US3106448A - Recovery of cryolite - Google Patents

Recovery of cryolite Download PDF

Info

Publication number
US3106448A
US3106448A US100268A US10026861A US3106448A US 3106448 A US3106448 A US 3106448A US 100268 A US100268 A US 100268A US 10026861 A US10026861 A US 10026861A US 3106448 A US3106448 A US 3106448A
Authority
US
United States
Prior art keywords
cryolite
sodium
sodium carbonate
lining material
cell lining
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 - Lifetime
Application number
US100268A
Other languages
English (en)
Inventor
Whicher Charles Harry
Nickle Alexander Gordon
Dolega-Kowalewski An Krzysztof
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.)
Alcan Research and Development Ltd
Original Assignee
Aluminium Laboratories Ltd
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 Aluminium Laboratories Ltd filed Critical Aluminium Laboratories Ltd
Priority to US100268A priority Critical patent/US3106448A/en
Priority to SE3521/62A priority patent/SE310658B/xx
Priority to DEA39851A priority patent/DE1207362B/de
Priority to GB12548/62A priority patent/GB981243A/en
Priority to ES276075A priority patent/ES276075A1/es
Priority to CH399862A priority patent/CH409417A/fr
Priority to FR893149A priority patent/FR1324447A/fr
Application granted granted Critical
Publication of US3106448A publication Critical patent/US3106448A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • C25C3/18—Electrolytes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/04—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom
    • C01F7/08—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom by treating aluminous minerals with sodium carbonate, e.g. sinter processes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/48—Halides, with or without other cations besides aluminium
    • C01F7/50—Fluorides
    • C01F7/54—Double compounds containing both aluminium and alkali metals or alkaline-earth metals

