EP0843587A1 - Procede permettant de reduire la teneur en dioxine et en furane dans des gaz brules de fours et utilisation des poussieres de filtrage produites a cette occasion - Google Patents

Procede permettant de reduire la teneur en dioxine et en furane dans des gaz brules de fours et utilisation des poussieres de filtrage produites a cette occasion

Info

Publication number
EP0843587A1
EP0843587A1 EP96927659A EP96927659A EP0843587A1 EP 0843587 A1 EP0843587 A1 EP 0843587A1 EP 96927659 A EP96927659 A EP 96927659A EP 96927659 A EP96927659 A EP 96927659A EP 0843587 A1 EP0843587 A1 EP 0843587A1
Authority
EP
European Patent Office
Prior art keywords
alkali compound
filter
approx
injected
dioxin
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.)
Ceased
Application number
EP96927659A
Other languages
German (de)
English (en)
Inventor
Reiner Brockhoff
Klaus Hartmann
Jens HÖLTJE
Hans-Jürgen KORTE
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Solvay Soda Deutschland GmbH
Original Assignee
Solvay Alkali GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from DE1996121492 external-priority patent/DE19621492A1/de
Application filed by Solvay Alkali GmbH filed Critical Solvay Alkali GmbH
Publication of EP0843587A1 publication Critical patent/EP0843587A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/68—Halogens or halogen compounds
    • B01D53/70—Organic halogen compounds
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B21/00—Obtaining aluminium
    • C22B21/0084—Obtaining aluminium melting and handling molten aluminium
    • C22B21/0092—Remelting scrap, skimmings or any secondary source aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/02—Working-up flue dust
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/30—Alkali metal compounds
    • B01D2251/304—Alkali metal compounds of sodium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/60—Inorganic bases or salts
    • B01D2251/606—Carbonates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/10—Inorganic adsorbents
    • B01D2253/102—Carbon
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S75/00—Specialized metallurgical processes, compositions for use therein, consolidated metal powder compositions, and loose metal particulate mixtures
    • Y10S75/961—Treating flue dust to obtain metal other than by consolidation

