JPH067782A - Treatment of heavy metal ion-containing waste solution - Google Patents
Treatment of heavy metal ion-containing waste solutionInfo
- Publication number
- JPH067782A JPH067782A JP4148912A JP14891292A JPH067782A JP H067782 A JPH067782 A JP H067782A JP 4148912 A JP4148912 A JP 4148912A JP 14891292 A JP14891292 A JP 14891292A JP H067782 A JPH067782 A JP H067782A
- Authority
- JP
- Japan
- Prior art keywords
- heavy metal
- sulfide
- waste liquid
- metal ion
- containing waste
- 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
Landscapes
- Removal Of Specific Substances (AREA)
Abstract
Description
【発明の詳細な説明】Detailed Description of the Invention
【０００１】[0001]
【産業上の利用分野】本発明は，めっき廃液等の重金属
イオン含有廃液を硫化物の存在下で高温高圧法により効
果的に処理する方法に関する。本発明は，さらに詳しく
は，シアン含有廃液の場合は熱加水分解によるシアン分
解後に残留した重金属イオン，特にニッケルイオンを効
果的に除去し，シアンを含有しない当該廃液の場合，た
とえば，ニッケルイオンとキレ−ト剤等を共に含有し，
重金属イオンの除去が不完全になり易い廃液の場合に
は，重金属イオンを効果的に除去するようにした重金属
イオン含有廃液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 effectively treating heavy metal ion-containing waste liquid such as plating waste liquid in the presence of sulfide by a high temperature and high pressure method. More specifically, the present invention more effectively removes heavy metal ions, especially nickel ions, remaining after the decomposition of cyanide by thermal hydrolysis in the case of a cyanide-containing waste liquid, and in the case of the waste liquid containing no cyanide, for example, nickel ions. Contains chelating agents, etc.,
The present invention relates to a method for treating a heavy metal ion-containing waste liquid that effectively removes heavy metal ions in the case of a waste liquid in which the removal of heavy metal ions is likely to be incomplete.
【０００２】[0002]
【従来の技術】銅，亜鉛，ニッケル等の重金属イオンを
含む高濃度シアン含有廃液（たとえば，めっき液）を熱
加水分解させ，シアンを分解処理することは日本工業新
聞社発行の技術雑誌「ＰＰＭ」の１９９７年，８月号５
８〜６７頁に記載されている通り，既に公知の技術であ
る。上記雑誌の記載事項の要点を記載すると，次の通り
である。熱加水分解処理の原理は，圧力容器内でシアン
化合物を加熱保持しシアンをアンモニア（ＮＨ3）と蟻
酸塩（ＨＣＯＯＫ）に分解し無毒化して排出可能にする
方法であり，反応式として最も単純なシアン化カリウム
に適用した場合は，次の反応式で示される。 ＫＣＮ＋２Ｈ2Ｏ→ＮＨ3＋ＨＣＯＯＫ （１） 鉄（Ｆｅ），亜鉛（Ｚｎ），ニッケル（Ｎｉ）などの金
属シアン錯塩では，反応を進行させるにはアルカリの添
加が必要で，アルカリの存在下で反応が進行しアンモニ
ア，蟻酸塩および金属酸化物と金属水酸化物に加水分解
される。また，Ｋ4Ｆｅ（ＣＮ）6（黄血塩）を使用した
場合の反応式は（２）式に示されている。 ６Ｋ4Ｆｅ（ＣＮ）6＋１２ＮａＯＨ＋６６Ｈ2Ｏ＋Ｏ2 ＝３６ＮＨ3＋２Ｆｅ3Ｏ4＋１２ＨＣＯＯＮａ＋２４ＨＣＯＯＫ （２） 上記の反応式（２）は，鉄シアン錯塩としての黄血塩が
単独に存在する廃液に関するものであるが，メッキ工場
や鉄鋼の軟窒化処理施設などではカリウムは高価なこと
から，カリウムの代わりにナトリウム（Ｎａ）が使用さ
れる。鉄シアン錯塩としての黄血塩の代わりに，ナトリ
ウムと鉄のシアン錯塩を対象とする場合は，上記反応式
（２）中のＫをＮａに読み替えるだけで良い。2. Description of the Related Art Wastewater containing a high concentration of cyanide (for example, a plating solution) containing heavy metal ions such as copper, zinc and nickel is thermally hydrolyzed to decompose cyanide by the technical magazine "PPM" published by Nihon Kogyo Shimbun. , August 1997, 5
As described on pages 8 to 67, this is a known technique. The main points of the items described in the above journal are as follows. The principle of the thermal hydrolysis treatment is a method in which a cyan compound is heated and held in a pressure vessel and cyan is decomposed into ammonia (NH 3 ) and formate (HCOOK) to be detoxified and can be discharged. When applied to various potassium cyanides, it is represented by the following reaction formula. KCN + 2H 2 O → NH 3 + HCOOK (1) Metal cyanide complex salts of iron (Fe), zinc (Zn), nickel (Ni), etc. require the addition of alkali in order to proceed the reaction, and react in the presence of alkali. Progresses and is hydrolyzed to ammonia, formate, and metal oxides and metal hydroxides. The reaction formula when K 4 Fe (CN) 6 (yellow blood salt) is used is shown in formula (2). 6K 4 Fe (CN) 6 + 12NaOH + 66H 2 O + O 2 = 36NH 3 + 2Fe 3 O 4 + 12HCOONa + 24HCOOK (2) The above reaction formula (2) relates to a waste liquid in which yellow blood salt as an iron cyanide complex salt exists alone. , Sodium (Na) is used instead of potassium because potassium is expensive in plating factories and steel nitrocarburizing facilities. When a cyanide complex salt of sodium and iron is used instead of the yellow blood salt as the iron cyanide complex salt, K in the above reaction formula (2) may be replaced by Na.
【０００３】メッキ工場などにおいて，鉄以外に使用さ
れる重金属としてはニッケル（Ｎｉ），亜鉛（Ｚｎ），
銅（Ｃｕ），カドミウム（Ｃｄ），金（Ａｕ），銀（Ａ
ｇ），クロム（Ｃｒ）その他数種が挙げられるが，その
中で代表的にニッケル，亜鉛，銅，カドミウムの４種と
ナトリウムとの，シアン錯塩のそれぞれについての熱加
水分解処理の反応の例を下記（３）〜（６）式に示す。 Ｎａ2Ｎｉ（ＣＮ）4＋２ＮａＯＨ＋８Ｈ2Ｏ ＝４ＮＨ3＋Ｎｉ（ＯＨ）2＋４ＨＣＯＯＮａ （３） Ｎａ2Ｚｎ（ＣＮ）4＋２ＮａＯＨ＋８Ｈ2Ｏ ＝４ＮＨ3＋Ｚｎ（ＯＨ）2＋４ＨＣＯＯＮａ （４） Ｎａ3Ｃｕ（ＣＮ）4＋ＮａＯＨ＋８Ｈ2Ｏ ＝４ＮＨ3＋Ｃｕ（ＯＨ）＋４ＨＣＯＯＮａ （５） Ｎａ2Ｃｄ（ＣＮ）4＋２ＮａＯＨ＋８Ｈ2Ｏ ＝４ＮＨ3＋Ｃｄ（ＯＨ）2＋４ＨＣＯＯＮａ （６） 上記の各反応式を対比すれば明白なように，（３）〜
（６）までのそれぞれの反応式は互いに極めて類似し，
熱加水分解処理による生成物は，アンモニアと，各重金
属の水酸化物および蟻酸塩である。従って，これらの重
金属シアン錯塩を含む混合廃液は，混合によって別の反
応が進行するようなものではなく，単純な反応系の混合
液として取り扱うことができ，上記重金属のそれぞれの
シアン錯塩の熱加水分解にも上記の反応式が適用でき
る。上記（３）〜（６）の反応式では，各重金属の水酸
化物が生成するものとして示されているが，圧力容器内
は高温，高圧下なので，脱水反応によって金属酸化物が
生成される。例として，ニッケル（Ｎｉ）と亜鉛（Ｚ
ｎ）について，熱加水分解により酸化物が生成される場
合の反応式を次に示す。 Ｎａ2Ｎｉ（ＣＮ）4＋２ＮａＯＨ＋７Ｈ2Ｏ ＝４ＮＨ3＋ＮｉＯ＋４ＨＣＯＯＮａ （７） ＮａＺｎ（ＣＮ）4＋２ＮａＯＨ＋７Ｈ2Ｏ ＝４ＮＨ3＋ＺｎＯ＋４ＨＣＯＯＮａ （８） 前記の重金属シアン錯塩の中で，熱加水分解法にとって
処理が困難なのは，銅シアン錯塩である。銅シアン錯塩
が主体となっている廃液の場合は，鉄シアン錯塩の添加
により反応が進行するようにできる。各種のめっき工場
や鉄鋼の軟窒化処理および液体浸炭処理施設からの混合
廃液を処理する場合には，通常廃液中にかなりの量の鉄
シアン錯塩が含まれている状態で供給されるので，鉄シ
アン錯塩を特に添加する必要は殆ど無い。表１は濃厚め
っき廃液について熱加水分解処理を行った場合の実験結
果を示すものである。同表に示す通り，濃厚めっき廃液
を熱加水分解処理した上澄み液（これを熱加水処理液と
いう）について重金属イオン等の含有量を調査した結
果，熱加水分解時に各重金属イオンの大部分は酸化物や
水酸化物となって沈澱除去されている状態が分かる。し
かし，このような熱加水分解処理だけでは，残存重金属
イオン量は表１に示すように，水質規制値を大幅にオ−
バ−しているのが実情であった。Heavy metals other than iron used in a plating plant or the like include nickel (Ni), zinc (Zn),
Copper (Cu), Cadmium (Cd), Gold (Au), Silver (A
g), chromium (Cr), and several other types, of which representative examples are four types of nickel, zinc, copper, and cadmium, and sodium, and examples of the reaction of thermal hydrolysis treatment of each of the cyan complex salts with sodium. Is shown in the following equations (3) to (6). Na 2 Ni (CN) 4 + 2NaOH + 8H 2 O = 4NH 3 + Ni (OH) 2 + 4HCOONa (3) Na 2 Zn (CN) 4 + 2NaOH + 8H 2 O = 4NH 3 + Zn (OH) 2 + 4HCOONa (4) Na 3 Cu (CN) 4 + NaOH + 8H 2 O = 4NH 3 + Cu (OH) + 4HCOONa (5) Na 2 Cd (CN) 4 + 2NaOH + 8H 2 O = 4NH 3 + Cd (OH) 2 + 4HCOONa (6) As apparent from comparison of the above reaction formulas , (3) ~
The reaction equations up to (6) are very similar to each other,
The products of the thermal hydrolysis treatment are ammonia and hydroxides and formates of each heavy metal. Therefore, the mixed waste liquid containing these heavy metal cyanide complex salts can be handled as a mixed liquid of a simple reaction system, which does not cause another reaction to proceed by mixing, and the thermal hydrolysis of each cyanide complex salt of the above heavy metals can be performed. The above reaction formula can also be applied to decomposition. In the reaction formulas (3) to (6) above, it is shown that hydroxides of each heavy metal are produced, but since the pressure vessel is under high temperature and high pressure, metal oxides are produced by dehydration reaction. . As an example, nickel (Ni) and zinc (Z
Regarding n), the reaction formula when an oxide is produced by thermal hydrolysis is shown below. Among Na 2 Ni (CN) 4 + 2NaOH + 7H 2 O = 4NH 3 + NiO + 4HCOONa (7) NaZn (CN) 4 + 2NaOH + 7H 2 O = 4NH 3 + ZnO + 4HCOONa (8) wherein the heavy metal cyanide complex process that difficult for the thermal hydrolysis method is ， It is a copper cyanide complex salt. In the case of a waste liquid mainly composed of copper cyanide complex salt, the reaction can be promoted by adding iron cyanide complex salt. When treating mixed effluents from various plating plants and steel soft nitriding and liquid carburizing facilities, iron is usually supplied in the state that a considerable amount of iron cyanide complex salt is contained in the effluent. It is almost unnecessary to add a cyan complex salt. Table 1 shows the experimental results when the concentrated plating waste liquid was subjected to the thermal hydrolysis treatment. As shown in the table, as a result of investigating the content of heavy metal ions, etc. in the supernatant liquid obtained by subjecting the concentrated plating waste liquid to the thermal hydrolysis treatment (this is referred to as the thermal hydrolysis treatment liquid), most of the heavy metal ions were oxidized during the thermal hydrolysis. It can be seen that the substances and hydroxides have been removed by precipitation. However, as shown in Table 1, the amount of residual heavy metal ions is significantly higher than the water quality regulation value only by such thermal hydrolysis treatment.
