EP0042984B1 - Electrode free from noble metals and process for its manufacture - Google Patents
Electrode free from noble metals and process for its manufacture Download PDFInfo
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- EP0042984B1 EP0042984B1 EP81104207A EP81104207A EP0042984B1 EP 0042984 B1 EP0042984 B1 EP 0042984B1 EP 81104207 A EP81104207 A EP 81104207A EP 81104207 A EP81104207 A EP 81104207A EP 0042984 B1 EP0042984 B1 EP 0042984B1
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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
- C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
Definitions
- titanium anodes with active metal-containing active layers or graphite electrodes are generally used today. These so-called dimensionally stable titanium anodes have the advantage over the graphite electrodes that the external dimensions do not change during operation.
- the disadvantage of these anodes is the relatively high production costs due to the use of noble metal in the active layer.
- magnetite can be used as an anode material for the separation of chlorine, but this material has a very high overvoltage with regard to chlorine, so that its use has been discontinued for a long time due to the high energy consumption.
- an electrode consisting predominantly of trivalent iron oxide with additions of one or more metal oxides is described.
- an oxide mixture is obtained from an iron salt solution via a carrier precipitation, which is then pressed and sintered in an oxygen-containing atmosphere.
- Titanium dioxide, zirconium dioxide and / or tin dioxide are mentioned as additional oxides.
- this electrode has a separation potential for chlorine of 1.65 V GKE (measured against saturated calomel electrode) at a current density of 1 kA / m 2 , which corresponds to a chlorine separation voltage of 1.9 V based on the normal hydrogen potential.
- the deposition potential increases considerably, so that this electrode achieves an impermissibly high deposition potential at the current densities of 1.5 to 2.0 kA / m 2 that are currently used in technical systems.
- DE-OS 2 320 883 describes anodes which consist of sintered bodies with a spinel structure of the general formula M x Fe 3 - x 0 4 and are said to be suitable as chlorine anodes.
- M means a metal from the group consisting of manganese, nickel, cobalt, magnesium, copper, zinc and / or cadmium and x stands for 0.05 to 0.4.
- electrodes which consist of an electrically conductive substrate to which a single metal spinel of the formula C 03 0 4 is applied as an electrochemically active substance, and additionally modifying oxides of groups IIIB -VIIB, IIIA-VA, and may contain lanthanides or actinides.
- the deposition potential of these electrodes also does not meet the technical requirements.
- the object of the present invention was to provide electrodes whose electrochemically active layer contains spinels which are particularly suitable as anodes for the separation of chlorine in electrolysis cells and which, in addition to good corrosion resistance to the electrolyte and the electrolysis products, combined with a long service life , have a low separation voltage for chlorine.
- the electrode according to the invention contains the two spinels as individual spinels and that they do not form a mixed spinel.
- the presence of the two substances next to one another can be proven in a known manner by means of an X-ray fine structure analysis.
- the active layer preferably has the two spinels in a weight ratio of Fe 3 0 4 to Co 3 0 4 of 40:60 to 70:30.
- the active layer can be on an electrically conductive carrier, e.g. B. a valve metal, graphite, magnetite.
- an electrically conductive carrier e.g. B. a valve metal, graphite, magnetite.
- H the entire thickness of the electrode consists of the active layer.
- the electrodes according to the invention are produced under conditions such that mixed spinel formation cannot take place, special conditions being observed since C 03 0 4 tends to be slightly divalent in cobalt oxide and conversely Fe 3 0 4 has a tendency to be slightly trivalent Iron oxide to form a cobalt-iron mixing spinel.
- a suitable method to achieve this goal is the plasma spraying process.
- the two powdered spinels are mixed thoroughly before processing. You should expediently have grain sizes of 10 to 200 microns, preferably ⁇ 125 microns.
- the mixture is then placed in the reservoir of a plasma spray gun, moving towards it It is important to ensure that no segregation occurs both during metering and during transport.
- a conventional plasma spraying system can be used for the coating, with either argon alone or argon in a mixture with up to 10% by volume hydrogen being considered as carrier gas. It is also essential that the plasma spraying system is operated in a low energy range, ie that values of 30 kW are not exceeded, with a minimum amount of 6 kW being adhered to for design reasons.
- the body to be coated should be degreased in a known manner beforehand and then the surface by sandblasting, pickling and the like. be prepared.
- the distance between the plasma flame and the body to be coated should suitably be 7 to 12 cm.
- the plasma flame is moved back and forth in front of the body to be coated until the spray layer has reached the desired thickness.
