Synthesis of metal salts via anodic dissolution

The cells are operated on a batch basis cuprous oxide falls from the anodes to the bottom of the tanks. At suitable intervals, the electrolysis is stopped, the residual electrodes removed for remelting, and the Cu20-NaCl slurry is agitated and pumped out of the cell for external separation of CU2O. 

There is a growing awareness that electrochemical methods of synthesis may be used to achieve controlled purity compounds which are difficult to produce by chemical or thermal methods. A general strategy for the synthesis of metal salts or complexes is controlled anodic dissolution of the pure metal in a suitable electrolyte. In a simple case, the anode process may be the formation of a soluble, hydrated metal ion (as in electrorefining, section 4.3)  

In the potassium stannate process shown schematically in Fig. 5.16 the anode is a steel basket filled with solid tin bars or pellets immersed in KOH solution. Under suitable conditions, the tin dissolves as stannite  

The anolyte is sparged with air, which instantaneously oxidizes stannite to stannate  

The KOH effectively formed in the catholyte is metered back to the anolyte. 

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