It was the actual situation that was being barred.
【０００４】[0004]
【表１】 [Table 1]
【０００５】また，めっき廃液等の重金属イオン含有廃
液で，上記シアン含有廃液以外の廃液，即ち，シアンを
含有しない重金属イオン含有廃液は，一般にその成分と
して表１の熱加水分解処理液の成分と同様の内容成分あ
るいは表１の原廃液からシアンを除いた成分を内容成分
とする場合が多い。一般的に，このような場合の廃液中
の重金属イオン類の除去方法としては，中和凝集沈澱法
や硫化物沈澱法が考えられる。硫化物沈殿法は臭気の点
で多少問題があるが，硫化物沈澱法の方が中和凝集沈澱
法よりも重金属イオンの除去性が良いといえる。表２
は，重金属イオン含有廃液を常温でその処理液に硫化ナ
トリウムを添加した時の各重金属イオンの残存量を調査
したものである。ｐＨについては７，１０および１３
と，また，硫化ナトリウムの添加量は０ｇ／ｌ，１０ｇ
／ｌおよび１５ｇ／ｌと変化させた条件で実験を行っ
た。[0005] Heavy metal ion-containing waste liquids such as plating waste liquids other than the above-mentioned cyan-containing waste liquids, that is, heavy metal ion-containing waste liquids that do not contain cyan, generally have the same components as those of the thermal hydrolysis treatment liquid of Table 1. In many cases, the same content component or a component obtained by removing cyan from the raw waste liquid in Table 1 is used as the content component. Generally, as a method for removing heavy metal ions in the waste liquid in such a case, a neutralization coagulation precipitation method or a sulfide precipitation method can be considered. Although the sulfide precipitation method has some problems in terms of odor, it can be said that the sulfide precipitation method has better removal of heavy metal ions than the neutralization coagulation precipitation method. Table 2
Is an investigation of the residual amount of each heavy metal ion when sodium sulfide was added to the treated liquid containing heavy metal ion at room temperature. About pH 7, 10 and 13
And, the addition amount of sodium sulfide is 0g / l, 10g
The experiment was carried out under the conditions that the values were changed to 1 / l and 15 g / l.
【０００６】[0006]
【表２】 [Table 2]
【０００７】表２の中央の欄に示すように，硫化ナトリ
ウム添加量を１０ｇ／ｌ（重金属イオン当量の約１０
倍）かつ，ｐＨ１０に調整した場合には，銅，鉄，亜鉛
の金属イオンは表１に記載した水質汚濁防止法の規制値
以内に処理が可能であることが示されている。しかし，
ニッケルイオンの残存量については，このような処理を
しても減少しないことが分かる。ニッケルイオンは水質
汚濁防止法での規制値はないが，神奈県公害防止条例で
は１ｐｐｍと規制されており，この規制値には遠く及ば
ない。即ち，従来技術の常温硫化物沈澱法では重金属イ
オン特にニッケルイオンの残存量が多いことによる微生
物処理の弊害及び硫化ナトリウムを過剰に添加するため
残存硫化物が多くなり，ＣＯＤ対策が必要になるという
弊害（問題点）があった。As shown in the center column of Table 2, the amount of sodium sulfide added was 10 g / l (about 10% of the heavy metal ion equivalent).
It has been shown that when the pH is adjusted to 10 times, the metal ions of copper, iron and zinc can be treated within the regulation values of the Water Pollution Control Law listed in Table 1. However,
It can be seen that the residual amount of nickel ions does not decrease even with such treatment. Nickel ion is not regulated by the Water Pollution Control Law, but it is regulated at 1ppm by the Kanagawa Prefectural Pollution Control Ordinance, which is far below this regulated value. That is, in the conventional room temperature sulfide precipitation method, the adverse effect of microbial treatment due to the large amount of heavy metal ions, especially nickel ions remaining, and the excessive addition of sodium sulfide, the amount of residual sulfide increases and COD countermeasures are required. There was a problem (problem).
【０００８】[0008]
【発明が解決しようとする課題】上記従来技術において
重金属イオンが十分除去できない理由としては，シアン
含有廃液を熱加水分解すると該廃液からアンモニアが発
生し，このアンモニアが重金属イオンと錯体を形成する
こと，または，めっき廃液中に含まれるＥＤＴＡ，ＮＴ
Ａ，グルコン酸ナトリウム，ロッシェル塩等のキレ−ト
剤と重金属イオンが錯体を形成することにより金属水酸
化物等の沈殿物を形成しなくなることによるものと考え
られる。なお，重金属イオン類を完全に除去することは
水質汚濁防止法の観点からも重要なことである。さらに
いえば，通常，重金属イオンの除去の処理後の工程で有
機汚濁物の処理に微生物処理を行っている場合が多く，
重金属イオン特に，Ｎｉイオンが残留すると微生物処理
に悪影響を及ぼすのでＮｉイオンの除去を行うことは重
要であるといえる。本発明は従来の上記課題（問題点）
を解決するようにした重金属イオン含有廃液の処理方法
を提供することを目的とするものである。The reason why heavy metal ions cannot be sufficiently removed in the above-mentioned prior art is that when the cyanide-containing waste liquid is thermally hydrolyzed, ammonia is generated from the waste liquid, and the ammonia forms a complex with the heavy metal ions. , Or EDTA, NT contained in the plating waste liquid
It is considered that this is because the chelating agent such as A, sodium gluconate, and Rochelle salt and the heavy metal ion do not form a precipitate such as a metal hydroxide by forming a complex. Complete removal of heavy metal ions is also important from the viewpoint of the Water Pollution Control Law. Furthermore, usually, in many cases, microbial treatment is used to treat organic pollutants in the step after the treatment for removing heavy metal ions,
It can be said that it is important to remove Ni ions because heavy metal ions, especially Ni ions, adversely affect microbial treatment. The present invention has the above-mentioned conventional problems (problems)
It is an object of the present invention to provide a method for treating a heavy metal ion-containing waste liquid that solves the above problem.
【０００９】[0009]
【課題を解決するための手段】本発明の発明者等は重金
属イオンの除去，特に，ニッケルイオンの除去と硫化ナ
トリウム添加量の低減とを目的として種々の検討，実験
を行った結果，めっき廃液等の重金属イオン含有廃液の
処理方法として，オ−トクレ−ブ法（高温，高圧下）と
硫化物沈澱法とを巧みに組み合わせることにより重金属
イオンをほぼ完全に除去する処理方法を見い出した。そ
の処理方法とは，重金属イオン含有廃液に硫化物を添加
し，高温，高圧に所要時間保持するようにした重金属イ
オン含有廃液の処理方法である。また，この処理方法に
は，重金属イオンを含むシアン含有廃液を熱加水分解処
理したのち，該処理廃液に硫化物を添加し，高温，高圧
に所要時間保持するようにしたシアン含有廃液の熱加水
分解後の重金属イオン廃液の処理方法も含まれる。上記
の各処理方法において，高温の条件は１３０〜２５０
℃，また，高圧の条件としては２．７×１０5〜４０×
１０5Ｐａとすることが望ましい。また，硫化物として
は硫化アルカリ金属塩または硫化アンモニウム塩または
硫化水素を用いることが望ましい。また，シアン含有廃
液の熱加水分解後の重金属イオン廃液の処理方法におけ
る硫化物の添加量としては，熱加水分解前のシアン含有
廃液中の重金属イオン（Ｍｅ）の量に対する硫黄イオン
の当量比（Ｓ／Ｍｅ）で，０．６以上の量を選択するこ
とが望ましい。まず，本発明における必須要件の硫化物
について述べる。即ち，後述する表３，表４に示すよう
に，所定の高温，高圧下で，重金属イオン含有廃液に所
要の硫化ナトリウムを添加すると，重金属イオン，特
に，ニッケルイオン残存量が減少し，残留硫化物も少な
くなり，後工程の２次処理にも影響が少なくなることが
確認された。また，添加物として硫化ナトリウムは上記
の通り金属イオン除去の効果が認められるが，さらに，
硫化ナトリウム以外の硫化物について実験したところ，
硫黄を除き硫化カリウム，硫化アンモニウム，硫化水素
等，多くの硫化物で同様の金属イオン除去の効果が認め
られた。これらの硫化物の添加量（Ｓ--として）は対金
属当量比で０．８の場合でかなり良い効果を示し，１．
０以上で非常に良い結果が得られた。硫化物の添加量が
増えると残留硫化物が増えるので，添加量はなるべく対
金属当量比で１．０から２．０の範囲が好ましい。さら
に，本発明における高温，高圧条件について述べる。後
述の表４から次のことがいえる。１０ｇ／ｌの硫化ナト
リウムの添加という同一条件下で実験した場合，温度，
圧力が１００℃，１．０×１０5Ｐａの時にはＮｉは１
３３．５というかなりの残存量が認められた。しかし，
１３０℃，２．７×１０5ＰａではＮｉは４．０という
低い濃度まで下がり，他の金属イオンはほとんど除去で
きた。さらに，２１０℃，１９×１０5Ｐａとした時
は，ニッケル残存量が０．５ｐｐｍとなり，これは神奈
川県の規制値以下となった。即ち，一般に反応器を２５
０℃以上に上げるのは耐圧力容器に関する法規制上困難
なため，硫化物の添加時の温度は１３０℃〜２５０℃が
望ましい。従って，圧力は２．７×１０5Ｐａ〜４０×
１０5Ｐａが望ましい。硫化物添加時の反応時間は上記
温度，圧力範囲で少なくとも５分間は必要でありそれ以
下では残留Ｎｉイオン量が多くなる傾向がある。さら
に，本発明における重金属イオン含有廃液のＰＨ条件に
ついて述べると次の通りである。即ち，ＰＨ条件は除去
したい金属イオンによって異なるが，本発明の場合には
ＰＨ７以上であることが好ましく，より好ましいＰＨ条
件は，ＰＨ９以上である。ＰＨ７未満の場合は重金属イ
オン除去効率が低下する。The inventors of the present invention have conducted various studies and experiments for the purpose of removing heavy metal ions, in particular, removing nickel ions and reducing the amount of sodium sulfide added. As a method for treating a waste liquid containing heavy metal ions such as the above, we have found a treatment method that removes heavy metal ions almost completely by skillfully combining the autoclave method (under high temperature and high pressure) and the sulfide precipitation method. The treatment method is a treatment method of a heavy metal ion-containing waste liquid in which a sulfide is added to the heavy metal ion-containing waste liquid and is kept at high temperature and high pressure for a required time. In this treatment method, a cyanide-containing waste liquid containing heavy metal ions is subjected to a thermal hydrolysis treatment, and then a sulfide is added to the treated waste liquid so that the cyanide-containing waste liquid is kept at high temperature and high pressure for a required time. A method of treating heavy metal ion waste liquid after decomposition is also included. In each of the above processing methods, the high temperature condition is 130 to 250.
