Extraction of niobium and tantalum from ferrocolumbite by hydrofluoric acid pressure leaching

• Published in: Hydrometallurgy Vol. 156; pp. 17 - 20
• Main Authors: Rodriguez, Mario H., Rosales, Gustavo D., Pinna, Eliana G., Suarez, Daniela S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-07-2015
• Subjects: Acid leaching; Ferrocolumbite; Hydrofluoric acid; Hydrometallurgy; Leaching; Niobium; Pressure leaching; Reaction time; Tantalum; X-ray diffraction; Ferrocolumbite; Tantalum; Pressure leaching; Niobium
• ISSN: 0304-386X; 1879-1158
• DOI: 10.1016/j.hydromet.2015.05.006

Pressure acid leaching was used to extract niobium and tantalum from a ferrocolumbite ore. The leaching was carried out in a pressure reactor using hydrofluoric acid as leachant. Various parameters, such as temperature, reaction time, HF concentration, stirring speed, particle size and solid-to-liquid ratio in the leaching process, were optimized. The reactants and products were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and specific surface area (BET). Experimental results showed that the maximum extraction of Nb and Ta, 90 and 80% respectively, it was achieved at an HF concentration of 9% v/v, reaction temperature of 220°C, particle size of −45μm, solid-to-liquid ratio of 1.82% w/v and reaction time of 80min. Crystalline structures, different from those originally present in the ore, were not detected by XRD analysis of the leaching residues.
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•A HF leaching process was used to extract Nb and Ta from ferrocolumbite.•Temperature, reaction time and HF concentration affect Nb and Ta extraction.•The extraction efficiency of Nb and Ta reached 90% under the optimal conditions.