NO149163B - PROCEDURE FOR WASHING CYANIDE-CONTAINING OBAS GASES FROM THE METALLURGICAL INDUSTRY - Google Patents
PROCEDURE FOR WASHING CYANIDE-CONTAINING OBAS GASES FROM THE METALLURGICAL INDUSTRY Download PDFInfo
- Publication number
- NO149163B NO149163B NO900304A NO800304A NO149163B NO 149163 B NO149163 B NO 149163B NO 900304 A NO900304 A NO 900304A NO 800304 A NO800304 A NO 800304A NO 149163 B NO149163 B NO 149163B
- Authority
- NO
- Norway
- Prior art keywords
- cyanide
- washing
- gases
- gas
- content
- Prior art date
Links
- 239000007789 gas Substances 0.000 title claims description 52
- 238000000034 method Methods 0.000 title claims description 16
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 claims description 51
- 238000005406 washing Methods 0.000 claims description 40
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 9
- 239000001301 oxygen Substances 0.000 claims description 9
- 229910052760 oxygen Inorganic materials 0.000 claims description 9
- 239000007787 solid Substances 0.000 claims description 8
- 238000002485 combustion reaction Methods 0.000 claims description 3
- 238000000926 separation method Methods 0.000 claims description 3
- 239000003344 environmental pollutant Substances 0.000 claims description 2
- 231100000719 pollutant Toxicity 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 43
- LELOWRISYMNNSU-UHFFFAOYSA-N hydrogen cyanide Chemical compound N#C LELOWRISYMNNSU-UHFFFAOYSA-N 0.000 description 14
- 230000001105 regulatory effect Effects 0.000 description 10
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 8
- 150000002825 nitriles Chemical class 0.000 description 7
- 239000001569 carbon dioxide Substances 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 239000000356 contaminant Substances 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 3
- 230000033228 biological regulation Effects 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 238000004062 sedimentation Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 description 2
- RYZCLUQMCYZBJQ-UHFFFAOYSA-H lead(2+);dicarbonate;dihydroxide Chemical compound [OH-].[OH-].[Pb+2].[Pb+2].[Pb+2].[O-]C([O-])=O.[O-]C([O-])=O RYZCLUQMCYZBJQ-UHFFFAOYSA-H 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- XLJMAIOERFSOGZ-UHFFFAOYSA-M cyanate Chemical compound [O-]C#N XLJMAIOERFSOGZ-UHFFFAOYSA-M 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000001784 detoxification Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000008394 flocculating agent Substances 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 231100000206 health hazard Toxicity 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical class [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- DCYOBGZUOMKFPA-UHFFFAOYSA-N iron(2+);iron(3+);octadecacyanide Chemical compound [Fe+2].[Fe+2].[Fe+2].[Fe+3].[Fe+3].[Fe+3].[Fe+3].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] DCYOBGZUOMKFPA-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- NNFCIKHAZHQZJG-UHFFFAOYSA-N potassium cyanide Chemical group [K+].N#[C-] NNFCIKHAZHQZJG-UHFFFAOYSA-N 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 230000029219 regulation of pH Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000005201 scrubbing Methods 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D47/00—Separating dispersed particles from gases, air or vapours by liquid as separating agent
- B01D47/06—Spray cleaning
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D47/00—Separating dispersed particles from gases, air or vapours by liquid as separating agent
- B01D47/10—Venturi scrubbers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2247/00—Details relating to the separation of dispersed particles from gases, air or vapours by liquid as separating agent
- B01D2247/04—Regenerating the washing fluid
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
- Incineration Of Waste (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
- Removal Of Specific Substances (AREA)
- Industrial Gases (AREA)
- Gas Separation By Absorption (AREA)
Description
Foreliggende oppfinnelse vedrører en fremgangsmåte ved vasking av cyanidholdige ovnsgasser som dannes i metallurgisk industri ved behandling med sirkulerende vandig vaskeløsning og separasjon av faste og oppløste forurensninger fra va^feke-løsningen før den tilbakeføres til vasketrinnet, hvorunder den sirkulerende vandige vaskeløsning har en pH verdi på maksimalt 9,5 og de brennbare bestanddeler i de vaskede ovnsgasser fjernes ved forbrenning. The present invention relates to a method for washing cyanide-containing furnace gases which are formed in the metallurgical industry by treatment with circulating aqueous washing solution and separation of solid and dissolved contaminants from the washing solution before it is returned to the washing step, during which the circulating aqueous washing solution has a pH value of maximum 9.5 and the combustible components in the washed furnace gases are removed by combustion.
