News
16 July 2025Electrification & renewable power
The entire ZESTY process can be renewably powered, including the delivery of high temperature heat required to convert iron ore to metal iron.
Developing the lowest-cost solution for zero emissions iron and steel.
Opportunity & challenges
Between 80% and 85% of the industry’s carbon footprint results from the production of iron from iron ore using coal in blast furnaces. Mitigating these emissions will be critical to ensuring we can simultaneously meet our goals for social, economic and environmental sustainability.
Opportunity & challenges
Green iron and steel solutions should also be compatible with a range of ore types, leveraging existing infrastructure and supply chains, and driving further efficiency gains.
The successful development of green iron and steel production will not only help solve an urgent climate challenge, but also add value to local iron ore exports, future-proof local iron and steel production, and support sustainable global development.
No fossil fuels. No carbon emissions.
ZESTY’s indirect heating enables inefficient combustion to be replaced by precise renewably powered electric heating.
Hydrogen is used to remove oxygen from the iron ore to produce metal iron and water. Hydrogen, however, is not combusted or used as a fuel, and is easily recycled. Through efficient electric heating, the most efficient use possible of hydrogen, and the elimination of additional processing steps, ZESTY aims to deliver the lowest cost decarbonisation solution for green iron and steel.
The entire ZESTY process can be renewably powered, including the delivery of high temperature heat required to convert iron ore to metal iron.
Calix’s unique indirect heating approach ensures that hydrogen is used only as a reductant in the production of green iron and steel. Hydrogen is not combusted or used as a fuel, and unreacted hydrogen is simply recycled.
ZESTY is ideally suited to process small particle sizes, creating multiple beneficiation opportunities for lower grade ores and fine material that may otherwise be discarded as waste. ZESTY’s compatibility with lower grade ores provides a pathway to decarbonise much of the world’s current iron ore supply that is otherwise not suitable for use in electric arc furnaces.
ZESTY removes the requirement for iron ore fines to be pelletised, eliminating process steps and avoiding significant capital and energy costs.
ZESTY delivers a highly simplified process for the processing of iron ore fines and ultra-fines without fluidised beds.
Compatible with intermittent and renewable sources of electricity, ZESTY’s electric heating provides a high degree of temperature control with fast start-up and shut down, and highly flexible production rates. As such, it may provide a versatile load balancing service to the energy grid.
Calix’s modular technology can be simply scaled through duplication, de-risking technology scale up and enabling flexible production volumes.
By enabling efficient electric heating, minimal hydrogen use, and eliminating additional processing steps, ZESTY aims to deliver the lowest cost decarbonisation solution for green iron and steel.
A Front-End Engineering and Design study found that even at demonstration scale, ZESTY can produce near-zero emissions hot briquetted iron (HBI) from low grade iron ore for ~AUD$630–800 per tonne of HBI. This cost is close to the range of existing, carbon-intensive HBI processing costs, before any benefit of emissions reduction is accounted for.
Projects
Through strong global partnerships and collaboration with industry, academia and governments, Calix is accelerating the development and commercialisation of its core platform technology to urgently solve some of humanity’s greatest challenges. We recognise and thank each of our partners for their vital contributions.
Calix is solving global challenges in industrial decarbonisation and sustainability.
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At Calix, sustainability means meeting our own needs without compromising the ability of future generations to meet their own needs. Sustainability sits at the core of Calix’s purpose: solving global challenges in industrial decarbonisation and sustainability. Because Mars is for quitters.
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