Definitions

  • the electrolytic cell is made up of a sturdy steel outer shell and an inner lining of a heavy impervious layer of baked electrically conductive carbon which forms the cathode of the cell; to control heat losses the cell is usually insulated by a layer of insulating powder or brick ⁇ placed between the carbon lining and the external steel shell, Eventually, however, the carbon lining of the cell deteriorates with use due to the penetration of the electroly-tic bath and products of electrolysis resulting ultimately in warping and even the formation of fissures andcracks at which time the cell must be taken out of service and the lining replaced.
  • cryolite in the carbon cell lining particularly when it contains a substantial amount of cryolite admixed therein, such as an amount of cryolite in the range of Y10% to 30% by weight more or less.
  • cryolite values or the admixture of sodium fluoride (NaF) and aluminum fluoride (AlF'a) from the used carbonaceous lining.
  • fluoride values such as cryolite from the used carbonaceous cell lining material by treating nely divided cell material with an aqueous caustic solution to effect reaction between the iluoride values or cryolite therein with sodium hydroxide (NaOH) to yield water soluble sodium fluoride and water soluble sodium aluminate (NaAlO2) and then to treat the resulting-,solution to precipitate cryolite therefrom.
  • NaOH sodium hydroxide
  • NaAlO2 water soluble sodium aluminate
  • Still another object of this invention is to provide a process for the recovery of cryolite from carbonaceous Vcell lining material containing cryolite admixed therewith wherein improved yields of recovered cryolite are obtainable.
  • FIG. l is a How diagram or tlow chart illustrating various steps in the process of this invention.
  • FIG. 2 graphically illustrates the influence of lalreactant, sodium carbonate, employed in the process of this invention upon the solubility of fluoride-containing material and alumina in the cell lining material when treated in accordance with the practice of this invention.
  • carbonate is meant to include carbonate, bicarbonate and carbonate and bi- ⁇ carbonate-containing mixtures.
  • the precipitated cryolite is then separately recovered and may then be re-used in the electrolytic cell.
  • the reaction between cryolite-and the water-soluble carbonate, such as sodium carbonate, to yield Watersoluble sodium fluoride and sodium aluminate is carried out atan elevated temperature, such as a-temperature of about 500 C. or lower. Faster reaction rates are possible at higher temperatures; a satisfactory reaction rate is attainable at a temperature of about 800"V C. or even higher, such as a temperature of about 900 C. more or less. At about 900 C., however, the cell lining material being treated tends to become sticky and more difficult to handle.
  • rial is converted to sodium fluoride and sodium aluminate.
  • aqueous caustic solution containing less than about 1% by weight sodium hydroxide, eg. an amount of sodium hydroxide of about 2 grams per liter.
  • the resulting aqueous solution is then treated by contact with carbon dioxide, preferably gaseous carbon dioxide, to precipitate cryolite therefrom together with the formation of sodium car- -bonate which remains dissolved in the aqueous solution.
  • carbon dioxide preferably gaseous carbon dioxide
  • the resulting aqueous solution or spent liquor can then be treated for the recovery of sodium carbonate therefrom or employed directly to treat additional cell lining material for the recovery of cryolite therefrom.
  • FIG. 1 illustrates by way of a fiow chart, an embodiment of this invention directed to the recovery of cryolite from used carbonaceous Cryolite-containing cell lining material and from the solids which result from cleaning the gases escaping from the electrolytic cells.
  • the used carbonaceous cell lining material to be treated in accordance with this invention may have the chemical analysis set forth in the accompanying Table I.
  • the used cell lining material is supplied from a suitable source, not shown, by means of suitable solids handling equipment, not shown, via line to a crushing operation or crusher 11 wherein relatively large size or relatively massive pieces of the cell lining material are reduced to a smaller, more conveniently handled size.
  • a crushing operation or crusher 11 wherein relatively large size or relatively massive pieces of the cell lining material are reduced to a smaller, more conveniently handled size.
