本発明は、飛灰をｐＨ４
以下の硫酸水溶液で抽出処理して同液に銅、カドミウム
および亜鉛を溶出させ、生じた飛灰含有スラリーの固液
分離により得られた分離液中で陽極と陰極の間で電気分
解を行い、陰極電位を徐々にまたは段階的に負の方向に
変化させることにより、陰極に銅、カドミウムおよび亜
鉛を分別して電解析出させ、その後、上記固液分離で残
った残渣を抽出薬液で抽出処理して同液に鉛を溶出さ
せ、生じた残渣含有スラリーの固液分離により得られた
分離液から鉛を電解析出させることを特徴とする飛灰か
らの重金属の電気化学的回収方法である。According to the present invention, fly ash is adjusted to pH 4
Copper, cadmium and zinc are eluted in the same solution by extraction with the following sulfuric acid aqueous solution, and electrolysis is performed between the anode and the cathode in the separated liquid obtained by solid-liquid separation of the resulting fly ash-containing slurry, By gradually or stepwise changing the cathode potential in the negative direction, copper, cadmium and zinc are separated and electrolytically deposited on the cathode, and then the residue remaining in the solid-liquid separation is extracted with an extraction chemical solution. Is a method for electrochemically recovering heavy metals from fly ash, characterized in that lead is eluted in the same liquid, and lead is electrolytically deposited from a separated liquid obtained by solid-liquid separation of the resulting residue-containing slurry.
【０００６】本発明者らは、飛灰中の金属類の分離回収
を行うために鋭意研究を進めた結果、先に、各種飛灰中
の重金属を塩酸酸性水溶液などで溶出した後、各種金属
の電気化学的析出電位に差異がある点を利用し、陰極電
位を貴な電位から卑な電位へ徐々にまたは段階的に変化
させ、銅、鉛、カドミウム、亜鉛等の重金属を金属イン
ゴットの形態で析出させることが可能であることを知見
した（特願２０００−３７０８７７号明細書）。また、
その改良発明として、ｐＨ１以上の水溶液で飛灰中の
銅、カドミウム、亜鉛などの重金属を抽出した後に、各
種金属の電気化学的析出電位に差異がある点を利用し、
陰極電位を貴な電位から卑な電位へ段階的に移行させ、
銅、カドミウムおよび亜鉛を電解析出させた後、ｐＨを
１以下にして鉛を抽出し、抽出液の電気分解で鉛を析出
させる方法を見出した（特願２００１−００３３８４号
明細書）。さらに、その改良発明として、飛灰からｐＨ
１２以上の水溶液で鉛と亜鉛を抽出した後に、各種金属
の電気化学的析出電位に差異がある点を利用し、陰極電
位を貴な電位から卑な電位へ段階的に移行させ、鉛、亜
鉛を電解析出させた後、ｐＨ１２以上で抽出できなかっ
た銅、カドミウムを含む残渣をｐＨ１〜５にして銅、カ
ドミウムを抽出させ、貴な電位から卑な電位へ電位を段
階的に移行させ、銅、カドミウムを電解析出させる方法
を見出した（特願２００１−０３７８１９号明細書）。The present inventors have conducted extensive research to separate and recover metals in fly ash. As a result, the heavy metals in various fly ash were first eluted with hydrochloric acid acidic aqueous solution and then various metals were extracted. By utilizing the difference in the electrochemical deposition potential of, the cathode potential is gradually or gradually changed from a noble potential to a base potential, and heavy metals such as copper, lead, cadmium, and zinc are formed into a metal ingot. It has been found that it is possible to precipitate it by (Japanese Patent Application No. 2000-370877). Also,
As an improved invention, utilizing the fact that after extracting heavy metals such as copper, cadmium, and zinc in fly ash with an aqueous solution of pH 1 or more, there is a difference in the electrochemical deposition potential of various metals,
The cathode potential is gradually shifted from the noble potential to the base potential,
We have found a method of electrolytically depositing copper, cadmium and zinc, then adjusting the pH to 1 or less to extract lead, and electrolyzing the extract to deposit lead (Japanese Patent Application No. 2001-003384). Furthermore, as an improved invention, the pH from fly ash
After extracting lead and zinc with an aqueous solution of 12 or more, utilizing the fact that there are differences in the electrochemical deposition potentials of various metals, the cathode potential is gradually shifted from a noble potential to a base potential, and lead and zinc are extracted. After electrolytically depositing, the residue containing copper and cadmium that could not be extracted at pH 12 or higher was adjusted to pH 1 to 5 to extract copper and cadmium, and the potential was gradually transferred from the noble potential to the base potential, A method for electrolytically depositing copper and cadmium was found (Japanese Patent Application No. 2001-037819).
