scholarly journals Analysis of Iron Oxide Reduction Kinetics in the Nanometric Scale Using Hydrogen

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1276 ◽  
Author(s):  
Swathi K. Manchili ◽  
Johan Wendel ◽  
Eduard Hryha ◽  
Lars Nyborg
Keyword(s):  
Activation Energy ◽  
Iron Oxide ◽  
Reaction Kinetics ◽  
Reduction Process ◽  
Steel Powder ◽  
Surface Oxide ◽  
Oxide Reduction ◽  
Sintering Aid ◽  
Surface Iron ◽  
Reported Data

Iron nanopowder could be used as a sintering aid to water-atomised steel powder to improve the sintered density of metallurgical (PM) compacts. For the sintering process to be efficient, the inevitable surface oxide on the nanopowder must be reduced at least in part to facilitate its sintering aid effect. While appreciable research has been conducted in the domain of oxide reduction of the normal ferrous powder, the same cannot be said about the nanometric counterpart. The reaction kinetics for the reduction of surface oxide of iron nanopowder in hydrogen was therefore investigated using nonisothermal thermogravimetric (TG) measurements. The activation energy values were determined from the TG data using both isoconversional Kissinger–Akahira–Sunose (KAS) method and the Kissinger approach. The values obtained were well within the range of reported data. The reaction kinetics of Fe2O3 as a reference material was also depicted and the reduction of this oxide proceeds in two sequential stages. The first stage corresponds to the reduction of Fe2O3 to Fe3O4, while the second stage corresponds to a complete reduction of oxide to metallic Fe. The activation energy variation over the reduction process was observed and a model was proposed to understand the reduction of surface iron oxide of iron nanopowder.

scholarly journals Influence of Cerium on the Reduction Behaviour of Iron Oxide by Using Carbon Monoxide: TPR and Kinetic Studies

2019 ◽  
Author(s):  
Tengku Shafazila Tengku Saharuddin ◽  
Nurul Syahira Ezzaty Nor Azman ◽  
Fairous Salleh ◽  
Alinda Samsuri ◽  
Rizafizah Othaman ◽  
...  
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Iron Oxide ◽  
Reduction Process ◽  
Kinetic Studies ◽  
Xrd Analysis ◽  
Oxide Reduction ◽  
Iron Oxide Reduction ◽  
Reduction Behaviour ◽  
Lower Temperature

Reduction of iron oxide is one of the most studied topics owing to the importance of iron/steel industry and also has been used as a precursor and active component in a number of important chemical processes. The interaction between iron oxide and other metal additive have gained interest in the past two decades due to the ability on enhancing the reduction performance of the iron oxide. Therefore, this study was undertaken to investigate the influence of cerium on the reduction behaviours of iron oxide by (10%, v/v) carbon monoxide in nitrogen. The cerium doped (Ce-Fe2O3) and non-doped iron oxide reduction behaviour and the kinetic studies have been studied by temperature programmed reduction (TPR) and the phases formed of partially and completely reduced samples were characterized by X-ray diffraction spectroscopy (XRD) while the activation energy values were calculated from Arrhenius equation using Wimmer’s method. TPR results indicate that the reduction of doped and undoped iron oxide proceeds in three steps reduction (Fe2O3 ? Fe3O4 ? FeO ? Fe), while doped iron oxide showed a large shifted towards lower temperature especially in the transition steps of FeO ? Fe. Furthermore, TPR results also suggested that by adding Ce metal into iron oxide the reduction of metal iron completed at lower temperature (700 ?C) compared to non-doped iron oxide (900 ?C). Meanwhile, XRD analysis indicated that doped iron oxide composed of Fe2O3 and a small amount of FeCe2O4. The increase in the rates of iron oxide reduction may relate to the presence of cerium species in the formed of FeCe2O4 and was confirmed by the decrease in the activation energy regarding to all transition phases (Fe2O3 ? Fe3O4 ? FeO ? Fe) during the reduction process

scholarly journals Solid-State Kinetic Investigations of Nonisothermal Reduction of Iron Species Supported on SBA-15

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
N. S. Genz ◽  
D. Baabe ◽  
T. Ressler
Keyword(s):  
Activation Energy ◽  
Iron Oxide ◽  
Solid State ◽  
Apparent Activation Energy ◽  
Reduction Process ◽  
Kissinger Method ◽  
Iron Loading ◽  
Iron Species ◽  
Vis Spectroscopy ◽  
Model Independent

