Electrical and Electrochemical Behavior of Fluidized Bed Electrodes: I . Potential Transients and Time‐Averaged Values

Abstract

A probe has been used to simultaneously measure the electrolyte and particle potentials within a fluidized bed electrode. The difference between the two signals then yielded the overpotential. Transients of all three potentials were stored by a microcomputer and the data processed to yield potential probability distributions and power spectra. Experiments were performed on beds of copper particles undergoing cathodic deposition from acidified sulfate solution and on beds of zinc‐coated particles undergoing deposition or dissolution of zinc with an alkaline zincate electrolyte. Both low frequency and wide band noise were observed in the potentials of copper particles while the former was much less for zinc‐coated polymer particles. An explanation was offered in terms of the hydrodynamics of the electrode, particularly the presence or absence of rising particle‐free regions (“bubbles”). The distributions of time‐averaged potentials with position in the bed were measured and found to be in qualitative agreement with theory. Preliminary results on a moving bed electrode are reported.