Preparation of Nickel-Bearing Chromite Overburden Pellets Suitable for DRI Production

Due to the increased demand and limited supply of nickel, the chromite overburden found in Sukinda Valley, Odisha, can be effectively utilized. This study proposes an alternative method for producing high-quality indurated pellets suitable for direct reduced iron production, which can be further smelted to obtain nickel-based alloys in an energy-efficient manner. Excellent quality pellets from low-grade ferruginous chromite overburden were obtained by optimizing various pelletization parameters, such as basicity values, induration temperatures, and duration. The optimal conditions for producing these pellets were found to be a basicity value of 1.0, an induration temperature of 1300 °C, and an induration time of 10 min. These pellets exhibited excellent metallurgical properties and can be used as a burden for subsequent DRI production. The experimental results were further corroborated by various characterization studies, including X-ray diffraction and scanning electron microscopy coupled with energy dispersion spectroscopy analyses. The study found that the recrystallization of hematite phases during the induration process improved the mechanical strength and various other properties of pellets. However, slightly higher basicity and induration parameters impaired pellet consolidation by creating cracks and forming low-melting slag phases.