- the active layer is effective even with a relatively small thickness of 20 to 30 ⁇ m, although of course much thicker layers are permissible, up to electrodes which consist exclusively of the electrochemically active material.
- a powder of a valve metal can also be added to the spinel mixture to be sprayed.
- other substances can also be added if special properties are desired and if these other substances do not impair the electrochemical activity of the spinel layer.
- the electrodes according to the invention show a chlorine separation potential of 1395 mV at current densities of 0.15 kA / m 2 , based on the normal H 2 electrode, ie the overvoltage is only approx. 35 mV.
- the electrodes are characterized by a low overvoltage, with the deposition potential at 1.5 kA / m 2 depending on the substrate between approximately 1450 and maximum are around 1600 mV.
- the electrodes according to the invention are notable for good chemical and mechanical resistance, and even if graphite is used as the substrate, practically no erosion can be ascertained even with longer standing times.
- the anodes produced in this way are subjected to a voltage test under the operating conditions of the chlor-alkali electrodes.
- the following deposition potentials are measured (against H z normal electrode):
- An active layer of Fe 3 0 4 to C 03 0 4 (weight ratio 70:30) is applied to a base body made of electrographite with the dimensions of the electrode area of 20 x 15 x 10 mm.
- Argon serves as the carrier gas, the injection energy is 18 kW and the distance of the plasma flame from the electrographite base body is 9 cm.
- a powder mixture of Fe 3 O 4 to CO 3 O 4 im is placed on an aluminum sheet of size 20 x 15 x 1.5 mm with the help of a plasma flame with argon as carrier gas with an injection energy of 17 kW, at a distance of 10 cm from the plasma flame / base body weight ratio of 66 2/3: 33 1/3, the 70 wt .-% of titanium powder was added sprayed on. After a layer thickness of 1.5 mm has been reached, the coating process is stopped, the sprayed-on layer is detached from the aluminum and the negative mold thus produced is measured as an electrode. The following separation potentials are determined:
- a comparison of these deposition voltages measured at 1.5 kA / m 2 with the deposition voltages measured in Examples 1 to 4 in the electrodes according to the invention shows a difference of more than 250 mV.
- This electrode also has a deposition potential increased by approximately 200 mV at 1.5 kA / m 2 compared to the electrodes according to the invention.
- the anode is produced as described in Example 1, argon being used as the plasma gas at an injection energy of 32 kW.
- the weight ratio Fe 3 0 4 to C 03 0 4 (grain size ⁇ 125 ⁇ m) is 70:30.
- the deposition potential is determined under the same conditions as in Examples 1 to 4. The following values are determined:
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Description
Bei der Herstellung von Chlor oder Chlorverbindungen durch Elektrolyse wäßriger Natrium- bzw. Kaliumchloridlösungen werden heute im allgemeinen Titananoden mit edelmetallhaltigen Aktivschichten oder Graphitelektroden eingesetzt. Diese sogenannten dimensionsstabilen Titananoden haben gegenüber den Graphitelektroden den Vorteil, daß sich die äußeren Abmessungen während des Betriebs nicht ändern. Der Nachteil dieser Anoden liegt in den relativ hohen Herstellungskosten, bedingt durch die Verwendung von Edelmetall in der Aktivschicht.In the manufacture of chlorine or chlorine compounds by electrolysis of aqueous sodium or potassium chloride solutions, titanium anodes with active metal-containing active layers or graphite electrodes are generally used today. These so-called dimensionally stable titanium anodes have the advantage over the graphite electrodes that the external dimensions do not change during operation. The disadvantage of these anodes is the relatively high production costs due to the use of noble metal in the active layer.
Es ist auch bekannt, daß man Magnetit als Anodenmaterial zur Abscheidung von Chlor einsetzen kann, jedoch besitzt dieses Material bezüglich Chlor eine sehr hohe Überspannung, so daß seine Verwendung aufgrund des hohen Energieverbrauchs bereits seit längerer Zeit eingestellt wurde.It is also known that magnetite can be used as an anode material for the separation of chlorine, but this material has a very high overvoltage with regard to chlorine, so that its use has been discontinued for a long time due to the high energy consumption.
Es hat jedoch nicht an Versuchen gefehlt, auf der Basis des wesentlich preiswerteren Eisenoxids edelmetallfreie Elektroden bereitzustellen, die einerseits eine technisch und wirtschaftlich befriedigende niedrige Abscheidespannung aufweisen und andererseits gleichzeitig eine für Chlor ausreichende chemische Beständigkeit aufweisen.However, there has been no shortage of attempts to provide non-precious metal electrodes on the basis of the much cheaper iron oxide, which on the one hand have a technically and economically satisfactory low deposition voltage and on the other hand have sufficient chemical resistance for chlorine.
