Gaseous reduction of iron oxides: Part IV. mathematical analysis of partial internal reduction-diffusion control

Tien, R. H.; Turkdogan, E. T.

doi:10.1007/bf02643212

Cited by 62 publications

(25 citation statements)

References 9 publications

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“…Weiss et al 8) investigated the reduction process of hematite to magnetite and found that the system gradually forms a micro-porous layer of magnetite while the porosity initially increases and then decreases. Turkdogan et al [9][10][11][12] explored the gaseous reduction of iron oxides in H 2 or CO-CO 2 mixtures and discussed the rate-controlling step of reduction process. However, the comparison of reduction behavior of hematite and CF at same test conditions remains poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Isothermal Reduction Kinetics of Powdered Hematite and Calcium Ferrite with CO–N<sub>2</sub> Gas Mixtures

Ding

Xuan

et al. 2016

ISIJ Int.

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CF is regarded as the best bonding phase with superior strength and reducibility in sintering. The comparison of hematite and CF reduction process was made in this study. Isothermal reduction experiments of powdered hematite and CF in a continuous stream of 30% CO and 70% N 2 at 1 123 K, 1 173 K and 1 223 K were conducted through thermo-gravimetric analysis (TGA). Reduction rate analysis revealed that the reduction of hematite comprises three independent steps (H→M→W→I), whereas that of CF mainly comprises two steps (H→M→I). The reduction of powdered hematite and CF can be described by shrinking layer model, not shrinking core model completely. Results of the ln-ln and Sharp analysis methods indicated that the reduction of hematite included two kinetics stages, namely, plane-like mechanism and then spherulitic-type mechanism. The reduction of CF only included the plane-like mechanism stage. The model free method revealed that the activation energy of hematite and CF reduction were 5.81 kJ·mol − 1 and 46.89 kJ·mol − 1 , respectively.

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Section: Introductionmentioning

confidence: 99%

Isothermal Reduction Kinetics of Powdered Hematite and Calcium Ferrite with CO–N<sub>2</sub> Gas Mixtures

Ding

Xuan

et al. 2016

ISIJ Int.

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“…Taking R1 for example. The chemical reaction rate of the ore fine with hydrogen is given by Tien 22) and Usui 23) and is expressed as:…”

Section: )mentioning

confidence: 99%

Simulation Study on Performance of Z-path Moving-fluidized Bed for Gaseous Reduction of Iron Ore Fines

2012

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Performance of the Z-path moving-fluidized bed reactor for gaseous reduction of iron ore fines was numerically investigated. The proposed mathematical model was developed by analyzing the gas-solid transport phenomena and chemical reactions in the reactor. The model was solved by a new solving approach -integration of FLUENT package (V6.3) and PHOENICS (V3.3). Numerical simulation results of cold state were compared with the experimental data and the simulation results including pressure drop per perforated plate, gas flow pattern and solid flow pattern agreed well with the experimental ones. The developed CFD model then conducted some hot state predictions of gaseous reduction of iron ore fines using reformed COG gas and purified COREX export gas in this reactor. Results indicate that under hot state, the performance of the reactor depends on the reducing gas supplied. Pressure drop per perforated plate decreases one by one from the bottom plate to the top plate and some improvements are needed for the perforated plate arrangement in the reactor. For ore fines gaseous reduction, the reactor displays a high utilization efficiency of gas sensible heat and gas reduction potential. The Z-path moving fluidized bed has the advantage that it realizes a gradient utilization of heat and reduction potential of the gas in iron ore fines reduction with a comparatively simple structure. In the cases simulated, the top two plates play a role of preheating the ore fines and the bottom three plates reducing the ore fines. For operation control, the reactor with three inclined perforated plates is reasonable and preheating ore fine may be carried out by other means.

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“…[16][17][18] Rao's group 19,20) have investigated the intrinsic rate of reduction metallic oxides and examined the influence of pore diffusion of gaseous species on the shape of the growing nucleus, and modeled the reduction of hematite with CO 2 and CO gases as the reacting intermediates. Tien and Turkdogan 21) reported a mathematical analysis of gaseous reduction of iron oxides with considering the partial internal reduction of the porous oxide and gas diffusion in the porous iron layer. Szekely and Evans 17) presented a structural model for the reaction of porous oxides, and the model incorporated some structural parameters, such as grain size, porosity.…”

Section: Introductionmentioning

confidence: 99%

A Model for the Reduction of Metal Oxides by Carbon Monoxide

Dang

Chou

2018

ISIJ International

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The reduction of metal oxides by carbon monoxide is a very significant reaction in metallurgical and chemical industries. In current study, a kinetic model describing the reduction reaction of metal oxides by CO has been developed. The model is in the analytic function of parameters such as temperature, radius of the particle, CO content, density of metal oxides and time, which is, therefore, convenient for usage and theoretical analysis. The developed model can be applied to describe the reduction kinetics of metal oxides under both isothermal and non-isothermal conditions. Particularly, it can be used to describe the kinetics of both single reduction reaction (single reaction interface) and dual reduction reactions (double reaction interfaces, such as, the reduction of Fe 2 O 3 to FeO with Fe 3 O 4 being the intermediate product) as well. Application of the developed model to practical systems validated that its predicted values agreed very well with the experimental data in literatures.

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Gaseous reduction of iron oxides: Part IV. mathematical analysis of partial internal reduction-diffusion control

Cited by 62 publications

References 9 publications

Isothermal Reduction Kinetics of Powdered Hematite and Calcium Ferrite with CO–N<sub>2</sub> Gas Mixtures

Isothermal Reduction Kinetics of Powdered Hematite and Calcium Ferrite with CO–N<sub>2</sub> Gas Mixtures

Simulation Study on Performance of Z-path Moving-fluidized Bed for Gaseous Reduction of Iron Ore Fines

A Model for the Reduction of Metal Oxides by Carbon Monoxide

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