  • the resulting crushed cell lining material is supplied via line 12 to su-itable fine grinding equipment such as ball mill 14 wherein the already crushed cell lining material is reduced to a relatively fine size, such as a size below about minus 8 mesh. It is preferred, however, to carry out the grinding operation within ball mill 14 such that the resulting reduced cell lining material has a mesh size below about minus 35 mesh.
  • the smaller the size of the finely reduced cell lining material the faster the cell lining material (i.e., cryolite therein) reacts with the sodium carbonate in the subsequent roasting or high temperature conversion operation in accordance with this
  • the fine grinding of the cell lining material in ball mill 14 is carried out inthe presence of aqueous sodium carbonate-containing solution, such as aqueous sodium carbonate-containing spent liquor, supplied from a suitable source, not shown, via line 15.
  • aqueous sodium carbonate-containing solution such as aqueous sodium carbonate-containing spent liquor
  • the finely reduced cell lining particles are wetted with a film of aqueous sodium carbonate-containing solution which, upon drying, leaves a residue of sodium carbonate on these particles.
  • This coating or residue of sodium carbonate on the finely-divided cell lining particles serves to supply at least part of the process sodium carbonate requirements in the subsequent high temperature conversion or roasting operation.
  • filter 18 which may be a plate and frame filter or a continuous rotary vacuum filter.
  • the aqueous i sodium carbonate-containing filtrate recovered from filter 1S is recycled via line 17 to contact and to wet additional cell lining material undergoing size reduction in ball mill 14.
  • the filtered finely divided solids are removed from filter 18 and supplied Via line 19 to solids mixer 20 wherein these solids are mixed with a water soluble carbonate, such as a water soluble alkali metal carbonate, e.g. sodium carbonate or sodium bicarbonate or mixtures thereof.
  • a water soluble carbonate such as a water soluble alkali metal carbonate, e.g. sodium carbonate or sodium bicarbonate or mixtures thereof.
  • Sodium carbonate is preferred in the practice of this invention, ⁇ desirably dry, anhydrous sodium carbonate, which is supplied to mixer 20 from a suitable source, not shown, via line 23. It is mentioned, however, that instead of dry sodium carbonate, an aqueous slurry or a concentrated solution of sodium carbonate can be employed to supply all or a part of the sodium carbonate requirements of the high temperature conversion operation.
  • mixer 20 the finely divided cell lining material is thoroughly admixed with the sodium carbonate added thereto. Following Vthe solids mixing operation the resulting, substantially homogeneous admixture of cell lining material and sodium carbonate is supplied via line 21 to high temperature conversion or roasting zone or roaster 22.
  • Roaster 22 may comprise any suitable means or apparatus for effecting high temperature contact between a gas, such as an oxygen-containing gas, e.g. air, and the solids admixture supplied via line 21.
  • Roaster 22 may be a batch type roaster or continuously operating type roaster, ⁇ such as a rotating kiln or multihearth rabble arm roaster of the Herreshof type.
  • roaster 22 is a Herreshof type roaster, the solids rabbling contact afforded therein serving to promote good solid-solid contact between the soda carbonate and the cell lining material and also between the ⁇ oxygen-containing gas, air, supplied ⁇ fro-m a suitable source, not shown, via line 24 and the carbon or carbonaceous material in the cell lining material.
  • temperature control during the high temperature conversion or roasting operating can readily be effected by bleeding air into the furnace or by by-passing the furnace gases around any hearth. Temperature control during the roasting operation is desirable since cell lining material varies greatly as to carbon or carbonaceous material content. It is obvious, however, as indicated that many other types of roasters or kilns can be employed provided these are effective to provide a high temperature environment for the sodium carbonate and cryolite undergoing reaction.
  • the roaster off gases removed from roaster 22 via line 25 contain a substantial amount of gaseous carbon dioxide, about 20% by volume, more or less.
  • the amount of carbon dioxide therein can be varied to some extent depending upon the amount of air supplied via line 24 to roaster 22 and the carbon content of the cell lining material undergoing treatment.
