STRUCTURAL CHANGES OCCURRING DURING REDUCTION OF HEMATITE AND MAGNETITE PELLETS CONTAINING COAL CHAR.

Abstract

The swelling observed at 900 and 1000 degree C was due to whisker growth outward from wustite surfaces due to a changing reducing potential of the gas phase within the pellet coupled with the presence of calcium oxide on the surface. Shrinkage at 1100 and 1200 degree C is accounted for in terms of sintering. Pellet strength decreased between 900 degree C and 1000 degree C and increased at higher temperatures. Weakness at low temperatures was due to the absence of bonding between whiskers. The high strength obtained at (1100 and 1200 degree C) was produced by sintering.