TG/DTA study on the carbon monoxide and graphite thermal reduction of a high-grade iron nickel oxide residue with the presence of siliceous gangue

Yu, Dawei; Zhu, Mingqian; Utigard, T. A.; Barati, Mansoor

doi:10.1016/j.tca.2013.10.015

Cited by 24 publications

(20 citation statements)

References 28 publications

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“…Reduction of Fe 2 O 3 ─NiO by solid C powder has been reported to be controlled through chemical reactions at temperatures above 1100°C, where enough CO is produced to satisfy the reduction by a gas agent reducer . Similar result has been reported in another work …”

Section: Resultssupporting

confidence: 83%

“…41 Similar result has been reported in another work. 42 An interesting finding in the present work was that the diffusion of the reducing agent or the gaseous products did not act as the controlling mechanism in any of the reaction steps. This can be due to the small size of the powders, as well as the small amount of sample used in the TGA.…”

Section: The Mechanism Of Isothermal Reduction and Carburizationmentioning

confidence: 59%

“…It is believed that the reduction by H 2 is controlled by either chemical reaction or gas diffusion, depending on the type of oxide, temperature, particle size, and gas concentration. The small amount of material prevents a considerable concentration gradient for CO in the materials bed . In comparison, a diffusion model of D 1 could explain the kinetics of reduction of WO 3 to W by H 2 in a study performed by Fouad, where fine powdered oxide with surface area of 20 m 2 g −1 was used.…”

Section: Resultsmentioning

confidence: 99%

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Kinetics of nonisothermal reduction and carburization of WO₃─NiO nano‐composite powders by CO─CO₂

Mohammadzadeh

Rezaie

Barati

et al. 2019

Int J of Chemical Kinetics

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The kinetics of simultaneous reduction and carburization of WO3─NiO nanocomposite powders by CO/CO2 was studied using a nonisothermal thermogravimetric analysis. The experiments were carried out at heating rates between 5 and 15°C/min, showing that the thermochemical processes can be divided into four steps, each dominated by a reaction, as following: NiO → Ni, WO3 → WO2, WO2 → W, and W → WC. The apparent activation energy for each step was obtained based on the Flynn‐Wall‐Ozawa isoconversional method for the individual steps, and the kinetic model was assessed by fitting master plots of various kinetic models for these steps at different heating rates. The Avrami‐Erofeev kinetic model was found to fit to the third and fourth steps and main part of the first, and the geometric contracting model fitted the best for the second step. Changing the heating rate did not affect the master plots of the third step. However, for the first step, increasing the heating rate made the Avrami‐Erofeev model the best‐fitting correlation and also for the second step the matching model changed at the highest heating rate (15°C/min) from a two‐dimensional contracting model (cylindrical particles) to a three‐dimensional contracting model (spherical particles).

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Section: Resultssupporting

confidence: 83%

Section: The Mechanism Of Isothermal Reduction and Carburizationmentioning

confidence: 59%

Section: Resultsmentioning

confidence: 99%

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Kinetics of nonisothermal reduction and carburization of WO₃─NiO nano‐composite powders by CO─CO₂

Mohammadzadeh

Rezaie

Barati

et al. 2019

Int J of Chemical Kinetics

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“…5 shows a faster complete conversion (total fraction reactes equals unity) with smaller pellet size during reduction tests. This result indicates that mass transfer into the pores is present on the reduction [24]. Furthermore, it was noted a change on reaction rate above 750°C.…”

Section: Effect Of Reducing Gas Flow and Pellet Sizementioning

confidence: 71%

Synthetic zinc ferrite reduction by means of mixtures containing hydrogen and carbon monoxide

