JPS6235837B2 - - Google Patents
Info
- Publication number
- JPS6235837B2 JPS6235837B2 JP58073075A JP7307583A JPS6235837B2 JP S6235837 B2 JPS6235837 B2 JP S6235837B2 JP 58073075 A JP58073075 A JP 58073075A JP 7307583 A JP7307583 A JP 7307583A JP S6235837 B2 JPS6235837 B2 JP S6235837B2
- Authority
- JP
- Japan
- Prior art keywords
- edta
- waste liquid
- ions
- acid
- iron
- 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.)
- Expired
Links
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 claims description 52
- 239000007788 liquid Substances 0.000 claims description 50
- 239000013078 crystal Substances 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 24
- 239000002699 waste material Substances 0.000 claims description 22
- 150000002500 ions Chemical class 0.000 claims description 21
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 20
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 20
- 229910001385 heavy metal Inorganic materials 0.000 claims description 14
- 239000003513 alkali Substances 0.000 claims description 11
- 229910052742 iron Inorganic materials 0.000 claims description 11
- 238000004140 cleaning Methods 0.000 claims description 10
- 239000000126 substance Substances 0.000 claims description 10
- 238000001914 filtration Methods 0.000 claims description 9
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 claims description 8
- 229910001431 copper ion Inorganic materials 0.000 claims description 8
- 239000002253 acid Substances 0.000 claims description 7
- 239000000706 filtrate Substances 0.000 claims description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 6
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 4
- 239000010419 fine particle Substances 0.000 claims description 3
- 239000003112 inhibitor Substances 0.000 claims description 3
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 claims description 2
- 229910001424 calcium ion Inorganic materials 0.000 claims description 2
- -1 iron ions Chemical class 0.000 claims 2
- 230000001590 oxidative effect Effects 0.000 claims 1
- 238000000926 separation method Methods 0.000 description 19
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 11
- 238000012546 transfer Methods 0.000 description 9
- 239000011859 microparticle Substances 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 5
- 239000002244 precipitate Substances 0.000 description 5
- 238000003756 stirring Methods 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 238000002425 crystallisation Methods 0.000 description 4
- 230000008025 crystallization Effects 0.000 description 4
- 235000011121 sodium hydroxide Nutrition 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- VEQPNABPJHWNSG-UHFFFAOYSA-N Nickel(2+) Chemical compound [Ni+2] VEQPNABPJHWNSG-UHFFFAOYSA-N 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910001453 nickel ion Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000009287 sand filtration Methods 0.000 description 2
