EP0148439B1 - Aktivierte Metallanoden sowie ein Verfahren zu deren Herstellung - Google Patents

Aktivierte Metallanoden sowie ein Verfahren zu deren Herstellung Download PDF

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Publication number
EP0148439B1
EP0148439B1 EP84115214A EP84115214A EP0148439B1 EP 0148439 B1 EP0148439 B1 EP 0148439B1 EP 84115214 A EP84115214 A EP 84115214A EP 84115214 A EP84115214 A EP 84115214A EP 0148439 B1 EP0148439 B1 EP 0148439B1
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EP
European Patent Office
Prior art keywords
anode
manganese
titanium
metallic
weight
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
EP84115214A
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German (de)
English (en)
French (fr)
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EP0148439A2 (de
EP0148439A3 (en
Inventor
Eberhard Dr. Preisler
Heiner Dr. Debrodt
Dieter Lieberoth
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.)
Hoechst AG
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Hoechst AG
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Publication of EP0148439A3 publication Critical patent/EP0148439A3/de
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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
    • 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
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound

Definitions

  • the present invention relates to activated metal anodes, preferably those which are used in electrochemical processes in which the process product is deposited in solid form on the anode, and to a process for producing these anodes.
  • Electrolytically generated manganese dioxide is deposited technically on the anode of an electrolysis cell which contains a hot sulfuric acid manganese sulfate solution as the electrolyte. After the anode has been lifted out, the coating is knocked off by mechanical impacts and processed further.
  • lead and its alloys, graphite or titanium are known to be used as anode materials.
  • each of these materials has specific advantages and disadvantages, but in recent times titanium has become increasingly interesting because titanium anodes can be reused unchanged for a long time and because the titanium emits practically no contamination of the product, as is the case with lead alloys.
  • non-activated titanium can be used as an anode because a layer of manganese dioxide is deposited on it immediately after the formation of an extremely thin passive layer.
  • This manganese dioxide is a comparatively good electron conductor, so that electrons instead of oxygen ions enter the manganese dioxide-titanium dioxide phase boundary, which can pass freely through the thin passive layer without it continuing to grow (cf. Chem. Ing. Techn. 49, 347 (1977)) .
  • the passive layer of titanium continues to grow under a manganese dioxide layer only if certain limits of the electrolysis conditions are met.
  • Critical bath conditions are current density, sulfuric acid concentration, manganese concentration and the temperature.
  • a titanium anode is the least sensitive to changes in the manganese concentration of the electrolyte, particularly sensitive to lowering the temperature. Since the three critical operating parameters interact closely with one another, no absolute limit values can be set for each individual operating parameter. It can therefore only be checked by means of ongoing comparative tests within the framework of the technically interesting conditions whether a titanium anode behaves favorably or not.
  • a titanium anode was already described in SU-PS 891 805, which has a satisfactory stability during the electrolysis at room temperature.
  • This anode consists entirely of a titanium-manganese alloy with a manganese content between 6 and 16% by weight of manganese, on the surface of which a layer of ⁇ -manganese dioxide is applied by means of multiple thermal decomposition of manganese nitrate.
  • this electrode is unsuitable for the technical production of electrolytic manganese dioxide (EMD), because a ß-Mn0 2 layer applied in this way is not sufficiently stable against the mechanical stress when knocked off.
  • titanium alloys with a manganese content of more than 16% by weight are brittle and can no longer be machined or deformed mechanically. The rollability of titanium-manganese alloys is lost even at significantly lower manganese contents.
  • the object of the present invention is to provide an anode, in particular for the electrochemical production of manganese dioxide, which does not have the disadvantages listed above, which can therefore be used repeatedly without additional measures for electrolysis under conditions in which pure titanium is passivated, the anode base being mechanically machinable and deformable, so that the anode shape can be chosen as freely as in use from pure titanium.
  • this object can be achieved by means of a metal anode which consists of a metal from the group of the so-called valve metals zirconium, niobium, tantalum or preferably titanium and which is activated on its surface with metallic manganese, the manganese content on the anode surface is more than 16% by weight, preferably 20 to 60% by weight, and decreases towards the inside of the anode to such an extent that - measured from the anode surface - the manganese content within a range which is at most 1/4 of the material thickness the anode corresponds to - preferably within a range of 100 to 300 gm - decreased to 0% by weight.
