Study on the Effects of Mg–Si Gangue Compositions within Magnetite on Iron Oxide Crystallization during Pellet Roasting

This article investigates the consolidation performance of high‐magnesium content pellets under varying roast temperatures and Mg–Si elemental contents. The study reveals that as the proportion of high‐Mg–Si ore increases, the strength of preheated pellets decreases from 546 to 470 N at a constant preheating temperature. The rise in magnesium and silicon phases diminishes the oxidation degree of the pellets, requiring a higher sintering temperature to achieve optimal consolidation. The research indicates that at 1200 °C pellets exhibit the highest average compressive strength with the best level of oxidation and secondary crystallization. However, over‐roasting leads to a reduction in pellet strength due to excessive liquid phase interference at 1250 °C. When the high‐Mg–Si raw material proportion is 50 wt%, the pellets with the highest compressive strength of 2843 N are yielded at the sintering temperature of 1200 °C and preheating temperature of 850 °C, which is attributed to the high oxidation, secondary crystallization of magnetite, and the MgO content facilitating the formation of CaO·Fe 2 O 3 liquid phase, resulting in the best pellet consolidation strength.