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US3773644A - Electrolytic cell for the production of fluorine - Google Patents

Electrolytic cell for the production of fluorine Download PDF

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Publication number
US3773644A
US3773644A US00148831A US3773644DA US3773644A US 3773644 A US3773644 A US 3773644A US 00148831 A US00148831 A US 00148831A US 3773644D A US3773644D A US 3773644DA US 3773644 A US3773644 A US 3773644A
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United States
Prior art keywords
cell
anode
anodes
fluorine
cathode
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Expired - Lifetime
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US00148831A
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English (en)
Inventor
A Tricoli
A Battarra
G Rebua
L Bestetti
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Montedison SpA
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Montedison SpA
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Publication date
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
    • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms

Definitions

  • the anodes are supported by the cell cover through a stuffing box arrangement and are substantially round in cross-section.
  • a cathode associated with each anode coaxially with respect thereto consists of a substantially cylindrical pipe, with provision for a diaphragm consisting of a substantially cylindrical pipe, coaxial with the anode, and disposed between the anode and the cathode.
  • the present invention relates to an improved electrolytic cell for the production of fluorine.
  • Tee process of the electrolytic production of fluorine by using a fused mixture of potassium fluoride and hydrofluoric acid as electrolyte is already well known.
  • electrolytic cells comprising a certain number of cathodes and anodes immersed in the electrolyte and a diaphragm separating the cathodic zone from the anodic zone for preventing the developed gaseous hydrogen and fluorine from mixing with each other.
  • the amorphous carbon anodes of these known cells are partially immersed in the electrolyte and are supported by a metal beam placed inside the cell.
  • the anodes are tightly fastened to said beam by means of bolts in order to bring about good metal-to-carbon electrical contact for the current to the cell.
  • An object of the present invention is to provide an improved cell which will eliminate or reduce to a minimum these and other drawbacks.
  • an object of this invention is the elimination of the anodes-carrying beam and the accompanying electrical connection inside the cell.
  • a further object of this invention is to provide a low resistance electrical connection of constant efficiency through the entire cell operation time or cycles, an electrical efficiency which, in comparison with the efficiency herebefore obtainable from a conventional anodic unit, is far superior and which suffers no deterioration in the long run.
  • a still further object is a construction and arrangement making it possible to detect, on an assembled and operating cell, the particular anode or anodes which may have broken and therefore require replacement, as well as making it possible to replace an accidentally broken anode without being forced to remove the cell cover, thus requiring a stoppage of the cell which is far shorter than the stoppage heretofore required by a conventional-type cell.
  • a still further object of this invention is a construction and arrangement that will bring about a decrease compared with conventional cells in the amount of the corrosionproducts (forming during the cell operation and ending by mixing with the electrolyte thus requiring a periodical replacement of the said electrolyte) and the elimination of the CF, from the fluorine and consequently also from the products obtained via fluorination with fluorine.
  • an improved electrolytic cell for the production of fluorine which, according to this invention, is provided with carbon anodes protruding from the cell, each anode having its section protruding from the cell covered by a gasproof coat made of a good electrically-conducting material, through which and by which the electrical connection for the current to the cell is assured.
  • the electrolytic cell for the production of fluorine comprises: tank 1, made of Monel-alloy sheet metal for containing the electrolyte and surrounded by jacket 2 or other means suitable for heating or cooling the contents of the tank;
  • anodes4 made of amorphous carbon, cylindrically shaped and vertically positioned, partially dipping in electrolyte 11, each of the anodes protruding from the cover of the cell, their section protruding from the cover being provided with coat 5, made of suitable metal (copper, for example), and the current input connection being placed outside the cell and completed through suitably shaped copper clamps 6, said anodes being mechanically supported by the cell cover but being electrically insulated therefrom by means of stuffing box 7' made of an insulating material (e.g., polytetrafluoroethylene). which provides a gastight connection preventing the escape of the gases (fluorine and hydrogen fluoride) that develop inside the cell;
  • an insulating material e.g., polytetrafluoroethylene
  • an electrolyte-immersed cathode consisting of as many steel pipes 8 as there are anodes, each arranged concentrically with respect to an anode and welded together in such a way as to constitute a whole unit whereby the electric current is led through two or more round steel bars (not shown in the drawing for simplicity and which also support the cathode inside the cell) passing through the cell cover 3 from which they are electrically insulated by means of a gastight stuffing box which prevents escape of the gases (hydrogen and hydrogen fluoride) developing within the cell;
  • diaphragms equal in number to the number of the anodes, their upper part consisting of pipes 9 made of Monel-alloy metal and welded at their top end to the cell cover 3 and extending downwardly into the electrolyte 11 so to provide a gasproof barrier, their lower part consisting of a Monel-alloy metal plate (which may or may not be perforated) completely immersed in the electrolyte, the diaphragm having a cylindrical pipe shape and a diameter corresponding to that of the Monel-alloy pipe section.
  • the diaphragms 9 and 10 are located concentrically with respect to the amorphous carbon anodes, and are equally spaced with respect to the same anodes and the steel pipes 8 constituting the cathode.
  • Pipes (not shown in the drawing) are provided for the separate introduction of hydrofluoric acid into the cell.
