THERMAL ANALYSES OF THE SINTERING REACTIO NS OF IRON-ORES

Sintering phenomena of iron ores have been examined by applying severa l methods of thermal analyses, ie., thermogravimetry (TG), differentia l thermal analysis (DTA) and differential scanning calorimetry (DSC). Particular focus was given on the assimilation and melting behavior of major raw materials. For the reaction between fine iron ores and lime stone, heat of initial melting has a negative relation with SiO2 conte nt of the ore. Mineral state of Al2O3 component influences the melting temperature of the mixture, possibly through the stabilization of cal cium ferrite phase formed during heating. However, that of MgO compone nt does not have much effect on the melting behavior. Increase in part icle size of ore gives remarkable effect in promoting initial melting when using ores having relatively high gangue minerals at a lower tota l CaO concentration. In contrast, increase in limestone size tends to suppress initial melting at higher total CaO concentration. Reaction b etween melt and coarse iron ore particles proceeds from lower temperat ure when using pisolitic ores while ore having high iron content slowl y dissolves at higher temperature. Reactivity of dolomite with melt is larger than serpentine and promotes formation of initial melting.