A preliminary investigation of some anodes for use in fluidized-bed electrodeposition of metals

The development of fluidized-bed-electrowinning for Cu and other metals appears to be impeded by the high electrical energy consumption associated with the anodes used in such electrowinning. A search for anodes which consume less energy and are suitable for scale-up is described. Using laboratory-scale cells in which copper was electrowon from strong (25 g/dm exp 3 Cu), acidified (100 g/dm exp 3 H sub 2 SO sub 4 ) sulphate solutions on to fluidized cathodes, the following anodes were tested: fluidized-bed-anodes of catalyst-coated Ti particles, packed-bed anodes of Pb shot and graphite, single and double layers of catalyst-coated Ti mesh, and cloth-covered anodes placed directly in the fluidized cathode. In addition, the possibility of using alternative anode reactions, namely oxidation of sulphur dioxide, ferrous ions or cuprous ions, as well as fluidized-bed electrowinning from a cuprous-ion catholyte, were examined. Except for the fluidized anode and the Pb packed-bed anode, all the above systems yielded energy savings. The investigation was not sufficiently detailed to define which of the above was best, although at 2.0 kW h/kg Cu, electrowinning from cuprous solutions with cuprous oxidation on a graphite packed-bed anode offered an energy consumption better than that of the conventional electrowinning plants. 20 ref.--BA.