To optimize the process and improve the degree of reduction, a two-stage experiment wasdesigned. It was carried out in a micro-fluidized bed. It is operated as a differentialreactor to ensure every particle in the micro-fluidized bed is at equal temperature,concentration and residence time. The experiment used iron ore powder from Yangdi. Thereducing gas and temperature in the pre-reduction stage were, respectively, pure CO and625 °C. In the final reduction stage, the temperature and reducing gas were, respectively,800 °C and pure CO. The residence time was between 10 min and 60 min. In addition to theexperiment, a microscopic technique was also carried out. The test shows a significantinfluence of the temperature and residence time of the two-step experiment on the finalreduction degree.