℃, high pressure condition is 2.7 × 10 5 to 40 ×
It is desirable to set it to 10 5 Pa. As the sulfide, it is desirable to use alkali metal sulfide, ammonium sulfide, or hydrogen sulfide. In addition, as the amount of sulfide added in the method for treating heavy metal ion waste liquid after thermal hydrolysis of cyanide-containing waste liquid, the equivalent ratio of sulfur ions to the amount of heavy metal ions (Me) in the cyanide-containing waste liquid before thermal hydrolysis ( In S / Me), it is desirable to select an amount of 0.6 or more. First, the essential sulfide in the present invention will be described. That is, as shown in Tables 3 and 4 described later, when the required sodium sulfide is added to the heavy metal ion-containing waste liquid at a predetermined high temperature and high pressure, the residual amount of heavy metal ions, particularly nickel ions, is reduced and It was also confirmed that the amount of waste was reduced and the secondary treatment in the post process was less affected. Also, sodium sulfide as an additive has the effect of removing metal ions as described above.
When we experimented with sulfides other than sodium sulfide,
Except for sulfur, many sulfides such as potassium sulfide, ammonium sulfide, hydrogen sulfide, etc. were found to have the same effect of removing metal ions. The amount of the sulfide (S - as) represents a fairly good effect in the case of 0.8-to-metal equivalent ratio, 1.
Very good results were obtained at 0 or more. Since the residual sulfide increases as the added amount of sulfide increases, the added amount is preferably in the range of 1.0 to 2.0 in terms of metal equivalent ratio. Further, the high temperature and high pressure conditions in the present invention will be described. The following can be said from Table 4 below. When tested under the same conditions of addition of 10 g / l sodium sulfide, the temperature,
When the pressure is 100 ° C. and 1.0 × 10 5 Pa, Ni is 1
A considerable residual amount of 33.5 was observed. However,
At 130 ° C. and 2.7 × 10 5 Pa, Ni dropped to a low concentration of 4.0, and most of the other metal ions could be removed. Further, when the temperature was 210 ° C. and 19 × 10 5 Pa, the residual nickel amount was 0.5 ppm, which was below the regulation value of Kanagawa prefecture. That is, generally 25 reactors
Since it is difficult to raise the temperature to 0 ° C. or higher due to the legal regulations relating to the pressure resistant container, the temperature during addition of the sulfide is preferably 130 ° C. to 250 ° C. Therefore, the pressure is 2.7 × 10 5 Pa to 40 ×
10 5 Pa is desirable. The reaction time at the time of adding sulfides is required to be at least 5 minutes within the above temperature and pressure ranges, and the amount of residual Ni ions tends to increase below that. Further, the PH conditions of the waste liquid containing heavy metal ions in the present invention will be described as follows. That is, the PH condition varies depending on the metal ion to be removed, but in the case of the present invention, it is preferably PH7 or more, and more preferably PH9 or more. If it is less than PH7, the efficiency of removing heavy metal ions decreases.
【００１０】[0010]
【作用】鉄，銅，亜鉛，ニッケルの各イオンを含むシア
ン含有廃液の熱加水分解反応は，（９）〜（13）式に示
す反応をするものと考えられる。また，鉄以外の金属イ
オンは水酸化物だけでなく一部酸化物も形成していると
思われる。Ｆｅイオンはアンモニア錯体を作らず，Ｆｅ
3Ｏ4の形で殆ど沈澱するので除去は容易である。 ＮａＣＮ＋２Ｈ2Ｏ＝ＮＨ3＋ＨＣＯＯＮａ ・・・・・・・・・・・・・・・・・・・・・・・（９） Ｎａ4Ｆｅ（ＣＮ）6＋２ＮａＯＨ＋１１Ｈ2Ｏ＋１／６０2 ＝６ＮＨ3＋６ＨＣＯＯＮａ＋１／３Ｆｅ3Ｏ4・・・・（10） Ｎａ3Ｃｕ（ＣＮ）4＋ＮａＯＨ＋８Ｈ2Ｏ ＝４ＮＨ3＋Ｃｕ（ＯＨ）＋４ＨＣＯＯＮａ・・・・・・（11） Ｎａ2Ｚｎ（ＣＮ）4＋２ＮａＯＨ＋８Ｈ2Ｏ ＝４ＮＨ3＋Ｚｎ（ＯＨ）2＋４ＨＣＯＯＮａ・・・・・（12） Ｎａ2Ｎｉ（ＣＮ）4＋２ＮａＯＨ＋８Ｈ2Ｏ ＝４ＮＨ3＋Ｎｉ（ＯＨ）2＋４ＨＣＯＯＮａ・・・・・（13）The thermal hydrolysis reaction of the cyanide-containing waste liquid containing iron, copper, zinc, and nickel ions is considered to be the reaction represented by the equations (9) to (13). Moreover, it is considered that metal ions other than iron form not only hydroxides but also some oxides. Fe ions do not form ammonia complex,
It is easy to remove as it mostly precipitates in the form of 3 O 4 . NaCN + 2H 2 O = NH 3 + HCOONa (9) Na 4 Fe (CN) 6 + 2NaOH + 11H 2 O + 1/60 2 = 6NH 3 + 6HCOONa + 1 / 3Fe 3 O 4 ···· (10 ) Na 3 Cu (CN) 4 + NaOH + 8H 2 O = 4NH 3 + Cu (OH) + 4HCOONa ······ (11) Na 2 Zn (CN) 4 + 2NaOH + 8H 2 O = 4NH 3 + Zn (OH) 2 + 4HCOONa ····· (12) Na 2 Ni (CN) 4 + 2NaOH + 8H 2 O = 4NH 3 + Ni (OH) 2 + 4HCOONa ····· (13)
【００１１】一方，他の金属イオンは熱加水分解で発生
したアンモニアと（14）〜（15）式のようなアンモニア
錯体を形成する。 Ｃｕ＋４ＮＨ3＝〔Ｃｕ（ＮＨ3）4〕2+ ・・・・・・・・・・・・・・・・・・・・・（14） Ｚｎ＋４ＮＨ3＝〔Ｚｎ（ＮＨ3）4〕2+ ・・・・・・・・・・・・・・・・・・・・・（15） Ｎｉ＋６ＮＨ3＝〔Ｎｉ（ＮＨ3）6〕2+ ・・・・・・・・・・・・・・・・・・・・・（16） 高温，高圧下で硫化ナトリウムを添加すると 〔Ｃｕ（ＮＨ3）4〕2+＋Ｓ2-＝ＣｕＳ↓＋４ＮＨ3 ・・・・・・・・・・・・・・・（17） 〔Ｚｎ（ＮＨ3）4〕2+＋Ｓ2-＝ＺｎＳ↓＋４ＮＨ3 ・・・・・・・・・・・・・・・（18） 〔Ｎｉ（ＮＨ3）6〕2+＋Ｓ2-＝ＮｉＳ↓＋６ＮＨ3 ・・・・・・・・・・・・・・・（19） となり，金属イオン類は硫化物の沈澱を作り容易に除去
できる。めっき廃液にはグルコン酸塩，ロッシェル塩，
ＥＤＴＡ，ＮＴＡ等のキレ−ト剤が入っており，これら
と銅，亜鉛，ニッケル等の各イオンが安定なキレ−ト化
合物を形成している。そのため常温においては硫化物を
添加しても重金属イオンは除去しにくい。しかし，硫化
物を添加して熱加水分解すれば重金属除去効率は大幅に
向上し，さらに，シアン分解後，高温，高圧下で硫化物
を添加すれば表３のように，より効果的に重金属は除去
されている。On the other hand, other metal ions form an ammonia complex represented by the formulas (14) to (15) with ammonia generated by thermal hydrolysis. Cu + 4NH 3 = [Cu (NH 3) 4] 2+ ····················· (14) Zn + 4NH 3 = [Zn (NH 3) 4] 2+ (15) Ni + 6NH 3 = [Ni (NH 3 ) 6 ] 2+ (16) When sodium sulfide is added at high temperature and high pressure, [Cu (NH 3 ) 4 ] 2+ + S 2- = CuS ↓ + 4NH 3・ ・ ・ ・ (17) [Zn (NH 3 ) 4 ] 2+ + S 2- = ZnS ↓ + 4NH 3・ ・ ・ ・ ・ ・ ・ ・ ・ ・ (18) [Ni (NH 3 ) 6 ] 2+ + S 2 − = NiS ↓ + 6NH 3 ····································· (19), the metal ions can be easily removed by forming a sulfide precipitate. For plating waste liquid, gluconate, Rochelle salt,
It contains a chelating agent such as EDTA and NTA, and these ions such as copper, zinc and nickel form a stable chelating compound. Therefore, at room temperature, it is difficult to remove heavy metal ions even if sulfide is added. However, if sulfides are added and subjected to thermal hydrolysis, the removal efficiency of heavy metals is significantly improved. Furthermore, if sulfides are added at high temperature and high pressure after the decomposition of cyanide, as shown in Table 3, it is more effective. Have been removed.
【００１２】比較例１，２，３ 全シアン16400ｐｐｍ，Ｆｅ480ｐｐｍ，Ｃｕ3900ｐｐ
ｍ，Ｚｎ1600ｐｐｍおよびＮｉ1500ｐｐｍ，その他若干
の重金属イオンを含む混合めっき老廃液をオ−トクレ−
ブに入れ，比較例１，２及び３として熱加水分解前に対
金属当量比で１．０，１．２および２．０の硫化ナトリ
ウムを添加し，２１０℃，１９×１０5Ｐａ（１９×１
０5Ｐａは２１０℃の水の飽和蒸気圧を示す）６時間熱
加水分解させ，処理液を濾紙（ＮＯ５Ｃ）でろ過し重金
属イオン類の分析をした結果を表３の左欄に示す。この
結果，表３の左欄に示すように，対金属当量比で１．０
の硫化ナトリウムを入れても重金属イオン類はかなり残
り，さらに硫化ナトリウムの添加量を増やし，対金属当
量比で２．０入れても，Ｎｉイオンは１．０ｐｐｍ以下
にはならないことが確認された。Comparative Examples 1, 2, 3 Total cyan 16400ppm, Fe 480ppm, Cu 3900pp
m, Zn1600ppm and Ni1500ppm, and other mixed plating waste liquid containing some heavy metal ions are autoclaved.
