Mineralogy of iron ore pellet and its correlation with crushing strength

The mineralogical investigation of typical indurated pellets, which were generated through the pelletisation experiments of the concentrate from dump fines of
Gua Iron Ore mines of SAIL, has been reported in the present paper.
Pelletisation experiments were conducted with the iron ore concentrates (Fe = 65.1%) of
varying mesh of grind having the -45 micron size constituents 71, 81 and 93 wt.%
respectively. The crushing strength (CS) of the green pellets as well as heat hardened ones
was determined.
The CS of heat hardened pellets improved considerably with the concentrate which has
undergone very fine mesh of grind even at lower bentonite consumption. Besides, minor
amount of flux and coke could be incorporated during the course of pelletisation. Further
grinding of bentonite did help in the improvement of CS.
The crushing strength of the heat hardened pellet was correlated with its mineralogy.
Typically a significant change in the mineralogy was observed with reference to core,
intermediate and outer layers of the pellet which signifies a heterogeneous and, in some
cases, a weaker pellet.