- 229910052979 sodium sulfide Inorganic materials 0.000 description 2
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000006228 supernatant Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 208000005156 Dehydration Diseases 0.000 description 1
- 230000000274 adsorptive effect Effects 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- UYJXRRSPUVSSMN-UHFFFAOYSA-P ammonium sulfide Chemical compound [NH4+].[NH4+].[S-2] UYJXRRSPUVSSMN-UHFFFAOYSA-P 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000013522 chelant Substances 0.000 description 1
- 239000012459 cleaning agent Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- OMZSGWSJDCOLKM-UHFFFAOYSA-N copper(II) sulfide Chemical compound [S-2].[Cu+2] OMZSGWSJDCOLKM-UHFFFAOYSA-N 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 235000014413 iron hydroxide Nutrition 0.000 description 1
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 235000011118 potassium hydroxide Nutrition 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 150000004763 sulfides Chemical class 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/36—Regeneration of waste pickling liquors
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Removal Of Specific Substances (AREA)
Description
本発明は化学洗浄廃液の処理方法、特にエチレ
ンジアミン四酢酸（以下、「EDTA」と略す）と
結合した重金属イオンを含む化学洗浄廃液の処理
方法に関するものである。
従来EDTAはキレート洗浄剤としてボイラ、熱
交換器、配管等のスケール除去に広く用いられて
いる。この洗浄廃液中には洗浄過程でEDTAと結
合した多重の重金属イオンと高濃度のCODを含
み、従来から効率的な廃液処理方法の開発が求め
られていた。
本発明は、鋭意研究の結果、廃液中からEDTA
を回収して再利用を図ることを可能にしたもので
ある。
即ち、本発明はEDTAと結合した重金属イオン
を含む化学洗浄廃液の処理方法において、該廃液
にアルカリを添加してPH10以上で重金属イオンを
沈殿分離させる第１工程、前記第１工程の分離液
を活性炭ろ過層を通すことにより該分離液中の微
粒子やインヒビターを除去する第２工程、および
前記第２工程のろ過液に酸を添加して、PH1.3〜
1.8の範囲にてEDTAの結晶を生成させ、該結晶
を分離回収する第３工程とからなることを特徴と
するEDTAを含む化学洗浄廃液の処理方法であ
る。
以下に本発明の処理方法について詳述する。
本発明の処理方法は、まず、廃液にアルカリを
添加してEDTAとキレートしている重金属イオン
をEDTAから分離させる。該分離工程において
は、苛性ソーダなどのアルカリ剤を注入して液の
PHを10以上にする必要があるが銅イオン、ニツケ
ルイオンを含有する場合にはPH12以上、望ましく
はPH12.5にする。また鉄（）イオンを含有する
場合は空気などで曝気することにより酸化し鉄
（）イオンにすることが望ましい。これは鉄
（）イオンであればPH12.5以上にすることを要
するが、鉄（）イオンにしておけばPH12で良
く、つまり加えるアルカリ剤の量が少なくて済み
経済的であるからである。
なお、鉄（）イオンを酸化する手段はどのよ
うな方法でも適用可能（例えば酸化剤を用いる
等）であるが、空気を用いて曝気するのが簡便で
あり経済的である。
廃液がアンモニアを含む場合には、銅イオンや
ニツケルイオンはPH12.5でも解離できない。これ
を解離させるにはPH14以上にしなければならな
い。従つて銅イオンについてはアルカリとして硫
化ソーダ、硫化アンモンなどの硫化アルカリを銅
イオンの1.0〜1.1当量加えることにより硫化銅と
して分離することができる。この場合の液のPHは
アルカリ性であればよいから使用するアルカリ剤
の量が節約でき経済的である。
なお、アルカリの種類として苛性ソーダ、硫化
アルカリの他に消石灰、苛性カリなどでも使用可
能である。
また、重金属の分離において、そのまま静置す
ることで分離するが、高分子凝集剤を添加するこ
とにより分離の速度を増し、かつ沈殿物の容積を
縮小する効果が有り、有効である。
次に、第１工程で重金属イオンを沈殿分離させ
た分離液中の微小粒子を活性炭ろ過層を通すこと
によつて除去する。該分離液中の微小粒子はコロ
イド状の水酸化鉄を主体とするものであるが、静
置だけでは充分に分離することができない粒子で
ある。この微小粒子は、次の第３工程で生成する
EDTAの結晶に付着し著しく汚染をきたすもので
ある。また該沈殿物は脱水処理を行い、この脱離
液からもEDTAを分離するものであるが、この場