In Comparative Example 1, 2, and 3, sodium sulfide having a metal equivalent ratio of 1.0, 1.2, and 2.0 was added before thermal hydrolysis, and 210 ° C., 19 × 10 5 Pa (19 × 1
0 5 Pa to saturate showing the vapor pressure) for 6 hours thermal hydrolysis of 210 ° C. water, shows the results of the processing solution was analyzed for filtered heavy ions with filter paper (NO5C) in the left column of Table 3. As a result, as shown in the left column of Table 3, the metal-to-metal equivalent ratio was 1.0
It was confirmed that even if the sodium sulfide was added, heavy metal ions remained considerably, and even if the amount of sodium sulfide added was increased and the ratio of metal equivalent to 2.0 was added, the Ni ion did not fall below 1.0 ppm. .
【００１３】比較例４ 次に，上記のめっき廃液を硫化ナトリウムを添加せず，
同条件で熱加水分解させ，シアン分解後，２１０℃，１
９×１０5Ｐａ，の高温，高圧下で原廃液の対金属当量
比で０．５の硫化ナトリウムを入れ５分間保持し冷却し
た。この処理液を濾紙（ＮＯ５Ｃ）でろ過し，重金属イ
オン類の分析を行った結果を表３の右欄に示す。この場
合，対金属当量比で０．５で各重金属イオンは若干では
あるがさがるという結果が得られた。Comparative Example 4 Next, the above plating waste liquid was added to the above without adding sodium sulfide,
Thermally hydrolyzed under the same conditions, after cyanide decomposition, 210 ℃, 1
Under a high temperature and high pressure of 9 × 10 5 Pa, sodium sulfide having a metal equivalent ratio of 0.5 to the raw waste liquid was added, and the mixture was kept for 5 minutes and cooled. The treatment liquid is filtered through a filter paper (NO5C) and the heavy metal ions are analyzed. The results are shown in the right column of Table 3. In this case, the result was obtained in which the weight ratio of metal to metal was 0.5, but the amount of each heavy metal ion slightly decreased.
【００１４】比較例５ また，この時の温度による効果を調べるために，上記の
比較例４と同様な処理条件で熱加水分解後，反応器の温
度，圧力を１００℃，１．０×１０5Ｐａで硫化ナトリ
ウムを対金属当量比で１．０添加し５分間保持後冷却
し，ろ過水の金属イオン濃度を分析した結果を表４に示
す。この場合，同表に示すように，Ｎｉを除く各重金属
イオンは低位までさがることが示されている。Comparative Example 5 Further, in order to investigate the effect of temperature at this time, after thermal hydrolysis under the same processing conditions as in Comparative Example 4, the temperature and pressure of the reactor were 100 ° C. and 1.0 × 10 6. Table 4 shows the results of analyzing the metal ion concentration of filtered water by adding sodium sulfide 1.0 at 5 Pa in a metal equivalent ratio of 1.0, holding for 5 minutes and then cooling. In this case, as shown in the same table, it is shown that each heavy metal ion except Ni is lowered to a low level.
【００１５】[0015]
実施例１，２ 本発明の実施例１及び実施例２の場合として，上記のめ
っき廃液を硫化ナトリウムを添加せず，同条件で熱加水
分解させ，シアン分解後，２１０℃，１９×１０5Ｐ
ａ，の高温，高圧下で原廃液の対金属当量比で０．８及
び１．０の硫化ナトリウムを入れ５分間保持し冷却し
た。この処理液を濾紙（ＮＯ５Ｃ）でろ過し，重金属イ
オン類の分析を行った結果を表３の右欄に示す。この場
合，実施例１の場合でもＮｉを含む各重金属イオンは低
位までさがり，そして，実施例２の場合には，Ｎｉイオ
ンでも１．０ｐｐｍ以下の値にまでさがるという，良い
結果が得られた。 実施例２．３ ，実施例２，３の各場合における温度による効果を調べ
るために，上記の実施例１，２と同様な処理条件で熱加
水分解後，反応器の温度，圧力を１３０℃，２．７×１
０5Ｐａ（実施例３）及び２１０℃，１９×１０5Ｐａ
（実施例２）で硫化ナトリウムを対金属当量比で１．０
添加し５分間保持後冷却し，ろ過水の金属イオン濃度を
分析した結果を表４に示す。同表に示すように，実施例
３の場合である１３０℃，２．７×１０5 Ｐａでの硫化
ナトリウムの添加でかなりの重金属除去作用が認めら
れ，さらに，実施例２の場合である２１０℃，１９×１
０5 Ｐａで硫化ナトリウムの添加では問題のＮｉが０．
５ｐｐｍ迄低下している様子が分かる。Examples 1 and 2 In the case of Examples 1 and 2 of the present invention, the above plating waste liquid was hydrolyzed under the same conditions without adding sodium sulfide, and after cyan decomposition, 210 ° C., 19 × 10 5 P
Under a high temperature and high pressure of a, sodium sulfide having a metal equivalent ratio of 0.8 and 1.0 in the raw waste liquid was charged and held for 5 minutes to cool. The treatment liquid is filtered through a filter paper (NO5C) and the heavy metal ions are analyzed. The results are shown in the right column of Table 3. In this case, good results were obtained in which even in the case of Example 1, each heavy metal ion containing Ni went down to a low level, and in the case of Example 2, the Ni ion also went down to a value of 1.0 ppm or less. . In order to investigate the effect of temperature in each of Examples 2.3 and 2 and 3, after thermal hydrolysis under the same treatment conditions as in Examples 1 and 2, the reactor temperature and pressure were set to 130 ° C. , 2.7 × 1
0 5 Pa (Example 3) and 210 ° C., 19 × 10 5 Pa
In Example 2, sodium sulfide was 1.0 in terms of metal equivalent ratio.
Table 4 shows the results of analyzing the metal ion concentration of the filtered water after adding and holding for 5 minutes and cooling. As shown in the table, a considerable heavy metal removing action was recognized by the addition of sodium sulfide at 130 ° C. and 2.7 × 10 5 Pa, which is the case of Example 3, and 210 of Example 2. ℃, 19 × 1
At 0 5 Pa, the addition of sodium sulfide resulted in the problem that the Ni content was 0.
It can be seen that it has dropped to 5 ppm.
【００１６】[0016]
【表３】 [Table 3]
【００１７】[0017]
【表４】 上記の実施例のものは，重金属イオンを含む混合めっき
老廃液の熱加水分解後のシアン廃液の後処理としての重
金属イオンの除去処理について述べたが，このような熱
加水分解後のシアン廃液からの重金属イオンの除去に限
らず，各種の重金属イオン含有液，特に，Ｎｉとキレ−
ト剤を含有する重金属イオン含有液からの重金属イオン
の除去に有効な処理方法であることは勿論である。[Table 4] In the above-mentioned embodiment, the heavy metal ion removal treatment as the post-treatment of the cyan waste liquid after the thermal hydrolysis of the mixed plating waste liquid containing the heavy metal ions is described. Not limited to the removal of heavy metal ions, various liquids containing heavy metal ions, especially Ni and
Needless to say, the treatment method is effective for removing heavy metal ions from a heavy metal ion-containing liquid containing a coating agent.
【００１８】[0018]
【発明の効果】重金属イオン含有めっき廃液等には，グ
ルコン酸塩，ロッシェル塩，ＥＤＴＡ，ＮＴＡ等のキレ
−ト剤が多量に含まれている場合が多く，これらのキレ
−ト剤及びアンモニアにより，重金属イオン類がキレ−
ト化合物やアンモニア錯体を作るため除去されにくい。
それ故，重金属イオン類除去のため，ｐＨの調整や硫化
ナトリウムの多量の添加をしても，重金属イオン類の除
去は容易でなく，Ｎｉイオンについては殆ど除去できな
かった。しかし，本発明により，これらの重金属イオン
含有廃液に硫化物を添加し，高温，高圧に所要時間保持
するという処理を行うことによって，従来は除去できな
かったＮｉイオンを含む重金属イオン類を安価，確実に
除去できるので，その実利は大である。EFFECTS OF THE INVENTION Heavy metal ion-containing plating waste liquids often contain a large amount of chelating agents such as gluconate, Rochelle salt, EDTA, and NTA. , Heavy metal ions are sharp
It is difficult to remove because it forms a platinum compound or ammonia complex.
Therefore, even if the pH is adjusted or a large amount of sodium sulfide is added to remove the heavy metal ions, it is not easy to remove the heavy metal ions and almost no Ni ions can be removed. However, according to the present invention, by adding a sulfide to these heavy metal ion-containing waste liquids and holding them at a high temperature and a high pressure for a required time, it is possible to inexpensively remove heavy metal ions containing Ni ions, which could not be removed conventionally. The profit is great because it can be reliably removed.
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成５年７月１９日[Submission date] July 19, 1993
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】発明の詳細な説明[Name of item to be amended] Detailed explanation of the invention
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【発明の詳細な説明】Detailed Description of the Invention
【０００１】[0001]
【産業上の利用分野】本発明は，めっき廃液等の重金属
イオン含有廃液を硫化物の存在下で高温高圧法により効
果的に処理する方法に関する。本発明は，さらに詳しく
は，シアン含有廃液の場合は熱加水分解によるシアン分
解後に残留した重金属イオン，特にニッケルイオンを効
果的に除去し，シアンを含有しない当該廃液の場合，た
とえば，ニッケルイオンとキレート剤等を共に含有し，
重金属イオンの除去が不完全になり易い廃液の場合に
は，重金属イオンを効果的に除去するようにした重金属
イオン含有廃液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 effectively treating heavy metal ion-containing waste liquid such as plating waste liquid in the presence of sulfide by a high temperature and high pressure method. More specifically, the present invention more effectively removes heavy metal ions, especially nickel ions, remaining after the decomposition of cyanide by thermal hydrolysis in the case of a cyanide-containing waste liquid, and in the case of the waste liquid containing no cyanide, for example, nickel ions. Contains chelating agents, etc.,
The present invention relates to a method for treating a heavy metal ion-containing waste liquid that effectively removes heavy metal ions in the case of a waste liquid in which the removal of heavy metal ions is likely to be incomplete.
