Rio Tinto: Replace natural gas with hydrogen in alumina refining

The $1.2 million study, funded equally by ARENA and Rio Tinto, 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.
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 improve understanding of and the potential for renewable hydrogen to be used in the alumina refining process. It will also inform the scope of development works required to implement hydrogen fuelled calcination technology at an existing alumina refinery.

As the world‘s largest producer of bauxite and largest exporter of alumina, Australia accounts for 15 per cent of global alumina refining capacity. The process is energy intensive, using high pressure steam to produce heat and process bauxite into alumina. Then alumina can be converted to aluminium through smelting.

In its strategy to support industry in reducing emissions, ARENA has targeted the alumina sector as key to achieving this. Alumina refining accounted for over 14M tonnes of carbon dioxide in Australia in 2019, representing around 24 per cent of the country‘s scope 1 manufacturing emissions.

The Australian government‘s first Low Emissions Technology Statement also 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 $11.3M funding for Alcoa to investigate and deploy an alternative technology using recycled steam for process heat, powered by renewable energy.

Rio Tinto‘s study will explore potential for hydrogen to reduce emissions across the aluminium supply chain and complement Alcoa‘s project, ARENA CEO Darren Miller said.

“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,” Miller said.

“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,” he said.

Rio Tinto accounts for about a third of Australia‘s total alumina production capacity. Its aim is to reach net zero emissions across operations by 2050. Company-wide, it is targeting a 15 per cent reduction in absolute emissions and a 30 per cent 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,” Rio Tinto Aluminium Pacific Operations acting managing director Daniel van der Westhuizen said.

“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,” he said.

Article Source :pacetoday.com.au