合にも該脱離液には微小粒子が分離上澄液よりも
多く含まれる。従つて該微小粒子を取り除く必要
がある。
そのための除去処理方法として活性炭を用いて
ろ過する方法が最も効果が有り、微小粒子は完全
に除去される。同じろ過法として砂ろ過法も有る
が、該微小粒子を完全に取り除くことは実用上か
なり困難であり、フイルターによる方法でも１μ
ｍ以下のものを用いることにより完全に除去でき
るが、その捕捉量が少なく実用性に乏しい。従つ
て活性炭を用いてろ過するのが最も良い方法であ
る。
さらに、活性炭は吸着性が大きく、そのため洗
浄液に含まれている高分子量のインヒビターなど
も取り除く作用が有り、両方の効果を担うことに
なる。
次に、第２工程でろ過したろ過液に酸を添加し
てEDTAの結晶を生成させ該結晶を分離回収す
る。該EDTAの結晶生成時の液のPH域はEDTAの
濃度によつて幅が認められるが、PH4.0〜1.0であ
る。
ここでEDTAの結晶化とPHの関係を仔細に調べ
た結果を第１図に示す。これはEDTAの４％水溶
液をそれぞれのPHにて結晶化させ、沈殿分離後の
ろ液中に残留するEDTAの量を経時的に各PHで調
べたものである。
この図からPH1.3以下あるいはPH1.8以上では結
晶化の速度が次第に遅くなり、かつEDTAの溶解
度も大きくなること、従つてPH域は1.3〜1.8の範
囲が最も良い条件であることが判る。
また、該ろ過液からのEDTAの分離回収を連続
で行う場合に、結晶の生成反応槽を２槽以上連結
して直列で行う方法が、同じ滞留時間の単槽で行
うよりも有利である。これは単槽で連続して行う
と、ある確率でシヨートパスが起こり未反応の
EDTAが流出してしまうが、これを２槽以上の直
列にして行うとシヨートパスの確率が非常に小さ
くなり、ほぼEDTAの溶解度まで、つまり完全に
結晶化させることができるようになり、従つて回
収率の向上につながるからである。
さらに、結晶化させる条件のうち液の撹拌につ
いては、撹拌周速は1.2ｍ／sec程度で充分である
が、この速度が極端に速くなると結晶が細分化す
るか又は結晶核の発生量が多くなる。そのため結
晶の比容積が大きくなり、この結果結晶の分離回
収が困難となる。なお、撹拌周速が極端に遅くな
ると液の混合が均一に行われず、結晶化が不充分
になることは言うまでもない。
以下に本発明の一実施態様を第２図に従つて説
明する。
廃液７を重金属イオン分離処理槽１に受け入れ
たのち、重金属分離薬品として苛性ソーダなどの
アルカリ剤８を注入し空気などによりよく撹拌し
てPH10以上、望ましくはPH12以上にする。次に、
銅イオンを含有している廃液の場合には、硫化ア
ルカリを銅の1.0〜1.1倍当量を加え銅イオンを分
離する。また鉄（）イオン含有の廃液について
は空気などで撹拌、酸化し鉄（）イオンにす
る。ここで分離される重金属イオンは水酸化物あ
るいは硫化物のような不溶性のものとなり沈殿す
るが、この場合、高分子凝集剤等の助剤を添加す
ることは分離効果を助長する。
沈殿分離後、移送ポンプ９で移送管１０を経由
して活性炭ろ過槽２へ、さらに移送管１１を通じ
てEDTA結晶反応槽３へ、移送管１３を経て
EDTA結晶反応槽４へ、移送管１４を経て分離装
置５へ、移送管１５を通じて受け槽６へと連続的
に移送し、分離処理槽１の分離液を処理する。ま
た、分離処理槽１で発生する沈殿物は脱水機等に
より処理し、その脱離液も同じルートで結晶を回
収する。
結晶反応槽３から受け槽６までのフローは高低
差を与えることによる自然流下法で行うことも可
能で、ポンプ等の動力を節約することができる。
結晶反応槽３では撹拌を与えながら酸１２を加
えPH1.3〜1.8の範囲になるようにする。ここに用
いる酸は硫酸、塩酸などの無機酸で、廃液７にカ
ルシウムイオンが1000ppm以上含まれる場合に
は塩酸を用いる。結晶反応槽３，４での反応時間
はそれぞれ15分、合計30分間程度で充分である。
分離装置５でEDTAの結晶を分離し、分離液は
移送管１５を通して受け槽６へ移送するが、分離
装置５で30分以上の滞留を与えることで結晶はさ
らに成長し、溶解しているEDTAの濃度を低下さ
せることができる。
分離装置５で分離されたEDTAの結晶は、水洗
により夾雑水を除くことによつて簡単に純度の高
い結晶として回収することができる。EDTAの回
収率、純度については実施例及び比較例に示す如
く充分再利用可能な良好のものであつた。
以上のように本発明は、EDTAと結合した重金
属イオンを含む廃液からEDTAを効率よく回収し
てその再利用を図ることができ、本発明により化
学洗浄廃液の合理的な処理が可能となつた。
次に、本発明の実施例について記す。
実施例
被処理液の組成は、次表のとおりである。
The present invention relates to a method for treating chemical cleaning waste liquid, and particularly to a method for treating chemical cleaning waste liquid containing heavy metal ions combined with ethylenediaminetetraacetic acid (hereinafter abbreviated as "EDTA"). Conventionally, EDTA has been widely used as a chelate cleaning agent to remove scale from boilers, heat exchangers, piping, etc. This cleaning waste liquid contains multiple heavy metal ions combined with EDTA during the cleaning process and a high concentration of COD, and there has been a long-awaited need to develop an efficient waste liquid treatment method. As a result of intensive research, the present invention has revealed that EDTA is extracted from waste liquid.
