JP2002205030A - Method of electrochemically recovering heavy metals from fly ash - Google Patents
Method of electrochemically recovering heavy metals from fly ashInfo
- Publication number
- JP2002205030A JP2002205030A JP2001003384A JP2001003384A JP2002205030A JP 2002205030 A JP2002205030 A JP 2002205030A JP 2001003384 A JP2001003384 A JP 2001003384A JP 2001003384 A JP2001003384 A JP 2001003384A JP 2002205030 A JP2002205030 A JP 2002205030A
- Authority
- JP
- Japan
- Prior art keywords
- fly ash
- lead
- zinc
- copper
- slurry
- 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
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
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 The present invention relates to a technology for recycling waste materials by electrochemically recovering harmful metals such as copper, lead, cadmium and zinc from incinerated fly ash and molten fly ash. On how to do it. Normally, scrap automobiles and household electrical appliances are shredded by a shredder to recover metal, but the remaining shredder dust is incinerated and reduced in volume. . The present invention relates to a method for separating and recovering various metals from incinerated fly ash generated when shredder dust is incinerated, or from molten fly ash generated when the incinerated fly ash is melted.
【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７−１３
８６３０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 waste incineration facilities and the like contains high concentrations of harmful metals. Therefore, fly ash is stipulated to be subjected to intermediate treatment by one of the following four-method molten cement cement solidification chemical treatment acid extraction specified by the Ministry of Health and Welfare. Fly ash that has undergone intermediate treatment is landfilled at the final disposal site, but removal of harmful metals,
From the viewpoints of adverse effects of salts in leachate, reduction of final disposal volume, and recycling of metals, establishment of a technique for recovering metals in fly ash is desired. For example, a method in which a metal is eluted by wet treatment, and then concentrated for each type of metal, and each metal is recovered as a concentrate that can be used as a raw material for non-ferrous refining, and is refined (JP-A-7-13)
No. 8630) has been 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 as a metal eluting solution, and the process is complicated. In addition, the concentrate is a sludge composed of hydroxide or sulfide. Due to its large volume and harmfulness, 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。SUMMARY OF THE INVENTION An object of the present invention is to provide incineration fly ash generated when incinerating waste such as shredder dust, or molten fly ash generated when incineration fly ash is further melted by plasma or the like. Therefore, it is an object of the present invention to provide a method capable of efficiently and easily separating and collecting various metals.
【０００５】[0005]
【課題を解決するための手段】本発明者らは、先に、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、各種飛灰中の重金属を塩酸酸性水溶液などで溶解
抽出後、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２０００−３７０８７
７）。Means for Solving the Problems The inventors of the present invention have conducted intensive studies to separate and recover metals in fly ash, and as a result, heavy metals in various fly ash have been removed with an aqueous hydrochloric acid solution or the like. After the dissolution extraction, utilizing the point that the electrochemical deposition potential of various metals is different, the cathode potential is gradually or stepwise changed from a noble potential to a noble potential, such as copper, lead, cadmium, zinc, etc. It has been found that heavy metals can be precipitated in the form of metal ingots (Japanese Patent Application No. 2000-37087).
7).
【０００６】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銅、鉛、カドミウム、亜鉛であ
る。この内、銅、カドミウム、亜鉛はｐＨ１以上の酸性
領域で十分に抽出できるが、鉛に関してはＰｂＣｌ２
やＰｂＳＯ４ の溶解度が小さいために、ｐＨを１以下
にして、Ｈ２ ＰｂＣｌ４ やＰｂ（ＨＳＯ４ ）＋と
いう溶解度の高い錯体を生成させないと、鉛は抽出でき
ない。従って、抽出工程を１段にするためには、ｐＨを
１以下にする必要があり、この場合、銅、カドミウム、
亜鉛の電解析出工程において析出に関する電流効率が低
くなる欠点があった。また、鉛の電解析出時に銅イオン
が一定のモル比率（Ｃｕ＋＋／Ｐｂ＋＋＝０．５）以上
で存在すると、鉛の電解析出が起こらないという問題も
あった。Here, of the heavy metals in the fly ash, those important from the viewpoint of disposal regulations are copper, lead, cadmium and zinc. Among these, copper, cadmium, and zinc can be extracted well with pH1 more acidic region, for lead PbCl 2
And for the solubility of PbSO 4 is small, pH was 1 or less, and the H 2 PbCl 4 and Pb (HSO 4) does not form a complex having high solubility as +, lead can not be extracted. Therefore, in order to make the extraction process one stage, the pH needs to be 1 or less. In this case, copper, cadmium,
There was a disadvantage that the current efficiency related to the deposition was lowered in the zinc electrolytic deposition step. In addition, when copper ions are present in a certain molar ratio (Cu ++ / Pb ++ = 0.5) or more during the electrolytic deposition of lead, there is another problem that the electrolytic deposition of lead does not occur.
