Heliyon (Jan 2024)
Hydrometallurgical assessment of oxides of Nb, Ta, Th and U from Ethiopian tantalite ore
Abstract
Tantalite ore is the main source of the metals niobium (Nb) and tantalum (Ta). Today, the needs for these economic and irreplaceable Nb, and Ta metals are becoming imperative for the technological world, to meet the demand, a lot of research is needed to ore reserves, extraction methodology and simplified refining processes should be in plethora. This study focuses on the Ethiopian tantalite ore located south of the Neoproterozoic Adola belt of the rare element Kenticha pegmatite deposit (global source of tantalite). Successive beneficiation of pegmatite ore results in a highest dissolution of 60.83 wt% of Ta2O5 with 4.58 wt% of Nb2O5 including the removal of U, Th, Ti, Fe and Si, resulting in a percentage low weight, which allows transporting ore concentrates. The concentrated ore is leached with a mixture of binary acids HF and H2SO4 with 6:1 ratio at temperatures from 100 to 400 °C. The filtered solution was extracted with MIBK then, precipitated with ammonium solution. The hydrometallurgy of Nb and Ta oxides is affected by leaching temperature and the presence of radioactive oxides of U and Th. Elemental analysis and surface topography were studied using SEM/EDS, revealing the highest percentage composition of Nb and Ta oxides at 200 °C of leaching temperature. Comparatively, the compositions of U and Th showed higher amounts at the leaching temperatures of 150 and 200 °C, and when the temperature reached about 350 and 400 °C, the percentage composition of U and Th became very low, the economic metals Nb and Ta were completely leached. The stability of the precipitated samples was analyzed using TGA-DTA and found to be thermally stable, and not contain significant moisture at each temperature studied. Studies for recovery of Ta, Nb, U and Th from Kenticha tantalite are required.
