GB1068991A - Process for the electrolysis of alkali metal salts and electrolytic cell therefor - Google Patents

Abstract

<PICT:1068991/C6-C7/1> In a process for electrolyzing alkali metal salt solutions using a mercury cathode and an anode 26 of titanium plated with platinum, a current density of over 100 Amps/dm2 and an interpole distance of less than 3.5 mm, the resulting foam layer which forms on the surface of the electrolyte is removed therefrom, e.g. by allowing (Fig.5) or by causing, Fig. 6 (not shown) the foam to overflow, or by suction means Fig. 7 (not shown). The foam may be delivered thereby to a gas-liquid separator. The cell shown comprises a circular electrolysis chamber 21; a cathode plate 25 to which mercury is fed via inlet 23; a liquid-gas separating chamber 30 into which the foam and saline water overflows through the V-shaped channels formed by the serrated edge of wall 28, the saline water being discharged therefrom via outlet 29, and chlorine gas via outlet 31; and an amalgam separating chamber 33 into which the mercury flows via the discharging port 32. Overflow of saline solution and foam may be caused by means of a rotary impeller 35 Fig. 6 (not shown) or by means of a multiplicity of jet nozzles extending horizontally at the level of the top of the dividing wall 28. Using high current density the anode surface may be positioned below the surface level of the mercury cathode, short-circuiting not resulting. Suitable anodes are described in Specification 1,068,992.