摘要 |
<p>Raw materials containing tantalum or niobium are treated to obtain aqueous solutions containing fluoroacid complexes of niobium or tantalum. These solutions are decomposed by pyrolysis and calcined to obtain pure oxides of niobium or tantalum. The hydrofluoric acid separated during pyrohydrolysis is recovered and reused. A niobium or tantalum-free raffinate solution obtained, on extraction, with the above aqueous solutions contains dissolved metalloids which are recovered as oxides which are deposable waste products.</p> |