The Australian Renewable Energy Agency (ARENA) has announced up to AU$579 786 in funding to Rio Tinto Aluminium Ltd (Rio Tinto) to support a feasibility study investigating the potential to partially decarbonize its alumina refining operations using renewable hydrogen at its Yarwun alumina refinery in Gladstone, Queensland (QLD).
Australia is the world’s largest producer of bauxite and the largest exporter of alumina, accounting for 15 percent of global alumina refining capacity. Alumina refining is an energy-intensive process that uses high-pressure steam to produce the heat required to process bauxite into alumina. Alumina can then be converted to aluminium in a smelting process.
ARENA has identified the alumina sector as a key target in its strategy to support the industry in reducing emissions due to the potential size of emissions abatement. In 2019, alumina refining accounted for over 14 million tonnes of carbon dioxide (CO2) in Australia, which represents approximately 24 percent of Australia’s scope 1 manufacturing emissions.
Conventional alumina refining uses air and natural gas to achieve the high temperatures necessary to calcine alumina hydrate. Decarbonising alumina refining will require developing an alternative low emissions pathway to calcine alumina hydrate
Displace fossil gas with renewable hydrogen
Rio Tinto will investigate the technical implications of displacing natural gas with renewable hydrogen at its Yarwun alumina refinery in Gladstone, Queensland (QLD). According to the company, hydrogen’s properties make it well suited to industrial processes like alumina refining.
The AU$1.2 million feasibility study, funded equally by ARENA and Rio Tinto, would inform the viability of a potential demonstration project to validate the findings, and will comprise two distinct work packages:
- Simulating the calcination process using a lab-scale reactor at Rio Tinto’s Bundoora Technical Development Centre in Melbourne, Victoria (VIC).
- Preliminary engineering and design study conducted at Rio Tinto Yarwun to understand the construction and operational requirements of a potential demonstration project at the refinery.
The study will see an improved understanding of the potential for renewable hydrogen to be used in the alumina refining process and the scope of development works required to implement hydrogen-fuelled calcination technology at an existing alumina refinery.
In line with Government policy
The Australian Government’s first Low Emissions Technology Statement highlights the importance of developing a low emissions steel and aluminium industry to help reduce emissions and stimulate economic activity. Innovation in metals refining can improve the competitiveness and emissions intensity of Australia’s steel and aluminium production.
Last month, ARENA announced AU$11.3 million in funding for Alcoa to investigate and deploy an alternative technology that uses recycled steam for process heat powered by renewable energy.
ARENA CEO Darren Miller said Rio Tinto’s study would explore the potential for hydrogen to reduce emissions across the aluminium supply chain and would complement ARENA’s support for Alcoa’s project.
If we can replace fossil fuels with clean hydrogen in the refining process for alumina, this will reduce emissions in the energy and emissions-intensive refining stage of the aluminium supply chain. Exploring these new clean energy technologies and methods is a crucial step towards producing green aluminium. This study will investigate a potential technology that can contribute to the decarbonisation of the Australian alumina industry. If successful, the technical and commercial lessons from Rio Tinto’s study could lead to the implementation of hydrogen calcination technology, not only in Australia but also internationally, Darren Miller said.
Rio Tinto accounts for approximately a third of Australia’s total alumina production capacity. Rio Tinto is aiming to reach net-zero emissions across its operations by 2050. Across the company, it is targeting a 15 percent reduction in absolute emissions and a 30 percent reduction in its emissions intensity by 2030, from a 2018 baseline.
We see the ARENA and Rio Tinto-funded study as a step towards reducing refinery emissions and one that has the potential to play an important part in Rio Tinto’s commitment to decarbonisation. We’re investing in work that needs to be done, not only to decarbonise one of our sites but also to help provide a lower-emissions pathway for Rio Tinto and the global aluminium industry. We recognise we are on a long road towards reducing emissions across our operations and there is clearly more work to be done. But projects such as this are an important part of helping us get there, said Daniel van der Westhuizen, acting Managing Director Rio Tinto Aluminium Pacific Operations.