【０００７】ここで、飛灰中の重金属の内で廃棄規制の
観点から重要なものは、鉛と亜鉛の回収であり、これら
を分別して回収することが重要である。Here, among the heavy metals in the fly ash, the important one from the viewpoint of waste regulation is the recovery of lead and zinc, and it is important to separate and recover them.
【０００８】一番目と二番目の発明では、いずれも酸性
水溶液で抽出を行うが、薬剤として硫酸を使用すると不
溶性の硫酸鉛が析出するため、これを以後の電解析出へ
供することができない。従ってこの場合には必然的に塩
酸あるいは硝酸を使用することになるが、この場合は抽
出液を電解すると有害な塩素ガスや、亜硝酸ガスが発生
する問題が生ずる。また、三番目の発明では、ｐＨ１２
以上の水溶液で抽出をする場合に、苛性ソーダなどの薬
剤がアルミニウムや鉄の抽出のためにも多量に消費され
てしまいコスト高を招く上に、抽出した鉛と亜鉛を電解
する場合に、陰極電圧を制御しても一部は鉛と亜鉛の合
金として電解析出し、析出物の資源価値が落ちるという
問題があった。In both the first and second inventions, the extraction is carried out with an acidic aqueous solution. However, when sulfuric acid is used as a chemical, insoluble lead sulfate is deposited, so that it cannot be subjected to subsequent electrolytic deposition. Therefore, in this case, hydrochloric acid or nitric acid is inevitably used, but in this case, when the extract is electrolyzed, harmful chlorine gas or nitrous acid gas is generated. Further, in the third invention, pH12
When extracting with the above aqueous solution, chemicals such as caustic soda are consumed in large amounts for the extraction of aluminum and iron, leading to high costs, and when electrolyzing the extracted lead and zinc, the cathode voltage However, there is a problem that a part of the alloy is electrolytically deposited as an alloy of lead and zinc and the resource value of the deposit is reduced.
【０００９】本発明においては、飛灰抽出処理用の酸と
してｐＨ４以下の硫酸水溶液を使用するので、抽出液に
は鉛が含まれず、電解析出した亜鉛は鉛を含まない。ま
た、電解を硫酸水溶液で行うので、電解中には有害な塩
素ガスや亜硝酸ガスが発生しない。さらに、硫酸抽出後
の残渣にはＰｂＳＯ４、ＣａＳＯ４、アルミナ、シリカ
しか残っていないので、鉛を抽出する場合の薬剤使用量
が少なくてすむ。In the present invention, since an aqueous sulfuric acid solution having a pH of 4 or less is used as the acid for the fly ash extraction treatment, the extract does not contain lead, and the electrolytically deposited zinc does not contain lead. Further, since the electrolysis is carried out with a sulfuric acid aqueous solution, no harmful chlorine gas or nitrous acid gas is generated during the electrolysis. Furthermore, since only PbSO 4 , CaSO 4 , alumina, and silica remain in the residue after extraction with sulfuric acid, the amount of chemicals used for extracting lead can be small.
