Development of the Flash Ironmaking Technology (FIT) for Green Ironmaking with Low Energy Consumption

<span>This article describes the development of a novel ironmaking technology based on flash reduction. The development started with the proof of the kinetic feasibility, considering that a typical flash reactor provides only a few seconds of residence time. This was followed by tests in a laboratory flash reactor and finally a pilot plant operation. The rate equations formulated in this work were developed considering the optimum combination of temperature, residence time, and reducing gas partial pressure to achieve > 95% reduction degree. Experiments in the intermediate-scale laboratory flash reactor indicated that more than 90% reduction degree could be obtained in a few second residence time at temperature as low as 1175 °C. A pilot reactor operating at 1200–1550 °C was installed and run to collect data necessary for scaling up the process. The tests in this large reactor validated the design concept in terms of heat supply and residence time, and identified technical hurdles. This investigation proved the technical feasibility of the flash ironmaking technology. The results of this work will facilitate the design for the industrial flash ironmaking reactor. The novel technology is expected to decrease the energy consumption in ironmaking by up to 44% compared with the average blast furnace process, and will reduce CO₂ emissions by up to 51%. When hydrogen is used, the proposed process would use up to 60% less energy with little carbon dioxide emissions. However, it is noted that the energy requirements and CO₂ emissions during the production of natural gas, hydrogen or coal must be added for a comprehensive comparison.</span>

Direct Reduction Ironmaking by Co-Pyrolysis of Biomass Tar Model Compounds and Iron Ore Fines

The low carbon metallurgy technology based on the high-value utilization of biomass is considered as the key development orientation of green ironmaking. In this paper, a pyrolysis coupling technology of biomass tar and iron ore powder is proposed for the reduction of iron ore. Tar is degraded efficiently due to the synergy effects respectively through oxidation of iron oxides and the catalytic action of reduced iron, and simultaneously the reduction of iron oxide to metallic iron. Representative tar components including vanillin, naphthalene, and catechol were selected as tar model compounds. The various reaction conditions on the reduction degree of iron ores was investigated, which include the type of tar component, the pyrolysis temperature, and the ratio of reactants. According to the results, the optimal relationship between tar degradation and reduction of iron ore was identified. It can be found that under the catalytic effects of iron ore fines, the degradation efficiency of the three model compounds followed the following order: naphthalene > vanillin > catechol. Naphthalene owned the better reduction ability. The highest reduction degree of the product reached to 78.5% at 800 °C for 30 min.