So wird in der DDR-Patentschrift 98 838 eine vorwiegend aus dreiwertigem Eisenoxid mit Zusätzen von einem oder mehreren Metalloxiden bestehende Elektrode beschrieben. Zur Herstellung dieser Elektrode wird aus einer Eisensalzlösung über eine Trägerfällung ein Oxidgemisch erhalten, das anschließend verpreßt und in sauerstoffhaltiger Atmosphäre gesintert wird. Als Zusatzoxide werden Titandioxid, Zirkondioxid und/oder Zinndioxid genannt. Diese Elektrode besitzt jedoch ein Abscheidepotential für Chlor von 1,65 V GKE (gemessen gegen gesättigte Kalomel-Elektrode), bei einer Stromdichte von 1 kA/m2, was bezogen auf das Wasserstoffnormalpotential einer Chlorabscheidespannung von 1,9V entspricht. Mit zunehmender Stromdichte erhöht sich das Abscheidepotential beträchtlich, so daß diese Elektrode bei den in technischen Anlagen derzeit üblicherweise angewandten Stromdichten von 1,5 bis 2,0 kA/m2 ein unzulässig hohes Abscheidepotential erreicht.Thus, in the GDR patent 98 838 an electrode consisting predominantly of trivalent iron oxide with additions of one or more metal oxides is described. To produce this electrode, an oxide mixture is obtained from an iron salt solution via a carrier precipitation, which is then pressed and sintered in an oxygen-containing atmosphere. Titanium dioxide, zirconium dioxide and / or tin dioxide are mentioned as additional oxides. However, this electrode has a separation potential for chlorine of 1.65 V GKE (measured against saturated calomel electrode) at a current density of 1 kA / m 2 , which corresponds to a chlorine separation voltage of 1.9 V based on the normal hydrogen potential. With increasing current density, the deposition potential increases considerably, so that this electrode achieves an impermissibly high deposition potential at the current densities of 1.5 to 2.0 kA / m 2 that are currently used in technical systems.
In der DE-OS 2 320 883 werden Anoden beschrieben, die aus gesinterten Körpern mit Spinellstruktur der allgemeinen Formel MxFe3-x04 bestehen und als Chloranoden geeignet sein sollen. In dieser Formel bedeutet M ein Metall aus der Gruppe Mangan, Nickel, Kobalt, Magnesium, Kupfer, Zink und/oder Cadmium und x steht für 0,05 bis 0,4. Bei diesen Elektroden wird besonders auf die verbesserte Korrosionsbeständigkeit im Vergleich zu herkömmlichen Magnetitelektroden hingewiesen, während auf die für die Beurteilung einer Elektrode wesentlichen Abscheidepotentiale nicht abgehoben wird. Wie eigene Untersuchungen (vgl. Vergleichsbeispiel 1) gezeigt haben, liegen diese Abscheidepotentiale bei technisch gebräuchlichen Stromdichten von 1,5 kA/m2, bei 1750 bis 2000 mV (gemessen gegen H2-Normalelektrode).DE-OS 2 320 883 describes anodes which consist of sintered bodies with a spinel structure of the general formula M x Fe 3 - x 0 4 and are said to be suitable as chlorine anodes. In this formula, M means a metal from the group consisting of manganese, nickel, cobalt, magnesium, copper, zinc and / or cadmium and x stands for 0.05 to 0.4. With these electrodes, particular reference is made to the improved corrosion resistance compared to conventional magnetite electrodes, while the deposition potentials which are essential for the assessment of an electrode are not emphasized. As our own investigations (cf. Comparative Example 1) have shown, these deposition potentials are at technically customary current densities of 1.5 kA / m 2 , at 1750 to 2000 mV (measured against normal H 2 electrodes).
In den US-PS 3 977 958 und 4 142 005 werden Elektroden beschrieben, die aus einem elektrisch leitenden Substrat bestehen, auf das ein Einzelmetall - spinell der Formel C0304 als elektrochemisch aktive Substanz aufgebracht ist, der zusätzlich modifizierende Oxide der Gruppen IIIB-VIIB, IIIA-VA, sowie der Lanthaniden oder Actiniden enthalten kann. Aber auch die Abscheidepotentiale dieser Elektroden genügen nicht den technischen Anforderungen.In US Pat. Nos. 3,977,958 and 4,142,005, electrodes are described which consist of an electrically conductive substrate to which a single metal spinel of the formula C 03 0 4 is applied as an electrochemically active substance, and additionally modifying oxides of groups IIIB -VIIB, IIIA-VA, and may contain lanthanides or actinides. However, the deposition potential of these electrodes also does not meet the technical requirements.