  • a seal 12 is provided between tank 1 and cover 3 of the cell.
  • tubular diaphragms 10 have their lower end terminating in a grid-protected opening 13 to which bushing 14, preferably made of polytetrafluoroethylene, is attached for the main purpose of self-centering the anode 4 during the assembly stage, while having also the additional function of supporting it in proper position within the cell.
  • bushing 14 preferably made of polytetrafluoroethylene
  • the stuffing box unit 7 which, as indicated above, has the double task of supporting anode 4 while electrically insulating it from the cell cover 3 and of preventing the escape of fluorine and hydrogen fluoride from the cell, consists of sleeve 7 assembled in such a way as to slide along the anode axis and acting on elastic gasket 15 due to the force developed by bolts shown only by their axes 16 in the drawing.
  • the sleeve 7 and the gasket 15 are preferably made of polytetrafluoroethylene. The assembly and disassembly of the individual anodes is'made easy and quick by this stuffing box arrangement which assures perfect tightness against the escape of gases forming inside the cell.
  • each anode protruding from the cell is provided with a coat 5 made of an electrically conducting material (copper, for example) through which the electrical connection is achieved and the anode section protruding from the cell is made gasproof.
  • the coat 5 can'have various constructions and for example may consist of a copper cap coupled to the anode end by a force fit.
  • EXAMPLE 1 Use .was made of a cell according'to the present invention and comprising a tank made of Monel-alloy,
  • the anodes were independent of each other as regards the electrical connection placed outside the cell.
  • the anode section outside the cell was fully copper coated and was provided with a copper clamp through which the current input was assured.
  • the electrolyte was a mixture of hydrofluoric acid and potassium fluoride having a composition of about KF.1.8 HF.
  • the operating temperature was approximately 100C.
  • the cell was run with an anodic current skin density of about 0.1 A/cm
  • the recorded life of the anodes was more than months, corresponding for the particular cell to a total of 24.10 A/h.
  • EXAMPLE 2 Cover, cathode and diaphragm of the types commonly used in the conventional cells for fluorine production (for further information about the structure of this cell style, see the above-cited articles) were assembled to form a cell consisting of a Monel-alloy tank shaped and dimensioned the same as in the previous example.
  • the anodic unit consisted of 8 anode pairs of amorphous carbon having a rectangular section, and supported by an anode-carrying metal beam to which the anodes were tightly bolted.
  • the anodecarrying beam placed inside the cell was in its turn supported by three copper current-carrying bars which protruded from the cover through stuffing box devices.
  • the cell was operated at about 0.l A/cm anodic current skin density.
  • the Monel-alloy diaphragms were two in number and the cathode consisted of two steel pipes. They too had shape, dimensions and constructional details the same as specified in Example 1.
  • the electrolyte had a composition of approximately KF.1.8 HF.
  • the operating temperature was about 100C.
  • the cell was operated at an anodic current skin density of about 0.15 A/cm On this case, although the anodic current skin density was significantly higher, the life of the anodes still appeared to be longer than 12 months.
  • EXAMPLE 4 Cover, cathode, anode and diaphragm as commonly used for fluorine producing cells of conventional style were assembled to form an experimental cell consisting of a tank the same as described in Example 3.
  • the anodes were two in number made of amorphous carbon and rectangularly shaped. They were tightly bolted to an anode-carrying metal beam placed inside the cell.
  • the cell was run with an anodic current skin density of about 0.15 A/cm At this significantly higher anodic current skin density, the life of the anodes appeared to be less than or at the most equal to two months.
  • the occasional breaking of an anode can be immediately detected from outside the cell and the replacement of theindividual broken anode requires a quired the disassembly of the cell for replacement of v the anode unit.
  • the resistance between the carbon anodes and the metal beam had a value well above the value shown at the beginning of the run.
  • the resistance of the new anode unit was lower than 1,000 microhms per anode (the metering of this resistance having been carried out between the anode end and the metal beam), but at the end of each run it reached values ranging from 40,000 to 100,000 microhms through the broken anodes while values up to 10,000 microhms were recorded through the undamaged anodes.
  • EXAMPLE 3 Use was made of an experimental cell according to this invention.
  • the cell consisting of a Monel-alloy tank having a rectangular horizontal section, provided with a cooling jacket and a steel cover.
  • the anodes were two in a number made of amorphous carbon. Their shape and dimensions as well as time much shorter than the same operation requires for a conventional cell. Maintenance costs are consequently substantially reduced both because the work for replacing any individual broken anode is remarkably simplified and because in an event the breaking of the individual anodes occurs more rarely in the improved cell construction of the present invention.
  • the new electrical connection between the carbon anodes and the metal parts is located outside the cell, and consequently not adversely influenced by corrosion phenomena, the result is that said connection suffers no loss of efficiency in the long run and the electric efficiency thereof always remains at a desirably high value.
  • An improved electrolytic cell for the production of a cathode inside said tank made of a metal pipe coaxprevent mixing of the hydrogen and fluorine develially arranged with respect to said anode, the elecoped at said cathode and anode respectively. trical connection to said cathode being effected in- 2.
  • the electrolytic cell of claim 1 wherein said anode side the tank, and is supported by said cell cover through a stuffing box a diaphragm, inside said tank, made of a metal pipe 5 device.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
  • Electrolytic Production Of Metals (AREA)
US00148831A 1970-06-01 1971-06-01 Electrolytic cell for the production of fluorine Expired - Lifetime US3773644A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT2539070 1970-06-01

