Evaluation and optimisation of impact of iron ore microfines (<150 µm) in sintering process

The degradation of iron ores, mechanised mining, and advanced beneficiation technique have increased microfines <150 µm within iron ore. This study examines the influence of microfines on sinter properties through laboratory pot trials, where microfines content within the iron ore mix was increased from 0% to 30%, raising the total raw mix microfines fraction from 21% to 48.2%. The results showed longer sintering times, reduced productivity from 2.0 to 1.7 t/m ² /hr, lower yield from 87% to 84.5%, decreased strength from 72% to 64%. To mitigate these effects, optimisation was carried out in two steps: first, increasing calcined lime from 2.6% to 2.95%, resulting in improved productivity and reduced sintering time, with decreased strength. Second, raising fuel from 3.9% to 4.5%, resulting in enhanced sintering time, productivity and strength.