Mansheng Chu

Abstract:

Faced with the raw material shortage of iron and steel industry, it is necessary to improve the use of lean ore such as carbonate iron ore. Carbonate iron ore is one of the main potential sources of iron with a large reserve in Liaoning and Shanxi provinces in China. Due to its significance and complex component, a new beneficiation process of peroxidation-reduction process for carbonate iron ore comprehensive utilization was proposed in the work. During the process, carbonate iron ore was completely oxidized into Fe2O3 first to improve ore grade and uniform ore composition and then reduced into Fe3O4 or ¦A-Fe2O3 which both had strong magnetism to separation. This work was focused on the oxidation part of the new process. Based on the fundamental characteristics of carbonate iron ore, the effects of roasting temperature and roasting time on the oxidation degree and weight loss rate were investigated by the single factor experiment. Besides, through the XRD and SEM analyses, the microstructure change together with phase transformation during oxidation were studied. It was shown that with the increased roasting temperature and time, the oxidation degree could rapidly increase to 99% while the weight loss rate increased to 14.67% and 12.00% respectively. The phase transformation during oxidation was proceeded as followed: FeCO3 ¡u Fe3O4 ¡u ¦A-Fe2O3 ¡u ¦A-Fe2O3 and the optimal roasting parameters to make carbonate iron ore oxidize completely included a temperature of 500¡æ and for a period of time of 30 min.