US2945791A - Inert lead dioxide anode and process of production - Google Patents

Inert lead dioxide anode and process of production Download PDF

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Publication number
US2945791A
US2945791A US719224A US71922458A US2945791A US 2945791 A US2945791 A US 2945791A US 719224 A US719224 A US 719224A US 71922458 A US71922458 A US 71922458A US 2945791 A US2945791 A US 2945791A
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anode
graphite
lead dioxide
solution
lead
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US719224A
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Jr Fred D Gibson
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Priority to US719224A priority Critical patent/US2945791A/en
Priority to GB7299/59A priority patent/GB893823A/en
Priority to DEG26543A priority patent/DE1182211B/de
Priority to SE205859A priority patent/SE200017C1/sv
Priority to BE576350A priority patent/BE576350A/fr
Priority to CH7037059A priority patent/CH395945A/de
Priority to FR788513A priority patent/FR1258830A/fr
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D9/00—Electrolytic coating other than with metals
    • C25D9/04—Electrolytic coating other than with metals with inorganic materials
    • C25D9/06—Electrolytic coating other than with metals with inorganic materials by anodic processes
    • 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
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/042—Electrodes formed of a single material
    • C25B11/043—Carbon, e.g. diamond or graphene
    • 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
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • 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
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/042—Electrodes formed of a single material
    • C25B11/043—Carbon, e.g. diamond or graphene
    • C25B11/044—Impregnation of carbon
    • 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
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/054—Electrodes comprising electrocatalysts supported on a carrier

