JPS6158235B2 - - Google Patents
Info
- Publication number
- JPS6158235B2 JPS6158235B2 JP51141419A JP14141976A JPS6158235B2 JP S6158235 B2 JPS6158235 B2 JP S6158235B2 JP 51141419 A JP51141419 A JP 51141419A JP 14141976 A JP14141976 A JP 14141976A JP S6158235 B2 JPS6158235 B2 JP S6158235B2
- Authority
- JP
- Japan
- Prior art keywords
- electrolytic
- hexavalent chromium
- sludge
- anode
- chromium
- 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
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 claims description 22
- 239000010802 sludge Substances 0.000 claims description 19
- 239000002699 waste material Substances 0.000 claims description 11
- 230000001603 reducing effect Effects 0.000 claims description 8
- 239000007788 liquid Substances 0.000 claims description 7
- 239000008151 electrolyte solution Substances 0.000 claims description 6
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- 229910021645 metal ion Inorganic materials 0.000 claims description 4
- 239000007769 metal material Substances 0.000 claims description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 13
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 9
- 229910052804 chromium Inorganic materials 0.000 description 9
- 239000011651 chromium Substances 0.000 description 9
- 229910052742 iron Inorganic materials 0.000 description 9
- 239000003792 electrolyte Substances 0.000 description 8
- -1 iron ions Chemical class 0.000 description 6
- 238000005868 electrolysis reaction Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000006722 reduction reaction Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- XTEGARKTQYYJKE-UHFFFAOYSA-M Chlorate Chemical compound [O-]Cl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-M 0.000 description 3
- 229910001430 chromium ion Inorganic materials 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000001784 detoxification Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 150000002826 nitrites Chemical class 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
- 239000004317 sodium nitrate Substances 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical class [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Removal Of Specific Substances (AREA)
- Treatment Of Sludge (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
Description
【発明の詳細な説明】
本発明は、クロムを含有する鋼合金のような材
料を電気化学的に加工または溶解させた電解廃液
中の電解スラツジについて、そのスラツジ中に生
成含有する六価クロムを除去または減少させるた
めの無害化処理方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electrolytic sludge in an electrolytic waste liquid produced by electrochemically processing or dissolving a material such as a steel alloy containing chromium, and to detect hexavalent chromium generated and contained in the sludge. The present invention relates to a detoxification treatment method for removing or reducing.
例えば、電解加工では形状精度の良好な硝酸塩
または塩素酸塩系の電解液が用いられるため、被
加工物に含まれるクロムは有害な六価クロムイオ
ンとなつて電解液中に溶出し、被加工物の加工量
の増加に伴い液中で濃度を増加していく。このた
め、電解液から鉄の電解スラツジを分離しても、
高濃度の六価クロムを含有するスラツジが得られ
るようになる。 For example, in electrolytic machining, a nitrate or chlorate electrolyte with good shape accuracy is used, so chromium contained in the workpiece becomes harmful hexavalent chromium ions and is eluted into the electrolyte. As the amount of material processed increases, the concentration in the liquid increases. For this reason, even if the iron electrolytic sludge is separated from the electrolyte,
A sludge containing a high concentration of hexavalent chromium is obtained.
このような六価クロム含有電解スラツジを含む
電解廃液は、一般に還元処理法によつて六価クロ
ムを三価クロムにした後アルカリ性にして沈澱処
理されるが、多くの処理工程を必要とし、またス
ラツジの溶解による鉄及びクロムの同時還元もあ
るので問題が多く、この電解廃液に対する公害防
止対策が強く望まれる。 Electrolytic waste containing such hexavalent chromium-containing electrolytic sludge is generally treated by reducing hexavalent chromium to trivalent chromium and then making it alkaline and precipitating it, but it requires many treatment steps and is Simultaneous reduction of iron and chromium due to dissolution of sludge poses many problems, and measures to prevent pollution of this electrolytic waste solution are strongly desired.
上記に鑑み、本発明は電気化学的に加工または
溶解させた電解廃液中の電解スラツジの廃棄処理
を容易にすることを目的として、その電解スラツ
ジ中の六価クロムを除去または減少させようとす
るものである。 In view of the above, the present invention attempts to remove or reduce hexavalent chromium in electrolytic sludge, with the aim of facilitating the disposal of electrolytic sludge in electrolytic waste liquid that has been electrochemically processed or dissolved. It is something.
すなわち、本発明の方法は、六価クロム含有の
電解液と電解スラツジからなる電解廃液、あるい
はそれらを分離してスラツジを水溶液（工業用
水）または電解質を含む水溶液で希釈混合したも
のを電解液として用い、還元作用のある金属イオ
ンを溶出する金属材料を陽極として、陽極近傍に
おける水素イオン指数を低下させる程度に高い電
流効率が得られる15〜45A／cm2程度の電流密度
で、電解液に高流速を与えた電解条件において、
陰極との間に電解電流を流し、電解溶出する金属
イオンの還元作用によつて上記六価クロムを三価
クロムに還元し、水酸化物として処理するもので
ある。 That is, the method of the present invention uses an electrolytic waste solution consisting of an electrolytic solution containing hexavalent chromium and electrolytic sludge, or a mixture obtained by separating them and diluting the sludge with an aqueous solution (industrial water) or an aqueous solution containing an electrolyte, as an electrolytic solution. Using a metal material that elutes reducing metal ions as an anode, a high current density of about 15 to 45 A/cm 2 is obtained, which is enough to reduce the hydrogen ion index near the anode. Under the electrolytic conditions given the flow rate,
An electrolytic current is passed between the cathode and the electrolytically eluted metal ions to reduce the hexavalent chromium to trivalent chromium and treat it as a hydroxide.
