REDUCTION AND SWELLING OF FIRED HEMATITE IRON ORE PELLETS BY NON−COKING COAL FINES FOR APPLICATION IN SPONGE IRONMAKING

Abstract:

In the present investigation, the reduction and swelling behaviours ( in low grade coal ) of fired iron ore pellets, prepared by blending hematite iron ore fines of –100, –18+25 and –10+16 mesh sizes in different proportions, have been studied in the temperature range of 850 – 10000C with an objective to promote massive utilization of fines in sponge ironmaking. An increase in temperature up to the range studied ( 850 – 10000C ) substantially enhanced the reduction rate and the rate was found to be highest in the first 15 – 30 min at all these temperatures. All the fired pellets, made by mixing iron ore particles of ±100 mesh size, have shown approximately the same reduction rates and slightly higher swelling indices than those made from fines of –100 mesh size only. In all the fired pellets reduced at temperatures of 850 and 9000C, the results indicated an increase in the extent of swelling with reduction time. Maximum swelling was obtained in the fired pellets at a reduction temperature of 9000C, followed by a decrease thereafter. Reduction of fired pellets at temperatures of 950 and 10000C exhibited shrinkage in their reduced products, and the extent of this shrinkage increased with increase in exposure time.

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