Definitions

  • My invention relates to the electrodeposition of lead dioxide (PbO and more particularly to the electrosolutions containing lead salts, but invariably these deposits were not suited for electrochemical use as an inert or insoluble anode because they suifered from one or more of the following defects: (a) the lead dioxide deposit was non-uniform and non-adherent to the electrode surface; (b) the lead dioxide coating was too porous and too coarse; (c) the lead dioxide deposit would not withstand the normal abuse associated with the routine handling in thecommercial plant; and (d) the active :life of the electrode was drastically shortened due to excessive anode plate corrosion particularly above the solution level at the electrical bus connection.
  • PbO lead dioxide
  • the electrosolutions containing lead salts but invariably these deposits were not suited for electrochemical use as an inert or insoluble anode because they suifered from one or more of the following defects: (a) the lead dioxide deposit was non-uniform and non-adherent to the electrode surface; (b) the lead
  • Another object of my invention is to provide an inert and insoluble anode which can .be succmsfully used in the electrolytic production of chlorine, chlorates and per- -chlorates.from aqueous solutions without deterioration of the anode. or contamination of these electrochemical products.
  • the lead nitrate aqueous electrolyte Before starting, it is advantageous to have present in the lead nitrate aqueous electrolyte about 4 grams per liter of free nitric acid, as this improves the throwing power or coverage of the anode. electrolyte.
  • the graphite electrode should be soaked in water for about 24 hours before immersion in the electrolyte.
  • a graphite electrode is normally quite porous and these pores are filled with air.
  • any contained air and gas is displaced by the water, thus inhibiting the formation of pinholes in the lead dioxide coating.
  • a lead dioxide deposit is produced having the characteristics of a fine crystalline, randomly oriented structure, hard smooth surface, high tensile strength, and strong adherence to the graphite or carbon base substrate.
  • the lead dioxide coated graphite anode can be used directly in the electrolytic production of chlorine, chlorates or perchlorates without any further treatment.
  • the lead nitrate bath may be prepared as follows: Anhydrous lead nitrate is dissolved in Water to produce a liter of an aqueous solution having a concentration of 200 grams of lead nitrate per liter of solution.
  • the aqueous solution also contains the following compounds in the following concentrations: 10 grams per liter of cupric nitrate; 10 grams per liter of nickelous nitrate; 0.75 gram per liter of a surface active agent of the alkyl phenoxy polyoxy- .ethelene ethanol class; 0.50 gram per liter of sodium fluo- 5 ride; 4 grams per liter of nitric acid.
  • This bath will produce the desired dense type of PbO In addition, it dissolves sodium fluoride in the coated graphite electrode.
  • the cathode may be made of a suitable metal such as copper, stainless steel, nickel, platinum or the like. It is advisable to deposit the PbO in one operation without current interruption. In addition, it has been found that moderate agitation of the electrolyte aids in the production of complete coverage of the anode and reduces the nodulation. Nodular deposits are undesirable and my process produces few, if any, nodular deposits.
  • the PbO deposit will be found to be compact, hard, dense, smooth, tenacious, adherent to the electrode, and the crystals will be randomly oriented.
  • Satisfactory coatings have been used having thickness from about a thirty-second of an inch to about one-half an inch. I prefer a coating thickness of about a sixteenth to threesixteenths of an inch.
  • the function of the surface active agent is to raise the oxygen overvoltage at the anode, inhibit gassing and improve the throwing power of the nitrate bath, resulting thereby in a compact lead dioxide deposit.
  • the lead dioxide deposit tends to be spongy and porous. It functions in the same manner as natural hydrophilic colloids such as gelatine, dextrine, gum arabic, soluble starch, etc.
  • the surface active agent in the electrolyte is altered as the result of electrolysis in the presence of nitric acid.
  • These altered products interfere with electrodeposition resulting in time in a porous, non-adherent, non-uniform lead dioxide plate and ultimately the total lack of deposition.
  • a part of this difficulty can be overcome by allowing the neutralized cell effluent to stand neutral for more than 24 hours before reuse. This allows a portion of the altered products to recombine in the original form of the surface active agent.
  • this treatment is not completely eifective and over a period of time certain of the permanently altered products build up in concentration to a point where the solution is not usable and must be thrown away.
  • the solution can be regenerated as it leaves the cell as effluent by treating it with a small amount of n-amyl alcohol, i.e., about one liter of alcohol for four liters of solution and adding sufficient lead oxide to neutralize the contained nitric acid.
  • n-amyl alcohol i.e., about one liter of alcohol for four liters of solution and adding sufficient lead oxide to neutralize the contained nitric acid.
  • the alcohol removes substantially all of the residual surface active agent and its altered products and permits unlimited reuse of the solution.
  • the surface active agent and its altered products being immiscible with the solution, stratify out and can be removed by decantation.
  • a fresh amount, as above specified, of the surface active agent is added to the solution.
  • the solubility of the amyl alcohol in the nitrate bath is about 1% by weight.
  • Fig. 2 is a diagrammatic elevation of a plant arrangement
  • Fig. 3 is a vertical section of a cell for depositing lead dioxide
  • Fig. 4 is a diagrammatic top plan view of a cell of the type showing in Fig. 3;
  • Fig. 5 is a diagrammatic vertical section at right angles to Fig. 3, showing the cathode in fragmentary form.
  • 1 is the graphite anode and 2 are the cathodes.
  • Reference numeral 8 indicates the level of the electrolyte 7 in the cell tank 4.
  • Suitable electrical connections 9 and 10 lead to a power source for the supply current to the anode 1 and cathodes 2, respectively.
  • a feed solution tank 12 For feeding nitrate solution to the cell tank 4 there is a feed solution tank 12 with a valved pipe 13 discharging solution into the cell tank 4.
  • a siphon 15 For discharging solution from the cell tank 4 to a neutralizing tank 14, there is a siphon 15 which discharges into a pipe 16 and then into the tank 14.
