GB1475953A - Method of preparing ammonium and sodium persulphates by electrolysis - Google Patents

Abstract

1475953 Electrolytic cell for preparing persulphates L'AIR LIQUIDE SOC ANON POUR L'ETUDE ET L'EXPLOITATION DES PROCEDES GEORGES CLAUDE 19 June 1975 [24 July 1974] 26192/75 Heading C7B Ammonium or sodium persulphate is prepared by electrolysis of ammonium or sodium bisulphate solution placed between a cathode of Zr or Zrbased alloy and an anode preferably of Pt, with no diaphragm interposed, using pulsating D.C. As shown, a cylindrical anode assembly of Pt covered Cu rods 4 are supported from positive terminal 6 between concentric Zr tube cathodes 2, 3 connected to negative terminal 14. The bisulphate solution electrolyte is supplied through nozzle 16 in supply chamber 15 sealed to the lower end of outer cathode 3 to flow between both cathodes and anode 4 and pass out through similar withdrawal chamber 17 with nozzle 18 sealed to the upper end of cathode 3, whilst pulsating D.C. is supplied from source 7. Refrigerating fluid is supplied through nozzle 13 in upper region of the annular gap 9 between outer cathode 3 and cell casing 10 to flow through the gap 9 then via return tube 8 through an insulating tube 5 held in inner cathode 2, from lower part 5 to upper part 5a. The D.C. supply is rectified A.C., the rectifier being preferably thyristors having control electrodes for adjusting the periodic interruption, e.g. in a half-wave or full-wave rectifying circuit Fig. 2 (not shown). Preferably the current supplied is formed by a train of sine-wave arcs Fig. 3 (not shown).