Abstract
Traditional extraction methods for niobium (Nb) and tantalum (Ta) rely heavily on hydrofluoric acid (HF), which poses significant environmental and safety risks. This study investigates an eco-friendly alkali fusion and water-leaching process as a cleaner alternative. Using a pyrochlore-microlite-bearing intermediate concentrate, alkali fusion with potassium hydroxide at 700 °C, followed by water leaching, achieved high extraction efficiencies of 86.4% for Nb and 91.4% for Ta. The process demonstrated excellent selectivity against major impurities, with minimal extraction of iron (6.3%) and calcium (1.2%), while aluminum, sodium, and titanium were solubilized.