<p>The performance of iron ore pellets was influenced by gangue mineral interactions and alkali metal migration during the oxidation and reduction processes. A novel synergistic strategy was proposed to optimize pellet properties by regulating the liquid phase content coupled with MgO addition. The effects of SiO₂ and MgO contents on liquid phase generation, pellet microstructure, compressive strength, reduction swelling index (RSI), and reduction index (RI) were systematically investigated. The results showed that the&#xa0;increasing SiO₂ content significantly enhanced liquid phase formation, thereby improving compressive strength and reducing RSI, but lowering RI. MgO promoted the formation of Mg_<i>x</i>Fe_3–<i>x</i>O₄ during oxidation, increasing porosity and enhancing RI while slightly compromising mechanical strength. In addition, Mg_<i>x</i>Fe_3–<i>x</i>O₄ reduced the expansion during the initial reduction stage (Fe₂O₃ → Fe₃O₄). Optimal performance was achieved when the liquid phase content in the roasted pellet was maintained at 11%–13% and MgO at 2.0%–2.6%, with compressive strength exceeding 2500 N, RSI below 20%, and RI above 64%. In addition, doubling the liquid phase content reduced the concentration of alkali metals diffused into the iron oxide lattice by approximately 50%, mitigating the localized precipitation of metallic iron whiskers during the final reduction stage (Fe_<i>x</i>O → Fe). Alkali metal doped into iron oxides during oxidation had a more pronounced effect on swelling behavior than the reduction process. These findings offered practical insights into high-performance pellet production under industrial conditions.</p>