CA1076273A - Oxidation of waste water containing sulphide, sulphite and/or thiosulphate - Google Patents
Oxidation of waste water containing sulphide, sulphite and/or thiosulphateInfo
- Publication number
- CA1076273A CA1076273A CA258,299A CA258299A CA1076273A CA 1076273 A CA1076273 A CA 1076273A CA 258299 A CA258299 A CA 258299A CA 1076273 A CA1076273 A CA 1076273A
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- Prior art keywords
- waste water
- oxidation
- process according
- catalyst
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Classifications
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/725—Treatment of water, waste water, or sewage by oxidation by catalytic oxidation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/06—Treatment of sludge; Devices therefor by oxidation
- C02F11/08—Wet air oxidation
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
Abstract
Bayer 2858 LH/jc OXIDATION OF WASTE WATER CONTAINING SULPHIDE, SULPHITE AND/OR THIOSULPHATE
Abstract of the Disclosure A process for the oxidation of waste water containing one or more of sulphide, sulphite and thiosulphate, with gases containing oxygen, wherein the waste water, if it contains sul-phide, is first brought into contact at a pH > 7 and a tempera-ture of about 20 to 200°C with oxygen-containing gases at from normal pressure up to about 20 bars, until the totality of the sulphide is substantially converted into thiosulphate, then reacted at a pH of approximately 0 to 5, or from 0 to 8 for a waste water containing only sulphite, and at a temperature of about 20 to 200°C with oxygen-containing gases at from normal pressure up to about 20 bars, optionally in the presence of a catalyst, until the practically complete formation of sulphate, with sulphur addition-ally being separated in the ease of waste water containing sul-phide and/or thiosulphate. The catalyst may comprise copper, cobalt and/or iron and be present in about 0.1 to 100 ppm of solution. Advantageously the oxidations are effected in bub-ble columns, each with a packed column downstream thereof.
Le A 16 577
Abstract of the Disclosure A process for the oxidation of waste water containing one or more of sulphide, sulphite and thiosulphate, with gases containing oxygen, wherein the waste water, if it contains sul-phide, is first brought into contact at a pH > 7 and a tempera-ture of about 20 to 200°C with oxygen-containing gases at from normal pressure up to about 20 bars, until the totality of the sulphide is substantially converted into thiosulphate, then reacted at a pH of approximately 0 to 5, or from 0 to 8 for a waste water containing only sulphite, and at a temperature of about 20 to 200°C with oxygen-containing gases at from normal pressure up to about 20 bars, optionally in the presence of a catalyst, until the practically complete formation of sulphate, with sulphur addition-ally being separated in the ease of waste water containing sul-phide and/or thiosulphate. The catalyst may comprise copper, cobalt and/or iron and be present in about 0.1 to 100 ppm of solution. Advantageously the oxidations are effected in bub-ble columns, each with a packed column downstream thereof.
Le A 16 577
Description
~7g;~73 In the chemical industry, for example in paper and pigment production9 large quantities of waste waters occur contuining sulfide, sul~ite and thiosulfate in particular in the form of their sodium salts, It is known to convert sodium sulfide substantially into thiosul~ate by air oxidation ~Air oxidation of sulfides ln process waters and caustic solutions~ Proc. AP I 36 (II) 19569 313~317). It is also known that the oxidation with gases containing oxygen of sodium sul~ide and sodium thiosulfate to form sodium sulfate only happens slowly (Erd~l and Kohle, 14 (1961), 8, 621 - 626).
In order ~o ~ccelerate the reaction, high temperatures o~
approximately 250C , high pressures and long residence times (German O~fenleg~ngsschri~t No. 2,~34,994) are used.
During the oxidation with air of waste wate.r~ containing bisulfite large quantities of S02 are driven of$, so that a waste gas problem arises from the waste water problem.
~ he object of the present invention i~ to develop ~
simple process for the oxidation of waste water~ containing sulf~de 9 ~ul~ite and thiosul~ate, which may contain any proportion of the ~ul~ur -containing compounds, in which sub~tantially a quantitative o~idation i~ e~fected u~ to th~
stage o~ -the sul~ate, and in which proces~ op-tionally sul.fur is formed as a by-product.