Spesielt for både høye ovner for stålfremstilling og lukked ferro-krcmovner san anvendes ved fremstilling av stål, er at det dannes gasser under de forhold som råder ved disse prosesser, hvilke gasser i tillegg til karbonmonoksyd, karbondioksyd og hydrogen inneholder cyanider, hovedsaklig alkalicyanider. Da ovnsgassen også inneholder en betydelig mengde fast stoff, må gassen renses før den utnyttes-eller viderebehandles. Ved vasking av gasser anvendes i almin-nelighet våtrensere slik som venturiskrubbere hvor gassens faste stoff samt vannløslige gasser vaskes i vann. På grunn av dette inneholder skrubbervæsken i tillegg til fast stoff også miljøskadelig cyanid. Man har tilstrebet å redusere vaskevannsløsningens cyanidinnhold på forskjellige måter. Especially for both blast furnaces for steel production and closed ferro-crcm furnaces used in the production of steel, gases are formed under the conditions that prevail in these processes, which gases, in addition to carbon monoxide, carbon dioxide and hydrogen, contain cyanides, mainly alkali cyanides. As the furnace gas also contains a significant amount of solids, the gas must be cleaned before it is used - or further processed. When washing gases, wet cleaners such as venturi scrubbers are generally used, where the gas's solids and water-soluble gases are washed in water. Because of this, in addition to solids, the scrubbing liquid also contains environmentally harmful cyanide. Efforts have been made to reduce the wash water solution's cyanide content in various ways.
Ifølge en kjent metode økes cyanidløsningens surhet til pH-verdi ca. 10-11, hvoretter cyanidet oksyderes med et passende oksydasjonsmiddel så som f.eks. klor, hyppklorit, hydrogen-peroksyd, persvovelsyre eller ozon. Som et resultat.av oksy-das jonen blir cyanidet enten cyanat eller, hvis oksydasjonen fullstendiggjøres, nitrogen og hydrogen. According to a known method, the acidity of the cyanide solution is increased to a pH value of approx. 10-11, after which the cyanide is oxidized with a suitable oxidizing agent such as e.g. chlorine, hypochlorite, hydrogen peroxide, persulphuric acid or ozone. As a result of the oxidation ion, the cyanide becomes either cyanate or, if the oxidation is complete, nitrogen and hydrogen.
Ifølge en annen kjent fremgangsmåte overføres cyanidet i en miljøvennligere form ved å utfelle denne ferrosalter, enten som bérlinblått eller -hvitt. Førstnevnte spaltes så etter hvert under basiske forhold tilbake til cyanid, men utfelling derav til berlinhvitt igjen ikke lar seg utføre kvantitativt, idet et temmelig høyt restinnhold av cyanid blir tilbake i cyanidløs-ningen. According to another known method, the cyanide is transferred in a more environmentally friendly form by precipitating this ferrous salt, either as Berlin blue or -white. The former is then gradually decomposed under basic conditions back to cyanide, but its precipitation to Berlin white again cannot be carried out quantitatively, as a rather high residual content of cyanide remains in the cyanide solution.
Andre behandlingsmetoder for cyanidholdige vaskevannsløsninger Other treatment methods for cyanide-containing washing water solutions
i in
er katalytisk oksydasjon av cyanider i gassform med platina/ rodium-katalysator eller aktivt karbon. Oksydasjonen kan også utføres ved å elektrolysere konsentrert cyanidløsninger, hvorved sluttkonsentrasjonen normalt er ca. lg cyanid/l. is catalytic oxidation of cyanides in gaseous form with a platinum/rhodium catalyst or activated carbon. The oxidation can also be carried out by electrolysing concentrated cyanide solutions, whereby the final concentration is normally approx. lg cyanide/l.
