Reactions of sinter in a lead blast furnace
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I.
INTRODUCTION
IN an earlier paper,1 a series of probing experiments was described by which simultaneous measurements were made of gas composition, temperature, and pressure within the lead blast fumace of Brunswick Mining & Smelting Ltd., Belledune, New Brunswick, Canada. These measurements were interpreted in terms of an oxygen potential, /Xo2, diagram for the bulk gas phase. The diagram included the equilibrium oxygen potential for various relevant metal/ metal oxide systems. From this diagram, the thermodynamic driving force, in terms of a difference in oxygen potential, A/-~o:for the various reduction reactions was evident. In particular, the thermodynamic driving force for the reduction of lead oxide was noted to be large (11501 to 12001kJ mol-~); the corresponding value for the reduction of magnetite to wustite was 150 J to 1100 ] kJ mol -~, through the bed of the furnace. However, as is well known, the thermodynamic driving force cannot be used as a measure of the rate of a reaction; it is generally accepted that at temperatures less than about 700 ~ the various reactions are essentially frozen due to the high activation energies associated with the reactions. In order to determine the extent of the chemical reactions of the sinter, an additional series of probing experiments was designed. This paper reports the results of this series and compares these results with the predictions of Chao z based upon a dynamic simulation of the blast furnace. Some additional measurements of gas composition, temperature, and pressure are also reported. II.
The probe used in this work shown in Figure 1 was similar to the water-cooled probe used by Chao e t a l . ~ modified in such a way that a cage, fabricated of Inconel 660, could be attached to the lower end. The overall length of the probe was about 11.5 m. A perforated thimble of Inconel 660 fitted with a chromel-alumel thermocouple was located inside the cage at approximately the mid point, to permit simultaneous measurements of gas composition, temperature, and pressure.
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EXPERIMENTAL
The blast furnace has been described elsewhere. ~ The only significant difference in operation is in respect of oxygen enrichment of the blast air; this is enriched such that the oxygen concentration is about 23 pct. DAVID R. MORRIS is Professor, Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick, Canada. BRENT R. AMERO is Technical Assistant, Montreal Engineering Ltd., Calgary, Alberta, Canada. PHILIP G. EVANS is Technical Superintendent, Brunswick Mining & Smelting Corporation, Ltd., Belledune, New Brunswick, Canada. WILLIAM PETRUK, Research Scientist, and D. R. OWENS, Technician, are with the Department of Energy, Mines and Resources, Ottawa, Ontario, Canada. Manuscript submitted February 14, 1983. METALLURGICAL TRANSACTIONS B
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Fig. 1 --Probe used in lead blast furnace. (1) Thermocouple and gas sampiing ports. (2) Water coolant connections. (3) Lifting lugs. (4) Threaded end block for attachment of cage. (5) Loca
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