Browsing by Author "Baba, A.A"
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Item BLEACHING OF A NIGERIAN KAOLIN BY OXALIC ACID LEACHING(University of Chemical Technology and Metallurgy, 2015) Baba, A.A; Masobalaje, M.A; Ibrahim, A.S; Girigisu, S; Eletta, O.A; Fasakin, I.A; Aluko, I; Adekola, F.AThe level of improvement of whiteness of Egbeda (Nigeria) kaolin ore by oxalic acid leaching was investigated. The effects of acid concentration, reaction temperature and particle size on the extent of the ore dissolution were examined. The results of the leaching investigation on the improvement of the ore whiteness assessment were found to increase with increasing acid concentration, reaction temperature and decreasing particle size. At optimal leaching (0.5 mol L-1 H2C2O4, 85°C, 120 minutes) with moderate stirring, the dissolution reached 79.9 %, when total iron removal was achieved as evidenced from the EDXRF and EDS analyses. The dissolution curves were analyzed and found to conform to the surface chemical reaction, and the calculated activation energy of 41.34 kJ mol-1 supported the proposed model. These results are also corroborated by the output of the Post-Hoc test by Duncan Univariate Anova Analysis using SPSS 7.1. Finally, oxalic acid proved to be effective for treating the Egbeda (Nigeria) kaolin ore for total iron impurities removal and improving the ore whiteness for possible industrial utilities. Keywords: kaolin ore, Nigeria, leaching, oxalic acid, bleaching, iron impurities removal.Item Dissolution Kinetics Studies of Nigeria Gypsum Ore in Hydrochloric Acid(2018) Adekola, F.A.; Adebayo, I.O.; Baba, A.A; Adebayo, S.ADissolution kinetics studies of gypsum ore sourced from Postikum, Northern Nigeria, was conducted using hydrochloric acid as the leachant. The study was done with the aim of establishing possibility for the development of hydrometallurgical route for the production of highly pure gypsum. The effects of the experimental variables investigated were contact time, acid concentration, temperature, particles size and solid-liquid ration. The energy of activation of the dissolution reaction estimated from experimental data is 9.6kJ mol-1. Leaching in 6 M HCl solution, at temperature of 80oC, stirring speed of 400 rpm and using -90 + 63 µm particles size resulted in 99.7% dissolution of the ore within 120 min. The ore and the leached residue were characterized using X-ray Fluorescence (XRF), X-ray Diffraction (XRD), and Scanning Election Microscope (SEM) coupled with energy dispersive spectroscopy techniques (EDS) for chemical composition, phase and morphology. Statistical analysis of the kinetic dissolution data show that the chemical controlled model best describes the gypsum dissolution in hydrochloric acid.