Topochemical Aspects of Iron Ore Reduction

Bitsianes, G.; Joseph, Tomi

doi:10.1007/bf03377553

Cited by 11 publications

(9 citation statements)

References 2 publications

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“…Compared with coprecipitation, homogeneous precipitation generally leads to LDH products in high crystallinity due to homogenous nucleation and growth procedure [39,40]. On the other hand, topochemical oxidation, a newly developed process involving a topotactic oxidative intercalation, started from brucite-like divalent metal hydroxides [41]. Using cobalt chloride (CoCl 2 •6H 2 O) and ferrous chloride (FeCl 2 •4H 2 O) as the precursors, Ma et al [42] developed a new process to synthesize transition-metal-bearing LDHs; brucite-like Co 2+ -Fe 2+ hydroxide was firstly synthesized via HMT hydrolysis under nitrogen protection, and the product was later transformed to Co 2/3 Fe 1/2 (OH) 2 LDH via topotactic oxidative intercalation with iodine in chloroform (I 2 /CHCl 3 ).…”

Section: Synthesis Of Layered Precursor Compoundsmentioning

confidence: 99%

2D Layered Double Hydroxide Nanosheets and Their Derivatives Toward Efficient Oxygen Evolution Reaction

et al. 2020

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Section: Synthesis Of Layered Precursor Compoundsmentioning

confidence: 99%

2D Layered Double Hydroxide Nanosheets and Their Derivatives Toward Efficient Oxygen Evolution Reaction

et al. 2020

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“…Journal directly proportional to the porosity of the ore specimen, which strongly indicates a diffusion controlled reaction. Bitsianes and Joseph (2) and Edstrom (6) have offered theories that the conversion of hematite and magnetite to wiistite results from gas penetration to all the solid-phase interfaces. Countercurrent diffusion of carbon monoxide inward and of carbon dioxide outward through the porous solid phases is possible under partial pressure gradients which are imposed by equilibrium gas mixtures at the respective solid-phase interfaces.…”

Section: Diffusion Of Iron Ions Of Oxygenmentioning

confidence: 99%

Kinetics of reduction of iron oxide with carbon monoxide and hydrogen

Kawasaki¹,

Sanscrainte²,

Walsh³

1962

AIChE Journal

124

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Case I n s t i t u t e of Technology, Cleveland, O h i o This investigation was undertaken to determine the rate controlling step i n the reduction of iron oxides with hydrogen and carbon monoxide. For the reduction of porous hemotite pellets, and bars it was found that the reduction rate is controlled by the counterdiffusion of reactant gas and product gas between the reaction zone and the main gas stream.The reduction specimens were spheres ranging i n size from 1.5-to 4.4-cm. diameter and 5.1-by 7.6-cm. bars either 0.69 or 1.24 cm. thick. They were prepared from electrolytic iron powder, partially oxidized i n a rotary kiln. The final oxidation of the specimens to hematite was accomplished by firing them a t 1,149OC. i n an oxidizing atmosphere. The bulk density was 3.5 g./cc. The specific surface area was 0.08 sq.m./g. and the void faction was 0.31. The oxide specimens were reduced i n streams of pure hydrogen or carbon monoxide a t temperatures between 700' and 1,200OC. The reduction was followed by measuring the sample weight during the reaction. Reduction rates were studied a t system pressures of 1 and 2 at. The samples reduced step by step, to magnetite, t o wiistite, and finally to iron. A shell of reduction, clearly visible i n sections of partially reduced specimens, moved concentrically into the core of the samples. Ahead of the receding interface the specimens were known to be pervious to the reactant gases. This led to the conclusion that the gas composition a t the interface was in equilibrium with the oxide phases present.Except for the removal of the last portions of oxygen a t the lower reduction temperatures, the course of the reduction followed Fick's first law of diffusion. Values of the diffusion coefficients, determined from the experimental data, were i n close agreement with values predicted from empirical equations. Varying the total pressure of the system hod no effect on the rate of reduction, which i s consistent with the equations developed from Fick's law for the diffusion-cantrolled reaction under investigation.It is speculated that the retarding of the reduction reaction a t the lower reduction temperatures is due t o the entrapment of oxide inside shells of iron, which are impervious to the reducing gas. Reduction of the trapped oxide then proceeds by solid state diffusion in a manner proposed by Edstrom (6).

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“…Hence, the iron and steel industries are trying to reduce carbon dioxide emissions and make the iron production process more environmental-friendly by developing new technologies [2]. Among the technologies being developed in this regard, hydrogen as a reducing agent [3][4][5][6], carbon capture and storage (CCS) [7,8], carbon capture and utilization (CCU) [9,10], biomass as a reducing agent [11,12], and electrolysis can be mentioned [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…There are usually three kinetic-controlling mechanisms of diffusion through the gas film layer, diffusion through the ash layer, and the chemical reaction for these reactions (Figure 1). Hence, five steps can be considered for iron ore reduction by hydrogen [3,20,21]:…”

Section: Introductionmentioning

confidence: 99%

A Review on the Kinetics of Iron Ore Reduction by Hydrogen

et al. 2021

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A clean energy revolution is occurring across the world. As iron and steelmaking have a tremendous impact on the amount of CO2 emissions, there is an increasing attraction towards improving the green footprint of iron and steel production. Among reducing agents, hydrogen has shown a great potential to be replaced with fossil fuels and to decarbonize the steelmaking processes. Although hydrogen is in great supply on earth, extracting pure H2 from its compound is costly. Therefore, it is crucial to calculate the partial pressure of H2 with the aid of reduction reaction kinetics to limit the costs. This review summarizes the studies of critical parameters to determine the kinetics of reduction. The variables considered were temperature, iron ore type (magnetite, hematite, goethite), H2/CO ratio, porosity, flow rate, the concentration of diluent (He, Ar, N2), gas utility, annealing before reduction, and pressure. In fact, increasing temperature, H2/CO ratio, hydrogen flow rate and hematite percentage in feed leads to a higher reduction rate. In addition, the controlling kinetics models and the impact of the mentioned parameters on them investigated and compared, concluding chemical reaction at the interfaces and diffusion of hydrogen through the iron oxide particle are the most common kinetics controlling models.

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Topochemical Aspects of Iron Ore Reduction

Cited by 11 publications

References 2 publications

2D Layered Double Hydroxide Nanosheets and Their Derivatives Toward Efficient Oxygen Evolution Reaction

2D Layered Double Hydroxide Nanosheets and Their Derivatives Toward Efficient Oxygen Evolution Reaction

Kinetics of reduction of iron oxide with carbon monoxide and hydrogen

A Review on the Kinetics of Iron Ore Reduction by Hydrogen

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