This makes it possible to collect and reuse waste. That is, the present invention provides a method for treating chemical cleaning waste liquid containing heavy metal ions combined with EDTA, a first step of adding an alkali to the waste liquid and precipitating and separating the heavy metal ions at a pH of 10 or higher, and a step of separating the separated liquid of the first step. A second step in which fine particles and inhibitors are removed from the separated liquid by passing it through an activated carbon filtration layer, and an acid is added to the filtrate from the second step to adjust the pH to 1.3~
This method of treating chemical cleaning waste liquid containing EDTA is characterized by comprising a third step of generating EDTA crystals in a range of 1.8 and separating and collecting the crystals. The processing method of the present invention will be explained in detail below. In the treatment method of the present invention, first, an alkali is added to the waste liquid to separate heavy metal ions chelating with EDTA from EDTA. In the separation process, an alkaline agent such as caustic soda is injected to separate the liquid.
It is necessary to have a pH of 10 or higher, but if copper ions or nickel ions are contained, the pH should be 12 or higher, preferably 12.5. Furthermore, if it contains iron () ions, it is desirable to oxidize it into iron () ions by aeration with air. This is because if it is an iron () ion, it needs to be PH12.5 or higher, but if it is an iron () ion, a pH of 12 is sufficient, which means that the amount of alkali agent added is small and it is economical. Although any method can be used to oxidize iron () ions (for example, using an oxidizing agent), aeration using air is simple and economical. If the waste liquid contains ammonia, copper ions and nickel ions cannot be dissociated even at pH 12.5. To dissociate this, the pH must be 14 or higher. Therefore, copper ions can be separated as copper sulfide by adding an alkali sulfide such as sodium sulfide or ammonium sulfide in an amount of 1.0 to 1.1 equivalents of copper ions. In this case, the pH of the liquid only needs to be alkaline, so the amount of alkaline agent used can be saved and it is economical. In addition to caustic soda and alkali sulfide, slaked lime and caustic potash can also be used as the alkali. Furthermore, in the separation of heavy metals, the separation is effected by allowing the metal to stand as is, but adding a polymer flocculant is effective in increasing the speed of separation and reducing the volume of the precipitate. Next, fine particles in the separated liquid in which heavy metal ions were precipitated and separated in the first step are removed by passing it through an activated carbon filtration layer. The microparticles in the separation liquid are mainly composed of colloidal iron hydroxide, and cannot be sufficiently separated only by standing still. These microparticles are generated in the following third step.
