Isothermal and non-isothermal reduction kinetics of iron ore oxygen carrier by CO: Modelistic and model-free approaches

Dilmaç, Nesibe

doi:10.1016/j.fuel.2021.120707

Cited by 30 publications

(6 citation statements)

References 27 publications

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“…As a kinetic supplementary method, the iso-conversion (model-free) method allows the reaction process to be determined as a function between activation energy and conversion degree without considering the kinetic model . The relationship between activation energy and conversion degree can be obtained by linearly fitting the time and temperature when a specific conversion rate is reached. , The most common model-free method is acquired by taking the natural logarithm of both sides of eq ln nobreak0em0.25em⁡ t α = E normala R T + ln G ( α ) A …”

Section: Methodsmentioning

confidence: 99%

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Fluidized Reduction Kinetics of Boron-Bearing Iron Concentrate by Hydrogen at Low Temperatures Based on Model-Fitting and Model-Free Methods

Li,

Yu,

et al. 2024

ACS Omega

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Pyrometallurgy is the most effective way to comprehensively utilize boron-bearing iron concentrate, and there is an urgency for an environmentally friendly and efficient method to achieve the prereduction of boron-bearing iron concentrate. In this study, the mechanism and kinetics of isothermal hydrogen reduction of boron-bearing iron concentrate in a fluidized bed at 500–570 °C were discussed. The reduction degree was quantified in combination with the online gas composition analysis technique, and the phase and microstructure of the reduced products were characterized. The results exhibited that the apparent activation energy remained constant during the whole reduction process, with average values of 50.67 and 48.08 kJ/mol calculated by the model-free and model-fitting methods, respectively, and the reaction was controlled by the contracting sphere model. The formation of a microporous metallic iron facilitated the rapid penetration of hydrogen to the reaction interface. Therefore, the intrinsic chemical reaction at the interface determined the whole reaction process.

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Section: Methodsmentioning

confidence: 99%

“… 38 The relationship between activation energy and conversion degree can be obtained by linearly fitting the time and temperature when a specific conversion rate is reached. 39 , 40 The most common model-free method is acquired by taking the natural logarithm of both sides of eq 8 …”

Section: Methodsmentioning

confidence: 99%

Fluidized Reduction Kinetics of Boron-Bearing Iron Concentrate by Hydrogen at Low Temperatures Based on Model-Fitting and Model-Free Methods

Li,

Yu,

et al. 2024

ACS Omega

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“…Equation ( 5) is obtained by transforming and integrating Equation (3). In the equation, G(α) is the integral form of the kinetic mechanism function model of the reaction, and the commonly used kinetic mechanism function models [34][35][36] are listed in Table 6. G(α) is linearly fitted to the reaction time t by using the model fitting method, and the G(α) with the best linear correlation is the kinetic mechanism function of the reaction in this study [37][38][39][40] .…”

Section: Kinetics Analysis Methodsmentioning

confidence: 99%

Isothermal Reduction Kinetics of the Mixture of Iron Carbon Agglomerates and Sinter

Bao,

Chu,

Tang

et al. 2024

ISIJ Int.

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The effect of iron carbon agglomerates (ICA) on the reduction of sinter is very important to blast furnace (BF) ironmaking. In this paper, the isothermal reduction kinetics of ICA-sinters mixture and the coupling synergistic mechanism between ICA and sinter are comprehensively studied. The results show that the early stage of isothermal reduction of ICA-sinters mixture is jointly controlled by the interfacial chemical reactions of FeO being reduced to Fe in sinter and gasification reaction in ICA, and the later stage is controlled by the internal diffusion. As the reactivity of ICA improves from 52.81% to 69.71%, the isothermal reduction reaction activation energy of ICA-sinters mixture decreases from 84.22 to 72.58 kJ/mol in early stage and decreases from 110.78 to 97.41 kJ/mol in late stage. Meanwhile, the activation energy of isothermal reduction reaction for the mixture of ICA and sinter with a higher reducibility is lower. There is a coupling synergistic effect between ICA and sinters, and ICA plays a continuous role in circulating CO and transferring oxygen during the reduction of sinter, which can significantly promote the reduction of iron oxides in sinter. The synergistic effect gradually increases with the improvement of the reactivity of ICA and the reducibility of sinter.

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“…Using the model-fitting method, G(α) is linearly fitted to the reaction time t, and the G(α) with the best linear correlation is the mechanism function of the reaction in this study [15,[28][29][30]. Table 10 lists the commonly used kinetic mechanism functions [31][32][33][34]. Meanwhile, the value of reaction rate constant k(T ) at different reaction temperatures can be obtained through the slope of the fitting curve…”

Section: Effect Of the Addition Amount Of Ica On The Isothermal Reduc...mentioning

confidence: 99%

Effect of the addition amount of iron carbon agglomerates on the isothermal reduction kinetics of pellets–iron carbon agglomerates mixture

Bao

Chu

Liu

et al. 2021

Ironmaking & Steelmaking

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The effect of iron carbon agglomerates (ICA) on the reduction of pellet (or sinter) is very important to the smelting efficiency of BF. In this paper, the effect of addition amount of ICA on the reduction of pellets and the isothermal reduction reaction kinetics of pellets-ICA mixture were comprehensively studied. The results show that the addition of ICA among pellets can significantly improve the reduction degree of pellets. There is a synergistic effect between ICA and pellets. All the pellets-ICA mixtures have the same reaction control mechanism: stage 1 is the secondary order chemical reaction F2, and stage 2 is the phase boundary reaction R2 of shrinking core model. As the amount of ICA increases from 15 to 35%, the activation energy of pellets-ICA mixture at stage 1 decreases from 95.53 to 75.21 kJ/mol, and the activation energy at stage 2 increases from 98.18 to 138.34 kJ/mol.

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Isothermal and non-isothermal reduction kinetics of iron ore oxygen carrier by CO: Modelistic and model-free approaches

Cited by 30 publications

References 27 publications

Fluidized Reduction Kinetics of Boron-Bearing Iron Concentrate by Hydrogen at Low Temperatures Based on Model-Fitting and Model-Free Methods

Fluidized Reduction Kinetics of Boron-Bearing Iron Concentrate by Hydrogen at Low Temperatures Based on Model-Fitting and Model-Free Methods

Isothermal Reduction Kinetics of the Mixture of Iron Carbon Agglomerates and Sinter

Effect of the addition amount of iron carbon agglomerates on the isothermal reduction kinetics of pellets–iron carbon agglomerates mixture

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