Definitions

  • the invention relates to a method for cleaning furnace exhaust gases from melting, remelting or combustion plants, and to the use of the filter dusts which are produced in the process.
  • the invention is used in particular in the manufacture or processing of non-ferrous metals, the filter dusts being returned to the melting process.
  • a disadvantage of the known processes is that the removal rate of the dioxins and furans often does not meet the requirements.
  • the resulting filter dust is usually deposited.
  • melting aids e.g. B. salt salts and energy supplied.
  • Metal, slag, e.g. B. salt slag, and pollutant and dust-containing exhaust gases leave the production process.
  • the quantities of slag obtained are either processed for landfill or deposited.
  • the exhaust gases are primarily freed of dust, sulfur dioxide, HCl and HF. Methods are usually used for this, in which u. a. Quicklime or calcium hydroxide can be used. The resulting filter dust is deposited.
  • furnace types are used for the production of cast aluminum alloys, which are heated electrically or with gas or oil.
  • the rotary drum oven is widespread. It is particularly suitable for melting contaminated aluminum waste, shavings and other small-sized materials, but especially for starting materials with low yield.
  • the melting of the aluminum-containing scrap (aluminum waste, aluminum chips, aluminum dross, etc.) in the rotary drum furnace usually takes place under a closed salt blanket.
  • the purpose of the salt is to prevent oxidation of the aluminum, to bind the non-metallic impurities in the metal-containing insert and to facilitate the detachment of oxide layers from the base metal.
  • the salt from which the salt layer is formed consists of approx. 70% NaCl, approx. 30% KC1 and approx. 5% flux.
  • the process temperatures are between 600 ° C and 900 ° C depending on the alloy.
  • Fossil fuels are used as energy sources.
  • the exhaust gas stream also contains S0 2 , the composition of the exhaust gas constituents depending on the materials to be melted and the heating medium being able to vary.
  • sublimed alkali metal chlorides and fluorides, aluminum oxide and small amounts of heavy metals, aluminum in metallic form and free and organically bound carbon, inter alia in the form of dibenzodioxins and furans (PCDD / F) are contained in the exhaust gas. Both the exhaust gas and the salt slag obtained must be freed from the pollutants.
  • the salt slag can be processed by the dissolving process in such a way that the cleaned mixed salt is used again as the top salt in the rotary drum furnace.
  • the insoluble sediments (alumina residue) remaining after the dissolving process are processed further.
  • the exhaust gases which contain environmentally harmful components, are currently freed from undesired components in exhaust gas purification systems.
  • the exhaust gases are usually treated in a dry process at approx. 100 to 350 ° C with Ca (OH) 2 as sorbent, with free chlorine, HCl. HF and S0 2 react to CaCl 2 , CaF 2 and CaS0 4 .
  • the dioxins and furans are bound by adsorption.
  • At least one alkali compound is introduced into the exhaust gas, if appropriate in the presence of activated carbon and / or stove coke, and the filter dust is returned to a melting or combustion process.
  • Sodium carbonate, sodium hydrogen carbonate, sodium hydroxide, potassium carbonate, potassium hydroxide, potassium hydrogen carbonate are used alone or as a mixture as the alkali compound. If technical mixtures are used, impurities e.g. B. on alkaline earth compounds in the range of ⁇ 5% are accepted without the essence of the invention being impaired.
  • the activated carbon and / or the hearth furnace coke can either be separated or introduced into the exhaust gas stream in a mixture with the alkali compound.
  • sodium hydrogen carbonate which has an average particle size of 1 to 100 ⁇ m, preferably 5 to 40 ⁇ m, in particular 10 to 35 ⁇ m, is sprayed dry into a reactor or into the flue gas duct, preferably against the direction of flow, and mixed with the flue gases mixes.
  • the residence time in the flue gas is at least 0.5 seconds, preferably more than 2 seconds. During this time, the reaction of the harmful substances takes place e.g. B. to NaCl, NaF and Na 2 S0 4 .
  • technical grade sodium hydrogen carbonate was used, which has the following composition:
  • the effect of the alkali compound can be improved by adding activated carbon and / or stove coke.
  • the dioxins and furans are adsorbed.
  • the concentration of HCl in the clean gas is usually chosen as a guideline for the amount of additive added.
  • HCl is the main pollutant that is separated with sodium bicarbonate. Due to the fluctuations in the raw gas values that occur during operation, the amount of additive required cannot be clearly defined.
  • the amount of additive actually used therefore depends on the amount of pollutant actually to be separated. For example, about 8 to 12 kg of additive are used per ton of aluminum.
  • An optimized amount of additive is particularly important with regard to the return of the filter dust to the aluminum melt.
  • Sodium hydrogen carbonate not reacted with pollutants decomposes to sodium carbonate. Too high a proportion of sodium carbonate in the salt can lead to aluminum losses in the melting process. For economic reasons, however, aluminum losses are to be kept as low as possible.
  • the minimum reaction temperature for flue gas cleaning is approx. 70 to approx. 500 ° C, preferably between 90 and 280 ° C.
  • the gas stream, the z. B. contains sodium chloride, sodium sulfate and sodium carbonate happens z. B. a fabric filter in which the solids are separated.
  • the separated filter dust from the flue gas cleaning largely contains NaCl as well as small amounts of e.g. B. Sodium sulfate, sodium fluoride and additive components not reacted with pollutants.
  • the dioxins and furans contained in the flue gas cleaning residues are destroyed on the one hand by carrying out the reaction in the melting furnace. Furthermore, the returned filter dust suppresses the formation and / or decomposition of already formed dioxins and furans.
  • Another positive aspect is that the amount of additive required can be reduced in comparison with hydrated lime as an additive for flue gas cleaning. For example, only about 30 to 60% by weight of the usual amounts of additives are required.
  • Another advantage of the method according to the invention is the possibility of using the alkali metal compounds formed in further processes, e.g. B. the use of sodium compounds as sodium carriers or as additives for a wide variety of processes. It is also within the meaning of the invention to exhaust gases from other production processes, e.g. B. incinerators, analogous to the process described above by dry injection of z. B. sodium bicarbonate, if necessary in the presence of activated carbon and / or hearth coke, and the solid sodium compounds formed as a table salt for non-ferrous metal processing, e.g. B. Use aluminum scrap processing.
  • the melting process produces approx. 70,000 Nm 3 / h exhaust gas, which has the following pollutant contents:
  • the temperature of the exhaust gas when it enters the flue gas cleaning system is approximately 230 ° C.

