• Pre-reduction sintering removes 58.02% of K and 30.68% of Na from raw mixtures while improving yield to 74.40% and tumbler index to 68.69%.
• Flue gas recirculation further boosts alkali removal to 74.11% for K and 32.92% for Na while recycling CO.
• The process reduces NOx and SO2 emissions and increases CO content in flue gas, contributing to lower overall emissions.
• Pre-reduced sinter consists mainly of magnetite, wustite, and small amounts of metallic iron, with minimal silicate glass phase, enabling simultaneous alkali removal and emission reduction.