【０００７】本発明は、この点に鑑み、抽出工程を２段
にして、１回目の抽出（ｐＨ１以上）において銅、カド
ミウム、亜鉛を抽出し、２回目の抽出（ｐＨ１以下）に
おいて鉛を抽出することからなる、飛灰からの重金属の
電気化学的回収方法を提供する。In view of this point, the present invention provides a two-stage extraction process in which copper, cadmium and zinc are extracted in the first extraction (pH 1 or more) and lead is extracted in the second extraction (pH 1 or less). Providing a method for electrochemically recovering heavy metals from fly ash.
【０００８】すなわち、請求項１記載の発明は、飛灰の
スラリーをｐＨ１以上に調整して飛灰から銅、カドミウ
ム、亜鉛等の重金属を抽出し、該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、銅、カドミウム、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固体残渣のス
ラリーをｐＨ１以下に調整して鉛を抽出し、該スラリー
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電気化学的重金属の回収方法であ
る。That is, according to the first aspect of the present invention, a fly ash slurry is adjusted to a pH of 1 or more to extract heavy metals such as copper, cadmium and zinc from the fly ash, and the separation obtained by solid-liquid separation of the slurry is obtained. Electrolysis is performed between the anode and the cathode in the liquid, and by gradually or stepwise changing the cathode potential in the negative direction, copper, cadmium, and zinc are separated and electrolytically deposited. A slurry of a solid residue remaining after the separation is adjusted to a pH of 1 or less to extract lead, and electrolytically depositing lead from a separated liquid obtained by solid-liquid separation of the slurry. Is the way.
【０００９】また、このような電解析出を行うと、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くなる欠点がある。こ
の問題を解決するために、本発明では、電解析出により
溶融中の金属イオン濃度が下がる際の目安として、１０
−４〜１０−２mol ／l 程度に置き、あまり低い濃度ま
で反応をさせないで、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。In addition, when such electrolytic deposition is performed, the concentration of metal ions in the aqueous solution decreases as the reaction proceeds, and there is a disadvantage that the current efficiency relating to the deposition decreases. In order to solve this problem, according to the present invention, as a guide when the metal ion concentration during melting is lowered by electrolytic deposition, 10
An aqueous solution containing a low concentration of metal ions is circulated and reused without allowing the reaction to proceed to a very low concentration, by placing the solution at about -4 to 10 -2 mol / l. According to this method, the electrolytic deposition can be performed efficiently without lowering the current efficiency relating to the deposition.
【００１０】すなわち、請求項２記載の発明は、請求項
１記載の方法により鉛の回収を終えた後の液を用いて、
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電気化学的重金
属の回収方法である。That is, the invention according to claim 2 uses the liquid after the lead has been recovered by the method according to claim 1,
A method for recovering electrochemical heavy metals, wherein metal extraction and electrolytic deposition are performed on fresh fly ash according to the method of claim 1.
【００１１】請求項３記載の発明は、請求項１または２
記載の発明において、陽極に、酸化イリジウム被覆した
チタン上に二酸化マンガンと酸化モリブデンを析出させ
た電極または白金メッキしたチタン電極を使用し、陰極
には、銅の電解析出時には銅を、鉛の電解析出時には鉛
あるいは鉛めっきした鋼板を、カドミウムの電解析出時
にはアルミニウムを、亜鉛の電解析出時にはアルミニウ
ム、亜鉛あるいは亜鉛めっき鋼板を順番に取り替えて使
用することを特徴とする電気化学的重金属の回収方法で
ある。[0011] The invention according to claim 3 is the invention according to claim 1 or 2.
In the described invention, an anode, an electrode obtained by depositing manganese dioxide and molybdenum oxide on iridium oxide-coated titanium or a platinum-plated titanium electrode is used. Electrochemical heavy metals characterized by replacing lead or lead-plated steel sheets during electrolytic deposition, replacing aluminum during cadmium electrolytic deposition, and replacing aluminum, zinc or galvanized steel sheets during zinc electrolytic deposition. It is a method of collecting.
