An alkaline roasting of a coltan bearing ore from the Numbi deposit (South Kivu, the DRC) was investigated with particular focus on the extraction kinetics of Ta and Nb. Isothermal roasting experiments were carried out to study the effects from KOH to ore mass ratio, particle size and roasting temperature on the degree of Ta and Nb recoveries. The roasting efficiency was found to be affected by all the parameters being studied with their optimal values being found as following: particle size range +75–45 µm, KOH to ore ratio 3/1, roasting temperature 550 °C and roasting duration of 1 h. Under these conditions, 80% of Ta and 87% of Nb were recovered from the ore. The kinetic data analysis by different kinetic models indicated that the caustic potash roasting of the Numbi coltan ore is governed by a chemical reaction at particle surface. The apparent activation energies for Ta and Nb were estimated as 40.9 and 46.1 $\mathrm{k}\mathrm{J}.{\mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$ respectively. The obtained results demonstrated that it is possible to bring Ta and Nb into solution without using hydrofluoric acid and deliver a pregnant leach solution (PLS) suitable for downstream treatment.

研究了从Numbi矿床（South Kivu，DRC）中的or钽铁矿石的碱性焙烧，尤其着眼于Ta和Nb的萃取动力学。进行了等温焙烧实验，研究了KOH与矿石质量比，粒度和焙烧温度对Ta和Nb回收率的影响。发现焙烧效率受所有正在研究的参数的影响，其最佳值如下：粒度范围+ 75–45 µm，KOH与矿石的比例为3/1，焙烧温度为550°C，焙烧持续时间为1 H。在这些条件下，从矿石中回收了80％的Ta和87％的Nb。通过不同动力学模型进行的动力学数据分析表明，Numbi tan钽铁矿石的苛性钾焙烧受颗粒表面化学反应控制。$\mathrm{ķ}\mathrm{Ĵ}。{\mathrm{米}\mathrm{Ø}\mathrm{升}}^{--\mathrm{1个}}$分别。获得的结果表明，可以在不使用氢氟酸的情况下将Ta和Nb引入溶液中，并提供适合下游处理的母体浸出溶液（PLS）。