Abstract: The leaching kinetics of niobium from a low-gr~te niobium-tantalum ore by concentrated KOH
solution under atmospheric pressure has been studied. Significant effects of reaction
temperature, KOH concentration,stirring speed, particle size and mass ratio of alkali-to-
ore on the dissolution rate of niobiumwere examined. The experimental data of the leaching
rates and the observed effects of the relevant operating variables were well interpreted
with a shrinking core model under diffusion control. By using the Arrhenius expression, the
apparent activation energy for the dissolution of niobium was evaluated. Finally, on the
base of the shrinking core model, the rate equation was established.

Key words: clean process, leaching, kinetics, KOH, niobium-tantalum ore, diffusion control

摘要： The leaching kinetics of niobium from a low-gr~te niobium-tantalum ore by concentrated KOH
solution under atmospheric pressure has been studied. Significant effects of reaction
temperature, KOH concentration,stirring speed, particle size and mass ratio of alkali-to-
ore on the dissolution rate of niobiumwere examined. The experimental data of the leaching
rates and the observed effects of the relevant operating variables were well interpreted
with a shrinking core model under diffusion control. By using the Arrhenius expression, the
apparent activation energy for the dissolution of niobium was evaluated. Finally, on the
base of the shrinking core model, the rate equation was established.

关键词: 铌;动力学;过滤技术;钽;KOH;扩散控制;温度