【００１０】電解析出反応が進行するにつれて水溶液中
の金属イオンの濃度が薄くなり、析出に関する電流効率
が低下するので、電解析出により溶液中の金属イオン濃
度を減少させる際の目安を１０−４〜１０−２ｍｏｌ／
ｌ程度に置き、あまり低い濃度まで反応を行わないで、
低濃度の金属イオンを含有する水溶液を循環再利用す
る。本方法によると、析出に関する電流効率を下げずに
効率よく電解析出を行うことができる。As the electrolytic deposition reaction proceeds, the concentration of metal ions in the aqueous solution decreases, and the current efficiency for deposition decreases. Therefore, a guideline for reducing the concentration of metal ions in a solution by electrolytic deposition is 10 −. 4 to 10 -2 mol /
Place it at about 1 l and do not react to a too low concentration,
An aqueous solution containing a low concentration of metal ions is circulated and reused. According to this method, electrolytic deposition can be performed efficiently without lowering the current efficiency for deposition.
【００１１】[0011]
【発明の実施の形態】第１工程で、抽出槽で飛灰を水の
添加によりスラリーとし、このスラリーを攪拌しながら
硫酸水溶液を添加してｐＨを４以下にする。ここで、硫
酸の添加でｐＨを４以下にするのは、銅、カドミウムお
よび亜鉛を溶解させるが、鉛は溶解させないためであ
る。上記ｐＨを維持しての攪拌時間は、３０分以上であ
ればよく、温度は室温でもよいが溶解速度を促進するた
めには５０℃以上にするのが望ましい。次いで、上記ス
ラリーを濾過槽やフィルタープレスなどの濾過装置で濾
過して固液分離する。BEST MODE FOR CARRYING OUT THE INVENTION In the first step, fly ash is made into a slurry by adding water in an extraction tank, and an aqueous sulfuric acid solution is added to the slurry while stirring the slurry to adjust the pH to 4 or less. Here, the reason why the pH is adjusted to 4 or less by adding sulfuric acid is that copper, cadmium and zinc are dissolved but lead is not dissolved. The stirring time while maintaining the above pH may be 30 minutes or longer, and the temperature may be room temperature, but it is preferably 50 ° C. or higher in order to accelerate the dissolution rate. Next, the slurry is filtered with a filtering device such as a filter tank or a filter press to perform solid-liquid separation.
【００１２】第２工程では、濾液を陽極と陰極との間で
電気分解により銅、カドミウムおよび亜鉛を析出させ
る。ここで、陽極としては、チタンあるいは白金めっき
したチタンからなる電極を使用し、陰極としては、銅の
電解析出時には銅電極を、カドミウムの電解析出時には
アルミニウム電極を、亜鉛の電解析出時にはチタン電極
を使用する。さらに、電解析出により溶液中の金属イオ
ン濃度を減少させる際の目安を１０−４〜１０−２ｍｏ
ｌ／ｌ程度に置き、あまり低い濃度まで反応させないよ
うにする。なぜなら、溶液中の金属イオン濃度が１０
−４ｍｏｌ／ｌ以下になると、電流効率が２０％以下と
小さくなるからである。In the second step, copper, cadmium and zinc are deposited on the filtrate by electrolysis between the anode and the cathode. Here, as the anode, an electrode made of titanium or platinum-plated titanium is used, and as the cathode, a copper electrode is used for electrolytic deposition of copper, an aluminum electrode is used for electrolytic deposition of cadmium, and an electrolytic electrode of zinc is used for electrolytic deposition of zinc. Use titanium electrodes. Furthermore, a guideline for reducing the metal ion concentration in the solution by electrolytic deposition is 10 −4 to 10 −2 mo.
Place it at about 1 / l so that it does not react to a too low concentration. Because the metal ion concentration in the solution is 10
This is because if it is -4 mol / l or less, the current efficiency is reduced to 20% or less.
【００１３】第３工程では、第１工程で固液分離した後
の残査から、苛性ソーダ、炭酸ソーダおよび／またはチ
オ硫酸ソーダを含む液を用いて鉛を抽出する。In the third step, lead is extracted from the residue obtained after the solid-liquid separation in the first step, using a solution containing caustic soda, sodium carbonate and / or sodium thiosulfate.