  • Another object of the present invention is a method for producing these activated anodes, which consists in applying a layer of metallic manganese to the surface of an anode base consisting of the aforementioned valve metals zirconium, niobium, tantalum or preferably titanium and the anode then treated at a temperature between 800 and 1150 ° C, preferably between 950 and 1100 ° C, 4 hours to 1/2 hour in an inert atmosphere, for example a noble gas atmosphere, or in vacuo, the longer and choose the shorter treatment times at the higher temperatures.
  • the anode base should expediently consist of technically pure titanium and can be made from both solid titanium and sintered titanium.
  • the manganese is advantageously applied to the anode base by electrolytic means.
  • the anode base consists of sintered valve metal
  • the manganese is also possible to apply the manganese to the anode base in a plasma spraying process (sputtering).
  • the absolute manganese concentrations on the anode surface and the concentration gradients in the surface area can be varied within wide limits by the method according to the invention. This can be done both by the amount of manganese applied primarily to the anode base and by the conditions of the subsequent thermal treatment. These measures are to be coordinated with one another in such a way that the manganese concentration on the anode surface is more than 16% by weight, preferably 20 to 60% by weight.
  • the end terminal voltage of the cell was registered, the manganese dioxide coating was removed and the electrode was reinserted in the bath and electrolysis resumed. The initial terminal voltage was also registered.
  • An electrode consisting of a pure titanium sheet with an area of 0.4 dm 2 immersed in the bath was used as the anode under the conditions mentioned.
  • the initial terminal voltage was 2.3 V, reached 3.0 V after 4 days, 4.0 V after 8 days and more than 10 V on the 9th day.
  • Example 2 The same titanium sheet as in Example 1 was coated on both sides by cathodic deposition from a bath containing manganese and ammonium sulfate with 1.5 g / dm 2 of manganese metal and annealed for one hour at 950 ° under an argon protective gas atmosphere.
  • the electrode thus produced was tested under the same conditions as in Example 1.
  • the initial terminal voltage was 3.0 V, after 10 days it was still 3.0 V.
  • the electrode was reinserted, with an initial terminal voltage of 2.6 V and a final voltage of 10 days again set 3.0 V.
  • the start terminal voltage was 3.0 V and the end terminal voltage was 3.3 V.
  • the amount of manganese applied was only 0.7 g / dm 2 of manganese, and the annealing was carried out for 1 hour at 950 ° C. in a high vacuum.
  • the terminal voltage was 2.8 V at the beginning and 3.3 V at the end.
  • An electrode base consisting of 8 mm sintered titanium was placed in distilled water for 24 hours and then immediately cathodically loaded with 2 g / dm 2 manganese in an electrolysis bath as in Example 2. After removing the sintered titanium electrode from this electrolysis bath, it was washed again in slowly flowing water for 24 hours and then dried at 110 ° C. The electrode was then annealed in a high vacuum at 950 ° C. for 1.5 hours and finally used for the EMD deposition. The start terminal voltage was 2.8 V, the end terminal voltage after 10 days 3.0 V. After 28 electrolysis cycles, an end terminal voltage of 3.2 V was measured.
  • a mixture of 50% by weight of zirconium powder with a grain size of less than 100 I-Lm and 50% by weight of manganese powder with a grain size of less than 60 I-Lm was pasted with a little methyl cellulose in water to a pulpy mass and leveled on sintered zirconia plates with a thickness of 6 mm. Each side received about 5.0 g per dm 2 . After drying at 90 ° C, sintering was carried out at 1100 ° C for 2 hours under an argon atmosphere.
  • Sintering achieves an intimate connection, with some of the manganese also diffusing into the interior of the sintered zircon core, thus leading to the desired distribution.
  • the electrodeposition of manganese dioxide was carried out under the same conditions as in Example 6. After 15 electrolysis cycles, there was an average current yield of 95% and cell voltages between 1.9 and 2.2 V during the electrolysis period of 10 days each.
  • the advantages of the subject matter of the invention consist primarily in the fact that the anodes can be formed on the pure, still ductile valve metal, which is not possible with alloys with higher manganese contents, which are known to be brittle and cannot be processed. Furthermore, the anodes according to the invention retain a tough, elastic core made of pure metal, as a result of which the resistance of the anodes to mechanical loads, such as bending or impact, is significantly improved in comparison to anodes which consist of solid manganese alloys.
  • Another advantage is the lower manufacturing costs compared to precious metal activated anodes.
  • the following pictures 1 and 2 show profiles of manganese concentrations in titanium sheets, viewed from the sheet surface. These profiles were determined using an electron beam microsensor.
  • Figure 1 shows the course of the manganese concentration as a function of the annealing time.
  • Figure 2 shows manganese profiles depending on the amount of manganese originally applied to the surface.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
EP84115214A 1983-12-21 1984-12-12 Aktivierte Metallanoden sowie ein Verfahren zu deren Herstellung Expired EP0148439B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19833346093 DE3346093A1 (de) 1983-12-21 1983-12-21 Aktivierte metallanoden sowie ein verfahren zu deren herstellung
DE3346093 1983-12-21