【０００２】[0002]
【従来の技術】銅，亜鉛，ニッケル等の重金属イオンを
含む高濃度シアン含有廃液（たとえば，めっき液）を熱
加水分解させ，シアンを分解処理することは日本工業新
聞社発行の技術雑誌「ＰＰＭ」の１９９７年，８月号５
８〜６７頁に記載されている通り，既に公知の技術であ
る。上記雑誌の記載事項の要点を記載すると，次の通り
である。熱加水分解処理の原理は，圧力容器内でシアン
化合物を加熱保持しシアンをアンモニア（ＮＨ３）と蟻
酸塩（ＨＣＯＯＫ）に分解し無毒化して排出可能にする
方法であり，反応式として最も単純なシアン化カリウム
に適用した場合は，次の反応式で示される。 ＫＣＮ＋２Ｈ２Ｏ→ＮＨ３＋ＨＣＯＯＫ （１） 鉄（Ｆｅ），亜鉛（Ｚｎ），ニッケル（Ｎｉ）などの金
属シアン錯塩では，反応を進行させるにはアルカリの添
加が必要で，アルカリの存在下で反応が進行しアンモニ
ア，蟻酸塩および金属酸化物と金属水酸化物に加水分解
される。また，Ｋ４Ｆｅ（ＣＮ）６（黄血塩）を使用し
た場合の反応式は（２）式に示されている。 ６Ｋ４Ｆｅ（ＣＮ）６＋１２ＮａＯＨ＋６６Ｈ２Ｏ＋Ｏ
２＝３６ＮＨ３＋２Ｆｅ３Ｏ４＋１２ＨＣＯＯＮａ＋２
４ＨＣＯＯＫ （２） 上記の反応式（２）は，鉄シアン錯塩としての黄血塩が
単独に存在する廃液に関するものであるが，メッキ工場
や鉄鋼の軟窒化処理施設などではカリウムは高価なこと
から，カリウムの代わりにナトリウム（Ｎａ）が使用さ
れる。鉄シアン錯塩としての黄血塩の代わりに，ナトリ
ウムと鉄のシアン錯塩を対象とする場合は，上記反応式
（２）中のＫをＮａに読み替えるだけで良い。2. Description of the Related Art Wastewater containing a high concentration of cyanide (for example, a plating solution) containing heavy metal ions such as copper, zinc and nickel is thermally hydrolyzed to decompose cyanide by the technical magazine "PPM" published by Nihon Kogyo Shimbun. , August 1997, 5
As described on pages 8 to 67, this is a known technique. The main points of the items described in the above journal are as follows. The principle of the thermal hydrolysis treatment is a method in which a cyan compound is heated and held in a pressure vessel and cyan is decomposed into ammonia (NH 3 ) and formate (HCOOK) to be detoxified and discharged, which is the simplest reaction formula. When applied to various potassium cyanides, it is represented by the following reaction formula. KCN + 2H 2 O → NH 3 + HCOOK (1) Metal cyanide complex salts of iron (Fe), zinc (Zn), nickel (Ni), etc. require the addition of alkali in order to proceed the reaction, and react in the presence of alkali. Progresses and is hydrolyzed to ammonia, formate, and metal oxides and metal hydroxides. The reaction formula when K 4 Fe (CN) 6 (yellow blood salt) is used is shown in formula (2). 6K 4 Fe (CN) 6 +12 NaOH + 66H 2 O + O
2 = 36NH 3 + 2Fe 3 O 4 + 12HCOONa + 2
4HCOOK (2) The above reaction formula (2) relates to a waste liquid in which yellow blood salt as an iron cyanide complex salt exists independently, but potassium is expensive in a plating plant or a steel nitrocarburizing facility. , Sodium (Na) is used instead of potassium. When a cyanide complex salt of sodium and iron is used instead of the yellow blood salt as the iron cyanide complex salt, K in the above reaction formula (2) may be replaced by Na.
【０００３】メッキ工場などにおいて，鉄以外に使用さ
れる重金属としてはニッケル（Ｎｉ），亜鉛（Ｚｎ），
銅（Ｃｕ），カドミウム（Ｃｄ），金（Ａｕ），銀（Ａ
ｇ），クロム（Ｃｒ）その他数種が挙げられるが，その
中で代表的にニッケル，亜鉛，銅，カドミウムの４種と
ナトリウムとの，シアン錯塩のそれぞれについての熱加
水分解処理の反応の例を下記（３）〜（６）式に示す。 Ｎａ２Ｎｉ（ＣＮ）４＋２ＮａＯＨ＋８Ｈ２Ｏ ＝４ＮＨ３＋Ｎｉ（ＯＨ）２＋４ＨＣＯＯＮａ （３） Ｎａ２Ｚｎ（ＣＮ）４＋２ＮａＯＨ＋８Ｈ２Ｏ ＝４ＮＨ３＋Ｚｎ（ＯＨ）２＋４ＨＣＯＯＮａ （４） Ｎａ３Ｃｕ（ＣＮ）４＋ＮａＯＨ＋８Ｈ２Ｏ ＝４ＮＨ３＋Ｃｕ（ＯＨ）＋４ＨＣＯＯＮａ （５） Ｎａ２Ｃｄ（ＣＮ）４＋２ＮａＯＨ＋８Ｈ２Ｏ ＝４ＮＨ３＋Ｃｄ（ＯＨ）２＋４ＨＣＯＯＮａ （６） 上記の各反応式を対比すれば明白なように，（３）〜
（６）までのそれぞれの反応式は互いに極めて類似し，
熱加水分解処理による生成物は，アンモニアと，各重金
属の水酸化物および蟻酸塩である。従って，これらの重
金属シアン錯塩を含む混合廃液は，混合によって別の反
応が進行するようなものではなく，単純な反応系の混合
液として取り扱うことができ，上記重金属のそれぞれの
シアン錯塩の熱加水分解にも上記の反応式が適用でき
る。上記（３）〜（６）の反応式では，各重金属の水酸
化物が生成するものとして示されているが，圧力容器内
は高温，高圧下なので，脱水反応によって金属酸化物が
生成される。例として，ニッケル（Ｎｉ）と亜鉛（Ｚ
ｎ）について，熱加水分解により酸化物が生成される場
合の反応式を次に示す。 Ｎａ２Ｎｉ（ＤＮ）４＋２ＮａＯＨ＋７Ｈ２Ｏ ＝４ＮＨ３＋ＮｉＯ＋４ＨＣＯＯＮａ （７） ＮａＺｎ（ＣＮ）４＋２ＮａＯＨ＋７Ｈ２Ｏ ＝４ＮＨ３＋ＺｎＯ＋４ＨＣＯＯＮａ （８） 前記の重金属シアン錯塩の中で，熱加水分解法にとって
処理が困難なのは，銅シアン錯塩である。銅シアン錯塩
が主体となっている廃液の場合は，鉄シアン錯塩の添加
により反応が進行するようにできる。各種のめっき工場
や鉄鋼の軟窒化処理および液体浸炭処理施設からの混合
廃液を処理する場合には，通常廃液中にかなりの量の鉄
シアン錯塩が含まれている状態で供給されるので，鉄シ
アン錯塩を特に添加する必要は殆ど無い。表１は濃厚め
っき廃液について熱加水分解処理を行った場合の実験結
果を示すものである。同表に示す通り，濃厚めっき廃液
を熱加水分解処理した上澄み液（これを熱加水処理液と
いう）について重金属イオン等の含有量を調査した結
果，熱加水分解時に各重金属イオンの大部分は酸化物や
水酸化物となって沈澱除去されている状態が分かる。し
かし，このような熱加水分解処理だけでは，残存重金属
イオン量は表１に示すように，水質規制値を大幅にオー
バーしているのが実情であった。Heavy metals other than iron used in a plating plant or the like include nickel (Ni), zinc (Zn),
Copper (Cu), Cadmium (Cd), Gold (Au), Silver (A
g), chromium (Cr), and several other types, of which representative examples are four types of nickel, zinc, copper, and cadmium, and sodium, and examples of the reaction of thermal hydrolysis treatment of each of the cyan complex salts with sodium. Is shown in the following equations (3) to (6). Na 2 Ni (CN) 4 + 2NaOH + 8H 2 O = 4NH 3 + Ni (OH) 2 + 4HCOONa (3) Na 2 Zn (CN) 4 + 2NaOH + 8H 2 O = 4NH 3 + Zn (OH) 2 + 4HCOONa (4) Na 3 Cu (CN) 4 + NaOH + 8H 2 O = 4NH 3 + Cu (OH) + 4HCOONa (5) Na 2 Cd (CN) 4 + 2NaOH + 8H 2 O = 4NH 3 + Cd (OH) 2 + 4HCOONa (6) As can be seen by comparing the above reaction formulas , (3) ~
The reaction equations up to (6) are very similar to each other,
The products of the thermal hydrolysis treatment are ammonia and hydroxides and formates of each heavy metal. Therefore, the mixed waste liquid containing these heavy metal cyanide complex salts can be handled as a mixed liquid of a simple reaction system, which does not cause another reaction to proceed by mixing, and the thermal hydrolysis of each cyanide complex salt of the above heavy metals can be performed. The above reaction formula can also be applied to decomposition. In the reaction formulas (3) to (6) above, it is shown that hydroxides of each heavy metal are produced, but since the pressure vessel is under high temperature and high pressure, metal oxides are produced by dehydration reaction. . As an example, nickel (Ni) and zinc (Z
Regarding n), the reaction formula when an oxide is produced by thermal hydrolysis is shown below. Among Na 2 Ni (DN) 4 + 2NaOH + 7H 2 O = 4NH 3 + NiO + 4HCOONa (7) NaZn (CN) 4 + 2NaOH + 7H 2 O = 4NH 3 + ZnO + 4HCOONa (8) wherein the heavy metal cyanide complex process that difficult for the thermal hydrolysis method is ， It is a copper cyanide complex salt. In the case of a waste liquid mainly composed of copper cyanide complex salt, the reaction can be promoted by adding iron cyanide complex salt. When treating mixed effluents from various plating plants and steel soft nitriding and liquid carburizing facilities, iron is usually supplied in the state that a considerable amount of iron cyanide complex salt is contained in the effluent. It is almost unnecessary to add a cyan complex salt. Table 1 shows the experimental results when the concentrated plating waste liquid was subjected to the thermal hydrolysis treatment. As shown in the table, as a result of investigating the content of heavy metal ions, etc. in the supernatant liquid obtained by subjecting the concentrated plating waste liquid to the thermal hydrolysis treatment (this is referred to as the thermal hydrolysis treatment liquid), most of the heavy metal ions were oxidized during the thermal hydrolysis. It can be seen that the substances and hydroxides have been removed by precipitation. However, as shown in Table 1, the amount of residual heavy metal ions simply exceeded the water quality regulation value only by such thermal hydrolysis treatment.
【０００４】[0004]
【表１】 [Table 1]
【０００５】また，めっき廃液等の重金属イオン含有廃
液で，上記シアン含有廃液以外の廃液，即ち，シアンを
含有しない重金属イオン含有廃液は，一般にその成分と
して表１の熱加水分解処理液の成分と同様の内容成分あ
るいは表１の原廃液からシアンを除いた成分を内容成分
とする場合が多い。一般的に，このような場合の廃液中
の重金属イオン類の除去方法としては，中和凝集沈澱法
や硫化物沈澱法が考えられる。硫化物沈殿法は臭気の点
で多少問題があるが，硫化物沈澱法の方が中和凝集沈澱
法よりも重金属イオンの除去性が良いといえる。表２
は，重金属イオン含有廃液を常温でその処理液に硫化ナ
トリウムを添加した時の各重金属イオンの残存量を調査
したものである。ｐＨについては７，１０および１３
と，また，硫化ナトリウムの添加量は０ｇ／ｌ，１０ｇ
／ｌおよび１５ｇ／ｌと変化させた条件で実験を行っ
た。[0005] Heavy metal ion-containing waste liquids such as plating waste liquids other than the above-mentioned cyan-containing waste liquids, that is, heavy metal ion-containing waste liquids that do not contain cyan, generally have the same components as those of the thermal hydrolysis treatment liquid of Table 1. In many cases, the same content component or a component obtained by removing cyan from the raw waste liquid in Table 1 is used as the content component. Generally, as a method for removing heavy metal ions in the waste liquid in such a case, a neutralization coagulation precipitation method or a sulfide precipitation method can be considered. Although the sulfide precipitation method has some problems in terms of odor, it can be said that the sulfide precipitation method has better removal of heavy metal ions than the neutralization coagulation precipitation method. Table 2
Is an investigation of the residual amount of each heavy metal ion when sodium sulfide was added to the treated liquid containing heavy metal ion at room temperature. About pH 7, 10 and 13
And, the addition amount of sodium sulfide is 0g / l, 10g
The experiment was carried out under the conditions that the values were changed to 1 / l and 15 g / l.