Fra publikasjonen "Transactions of the ASME" januar 1960, From the publication "Transactions of the ASME" January 1960,
side 68-72 er det kjent for å fjerne cyanidgasser fra ovnsgasser og sirkulere en vaskeløsning hvis pH verdi er inn- pages 68-72, it is known to remove cyanide gases from furnace gases and circulate a washing solution whose pH value is in-
stilt på maksimalt 9,5. Innstillingen av pH verdien skjer derunder gjennom ovnsgassens karbondioksydandel. set to a maximum of 9.5. The setting of the pH value takes place below through the carbon dioxide proportion of the furnace gas.
I tysk utlegningsskrift 1546498 er det angitt en fremgangs- In German specification document 1546498, a progress
måte ved avgifting av cyanholdig avløpsvann, ved hvilken dette avløpsvann innstilles på en pH verdi på ca. 7 eller mindre før blåsyren som er tilstede deri drives ut med en gass. way in the detoxification of cyanide-containing waste water, whereby this waste water is adjusted to a pH value of approx. 7 or less before the hydrocyanic acid present therein is expelled with a gas.
Ulempene med de ovennevnte kjente metoder er enten høye kjemi-kalie- og investeringsomkostninger, en komplisert prosess The disadvantages of the above-mentioned known methods are either high chemical and investment costs, a complicated process
eller fremgangsmåten egner seg ikke for behandling av fortyn-nede cyanidløsninger som spesielt oppstår ved vasking av ovnsgasser. Felles for disse kjente metoder er dessuten at de hovedsaklig vedrører fjerning av cyanid som allerede er hav-net i vannet. or the method is not suitable for the treatment of diluted cyanide solutions which occur in particular when washing furnace gases. What these known methods also have in common is that they mainly concern the removal of cyanide that is already in the water.
Hensikten med foreliggende oppfinnelse er å unngå de ulemper The purpose of the present invention is to avoid those disadvantages
som er forbundet med ovennevnte tidligere kjente fremgangs-måter og tilveiebringe en fremgangsmåte for vasking av cyanidholdige ovnsgasser som dannes med metalurgisk industri hvor likevekten mellom ovnsgassene og vaskevannsløsningen reguleres slik at cyanidinnholdet til ovnsgassene senkes før vasken og dett holdes så lavt i vaskevannsløsningen at en adskilt fjerning av cyanid fra vaskevanns-løsningen ikke mer er nødvendig. Ved fremgangsmåten ifølge oppfinnelsen tilstre-ber man å holde tilbake en så stor del av cyanidene som mulig i ovnsgassene, hvilke gasser forbrennes etter vaskingen, hvorved også cyanidene spaltes til mindre skadelige forbindelser. which is connected with the above previously known methods and providing a method for washing cyanide-containing furnace gases which are formed with metallurgical industry where the equilibrium between the furnace gases and the washing water solution is regulated so that the cyanide content of the furnace gases is lowered before the washing and it is kept so low in the washing water solution that a separate removal of cyanide from the wash water solution no more is needed. In the method according to the invention, the aim is to retain as large a proportion of the cyanides as possible in the furnace gases, which gases are burned after washing, whereby the cyanides are also broken down into less harmful compounds.
Oppfinnelsen ligger i. gjenstanden for kravets karakteriser- The invention lies in the object of the claim's characterization
ende del. end part.