  • the amount of sodium carbonate added via line 21 to roaster 212 in admixture with the cell lining material by controlling the amount of sodium carbonate added via line 21 to roaster 212 in admixture with the cell lining material, the amount of alumina, derivable from the Cryolite in the cell lining material, rendered soluble can be regulated so as to control the resulting recovered cryolite product purity.
  • the ⁇ free energy change favors the formation of sodium fluoride rather than sodium aluminate in accordance with the following chemical equation:
  • alumina surlicient to provide a weight ratio of A1203:F of about 0.45 in the cryolite precipitator or in the solution from which the cryolite is precipitated, is desired. Therefore, the amount of soda or sodium carbonate in the process will generally be in excess of that needed for the fluoride only and the reaction in roaster 22 will proceed in accordance with the chemical equation: j
  • Na3AlF6-i-2Na2CO3- NaF-i-NaAlOZ-l- 2G02 An excess of alumina can easily be added when processing ordinary cell lining material by adding more sodium carbonate and this may be desirable if auxiliary sources of lluoride or fluorine-containing materials, ⁇ such as scrubber solutions vfro-zn hydrogen iiuoride'or aluminum iluoride plants or aluminum smelters, are available and employed for the recovery of fluoride values therefrom, or sodium ll-uoride obtained from lluosilicate is available.
  • auxiliary sources of lluoride or fluorine-containing materials ⁇ such as scrubber solutions vfro-zn hydrogen iiuoride'or aluminum iluoride plants or aluminum smelters, are available and employed for the recovery of fluoride values therefrom, or sodium ll-uoride obtained from lluosilicate is available.
  • the elect of the amount of added sodium carbonate during the roasting operation upon the solubility of fluoride-containing materials and alumina is graphically illustrated in laccompanying FIG. 2. Accordingly, as indicated in FIG. 2 the weight ratio of alumina to fluorine in the precipitator solution can be varied in accordance Awithtthe amount of sodium carbonate added in the solids admixture supplied. via line 21 to or kpresent within roaster 22.
  • Scrubber solids are obtainable during the electrolytic 'refininglof aluminum by collecting the material volatilized from the cell, particularly at the anode, by water scrubbing.
  • the scrubber solutions may be utilized in the process of this invention and are conveniently utilized therein by being supplied ⁇ from a suitable source, not shown, via lline 28 to iilter 29 for the removal of the solids therefrom.
  • the resulting iiltered solids are withdrawn lfrom iilter 29 via line 30 and supplied via line 30 into mixer 20 for adm-ixture with the crushed and nely ground cell lining material therein.
  • ⁇ Cell lining material and scrubber solids normally Vcontain about 12-30% by Weight carbon.
  • these materials are roasted in adrnixture with sodium carbonate in roaster 22 to convert the cryolite therein to water-soluble sodium aluminate and ⁇ sodium lluoride at an elevated temperature, such as at least above about 500 C., the carbon therein is burned.
  • roaster 22 helps .to lmaintain the elevated temperature within roaster 22 needed to efr'ect the sodium carbonate-cryolite reaction and to evaporate any spent liquor which may be supplied or recycled to roaster in the conventional aqueous caustic cryolite recovery process are destroyed by reaction with air, sodium carbonate and/or water within roaster 22. Water-soluble cyanides which sometimes present a problem in the ,conventional caustic cryolite recovery process are also destroyed within roaster 22.
  • the resulting formed cryolite tends .to precipitate, particularly when the leaching solution approaches saturation with respect to the sodium fluoride and/ or the temperature of the leaching solution falls below about 50 C. Accordingly, it is desirable to maintain fthe aqueous leaching solution within leaching circuit or leaching tank 32 relatively hot, e.g. above about 50 C. It has been found, however, that the addition of sodium hydroxide, which may be added to leaching tank 32 in the form of a concentrated (eg. 50% by wt.) aqueous solution via line 35 in an amount of about 2 grams per liter based on the leaching solution, ile.
  • sodium hydroxide which may be added to leaching tank 32 in the form of a concentrated (eg. 50% by wt.) aqueous solution via line 35 in an amount of about 2 grams per liter based on the leaching solution, ile.
  • the 'leached solids are supplied via -line 36 to washing circuit or Washing tank 38 wherein the leached solids are washed with fresh wash water supplied to washing tank 38 from a suitable source, not shown, via line 39.
