Effect of Mill-Scale and Calcined Dolomite on High Al2O3 Sinter and Its Phase Development

Abstract Al 2 O 3 is widely regarded as a harmful gangue component in iron ore, particularly due to its impact on the melting property and reduction behavior during industrial sintering process. The current study investigated the use of low-grade iron ores with high Al 2 O 3 content in the sintering process with focus on mitigating the adverse effects of Al 2 O 3 by incorporating mill-scale and calcined dolomite. The primary phases identified in the sinters were magnetite and magnesio-ferrite. However, in case the dosage of calcined dolomite exceeded 4 wt pct, unreacted MgO particles were observed, which limited the dissolution of MgO into the magnetite matrix. This phenomenon was noticeable because it also affected the melting properties, lowering the formation of melt phase, although the peak temperature of the sinter with calcined dolomite was either lowered or maintained. The results highlight the potential of these additives to enhance sinter quality, although their additions should require careful optimization to make compromise in between phase development and selective preservation of sinter properties.