【００１２】[0012]
【発明の実施の形態】まず、第１工程では、飛灰を水に
投入してスラリーとし、このスラリーを攪拌しながら塩
酸、硝酸、硫酸などの鉱酸を添加してｐＨを１〜５に調
整する。ここで、ｐＨを１以上にするのは、Ｈ２ Ｐｂ
Ｃｌ４ やＰｂ（ＨＳＯ４ ）＋ という溶解度の高い
錯体が生成して液中に鉛が溶解するのを防止するためで
ある。また、ｐＨを５以下にするのは、ｐＨが５以上で
あると銅、カドミウム、亜鉛を十分に抽出できないため
である。上記ｐＨを維持しての攪拌時間は３０分以上で
あればよい。スラリーの温度は室温でもよいが上記錯体
の生成速度を促進するために、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
レスなどの分離装置で固液分離する。DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first step, fly ash is charged into water to form a slurry, and a mineral acid such as hydrochloric acid, nitric acid, sulfuric acid or the like is added to the slurry while stirring to adjust the pH to 1 to 5. adjust. Here, the reason for setting the pH to 1 or more is that H 2 Pb
This is to prevent the formation of a highly soluble complex of Cl 4 or Pb (HSO 4 ) + to dissolve lead in the liquid. The reason why the pH is set to 5 or less is that when the pH is 5 or more, copper, cadmium and zinc cannot be sufficiently extracted. The stirring time while maintaining the above pH may be 30 minutes or more. The temperature of the slurry may be room temperature, but is desirably 50 ° C. or higher in order to accelerate the formation rate of the complex. Next, the slurry is subjected to solid-liquid separation using a separation device such as a filtration tank or a filter press.
【００１３】つぎに、第２工程では、濾液中に設けられ
た陽極と陰極との間で電気分解を行って、銅、カドミウ
ム、亜鉛等の重金属を析出させるにあたり、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、銅、カドミウム、亜鉛を分別して析出させる。Next, in the second step, the electrolysis is carried out between an anode and a cathode provided in the filtrate to deposit heavy metals such as copper, cadmium and zinc. By changing it in the negative direction, copper, cadmium and zinc are separated and deposited.
【００１４】陽極としては、環境面から塩素が発生しな
いように考慮して、藤村らが製作した酸化イリジウム被
覆したチタン板上に二酸化マンガンと酸化モリブデンを
析出させた電極（Electrochimica Acta 45, （2000）22
97-2303 ）を使用するのが好ましい。また、経済性を考
慮して、白金メッキしたチタン電極を陽極に使用するこ
ともできる。この場合、発生した塩素を水酸化ナトリウ
ム溶液に吸収させ、次亜塩素酸ナトリウムを生成させる
のが好ましい。チタンに白金メッキを施す理由は、チタ
ンをメッキなしで用いると、その表面が酸化されて酸化
チタンとなり、電解電圧が上昇し、電解電力コストが高
くなるからである。As an anode, an electrode prepared by depositing manganese dioxide and molybdenum oxide on an iridium oxide-coated titanium plate manufactured by Fujimura et al. (Electrochimica Acta 45, (2000) )twenty two
97-2303) is preferred. Also, in consideration of economic efficiency, a platinum-plated titanium electrode can be used for the anode. In this case, it is preferable that the generated chlorine is absorbed in a sodium hydroxide solution to generate sodium hypochlorite. The reason for applying platinum plating to titanium is that if titanium is used without plating, its surface is oxidized to titanium oxide, the electrolytic voltage increases, and the electrolytic power cost increases.
【００１５】陰極としては、回収金属種と電流効率を考
慮して、銅の析出時には銅板を、カドミウムの析出時に
アルミニウム板を、亜鉛の析出時にはアルミニウム板、
亜鉛板あるいは亜鉛めっきした鋼板を使用するのが望ま
しい。また、電流密度は０．１Ａ／ｃｍ２ 以下である
のが好ましい。なぜなら、使用した酸化イリジウム被覆
チタン板上に二酸化マンガンと酸化モリブデンを析出さ
せた電極を陽極に用いて、電流密度０．１Ａ／ｃｍ２
以下で電解を行うと、陽極側で発生するガスが１００％
酸素ガスであり、塩素ガスが発生せず、環境面から好ま
しいからである。As the cathode, a copper plate is used for copper deposition, an aluminum plate is used for cadmium deposition, and an aluminum plate is used for zinc deposition, in consideration of the recovered metal species and current efficiency.