  • An agitator 17 is operated by the motor 18.
  • the amyl alcohol 19 separates out and is decanted through the siphon 20 to a still for reuse and for removal to waste of the surface active agent residue.
  • the underflow from tank 14 is returned to the system through a pipe 21 to a filter 23 by a force pump 22.
  • the filtered neutral solution is returned to the feed tank 12 for delivery to the cell tank 4.
  • FIGs. 3 and 5 there is shown one form of cathode in which annealed copper wire 2a is wound across a plexiglass supporting plate 2b.
  • Other forms of well known similar cathodes may be used and are readily available.
  • Apertures 2c in the plate 2b and 1a in the graphite anode receive rods for supporting the anode and cathode in proper position in the cell tank 4.
  • the angular edges of the graphite anode are rounded at 1b and the bottom end 1c is cut in a half circular shape.
  • Feed solution was started at the same instant electrodeposition was initiated and was continuous thereafter at a rate sufiicient to maintain an acid concentration of approximately 4 grams per liter and a lead nitrate concentration of approximately grams per liter.
  • the feed solution was neutralized efiiuent from a previous run, free of surface active agent and containing approximately 1.15% by weight of n-amyl alcohol.
  • sodium fluoride and surface active agent were added at the rate of .5 gram and .75 gram respectively per liter of feed solution.
  • Effluent from the cell was neutralized with lead oxide and thoroughly mixed with n-amyl alcohol. On settling, the alcohol containing substantially all of the surface active agent and altered products separated from the nitrate solution. This alcohol layer was decanted and then distilled to recover the alcohol. The cleaned neutral solutions containing approximately 1% by weight of alcohol was filtered and returned to the electrolytic cell as feed solution and the above cycle repeated.
  • V p g g Cathode Two sections each containing 064 dia; soft aiinealedc'opper wire wound across 7.5" x 24" Plexiglas plates so as to give an immersed area of approximately 142 sq. in.
  • EXAMPLE II I proceeded as in Example I, above, except that neither the electrolyte nor the feed solution contained n-amyl alcohol.
  • the anode was a 3" diameter by 14" long rod of'untreated graphite with the lower end rounded in a' spherical shape.
  • Cathode 273 x .064 dia. soft annealed copper wire strung vertrcally between two 7 dia. Plexiglas plates (bird cage efiect) to give an effective area of approximately 55 sq. in.
  • EXAMPLE III The lead dioxide coatedgraphite anodeprepared as above, was used as-an *an'ode in the electrolysis of an aqueous sodium chloratesolution to produce a sodium perchlorate solution. Subsequent to the electrodeposition of the lead dioxide and before use in this operation no further treatments of any kind were made to the anode. The same electrical connection to the uplated top portion of the graphite base was utilized in both the electrodeposition of the lead dioxide and the electrolysis of the sodium chlorate solution.
  • a nearly-saturated aqueous solution of sodium chlorate was prepared from technical grade sodium chlorate.
  • the solution was purified of chromate by precipitation with barium chloride and filtered. Approximately .5 g.p.l. of NaF was added to inhibit cathode reduction.
  • the electrolysis was carried out in a 12 dia. x 24" high Pyrex jar in which the anode and two type 316 stainless steel cathodes were immersed.
  • the electrolyte was cooled by water flowing thru glass coils placed within the cell.
  • the electrolyte was agitated by means of magnetic stirrer.
  • hydrochloric acid was added in order to maintain a pH of 5.0 to 6.8. No further acid additions were required.
  • the electrolysis was stable and continuous and continued until theelectrolyte was nearly free of chlorate.
  • the lead dioxide coated graphite was untouched and unattacked and no contaminants were transferred to the sodium perchlorate therefrom.
  • the cumulative current efiiciency of 75.5% was greater than the 60 to usually encounterediin commercial sized platinum anode perchlorate cells.
  • the average voltage of 4.75 was also considerably lower than the usual 6.5 to 6.9 recorded in platinum anode perchlorate cells.
  • Efiective area approximately 166 square inches each. Spacing: 1/2 inch between cathode surface and anode surface Cell: 12" dia. 24 high Pyrex jar Voltage: 4.75 Applied current: 285 amperes Current density:
  • EXAMPLE V The anode prepared as above was used as an anode in the electrochemical production of chlorine from a sodium chloride solution.
  • a saturated solution of sodium chloride was used as an electrolyte.
  • the anode and cathode compartments were separated by an asbestos diaphragm and each compartment was sealed from the air by Plexiglas covers.
  • Chlorine formed at the anode was drawn ofi and absorbed in caustic soda. Hydrogen and caustic were formed at the cathode.
  • the caustic soda was continuously removed as a 14% solution. This effiuent from the cathode chamber was replaced by an equivalent volume of salt solution which percolated thru the diaphragm from the anode chamber.
  • This salt solution was in turn replaced by fresh feed to the anode chamber.
  • a temperature of approximately 95 C. was maintained in the cell by means of two quartz type im- Periodic inspection of the lead dioxide anode showed both the plate and the graphite to be unattacked and unchanged.
  • Electrolyte Saturated sodium chloride solution Anode: Same as in Example IV Cathode: 2 sections A thick 6" x 24" iron sheets immersed 20". Effective area 120 sq. inches each.
  • theelectrolyte consisting essentially of an aqueous acid solution of lead nitrate in a conceneration, and at a temperature that will deposit lead. dioxide on the graphite anode.
  • the improvement comprising varying the anode current density for at least two successive periods of electro-deposition, the anode current density varying from about to 150 amperes per square foot for the prior period of electro-deposition to about 20 to 60 amperes per square foot for the succeeding period of electrodeposition, to completely cover the graphite anode with a compact, hard, dense, smooth coating having randomly oriented crystals firmly bound to the graphite base.
  • An anode for use with corrosive electrolytes having a graphite base, and having electrolytically deposited thereon a massive coating of lead dioxide completely covering the immersible active portion of the anode, the coating being smooth, compact, hard, firmly bound to the base, with randomly oriented crystals and produced by the process of claim 1.