  • the resulting wash Water or overow from washing tank 38 is supplied via line 34 to leaching tank 32 to dissolve the water-soluble uor-ides and sodi-urn aluminate from the roaster product solids supplied thereto via line 26.
  • the tailings recovered trom washing tank 38 via line V40 contain up to '80%'V by 'weight alumina and if a red mud lime-soda sinter plant is operated nearby the alumina in these tailings can readily be utilized to commercial advantage.
  • the leaching circuit 32l and/or the washing circuit ⁇ 38 may comprise ⁇ a number of thickeners, filters or centrifuges orequivalent solids-liquids concentrating and/or separating devices. Concurrent or countercurrent operation of the leaching and/or Washing circuit may be employe'd but the countercurrent operation for both leaching and washingis preferred in the practice of this invention toreduce dilution. Further, it is preferred to leach and wash at temperatures close to the boiling point of the leaching and
  • the resulting solution or overflow from leaching circuit 32 is withdrawn therefrom via line 41 and supplied to surge tank 42 which is also, if desired, supplied with the filtrate of the scrubber slurries obtained from filter 29 via line 44.
  • surge tank 42 Because of the uctuations in the uoride and sodium carbonate contents of the cell lining material being processed the retention time of the liquids Within surge tank 42 should be about three times the roaster retention time with good mixing. Desirably, the liquid within surge tank 42 is sampled and analyzed frequently. -If the alumina to iluorine weight ratio therein is too low the sodium carbonate content in the feed supplied to roaster 22 via line 21, or present within roaster 22, should be increased. If the ratio is too high the sodium carbonate should be decreased. This control is desirable so that a reasonably high grade f recovered cryolite will be produced at all times.
  • the liquid in surge tank 42 is supplied via line 45 to rst stage cryolite precipitation or precipitator 46 wherein the liquid is contacted with the gaseous carbon dioxide in the roaster olf gases recovered from roaster 22 via line 25 after having passed through evaporator 48 and then to first stage precipitator 46 via lines 49 and 50.
  • rst stage cryolite precipitation or precipitator 46 wherein the liquid is contacted with the gaseous carbon dioxide in the roaster olf gases recovered from roaster 22 via line 25 after having passed through evaporator 48 and then to first stage precipitator 46 via lines 49 and 50.
  • cryolite is formed by reaction between carbon dioxide and sodium fluoride and sodium aluminate in accordance with the following chemical equation:
  • the material from first stage precipitator 46 is then supplied via line 51 to thickener 52 wherein a portion of the aqueous sodium carbonate-containing solution or spent liquor recovered via line 54 is supplied, if desired, via line 55 to leaching circuit 32. ln actual practice the spent liquor thus recycled via line 55 to leaching circuit 32 contains about 3 grams per liter fluorine.
  • the reason for the recycle of the partially spent liquor in line 55 to leaching circuit 32 is to reduce the water intake in the overall process and to reduce the evaporator requirements. This recycle also serves to raise the sodium carbonate content in the spent liquor returned to the roaster such as via line 31 from evaporator 48.
  • the cryolite-containing slurry is removed from thickener 52 via line 56 and passed to filter 5S for the separation of the cryolite therefrom.
  • the resulting separated cryolite is then passed via line 59y to dryer 60 and the resulting dried product recovered therefrom via line 61.
  • Second stage cryolite precipitation or second stage precipitator 65 is employed to elect substantially complete recovery of all the available cryolite from the raw material supplied to the process.
  • the slurry from second stage precipitator 65 is passed via line ⁇ 66 to thickener 68 for the removal of solids therefrom which are returned via line 69 to first stage precipitator 46.
  • the resulting spent liquor is recovered from thickener 68 via line 70 and is advantageously recycled to the process as the spent liquor supplied to ball mill 14 via line 15 or as the liquid employed as the scrubbing liquid in the production of scrubber slurries supplied to filter 29 via line 28 or the spent liquor may be supplied directly via line 71 to evaporator 48 for concentration of sodium carbonate therein and the production of the sodium carbonate slurry supplied via line 31 to mixer 20, or the spent liquor may be supplied directly, without concentration, to mixer 20 or to roaster 22 for temperature control therein, all as indicated in FIG. 1 of the drawings.