It is desirable to use a zinc plate or a galvanized steel plate. Further, the current density is preferably 0.1 A / cm 2 or less. The reason for this is that an electrode obtained by depositing manganese dioxide and molybdenum oxide on the used iridium oxide-coated titanium plate was used as an anode, and the current density was 0.1 A / cm 2.
When electrolysis is performed below, the gas generated on the anode side is 100%
This is because oxygen gas is used, and chlorine gas is not generated, which is preferable from an environmental point of view.
【００１６】電解析出により溶融中の金属イオン濃度が
下がる際の目安として、１０−４〜１０−２mol ／l 程
度に置き、あまり低い濃度まで反応をさせないようにす
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。As a guide when the concentration of metal ions during melting is lowered by electrolytic deposition, the concentration is set to about 10 −4 to 10 −2 mol / l so that the reaction does not proceed to a very low concentration. Because the metal ion concentration in the solution is 10 -4 mol
This is because the current efficiency is reduced to not more than 20% when the ratio is not more than / l.
【００１７】第３工程では、第１工程で固液分離した後
の固体残渣を水に投入してスラリーとし、このスラリー
を攪拌しながら塩酸、硝酸、硫酸などの鉱酸を添加して
ｐＨを１以下に調整し、鉛を抽出する。In the third step, the solid residue after solid-liquid separation in the first step is put into water to form a slurry, and a mineral acid such as hydrochloric acid, nitric acid or sulfuric acid is added to the slurry while stirring to adjust the pH. Adjust to 1 or less and extract lead.
【００１８】第４工程では、陰極として鉛板を使用し電
解析出により鉛を析出させる。また、電流密度および陽
極は第２工程と同じものであってよい。In the fourth step, lead is deposited by electrolytic deposition using a lead plate as a cathode. Further, the current density and the anode may be the same as those in the second step.
【００１９】第５工程では、第２工程と第４工程が終了
して銅、鉛、カドミウム、亜鉛の各イオン濃度が１０
−２mol ／l 以下になった溶液を合わせて用いて、第１
〜４工程を再度行う。In the fifth step, the second step and the fourth step are completed, and each ion concentration of copper, lead, cadmium and zinc is reduced to 10%.
-2 mol / l or less,
Repeat steps 4 to 4.
【００２０】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
して自身の溶解度にまで達して、第４工程において溶解
しなくなる。また、鉄、クロムは亜鉛めっき時に合金め
っきとして析出する。By repeating such an operation,
Aluminum, potassium, sodium and the like are gradually concentrated to reach their own solubility, and are not dissolved in the fourth step. Iron and chromium precipitate as alloy plating during zinc plating.
【００２１】実施例 （第１工程）まず、５００ｍｌビーカーに溶融飛灰１０
ｇを入れ、そこに０．１Ｎ−ＨＣｌ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４．２であった。Example (First Step) First, molten fly ash 10 was placed in a 500 ml beaker.
g, 200 ml of 0.1N-HCl was added thereto, 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 separation liquid was 4.2.
【００２２】（第２工程）その後、分離液中に、陽極と
して面積１０ｃｍ２ の酸化イリジウム被覆したチタン
上に二酸化マンガンと酸化モリブデンを析出させた電極
を、陰極として面積１０ｃｍ２ の銅板を入れて、０．
０５Ａ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
（ｖｓ．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。[0022] (second step) Then, in the separated liquid, the iridium oxide coated electrodes to precipitate molybdenum oxide and manganese dioxide on the titanium area 10 cm 2 as the anode, put the copper plate of area 10 cm 2 as the cathode , 0.
Electrolysis was performed at a constant current of 05A. At that time, the cathode potential was changed from -0.23 V (vs. standard hydrogen potential) to -0.30 V
(Vs. standard hydrogen potential), and the copper concentration is reduced from 0.17 (g / l) to 0.012 as shown in Table 1.
(G / l).
【００２３】その後、陰極を面積１０ｃｍ２ の亜鉛め
っき銅板に変えて同じく０．０５Ａの一定電流で電解し
た。その時、陰極電位は−０．３０Ｖ（ｖｓ．標準水素
電位）から−１．２１Ｖ（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３．２（ｇ
／ｌ）から０．０４８（ｇ／ｌ）まで減少した。Thereafter, the cathode was changed to a galvanized copper plate having an area of 10 cm 2 , and electrolysis was performed at a constant current of 0.05 A. At that time, the cathode potential gradually decreased from −0.30 V (vs. standard hydrogen potential) to −1.21 V (vs. standard hydrogen potential), and the zinc concentration was 3.2 (g) as shown in Table 1.
