الفهرس 
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Abstract
During the fluidized bed reduction of iron ores to get sponge iron, the attrition (breakage, fragmentation and abrasion) of fluidized particles could be a serious problem in the design and operation of such systems. In the present work the fluidized bed reduction process of iron ores with hydrogen was studied with special emphasis on the attrition phenomenon. The parameters investigated were temperature, fluidizing / Teducing gas velocity, bed aspect ratio, and duration of the process. In addition, the particle attrition under non-reactive conditions (room and high temperatures) was investigated. The measurements included: % metallization, and particle size analysis, scanning electron microscopy was used for metallographic examinations.
At room temperature, the results obtained indicated that the prevailing attrition mechanism id abrasion. At high temperature, whether gradual or sudden heating, the attrition extent is much greater than that at room temperature and the different mechanisms: breakage, fatigue and abrasion exist. The highest attrition extent was observed during the reduction of iron ores under sudden heating conditions, the extent increased with temperature.
An empirical model of the attrition process was developed which relates the attrition rate with the four main affecting parameters. The model predictions show an excellent agreement with the experimental data. The developed equations should be useful in the design and operation of the fluidized bed reduction process of iron ores.