Ifølge oppfinnelsen reguleres cyanidlikevekten mellom ovnsgassen av vaskevannsløsningen ved å tilsette syre til den sirkule- According to the invention, the cyanide equilibrium between the furnace gas and the washing water solution is regulated by adding acid to the circulating
rende vaskevannsløsningen for å regulere vaskevannsløsningens surhet så lavt at en så stor del av cyanidene som mulig destrueres ved forbrenning av ovnsgassens brennbare forbihdelses-deler. på denné måten blir apparaturen som anvendes ved til-lempning av fremgangsmåten enkel og investeringsomkostningene små, og dessuten driftsomkostningene lave. Ovnsgassene inneholder så mye brennbare forbindelser at det er lønnsomt å ut-nytte deres varmeinnhold ved forbrenning av ovnsgassen etter vaskingen. Herved spaltes cyanidene i ovnsgassen til betydelig ufarligere forbrenningsprodukter. drain the wash water solution in order to regulate the acidity of the wash water solution so low that as large a part of the cyanides as possible is destroyed by burning the combustible parts of the furnace gas. in this way, the equipment used when applying the method is simple and the investment costs are small, and also the operating costs are low. The furnace gases contain so much flammable compounds that it is profitable to utilize their heat content by burning the furnace gas after washing. This breaks down the cyanides in the furnace gas into significantly less dangerous combustion products.
Den sirkulerende vaskevannsløsningens pH reguleres med fordel maksimalt til 9,5, eksempelvis maksimalt til 7,5. På grunn av at pH-verdien holdes på et lavere nivå enn vanlig oppløses og anrikes forskjellige forurensninger så som zink i vaskevannet. Forurensningsinnholdet av den sirkulerende vaske-vannsløsningen reguleres ved å fjerne en del av vaskevannet The pH of the circulating wash water solution is advantageously adjusted to a maximum of 9.5, for example a maximum of 7.5. Due to the fact that the pH value is kept at a lower level than usual, various contaminants such as zinc are dissolved and enriched in the wash water. The pollutant content of the circulating washing water solution is regulated by removing part of the washing water
og erstatte det med ferskvann. Forurensningene i vaskevannet som er adskilt fra omløpet utfelles ved å heve pH. Når vaske-vannsløsningens cyanidinnhold er lavt, kan den uten fare behan-dles for å fjerne forurensningene. and replace it with fresh water. The contaminants in the wash water that are separated from the circulation are precipitated by raising the pH. When the wash water solution's cyanide content is low, it can be safely treated to remove the contaminants.
Likevektsberegninger fer karbohdioksyd-, monoksyd-'og hydrogen-holdig ovnsgass viser at cyanidet forekommer som hydrogencya- Equilibrium calculations for carbon dioxide, monoxide and hydrogen-containing furnace gas show that the cyanide occurs as hydrogen cyanide
nid ved nærvær av vanndamp, hvis partialtrykk synker når oksygentrykket og temperaturen stiger. Herved blir det mulig å senke gassenes cyanidinnhold ved å øke gassenes oksygentrykk ved en høy temperatur før vaskingen. nid in the presence of water vapour, whose partial pressure decreases as the oxygen pressure and temperature rise. This makes it possible to lower the gas's cyanide content by increasing the gas's oxygen pressure at a high temperature before washing.
Den etterfølgende tabell viser likevektssammensetningen til The following table shows the equilibrium composition of
en ovnsgass for to forskjellige vanndampinnhold (A og B) a furnace gas for two different water vapor contents (A and B)
idet A=5 g/m<3> (273 K; 101,325 kPa) og B=20 g/m<3> (273 K; 101, where A=5 g/m<3> (273 K; 101.325 kPa) and B=20 g/m<3> (273 K; 101,
325 kPa) og ved forskjellige karbonmonoksydinnhold (CO-60, 325 kPa) and at different carbon monoxide contents (CO-60,
~90 og ~99 vol.-%) ved en temperatu på 1500 K. ~90 and ~99 vol.-%) at a temperature of 1500 K.
Med synkende temperatur stiger blåsyrens likevektsinnhold With decreasing temperature, the equilibrium content of hydrocyanic acid rises
slik at ovnsgassens blåsyreinnhold ved et lavt oksygentrykk (CO~99 vol.-%) er 0,012 vol.-% (for A) og 0,048 vol.-% so that the prussic acid content of the furnace gas at a low oxygen pressure (CO~99 vol.-%) is 0.012 vol.-% (for A) and 0.048 vol.-%
(for B). (for B).
Her får man den mulighet å senke gassens cyanidinnhold ved Here you get the opportunity to lower the cyanide content of the gas
å øke dens oksygenpartialtrykk ved høy temperatur før vaskingen. to increase its oxygen partial pressure at high temperature before washing.
