Effect of drying treatment after granulating sinter raw materials on flame front speed and sintering yield

Abstract

For increase of sinter productivity, it is important to design sinter mixture granulation. Moisture is indispensable for granulation as a binder between raw material particles. Once granulation is completed, moisture is dispensable during sintering because moisture vaporization is endothermic reaction. Based on the above-mentioned view, a process of drying the granules after granulation with high moisture examined for sintering productivity by use of sinter pot test. The main results obtained are described as follows: (1) Drying in conjunction with high moisture granulation is effective to increase flame front speed with maintaining sintering yield; (2) Increasing flame front speed is due to shorten the time to evaporate moisture in the wet zone of sintering packed bed in addition to increasing permeability of sintering packed bed. This effect is also evaluated and proved based on calculation of moisture transition in and out of sintering packed bed; (3) Maintaining sintering yield is due to higher heat generation in sintering packed bed caused by higher coke combustion efficiency in addition to lower moisture concentration of sinter mixture. (4) Collapse of granules in case of drying after granulation is avoided till the critical moisture, that is defined as the one left in the mix after higher moisture granulation makes granules to keep shape easy due to higher moisture quantity on the surface of granules.