A major economic and operational drawback of the Hall-Heroult process is the continuous consumption — Metallurgy and Isolation of Elements Chemistry Question

💡 Solution & Explanation

During the electrolysis, oxygen ions ($O^{2-}$) migrate to the anode and are discharged as oxygen gas. At the high operating temperatures ($\sim 900^\circ C$), this liberated oxygen aggressively attacks the solid carbon (graphite) anodes, burning them away as $CO$ and $CO_2$ gases.