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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)
  • Inorganic Chemistry (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
US719224A 1958-03-05 1958-03-05 Inert lead dioxide anode and process of production Expired - Lifetime US2945791A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US719224A US2945791A (en) 1958-03-05 1958-03-05 Inert lead dioxide anode and process of production
GB7299/59A GB893823A (en) 1958-03-05 1959-03-03 Inert lead dioxide anode and process of production
DEG26543A DE1182211B (de) 1958-03-05 1959-03-04 Verfahren zur elektrolytischen Abscheidung eines Bleidioxydueberzugs auf einer Graphitanode
SE205859A SE200017C1 (de) 1958-03-05 1959-03-04
BE576350A BE576350A (fr) 1958-03-05 1959-03-04 Anode en dioxyde de plomb inerte et procédé pour sa fabrication.
CH7037059A CH395945A (de) 1958-03-05 1959-03-04 Verfahren zur Herstellung einer inerten Bleidioxydelektrode, nach diesem Verfahren hergestellte Bleidioxydelektrode und Verwendung derselben
FR788513A FR1258830A (fr) 1958-03-05 1959-03-05 Procédé de formation d'un dépôt de bioxyde de plomb pour revêtement d'anode inerte et anode formée par ce procédé

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US719224A US2945791A (en) 1958-03-05 1958-03-05 Inert lead dioxide anode and process of production

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BE (1) BE576350A (de)
CH (1) CH395945A (de)
DE (1) DE1182211B (de)
GB (1) GB893823A (de)
SE (1) SE200017C1 (de)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3102085A (en) * 1958-06-27 1963-08-27 Ici Ltd Treatment of brine solutions
US3207679A (en) * 1960-05-03 1965-09-21 American Potash & Chem Corp Method for electroplating on titanium
US3213004A (en) * 1961-03-08 1965-10-19 American Potash & Chem Corp Surface preparation of platinum group metals for electrodeposition
US3392094A (en) * 1963-08-08 1968-07-09 Cominco Ltd Process for preconditioning lead or lead-alloy electrodes
US3410771A (en) * 1965-05-03 1968-11-12 Wallace & Tiernan Inc Treatment of lead alloy anodes
US3440149A (en) * 1962-05-22 1969-04-22 Ionics Stable lead anodes
US3463707A (en) * 1965-06-16 1969-08-26 Pacific Eng & Production Co Electrodeposition of lead dioxide
US3909369A (en) * 1974-05-23 1975-09-30 Council Scient Ind Res Method for the production of an electrode for cathodic protection
US3935082A (en) * 1973-02-13 1976-01-27 Rheinisch-Westfalisches Elektrizitatswerk Ag Process for making lead electrode
US4038170A (en) * 1976-03-01 1977-07-26 Rhees Raymond C Anode containing lead dioxide deposit and process of production
US4203812A (en) * 1977-03-25 1980-05-20 Hoechst Aktiengesellschaft Process for preparing basic aluminum chlorides
US4236978A (en) * 1980-02-08 1980-12-02 Rsr Corporation Stable lead dioxide anode and method for production
US20210221710A1 (en) * 2018-06-29 2021-07-22 Centre National De La Recherche Scientifique Method for decontaminating heavy metals in an aqueous solution