Publications (1)

Publication Number Publication Date
US3773644A true US3773644A (en) 1973-11-20

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US00148831A Expired - Lifetime US3773644A (en) 1970-06-01 1971-06-01 Electrolytic cell for the production of fluorine

Country Status (9)

Country Link
US (1) US3773644A (de)
JP (1) JPS5436152B1 (de)
BE (1) BE767921A (de)
CA (1) CA938249A (de)
DE (1) DE2126820C3 (de)
ES (1) ES391761A1 (de)
FR (1) FR2095766A5 (de)
GB (1) GB1354314A (de)
NL (1) NL170314C (de)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4504366A (en) * 1983-04-26 1985-03-12 Aluminum Company Of America Support member and electrolytic method
US4511440A (en) * 1983-12-22 1985-04-16 Allied Corporation Process for the electrolytic production of fluorine and novel cell therefor
US4609249A (en) * 1985-04-25 1986-09-02 Aluminum Company Of America Electrically conductive connection for an electrode
US4664760A (en) * 1983-04-26 1987-05-12 Aluminum Company Of America Electrolytic cell and method of electrolysis using supported electrodes
US5290413A (en) * 1991-07-26 1994-03-01 Minnesota Mining And Manufacturing Company Anodic electrode for electrochemical fluorine cell
US5688384A (en) * 1994-09-14 1997-11-18 British Nuclear Fuels Plc Fluorine cell
US6146506A (en) * 1993-09-03 2000-11-14 3M Innovative Properties Company Fluorine cell
US6210549B1 (en) * 1998-11-13 2001-04-03 Larry A. Tharp Fluorine gas generation system
US20030121796A1 (en) * 2001-11-26 2003-07-03 Siegele Stephen H Generation and distribution of molecular fluorine within a fabrication facility
WO2004005584A1 (en) * 2002-07-06 2004-01-15 The Boc Group Plc Fluorine cell
US20040149570A1 (en) * 2003-01-22 2004-08-05 Toyo Tanso Co., Ltd. Electrolytic apparatus for molten salt
US20050191225A1 (en) * 2004-01-16 2005-09-01 Hogle Richard A. Methods and apparatus for disposal of hydrogen from fluorine generation, and fluorine generators including same
US20090001524A1 (en) * 2001-11-26 2009-01-01 Siegele Stephen H Generation and distribution of a fluorine gas