/ L) to 0.048 (g / l).
【００２４】（第３工程）第１工程で固液分離した後の
固体残渣８．５ｇを５００ｍｌのビーカーに入れ、その
中に、１Ｎ−ＨＣｌ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０．３８であった。(Third Step) 8.5 g of the solid residue after the solid-liquid separation in the first step is placed in a 500 ml beaker, and 170 ml of 1N HCl is placed therein and stirred at 50 ° C. for 1 hour to produce The resulting slurry was subjected to solid-liquid separation. The pH of the obtained separation liquid was 0.38.
【００２５】（第４工程）第３工程で得た分離液中に、
陽極として面積１０ｃｍ２ の酸化イリジウム被覆した
チタン上に二酸化マンガンと酸化モリブデンを析出させ
た電極を、陰極として面積１０ｃｍ２ の鉛板を入れ
て、０．０５Ａの一定電流で電解を行った。その時、陰
極電位は−０．４６Ｖ（ｖｓ．標準水素電位）から−
０．６９Ｖ（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１．４４（ｇ／ｌ）から
０．２１（ｇ／ｌ）まで減少した。(Fourth Step) In the separation liquid obtained in the third step,
The electrode was deposited molybdenum oxide and manganese dioxide on titanium and iridium oxide-coated area 10 cm 2 as the anode, put the lead plate of area 10 cm 2 as a cathode, subjected to electrolysis at a constant current of 0.05 A. At that time, the cathode potential was changed from -0.46 V (vs. standard hydrogen potential) to-
Gradually decreases to 0.69 V (vs. standard hydrogen potential),
The lead concentration was reduced from 1.44 (g / l) to 0.21 (g / l) as shown in Table 1.
【００２６】（第５工程）第２工程と第４工程を終えた
後の溶液を合わせて用いて、新しい飛灰に対し、より第
１工程〜第４工程を行った。その場合にも、表１の２回
目抽出液、２回目電解後液に示すように、１回目と同様
に抽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、抽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１０ｃｍ２ 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０．０５Ａの電流で電解した。この後は４回目ま
でと同様に陰極を亜鉛めっき鋼板に変更し、亜鉛のめっ
きを行った。各々の抽出操作時の収率は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) Using the solutions obtained after the completion of the second step and the fourth step, the first to fourth steps were further performed on fresh fly ash. In this case as well, extraction and electrolysis were performed in the same manner as in the first extraction, as shown in the second extraction solution and the second electrolysis solution in Table 1. When such an operation was repeated, the cadmium concentration in the extract became higher and the cadmium electrolysis became possible after the fifth time, so that -0.42 V (vs. standard hydrogen potential) was obtained during copper electrolysis.
At this time, the cathode was changed to an aluminum plate having an area of 10 cm 2 and electrolysis was performed at a current of 0.05 A until the voltage became −1.03 V (vs. standard hydrogen potential). Thereafter, the cathode was changed to a galvanized steel sheet and zinc plating was performed in the same manner as in the fourth time. The yield at the time of each extraction operation was 90% or more, and the efficiency at the time of electrolysis operation was 60% or more, indicating that heavy metals can be efficiently recovered from fly ash.
【００２７】[0027]
【表１】 [Table 1]
【００２８】[0028]
【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.
