Inert anodes can get GHG emissions out of aluminum production but aren't ready for market

September 26, 2022 | Case Study

Aluminum production has a significant environmental footprint. It involves two major steps: first, the Bayer process in which raw bauxite ore is turned into alumina (Al₂O₃), and second, the Hall-Héroult process that involves smelting alumina to obtain pure aluminum. The Hall-Héroult process consumes more than 60% of the energy used in aluminum production and also releases 1.66 ktCO₂ for every tonne of aluminum produced. The indirect carbon footprint due to electricity (15.37 kWh/kg of Al) adds to aluminum's big footprint. Although renewable energy can significantly reduce the indirect carbon footprint, the direct emissions of greenhouse gases (GHG) tetrafluoromethane (CF₄) and hexafluoroethane (C₂F₆) are still concerning and make up roughly 10% of emissions. Replacing carbon anodes with inert materials can eliminate direct emissions and reduce the frequency of electrode replacement — lowering costs overall.