THE RELATION BETWEEN FINE RATIO AND PARTICLE-SIZE OF SINTER PRODUCT IN SINTER CAKE SIZING PROCESS

The breakage process of sinter cake was investigated to find the most efficient sizing method that minimizes the -5 mm fraction in crushed cakes. Sinter cakes with various initial sizes were crushed with a jaw-crusher, shatter and tumble testers to compare the -5 mm fines generation processes. The results showed that the dominant factor that decides the amount of -5 mm fines is the final size of the crushed +5 mm products. Under a specific crushing mode, the -5 mm fines mass is decided by the mean particle size of the residual +5 mm products, independent of the cake strength. The second dominant factor is the crushing mode and the jaw-crusher yields the least -5 mm fines mass among the three crushing modes. Thus the most efficient process is to crush sinter cake with jaw-crushers to a size which is small enough as a feed for blast furnaces. The reason why a jaw-crusher yields the least -5 mm fines mass was considered to be due to a volume breakage included in this mode where the applied energy is used for the size reduction, while the other breakage mode, surface breakage is not preferable to crush sinter cakes because the size reduction takes place by surface grinding that leads to a high -5 mm fines mass.