Cradle-to-Gate Carbon Footprint Assessment of Graphite Cathode for Aluminium Electrolysis Pots

AluminiumAluminium is an essential metal to a number of technologies critical to the energyEnergy transition. Therefore, its production capacity has been continuously growing for decades. And so is the interest in its production carbon footprintCarbon footprint, for both primary and secondary (recycled) materials. CathodeCathode blocks used for primary aluminiumPrimary aluminium smeltingAluminium smelting are carbon-rich fossil-based products that require energyEnergy-intensive processes for their manufacturing, especially for graphitized cathodesGraphitized cathode that are now becoming the new mainstream technology. It is therefore essential to evaluate the graphitized cathodeGraphitized cathode production impact on climateClimate change. In this paper, for the first time, a complete “cradle-to-gate” carbon footprintCarbon footprint assessmentAssessment, using the ISO 14 067 as guidelines, dedicated to the graphitized cathodeGraphitized cathode (G-CA) product is performed, based on Tokai COBEX French manufacturing operationsOperation. The results evidence that the production of calcined petroleum cokePetroleum coke (main raw material), the block baking and graphitization treatments account together for the majority of the 4.1 kgCO2eq./kgG–CA emitted during the graphitized cathodeGraphitized cathode production. Major contributor types during the baking and the graphitization processes are the energyEnergy consumption (natural gas especially, used during baking) and the volatiles released during the heat treatmentsHeat treatment. Finally, a sensitivity analysis is performed by parametrization of the calcined petroleum cokePetroleum coke and the electricity carbon footprintCarbon footprint, showing variations of −20% (low-carbon cokeCoke) to + 101% (hard-coal fired electricity).