JP4538890B2 - Heavy metal extraction method and method for measuring heavy metal elution amount - Google Patents
Heavy metal extraction method and method for measuring heavy metal elution amount Download PDFInfo
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- 229910001385 heavy metal Inorganic materials 0.000 title claims description 151
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- 238000010828 elution Methods 0.000 title claims description 37
- 239000002699 waste material Substances 0.000 claims description 57
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- 238000001914 filtration Methods 0.000 claims description 29
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Description
【０００１】
【発明の属する技術分野】
本発明は、重金属を高濃度で含有する焼却残渣や汚染土壌などの重金属含有廃棄物から、簡易な方法で重金属を効率的に抽出し、抽出残渣の重金属含有値を下げることにより、焼却残渣や汚染土壌の重金属汚染を軽減する方法に関する。本発明はまた、このような重金属含有廃棄物の重金属溶出量を簡易な方法で的確に測定する方法に関する。
【０００２】
【従来の技術】
ゴミ焼却炉から排出される焼却飛灰、灰溶融飛灰、焼却灰や電炉ダスト等は、一般に埋め立て処分されるが、これらは重金属を含有するため、そのまま埋め立て処分すると、埋め立て地周辺を有害な重金属で汚染することになる。このため、これらの重金属含有廃棄物の埋め立てに際しては、埋め立て地の環境保全のために、通常、含有される重金属を固定化してその溶出を防止するための処理が施されるが、一方で、重金属含有廃棄物から重金属を抽出除去して重金属の不溶化処理を不要ないし軽減する方法も知られている。
【０００３】
重金属含有廃棄物から重金属を抽出除去する方法としては、重金属含有廃棄物を水に溶解ないし懸濁させてスラリー化し、重金属を溶出させた後このスラリーを加圧濾過又は吸引濾過により固液分離する方法が一般的であり、この方法においてスラリーのｐＨを調整して各重金属を分離回収する方法も提案されている（特開平６−１７０３５４号公報等）。なお、特開平６−１７０３５４号公報記載の方法では、抽出に当たり、重金属含有飛灰に水を混合してスラリー状とするために、飛灰１００ｇに対して水２リットルを混合している。
【０００４】
一方、重金属含有廃棄物の重金属を不溶化処理するに当たっては、処理薬剤の必要量を決定するために、処理する重金属含有廃棄物からの重金属溶出量を測定したり、また、薬剤による処理効果を確認するために、処理物からの重金属溶出量を測定したりする必要がある。従来、この重金属溶出量の評価方法は、例えば環境庁告示１３号試験に従って実施されている。この環境庁告示１３号試験においては、水の添加量を試料、即ち、重金属含有廃棄物又は処理物の１０倍として６時間以上の振盪を行った後に、重金属の溶出量が測定される。
【０００５】
【発明が解決しようとする課題】
重金属含有廃棄物を水に溶解ないし懸濁させてスラリー状として重金属を溶出させる従来の重金属の抽出除去方法では、重金属の抽出効率が十分でなく、その向上が望まれていた。また、多量の水を添加してスラリー状とすることから、固液分離により発生する大量の分離液の処理の問題がある上に、抽出作業も煩雑で大掛かりなものとなる。
【０００６】
