Overview
There is a strong international push towards the development of Hydrogen DRI processes. This is likely to have a significant impact on Australian iron ores in future iron ore markets. Of particular importance is the presence of gangue minerals in the ores, as these gangue minerals required significant energy to melt in subsequent steel making steps. Currently, DRI is typically produced from low gangue ores (Fe>66 wt.%).
Project Details
Two major options are emerging in dealing with the higher gangue content of future DRIs, namely, (i) mix the DRI/HBI with scrap and melt in standard Electric Arc Furnace (EAF) and (ii) introduce a new melting step using Electric Furnace (EF) technology before feeding such liquid iron into the Basic Oxygen Furnace (BOF). This study will undertake a literature review and document industry and experimental experience with melting low carbon DRIs and cold HBI using electric furnace technology. Further, the study will develop mass and energy balance (including an estimate of the Global Warming Potential (GWP)) for the two scenarios identified above at a range of DRI/Scrap ratios. It will also focus on shaft DRI processes whilst a parallel study will review fluidised beds. Five Australian ore types will be considered, with the industrial advisors advising what ore chemistries to consider. Thermodynamic modelling will be used to evaluate the issues of metal/slag chemistry in the two processes, particularly, as that relates to the behaviour of key elements; phosphorous and sulphur, and the impact of low carbon DRI/HBI on yield.
Identified Pathways
Low-carbon iron exports from Pilbara ores
Outcomes
The techno-economic analysis provided by this project will provide an improved understanding of the challenges and opportunities for large-scale green steel production using Australian, and especially Pilbara, iron ores, whether in Australia or overseas.
A key consideration in these modelling scenarios will be the impact of gangue materials on energy requirements, slag volumes and recyclability of the slag produced, steel yield and chemistry of the steel product. Finally, a preliminary techno-economic study and an assessment of the Value in Use (VIU) for the five identified ore types will be performed as well as identification and evaluation of key technical challenges associated with melting low carbon DRI in electric furnace technology. Each of these outcomes will provide guidance and recommendation for further research.