It adheres to EDTA crystals and causes significant contamination. Further, the precipitate is subjected to dehydration treatment, and EDTA is also separated from this desorbed liquid, but in this case as well, the desorbed liquid contains more microparticles than the separated supernatant liquid. Therefore, it is necessary to remove the microparticles. As a removal treatment method for this purpose, filtration using activated carbon is the most effective method, and microparticles are completely removed. There is also a sand filtration method as a similar filtration method, but it is practically difficult to completely remove these microparticles, and even with a filter method, the sand filtration method
Although it can be completely removed by using a substance of less than m, the captured amount is so small that it is impractical. Therefore, the best method is to filter using activated carbon. Furthermore, activated carbon has a high adsorptive property, and therefore has the effect of removing high molecular weight inhibitors contained in the cleaning liquid, so it has both effects. Next, an acid is added to the filtrate filtered in the second step to generate EDTA crystals, and the crystals are separated and recovered. The pH range of the liquid during crystal formation of EDTA varies depending on the concentration of EDTA, but is PH4.0 to 1.0. Figure 1 shows the results of a detailed investigation of the relationship between EDTA crystallization and pH. This was done by crystallizing a 4% aqueous solution of EDTA at each pH, and examining the amount of EDTA remaining in the filtrate after precipitation and separation over time at each pH. From this figure, it can be seen that when the pH is below 1.3 or above 1.8, the crystallization rate gradually slows down and the solubility of EDTA also increases, and therefore the best condition is a pH range of 1.3 to 1.8. . Furthermore, when separating and recovering EDTA from the filtrate in a continuous manner, a method in which two or more crystal formation reaction tanks are connected in series is more advantageous than a method in which the process is carried out in a single tank with the same residence time. If this is done continuously in a single tank, there is a certain probability that short passes will occur and unreacted
EDTA will flow out, but if this is done with two or more tanks in series, the probability of a short pass will be extremely small, and it will be possible to reach almost the solubility of EDTA, that is, to completely crystallize it, so it will be possible to recover it. This is because it leads to an improvement in the ratio. Furthermore, regarding the stirring of the liquid among the conditions for crystallization, a peripheral stirring speed of about 1.2 m/sec is sufficient, but if this speed is extremely high, the crystals will become fragmented or a large number of crystal nuclei will be generated. Become. Therefore, the specific volume of the crystal becomes large, and as a result, it becomes difficult to separate and recover the crystal. It goes without saying that if the stirring circumferential speed is extremely slow, the liquids will not be mixed uniformly and crystallization will be insufficient. An embodiment of the present invention will be described below with reference to FIG. After the waste liquid 7 is received in the heavy metal ion separation treatment tank 1, an alkaline agent 8 such as caustic soda is injected as a heavy metal separation chemical and stirred well with air to adjust the pH to 10 or higher, preferably 12 or higher. next,
In the case of waste liquid containing copper ions, add alkali sulfide in an amount of 1.0 to 1.1 times the equivalent of copper to separate the copper ions. In addition, waste liquid containing iron () ions is agitated with air, etc., and oxidized to form iron () ions. The heavy metal ions separated here become insoluble substances such as hydroxides or sulfides and precipitate, but in this case, adding an auxiliary agent such as a polymer flocculant will enhance the separation effect. After precipitation and separation, it is transferred to the activated carbon filtration tank 2 via the transfer pipe 10 using the transfer pump 9, and then to the EDTA crystal reaction tank 3 via the transfer pipe 11, and then via the transfer pipe 13.
The separated liquid in the separation treatment tank 1 is continuously transferred to the EDTA crystal reaction tank 4, to the separation device 5 via the transfer pipe 14, and to the receiving tank 6 via the transfer pipe 15, to treat the separated liquid in the separation treatment tank 1. Further, the precipitate generated in the separation treatment tank 1 is treated with a dehydrator or the like, and the crystals of the separated liquid are recovered by the same route. The flow from the crystal reaction tank 3 to the receiving tank 6 can also be carried out by a gravity flow method by providing a difference in height, and the power of a pump etc. can be saved. In crystal reaction tank 3, acid 12 is added while stirring to adjust the pH to a range of 1.3 to 1.8. The acid used here is an inorganic acid such as sulfuric acid or hydrochloric acid, and if the waste liquid 7 contains 1000 ppm or more of calcium ions, hydrochloric acid is used. The reaction time in the crystal reaction tanks 3 and 4 is 15 minutes each, and a total of about 30 minutes is sufficient. The EDTA crystals are separated in the separation device 5, and the separated liquid is transferred to the receiving tank 6 through the transfer pipe 15. However, by allowing the separation device 5 to stay for 30 minutes or more, the crystals grow further, and the dissolved EDTA can reduce the concentration of The EDTA crystals separated by the separator 5 can be easily recovered as highly pure crystals by removing contaminated water by washing with water. As shown in Examples and Comparative Examples, the recovery rate and purity of EDTA were good enough to allow sufficient reuse. As described above, the present invention can efficiently recover and reuse EDTA from waste liquid containing heavy metal ions combined with EDTA, and the present invention has made it possible to rationally treat chemical cleaning waste liquid. . Next, examples of the present invention will be described. Example The composition of the liquid to be treated is shown in the following table.
