Electrochemical principles also find applications in metallurgical process. The reduction of oxides of active metals such as sodium, potassium etc., by carbon is thermodynamically not feasible. Such metals are extracted from their ores by using electrochemical methods. In this technique, the metal salts are taken in a fused form or in solution form. The metal ion present can be reduced by treating it with some suitable reducing agent or by electrolysis. Gibbs free energy change for the electrolysis process is given by the following expression
∆G° = -nFE°
Where n is number of electrons involved in the reduction process, F is the Faraday and E° is the electrode potential of the redox couple. If E° is positive then the ∆G is negative and the reduction is spontaneous and hence a redox reaction is planned in such a way that the e.m.f of the net redox reaction is positive. When a more reactive metal is added to the solution containing the relatively less reactive metal ions, the more reactive metal will go into the solution.
For example,
Cu (s) + 2Ag+(s) → Cu2+(aq) + 2Ag (s)
Cu2+(aq) + Zn (s) → Cu (s) + Zn+(aq)
