|The most of produced tantalum is obtained from pyrochlore and tantalite-columbite concentrates, which are separated from tin smelting slag by gravitation and flotation methods as well as via electromagnetic and radiometric separation. Ta2O5 and Nb2O5 concentrations after enrichment reaches 50%. Concentrates and slags are processed until Ta2O5 or K2TaF7, from which tantalum metal is produced. Concentrates and slags are leached by hydrofluoric acid with following refining. Niobium and tantalum are separated by extraction using tributyl phosphate, cyclohexanone or hexone, or, more rare, another extragent. Tantalum hydroxide is precipitated from aquatic phase by hydrous NH3; after that it is roasted until Ta2O5 or K2TaF7 is precipitated using KF.|
In chloride way concentrate is mixed with coal or coke, briqueted after which briquettes are chloridized in shaft furnace at 700-800°C. The produced volatile tantalium and niobium pehtachloides condensate, are separated and rectificated. Ta2O5 is obtained from TaCl5, Tantalum hydroxide residuum is roasted.
In sulphate way concentrates are treated y concentrated H2SO4 or its mixture with (NH4)2SO4 at 150-300°C, the sulphates are water leached, residuum is separated, Tantalum and Niobium extracted from fluoride media, with following Ta2O5 or K2TaF7 extraction.
Tantalum metal is produced from K2TaF7-Ta2O5-KF-KCl fusion by sodium thermal reduction.
|A sol of tantalum has been prepared by sparking tantalum electrodes immersed in isobutyl alcohol using an induction coil. The sol appears brownish-black by transmitted light and black by reflected light; it keeps only for one to two weeks|