Rio Tinto has signed a joint development agreement with Australian tech firm Calix, investing more than $35 million to build a green iron demonstration plant in Kwinana.
The facility will replace a site previously earmarked for Rio’s own BioIron pilot.
The plant will utilise Calix’s Zesty (Zero Emissions Steel Technology) process, viewed as a critical breakthrough for the sector because it uses electric heating and hydrogen to process lower-grade iron ores, such as those found in the Pilbara, without the need for pelletisation.
“The world needs low-emissions steel if it is going to decarbonise, and we continue to look at a range of ways Pilbara iron ores can help to do this as new technologies emerge,” Rio Tinto iron ore chief executive Matthew Holcz said.
“We’re pleased to partner with Calix, an Australian technology company, to help progress the Zesty technology to be able to use Pilbara iron ores for lower-emissions steel making.”
The mining giant confirmed that its proprietary bioiron technology, which uses biomass rather than coal, requires “additional development” to minimise technical risks and optimise furnace design.
While Rio remains committed to bioiron in the long term, the Kwinana site, south of Perth, will now host Calix. Rio stated the move allows them to support multiple pathways to decarbonisation simultaneously.
The project has secured the backing of Western Australian Premier Roger Cook and holds a $44.9 million grant from the Australian Renewable Energy Agency (ARENA).
“Locally made green iron is a key part of my vision to become a renewable energy powerhouse and make more things here,” Cook said.
“Coupled with my government’s recent announcement that government will take an ‘if not, why not’ approach to green steel procurement on major government projects, the Zesty Green Iron Demonstration Plant will support our efforts to diversify WA’s economy so that it can remain the strongest in the nation.”
Subject to a final investment decision expected in 2026, Rio Tinto will supply 10,000 tonnes of iron ore for the plant’s commissioning. In exchange for its funding and technical support, Rio secures a non-exclusive global license to use and market the Zesty technology.
