Induration aspects of low-grade ilmenite pellets: Optimization of oxidation parameters and characterization for direct reduction application.

Induration of ilmenite pellets by oxidation is an essential step in the pelletization process since it decides the physical and metallurgical properties of the pellets. In this regard, the induration parameters such as temperature and roasting time have been optimized to obtain good quality ilmenite pellets made of concentrates obtained from low-grade ilmenite ores of Odisha, India. The oxidation temperature of 900 °C at a short roasting time of 15 min has been found suitable to achieve recommended requirements of various pellet properties such as cold compressive strength, porosity, metallization, tumble, and abrasion indices. X-ray diffraction and microstructural analysis indicate that the recrystallization of hematite in the oxidation process improves the mechanical strength of the pellets. In contrast, the formation of ferric pseudobrookite phase at 1000 °C and 1100 °C oxidation temperatures impairs the pellet strength. Unlabelled Image • The readiness of the ilmenite pellets for the reduction process was assessed through induration studies. • Different metallurgical properties were analyzed as a function of temperature and time. • Desirable pellet properties were attained at a temperature of 900 °C and a period of 15 min. • The phases changes occurred during induration were clarified using in-depth XRD, SEM, and EPMA analyses. • The oxidation mechanism of ilmenite pellets was correlated to the pellet consolidation. [ABSTRACT FROM AUTHOR]