Der vorliegenden Erfindung lag die Aufgabe zugrunde, Elektroden bereitzustellen, deren elektrochemisch aktive Schicht Spinelle enthält, die vor allem als Anoden für die Abscheidung von Chlor in Elektrolysezellen geeignet sind und die neben einer guten Korrosionsbeständigkeit gegenüber dem Elektrolyten und den Elektrolyseprodukten, verbunden mit einer hohen Standdauer, eine niedrige Abscheidespannung für Chlor aufweisen.The object of the present invention was to provide electrodes whose electrochemically active layer contains spinels which are particularly suitable as anodes for the separation of chlorine in electrolysis cells and which, in addition to good corrosion resistance to the electrolyte and the electrolysis products, combined with a long service life , have a low separation voltage for chlorine.
Es wurde gefunden, daß diese Aufgabe durch eine spinellhaltige Elektrode gelöst wird, bei der die Spinelle aus einem Gemisch der Einzelspinelle des Eisens und Kobalts bestehen mit der Maßgabe, daß das Gewichtsverhältnis Eisenspinell zu Kobaltspinell von 30 : 70 bis 90 : 10 beträgt.It has been found that this object is achieved by an electrode containing spinel, in which the spinels consist of a mixture of the individual spinels of iron and cobalt, with the proviso that the weight ratio of iron spinel to cobalt spinel is from 30:70 to 90:10.
Wesentlich ist, daß die erfindungsgemäße Elektrode die beiden Spinelle als Einzelspinelle enthält und diese keinen Mischspinell bilden. Das Vorliegen der beiden Substanzen nebeneinander kann auf bekannte Weise durch eine Röntgenfeinstrukturanalyse nachgewiesen werden.It is essential that the electrode according to the invention contains the two spinels as individual spinels and that they do not form a mixed spinel. The presence of the two substances next to one another can be proven in a known manner by means of an X-ray fine structure analysis.
Vorzugsweise weist die aktive Schicht die beiden Spinelle in einem Gewichtsverhältnis von Fe304 zu Co304 von 40 : 60 bis 70 : 30 auf.The active layer preferably has the two spinels in a weight ratio of Fe 3 0 4 to Co 3 0 4 of 40:60 to 70:30.
Die Aktivschicht kann auf einen elektrisch leitenden Träger, z. B. einem Ventilmetall, Graphit, Magnetit, aufgebracht sein. Es ist aber auch möglich, auf dieses Substrat ganz zu verzichten, d. h. daß die Elektrode in ihrer gesamten Stärke aus der Aktivschicht besteht.The active layer can be on an electrically conductive carrier, e.g. B. a valve metal, graphite, magnetite. However, it is also possible to dispense with this substrate entirely; H. that the entire thickness of the electrode consists of the active layer.
Die Herstellung der erfindungsgemäßen Elektroden erfolgt unter solchen Bedingungen, daß eine Mischspinellbildung nicht stattfinden kann, wobei besondere Bedingungen zu beachten sind, da C0304 die Tendenz hat, leicht in zweiwertiges Kobaltoxid und umgekehrt Fe304 die Tendenz hat, leicht in dreiwertiges Eisenoxid, unter Bildung eines Kobalt-Eisen-Mischspinells überzugehen.The electrodes according to the invention are produced under conditions such that mixed spinel formation cannot take place, special conditions being observed since C 03 0 4 tends to be slightly divalent in cobalt oxide and conversely Fe 3 0 4 has a tendency to be slightly trivalent Iron oxide to form a cobalt-iron mixing spinel.