  • the cell lining material may contain as much as about 3% by weight sodium hydroxide and as much as about 10% by weight sodium carbonate.
  • sodium carbonate present in the cell lining material is inert.
  • both the sodium hydroxide and the sodium carbonate react substantially quantitatively with the cryolite to form water-soluble sodium fluoride and water-soluble sodium aluminate.
  • the sodium ion intake of the process of this invention is substantially less than that of the conventional caustic cryolite recovery process and therefore the spent liquor bleed is substantially less and uorine losses in the spent liquor are, accordingly, substantially reduced. Further, by evaporating part of the spent liquor all the sodium carbonate necessary for continuous operation of the subject process can be provided by the cell lining material itself, with sufficient surplus for scrubber operations if desired. Further, if another need for spent liquor presents itself it may even be more desirable or more economical to purchase dry soda ash (sodium carbonate) rather than to evaporate the spent liquor for the concentration and recovery of sodium carbonate therein.
  • a method of recovering cryolite values from cryolitecontaining carbonaceous cell lining material which comprises roasting an admixture consisting essentially of said carbonaceous cryolite-containing material with added soda carbonate, s-aidnoasting operation being carried out in the presence of a stoichiometric excess of sodium carbonate and at an elevated temperature and for a period of time sufficient to react ysubstantially all of the cryolite therein with sodium carbonate with the resulting formation of sodium flouride and sodium aluminate in accordance with the chemical equation y f Na3AlF6+2Na2CO3e GNaF-l-NaArlOg-l-ZCOz together with the formation of ⁇ sodium carbonate, separately recovering the precipitated cryolite and employing the sodium carbonate containedin the aforesaid aqueous solucion -to react with additional carbonaceous cryolitecontaining material for the recovery of cryolite therefrom.
  • a method of recovering cryolite from carbonaceous cryolite-containing cell lining material employed in the electrolytic refining of aluminum which comprises reducing said cryolite-containing cell lining material to panticle iorm, roasting an admixture consisting essentially of the resulting particle from' cell lining material in the presence of an added water-soluble carbonate selected from the group consisting :of sodium bicarbonate and sodium carbonate, said roasting operation being carried out in the presence of a stoichiometric excess of said water-soluble C.
  • a method of recovering cryolite values from carbonaceous, cryolite-containing cell lining material of an eleotrolytic cell employed in the -electrolytic refining of aluminum' which comprises, reducing said carbonaceous cryolite-containing cell lining material to particle form in the presence of aqueous spent liquor containing sodium carbonate dissolved therein; separating the resulting reduced cell lining material from said spent liquor, admixing added sodium carbonate with theV resulting reduced cell lining material to yield an admixture containing a stoichiometric excess of sodium carbonate, subjecting the resulting -admixture consisting essentially of reduced cell lining material and sodium carbonate to roasting at an elevated temperature in the range 500-900 C.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Geochemistry & Mineralogy (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
  • Electrolytic Production Of Metals (AREA)
US100268A 1961-04-03 1961-04-03 Recovery of cryolite Expired - Lifetime US3106448A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US100268A US3106448A (en) 1961-04-03 1961-04-03 Recovery of cryolite
SE3521/62A SE310658B (de) 1961-04-03 1962-03-29
DEA39851A DE1207362B (de) 1961-04-03 1962-03-30 Verfahren zur Rueckgewinnung von Kryolith aus kohlenstoffhaltigen Zellenauskleidungen
GB12548/62A GB981243A (en) 1961-04-03 1962-04-02 Recovery of cryolite
ES276075A ES276075A1 (es) 1961-04-03 1962-04-02 Un método de recuperar criolita del revestimiento interior de una celda electrolítica
CH399862A CH409417A (fr) 1961-04-03 1962-04-03 Procédé de récupération de la cryolite
FR893149A FR1324447A (fr) 1961-04-03 1962-04-03 Procédé de récupération de la cryolite

