Decomposition of the Kenticha mangano-tantalite ore by HF/H2SO4 and KOH fusion
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Jimma Institute of Technolgy, Jimma University
College of Natural and Computational Science, Mekelle University
Western Australian School of Mines, Curtin University
School of Chemical and Bio Engineering, Addis Ababa University
Research and Development Directorate, Federal Democratic Republic of Ethiopia, Ministry of Mines, Petroleum and Natural Gas
Bogale Tadesse   

Western Australian School of Mines, Curtin University, Egan St, 6433 Kalgoorlie, Australia
Physicochem. Probl. Miner. Process. 2018;54(2):406–414
In this study, the decomposition behavior of Ta and Nb from the mangano-tantalite ore was investigated using HF/H2SO4 mixture and KOH fusion. The effects of reaction time, decomposition temperature, acid and alkaline concentrations, and particle size on the dissolution process were examined. Higher decomposition rates were achieved at 6:2 mol/dm3 ratio of HF and H2SO4, and with the addition of 10 g KOH in the alkali fusion step. In addition, similar trends in decomposition rates between two agents (HF/H2SO4 and KOH) and comparable dissolution performances were observed. The increase in the decomposition temperature initially increased the decomposition rate of mangano-tantalite for the two systems considered in this study. However, no significant change in the leaching rate of Ta and Nb was observed beyond 50 °C for the HF/H2SO4 system and above 400 °C when using the KOH fusion process. The elemental and compositional analyses of the leached residues using XRF, XRD, and FT-IR spectroscopy indicated that the acid (mixture of HF and H2SO4) decomposition resulted in slightly better dissolution performance for Ta compared with the alkaline fusion method. Overall, the results indicated that KOH can be a suitable alternative decomposition agent to the volatile, corrosive and toxic HF in the hydrometallurgical processing of tantalite ores.
AGULYANSKY, A., 2004. Tantalum and niobium fluoride compounds, Elsevier, Amsterdam, Chap. 4.
BERHE, G.G., ALBERTO, V.R., YIMAM, A., WOLDETINSAE, G., TADESSE, B., 2017, Alternative beneficiation of tantalite and removal of radioactive oxides from Ethiopian Kenticha pegmatite–spodumene ores, Int. J. Min. Met. Mater. 24, 727–735.
BOSE, D.K., GUPTA, C.K., 2001, Extractive metallurgy of tantalum, Min. Pro. Ext. Rev. 22, 389-412.
CERNY, P., ERCIT, T.S., 2005, The classification of granitic pegmatites revisited, Can. Mineral. 43, 2005-2026.
EL-HAZEK, M.N., AMER, T.E., ABU EL-AZM, M.G., ISSA, R.M., EL-HADY, S.M., 2012, Liquid–liquid extraction of tantalum and niobium by octanol from sulfate leach liquor, Arabian J. Chem. 5, 31-39.
EL-HUSSAINI, O.M., MAHDY, M.A., 2010, Extraction of Niobium and Tantalum from Nitrate and Sulfate Media by Using MIBK, Min. Pro. Ext. Rev. 22, 633-650.
GUPTA, C. K., SURI, A.K., 1993. Extractive Metallurgy of Niobium, CRC Press, Florida.
JEWELL, A., KIMBALL, S.M., 2015. Mineral commodity summaries 2015: U.S. Geological Survey, 196 p.,
KIM, E., KIM, S., MOON, D., KOH, S., 2013, Fractionation and rare-element mineralization of Kenticha pegmatite, Southern Ethiopia, Econ. Environ. Geol. 46, 375-390.
KUSTER, D., ROMER, R.L., TOLESSA, D., ZERIHUN, D., BHEEMALINGESWARA, K., MELCHER, F., OBERTHÜR, T., 2009, The Kenticha rare-element pegmatite, Ethiopia: internal differentiation, U-Pb age and Ta mineralization, Miner. Deposita. 44, 723-750.
NETE, M., PURCELL, W., NEL, J.T., 2014, Separation and isolation of tantalum and niobium from tantalite using solvent extraction and ion exchange, Hydrometallurgy. 149, 31-40.
RODRIGUEZ, M.H., ROSALES, G.D., PINNA, E.G., SUAREZ, D.S., 2015, Extraction of niobium and tantalum from ferrocolumbite by hydrofluoric acid pressure leaching, Hydrometallurgy. 156, 17-20.
TADESSE, S., ZERIHUN, D., 1996, Composition, fractionation trend and zoning accretion of the columbite-tantalite group of minerals in the Kenticha rare metal field (Adola, Southern Ethiopia), J. Afr. Earth Sci., 23, 411-431.
WANG, X., SHI-LI, Z., HONG-BIN, X., YI, Z., 2010, Dissolution behaviors of Ta2O5, Nb2O5 and their mixture in KOH and H2O system, Trans. Nonferrous Met. Soc. China. 20, 2006-2011.
WANG, X., ZHENG, S., XU, H., ZHANG, Y., 2009, Leaching of niobium and tantalum from a low-grade ore using a KOH roast–water leach system, Hydrometallurgy. 98, 219-223.
ZERIHUN, D., GARBARINO, C., VALERA, R., 1995, Granite pegmatite system in Kenticha (Adola, Sidamo, Ethiopia) rare metal pegmatite belt: petrochemistry, regional pegmatite zoning and classification, SINET Ethiopian J. Sci. 8, 119-148.
ZHOU, H., ZHENG, S., ZHANG, Y., Yi, D., 2005, A kinetic study of the leaching of a low-grade niobium-tantalum ore by concentrated KOH solution, Hydrometallurgy. 80, 170-178.
ZHU, Z., CHENG, C.Y., 2011, Solvent extraction technology for the separation and purification of niobium and tantalum: a review, Hydrometallurgy. 107, 1-12.