Abstract

L'invention concerne un procédé permettant de purifier des gaz brûlés de fours d'installations de fusion, de refusion ou de combustion, ainsi que l'utilisation des poussières de filtrage produites à cette occasion. Cette invention s'utilise notamment pendant la production ou la préparation de métaux non ferreux. Selon l'invention, on injecte à sec au moins un composé alcalin, notamment du NaHCO3, éventuellement en présence de charbon actif et/ou de coke de four Martin, dans les gaz brûlés qui se dégagent du processus de production. La poussière de filtrage produite à cette occasion est renvoyée dans le processus de fusion ou de combustion. Etonnamment, il a été démontré que la poussière de filtrage ainsi renvoyée permettait d'abaisser la teneur en dioxine et en furane dans le gaz brut. La composition de la poussière de filtrage permet également de l'utiliser comme sel de recouvrement pour la production d'aluminium secondaire.
EP96927659A 1995-08-11 1996-08-02 Procede permettant de reduire la teneur en dioxine et en furane dans des gaz brules de fours et utilisation des poussieres de filtrage produites a cette occasion Ceased EP0843587A1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE19529649 1995-08-11
DE19529649 1995-08-11
DE19621492 1996-05-29
DE1996121492 DE19621492A1 (de) 1995-08-11 1996-05-29 Verfahren zur Verminderung des Dioxin- und Furangehaltes in Ofenabgasen und Nutzung der dabei anfallenden Filterstäube
PCT/EP1996/003407 WO1997006876A1 (fr) 1995-08-11 1996-08-02 Procede permettant de reduire la teneur en dioxine et en furane dans des gaz brules de fours et utilisation des poussieres de filtrage produites a cette occasion

Publications (1)

Publication Number Publication Date
EP0843587A1 true EP0843587A1 (fr) 1998-05-27

Family

ID=26017633

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96927659A Ceased EP0843587A1 (fr) 1995-08-11 1996-08-02 Procede permettant de reduire la teneur en dioxine et en furane dans des gaz brules de fours et utilisation des poussieres de filtrage produites a cette occasion

Country Status (5)

Country Link
US (1) US6077328A (fr)
EP (1) EP0843587A1 (fr)
CA (1) CA2225654A1 (fr)
RO (1) RO119693B1 (fr)
WO (1) WO1997006876A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SG68092A1 (en) * 1998-02-20 1999-10-19 Meidensha Electric Mfg Co Ltd Process and system for treating material containing noxious components
JP2001215007A (ja) * 1999-11-25 2001-08-10 Zeolite Kagaku Sangyo Kk ダイオキシン類を殆ど発生しないごみの焼却方法及びダイオキシン類発生抑制剤並びにその製造方法
ES2321550T3 (es) * 2006-12-18 2009-06-08 Befesa Aluminio Bilbao, S.L. Proceso de reciclado de polvos de filtro.
US11874173B1 (en) 2015-11-24 2024-01-16 Exergen Corporation Devices and methods for detecting inflammation
EP3960279A1 (fr) * 2020-09-01 2022-03-02 Primetals Technologies Austria GmbH Recirculation des matières valorisables de la purification de gaz d'échappement

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE294187C (fr) *
DE2056096B2 (de) * 1970-11-14 1978-09-28 Metallgesellschaft Ag, 6000 Frankfurt Verfahren zur Abtrennung von Fluorwasserstoff aus Gasen
US4065271A (en) * 1973-09-15 1977-12-27 Metallgesellschaft Aktiengesellschaft Process of separating hydrogen fluoride from gases
IT1126403B (it) * 1979-11-27 1986-05-21 Tonolli & C Spa A Procedimento e impianto per il lavaggio dei fumi e il recupero dei sali in un processo di produzione di alluminio secondario
SU899101A1 (ru) * 1980-06-12 1982-01-23 Донецкий Ордена Трудового Красного Знамени Политехнический Институт Способ очистки отход щих газов алюминиевого производства
DE3941894C2 (de) * 1989-12-19 1996-03-07 Steinmueller Gmbh L & C Verfahren zum Abscheiden organischer Schadstoffe aus einem Abgas
DE4109991C1 (fr) * 1991-03-27 1992-06-25 Metallwarenfabrik Stockach Gmbh, 7768 Stockach, De
US5364443A (en) * 1993-12-01 1994-11-15 Alcan International Limited Process for combined decoating and melting of aluminum scrap contaminated with organics
AT400007B (de) * 1994-04-06 1995-09-25 Austria Metall Verfahren zur reinigung von ofenabgasen und zur nutzung des dabei anfallenden filterstaubes

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9706876A1 *

Also Published As

Publication number Publication date
CA2225654A1 (fr) 1997-02-27
RO119693B1 (ro) 2005-02-28
WO1997006876A1 (fr) 1997-02-27
US6077328A (en) 2000-06-20

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