Mm. Saleh et al., ELECTROWINNING OF NONNOBLE METALS WITH SIMULTANEOUS HYDROGEN EVOLUTION AT FLOW-THROUGH POROUS-ELECTRODES .3. TIME EFFECTS, Journal of the Electrochemical Society, 144(3), 1997, pp. 922-927
The electrowinning of zinc from a recirculating alkaline zincate solut
ion at a flow-through porous electrode was investigated. Experimental
results were obtained to test the predictions of a mathematical model.
The effects of electrolyte flow rate, cell current, and electrode thi
ckness on the concentration-time relations and coulombic efficiency-ti
me relations were studied. The experimental results show that the high
est recovery rate was obtained at both high flow rates and cell curren
ts. There is, however, a practical Limit for increasing both the cell
current and the electrolyte flow rate. Reasonable agreement between th
e model predictions and experimental results was obtained. A case stud
y is presented to show how the model equations are used to predict the
relationship between time, cell current, flow rate, and coulombs pass
ed which are required to recover 95% of the zinc content of the electr
olyte.