During the electrolysis process, aluminium is deposited at the cathode and oxygen is liberated at the anode. Some of this oxygen reacts with the carbon in the graphite to form carbon-dioxide, thus slowly burning away the anodes. Thus, the anodes have to replaced periodically.
Explanation: During the electrolysis process, aluminum is deposited at the cathode, and oxygen is liberated at the anode. Some of this oxygen reacts with the carbon in the graphite to form carbon dioxide, thus slowly burning away the anodes. Thus, the anodes have to replaced periodically.
