Effect of phase composition on sulfuric acid leaching of tantalum-containing alloys

Phase composition of iron-based tantalum-niobium alloys (Ta 2-5, Nb 3-6, Si up to 12, C 1.4-2.4%) was studied. The kinetics of leaching of ferroalloys with H2SO4 aqueous solutions and with mixtures of sulfuric and hydrofluoric acids was considered. The conditions of hydrochemical treatment of the alloys, which make it possible to concentrate niobium and tantalum in the solid residue through dissolution of up to 94% of Fe, 90% of Mn, and 70% of Si, were found.