This object is realized by the present invention which provides a process ~or the oxidation o~ wa~te waters containing sul~ide, sulfite and thiosul~ate, containing these sulfur-con-taining compounds i~dividually or in any combination, by oxidation with oxygen-containlng ga~ in aqueous solution, characterised in that the waste waters9 in the case where they contain sulfide are first brought i~to contact at p~ values ~ 7 and Le A 16 577 ~lJ76~7~
temperatures of about 20 to 200C with o,Yygen at a pressure from about atmospheric up to 20 bars 9 untll the total sulfide content is substantlally converted into thiosulfate~ a~d then reacted at pH values of from 0 to 5, or from 0 to 8 in the ~ase of a waste water containing only sul~lte, and at temperature~
of about 20 to 200C with oxygen at a pressure from about atmospheric up to 20 bars, optionally in the presence of a catalyst until the substantially complete ~ormation of sulfate 9 with sulfur additionally being separated in the case o.~ waste water containing sulf~de and/or thiosulfate.
The term sul~ide ln the sense o~ the present invention includes hydrogen sulfide or polysulfides, and the term sul~ite lncludes hydrogen sulf~te~. The oxygen employed in the practice of the .present invention i~ pre~erably commerci~lly pure, i. e. it compr~ises at least 90 ~o by volume, preferabl~
99 % by volume 2~ The sulfurous compounds in the waste water are generally present in the ~orm of ~alts, preferably in the form of the alkali metal, alkaline earth metal or ammonium salts;
howe~er the fundamental acid~ and/or acid anhydrides can also be oxidized according to the in~ention.
The oxidation of waste wators containing sul~ide into thio~ulfate is effected pre.~erabl~ at temperature~ o~ about 100 to 140C at pressures of about 1 to 10 bars, and pH values of about 10 to 14, while the ox~dation in the acid pH range iq e~ected preferably at pH value~ o~ about 1 to 3 at temperatures between about 70 and 150C and at pre3sures o~ about 1 to 10 bars.
The oxidation in the acid pH range i3 pre~erably accelerated by the addition of cataly~ts (redox-catalysts), such as copper salt~, e. g. ~US04~ CuC12, cobalt salts, e. g. CoS04, CoC12, iron salt~, 3uch a~ Fe(II) ~nd~or Fe(III) ~alts, S~08 /2 S04 , Le A 16 577 - 2 --, ~'76Z7~
C104/Cl containing salts. Particularly sultable iron salts are FeC12, Fe2(S04)3, FeS04 and FeC13. It is particularly favorable if the ratio o~ Fe(III):Fe(II) ions is adjusted to values between about 1 : 1 and 8 : 19 preferably 2 : 1 and 8 : 1.
The appropriate redox~cataly~t ratio is realized i~ a sample stream of the oxidi~ed waste water, cooled to 20 - 40C, shows at normal pressure and at a pH in between 1 - 3 a redox potential of about 300 to 600 mV, measured with a platinum electrode (Ag/AgCl as reference electrode). The catalysts in this case are used in quantities o~ from approximately 0.01 to 1000 ppm, pre~erably 0,1 to 100 ppm relative to the aqueous solution.
According to the process of the invention, in the event of sulfide being pre~ent in the waste water, this i~ first oxidized to thio~ulfate, and in the sub~equent stage of the process with further oxidation in the acid pH range aul~ate is formed with the simult~neous separation o~ 8ul*ur. In addition thio~ul~ate is ~ormed in the simultaneous presence of~ul~ites and ~ul~de. This proce~s i~ illustrated below for sodium ~ul~ide with reference to a simplified reaction
In order ~o ~ccelerate the reaction, high temperatures o~
approximately 250C , high pressures and long residence times (German O~fenleg~ngsschri~t No. 2,~34,994) are used.
During the oxidation with air of waste wate.r~ containing bisulfite large quantities of S02 are driven of$, so that a waste gas problem arises from the waste water problem.
~ he object of the present invention i~ to develop ~
simple process for the oxidation of waste water~ containing sulf~de 9 ~ul~ite and thiosul~ate, which may contain any proportion of the ~ul~ur -containing compounds, in which sub~tantially a quantitative o~idation i~ e~fected u~ to th~
stage o~ -the sul~ate, and in which proces~ op-tionally sul.fur is formed as a by-product.