【０００６】[0006]
【表２】 [Table 2]
【０００７】表２の中央の欄に示すように，硫化ナトリ
ウム添加量を１０ｇ／ｌ（重金属イオン当量の約１０
倍）かつ，ｐＨ１０に調整した場合には，銅，鉄，亜鉛
の金属イオンは表１に記載した水質汚濁防止法の規制値
以内に処理が可能であることが示されている。しかし，
ニッケルイオンの残存量については，このような処理を
しても減少しないことが分かる。ニッケルイオンは水質
汚濁防止法での規制値はないが，神奈県公害防止条例で
は１ｐｐｍと規制されており，この規制値には遠く及ば
ない。即ち，従来技術の常温硫化物沈澱法では重金属イ
オン特にニッケルイオンの残存量が多いことによる微生
物処理の弊害及び硫化ナトリウムを過剰に添加するため
残存硫化物が多くなり，ＣＯＤ対策が必要になるという
弊害（問題点）があった。As shown in the center column of Table 2, the amount of sodium sulfide added was 10 g / l (about 10% of the heavy metal ion equivalent).
It has been shown that when the pH is adjusted to 10 times, the metal ions of copper, iron and zinc can be treated within the regulation values of the Water Pollution Control Law listed in Table 1. However,
It can be seen that the residual amount of nickel ions does not decrease even with such treatment. Nickel ion is not regulated by the Water Pollution Control Law, but it is regulated at 1ppm by the Kanagawa Prefectural Pollution Control Ordinance, which is far below this regulated value. That is, in the conventional room temperature sulfide precipitation method, the adverse effect of microbial treatment due to the large amount of heavy metal ions, especially nickel ions remaining, and the excessive addition of sodium sulfide, the amount of residual sulfide increases and COD countermeasures are required. There was a problem (problem).
【０００８】[0008]
【発明が解決しようとする課題】上記従来技術において
重金属イオンが十分除去できない理由としては，シアン
含有廃液を熱加水分解すると該廃液からアンモニアが発
生し，このアンモニアが重金属イオンと錯体を形成する
こと，または，めっき廃液中に含まれるＥＤＴＡ，ＮＴ
Ａ，グルコン酸ナトリウム，ロッシェル塩等のキレート
剤と重金属イオンが錯体を形成することにより金属水酸
化物等の沈殿物を形成しなくなることによるものと考え
られる。なお，重金属イオン類を完全に除去することは
水質汚濁防止法の観点からも重要なことである。さらに
いえば，通常，重金属イオンの除去の処理後の工程で有
機汚濁物の処理に微生物処理を行っている場合が多く，
重金属イオン特に，Ｎｉイオンが残留すると微生物処理
に悪影響を及ぼすのでＮｉイオンの除去を行うことは重
要であるといえる。本発明は従来の上記課題（問題点）
を解決するようにした重金属イオン含有廃液の処理方法
を提供することを目的とするものである。The reason why heavy metal ions cannot be sufficiently removed in the above-mentioned prior art is that when the cyanide-containing waste liquid is thermally hydrolyzed, ammonia is generated from the waste liquid, and the ammonia forms a complex with the heavy metal ions. , Or EDTA, NT contained in the plating waste liquid
It is considered that this is because a chelating agent such as A, sodium gluconate, and Rochelle salt and a heavy metal ion form a complex, and thus a precipitate such as a metal hydroxide is not formed. Complete removal of heavy metal ions is also important from the viewpoint of the Water Pollution Control Law. Furthermore, usually, in many cases, microbial treatment is used to treat organic pollutants in the step after the treatment for removing heavy metal ions,
It can be said that it is important to remove Ni ions because heavy metal ions, especially Ni ions, adversely affect microbial treatment. The present invention has the above-mentioned conventional problems (problems)
It is an object of the present invention to provide a method for treating a heavy metal ion-containing waste liquid that solves the above problem.
【０００９】[0009]
【課題を解決するための手段】本発明の発明者等は重金
属イオンの除去，特に，ニッケルイオンの除去と硫化ナ
トリウム添加量の低減とを目的として種々の検討，実験
を行った結果，めっき廃液等の重金属イオン含有廃液の
処理方法として，オートクレーブ法（高温，高圧下）と
硫化物沈澱法とを巧みに組み合わせることにより重金属
イオンをほぼ完全に除去する処理方法を見い出した。そ
の処理方法とは，重金属イオン含有廃液に硫化物を添加
し，高温，高圧に所要時間保持するようにした重金属イ
オン含有廃液の処理方法である。また，この処理方法に
は，重金属イオンを含むシアン含有廃液を熱加水分解処
理したのち，該処理廃液に硫化物を添加し，高温，高圧
に所要時間保持するようにしたシアン含有廃液の熱加水
分解後の重金属イオン廃液の処理方法も含まれる。上記
の各処理方法において，高温の条件は１３０〜２５０
℃，また，高圧の条件としては２．７×１０５〜４０×
１０５Ｐａとすることが望ましい。また，硫化物として
は硫化アルカリ金属塩または硫化アンモニウム塩または
硫化水素を用いることが望ましい。また，シアン含有廃
液の熱加水分解後の重金属イオン廃液の処理方法におけ
る硫化物の添加量としては，熱加水分解前のシアン含有
廃液中の重金属イオン（Ｍｅ）の量に対する硫黄イオン
の当量比（Ｓ／Ｍｅ）で，０．６以上の量を選択するこ
とが望ましい。まず，本発明における必須要件の硫化物
について述べる。即ち，後述する表３，表４に示すよう
に，所定の高温，高圧下で，重金属イオン含有廃液に所
要の硫化ナトリウムを添加すると，重金属イオン，特
に，ニッケルイオン残存量が減少し，残留硫化物も少な
くなり，後工程の２次処理にも影響が少なくなることが
確認された。また，添加物として硫化ナトリウムは上記
の通り金属イオン除去の効果が認められるが，さらに，
硫化ナトリウム以外の硫化物について実験したところ，
硫黄を除き硫化カリウム，硫化アンモニウム，硫化水素
等，多くの硫化物で同様の金属イオン除去の効果が認め
られた。これらの硫化物の添加量（Ｓ−−として）は対
金属当量比で０．８の場合でかなり良い効果を示し，
１．０以上で非常に良い結果が得られた。硫化物の添加
量が増えると残留硫化物が増えるので，添加量はなるべ
く対金属当量比で１．０から２．０の範囲が好ましい。
さらに，本発明における高温，高圧条件について述べ
る。後述の表４から次のことがいえる。１０ｇ／ｌの硫
化ナトリウムの添加という同一条件下で実験した場合，
温度，圧力が１００℃，１．０×１０５Ｐａの時にはＮ
ｉは１３３．５というかなりの残存量が認められた。し
かし、１３０℃，２．７×１０５ＰａではＮｉは４．０
という低い濃度まで下がり，他の金属イオンはほとんど
除去できた。さらに，２１０℃，１９×１０５Ｐａとし
た時は，ニッケル残存量が０．５ｐｐｍとなり，これは
神奈川県の規制値以下となった。即ち，一般に反応器を
２５０℃以上に上げるのは耐圧力容器に関する法規制上
困難なため，硫化物の添加時の温度は１３０℃〜２５０
℃が望ましい。従って，圧力は２．７×１０５Ｐａ〜４
０×１０５Ｐａが望ましい。硫化物添加時の反応時間は
上記温度，圧力範囲で少なくとも５分間は必要でありそ
れ以下では残留Ｎｉイオン量が多くなる傾向がある。さ
らに，本発明における重金属イオン含有廃液のＰＨ条件
について述べると次の通りである。即ち，ＰＨ条件は除
去したい金属イオンによって異なるが，本発明の場合に
はＰＨ７以上であることが好ましく，より好ましいＰＨ
条件は，ＰＨ９以上である。ＰＨ７未満の場合は重金属
イオン除去効率が低下する。The inventors of the present invention have conducted various studies and experiments for the purpose of removing heavy metal ions, in particular, removing nickel ions and reducing the amount of sodium sulfide added. As a method for treating a waste liquid containing heavy metal ions such as the above, we have found a method for removing heavy metal ions almost completely by skillfully combining the autoclave method (under high temperature and high pressure) and the sulfide precipitation method. The treatment method is a treatment method of a heavy metal ion-containing waste liquid in which a sulfide is added to the heavy metal ion-containing waste liquid and is kept at high temperature and high pressure for a required time. In this treatment method, a cyanide-containing waste liquid containing heavy metal ions is subjected to a thermal hydrolysis treatment, and then a sulfide is added to the treated waste liquid so that the cyanide-containing waste liquid is kept at high temperature and high pressure for a required time. A method of treating heavy metal ion waste liquid after decomposition is also included. In each of the above processing methods, the high temperature condition is 130 to 250.
℃, high pressure conditions of 2.7 × 10 5 to 40 ×
It is desirable to set it to 10 5 Pa. As the sulfide, it is desirable to use alkali metal sulfide, ammonium sulfide, or hydrogen sulfide. In addition, as the amount of sulfide added in the method for treating heavy metal ion waste liquid after thermal hydrolysis of cyanide-containing waste liquid, the equivalent ratio of sulfur ions to the amount of heavy metal ions (Me) in the cyanide-containing waste liquid before thermal hydrolysis ( In S / Me), it is desirable to select an amount of 0.6 or more. First, the essential sulfide in the present invention will be described. That is, as shown in Tables 3 and 4 described later, when the required sodium sulfide is added to the heavy metal ion-containing waste liquid at a predetermined high temperature and high pressure, the residual amount of heavy metal ions, particularly nickel ions, is reduced and It was also confirmed that the amount of waste was reduced and the secondary treatment in the post process was less affected. Also, sodium sulfide as an additive has the effect of removing metal ions as described above.
When we experimented with sulfides other than sodium sulfide,
Except for sulfur, many sulfides such as potassium sulfide, ammonium sulfide, hydrogen sulfide, etc. were found to have the same effect of removing metal ions. The amount of the sulfide (S - as) represents a fairly good effect in the case of 0.8-to-metal equivalent ratio,
Very good results were obtained at 1.0 or higher. Since the residual sulfide increases as the added amount of sulfide increases, the added amount is preferably in the range of 1.0 to 2.0 in terms of metal equivalent ratio.
Further, the high temperature and high pressure conditions in the present invention will be described. The following can be said from Table 4 below. When tested under the same conditions with the addition of 10 g / l sodium sulfide,
N when temperature and pressure are 100 ° C and 1.0 × 10 5 Pa
As for i, a considerable residual amount of 133.5 was recognized. However, Ni was 4.0 at 130 ° C. and 2.7 × 10 5 Pa.
The concentration was lowered to such a low concentration, and almost all other metal ions could be removed. Further, when the temperature was 210 ° C. and 19 × 10 5 Pa, the residual nickel amount was 0.5 ppm, which was below the limit value of Kanagawa prefecture. That is, it is generally difficult to raise the temperature of the reactor to 250 ° C. or higher due to legal regulations regarding the pressure-resistant container, so the temperature during the addition of the sulfide is 130 ° C.
℃ is desirable. Therefore, the pressure is 2.7 × 10 5 Pa to 4
0 × 10 5 Pa is desirable. The reaction time at the time of adding sulfides is required to be at least 5 minutes within the above temperature and pressure ranges, and the amount of residual Ni ions tends to increase below that. Further, the PH conditions of the waste liquid containing heavy metal ions in the present invention will be described as follows. That is, although the PH condition varies depending on the metal ion to be removed, in the case of the present invention, it is preferably PH7 or more, and more preferable PH
The condition is PH9 or higher. If it is less than PH7, the efficiency of removing heavy metal ions decreases.