Ein geeignetes Verfahren, um dieses Ziel zu erreichen, ist das Plasma-Spritzverfahren. Hierzu werden die beiden in Pulverform vorliegenden Spinelle vor der Verarbeitung gründlich gemischt. Sie sollten zweckmäßig Korngrößen von 10 bis 200 µm, vorzugsweise von < 125 µm, aufweisen. Die Mischung wird dann in den Vorratsbehälter einer Plasma-Spritzpistole eingegeben, wobei darauf zu achten ist, daß sowohl bei der Eindosierung als auch beim Transport keine Entmischung eintritt. Für die Beschichtung kann eine übliche Plasma-Spritzanlage verwendet werden, wobei als Trägergas entweder Argon allein oder Argon im Gemisch mit bis zu 10 Vol.-% Wasserstoff in Betracht kommen. Wesentlich ist ferner, daß die Plasma-Spritzanlage in einem niederen Energiebereich betrieben wird, d. h. daß Werte von 30 kW nicht überschritten werden, wobei aus konstruktiven Gründen ein Mindestbetrag von 6 kW eingehalten werden sollte.A suitable method to achieve this goal is the plasma spraying process. To do this, the two powdered spinels are mixed thoroughly before processing. You should expediently have grain sizes of 10 to 200 microns, preferably <125 microns. The mixture is then placed in the reservoir of a plasma spray gun, moving towards it It is important to ensure that no segregation occurs both during metering and during transport. A conventional plasma spraying system can be used for the coating, with either argon alone or argon in a mixture with up to 10% by volume hydrogen being considered as carrier gas. It is also essential that the plasma spraying system is operated in a low energy range, ie that values of 30 kW are not exceeded, with a minimum amount of 6 kW being adhered to for design reasons.
Der zu beschichtende Körper sollte in bekannter Weise vorher entfettet und anschließend die Oberfläche durch Sandstrahlen, Beizen u. dgl. vorbereitet werden.The body to be coated should be degreased in a known manner beforehand and then the surface by sandblasting, pickling and the like. be prepared.
Der Abstand zwischen Plasmaflamme und zu beschichtendem Körper sollte zweckmäßig 7 bis 12 cm betragen. Die Plasmaflamme wird vor dem zu beschichtenden Körper so lange hin und her bewegt, bis die Spritzschicht die gewünschte Dicke erreicht hat. Die Aktivschicht ist bereits bei einer relativ geringen Dicke von 20 bis 30 µm wirksam, wobei selbstverständlich auch wesentlich dickere Schichten zulässig sind, bis zu Elektroden die ausschließlich aus dem elektrochemisch aktiven Material bestehen.The distance between the plasma flame and the body to be coated should suitably be 7 to 12 cm. The plasma flame is moved back and forth in front of the body to be coated until the spray layer has reached the desired thickness. The active layer is effective even with a relatively small thickness of 20 to 30 µm, although of course much thicker layers are permissible, up to electrodes which consist exclusively of the electrochemically active material.
Zur Erhöhung der Auftragsleistung der Plasma-Spritzanlage kann man dem zu verspritzenden Spinell-Gemisch auch ein Pulver eines Ventilmetalls zusetzen. Selbstverständlich können auch andere Substanzen zugesetzt werden, sofern besondere Eigenschaften gewünscht werden und sofern diese anderen Substanzen die elektrochemische Aktivität der Spinellschicht nicht beeinträchtigen.To increase the application rate of the plasma spraying system, a powder of a valve metal can also be added to the spinel mixture to be sprayed. Of course, other substances can also be added if special properties are desired and if these other substances do not impair the electrochemical activity of the spinel layer.
Die erfindungsgemäßen Elektroden zeigen, als Anoden bei der Elektrolyse von wäßrigen Alkalimetall-Chlorid-Lösungen eingesetzt, bei Stromdichten von 0,15 kA/m2 ein Chlorabscheidepotential von 1395 mV, bezogen auf die H2-Normalelektrode, d. h. die Überspannung beträgt nur ca. 35 mV. Aber auch bei den technisch vor allen interessierenden höheren Stromdichten von 1,5 bis 6 kA/m2, sind die Elektroden durch eine niedrige Überspannung gekennzeichnet, wobei bei 1,5 kA/m2 die Abscheidepotentiale je nach Substrat zwischen ca. 1450 und maximal etwa 1600 mV liegen. Demgegenüber werden in der oben bereits zitierten DDR-Patentschrift 98 838 bei niedrigeren Stromdichten von 1,0 kA/m2 Abscheidepotentiale von 1650 bis 1730mV, gemessen gegen Kalomel-Elektrode, genannt, was einem Potential gegen die H2-Normalelektrode von ca. 1900 bis 1980 mV entspricht.When used as anodes in the electrolysis of aqueous alkali metal chloride solutions, the electrodes according to the invention show a chlorine separation potential of 1395 mV at current densities of 0.15 kA / m 2 , based on the normal H 2 electrode, ie the overvoltage is only approx. 35 mV. However, even at the higher current densities of 1.5 to 6 kA / m 2 , which are of technical interest above all, the electrodes are characterized by a low overvoltage, with the deposition potential at 1.5 kA / m 2 depending on the substrate between approximately 1450 and maximum are around 1600 mV. In contrast, in the GDR patent 98 838 already cited above, at lower current densities of 1.0 kA / m 2, deposition potentials of 1650 to 1730 mV, measured against a calomel electrode, are mentioned, which is a potential against the H 2 normal electrode of approx. 1900 up to 1980 mV.