This object is realized by the present invention which provides a process ~or the oxidation o~ wa~te waters containing sul~ide, sulfite and thiosul~ate, containing these sulfur-con-taining compounds i~dividually or in any combination, by oxidation with oxygen-containlng ga~ in aqueous solution, characterised in that the waste waters9 in the case where they contain sulfide are first brought i~to contact at p~ values ~ 7 and Le A 16 577 ~lJ76~7~
temperatures of about 20 to 200C with o,Yygen at a pressure from about atmospheric up to 20 bars 9 untll the total sulfide content is substantlally converted into thiosulfate~ a~d then reacted at pH values of from 0 to 5, or from 0 to 8 in the ~ase of a waste water containing only sul~lte, and at temperature~
of about 20 to 200C with oxygen at a pressure from about atmospheric up to 20 bars, optionally in the presence of a catalyst until the substantially complete ~ormation of sulfate 9 with sulfur additionally being separated in the case o.~ waste water containing sulf~de and/or thiosulfate.
The term sul~ide ln the sense o~ the present invention includes hydrogen sulfide or polysulfides, and the term sul~ite lncludes hydrogen sulf~te~. The oxygen employed in the practice of the .present invention i~ pre~erably commerci~lly pure, i. e. it compr~ises at least 90 ~o by volume, preferabl~
99 % by volume 2~ The sulfurous compounds in the waste water are generally present in the ~orm of ~alts, preferably in the form of the alkali metal, alkaline earth metal or ammonium salts;
howe~er the fundamental acid~ and/or acid anhydrides can also be oxidized according to the in~ention.
The oxidation of waste wators containing sul~ide into thio~ulfate is effected pre.~erabl~ at temperature~ o~ about 100 to 140C at pressures of about 1 to 10 bars, and pH values of about 10 to 14, while the ox~dation in the acid pH range iq e~ected preferably at pH value~ o~ about 1 to 3 at temperatures between about 70 and 150C and at pre3sures o~ about 1 to 10 bars.
The oxidation in the acid pH range i3 pre~erably accelerated by the addition of cataly~ts (redox-catalysts), such as copper salt~, e. g. ~US04~ CuC12, cobalt salts, e. g. CoS04, CoC12, iron salt~, 3uch a~ Fe(II) ~nd~or Fe(III) ~alts, S~08 /2 S04 , Le A 16 577 - 2 --, ~'76Z7~
C104/Cl containing salts. Particularly sultable iron salts are FeC12, Fe2(S04)3, FeS04 and FeC13. It is particularly favorable if the ratio o~ Fe(III):Fe(II) ions is adjusted to values between about 1 : 1 and 8 : 19 preferably 2 : 1 and 8 : 1.
The appropriate redox~cataly~t ratio is realized i~ a sample stream of the oxidi~ed waste water, cooled to 20 - 40C, shows at normal pressure and at a pH in between 1 - 3 a redox potential of about 300 to 600 mV, measured with a platinum electrode (Ag/AgCl as reference electrode). The catalysts in this case are used in quantities o~ from approximately 0.01 to 1000 ppm, pre~erably 0,1 to 100 ppm relative to the aqueous solution.
According to the process of the invention, in the event of sulfide being pre~ent in the waste water, this i~ first oxidized to thio~ulfate, and in the sub~equent stage of the process with further oxidation in the acid pH range aul~ate is formed with the simult~neous separation o~ 8ul*ur. In addition thio~ul~ate is ~ormed in the simultaneous presence of~ul~ites and ~ul~de. This proce~s i~ illustrated below for sodium ~ul~ide with reference to a simplified reaction
2~ diagram Ia and Ib in an alkaline medium and II in an acid medium:
In alkaline medium:
I a) 2 Na2S ~ 2 2 ~ H20 ~~~~~~ N~2S23 ~ 2 NaOH
I b) Na2S + S02 ~ 1/2 2 > Na2S~03 In acid medium:
II) Na2S23 ~ S ~ NaES03 + 1/2 ~2 ~ NaES04 If the oxldation is carried out in the acid p~ range at temperature~ aboYe the ~elting poi~t o~ æul~ur the ~ulfur thu~ occurring can be drawn off in llquid form at the botto~ ;
Le A 16 577 - 3 -~7 16~73 of the oxidation containe:r. I~ working below the melting point of sulfur thi~ c~n be ~eparated optionally with the ~ldditional u~e Or flocculation and filtration auxiliary agent~ ~nd al~o on conventional filtration ~pparatus, e.g. filtl~r presses or vacuum ~ilters, The concentration of the sul~urou~ compound~ in the wa~te water can v~ry within relatively wide limits, for example l-ctween about 1 and 200 g/l sulf1de, about l to 150 g/l sulfite, about l to 200 g/l thiosulfate; preferably the figure ~hould be between about 1 to 50 g/l sulfide, about 1 to 100 g/l sulfite, about l to lO0 g/l thiosulfateO In a particularly advantageous embodiment a waste water is treated in which the molar ratio of sulfide/sulfite lies between approximately 1 : 0,6 to 1 : 1,1 or is ad~usted to such a figure~
A continuous process for the oxid~tion of a waste water containing sul~ide, ~ulfite and thio3ulfate i9 de9cribed below with reference to the accompanying drawing schematically ~how~ng a preferred em~odiment of the proces~ according to the invention.
