Rio Tinto has inked a Joint Development Agreement (JDA) with Australian environmental technology company Calix to advance the Zero Emissions Steel Technology (Zesty™) demonstration plant in Western Australia. This initiative could enable the use of Pilbara iron ores in lower-emissions steelmaking.

Rio Tinto will invest more than A$35 million (in-kind and financial) to support the Zesty Green Iron Demonstration Plant, which utilizes electric heating and hydrogen reduction to process lower-grade iron ore. The plant will be built in Kwinana, the site previously planned for Rio Tinto's BioIron™ research facility.

Rio Tinto has paused construction of the BioIron pilot plant, citing the need for additional development to reduce technical risks and optimize its furnace design, though research into BioIron continues.

The partnership grants Rio Tinto a non-exclusive global and perpetual license for the potential commercial use of the Zesty technology.