Ved nærvær av kalium er cyanidet praktisk talt helt i kalium-cyanidform. Når oksygentrykket synker^ begynner cyanidet å foreligge mer i hydrogencyanidform, og ved lav temperatur og oksygentrykk (CO 80 %) foreligger cyanidet nesten helt i hydrogencyanidform. Når gassen inneholder kalium kan man gene-relt konstatere at oksygentrykket har liten innvirkning på forekomsten av cyanid med andre ord forekommer cyanidet all-tid i likevektsblandingen. In the presence of potassium, the cyanide is practically entirely in the potassium cyanide form. When the oxygen pressure drops^ the cyanide begins to exist more in hydrogen cyanide form, and at low temperature and oxygen pressure (CO 80%) the cyanide is almost entirely in hydrogen cyanide form. When the gas contains potassium, it can generally be established that the oxygen pressure has little effect on the occurrence of cyanide, in other words, the cyanide is always present in the equilibrium mixture.
Ved vasking av ovnsgasser avhenger cyanidinnholdet av vaske-vannsløsningens pH på følgende måte: When washing furnace gases, the cyanide content depends on the pH of the washing water solution in the following way:
Fra reaksjonsformelen From the reaction formula
får man approksimativt AGT° (J/mol) og one gets approximately AGT° (J/mol) and
hvor PHCN = cyanidens partialtrykk (bar) where PHCN = partial pressure of the cyanide (bar)
[cn"J "cyanidinnholdet i vaskevannet (mol/l) [cn"J "the cyanide content in the washing water (mol/l)
T = vasketemperaturen (K) T = washing temperature (K)
Ved konstant temperatur bestemmer vaskevannets cyanidinnhold og pH.hydrogencyanidets partialtrykk i den vaskede ovnsgassen. Med andre ord reguleres den utledede gassens cyanidinnhold slik at den er like stor som cyanidets partialtrykk i den inn-komne gassen ved å regulere vaskevannets pH. Jo lavere cyanidinnhold man ønsker i vaskevannet, jo lavere må pH- verdien være for at en viss cyanidmengde som kommer med ovnsgassen helt skal kunne føres gjennom vaskingen. At a constant temperature, the wash water's cyanide content and pH determine the hydrogen cyanide's partial pressure in the washed furnace gas. In other words, the cyanide content of the discharged gas is regulated so that it is equal to the partial pressure of the cyanide in the incoming gas by regulating the pH of the washing water. The lower the cyanide content you want in the washing water, the lower the pH value must be so that a certain amount of cyanide that comes with the furnace gas can be fully carried through the washing.
Følgende teoretiske eksempel belyser det ovennevnte: The following theoretical example illustrates the above:
Når ovnsgass hvis cyanidinnhold er 300 mg/m3 (0°C~; 101, 325 kPa) (0,024 volum-%, -2,4*10 <-4>bar), vaskes ved temperaturen' T = 27°C (300 K) og man ønsker å føre cyanidmengden helt gjennom vaskingen slik at vaskevannets cyanidinnhold ikke oversti--4 ger 10 mg/l (3,6*10 mol/1),, skal vaskevannets pH-verdi prin-sipielt, reguleres på følgende måte: When furnace gas whose cyanide content is 300 mg/m3 (0°C~; 101, 325 kPa) (0.024 volume-%, -2.4*10 <-4>bar), is washed at the temperature' T = 27°C (300 K) and you want to carry the amount of cyanide all the way through the wash so that the wash water's cyanide content does not exceed 10 mg/l (3.6*10 mol/1), the wash water's pH value must in principle be regulated in the following way :
Hvis cyanidinnholdet i det sirkulerende vaskevannet får stige til 100 mg/l får pH-verdien være 9,5. Ovnsgassens cyanidinnhold og hydrogencyanidets partialtrykk i vaskevannet når samme nivå innenfor pH-intervallet 7,5-9,5, hvis man ønsker å holde cyanidinnholdet i det sirkulerende vaskevannet på If the cyanide content in the circulating wash water is allowed to rise to 100 mg/l, the pH value must be 9.5. The cyanide content of the furnace gas and the hydrogen cyanide partial pressure in the wash water reach the same level within the pH interval 7.5-9.5, if one wishes to keep the cyanide content in the circulating wash water at
et middels nivå (10 mg/l) hvorved behandling av det sirkulerende vaskevannet, så som adskillelse av fast substans, ikke forårsaker helsefare. • Herved skulle ovsngassens cyanidinnhold mellom 30-3 000 mg/m3 kunne føres gjennom vaskingen, fig. 2. a medium level (10 mg/l) at which treatment of the circulating washing water, such as separation of solid matter, does not cause a health hazard. • In this way, the cyanide content of the furnace gas between 30-3,000 mg/m3 should be able to be passed through the washing, fig. 2.