The numbers in the ~igure have the following me~nings:
1, Feed pipe :for waste water containing sulfide.
2. ~ubble column.
In alkaline medium:
I a) 2 Na2S ~ 2 2 ~ H20 ~~~~~~ N~2S23 ~ 2 NaOH
I b) Na2S + S02 ~ 1/2 2 > Na2S~03 In acid medium:
II) Na2S23 ~ S ~ NaES03 + 1/2 ~2 ~ NaES04 If the oxldation is carried out in the acid p~ range at temperature~ aboYe the ~elting poi~t o~ æul~ur the ~ulfur thu~ occurring can be drawn off in llquid form at the botto~ ;
Le A 16 577 - 3 -~7 16~73 of the oxidation containe:r. I~ working below the melting point of sulfur thi~ c~n be ~eparated optionally with the ~ldditional u~e Or flocculation and filtration auxiliary agent~ ~nd al~o on conventional filtration ~pparatus, e.g. filtl~r presses or vacuum ~ilters, The concentration of the sul~urou~ compound~ in the wa~te water can v~ry within relatively wide limits, for example l-ctween about 1 and 200 g/l sulf1de, about l to 150 g/l sulfite, about l to 200 g/l thiosulfate; preferably the figure ~hould be between about 1 to 50 g/l sulfide, about 1 to 100 g/l sulfite, about l to lO0 g/l thiosulfateO In a particularly advantageous embodiment a waste water is treated in which the molar ratio of sulfide/sulfite lies between approximately 1 : 0,6 to 1 : 1,1 or is ad~usted to such a figure~
A continuous process for the oxid~tion of a waste water containing sul~ide, ~ulfite and thio3ulfate i9 de9cribed below with reference to the accompanying drawing schematically ~how~ng a preferred em~odiment of the proces~ according to the invention.
The numbers in the ~igure have the following me~nings:
1, Feed pipe :for waste water containing sulfide.
2. ~ubble column.
3. Discharge pipe for treated wa~ta water in the bubble column.
4' Packed column.
5, Discharge pipe for treated waste water out of the packed column.
6. ~ubble column.
7. Catalyst inlct.
8. Acid inl~t. .-Le A 16 577 _ 4 _ ~L~7~ 3
9. Sul~ur outlet.
10. Oxidizing gas feed pipe for bubble column 2.
11. Oxidizing gas feed pipe for bubble column 6.
12. Branch flow of oxidizing gas for bubble column 6, which is introduced at the base o~ the bubble column 6.
13. Feed pipe ~or waste water containing sulfite or thio-sulfate.
14. Packed column.
15. Sul~ur outlet.
16. Oxidized waste water outlet.
17. Commercially pure oxygen inlet.
18. Gas ~eed pipe.
19. Pump~
20. Ga~ circulati~g pump.
21. Wa~te water overflow.
22. Alkali ~eed.
In detail the treat~ent o~ the wa~$e water containing sulfide 9 sul~ite a~d thiosul~ate i~ e~fected a~ ~ollow~:
Wa~te water containing ~ulfide i3 introduced into the bubble column 2. via feed pipe 1, the pH i~ optionally adjusted by alkali,pre~erably NaOH, introduced via pipe 22, to pH
values greater th~n 7 and treated with o~ygen~ introduced via feed pipe 10~ at average re~idence time~ o~ approximately 5 to 20 minutes. Sub~equently the w~ste water is introduced via the pipe 3 into the packed column 4 ~or ~u~tantially total oxidation intothio~ulfa~e, with oxygen being ~ed via pipe 18.
