The major Raw Materials required for production of Pellets by the Grate chain technology are graded Iron Ore fines and Bentonite. Coke/H.S.D./L.D.O. is being used as a Fuel.
The quality requirement of Sized ore for sponge iron production can be classified into:-
1) Physical requirements :-
The optimum tumbler strength of the ore should be < 70 percent minimum, Depending on the reducibility, closely calibrated ores in the size range of 0 to 5 mm generally used.
2) Metallurgical requirements :-
The ore should be highly reducible, thermally stable and have a low tendency for sticking and disintegration during heating and reduction.
3) Chemical requirements :-
Apart from the removal of oxygen, no other major chemical change takes place in direct reduction. The gangue material in sponge iron, originating from Iron Ore, namely, silica and alumina and the sulphur and phosphorous contents adversely affect the economics in subsequent steel making operation. Therefore, the ore should be high in iron content and low in gangue.