Influence of the Application of a Sound Field on the Flow State Reduction of Newman Fine Iron Ore

To improve the fluidization of the fluidized bed in ironmaking, the particle loss and bonding during the fluidized bed are largely removed by changing the properties of the particle surface or by adding an external field. Currently, the vibration, magnetic, sound, and electric fields have been commonly applied to provide external energy to the fluidization bed systems. In this work, experiments are conducted for Newman ore particles under the application of an external sound field at a reduction temperature of 1023 K, linear velocity of 0.6 m/s, duration of 60 min, pressure of 0.2 MPa, and typical mineral powder particle size of 80–100 mesh, with H2 used as the reducing gas. The power and frequency of the ultrasonic field are varied, and the effects of sound field are evaluated by the comparative analysis of the effects of the sound field with different powers of sound fields and application times on the metallization rate and binder ratio of the samples. The acoustic pressure and frequency were varied to determine the critical speed and influence on the bed and to study the interactions of the iron ore powder particles in the sound field and the bonding mechanism of the particles. The results of this paper reproduce the actual particle fluidization process and analysis of the interactions of the particles in the sound field well. The influence of the external sound field on the gas-solid flow was studied from the perspective of macroscopic motion and force analysis.

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Influence of MgO Additive on Fluidized Bed Reduction of Iron Ore Fines under Simulate COREX Reducing Gas

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.567.96 ◽

2012 ◽

Vol 567 ◽

pp. 96-101

Author(s):

Jian Hua Shao ◽

Hui Qing Tang ◽

Zhan Cheng Guo

Keyword(s):

Reaction Time ◽

Fluidized Bed ◽

Metallic Iron ◽

Iron Ore ◽

Solution Method ◽

Carbon Deposition ◽

Particle Surface ◽

Reducing Gas ◽

Reduction Of Iron ◽

Iron Ore Fines

Influence of mixing MgO additive on fluidized bed reduction of iron ore fines using simulate COREX reducing gas was investigated. Experiments were conducted at 1073 K in a visualization fluidized bed. Mixing MgO additive was carried out using powder method and solution method. It was found that mixing MgO into ore fines using solution method could increase fluidization time from 12 to 80 minutes, and improve the metallization ratio from 22% to 81%. Reason was that coating MgO could effectively insulate the contact of metallic iron on particles, which provided the reaction time for carbon deposition and the production of Fe3C with low stickiness. Therefore, the decrease of metallic iron on particle surface led to the decrease of particle stickiness in fluidized bed reduction

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Effect of Prior Oxidation on the Reduction Behavior of Magnetite-Based Iron Ore During Hydrogen-Induced Fluidized Bed Reduction

Metallurgical and Materials Transactions B ◽

10.1007/s11663-021-02215-5 ◽

2021 ◽

Author(s):

Heng Zheng ◽

Daniel Spreitzer ◽

Thomas Wolfinger ◽

Johannes Schenk ◽

Runsheng Xu

Keyword(s):

Fluidized Bed ◽

Partial Oxidation ◽

Iron Ore ◽

Reduction Rate ◽

Deep Oxidation ◽

Initial Reaction ◽

Oxidation Treatment ◽

Rate Limiting Step ◽

Rate Limiting ◽

Prior Oxidation

AbstractMagnetite-based iron ore usually shows a high sticking tendency and a poor reducibility in the fluidized bed because of its dense structure. To enhance the fluidization and reduction behaviors of magnetite-based iron ore during hydrogen-induced fluidized bed reduction, the effect of a prior oxidation treatment is investigated. The results show that the untreated magnetite-based iron ore cannot be fluidized successfully in the tested temperature range between 600 °C and 800 °C. At 600 °C reduction temperature, the de-fluidization can be avoided by a prior oxidation treatment. At higher reduction temperatures, the fluidization behavior can be further improved by an addition of 0.5 wt pct MgO. Magnesiowüstite (FexMg1−xO) is formed, which decreases the contact chance of the sticky surface between particles. Regarding to the reduction rate, a prior partial oxidation is more beneficial compared to deep oxidation. The kinetic analysis shows that MgO could promote the initial reaction. The reaction rate limiting step is no longer diffusion but chemical reaction for prior partly oxidized samples. A prior partial oxidation combined with an addition of MgO is considered to be a promising pretreatment method for a successful processing of magnetite-based iron ore.

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Hydrodynamic behavior of iron ore particles in a circulating fluidized bed reduction system

Metals and Materials ◽

10.1007/bf03025920 ◽

1995 ◽

Vol 1 (2) ◽

pp. 99-105 ◽

Cited By ~ 4

Author(s):

Yoon-Bong Hahn ◽

In-Sik Nam ◽

Dae-Gyu Park ◽

II-Ok Lee

Keyword(s):

Fluidized Bed ◽

Iron Ore ◽

Circulating Fluidized Bed ◽

Hydrodynamic Behavior ◽

Reduction System

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Production of Free Radicals Arising from the Surface Activity of Minerals and Oxygen. Part I. Iron Mine Ores

Toxicology and Industrial Health ◽

10.1177/074823378900500613 ◽

1985 ◽

Vol 5 (6) ◽

pp. 1061-1078 ◽

Cited By ~ 19

Author(s):

Dominique Costa ◽

Joelle Guignard ◽

Roger Zalma ◽

Henri Pezerat

Keyword(s):

Surface Activity ◽

Iron Ore ◽

Particle Surface ◽

Radical Oxygen Species ◽

Lung Cancers ◽

Surface Sites ◽

Iron Mine ◽

Mineral Dusts ◽

Trapping Agent ◽

Excess Incidence

The excess incidence of lung cancers observed in many metal mines probably is not only correlated with radioactivity but also with the inhaled dusts. In an attempt to determine a possible mechanism of carcinogenicity related to the surface activity of dusts, using the spin-trapping agent and ESR spectroscopy, one can demonstrate that some mineral dusts from iron ore mines are very active in an oxidative process in aqueous medium, implying the formation of radical oxygen species on reducing surface sites of the solid. This reducing surface activity of the dusts depends on the presence of Fe2+ ion in the lattice and on the process of activation and passivation of the surface sites. The more simple process of activation is the dissolution of the oxidized coating on the particle surface. Among the oxides, oxyhydroxides, carbonates, and silicates, the magnesium-iron phyllosilicates (chlorite, biotite, berthierine) appear the most active. The siderite FeCO3 is also active, but the iron oxides and oxyhydroxides are generally nonactive.

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