In order to optimize the current efficiency and power consumption of cobalt electrowinning, the electrical conductivity of the electrolyte needs to be known. Electrical conductivity depends directly on various variables including the chemical composition and acidity of the electrolyte. This study was carried out to determine the electrical conductivity and density of cobalt sulfate electrolyte with varying levels of cobalt and sulfuric acid, measured at different temperatures. The experiment conditions selected in this study simulated the range of modern industrial cobalt electrowinning electrolytes. From the experimental data, models were deduced, correlating temperature, cobalt concentration and sulfuric acid concentration to the electrical conductivity and density of the cobalt sulfate electrolyte. The models were developed using empirical formulas, which allowed for reasonable extrapolation, to produce a tool to study the major trends of the electrical conductivity and density. From these models, suggestions could be made to enhance the electrowinning process via increased current efficiency and decreased power consumption. (C) 2003 Elsevier Science Ltd. All rights reserved.