───────────────────────────────────────────────────── 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） Ｃ２５Ｃ 1/16 Ｃ２５Ｃ 7/02 ３０６ Ｃ２２Ｂ 13/06 1/18 19/30 7/02 ３０６ Ｂ０９Ｂ 3/00 ３０４Ｇ // Ｃ２２Ｂ 13/06 ＺＡＢ 15/00 Ｃ２２Ｂ 3/00 Ｑ 17/00 15/12 19/30 17/04 (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 CA35 CA50 4K001 AA06 AA09 AA20 AA30 BA14 BA19 DB04 DB21 DB23 4K058 AA21 BA21 BA24 BA25 BA27 BB04 CA03 CA04 CA05 CA13 CA20 EB13 EB15 ED01 ED03 ED04 FB03 FC07 FC14 FC22──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) C25C 1/16 C25C 7/02 306 C22B 13/06 1/18 19/30 7/02 306 B09B 3/00 304G // C22B 13/06 ZAB 15/00 C22B 3/00 Q 17/00 15/12 19/30 17/04 (72) Inventor Hiroshi Tatsumi 1-7-89 Minami Kohoku, Suminoe-ku, Osaka Nichidate Shipbuilding In-house F term (reference) 4D004 AA37 AB03 BA05 CA35 CA50 4K001 AA06 AA09 AA20 AA30 BA14 BA19 DB04 DB21 DB23 4K058 AA21 BA21 BA24 BA25 BA27 BB04 CA03 CA04 CA05 CA13 CA20 EB13 EB15 ED01 ED03 ED04 FB03 FC14 FC07
Claims (3)
飛灰から銅、カドミウム、亜鉛等の重金属を抽出し、該
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、銅、カドミウ
ム、亜鉛を分別して電解析出させ、その後、上記固液分
離で残った固体残渣のスラリーをｐＨ１以下に調整して
鉛を抽出し、該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電気化学的
重金属の回収方法。1. A fly ash slurry is adjusted to a pH of 1 or more to extract heavy metals such as copper, cadmium and zinc from the fly ash, and between a positive electrode and a negative electrode in a separated liquid obtained by solid-liquid separation of the slurry. Electrolysis is performed, and the cathode potential is gradually or stepwise changed in a negative direction to separate copper, cadmium, and zinc for electrolytic deposition, and then a slurry of the solid residue remaining in the solid-liquid separation described above. PH is adjusted to pH 1 or less to extract lead and electrolytically precipitate lead from a separated liquid obtained by solid-liquid separation of the slurry.
えた後の液を用いて、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
とする電気化学的重金属の回収方法。2. A new fly ash is subjected to metal extraction and electrolytic deposition according to the method of claim 1, using the liquid after the lead has been recovered by the method of claim 1. To recover electrochemical heavy metals.
陽極に、酸化イリジウム被覆したチタン上に二酸化マン
ガンと酸化モリブデンを析出させた電極または白金メッ
キしたチタン電極を使用し、陰極には、銅の電解析出時
には銅を、鉛の電解析出時には鉛あるいは鉛めっきした
鋼板を、カドミウムの電解析出時にはアルミニウムを、
亜鉛の電解析出時にはアルミニウム、亜鉛あるいは亜鉛
めっき鋼板を順番に取り替えて使用することを特徴とす
る電気化学的重金属の回収方法。3. The method according to claim 1, wherein
For the anode, use an electrode obtained by depositing manganese dioxide and molybdenum oxide on titanium coated with iridium oxide or a titanium electrode plated with platinum.For the cathode, use copper for electrolytic deposition of copper and lead for electrolytic deposition of lead. Alternatively, lead-plated steel sheet, aluminum at the time of electrolytic deposition of cadmium,
A method for recovering an electrochemical heavy metal, wherein aluminum, zinc or a galvanized steel sheet is replaced and used at the time of electrolytic deposition of zinc.
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| JP2001003384A JP3760261B2 (en) | 2001-01-11 | 2001-01-11 | Electrochemical recovery of heavy metals from fly ash |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005021174A1 (en) * | 2003-08-29 | 2005-03-10 | Geo5 R&D And Services Pte Ltd. | Method for electrokinetic remediation of incineration ash, industrial waste products and soft soil |
| US20120234137A1 (en) * | 2009-10-06 | 2012-09-20 | Elemetal Holding B.V. | Hydrometalurgical process and apparatus for recovering metals from waste material |
| CN109908527A (en) * | 2019-04-15 | 2019-06-21 | 武汉轻工大学 | A kind of garbage flying ash processing unit and the method for handling garbage flying ash |
| RU2750654C1 (en) * | 2020-07-09 | 2021-06-30 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Московский автомобильно-дорожный государственный технический университет (МАДИ)" | Method for regeneration of nitrate-ammonium solution of removing cadmium coatings |
-
2001
- 2001-01-11 JP JP2001003384A patent/JP3760261B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005021174A1 (en) * | 2003-08-29 | 2005-03-10 | Geo5 R&D And Services Pte Ltd. | Method for electrokinetic remediation of incineration ash, industrial waste products and soft soil |
| 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 |
| CN109908527A (en) * | 2019-04-15 | 2019-06-21 | 武汉轻工大学 | A kind of garbage flying ash processing unit and the method for handling garbage flying ash |
| RU2750654C1 (en) * | 2020-07-09 | 2021-06-30 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Московский автомобильно-дорожный государственный технический университет (МАДИ)" | Method for regeneration of nitrate-ammonium solution of removing cadmium coatings |
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| Publication number | Publication date |
|---|---|
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