The wa~te water whoee ~ulfide content ha~ been #ub~tantially converted into thio~ulfate, . leave~ the packed column 4`via the outlet pipe 5 a~d pas~e~ via the pump 19 into the bubble oolumn 6. Acid~ pre~erably ~ulfuric acid, i~ ~ed Le A 16 577 _ 5 _ .. . .
. . . . - : . ~ . ..
3~76~73 via the pipe 8 to adjust the neces~ary acidic p~ range in the bubble column. A catalyst can be supplied to the waste water to be oxidized via 7. Oxygen is fed into the bubble colu~ via the gas circulating pump 20 through pipes 11 and 12.
E~emental sulfur can be removed via the pipe 9. After average residence times o~ from 2 to 20 minutes the waste water issues from the bubble column 6 via the pipe 21 into the packed column 14, where the subst~ltially total oxidation of ~ulfite into sulfate takes place. Both packed column~ 4 and 14 are pre~erably operated in their non-~looded state. Sul~ur in the elemental ~orm can also be removed via the pipe 15.
The commercially pure oxygen iB ~ed in via the pipe 17, and the waste water now containing substantially only sul~ate is discharged via the pipe 16~
In the event of the wa~te water being sul~ide-~ree, the waste water i~ merely ~ed via 13 to the bubble column 6, and the oxidation col~mn~ 2 and 4 are dispen~ed with.
Using the process acoording to the invention it i~
po~eible to carry out the oxidation o~ wa~te waters containing sul~ide, sulfite and thio~ul~ate7 ~orming ~ul~ate ! and sul~ur~ quickly and at relatively low temperatures and pressure~. By separnting the ~ul~ur the quantity o~ oxygen required is reduced compared to known proce~se~, A~ the oxygen ~upplied is substantially qua~titatively used ~or the oxidation, a proced~re is achiaved whieh ts ~ree of waste gase ~, 200 l/hour o~ commercial waete water o~ the composi tion Q~ 34.6 g per 1 ~odium ~ul~ide, 2.5 g par 1 ~odium thiosul~ate and 1.0 g per 1 ~odium ~ulfite were fed continuou~ly in a Le A 16 577 6 -.. . . .
. . . . .
.. . .
. .
~76'~73 semi-technical installation according to Figure 1.
After pa~sing the ~iret ~tage (alkaline oxidation), i.e.
the bubble column 2 and packed column 4 at temperatures of 120C in the bubble column and in the packed column and at pressures of 4.5 bar~ o~ oxygen fed through 17 via 10, the water removed at 5 contained oO6 g per 1 sodium ~ulfide~ 35.4 g sodium thiosul~ate and 1,O g per 1 sodium ~ul~ite. After the subsequent oxidation in the bubble column 6 and in the packed column 14, whioh were operated at temparatures of 130 C, the waste water contain~d only 2.5 g per 1 sodium thio~ulfate and otherwise sodium bi~ulfate or sodiu~ sulfate.
The total residence time o~ the wa~te water ~or column 2 plus packed column 4 wa~ 4 . 5 minute~ or the bubble colu~n 6 t packed oolumn 14, 25 minute~. In the bubble column 2 ~ packed column 4 the pH value was 14, and in the bubble column 6 ~nd packed col~mn 14 the pH value wa~ 0o6 EXAMPLli ~ ~ 6ulIide-fr~ee wa~te water) 200 1 per hour OI a bisulfite wast0 liquor of ~0 g HS03 /liter ~nd having a pH value o~ 5.1 were introduced at 70 C continuously into the bubble column 6. Oxygen at 5 bar~, introduced via 17, e~ectad the practioally quantitative oxidation o~ the hydrogen sul~ite, as on leaving the second stage no HS03 wa~ detected. In this embodiment o~ the procs3~ according to the invention the o~ygen was o~ly i~troduced via the pipes 11 and 12 into the bubble colu~n 6 and recirculated by ma~ls o~ the ga~ ciroulating pump 20 via the pipa ~2.
~ha ga~ discharge pipe 10 ~hown in Figure 1 can be dispen~ed with in this embodiment.
Le A 16 577 7 O
z73 It will be appreciated that the instant specification and examples are set forth by way of illustration and not limitation, and that various modif icat ions and changes may be made without departing 5 from the spirit and scope of the present inventlon.
Le A 16 577 - 8 - :
. . . . .
