Strength and granuometry
are the two important physical requirements. The ore should be hard
and possess high strength. The optimum tumbler strength
of the ore shuold be 80 percent minimum. Depending on
the reducibility, closely calibrated ores in the size
range of 5 to18 mm are generally used.
(b)
METALLURGICAL REQUIREMENT
The ore should
be highly reducible, thermally stable and have a low tendancy for
sticking and disintegration during heating and reduction.