一方、環境庁告示１３号試験のように、試料に対して多量の水を添加して溶出試験を行う、従来の重金属溶出量の測定方法では、実際の埋め立て処分場における重金属の溶出状況を把握できない場合がある。即ち、実際の埋め立て処分場における水の存在比は、試料に対して１０倍量もの水を添加する測定条件よりも大幅に少ない場合が多く、このため試料に対して多量の水を添加する従来の測定方法では実際の溶出状況を再現して的確な評価を行うことはできない。しかも、従来の測定方法では、６時間以上もの振盪が必要であり、測定に長時間を要する上に、やはり、測定後に排出される多量の分離液の処理が必要となるという問題点もある。
【０００７】
本発明は上記従来の問題点を解決し、重金属含有廃棄物から簡易な方法で重金属を効率的に抽出除去する重金属抽出方法を提供することを目的とする。
【０００８】
本発明はまた、このような重金属含有廃棄物の重金属溶出量を簡易な方法で短時間に的確に測定することができる重金属溶出量の測定方法を提供することを目的とする。
【０００９】
【課題を解決するための手段】
本発明の重金属抽出方法は、重金属含有廃棄物に水を混合した後、好ましくは遠心濾過により遠心分離することにより、該重金属含有廃棄物中の重金属を抽出する方法であって、該重金属含有廃棄物に水／重金属含有廃棄物（重量比）が０．１〜１となるように水を混合し、該遠心分離が遠心濾過であり、該遠心濾過の回転数が４０００〜１００００ｒｐｍであることを特徴とする。
【００１０】
本発明の重金属溶出量の測定方法は、重金属含有廃棄物からの重金属溶出量を測定する方法であって、該重金属含有廃棄物に水／重金属含有廃棄物（重量比）が０．１〜１となるように水を混合した後、回転数４０００〜１００００ｒｐｍで遠心濾過し、濾液中の重金属含有量を測定することを特徴とする。
【００１１】
即ち、本発明者らは、重金属含有廃棄物から重金属を水中に溶出させて抽出する際の抽出効率を高めるべく、鋭意検討を重ねた結果、水／重金属含有廃棄物の混合重量比を０．１〜１という、従来法に比べて非常に少ない水量で抽出を行うと、重金属が水相に移行し易くなり、抽出効率が格段に向上することを見出し、本発明を完成させた。
【００１２】
重金属含有廃棄物にこのように少量の水を添加した場合、抽出系の外観は液状ないしスラリー状とはならず、従来の加圧濾過や吸引濾過では固液分離することができないが、遠心濾過によれば、効率的に固液分離することが可能となる。
【００１３】
本発明の重金属抽出方法及び重金属溶出量の測定方法では、処理対象の重金属含有廃棄物の近傍に存在する水分中（間隙水）のｐＨ、塩類濃度が高くなり、重金属の溶出が促進されると考えられる。このように高濃度で溶解している重金属類を遠心力により強制的に脱離することにより、重金属含有廃棄物中の重金属を効率的に水側へ溶出させることができる。
【００１４】
【発明の実施の形態】
以下に本発明の実施の形態を詳細に説明する。
【００１５】
本発明の重金属抽出方法においては、焼却飛灰等の重金属含有廃棄物に、水／重金属含有廃棄物の重量比が１以下で重金属含有廃棄物の外観が液（又はスラリー）状ないし泥状とならない程度に水を添加して混練機等で十分に混練する。この水添加量が水／重金属含有廃棄物の重量比で１を超えると、十分に重金属含有廃棄物中の重金属を溶出させて高い抽出効率で抽出を行うことができない。ただし、この水添加量は過度に少なくても抽出効率が悪くなり、その後の遠心分離での抽出液の回収率も悪くなることから、水／重金属含有廃棄物の重量比が０．１〜１．０、特に０．４〜０．６となるように水を添加するのが好ましい。
【００１６】
重金属含有廃棄物に水を添加して混練した後は遠心分離を行って抽出液を強制的に分離するが、水を添加して混練した後は、長時間放置せずに遠心分離を行うことが抽出効率の面で好ましく、一般的には、水を添加して混練後、一昼夜以内で遠心分離を行うのが好ましい。
【００１７】
この遠心分離としての遠心濾過で用いるフィルタとしては目開き０．４〜１．５μｍ程度のメンブレンフィルタやグラスフィルタ等が好適である。
【００１８】
また、遠心濾過の遠心分離の際の遠心力は大きい方が抽出効率が高いため好ましく、通常の場合、４０００Ｇ以上とするのが好ましい。また、この遠心分離の処理時間は３０分以上であることが好ましい。特にこの遠心分離は、４０００Ｇ以上で６０分以上行うのが、抽出液の回収効率の面で好ましい。ただし、この遠心分離を６０分以上で過度に長時間行ってもそれ以上抽出液の回収率の増加は望めない。この遠心分離時間は一般的には６０〜９０分程度行えば良い。
【００１９】
なお、本発明における抽出に当っては、ｐＨ調整を行わなくとも、高い抽出効率で重金属を抽出することができるが、４〜１２程度にｐＨ調整を行っても良い。
