GB822665A - Improvements in or relating to electrolytic cells - Google Patents

Abstract

822,665. Mercury-cathode electrolytic cells. MESSNER, E. June 28, 1957 [June 28, 1956], No. 20537/57. Class 41. An electrolytic cell having a mercury cathode comprises a vertical or nearly vertical hollow rotatable shaft 6 on which is mounted a series of horizontal or nearly horizontal substantially circular cathode plates 2 located one above the other, the upper surface of each plate being electrically conductive and the lower surface and upstanding peripheral rims 3 being electrically non-conductive, means, e.g. pipes 5, 11, respectively, for feeding mercury and electrolyte to the upper surfaces, and anodes 9 located over each plate 2. All the cathodes may be connected through the shaft 6, which is of conductive material, to a negative source of electricity and all the anodes through leads 10 to a positive source. Alternatively, each cathode may be electrically connected to the next underlying anode to provide a bipolar arrangement, baffles being employed to lengthen and narrow current paths through the electrolyte. The anodes may be graphite or, where sodium sulphate solution is the electrolyte, of a lead-silver alloy, diaphragms being then interposed between corresponding anodes and cathodes. The pipes 11 lead to an annular distributer 13 having holes 12. A flexible strip 1 made of or lined with a non-conductive material overlies each plate 2 adjacent the pipe 5 to form on each plate 2 a pool of mercury through which each plate 2 passes once per revolution of the shaft 6. Amalgam passes through passages into the shaft 6 where it may be decomposed, and gaseous products pass radially beneath each plate 2 to an enclosing shell 16 up which it passes to an outlet. Spent electrolyte leaves by an overflow on the shell 16. In a modification, the plates 2 are slightly conical, concave upwards, and the shaft 6 is tilted slightly so that one generatrix of each plate 2 is horizontal, the pipes 5 delivering mercury to the plates 2 at this location. The strip 1 may be dispensed with, the conical shape ensuring the formation of a mercury pool. In this modification, the shaft 6 may comprise a .series of superimposed elements each carrying one plate 2, the elements being interconnected by V-shaped spigot and socket joints, which may constitute passages leading to the interior of the shaft 6. In both modifications, the anodes 9 may rotate about the shaft 6 or remain at rest.