Name of the Project
Zesty green iron demonstration plant.

Location
Kwinana, south of Perth, in Western Australia.

Project Owner/s
Multinational mining company Rio Tinto and Australian environmental technology company Calix.

Project Description
Zero Emissions Steel Technology (Zesty) is being positioned as a pathway for using Pilbara iron-ore in lower-emissions steelmaking.

The proposed plant is designed to produce up to 30 000 t/y of hydrogen direct reduced iron or hot-briquetted iron (HBI) from various iron-ore feedstocks.

The facility is intended to operate as an open-access toll-processing plant, enabling industry participants to convert ore into hydrogen direct reduction iron or HBI.

The Zesty process is compatible with lower-grade iron-ore and uses electric heating and hydrogen reduction to produce reduced-emissions iron. If approved, the demonstration plant will be built at a site previously earmarked for Rio Tinto’s BioIron research and development facility and its associated pilot plant.  

Subject to a final investment decision (FID) and successful project construction, Rio Tinto will supply up to 10 000 t of a range of Pilbara iron-ores for use in plant commissioning and the initial testing phase of the project. The company also intends to facilitate engagement with potential downstream users of the Zesty product.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
Not disclosed.

Capital Expenditure
Rio Tinto will invest more than A$35-million, subject to project milestones, comprising in-kind and financial contributions, to assist Calix with the Zesty plant. The project is also supported by a grant of up to A$44.9-million from the Australian Renewable Energy Agency, subject to matched funding being secured.

Planned Start/End Date
The demonstration project has entered its detailed design engineering phase to help inform an FID, expected in 2026.

Latest Developments
Rio Tinto signed a joint development agreement with Calix in November 2025 to support construction of the Zesty demonstration plant.

Key Contracts, Suppliers and Consultants
None disclosed.

Contact Details for Project Information
Rio Tinto, email media.enquiries@riotinto.com.