GB1369000A - Electrowinning of metals and apparatus therefor - Google Patents

Abstract

1369000 Apparatus for electro-winning INTERNATIONAL NICKEL CO OF CANADA Ltd 3 Sept 1971 [4 Sept 1970] 41250/71 Heading C7B In the electro-deposition of non-ferrous metal e.g. copper upon a vertical sheet cathode positioned parallel to an insoluble sheet anode, the anode is so constructed or shrouded that the resistance of the current path through the anode electrolyte and cathode is greater at the bottom of the electrodes than at the top thereof (in spite of the greater resistance of the electrolyte at the top owing to gas bubbles evolved at the anode and rising through the electrolyte), thus permitting use of a higher average current density, without exceeding the cathode current density limit for smooth plating, then would be possible using a uniform unshrouded anode. As shown cells formed in a concrete tank 12 are lined with Pb or PVC 14 and have alternate anodes 20 and cathodes 22 suspended therein, the cells being electrically connected in series. To obtain the greater resistance path via the bottom of the electrodes, the anodes e.g. of Pb-Sn alloy, may be shaped as shown, may be uniformly shaped but have the lower part thereof perforated Fig.3 (not shown) or partially masked with insulating strips Fig.4 (not shown) may be formed throughout of Ti (high electrical resistance) expanded mesh coated with a Pt group metal Fig.5 (not shown) or the end may extend into a U-shaped perforated shrouding diaphragm e.g. of PVC of polyethylene Fig.6 (not shown). A surfactant, e.g. dodecylated oxydibenzene disulphonic acid or Na salt or Na alkyl (carboxy) sulphosuccinate may be present in the bath. Copper may be deposited from a bath also containing Ni, Fe and As.