Browsing by Author "Tshibob, Nawej Bob"

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    Investigating the effect of counter-current precipitation of cobalt hydroxide on its quality and MgO consumption rate
    (2024) Tshibob, Nawej Bob
    In this work, a different configuration for precipitating cobalt hydroxide is investigated and presented in order to enhance the cobalt hydroxide quality and maximize the utilization of magnesium oxide. The proposed configuration includes a precipitation step in presence of sodium sulphate using magnesium oxide to recover cobalt from cobalt-bearing solution, followed by a cobalt hydroxide washing step to fully utilize the excess or residual magnesium oxide using acidic cobalt-bearing solution. The results of precipitation experiments showed that using 4g/L of sulphate ions at 25°C, a magnesia dosage of 1.10g of MgO/g Co, and precipitation duration of 4 hours, approximately 99% of cobalt can be recovered in the precipitation step while leaving 87% of the manganese in solution. The equilibrium pH at precipitation stage was 8.42. The washing experiments' findings demonstrated that the cobalt hydroxide quality could be significantly improved by using an acidic cobalt sulphate solution as the washing solution, with cobalt upgrading of approximately 8% at 45°C, a washing solution volume of 350ml, and a washing time of 4 hours. The equilibrium pH at washing stage was 7.36. The ability of cobalt sulphate solution to lower or remove the excess or undissolved magnesium oxide which enhances the upgrading of cobalt hydroxide while maximizing the MgO usage was demonstrated. A reduction in magnesium oxide consumption rate of roughly 18% was evaluated as the effect of washing