Electrolytic extraction of a metal from its metal compound: estimates of optimal energy requirements and their consequences

Abstract

To ensure the sustainability of a world whose growing population demands more materials, products, and energy, we must closely examine the sustainability of the industries that supply them. Metal-making industries encounter an opportunity space at the extraction stage of a metal life cycle when aiming at making a significant impact in energy efficiency and carbon emission mitigation. We first develop a thermodynamic model that establishes the technical criteria for the most efficient operation of an electrolytic cell for a variety of metals. Second, we explore the rigidity of the operating boundary conditions and their impact on energy consumption. We then proceed to examine the energy and carbon impact of a hypothetical electrolytic ferrochromium operation in the United States. This case study demonstrates that the thermodynamic model can serve as a reference framework through which diverse stakeholders can compare the environmental impact of existing and innovative metal extraction processes in order to make informed decisions about environmental regulation, investments, subsidies, and mineral resource management.