Kinetic study and modelling of silver dissolution in synthetic industrial silver electrolyte as a function of electrolyte composition and temperature

The kinetics of silver dissolution in silver electrorefining process was investigated using a series of synthetic electrolytes and different electrode sizes. Kinetic models at corrosion potential and industrial range overpotentials were constructed as a function of electrolyte composition and temperature. The results revealed that overpotential of 150-200 mV vs. corrosion potential represented the values corresponding to the industrial silver electrolysis. In order to achieve a high current efficiency in silver electrorefining, our kinetic models suggest that concentration of HNO3 should be less than 5 g/dm3 or 3 g/dm3 for operation at 25 °C and 45 °C, respectively.