GB838703A - Improvements relating to the cleaning of gases from aluminium furnaces and to the recovery of fluorine values therefrom - Google Patents

Improvements relating to the cleaning of gases from aluminium furnaces and to the recovery of fluorine values therefrom

Info

Publication number
GB838703A
GB838703A GB1578256A GB1578256A GB838703A GB 838703 A GB838703 A GB 838703A GB 1578256 A GB1578256 A GB 1578256A GB 1578256 A GB1578256 A GB 1578256A GB 838703 A GB838703 A GB 838703A
Authority
GB
United Kingdom
Prior art keywords
liquid
fluoride
gases
washing
precipitated
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB1578256A
Inventor
Kristian Fredrik Langfel Ramse
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.)
Elektrokemisk AS
Original Assignee
Elektrokemisk AS
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
Application filed by Elektrokemisk AS filed Critical Elektrokemisk AS
Publication of GB838703A publication Critical patent/GB838703A/en
Expired legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • C25C3/22—Collecting emitted gases
    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B7/00—Halogens; Halogen acids
    • C01B7/19—Fluorine; Hydrogen fluoride
    • C01B7/191—Hydrogen fluoride

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Environmental & Geological Engineering (AREA)
  • Biomedical Technology (AREA)
  • Health & Medical Sciences (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Inorganic Chemistry (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Treating Waste Gases (AREA)

Abstract

The fluorine content is recovered from electrolytic aluminium furnace gases by washing the gases with a continuous circulation of an aqueous HF-absorbing liquid, precipitating fluoride in the used washing liquid, and recirculating the used washing liquid, with or without precipitate, and controlling the pH value of the washing liquid to less than 7, preferably less than 5. The liquid may be in continuous circulation in a closed system washing plant and fluorine-containing material may be precipitated in the circulating system itself and continuously, or intermittently, separated. Alternatively, a proportion of the circulating liquid may be continuously, or intermittently, withdrawn, fluorine-containing material precipitated in a separate system, and residual liquid returned to the circulating system. The precipitant may be included in the circulating liquid, or continuously, or intermittently added thereto. The washing liquid may contain, or have added thereto, soda, or other alkali metal hydroxides, or carbonates, in such restricted quantity that acid sodium fluoride is formed. Sodium aluminium fluoride is precipitated from the resulting saturated fluoride solution: (1) by aluminium fluoride; (2) by sodium aluminate and bicarbonate; or (3) sodium aluminate and carbon dioxide. In reactions (2) and (3) the regenerated liquid, which contains soda, is only added to existing wash liquid in accordance with the soda consumption therein. Pure water may be used as washing liquid and sodium aluminium fluoride may be precipitated from the resulting HF solution by sodium aluminate. The sulphurous content of the gases may be removed subsequently by passage through an irrigated limestone tower.
GB1578256A 1956-04-30 1956-05-22 Improvements relating to the cleaning of gases from aluminium furnaces and to the recovery of fluorine values therefrom Expired GB838703A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH3271056A CH368628A (en) 1956-04-30 1956-04-30 Process for separating fluorine from exhaust gases

Publications (1)

Publication Number Publication Date
GB838703A true GB838703A (en) 1960-06-22

Family

ID=4500470

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1578256A Expired GB838703A (en) 1956-04-30 1956-05-22 Improvements relating to the cleaning of gases from aluminium furnaces and to the recovery of fluorine values therefrom

Country Status (2)

Country Link
CH (1) CH368628A (en)
GB (1) GB838703A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3132921A (en) * 1961-02-24 1964-05-12 Electro Chimie Metal Process for production of cryolite from fluorinated compounds in gases
US3660019A (en) * 1969-02-01 1972-05-02 Universal Oil Prod Co Process for purifying industrial waste gases containing fluorine values

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3322659A (en) * 1964-06-17 1967-05-30 Paquet Jean Louis Treating of electrolytic aluminum reduction cell gases to recover fluorine values

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3132921A (en) * 1961-02-24 1964-05-12 Electro Chimie Metal Process for production of cryolite from fluorinated compounds in gases
US3660019A (en) * 1969-02-01 1972-05-02 Universal Oil Prod Co Process for purifying industrial waste gases containing fluorine values

Also Published As

Publication number Publication date
CH368628A (en) 1963-04-15

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