Characterisation of Columbite-Tantalite (Coltan) Ore from Nasarawa State for Niobium and Tantalum Recovery

This study characterises columbite-tantalite (coltan) ore from deposit sites in Nasarawa State, North Central Nigeria, to assess the ore's suitability for niobium and tantalum recovery. Nigeria possesses significant coltan reserves, particularly in the basement complex states of the North Central zone, and coltan is a critical material for electronics, superalloys, and superconducting applications. Ore samples are collected from three mining localities in Akwanga and Lafia Local Government Areas. Mineralogical characterisation is performed by XRD, XRF chemical analysis, SEM-EDX, and electron probe microanalysis (EPMA). Heavy mineral concentration is performed by gravity separation and Frantz isodynamic magnetic separation. Hydrometallurgical dissolution experiments using HF-H2SO4 digestion and NaOH fusion are conducted to determine extraction efficiency for niobium and tantalum. Solvent extraction using MIBK and TBP is tested for selective Nb/Ta separation from the pregnant leach solution. Results confirm columbite-tantalite as the dominant ore mineral, with Ta2O5 and Nb2O5 contents averaging 18 and 54 percent respectively in beneficiated concentrate. Combined gravity and magnetic separation achieves a concentrate grade of 62 percent (Nb2O5 + Ta2O5). Hydrometallurgical extraction efficiency exceeds 90 percent. The study demonstrates a viable processing pathway for Nasarawa State coltan ore and recommends pilot hydrometallurgical processing studies. Keywords: coltan, niobium, tantalum, ore characterisation, Nasarawa State.