Oppfinnelsen beskrives nærmere nedenfor under henvisning til vedlagte tegninger, hvor The invention is described in more detail below with reference to the attached drawings, where
fig. 1 viser en skjematisk projeksjon fra siden av en appara-tur som er ment for anvendelse ved fremgangsmåten ifølge oppfinnelsen fig. 1 shows a schematic projection from the side of an apparatus intended for use in the method according to the invention
og and
fig. 2 viser et diagram hvor vaskevannsløsningen cyanidinnholdet i mg/l er fremstilt som funksjon av vaskevannsløsningens pH og ovnsgassens cyanidinnhold (mg/m 3) ved en vasketemperatur på 27°C. fig. 2 shows a diagram where the cyanide content of the washing water solution in mg/l is plotted as a function of the pH of the washing water solution and the cyanide content of the furnace gas (mg/m 3 ) at a washing temperature of 27°C.
I fig. 1 som viser reguleringssystemet for vaskevannets CN-ni-vå har gasskrubberen fått henvisningstallet 1, til hvilken skrubber gassen fra ovnen føres langs rør 2. Vaskevannets pH reguleres ved å tilbakeføre vaskevann langs rør 3 til skrubberen, hvilket vann er tilsatt som i svovelsyre i blandingsbeholderen 4 at vaskevannets pH som kommer fra skrubberen gjennom røret 5 har den ønskede regulerte verdi. pH-verdien til vaskevannet måles i beholderen 6. Den mengde konsentrert svovelsyre som pumpes til blandingsbeholderen 4 fra beholderen 9 gjennom røret 10 reguleres ved hjelp av pH-måleren 7 og venti-len 8. Vannet som fordamper i skrubberen 1 og går bort som damp sammen med utløpsgassen via viften 19 gjennom røret 11 og vannet som fjernes sammen med den faste substansen fra sedementeringsbassenget 1-4 erstattes ved å tilsette vann i det sirkulerende vaskevannet gjennom røret 12. Vannet som går ut fra skrubberen 1 føres fra pH målingsbeholderen 6 gjennom røret 13 videre gjennom røret 16 til sedementeringsbassenget 14, hvor det faste stoffet sedementerer. Sedementeringen utføres ved å føre flokuleringsmiddelet eller kjemikaliet for pH-regu-lering og/eller utfelling til beholderen 17 gjennom røret 15. Den sedementerte faste substansen og de utfelte saltene fjernes fra omløpet gjennom røret 18 til en avløpssone og den klare løsningen innføres i kretsløpet gjennom røret 19. Om nødvendig kan vaskingen av gassen gjøres mer effektiv ved å koble 2 eller flere skrubbere i serie. In fig. 1 which shows the regulation system for the CN level of the wash water, the gas scrubber has been given the reference number 1, to which scrubber the gas from the furnace is fed along pipe 2. The pH of the wash water is regulated by returning wash water along pipe 3 to the scrubber, which water is added as in sulfuric acid in the mixing container 4 that the pH of the washing water coming from the scrubber through the pipe 5 has the desired regulated value. The pH value of the wash water is measured in the container 6. The amount of concentrated sulfuric acid that is pumped to the mixing container 4 from the container 9 through the pipe 10 is regulated with the help of the pH meter 7 and the valve 8. The water that evaporates in the scrubber 1 and goes away as steam together with the outlet gas via the fan 19 through the pipe 11 and the water that is removed together with the solid substance from the sedimentation basin 1-4 is replaced by adding water to the circulating wash water through the pipe 12. The water that comes out of the scrubber 1 is led from the pH measuring container 6 through the pipe 13 further through the pipe 16 to the sedimentation basin 14, where the solid material sediments. The sedimentation is carried out by feeding the flocculating agent or the chemical for pH regulation and/or precipitation to the container 17 through the pipe 15. The sedimented solid substance and the precipitated salts are removed from the circulation through the pipe 18 to a drain zone and the clear solution is introduced into the circuit through pipe 19. If necessary, the washing of the gas can be made more efficient by connecting 2 or more scrubbers in series.