【００２０】
遠心濾過を空気中で行う場合、脱水に伴い水と置換して空気が重金属含有廃棄物に取り込まれ、空気中の二酸化炭素が重金属と不溶性の炭酸塩を生成し、抽出効率が低下することがある。これを防止するため不活性ガス雰囲気下で処理してもよい。
【００２１】
このような本発明の方法において、処理対象となる重金属含有廃棄物としては、特に制限はなく、焼却飛灰、灰溶融飛灰、焼却灰、電炉ダスト、汚染土壌などが挙げられ、また、これらを通常の重金属固定化方法で処理して得られた処理物であっても良い。
【００２２】
このような本発明の重金属抽出方法であれば、これらの重金属含有廃棄物中の重金属を効率的に抽出除去することができる。本発明の重金属抽出方法で得られる重金属抽出後の残渣は、溶出基準を満足する場合にはそのまま、満足しない場合には常法に従って重金属の不溶化処理を行った上で、埋め立て処分したり、土木・建設材料として再利用することができる。重金属を含有する抽出液は、重金属処理剤で重金属を不溶化し、固液分離して重金属を除去した後、その処理水は上記抽出のための混練水に再利用したり、蒸発乾固して塩を回収したり、或いは下水道などへ放流処分する。固液分離により得られる重金属が濃縮した固形分は鉱業原料として再利用することもできる。
【００２３】
本発明の重金属溶出量の測定方法は、上記抽出により得られた抽出液（濾液）中の重金属含有量を常法に従って測定するものであり、重金属含有廃棄物の重金属の溶出量を的確に求めることができる。
【００２４】
この方法は、特に、重金属含有廃棄物を埋め立て処分した場合の、処分場における重金属溶出可能性の評価に有効である。即ち、前述の如く、従来の評価方法、例えば環境庁告示１３号試験では、水の添加率を廃棄物の１０倍としたときの重金属溶出量を測定していた。しかし、処分場においては、水／重金属含有廃棄物の重量比が１程度となることもあり、その場合には１３号試験で測定されたよりも多量の重金属が溶出する。本発明の方法により重金属溶出量を測定すれば、１３号試験よりも実際の処分場での重金属の挙動をよく再現することができる可能性がある。また、従来の評価方法では長時間の振盪が必要であったが、本発明の方法であれば短時間に簡便に結果を得ることができ、測定後の廃液量も少ないため、その処理が軽減される。
【００２５】
本発明の重金属溶出量の測定方法は、被処理重金属含有廃棄物に適用して重金属固定化薬剤の必要量を決定したり、或いは、重金属固定化薬剤等で処理した後の重金属含有廃棄物に適用して、処理効果を確認したりする場合にも有効である。
【００２６】
【実施例】
以下に実施例及び比較例を挙げて、本発明をより具体的に説明する。
【００２７】
なお、以下において、重金属含有廃棄物としては、都市ゴミ清掃工場から採取した２種類の飛灰Ａ，Ｂを用いた。それぞれの飛灰の成分分析結果は表１に示す通りである。
【００２８】
【表１】
実施例１〜６、比較例１，２
飛灰Ａ，Ｂに、それぞれ蒸留水を飛灰重量に対して表２に示す量添加し、均一になるように良く混練した後、飛灰と水分をなじませるために一昼夜室内に放置した。
【００３０】
この湿潤飛灰を汎用の遠心濾過機（０．４５μｍメンブレンフィルタ）を利用して遠心濾過することにより湿潤飛灰中の重金属溶出液を採取した。この遠心濾過機は、図１（ａ）に示す如く、外筒１と内筒２との２重管構造となった試料容器３（短時間で遠心濾過を行うため、蓋なしの容器を用いた）の内筒２内に試料の湿潤飛灰４を入れ、回転体１０に取り付け、内筒２の底面に設けられたフィルタ５を遠心力により強制的に通過した分離液（重金属溶出液）を回収するものである。
【００３１】
この遠心濾過機の回転数は１００００ｒｐｍ（１７０００Ｇ）で、９０分間回転させた。なお、この遠心濾過により加水量の８割程度が回収される。
【００３２】
得られた重金属溶出液のＰｂ濃度から試料灰１ｋｇ当たりから抽出されたＰｂ量を算出すると共に、抽出率を算出し、結果を表２に示した。なお、表２には抽出液（重金属溶出液）のｐＨを併記した。
【００３３】
比較例３，４
