Importance of melt generation and properties in iron ore sintering

In iron ore sintering material coalescence leading to densification occurs in the flame front. Unless a certain level of material coalescence is achieved, the obtained sinter product will not have the necessary size or load-bearing strength requirements. The efficiency of this process is dependent on melt volume and flowability of the molten system at flame front. Melt volume is greatly affected by the assimilation process which depends on ore properties – composition, porosity and size. The aim of this study is to provide information on the effect of solids ratio and melt properties on coalescence. In a sinter plant these parameters alter with changing blend composition. In this study, the behaviour of tablets containing four different iron sources: porous and dense ores, sinter and a chemical reagent, was studied in two fashions: theoretically the influence of assimilation on the properties of the melt and the three-phase system was examined; by experiments with an electric furnace, material coalescence was quantified using sinter density and pore property analysis. Results show that the porous ore tablet was more deformable and had a higher densification degree compared with the dense ore tablet. The highest density was found for the tablets containing sinter and chemical grade reagents. The results indicate that increased level of porous ore or sinter of return fines may enhance coalescence in sintering.