There are no quick and easy answers to significant alumina refinery decarbonisation, according to Australian producer Alumina, but it said various "promising" research and development projects and trials are under way to establish potential technical and commercial viability.
It cites mechanical vapour recompression (MVR) and concentrating solar thermal energy, with two study projects under way and partially funded by the Australian Renewable Energy Agency to increase the use of renewable energy in alumina refining. Alumina owns 40pc of Alcoa World Alumina and Chemicals (AWAC), which last year produced 12.8mn t of alumina and saw third-party bauxite shipments of 6.5mn t. US-based aluminium producer Alcoa owns the other 60pc.
MVR is a potential alternative to produce steam to produce renewable electricity to power compressors and provide refinery process heat. The first deployment is planned for AWAC's Wagerup alumina refinery in Western Australia.
Australia's University of Adelaide is leading a study evaluating energy produced from solar thermal technology to be integrated into the Bayer refining process. It uses mirrors to concentrate a large area of sunlight into a targeted location, producing high temperatures.
More than 80pc of China's alumina refineries were powered by coal in 2020, but growing potential is seen for a switch to natural gas. UK-Australian resources firm Rio Tinto this week said it is studying hydrogen as a substitute for natural gas in its alumina refining.
Alumina also referred to data from the International Aluminium Institute forecasting a rise in recycling, semi production and internal scrap recycling to reduce CO2 emissions in aluminium production.
It said current alumina prices are at a low point in the cycle in US dollar terms and as a percentage of London Metals Exchange aluminium prices. Significant amounts of surplus alumina are being exported to China with abnormally high freight costs reducing import parity pricing. Non-Chinese alumina supply and demand is expected to tighten in 2023-24, Alumina said. Third-party bauxite demand is forecast to continue growing and potentially be oversupplied for a few years from producers such as Australia, Guinea and Indonesia.