１２５μｍ以下に粉砕した飛灰Ａ，Ｂ１６ｇにそれぞれ純水８００ｍＬを加え、スターラーで攪拌しながら、ｐＨコントローラーを用いて硝酸を滴下しながらこの溶出液（スラリー）をｐＨ７に維持して３時間溶出（抽出）操作を行った。３時間後、この溶出液を０．４５μｍメンブレンフィルターで濾過し、ｐＨ７の濾液及び残渣を得た。次に、残渣に再度８００ｍＬの蒸留水を加え、同様に溶出液をｐＨ４に３時間維持して溶出、濾過を行いｐＨ４の濾液及び残渣を得た。このｐＨ７及びｐＨ４の濾液を混合し、混合液中のＰｂ濃度を測定した。この溶出濃度から試料灰１ｋｇ当たりから抽出されたＰｂ量を算出すると共に抽出率を算出し、結果を抽出液のｐＨの測定結果と共に表２に示した。なお、この比較例３，４の抽出処理条件は、オランダの溶出試験法（ＮＥＮ７３４１，アベイラビリティ試験）と同じ手順である。
【００３４】
比較例５
飛灰Ａ５０ｇに蒸留水５００ｍＬを入れたボトルを６時間振盪して溶出操作を行った。６時間後、この溶出液（スラリー）を１μｍグラスファイバーペーパーフィルターで濾過し、濾液中のＰｂ濃度を測定した。この溶出濃度から試料灰１ｋｇ当たりから抽出されたＰｂ量を算出すると共に抽出率を算出し、結果を抽出液のｐＨの測定結果と共に表２に示した。なお、この比較例５の抽出処理条件は環境庁告示１３号試験と同じ手順である。
【００３５】
【表２】
表２より、本発明の重金属抽出方法によれば、高い抽出効率で重金属の抽出を行えることがわかる。
【００３７】
実施例７
実施例２において、飛灰Ａに水を添加した後の放置時間を０日（水添加後直ちに）、１日又は３日として遠心濾過し、更に、遠心濾過の回転数を４０００〜１００００ｒｐｍ（２５００〜１７０００Ｇ）の範囲で変えたこと以外は同様にして抽出操作を行い、抽出液のＰｂ濃度を調べ、結果を図２に示した。
【００３８】
図２より、遠心濾過の回転数が大きいほどＰｂ抽出濃度は高くなる傾向を示し、特にこの傾向は回転数４０００〜８０００ｒｐｍにおいて顕著であり、本発明における遠心力は５０００ｒｐｍ（４０００Ｇ）以上が適当であることがわかる。
【００３９】
【発明の効果】
以上詳述した通り、本発明の重金属抽出方法によれば、重金属含有廃棄物から簡易な方法で重金属を効率的に抽出除去することができる。本発明の重金属抽出方法で得られる抽出残渣は、その重金属含有量が著しく低減されているため、埋め立て処分に当たり、重金属の不溶化処理を省略するか或いは大幅に軽減することができる。しかも、抽出により発生する抽出液量が少ないため、その処理も容易となる上に、全体の抽出系容量が従来に比べて格段に少ないために、設備、作業面においても極めて有利である。
【００４０】
また、本発明の重金属溶出量の測定方法によれば、埋め立て処分場の環境を模擬、反映して的確かつ実用的な測定値を短時間で得ることができる。このため、重金属含有廃棄物の処理のための薬剤の必要量の決定或いは薬剤の処理効果の判定を確実に行うことが可能となり、埋め立て処分場での重金属の溶出を確実に防止することができる。
【図面の簡単な説明】
【図１】 実施例において用いた遠心濾過機の説明図であり、図１（ａ）は試料容器を示す断面図、図１（ｂ）は試料容器を回転体に取り付けた状態を示す断面図である。
【図２】 実施例７で求めた遠心濾過の回転数及び水添加後の放置日数と抽出液のＰｂ濃度との関係を示すグラフである。
【符号の説明】
１ 外筒
２ 内筒
３ 試料容器
４ 湿潤飛灰
５ フィルタ
６ 分離液
１０ 回転体[0001]
BACKGROUND OF THE INVENTION
The present invention efficiently extracts heavy metals from incineration residues containing heavy metals at high concentrations and wastes containing heavy metals such as contaminated soil by a simple method, and lowers the heavy metal content value of the extraction residues, thereby reducing incineration residues and The present invention relates to a method for reducing heavy metal contamination of contaminated soil. The present invention also relates to a method for accurately measuring the heavy metal elution amount of such heavy metal-containing waste by a simple method.
