Browsing by Author "Onwualu AP"

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    Characterization of barite ores from selected locations in Nigeria for drilling fluid formulation
    (2021) Abraham EI; Bayode BL; Olubambi PA; Adetunji AR; Onwualu AP
    Barite is a non-metallic mineral composed of barium sulfate and is largely used by the oil and gas industry during drilling operations to control reservoir pressure. According to the American Petroleum Institute (API) standard, the specific gravity of barite should be a minimum of 4.1 to be applied as an additive in drilling fluid. In Nigeria, barite deposits are found in veins and cavity fillings hosted by varieties of rocks. Despite the abundance of barites reserves in Nigeria, the barites used in the Nigerian oil industry are imported from other countries. Therefore, in this research, barite deposits in some selected troughs in Nigeria were sampled and studied to determine their chemical composition and suitability as drilling fluid additives. The specific gravity of barites in the following states: Nasarawa, Benue, Plateau, Cross River, and Taraba was determined using the Pycnometer method, and their values were found to range from 2.9 to 4.3 on average. The quality of barite varies from location to location and with depth. The barite quality was enhanced when some low-grade barites were blended with a high grade, as shown in the blended samples of Plateau States, where specific gravity increased from 2.9 to 3.7. The results of XRF, E.D.X. and S.E.M. analysis of the samples show a predominance of BaO, Fe2O3, SrSO4, and SiO2. Samples from Benue (89.4% BaSO4) and Taraba (96.5% BaSO4) States met API standard for drilling mud application in terms of chemical composition, specific gravity, and a particle size distribution, while samples from Cross River (83.16% BaSO4), Nasarawa (77% BaSO4), and Plateau (10.88% BaSO4) States need to be upgraded to meet the standard for usage as drilling fluid additives. However, they can be used as extenders or fillers in the rubber and paper industry.
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    Mechanical behaviour of composite produced with quarry dust and rice husk ash for sustainable building applications
    (2022) Taiwo LA; Obianyo II; Omoniyi AO; Onwualu AP; Soboyejo AB; Amu OO
    Over the years, the cost and environmental issues with the utilization of conventional building materials such as cement and river sand for housing projects kept increasing with the increase in the human population. This has led researchers to explore alternative building materials that are affordable and sustainable. This study is aimed at developing a sustainable composite using quarry dust (QD) and rice husk ash (RHA). Different percentages of QD and RHA (5%, 10%, 15%, 20% and 25% wt/wt) were used for the partial replacement of river sand and cement respectively to produce non-conventional composite samples and conventional composite samples were produced using cement and river sand. The produced composites were moulded into block samples and cured at different curing ages (7, 14, 21, 28 and 56 days). Compressive strength results of the block samples were obtained using a Universal testing machine. The compressive strength of the samples increased with an increase in the curing age. The bulk density of non-conventional composite samples was found to be lower than that of conventional composite samples. The failure pattern of the conventional composite samples showed several localized shear surfaces/multiple cracks while that of non-conventional composite samples indicated delamination of outer surfaces. The study indicates that QD and RHA could be used for partial replacement of river sand and cement respectively in developing sustainable building materials.