In detail the treat~ent o~ the wa~$e water containing sulfide 9 sul~ite a~d thiosul~ate i~ e~fected a~ ~ollow~:
Wa~te water containing ~ulfide i3 introduced into the bubble column 2. via feed pipe 1, the pH i~ optionally adjusted by alkali,pre~erably NaOH, introduced via pipe 22, to pH
values greater th~n 7 and treated with o~ygen~ introduced via feed pipe 10~ at average re~idence time~ o~ approximately 5 to 20 minutes. Sub~equently the w~ste water is introduced via the pipe 3 into the packed column 4 ~or ~u~tantially total oxidation intothio~ulfa~e, with oxygen being ~ed via pipe 18.
The wa~te water whoee ~ulfide content ha~ been #ub~tantially converted into thio~ulfate, . leave~ the packed column 4`via the outlet pipe 5 a~d pas~e~ via the pump 19 into the bubble oolumn 6. Acid~ pre~erably ~ulfuric acid, i~ ~ed Le A 16 577 _ 5 _ .. . .
. . . . - : . ~ . ..
3~76~73 via the pipe 8 to adjust the neces~ary acidic p~ range in the bubble column. A catalyst can be supplied to the waste water to be oxidized via 7. Oxygen is fed into the bubble colu~ via the gas circulating pump 20 through pipes 11 and 12.
E~emental sulfur can be removed via the pipe 9. After average residence times o~ from 2 to 20 minutes the waste water issues from the bubble column 6 via the pipe 21 into the packed column 14, where the subst~ltially total oxidation of ~ulfite into sulfate takes place. Both packed column~ 4 and 14 are pre~erably operated in their non-~looded state. Sul~ur in the elemental ~orm can also be removed via the pipe 15.
The commercially pure oxygen iB ~ed in via the pipe 17, and the waste water now containing substantially only sul~ate is discharged via the pipe 16~
In the event of the wa~te water being sul~ide-~ree, the waste water i~ merely ~ed via 13 to the bubble column 6, and the oxidation col~mn~ 2 and 4 are dispen~ed with.
Using the process acoording to the invention it i~
po~eible to carry out the oxidation o~ wa~te waters containing sul~ide, sulfite and thio~ul~ate7 ~orming ~ul~ate ! and sul~ur~ quickly and at relatively low temperatures and pressure~. By separnting the ~ul~ur the quantity o~ oxygen required is reduced compared to known proce~se~, A~ the oxygen ~upplied is substantially qua~titatively used ~or the oxidation, a proced~re is achiaved whieh ts ~ree of waste gase ~, 200 l/hour o~ commercial waete water o~ the composi tion Q~ 34.6 g per 1 ~odium ~ul~ide, 2.5 g par 1 ~odium thiosul~ate and 1.0 g per 1 ~odium ~ulfite were fed continuou~ly in a Le A 16 577 6 -.. . . .
. . . . .
.. . .
. .
~76'~73 semi-technical installation according to Figure 1.
After pa~sing the ~iret ~tage (alkaline oxidation), i.e.
the bubble column 2 and packed column 4 at temperatures of 120C in the bubble column and in the packed column and at pressures of 4.5 bar~ o~ oxygen fed through 17 via 10, the water removed at 5 contained oO6 g per 1 sodium ~ulfide~ 35.4 g sodium thiosul~ate and 1,O g per 1 sodium ~ul~ite. After the subsequent oxidation in the bubble column 6 and in the packed column 14, whioh were operated at temparatures of 130 C, the waste water contain~d only 2.5 g per 1 sodium thio~ulfate and otherwise sodium bi~ulfate or sodiu~ sulfate.
The total residence time o~ the wa~te water ~or column 2 plus packed column 4 wa~ 4 . 5 minute~ or the bubble colu~n 6 t packed oolumn 14, 25 minute~. In the bubble column 2 ~ packed column 4 the pH value was 14, and in the bubble column 6 ~nd packed col~mn 14 the pH value wa~ 0o6 EXAMPLli ~ ~ 6ulIide-fr~ee wa~te water) 200 1 per hour OI a bisulfite wast0 liquor of ~0 g HS03 /liter ~nd having a pH value o~ 5.1 were introduced at 70 C continuously into the bubble column 6. Oxygen at 5 bar~, introduced via 17, e~ectad the practioally quantitative oxidation o~ the hydrogen sul~ite, as on leaving the second stage no HS03 wa~ detected. In this embodiment o~ the procs3~ according to the invention the o~ygen was o~ly i~troduced via the pipes 11 and 12 into the bubble colu~n 6 and recirculated by ma~ls o~ the ga~ ciroulating pump 20 via the pipa ~2.