【表】
上記組成の液を空気で撹拌しながら苛性ソーダ
を2300ｇ投入し充分酸化したところPH12.6となつ
た、これに硫化ナトリウム（Na2S・9H2O）を銅
イオンの1.1当量に相当する2080ｇを投入した。
このときのPHは12.7となつた。
これに高分子凝集剤5ppmを添加し沈殿物を分
離したところ上澄液は無色であつたが、懸濁微小
粒子の存在を認めた。その水質は次のとおりであ
つた。[Table] 2300g of caustic soda was added to the solution with the above composition while stirring with air, and the pH was 12.6 when it was sufficiently oxidized.To this, sodium sulfide (Na 2 S・9H 2 O) was added equivalent to 1.1 equivalents of copper ions. 2080g was added.
The pH at this time was 12.7. When 5 ppm of a polymer flocculant was added to this and the precipitate was separated, the supernatant liquid was colorless, but the presence of suspended microparticles was observed. The water quality was as follows.
【表】
前記第１工程処理液20を用いて、活性炭ろ過
槽を通した後75％の硫酸を比例注入しながら反応
槽３，４で各15分間滞留時間を与え、連続処理し
た。このときの液のPH1.70であり、白色のEDTA
の結晶が生じ、分離装置でこの結晶を分離した。
分離装置内では30分間の滞留時間を与えた。
反応槽３，４の出口の液を5Aのろ紙を用いて
結晶を完全にろ過し、そのろ液のEDTAの濃度を
測定したところ、それぞれ0.14％、0.06％であつ
た。また分離装置５出口の液のEDTAの濃度は
0.05％であつた。ここで回収されたEDTAは白色
の結晶状の粉末でありその量は780ｇであつた。
比較例 １
上記実施例の第１工程処理液について、この実
施例と同様の方法で実験を行なつた。但し硫酸の
比例注入量を増してPH1.1で処理した。そのとき
のEDTAの結晶はやはり白色で結晶状の粉末であ
つた。
反応槽３，４の出口の液を5Aのろ紙を用いて
結晶を完全にろ過し、溶解しているEDTAの濃度
を測定したところ、それぞれ0.36％、0.27％であ
つた。また分離装置５出口の液のEDTAの濃度は
0.25％であつた。ここで回収されたEDTAの量は
740ｇであつた。
比較例 ２
上記実施例の第１工程処理液について、この実
施例と同様の方法で実験を行なつた。但し活性炭
ろ過槽を通さずに実施した。このときのEDTA反
応槽のPHは1.75であつた。反応槽内はSSに由来
する黄土色の濁りが認められ、分離装置５出口の
液は透明であるが、やや黄色を呈していることが
認められた。
また、ここで回収されたEDTAは著しい黄土色
を呈していた。回収されたEDTAは775ｇであつ
た。
前記実施例および比較例で分離回収された
EDTAは、それぞれ３の純水（１μｍ／cm以
下）で水洗した。水洗水の水質は次表に示す値で
あつたので水洗を止め、EDTAを乾燥してその重
量を測[Table] The first step treatment solution 20 was passed through an activated carbon filtration tank, and then 75% sulfuric acid was injected proportionally, and a residence time of 15 minutes was given in each of reaction tanks 3 and 4 for continuous processing. The pH of the liquid at this time is 1.70, and the white EDTA
Crystals were formed and separated using a separator.
