CONTROL TECHNIQUE OF THE MELTING REACTION IN SINTERING PROCESS BY THEFINE PART SELECTIVE GRANULATION OF CLAYISH IRON-ORES

To control the melting reaction in sintering process by the fine part selective granulation of clayish iron ores, some studies consisted of tablet firing tests, sintering pot tests and an operation test at a co mmercial sintering machine were carried out. On the basis of these tes ts, the melting property of the bond-forming part which form the melt for coalescing pseudo-particles, and the heat supply for the melting w ere investigated. It was clarified that the melting property of the bo nd-forming part can be determined by the tablet's deforming temperatur e related to CaO and Al2O3 content. Optimum heat supply value correspo nding to the melting property of the bond-forming part was recognized for the strength of sinter (SI). As a result, the contour line of SI c ould be described on the two-dimensional map consisted of the melting property and the heat supply. Furthermore, it was possible to control the operational point on that map by the fine part selective granulati on of clayish iron ores. From the result of the operation test at a co mmercial sintering machine, the green pseudo-particles of clayish iron ores by selective granulation was strong enough to retain the segrega tion of chemical composition and heat source in the raw mix after hand ling. Also, the increase in melt formation of the sinter products was confirmed by the increase in open pore ratio and pore size. Finally, c oke consumption, permeability and reducibility of sinter were signific antly improved by the fine part selective granulation of clayish iron ores.