【００１４】第４工程では、第３工程で抽出した溶液か
ら鉛を電解析出するが、陽極にはチタンあるいは白金め
っきしたチタンからなる電極を使用し、陰極には鉛ある
いはチタンからなる電極を使用するのが望ましい。In the fourth step, lead is electrolytically deposited from the solution extracted in the third step. An electrode made of titanium or platinum-plated titanium is used for the anode, and an electrode made of lead or titanium is used for the cathode. It is desirable to use.
【００１５】第５工程では、第２工程により銅、カドミ
ウムおよび亜鉛の回収を終えた後の、これらの金属イオ
ン濃度が１０−４ｍｏｌ／ｌ以下になった液を第１工程
の飛灰の抽出に、第４工程により鉛の回収を終えた後
の、鉛イオン濃度が１０−４ｍｏｌ／ｌ以下になった液
を第３工程の残渣の抽出にそれぞれ循環再使用して、新
たな飛灰に対し、第１〜第４工程を行う。なお、このよ
うな操作を繰り返し行うと、アルミニウム、カリウム、
ナトリウムなどは次第に濃縮してこれら自身の溶解度ま
で達して、第４工程において自然に溶解しなくなる。ま
た、鉄、クロムはカドミウムめっき時に合金鍍金として
析出する。In the fifth step, after the recovery of copper, cadmium and zinc in the second step is completed, the liquid having a metal ion concentration of 10 -4 mol / l or less is used as a fly ash in the first step. For the extraction, after the lead recovery was completed in the fourth step, the liquid having a lead ion concentration of 10 −4 mol / l or less was circulated and reused in the extraction of the residue in the third step, and a new fly was used. The first to fourth steps are performed on the ash. If such an operation is repeated, aluminum, potassium,
Sodium and the like are gradually concentrated and reach the solubility of themselves, so that they do not spontaneously dissolve in the fourth step. Further, iron and chromium are deposited as alloy plating during cadmium plating.
【００１６】つぎに、本発明を実施例に基づいて具体的
に説明する。Next, the present invention will be specifically described based on examples.
【００１７】実施例
（第１工程）まず、５００ｍｌビーカーに溶融飛灰２０
ｇを入れ、その中に１Ｎ硫酸水溶液を２００ｍｌ入れて
全体を５０℃で１時間攪拌し、生じたスラリーを固液分
離した。得られた分離液のｐＨは１．２であった。Example (First Step) First, molten fly ash 20 was placed in a 500 ml beaker.
g was added, 200 ml of a 1N sulfuric acid aqueous solution was added, and the whole was stirred at 50 ° C. for 1 hour, and the resulting slurry was subjected to solid-liquid separation. The pH of the obtained separated liquid was 1.2.
【００１８】（第２工程）その後、分離液中に、陽極と
して面積５０ｃｍ２ の白金めっきしたチタン電極を、
陰極として面積５０ｃｍ２ の銅板を入れて、２．５Ａ
の一定電流で電解を行った。その時、陰極電位は−０．
２３Ｖ（ｖｓ．標準水素電位）から−０．３０Ｖ（ｖ
ｓ．標準水素電位）まで徐々に低下し、銅の濃度は表１
に示すように０．１７（ｇ／ｌ）から０．０１２（ｇ／
ｌ）まで減少した。(Second step) After that, a platinum electrode having a surface area of 50 cm 2 and being plated with platinum was used as an anode in the separated liquid.
Put a copper plate with an area of 50 cm 2 as a cathode, and
Electrolysis was carried out at a constant current. At that time, the cathode potential was −0.
23 V (vs. standard hydrogen potential) to -0.30 V (v
s. The standard hydrogen potential) gradually decreases, and the copper concentration is shown in Table 1.
As shown in 0.17 (g / l) to 0.012 (g / l)
l).
