Evaluation of melting characteristics of fine iron ores by the tablet sintering test

Characteristics of iron ores have influence upon sintering operation and sinter quality. Mineralogical properties of fine iron ores affect significantly the melting behavior in the sintering process. In this study, in order to estimate the macroscopic melting behavior which is directly linked to the coalescing of granules and the formation of pore network in the sintering process, tablets consisted of the mixture of fine iron ores and limestone were prepared. Sintering tests were carried out using the tablets, and the deforming behavior of the tablets was quantified as the deforming temperature. The deforming temperature was strongly affected by gangue minerals in iron ores, mainly because of the rising of peritectic temperature of quaternary calcium ferrite by the dissolution of clay into the calcium ferrite melt. The deforming temperature of iron ore mixture depended on that of each iron ore and its mixing ratio. The influence of MgO sources such as serpentine and Ni slag on the deforming temperature was examined. The means to control the melting behavior in the sintering process by the granule design of raw mixtures was discussed.