GB1151654A - Electrolytic Cells - Google Patents

Abstract

1,151,654. Fused electrolyte cell; powder metallurgy. E.I. DU PONT DE NEMOURS & CO. April 7, 1967 [April 8, 1966], No. 16045/67. Headings C7B and C7D. A fused electrolyte cell e.g. a "Downs" cell for producing Na and Cl comprises at least one insulating spacer body positioned within the fused salt electrolyte e.g. of Na Cl to locate the conductive diaphragm between the anode and cathode and prevent physical contact therewith, the body comprising a core of AlN e.g. 20-85%, Si 3 N 4 e.g. 5-70% and/or Si e.g. 10-40%, and an insulating skin inert towards the electrolyte. The body may be formed by powder metallurgy using powdered materials of particle size less than 150 microns. The skin may be of the same composition as and homogeneous with the core, e.g. of A1N and/or Si 3 N 4 , or of alumino-silicate (reaction product of sintered Al 2 O 3 +SiO 2 ). The core may be formed by reacting e.g. at 700-1700‹C. a pressurecompacted e.g. at 5000-60000 p.s.i. mixture comprising finely divided Al and Si 3 N 4 so that the core contains at least 20% A1N formed in situ; the body composition may thus also contain dispersed Al or Al-Si alloy and the skin made insulating by nitriding e.g. at 900-1700‹C. in N 2 or cracked NH 3 . A single ring-shaped spacer body may be affixed to one of the electrodes opposite the bottom of the diaphragm. Preferably as shown, a plurality of spacer bodies e.g. disc rollers 6 are fixedly attached e.g. by brackets 7 around the bottom of a cylindrical perforate steel diaphragm 1 to facilitate its insertion into and withdrawal from the annular space between the vertical cylindrical inner graphite anode 13 and outer steel cathode 12.