Electrolyzer for basic solutions

Claim 2

Electrolyser comprising two electrodes, an anode and a cathode, said cathode comprising a catalyser basically containing cobalt and molybdenum, at least partly immersed in a basic electrolyte, with a separator being interposed between said electrodes, wherein said anode comprises a porous conductive material comprising sintered nickel impregnated with nickel hydroxide in a quantity such that the proportion by weight between the nickel hydroxide and the nickel lies between 50 and 75%.

Claim 3

Electrolyser according to claim 1, wherein said electrolyte comprises an aqueous alkaline solution whose concentration lies between normal and twelve times normal.

Claim 4

Electrolyser according to claim 2, wherein said electrolyte also comprises zinc solution in the form of a zincate.

Claim 5

Electrolyser according to claim 1, wherein said separator is made of a potassium titanate felt and a binding agent.

Claim 6

The electrolyser of claim 4 wherein said binding agent is polytetrafluoroethylene.

Claim 7

Electrolyser according to claim 1, wherein said porous conductive material impregnated with nickel hydroxide has a porosity lying between 65 and 80%.

Claim 8

Method of preparation of the anode of an electrolyser, the method comprising the successive steps of: Coating an expanded metal conductor with a nickel and water paste powder including a binder; Drying the paste; Sintering the conductor at a temperature lying between 900° and 1000° C. which is maintained for 10 minutes to 1 hour in a reducing atmosphere; and Impregnating the textured electrode with nickel hydroxide in a proportion by weight of nickel hydroxide to nickel of between 50 and 75% until the porosity thereof is between 65 and 80%, said impregnation being performed by evolving hydrogen at the electrode in an electrolytic bath containing nickel nitrate and an alcohol or sodium nitrite, as a reducing agent.

Claim 9

Method of preparation of the anode of an electrolyser, the method comprising the successive steps of: Coating an expanded metal conductor with a nickel and water paste powder including a binder; Drying the paste; Sintering the conductor at a temperature lying between 900° and 1000° C. which is maintained for 10 minutes to 1 hour in a reducing atmosphere; and Impregnating the textured electrode with nickel hydroxide in a proportion by weight of nickel hydroxide to nickel of between 50 and 75% until the porosity thereof is between 65 and 80%, said impregnation being performed by evolving hydrogen at the electrode in an electrolytic bath containing nickel nitrate and an alcohol or sodium nitrite, as a reducing agent.

Claim 10

Method according to claim 7, wherein said nickel powder has a particle size of the order of 5 microns.

Claim 11

Method according to claim 8 wherein said nickel powder is obtained by thermal cracking of nickel tetracarbonyl.