【００１０】[0010]
【作用】鉄，銅，亜鉛，ニッケルの各イオンを含むシア
ン含有廃液の熱加水分解反応は，（９）〜（１３）式に
示す反応をするものと考えられる。また，鉄以外の金属
イオンは水酸化物だけでなく一部酸化物も形成している
と思われる。Ｆｅイオンはアンモニア錯体を作らず，Ｆ
ｅ３Ｏ４の形で殆ど沈澱するので除去は容易である。 ＮａＣＮ＋２Ｈ２Ｏ＝ＮＨ３＋ＨＣＯＯＮａ・・・・・
・・・（９） Ｎａ４Ｆｅ（ＣＮ）６＋２ＮａＯＨ＋１１Ｈ２Ｏ＋１／
６Ｏ２＝６ＮＨ３＋６ＨＣＯＯＮａ＋１／３Ｆｅ３Ｏ４
・・（１０） Ｎａ３Ｃｕ（ＣＮ）４＋ＮａＯＨ＋８Ｈ２Ｏ＝４ＮＨ３
＋Ｃｕ（ＯＨ）＋４ＨＣＯＯＮａ・・・・（１１） Ｎａ２Ｚｎ（ＣＮ）４＋２ＮａＯＨ＋８Ｈ２Ｏ＝４ＮＨ
３＋Ｚｎ（ＯＨ）２＋４ＨＣＯＯＮａ・・・（１２） Ｎａ２Ｎｉ（ＣＮ）４＋２ＮａＯＨ＋８Ｈ２Ｏ＝４ＮＨ
３＋Ｎｉ（ＯＨ）２＋４ＨＣＯＯＮａ・・・（１３）The thermal hydrolysis reaction of the cyanide-containing waste liquid containing iron, copper, zinc, and nickel ions is considered to be the reaction represented by the equations (9) to (13). Moreover, it is considered that metal ions other than iron form not only hydroxides but also some oxides. Fe ions do not form an ammonia complex, and F
It is easy to remove as it mostly precipitates in the form of e 3 O 4 . NaCN + 2H 2 O = NH 3 + HCOONa ·····
··· (9) Na 4 Fe ( CN) 6 + 2NaOH + 11H 2 O + 1 /
6O 2 = 6NH 3 + 6HCOONa + 1 / 3Fe 3 O 4
·· (10) Na 3 Cu ( CN) 4 + NaOH + 8H 2 O = 4NH 3
+ Cu (OH) + 4HCOONa ···· (11) Na 2 Zn (CN) 4 + 2NaOH + 8H 2 O = 4NH
3 + Zn (OH) 2 + 4HCOONa ... (12) Na 2 Ni (CN) 4 + 2NaOH + 8H 2 O = 4NH
3 + Ni (OH) 2 + 4HCOONa ... (13)
【００１１】一方，他の金属イオンは熱加水分解で発生
したアンモニアと（１４）〜（１５）式のようなアンモ
ニア錯体を形成する。 Ｃｕ＋４ＮＨ３＝〔Ｃｕ（ＮＨ３）４〕２＋・・・・・
・・・・・・・（１４） Ｚｎ＋４ＮＨ３＝〔Ｚｎ（ＮＨ３）４〕２＋・・・・・
・・・・・（１５） Ｎｉ＋６ＮＨ３＝〔Ｎｉ（ＮＨ３）６〕２＋・・・・・
・・・・・・（１６） 高温，高圧下で硫化ナトリウムを添加すると 〔Ｃｕ（ＮＨ３）４〕２＋＋Ｓ２−＝ＣｕＳ↓＋４ＮＨ
３・・・・・・・（１７） 〔Ｚｎ（ＮＨ３）４〕２＋＋Ｓ２−＝ＺｎＳ↓＋４ＮＨ
３・・・・・・・・（１８） 〔Ｎｉ（ＮＨ３）６〕２＋＋Ｓ２−＝ＮｉＳ↓＋６ＮＨ
３・・・・・・・・・（１９） となり，金属イオン類は硫化物の沈澱を作り容易に除去
できる。めっき廃液にはグルコン酸塩，ロッシェル塩，
ＥＤＴＡ，ＮＴＡ等のキレート剤が入っており，これら
と銅，亜鉛，ニッケル等の各イオンが安定なキレート化
合物を形成している。そのため常温においては硫化物を
添加しても重金属イオンは除去しにくい。しかし，硫化
物を添加して熱加水分解すれば重金属除去効率は大幅に
向上し，さらに，シアン分解後，高温，高圧下で硫化物
を添加すれば表３のように，より効果的に重金属は除去
されている。On the other hand, other metal ions form an ammonia complex represented by the formulas (14) to (15) with ammonia generated by thermal hydrolysis. Cu + 4NH 3 = [Cu (NH 3) 4] 2+ -----
······· (14) Zn + 4NH 3 = [Zn (NH 3) 4] 2+ -----
(15) Ni + 6NH 3 = [Ni (NH 3 ) 6 ] 2+
(16) When sodium sulfide is added at high temperature and high pressure, [Cu (NH 3 ) 4 ] 2+ + S 2 − = CuS ↓ + 4NH
3 ....... (17) [Zn (NH 3) 4] 2+ + S 2- = ZnS ↓ + 4NH
3 ... (18) [Ni (NH 3 ) 6 ] 2+ + S 2 − = NiS ↓ + 6NH
3 ... (19), the metal ions form a sulfide precipitate and can be easily removed. For plating waste liquid, gluconate, Rochelle salt,
It contains a chelating agent such as EDTA and NTA, and these ions such as copper, zinc and nickel form a stable chelating compound. Therefore, at room temperature, it is difficult to remove heavy metal ions even if sulfide is added. However, if sulfides are added and subjected to thermal hydrolysis, the removal efficiency of heavy metals is significantly improved. Furthermore, if sulfides are added at high temperature and high pressure after the decomposition of cyanide, as shown in Table 3, it is more effective. Have been removed.
【００１２】比較例１，２，３ 全シアン１６４００ｐｐｍ，Ｆｅ４８０ｐｐｍ，Ｃｕ３
９００ｐｐｍ，Ｚｎ１６００ｐｐｍおよびＮｉ１５００
ｐｐｍ，その他若干の重金属イオンを含む混合めっき老
廃液をオートクレーブに入れ，比較例１，２及び３とし
て熱加水分解前に対金属当量比で１．０，１．２および
２．０の硫化ナトリウムを添加し，２１０℃，１９×１
０５Ｐａ（１９×１０５Ｐａは２１０℃の水の飽和蒸気
圧を示す）６時間熱加水分解させ，処理液を濾紙（ＮＯ
５Ｃ）でろ過し重金属イオン類の分析をした結果を表３
の左欄に示す。この結果，表３の左欄に示すように，対
金属当量比で１．０の硫化ナトリウムを入れても重金属
イオン類はかなり残り，さらに硫化ナトリウムの添加量
を増やし，対金属当量比で２．０入れても，Ｎｉイオン
は１．０ｐｐｍ以下にはならないことが確認された。Comparative Examples 1, 2, 3 Total cyan 16400ppm, Fe 480ppm, Cu3
900ppm, Zn1600ppm and Ni1500
A mixed plating waste liquid containing ppm and some other heavy metal ions was put into an autoclave, and as Comparative Examples 1, 2, and 3, sodium sulfide having a metal equivalent ratio of 1.0, 1.2, and 2.0 before thermal hydrolysis. 210 ℃, 19 × 1
It is hydrolyzed for 6 hours at 0 5 Pa (19 × 10 5 Pa indicates a saturated vapor pressure of water at 210 ° C.), and the treatment liquid is filtered (NO).
5C) and the results of heavy metal ion analysis are shown in Table 3.
Are shown in the left column. As a result, as shown in the left column of Table 3, even if sodium sulfide with a metal equivalent ratio of 1.0 was added, heavy metal ions remained considerably, and the amount of sodium sulfide added was further increased to obtain a metal equivalent ratio of 2 It was confirmed that the Ni ion content does not become 1.0 ppm or less even if 0.0 is added.
【００１３】比較例４ 次に，上記のめっき廃液を硫化ナトリウムを添加せず，
同条件で熱加水分解させ，シアン分解後，２１０℃，１
９×１０５Ｐａ，の高温，高圧下で原廃液の対金属当量
比で０．５の硫化ナトリウムを入れ５分間保持し冷却し
た。この処理液を濾紙（ＮＯ５Ｃ）でろ過し，重金属イ
オン類の分析を行った結果を表３の右欄に示す。この場
合，対金属当量比で０．５で各重金属イオンは若干では
あるがさがるという結果が得られた。Comparative Example 4 Next, the above plating waste liquid was added to the above without adding sodium sulfide,
Thermally hydrolyzed under the same conditions, after cyanide decomposition, 210 ℃, 1
Under a high temperature and a high pressure of 9 × 10 5 Pa, sodium sulfide having a metal equivalent ratio of 0.5 to the raw waste liquid was added, and the mixture was kept for 5 minutes and cooled. The treatment liquid is filtered through a filter paper (NO5C) and the heavy metal ions are analyzed. The results are shown in the right column of Table 3. In this case, the result was obtained in which the weight ratio of metal to metal was 0.5, but the amount of each heavy metal ion slightly decreased.
【００１４】比較例５ また，この時の温度による効果を調べるために，上記の
比較例４と同様な処理条件で熱加水分解後，反応器の温
度，圧力を１００℃，１．０×１０５Ｐａで硫化ナトリ
ウムを対金属当量比で１．０添加し５分間保持後冷却
し，ろ過水の金属イオン濃度を分析した結果を表４に示
す。この場合，同表に示すように，Ｎｉを除く各重金属
イオンは低位までさがることが示されている。Comparative Example 5 Further, in order to investigate the effect of temperature at this time, after thermal hydrolysis under the same processing conditions as in Comparative Example 4, the temperature and pressure of the reactor were 100 ° C. and 1.0 × 10 6. Table 4 shows the results of analyzing the metal ion concentration of filtered water by adding sodium sulfide 1.0 at 5 Pa in a metal equivalent ratio of 1.0, holding for 5 minutes and then cooling. In this case, as shown in the same table, it is shown that each heavy metal ion except Ni is lowered to a low level.
