| Abstrakt: |
Aluminum (Al) production consumes 14 kWh of electricity per kg Al and produces 1.1 billion tonnes of carbon emissions (CO2,eq) annually. The Hall-Heroult process is currently the only industrial process for Al production, producing two tonnes of CO2,eq per tonne Al by carbon anode electrolysis. Electrodes that do not participate in the electrolysis of alumina can reduce the impact of Al production. Transitioning to inert anodes implies redesign of electrolysis cells to optimize energy requirements. We performed a life-cycle analysis to compare the ecological footprint of Hall-Heroult and inert production using GaBi software and the ecoinvent database, complemented with primary data. Results were calculated for two Hall-Heroult and fifteen inert scenarios, varying power between 13.5 kWh and 17 kWh for six different energy mixes: Icelandic hydropower, global mix, natural gas, coal, nuclear, and geothermal. A final "best-case" scenario uses hydropower data as the power source for alumina refinement (shown in electrolysis). The results reveal that the energy mix dominates the impact on the ecological footprint in the earlier refinement and electrolysis stages. However, using inert electrodes in smelters powered with renewable electricity can lower the carbon footprint of aluminum production by over 80%. [ABSTRACT FROM AUTHOR] |