Zudem zeichnen sich die erfindungsgemäßen Elektroden durch eine gute chemische und mechanische Widerstandsfähigkeit aus und sogar bei Verwendung von Graphit als Substrat kann auch bei längeren Standzeiten praktisch kein Abtrag festgestellt werden.In addition, the electrodes according to the invention are notable for good chemical and mechanical resistance, and even if graphite is used as the substrate, practically no erosion can be ascertained even with longer standing times.
- a) Auf ein Titan-Streckmetallgitter (11 x 6 x 2 x 1,5 mm) mit der geometrischen Fläche von ca. 20 cm2, welches mit einer zentralen elektrischen Ableitung aus Titan versehen ist, wird mit Hilfe eines Plasmabrenners ein Gemenge von Fe304 und C0304 im Gewichtsverhältnis 70 : 30 aufgebracht. Zur Verwendung kommen Pulver mit einer Korngröße im Bereich von < 125 µm und Argon als Trägergas bei einer Spritzenergie von 18 kW. Nach Durchführung von 3 Spritzzyklen pro Seite im Abstand von 90 mm beträgt die Schichtdicke 30 gm.a) On a titanium expanded metal grid (11 x 6 x 2 x 1.5 mm) with the geometric area of about 20 cm 2 , which is provided with a central electrical lead made of titanium, a mixture of Fe is using a plasma torch 3 0 4 and C 03 0 4 applied in a weight ratio of 70:30. Powders with a grain size in the range of <125 µm and argon as carrier gas with an injection energy of 18 kW are used. After 3 spraying cycles per side at a distance of 90 mm, the layer thickness is 30 gm.
- b) Unter sonst gleichen Bedingungen wird ein Gemenge von Fe304 und Co304 im Gewichtsverhältnis von 50 : 50 undb) Under otherwise identical conditions, a mixture of Fe 3 0 4 and Co 3 0 4 in a weight ratio of 50:50 and
- c) im Gewichtsverhältnis von 30 : 70 aufgebracht.c) applied in a weight ratio of 30:70.
Die auf diese Weise hergestellten Anoden werden unter den Betriebsbedingungen der Chloralkälielektroden einem Stromspannungstest unterzogen. Dabei werden folgende Abscheidepotentiale gemessen (gegen Hz-Normalelektrode):
-
a) Die Anode wird wie in Beispiel 1 beschrieben hergestellt, wobei als Plasmagas ein Gemisch aus 90 Vol.-% Ar, 10 Vol.-% H2 bei einer Spritzenergie von 17,2kW verwendet wird. Das Gewichtsverhältnis Fe304 zu C0304 (Korngröße < 125 µm) beträgt 90 : 10. Der Strom-Spannungstest zeigt folgende Ergebnisse:a) The anode is produced as described in Example 1, a mixture of 90% by volume Ar, 10% by volume H 2 and an injection energy of 17.2 kW being used as the plasma gas. The weight ratio Fe 3 0 4 to C 03 0 4 (grain size <125 µm) is 90:10. The current-voltage test shows the following results:
-
b) Bei einer Verwendung eines Plasmagases aus reinem Argon und einer Spritzenergie von 19,2 kW werden Anoden erhalten, die folgende Potentiale zeigen:b) When using a plasma gas made of pure argon and an injection energy of 19.2 kW, anodes are obtained which show the following potentials:
Auf einen Grundkörper aus Elektrographit mit den Abmessungen der Elektrodenfläche von 20 x 15 x 10 mm wird eine Aktivschicht aus Fe304 zu C0304 (Gewichtsverhältnis 70 : 30) aufgebracht. Als Trägergas dient Argon, die Spritzenergie beträgt 18 kW und der Abstand der Plasmaflamme von dem Elektrographitgrundkörper 9 cm.An active layer of Fe 3 0 4 to C 03 0 4 (weight ratio 70:30) is applied to a base body made of electrographite with the dimensions of the electrode area of 20 x 15 x 10 mm. Argon serves as the carrier gas, the injection energy is 18 kW and the distance of the plasma flame from the electrographite base body is 9 cm.