~ha ga~ discharge pipe 10 ~hown in Figure 1 can be dispen~ed with in this embodiment.
Le A 16 577 7 O
z73 It will be appreciated that the instant specification and examples are set forth by way of illustration and not limitation, and that various modif icat ions and changes may be made without departing 5 from the spirit and scope of the present inventlon.
Le A 16 577 - 8 - :
. . . . .
Claims (13)
- THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
l. A process for the oxidation of a waste water containing one or more of sulphides, sulphites and thiosulphates, wherein (i) in the presence of a waste water containing a sulphide, the waste water is con-tacted at a pH value greater than 7 and at a temperature of from 20 to 200°C
with commercially pure oxygen at from normal pressure up to a pressure of 20 bars, until substantially all the sulphide is converted into thiosulphate;
(ii) the waste water is reacted at a pH value of from 0 to 5? or from 0 to 8 for a waste water containing only sulphite, and at a temperature of from 20 to 200°C with commercially pure oxygen at from normal pressure up to a pressure of 20 bars, until substantially the complete formation of sulphate;
and (iii) sulphur is additionally separated in the case of a waste water containing a sulphide and/or a thiosulphate. - 2. A process according to claim 1, wherein the oxidation in step (i) of a waste water containing sulphide to form thiosulphate is carried out in an alkaline medium at a temperature of from 100 to 140°C and at pressures of from 1 to 10 bars.
- 3. A process according to claim 1 wherein the oxidation in step (ii) is carried out in an acid medium at a pH value of from 1 to 3 and at a tem-perature between 70 and 150°C and at pressures of from 1 to 10 bars.
- 4. A process according to any of claims 1 to 3, wherein the oxida-tion of step (ii) is carried out in the presence of a catalyst.
- 5. A process according to any of claims 1 to 3 wherein the oxidation of step (ii) is carried out in the presence of a catalyst which is a com-pound containing copper, cobalt and/or iron.
- 6. A process according to any of claims 1 to 3, wherein the oxida-tion of step (ii) is carried out in the presence of a catalyst which contains iron having an iron (III):Fe(II) ion ratio of from 2:1 to 8:1.
\ - 7. A process according to any of claims 1 to 3, wherein the oxidation of step (ii) is carried out in the presence of a catalyst which is a compound of copper, cobalt and/or iron, which catalyst is used in a quantity of from 0.1 to 100 ppm, relative to the aqueous solution.
- 8. A process according to any of claims 1 to 3 wherein the oxidation of step (ii) is carried out in the presence of a catalyst which contains iron having an iron (III):Fe(II)ion ratio of from 2:1 to 8:1, which catalyst is used in a quantity of from 0.1 to 100 ppm, relative to the aqueous solution.
- 9. A process according to any of claims 1 to 3, wherein the waste water contains from 1 to 200 g/l sulphide; 1 to 150 g/l sulphite; 1 to 200 g/l thiosulphate.
- 10. A process according to any of claims 1 to 3, wherein the waste water has a molar ratio of sulphide to sulphite of between 1:0.6 and 1:1.1.
- 11. A process according to any of claims 1 to 3, wherein the oxida-tion is carried out in an alkaline and also in an acid medium in two stages in each case in a bubble column with a packed column arranged downstream.
