THE EFFECTS OF THE CHEMICAL AND PHYSICAL CHARACTERISTICS OF IRON OXIDES ON THE KINETICS OF THE CATALYZED REACTION, 2CARBON-MONOXIDE ---> CARBON + CARBON-DIOXIDE, IN SIMULATED BLAST FURNACE ATMOSPHERES

Persistent Link:
http://hdl.handle.net/10150/281920
Title:
THE EFFECTS OF THE CHEMICAL AND PHYSICAL CHARACTERISTICS OF IRON OXIDES ON THE KINETICS OF THE CATALYZED REACTION, 2CARBON-MONOXIDE ---> CARBON + CARBON-DIOXIDE, IN SIMULATED BLAST FURNACE ATMOSPHERES
Author:
Lowry, Michael Lee
Issue Date:
1980
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Seven iron ore pellets, two sinters, and one lump ore were studied in CO-CO₂-H₂-N₂ atmospheres from 350°C to 750°C, simulating the upper stack of the ironmaking blast furnace. Experiments were performed in a flowing gas reactor on single specimens of each type of substrate. Two different measurements were made: (1) the carbon deposition and concurrent iron oxide reduction rate at 550°C in 30%CO, 10%CO₂, 2%H₂, and 58%N₂; and (2) the amount of carbon deposited during a programmed increase in temperature and change in CO-CO₂ ratio simulating the descent of an ore specimen in the blast furnace stack. The rates of the concurrent reaction were determined from mass balances based on gas chromatographic analyses of the CO, CO₂H₂, and N₂ in both the inlet and outlet gases and the continuously recorded mass of the specimen. The materials were examined as to chemical composition, internal structure, porosity, and surface area. Elemental analyses of single iron oxide grains were made by electron microprobe. Slag materials and composition, and crystallinity were determined by microprobe and X-ray diffraction. The results of the experiments show that carbon deposition occurs only in the presence of metallic iron which is produced from the concurrent reduction of Fe₃O₄. The degree of reduction is controlled largely by the structure of the substrate, but the carbon deposition is controlled only by the chemical composition of the substrate--specifically, silicon in the iron and the CaO to MgO ratio. In the blast furnace simulation, the carbon deposition increases for pellets fluxed with dolomite to a maximum with lime-fluxed pellets. The effects of H₂ and CO₂ on the reactions were investigated in the isothermal experiments using an Empire pellet. The CO₂ controlled only the reduction, and this by diffusion of the CO₂. The hydrogen in very small amounts enhanced the deposition of carbon, probably by eliminating the presence of the inactive iron carbides. Under blast furnace conditions, the changes in the operation when the chemistry of the ore feed is changed to fluxed pellets will be due more to the shifts in the available heat within the stack from carbon deposition than to the low temperature reduction of the ores, which does not change with the addition of the flux materials.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Blast furnaces.; Iron oxides.; Iron -- Metallurgy.; Reduction (Chemistry)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Metallurgical Engineering
Degree Grantor:
University of Arizona
Advisor:
Bronson, Arturo; Geiger, Gordon H.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleTHE EFFECTS OF THE CHEMICAL AND PHYSICAL CHARACTERISTICS OF IRON OXIDES ON THE KINETICS OF THE CATALYZED REACTION, 2CARBON-MONOXIDE ---> CARBON + CARBON-DIOXIDE, IN SIMULATED BLAST FURNACE ATMOSPHERESen_US
dc.creatorLowry, Michael Leeen_US
dc.contributor.authorLowry, Michael Leeen_US
dc.date.issued1980en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractSeven iron ore pellets, two sinters, and one lump ore were studied in CO-CO₂-H₂-N₂ atmospheres from 350°C to 750°C, simulating the upper stack of the ironmaking blast furnace. Experiments were performed in a flowing gas reactor on single specimens of each type of substrate. Two different measurements were made: (1) the carbon deposition and concurrent iron oxide reduction rate at 550°C in 30%CO, 10%CO₂, 2%H₂, and 58%N₂; and (2) the amount of carbon deposited during a programmed increase in temperature and change in CO-CO₂ ratio simulating the descent of an ore specimen in the blast furnace stack. The rates of the concurrent reaction were determined from mass balances based on gas chromatographic analyses of the CO, CO₂H₂, and N₂ in both the inlet and outlet gases and the continuously recorded mass of the specimen. The materials were examined as to chemical composition, internal structure, porosity, and surface area. Elemental analyses of single iron oxide grains were made by electron microprobe. Slag materials and composition, and crystallinity were determined by microprobe and X-ray diffraction. The results of the experiments show that carbon deposition occurs only in the presence of metallic iron which is produced from the concurrent reduction of Fe₃O₄. The degree of reduction is controlled largely by the structure of the substrate, but the carbon deposition is controlled only by the chemical composition of the substrate--specifically, silicon in the iron and the CaO to MgO ratio. In the blast furnace simulation, the carbon deposition increases for pellets fluxed with dolomite to a maximum with lime-fluxed pellets. The effects of H₂ and CO₂ on the reactions were investigated in the isothermal experiments using an Empire pellet. The CO₂ controlled only the reduction, and this by diffusion of the CO₂. The hydrogen in very small amounts enhanced the deposition of carbon, probably by eliminating the presence of the inactive iron carbides. Under blast furnace conditions, the changes in the operation when the chemistry of the ore feed is changed to fluxed pellets will be due more to the shifts in the available heat within the stack from carbon deposition than to the low temperature reduction of the ores, which does not change with the addition of the flux materials.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectBlast furnaces.en_US
dc.subjectIron oxides.en_US
dc.subjectIron -- Metallurgy.en_US
dc.subjectReduction (Chemistry)en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineMetallurgical Engineeringen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorBronson, Arturoen_US
dc.contributor.advisorGeiger, Gordon H.en_US
dc.identifier.proquest8110124en_US
dc.identifier.oclc8625540en_US
dc.identifier.bibrecord.b13878918en_US
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