Publications (3)

Publication Number Publication Date
EP0148439A2 EP0148439A2 (de) 1985-07-17
EP0148439A3 EP0148439A3 (en) 1986-07-16
EP0148439B1 true EP0148439B1 (de) 1988-07-27

Family

ID=6217492

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84115214A Expired EP0148439B1 (de) 1983-12-21 1984-12-12 Aktivierte Metallanoden sowie ein Verfahren zu deren Herstellung

Country Status (9)

Country Link
US (1) US4589960A (ja)
EP (1) EP0148439B1 (ja)
JP (1) JPS60187690A (ja)
BR (1) BR8406640A (ja)
DE (2) DE3346093A1 (ja)
ES (1) ES8600789A1 (ja)
GR (1) GR82513B (ja)
IE (1) IE55862B1 (ja)
ZA (1) ZA849918B (ja)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4683648A (en) * 1984-12-21 1987-08-04 Allied Corporation Lead-titanium, bipolar electrode in a lead-acid battery
DE3516523A1 (de) * 1985-05-08 1986-11-13 Sigri GmbH, 8901 Meitingen Anode fuer elektrochemische prozesse
DE4123291C2 (de) * 1991-07-13 1993-12-09 Blasberg Oberflaechentech Verwendung von Anoden für die galvanische Verchromung
CN101603180B (zh) * 2009-06-09 2011-01-19 湖南泰阳新材料有限公司 一种电解二氧化锰生产用涂层钛阳极的制备方法
CN101694001B (zh) * 2009-10-10 2011-05-18 中信大锰矿业有限责任公司 电解二氧化锰用Ti-Mn渗层钛阳极极板的制备方法

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU484893A1 (ru) * 1973-05-14 1975-09-25 Грузинский Ордена Трудового Красного Знамени Политехнический Институт Им.В.И.Ленина Материал анода дл электролитического получени двуокиси марганца
US4140617A (en) * 1976-05-25 1979-02-20 Dzhaparidze Levan N Anode for producing electrolytic manganese dioxide
DE2645414C2 (de) * 1976-10-08 1986-08-28 Hoechst Ag, 6230 Frankfurt Titananoden für die elektrolytische Gewinnung von Mangandioxid, sowie ein Verfahren zur Herstellung dieser Anoden
DE2734162C2 (de) * 1977-07-28 1986-10-16 Institut neorganičeskoj chimii i elektrochimii Akademii Nauk Gruzinskoj SSR, Tbilisi Elektrochemisches Verfahren zur Herstellung von Mangandioxid
FR2460343A1 (fr) * 1979-06-29 1981-01-23 Solvay Cathode pour la production electrolytique d'hydrogene
US4235697A (en) * 1979-10-29 1980-11-25 Diamond Shamrock Corporation Oxygen selective anode
US4342792A (en) * 1980-05-13 1982-08-03 The British Petroleum Company Limited Electrodes and method of preparation thereof for use in electrochemical cells
US4549943A (en) * 1984-11-01 1985-10-29 Union Carbide Corporation Suspension bath and process for production of electrolytic manganese dioxide

Also Published As

Publication number Publication date
DE3472980D1 (en) 1988-09-01
GR82513B (en) 1985-04-08
DE3346093A1 (de) 1985-09-05
US4589960A (en) 1986-05-20
EP0148439A2 (de) 1985-07-17
BR8406640A (pt) 1985-10-15
IE55862B1 (en) 1991-01-30
IE843269L (en) 1985-06-21
ZA849918B (en) 1985-08-28
ES538985A0 (es) 1985-11-01
ES8600789A1 (es) 1985-11-01
JPS60187690A (ja) 1985-09-25
EP0148439A3 (en) 1986-07-16

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