【００１９】その後、陰極を面積５０ｃｍ２ のチタン
電極に変えて同じく２．５Ａの一定電流で電解を行っ
た。その時、陰極電位は−１．２９Ｖ（ｖｓ．標準水素
電位）から−１．３８Ｖ（ｖｓ．標準水素電位）まで徐
々に低下し、亜鉛の濃度は表１に示すように３．４５
（ｇ／ｌ）から０．０４８（ｇ／ｌ）まで減少した。Then, the cathode was changed to a titanium electrode having an area of 50 cm 2 and electrolysis was carried out at a constant current of 2.5 A. At that time, the cathode potential gradually decreased from −1.29 V (vs. standard hydrogen potential) to −1.38 V (vs. standard hydrogen potential), and the zinc concentration was 3.45 V as shown in Table 1.
(G / l) to 0.048 (g / l).
【００２０】（第３工程）第１工程で固液分離した後の
固体残渣７．８ｇを５００ｍｌのビーカーに入れ、その
中に、１Ｎ苛性ソーダ水溶液を１７０ｍｌ入れて５０℃
で１時間攪拌し、生じたスラリーを固液分離した。得ら
れた分離液のｐＨは１２．８であった。(Third step) 7.8 g of the solid residue after solid-liquid separation in the first step was put into a 500 ml beaker, 170 ml of 1N caustic soda aqueous solution was put therein, and 50 ° C.
The resulting slurry was solid-liquid separated. The pH of the obtained separated liquid was 12.8.
【００２１】（第４工程）第３工程で得た分離液中に、
陽極として面積５０ｃｍ２ の白金めっきしたチタン電
極を、陰極として面積５０ｃｍ２ の銅板を入れて、
２．５Ａの一定電流で電解を行った。その時、陰極電位
は−０．９２Ｖ（ｖｓ．標準水素電位）から−１．２９
Ｖ（ｖｓ．標準水素電位）まで徐々に低下し、鉛の濃度
は表１に示すように１．４８（ｇ／ｌ）から０．２１
（ｇ／ｌ）まで減少した。(Fourth step) In the separated liquid obtained in the third step,
The platinum plated titanium electrode with an area of 50 cm 2 as the anode, put the copper plate of area 50 cm 2 as the cathode,
Electrolysis was performed at a constant current of 2.5A. At that time, the cathode potential was −0.92 V (vs. standard hydrogen potential) to −1.29.
V (vs. standard hydrogen potential) gradually decreased, and the lead concentration was 1.48 (g / l) to 0.21 as shown in Table 1.
(G / l).
【００２２】（第５工程）第２工程により銅、カドミウ
ムおよび亜鉛の回収を終えた後の、これらの金属イオン
濃度が１０−４ｍｏｌ／ｌ以下になった液を第１工程の
飛灰の抽出に、第４工程により鉛の回収を終えた後の、
鉛イオン濃度が１０−４ｍｏｌ／ｌ以下になった液を第
３工程の残渣の抽出にそれぞれ循環再使用して、新たな
飛灰に対し、第１〜第４工程を行った。その場合、２回
目溶出液、２回目電解後液も１回目と同様に溶出および
電解ができた。このような操作を繰り返し行ったとこ
ろ、５回目以降では、溶出液中のカドミウム濃度が高く
なり、カドミウムの電解が可能となったので、銅の電解
時に−０．４２Ｖ（ｖｓ．標準水素電位）になった時点
で陰極を面積５０ｃｍ２ のアルミニウム板に変更して
−１．０３Ｖ（ｖｓ．標準水素電位）になるまで２．５
Ａの電流で電解を行った。各溶出操作時の収率は９０％
以上、電解操作時の効率は６０％以上であり、飛灰から
効率的に重金属を回収できることが明らかになった。(Fifth Step) After the completion of the recovery of copper, cadmium and zinc by the second step, the liquid containing these metal ions at a concentration of 10 −4 mol / l or less is used as a fly ash in the first step. After extraction of lead in the fourth step,
The liquids having a lead ion concentration of 10 −4 mol / l or less were circulated and reused for extraction of the residue in the third step, and the first to fourth steps were performed on the new fly ash. In that case, the second eluate and the second post-electrolysis solution could be eluted and electrolyzed in the same manner as the first. When such an operation was repeated, the cadmium concentration in the eluate increased after the fifth time, and the electrolysis of cadmium became possible. Therefore, during the electrolysis of copper, -0.42 V (vs. standard hydrogen potential) was obtained. At that point, the cathode was changed to an aluminum plate having an area of 50 cm 2 and 2.5 was applied until it became −1.03 V (vs. standard hydrogen potential).