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4664760A (en) * 1983-04-26 1987-05-12 Aluminum Company Of America Electrolytic cell and method of electrolysis using supported electrodes
US4504366A (en) * 1983-04-26 1985-03-12 Aluminum Company Of America Support member and electrolytic method
US4511440A (en) * 1983-12-22 1985-04-16 Allied Corporation Process for the electrolytic production of fluorine and novel cell therefor
US4609249A (en) * 1985-04-25 1986-09-02 Aluminum Company Of America Electrically conductive connection for an electrode
US6063255A (en) * 1991-07-26 2000-05-16 3M Innovative Properties Company Anodic electrode for electrochemical fluorine cell
US5290413A (en) * 1991-07-26 1994-03-01 Minnesota Mining And Manufacturing Company Anodic electrode for electrochemical fluorine cell
AU649141B2 (en) * 1991-07-26 1994-05-12 Minnesota Mining And Manufacturing Company Anodic electrode for electrochemical fluorine cell
US6146506A (en) * 1993-09-03 2000-11-14 3M Innovative Properties Company Fluorine cell
US5688384A (en) * 1994-09-14 1997-11-18 British Nuclear Fuels Plc Fluorine cell
US6210549B1 (en) * 1998-11-13 2001-04-03 Larry A. Tharp Fluorine gas generation system
US20030121796A1 (en) * 2001-11-26 2003-07-03 Siegele Stephen H Generation and distribution of molecular fluorine within a fabrication facility
US20090001524A1 (en) * 2001-11-26 2009-01-01 Siegele Stephen H Generation and distribution of a fluorine gas
WO2004005584A1 (en) * 2002-07-06 2004-01-15 The Boc Group Plc Fluorine cell
US20060113186A1 (en) * 2002-07-06 2006-06-01 Graham Hodgson Fluorine cell
CN100351432C (zh) * 2002-07-06 2007-11-28 波克股份有限公司 氟电解槽
US7481911B2 (en) 2002-07-06 2009-01-27 The Boc Group Plc Fluorine cell
US20040149570A1 (en) * 2003-01-22 2004-08-05 Toyo Tanso Co., Ltd. Electrolytic apparatus for molten salt
US20080128270A1 (en) * 2003-01-22 2008-06-05 Toyo Tanso Co., Ltd. Electrolytic apparatus for molten salt
US20050191225A1 (en) * 2004-01-16 2005-09-01 Hogle Richard A. Methods and apparatus for disposal of hydrogen from fluorine generation, and fluorine generators including same

Also Published As

Publication number Publication date
NL170314C (nl) 1982-10-18
BE767921A (fr) 1971-12-01
DE2126820C3 (de) 1980-12-11
NL7107373A (de) 1971-12-03
ES391761A1 (es) 1974-06-16
CA938249A (en) 1973-12-11
FR2095766A5 (de) 1972-02-11
DE2126820B2 (de) 1980-04-24
DE2126820A1 (de) 1971-12-16
NL170314B (nl) 1982-05-17
JPS5436152B1 (de) 1979-11-07
GB1354314A (en) 1974-06-05

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