Thermodynamics of electrochemical reduction of alumina

Abstract

This paper presents an updated calculation of the theoretical minimum energy required to electrochemically reduce alumina to aluminum using either consumable carbon anodes or oxygen evolving (non-consumable or inert) anodes. Knowledge of this energy (the standard enthalpy of reaction) is required for heat balance calculations. The reversible potential, or Nernst potential, needed to calculate cell voltage, is obtained from the standard Gibbs energy of reaction and the activities of reactants and products. A more conservative definition of energy efficiency is proposed. Problems involving heat balance and energy consumption when using oxygen-evolving anodes are discussed.