Patent GB-1131363-A (GB)
Title: Alkali metal chlorine electrolytic cell
IPC: C25B9/00
Filed: 1965-11-11
Abstract: 1,131,363. Alkali metal chlorine electrolytic cell. PPG INDUSTRIES Inc. Nov. 11, 1965 [Nov. 12, 1964], No.47838/65. Heading C7B. An alkali metal chlorine box-like cell assembly, e. g. for electrolyzing NaCl or KCl comprises a flat horizontal anode 17, Fig. 4 above a flowing mercury cathode in a tray 9 and, below this, a similar anode 10 above a flowing mercury cathode in a tray 11. The cell assembly is constructed from (i) a top from which the anode 17 is suspended, (ii) a bottom which provides the lower tray 11, and (iii) an intermediate unit positioned between the top and bottom, the unit providing the upper tray 9 and suspending the lower anode 10. More than one intermediate unit may be provided. The anodes are of Pt, Au, Ag, Pd, Rh, Ir or Ru plated on Ti or on Ta and are suspended by rods 13, Fig.4, of Cu or Al sheathed with Ti or by Ti lugs (82) and Ti plates (81), Fig.10 (not shown). The lower anode 10 is electrically connected with the mercury cathode in the upper tray 9 thus forming a bi-polar arrangement. Mercury is fed in parallel to each tray 9 and 11 separately by reservoirs or distributers 27 and 29 and the levels of the trays are adjusted such that the mercury flows across them to amalgam sumps 30, 31. Brine is fed to the top tray and overflows through a down-comer (49) Fig. 3 (not shown) into the lower tray, the arrangement being such that the brine flow is transverse to the mercury flow Fig. 2 (not shown). The down-comer (49) also allows Cl 2  produced in the lower part of the apparatus to pass to the upper part. Fig.1 shows the cell assembly with its top 1, bottom 8 and intermediate unit 7 and electrical bus connections 2 and 3 Fig.1 also shows recycling of mercury to the cell assembly from a denuder 37 also illustrated in Fig. 9 (not shown) and means for electrically splitting the flow of mercury at 15 and of amalgam at 35 so as to break electrical continuity. By means of splitter 15 (also illustrated in Fig. 6 not shown, and also described in Specification 1,131, 365) the mercury stream is also divided into portions for each tray of the cell assembly. The stream is fed into a member 20 which rotates about a vertical axis and delivers the mercury through a nozzle 21 into two separate electrically insulated reservoirs 23 and 24 which separately feed the trays 9 and 11. Figs.4 and 5 show details of a mercury reservoir or distributer 29 (also described in Specification 1,131,364). Mercury supplied through the pipe 26 passes through a cavity 72, then upwardly through a slotted channel 71, or a plurality of drilled holes to a cavity 70 from whence it passes through a slot 50 into the tray 11. Figs. 7 and 8 (not shown) illustrate details of amalgam splitter 35 having wheels (96) which either operate on the water wheel principle or are motor driven. Fig. 12 shows a further embodiment of the amalgam splitter 35 (also described in Specification 1,131,366) where amalgam is fed to pipes 114, 115 and over wheels 108, 109 to sumps 106, 107 electrically insulated from one another and thence through outlets 112, 113. Brine is supplied to the cell at 5, Fig.1. The tray levels can be adjusted by screws 55. Cl 2  is removed at 4. Depleted NaCl is removed at 42 and may be resaturated and used again.