Comparative Beneficiation Study of Gyel Columbite Ore Using Double Stage (Magnetic-to-Magnetic and Magnetic-to-Gravity) Separation Techniques

Abstract

The comparative beneficiation study of Gyel columbite ore using double stage (magnetic-to-magnetic and magnetic-to-gravity), located in the vicinity of Gyel village in Jos South Local Government Area of Plateau State to metallurgical grade was carried out. The ore sample was sourced from 20 different pits each 1.5 × 1.5 × 2 meters deep, 50 meter apart covering a land of 50 hectares. The samples from the 20 pits were crushed, pulverized and homogenized. 200 kg of the homogenized ore sample was used for the experiment and laboratory works. Chemical characterization of the ore sample was carried out using energy dispersive X-ray fluorescence spectrometer (ED-XFR). Single and double stage concentration tests using magnetic and gravity methods were carried out respectively. The results of the chemical analysis of ore sample reveal that, Pit 1 contains 12.26% Nb 2 O 5 , 21.6% Fe 2 O 3 , 36.1% SiO 2 ; Pit 20 contains 4.78% Nb 2 O 5 , 19.34% Fe 2 O 3 , 23.96% SiO 2 and the homogenized sample contains 6.71% Nb 2 O 5 , 23.1% Fe 2 O 3 and 27.0% SiO 2 averagely. The liberation study reveals that the niobium of ore can be liberated over a range of sieve size fractions of -355 + 63 μm for the coarse and -63 + 45 μm for the fine particle size fractions. On the basis of this, sieve size fractions of -1400 + 355 μm (as coarse size), -355 + 90 μm (as medium size) and -90 + 45 μm (as fine size) were used for the concentration tests. The concentration test using the double stage processes revealed that the air-floatation followed by rapid magnetic method produced a concentrate with the highest percent assay of 54.48% Nb 2 O 5 with a recovery of 96.53% followed by the rapid-to-rapid magnetic method which produced a concentrate assaying 52.12% Nb 2 O 5 with a recovery of 86.96%. These results meet and surpass the 50% Nb 2 O 5 stipulated as the acceptable metallurgical grade concentrate for niobium metal production in the literature.