本発明によつて処理すべき電解スラツジ含有の
電解質液としては、例えば硝酸塩、塩素酸塩など
をそれぞれ主体とし、それに若干の亜硝酸塩、亜
硫酸塩または他の必要な添加剤を加えて電解加工
に用いたものなどであつて、電気化学的な溶解に
より生ずる六価クロムを含んだものが対象とな
る。 The electrolyte solution containing the electrolytic sludge to be treated according to the present invention is, for example, mainly composed of nitrates, chlorates, etc., with some nitrites, sulfites, or other necessary additives added thereto for electrolytic processing. This applies to materials that contain hexavalent chromium, which is produced through electrochemical dissolution.
而して、本発明においては、陽極（被加工物）
として、例えばクロムを含有しない鉄素地材料を
用いるのが適し、また必要電流効率を得るために
は、六価クロムを含有する電解廃液（スラツジ含
有）に高流速を与えて電解加工の場合と同様な電
流を流すのが通例で、これによつて陽極、陰極で
はスケールの付着防止が可能となる。 Therefore, in the present invention, the anode (workpiece)
For example, it is suitable to use a ferrous base material that does not contain chromium, and in order to obtain the necessary current efficiency, a high flow rate is applied to the electrolytic waste solution (including sludge) containing hexavalent chromium, as in the case of electrolytic processing. Usually, a current is passed through the electrode, and this makes it possible to prevent scale from forming on the anode and cathode.
上記方法によつて六価クロムイオンを三価クロ
ムに還元できるのは、次のような理由によるもの
と考えられる。すなわち、鉄または鉄素地材料を
陽極及び陰極として電解廃液中で電解すると、二
価の鉄イオンが溶出することになるが、この二価
の鉄イオンは一般に強い還元作用があり、その還
元反応は酸性域において行われる。従つて、電解
が行われる陽極近傍においては、多量の電解溶出
鉄イオンの加水分解反応による酸性化の水の分解
等による多量の水素イオンの生成により水素イオ
ン指数が下がり、その結果、上記二価の鉄イオン
の還元作用により電解スラツジを含む廃液中の六
価クロムが直ちに三価クロムに還元され、電極沖
合では水素イオン指数が高いため、それが水酸化
物となつて他の金属と共に電解スラツジを形成す
るものと考えられる。 The reason why hexavalent chromium ions can be reduced to trivalent chromium by the above method is considered to be as follows. In other words, when iron or iron base material is used as an anode and a cathode for electrolysis in an electrolytic waste solution, divalent iron ions are eluted, but these divalent iron ions generally have a strong reducing effect, and the reduction reaction is It is carried out in an acidic region. Therefore, in the vicinity of the anode where electrolysis is performed, the hydrogen ion index decreases due to the generation of a large amount of hydrogen ions due to the decomposition of acidified water due to the hydrolysis reaction of a large amount of electrolytically eluted iron ions, and as a result, the hydrogen ion index decreases. Due to the reducing action of iron ions, hexavalent chromium in the waste liquid containing electrolytic sludge is immediately reduced to trivalent chromium, and since the hydrogen ion index is high offshore of the electrode, it becomes hydroxide and is absorbed into the electrolytic sludge along with other metals. It is thought to form a
また、本発明においては、強いアルカリ性溶液
として得られる電解廃液を直接的に処理するよう
にしているが、この廃液のPH調整を行つて酸性ま
たは中性にした後に電解還元を行うことは、多量
の電解スラツジから三価鉄イオンが再溶解するた
めに、それが六価クロムの還元の障害になるなど
の問題があり、この点を考慮して、本発明の如く
アルカリ性電解を行うことは、六価クロムの還元
処理のために極めて有効である。 In addition, in the present invention, the electrolytic waste liquid obtained as a strong alkaline solution is directly treated, but it is not possible to perform electrolytic reduction after adjusting the pH of this waste liquid to make it acidic or neutral. Since trivalent iron ions are redissolved from the electrolytic sludge, there is a problem that it becomes an obstacle to the reduction of hexavalent chromium. Taking this into consideration, performing alkaline electrolysis as in the present invention is It is extremely effective for reducing hexavalent chromium.
