NO313992B1 - Process for the evaporation of spent sulfuric acid - Google Patents
Process for the evaporation of spent sulfuric acidInfo
- Publication number
- NO313992B1 NO313992B1 NO19950440A NO950440A NO313992B1 NO 313992 B1 NO313992 B1 NO 313992B1 NO 19950440 A NO19950440 A NO 19950440A NO 950440 A NO950440 A NO 950440A NO 313992 B1 NO313992 B1 NO 313992B1
- Authority
- NO
- Norway
- Prior art keywords
- sulfuric acid
- evaporation
- finely divided
- weight
- less
- Prior art date
Links
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 title claims description 40
- 238000001704 evaporation Methods 0.000 title claims description 22
- 230000008020 evaporation Effects 0.000 title claims description 21
- 238000000034 method Methods 0.000 title claims description 14
- 239000007787 solid Substances 0.000 claims description 16
- 239000002253 acid Substances 0.000 claims description 7
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 5
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 4
- 229910052751 metal Inorganic materials 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- 229910052925 anhydrite Inorganic materials 0.000 claims description 3
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims description 3
- 238000003776 cleavage reaction Methods 0.000 claims description 3
- 230000007017 scission Effects 0.000 claims description 3
- 239000010936 titanium Substances 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 2
- 239000002994 raw material Substances 0.000 claims description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims 1
- 238000009835 boiling Methods 0.000 claims 1
- 229910052717 sulfur Inorganic materials 0.000 claims 1
- 239000011593 sulfur Substances 0.000 claims 1
- 238000000576 coating method Methods 0.000 description 7
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 2
- 230000029087 digestion Effects 0.000 description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 2
- 239000004408 titanium dioxide Substances 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 150000003464 sulfur compounds Chemical class 0.000 description 1
- 229910021653 sulphate ion Inorganic materials 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/88—Concentration of sulfuric acid
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Physical Vapour Deposition (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Heat Treatment Of Water, Waste Water Or Sewage (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Description
Foreliggende oppfinnelse angår en fremgangsmåte for inndamping av fortynnet brukt svovelsyre under unngåelse av inkrustasjon av varmeovergangsflater og apparatvegger med uoppløselige forbindelser. The present invention relates to a method for evaporating diluted used sulfuric acid while avoiding incrustation of heat transfer surfaces and apparatus walls with insoluble compounds.
Brukt svovelsyre må av økologiske grunner og for gjenvinning av de dannede verdifulle svovelforbindelser vanligvis opparbeides. De for dette kjente fremgangsmåtene (EP-A 22.181, EP-A 133.505) er omstendelige og gir først og fremst en stor økonomisk belastning for den forårsakende produk-sjonen, når konsentrasjonen av den brukte syren er lav. Spesielt ved de såkalte tynnsyrene, som de som dannes ved titandioksydproduksjon, i beiserekker, ved fremstillingen av organiske forbindelser og andre prosesser, med HgSO^-konsentrasjoner mellom 10 og 50 vekt-56, opptrer ofte det problem at det i anlegg med indirekte tilførsel av fordampingsvarme over varmevekseloverflater under inndampingen skjer dannelse av kvasiuoppløselige belegg på varmeovergangs-flåtene og de produktberørte apparatdelene. Ifølge DE-A 2.807.380 skal dette problemet unngås ved at inndampingen skjer i nærvær av minst 2 vekt-?6 FeS04. H2O. På grunn av den gode oppløseligheten av FeS04i fortynnet svovelsyre, er høye FeSO^-konsentrasjoner og/eller høye svovelsyrekonsentrasjoner nødvendig under inndampingen for realisering av den fore-slåtte fremgangsmåten. Det gir altså store innskrenkninger hva angår prosessparametrene. Dessuten unngås beleggdannelsen ikke helt. Det blir imidlertid innarbeidet vannoppløselig FeS04. H2O i belegget, slik at de uoppløselige beleggskom-ponentene kan fjernes som slam ved spyling av anlegget. Dette gir allerede en vesentlig lettelse, da den mekaniske fjerningen av uoppløselige belegg er svært problematisk og tidkrevende. Used sulfuric acid must usually be processed for ecological reasons and to recover the valuable sulfur compounds formed. The methods known for this (EP-A 22,181, EP-A 133,505) are cumbersome and primarily result in a large financial burden for the responsible production, when the concentration of the acid used is low. Especially with the so-called thin acids, such as those formed during titanium dioxide production, in pickling lines, during the production of organic compounds and other processes, with HgSO^ concentrations between 10 and 50 weight-56, the problem often arises that in plants with indirect supply of heat of vaporization over heat exchange surfaces during evaporation, formation of quasi-insoluble coatings occurs on the heat transfer rafts and the product-touched device parts. According to DE-A 2,807,380, this problem is to be avoided by the evaporation taking place in the presence of at least 2 wt-?6 FeS04. H2O. Due to the good solubility of FeSO4 in dilute sulfuric acid, high FeSO4 concentrations and/or high sulfuric acid concentrations are necessary during the evaporation to realize the proposed method. This therefore results in major restrictions with regard to the process parameters. Moreover, the formation of deposits is not completely avoided. However, water-soluble FeS04 is incorporated. H2O in the coating, so that the insoluble coating components can be removed as sludge when flushing the system. This already provides a significant relief, as the mechanical removal of insoluble coatings is very problematic and time-consuming.
