Carbon Monoxide Reduction and Accompanying Swelling of Iron Oxide Compacts.

Nasr, M. I.; Omar, Adel A.; Hessien, M.M.; Ei-Geassy, A. A.

doi:10.2355/isijinternational.36.164

Cited by 61 publications

(34 citation statements)

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“…The Ea of each step from both macrokinetics and microkinetics have been calculated by many investigators. [21][22][23][24][25] The typical ranges of Ea of different rate controlling steps have been summarized by Strangway.…”

Section: Reduction Mechanismmentioning

confidence: 99%

Reduction Kinetics of Fine Hematite Ore Particles with a High Temperature Drop Tube Furnace

et al. 2015

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HIsarna is a new coal based smelting reduction process, which has the excellent features of using coal and fine hematite ore directly as raw materials instead of coke and pellet. In this context, the reduction kinetics of hematite ore fines in the smelting cyclone was studied in the laboratory scale. The gas-solid and gas-molten particle reduction behaviour were studied with a High-temperature Drop Tube Furnace (HDTF) and a combination of various characterization methods was used to track the kinetic behaviour such as chemical titration, optical microscope and Scanning Electron Microscope (SEM). A series of experiments with different reaction time (210-2 020 ms) has been conducted at different temperatures from 1 550 K to 1 750 K, thus enabling the kinetic study of the partially reduced hematite ore particles. It was found that a quantity of micro pores was formed during the reduction process mainly due to the loss of oxygen. The un-reacted shrinking core model could be used to describe both gas-solid particle reaction and gas-molten particle reaction.

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Section: Reduction Mechanismmentioning

confidence: 99%

Reduction Kinetics of Fine Hematite Ore Particles with a High Temperature Drop Tube Furnace

et al. 2015

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“…According to the literature study, the reduction rate is remarkably delayed within the specific temperature range of 650-750 o C and in the vicinity of 920 o C. This phenomenon has been explained in literature [ e.g. Tokuda et al (1973), Nasr et al (1996), Turkdogan et al (1971), El-Geassy et al (1977)] as the result of the obstruction of intraparticle diffusion on account of blockade of pores by agglomeration of Fe 3 O 4 particles with each other. This extreme kinetic behavior of the α in the temperature vicinity of 750 o C is reproduced by the model clearly (see slight decrease in Fig.…”

Section: Discussionmentioning

confidence: 95%

“…The pore structure formed and surface's morphology, determined by hematite-magnetite and magnetitewüstite consecutive transformations, can influence the overall process rate considerably in relatively complicated manner. The reaction's kinetics has been thoroughly investigated, both theoretically and experimentally, in order to evaluate the optimum process conditions [e.g., Nasr et al (1996), Turkdogan et al (1971), El-Geassy et al (1977)]. In spite of the effort no general, coherent kinetic equation which would be valid both in the surface and diffusion controlled ranges has been formulated till the present day [e.g., Hayes (1979), Kang et al (1996), Tokuda et al (1973)].…”

Section: Iron Oxide Reduction Processmentioning

confidence: 99%

Simultaneous influence of gas mixture composition and process temperature on Fe2O3->FeO reduction kinetics: neural network modeling

Piotrowski

Wiltowski

Mondal

et al. 2005

Braz. J. Chem. Eng.

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-The kinetics of Fe 2 O 3 →FeO reaction was investigated. The thermogravimetric (TGA) data covered the reduction of hematite both by pure species (nitrogen diluted CO or H 2 ) and by their mixture. The conventional analysis has indicated that initially the reduction of hematite is a complex, surface controlled process, however once a thin layer of lower oxidation state iron oxides (magnetite, wüstite) is formed on the surface, it changes to diffusion control. Artificial Neural Network (ANN) has proved to be a convenient tool for modeling of this complex, heterogeneous reaction runs within the both (kinetic and diffusion) regions, correctly considering influence of temperature and gas composition effects and their complex interactions. ANN's model shows the capability to mimic some extreme (minimum) of the reaction rate within the determined temperature window, while the Arrhenius dependency is of limited use.

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“…Regarding the reduction rate of iron ore, the effect of temperature 5) and the effect of H 2 6) were researched well by many researchers. But the reduction of PRI can be different with thaf of unreduced iron ore because PRI was made by being semi-reduced and compacted again.…”

Section: Isij 275mentioning

confidence: 99%