1. Process principle

1.1 General laws of electrolysis

In an electrolytic cell (figure 1 ), various reactions explain the removal of metal from the anode when a potential difference is created between two electrodes. This removal occurs atom by atom according to Faraday's laws, which stipulate that :

• the amount of metal removed or deposited is proportional to the amount of current ;

• the quantities of the various metal elements removed or deposited, for the same amount of current, are proportional to their valence-gram....