Electrolysis was performed at the current of A. 90% yield in each elution operation
As described above, the efficiency during the electrolysis operation was 60% or more, and it was revealed that heavy metals can be efficiently recovered from fly ash.
【００２３】[0023]
【表１】 [Table 1]
【００２４】[0024]
【発明の効果】本発明の方法によれば、飛灰から銅、カ
ドミウム、亜鉛、鉛等の重金属を効率的に回収すること
ができる。According to the method of the present invention, heavy metals such as copper, cadmium, zinc and lead can be efficiently recovered from fly ash.
【図１】実施例による飛灰からの重金属回収方法を示す
フローシートである。FIG. 1 is a flow sheet showing a method for recovering heavy metals from fly ash according to an embodiment.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｃ２２Ｂ 7/02 Ｃ２５Ｃ 1/16 Ａ 13/00 Ｂ 15/00 1/18 17/00 7/02 ３０６ 19/30 Ｂ０９Ｂ 3/00 ３０４Ｇ Ｃ２５Ｃ 1/12 ＺＡＢ 1/16 Ｃ２２Ｂ 3/00 Ａ 15/08 1/18 17/04 7/02 ３０６ 13/04 (72)発明者 近藤 雅芳 大阪市住之江区南港北１丁目７番89号 日 立造船株式会社内 (72)発明者 辰己 浩史 大阪市住之江区南港北１丁目７番89号 日 立造船株式会社内 Ｆターム(参考） 4D004 AA37 AB03 BA05 CA40 CA44 CC12 DA03 DA20 4D056 AB03 AB04 AB08 AC21 AC22 DA10 4K001 AA06 AA09 AA20 AA30 BA22 DB03 4K058 AA21 BA21 BA24 BA25 BA27 BB04 CA04 CA07 CA13 CA20 EB13 EB15 EB16 FB03 FB08 FC07 FC14 FC15 ─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. 7 Identification Code FI Theme Coat (Reference) C22B 7/02 C25C 1/16 A 13/00 B 15/00 1/18 17/00 7/02 306 19 / 30 B09B 3/00 304G C25C 1/12 ZAB 1/16 C22B 3/00 A 15/08 1/18 17/04 7/02 306 13/04 (72) Inventor Masayoshi Kondo 1 Minami Kohoku, Suminoe-ku, Osaka 7-89, Nitate Shipbuilding Co., Ltd. (72) Inventor Hiroshi Tatsumi 1-89, Minami Kohoku, Suminoe-ku, Osaka City F-Term (Reference) 4-9 4D056 AB03 AB04 AB08 AC21 AC22 DA10 4K001 AA06 AA09 AA20 AA30 BA22 DB03 4K058 AA21 BA21 BA24 BA25 BA27 BB04 CA04 CA07 CA13 CA20 EB13 EB15 EB16 FB03 FB08 FC07 FC14 FC15
Claims (4)
理して同液に銅、カドミウムおよび亜鉛を溶出させ、生
じた飛灰含有スラリーの固液分離により得られた分離液
中で陽極と陰極の間で電気分解を行い、陰極電位を徐々
にまたは段階的に負の方向に変化させることにより、陰
極に銅、カドミウムおよび亜鉛を分別して電解析出さ
せ、その後、上記固液分離で残った残渣を抽出薬液で抽
出処理して同液に鉛を溶出させ、生じた残渣含有スラリ
ーの固液分離により得られた分離液から鉛を電解析出さ
せることを特徴とする飛灰からの重金属の電気化学的回
収方法。1. A fly ash is subjected to extraction treatment with a sulfuric acid aqueous solution having a pH of 4 or less to elute copper, cadmium and zinc in the same solution, and an anode is used in a separation liquid obtained by solid-liquid separation of the resulting fly ash-containing slurry. By performing electrolysis between the cathodes and gradually or gradually changing the cathode potential in the negative direction, copper, cadmium and zinc are separated and electrolytically deposited on the cathodes, and then the solid-liquid separation is performed. Heavy metal from fly ash, characterized in that the residue is extracted with an extract chemical to elute lead in the same, and lead is electrolytically deposited from the separated liquid obtained by solid-liquid separation of the resulting residue-containing slurry. Electrochemical recovery method of.
