Alcoa Corporation has announced a development project with the potential to significantly reduce carbon emissions in the alumina refining process, further enhancing the Alcoa’s sustainability performance across the aluminium value chain.
The Australian Renewable Energy Agency (ARENA) has granted A$11.3 million to Alcoa of Australia to test the use of renewable energy in the Mechanical Vapour Recompression (MVR) process.
Alcoa is currently conducting technical and commercial studies to adapt MVR technology to refining. Electricity sourced from renewable energy would power compressors to turn waste vapour into steam, which would then be used to provide heat to the refinery process.
If feasibility studies are successful, Alcoa plans to install a three-megawatt MVR module with renewable energy by the end of 2023. This would take place at the Wagerup refinery in Western Australia, where the technology will be tested at scale.
“Already, Alcoa is the world’s lowest carbon intensity alumina producer. The application of MVR, if proven successful, would be an important step forward in further reducing greenhouse gas emissions,” Alcoa’s vice president for Continuous Improvement Eugenio Azevedo said.
“Using lower carbon alumina in the smelting process will reduce the overall carbon footprint of the metal, when considering the indirect and direct emissions across bauxite mining, alumina refining and aluminium smelting and casting.”
The renewable energy-powered MVR technology could reduce an alumina refinery’s carbon footprint by 70 per cent. The technology also has the potential to significantly reduce water usage in the refining process by capturing water vapour otherwise lost to the atmosphere.
Alcoa has filed provisional patent applications in Australia for the use of the technology. The patent applications cover a variety of MVR applications in retrofit and greenfield scenarios in refining.
The development project also aligns with Alcoa’s strategic priority to “Advance Sustainably.” Alcoa’s global refining system currently has the industry’s lowest average carbon intensity and is the only company providing a low-carbon alumina brand, EcoSource.
Marketed as part of the Sustana line of products, EcoSource has no more than 0.6 metric tonnes of carbon dioxide equivalents for every tonne of smelter-grade alumina produced, compared to 90 per cent of the industry.