Rio Tinto and ARENA to explore green hydrogen in alumina refining

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The Australian Renewable Energy Agency (ARENA) has offered nearly AU$580,000 (€367,000) to Rio Tinto on behalf of the Australian government to run a feasibility test on the use of green hydrogen during the refining process for alumina.

The mining giant is looking to completely decarbonise this process which typically uses natural gases owing to the high temperatures needed to remove impurities.

This marks a continued trajectory towards sustainability for the Anglo-Australian company following a string of controversies over the past year.

Read more: Juukan Gorge: traditional owners want a say in Rio Tinto's mining operations

Renewable energy sources still lag behind in some carbon-intensive industries owing to them not being particularly suited to operations that run using higher temperatures.

Industries such as steel, cement, iron and chemicals are either inefficient or impossible under these circumstances, which has lead to further development for technologies such as carbon capture to sequester excess carbon.

Tinto's primary objective with this study will be to test the feasibility of displacing natural gas with renewable hydrogen at the Yarwun alumina refinery in Gladstone, Queensland.

The investment by ARENA will be met penny-for-penny by Rio Tinto, coming to a combined total of AU$1.2 million (€759,000).

The study will be split into two primary work packages. The first will simulate the calcination process using a lab-scale reactor at Rio Tinto’s Bundoora Technical Development Centre in Melbourne, Victoria, while the second will operate a 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.

ARENA claims alumina represents a key sector for decarbonisation, particularly in Australia.

It reports that in 2019 alone, alumina refining accounted for over 14 million tonnes of carbon dioxide in Australia - roughly 24% of Australia’s scope 1 manufacturing emissions.

The Australian government has also highlighted the importance of decarbonising the steel and aluminium industries to reduce emissions and stimulate economic growth.

Read more: Making net-zero possible

Green hydrogen is also considered an essential technology in shaping the goals to net-zero. It is usually generated through electrolysis generated by offshore wind.

ARENA's CEO Dan 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.

"Exploring these new clean energy technologies and methods is a crucial step towards producing green aluminium.

“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.”

“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," he added.

Tinto is not the first mining giant to explore green hydrogen as a method for decarbonisation.

Anglo American teamed up with ENGIE to run a feasibility study to develop a "green hydrogen valley" in a Platinum-rich part of South Africa.

Read more: Anglo American and ENGIE explore South African hydrogen valley

The valley is set to stretch for 835 km and will help the miner decarbonise its entire platinum mining division.

The collaboration comes following the launch of the 2020 South African Hydrogen Roadmap, which aims for a higher degree of integration for green hydrogen in its economy to help decarbonise key industrial sectors as well as promoting awareness and trust in the hydrogen economy.

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