Iron oxide catalysts supported on nanostructured silica SBA-15 were synthesized with various iron loadings using two different precursors. Structural characterization of the as-prepared FexOy/SBA-15 samples was performed by nitrogen physisorption, X-ray diffraction, DR-UV-Vis spectroscopy, and Mössbauer spectroscopy. An increasing size of the resulting iron species correlated with an increasing iron loading. Significantly smaller iron species were obtained from (Fe(III), NH4)-citrate precursors compared to Fe(III)-nitrate precursors. Moreover, smaller iron species resulted in a smoother surface of the support material. Temperature-programmed reduction (TPR) of the FexOy/SBA-15 samples with H2 revealed better reducibility of the samples originating from Fe(III)-nitrate precursors. Varying the iron loading led to a change in reduction mechanism. TPR traces were analyzed by model-independent Kissinger method, Ozawa, Flynn, and Wall (OFW) method, and model-dependent Coats-Redfern method. JMAK kinetic analysis afforded a one-dimensional reduction process for the FexOy/SBA-15 samples. The Kissinger method yielded the lowest apparent activation energy for the lowest loaded citrate sample (Ea ≈ 39 kJ/mol). Conversely, the lowest loaded nitrate sample possessed the highest apparent activation energy (Ea ≈ 88 kJ/mol). For samples obtained from Fe(III)-nitrate precursors, Ea decreased with increasing iron loading. Apparent activation energies from model-independent analysis methods agreed well with those from model-dependent methods. Nucleation as rate-determining step in the reduction of the iron oxide species was consistent with the Mampel solid-state reaction model.

scholarly journals Machanism of Iron Oxide Reduction and Heat Transfer in the Smelting Reduction Process with a Thick Layer of Slag.

1992 ◽  
Vol 32 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Hiroyuki Katayama ◽  
Takamasa Ohno ◽  
Masao Yamauchi ◽  
Michitaka Matsuo ◽  
Takafumi Kawamura ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Iron Oxide ◽  
Reduction Process ◽  
Thick Layer ◽  
Oxide Reduction ◽  
Smelting Reduction ◽  
Iron Oxide Reduction

Neural network approximation of iron oxide reduction process

2005 ◽  
Vol 44 (7) ◽  
pp. 775-783 ◽  
Author(s):  
Tomasz Wiltowski ◽  
Krzysztof Piotrowski ◽  
Hana Lorethova ◽  
Lubor Stonawski ◽  
Kanchan Mondal ◽  
...  
Keyword(s):  
Neural Network ◽  
Iron Oxide ◽  
Reduction Process ◽  
Oxide Reduction ◽  
Iron Oxide Reduction

scholarly journals Mechanochemical Activation Effect on Technogenic Iron Oxide Reduction Kinetics

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 320
Author(s):  
Oleg Sheshukov ◽  
Mikhail Mikheenkov ◽  
Larisa Vedmid ◽  
Denis Egiazaryan
Keyword(s):  
Iron Oxide ◽  
Reaction Kinetics ◽  
Iron Oxides ◽  
Mechanochemical Activation ◽  
Solid Phase ◽  
Experimental Studies ◽  
High Rate ◽  
Oxide Reduction ◽  
Iron Oxide Reduction ◽  
Kinetics Of

Understanding the reaction kinetics of iron oxide reduction by carbon is a key task of the theory of metallurgical processes. One of the understudied features of the reaction kinetics of iron oxide solid-phase reduction by carbon is the discrepancy between the reacting substances’ small contact area and the process’s high rate. A convincing theoretical and experimental explanation of this effect has not yet been obtained. The data obtained earlier show that an increase in the scale of the briquetting pressure from 0 to 300 MPa increases the degree of its metallization during heating two-fold, and the metallization temperature decreases by more than 40 °C. Therefore, it was assumed that these effects during heating are a consequence of the mechanochemical activation (MCA) of iron oxides in the scale during its pressing. This paper presents the results of experimental studies on the influence of two types of scale MCA (grinding and pressing) on iron oxide reduction. The study of the MCA effect on the reaction kinetics of scale iron oxide reduction by carbon is a promising way to assess the criteria for scale phase composition changes under external factors. The presented results indicate a decrease in the amount of trivalent iron oxide (Fe2O3) after the MCA and an increase in the amount of one-and-a-half oxide (Fe3O4) and bivalent iron oxide (FeO). The obtained experimental data show that the initial stage of iron oxide reduction, consisting in the transition from higher iron oxides to lower ones, is possible at room temperature without carbon presence.

Kinetic analysis of iron oxide reduction in top gas recycling oxygen blast furnace

2012 ◽  
Vol 39 (5) ◽  
pp. 313-317 ◽  
Author(s):  
Y H Han ◽  
J S Wang ◽  
R Z Lan ◽  
L T Wang ◽  
X J Zuo ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Iron Oxide ◽  
Kinetic Analysis ◽  
Oxide Reduction ◽  
Iron Oxide Reduction ◽  
Oxygen Blast Furnace ◽  
Oxygen Blast ◽  
Top Gas Recycling ◽  
Gas Recycling

In situ surface oxide reduction with pulsed arc discharge for maximum adhesion of diamond-like carbon coatings

2008 ◽  
Vol 17 (12) ◽  
pp. 2071-2074 ◽  
Author(s):  
Veli-Matti Tiainen ◽  
Antti Soininen ◽  
Esa Alakoski ◽  
Yrjö T. Konttinen
Keyword(s):  
Arc Discharge ◽  
Surface Oxide ◽  
Diamond Like Carbon ◽  
Oxide Reduction ◽  
Carbon Coatings ◽  
Pulsed Arc Discharge ◽  
Pulsed Arc
Sign in / Sign up

Export Citation Format

Share Document