A method for the dissolution and purification of tantalum ore and
synthetic concentrates is described. The method preferably uses ammonium
bifluoride as the fluoride source in place of the hydrofluoric acid used
in the conventional methods. Other fluoride compounds such as NaF, KF,
and CaF.sub.2 may be used alone or in combination with ammonium
bifluoride. The tantalum concentrate and fluoride source are combined
with sulfuric acid to form a solution containing tantalum values and
impurities. The tantalum values are then separated from the impurities by
solvent extraction.