ムおよび亜鉛の回収を終えた後の液を飛灰の抽出に、鉛
の回収を終えた後の液を残渣の抽出にそれぞれ循環再使
用して、新たな飛灰に対し請求項１記載の方法に従って
金属抽出および電解析出を行うことを特徴とする飛灰か
らの重金属の電気化学的回収方法。2. The liquid after recovery of copper, cadmium and zinc by the method according to claim 1 is recycled for extraction of fly ash, and the liquid after recovery of lead is recycled for extraction of residues, respectively. Then, a method for electrochemically recovering heavy metals from fly ash, which comprises subjecting new fly ash to metal extraction and electrolytic deposition according to the method of claim 1.
ダ、炭酸ソーダおよび／またはチオ硫酸ソーダを含む液
を用いることを特徴とする請求項１記載の飛灰からの重
金属の電気化学的回収方法。3. The method for electrochemically recovering heavy metals from fly ash according to claim 1, wherein a liquid containing caustic soda, sodium carbonate and / or sodium thiosulfate is used as an extracting chemical liquid for extracting lead.
陽極にチタンあるいは白金めっきしたチタンからなる電
極を、陰極に、銅の電解析出時には銅電極を、カドミウ
ムの電解析出時にはアルミニウム電極を、亜鉛の電解析
出時にはチタン電極を、鉛の電解析出時には鉛電極また
はチタン電極を順番に取り替えて用いることを特徴とす
る飛灰からの重金属の電気化学的回収方法。4. The invention according to claim 1 or 2,
An electrode made of titanium or platinum-plated titanium for the anode, a cathode for the electrolytic deposition of copper, an aluminum electrode for the electrolytic deposition of cadmium, a titanium electrode for the electrolytic deposition of zinc, and an electrical analysis for lead. A method for electrochemically recovering heavy metals from fly ash, characterized in that the lead electrode or the titanium electrode is sequentially replaced at the time of release.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001219251A JP2003027272A (en) | 2001-07-19 | 2001-07-19 | Method for electrochemically recovering heavy metal from fly ash |
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|---|---|
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ID=19053285
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120234137A1 (en) * | 2009-10-06 | 2012-09-20 | Elemetal Holding B.V. | Hydrometalurgical process and apparatus for recovering metals from waste material |
| WO2021021786A1 (en) * | 2019-08-01 | 2021-02-04 | Aqua Metals Inc. | Metal recovery from lead containing electrolytes |
-
2001
- 2001-07-19 JP JP2001219251A patent/JP2003027272A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120234137A1 (en) * | 2009-10-06 | 2012-09-20 | Elemetal Holding B.V. | Hydrometalurgical process and apparatus for recovering metals from waste material |
| US9023129B2 (en) * | 2009-10-06 | 2015-05-05 | Elemetal Holding B.V. | Hydrometalurgical process and apparatus for recovering metals from waste material |
| WO2021021786A1 (en) * | 2019-08-01 | 2021-02-04 | Aqua Metals Inc. | Metal recovery from lead containing electrolytes |
| CN114341403A (en) * | 2019-08-01 | 2022-04-12 | 艾库伊金属有限公司 | Recovery of metals from lead-containing electrolytes |
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