Processing of Blue Dust from Daitari Iron Ore Deposit, Singbhum Craton, Odisha, for Optimum Utilisation

Abstract

Blue dust, a naturally occurring high-grade iron ore from the Daitari iron ore deposit, Odisha, presents a utilisation challenge due to its fine nature and poor cohesiveness, rendering it unsuitable for direct blast furnace use. This study evaluates the efficacy of pelletization as an agglomeration route using bentonite, limestone, and coke fines as additives. Green pellets prepared from − 75 µm feed with 1% bentonite exhibited superior mechanical properties, including green compressive strength (GCS) and drop resistance. Subsequent induration at 1300 °C yielded pellets with enhanced cold crushing strength (CCS) (~ 290 kg/pellet) and controlled porosity (~ 22%). XRD and microscopy revealed recrystallisation of hematite and formation of calcium ferrite phases, contributing to thermal stability and structural integrity. The results establish pelletization as a viable technique for transforming fine-grade blue dust as blast furnace feed, thereby facilitating improved ore utilisation in iron and steel making.