【００１５】[0015]
【実施例】 実施例１，２ 本発明の実施例１及び実施例２の場合として，上記のめ
っき廃液を硫化ナトリウムを添加せず，同条件で熱加水
分解させ，シアン分解後，２１０℃，１９×１０５Ｐ
ａ，の高温，高圧下で原廃液の対金属当量比で０．８及
び１．０の硫化ナトリウムを入れ５分間保持し冷却し
た。この処理液を濾紙（ＮＯ５Ｃ）でろ過し，重金属イ
オン類の分析を行った結果を表３の右欄に示す。この場
合，実施例１の場合でもＮｉを含む各重金属イオンは低
位までさがり，そして，実施例２の場合には，Ｎｉイオ
ンでも１．０ｐｐｍ以下の値にまでさがるという，良い
結果が得られた。 実施例２．３ ，実施例２，３の各場合における温度による効果を調べ
るために，上記の実施例１，２と同様な処理条件で熱加
水分解後，反応器の温度，圧力を１３０℃，２．７×１
０５Ｐａ（実施例３）及び２１０℃，１９×１０５Ｐａ
（実施例２）で硫化ナトリウムを対金属当量比で１．０
添加し５分間保持後冷却し，ろ過水の金属イオン濃度を
分析した結果を表４に示す。同表に示すように，実施例
３の場合である１３０℃，２．７×１０５Ｐａでの硫化
ナトリウムの添加でかなりの重金属除去作用が認めら
れ，さらに，実施例２の場合である２１０℃，１９×１
０５Ｐａで硫化ナトリウムの添加では問題のＮｉが０．
５ｐｐｍ迄低下している様子が分かる。[Examples] Examples 1 and 2 In the case of Examples 1 and 2 of the present invention, the above plating waste liquid was hydrolyzed under the same conditions without adding sodium sulfide, and after the cyan decomposition, at 210 ° C, 19 x 10 5 P
Under a high temperature and high pressure of a, sodium sulfide having a metal equivalent ratio of 0.8 and 1.0 in the raw waste liquid was charged and held for 5 minutes to cool. The treatment liquid is filtered through a filter paper (NO5C) and the heavy metal ions are analyzed. The results are shown in the right column of Table 3. In this case, good results were obtained in which even in the case of Example 1, each heavy metal ion containing Ni went down to a low level, and in the case of Example 2, the Ni ion also went down to a value of 1.0 ppm or less. . In order to investigate the effect of temperature in each of Examples 2.3 and 2 and 3, after thermal hydrolysis under the same treatment conditions as in Examples 1 and 2, the reactor temperature and pressure were set to 130 ° C. , 2.7 × 1
0 5 Pa (Example 3) and 210 ° C., 19 × 10 5 Pa
In Example 2, sodium sulfide was 1.0 in terms of metal equivalent ratio.
Table 4 shows the results of analyzing the metal ion concentration of the filtered water after adding and holding for 5 minutes and cooling. As shown in the table, a considerable heavy metal removing action was recognized by the addition of sodium sulfide at 130 ° C. and 2.7 × 10 5 Pa, which is the case of Example 3, and 210 of Example 2. ℃, 19 × 1
At 0 5 Pa, the addition of sodium sulfide resulted in the problematic Ni.
It can be seen that it has dropped to 5 ppm.
【００１６】[0016]
【表３】 [Table 3]
【００１７】[0017]
【表４】 上記の実施例のものは，重金属イオンを含む混合めっき
老廃液の熱加水分解後のシアン廃液の後処理としての重
金属イオンの除去処理について述べたが，このような熱
加水分解後のシアン廃液からの重金属イオンの除去に限
らず，各種の重金属イオン含有液，特に，Ｎｉとキレー
ト剤を含有する重金属イオン含有液からの重金属イオン
の除去に有効な処理方法であることは勿論である。[Table 4] In the above-mentioned embodiment, the heavy metal ion removal treatment as the post-treatment of the cyan waste liquid after the thermal hydrolysis of the mixed plating waste liquid containing the heavy metal ions is described. It is needless to say that the treatment method is not limited to the removal of heavy metal ions, and is effective for removal of heavy metal ions from various heavy metal ion-containing liquids, particularly heavy metal ion-containing liquids containing Ni and a chelating agent.
【００１８】[0018]
【表５】 実施例４〜１１及び比較例６ 重金属イオンを含む混合めっき老廃液についてＮａＨＳ
の２段添加を行い，熱加水分解処理をした前後の結果及
び比較例としてＮａＨＳの初期添加結果を表５に示し
た。なお，Ａ，Ｂ，Ｃ，Ｄについては廃液中の全金属イ
オンモル数と同モルになるようにＮａＨＳを添加処理し
た。Ｅについては，廃液中の全金属イオンモル数の１．
３倍になるように硫化物を添加して処理した。熱加水分
解処理条件は，めっき廃液６ｍ３にＮａＯＨを加えてｐ
Ｈ１３．５以上にして１２ｍ３のオートクレーブに入
れ，これに廃液中の重金属イオンに対し，各条件の硫化
物を添加した。１段添加の場合は２１０℃，１３時間
で，また，２段添加の場合には１８５℃，６時間（１段
添加後４時間，２段添加後２時間処理）で行った。その
結果，ＮａＨＳなどの硫化物を２段添加することによ
り，シアンの分解速度が促進され，低温，低圧，短縮化
が計られた。また，重金属イオンも水質汚濁防止法の規
制値を下回っていることが確認された。[Table 5] Examples 4 to 11 and Comparative Example 6 Mixed plating waste liquid containing heavy metal ions NaHS
Table 5 shows the results before and after the two-stage addition of and the thermal hydrolysis treatment and the initial addition results of NaHS as a comparative example. For A, B, C and D, NaHS was added so that the number of moles of all metal ions in the waste liquid was the same. For E, the total number of moles of metal ions in the waste liquid is 1.
It was treated by adding sulfide so as to be tripled. Pyrohydrolysis process conditions, the addition of NaOH to the plating waste 6 m 3 p
After H13.5 or more, it was put into a 12 m 3 autoclave, and sulfide under each condition was added to the heavy metal ions in the waste liquid. The addition was carried out at 210 ° C. for 13 hours in the case of one-stage addition, and at 185 ° C. for 6 hours in the case of two-stage addition (4 hours after the addition of one step and 2 hours after the addition of two steps). As a result, by adding sulfides such as NaHS in two stages, the decomposition rate of cyan was accelerated, and low temperature, low pressure, and shortening were achieved. It was also confirmed that heavy metal ions were below the regulation value of the Water Pollution Control Law.
【００１９】[0019]
【発明の効果】重金属イオン含有めっき廃液等には，グ
ルコン酸塩，ロッシェル塩，ＥＤＴＡ，ＮＴＡ等のキレ
ート剤が多量に含まれている場合が多く，これらのキレ
ート剤及びアンモニアにより，重金属イオン類がキレー
ト化合物やアンモニア錯体を作るため除去されにくい。
それ故，重金属イオン類除去のため，ｐＨの調整や硫化
ナトリウムの多量の添加をしても，重金属イオン類の除
去は容易でなく，Ｎｉイオンについては殆ど除去できな
かった。しかし，本発明により，これらの重金属イオン
含有廃液に硫化物を添加し，高温，高圧に所要時間保持
するという処理を行うことによって，従来は除去できな
かったＮｉイオンを含む重金属イオン類を安価，確実に
除去できるので，その実利は大である。EFFECTS OF THE INVENTION Heavy metal ion-containing plating waste liquids often contain a large amount of chelating agents such as gluconate, Rochelle salt, EDTA, and NTA, and heavy metal ions are contained by these chelating agents and ammonia. Is not easily removed because it forms a chelate compound or ammonia complex.
Therefore, even if the pH is adjusted or a large amount of sodium sulfide is added to remove the heavy metal ions, it is not easy to remove the heavy metal ions and almost no Ni ions can be removed. However, according to the present invention, by adding a sulfide to these heavy metal ion-containing waste liquids and holding them at a high temperature and a high pressure for a required time, it is possible to inexpensively remove heavy metal ions containing Ni ions, which could not be removed conventionally. The profit is great because it can be reliably removed.
Claims (5)
し，高温，高圧に所要時間保持することを特徴とする重
金属イオン含有廃液の処理方法。1. A method for treating a heavy metal ion-containing waste liquid, which comprises adding a sulfide to the heavy metal ion-containing waste liquid and holding the sulfide at a high temperature and a high pressure for a required time.
加水分解処理したのち，該処理廃液に硫化物を添加し，
高温，高圧に所要時間保持することを特徴とするシアン
含有廃液の熱加水分解後の重金属イオン含有廃液の処理
方法。2. A cyan-containing waste liquid containing heavy metal ions is subjected to a thermal hydrolysis treatment, and then a sulfide is added to the treated waste liquid,
A method for treating a heavy metal ion-containing waste liquid after thermal hydrolysis of a cyanide-containing waste liquid, characterized by holding at high temperature and high pressure for a required time.
高圧の条件としては２．７×１０5〜４０×１０5Ｐａと
するようにした請求項１または２のいずれかに記載の重
金属イオン含有廃液の処理方法。3. The high temperature condition is 130 to 250 ° C., and
The method for treating a heavy metal ion-containing waste liquid according to claim 1 or 2, wherein the high-pressure condition is 2.7 x 10 5 to 40 x 10 5 Pa.
は硫化アンモニウム塩または硫化水素を用いるようにし
た請求項１または２のいずれかに記載の重金属イオン含
有廃液の処理方法。4. The method for treating a heavy metal ion-containing waste liquid according to claim 1, wherein an alkali metal sulfide, an ammonium sulfide, or hydrogen sulfide is used as the sulfide.
のシアン含有廃液中の重金属イオン（Ｍｅ）の量に対す
る硫黄イオンの当量比（Ｓ／Ｍｅ）で，０．６以上の量
を選択するようにした請求項２に記載のシアン含有廃液
の熱加水分解後の重金属イオン含有廃液の処理方法。5. The amount of sulfide added is an equivalent ratio (S / Me) of sulfur ions to the amount of heavy metal ions (Me) in the cyanide-containing waste liquid before thermal hydrolysis and is 0.6 or more. The method for treating a heavy metal ion-containing waste liquid after thermal hydrolysis of a cyanide-containing waste liquid according to claim 2, which is selected.
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|---|---|---|---|
| JP14891292A JP3350820B2 (en) | 1992-05-18 | 1992-05-18 | Treatment method for waste liquid containing heavy metal ions |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14891292A JP3350820B2 (en) | 1992-05-18 | 1992-05-18 | Treatment method for waste liquid containing heavy metal ions |
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| JP3350820B2 JP3350820B2 (en) | 2002-11-25 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07214074A (en) * | 1994-02-04 | 1995-08-15 | Ind Technol Res Inst | Method of recovering metal from waste liquid containing cyanided metal |
| CN102491477A (en) * | 2011-11-25 | 2012-06-13 | 中南大学 | Method and device for removing mercury from high concentration acid |
| CN104261526A (en) * | 2014-09-17 | 2015-01-07 | 哈尔滨工业大学深圳研究生院 | Treatment method of heavy metal wastewater |
| CN105668766A (en) * | 2016-04-11 | 2016-06-15 | 徐州工程学院 | Device and method for removing heavy metal ions in industrial sewage |
| CN110055416A (en) * | 2019-05-24 | 2019-07-26 | 吉首大学 | A kind of method of zinc hydrometallurgy industrial sulphuric acid hydrochloric acid separating and recovering |
-
1992
- 1992-05-18 JP JP14891292A patent/JP3350820B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07214074A (en) * | 1994-02-04 | 1995-08-15 | Ind Technol Res Inst | Method of recovering metal from waste liquid containing cyanided metal |
| CN102491477A (en) * | 2011-11-25 | 2012-06-13 | 中南大学 | Method and device for removing mercury from high concentration acid |
| CN104261526A (en) * | 2014-09-17 | 2015-01-07 | 哈尔滨工业大学深圳研究生院 | Treatment method of heavy metal wastewater |
| CN105668766A (en) * | 2016-04-11 | 2016-06-15 | 徐州工程学院 | Device and method for removing heavy metal ions in industrial sewage |
| CN110055416A (en) * | 2019-05-24 | 2019-07-26 | 吉首大学 | A kind of method of zinc hydrometallurgy industrial sulphuric acid hydrochloric acid separating and recovering |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3350820B2 (en) | 2002-11-25 |
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