Målet ved foreliggende oppfinnelse var således å fremskaffe en fremgangsmåte som muliggjør oppkonsentrering av fortynnet brukt svovelsyre ved inndamping uten at derved varmeover- gangsflatene og spesielle apparatdeler blir dekket med uoppløselige forbindelser. The aim of the present invention was thus to provide a method which enables the concentration of diluted used sulfuric acid by evaporation without thereby covering the heat transfer surfaces and special apparatus parts with insoluble compounds.
Det er overraskende funnet at fraskillelsen av uoppløselige belegg under inndampingen av brukt svovelsyre, kan unngås uten påvirkning av prosessen ved at indampingen av den brukte syren skjer i nærvær av finfordelte, uoppløselige, eller tungt oppløselige, faststoffer. Dette faststoffet kan enten bli suspendert før inndamping av den brukte syren, eller kan tilføres separat i det første inndampingstrinnet. Spesielt egnet er Fe203, den som avbrann kjente oksydblandingen som dannes ved termisk metallsulfatspaltning, T102, rester fra titanmalmoppslutning, SiCtø og/eller anhydritt (CaSO^. For å unngå avleiringer og oppnå en høy virksomhet, bør kornstør-relsen være mindre enn 10 \ im, fortrinnsvis stort sett mindre enn 2 pm. It has surprisingly been found that the separation of insoluble coatings during the evaporation of used sulfuric acid can be avoided without affecting the process by the evaporation of the used acid taking place in the presence of finely divided, insoluble, or poorly soluble, solids. This solid can either be suspended before evaporation of the spent acid, or can be added separately in the first evaporation step. Particularly suitable are Fe2O3, the known oxide mixture formed by thermal metal sulphate decomposition, T102, residues from titanium ore digestion, SiCt0 and/or anhydrite (CaSO^. To avoid deposits and achieve a high activity, the grain size should be less than 10 \ im, preferably mostly less than 2 pm.
Vesentlig for oppfinnelsens fremgangsmåte, er at de uopplø-selige eller tungt oppløselige fint fordelte faststoffene er suspendert i inndampingstrinnene i svovelsyren som skal inndampes. Dessuten må svovelsyren inneholde mindre enn 2 vekt-SÉ fast FeS04• R^O. Under inndampingsbetingelsene, hvor det foreligger 2 vekt-# eller mer fast FeS04• H2O i syren, gir de tilsatte faststoffene ifølge oppfinnelsen ingen ytterligere fordeler, men heller ingen ulemper. It is essential for the method of the invention that the insoluble or poorly soluble finely divided solids are suspended in the evaporation steps in the sulfuric acid to be evaporated. In addition, the sulfuric acid must contain less than 2 weight-SÉ solid FeS04• R^O. Under the evaporation conditions, where there are 2 wt-# or more solid FeS04 • H2O in the acid, the added solids according to the invention provide no further advantages, but also no disadvantages.
Gjenstand for oppfinnelsen er således en fremgangsmåte for flertrinns inndamping av brukt svovelsyre med en svovelsyre-konsentrasjon på 10 til 50 vekt-56 under indirekte tilførsel av fordampingsvarme over varmeveksleflater, kjennetegnet ved at inndampingen av den brukte svovelsyren blir gjennomført i nærvær av uoppløselig eller tungt oppløselig, finfordelt faststoff med kornstørrelse under 10 jjm, fortrinnsvis under 2 pm, hvorved mindre enn 0,1 vekt-96 finfordelt faststoff foreligger suspendert i den brukte svovelsyren som skal inndampes. The object of the invention is thus a method for multi-stage evaporation of spent sulfuric acid with a sulfuric acid concentration of 10 to 50 wt-56 under indirect supply of evaporation heat over heat exchange surfaces, characterized by the evaporation of the spent sulfuric acid being carried out in the presence of insoluble or poorly soluble , finely divided solid with a grain size below 10 µm, preferably below 2 µm, whereby less than 0.1 weight-96 of finely divided solid is present suspended in the used sulfuric acid to be evaporated.
Spesielt foretrukket blir det som fintfordelt faststoff benyttet Fe20g, TiOa. S102, anhydritt, avbrann av metallsulfatspalting og/eller rest fra titanråstoffoppslutning. Particularly preferably, Fe20g, TiOa are used as finely divided solids. S102, anhydrite, combustion of metal sulfate cleavage and/or residue from titanium raw material digestion.
Det finfordelte faststoffet foreligger fortrinnsvis i mengder på mindre enn 0,1 vekt-56 i den brukte svovelsyren som skal inndampes, spesielt foretrukket i mengder fra 0,002 til 0,03 vekt-#. The finely divided solid is preferably present in amounts of less than 0.1 wt-56 in the used sulfuric acid to be evaporated, particularly preferably in amounts of from 0.002 to 0.03 wt-#.