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US100268A US3106448A (en) 1961-04-03 1961-04-03 Recovery of cryolite

Publications (1)

Publication Number Publication Date
US3106448A true US3106448A (en) 1963-10-08

Family

ID=22278904

Family Applications (1)

Application Number Title Priority Date Filing Date
US100268A Expired - Lifetime US3106448A (en) 1961-04-03 1961-04-03 Recovery of cryolite

Country Status (6)

Country Link
US (1) US3106448A (de)
CH (1) CH409417A (de)
DE (1) DE1207362B (de)
ES (1) ES276075A1 (de)
GB (1) GB981243A (de)
SE (1) SE310658B (de)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3206280A (en) * 1960-07-04 1965-09-14 Electro Chimie Metal Process of recovering, in the form of cryolite, the fluorine from gases containing same
US3512927A (en) * 1965-07-26 1970-05-19 Anson G Betts Chemically treating phosphorite and obtaining separate products of fluorine and of phosphorus
US4113831A (en) * 1975-10-02 1978-09-12 National Fluoride And Chemical Corporation Recovery of sodium fluoride and other chemicals from spent carbon liners
EP0117616A1 (de) * 1983-01-25 1984-09-05 Alcan International Limited Herstellung von Aluminiumfluorid aus Auskleidungen von verbrauchten Aluminiumelektrolysezellen
US4597953A (en) * 1985-02-20 1986-07-01 Aluminum Company Of America Halogen recovery
US4889695A (en) * 1985-02-20 1989-12-26 Aluminum Company Of America Reclaiming spent potlining
US5164174A (en) * 1991-10-11 1992-11-17 Reynolds Metals Company Detoxification of aluminum spent potliner by thermal treatment, lime slurry quench and post-kiln treatment
US5776426A (en) * 1992-07-24 1998-07-07 Comalco Aluminium Limited Treatment of solid material containing fluoride and sodium including mixing with caustic liquor and lime
CN104499000A (zh) * 2014-12-12 2015-04-08 平顶山华兴浮选工程技术服务有限公司 一种电解铝碳渣的选矿处理方法
CN106086938A (zh) * 2016-06-30 2016-11-09 中南大学 一种超声波辅助加压碱浸回收铝电解废槽衬中电解质的方法
CN106077040A (zh) * 2016-06-30 2016-11-09 中南大学 一种超声波辅助碱浸处理铝电解废旧阴极炭块的方法
CN112624101A (zh) * 2020-12-23 2021-04-09 河南省冶金研究所有限责任公司 一种湿法处理电解铝废阴极材料的工艺
CN113426807A (zh) * 2021-06-29 2021-09-24 云南云铝润鑫铝业有限公司 铝电解危废渣联合处理和资源综合利用方法
CN115536050A (zh) * 2022-11-02 2022-12-30 中南大学 一种利用铝灰重组制备冰晶石的工艺方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113426808B (zh) * 2021-06-29 2022-05-17 云南云铝润鑫铝业有限公司 一种铝电解大修渣加压碱浸回收氟化盐的方法
CN114074949B (zh) * 2021-10-18 2023-06-27 郑州大学 一种电解槽废料中氟化物的催化解离方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1871723A (en) * 1929-05-29 1932-08-16 Aluminum Co Of America Process for the recovery of cryolite
US2196077A (en) * 1937-06-25 1940-04-02 Aluminum Co Of America Method of producing sodium aluminum fluoride
US2567544A (en) * 1945-01-26 1951-09-11 Alcan Aluminium Ltd Process for the manufacture of sodium aluminum fluoride
US2714053A (en) * 1952-11-26 1955-07-26 Vaw Ver Aluminium Werke Ag Process for the recovery of cryolite from the carbon bottoms of fusion electrolysis cells
US2732283A (en) * 1951-02-23 1956-01-24 O minutes

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE679849C (de) * 1936-11-17 1939-08-15 Ruetgerswerke Akt Ges Herstellung von Aluminium-Fluor-Verbindungen aus verbrauchtem Ofenfutter der Aluminium-Elektrolyse-Schmelzoefen
DE925407C (de) * 1952-10-26 1955-03-21 Vaw Ver Aluminium Werke Ag Verfahren zur Gewinnung von Kryolith aus Aluminium- und Fluorverbindungen enthaltenden Stoffen

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1871723A (en) * 1929-05-29 1932-08-16 Aluminum Co Of America Process for the recovery of cryolite
US2196077A (en) * 1937-06-25 1940-04-02 Aluminum Co Of America Method of producing sodium aluminum fluoride
US2567544A (en) * 1945-01-26 1951-09-11 Alcan Aluminium Ltd Process for the manufacture of sodium aluminum fluoride
US2732283A (en) * 1951-02-23 1956-01-24 O minutes
US2714053A (en) * 1952-11-26 1955-07-26 Vaw Ver Aluminium Werke Ag Process for the recovery of cryolite from the carbon bottoms of fusion electrolysis cells

