Mining giant Rio Tinto (ASX:RIO) has completed due diligence for Calix’s (ASX:CXL) Zesty Green Iron Demonstration Project in Western Australia.
The due diligence completion clears the way for the first cash contribution of $3 million to the project from Rio Tinto.
In mid-November 2025, both companies executed a joint development agreement, with Rio Tinto funding over $35 million of cash and in-kind support for the demonstration of the Zesty technology.
Zesty is designed to produce up to 30,000 tonnes per year of hydrogen direct reduced iron or hot briquetted iron from a range of iron ore sources.
A final investment decision is expected to be reached in 2026. Subject to a FID and construction of the plant, Rio Tinto will provide up to 10,000 tonnes of a range of Pilbara iron ores for use in plant commissioning and operations, alongside introductions to potential users of the Zesty green iron product for material testing and downstream processing to steel.
The Zesty technology uses a combination of electrical heating and hydrogen reduction to produce green iron and green steel. Zesty aims to provide lowest cost pathways to green iron and steel through minimal hydrogen consumption, flexible electric heating compatible with intermittent renewable energy sources, elimination of ore pelletisation, and enabling the use of fines and lower grade iron ores.
Rio Tinto operates in 35 countries, where more than 60,000 employees are working to provide materials the world needs. The company’s portfolio includes iron ore, copper, aluminium, and a range of other minerals and materials needed.
Calix is a technology-focused company that aims to solve global challenges in industrial decarbonisation and sustainability.
Write to Aaliyah Rogan at Mining.com.au
Images: Calix