- 12. A process according to claim 1 wherein the oxidation in step (i) of a waste water containing sulphide to form thiosulphate is carried out in an alkaline medium at a temperature of from 100 to 140°C and at a pressure of from 1 to 10 bars and the oxidation in step (ii) is carried out in an acid medium at a pH of from 1 to 3 and at a temperature between 70 and 150°C
and at a pressure of from 1 to 10 bars. - 13. A process according to claim 12 wherein the oxidation of step (ii) is carried out in the presence of a catalyst which is a compound containing copper, cobalt and/or iron, which catalyst is used in a quantity of from 0.1 to 100 ppm, relative to the aqueous solution.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2534892A DE2534892B2 (en) | 1975-08-05 | 1975-08-05 | Process for the oxidative treatment of wastewater containing sulphides, sulphites and thiosulphates |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1076273A true CA1076273A (en) | 1980-04-22 |
Family
ID=5953254
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA258,299A Expired CA1076273A (en) | 1975-08-05 | 1976-08-03 | Oxidation of waste water containing sulphide, sulphite and/or thiosulphate |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5219469A (en) |
| BE (1) | BE844891A (en) |
| CA (1) | CA1076273A (en) |
| CH (1) | CH623016A5 (en) |
| DE (1) | DE2534892B2 (en) |
| FR (1) | FR2320268A1 (en) |
| GB (1) | GB1534085A (en) |
| NL (1) | NL7608678A (en) |
| SE (1) | SE7608759L (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2615037A1 (en) * | 1976-04-07 | 1977-10-20 | Bayer Ag | REMOVAL OF SULFUR DIOXIDE FROM SULPHITE-CONTAINING WASTE |
| FR2427307A1 (en) * | 1978-05-31 | 1979-12-28 | Air Liquide | Treating aq. effluent contg. sulphide using pressurised oxygen - in a column under specified conditions |
| DE3109064C2 (en) * | 1981-03-10 | 1983-02-24 | Klaus Dr. 8029 Sauerlach Söchting | Dosing method and device for the controllable delivery of oxygen and liquids in biologically used systems |
| IT1136587B (en) * | 1981-04-29 | 1986-09-03 | Prodeco Spa | PROCEDURE FOR THE TREATMENT OF WATERS CONTAINING SULFURS |
| US4699720A (en) * | 1985-03-12 | 1987-10-13 | Osaka Gas Company Limited | Process for treating waste water by wet oxidations |
| EP0634365B1 (en) | 1993-07-16 | 1998-04-15 | BASF Aktiengesellschaft | Breaking down aromatic compounds in industrial wastewaters |
| DE102010049445A1 (en) * | 2010-10-07 | 2012-04-12 | Linde Aktiengesellschaft | Process for waste liquor oxidation under elevated pressure |
| DE102013010217A1 (en) | 2013-06-20 | 2014-12-24 | Eilenburger Elektrolyse- Und Umwelttechnik Gmbh | Process and device for the electrochemical oxidation of sulfide-containing wastewaters |
| RU2626367C2 (en) * | 2015-12-23 | 2017-07-26 | Публичное акционерное общество "Татнефть" имени В.Д. Шашина | Method for purifying water from sulfur compounds |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR808658A (en) * | 1936-07-24 | 1937-02-12 | Water purification process by the catalytic oxidation of materials contained in wastewater, consuming oxygen | |
| GB962237A (en) * | 1961-04-19 | 1964-07-01 | British Petroleum Co | Improvements relating to the oxidation of sulphides in aqueous solutions |
| DE1517659A1 (en) * | 1963-04-06 | 1969-06-19 | Hunold Fuerst | Process for cleaning liquid, dissolved, emulsified or suspended or gaseous media, such as waste water, exhaust gases and the like. |
-
1975
- 1975-08-05 DE DE2534892A patent/DE2534892B2/en not_active Withdrawn
-
1976
- 1976-08-02 CH CH984876A patent/CH623016A5/en not_active IP Right Cessation
- 1976-08-03 JP JP51092099A patent/JPS5219469A/en active Pending
- 1976-08-03 CA CA258,299A patent/CA1076273A/en not_active Expired
- 1976-08-04 GB GB32466/76A patent/GB1534085A/en not_active Expired
- 1976-08-04 SE SE7608759A patent/SE7608759L/en unknown
- 1976-08-04 NL NL7608678A patent/NL7608678A/en not_active Application Discontinuation
- 1976-08-05 FR FR7623995A patent/FR2320268A1/en active Granted
- 1976-08-05 BE BE2055218A patent/BE844891A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| GB1534085A (en) | 1978-11-29 |
| NL7608678A (en) | 1977-02-08 |
| BE844891A (en) | 1977-02-07 |
| DE2534892A1 (en) | 1977-02-17 |
| CH623016A5 (en) | 1981-05-15 |
| DE2534892B2 (en) | 1979-07-05 |
| FR2320268A1 (en) | 1977-03-04 |
| JPS5219469A (en) | 1977-02-14 |
| FR2320268B1 (en) | 1980-11-21 |
| SE7608759L (en) | 1977-02-06 |
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