[0002]
[Prior art]
Incineration fly ash, ash melt fly ash, incineration ash and electric furnace dust discharged from garbage incinerators are generally disposed of in landfills, but these contain heavy metals. It will be contaminated with heavy metals. For this reason, when landfilling these heavy metal-containing wastes, in order to preserve the environment of the landfill site, usually a treatment for fixing the heavy metal contained and preventing its elution is performed, There is also known a method for extracting or removing heavy metals from waste containing heavy metals to eliminate or reduce the insolubilization treatment of heavy metals.
[0003]
As a method for extracting and removing heavy metals from waste containing heavy metal, the heavy metal containing waste is dissolved or suspended in water to form a slurry, and after elution of heavy metal, the slurry is subjected to solid-liquid separation by pressure filtration or suction filtration. A method is generally used, and a method for separating and recovering each heavy metal by adjusting the pH of the slurry in this method has also been proposed (JP-A-6-170354, etc.). In the method described in JP-A-6-170354, in extraction, 2 liters of water is mixed with 100 g of fly ash to mix water with heavy metal-containing fly ash to form a slurry.
[0004]
On the other hand, when insolubilizing heavy metals in waste containing heavy metals, the amount of heavy metals eluted from the heavy metal-containing waste to be treated is measured and the treatment effect of the chemicals is confirmed in order to determine the required amount of treatment chemicals. In order to achieve this, it is necessary to measure the amount of heavy metal elution from the treated product. Conventionally, this method for evaluating the amount of elution of heavy metals has been performed, for example, according to the Environmental Agency Notification No. 13 test. In this Environmental Agency Notification No. 13 test, the amount of water added is 10 times that of the sample, that is, the heavy metal-containing waste or treated material, and after 6 hours of shaking, the amount of elution of heavy metal is measured.
[0005]
[Problems to be solved by the invention]
In the conventional heavy metal extraction and removal method in which heavy metal-containing waste is dissolved or suspended in water to elute the heavy metal in a slurry state, the extraction efficiency of heavy metal is not sufficient, and improvement thereof has been desired. Further, since a large amount of water is added to form a slurry, there is a problem of processing a large amount of separation liquid generated by solid-liquid separation, and the extraction operation is complicated and large.
[0006]
On the other hand, as in the Environmental Agency Notification No. 13 test, a conventional method for measuring the elution amount of heavy metals, in which a large amount of water is added to the sample, grasps the elution status of heavy metals at the actual landfill site. There are cases where it is not possible. In other words, the ratio of water in an actual landfill site is often much less than the measurement conditions in which 10 times the amount of water is added to the sample, and thus a large amount of water is added to the sample. With this measurement method, the actual elution state cannot be reproduced and an accurate evaluation cannot be performed. In addition, the conventional measuring method requires shaking for 6 hours or more, and it takes a long time for the measurement, and there is also a problem that it is necessary to process a large amount of the separated liquid discharged after the measurement.
[0007]
An object of the present invention is to solve the above-described conventional problems and to provide a heavy metal extraction method for efficiently extracting and removing heavy metals from a heavy metal-containing waste by a simple method.
[0008]
Another object of the present invention is to provide a method for measuring a heavy metal elution amount capable of accurately measuring a heavy metal elution amount of such a heavy metal-containing waste in a short time by a simple method.
[0009]
[Means for Solving the Problems]
The heavy metal extraction method of the present invention is a method for extracting heavy metals in the heavy metal-containing waste by mixing water with the heavy metal-containing waste, and preferably centrifuging by centrifugal filtration. objects on mixing with water so that the water / heavy metal-containing waste (weight ratio) of 0.1 to 1, a centrifugal separation centrifugal filtration, speed 4000~10000rpm der Rukoto of centrifugal filtration It is characterized by.
