Calculation of Mass Transfer Coefficients in Metal Deposition Using Electrochemical Tracer Techniques

Abstract

A modification of the tracer technique of Ettel et al. has been developed for determining mass‐transfer coefficients in electrolytes for both electrowinning and electrorefining systems. The method involves the direct measurement of the limiting current density of a more noble tracer ion at low concentration by cyclic voltammetry techniques in an electrolyte of choice. A Ag+ tracer in acid copper sulfate is used as the example. Additional tests were made by codepositing the tracer with copper to compare the results of the two methods. The effect of copper ion concentration and temperature on the electrochemical and transport properties of the solution were determined. The results obtained using cyclic voltammetry techniques were found to be in good agreement with those from the standard codeposition determinations. Additional refinement of the technique is needed to more clearly define the limitations of the technique when used for metal deposition evaluations.