DE1207358B - Cathode for an alkali chloride electrolysis cell operating according to the diaphragm process - Google Patents

Description

For healing vpp Ch ₅ IOr, alkali and *** » * . .

a _S ser ^ tprf-% r _P >-; e | ktrplytisphe ZerSr | those who work by biarrheal processes

ajjipftlpridl ^ rigen P ^ CI, 'ICC |) jäind "for a long time alkali chloride electrolysis cell

sp ^ eji ^ fi ^ Ijiapjjragmenzeiten "b ^ kapnt, 'bei' ßeneii \

on the anodes, which are mostly made of graphite, gas 5 '' "" '

shaped chlorine and an <äe.ß mostly made of iron or applicant:

existing cathodes with the formation of Dr. Ludwig Kandter, Munich, Bräutigamstr. 18th

gn | m plektrolyte gaseous hydrogen -'- """* ^ιΓΓΠΐ '''' ^ '^''^"-'

eht. '' Anpaen- und ^ ath'odenrä'um'syerden'zjyeck- - ~~~ ""'~ .r \ " ' -—- ~ · -

$ ^ igersSis ^ mlt $ fe'eji $ "b'iaph'ragmäs yopein- io ^{As Erfuider benanot:}

apder "separated, 'ϊε nacli Strpmiiicfitl'uij ^' Tejnppfatur Dr- Ludwig Kandier, Munich

work on the rare cells with one. Spannuiig be- ^-::: =

| phen "3 \\ $$ 4YpIt, 'oljwphl dig fheoretiscfie Zer- 2

^ etzupg ^ soan'uupg from A | kalichlpri, a about 2.3 volts ■■

tejxäge.'Dpr Mäirbedarf eq * | jpannuug is * due to the yeast release of the! aluminum

cmrch '"^^" Qfjmschen ^ ipersTan ^^ iflrierhalb "des or Ziriks bäef'Hagriesiunis in & eiB" er "" A | lca! i-

ple ^ trpiyten and 'yqr' alleni äijrch the 'so-called lye is activated. This method "is first

Opera spaiinung to the piektrp'de'rij irisBesofläere to cumbersome and expensive, and secondly it is very

qef Wagserstiiff 'developeina ^ athöd ^. "^' 'spherical, in this way large-area electrodes, 'The aim (| he invention' is an electrical system that can also be used with ao such as

Ijolier ka ^ odigcter exposure as low as possible super-cells are desired, he1rstp [en

"tension aufwei§f:, ' fun ' the Alkajicfifpridelektro- species are so far only m a size up to about 10 cni?

lyse b * ei fi} edngeref Zellerispannüng ^ als'bVi'Verwen- bei ^ npt. ~ """."

In contrast, the electroderj according to FIG Cathodes operated and thereby 'an energy gain 35 Erfnduiig', 4 {e the same "^ tension reduction

can advertise achieved. or the equivalent energy delay errüogjichetf like

The water voltage depends on the "mentioned" pSK electrodes, in '§ehF' more simply

Current density '"known from" the' kind 'of the' * elec- way * in any desired 'form'urid size he-

Trodenmaterials and its surface properties are made, whereby the diaphragm cells very away. It is highest on smooth surfaces. 30 become much more economical.

