The density and electrical conductivity of nickel sulfate electrolytes as a function of nickel and sulfuric acid concentration and electrolyte temperature have been experimentally measured. Models have been developed to explain the effects of temperature, nickel and sulfuric acid concentration on the electrical conductivity and density. Empirical equations to mathematically quantify the reported values have also been derived to allow reasonable extrapolation. These models maybe used to enhance the electrorefining and electrowinning processes.