<p>Ilmenite is a crucial raw material for the production of metallic titanium (Ti) and Ti-based products, with hydrogen reduction being a promising method for achieving green and low-carbon ilmenite production. However, such process is limited by low rate of hydrogen reduction of ilmenite and challenges in separation of Ti and Fe. This study systematically investigated the mechanism of action of Na₂O as an additive in the hydrogen reduction of ilmenite, revealing its critical role in accelerating reaction kinetics and promoting the growth of metallic iron particles. Theoretical analysis indicated that the addition of Na₂O reduced the reduction temperature of ilmenite and the melting point of the slag. Experimental results demonstrated that a 6&#xa0;wt% Na₂O addition significantly improved the hydrogen reduction rate of ilmenite and facilitated migration and agglomeration of reduced iron particles, increasing the average size of metallic iron particles from 12 to 36&#xa0;μm. However, when 9&#xa0;wt% Na₂O was added at 1200&#xa0;°C, a notable reaction occurred between metallic Fe and sodium titanate, leading to a decreased metallization rate. This study systematically elucidated the mechanism of Na₂O’s role in enhancing ilmenite hydrogen reduction, providing a theoretical basis for understanding the function of sodium ions in various sodium-based additives, and thus advancing the green and efficient utilization of ilmenite resources.</p> Graphical Abstract <p></p>