A residence time of 30 minutes was allowed in the separator. The crystals were completely filtered from the liquids at the outlets of reaction vessels 3 and 4 using 5A filter paper, and the EDTA concentration of the filtrate was measured and found to be 0.14% and 0.06%, respectively. Also, the concentration of EDTA in the liquid at the outlet of separator 5 is
It was 0.05%. The EDTA recovered here was a white crystalline powder, and the amount was 780 g. Comparative Example 1 An experiment was conducted using the first step treatment liquid of the above example in the same manner as in this example. However, the proportional injection amount of sulfuric acid was increased to maintain pH 1.1. The EDTA crystals at that time were still white and crystalline powder. The liquids at the outlets of reaction vessels 3 and 4 were completely filtered to remove crystals using 5A filter paper, and the concentrations of dissolved EDTA were measured and found to be 0.36% and 0.27%, respectively. Also, the concentration of EDTA in the liquid at the outlet of separator 5 is
It was 0.25%. The amount of EDTA recovered here is
It was 740g. Comparative Example 2 An experiment was conducted using the first step treatment liquid of the above example in the same manner as in this example. However, it was carried out without passing through an activated carbon filtration tank. At this time, the pH of the EDTA reaction tank was 1.75. Ocher-colored turbidity originating from SS was observed inside the reaction tank, and although the liquid at the outlet of separation device 5 was clear, it was observed to have a slightly yellow color. Furthermore, the EDTA recovered here had a remarkable ocher color. The amount of EDTA recovered was 775g. Separated and recovered in the above examples and comparative examples
EDTA was washed with 3 portions of pure water (1 μm/cm or less). The water quality of the washing water was as shown in the table below, so we stopped washing, dried the EDTA, and measured its weight.
【表】
定したが、その値は先に示したとおりである。こ
れらの回収したEDTA中の不純物とEDTAの純度
を測定したところ次表のようであつた。[Table] The values are as shown above. The impurities in these recovered EDTA and the purity of EDTA were measured and the results were as shown in the following table.
【表】
上述の結果より、本発明の実施例においては
EDTA濃度（純度）が優れ、かつEDTAの回収率
も高く、良好な処理結果を示していることがよく
わかる。[Table] From the above results, in the examples of the present invention
It is clearly seen that the EDTA concentration (purity) is excellent and the EDTA recovery rate is also high, indicating good treatment results.
第１図はEDTAの溶解度曲線であり、第２図
は、本発明の一実施態様を示すフローシートであ
る。
１…分離処理槽、２…活性炭ろ過槽、３，４…
結晶反応槽、５…分離装置、６…受け槽、７…廃
液、８…アルカリ剤、９…移送ポンプ、１０，１
１，１３，１４，１５…移送管、１２…酸。
FIG. 1 is a solubility curve of EDTA, and FIG. 2 is a flow sheet showing one embodiment of the present invention. 1... Separation treatment tank, 2... Activated carbon filtration tank, 3, 4...
Crystal reaction tank, 5... Separation device, 6... Receiving tank, 7... Waste liquid, 8... Alkaline agent, 9... Transfer pump, 10, 1
1, 13, 14, 15...transfer pipe, 12...acid.
Claims (1)
オンを含む化学洗浄廃液の処理方法において、 ａ 該廃液にアルカリを添加してPH10以上で重金
属イオンを沈殿分離させる第１工程、 ｂ 前記第１工程の分離液を活性炭ろ過層を通す
ことにより該分離液中の微粒子やインヒビター
を除去する第２工程、 ｃ 前記第２工程のろ過液に酸を添加して、PH
1.3〜1.8の範囲にてエチレンジアミン四酢酸の
結晶を生成させ、該結晶を分離回収する第３工
程、 とからなることを特徴とするエチレンジアミン四
酢酸を含む化学洗浄廃液の処理方法。 ２ 前記廃液が、エチレンジアミン四酢酸と結合
した重金属イオンとして鉄イオン、銅イオンのい
ずれか少なくとも一方を含むものである特許請求
の範囲第１項記載の方法。 ３ 前記鉄イオンが鉄（）イオンである場合に
は、予め酸化して鉄（）イオンとした後、前記
アルカリを添加する特許請求の範囲第２項記載の
方法。 ４ 前記第１工程で添加されるアルカリが、硫化
アルカリである特許請求の範囲第１項記載の方
法。 ５ 前記第２工程のろ過液がカルシウムイオンを
含む場合には、前記酸として塩酸を添加する特許
請求の範囲第１項記載の方法。[Claims] 1. A method for treating chemical cleaning waste liquid containing heavy metal ions combined with ethylenediaminetetraacetic acid, comprising: a. A first step of adding an alkali to the waste liquid to precipitate and separate heavy metal ions at a pH of 10 or higher; b. A second step of removing fine particles and inhibitors in the separated liquid by passing the separated liquid of the first step through an activated carbon filtration layer, c. Adding an acid to the filtrate of the second step to adjust the pH.