Det finfordelte faststoffet blir fortrinnsvis tilført i det første inndampingstrinnet i mengder på mindre enn 0,1 vekt-56, fortrinnsvis 0,002 til 0,03 vekt-#, av mengden brukt svovelsyre som blir tilført dette inndampingstrinnet. The finely divided solid is preferably added to the first evaporation stage in amounts of less than 0.1 wt-56, preferably 0.002 to 0.03 wt-#, of the amount of spent sulfuric acid which is fed to this evaporation stage.
Ved tilsetting av 0,002 vekt-?É av den fineste avbrannfrak-sjonen fra metallsulfatspalting, hvis kornstørrelse gjennom-snittlig er 0,2 pm, kan eksempelvis i løpet av fire ukers forsøkstid, dannelsen av uoppløselig belegg i det første trinnet i et 3-trinns vakuuminndampingsanlegg for konsen-trer ing av tynnsyre fra titandioksydproduksjonen, unngås fullstendig, mens det i et parallelt anlegg i det samme tidsrom blir utskilt et ca. 1 til 2 mm tykt Sit^-belegg, hvorved spesielt varmeovergangen og strømningsforholdene i rørvarmeveksleren påvirkes. By adding 0.002 weight-?É of the finest burn-off fraction from metal sulfate cleavage, whose grain size is on average 0.2 pm, for example during a four-week trial period, the formation of an insoluble coating in the first step of a 3-stage vacuum evaporation plant for concentrating thin acid from titanium dioxide production is completely avoided, while in a parallel plant, in the same period of time, an approx. 1 to 2 mm thick Sit^ coating, whereby the heat transition and flow conditions in the tube heat exchanger are particularly affected.
Claims (4)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4403841A DE4403841C2 (en) | 1994-02-08 | 1994-02-08 | Process for evaporating used sulfuric acid |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| NO950440D0 NO950440D0 (en) | 1995-02-07 |
| NO950440L NO950440L (en) | 1995-08-09 |
| NO313992B1 true NO313992B1 (en) | 2003-01-13 |
Family
ID=6509723
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NO19950440A NO313992B1 (en) | 1994-02-08 | 1995-02-07 | Process for the evaporation of spent sulfuric acid |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0666240B1 (en) |
| BR (1) | BR9500459A (en) |
| DE (2) | DE4403841C2 (en) |
| ES (1) | ES2134962T3 (en) |
| FI (1) | FI114091B (en) |
| NO (1) | NO313992B1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100581994C (en) * | 2008-01-09 | 2010-01-20 | 龚家竹 | Concentrating and impurity removing method for dilute sulfuric acid in titanium dioxide powder production process by employing sulfuric acid process |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT343062B (en) * | 1976-03-26 | 1978-05-10 | Oesterr Studien Atomenergie | PROCESS FOR CONTRACTING AND DRYING WATER CONTAINING FLOWABLE MEDIA |
| IT1086096B (en) * | 1977-09-21 | 1985-05-28 | Montedison Spa | PROCEDURE FOR THE CONCENTRATION OF AQUEOUS SOLUTIONS OF SULFURIC ACID |
| EP0022181B1 (en) * | 1979-06-13 | 1983-10-12 | Bayer Ag | Process and apparatus for regenerating sulfuric acid |
| DE3736111A1 (en) * | 1987-10-26 | 1989-05-03 | Kronos Titan Gmbh | METHOD FOR THE ENERGY-SAVING AND MATERIAL-SAVING RENEWAL OF THE DUENOUS ACID INVOLVED IN TITANIUM OXIDE MANUFACTURE AFTER THE SULPHATE PROCESS |
| DE3938915C1 (en) * | 1989-11-24 | 1991-05-08 | Bayer Ag, 5090 Leverkusen, De |
-
1994
- 1994-02-08 DE DE4403841A patent/DE4403841C2/en not_active Expired - Fee Related
-
1995
- 1995-01-26 EP EP95101051A patent/EP0666240B1/en not_active Expired - Lifetime
- 1995-01-26 ES ES95101051T patent/ES2134962T3/en not_active Expired - Lifetime
- 1995-01-26 DE DE59506290T patent/DE59506290D1/en not_active Expired - Fee Related
- 1995-02-06 FI FI950506A patent/FI114091B/en not_active IP Right Cessation
- 1995-02-07 BR BR9500459A patent/BR9500459A/en not_active IP Right Cessation
- 1995-02-07 NO NO19950440A patent/NO313992B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| FI950506A0 (en) | 1995-02-06 |
| EP0666240B1 (en) | 1999-06-30 |
| DE4403841A1 (en) | 1995-08-10 |
| DE4403841C2 (en) | 1997-12-04 |
| FI950506A (en) | 1995-08-09 |
| EP0666240A1 (en) | 1995-08-09 |
| NO950440L (en) | 1995-08-09 |
| DE59506290D1 (en) | 1999-08-05 |
| FI114091B (en) | 2004-08-13 |
| BR9500459A (en) | 1995-10-17 |
| ES2134962T3 (en) | 1999-10-16 |
| NO950440D0 (en) | 1995-02-07 |
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|---|---|---|---|
| MM1K | Lapsed by not paying the annual fees |