EKSEMPEL EXAMPLE
Ovnsgassens oksygenpartialtrykk ble regulert ved hjelp av avluften ved en temperatur på 147 5 K slik at karbondioksyd-innholdet sank fra 95 vol.-% til 85 vol.-%. Gassens cyanidinnhold før reguleringen var 6 mg pr. m 3 (273 K; 101,325 kPa) hvilket tilsvarer ca. 0,005 vel.-%. Avluftens fuktighets^nn-hold var slik at gassens vanndampinnhold etter tilsetning av avluft ble 5 mg/m<3> (273 K; 101,325 kPa). Etter reguleringen avr cyanidinnholdet til gassen 0,5 mg/m 3 (273 K; 101,325 kPa), dvs. ca. 0,00004 vol.-%. The oxygen partial pressure of the furnace gas was regulated using the exhaust air at a temperature of 147 5 K so that the carbon dioxide content dropped from 95 vol.-% to 85 vol.-%. The cyanide content of the gas before the regulation was 6 mg per m 3 (273 K; 101.325 kPa) which corresponds to approx. 0.005 well.-%. The moisture content of the exhaust air was such that the water vapor content of the gas after the addition of exhaust air was 5 mg/m<3> (273 K; 101.325 kPa). After the regulation, the cyanide content of the gas is 0.5 mg/m 3 (273 K; 101.325 kPa), i.e. approx. 0.00004 vol.-%.
i in
Claims (1)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI790392A FI62040C (en) | 1979-02-06 | 1979-02-06 | PROCEDURE FOR THE FIELD OF THE METALLURGICAL INDUSTRY |
Publications (3)
Publication Number | Publication Date |
---|---|
NO800304L NO800304L (en) | 1980-08-07 |
NO149163B true NO149163B (en) | 1983-11-21 |
NO149163C NO149163C (en) | 1984-02-29 |
Family
ID=8512367
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
NO800304A NO149163C (en) | 1979-02-06 | 1980-02-05 | PROCEDURE FOR WASHING CYANIDE-CONTAINING OBAS GASES FROM THE METALLURGICAL INDUSTRY |
Country Status (11)
Country | Link |
---|---|
JP (1) | JPS598411B2 (en) |
AT (1) | AT375562B (en) |
BR (1) | BR8000654A (en) |
DE (1) | DE3004173C2 (en) |
FI (1) | FI62040C (en) |
FR (1) | FR2448382B1 (en) |
GB (1) | GB2043611B (en) |
IN (1) | IN151790B (en) |
NO (1) | NO149163C (en) |
SE (1) | SE437940B (en) |
ZA (1) | ZA80562B (en) |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1180909A (en) * | 1956-08-10 | 1959-06-10 | Rheinpreussen Ag | Process for removing hydrocyanic acid from industrial flue gases |
LU39849A1 (en) * | 1960-04-22 | 1961-05-02 | ||
DE1240230B (en) * | 1964-07-02 | 1967-05-11 | Strico Ges Fuer Metallurg | Process for purifying blast furnace gases |
FR1471715A (en) * | 1965-03-19 | 1967-05-10 | ||
JPS5638638B2 (en) * | 1971-10-18 | 1981-09-08 |
-
1979
- 1979-02-06 FI FI790392A patent/FI62040C/en not_active IP Right Cessation
-
1980
- 1980-01-30 ZA ZA00800562A patent/ZA80562B/en unknown
- 1980-02-01 BR BR8000654A patent/BR8000654A/en not_active IP Right Cessation
- 1980-02-01 AT AT0055580A patent/AT375562B/en not_active IP Right Cessation
- 1980-02-05 GB GB8003753A patent/GB2043611B/en not_active Expired
- 1980-02-05 NO NO800304A patent/NO149163C/en unknown
- 1980-02-05 SE SE8000919A patent/SE437940B/en not_active IP Right Cessation
