Effects of Preheating Temperature and Time of Hongge Vanadium Titanomagnetite Pellet on Its Gas-Based Direct Reduction Behavior with Simulated Shaft Furnace Gases

Li, Wei; Wang, Nan; Fu, Guiqin; Chu, Mansheng; Zhu, Miaoyong

doi:10.2355/isijinternational.isijint-2017-486

Cited by 6 publications

(2 citation statements)

References 34 publications

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“…The world's VTM resources are primarily found in China, Canada, Australia, Russia, New Zealand, and South Africa, totaling a global reserve of almost 48 billion tons [3][4][5][6]. China has reserves of 9.38 billion tons of VTM resources, primarily located in the Panxi region, with the most substantial reserves of 3.6 billion tons found in the Hongge reserves in the Panzhihua-Xichang region [7][8][9][10]. V and Ti mainly exist in VTM as associated ores.…”

Section: Introductionmentioning

confidence: 99%

Impact of Vanadium–Titanium–Magnetite Mining Activities on Endophytic Bacterial Communities and Functions in the Root Systems of Local Plants

Xiong,

Zhang,

Chen

et al. 2024

Genes

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This study utilized 16S rRNA high-throughput sequencing technology to analyze the community structure and function of endophytic bacteria within the roots of three plant species in the vanadium–titanium–magnetite (VTM) mining area. The findings indicated that mining activities of VTM led to a notable decrease in both the biodiversity and abundance of endophytic bacteria within the root systems of Eleusine indica and Carex (p < 0.05). Significant reductions were observed in the populations of Nocardioides, concurrently with substantial increments in the populations of Pseudomonas (p < 0.05), indicating that Pseudomonas has a strong adaptability to this environmental stress. In addition, β diversity analysis revealed divergence in the endophytic bacterial communities within the roots of E. indica and Carex from the VTM mining area, which had diverged to adapt to the environmental stress caused by mining activity. Functional enrichment analysis revealed that VTM mining led to an increase in polymyxin resistance, nicotinate degradation I, and glucose degradation (oxidative) (p < 0.05). Interestingly, we found that VTM mining did not notably alter the endophytic bacterial communities or functions in the root systems of Dodonaea viscosa, indicating that this plant can adapt well to environmental stress. This study represents the primary investigation into the influence of VTM mining activities on endophytic bacterial communities and the functions of nearby plant roots, providing further insight into the impact of VTM mining activities on the ecological environment.

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Section: Introductionmentioning

confidence: 99%

Impact of Vanadium–Titanium–Magnetite Mining Activities on Endophytic Bacterial Communities and Functions in the Root Systems of Local Plants

Xiong,

Zhang,

Chen

et al. 2024

Genes

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“…However, when compared to the relatively comprehensive knowledge of DR characteristics of the conventional iron ores in CO, methane or syngas, the reduction behaviour of titanomagnetite ironsand pellets in H2 gas has not been fully investigated. While the presence of Ti is reported to affect the reduction process of the titanomagnetite ore [29], this effect is not fully understood. Moreover, the influence of Ti on the reaction pathway and phase evolution which occurs during reduction has also not been studied in detail.…”

Section: Background Of the Studymentioning

confidence: 99%

Reduction of New Zealand Titanomagnetite Ironsand pellets in H2 Gas at High Temperatures