[0010]
The method for measuring the heavy metal elution amount of the present invention is a method for measuring the heavy metal elution amount from the heavy metal-containing waste, wherein the water / heavy metal-containing waste (weight ratio) is 0.1 to 1 in the heavy metal-containing waste. after mixing the water so that the by centrifugal filtration at a rotational speed 4000～10000Rpm, and measuring the heavy metal content in the filtrate.
[0011]
That is, as a result of intensive investigations to increase extraction efficiency when heavy metals are eluted from water and extracted from heavy metal-containing waste, the present inventors have set the water / heavy metal-containing waste weight ratio to 0. say 1 to 1, when the extraction with very little amount of water as compared with the conventional method, the heavy metal is liable to migrate to the aqueous phase, extraction efficiency found that remarkably improved, and completed the present invention.
[0012]
If the addition of such small amounts of water to heavy metal-containing waste, the appearance of the extraction system does not become liquid or slurry, in the conventional pressure filtration and suction filtration can not be solid-liquid separation, centrifugal According to the filtration, it becomes possible to efficiently perform solid-liquid separation.
[0013]
In the heavy metal extraction method and heavy metal elution amount measurement method of the present invention, when the pH and salt concentration of water (pore water) existing in the vicinity of the heavy metal-containing waste to be treated are increased, elution of heavy metals is promoted. Conceivable. By forcibly detaching heavy metals dissolved in such a high concentration by centrifugal force, heavy metals in the heavy metal-containing waste can be efficiently eluted to the water side.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0015]
In the heavy metal extraction method of the present invention, the heavy metal-containing waste such as incineration fly ash has a water / heavy metal-containing waste weight ratio of 1 or less and the appearance of the heavy metal-containing waste is liquid (or slurry) or mud. Add water to such an extent that it does not become necessary and knead thoroughly with a kneader or the like. If the amount of water added exceeds 1 in terms of the weight ratio of water / heavy metal-containing waste, the heavy metal in the heavy metal-containing waste cannot be sufficiently eluted to perform extraction with high extraction efficiency. However, even if the amount of water added is too small, the extraction efficiency is deteriorated, and the recovery rate of the extract in the subsequent centrifugation is also deteriorated. Therefore, the weight ratio of the water / heavy metal-containing waste is 0.1 to 1. It is preferable to add water so that it may become 0.0, especially 0.4-0.6.
[0016]
After adding water to the heavy metal-containing waste and kneading, centrifuge it to forcibly separate the extract, but after adding water and knead, do not leave it for a long time and centrifuge it In view of extraction efficiency, it is generally preferable to centrifuge within one day and night after adding water and kneading.
[0017]
0.4~1.5μm about membrane filter and glass filter or the like to open the eye as a filter used in the centrifugal filtration as this centrifugation is preferred.
[0018]
Further, the centrifugal force during centrifugation over centrifugal filtration is preferred since it is the extraction efficiency higher large, usually preferably set to more than 4000 G. Moreover, it is preferable that the processing time of this centrifugation is 30 minutes or more. In particular, this centrifugation is preferably performed at 4000 G or more for 60 minutes or more from the viewpoint of recovery efficiency of the extract. However, even if this centrifugation is performed for 60 minutes or longer for an excessively long time, an increase in the recovery rate of the extract cannot be expected. In general, the centrifugation time may be about 60 to 90 minutes.
[0019]
In the extraction in the present invention, heavy metals can be extracted with high extraction efficiency without adjusting the pH, but the pH may be adjusted to about 4 to 12.
[0020]
When centrifugal filtration is performed in the air, water is replaced by dehydration and air is taken into the waste containing heavy metals, and carbon dioxide in the air generates heavy metals and insoluble carbonates, which may reduce the extraction efficiency. is there. In order to prevent this, the treatment may be performed in an inert gas atmosphere.
[0021]
In such a method of the present invention, the heavy metal-containing waste to be treated is not particularly limited, and examples include incineration fly ash, ash melt fly ash, incineration ash, electric furnace dust, and contaminated soil. May be a treated product obtained by treating with a conventional heavy metal immobilization method.
