Pilot Plant Study of the ZESTY Flash Hydrogen Direct Reduction Ironmaking Process

Zero Emission Steel Technology (ZESTY) is a flash hydrogen direct reduction ironmaking process. The technology is based on the concept of counter-current flash reduction of iron ore fines by hydrogen in an indirectly heated reactor. Important aspects of this technology are the use of hydrogen only as a reductant and the direct use of iron ore fines without the sintering or pelletizing steps. This paper focuses on 18 pilot plant trials at the ZESTY pilot plant using a single goethite/hematite ore, enabling a comparative analysis of various operating parameters of that specific ore. The highest level of metallization was found to be 90% for the investigated goethite/hematite ore, whereas the highest metallization level achieved from the entire campaign over a range of ores was 98% [ 1 ]. Increasing temperature from 900 to 1050 °C and H 2 /O reduction ratio from 1.2 to 2 has a positive effect on the level of metallization. The highest level of metallization was achieved from the trials when the particle size (d80) was less than 200 µm. Fayalite formation was observed in the DRI product, and the effect of fayalite formation on the metallization level of DRI is worthy of further investigation.