GB1258716A - - Google Patents

Abstract

1,258,716. Electrolytic cells. PPG INDUSTRIES Ltd. Jan. 29, 1970 [Jan. 30, 1969, July 9, 1969], No. 4299/70. Heading C7B. An electrolytic cell, for producing alkali metal halate from alkali metal halide (e.g. chlorate from chloride) or Li from fused Li salt, comprises a fluid container with inlet 39 and outlet 40, spaced apart parallel anode 18 and cathode 19 disposed in or forming part of, as in Fig. 3, the container, the anode comprising an impervious plate, such as a base-plate of Ti, Ta or Nb (or steel clad therewith) coated with one or more Pt group metals and/or oxides thereof or another metal e.g. RuO 2 and TiO 2 , or of graphite, magnetite or PbO 2 on a substrate, and the cathode comprising a pervious metal plate 23 having at least portions thereof disposed inclined to the vertical or horizontal, the openings in the pervious plate providing channels which lead buoyant products (e.g. gases or molten Li) formed in the space 33 between the pervious plate and the anode upwardly and away from the anode. The cathode may include an impervious back plate 22, e.g. of ferrous metal coated with plastic or rubber, to define with the pervious plate a space 34 through which the buoyant products can rise. The anode may also comprise a pervious plate Fig. 6 (not shown). An insulating gasket 32, of chloroprene or fluoro carbon resin may separate the electrodes 18, 19 around their periphery. The pervious plate 23 may be perforated or louvered Fig. 7 (not shown), or in the form of rods, screen or expanded metal mesh, e.g. of Fe, Ni or steel. For producing NaClO 3 from NaCl, the product stream from the cell, containing hypochlorite and chlorate, may pass through an external crystallizer to remove a portion of the chlorate, and the mother liquor therefrom may be fortified with NaCl, reheated and returned to the cell. A bipolar cell may be provided having a plurality of electrodes with intermediate alternating impervious anodes and pervious cathodes, Figs. 8 and 9 (not shown).