Characteristics of nano-reactor and phenomena during mechanical milling of hematite-graphite mixture

Abstract

The mechanical milling of hematite and graphite mixture could accelerate the reaction rate extremely, when the mixture after milling was heated up under inert atmosphere. In the previous study, the authors have indicated not only the high reaction rate but also the low starting temperature of the reaction. These phenomena can be understood through the view point of the nano-reactor and the active complex. The nano-reactor was defined in this study through the observation of the milling products by TEM and FE-SEM. The important characteristic of nano-reactor was proposed. Moreover, the phenomena such as the reduction reaction, the phase transformation(formation of an active complex) and the crystalline size degradation occurring in the course of the milling were examined. It was found that the milling of mixture gave a different phenomenon from the single hematite or graphite milling. Furthermore, the atmosphere during the milling affected on the reactivity of the milling product. The existence of oxygen caused the reoxidation of the reduction product which resulted in the different crystalline size after milling.