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In the ironmaking processes via the carbothermic reduction with the tall-bed reactor, the composite pellets are rapidly reduced to highly metallized direct reduced iron (DRI) with high productivity under high temperature. Without coke making and ore sintering process, carbothermic reduction are not only help broaden the selection of raw materials but an environmentally friendly approach for the ironmaking process. In this study, experiments were conducted for iron ore-coal composite pellets under four heating rates. During the reduction, the reaction was quenched at different temperatures by quickly moving the specimens to room temperature. After the experiments, we performed phase analysis by X-ray diffraction, chemical composition analysis by wet method, and microstructure observation and element distribution analysis by scanning electron microscopy with energy dispersive spectrum. The pellet morphology during the experiments was also recorded. The pellets under fast heating rates (80°C/min and 40°C/min) collapsed over 1 300°C. The pellets under the slow heating rate (20°C/min) maintained their spherical morphology until 1 400°C. We found that the formation and melting of fayalite (2FeO-SiO 2 or Fe 2 SiO 4 ) played a key role in the collapsing behavior of pellets, which can be classified into three different stages, (a) between 1 000°C and 1 200°C, a large amount of fayalite compound (melting point at 1 178°C) was formed. (b) above 1 178°C, the fayalite compound started to melt and became a liquid phase. (c) between 1 178°C and 1 400°C, the pellets lost their strength, and collapsed due to the excess amount of liquid phase present.