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3206280A (en) * 1960-07-04 1965-09-14 Electro Chimie Metal Process of recovering, in the form of cryolite, the fluorine from gases containing same
US3512927A (en) * 1965-07-26 1970-05-19 Anson G Betts Chemically treating phosphorite and obtaining separate products of fluorine and of phosphorus
US4113831A (en) * 1975-10-02 1978-09-12 National Fluoride And Chemical Corporation Recovery of sodium fluoride and other chemicals from spent carbon liners
EP0117616A1 (de) * 1983-01-25 1984-09-05 Alcan International Limited Herstellung von Aluminiumfluorid aus Auskleidungen von verbrauchten Aluminiumelektrolysezellen
AU573560B2 (en) * 1983-01-25 1988-06-16 Alcan International Limited Fluoride-containing waste disposal
US4816122A (en) * 1983-01-25 1989-03-28 Alcan International Limited Preparation of aluminum fluoride from scrap aluminum cell potlinings
US4597953A (en) * 1985-02-20 1986-07-01 Aluminum Company Of America Halogen recovery
US4889695A (en) * 1985-02-20 1989-12-26 Aluminum Company Of America Reclaiming spent potlining
US5164174A (en) * 1991-10-11 1992-11-17 Reynolds Metals Company Detoxification of aluminum spent potliner by thermal treatment, lime slurry quench and post-kiln treatment
US5776426A (en) * 1992-07-24 1998-07-07 Comalco Aluminium Limited Treatment of solid material containing fluoride and sodium including mixing with caustic liquor and lime
CN104499000A (zh) * 2014-12-12 2015-04-08 平顶山华兴浮选工程技术服务有限公司 一种电解铝碳渣的选矿处理方法
CN106086938A (zh) * 2016-06-30 2016-11-09 中南大学 一种超声波辅助加压碱浸回收铝电解废槽衬中电解质的方法
CN106077040A (zh) * 2016-06-30 2016-11-09 中南大学 一种超声波辅助碱浸处理铝电解废旧阴极炭块的方法
CN106086938B (zh) * 2016-06-30 2019-01-04 中南大学 一种超声波辅助加压碱浸回收铝电解废槽衬中电解质的方法
CN112624101A (zh) * 2020-12-23 2021-04-09 河南省冶金研究所有限责任公司 一种湿法处理电解铝废阴极材料的工艺
CN113426807A (zh) * 2021-06-29 2021-09-24 云南云铝润鑫铝业有限公司 铝电解危废渣联合处理和资源综合利用方法
CN113426807B (zh) * 2021-06-29 2022-05-17 云南云铝润鑫铝业有限公司 铝电解危废渣联合处理和资源综合利用方法
CN115536050A (zh) * 2022-11-02 2022-12-30 中南大学 一种利用铝灰重组制备冰晶石的工艺方法

Also Published As

Publication number Publication date
GB981243A (en) 1965-01-20
ES276075A1 (es) 1962-07-16
SE310658B (de) 1969-05-12
CH409417A (fr) 1966-03-15
DE1207362B (de) 1965-12-23

Similar Documents

Publication Publication Date Title
US3106448A (en) Recovery of cryolite
US4465659A (en) Aluminum production via the chlorination of partially calcined aluminum chloride hexahydrate
GB843607A (en) Process for the separation of iron, aluminium and titanium values from materials containing them
US4465566A (en) Method of producing anhydrous aluminum chloride from acid leach-derived ACH and the production of aluminum therefrom
NO791478L (no) Fremgangsmaate ved separering av rutil
US2714053A (en) Process for the recovery of cryolite from the carbon bottoms of fusion electrolysis cells
US2654653A (en) Method of producing concentrates of uranium and vanadium from lowbearing ores
US3383166A (en) Process for producing iron-free aluminum nitrate solutions
US3047477A (en) Reduction of titanium dioxide
WO1989008723A1 (en) Recovery of lithium from a lithium bearing silicate ore
US1963105A (en) Method for the production of cuprous oxide
US1528319A (en) Process for the preparation of oxygenated compounds of titanium and pigments containing said compounds
US2204454A (en) Process for decomposing zirconium ore
US3900552A (en) Preparation of highly pure titanium tetrachloride from perovskite or titanite
US3808322A (en) Process for the recovery of sodium fluoride from waste fluoridic material and preparation of na3 fef6
US2059750A (en) Process for the production of lithium salts and metallic lithium
US3012878A (en) Titanium metal production process
US3853543A (en) Process for producing elemental copper by reacting molten cuprous chloride with zinc
US2752300A (en) Beneficiating titanium oxide ores
US3006723A (en) Process for the separation of aluminum from silicon in aluminum silicate ores
US2647829A (en) Decomposition of copper scrap and alloys with copper ammonium carbonate solutions
US2877110A (en) Recovery of manganese from metallurgical slags, dusts and ores
US2425995A (en) Process for treating oxidized ores of zinc
US2844499A (en) Method of removing oxygen from titanium metal
US2972517A (en) Method of producing lithium sulphate from alpha and beta spodumene