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|Title:||Silico-ferrite of calcium and aluminum (SFCA) iron ore sinter bonding phases: new insights into their formation during heating and cooling|
|Citation:||Webster, N. A. S., Pownceby, M. I., Madsen, I. C., & Kimpton, J. A. (2012). Silico-ferrite of calcium and aluminum (SFCA) iron ore sinter bonding phases: new insights into their formation during heating and cooling. Metallurgical and Materials Transactions B-Process Metallurgy and Materials Processing Science, 43(6), 1344-1357.|
|Abstract:||The formation of silico-ferrite of calcium and aluminum (SFCA) and SFCA-I iron ore sinter phases during heating and cooling of synthetic iron ore sinter mixtures in the range 298 K to 1623 K (25 A degrees C to 1350 A degrees C) and at oxygen partial pressure of 5 x 10(-3) atm has been characterized using in situ synchrotron X-ray diffraction. SFCA and SFCA-I are the key bonding phases in iron ore sinter, and an improved understanding of their formation mechanisms may lead to improved efficiency of industrial sintering processes. During heating, SFCA-I formation at 1327 K to 1392 K (1054 A degrees C to 1119 A degrees C) (depending on composition) was associated with the reaction of Fe2O3, 2CaO center dot Fe2O3, and SiO2. SFCA formation (1380 K to 1437 K [1107 A degrees C to 1164 A degrees C]) was associated with the reaction of CaO center dot Fe2O3, SiO2, and a phase with average composition 49.60, 9.09, 0.14, 7.93, and 32.15 wt pct Fe, Ca, Si, Al, and O, respectively. Increasing Al2O3 concentration in the starting sinter mixture increased the temperature range over which SFCA-I was stable before the formation of SFCA, and it stabilized SFCA to a higher temperature before it melted to form a Fe3O4 + melt phase assemblage (1486 K to 1581 K [1213 A degrees C to 1308 A degrees C]). During cooling, the first phase to crystallize from the melt (1452 K to 1561 K [1179 A degrees C to 1288 A degrees C]) was an Fe-rich phase, similar in composition to SFCA-I, and it had an average composition 58.88, 6.89, 0.82, 3.00, and 31.68 wt pct Fe, Ca, Si, Al, and O, respectively. At lower temperatures (1418 K to 1543 K [1145 A degrees C to 1270 A degrees C]), this phase reacted with melt to form SFCA. Increasing Al2O3 increased the temperature at which crystallization of the Fe-rich phase occurred, increased the temperature at which crystallization of SFCA occurred, and suppressed the formation of Fe2O3 (1358 K to 1418 K [1085 A degrees C to 1145 A degrees C]) to lower temperatures. © 2012, Springer.|
|Gov't Doc #:||5142|
|Appears in Collections:||Journal Articles|
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