[0022]
If it is such a heavy metal extraction method of this invention, the heavy metal in these heavy metal containing waste can be efficiently extracted and removed. The residue after heavy metal extraction obtained by the heavy metal extraction method of the present invention is left as it is when the elution standard is satisfied, and when it is not satisfied, the heavy metal is insolubilized according to a conventional method, and then disposed of in landfill or civil engineering.・ Can be reused as construction material. The extract containing the heavy metal is insolubilized with a heavy metal treating agent, and after removing the heavy metal by solid-liquid separation, the treated water can be reused as kneading water for the above extraction or evaporated to dryness. Collect salt or discharge it to sewers. The solid content concentrated by heavy metal obtained by solid-liquid separation can be reused as a mining raw material.
[0023]
The method for measuring the amount of elution of heavy metals according to the present invention measures the amount of heavy metals in the extract (filtrate) obtained by the above extraction according to a conventional method, and accurately determines the amount of elution of heavy metals from waste containing heavy metals. be able to.
[0024]
This method is particularly effective for evaluating the possibility of elution of heavy metals at a disposal site when waste containing heavy metals is disposed of in landfills. That is, as described above, in the conventional evaluation method, for example, the Environmental Agency Notification No. 13 test, the elution amount of heavy metals was measured when the water addition rate was 10 times that of waste. However, at the disposal site, the weight ratio of water / heavy metal-containing waste may be about 1, and in that case, a larger amount of heavy metal is eluted than measured in the No. 13 test. If the amount of heavy metal elution is measured by the method of the present invention, there is a possibility that the behavior of heavy metal at an actual disposal site can be reproduced better than the No. 13 test. In addition, the conventional evaluation method required shaking for a long time, but with the method of the present invention, the results can be obtained easily in a short time, and the amount of waste liquid after measurement is small, reducing the processing. Is done.
[0025]
The method for measuring the heavy metal elution amount of the present invention is applied to waste to be treated containing heavy metal to determine the necessary amount of the heavy metal immobilizing agent, or to the heavy metal containing waste after being treated with the heavy metal immobilizing agent or the like. It is also effective when applied to check the processing effect.
[0026]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
[0027]
In the following, as the heavy metal-containing waste, two types of fly ash A and B collected from a municipal waste cleaning plant were used. The component analysis results of each fly ash are as shown in Table 1.
[0028]
[Table 1]
Examples 1 to 6, Comparative Examples 1 and 2
Distilled water was added to each of the fly ash A and B in the amount shown in Table 2 with respect to the fly ash weight, and kneaded well so as to be uniform.
[0030]
This wet fly ash was centrifugally filtered using a general-purpose centrifugal filter (0.45 μm membrane filter) to collect a heavy metal eluate in the wet fly ash. As shown in FIG. 1 (a), this centrifugal filter has a
[0031]
The centrifugal filter was rotated at 10000 rpm (17000 G) for 90 minutes. In addition, about 80% of the amount of water is recovered by this centrifugal filtration.
[0032]
The amount of Pb extracted from 1 kg of sample ash was calculated from the Pb concentration of the obtained heavy metal eluate, and the extraction rate was calculated. The results are shown in Table 2. In Table 2, the pH of the extract (heavy metal eluate) is also shown.
[0033]
Comparative Examples 3 and 4
Add 800 mL of pure water to each of 16 g of fly ash A and B crushed to 125 μm or less, stir with a stirrer, and add nitric acid dropwise using a pH controller while maintaining the eluate (slurry) at pH 7 for 3 hours ( Extraction) operation was performed. After 3 hours, the eluate was filtered through a 0.45 μm membrane filter to obtain a pH 7 filtrate and residue. Next, 800 mL of distilled water was added again to the residue, and the eluate was similarly maintained at pH 4 for 3 hours for elution and filtration to obtain a pH 4 filtrate and residue. The pH 7 and pH 4 filtrates were mixed, and the Pb concentration in the mixture was measured. The amount of Pb extracted from 1 kg of sample ash was calculated from the elution concentration, and the extraction rate was calculated. The results are shown in Table 2 together with the measurement result of the pH of the extract. The extraction processing conditions of Comparative Examples 3 and 4 are the same as the Dutch dissolution test method (NEN 7341, availability test).
