Die Reduktion von Eisenerzen mit Wasserstoff im Zweikomponenten-Fluidatbett

Wenzel, Werner; Block, Franz Rudolf; Wortberg, Ernst

doi:10.1002/srin.197204468

Cited by 3 publications

(2 citation statements)

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“…[5][6][7][8][9][10][11][12][13] The reduction processes use a reducing gas produced by steam reforming of natural gas. Therefor the reducing gas is a mixture of H 2 , CO, CO 2 , CH 4 , N 2 and H 2 O.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study on the Kinetics of Fluidized Bed Iron Ore Reduction.

Habermann¹,

Winter²,

Hofbauer³

et al. 2000

ISIJ International

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To optimize existing iron ore reduction processes or to develop new ones, it is necessary to know the reduction kinetics of the iron ore of interest under the relevant operating conditions. In this work the reduction kinetics of hematite fine iron ore was studied for industrial-scale processes using the fluidized bed technology. Especially designed batch tests were performed in a laboratory-scale fluidized bed reactor fluidized with H 2 , H 2 O, CO, CO 2 , N 2 at atmospheric and elevated pressures to simulate the relevant process conditions. To obtain the reduction rates and the degree of reduction, the concentrations of H 2 O, CO, and CO 2 in the outlet gas were analyzed by FT-IR spectroscopy.Preliminary reduction tests showed a strong effect of the sample weight on the reduction rates, especially in the early stages of reduction. The optimum sample weight was determined by partly replacing the hematite with silica sand. Additionally, the silica sand provided a constant and stable flow pattern throughout the reduction tests. The effects of temperature, gas composition, particle size and pressure on the rates of reduction were tested and discussed.Rate analysis showed the existence of two phases with different rates during the reduction tests. Additional investigations (microscope analysis, SEM) demonstrated that in the first phase the rates were controlled by mass transport in the gas phase and in the second phase by the reduction process within the small grains of the iron ore particles.KEY WORDS: iron ore reduction; high temperature fluidized bed; reduction kinetics; elevated pressure; H 2 -CO gas mixture.

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Section: Introductionmentioning

confidence: 99%

An Experimental Study on the Kinetics of Fluidized Bed Iron Ore Reduction.

Habermann¹,

Winter²,

Hofbauer³

et al. 2000

ISIJ International

View full text Add to dashboard Cite

show abstract

“…[4][5][6][7][8][9][10][11][12] The reduction processes use reducing gas produced by steam reforming of natural gas consisting of H 2 , H 2 O, CO, CO 2 , N 2 and CH 4 . Thus a strong interest in kinetics of reduction by a reducing gas containing CO 2 , CO and CH 4 exists.…”

Section: Introductionmentioning

confidence: 99%

Reduction Behavior of Hematite to Magnetite under Fluidized Bed Conditions

et al. 2004

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Reduction kinetic tests of Mt. Newman hematite ore from Western Australia were carried out in a laboratory-scale fluidized bed reactor at temperatures from 623 to 873 K and an absolute pressure of 10 bar. The reducing gas mixture was thermodynamically in equilibrium with magnetite and consisted of a mixture of H 2 , H 2 O, CO, CO 2 and CH 4 . The effect of temperature and residence time was studied. The original ore and its mineralogical and petrographical changes with increasing reduction time were analyzed. A reflected-light microscope technique with CCD-camera was used to determine the progress and the mechanism of reduction. According to the mineralogy and texture the ore could be classified in four types (coarse hematite, microplaty hematite, limonite and martite) with different reduction characteristics. Limonite and martite showed better reducibility than coarse and fine hematite.At all ore types the growth of dense magnetite rims was observed. The thickness of these layers was found to be linear proportional to reduction time. After analyzing the single steps of the reduction process the phase interface reaction turned out to be rate controlling between 673 and 773 K. Its activation energy is 91 kJ/mol. KEY WORDS: iron ore reduction; fluidized bed; hematite; magnetite; elevated pressure; rate controlling step.

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