Browsing by Author "OLUFEMI, Ademola S."

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    Process Intensification of Colemanite Leaching Using Sulfuric Acid in a Batch Reactor
    (International Journal of Engineering Research and General Science, 2016) OLAYEBI, Oluwafemi O.; OLUFEMI, Ademola S.; AZEEZ, Mayowa A.
    This contribution investigated methods of intensifying the leaching of colemanite using sulphuric acid for the improvement of boric acid recovery. Boric acid is one of the most commonly used boron compounds produced by dissolving colemanite (2CaO⋅3B2O3⋅5H2O) in aqueous sulfuric acid which results in the formation of gypsum (CaSO4⋅2H2O) as a by-product and must be separated from the main product. The dissolution of colemanite gives the amount of boric acid formed; the purity and crystallization of boric acid are affected by filtration of gypsum. In this study, and the factors that were examined in this study were stirrer agitation speed, particle size, reaction temperature on the dissolution of colemanite in the reaction of boric acid production. Colemanite having the same elemental chemical composition and particle size, sulfuric acid and distilled water were used as reactants for the boric acid production reaction in this study. The crushing of the colemanites were one in a jaw crusher, ground in a hammer mill and then sieved. The biggest diameter of the colemanite minerals was 150 μm and the experiments were performed at different particle sizes of colemanite (0-150, 0-250 and 250-1000 μm), temperatures (70- 90 °C) and stirring speed (350-500 rpm). The results obtained, showed that increasing the acid concentration results in a significant increase boric acid recovery. The highest recovery was obtained at 85 °C temperature. Increasing the mixing speed form 350 rpm to 500 rpm increased the recovery by 5.5%. Thus, the increase in agitating speed from 350 to 500 rpm resulted in a significant increase in boric acid recovery. Thus, it was concluded that agitation have a significant effect on boric acid recovery above 500 rpm. The batch process proved to be better than the semi-batch process in terms of the amount of boric acid recovered.