Zhang¹

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To reduce the emission of carbon dioxide (CO2) from industrial ironmaking in New Zealand (NZ), it is proposed to perform direct reduction (DR) of NZ titanomagnetite ironsand pellets using H2 gas. In this thesis, the H2 reduction behaviour of pellets made from the NZ ironsand are examined. The aim of the thesis is to understand the reduction mechanism, and develop an analytical kinetic model to describe the reduction progress with time. This has been addressed through a series of reduction experiments in H2 gas. The overall reduction kinetics are examined in a Thermogravimetric analysis system (TGA); the phase evolution during reduction is measured by an in-situ neutron diffraction (ND) method; and the evolution of pellet- and particle-scale morphologies are analysed by scanning electron microscopy (SEM) of quenched samples. Based on the analysis of results from these experiments, the mechanism of the reduction is found to be adequately described by a single interface shrinking core model (SCM). Two different types of pellet are considered in this work: Ar-sintered pellets were sintered in an inert atmosphere to produce pellets containing mainly titanomagnetite (TTM). Pre-oxidised pellets were sintered in air to produce pellets containing mainly titanohematite (TTH). The reduction rate of both types of pellets is found to increase with reduction temperature, H2 gas flow rate, and H2 gas concentration. Above 1143 K, it is found that both types of pellets present a similar reduction rate, while below 1143 K, the reduction of pre-oxidised pellets is much faster than that of Ar-sintered pellets. For both pellets, the maximum reduction degree can reach ~97%. After complete reduction, metallic Fe coexists with other unreduced Fe-Ti-O phases (FeTiO3, TiO2 or pseudobrookite (PSB)/ferro-PSB), which is consistent with the observed reduction degree of < 100%. During reduction of both types of pellets, any TTH present is rapidly reduced first. After this step, TTM is then reduced to FeO, with Ti becoming enriched in the remaining unreduced TTM. FeO is further reduced to metallic Fe, which makes up to ~90% reduction degree. Eventually Ti-enrichment of the TTM leads to a change in the reduction pathway and it instead directly converts to metallic Fe and FeTiO3. Above ~90% reduction degree, reduction of the remaining Fe-Ti-O phases occurs (leading to the formation of TiO2 or PSB/ferro-PSB). The enrichment of Ti in TTM which accompanies the generation of FeO is substantially different from conventional non-titaniferous ores. This enrichment is confirmed by EDS-maps of the particles and stoichiometric calculations of the molar fraction Ti within the TTM phase. This enrichment effect changes the morphology of FeO in the particles, leading to the formation of FeO channels surrounded by Ti-enriched TTM. At the pellet-scale, both types of pellets present a single interface shrinking core phenomenon at higher temperatures. Metallic Fe is generated from pellet surface with a reaction interface moving inwards. However, at lower temperatures this pellet-scale interface becomes less defined in the pellets. Instead, particle-scale reaction fronts are observed. A single interface shrinking core model (SCM) is shown to successfully describe the reduction of pellets for reduction degrees < ~90% at all temperatures studied. However, at reduction degrees > ~90% this model fails. This is attributed to the change in reaction mechanism required to reduce the residual Fe-Ti-O phases that remain dispersed throughout the whole pellet at this stage of the reaction. The single interface SCM indicates that the reduction rate of the Ar-sintered pellets is controlled by the interfacial chemical reaction rate. However, two different temperature regimes are identified. Above 1193 K, the activation energy is calculated to be 41 ± 1 kJ/mol, but below 1193 K the calculated activation energy increases to 89 ± 5 kJ/mol. This change in activation energy appears to be associated with the change of the rate-limiting reaction from FeO → metallic Fe to TTM → FeO. By contrast, the pre-oxidised pellets exhibit mixed control at 1043 K, where a role is played by both the interfacial chemical reaction rate and the diffusion rate through the outer product layer. However, at temperatures of 1143 K and above, the pre-oxidised pellets also exhibit interfacial chemical reaction control, with a single activation energy of 31 ± 1 kJ/mol, which again seems to be consistent the rate-limiting reaction being FeO → metallic Fe. In summary, the findings in this thesis contribute to understanding of the reduction of NZ ironsand pellets in H2 gas, and establish a kinetic model to describe this process. In the future, this information will be applied to develop a prototype H2-DRI shaft reactor for NZ ironsand pellets.

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Evaluation and synergy of material and energy in the smelting process of ferrochrome pellets in steel belt sintering-submerged arc furnace

Wang

et al. 2019

Energy

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Effects of Preheating Temperature and Time of Hongge Vanadium Titanomagnetite Pellet on Its Gas-Based Direct Reduction Behavior with Simulated Shaft Furnace Gases

Cited by 6 publications

References 34 publications

Impact of Vanadium–Titanium–Magnetite Mining Activities on Endophytic Bacterial Communities and Functions in the Root Systems of Local Plants

Impact of Vanadium–Titanium–Magnetite Mining Activities on Endophytic Bacterial Communities and Functions in the Root Systems of Local Plants

Reduction of New Zealand Titanomagnetite Ironsand pellets in H2 Gas at High Temperatures

Evaluation and synergy of material and energy in the smelting process of ferrochrome pellets in steel belt sintering-submerged arc furnace

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