Junca

Oliveira

Restivo

et al. 2015

J Therm Anal Calorim

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Solid waste generation is one of the main problems in the steelmaking process. One of the most problematic waste products is the electric arc furnace dust, which is a by-product rich in iron and zinc and is present as zincite (zinc oxide) or franklinite (zinc ferrite). This work focuses on the reduction kinetics of synthetic zinc ferrite by gases containing hydrogen and carbon monoxide. This process was examined via forced stepwise isothermal analysis. The test was conducted at temperatures ranging from 500 to 950°C. Reduction of zinc was accomplished using a mixture of hydrogen and carbon monoxide in order to simulate reformed natural gas. The results indicated that reduction of zinc ferrite occurred in two stages (550-750°C and 800-900°C). The first stage was characterized by iron oxide reduction, where a mix control between nucleation and diffusion was determined. The apparent activation energy obtained was 71.5 kJ mol -1 . The second stage was characterized by zinc oxide reduction, where the controlling mechanism was identified as a mixed control between diffusion and phase boundary reaction. The apparent activation energy was 135.5 kJ mol -1 . The formation of a dense layer of metallic iron around the unreacted core may have caused the apparent activation energy to increase.

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“…Furthermore, this dependence may indicate the reaction takes place from the surface to the particle core due to limited mass transfer in the pores. In this case, the reaction rate can be controlled by gas diffusion through pores [36,37]. Figure 4 shows da/dt x t relationship to EAFD pellets reduction under simulated reformed natural gas.…”

Section: Thermogravimetric Analysismentioning

confidence: 99%

Reduction of electric arc furnace dust pellets by simulated reformed natural gas

Junca

Restivo

Oliveira

et al. 2016

J Therm Anal Calorim

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The purpose of this paper is to study the kinetic reaction of electric arc furnace dust pellets using a reducing gas simulating the reformed natural gas. The kinetic investigation was accomplished via forced stepwise isothermal analysis method. The tests were programmed in the range of 500-1000°C. It was used a reducing gas contained 25 % of CO and 75 % of H 2 . X-ray patterns were analyzed in order to understand the reduction process. The results show the reduction of electric arc furnace dust pellet occurs in three steps. At 550-650°C, the zinc ferrite is reduced to magnetite and zinc oxide, followed by the reduction of magnetite to wustite. Carbon deposition on the pellet surface was detected in this step, which impairs the kinetic analysis. In the range of 700-800°C, wustite is reduced to iron. It was determined a mixed control between nucleation and diffusion with E a of 89.2 kJ mol -1 . At 850-950°C, the main reaction is zinc oxide reduction to gaseous zinc. However, wustite reduction is also observed. The E a of 135.5 kJ mol -1 with a mixed control between diffusion and chemical reaction was detected.

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TG/DTA study on the carbon monoxide and graphite thermal reduction of a high-grade iron nickel oxide residue with the presence of siliceous gangue

Cited by 24 publications

References 28 publications

Kinetics of nonisothermal reduction and carburization of WO₃─NiO nano‐composite powders by CO─CO₂

Kinetics of nonisothermal reduction and carburization of WO₃─NiO nano‐composite powders by CO─CO₂

Synthetic zinc ferrite reduction by means of mixtures containing hydrogen and carbon monoxide

Reduction of electric arc furnace dust pellets by simulated reformed natural gas

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TG/DTA study on the carbon monoxide and graphite thermal reduction of a high-grade iron nickel oxide residue with the presence of siliceous gangue

Cited by 24 publications

References 28 publications

Kinetics of nonisothermal reduction and carburization of WO3─NiO nano‐composite powders by CO─CO2

Kinetics of nonisothermal reduction and carburization of WO3─NiO nano‐composite powders by CO─CO2

Synthetic zinc ferrite reduction by means of mixtures containing hydrogen and carbon monoxide

Reduction of electric arc furnace dust pellets by simulated reformed natural gas

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Product

Resources

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Kinetics of nonisothermal reduction and carburization of WO₃─NiO nano‐composite powders by CO─CO₂

Kinetics of nonisothermal reduction and carburization of WO₃─NiO nano‐composite powders by CO─CO₂