Our products Tantalum

Tantalum is one of the main metals to be exploited, at both the Penouta Mine and in the pegmatitc dikes of the Alberta II Investigation Permit, although the research to characterize the metal in dikes is still being conducted.

In the case of the Penouta Mine, tantalum is mainly found in the following mineral species.

  • Columbite Group Minerals [(Fe,Mn)(Ta,Nb)2O6], where variable Fe-Mn and Ta-Nb substitutions led to the formation of the different minerals of the series.
  • Pyrochlore Group Minerals (Pyrochlore subgroup [(Na,Ca)2Nb2O6(O,OH,F)]).
  • Ixiolite [(Ta,Nb,Sn,Mn,Fe)O2]

Columbite-tantalite and microlite are the most common minerals in nature. They occur in rare metal pegmatites containing Ta, Be and Li, as well as in highly evolved rare metal albite leucogranites, which are commonly Sn-enriched. This is the case for the pegmatites found in the Alberta II Research Permit and the low phosphorous albite leucogranite of Penouta, respectively.

Compositional and size variations in the columbo-tantalites

Columbite-tantalite crystals are commonly zoned due to the lower Nb solubility compared to Ta in the peraluminous rocks where they generally are formed, so that Nb-rich species crystallize first (core of crystals) and after that the Ta-rich species (border of crystals) There is also a variation in the Fe and Mn contents, firstly crystallizing the Fe-rich species followed by the Mn-rich ones.

The different solubility of Nb and Ta in the granitic melts favors the crystallization of columbite towards the bottom of the granites, as occurs in Penouta, whereas tantalite forms to the apical zones. This fact can be observed by the different color of these minerals when observed at the petrographic microscope: columbite shows reddish color while tantalite is darker or even black.

In the Penouta Mine project, we have also observed a variation in the grain size of the Cb-Ta crystals in the mineralized granite, the larger crystals occurring towards the apical zone. This can be due to a strong concentration of rare metals (particularly Ta) in these areas, and/or the larger crystals occurring towards the apical zone, growing coarser crystals.

Ta Applications

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