Calix has completed a front-end engineering and design (FFED) study for a 30,000 tpy zero emissions steel technology (ZESTY) H₂ direct reduced iron (H-DRI) demonstration plant. The study was supported with funding from the Australian Renewable Energy Agency (ARENA).

The ZESTY FEED study aimed to complete the initial engineering for a 30,000 tpy ZESTY H-DRI demonstration plant and provide an estimate of the levelized cost of producing briquettes of H-DRI using iron ore fines (<6 mm) of low-grade hematite or hematite/goethite blends using the ZESTY technology. The study was supported by an expanded ore testing program at Calix’s Bacchus Marsh pilot scale facility, covering a large proportion of Australian iron ore sources.

The FEED study estimates that HBI production from low-grade iron ore can be produced for a price of ~$410/t–$520/t iron using the ZESTY technology at demonstration scale. This value includes the capital cost of the plant and the processing cost. It does not include the cost of land or the cost of transport of the input and output materials.

The estimated cost of HBI production by ZESTY at demonstration scale is close to the range of existing conventional HBI processing costs. This is despite the use of H₂ as a reductant, and does not take credit for any carbon price, carbon border adjustment mechanism, or other green premium that a near zero emissions iron product may attract. A near zero emissions ZESTY HBI product would enable between 80% to near 100% total reduction in carbon emissions from the final steel product, depending on the processing route used.

ZESTY’s potential to achieve a cost of production close to the range of conventional HBI production even at small (demonstration) scale is a result of its minimal use of H₂, the relative simplicity and efficiency of the electrically heated process, and the elimination of the agglomeration and induration process steps. The total energy requirement of the process is projected to be 4.2 MWhr/t–4.6MWhr/t iron, including the requirements to produce H₂. The ZESTY plant’s energy requirement excluding H₂ production was projected to be 0.9 MWhr/t–1.3MWhr/t iron.

The overall capital and operating costs are expected to reduce further as the core technology is scaled and refined. The Calix ZESTY process takes advantage of a short residence time while utilizing lightweight materials, resulting in a processing plant that is simple to construct and operate.

Compatible with intermittent and renewable sources of electricity, ZESTY may also be able to provide a versatile grid-load balancing service to the energy grid, due to the technology’s potential to match its energy use to the grid’s requirements across a wide range. Demand side load balancing – analogous and complementary to supply side energy storage – could support further renewable energy integration into the grid, lower grid balancing costs, and potentially enable more economical industrial energy use.