La Metallurgia Italiana – July-August 2026
S. Sabah, A. Rizky Rhamdani, B. Mokhtarani, B. A. Nuraeni, G. Brooks, M.A. Rhamdhani, M. Boot-Handford, S. van Dorp
A recent paper published in La Metallurgia Italiana presents the current status of Calix’s Zesty flash hydrogen direct reduction ironmaking process, including findings from pilot plant testing, thermodynamic modelling of fayalite formation, kinetic studies and future development.
Zesty is being developed to produce direct reduced iron directly from iron ore fines, eliminating the pelletising step. The process uses a vertically oriented reactor with indirect electrical heating, enabling hydrogen to serve solely as a reductant rather than as fuel.
Zesty pilot testing achieved metallisation levels of up to 98%. The paper reports that temperature and hydrogen stoichiometric ratio positively affect metallisation, while increasing particle size decreases metallisation. It also identifies ore porosity as an important factor in reduction and examines strategies to suppress fayalite formation. The kinetic modelling findings are consistent with the pilot plant results. The paper also outlines the development of a 30,000-tonne-per-annum demonstration facility in Western Australia.
