Utilization of High-Alumina Iron Ore in Pellet Making Through Process Optimization

The demand for pellets in blast furnaces has recently increased because of their uniform shape and size, controlled chemistry, iron-enriched feed, high strength, and quality consistency. To meet this demand, low- and medium-grade iron ore fines with alumina (> 3.5 wt%) must be used for pelletization because of the limited availability of high-grade ore. The alumina present in the ore has an adverse effect on the pellet properties because of its refractory nature. Therefore, a study was conducted to optimize the firing temperature and chemistry of the feed blend to produce pellets with good pellet properties. Firing temperature (1280 °C, 1300 °C, and 1320 °C), carbon (1 and 1.2%) in the form of coke fines, and MgO (0.60 and 0.80%) in the form of dolomite were used to optimize the pellet-making process for high-alumina iron ore fines. The best result was obtained for feed blend with 1.2% carbon and 0.80% MgO fired at 1300 °C to produce pellets of cold compressive strength more than 300 kg/pellet, reduction degradation index (− 6.33 mm) near 7%, and porosity near 20%.