Die Bestimmung des Abscheidepotentials ergibt:
Werte des unter gleichen Bedingungen gemessenen Grundkörpers ohne Aktivierung:
Auf ein Aluminiumblech der Größe 20 x 15 x 1,5 mm wird mit Hilfe einer Plasmaflamme mit Argon als Trägergas bei einer Spritzenergie von 17 kW, bei einem Abstand Plasmaflamme/Grundkörper 10 cm eine Pulvermischung aus Fe3O4 zu CO3O4 im Gewichtsverhältnis 662/3 : 331/3, der 70 Gew.-% Titanpulver zugesetzt war, aufgespritzt. Nach Erreichen einer Schichtdicke von 1,5 mm wird der Beschichtungsvorgang abgebrochen, die aufgespritzte Schicht vom Aluminium abgelöst und die so hergestellte Negativform als Elektrode vermessen. Dabei werden folgende Abscheidepotentiale festgestellt:
Verbindungen des Typs MxFe3-XO4 (A=CO0,3Fe2,7O4 und B=CO0,4Fe2,6O4, entsprechend der DE-OS 2 320 883) werden analog Beispiel 1 mit Hilfe einer Plasmaspritzpistole auf einen entsprechenden Anodengrundkörper aus Titan aufgetragen und unter den gleichen Bedingungen wie in Beispiel 1 bis 4 beschrieben die Abscheidepotentiale bestimmt.Compounds of the type M x Fe 3 -XO 4 (A = CO 0.3 Fe 2.7 O 4 and B = CO 0.4 Fe 2.6 O 4, according to DE-OS 2 320 883) are made analogously to Example 1 applied with the aid of a plasma spray gun to a corresponding titanium anode body and the deposition potentials were determined under the same conditions as described in Examples 1 to 4.
Dabei werden folgende Werte ermittelt:
Ein Vergleich dieser bei 1,5 kA/m2 gemessenen Abscheidespannungen mit den in Beispielen 1 bis 4 gemessenen Abscheidespannungen bei den erfindungsgemäßen Elektroden zeigt eine Differenz von mehr als 250 mV.A comparison of these deposition voltages measured at 1.5 kA / m 2 with the deposition voltages measured in Examples 1 to 4 in the electrodes according to the invention shows a difference of more than 250 mV.
Wie in Beispiel 1 beschrieben, wird eine Elektrode hergestellt unter Verwendung von reinem C0304 (entsprechend US-PS 3 977 958). Der Stromspannungstest zeigt folgende Ergebnisse:
Auch diese Elektrode zeigt gegenüber den erfindungsgemäßen Elektroden ein um ca. 200 mV erhöhtes Abscheidepotential bei 1,5 kA/m2.This electrode also has a deposition potential increased by approximately 200 mV at 1.5 kA / m 2 compared to the electrodes according to the invention.
Die Anode wird wie in Beispiel 1 beschrieben hergestellt, wobei als Plasmagas Argon bei einer Spritzenergie von 32 kW verwendet wird. Das Gewichtsverhältnis Fe304 zu C0304 (Korngröße < 125 µm) beträgt 70 : 30. Die Bestimmung des Abscheidepotentials erfolgt unter den gleichen Bedingungen wie in Beispiel 1 bis 4. Dabei werden folgende Werte ermittelt:
Ein Vergleich dieser Abscheidepotentiale mit den Abscheidepotentialen der Elektrode gemäß Beispiel 1a, deren aktive Schicht mit einer Spritzenergie von 18 kW hergestellt worden ist, ergibt, daß letztere ein um 90 bis 170 mV niedrigeres Abscheidepotential besitzt.A comparison of these deposition potentials with the deposition potentials of the electrode according to Example 1a, the active layer of which was produced with an injection energy of 18 kW, shows that the latter has a deposition potential which is 90 to 170 mV lower.
