Imperial Chemical Industries Limited

David A Denton

Peter C Hayfield

John F Cairns

Dennis Humphrey

Patrick A Izzard

John Hubert Entwisle

An electrolytic process in which an aqueous electrolyte is electrolysed in an electrolytic cell which comprises at least one anode and at least one cathode, in which oxygen is evolved at the anode, and which is operated at an anode current density of at least 3kA/m.sup.2, in which the anode comprises a substrate having at least in part an outer surface of tantalum, or of an alloy thereof, at least part of the tantalum or tantalum alloy substrate having a coating of an electrocatalytically-active material. The anode may be a tantalum-clad titanium substrate, and the process may be, for example, an electrogalvanizing or electrotinning process.

Electrolytic process

A cathode for use in an electrolytic cell which comprises a metallic substrate, preferably of nickel alloy, and a coating thereon of a mixture of at least one platinum group metal and at least one platinum group metal oxide, the coating comprising from 2% to 30% by weight of platinum group metal. In the electrolysis of water or an aqueous solution e.g. an alkali metal chloride solution, the cathode has a low hydrogen over-voltage.

Cathode for use in electrolytic cell

A method and apparatus for assessing the flatness of a metal anode (e.g. a foraminous titanium anode) which comprises measuring the capacitance of the electrical capacitor formed by urging towards each other under a predetermined load the working surface of said anode and a rigid plane sheet of an electrically conducting material (e.g. copper) as the other plate of the capacitor with a sheet of dielectric material (e.g. polytetrafluoroethylene) therebetween. The apparatus is preferably provided with a compensating weight device to offset the additional weight of the anode current lead-in rod.

Growing community of inventors

Warrington, United Kingdom

David A Denton