In the German Auslegeschrift 1009 172 is a The cathode of the invention for one after Process for the electrical use of the decomposition diaphragm process working alkali chloride electrical energy of amalgams in the alkali chloride trolysis cell, the active substance being nickel or iron Electrolysis according to the amalgam process described in fine distribution and possibly also silver ben. If the amalgam decomposition cell contains a 35 or platinum or palladium, it is hydrogen Developing cathode is used, which indicates that it is made of a metallic conductive material consists of porous sintered nickel or iron powder or porous framework body, the pores of which through There is a mixture of these. Electrolytic deposition from an acidic nickel is present on such electrodes the hydrogen overvoltage is much smaller or iron nitrate solution with nickel or iron ais on smooth electrodes. They are therefore also filled as 40 hydroxyds and these hydroxides on cathodes for diaphragm cells this is advantageous afterwards, if necessary after a previous oxy-reversible. dation of the metal to higher valence levels, with From the German Auslegeschrift 1 094 249 it is known to be a gaseous reducing agent to metal, the so-called DSK electrodes have been cathodized, with the in the finely divided metal stored in the diaphragm cells for the alkali chloride 45 pores to use electrolysis. These DSK electrodes are chemically platinum in a manner known per se are made by depositing a powdered alloy or palladium. tion of aluminum or zinc or magnesium with the storage of metal hydroxides in the pores Iron and / or nickel is mixed with one of the framework bodies can be done in the following way, finely divided carrier metal, preferably iron 50 between a soluble or insoluble anode and or nickel, the mixture under high pressure with the framework body as a cathode becomes an electrolysis pressed and then sintered and the so obtained carried out in an acidic electrolyte, which the

10

Contains metal ions that are to be deposited as hydroxides, and also reducible ions contains, the redox potential of which is more positive than the deposition potential of the metal ions, with im Electrolyte space outside the cathode a pH value of the electrolyte is maintained that does not have any Metal hydroxide precipitation in the electrolyte allows. In this way, in the pores of the framework body the hydroxides deposited, which are present in an unusually fine distribution.

If the finely divided, produced by this process, in the pores of a framework Fixed hydroxides of nickel or iron are converted into metals by reduction these metals fixed in the pores of the framework also obtained in extremely fine distribution. On the resulting finely distributed Metals, more noble metals can be deposited, for example by being known per se Way soak the framework body with a platinum or palladium salt solution.

The porous layer, which is filled according to the invention with, the finely divided metal, can be on a "compact carrier, for example made of nickel or iron, be applied, which can also be perforated, or it thin film layers are used, which z. B. by spot welding od. Like. On a compact Underlay, which can optionally be perforated, can be applied, or it will be film-thin Layers alone, possibly supported by a grid, are used in which due to the porous Structure part of the gas evolution takes place on the back.

example

35

A material was used for the cathode of a diaphragm cell for alkali chloride electrolysis which was obtained in the following way:

A framework made of porous sintered nickel powder in the form of a plate about 0.7 mm thick was _{connected as the cathode in an acidic aqueous solution of nickel nitrate (100 gNiNO 3} ^ H ₂ O per liter), while a sheet of nickel served as the anode. The electrolysis was carried out at a current density of 0.5 Amp./dm ² until the pore spaces of the framework were filled from the inside to the outside with green divalent nickel hydroxide (about 6 hours). During the electrolysis, the pH of the electrolyte was kept in the acidic range (pH = 3). After washing out with water, the electrode was treated with flowing hydrogen at 250 ° C. for 8 hours. The subsequent cooling was also carried out under a hydrogen atmosphere.

With the electrode produced in this way, an electrolysis cell was built up for the decomposition of an NaCl solution, a graphite electrode serving as the anode and the electrode produced as described as the cathode. The anode and cathode compartments were separated by a diaphragm. When using the electrode according to the invention, the voltage in the NaCl decomposition cell can be reduced by 0.4 Volts at a current density of 20 amps / dm ² compared to an NaCl decomposition cell in which a smooth Ni sheet is used as the cathode.

Claims (1)

Claim: Cathode for an alkali chloride electrolysis cell working according to the diaphragm process, the active substance nickel or iron in fine distribution and possibly also silver or Contains platinum or palladium, characterized in that it consists of a metallic conductive porous framework body, whose pores are made by electrolytic deposition an acidic nickel or iron nitrate solution filled with nickel or iron hydroxide and wherein these hydroxides then, optionally after previous oxidation of the metal, to higher levels Valence levels that have been reduced to metal with a gaseous reducing agent, optionally on the finely divided metal embedded in the pores on chemical Ways platinum or palladium has been deposited in a manner known per se. Considered publications:
German publication No. 1094 249. 509 759/378 12.65 © Bundesdruckerei Berlin