The diverse physicochemical properties of various niobium-bearing minerals in the Bayan Obo deposit make it extremely challenging to concentrate niobium resources. Converting these mineral phases into a single pyrochlore structure is proposed as an outstanding strategy for enhancing niobium beneficiation efficiency. In this study, non-isothermal reaction kineticsKinetic of the fersmite-to-pyrochlore conversion were investigated to identify the rate-determining step, given that fersmite is a representative niobium-bearing mineral. Conversion rates were calculated based on the mass fractions of fersmite and pyrochlore quantified through X-ray diffraction Rietveld refinement. The results indicated that the conversion of fersmite to pyrochlore initiated at 600 °C and reached completion at 800 °C after 90 min of isothermal holding. The conversion degree increased dramatically from 640 to 720 °C, followed by stabilization with further temperatureTemperature increases. The maximum conversion rate (97.37%) was achieved at 800 °C, which represented only a 6.33% and 1.99% increase compared with samples treated at 720 °C and 760 °C, respectively. Non-isothermal kineticKinetic analysis revealed that the second-order chemical reaction model was the best fit, as demonstrated by the highest coefficient of determination. Meanwhile, the calculated apparent activation energy was 160.21 ± 13.30 kJ·mol−1. Therefore, the second-order chemical reaction model indicated that excess NaF reactant significantly promoted the fersmite-to-pyrochlore conversion.