[0034]
Comparative Example 5
The bottle containing 500 ml of distilled water in 50 g of fly ash A was shaken for 6 hours for elution. After 6 hours, the eluate (slurry) was filtered through a 1 μm glass fiber paper filter, and the Pb concentration in the filtrate was measured. The amount of Pb extracted from 1 kg of sample ash was calculated from the elution concentration, and the extraction rate was calculated. The results are shown in Table 2 together with the measurement result of the pH of the extract. In addition, the extraction process conditions of this comparative example 5 are the same procedures as the Environment Agency Notification No. 13 test.
[0035]
[Table 2]
From Table 2, it can be seen that the heavy metal extraction method of the present invention can extract heavy metals with high extraction efficiency.
[0037]
Example 7
In Example 2, centrifugal filtration was performed with the standing time after adding water to the fly ash A being 0 days (immediately after the addition of water), 1 day, or 3 days, and the rotational speed of centrifugal filtration was 4000 to 10000 rpm (2500 The extraction operation was carried out in the same manner except that it was changed in the range of ˜17000 G), the Pb concentration of the extract was examined, and the result is shown in FIG.
[0038]
FIG. 2 shows that the Pb extraction concentration tends to increase as the rotational speed of the centrifugal filtration increases. In particular, this tendency is remarkable at the rotational speed of 4000 to 8000 rpm, and the centrifugal force in the present invention is suitably 5000 rpm (4000 G) or more. I know that there is.
[0039]
【The invention's effect】
As described above in detail, according to the heavy metal extraction method of the present invention, heavy metals can be efficiently extracted and removed from the heavy metal-containing waste by a simple method. Since the heavy metal content of the extraction residue obtained by the heavy metal extraction method of the present invention is remarkably reduced, the heavy metal insolubilization treatment can be omitted or greatly reduced in landfill disposal. Moreover, since the amount of the extraction liquid generated by the extraction is small, the processing is easy, and the overall extraction system capacity is much smaller than the conventional one, which is extremely advantageous in terms of equipment and work.
[0040]
Further, according to the method for measuring the elution amount of heavy metal of the present invention, an accurate and practical measurement value can be obtained in a short time by simulating and reflecting the environment of the landfill disposal site. For this reason, it becomes possible to reliably determine the required amount of chemicals for processing heavy metal-containing waste or to determine the processing effect of chemicals, and to reliably prevent elution of heavy metals at a landfill site. .
[Brief description of the drawings]
FIG. 1 is an explanatory view of a centrifugal filter used in the examples, FIG. 1 (a) is a cross-sectional view showing a sample container, and FIG. 1 (b) is a cross-sectional view showing a state in which the sample container is attached to a rotating body. It is.
2 is a graph showing the relationship between the rotational speed of centrifugal filtration and the number of days left after addition of water and the Pb concentration of the extract obtained in Example 7. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Outer cylinder 2
Claims (14)
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2000001349A (en) * | 1998-06-09 | 2000-01-07 | Tokuyama Corp | Treatment of incineration ash of city garbage |
| JP2001524371A (en) * | 1997-11-28 | 2001-12-04 | エヌケイティ リサーチ センター アクティーゼルスカブ | Method for separating heavy metal and halogen from waste or residue |
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| JP3333910B2 (en) * | 1996-09-04 | 2002-10-15 | 住友大阪セメント株式会社 | Desalting method of exhaust gas dust of cement kiln |
| JPH11156338A (en) * | 1997-11-25 | 1999-06-15 | Agency Of Ind Science & Technol | Remedial method of contaminated soil |
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| JP2000001349A (en) * | 1998-06-09 | 2000-01-07 | Tokuyama Corp | Treatment of incineration ash of city garbage |
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| CN108647826A (en) * | 2018-05-11 | 2018-10-12 | 广东省生态环境技术研究所 | A kind of construction method and device of heavy metal-polluted soil environmental risk prediction model |
| CN108647826B (en) * | 2018-05-11 | 2021-03-30 | 广东省科学院生态环境与土壤研究所 | Construction method and device of soil heavy metal environmental risk prediction model |
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