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4130467A (en) * 1977-03-07 1978-12-19 British Columbia Research Council Process for plating lead dioxide
US5830340A (en) * 1997-03-05 1998-11-03 Trumem International Llc Method for making a composite filter

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB456082A (en) * 1934-12-20 1936-11-03 Yogoro Kato Improvements in or relating to the electrolytic deposition of lead peroxide
US2846378A (en) * 1956-02-07 1958-08-05 American Potash & Chem Corp Electrode and its manufacture
US2872405A (en) * 1955-12-14 1959-02-03 Pennsalt Chemicals Corp Lead dioxide electrode

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE195117C (de) *
DE206329C (de) * 1905-11-09 1909-02-04 Paul Ferchland Bleisuperoxydanode für elektrolytische Zwecke

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB456082A (en) * 1934-12-20 1936-11-03 Yogoro Kato Improvements in or relating to the electrolytic deposition of lead peroxide
US2872405A (en) * 1955-12-14 1959-02-03 Pennsalt Chemicals Corp Lead dioxide electrode
US2846378A (en) * 1956-02-07 1958-08-05 American Potash & Chem Corp Electrode and its manufacture

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3102085A (en) * 1958-06-27 1963-08-27 Ici Ltd Treatment of brine solutions
US3207679A (en) * 1960-05-03 1965-09-21 American Potash & Chem Corp Method for electroplating on titanium
US3213004A (en) * 1961-03-08 1965-10-19 American Potash & Chem Corp Surface preparation of platinum group metals for electrodeposition
US3440149A (en) * 1962-05-22 1969-04-22 Ionics Stable lead anodes
US3392094A (en) * 1963-08-08 1968-07-09 Cominco Ltd Process for preconditioning lead or lead-alloy electrodes
US3410771A (en) * 1965-05-03 1968-11-12 Wallace & Tiernan Inc Treatment of lead alloy anodes
US3463707A (en) * 1965-06-16 1969-08-26 Pacific Eng & Production Co Electrodeposition of lead dioxide
US3935082A (en) * 1973-02-13 1976-01-27 Rheinisch-Westfalisches Elektrizitatswerk Ag Process for making lead electrode
US3909369A (en) * 1974-05-23 1975-09-30 Council Scient Ind Res Method for the production of an electrode for cathodic protection
US4038170A (en) * 1976-03-01 1977-07-26 Rhees Raymond C Anode containing lead dioxide deposit and process of production
US4203812A (en) * 1977-03-25 1980-05-20 Hoechst Aktiengesellschaft Process for preparing basic aluminum chlorides
US4236978A (en) * 1980-02-08 1980-12-02 Rsr Corporation Stable lead dioxide anode and method for production
US20210221710A1 (en) * 2018-06-29 2021-07-22 Centre National De La Recherche Scientifique Method for decontaminating heavy metals in an aqueous solution

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CH395945A (de) 1965-07-31
BE576350A (fr) 1959-07-01
SE200017C1 (de) 1965-11-30
GB893823A (en) 1962-04-11
DE1182211B (de) 1964-11-26

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