niobium processing | History, Ores, Mining, & Extraction ...
Ores. Niobium occurs mostly as an oxide and has a strong geochemical coherence with tantalum. Major minerals of niobium are pyrochlore [(Na, Ca) 2 Nb 2 O 6 F] and columbite [(Fe, Mn)(Nb, Ta) 2 O 6], consisting of niobate, tantalate, iron, and manganese.Pyrochlore occurs usually in carbonatites and in pegmatite derived from alkalic rocks, commonly in association …