Claims (6)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19803024611 DE3024611A1 (en) | 1980-06-28 | 1980-06-28 | NON-METAL ELECTRODE |
| DE3024611 | 1980-06-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0042984A1 EP0042984A1 (en) | 1982-01-06 |
| EP0042984B1 true EP0042984B1 (en) | 1983-08-17 |
Family
ID=6105944
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP81104207A Expired EP0042984B1 (en) | 1980-06-28 | 1981-06-02 | Electrode free from noble metals and process for its manufacture |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4411761A (en) |
| EP (1) | EP0042984B1 (en) |
| JP (1) | JPS5739184A (en) |
| DE (2) | DE3024611A1 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4546058A (en) * | 1984-12-12 | 1985-10-08 | Energy Research Corporation | Nickel electrode for alkaline batteries |
| US5356674A (en) * | 1989-05-04 | 1994-10-18 | Deutsche Forschungsanstalt Fuer Luft-Raumfahrt E.V. | Process for applying ceramic coatings using a plasma jet carrying a free form non-metallic element |
| US7247229B2 (en) * | 1999-06-28 | 2007-07-24 | Eltech Systems Corporation | Coatings for the inhibition of undesirable oxidation in an electrochemical cell |
| US7235161B2 (en) * | 2003-11-19 | 2007-06-26 | Alcoa Inc. | Stable anodes including iron oxide and use of such anodes in metal production cells |
| TWI433964B (en) | 2010-10-08 | 2014-04-11 | Water Star Inc | Multi-layer mixed metal oxide electrode and method for making same |
| NO2751376T3 (en) | 2014-02-13 | 2018-03-24 | ||
| DE102015010083A1 (en) | 2015-08-07 | 2017-02-09 | Friedrich-Schiller-Universität Jena | Redox flow cell for storing electrical energy and its use |
| DE102015014828A1 (en) | 2015-11-18 | 2017-05-18 | Friedrich-Schiller-Universität Jena | Hybrid flow cell for storing electrical energy and its use |
| US11668017B2 (en) | 2018-07-30 | 2023-06-06 | Water Star, Inc. | Current reversal tolerant multilayer material, method of making the same, use as an electrode, and use in electrochemical processes |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3706644A (en) * | 1970-07-31 | 1972-12-19 | Ppg Industries Inc | Method of regenerating spinel surfaced electrodes |
| US3711397A (en) * | 1970-11-02 | 1973-01-16 | Ppg Industries Inc | Electrode and process for making same |
| DD98838A1 (en) | 1972-01-06 | 1973-07-12 | ||
| GB1433805A (en) | 1972-04-29 | 1976-04-28 | Tdk Electronics Co Ltd | Methods of electrolysis using complex iron oxide electrodes |
| IT978528B (en) * | 1973-01-26 | 1974-09-20 | Oronzio De Nora Impianti | METALLIC ELECTRODES AND PROCEDURE FOR THEIR ACTIVATION |
| US3977958A (en) * | 1973-12-17 | 1976-08-31 | The Dow Chemical Company | Insoluble electrode for electrolysis |
| US4169028A (en) * | 1974-10-23 | 1979-09-25 | Tdk Electronics Co., Ltd. | Cathodic protection |
| JPS5541815Y2 (en) * | 1975-02-18 | 1980-09-30 | ||
| US4024044A (en) * | 1975-09-15 | 1977-05-17 | Diamond Shamrock Corporation | Electrolysis cathodes bearing a melt-sprayed and leached nickel or cobalt coating |
| DE2652293C2 (en) * | 1976-11-17 | 1978-09-14 | Uranit Uran-Isotopentrennungs- Gesellschaft Mbh, 5170 Juelich | Process for the formation of a corrosion-preventing, oxidic protective layer on steels, in particular maraging steels |
| US4142005A (en) * | 1976-02-27 | 1979-02-27 | The Dow Chemical Company | Process for preparing an electrode for electrolytic cell having a coating of a single metal spinel, Co3 O4 |
| US4061549A (en) * | 1976-07-02 | 1977-12-06 | The Dow Chemical Company | Electrolytic cell anode structures containing cobalt spinels |
| IL50217A (en) * | 1976-08-06 | 1980-01-31 | Israel State | Electrocatalytically acitve spinel type mixed oxides |
| FR2434213A1 (en) * | 1978-08-24 | 1980-03-21 | Solvay | PROCESS FOR THE ELECTROLYTIC PRODUCTION OF HYDROGEN IN AN ALKALINE MEDIUM |
-
1980
- 1980-06-28 DE DE19803024611 patent/DE3024611A1/en not_active Withdrawn
-
1981
- 1981-06-02 EP EP81104207A patent/EP0042984B1/en not_active Expired
- 1981-06-02 DE DE8181104207T patent/DE3160766D1/en not_active Expired
- 1981-06-24 US US06/276,985 patent/US4411761A/en not_active Expired - Fee Related
- 1981-06-26 JP JP9849281A patent/JPS5739184A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE3160766D1 (en) | 1983-09-22 |
| EP0042984A1 (en) | 1982-01-06 |
| US4411761A (en) | 1983-10-25 |
| JPS5739184A (en) | 1982-03-04 |
| DE3024611A1 (en) | 1982-01-28 |
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