1. A method for treating chemical cleaning waste liquid containing ethylenediaminetetraacetic acid, comprising: a third step of generating crystals of ethylenediaminetetraacetic acid in a range of 1.3 to 1.8, and separating and recovering the crystals. 2. The method according to claim 1, wherein the waste liquid contains at least one of iron ions and copper ions as heavy metal ions combined with ethylenediaminetetraacetic acid. 3. The method according to claim 2, wherein when the iron ion is an iron() ion, the alkali is added after oxidizing the iron() ion in advance. 4. The method according to claim 1, wherein the alkali added in the first step is an alkali sulfide. 5. The method according to claim 1, wherein when the filtrate in the second step contains calcium ions, hydrochloric acid is added as the acid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7307583A JPS59222292A (en) | 1983-04-27 | 1983-04-27 | Treatment of waste liquid of chemical cleaning containing ethylenediamine tetraacetate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7307583A JPS59222292A (en) | 1983-04-27 | 1983-04-27 | Treatment of waste liquid of chemical cleaning containing ethylenediamine tetraacetate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59222292A JPS59222292A (en) | 1984-12-13 |
| JPS6235837B2 true JPS6235837B2 (en) | 1987-08-04 |
Family
ID=13507842
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7307583A Granted JPS59222292A (en) | 1983-04-27 | 1983-04-27 | Treatment of waste liquid of chemical cleaning containing ethylenediamine tetraacetate |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59222292A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03124843U (en) * | 1990-03-30 | 1991-12-18 |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5102640A (en) * | 1990-06-29 | 1992-04-07 | Schlapfer Carl W | Process for removing metal ions from solution with a dipicolylamine chemically bound to the surface of a silicate |
| IL109249A0 (en) * | 1994-04-07 | 1994-07-31 | Weizmann Kiryat Membrane Prod | Process and system for purifying a contaminated caustic feed solution |
| DE19619828A1 (en) * | 1996-05-16 | 1997-11-20 | Roger Noero | Process for the preparation of photographic baths from color processes |
| JP4765146B2 (en) * | 2000-07-03 | 2011-09-07 | 三菱瓦斯化学株式会社 | Process for producing polyphenylene ether |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5243453A (en) * | 1975-10-02 | 1977-04-05 | Furuno Electric Co Ltd | Ultrasonic detector |
| JPS57147493A (en) * | 1981-03-09 | 1982-09-11 | Kurita Water Ind Ltd | Treatment of chemical cleaning waste liquid |
| JPS5876177A (en) * | 1981-10-30 | 1983-05-09 | Kurita Water Ind Ltd | Purification of phosphate-contg. water |
-
1983
- 1983-04-27 JP JP7307583A patent/JPS59222292A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5243453A (en) * | 1975-10-02 | 1977-04-05 | Furuno Electric Co Ltd | Ultrasonic detector |
| JPS57147493A (en) * | 1981-03-09 | 1982-09-11 | Kurita Water Ind Ltd | Treatment of chemical cleaning waste liquid |
| JPS5876177A (en) * | 1981-10-30 | 1983-05-09 | Kurita Water Ind Ltd | Purification of phosphate-contg. water |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03124843U (en) * | 1990-03-30 | 1991-12-18 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59222292A (en) | 1984-12-13 |
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