- 1980-02-05 DE DE3004173A patent/DE3004173C2/en not_active Expired
- 1980-02-06 IN IN137/CAL/80A patent/IN151790B/en unknown
- 1980-02-06 JP JP55012545A patent/JPS598411B2/en not_active Expired
- 1980-02-06 FR FR8002883A patent/FR2448382B1/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
NO800304L (en) | 1980-08-07 |
GB2043611A (en) | 1980-10-08 |
JPS598411B2 (en) | 1984-02-24 |
FI62040C (en) | 1982-11-10 |
AT375562B (en) | 1984-08-27 |
GB2043611B (en) | 1983-01-12 |
FR2448382A1 (en) | 1980-09-05 |
NO149163C (en) | 1984-02-29 |
IN151790B (en) | 1983-07-30 |
ATA55580A (en) | 1984-01-15 |
SE437940B (en) | 1985-03-25 |
FI790392A (en) | 1980-08-07 |
ZA80562B (en) | 1981-02-25 |
DE3004173A1 (en) | 1980-08-07 |
SE8000919L (en) | 1980-08-07 |
JPS55106525A (en) | 1980-08-15 |
BR8000654A (en) | 1980-10-14 |
FI62040B (en) | 1982-07-30 |
FR2448382B1 (en) | 1988-01-29 |
DE3004173C2 (en) | 1981-12-17 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
TWI430833B (en) | Treatment of waste gas | |
AU3015899A (en) | Removal of NOx and SOx emissions from pickling lines for metal treatment | |
US4056469A (en) | Purification of waste water from hydrazine production | |
US4160730A (en) | Process for mercury removal | |
US5348724A (en) | Method of decomposing hydrogen peroxide | |
US5667760A (en) | Methods for sweetening hydrocarbons | |
NO149163B (en) | PROCEDURE FOR WASHING CYANIDE-CONTAINING OBAS GASES FROM THE METALLURGICAL INDUSTRY | |
US1931408A (en) | Washing of flue gases from combustion furnaces and the like | |
CA1258565A (en) | Process for purifying industrial gases and industrial flue gases | |
US2132592A (en) | Disposal of ammonia liquor | |
KR100216569B1 (en) | Method for measuring oxidation-reduction potential in a flue gas desulfurization process | |
US2745714A (en) | Treatment of odor containing gases with chlorine dioxide | |
US5120451A (en) | Process for reducing the cyanide content of a solution | |
AU645203B2 (en) | Process for the separation of hydrogen cyanide from gases and waste gases | |
NO158996B (en) | PROCEDURE FOR CLEANING OF CYANIDE-CONTAINING GAS WASHING WATER FROM THE METALLURGICAL INDUSTRY. | |
EP0564115A1 (en) | Method of monitoring pH in caustic liquor wet oxidation | |
JP6152751B2 (en) | Method of treating low-concentration cyanide-containing water containing iron cyano complex | |
RU2253626C1 (en) | Method of purification of sewage from ions of ammonium | |
CA1119004A (en) | Process for mercury removal | |
JPS63232897A (en) | Ozone treating device for distillate water in cyanogen concentrator | |
JPS61227905A (en) | Denitration of concentrated sulfuric acid | |
SU304966A1 (en) | METHOD FOR CLEANING GAS FROM MERCURY STEAMS | |
CN117985892A (en) | Cyanide-containing wastewater treatment method | |
JPH05115887A (en) | Treatment for waste water containing inorganic sulfur-containing compound | |
Henry | Hydrogen Sulfide in Sludge Gas |