このような本発明方法によれば、電解溶出する
金属イオンの還元作用によつて電解スラツジ中の
六価クロムを短時間で効率的に三価クロムに還元
処理して他の電解スラツジと同様に沈澱させるこ
とができ、しかもその処理装置として一般に電解
加工に用いられている装置及び電源等をそのまま
使用することができ、特別の六価クロムイオンの
還元処理施設が不要となり、無害化された電解ス
ラツジの処理対策のみを考慮すればよく、その取
扱いが非常に容易であるなどの極めてすぐれた特
徴がある。 According to the method of the present invention, the hexavalent chromium in the electrolytic sludge is efficiently reduced to trivalent chromium in a short time by the reducing action of the electrolytically eluted metal ions, and it can be treated similarly to other electrolytic sludges. It can be precipitated, and the equipment and power supply generally used for electrolytic processing can be used as the processing equipment, eliminating the need for special reduction processing facilities for hexavalent chromium ions, making it a harmless electrolytic process. It has extremely excellent features such as being extremely easy to handle and only having to consider measures to dispose of the sludge.
本発明についての実験により得られた結果を第
１図及び第２図に示す。 The results obtained by experiments regarding the present invention are shown in FIGS. 1 and 2.
第１図は、電解によつて２mg／ｌの六価クロム
と電解スラツジを含有する硝酸ナトリウム電解液
を用いて、電解液に流速（10.4m／ｓ）を与えな
がら、定電流電解条件下で、電流密度を5A／
cm2、15A／cm2及び45A／cm2として、その通過電気
量が1000クーロン／cm2になるまで炭素鋼を電解し
た場合の六価クロムの残留濃度を示すもので、
5A／cm2の場合には必要な電流効率が得られない
ため六価クロムの残留濃度はあまり減少しない
が、15A／cm2及び45A／cm2ではその残留濃度が著
しく減少し、電解液中には六価クロムがほとんど
存在しなかつた。 Figure 1 shows the results of electrolysis using a sodium nitrate electrolyte containing 2 mg/l of hexavalent chromium and electrolytic sludge under constant current electrolysis conditions while giving the electrolyte a flow rate (10.4 m/s). , current density 5A/
cm 2 , 15A/cm 2 and 45A/cm 2 , it indicates the residual concentration of hexavalent chromium when carbon steel is electrolyzed until the amount of electricity passing through it reaches 1000 coulombs/cm 2 .
In the case of 5A/ cm2 , the necessary current efficiency cannot be obtained, so the residual concentration of hexavalent chromium does not decrease much, but at 15A/ cm2 and 45A/ cm2 , the residual concentration decreases significantly, and the residual concentration in the electrolyte increases. Almost no hexavalent chromium was present.
また、第２図は上記電解液の流速を変化させた
場合についての実験結果を示すもので、図中の高
流速は10.4m／ｓの場合を、低流速は2.2m／ｓの
場合を表わし、同一電流密度でも電解液を高流速
で電解した場合の方がより効果的に六価クロムの
残留濃度を減少させ得ることを示している。従つ
て上記実験結果から、金属溶解の電流効率が高く
なる条件により本発明の無害化処理は短時間で完
了できることがわかる。 In addition, Figure 2 shows the experimental results when the flow velocity of the electrolyte solution was varied; the high flow velocity in the figure represents the case of 10.4 m/s, and the low flow velocity represents the case of 2.2 m/s. , it has been shown that even at the same current density, the residual concentration of hexavalent chromium can be reduced more effectively when the electrolyte is electrolyzed at a higher flow rate. Therefore, the above experimental results show that the detoxification treatment of the present invention can be completed in a short time under conditions that increase the current efficiency of metal melting.
第１図及び第２図は本発明についての実験結果
を示す線図である。
FIGS. 1 and 2 are diagrams showing experimental results regarding the present invention.
Claims (1)
ムと電解スラツジを含む電解質液を用い、還元作
用のある金属イオンを溶出する金属材料を陽極と
して、陽極近傍における水素イオン指数を低下さ
せる程度に高い電流効率が得られる15〜45A／cm2
程度の電流密度で、電解液に高流速を与えた電解
条件において、陰極との間に電流を流し、電解溶
出する金属イオンの還元作用によつて上記六価ク
ロムを三価クロムに還元することを特徴とする電
解廃液の無害化処理方法。1 Using an electrolyte solution containing hexavalent chromium and electrolytic sludge eluted by electrochemical processing, etc., a metal material that elutes metal ions with a reducing action is used as an anode, and the hydrogen ion index is high enough to reduce the hydrogen ion index near the anode. Current efficiency of 15 to 45 A/cm 2
Under electrolytic conditions in which a high flow rate is applied to the electrolytic solution at a current density of about A method for detoxifying electrolytic waste liquid, characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14141976A JPS5365264A (en) | 1976-11-25 | 1976-11-25 | Treating method for making waste fluid of electrolysis harmless |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14141976A JPS5365264A (en) | 1976-11-25 | 1976-11-25 | Treating method for making waste fluid of electrolysis harmless |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5365264A JPS5365264A (en) | 1978-06-10 |
| JPS6158235B2 true JPS6158235B2 (en) | 1986-12-10 |
Family
ID=15291558
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14141976A Granted JPS5365264A (en) | 1976-11-25 | 1976-11-25 | Treating method for making waste fluid of electrolysis harmless |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5365264A (en) |
-
1976
- 1976-11-25 JP JP14141976A patent/JPS5365264A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5365264A (en) | 1978-06-10 |
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