Effect of Core Ore Type, CaO Content and Shell Ratio of Quasi-particle on the Structural Changes of Packed Bed in the Sintering Process

Model sintering experiments were carried out in order to control the sinter cake structure under lowering slag ratio and using a large amount of limonite ore in the sinter mixture. In experiments, the influences of combined water content in core ore, and of CaO content and shell ratio of quasi-particles on the structural changes in packed bed of quasi-particles were examined by measuring compressive strength of sinter as an index. The results obtained were summarized as follows: The void fraction in packed bed of quasi-particles decreased and compressive strength increased by the melt formation during heating. Because of a negative correlation was found between the compressive strength and void fraction of sinter, it was necessary to decrease the void fraction of the sinter in order to produce the sinter having high strength. The void fraction of sinter increased by increasing in the combined water content in core ore and by decreasing in the CaO content of quasi-particle. Whereas the void fraction of sinter decreased by increasing in shell ratio of quasi-particle. However, the effect of shell ratio is small when combined water content in core ore is high. The compressive strength has been improved by mixing two types of quasi-particles, which use limonite ore and hematite ore as core ore. Therefore it is thought to be key factor to control the arrangement of CaO constituent and the mixing ratio of core ore appropriately, in order to lower the slag ratio and to use large amount of limonite ore.