Abstract

The air flotation technique has been employed in this study to explore the beneficiation of Lejja iron ore. The ore samples were obtained from Dunuoka in Lejja, in the Nsukka Local Government Area of the State of Enugu, Nigeria. The ore was pulverised, and the chemical composition of the ore was determined using XRF, and the mineral phases present were determined using XRD. The result of the chemical analysis of the head sample revealed 60.80% Fe₂O₃ (68.30% Fe), 29.55% SiO₂ (2.00% Si), 2.10% Al₂O₃ (0.19% Al), TiO₂, 0.11% CaO, and other minor elements in trace quality. The mineralogical analysis using the XRD showed that the ore contained haematite (Fe₂O₃) (001), magnetite (Fe₃O₄) (220), goethite (FeOOH) (303), CaC (101), Al₂O₃ (102), Fe₂O₃ (112), Fe₂O₃ (224), Fe₂O₃ (221), Fe₂O₃ (234), Fe₂O₃ (112), Fe₂O₃ (202), CaOAl₂O₃SiO₂, Al₂O₃ (102), CaC (101), Al₂O (102), F₂O₃ (112), CaC (111), Fe₂O₃ (102), CaO. Al₂O. SiO₂ (207), Al₂O₃ (112), CaO (111), MnO (101), and Ca₃Si₂O₇ (202). The ore was upgraded using the flotation technique, which contains 60.59% Fe₂O₃ (78.12% Fe), 3.54% SiO₂ (2.33% Si), 2.44% Al₂O₃ (0.23% Al), and other minor elements in trace quality. The FTIR analysis was performed within a wavelength range of 439.88 cm⁻¹ to 3951.02 cm⁻¹. The results identified several characteristic absorption bands related to various functional groups, including Fe-O stretching vibrations, Si-O-Si asymmetric stretching, H-O-H bending vibrations, and hydroxyl group vibrations. The Lejja iron ore exhibited strong absorption peaks at 460.7 cm⁻¹, 1046.96 cm⁻¹, 1627.56 cm⁻¹, 3485.24 cm⁻¹, and 3826.16 cm⁻¹, corresponding to Fe-O stretching, Si-O-Si asymmetric stretching, H-O-H bending, and hydroxyl group vibrations. Transmission Electron Microscopy (TEM) analysis revealed the nanoscale properties of Lejja iron ores. The particle size distribution showed 30 nm. The distribution of particle sizes revealed three ranges: less than 15 nm, 15–30 nm, and greater than 30 nm. The ore particles were divided into three sizes: medium (15–20 nm), giant (20–27 nm), and small (10–15 nm). Morphological investigations revealed the uneven shape of the Lejja ore particles. The ore was upgraded from 68.30% Fe to 78.12% Fe, and the recovery and concentration ratios were computed as 93% and 1.14, respectively. The study shows how air flotation methods enhanced the quality of Lejja iron ore.

Key words: Iron grade, impurity level, beneficiation, Lejja Iron Ore, and flotation process.