Search Results (7)

Iron smelting is one of the primary sources of carbon emissions. The development of low-carbon ironmaking technologies is essential for the iron and steel industry to realize the “dual carbon” ambition. Hydrogen-based flash ironmaking technology eliminates traditional pretreatment steps such as sintering, pelletizing, and coking while using hydrogen as a reducing agent, significantly reducing carbon emissions. In the present work, a computational fluid dynamics approach is employed to conduct an in-depth analysis of the radiative properties inside the reaction shaft of a flash smelting furnace. The results illustrate that the lowest gas absorption coefficient and volumetric absorption radiation along the radial direction appear at y = 2.84 m, with the values of 0.085 m⁻¹ and 89,364.6 W/m³, respectively, whereas the largest values for these two variables in the axial direction can be obtained at h = 6.14 m with values of 0.128 m⁻¹ and 132,841.11 W/m³. The reduced incident radiation intensity under case 1’s condition led to distinct differences in the radiative temperature compared to the other four cases. The spatial distributions of the particle absorption and scattering coefficients exhibit excellent consistency. The thermal conductivities of all investigated cases depict similar trends along both the axial and radial directions. Volumetric emissive radiation presents a non-linear trend of first increasing and then decreasing, followed by the rise as the height decreases. This study highlights the critical role of hydrogen-based flash ironmaking technology in reducing carbon emissions and provides valuable insights into the radiative characteristics of its reaction shaft under different operating conditions. Full article

This paper reports studies on the thermal chemistry of the flash pyrolysis (heating rate of 20,000 °C/s up to 800 °C) of non-fossil fuel carbon (NFF-C) waste (or refuse-derived fuel, RDF) in the context of using this as an alternative reductant for blast furnace ironmaking. Gas chromatography–mass spectrometry (GCMS) analysis linked to the pyrolyser was used to simulate the thermal processes that take place during injection in the blast furnace raceway, where material experiences extreme temperature (ca. 1000 °C) over very short residence times (<300 ms). Species identification and qualitative analysis of evolved species generated are reported. Whilst the pyrolyser uses flash heating of a static sample, a drop tube furnace was also employed to study a sample moving rapidly through a pre-heated furnace held at 1000 °C to enable reductant burnout rates to be measured. The overarching aim of this piece of work is to study the suitability of replacing fossil fuel with non-recyclable plastic and paper as blast furnace reductants. Full article

The development of a novel ironmaking technology based on fine iron ore concentrate in a flash reactor is summarized. The design of potential industrial reactors for flash ironmaking based on the computational fluid dynamics technique is described. Overall, this simulation work has shown that the size of the reactor used in the novel flash ironmaking technology (FIT) can be quite reasonable vis-à-vis the blast furnaces. A flash reactor of 12 m diameter and 35 m height with a single burner operating at atmospheric pressure would produce 1.0 million tons of iron per year. The height can be further reduced by either using multiple burners, preheating the feed gas, or both. The computational fluid dynamics (CFD)-based design of potential industrial reactors for flash ironmaking pointed to a number of features that should be incorporated. The flow field should be designed in such a way that a larger portion of the reactor is used for the reduction reaction but at the same time excessive collision of particles with the wall must be avoided. Further, a large diameter-to-height ratio that still allows a high reduction degree should be used from the viewpoint of decreased heat loss. This may require the incorporation of multiple burners and solid feeding ports. Full article

This Special Issue on “Process Modeling in Pyrometallurgical Engineering” consists of 39 articles, including two review papers, and covers a wide range of topics related to process development and analysis based on modeling in ironmaking, steelmaking, flash smelting, casting, rolling operations, etc [...] Full article

Despite the dominance of the blast furnace ironmaking process, more attention is being paid to the new technologies with lower energy consumption and carbon dioxide emissions. A novel flash ironmaking technology using pulverized coals and iron concentrates as raw materials, which is different from flash ironmaking with the reductive gas as the reducing agent, is studied. In order to obtain the flow patterns, temperature, and gas composition distribution, as well as particle trajectories in the reaction shaft of the flash ironmaking furnace, the Euler–Lagrangian model with a custom user defined function (UDF) code is used to simulate the processes of the fluid flow, heat and mass transfer, and chemical reactions, including the combustion reaction of pulverized coals and reduction reaction of iron concentrates. The results indicate that the flow patterns, temperature, and gas composition distributions present symmetrical distribution characteristics. The central oxygen expands rapidly after entering the reaction shaft and its distribution is approximately bell-shaped. The temperature distribution in the reaction shaft is wing-shaped. The maximum temperature, 2615 K, is reached at 5 m below the roof of the reaction shaft. The O₂ is quickly consumed after entering the reaction shaft. At 6 m below the roof of the reaction shaft, the oxygen concentration becomes almost zero, with the CO concentration reaching the highest. The Fe₂O₃ and FeO in the iron concentrates are mostly reduced to Fe at 9 m below the roof of the reaction shaft, and more than 95 wt% iron particles could be obtained within 1.2–7.7 s. Full article

The issues of energy consumption and CO₂ emissions of major ironmaking processes, including several new technologies, are assessed. These two issues are interconnected in that the production and use of fuels to generate energy add to the total amount of CO₂ emissions and the efforts to sequester or convert CO₂ require energy. The amounts of emissions and energy consumption in alternate ironmaking processes are compared with those for the blast furnace, currently the dominant ironmaking process. Although more than 90% of iron production is currently through the blast furnace, intense efforts are devoted to developing alternative technologies. Recent developments in alternate ironmaking processes, which are largely driven by the needs to decrease CO₂ emissions and energy consumption, are discussed in this article. This discussion will include the description of the recently developed novel flash ironmaking technology. This technology bypasses the cokemaking and pelletization/sintering steps, which are pollution prone and energy intensive, by using iron ore concentrate. This transformational technology renders large energy saving and decreased CO₂ emissions compared with the blast furnace process. Economic analysis indicated that this new technology, when operated using natural gas, would be economically feasible. As a related topic, we will also discuss different methods for computing process energy and total energy requirements in ironmaking. Full article

The carburization of molten iron is close to saturation in the blast furnace process, while that in the flash ironmaking process is uncertain because there is no pressure from solid charge and no carburization reactions occurring between the deadman and hot metal. Some experiments were conducted to reveal the kinetic mechanism of coke dissolving in carbon-iron melts. Reduced iron powder, electrolytic iron as well as chemical pure graphite were used as experiment materials. With high-purity argon injected as the protective gas, the specimens were heated up to 1873 K in a tubular resistance furnace to study the isothermal mechanism. The results show that the composition of the ferrous sample affects the dissolution rate. When the FeO content of the iron-bearing material rises from 0% to 4.76%, the apparent dissolution rate constant, k_t, falls from 7.98 × 10⁻⁶ m/s to 5.48 × 10⁻⁶ m/s. There are some differences amongst the dissolution rate coefficients of different cokes despite interacting with similar carbon-iron melts, with coke 1 of 7.98 × 10⁻⁶ m/s, coke 2 of 5.17 × 10⁻⁶ m/s, and coke 3 of 3.77 × 10⁻⁶ m/s. Besides, this index decreases with the increase of the dissolution time and solely depends on the procedure of the mass transfer. A negative correlation is demonstrated between k_t and the sulfur content in the iron bath as well. The content of silicon dioxide in the coke has a significant influence on k_t. Additionally, the dissolution rate coefficient increases with the increase of the graphitization degree of coke. Full article