Desliming process of kuru columbite (Plateau state) using scrubbing method towards niobium pentoxide recovery

Abstract

The presence of niobium in nature is associated with pegmatite in the form of columbite which necessitates its recovery process from the crude. Kuru Columbite Ore was sourced from ten different pits properly mixed to obtain homogenization and 20 kg was sampled out using the random sampling method, it was ground using the Denver milling machine and prepared towards characterization followed by desliming process by repeated scrubbing technique. Chemical characterization of the crude sample was carried out using Energy Dispersive X-ray Fluorescence Spectrometer (ED-XRF). Mineralogical analysis was carried out using X-ray Diffractometer (XRD) and Scanning Electron Microscope equipped with Energy Dispersive Spectrometer (SEM-EDS). 100 g of the crude sample using the cone and quartering method was sampled out for the particle size analysis and 1000 g each of sieve fractions –710+500 µm, –500+355 µm, –355+250 µm, –250+180 µm, and –180+125 µm was used for the scrubbing process. ED-XRF analysis revealed that the crude sample contains 11.4% Nb2O5, 39% SiO2, 6.56% Fe2O3, 0.34% TiO2 and other compound in trace forms. Mineralogical analysis of the Kuru columbite revealed the present of niobium oxide, iron tantalum, with other associated minerals. SEM images revealed that the ore contains coarse grains of niobium pentoxide which are disperse within the matrix of the ore, this implies that it requires less energy to liberate niobium pentoxide within the matrix of its ore and are evenly dispersed. The EDS of these microstructures revealed the presence of O, Mg, Al, Si, and Fe. The particle size analysis revealed the liberation size to be -250+180 µm and the chemical analysis of the Kuru Columbite ore of the concentration test using scrubbing process revealed that the economic liberation (-250+180 µm) have the highest assay of 48.6% Nb2O5. Kuru Columbite Ore has successfully being upgraded from 11.4% to 48.6% via repeated scrubbing process.