Theory and applications of electrochemistry in hydrometallurgy

The applications of electrochemical principles and processes are widespread in hydrometallurgy. Previous chapters have introduced the principles of electrode reactions from both the thermodynamic and kinetic aspects. This chapter will deal more specifically with the theory of electrochemical reaction kinetics and the techniques that are used to study these reactions. The various methods used to investigate the kinetics of reactions at metal and mineral surfaces are outlined together with useful information on electrode fabrication and preparation. The basis for potentiostatic instruments is described and the various potential profiles that can be applied to electrodes are outlined with actual examples of the use of the various methods. Emphasis has been placed on the theory, applications and drawbacks of impedance methods as these are not often considered in terms of the methods used to study hydrometallurgical reactions involving the transfer of charge. Important practical considerations to bear in mind when making such studies have been described. This chapter should provide a useful practical guide to those wishing to make use of electrochemical techniques for the first time.