Electrowinning of Nonnoble Metals with Simultaneous Hydrogen Evolution at Flow‐Through Porous Electrodes: III. Time Effects

Abstract

The electrowinning of zinc from a recirculating alkaline zincate solution 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 thickness on the concentration‐time relations and coulombic efficiency‐time relations were studied. The experimental results show that the highest recovery rate was obtained at both high flow rates and cell currents. There is, however, a practical limit for increasing both the cell current and the electrolyte flow rate. Reasonable agreement between the model predictions and experimental results was obtained. A case study is presented to show how the model equations are used to predict the relationship between time, cell current, flow rate, and coulombs passed which are required to recover 95% of the zinc content of the electrolyte.